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linux/fs/ext4/mballoc.c
Lukas Bulwahn afcc4e32f6 ext4: scope ret locally in ext4_try_to_trim_range() 
As commit 6920b39132 ("ext4: add new helper interface
ext4_try_to_trim_range()") moves some code into the separate function
ext4_try_to_trim_range(), the use of the variable ret within that
function is more limited and can be adjusted as well.

Scope the use of the variable ret locally and drop dead assignments.

No functional change.

Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Link: https://lore.kernel.org/r/20210820120853.23134-1-lukas.bulwahn@gmail.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2021-11-04 10:33:25 -04:00

6532 lines
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// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (c) 2003-2006, Cluster File Systems, Inc, info@clusterfs.com
* Written by Alex Tomas <alex@clusterfs.com>
*/
/*
* mballoc.c contains the multiblocks allocation routines
*/
#include "ext4_jbd2.h"
#include "mballoc.h"
#include <linux/log2.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/nospec.h>
#include <linux/backing-dev.h>
#include <trace/events/ext4.h>
/*
* MUSTDO:
* - test ext4_ext_search_left() and ext4_ext_search_right()
* - search for metadata in few groups
*
* TODO v4:
* - normalization should take into account whether file is still open
* - discard preallocations if no free space left (policy?)
* - don't normalize tails
* - quota
* - reservation for superuser
*
* TODO v3:
* - bitmap read-ahead (proposed by Oleg Drokin aka green)
* - track min/max extents in each group for better group selection
* - mb_mark_used() may allocate chunk right after splitting buddy
* - tree of groups sorted by number of free blocks
* - error handling
*/
/*
* The allocation request involve request for multiple number of blocks
* near to the goal(block) value specified.
*
* During initialization phase of the allocator we decide to use the
* group preallocation or inode preallocation depending on the size of
* the file. The size of the file could be the resulting file size we
* would have after allocation, or the current file size, which ever
* is larger. If the size is less than sbi->s_mb_stream_request we
* select to use the group preallocation. The default value of
* s_mb_stream_request is 16 blocks. This can also be tuned via
* /sys/fs/ext4/<partition>/mb_stream_req. The value is represented in
* terms of number of blocks.
*
* The main motivation for having small file use group preallocation is to
* ensure that we have small files closer together on the disk.
*
* First stage the allocator looks at the inode prealloc list,
* ext4_inode_info->i_prealloc_list, which contains list of prealloc
* spaces for this particular inode. The inode prealloc space is
* represented as:
*
* pa_lstart -> the logical start block for this prealloc space
* pa_pstart -> the physical start block for this prealloc space
* pa_len -> length for this prealloc space (in clusters)
* pa_free -> free space available in this prealloc space (in clusters)
*
* The inode preallocation space is used looking at the _logical_ start
* block. If only the logical file block falls within the range of prealloc
* space we will consume the particular prealloc space. This makes sure that
* we have contiguous physical blocks representing the file blocks
*
* The important thing to be noted in case of inode prealloc space is that
* we don't modify the values associated to inode prealloc space except
* pa_free.
*
* If we are not able to find blocks in the inode prealloc space and if we
* have the group allocation flag set then we look at the locality group
* prealloc space. These are per CPU prealloc list represented as
*
* ext4_sb_info.s_locality_groups[smp_processor_id()]
*
* The reason for having a per cpu locality group is to reduce the contention
* between CPUs. It is possible to get scheduled at this point.
*
* The locality group prealloc space is used looking at whether we have
* enough free space (pa_free) within the prealloc space.
*
* If we can't allocate blocks via inode prealloc or/and locality group
* prealloc then we look at the buddy cache. The buddy cache is represented
* by ext4_sb_info.s_buddy_cache (struct inode) whose file offset gets
* mapped to the buddy and bitmap information regarding different
* groups. The buddy information is attached to buddy cache inode so that
* we can access them through the page cache. The information regarding
* each group is loaded via ext4_mb_load_buddy. The information involve
* block bitmap and buddy information. The information are stored in the
* inode as:
*
* { page }
* [ group 0 bitmap][ group 0 buddy] [group 1][ group 1]...
*
*
* one block each for bitmap and buddy information. So for each group we
* take up 2 blocks. A page can contain blocks_per_page (PAGE_SIZE /
* blocksize) blocks. So it can have information regarding groups_per_page
* which is blocks_per_page/2
*
* The buddy cache inode is not stored on disk. The inode is thrown
* away when the filesystem is unmounted.
*
* We look for count number of blocks in the buddy cache. If we were able
* to locate that many free blocks we return with additional information
* regarding rest of the contiguous physical block available
*
* Before allocating blocks via buddy cache we normalize the request
* blocks. This ensure we ask for more blocks that we needed. The extra
* blocks that we get after allocation is added to the respective prealloc
* list. In case of inode preallocation we follow a list of heuristics
* based on file size. This can be found in ext4_mb_normalize_request. If
* we are doing a group prealloc we try to normalize the request to
* sbi->s_mb_group_prealloc. The default value of s_mb_group_prealloc is
* dependent on the cluster size; for non-bigalloc file systems, it is
* 512 blocks. This can be tuned via
* /sys/fs/ext4/<partition>/mb_group_prealloc. The value is represented in
* terms of number of blocks. If we have mounted the file system with -O
* stripe=<value> option the group prealloc request is normalized to the
* smallest multiple of the stripe value (sbi->s_stripe) which is
* greater than the default mb_group_prealloc.
*
* If "mb_optimize_scan" mount option is set, we maintain in memory group info
* structures in two data structures:
*
* 1) Array of largest free order lists (sbi->s_mb_largest_free_orders)
*
* Locking: sbi->s_mb_largest_free_orders_locks(array of rw locks)
*
* This is an array of lists where the index in the array represents the
* largest free order in the buddy bitmap of the participating group infos of
* that list. So, there are exactly MB_NUM_ORDERS(sb) (which means total
* number of buddy bitmap orders possible) number of lists. Group-infos are
* placed in appropriate lists.
*
* 2) Average fragment size rb tree (sbi->s_mb_avg_fragment_size_root)
*
* Locking: sbi->s_mb_rb_lock (rwlock)
*
* This is a red black tree consisting of group infos and the tree is sorted
* by average fragment sizes (which is calculated as ext4_group_info->bb_free
* / ext4_group_info->bb_fragments).
*
* When "mb_optimize_scan" mount option is set, mballoc consults the above data
* structures to decide the order in which groups are to be traversed for
* fulfilling an allocation request.
*
* At CR = 0, we look for groups which have the largest_free_order >= the order
* of the request. We directly look at the largest free order list in the data
* structure (1) above where largest_free_order = order of the request. If that
* list is empty, we look at remaining list in the increasing order of
* largest_free_order. This allows us to perform CR = 0 lookup in O(1) time.
*
* At CR = 1, we only consider groups where average fragment size > request
* size. So, we lookup a group which has average fragment size just above or
* equal to request size using our rb tree (data structure 2) in O(log N) time.
*
* If "mb_optimize_scan" mount option is not set, mballoc traverses groups in
* linear order which requires O(N) search time for each CR 0 and CR 1 phase.
*
* The regular allocator (using the buddy cache) supports a few tunables.
*
* /sys/fs/ext4/<partition>/mb_min_to_scan
* /sys/fs/ext4/<partition>/mb_max_to_scan
* /sys/fs/ext4/<partition>/mb_order2_req
* /sys/fs/ext4/<partition>/mb_linear_limit
*
* The regular allocator uses buddy scan only if the request len is power of
* 2 blocks and the order of allocation is >= sbi->s_mb_order2_reqs. The
* value of s_mb_order2_reqs can be tuned via
* /sys/fs/ext4/<partition>/mb_order2_req. If the request len is equal to
* stripe size (sbi->s_stripe), we try to search for contiguous block in
* stripe size. This should result in better allocation on RAID setups. If
* not, we search in the specific group using bitmap for best extents. The
* tunable min_to_scan and max_to_scan control the behaviour here.
* min_to_scan indicate how long the mballoc __must__ look for a best
* extent and max_to_scan indicates how long the mballoc __can__ look for a
* best extent in the found extents. Searching for the blocks starts with
* the group specified as the goal value in allocation context via
* ac_g_ex. Each group is first checked based on the criteria whether it
* can be used for allocation. ext4_mb_good_group explains how the groups are
* checked.
*
* When "mb_optimize_scan" is turned on, as mentioned above, the groups may not
* get traversed linearly. That may result in subsequent allocations being not
* close to each other. And so, the underlying device may get filled up in a
* non-linear fashion. While that may not matter on non-rotational devices, for
* rotational devices that may result in higher seek times. "mb_linear_limit"
* tells mballoc how many groups mballoc should search linearly before
* performing consulting above data structures for more efficient lookups. For
* non rotational devices, this value defaults to 0 and for rotational devices
* this is set to MB_DEFAULT_LINEAR_LIMIT.
*
* Both the prealloc space are getting populated as above. So for the first
* request we will hit the buddy cache which will result in this prealloc
* space getting filled. The prealloc space is then later used for the
* subsequent request.
*/
/*
* mballoc operates on the following data:
* - on-disk bitmap
* - in-core buddy (actually includes buddy and bitmap)
* - preallocation descriptors (PAs)
*
* there are two types of preallocations:
* - inode
* assiged to specific inode and can be used for this inode only.
* it describes part of inode's space preallocated to specific
* physical blocks. any block from that preallocated can be used
* independent. the descriptor just tracks number of blocks left
* unused. so, before taking some block from descriptor, one must
* make sure corresponded logical block isn't allocated yet. this
* also means that freeing any block within descriptor's range
* must discard all preallocated blocks.
* - locality group
* assigned to specific locality group which does not translate to
* permanent set of inodes: inode can join and leave group. space
* from this type of preallocation can be used for any inode. thus
* it's consumed from the beginning to the end.
*
* relation between them can be expressed as:
* in-core buddy = on-disk bitmap + preallocation descriptors
*
* this mean blocks mballoc considers used are:
* - allocated blocks (persistent)
* - preallocated blocks (non-persistent)
*
* consistency in mballoc world means that at any time a block is either
* free or used in ALL structures. notice: "any time" should not be read
* literally -- time is discrete and delimited by locks.
*
* to keep it simple, we don't use block numbers, instead we count number of
* blocks: how many blocks marked used/free in on-disk bitmap, buddy and PA.
*
* all operations can be expressed as:
* - init buddy: buddy = on-disk + PAs
* - new PA: buddy += N; PA = N
* - use inode PA: on-disk += N; PA -= N
* - discard inode PA buddy -= on-disk - PA; PA = 0
* - use locality group PA on-disk += N; PA -= N
* - discard locality group PA buddy -= PA; PA = 0
* note: 'buddy -= on-disk - PA' is used to show that on-disk bitmap
* is used in real operation because we can't know actual used
* bits from PA, only from on-disk bitmap
*
* if we follow this strict logic, then all operations above should be atomic.
* given some of them can block, we'd have to use something like semaphores
* killing performance on high-end SMP hardware. let's try to relax it using
* the following knowledge:
* 1) if buddy is referenced, it's already initialized
* 2) while block is used in buddy and the buddy is referenced,
* nobody can re-allocate that block
* 3) we work on bitmaps and '+' actually means 'set bits'. if on-disk has
* bit set and PA claims same block, it's OK. IOW, one can set bit in
* on-disk bitmap if buddy has same bit set or/and PA covers corresponded
* block
*
* so, now we're building a concurrency table:
* - init buddy vs.
* - new PA
* blocks for PA are allocated in the buddy, buddy must be referenced
* until PA is linked to allocation group to avoid concurrent buddy init
* - use inode PA
* we need to make sure that either on-disk bitmap or PA has uptodate data
* given (3) we care that PA-=N operation doesn't interfere with init
* - discard inode PA
* the simplest way would be to have buddy initialized by the discard
* - use locality group PA
* again PA-=N must be serialized with init
* - discard locality group PA
* the simplest way would be to have buddy initialized by the discard
* - new PA vs.
* - use inode PA
* i_data_sem serializes them
* - discard inode PA
* discard process must wait until PA isn't used by another process
* - use locality group PA
* some mutex should serialize them
* - discard locality group PA
* discard process must wait until PA isn't used by another process
* - use inode PA
* - use inode PA
* i_data_sem or another mutex should serializes them
* - discard inode PA
* discard process must wait until PA isn't used by another process
* - use locality group PA
* nothing wrong here -- they're different PAs covering different blocks
* - discard locality group PA
* discard process must wait until PA isn't used by another process
*
* now we're ready to make few consequences:
* - PA is referenced and while it is no discard is possible
* - PA is referenced until block isn't marked in on-disk bitmap
* - PA changes only after on-disk bitmap
* - discard must not compete with init. either init is done before
* any discard or they're serialized somehow
* - buddy init as sum of on-disk bitmap and PAs is done atomically
*
* a special case when we've used PA to emptiness. no need to modify buddy
* in this case, but we should care about concurrent init
*
*/
/*
* Logic in few words:
*
* - allocation:
* load group
* find blocks
* mark bits in on-disk bitmap
* release group
*
* - use preallocation:
* find proper PA (per-inode or group)
* load group
* mark bits in on-disk bitmap
* release group
* release PA
*
* - free:
* load group
* mark bits in on-disk bitmap
* release group
*
* - discard preallocations in group:
* mark PAs deleted
* move them onto local list
* load on-disk bitmap
* load group
* remove PA from object (inode or locality group)
* mark free blocks in-core
*
* - discard inode's preallocations:
*/
/*
* Locking rules
*
* Locks:
* - bitlock on a group (group)
* - object (inode/locality) (object)
* - per-pa lock (pa)
* - cr0 lists lock (cr0)
* - cr1 tree lock (cr1)
*
* Paths:
* - new pa
* object
* group
*
* - find and use pa:
* pa
*
* - release consumed pa:
* pa
* group
* object
*
* - generate in-core bitmap:
* group
* pa
*
* - discard all for given object (inode, locality group):
* object
* pa
* group
*
* - discard all for given group:
* group
* pa
* group
* object
*
* - allocation path (ext4_mb_regular_allocator)
* group
* cr0/cr1
*/
static struct kmem_cache *ext4_pspace_cachep;
static struct kmem_cache *ext4_ac_cachep;
static struct kmem_cache *ext4_free_data_cachep;
/* We create slab caches for groupinfo data structures based on the
* superblock block size. There will be one per mounted filesystem for
* each unique s_blocksize_bits */
#define NR_GRPINFO_CACHES 8
static struct kmem_cache *ext4_groupinfo_caches[NR_GRPINFO_CACHES];
static const char * const ext4_groupinfo_slab_names[NR_GRPINFO_CACHES] = {
"ext4_groupinfo_1k", "ext4_groupinfo_2k", "ext4_groupinfo_4k",
"ext4_groupinfo_8k", "ext4_groupinfo_16k", "ext4_groupinfo_32k",
"ext4_groupinfo_64k", "ext4_groupinfo_128k"
};
static void ext4_mb_generate_from_pa(struct super_block *sb, void *bitmap,
ext4_group_t group);
static void ext4_mb_generate_from_freelist(struct super_block *sb, void *bitmap,
ext4_group_t group);
static void ext4_mb_new_preallocation(struct ext4_allocation_context *ac);
static bool ext4_mb_good_group(struct ext4_allocation_context *ac,
ext4_group_t group, int cr);
static int ext4_try_to_trim_range(struct super_block *sb,
struct ext4_buddy *e4b, ext4_grpblk_t start,
ext4_grpblk_t max, ext4_grpblk_t minblocks);
/*
* The algorithm using this percpu seq counter goes below:
* 1. We sample the percpu discard_pa_seq counter before trying for block
* allocation in ext4_mb_new_blocks().
* 2. We increment this percpu discard_pa_seq counter when we either allocate
* or free these blocks i.e. while marking those blocks as used/free in
* mb_mark_used()/mb_free_blocks().
* 3. We also increment this percpu seq counter when we successfully identify
* that the bb_prealloc_list is not empty and hence proceed for discarding
* of those PAs inside ext4_mb_discard_group_preallocations().
*
* Now to make sure that the regular fast path of block allocation is not
* affected, as a small optimization we only sample the percpu seq counter
* on that cpu. Only when the block allocation fails and when freed blocks
* found were 0, that is when we sample percpu seq counter for all cpus using
* below function ext4_get_discard_pa_seq_sum(). This happens after making
* sure that all the PAs on grp->bb_prealloc_list got freed or if it's empty.
*/
static DEFINE_PER_CPU(u64, discard_pa_seq);
static inline u64 ext4_get_discard_pa_seq_sum(void)
{
int __cpu;
u64 __seq = 0;
for_each_possible_cpu(__cpu)
__seq += per_cpu(discard_pa_seq, __cpu);
return __seq;
}
static inline void *mb_correct_addr_and_bit(int *bit, void *addr)
{
#if BITS_PER_LONG == 64
*bit += ((unsigned long) addr & 7UL) << 3;
addr = (void *) ((unsigned long) addr & ~7UL);
#elif BITS_PER_LONG == 32
*bit += ((unsigned long) addr & 3UL) << 3;
addr = (void *) ((unsigned long) addr & ~3UL);
#else
#error "how many bits you are?!"
#endif
return addr;
}
static inline int mb_test_bit(int bit, void *addr)
{
/*
* ext4_test_bit on architecture like powerpc
* needs unsigned long aligned address
*/
addr = mb_correct_addr_and_bit(&bit, addr);
return ext4_test_bit(bit, addr);
}
static inline void mb_set_bit(int bit, void *addr)
{
addr = mb_correct_addr_and_bit(&bit, addr);
ext4_set_bit(bit, addr);
}
static inline void mb_clear_bit(int bit, void *addr)
{
addr = mb_correct_addr_and_bit(&bit, addr);
ext4_clear_bit(bit, addr);
}
static inline int mb_test_and_clear_bit(int bit, void *addr)
{
addr = mb_correct_addr_and_bit(&bit, addr);
return ext4_test_and_clear_bit(bit, addr);
}
static inline int mb_find_next_zero_bit(void *addr, int max, int start)
{
int fix = 0, ret, tmpmax;
addr = mb_correct_addr_and_bit(&fix, addr);
tmpmax = max + fix;
start += fix;
ret = ext4_find_next_zero_bit(addr, tmpmax, start) - fix;
if (ret > max)
return max;
return ret;
}
static inline int mb_find_next_bit(void *addr, int max, int start)
{
int fix = 0, ret, tmpmax;
addr = mb_correct_addr_and_bit(&fix, addr);
tmpmax = max + fix;
start += fix;
ret = ext4_find_next_bit(addr, tmpmax, start) - fix;
if (ret > max)
return max;
return ret;
}
static void *mb_find_buddy(struct ext4_buddy *e4b, int order, int *max)
{
char *bb;
BUG_ON(e4b->bd_bitmap == e4b->bd_buddy);
BUG_ON(max == NULL);
if (order > e4b->bd_blkbits + 1) {
*max = 0;
return NULL;
}
/* at order 0 we see each particular block */
if (order == 0) {
*max = 1 << (e4b->bd_blkbits + 3);
return e4b->bd_bitmap;
}
bb = e4b->bd_buddy + EXT4_SB(e4b->bd_sb)->s_mb_offsets[order];
*max = EXT4_SB(e4b->bd_sb)->s_mb_maxs[order];
return bb;
}
#ifdef DOUBLE_CHECK
static void mb_free_blocks_double(struct inode *inode, struct ext4_buddy *e4b,
int first, int count)
{
int i;
struct super_block *sb = e4b->bd_sb;
if (unlikely(e4b->bd_info->bb_bitmap == NULL))
return;
assert_spin_locked(ext4_group_lock_ptr(sb, e4b->bd_group));
for (i = 0; i < count; i++) {
if (!mb_test_bit(first + i, e4b->bd_info->bb_bitmap)) {
ext4_fsblk_t blocknr;
blocknr = ext4_group_first_block_no(sb, e4b->bd_group);
blocknr += EXT4_C2B(EXT4_SB(sb), first + i);
ext4_grp_locked_error(sb, e4b->bd_group,
inode ? inode->i_ino : 0,
blocknr,
"freeing block already freed "
"(bit %u)",
first + i);
ext4_mark_group_bitmap_corrupted(sb, e4b->bd_group,
EXT4_GROUP_INFO_BBITMAP_CORRUPT);
}
mb_clear_bit(first + i, e4b->bd_info->bb_bitmap);
}
}
static void mb_mark_used_double(struct ext4_buddy *e4b, int first, int count)
{
int i;
if (unlikely(e4b->bd_info->bb_bitmap == NULL))
return;
assert_spin_locked(ext4_group_lock_ptr(e4b->bd_sb, e4b->bd_group));
for (i = 0; i < count; i++) {
BUG_ON(mb_test_bit(first + i, e4b->bd_info->bb_bitmap));
mb_set_bit(first + i, e4b->bd_info->bb_bitmap);
}
}
static void mb_cmp_bitmaps(struct ext4_buddy *e4b, void *bitmap)
{
if (unlikely(e4b->bd_info->bb_bitmap == NULL))
return;
if (memcmp(e4b->bd_info->bb_bitmap, bitmap, e4b->bd_sb->s_blocksize)) {
unsigned char *b1, *b2;
int i;
b1 = (unsigned char *) e4b->bd_info->bb_bitmap;
b2 = (unsigned char *) bitmap;
for (i = 0; i < e4b->bd_sb->s_blocksize; i++) {
if (b1[i] != b2[i]) {
ext4_msg(e4b->bd_sb, KERN_ERR,
"corruption in group %u "
"at byte %u(%u): %x in copy != %x "
"on disk/prealloc",
e4b->bd_group, i, i * 8, b1[i], b2[i]);
BUG();
}
}
}
}
static void mb_group_bb_bitmap_alloc(struct super_block *sb,
struct ext4_group_info *grp, ext4_group_t group)
{
struct buffer_head *bh;
grp->bb_bitmap = kmalloc(sb->s_blocksize, GFP_NOFS);
if (!grp->bb_bitmap)
return;
bh = ext4_read_block_bitmap(sb, group);
if (IS_ERR_OR_NULL(bh)) {
kfree(grp->bb_bitmap);
grp->bb_bitmap = NULL;
return;
}
memcpy(grp->bb_bitmap, bh->b_data, sb->s_blocksize);
put_bh(bh);
}
static void mb_group_bb_bitmap_free(struct ext4_group_info *grp)
{
kfree(grp->bb_bitmap);
}
#else
static inline void mb_free_blocks_double(struct inode *inode,
struct ext4_buddy *e4b, int first, int count)
{
return;
}
static inline void mb_mark_used_double(struct ext4_buddy *e4b,
int first, int count)
{
return;
}
static inline void mb_cmp_bitmaps(struct ext4_buddy *e4b, void *bitmap)
{
return;
}
static inline void mb_group_bb_bitmap_alloc(struct super_block *sb,
struct ext4_group_info *grp, ext4_group_t group)
{
return;
}
static inline void mb_group_bb_bitmap_free(struct ext4_group_info *grp)
{
return;
}
#endif
#ifdef AGGRESSIVE_CHECK
#define MB_CHECK_ASSERT(assert) \
do { \
if (!(assert)) { \
printk(KERN_EMERG \
"Assertion failure in %s() at %s:%d: \"%s\"\n", \
function, file, line, # assert); \
BUG(); \
} \
} while (0)
static int __mb_check_buddy(struct ext4_buddy *e4b, char *file,
const char *function, int line)
{
struct super_block *sb = e4b->bd_sb;
int order = e4b->bd_blkbits + 1;
int max;
int max2;
int i;
int j;
int k;
int count;
struct ext4_group_info *grp;
int fragments = 0;
int fstart;
struct list_head *cur;
void *buddy;
void *buddy2;
if (e4b->bd_info->bb_check_counter++ % 10)
return 0;
while (order > 1) {
buddy = mb_find_buddy(e4b, order, &max);
MB_CHECK_ASSERT(buddy);
buddy2 = mb_find_buddy(e4b, order - 1, &max2);
MB_CHECK_ASSERT(buddy2);
MB_CHECK_ASSERT(buddy != buddy2);
MB_CHECK_ASSERT(max * 2 == max2);
count = 0;
for (i = 0; i < max; i++) {
if (mb_test_bit(i, buddy)) {
/* only single bit in buddy2 may be 1 */
if (!mb_test_bit(i << 1, buddy2)) {
MB_CHECK_ASSERT(
mb_test_bit((i<<1)+1, buddy2));
} else if (!mb_test_bit((i << 1) + 1, buddy2)) {
MB_CHECK_ASSERT(
mb_test_bit(i << 1, buddy2));
}
continue;
}
/* both bits in buddy2 must be 1 */
MB_CHECK_ASSERT(mb_test_bit(i << 1, buddy2));
MB_CHECK_ASSERT(mb_test_bit((i << 1) + 1, buddy2));
for (j = 0; j < (1 << order); j++) {
k = (i * (1 << order)) + j;
MB_CHECK_ASSERT(
!mb_test_bit(k, e4b->bd_bitmap));
}
count++;
}
MB_CHECK_ASSERT(e4b->bd_info->bb_counters[order] == count);
order--;
}
fstart = -1;
buddy = mb_find_buddy(e4b, 0, &max);
for (i = 0; i < max; i++) {
if (!mb_test_bit(i, buddy)) {
MB_CHECK_ASSERT(i >= e4b->bd_info->bb_first_free);
if (fstart == -1) {
fragments++;
fstart = i;
}
continue;
}
fstart = -1;
/* check used bits only */
for (j = 0; j < e4b->bd_blkbits + 1; j++) {
buddy2 = mb_find_buddy(e4b, j, &max2);
k = i >> j;
MB_CHECK_ASSERT(k < max2);
MB_CHECK_ASSERT(mb_test_bit(k, buddy2));
}
}
MB_CHECK_ASSERT(!EXT4_MB_GRP_NEED_INIT(e4b->bd_info));
MB_CHECK_ASSERT(e4b->bd_info->bb_fragments == fragments);
grp = ext4_get_group_info(sb, e4b->bd_group);
list_for_each(cur, &grp->bb_prealloc_list) {
ext4_group_t groupnr;
struct ext4_prealloc_space *pa;
pa = list_entry(cur, struct ext4_prealloc_space, pa_group_list);
ext4_get_group_no_and_offset(sb, pa->pa_pstart, &groupnr, &k);
MB_CHECK_ASSERT(groupnr == e4b->bd_group);
for (i = 0; i < pa->pa_len; i++)
MB_CHECK_ASSERT(mb_test_bit(k + i, buddy));
}
return 0;
}
#undef MB_CHECK_ASSERT
#define mb_check_buddy(e4b) __mb_check_buddy(e4b, \
__FILE__, __func__, __LINE__)
#else
#define mb_check_buddy(e4b)
#endif
/*
* Divide blocks started from @first with length @len into
* smaller chunks with power of 2 blocks.
* Clear the bits in bitmap which the blocks of the chunk(s) covered,
* then increase bb_counters[] for corresponded chunk size.
*/
static void ext4_mb_mark_free_simple(struct super_block *sb,
void *buddy, ext4_grpblk_t first, ext4_grpblk_t len,
struct ext4_group_info *grp)
{
struct ext4_sb_info *sbi = EXT4_SB(sb);
ext4_grpblk_t min;
ext4_grpblk_t max;
ext4_grpblk_t chunk;
unsigned int border;
BUG_ON(len > EXT4_CLUSTERS_PER_GROUP(sb));
border = 2 << sb->s_blocksize_bits;
while (len > 0) {
/* find how many blocks can be covered since this position */
max = ffs(first | border) - 1;
/* find how many blocks of power 2 we need to mark */
min = fls(len) - 1;
if (max < min)
min = max;
chunk = 1 << min;
/* mark multiblock chunks only */
grp->bb_counters[min]++;
if (min > 0)
mb_clear_bit(first >> min,
buddy + sbi->s_mb_offsets[min]);
len -= chunk;
first += chunk;
}
}
static void ext4_mb_rb_insert(struct rb_root *root, struct rb_node *new,
int (*cmp)(struct rb_node *, struct rb_node *))
{
struct rb_node **iter = &root->rb_node, *parent = NULL;
while (*iter) {
parent = *iter;
if (cmp(new, *iter) > 0)
iter = &((*iter)->rb_left);
else
iter = &((*iter)->rb_right);
}
rb_link_node(new, parent, iter);
rb_insert_color(new, root);
}
static int
ext4_mb_avg_fragment_size_cmp(struct rb_node *rb1, struct rb_node *rb2)
{
struct ext4_group_info *grp1 = rb_entry(rb1,
struct ext4_group_info,
bb_avg_fragment_size_rb);
struct ext4_group_info *grp2 = rb_entry(rb2,
struct ext4_group_info,
bb_avg_fragment_size_rb);
int num_frags_1, num_frags_2;
num_frags_1 = grp1->bb_fragments ?
grp1->bb_free / grp1->bb_fragments : 0;
num_frags_2 = grp2->bb_fragments ?
grp2->bb_free / grp2->bb_fragments : 0;
return (num_frags_2 - num_frags_1);
}
/*
* Reinsert grpinfo into the avg_fragment_size tree with new average
* fragment size.
*/
static void
mb_update_avg_fragment_size(struct super_block *sb, struct ext4_group_info *grp)
{
struct ext4_sb_info *sbi = EXT4_SB(sb);
if (!test_opt2(sb, MB_OPTIMIZE_SCAN) || grp->bb_free == 0)
return;
write_lock(&sbi->s_mb_rb_lock);
if (!RB_EMPTY_NODE(&grp->bb_avg_fragment_size_rb)) {
rb_erase(&grp->bb_avg_fragment_size_rb,
&sbi->s_mb_avg_fragment_size_root);
RB_CLEAR_NODE(&grp->bb_avg_fragment_size_rb);
}
ext4_mb_rb_insert(&sbi->s_mb_avg_fragment_size_root,
&grp->bb_avg_fragment_size_rb,
ext4_mb_avg_fragment_size_cmp);
write_unlock(&sbi->s_mb_rb_lock);
}
/*
* Choose next group by traversing largest_free_order lists. Updates *new_cr if
* cr level needs an update.
*/
static void ext4_mb_choose_next_group_cr0(struct ext4_allocation_context *ac,
int *new_cr, ext4_group_t *group, ext4_group_t ngroups)
{
struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
struct ext4_group_info *iter, *grp;
int i;
if (ac->ac_status == AC_STATUS_FOUND)
return;
if (unlikely(sbi->s_mb_stats && ac->ac_flags & EXT4_MB_CR0_OPTIMIZED))
atomic_inc(&sbi->s_bal_cr0_bad_suggestions);
grp = NULL;
for (i = ac->ac_2order; i < MB_NUM_ORDERS(ac->ac_sb); i++) {
if (list_empty(&sbi->s_mb_largest_free_orders[i]))
continue;
read_lock(&sbi->s_mb_largest_free_orders_locks[i]);
if (list_empty(&sbi->s_mb_largest_free_orders[i])) {
read_unlock(&sbi->s_mb_largest_free_orders_locks[i]);
continue;
}
grp = NULL;
list_for_each_entry(iter, &sbi->s_mb_largest_free_orders[i],
bb_largest_free_order_node) {
if (sbi->s_mb_stats)
atomic64_inc(&sbi->s_bal_cX_groups_considered[0]);
if (likely(ext4_mb_good_group(ac, iter->bb_group, 0))) {
grp = iter;
break;
}
}
read_unlock(&sbi->s_mb_largest_free_orders_locks[i]);
if (grp)
break;
}
if (!grp) {
/* Increment cr and search again */
*new_cr = 1;
} else {
*group = grp->bb_group;
ac->ac_last_optimal_group = *group;
ac->ac_flags |= EXT4_MB_CR0_OPTIMIZED;
}
}
/*
* Choose next group by traversing average fragment size tree. Updates *new_cr
* if cr lvel needs an update. Sets EXT4_MB_SEARCH_NEXT_LINEAR to indicate that
* the linear search should continue for one iteration since there's lock
* contention on the rb tree lock.
*/
static void ext4_mb_choose_next_group_cr1(struct ext4_allocation_context *ac,
int *new_cr, ext4_group_t *group, ext4_group_t ngroups)
{
struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
int avg_fragment_size, best_so_far;
struct rb_node *node, *found;
struct ext4_group_info *grp;
/*
* If there is contention on the lock, instead of waiting for the lock
* to become available, just continue searching lineraly. We'll resume
* our rb tree search later starting at ac->ac_last_optimal_group.
*/
if (!read_trylock(&sbi->s_mb_rb_lock)) {
ac->ac_flags |= EXT4_MB_SEARCH_NEXT_LINEAR;
return;
}
if (unlikely(ac->ac_flags & EXT4_MB_CR1_OPTIMIZED)) {
if (sbi->s_mb_stats)
atomic_inc(&sbi->s_bal_cr1_bad_suggestions);
/* We have found something at CR 1 in the past */
grp = ext4_get_group_info(ac->ac_sb, ac->ac_last_optimal_group);
for (found = rb_next(&grp->bb_avg_fragment_size_rb); found != NULL;
found = rb_next(found)) {
grp = rb_entry(found, struct ext4_group_info,
bb_avg_fragment_size_rb);
if (sbi->s_mb_stats)
atomic64_inc(&sbi->s_bal_cX_groups_considered[1]);
if (likely(ext4_mb_good_group(ac, grp->bb_group, 1)))
break;
}
goto done;
}
node = sbi->s_mb_avg_fragment_size_root.rb_node;
best_so_far = 0;
found = NULL;
while (node) {
grp = rb_entry(node, struct ext4_group_info,
bb_avg_fragment_size_rb);
avg_fragment_size = 0;
if (ext4_mb_good_group(ac, grp->bb_group, 1)) {
avg_fragment_size = grp->bb_fragments ?
grp->bb_free / grp->bb_fragments : 0;
if (!best_so_far || avg_fragment_size < best_so_far) {
best_so_far = avg_fragment_size;
found = node;
}
}
if (avg_fragment_size > ac->ac_g_ex.fe_len)
node = node->rb_right;
else
node = node->rb_left;
}
done:
if (found) {
grp = rb_entry(found, struct ext4_group_info,
bb_avg_fragment_size_rb);
*group = grp->bb_group;
ac->ac_flags |= EXT4_MB_CR1_OPTIMIZED;
} else {
*new_cr = 2;
}
read_unlock(&sbi->s_mb_rb_lock);
ac->ac_last_optimal_group = *group;
}
static inline int should_optimize_scan(struct ext4_allocation_context *ac)
{
if (unlikely(!test_opt2(ac->ac_sb, MB_OPTIMIZE_SCAN)))
return 0;
if (ac->ac_criteria >= 2)
return 0;
if (ext4_test_inode_flag(ac->ac_inode, EXT4_INODE_EXTENTS))
return 0;
return 1;
}
/*
* Return next linear group for allocation. If linear traversal should not be
* performed, this function just returns the same group
*/
static int
next_linear_group(struct ext4_allocation_context *ac, int group, int ngroups)
{
if (!should_optimize_scan(ac))
goto inc_and_return;
if (ac->ac_groups_linear_remaining) {
ac->ac_groups_linear_remaining--;
goto inc_and_return;
}
if (ac->ac_flags & EXT4_MB_SEARCH_NEXT_LINEAR) {
ac->ac_flags &= ~EXT4_MB_SEARCH_NEXT_LINEAR;
goto inc_and_return;
}
return group;
inc_and_return:
/*
* Artificially restricted ngroups for non-extent
* files makes group > ngroups possible on first loop.
*/
return group + 1 >= ngroups ? 0 : group + 1;
}
/*
* ext4_mb_choose_next_group: choose next group for allocation.
*
* @ac Allocation Context
* @new_cr This is an output parameter. If the there is no good group
* available at current CR level, this field is updated to indicate
* the new cr level that should be used.
* @group This is an input / output parameter. As an input it indicates the
* next group that the allocator intends to use for allocation. As
* output, this field indicates the next group that should be used as
* determined by the optimization functions.
* @ngroups Total number of groups
*/
static void ext4_mb_choose_next_group(struct ext4_allocation_context *ac,
int *new_cr, ext4_group_t *group, ext4_group_t ngroups)
{
*new_cr = ac->ac_criteria;
if (!should_optimize_scan(ac) || ac->ac_groups_linear_remaining)
return;
if (*new_cr == 0) {
ext4_mb_choose_next_group_cr0(ac, new_cr, group, ngroups);
} else if (*new_cr == 1) {
ext4_mb_choose_next_group_cr1(ac, new_cr, group, ngroups);
} else {
/*
* TODO: For CR=2, we can arrange groups in an rb tree sorted by
* bb_free. But until that happens, we should never come here.
*/
WARN_ON(1);
}
}
/*
* Cache the order of the largest free extent we have available in this block
* group.
*/
static void
mb_set_largest_free_order(struct super_block *sb, struct ext4_group_info *grp)
{
struct ext4_sb_info *sbi = EXT4_SB(sb);
int i;
if (test_opt2(sb, MB_OPTIMIZE_SCAN) && grp->bb_largest_free_order >= 0) {
write_lock(&sbi->s_mb_largest_free_orders_locks[
grp->bb_largest_free_order]);
list_del_init(&grp->bb_largest_free_order_node);
write_unlock(&sbi->s_mb_largest_free_orders_locks[
grp->bb_largest_free_order]);
}
grp->bb_largest_free_order = -1; /* uninit */
for (i = MB_NUM_ORDERS(sb) - 1; i >= 0; i--) {
if (grp->bb_counters[i] > 0) {
grp->bb_largest_free_order = i;
break;
}
}
if (test_opt2(sb, MB_OPTIMIZE_SCAN) &&
grp->bb_largest_free_order >= 0 && grp->bb_free) {
write_lock(&sbi->s_mb_largest_free_orders_locks[
grp->bb_largest_free_order]);
list_add_tail(&grp->bb_largest_free_order_node,
&sbi->s_mb_largest_free_orders[grp->bb_largest_free_order]);
write_unlock(&sbi->s_mb_largest_free_orders_locks[
grp->bb_largest_free_order]);
}
}
static noinline_for_stack
void ext4_mb_generate_buddy(struct super_block *sb,
void *buddy, void *bitmap, ext4_group_t group)
{
struct ext4_group_info *grp = ext4_get_group_info(sb, group);
struct ext4_sb_info *sbi = EXT4_SB(sb);
ext4_grpblk_t max = EXT4_CLUSTERS_PER_GROUP(sb);
ext4_grpblk_t i = 0;
ext4_grpblk_t first;
ext4_grpblk_t len;
unsigned free = 0;
unsigned fragments = 0;
unsigned long long period = get_cycles();
/* initialize buddy from bitmap which is aggregation
* of on-disk bitmap and preallocations */
i = mb_find_next_zero_bit(bitmap, max, 0);
grp->bb_first_free = i;
while (i < max) {
fragments++;
first = i;
i = mb_find_next_bit(bitmap, max, i);
len = i - first;
free += len;
if (len > 1)
ext4_mb_mark_free_simple(sb, buddy, first, len, grp);
else
grp->bb_counters[0]++;
if (i < max)
i = mb_find_next_zero_bit(bitmap, max, i);
}
grp->bb_fragments = fragments;
if (free != grp->bb_free) {
ext4_grp_locked_error(sb, group, 0, 0,
"block bitmap and bg descriptor "
"inconsistent: %u vs %u free clusters",
free, grp->bb_free);
/*
* If we intend to continue, we consider group descriptor
* corrupt and update bb_free using bitmap value
*/
grp->bb_free = free;
ext4_mark_group_bitmap_corrupted(sb, group,
EXT4_GROUP_INFO_BBITMAP_CORRUPT);
}
mb_set_largest_free_order(sb, grp);
clear_bit(EXT4_GROUP_INFO_NEED_INIT_BIT, &(grp->bb_state));
period = get_cycles() - period;
atomic_inc(&sbi->s_mb_buddies_generated);
atomic64_add(period, &sbi->s_mb_generation_time);
mb_update_avg_fragment_size(sb, grp);
}
/* The buddy information is attached the buddy cache inode
* for convenience. The information regarding each group
* is loaded via ext4_mb_load_buddy. The information involve
* block bitmap and buddy information. The information are
* stored in the inode as
*
* { page }
* [ group 0 bitmap][ group 0 buddy] [group 1][ group 1]...
*
*
* one block each for bitmap and buddy information.
* So for each group we take up 2 blocks. A page can
* contain blocks_per_page (PAGE_SIZE / blocksize) blocks.
* So it can have information regarding groups_per_page which
* is blocks_per_page/2
*
* Locking note: This routine takes the block group lock of all groups
* for this page; do not hold this lock when calling this routine!
*/
static int ext4_mb_init_cache(struct page *page, char *incore, gfp_t gfp)
{
ext4_group_t ngroups;
int blocksize;
int blocks_per_page;
int groups_per_page;
int err = 0;
int i;
ext4_group_t first_group, group;
int first_block;
struct super_block *sb;
struct buffer_head *bhs;
struct buffer_head **bh = NULL;
struct inode *inode;
char *data;
char *bitmap;
struct ext4_group_info *grinfo;
inode = page->mapping->host;
sb = inode->i_sb;
ngroups = ext4_get_groups_count(sb);
blocksize = i_blocksize(inode);
blocks_per_page = PAGE_SIZE / blocksize;
mb_debug(sb, "init page %lu\n", page->index);
groups_per_page = blocks_per_page >> 1;
if (groups_per_page == 0)
groups_per_page = 1;
/* allocate buffer_heads to read bitmaps */
if (groups_per_page > 1) {
i = sizeof(struct buffer_head *) * groups_per_page;
bh = kzalloc(i, gfp);
if (bh == NULL) {
err = -ENOMEM;
goto out;
}
} else
bh = &bhs;
first_group = page->index * blocks_per_page / 2;
/* read all groups the page covers into the cache */
for (i = 0, group = first_group; i < groups_per_page; i++, group++) {
if (group >= ngroups)
break;
grinfo = ext4_get_group_info(sb, group);
/*
* If page is uptodate then we came here after online resize
* which added some new uninitialized group info structs, so
* we must skip all initialized uptodate buddies on the page,
* which may be currently in use by an allocating task.
*/
if (PageUptodate(page) && !EXT4_MB_GRP_NEED_INIT(grinfo)) {
bh[i] = NULL;
continue;
}
bh[i] = ext4_read_block_bitmap_nowait(sb, group, false);
if (IS_ERR(bh[i])) {
err = PTR_ERR(bh[i]);
bh[i] = NULL;
goto out;
}
mb_debug(sb, "read bitmap for group %u\n", group);
}
/* wait for I/O completion */
for (i = 0, group = first_group; i < groups_per_page; i++, group++) {
int err2;
if (!bh[i])
continue;
err2 = ext4_wait_block_bitmap(sb, group, bh[i]);
if (!err)
err = err2;
}
first_block = page->index * blocks_per_page;
for (i = 0; i < blocks_per_page; i++) {
group = (first_block + i) >> 1;
if (group >= ngroups)
break;
if (!bh[group - first_group])
/* skip initialized uptodate buddy */
continue;
if (!buffer_verified(bh[group - first_group]))
/* Skip faulty bitmaps */
continue;
err = 0;
/*
* data carry information regarding this
* particular group in the format specified
* above
*
*/
data = page_address(page) + (i * blocksize);
bitmap = bh[group - first_group]->b_data;
/*
* We place the buddy block and bitmap block
* close together
*/
if ((first_block + i) & 1) {
/* this is block of buddy */
BUG_ON(incore == NULL);
mb_debug(sb, "put buddy for group %u in page %lu/%x\n",
group, page->index, i * blocksize);
trace_ext4_mb_buddy_bitmap_load(sb, group);
grinfo = ext4_get_group_info(sb, group);
grinfo->bb_fragments = 0;
memset(grinfo->bb_counters, 0,
sizeof(*grinfo->bb_counters) *
(MB_NUM_ORDERS(sb)));
/*
* incore got set to the group block bitmap below
*/
ext4_lock_group(sb, group);
/* init the buddy */
memset(data, 0xff, blocksize);
ext4_mb_generate_buddy(sb, data, incore, group);
ext4_unlock_group(sb, group);
incore = NULL;
} else {
/* this is block of bitmap */
BUG_ON(incore != NULL);
mb_debug(sb, "put bitmap for group %u in page %lu/%x\n",
group, page->index, i * blocksize);
trace_ext4_mb_bitmap_load(sb, group);
/* see comments in ext4_mb_put_pa() */
ext4_lock_group(sb, group);
memcpy(data, bitmap, blocksize);
/* mark all preallocated blks used in in-core bitmap */
ext4_mb_generate_from_pa(sb, data, group);
ext4_mb_generate_from_freelist(sb, data, group);
ext4_unlock_group(sb, group);
/* set incore so that the buddy information can be
* generated using this
*/
incore = data;
}
}
SetPageUptodate(page);
out:
if (bh) {
for (i = 0; i < groups_per_page; i++)
brelse(bh[i]);
if (bh != &bhs)
kfree(bh);
}
return err;
}
/*
* Lock the buddy and bitmap pages. This make sure other parallel init_group
* on the same buddy page doesn't happen whild holding the buddy page lock.
* Return locked buddy and bitmap pages on e4b struct. If buddy and bitmap
* are on the same page e4b->bd_buddy_page is NULL and return value is 0.
*/
static int ext4_mb_get_buddy_page_lock(struct super_block *sb,
ext4_group_t group, struct ext4_buddy *e4b, gfp_t gfp)
{
struct inode *inode = EXT4_SB(sb)->s_buddy_cache;
int block, pnum, poff;
int blocks_per_page;
struct page *page;
e4b->bd_buddy_page = NULL;
e4b->bd_bitmap_page = NULL;
blocks_per_page = PAGE_SIZE / sb->s_blocksize;
/*
* the buddy cache inode stores the block bitmap
* and buddy information in consecutive blocks.
* So for each group we need two blocks.
*/
block = group * 2;
pnum = block / blocks_per_page;
poff = block % blocks_per_page;
page = find_or_create_page(inode->i_mapping, pnum, gfp);
if (!page)
return -ENOMEM;
BUG_ON(page->mapping != inode->i_mapping);
e4b->bd_bitmap_page = page;
e4b->bd_bitmap = page_address(page) + (poff * sb->s_blocksize);
if (blocks_per_page >= 2) {
/* buddy and bitmap are on the same page */
return 0;
}
block++;
pnum = block / blocks_per_page;
page = find_or_create_page(inode->i_mapping, pnum, gfp);
if (!page)
return -ENOMEM;
BUG_ON(page->mapping != inode->i_mapping);
e4b->bd_buddy_page = page;
return 0;
}
static void ext4_mb_put_buddy_page_lock(struct ext4_buddy *e4b)
{
if (e4b->bd_bitmap_page) {
unlock_page(e4b->bd_bitmap_page);
put_page(e4b->bd_bitmap_page);
}
if (e4b->bd_buddy_page) {
unlock_page(e4b->bd_buddy_page);
put_page(e4b->bd_buddy_page);
}
}
/*
* Locking note: This routine calls ext4_mb_init_cache(), which takes the
* block group lock of all groups for this page; do not hold the BG lock when
* calling this routine!
*/
static noinline_for_stack
int ext4_mb_init_group(struct super_block *sb, ext4_group_t group, gfp_t gfp)
{
struct ext4_group_info *this_grp;
struct ext4_buddy e4b;
struct page *page;
int ret = 0;
might_sleep();
mb_debug(sb, "init group %u\n", group);
this_grp = ext4_get_group_info(sb, group);
/*
* This ensures that we don't reinit the buddy cache
* page which map to the group from which we are already
* allocating. If we are looking at the buddy cache we would
* have taken a reference using ext4_mb_load_buddy and that
* would have pinned buddy page to page cache.
* The call to ext4_mb_get_buddy_page_lock will mark the
* page accessed.
*/
ret = ext4_mb_get_buddy_page_lock(sb, group, &e4b, gfp);
if (ret || !EXT4_MB_GRP_NEED_INIT(this_grp)) {
/*
* somebody initialized the group
* return without doing anything
*/
goto err;
}
page = e4b.bd_bitmap_page;
ret = ext4_mb_init_cache(page, NULL, gfp);
if (ret)
goto err;
if (!PageUptodate(page)) {
ret = -EIO;
goto err;
}
if (e4b.bd_buddy_page == NULL) {
/*
* If both the bitmap and buddy are in
* the same page we don't need to force
* init the buddy
*/
ret = 0;
goto err;
}
/* init buddy cache */
page = e4b.bd_buddy_page;
ret = ext4_mb_init_cache(page, e4b.bd_bitmap, gfp);
if (ret)
goto err;
if (!PageUptodate(page)) {
ret = -EIO;
goto err;
}
err:
ext4_mb_put_buddy_page_lock(&e4b);
return ret;
}
/*
* Locking note: This routine calls ext4_mb_init_cache(), which takes the
* block group lock of all groups for this page; do not hold the BG lock when
* calling this routine!
*/
static noinline_for_stack int
ext4_mb_load_buddy_gfp(struct super_block *sb, ext4_group_t group,
struct ext4_buddy *e4b, gfp_t gfp)
{
int blocks_per_page;
int block;
int pnum;
int poff;
struct page *page;
int ret;
struct ext4_group_info *grp;
struct ext4_sb_info *sbi = EXT4_SB(sb);
struct inode *inode = sbi->s_buddy_cache;
might_sleep();
mb_debug(sb, "load group %u\n", group);
blocks_per_page = PAGE_SIZE / sb->s_blocksize;
grp = ext4_get_group_info(sb, group);
e4b->bd_blkbits = sb->s_blocksize_bits;
e4b->bd_info = grp;
e4b->bd_sb = sb;
e4b->bd_group = group;
e4b->bd_buddy_page = NULL;
e4b->bd_bitmap_page = NULL;
if (unlikely(EXT4_MB_GRP_NEED_INIT(grp))) {
/*
* we need full data about the group
* to make a good selection
*/
ret = ext4_mb_init_group(sb, group, gfp);
if (ret)
return ret;
}
/*
* the buddy cache inode stores the block bitmap
* and buddy information in consecutive blocks.
* So for each group we need two blocks.
*/
block = group * 2;
pnum = block / blocks_per_page;
poff = block % blocks_per_page;
/* we could use find_or_create_page(), but it locks page
* what we'd like to avoid in fast path ... */
page = find_get_page_flags(inode->i_mapping, pnum, FGP_ACCESSED);
if (page == NULL || !PageUptodate(page)) {
if (page)
/*
* drop the page reference and try
* to get the page with lock. If we
* are not uptodate that implies
* somebody just created the page but
* is yet to initialize the same. So
* wait for it to initialize.
*/
put_page(page);
page = find_or_create_page(inode->i_mapping, pnum, gfp);
if (page) {
BUG_ON(page->mapping != inode->i_mapping);
if (!PageUptodate(page)) {
ret = ext4_mb_init_cache(page, NULL, gfp);
if (ret) {
unlock_page(page);
goto err;
}
mb_cmp_bitmaps(e4b, page_address(page) +
(poff * sb->s_blocksize));
}
unlock_page(page);
}
}
if (page == NULL) {
ret = -ENOMEM;
goto err;
}
if (!PageUptodate(page)) {
ret = -EIO;
goto err;
}
/* Pages marked accessed already */
e4b->bd_bitmap_page = page;
e4b->bd_bitmap = page_address(page) + (poff * sb->s_blocksize);
block++;
pnum = block / blocks_per_page;
poff = block % blocks_per_page;
page = find_get_page_flags(inode->i_mapping, pnum, FGP_ACCESSED);
if (page == NULL || !PageUptodate(page)) {
if (page)
put_page(page);
page = find_or_create_page(inode->i_mapping, pnum, gfp);
if (page) {
BUG_ON(page->mapping != inode->i_mapping);
if (!PageUptodate(page)) {
ret = ext4_mb_init_cache(page, e4b->bd_bitmap,
gfp);
if (ret) {
unlock_page(page);
goto err;
}
}
unlock_page(page);
}
}
if (page == NULL) {
ret = -ENOMEM;
goto err;
}
if (!PageUptodate(page)) {
ret = -EIO;
goto err;
}
/* Pages marked accessed already */
e4b->bd_buddy_page = page;
e4b->bd_buddy = page_address(page) + (poff * sb->s_blocksize);
return 0;
err:
if (page)
put_page(page);
if (e4b->bd_bitmap_page)
put_page(e4b->bd_bitmap_page);
if (e4b->bd_buddy_page)
put_page(e4b->bd_buddy_page);
e4b->bd_buddy = NULL;
e4b->bd_bitmap = NULL;
return ret;
}
static int ext4_mb_load_buddy(struct super_block *sb, ext4_group_t group,
struct ext4_buddy *e4b)
{
return ext4_mb_load_buddy_gfp(sb, group, e4b, GFP_NOFS);
}
static void ext4_mb_unload_buddy(struct ext4_buddy *e4b)
{
if (e4b->bd_bitmap_page)
put_page(e4b->bd_bitmap_page);
if (e4b->bd_buddy_page)
put_page(e4b->bd_buddy_page);
}
static int mb_find_order_for_block(struct ext4_buddy *e4b, int block)
{
int order = 1, max;
void *bb;
BUG_ON(e4b->bd_bitmap == e4b->bd_buddy);
BUG_ON(block >= (1 << (e4b->bd_blkbits + 3)));
while (order <= e4b->bd_blkbits + 1) {
bb = mb_find_buddy(e4b, order, &max);
if (!mb_test_bit(block >> order, bb)) {
/* this block is part of buddy of order 'order' */
return order;
}
order++;
}
return 0;
}
static void mb_clear_bits(void *bm, int cur, int len)
{
__u32 *addr;
len = cur + len;
while (cur < len) {
if ((cur & 31) == 0 && (len - cur) >= 32) {
/* fast path: clear whole word at once */
addr = bm + (cur >> 3);
*addr = 0;
cur += 32;
continue;
}
mb_clear_bit(cur, bm);
cur++;
}
}
/* clear bits in given range
* will return first found zero bit if any, -1 otherwise
*/
static int mb_test_and_clear_bits(void *bm, int cur, int len)
{
__u32 *addr;
int zero_bit = -1;
len = cur + len;
while (cur < len) {
if ((cur & 31) == 0 && (len - cur) >= 32) {
/* fast path: clear whole word at once */
addr = bm + (cur >> 3);
if (*addr != (__u32)(-1) && zero_bit == -1)
zero_bit = cur + mb_find_next_zero_bit(addr, 32, 0);
*addr = 0;
cur += 32;
continue;
}
if (!mb_test_and_clear_bit(cur, bm) && zero_bit == -1)
zero_bit = cur;
cur++;
}
return zero_bit;
}
void ext4_set_bits(void *bm, int cur, int len)
{
__u32 *addr;
len = cur + len;
while (cur < len) {
if ((cur & 31) == 0 && (len - cur) >= 32) {
/* fast path: set whole word at once */
addr = bm + (cur >> 3);
*addr = 0xffffffff;
cur += 32;
continue;
}
mb_set_bit(cur, bm);
cur++;
}
}
static inline int mb_buddy_adjust_border(int* bit, void* bitmap, int side)
{
if (mb_test_bit(*bit + side, bitmap)) {
mb_clear_bit(*bit, bitmap);
(*bit) -= side;
return 1;
}
else {
(*bit) += side;
mb_set_bit(*bit, bitmap);
return -1;
}
}
static void mb_buddy_mark_free(struct ext4_buddy *e4b, int first, int last)
{
int max;
int order = 1;
void *buddy = mb_find_buddy(e4b, order, &max);
while (buddy) {
void *buddy2;
/* Bits in range [first; last] are known to be set since
* corresponding blocks were allocated. Bits in range
* (first; last) will stay set because they form buddies on
* upper layer. We just deal with borders if they don't
* align with upper layer and then go up.
* Releasing entire group is all about clearing
* single bit of highest order buddy.
*/
/* Example:
* ---------------------------------
* | 1 | 1 | 1 | 1 |
* ---------------------------------
* | 0 | 1 | 1 | 1 | 1 | 1 | 1 | 1 |
* ---------------------------------
* 0 1 2 3 4 5 6 7
* \_____________________/
*
* Neither [1] nor [6] is aligned to above layer.
* Left neighbour [0] is free, so mark it busy,
* decrease bb_counters and extend range to
* [0; 6]
* Right neighbour [7] is busy. It can't be coaleasced with [6], so
* mark [6] free, increase bb_counters and shrink range to
* [0; 5].
* Then shift range to [0; 2], go up and do the same.
*/
if (first & 1)
e4b->bd_info->bb_counters[order] += mb_buddy_adjust_border(&first, buddy, -1);
if (!(last & 1))
e4b->bd_info->bb_counters[order] += mb_buddy_adjust_border(&last, buddy, 1);
if (first > last)
break;
order++;
if (first == last || !(buddy2 = mb_find_buddy(e4b, order, &max))) {
mb_clear_bits(buddy, first, last - first + 1);
e4b->bd_info->bb_counters[order - 1] += last - first + 1;
break;
}
first >>= 1;
last >>= 1;
buddy = buddy2;
}
}
static void mb_free_blocks(struct inode *inode, struct ext4_buddy *e4b,
int first, int count)
{
int left_is_free = 0;
int right_is_free = 0;
int block;
int last = first + count - 1;
struct super_block *sb = e4b->bd_sb;
if (WARN_ON(count == 0))
return;
BUG_ON(last >= (sb->s_blocksize << 3));
assert_spin_locked(ext4_group_lock_ptr(sb, e4b->bd_group));
/* Don't bother if the block group is corrupt. */
if (unlikely(EXT4_MB_GRP_BBITMAP_CORRUPT(e4b->bd_info)))
return;
mb_check_buddy(e4b);
mb_free_blocks_double(inode, e4b, first, count);
this_cpu_inc(discard_pa_seq);
e4b->bd_info->bb_free += count;
if (first < e4b->bd_info->bb_first_free)
e4b->bd_info->bb_first_free = first;
/* access memory sequentially: check left neighbour,
* clear range and then check right neighbour
*/
if (first != 0)
left_is_free = !mb_test_bit(first - 1, e4b->bd_bitmap);
block = mb_test_and_clear_bits(e4b->bd_bitmap, first, count);
if (last + 1 < EXT4_SB(sb)->s_mb_maxs[0])
right_is_free = !mb_test_bit(last + 1, e4b->bd_bitmap);
if (unlikely(block != -1)) {
struct ext4_sb_info *sbi = EXT4_SB(sb);
ext4_fsblk_t blocknr;
blocknr = ext4_group_first_block_no(sb, e4b->bd_group);
blocknr += EXT4_C2B(sbi, block);
if (!(sbi->s_mount_state & EXT4_FC_REPLAY)) {
ext4_grp_locked_error(sb, e4b->bd_group,
inode ? inode->i_ino : 0,
blocknr,
"freeing already freed block (bit %u); block bitmap corrupt.",
block);
ext4_mark_group_bitmap_corrupted(
sb, e4b->bd_group,
EXT4_GROUP_INFO_BBITMAP_CORRUPT);
}
goto done;
}
/* let's maintain fragments counter */
if (left_is_free && right_is_free)
e4b->bd_info->bb_fragments--;
else if (!left_is_free && !right_is_free)
e4b->bd_info->bb_fragments++;
/* buddy[0] == bd_bitmap is a special case, so handle
* it right away and let mb_buddy_mark_free stay free of
* zero order checks.
* Check if neighbours are to be coaleasced,
* adjust bitmap bb_counters and borders appropriately.
*/
if (first & 1) {
first += !left_is_free;
e4b->bd_info->bb_counters[0] += left_is_free ? -1 : 1;
}
if (!(last & 1)) {
last -= !right_is_free;
e4b->bd_info->bb_counters[0] += right_is_free ? -1 : 1;
}
if (first <= last)
mb_buddy_mark_free(e4b, first >> 1, last >> 1);
done:
mb_set_largest_free_order(sb, e4b->bd_info);
mb_update_avg_fragment_size(sb, e4b->bd_info);
mb_check_buddy(e4b);
}
static int mb_find_extent(struct ext4_buddy *e4b, int block,
int needed, struct ext4_free_extent *ex)
{
int next = block;
int max, order;
void *buddy;
assert_spin_locked(ext4_group_lock_ptr(e4b->bd_sb, e4b->bd_group));
BUG_ON(ex == NULL);
buddy = mb_find_buddy(e4b, 0, &max);
BUG_ON(buddy == NULL);
BUG_ON(block >= max);
if (mb_test_bit(block, buddy)) {
ex->fe_len = 0;
ex->fe_start = 0;
ex->fe_group = 0;
return 0;
}
/* find actual order */
order = mb_find_order_for_block(e4b, block);
block = block >> order;
ex->fe_len = 1 << order;
ex->fe_start = block << order;
ex->fe_group = e4b->bd_group;
/* calc difference from given start */
next = next - ex->fe_start;
ex->fe_len -= next;
ex->fe_start += next;
while (needed > ex->fe_len &&
mb_find_buddy(e4b, order, &max)) {
if (block + 1 >= max)
break;
next = (block + 1) * (1 << order);
if (mb_test_bit(next, e4b->bd_bitmap))
break;
order = mb_find_order_for_block(e4b, next);
block = next >> order;
ex->fe_len += 1 << order;
}
if (ex->fe_start + ex->fe_len > EXT4_CLUSTERS_PER_GROUP(e4b->bd_sb)) {
/* Should never happen! (but apparently sometimes does?!?) */
WARN_ON(1);
ext4_grp_locked_error(e4b->bd_sb, e4b->bd_group, 0, 0,
"corruption or bug in mb_find_extent "
"block=%d, order=%d needed=%d ex=%u/%d/%d@%u",
block, order, needed, ex->fe_group, ex->fe_start,
ex->fe_len, ex->fe_logical);
ex->fe_len = 0;
ex->fe_start = 0;
ex->fe_group = 0;
}
return ex->fe_len;
}
static int mb_mark_used(struct ext4_buddy *e4b, struct ext4_free_extent *ex)
{
int ord;
int mlen = 0;
int max = 0;
int cur;
int start = ex->fe_start;
int len = ex->fe_len;
unsigned ret = 0;
int len0 = len;
void *buddy;
BUG_ON(start + len > (e4b->bd_sb->s_blocksize << 3));
BUG_ON(e4b->bd_group != ex->fe_group);
assert_spin_locked(ext4_group_lock_ptr(e4b->bd_sb, e4b->bd_group));
mb_check_buddy(e4b);
mb_mark_used_double(e4b, start, len);
this_cpu_inc(discard_pa_seq);
e4b->bd_info->bb_free -= len;
if (e4b->bd_info->bb_first_free == start)
e4b->bd_info->bb_first_free += len;
/* let's maintain fragments counter */
if (start != 0)
mlen = !mb_test_bit(start - 1, e4b->bd_bitmap);
if (start + len < EXT4_SB(e4b->bd_sb)->s_mb_maxs[0])
max = !mb_test_bit(start + len, e4b->bd_bitmap);
if (mlen && max)
e4b->bd_info->bb_fragments++;
else if (!mlen && !max)
e4b->bd_info->bb_fragments--;
/* let's maintain buddy itself */
while (len) {
ord = mb_find_order_for_block(e4b, start);
if (((start >> ord) << ord) == start && len >= (1 << ord)) {
/* the whole chunk may be allocated at once! */
mlen = 1 << ord;
buddy = mb_find_buddy(e4b, ord, &max);
BUG_ON((start >> ord) >= max);
mb_set_bit(start >> ord, buddy);
e4b->bd_info->bb_counters[ord]--;
start += mlen;
len -= mlen;
BUG_ON(len < 0);
continue;
}
/* store for history */
if (ret == 0)
ret = len | (ord << 16);
/* we have to split large buddy */
BUG_ON(ord <= 0);
buddy = mb_find_buddy(e4b, ord, &max);
mb_set_bit(start >> ord, buddy);
e4b->bd_info->bb_counters[ord]--;
ord--;
cur = (start >> ord) & ~1U;
buddy = mb_find_buddy(e4b, ord, &max);
mb_clear_bit(cur, buddy);
mb_clear_bit(cur + 1, buddy);
e4b->bd_info->bb_counters[ord]++;
e4b->bd_info->bb_counters[ord]++;
}
mb_set_largest_free_order(e4b->bd_sb, e4b->bd_info);
mb_update_avg_fragment_size(e4b->bd_sb, e4b->bd_info);
ext4_set_bits(e4b->bd_bitmap, ex->fe_start, len0);
mb_check_buddy(e4b);
return ret;
}
/*
* Must be called under group lock!
*/
static void ext4_mb_use_best_found(struct ext4_allocation_context *ac,
struct ext4_buddy *e4b)
{
struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
int ret;
BUG_ON(ac->ac_b_ex.fe_group != e4b->bd_group);
BUG_ON(ac->ac_status == AC_STATUS_FOUND);
ac->ac_b_ex.fe_len = min(ac->ac_b_ex.fe_len, ac->ac_g_ex.fe_len);
ac->ac_b_ex.fe_logical = ac->ac_g_ex.fe_logical;
ret = mb_mark_used(e4b, &ac->ac_b_ex);
/* preallocation can change ac_b_ex, thus we store actually
* allocated blocks for history */
ac->ac_f_ex = ac->ac_b_ex;
ac->ac_status = AC_STATUS_FOUND;
ac->ac_tail = ret & 0xffff;
ac->ac_buddy = ret >> 16;
/*
* take the page reference. We want the page to be pinned
* so that we don't get a ext4_mb_init_cache_call for this
* group until we update the bitmap. That would mean we
* double allocate blocks. The reference is dropped
* in ext4_mb_release_context
*/
ac->ac_bitmap_page = e4b->bd_bitmap_page;
get_page(ac->ac_bitmap_page);
ac->ac_buddy_page = e4b->bd_buddy_page;
get_page(ac->ac_buddy_page);
/* store last allocated for subsequent stream allocation */
if (ac->ac_flags & EXT4_MB_STREAM_ALLOC) {
spin_lock(&sbi->s_md_lock);
sbi->s_mb_last_group = ac->ac_f_ex.fe_group;
sbi->s_mb_last_start = ac->ac_f_ex.fe_start;
spin_unlock(&sbi->s_md_lock);
}
/*
* As we've just preallocated more space than
* user requested originally, we store allocated
* space in a special descriptor.
*/
if (ac->ac_o_ex.fe_len < ac->ac_b_ex.fe_len)
ext4_mb_new_preallocation(ac);
}
static void ext4_mb_check_limits(struct ext4_allocation_context *ac,
struct ext4_buddy *e4b,
int finish_group)
{
struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
struct ext4_free_extent *bex = &ac->ac_b_ex;
struct ext4_free_extent *gex = &ac->ac_g_ex;
struct ext4_free_extent ex;
int max;
if (ac->ac_status == AC_STATUS_FOUND)
return;
/*
* We don't want to scan for a whole year
*/
if (ac->ac_found > sbi->s_mb_max_to_scan &&
!(ac->ac_flags & EXT4_MB_HINT_FIRST)) {
ac->ac_status = AC_STATUS_BREAK;
return;
}
/*
* Haven't found good chunk so far, let's continue
*/
if (bex->fe_len < gex->fe_len)
return;
if ((finish_group || ac->ac_found > sbi->s_mb_min_to_scan)
&& bex->fe_group == e4b->bd_group) {
/* recheck chunk's availability - we don't know
* when it was found (within this lock-unlock
* period or not) */
max = mb_find_extent(e4b, bex->fe_start, gex->fe_len, &ex);
if (max >= gex->fe_len) {
ext4_mb_use_best_found(ac, e4b);
return;
}
}
}
/*
* The routine checks whether found extent is good enough. If it is,
* then the extent gets marked used and flag is set to the context
* to stop scanning. Otherwise, the extent is compared with the
* previous found extent and if new one is better, then it's stored
* in the context. Later, the best found extent will be used, if
* mballoc can't find good enough extent.
*
* FIXME: real allocation policy is to be designed yet!
*/
static void ext4_mb_measure_extent(struct ext4_allocation_context *ac,
struct ext4_free_extent *ex,
struct ext4_buddy *e4b)
{
struct ext4_free_extent *bex = &ac->ac_b_ex;
struct ext4_free_extent *gex = &ac->ac_g_ex;
BUG_ON(ex->fe_len <= 0);
BUG_ON(ex->fe_len > EXT4_CLUSTERS_PER_GROUP(ac->ac_sb));
BUG_ON(ex->fe_start >= EXT4_CLUSTERS_PER_GROUP(ac->ac_sb));
BUG_ON(ac->ac_status != AC_STATUS_CONTINUE);
ac->ac_found++;
/*
* The special case - take what you catch first
*/
if (unlikely(ac->ac_flags & EXT4_MB_HINT_FIRST)) {
*bex = *ex;
ext4_mb_use_best_found(ac, e4b);
return;
}
/*
* Let's check whether the chuck is good enough
*/
if (ex->fe_len == gex->fe_len) {
*bex = *ex;
ext4_mb_use_best_found(ac, e4b);
return;
}
/*
* If this is first found extent, just store it in the context
*/
if (bex->fe_len == 0) {
*bex = *ex;
return;
}
/*
* If new found extent is better, store it in the context
*/
if (bex->fe_len < gex->fe_len) {
/* if the request isn't satisfied, any found extent
* larger than previous best one is better */
if (ex->fe_len > bex->fe_len)
*bex = *ex;
} else if (ex->fe_len > gex->fe_len) {
/* if the request is satisfied, then we try to find
* an extent that still satisfy the request, but is
* smaller than previous one */
if (ex->fe_len < bex->fe_len)
*bex = *ex;
}
ext4_mb_check_limits(ac, e4b, 0);
}
static noinline_for_stack
int ext4_mb_try_best_found(struct ext4_allocation_context *ac,
struct ext4_buddy *e4b)
{
struct ext4_free_extent ex = ac->ac_b_ex;
ext4_group_t group = ex.fe_group;
int max;
int err;
BUG_ON(ex.fe_len <= 0);
err = ext4_mb_load_buddy(ac->ac_sb, group, e4b);
if (err)
return err;
ext4_lock_group(ac->ac_sb, group);
max = mb_find_extent(e4b, ex.fe_start, ex.fe_len, &ex);
if (max > 0) {
ac->ac_b_ex = ex;
ext4_mb_use_best_found(ac, e4b);
}
ext4_unlock_group(ac->ac_sb, group);
ext4_mb_unload_buddy(e4b);
return 0;
}
static noinline_for_stack
int ext4_mb_find_by_goal(struct ext4_allocation_context *ac,
struct ext4_buddy *e4b)
{
ext4_group_t group = ac->ac_g_ex.fe_group;
int max;
int err;
struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
struct ext4_group_info *grp = ext4_get_group_info(ac->ac_sb, group);
struct ext4_free_extent ex;
if (!(ac->ac_flags & EXT4_MB_HINT_TRY_GOAL))
return 0;
if (grp->bb_free == 0)
return 0;
err = ext4_mb_load_buddy(ac->ac_sb, group, e4b);
if (err)
return err;
if (unlikely(EXT4_MB_GRP_BBITMAP_CORRUPT(e4b->bd_info))) {
ext4_mb_unload_buddy(e4b);
return 0;
}
ext4_lock_group(ac->ac_sb, group);
max = mb_find_extent(e4b, ac->ac_g_ex.fe_start,
ac->ac_g_ex.fe_len, &ex);
ex.fe_logical = 0xDEADFA11; /* debug value */
if (max >= ac->ac_g_ex.fe_len && ac->ac_g_ex.fe_len == sbi->s_stripe) {
ext4_fsblk_t start;
start = ext4_group_first_block_no(ac->ac_sb, e4b->bd_group) +
ex.fe_start;
/* use do_div to get remainder (would be 64-bit modulo) */
if (do_div(start, sbi->s_stripe) == 0) {
ac->ac_found++;
ac->ac_b_ex = ex;
ext4_mb_use_best_found(ac, e4b);
}
} else if (max >= ac->ac_g_ex.fe_len) {
BUG_ON(ex.fe_len <= 0);
BUG_ON(ex.fe_group != ac->ac_g_ex.fe_group);
BUG_ON(ex.fe_start != ac->ac_g_ex.fe_start);
ac->ac_found++;
ac->ac_b_ex = ex;
ext4_mb_use_best_found(ac, e4b);
} else if (max > 0 && (ac->ac_flags & EXT4_MB_HINT_MERGE)) {
/* Sometimes, caller may want to merge even small
* number of blocks to an existing extent */
BUG_ON(ex.fe_len <= 0);
BUG_ON(ex.fe_group != ac->ac_g_ex.fe_group);
BUG_ON(ex.fe_start != ac->ac_g_ex.fe_start);
ac->ac_found++;
ac->ac_b_ex = ex;
ext4_mb_use_best_found(ac, e4b);
}
ext4_unlock_group(ac->ac_sb, group);
ext4_mb_unload_buddy(e4b);
return 0;
}
/*
* The routine scans buddy structures (not bitmap!) from given order
* to max order and tries to find big enough chunk to satisfy the req
*/
static noinline_for_stack
void ext4_mb_simple_scan_group(struct ext4_allocation_context *ac,
struct ext4_buddy *e4b)
{
struct super_block *sb = ac->ac_sb;
struct ext4_group_info *grp = e4b->bd_info;
void *buddy;
int i;
int k;
int max;
BUG_ON(ac->ac_2order <= 0);
for (i = ac->ac_2order; i < MB_NUM_ORDERS(sb); i++) {
if (grp->bb_counters[i] == 0)
continue;
buddy = mb_find_buddy(e4b, i, &max);
BUG_ON(buddy == NULL);
k = mb_find_next_zero_bit(buddy, max, 0);
if (k >= max) {
ext4_grp_locked_error(ac->ac_sb, e4b->bd_group, 0, 0,
"%d free clusters of order %d. But found 0",
grp->bb_counters[i], i);
ext4_mark_group_bitmap_corrupted(ac->ac_sb,
e4b->bd_group,
EXT4_GROUP_INFO_BBITMAP_CORRUPT);
break;
}
ac->ac_found++;
ac->ac_b_ex.fe_len = 1 << i;
ac->ac_b_ex.fe_start = k << i;
ac->ac_b_ex.fe_group = e4b->bd_group;
ext4_mb_use_best_found(ac, e4b);
BUG_ON(ac->ac_f_ex.fe_len != ac->ac_g_ex.fe_len);
if (EXT4_SB(sb)->s_mb_stats)
atomic_inc(&EXT4_SB(sb)->s_bal_2orders);
break;
}
}
/*
* The routine scans the group and measures all found extents.
* In order to optimize scanning, caller must pass number of
* free blocks in the group, so the routine can know upper limit.
*/
static noinline_for_stack
void ext4_mb_complex_scan_group(struct ext4_allocation_context *ac,
struct ext4_buddy *e4b)
{
struct super_block *sb = ac->ac_sb;
void *bitmap = e4b->bd_bitmap;
struct ext4_free_extent ex;
int i;
int free;
free = e4b->bd_info->bb_free;
if (WARN_ON(free <= 0))
return;
i = e4b->bd_info->bb_first_free;
while (free && ac->ac_status == AC_STATUS_CONTINUE) {
i = mb_find_next_zero_bit(bitmap,
EXT4_CLUSTERS_PER_GROUP(sb), i);
if (i >= EXT4_CLUSTERS_PER_GROUP(sb)) {
/*
* IF we have corrupt bitmap, we won't find any
* free blocks even though group info says we
* have free blocks
*/
ext4_grp_locked_error(sb, e4b->bd_group, 0, 0,
"%d free clusters as per "
"group info. But bitmap says 0",
free);
ext4_mark_group_bitmap_corrupted(sb, e4b->bd_group,
EXT4_GROUP_INFO_BBITMAP_CORRUPT);
break;
}
mb_find_extent(e4b, i, ac->ac_g_ex.fe_len, &ex);
if (WARN_ON(ex.fe_len <= 0))
break;
if (free < ex.fe_len) {
ext4_grp_locked_error(sb, e4b->bd_group, 0, 0,
"%d free clusters as per "
"group info. But got %d blocks",
free, ex.fe_len);
ext4_mark_group_bitmap_corrupted(sb, e4b->bd_group,
EXT4_GROUP_INFO_BBITMAP_CORRUPT);
/*
* The number of free blocks differs. This mostly
* indicate that the bitmap is corrupt. So exit
* without claiming the space.
*/
break;
}
ex.fe_logical = 0xDEADC0DE; /* debug value */
ext4_mb_measure_extent(ac, &ex, e4b);
i += ex.fe_len;
free -= ex.fe_len;
}
ext4_mb_check_limits(ac, e4b, 1);
}
/*
* This is a special case for storages like raid5
* we try to find stripe-aligned chunks for stripe-size-multiple requests
*/
static noinline_for_stack
void ext4_mb_scan_aligned(struct ext4_allocation_context *ac,
struct ext4_buddy *e4b)
{
struct super_block *sb = ac->ac_sb;
struct ext4_sb_info *sbi = EXT4_SB(sb);
void *bitmap = e4b->bd_bitmap;
struct ext4_free_extent ex;
ext4_fsblk_t first_group_block;
ext4_fsblk_t a;
ext4_grpblk_t i;
int max;
BUG_ON(sbi->s_stripe == 0);
/* find first stripe-aligned block in group */
first_group_block = ext4_group_first_block_no(sb, e4b->bd_group);
a = first_group_block + sbi->s_stripe - 1;
do_div(a, sbi->s_stripe);
i = (a * sbi->s_stripe) - first_group_block;
while (i < EXT4_CLUSTERS_PER_GROUP(sb)) {
if (!mb_test_bit(i, bitmap)) {
max = mb_find_extent(e4b, i, sbi->s_stripe, &ex);
if (max >= sbi->s_stripe) {
ac->ac_found++;
ex.fe_logical = 0xDEADF00D; /* debug value */
ac->ac_b_ex = ex;
ext4_mb_use_best_found(ac, e4b);
break;
}
}
i += sbi->s_stripe;
}
}
/*
* This is also called BEFORE we load the buddy bitmap.
* Returns either 1 or 0 indicating that the group is either suitable
* for the allocation or not.
*/
static bool ext4_mb_good_group(struct ext4_allocation_context *ac,
ext4_group_t group, int cr)
{
ext4_grpblk_t free, fragments;
int flex_size = ext4_flex_bg_size(EXT4_SB(ac->ac_sb));
struct ext4_group_info *grp = ext4_get_group_info(ac->ac_sb, group);
BUG_ON(cr < 0 || cr >= 4);
if (unlikely(EXT4_MB_GRP_BBITMAP_CORRUPT(grp)))
return false;
free = grp->bb_free;
if (free == 0)
return false;
fragments = grp->bb_fragments;
if (fragments == 0)
return false;
switch (cr) {
case 0:
BUG_ON(ac->ac_2order == 0);
/* Avoid using the first bg of a flexgroup for data files */
if ((ac->ac_flags & EXT4_MB_HINT_DATA) &&
(flex_size >= EXT4_FLEX_SIZE_DIR_ALLOC_SCHEME) &&
((group % flex_size) == 0))
return false;
if (free < ac->ac_g_ex.fe_len)
return false;
if (ac->ac_2order >= MB_NUM_ORDERS(ac->ac_sb))
return true;
if (grp->bb_largest_free_order < ac->ac_2order)
return false;
return true;
case 1:
if ((free / fragments) >= ac->ac_g_ex.fe_len)
return true;
break;
case 2:
if (free >= ac->ac_g_ex.fe_len)
return true;
break;
case 3:
return true;
default:
BUG();
}
return false;
}
/*
* This could return negative error code if something goes wrong
* during ext4_mb_init_group(). This should not be called with
* ext4_lock_group() held.
*
* Note: because we are conditionally operating with the group lock in
* the EXT4_MB_STRICT_CHECK case, we need to fake out sparse in this
* function using __acquire and __release. This means we need to be
* super careful before messing with the error path handling via "goto
* out"!
*/
static int ext4_mb_good_group_nolock(struct ext4_allocation_context *ac,
ext4_group_t group, int cr)
{
struct ext4_group_info *grp = ext4_get_group_info(ac->ac_sb, group);
struct super_block *sb = ac->ac_sb;
struct ext4_sb_info *sbi = EXT4_SB(sb);
bool should_lock = ac->ac_flags & EXT4_MB_STRICT_CHECK;
ext4_grpblk_t free;
int ret = 0;
if (sbi->s_mb_stats)
atomic64_inc(&sbi->s_bal_cX_groups_considered[ac->ac_criteria]);
if (should_lock) {
ext4_lock_group(sb, group);
__release(ext4_group_lock_ptr(sb, group));
}
free = grp->bb_free;
if (free == 0)
goto out;
if (cr <= 2 && free < ac->ac_g_ex.fe_len)
goto out;
if (unlikely(EXT4_MB_GRP_BBITMAP_CORRUPT(grp)))
goto out;
if (should_lock) {
__acquire(ext4_group_lock_ptr(sb, group));
ext4_unlock_group(sb, group);
}
/* We only do this if the grp has never been initialized */
if (unlikely(EXT4_MB_GRP_NEED_INIT(grp))) {
struct ext4_group_desc *gdp =
ext4_get_group_desc(sb, group, NULL);
int ret;
/* cr=0/1 is a very optimistic search to find large
* good chunks almost for free. If buddy data is not
* ready, then this optimization makes no sense. But
* we never skip the first block group in a flex_bg,
* since this gets used for metadata block allocation,
* and we want to make sure we locate metadata blocks
* in the first block group in the flex_bg if possible.
*/
if (cr < 2 &&
(!sbi->s_log_groups_per_flex ||
((group & ((1 << sbi->s_log_groups_per_flex) - 1)) != 0)) &&
!(ext4_has_group_desc_csum(sb) &&
(gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT))))
return 0;
ret = ext4_mb_init_group(sb, group, GFP_NOFS);
if (ret)
return ret;
}
if (should_lock) {
ext4_lock_group(sb, group);
__release(ext4_group_lock_ptr(sb, group));
}
ret = ext4_mb_good_group(ac, group, cr);
out:
if (should_lock) {
__acquire(ext4_group_lock_ptr(sb, group));
ext4_unlock_group(sb, group);
}
return ret;
}
/*
* Start prefetching @nr block bitmaps starting at @group.
* Return the next group which needs to be prefetched.
*/
ext4_group_t ext4_mb_prefetch(struct super_block *sb, ext4_group_t group,
unsigned int nr, int *cnt)
{
ext4_group_t ngroups = ext4_get_groups_count(sb);
struct buffer_head *bh;
struct blk_plug plug;
blk_start_plug(&plug);
while (nr-- > 0) {
struct ext4_group_desc *gdp = ext4_get_group_desc(sb, group,
NULL);
struct ext4_group_info *grp = ext4_get_group_info(sb, group);
/*
* Prefetch block groups with free blocks; but don't
* bother if it is marked uninitialized on disk, since
* it won't require I/O to read. Also only try to
* prefetch once, so we avoid getblk() call, which can
* be expensive.
*/
if (!EXT4_MB_GRP_TEST_AND_SET_READ(grp) &&
EXT4_MB_GRP_NEED_INIT(grp) &&
ext4_free_group_clusters(sb, gdp) > 0 &&
!(ext4_has_group_desc_csum(sb) &&
(gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)))) {
bh = ext4_read_block_bitmap_nowait(sb, group, true);
if (bh && !IS_ERR(bh)) {
if (!buffer_uptodate(bh) && cnt)
(*cnt)++;
brelse(bh);
}
}
if (++group >= ngroups)
group = 0;
}
blk_finish_plug(&plug);
return group;
}
/*
* Prefetching reads the block bitmap into the buffer cache; but we
* need to make sure that the buddy bitmap in the page cache has been
* initialized. Note that ext4_mb_init_group() will block if the I/O
* is not yet completed, or indeed if it was not initiated by
* ext4_mb_prefetch did not start the I/O.
*
* TODO: We should actually kick off the buddy bitmap setup in a work
* queue when the buffer I/O is completed, so that we don't block
* waiting for the block allocation bitmap read to finish when
* ext4_mb_prefetch_fini is called from ext4_mb_regular_allocator().
*/
void ext4_mb_prefetch_fini(struct super_block *sb, ext4_group_t group,
unsigned int nr)
{
while (nr-- > 0) {
struct ext4_group_desc *gdp = ext4_get_group_desc(sb, group,
NULL);
struct ext4_group_info *grp = ext4_get_group_info(sb, group);
if (!group)
group = ext4_get_groups_count(sb);
group--;
grp = ext4_get_group_info(sb, group);
if (EXT4_MB_GRP_NEED_INIT(grp) &&
ext4_free_group_clusters(sb, gdp) > 0 &&
!(ext4_has_group_desc_csum(sb) &&
(gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT)))) {
if (ext4_mb_init_group(sb, group, GFP_NOFS))
break;
}
}
}
static noinline_for_stack int
ext4_mb_regular_allocator(struct ext4_allocation_context *ac)
{
ext4_group_t prefetch_grp = 0, ngroups, group, i;
int cr = -1;
int err = 0, first_err = 0;
unsigned int nr = 0, prefetch_ios = 0;
struct ext4_sb_info *sbi;
struct super_block *sb;
struct ext4_buddy e4b;
int lost;
sb = ac->ac_sb;
sbi = EXT4_SB(sb);
ngroups = ext4_get_groups_count(sb);
/* non-extent files are limited to low blocks/groups */
if (!(ext4_test_inode_flag(ac->ac_inode, EXT4_INODE_EXTENTS)))
ngroups = sbi->s_blockfile_groups;
BUG_ON(ac->ac_status == AC_STATUS_FOUND);
/* first, try the goal */
err = ext4_mb_find_by_goal(ac, &e4b);
if (err || ac->ac_status == AC_STATUS_FOUND)
goto out;
if (unlikely(ac->ac_flags & EXT4_MB_HINT_GOAL_ONLY))
goto out;
/*
* ac->ac_2order is set only if the fe_len is a power of 2
* if ac->ac_2order is set we also set criteria to 0 so that we
* try exact allocation using buddy.
*/
i = fls(ac->ac_g_ex.fe_len);
ac->ac_2order = 0;
/*
* We search using buddy data only if the order of the request
* is greater than equal to the sbi_s_mb_order2_reqs
* You can tune it via /sys/fs/ext4/<partition>/mb_order2_req
* We also support searching for power-of-two requests only for
* requests upto maximum buddy size we have constructed.
*/
if (i >= sbi->s_mb_order2_reqs && i <= MB_NUM_ORDERS(sb)) {
/*
* This should tell if fe_len is exactly power of 2
*/
if ((ac->ac_g_ex.fe_len & (~(1 << (i - 1)))) == 0)
ac->ac_2order = array_index_nospec(i - 1,
MB_NUM_ORDERS(sb));
}
/* if stream allocation is enabled, use global goal */
if (ac->ac_flags & EXT4_MB_STREAM_ALLOC) {
/* TBD: may be hot point */
spin_lock(&sbi->s_md_lock);
ac->ac_g_ex.fe_group = sbi->s_mb_last_group;
ac->ac_g_ex.fe_start = sbi->s_mb_last_start;
spin_unlock(&sbi->s_md_lock);
}
/* Let's just scan groups to find more-less suitable blocks */
cr = ac->ac_2order ? 0 : 1;
/*
* cr == 0 try to get exact allocation,
* cr == 3 try to get anything
*/
repeat:
for (; cr < 4 && ac->ac_status == AC_STATUS_CONTINUE; cr++) {
ac->ac_criteria = cr;
/*
* searching for the right group start
* from the goal value specified
*/
group = ac->ac_g_ex.fe_group;
ac->ac_last_optimal_group = group;
ac->ac_groups_linear_remaining = sbi->s_mb_max_linear_groups;
prefetch_grp = group;
for (i = 0; i < ngroups; group = next_linear_group(ac, group, ngroups),
i++) {
int ret = 0, new_cr;
cond_resched();
ext4_mb_choose_next_group(ac, &new_cr, &group, ngroups);
if (new_cr != cr) {
cr = new_cr;
goto repeat;
}
/*
* Batch reads of the block allocation bitmaps
* to get multiple READs in flight; limit
* prefetching at cr=0/1, otherwise mballoc can
* spend a lot of time loading imperfect groups
*/
if ((prefetch_grp == group) &&
(cr > 1 ||
prefetch_ios < sbi->s_mb_prefetch_limit)) {
unsigned int curr_ios = prefetch_ios;
nr = sbi->s_mb_prefetch;
if (ext4_has_feature_flex_bg(sb)) {
nr = 1 << sbi->s_log_groups_per_flex;
nr -= group & (nr - 1);
nr = min(nr, sbi->s_mb_prefetch);
}
prefetch_grp = ext4_mb_prefetch(sb, group,
nr, &prefetch_ios);
if (prefetch_ios == curr_ios)
nr = 0;
}
/* This now checks without needing the buddy page */
ret = ext4_mb_good_group_nolock(ac, group, cr);
if (ret <= 0) {
if (!first_err)
first_err = ret;
continue;
}
err = ext4_mb_load_buddy(sb, group, &e4b);
if (err)
goto out;
ext4_lock_group(sb, group);
/*
* We need to check again after locking the
* block group
*/
ret = ext4_mb_good_group(ac, group, cr);
if (ret == 0) {
ext4_unlock_group(sb, group);
ext4_mb_unload_buddy(&e4b);
continue;
}
ac->ac_groups_scanned++;
if (cr == 0)
ext4_mb_simple_scan_group(ac, &e4b);
else if (cr == 1 && sbi->s_stripe &&
!(ac->ac_g_ex.fe_len % sbi->s_stripe))
ext4_mb_scan_aligned(ac, &e4b);
else
ext4_mb_complex_scan_group(ac, &e4b);
ext4_unlock_group(sb, group);
ext4_mb_unload_buddy(&e4b);
if (ac->ac_status != AC_STATUS_CONTINUE)
break;
}
/* Processed all groups and haven't found blocks */
if (sbi->s_mb_stats && i == ngroups)
atomic64_inc(&sbi->s_bal_cX_failed[cr]);
}
if (ac->ac_b_ex.fe_len > 0 && ac->ac_status != AC_STATUS_FOUND &&
!(ac->ac_flags & EXT4_MB_HINT_FIRST)) {
/*
* We've been searching too long. Let's try to allocate
* the best chunk we've found so far
*/
ext4_mb_try_best_found(ac, &e4b);
if (ac->ac_status != AC_STATUS_FOUND) {
/*
* Someone more lucky has already allocated it.
* The only thing we can do is just take first
* found block(s)
*/
lost = atomic_inc_return(&sbi->s_mb_lost_chunks);
mb_debug(sb, "lost chunk, group: %u, start: %d, len: %d, lost: %d\n",
ac->ac_b_ex.fe_group, ac->ac_b_ex.fe_start,
ac->ac_b_ex.fe_len, lost);
ac->ac_b_ex.fe_group = 0;
ac->ac_b_ex.fe_start = 0;
ac->ac_b_ex.fe_len = 0;
ac->ac_status = AC_STATUS_CONTINUE;
ac->ac_flags |= EXT4_MB_HINT_FIRST;
cr = 3;
goto repeat;
}
}
if (sbi->s_mb_stats && ac->ac_status == AC_STATUS_FOUND)
atomic64_inc(&sbi->s_bal_cX_hits[ac->ac_criteria]);
out:
if (!err && ac->ac_status != AC_STATUS_FOUND && first_err)
err = first_err;
mb_debug(sb, "Best len %d, origin len %d, ac_status %u, ac_flags 0x%x, cr %d ret %d\n",
ac->ac_b_ex.fe_len, ac->ac_o_ex.fe_len, ac->ac_status,
ac->ac_flags, cr, err);
if (nr)
ext4_mb_prefetch_fini(sb, prefetch_grp, nr);
return err;
}
static void *ext4_mb_seq_groups_start(struct seq_file *seq, loff_t *pos)
{
struct super_block *sb = PDE_DATA(file_inode(seq->file));
ext4_group_t group;
if (*pos < 0 || *pos >= ext4_get_groups_count(sb))
return NULL;
group = *pos + 1;
return (void *) ((unsigned long) group);
}
static void *ext4_mb_seq_groups_next(struct seq_file *seq, void *v, loff_t *pos)
{
struct super_block *sb = PDE_DATA(file_inode(seq->file));
ext4_group_t group;
++*pos;
if (*pos < 0 || *pos >= ext4_get_groups_count(sb))
return NULL;
group = *pos + 1;
return (void *) ((unsigned long) group);
}
static int ext4_mb_seq_groups_show(struct seq_file *seq, void *v)
{
struct super_block *sb = PDE_DATA(file_inode(seq->file));
ext4_group_t group = (ext4_group_t) ((unsigned long) v);
int i;
int err, buddy_loaded = 0;
struct ext4_buddy e4b;
struct ext4_group_info *grinfo;
unsigned char blocksize_bits = min_t(unsigned char,
sb->s_blocksize_bits,
EXT4_MAX_BLOCK_LOG_SIZE);
struct sg {
struct ext4_group_info info;
ext4_grpblk_t counters[EXT4_MAX_BLOCK_LOG_SIZE + 2];
} sg;
group--;
if (group == 0)
seq_puts(seq, "#group: free frags first ["
" 2^0 2^1 2^2 2^3 2^4 2^5 2^6 "
" 2^7 2^8 2^9 2^10 2^11 2^12 2^13 ]\n");
i = (blocksize_bits + 2) * sizeof(sg.info.bb_counters[0]) +
sizeof(struct ext4_group_info);
grinfo = ext4_get_group_info(sb, group);
/* Load the group info in memory only if not already loaded. */
if (unlikely(EXT4_MB_GRP_NEED_INIT(grinfo))) {
err = ext4_mb_load_buddy(sb, group, &e4b);
if (err) {
seq_printf(seq, "#%-5u: I/O error\n", group);
return 0;
}
buddy_loaded = 1;
}
memcpy(&sg, ext4_get_group_info(sb, group), i);
if (buddy_loaded)
ext4_mb_unload_buddy(&e4b);
seq_printf(seq, "#%-5u: %-5u %-5u %-5u [", group, sg.info.bb_free,
sg.info.bb_fragments, sg.info.bb_first_free);
for (i = 0; i <= 13; i++)
seq_printf(seq, " %-5u", i <= blocksize_bits + 1 ?
sg.info.bb_counters[i] : 0);
seq_puts(seq, " ]\n");
return 0;
}
static void ext4_mb_seq_groups_stop(struct seq_file *seq, void *v)
{
}
const struct seq_operations ext4_mb_seq_groups_ops = {
.start = ext4_mb_seq_groups_start,
.next = ext4_mb_seq_groups_next,
.stop = ext4_mb_seq_groups_stop,
.show = ext4_mb_seq_groups_show,
};
int ext4_seq_mb_stats_show(struct seq_file *seq, void *offset)
{
struct super_block *sb = (struct super_block *)seq->private;
struct ext4_sb_info *sbi = EXT4_SB(sb);
seq_puts(seq, "mballoc:\n");
if (!sbi->s_mb_stats) {
seq_puts(seq, "\tmb stats collection turned off.\n");
seq_puts(seq, "\tTo enable, please write \"1\" to sysfs file mb_stats.\n");
return 0;
}
seq_printf(seq, "\treqs: %u\n", atomic_read(&sbi->s_bal_reqs));
seq_printf(seq, "\tsuccess: %u\n", atomic_read(&sbi->s_bal_success));
seq_printf(seq, "\tgroups_scanned: %u\n", atomic_read(&sbi->s_bal_groups_scanned));
seq_puts(seq, "\tcr0_stats:\n");
seq_printf(seq, "\t\thits: %llu\n", atomic64_read(&sbi->s_bal_cX_hits[0]));
seq_printf(seq, "\t\tgroups_considered: %llu\n",
atomic64_read(&sbi->s_bal_cX_groups_considered[0]));
seq_printf(seq, "\t\tuseless_loops: %llu\n",
atomic64_read(&sbi->s_bal_cX_failed[0]));
seq_printf(seq, "\t\tbad_suggestions: %u\n",
atomic_read(&sbi->s_bal_cr0_bad_suggestions));
seq_puts(seq, "\tcr1_stats:\n");
seq_printf(seq, "\t\thits: %llu\n", atomic64_read(&sbi->s_bal_cX_hits[1]));
seq_printf(seq, "\t\tgroups_considered: %llu\n",
atomic64_read(&sbi->s_bal_cX_groups_considered[1]));
seq_printf(seq, "\t\tuseless_loops: %llu\n",
atomic64_read(&sbi->s_bal_cX_failed[1]));
seq_printf(seq, "\t\tbad_suggestions: %u\n",
atomic_read(&sbi->s_bal_cr1_bad_suggestions));
seq_puts(seq, "\tcr2_stats:\n");
seq_printf(seq, "\t\thits: %llu\n", atomic64_read(&sbi->s_bal_cX_hits[2]));
seq_printf(seq, "\t\tgroups_considered: %llu\n",
atomic64_read(&sbi->s_bal_cX_groups_considered[2]));
seq_printf(seq, "\t\tuseless_loops: %llu\n",
atomic64_read(&sbi->s_bal_cX_failed[2]));
seq_puts(seq, "\tcr3_stats:\n");
seq_printf(seq, "\t\thits: %llu\n", atomic64_read(&sbi->s_bal_cX_hits[3]));
seq_printf(seq, "\t\tgroups_considered: %llu\n",
atomic64_read(&sbi->s_bal_cX_groups_considered[3]));
seq_printf(seq, "\t\tuseless_loops: %llu\n",
atomic64_read(&sbi->s_bal_cX_failed[3]));
seq_printf(seq, "\textents_scanned: %u\n", atomic_read(&sbi->s_bal_ex_scanned));
seq_printf(seq, "\t\tgoal_hits: %u\n", atomic_read(&sbi->s_bal_goals));
seq_printf(seq, "\t\t2^n_hits: %u\n", atomic_read(&sbi->s_bal_2orders));
seq_printf(seq, "\t\tbreaks: %u\n", atomic_read(&sbi->s_bal_breaks));
seq_printf(seq, "\t\tlost: %u\n", atomic_read(&sbi->s_mb_lost_chunks));
seq_printf(seq, "\tbuddies_generated: %u/%u\n",
atomic_read(&sbi->s_mb_buddies_generated),
ext4_get_groups_count(sb));
seq_printf(seq, "\tbuddies_time_used: %llu\n",
atomic64_read(&sbi->s_mb_generation_time));
seq_printf(seq, "\tpreallocated: %u\n",
atomic_read(&sbi->s_mb_preallocated));
seq_printf(seq, "\tdiscarded: %u\n",
atomic_read(&sbi->s_mb_discarded));
return 0;
}
static void *ext4_mb_seq_structs_summary_start(struct seq_file *seq, loff_t *pos)
__acquires(&EXT4_SB(sb)->s_mb_rb_lock)
{
struct super_block *sb = PDE_DATA(file_inode(seq->file));
unsigned long position;
read_lock(&EXT4_SB(sb)->s_mb_rb_lock);
if (*pos < 0 || *pos >= MB_NUM_ORDERS(sb) + 1)
return NULL;
position = *pos + 1;
return (void *) ((unsigned long) position);
}
static void *ext4_mb_seq_structs_summary_next(struct seq_file *seq, void *v, loff_t *pos)
{
struct super_block *sb = PDE_DATA(file_inode(seq->file));
unsigned long position;
++*pos;
if (*pos < 0 || *pos >= MB_NUM_ORDERS(sb) + 1)
return NULL;
position = *pos + 1;
return (void *) ((unsigned long) position);
}
static int ext4_mb_seq_structs_summary_show(struct seq_file *seq, void *v)
{
struct super_block *sb = PDE_DATA(file_inode(seq->file));
struct ext4_sb_info *sbi = EXT4_SB(sb);
unsigned long position = ((unsigned long) v);
struct ext4_group_info *grp;
struct rb_node *n;
unsigned int count, min, max;
position--;
if (position >= MB_NUM_ORDERS(sb)) {
seq_puts(seq, "fragment_size_tree:\n");
n = rb_first(&sbi->s_mb_avg_fragment_size_root);
if (!n) {
seq_puts(seq, "\ttree_min: 0\n\ttree_max: 0\n\ttree_nodes: 0\n");
return 0;
}
grp = rb_entry(n, struct ext4_group_info, bb_avg_fragment_size_rb);
min = grp->bb_fragments ? grp->bb_free / grp->bb_fragments : 0;
count = 1;
while (rb_next(n)) {
count++;
n = rb_next(n);
}
grp = rb_entry(n, struct ext4_group_info, bb_avg_fragment_size_rb);
max = grp->bb_fragments ? grp->bb_free / grp->bb_fragments : 0;
seq_printf(seq, "\ttree_min: %u\n\ttree_max: %u\n\ttree_nodes: %u\n",
min, max, count);
return 0;
}
if (position == 0) {
seq_printf(seq, "optimize_scan: %d\n",
test_opt2(sb, MB_OPTIMIZE_SCAN) ? 1 : 0);
seq_puts(seq, "max_free_order_lists:\n");
}
count = 0;
list_for_each_entry(grp, &sbi->s_mb_largest_free_orders[position],
bb_largest_free_order_node)
count++;
seq_printf(seq, "\tlist_order_%u_groups: %u\n",
(unsigned int)position, count);
return 0;
}
static void ext4_mb_seq_structs_summary_stop(struct seq_file *seq, void *v)
__releases(&EXT4_SB(sb)->s_mb_rb_lock)
{
struct super_block *sb = PDE_DATA(file_inode(seq->file));
read_unlock(&EXT4_SB(sb)->s_mb_rb_lock);
}
const struct seq_operations ext4_mb_seq_structs_summary_ops = {
.start = ext4_mb_seq_structs_summary_start,
.next = ext4_mb_seq_structs_summary_next,
.stop = ext4_mb_seq_structs_summary_stop,
.show = ext4_mb_seq_structs_summary_show,
};
static struct kmem_cache *get_groupinfo_cache(int blocksize_bits)
{
int cache_index = blocksize_bits - EXT4_MIN_BLOCK_LOG_SIZE;
struct kmem_cache *cachep = ext4_groupinfo_caches[cache_index];
BUG_ON(!cachep);
return cachep;
}
/*
* Allocate the top-level s_group_info array for the specified number
* of groups
*/
int ext4_mb_alloc_groupinfo(struct super_block *sb, ext4_group_t ngroups)
{
struct ext4_sb_info *sbi = EXT4_SB(sb);
unsigned size;
struct ext4_group_info ***old_groupinfo, ***new_groupinfo;
size = (ngroups + EXT4_DESC_PER_BLOCK(sb) - 1) >>
EXT4_DESC_PER_BLOCK_BITS(sb);
if (size <= sbi->s_group_info_size)
return 0;
size = roundup_pow_of_two(sizeof(*sbi->s_group_info) * size);
new_groupinfo = kvzalloc(size, GFP_KERNEL);
if (!new_groupinfo) {
ext4_msg(sb, KERN_ERR, "can't allocate buddy meta group");
return -ENOMEM;
}
rcu_read_lock();
old_groupinfo = rcu_dereference(sbi->s_group_info);
if (old_groupinfo)
memcpy(new_groupinfo, old_groupinfo,
sbi->s_group_info_size * sizeof(*sbi->s_group_info));
rcu_read_unlock();
rcu_assign_pointer(sbi->s_group_info, new_groupinfo);
sbi->s_group_info_size = size / sizeof(*sbi->s_group_info);
if (old_groupinfo)
ext4_kvfree_array_rcu(old_groupinfo);
ext4_debug("allocated s_groupinfo array for %d meta_bg's\n",
sbi->s_group_info_size);
return 0;
}
/* Create and initialize ext4_group_info data for the given group. */
int ext4_mb_add_groupinfo(struct super_block *sb, ext4_group_t group,
struct ext4_group_desc *desc)
{
int i;
int metalen = 0;
int idx = group >> EXT4_DESC_PER_BLOCK_BITS(sb);
struct ext4_sb_info *sbi = EXT4_SB(sb);
struct ext4_group_info **meta_group_info;
struct kmem_cache *cachep = get_groupinfo_cache(sb->s_blocksize_bits);
/*
* First check if this group is the first of a reserved block.
* If it's true, we have to allocate a new table of pointers
* to ext4_group_info structures
*/
if (group % EXT4_DESC_PER_BLOCK(sb) == 0) {
metalen = sizeof(*meta_group_info) <<
EXT4_DESC_PER_BLOCK_BITS(sb);
meta_group_info = kmalloc(metalen, GFP_NOFS);
if (meta_group_info == NULL) {
ext4_msg(sb, KERN_ERR, "can't allocate mem "
"for a buddy group");
goto exit_meta_group_info;
}
rcu_read_lock();
rcu_dereference(sbi->s_group_info)[idx] = meta_group_info;
rcu_read_unlock();
}
meta_group_info = sbi_array_rcu_deref(sbi, s_group_info, idx);
i = group & (EXT4_DESC_PER_BLOCK(sb) - 1);
meta_group_info[i] = kmem_cache_zalloc(cachep, GFP_NOFS);
if (meta_group_info[i] == NULL) {
ext4_msg(sb, KERN_ERR, "can't allocate buddy mem");
goto exit_group_info;
}
set_bit(EXT4_GROUP_INFO_NEED_INIT_BIT,
&(meta_group_info[i]->bb_state));
/*
* initialize bb_free to be able to skip
* empty groups without initialization
*/
if (ext4_has_group_desc_csum(sb) &&
(desc->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT))) {
meta_group_info[i]->bb_free =
ext4_free_clusters_after_init(sb, group, desc);
} else {
meta_group_info[i]->bb_free =
ext4_free_group_clusters(sb, desc);
}
INIT_LIST_HEAD(&meta_group_info[i]->bb_prealloc_list);
init_rwsem(&meta_group_info[i]->alloc_sem);
meta_group_info[i]->bb_free_root = RB_ROOT;
INIT_LIST_HEAD(&meta_group_info[i]->bb_largest_free_order_node);
RB_CLEAR_NODE(&meta_group_info[i]->bb_avg_fragment_size_rb);
meta_group_info[i]->bb_largest_free_order = -1; /* uninit */
meta_group_info[i]->bb_group = group;
mb_group_bb_bitmap_alloc(sb, meta_group_info[i], group);
return 0;
exit_group_info:
/* If a meta_group_info table has been allocated, release it now */
if (group % EXT4_DESC_PER_BLOCK(sb) == 0) {
struct ext4_group_info ***group_info;
rcu_read_lock();
group_info = rcu_dereference(sbi->s_group_info);
kfree(group_info[idx]);
group_info[idx] = NULL;
rcu_read_unlock();
}
exit_meta_group_info:
return -ENOMEM;
} /* ext4_mb_add_groupinfo */
static int ext4_mb_init_backend(struct super_block *sb)
{
ext4_group_t ngroups = ext4_get_groups_count(sb);
ext4_group_t i;
struct ext4_sb_info *sbi = EXT4_SB(sb);
int err;
struct ext4_group_desc *desc;
struct ext4_group_info ***group_info;
struct kmem_cache *cachep;
err = ext4_mb_alloc_groupinfo(sb, ngroups);
if (err)
return err;
sbi->s_buddy_cache = new_inode(sb);
if (sbi->s_buddy_cache == NULL) {
ext4_msg(sb, KERN_ERR, "can't get new inode");
goto err_freesgi;
}
/* To avoid potentially colliding with an valid on-disk inode number,
* use EXT4_BAD_INO for the buddy cache inode number. This inode is
* not in the inode hash, so it should never be found by iget(), but
* this will avoid confusion if it ever shows up during debugging. */
sbi->s_buddy_cache->i_ino = EXT4_BAD_INO;
EXT4_I(sbi->s_buddy_cache)->i_disksize = 0;
for (i = 0; i < ngroups; i++) {
cond_resched();
desc = ext4_get_group_desc(sb, i, NULL);
if (desc == NULL) {
ext4_msg(sb, KERN_ERR, "can't read descriptor %u", i);
goto err_freebuddy;
}
if (ext4_mb_add_groupinfo(sb, i, desc) != 0)
goto err_freebuddy;
}
if (ext4_has_feature_flex_bg(sb)) {
/* a single flex group is supposed to be read by a single IO.
* 2 ^ s_log_groups_per_flex != UINT_MAX as s_mb_prefetch is
* unsigned integer, so the maximum shift is 32.
*/
if (sbi->s_es->s_log_groups_per_flex >= 32) {
ext4_msg(sb, KERN_ERR, "too many log groups per flexible block group");
goto err_freebuddy;
}
sbi->s_mb_prefetch = min_t(uint, 1 << sbi->s_es->s_log_groups_per_flex,
BLK_MAX_SEGMENT_SIZE >> (sb->s_blocksize_bits - 9));
sbi->s_mb_prefetch *= 8; /* 8 prefetch IOs in flight at most */
} else {
sbi->s_mb_prefetch = 32;
}
if (sbi->s_mb_prefetch > ext4_get_groups_count(sb))
sbi->s_mb_prefetch = ext4_get_groups_count(sb);
/* now many real IOs to prefetch within a single allocation at cr=0
* given cr=0 is an CPU-related optimization we shouldn't try to
* load too many groups, at some point we should start to use what
* we've got in memory.
* with an average random access time 5ms, it'd take a second to get
* 200 groups (* N with flex_bg), so let's make this limit 4
*/
sbi->s_mb_prefetch_limit = sbi->s_mb_prefetch * 4;
if (sbi->s_mb_prefetch_limit > ext4_get_groups_count(sb))
sbi->s_mb_prefetch_limit = ext4_get_groups_count(sb);
return 0;
err_freebuddy:
cachep = get_groupinfo_cache(sb->s_blocksize_bits);
while (i-- > 0)
kmem_cache_free(cachep, ext4_get_group_info(sb, i));
i = sbi->s_group_info_size;
rcu_read_lock();
group_info = rcu_dereference(sbi->s_group_info);
while (i-- > 0)
kfree(group_info[i]);
rcu_read_unlock();
iput(sbi->s_buddy_cache);
err_freesgi:
rcu_read_lock();
kvfree(rcu_dereference(sbi->s_group_info));
rcu_read_unlock();
return -ENOMEM;
}
static void ext4_groupinfo_destroy_slabs(void)
{
int i;
for (i = 0; i < NR_GRPINFO_CACHES; i++) {
kmem_cache_destroy(ext4_groupinfo_caches[i]);
ext4_groupinfo_caches[i] = NULL;
}
}
static int ext4_groupinfo_create_slab(size_t size)
{
static DEFINE_MUTEX(ext4_grpinfo_slab_create_mutex);
int slab_size;
int blocksize_bits = order_base_2(size);
int cache_index = blocksize_bits - EXT4_MIN_BLOCK_LOG_SIZE;
struct kmem_cache *cachep;
if (cache_index >= NR_GRPINFO_CACHES)
return -EINVAL;
if (unlikely(cache_index < 0))
cache_index = 0;
mutex_lock(&ext4_grpinfo_slab_create_mutex);
if (ext4_groupinfo_caches[cache_index]) {
mutex_unlock(&ext4_grpinfo_slab_create_mutex);
return 0; /* Already created */
}
slab_size = offsetof(struct ext4_group_info,
bb_counters[blocksize_bits + 2]);
cachep = kmem_cache_create(ext4_groupinfo_slab_names[cache_index],
slab_size, 0, SLAB_RECLAIM_ACCOUNT,
NULL);
ext4_groupinfo_caches[cache_index] = cachep;
mutex_unlock(&ext4_grpinfo_slab_create_mutex);
if (!cachep) {
printk(KERN_EMERG
"EXT4-fs: no memory for groupinfo slab cache\n");
return -ENOMEM;
}
return 0;
}
static void ext4_discard_work(struct work_struct *work)
{
struct ext4_sb_info *sbi = container_of(work,
struct ext4_sb_info, s_discard_work);
struct super_block *sb = sbi->s_sb;
struct ext4_free_data *fd, *nfd;
struct ext4_buddy e4b;
struct list_head discard_list;
ext4_group_t grp, load_grp;
int err = 0;
INIT_LIST_HEAD(&discard_list);
spin_lock(&sbi->s_md_lock);
list_splice_init(&sbi->s_discard_list, &discard_list);
spin_unlock(&sbi->s_md_lock);
load_grp = UINT_MAX;
list_for_each_entry_safe(fd, nfd, &discard_list, efd_list) {
/*
* If filesystem is umounting or no memory or suffering
* from no space, give up the discard
*/
if ((sb->s_flags & SB_ACTIVE) && !err &&
!atomic_read(&sbi->s_retry_alloc_pending)) {
grp = fd->efd_group;
if (grp != load_grp) {
if (load_grp != UINT_MAX)
ext4_mb_unload_buddy(&e4b);
err = ext4_mb_load_buddy(sb, grp, &e4b);
if (err) {
kmem_cache_free(ext4_free_data_cachep, fd);
load_grp = UINT_MAX;
continue;
} else {
load_grp = grp;
}
}
ext4_lock_group(sb, grp);
ext4_try_to_trim_range(sb, &e4b, fd->efd_start_cluster,
fd->efd_start_cluster + fd->efd_count - 1, 1);
ext4_unlock_group(sb, grp);
}
kmem_cache_free(ext4_free_data_cachep, fd);
}
if (load_grp != UINT_MAX)
ext4_mb_unload_buddy(&e4b);
}
int ext4_mb_init(struct super_block *sb)
{
struct ext4_sb_info *sbi = EXT4_SB(sb);
unsigned i, j;
unsigned offset, offset_incr;
unsigned max;
int ret;
i = MB_NUM_ORDERS(sb) * sizeof(*sbi->s_mb_offsets);
sbi->s_mb_offsets = kmalloc(i, GFP_KERNEL);
if (sbi->s_mb_offsets == NULL) {
ret = -ENOMEM;
goto out;
}
i = MB_NUM_ORDERS(sb) * sizeof(*sbi->s_mb_maxs);
sbi->s_mb_maxs = kmalloc(i, GFP_KERNEL);
if (sbi->s_mb_maxs == NULL) {
ret = -ENOMEM;
goto out;
}
ret = ext4_groupinfo_create_slab(sb->s_blocksize);
if (ret < 0)
goto out;
/* order 0 is regular bitmap */
sbi->s_mb_maxs[0] = sb->s_blocksize << 3;
sbi->s_mb_offsets[0] = 0;
i = 1;
offset = 0;
offset_incr = 1 << (sb->s_blocksize_bits - 1);
max = sb->s_blocksize << 2;
do {
sbi->s_mb_offsets[i] = offset;
sbi->s_mb_maxs[i] = max;
offset += offset_incr;
offset_incr = offset_incr >> 1;
max = max >> 1;
i++;
} while (i < MB_NUM_ORDERS(sb));
sbi->s_mb_avg_fragment_size_root = RB_ROOT;
sbi->s_mb_largest_free_orders =
kmalloc_array(MB_NUM_ORDERS(sb), sizeof(struct list_head),
GFP_KERNEL);
if (!sbi->s_mb_largest_free_orders) {
ret = -ENOMEM;
goto out;
}
sbi->s_mb_largest_free_orders_locks =
kmalloc_array(MB_NUM_ORDERS(sb), sizeof(rwlock_t),
GFP_KERNEL);
if (!sbi->s_mb_largest_free_orders_locks) {
ret = -ENOMEM;
goto out;
}
for (i = 0; i < MB_NUM_ORDERS(sb); i++) {
INIT_LIST_HEAD(&sbi->s_mb_largest_free_orders[i]);
rwlock_init(&sbi->s_mb_largest_free_orders_locks[i]);
}
rwlock_init(&sbi->s_mb_rb_lock);
spin_lock_init(&sbi->s_md_lock);
sbi->s_mb_free_pending = 0;
INIT_LIST_HEAD(&sbi->s_freed_data_list);
INIT_LIST_HEAD(&sbi->s_discard_list);
INIT_WORK(&sbi->s_discard_work, ext4_discard_work);
atomic_set(&sbi->s_retry_alloc_pending, 0);
sbi->s_mb_max_to_scan = MB_DEFAULT_MAX_TO_SCAN;
sbi->s_mb_min_to_scan = MB_DEFAULT_MIN_TO_SCAN;
sbi->s_mb_stats = MB_DEFAULT_STATS;
sbi->s_mb_stream_request = MB_DEFAULT_STREAM_THRESHOLD;
sbi->s_mb_order2_reqs = MB_DEFAULT_ORDER2_REQS;
sbi->s_mb_max_inode_prealloc = MB_DEFAULT_MAX_INODE_PREALLOC;
/*
* The default group preallocation is 512, which for 4k block
* sizes translates to 2 megabytes. However for bigalloc file
* systems, this is probably too big (i.e, if the cluster size
* is 1 megabyte, then group preallocation size becomes half a
* gigabyte!). As a default, we will keep a two megabyte
* group pralloc size for cluster sizes up to 64k, and after
* that, we will force a minimum group preallocation size of
* 32 clusters. This translates to 8 megs when the cluster
* size is 256k, and 32 megs when the cluster size is 1 meg,
* which seems reasonable as a default.
*/
sbi->s_mb_group_prealloc = max(MB_DEFAULT_GROUP_PREALLOC >>
sbi->s_cluster_bits, 32);
/*
* If there is a s_stripe > 1, then we set the s_mb_group_prealloc
* to the lowest multiple of s_stripe which is bigger than
* the s_mb_group_prealloc as determined above. We want
* the preallocation size to be an exact multiple of the
* RAID stripe size so that preallocations don't fragment
* the stripes.
*/
if (sbi->s_stripe > 1) {
sbi->s_mb_group_prealloc = roundup(
sbi->s_mb_group_prealloc, sbi->s_stripe);
}
sbi->s_locality_groups = alloc_percpu(struct ext4_locality_group);
if (sbi->s_locality_groups == NULL) {
ret = -ENOMEM;
goto out;
}
for_each_possible_cpu(i) {
struct ext4_locality_group *lg;
lg = per_cpu_ptr(sbi->s_locality_groups, i);
mutex_init(&lg->lg_mutex);
for (j = 0; j < PREALLOC_TB_SIZE; j++)
INIT_LIST_HEAD(&lg->lg_prealloc_list[j]);
spin_lock_init(&lg->lg_prealloc_lock);
}
if (blk_queue_nonrot(bdev_get_queue(sb->s_bdev)))
sbi->s_mb_max_linear_groups = 0;
else
sbi->s_mb_max_linear_groups = MB_DEFAULT_LINEAR_LIMIT;
/* init file for buddy data */
ret = ext4_mb_init_backend(sb);
if (ret != 0)
goto out_free_locality_groups;
return 0;
out_free_locality_groups:
free_percpu(sbi->s_locality_groups);
sbi->s_locality_groups = NULL;
out:
kfree(sbi->s_mb_largest_free_orders);
kfree(sbi->s_mb_largest_free_orders_locks);
kfree(sbi->s_mb_offsets);
sbi->s_mb_offsets = NULL;
kfree(sbi->s_mb_maxs);
sbi->s_mb_maxs = NULL;
return ret;
}
/* need to called with the ext4 group lock held */
static int ext4_mb_cleanup_pa(struct ext4_group_info *grp)
{
struct ext4_prealloc_space *pa;
struct list_head *cur, *tmp;
int count = 0;
list_for_each_safe(cur, tmp, &grp->bb_prealloc_list) {
pa = list_entry(cur, struct ext4_prealloc_space, pa_group_list);
list_del(&pa->pa_group_list);
count++;
kmem_cache_free(ext4_pspace_cachep, pa);
}
return count;
}
int ext4_mb_release(struct super_block *sb)
{
ext4_group_t ngroups = ext4_get_groups_count(sb);
ext4_group_t i;
int num_meta_group_infos;
struct ext4_group_info *grinfo, ***group_info;
struct ext4_sb_info *sbi = EXT4_SB(sb);
struct kmem_cache *cachep = get_groupinfo_cache(sb->s_blocksize_bits);
int count;
if (test_opt(sb, DISCARD)) {
/*
* wait the discard work to drain all of ext4_free_data
*/
flush_work(&sbi->s_discard_work);
WARN_ON_ONCE(!list_empty(&sbi->s_discard_list));
}
if (sbi->s_group_info) {
for (i = 0; i < ngroups; i++) {
cond_resched();
grinfo = ext4_get_group_info(sb, i);
mb_group_bb_bitmap_free(grinfo);
ext4_lock_group(sb, i);
count = ext4_mb_cleanup_pa(grinfo);
if (count)
mb_debug(sb, "mballoc: %d PAs left\n",
count);
ext4_unlock_group(sb, i);
kmem_cache_free(cachep, grinfo);
}
num_meta_group_infos = (ngroups +
EXT4_DESC_PER_BLOCK(sb) - 1) >>
EXT4_DESC_PER_BLOCK_BITS(sb);
rcu_read_lock();
group_info = rcu_dereference(sbi->s_group_info);
for (i = 0; i < num_meta_group_infos; i++)
kfree(group_info[i]);
kvfree(group_info);
rcu_read_unlock();
}
kfree(sbi->s_mb_largest_free_orders);
kfree(sbi->s_mb_largest_free_orders_locks);
kfree(sbi->s_mb_offsets);
kfree(sbi->s_mb_maxs);
iput(sbi->s_buddy_cache);
if (sbi->s_mb_stats) {
ext4_msg(sb, KERN_INFO,
"mballoc: %u blocks %u reqs (%u success)",
atomic_read(&sbi->s_bal_allocated),
atomic_read(&sbi->s_bal_reqs),
atomic_read(&sbi->s_bal_success));
ext4_msg(sb, KERN_INFO,
"mballoc: %u extents scanned, %u groups scanned, %u goal hits, "
"%u 2^N hits, %u breaks, %u lost",
atomic_read(&sbi->s_bal_ex_scanned),
atomic_read(&sbi->s_bal_groups_scanned),
atomic_read(&sbi->s_bal_goals),
atomic_read(&sbi->s_bal_2orders),
atomic_read(&sbi->s_bal_breaks),
atomic_read(&sbi->s_mb_lost_chunks));
ext4_msg(sb, KERN_INFO,
"mballoc: %u generated and it took %llu",
atomic_read(&sbi->s_mb_buddies_generated),
atomic64_read(&sbi->s_mb_generation_time));
ext4_msg(sb, KERN_INFO,
"mballoc: %u preallocated, %u discarded",
atomic_read(&sbi->s_mb_preallocated),
atomic_read(&sbi->s_mb_discarded));
}
free_percpu(sbi->s_locality_groups);
return 0;
}
static inline int ext4_issue_discard(struct super_block *sb,
ext4_group_t block_group, ext4_grpblk_t cluster, int count,
struct bio **biop)
{
ext4_fsblk_t discard_block;
discard_block = (EXT4_C2B(EXT4_SB(sb), cluster) +
ext4_group_first_block_no(sb, block_group));
count = EXT4_C2B(EXT4_SB(sb), count);
trace_ext4_discard_blocks(sb,
(unsigned long long) discard_block, count);
if (biop) {
return __blkdev_issue_discard(sb->s_bdev,
(sector_t)discard_block << (sb->s_blocksize_bits - 9),
(sector_t)count << (sb->s_blocksize_bits - 9),
GFP_NOFS, 0, biop);
} else
return sb_issue_discard(sb, discard_block, count, GFP_NOFS, 0);
}
static void ext4_free_data_in_buddy(struct super_block *sb,
struct ext4_free_data *entry)
{
struct ext4_buddy e4b;
struct ext4_group_info *db;
int err, count = 0, count2 = 0;
mb_debug(sb, "gonna free %u blocks in group %u (0x%p):",
entry->efd_count, entry->efd_group, entry);
err = ext4_mb_load_buddy(sb, entry->efd_group, &e4b);
/* we expect to find existing buddy because it's pinned */
BUG_ON(err != 0);
spin_lock(&EXT4_SB(sb)->s_md_lock);
EXT4_SB(sb)->s_mb_free_pending -= entry->efd_count;
spin_unlock(&EXT4_SB(sb)->s_md_lock);
db = e4b.bd_info;
/* there are blocks to put in buddy to make them really free */
count += entry->efd_count;
count2++;
ext4_lock_group(sb, entry->efd_group);
/* Take it out of per group rb tree */
rb_erase(&entry->efd_node, &(db->bb_free_root));
mb_free_blocks(NULL, &e4b, entry->efd_start_cluster, entry->efd_count);
/*
* Clear the trimmed flag for the group so that the next
* ext4_trim_fs can trim it.
* If the volume is mounted with -o discard, online discard
* is supported and the free blocks will be trimmed online.
*/
if (!test_opt(sb, DISCARD))
EXT4_MB_GRP_CLEAR_TRIMMED(db);
if (!db->bb_free_root.rb_node) {
/* No more items in the per group rb tree
* balance refcounts from ext4_mb_free_metadata()
*/
put_page(e4b.bd_buddy_page);
put_page(e4b.bd_bitmap_page);
}
ext4_unlock_group(sb, entry->efd_group);
ext4_mb_unload_buddy(&e4b);
mb_debug(sb, "freed %d blocks in %d structures\n", count,
count2);
}
/*
* This function is called by the jbd2 layer once the commit has finished,
* so we know we can free the blocks that were released with that commit.
*/
void ext4_process_freed_data(struct super_block *sb, tid_t commit_tid)
{
struct ext4_sb_info *sbi = EXT4_SB(sb);
struct ext4_free_data *entry, *tmp;
struct list_head freed_data_list;
struct list_head *cut_pos = NULL;
bool wake;
INIT_LIST_HEAD(&freed_data_list);
spin_lock(&sbi->s_md_lock);
list_for_each_entry(entry, &sbi->s_freed_data_list, efd_list) {
if (entry->efd_tid != commit_tid)
break;
cut_pos = &entry->efd_list;
}
if (cut_pos)
list_cut_position(&freed_data_list, &sbi->s_freed_data_list,
cut_pos);
spin_unlock(&sbi->s_md_lock);
list_for_each_entry(entry, &freed_data_list, efd_list)
ext4_free_data_in_buddy(sb, entry);
if (test_opt(sb, DISCARD)) {
spin_lock(&sbi->s_md_lock);
wake = list_empty(&sbi->s_discard_list);
list_splice_tail(&freed_data_list, &sbi->s_discard_list);
spin_unlock(&sbi->s_md_lock);
if (wake)
queue_work(system_unbound_wq, &sbi->s_discard_work);
} else {
list_for_each_entry_safe(entry, tmp, &freed_data_list, efd_list)
kmem_cache_free(ext4_free_data_cachep, entry);
}
}
int __init ext4_init_mballoc(void)
{
ext4_pspace_cachep = KMEM_CACHE(ext4_prealloc_space,
SLAB_RECLAIM_ACCOUNT);
if (ext4_pspace_cachep == NULL)
goto out;
ext4_ac_cachep = KMEM_CACHE(ext4_allocation_context,
SLAB_RECLAIM_ACCOUNT);
if (ext4_ac_cachep == NULL)
goto out_pa_free;
ext4_free_data_cachep = KMEM_CACHE(ext4_free_data,
SLAB_RECLAIM_ACCOUNT);
if (ext4_free_data_cachep == NULL)
goto out_ac_free;
return 0;
out_ac_free:
kmem_cache_destroy(ext4_ac_cachep);
out_pa_free:
kmem_cache_destroy(ext4_pspace_cachep);
out:
return -ENOMEM;
}
void ext4_exit_mballoc(void)
{
/*
* Wait for completion of call_rcu()'s on ext4_pspace_cachep
* before destroying the slab cache.
*/
rcu_barrier();
kmem_cache_destroy(ext4_pspace_cachep);
kmem_cache_destroy(ext4_ac_cachep);
kmem_cache_destroy(ext4_free_data_cachep);
ext4_groupinfo_destroy_slabs();
}
/*
* Check quota and mark chosen space (ac->ac_b_ex) non-free in bitmaps
* Returns 0 if success or error code
*/
static noinline_for_stack int
ext4_mb_mark_diskspace_used(struct ext4_allocation_context *ac,
handle_t *handle, unsigned int reserv_clstrs)
{
struct buffer_head *bitmap_bh = NULL;
struct ext4_group_desc *gdp;
struct buffer_head *gdp_bh;
struct ext4_sb_info *sbi;
struct super_block *sb;
ext4_fsblk_t block;
int err, len;
BUG_ON(ac->ac_status != AC_STATUS_FOUND);
BUG_ON(ac->ac_b_ex.fe_len <= 0);
sb = ac->ac_sb;
sbi = EXT4_SB(sb);
bitmap_bh = ext4_read_block_bitmap(sb, ac->ac_b_ex.fe_group);
if (IS_ERR(bitmap_bh)) {
err = PTR_ERR(bitmap_bh);
bitmap_bh = NULL;
goto out_err;
}
BUFFER_TRACE(bitmap_bh, "getting write access");
err = ext4_journal_get_write_access(handle, sb, bitmap_bh,
EXT4_JTR_NONE);
if (err)
goto out_err;
err = -EIO;
gdp = ext4_get_group_desc(sb, ac->ac_b_ex.fe_group, &gdp_bh);
if (!gdp)
goto out_err;
ext4_debug("using block group %u(%d)\n", ac->ac_b_ex.fe_group,
ext4_free_group_clusters(sb, gdp));
BUFFER_TRACE(gdp_bh, "get_write_access");
err = ext4_journal_get_write_access(handle, sb, gdp_bh, EXT4_JTR_NONE);
if (err)
goto out_err;
block = ext4_grp_offs_to_block(sb, &ac->ac_b_ex);
len = EXT4_C2B(sbi, ac->ac_b_ex.fe_len);
if (!ext4_inode_block_valid(ac->ac_inode, block, len)) {
ext4_error(sb, "Allocating blocks %llu-%llu which overlap "
"fs metadata", block, block+len);
/* File system mounted not to panic on error
* Fix the bitmap and return EFSCORRUPTED
* We leak some of the blocks here.
*/
ext4_lock_group(sb, ac->ac_b_ex.fe_group);
ext4_set_bits(bitmap_bh->b_data, ac->ac_b_ex.fe_start,
ac->ac_b_ex.fe_len);
ext4_unlock_group(sb, ac->ac_b_ex.fe_group);
err = ext4_handle_dirty_metadata(handle, NULL, bitmap_bh);
if (!err)
err = -EFSCORRUPTED;
goto out_err;
}
ext4_lock_group(sb, ac->ac_b_ex.fe_group);
#ifdef AGGRESSIVE_CHECK
{
int i;
for (i = 0; i < ac->ac_b_ex.fe_len; i++) {
BUG_ON(mb_test_bit(ac->ac_b_ex.fe_start + i,
bitmap_bh->b_data));
}
}
#endif
ext4_set_bits(bitmap_bh->b_data, ac->ac_b_ex.fe_start,
ac->ac_b_ex.fe_len);
if (ext4_has_group_desc_csum(sb) &&
(gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT))) {
gdp->bg_flags &= cpu_to_le16(~EXT4_BG_BLOCK_UNINIT);
ext4_free_group_clusters_set(sb, gdp,
ext4_free_clusters_after_init(sb,
ac->ac_b_ex.fe_group, gdp));
}
len = ext4_free_group_clusters(sb, gdp) - ac->ac_b_ex.fe_len;
ext4_free_group_clusters_set(sb, gdp, len);
ext4_block_bitmap_csum_set(sb, ac->ac_b_ex.fe_group, gdp, bitmap_bh);
ext4_group_desc_csum_set(sb, ac->ac_b_ex.fe_group, gdp);
ext4_unlock_group(sb, ac->ac_b_ex.fe_group);
percpu_counter_sub(&sbi->s_freeclusters_counter, ac->ac_b_ex.fe_len);
/*
* Now reduce the dirty block count also. Should not go negative
*/
if (!(ac->ac_flags & EXT4_MB_DELALLOC_RESERVED))
/* release all the reserved blocks if non delalloc */
percpu_counter_sub(&sbi->s_dirtyclusters_counter,
reserv_clstrs);
if (sbi->s_log_groups_per_flex) {
ext4_group_t flex_group = ext4_flex_group(sbi,
ac->ac_b_ex.fe_group);
atomic64_sub(ac->ac_b_ex.fe_len,
&sbi_array_rcu_deref(sbi, s_flex_groups,
flex_group)->free_clusters);
}
err = ext4_handle_dirty_metadata(handle, NULL, bitmap_bh);
if (err)
goto out_err;
err = ext4_handle_dirty_metadata(handle, NULL, gdp_bh);
out_err:
brelse(bitmap_bh);
return err;
}
/*
* Idempotent helper for Ext4 fast commit replay path to set the state of
* blocks in bitmaps and update counters.
*/
void ext4_mb_mark_bb(struct super_block *sb, ext4_fsblk_t block,
int len, int state)
{
struct buffer_head *bitmap_bh = NULL;
struct ext4_group_desc *gdp;
struct buffer_head *gdp_bh;
struct ext4_sb_info *sbi = EXT4_SB(sb);
ext4_group_t group;
ext4_grpblk_t blkoff;
int i, clen, err;
int already;
clen = EXT4_B2C(sbi, len);
ext4_get_group_no_and_offset(sb, block, &group, &blkoff);
bitmap_bh = ext4_read_block_bitmap(sb, group);
if (IS_ERR(bitmap_bh)) {
err = PTR_ERR(bitmap_bh);
bitmap_bh = NULL;
goto out_err;
}
err = -EIO;
gdp = ext4_get_group_desc(sb, group, &gdp_bh);
if (!gdp)
goto out_err;
ext4_lock_group(sb, group);
already = 0;
for (i = 0; i < clen; i++)
if (!mb_test_bit(blkoff + i, bitmap_bh->b_data) == !state)
already++;
if (state)
ext4_set_bits(bitmap_bh->b_data, blkoff, clen);
else
mb_test_and_clear_bits(bitmap_bh->b_data, blkoff, clen);
if (ext4_has_group_desc_csum(sb) &&
(gdp->bg_flags & cpu_to_le16(EXT4_BG_BLOCK_UNINIT))) {
gdp->bg_flags &= cpu_to_le16(~EXT4_BG_BLOCK_UNINIT);
ext4_free_group_clusters_set(sb, gdp,
ext4_free_clusters_after_init(sb,
group, gdp));
}
if (state)
clen = ext4_free_group_clusters(sb, gdp) - clen + already;
else
clen = ext4_free_group_clusters(sb, gdp) + clen - already;
ext4_free_group_clusters_set(sb, gdp, clen);
ext4_block_bitmap_csum_set(sb, group, gdp, bitmap_bh);
ext4_group_desc_csum_set(sb, group, gdp);
ext4_unlock_group(sb, group);
if (sbi->s_log_groups_per_flex) {
ext4_group_t flex_group = ext4_flex_group(sbi, group);
atomic64_sub(len,
&sbi_array_rcu_deref(sbi, s_flex_groups,
flex_group)->free_clusters);
}
err = ext4_handle_dirty_metadata(NULL, NULL, bitmap_bh);
if (err)
goto out_err;
sync_dirty_buffer(bitmap_bh);
err = ext4_handle_dirty_metadata(NULL, NULL, gdp_bh);
sync_dirty_buffer(gdp_bh);
out_err:
brelse(bitmap_bh);
}
/*
* here we normalize request for locality group
* Group request are normalized to s_mb_group_prealloc, which goes to
* s_strip if we set the same via mount option.
* s_mb_group_prealloc can be configured via
* /sys/fs/ext4/<partition>/mb_group_prealloc
*
* XXX: should we try to preallocate more than the group has now?
*/
static void ext4_mb_normalize_group_request(struct ext4_allocation_context *ac)
{
struct super_block *sb = ac->ac_sb;
struct ext4_locality_group *lg = ac->ac_lg;
BUG_ON(lg == NULL);
ac->ac_g_ex.fe_len = EXT4_SB(sb)->s_mb_group_prealloc;
mb_debug(sb, "goal %u blocks for locality group\n", ac->ac_g_ex.fe_len);
}
/*
* Normalization means making request better in terms of
* size and alignment
*/
static noinline_for_stack void
ext4_mb_normalize_request(struct ext4_allocation_context *ac,
struct ext4_allocation_request *ar)
{
struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
int bsbits, max;
ext4_lblk_t end;
loff_t size, start_off;
loff_t orig_size __maybe_unused;
ext4_lblk_t start;
struct ext4_inode_info *ei = EXT4_I(ac->ac_inode);
struct ext4_prealloc_space *pa;
/* do normalize only data requests, metadata requests
do not need preallocation */
if (!(ac->ac_flags & EXT4_MB_HINT_DATA))
return;
/* sometime caller may want exact blocks */
if (unlikely(ac->ac_flags & EXT4_MB_HINT_GOAL_ONLY))
return;
/* caller may indicate that preallocation isn't
* required (it's a tail, for example) */
if (ac->ac_flags & EXT4_MB_HINT_NOPREALLOC)
return;
if (ac->ac_flags & EXT4_MB_HINT_GROUP_ALLOC) {
ext4_mb_normalize_group_request(ac);
return ;
}
bsbits = ac->ac_sb->s_blocksize_bits;
/* first, let's learn actual file size
* given current request is allocated */
size = ac->ac_o_ex.fe_logical + EXT4_C2B(sbi, ac->ac_o_ex.fe_len);
size = size << bsbits;
if (size < i_size_read(ac->ac_inode))
size = i_size_read(ac->ac_inode);
orig_size = size;
/* max size of free chunks */
max = 2 << bsbits;
#define NRL_CHECK_SIZE(req, size, max, chunk_size) \
(req <= (size) || max <= (chunk_size))
/* first, try to predict filesize */
/* XXX: should this table be tunable? */
start_off = 0;
if (size <= 16 * 1024) {
size = 16 * 1024;
} else if (size <= 32 * 1024) {
size = 32 * 1024;
} else if (size <= 64 * 1024) {
size = 64 * 1024;
} else if (size <= 128 * 1024) {
size = 128 * 1024;
} else if (size <= 256 * 1024) {
size = 256 * 1024;
} else if (size <= 512 * 1024) {
size = 512 * 1024;
} else if (size <= 1024 * 1024) {
size = 1024 * 1024;
} else if (NRL_CHECK_SIZE(size, 4 * 1024 * 1024, max, 2 * 1024)) {
start_off = ((loff_t)ac->ac_o_ex.fe_logical >>
(21 - bsbits)) << 21;
size = 2 * 1024 * 1024;
} else if (NRL_CHECK_SIZE(size, 8 * 1024 * 1024, max, 4 * 1024)) {
start_off = ((loff_t)ac->ac_o_ex.fe_logical >>
(22 - bsbits)) << 22;
size = 4 * 1024 * 1024;
} else if (NRL_CHECK_SIZE(ac->ac_o_ex.fe_len,
(8<<20)>>bsbits, max, 8 * 1024)) {
start_off = ((loff_t)ac->ac_o_ex.fe_logical >>
(23 - bsbits)) << 23;
size = 8 * 1024 * 1024;
} else {
start_off = (loff_t) ac->ac_o_ex.fe_logical << bsbits;
size = (loff_t) EXT4_C2B(EXT4_SB(ac->ac_sb),
ac->ac_o_ex.fe_len) << bsbits;
}
size = size >> bsbits;
start = start_off >> bsbits;
/* don't cover already allocated blocks in selected range */
if (ar->pleft && start <= ar->lleft) {
size -= ar->lleft + 1 - start;
start = ar->lleft + 1;
}
if (ar->pright && start + size - 1 >= ar->lright)
size -= start + size - ar->lright;
/*
* Trim allocation request for filesystems with artificially small
* groups.
*/
if (size > EXT4_BLOCKS_PER_GROUP(ac->ac_sb))
size = EXT4_BLOCKS_PER_GROUP(ac->ac_sb);
end = start + size;
/* check we don't cross already preallocated blocks */
rcu_read_lock();
list_for_each_entry_rcu(pa, &ei->i_prealloc_list, pa_inode_list) {
ext4_lblk_t pa_end;
if (pa->pa_deleted)
continue;
spin_lock(&pa->pa_lock);
if (pa->pa_deleted) {
spin_unlock(&pa->pa_lock);
continue;
}
pa_end = pa->pa_lstart + EXT4_C2B(EXT4_SB(ac->ac_sb),
pa->pa_len);
/* PA must not overlap original request */
BUG_ON(!(ac->ac_o_ex.fe_logical >= pa_end ||
ac->ac_o_ex.fe_logical < pa->pa_lstart));
/* skip PAs this normalized request doesn't overlap with */
if (pa->pa_lstart >= end || pa_end <= start) {
spin_unlock(&pa->pa_lock);
continue;
}
BUG_ON(pa->pa_lstart <= start && pa_end >= end);
/* adjust start or end to be adjacent to this pa */
if (pa_end <= ac->ac_o_ex.fe_logical) {
BUG_ON(pa_end < start);
start = pa_end;
} else if (pa->pa_lstart > ac->ac_o_ex.fe_logical) {
BUG_ON(pa->pa_lstart > end);
end = pa->pa_lstart;
}
spin_unlock(&pa->pa_lock);
}
rcu_read_unlock();
size = end - start;
/* XXX: extra loop to check we really don't overlap preallocations */
rcu_read_lock();
list_for_each_entry_rcu(pa, &ei->i_prealloc_list, pa_inode_list) {
ext4_lblk_t pa_end;
spin_lock(&pa->pa_lock);
if (pa->pa_deleted == 0) {
pa_end = pa->pa_lstart + EXT4_C2B(EXT4_SB(ac->ac_sb),
pa->pa_len);
BUG_ON(!(start >= pa_end || end <= pa->pa_lstart));
}
spin_unlock(&pa->pa_lock);
}
rcu_read_unlock();
if (start + size <= ac->ac_o_ex.fe_logical &&
start > ac->ac_o_ex.fe_logical) {
ext4_msg(ac->ac_sb, KERN_ERR,
"start %lu, size %lu, fe_logical %lu",
(unsigned long) start, (unsigned long) size,
(unsigned long) ac->ac_o_ex.fe_logical);
BUG();
}
BUG_ON(size <= 0 || size > EXT4_BLOCKS_PER_GROUP(ac->ac_sb));
/* now prepare goal request */
/* XXX: is it better to align blocks WRT to logical
* placement or satisfy big request as is */
ac->ac_g_ex.fe_logical = start;
ac->ac_g_ex.fe_len = EXT4_NUM_B2C(sbi, size);
/* define goal start in order to merge */
if (ar->pright && (ar->lright == (start + size))) {
/* merge to the right */
ext4_get_group_no_and_offset(ac->ac_sb, ar->pright - size,
&ac->ac_f_ex.fe_group,
&ac->ac_f_ex.fe_start);
ac->ac_flags |= EXT4_MB_HINT_TRY_GOAL;
}
if (ar->pleft && (ar->lleft + 1 == start)) {
/* merge to the left */
ext4_get_group_no_and_offset(ac->ac_sb, ar->pleft + 1,
&ac->ac_f_ex.fe_group,
&ac->ac_f_ex.fe_start);
ac->ac_flags |= EXT4_MB_HINT_TRY_GOAL;
}
mb_debug(ac->ac_sb, "goal: %lld(was %lld) blocks at %u\n", size,
orig_size, start);
}
static void ext4_mb_collect_stats(struct ext4_allocation_context *ac)
{
struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
if (sbi->s_mb_stats && ac->ac_g_ex.fe_len >= 1) {
atomic_inc(&sbi->s_bal_reqs);
atomic_add(ac->ac_b_ex.fe_len, &sbi->s_bal_allocated);
if (ac->ac_b_ex.fe_len >= ac->ac_o_ex.fe_len)
atomic_inc(&sbi->s_bal_success);
atomic_add(ac->ac_found, &sbi->s_bal_ex_scanned);
atomic_add(ac->ac_groups_scanned, &sbi->s_bal_groups_scanned);
if (ac->ac_g_ex.fe_start == ac->ac_b_ex.fe_start &&
ac->ac_g_ex.fe_group == ac->ac_b_ex.fe_group)
atomic_inc(&sbi->s_bal_goals);
if (ac->ac_found > sbi->s_mb_max_to_scan)
atomic_inc(&sbi->s_bal_breaks);
}
if (ac->ac_op == EXT4_MB_HISTORY_ALLOC)
trace_ext4_mballoc_alloc(ac);
else
trace_ext4_mballoc_prealloc(ac);
}
/*
* Called on failure; free up any blocks from the inode PA for this
* context. We don't need this for MB_GROUP_PA because we only change
* pa_free in ext4_mb_release_context(), but on failure, we've already
* zeroed out ac->ac_b_ex.fe_len, so group_pa->pa_free is not changed.
*/
static void ext4_discard_allocated_blocks(struct ext4_allocation_context *ac)
{
struct ext4_prealloc_space *pa = ac->ac_pa;
struct ext4_buddy e4b;
int err;
if (pa == NULL) {
if (ac->ac_f_ex.fe_len == 0)
return;
err = ext4_mb_load_buddy(ac->ac_sb, ac->ac_f_ex.fe_group, &e4b);
if (err) {
/*
* This should never happen since we pin the
* pages in the ext4_allocation_context so
* ext4_mb_load_buddy() should never fail.
*/
WARN(1, "mb_load_buddy failed (%d)", err);
return;
}
ext4_lock_group(ac->ac_sb, ac->ac_f_ex.fe_group);
mb_free_blocks(ac->ac_inode, &e4b, ac->ac_f_ex.fe_start,
ac->ac_f_ex.fe_len);
ext4_unlock_group(ac->ac_sb, ac->ac_f_ex.fe_group);
ext4_mb_unload_buddy(&e4b);
return;
}
if (pa->pa_type == MB_INODE_PA)
pa->pa_free += ac->ac_b_ex.fe_len;
}
/*
* use blocks preallocated to inode
*/
static void ext4_mb_use_inode_pa(struct ext4_allocation_context *ac,
struct ext4_prealloc_space *pa)
{
struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
ext4_fsblk_t start;
ext4_fsblk_t end;
int len;
/* found preallocated blocks, use them */
start = pa->pa_pstart + (ac->ac_o_ex.fe_logical - pa->pa_lstart);
end = min(pa->pa_pstart + EXT4_C2B(sbi, pa->pa_len),
start + EXT4_C2B(sbi, ac->ac_o_ex.fe_len));
len = EXT4_NUM_B2C(sbi, end - start);
ext4_get_group_no_and_offset(ac->ac_sb, start, &ac->ac_b_ex.fe_group,
&ac->ac_b_ex.fe_start);
ac->ac_b_ex.fe_len = len;
ac->ac_status = AC_STATUS_FOUND;
ac->ac_pa = pa;
BUG_ON(start < pa->pa_pstart);
BUG_ON(end > pa->pa_pstart + EXT4_C2B(sbi, pa->pa_len));
BUG_ON(pa->pa_free < len);
pa->pa_free -= len;
mb_debug(ac->ac_sb, "use %llu/%d from inode pa %p\n", start, len, pa);
}
/*
* use blocks preallocated to locality group
*/
static void ext4_mb_use_group_pa(struct ext4_allocation_context *ac,
struct ext4_prealloc_space *pa)
{
unsigned int len = ac->ac_o_ex.fe_len;
ext4_get_group_no_and_offset(ac->ac_sb, pa->pa_pstart,
&ac->ac_b_ex.fe_group,
&ac->ac_b_ex.fe_start);
ac->ac_b_ex.fe_len = len;
ac->ac_status = AC_STATUS_FOUND;
ac->ac_pa = pa;
/* we don't correct pa_pstart or pa_plen here to avoid
* possible race when the group is being loaded concurrently
* instead we correct pa later, after blocks are marked
* in on-disk bitmap -- see ext4_mb_release_context()
* Other CPUs are prevented from allocating from this pa by lg_mutex
*/
mb_debug(ac->ac_sb, "use %u/%u from group pa %p\n",
pa->pa_lstart-len, len, pa);
}
/*
* Return the prealloc space that have minimal distance
* from the goal block. @cpa is the prealloc
* space that is having currently known minimal distance
* from the goal block.
*/
static struct ext4_prealloc_space *
ext4_mb_check_group_pa(ext4_fsblk_t goal_block,
struct ext4_prealloc_space *pa,
struct ext4_prealloc_space *cpa)
{
ext4_fsblk_t cur_distance, new_distance;
if (cpa == NULL) {
atomic_inc(&pa->pa_count);
return pa;
}
cur_distance = abs(goal_block - cpa->pa_pstart);
new_distance = abs(goal_block - pa->pa_pstart);
if (cur_distance <= new_distance)
return cpa;
/* drop the previous reference */
atomic_dec(&cpa->pa_count);
atomic_inc(&pa->pa_count);
return pa;
}
/*
* search goal blocks in preallocated space
*/
static noinline_for_stack bool
ext4_mb_use_preallocated(struct ext4_allocation_context *ac)
{
struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
int order, i;
struct ext4_inode_info *ei = EXT4_I(ac->ac_inode);
struct ext4_locality_group *lg;
struct ext4_prealloc_space *pa, *cpa = NULL;
ext4_fsblk_t goal_block;
/* only data can be preallocated */
if (!(ac->ac_flags & EXT4_MB_HINT_DATA))
return false;
/* first, try per-file preallocation */
rcu_read_lock();
list_for_each_entry_rcu(pa, &ei->i_prealloc_list, pa_inode_list) {
/* all fields in this condition don't change,
* so we can skip locking for them */
if (ac->ac_o_ex.fe_logical < pa->pa_lstart ||
ac->ac_o_ex.fe_logical >= (pa->pa_lstart +
EXT4_C2B(sbi, pa->pa_len)))
continue;
/* non-extent files can't have physical blocks past 2^32 */
if (!(ext4_test_inode_flag(ac->ac_inode, EXT4_INODE_EXTENTS)) &&
(pa->pa_pstart + EXT4_C2B(sbi, pa->pa_len) >
EXT4_MAX_BLOCK_FILE_PHYS))
continue;
/* found preallocated blocks, use them */
spin_lock(&pa->pa_lock);
if (pa->pa_deleted == 0 && pa->pa_free) {
atomic_inc(&pa->pa_count);
ext4_mb_use_inode_pa(ac, pa);
spin_unlock(&pa->pa_lock);
ac->ac_criteria = 10;
rcu_read_unlock();
return true;
}
spin_unlock(&pa->pa_lock);
}
rcu_read_unlock();
/* can we use group allocation? */
if (!(ac->ac_flags & EXT4_MB_HINT_GROUP_ALLOC))
return false;
/* inode may have no locality group for some reason */
lg = ac->ac_lg;
if (lg == NULL)
return false;
order = fls(ac->ac_o_ex.fe_len) - 1;
if (order > PREALLOC_TB_SIZE - 1)
/* The max size of hash table is PREALLOC_TB_SIZE */
order = PREALLOC_TB_SIZE - 1;
goal_block = ext4_grp_offs_to_block(ac->ac_sb, &ac->ac_g_ex);
/*
* search for the prealloc space that is having
* minimal distance from the goal block.
*/
for (i = order; i < PREALLOC_TB_SIZE; i++) {
rcu_read_lock();
list_for_each_entry_rcu(pa, &lg->lg_prealloc_list[i],
pa_inode_list) {
spin_lock(&pa->pa_lock);
if (pa->pa_deleted == 0 &&
pa->pa_free >= ac->ac_o_ex.fe_len) {
cpa = ext4_mb_check_group_pa(goal_block,
pa, cpa);
}
spin_unlock(&pa->pa_lock);
}
rcu_read_unlock();
}
if (cpa) {
ext4_mb_use_group_pa(ac, cpa);
ac->ac_criteria = 20;
return true;
}
return false;
}
/*
* the function goes through all block freed in the group
* but not yet committed and marks them used in in-core bitmap.
* buddy must be generated from this bitmap
* Need to be called with the ext4 group lock held
*/
static void ext4_mb_generate_from_freelist(struct super_block *sb, void *bitmap,
ext4_group_t group)
{
struct rb_node *n;
struct ext4_group_info *grp;
struct ext4_free_data *entry;
grp = ext4_get_group_info(sb, group);
n = rb_first(&(grp->bb_free_root));
while (n) {
entry = rb_entry(n, struct ext4_free_data, efd_node);
ext4_set_bits(bitmap, entry->efd_start_cluster, entry->efd_count);
n = rb_next(n);
}
return;
}
/*
* the function goes through all preallocation in this group and marks them
* used in in-core bitmap. buddy must be generated from this bitmap
* Need to be called with ext4 group lock held
*/
static noinline_for_stack
void ext4_mb_generate_from_pa(struct super_block *sb, void *bitmap,
ext4_group_t group)
{
struct ext4_group_info *grp = ext4_get_group_info(sb, group);
struct ext4_prealloc_space *pa;
struct list_head *cur;
ext4_group_t groupnr;
ext4_grpblk_t start;
int preallocated = 0;
int len;
/* all form of preallocation discards first load group,
* so the only competing code is preallocation use.
* we don't need any locking here
* notice we do NOT ignore preallocations with pa_deleted
* otherwise we could leave used blocks available for
* allocation in buddy when concurrent ext4_mb_put_pa()
* is dropping preallocation
*/
list_for_each(cur, &grp->bb_prealloc_list) {
pa = list_entry(cur, struct ext4_prealloc_space, pa_group_list);
spin_lock(&pa->pa_lock);
ext4_get_group_no_and_offset(sb, pa->pa_pstart,
&groupnr, &start);
len = pa->pa_len;
spin_unlock(&pa->pa_lock);
if (unlikely(len == 0))
continue;
BUG_ON(groupnr != group);
ext4_set_bits(bitmap, start, len);
preallocated += len;
}
mb_debug(sb, "preallocated %d for group %u\n", preallocated, group);
}
static void ext4_mb_mark_pa_deleted(struct super_block *sb,
struct ext4_prealloc_space *pa)
{
struct ext4_inode_info *ei;
if (pa->pa_deleted) {
ext4_warning(sb, "deleted pa, type:%d, pblk:%llu, lblk:%u, len:%d\n",
pa->pa_type, pa->pa_pstart, pa->pa_lstart,
pa->pa_len);
return;
}
pa->pa_deleted = 1;
if (pa->pa_type == MB_INODE_PA) {
ei = EXT4_I(pa->pa_inode);
atomic_dec(&ei->i_prealloc_active);
}
}
static void ext4_mb_pa_callback(struct rcu_head *head)
{
struct ext4_prealloc_space *pa;
pa = container_of(head, struct ext4_prealloc_space, u.pa_rcu);
BUG_ON(atomic_read(&pa->pa_count));
BUG_ON(pa->pa_deleted == 0);
kmem_cache_free(ext4_pspace_cachep, pa);
}
/*
* drops a reference to preallocated space descriptor
* if this was the last reference and the space is consumed
*/
static void ext4_mb_put_pa(struct ext4_allocation_context *ac,
struct super_block *sb, struct ext4_prealloc_space *pa)
{
ext4_group_t grp;
ext4_fsblk_t grp_blk;
/* in this short window concurrent discard can set pa_deleted */
spin_lock(&pa->pa_lock);
if (!atomic_dec_and_test(&pa->pa_count) || pa->pa_free != 0) {
spin_unlock(&pa->pa_lock);
return;
}
if (pa->pa_deleted == 1) {
spin_unlock(&pa->pa_lock);
return;
}
ext4_mb_mark_pa_deleted(sb, pa);
spin_unlock(&pa->pa_lock);
grp_blk = pa->pa_pstart;
/*
* If doing group-based preallocation, pa_pstart may be in the
* next group when pa is used up
*/
if (pa->pa_type == MB_GROUP_PA)
grp_blk--;
grp = ext4_get_group_number(sb, grp_blk);
/*
* possible race:
*
* P1 (buddy init) P2 (regular allocation)
* find block B in PA
* copy on-disk bitmap to buddy
* mark B in on-disk bitmap
* drop PA from group
* mark all PAs in buddy
*
* thus, P1 initializes buddy with B available. to prevent this
* we make "copy" and "mark all PAs" atomic and serialize "drop PA"
* against that pair
*/
ext4_lock_group(sb, grp);
list_del(&pa->pa_group_list);
ext4_unlock_group(sb, grp);
spin_lock(pa->pa_obj_lock);
list_del_rcu(&pa->pa_inode_list);
spin_unlock(pa->pa_obj_lock);
call_rcu(&(pa)->u.pa_rcu, ext4_mb_pa_callback);
}
/*
* creates new preallocated space for given inode
*/
static noinline_for_stack void
ext4_mb_new_inode_pa(struct ext4_allocation_context *ac)
{
struct super_block *sb = ac->ac_sb;
struct ext4_sb_info *sbi = EXT4_SB(sb);
struct ext4_prealloc_space *pa;
struct ext4_group_info *grp;
struct ext4_inode_info *ei;
/* preallocate only when found space is larger then requested */
BUG_ON(ac->ac_o_ex.fe_len >= ac->ac_b_ex.fe_len);
BUG_ON(ac->ac_status != AC_STATUS_FOUND);
BUG_ON(!S_ISREG(ac->ac_inode->i_mode));
BUG_ON(ac->ac_pa == NULL);
pa = ac->ac_pa;
if (ac->ac_b_ex.fe_len < ac->ac_g_ex.fe_len) {
int winl;
int wins;
int win;
int offs;
/* we can't allocate as much as normalizer wants.
* so, found space must get proper lstart
* to cover original request */
BUG_ON(ac->ac_g_ex.fe_logical > ac->ac_o_ex.fe_logical);
BUG_ON(ac->ac_g_ex.fe_len < ac->ac_o_ex.fe_len);
/* we're limited by original request in that
* logical block must be covered any way
* winl is window we can move our chunk within */
winl = ac->ac_o_ex.fe_logical - ac->ac_g_ex.fe_logical;
/* also, we should cover whole original request */
wins = EXT4_C2B(sbi, ac->ac_b_ex.fe_len - ac->ac_o_ex.fe_len);
/* the smallest one defines real window */
win = min(winl, wins);
offs = ac->ac_o_ex.fe_logical %
EXT4_C2B(sbi, ac->ac_b_ex.fe_len);
if (offs && offs < win)
win = offs;
ac->ac_b_ex.fe_logical = ac->ac_o_ex.fe_logical -
EXT4_NUM_B2C(sbi, win);
BUG_ON(ac->ac_o_ex.fe_logical < ac->ac_b_ex.fe_logical);
BUG_ON(ac->ac_o_ex.fe_len > ac->ac_b_ex.fe_len);
}
/* preallocation can change ac_b_ex, thus we store actually
* allocated blocks for history */
ac->ac_f_ex = ac->ac_b_ex;
pa->pa_lstart = ac->ac_b_ex.fe_logical;
pa->pa_pstart = ext4_grp_offs_to_block(sb, &ac->ac_b_ex);
pa->pa_len = ac->ac_b_ex.fe_len;
pa->pa_free = pa->pa_len;
spin_lock_init(&pa->pa_lock);
INIT_LIST_HEAD(&pa->pa_inode_list);
INIT_LIST_HEAD(&pa->pa_group_list);
pa->pa_deleted = 0;
pa->pa_type = MB_INODE_PA;
mb_debug(sb, "new inode pa %p: %llu/%d for %u\n", pa, pa->pa_pstart,
pa->pa_len, pa->pa_lstart);
trace_ext4_mb_new_inode_pa(ac, pa);
ext4_mb_use_inode_pa(ac, pa);
atomic_add(pa->pa_free, &sbi->s_mb_preallocated);
ei = EXT4_I(ac->ac_inode);
grp = ext4_get_group_info(sb, ac->ac_b_ex.fe_group);
pa->pa_obj_lock = &ei->i_prealloc_lock;
pa->pa_inode = ac->ac_inode;
list_add(&pa->pa_group_list, &grp->bb_prealloc_list);
spin_lock(pa->pa_obj_lock);
list_add_rcu(&pa->pa_inode_list, &ei->i_prealloc_list);
spin_unlock(pa->pa_obj_lock);
atomic_inc(&ei->i_prealloc_active);
}
/*
* creates new preallocated space for locality group inodes belongs to
*/
static noinline_for_stack void
ext4_mb_new_group_pa(struct ext4_allocation_context *ac)
{
struct super_block *sb = ac->ac_sb;
struct ext4_locality_group *lg;
struct ext4_prealloc_space *pa;
struct ext4_group_info *grp;
/* preallocate only when found space is larger then requested */
BUG_ON(ac->ac_o_ex.fe_len >= ac->ac_b_ex.fe_len);
BUG_ON(ac->ac_status != AC_STATUS_FOUND);
BUG_ON(!S_ISREG(ac->ac_inode->i_mode));
BUG_ON(ac->ac_pa == NULL);
pa = ac->ac_pa;
/* preallocation can change ac_b_ex, thus we store actually
* allocated blocks for history */
ac->ac_f_ex = ac->ac_b_ex;
pa->pa_pstart = ext4_grp_offs_to_block(sb, &ac->ac_b_ex);
pa->pa_lstart = pa->pa_pstart;
pa->pa_len = ac->ac_b_ex.fe_len;
pa->pa_free = pa->pa_len;
spin_lock_init(&pa->pa_lock);
INIT_LIST_HEAD(&pa->pa_inode_list);
INIT_LIST_HEAD(&pa->pa_group_list);
pa->pa_deleted = 0;
pa->pa_type = MB_GROUP_PA;
mb_debug(sb, "new group pa %p: %llu/%d for %u\n", pa, pa->pa_pstart,
pa->pa_len, pa->pa_lstart);
trace_ext4_mb_new_group_pa(ac, pa);
ext4_mb_use_group_pa(ac, pa);
atomic_add(pa->pa_free, &EXT4_SB(sb)->s_mb_preallocated);
grp = ext4_get_group_info(sb, ac->ac_b_ex.fe_group);
lg = ac->ac_lg;
BUG_ON(lg == NULL);
pa->pa_obj_lock = &lg->lg_prealloc_lock;
pa->pa_inode = NULL;
list_add(&pa->pa_group_list, &grp->bb_prealloc_list);
/*
* We will later add the new pa to the right bucket
* after updating the pa_free in ext4_mb_release_context
*/
}
static void ext4_mb_new_preallocation(struct ext4_allocation_context *ac)
{
if (ac->ac_flags & EXT4_MB_HINT_GROUP_ALLOC)
ext4_mb_new_group_pa(ac);
else
ext4_mb_new_inode_pa(ac);
}
/*
* finds all unused blocks in on-disk bitmap, frees them in
* in-core bitmap and buddy.
* @pa must be unlinked from inode and group lists, so that
* nobody else can find/use it.
* the caller MUST hold group/inode locks.
* TODO: optimize the case when there are no in-core structures yet
*/
static noinline_for_stack int
ext4_mb_release_inode_pa(struct ext4_buddy *e4b, struct buffer_head *bitmap_bh,
struct ext4_prealloc_space *pa)
{
struct super_block *sb = e4b->bd_sb;
struct ext4_sb_info *sbi = EXT4_SB(sb);
unsigned int end;
unsigned int next;
ext4_group_t group;
ext4_grpblk_t bit;
unsigned long long grp_blk_start;
int free = 0;
BUG_ON(pa->pa_deleted == 0);
ext4_get_group_no_and_offset(sb, pa->pa_pstart, &group, &bit);
grp_blk_start = pa->pa_pstart - EXT4_C2B(sbi, bit);
BUG_ON(group != e4b->bd_group && pa->pa_len != 0);
end = bit + pa->pa_len;
while (bit < end) {
bit = mb_find_next_zero_bit(bitmap_bh->b_data, end, bit);
if (bit >= end)
break;
next = mb_find_next_bit(bitmap_bh->b_data, end, bit);
mb_debug(sb, "free preallocated %u/%u in group %u\n",
(unsigned) ext4_group_first_block_no(sb, group) + bit,
(unsigned) next - bit, (unsigned) group);
free += next - bit;
trace_ext4_mballoc_discard(sb, NULL, group, bit, next - bit);
trace_ext4_mb_release_inode_pa(pa, (grp_blk_start +
EXT4_C2B(sbi, bit)),
next - bit);
mb_free_blocks(pa->pa_inode, e4b, bit, next - bit);
bit = next + 1;
}
if (free != pa->pa_free) {
ext4_msg(e4b->bd_sb, KERN_CRIT,
"pa %p: logic %lu, phys. %lu, len %d",
pa, (unsigned long) pa->pa_lstart,
(unsigned long) pa->pa_pstart,
pa->pa_len);
ext4_grp_locked_error(sb, group, 0, 0, "free %u, pa_free %u",
free, pa->pa_free);
/*
* pa is already deleted so we use the value obtained
* from the bitmap and continue.
*/
}
atomic_add(free, &sbi->s_mb_discarded);
return 0;
}
static noinline_for_stack int
ext4_mb_release_group_pa(struct ext4_buddy *e4b,
struct ext4_prealloc_space *pa)
{
struct super_block *sb = e4b->bd_sb;
ext4_group_t group;
ext4_grpblk_t bit;
trace_ext4_mb_release_group_pa(sb, pa);
BUG_ON(pa->pa_deleted == 0);
ext4_get_group_no_and_offset(sb, pa->pa_pstart, &group, &bit);
BUG_ON(group != e4b->bd_group && pa->pa_len != 0);
mb_free_blocks(pa->pa_inode, e4b, bit, pa->pa_len);
atomic_add(pa->pa_len, &EXT4_SB(sb)->s_mb_discarded);
trace_ext4_mballoc_discard(sb, NULL, group, bit, pa->pa_len);
return 0;
}
/*
* releases all preallocations in given group
*
* first, we need to decide discard policy:
* - when do we discard
* 1) ENOSPC
* - how many do we discard
* 1) how many requested
*/
static noinline_for_stack int
ext4_mb_discard_group_preallocations(struct super_block *sb,
ext4_group_t group, int needed)
{
struct ext4_group_info *grp = ext4_get_group_info(sb, group);
struct buffer_head *bitmap_bh = NULL;
struct ext4_prealloc_space *pa, *tmp;
struct list_head list;
struct ext4_buddy e4b;
int err;
int busy = 0;
int free, free_total = 0;
mb_debug(sb, "discard preallocation for group %u\n", group);
if (list_empty(&grp->bb_prealloc_list))
goto out_dbg;
bitmap_bh = ext4_read_block_bitmap(sb, group);
if (IS_ERR(bitmap_bh)) {
err = PTR_ERR(bitmap_bh);
ext4_error_err(sb, -err,
"Error %d reading block bitmap for %u",
err, group);
goto out_dbg;
}
err = ext4_mb_load_buddy(sb, group, &e4b);
if (err) {
ext4_warning(sb, "Error %d loading buddy information for %u",
err, group);
put_bh(bitmap_bh);
goto out_dbg;
}
if (needed == 0)
needed = EXT4_CLUSTERS_PER_GROUP(sb) + 1;
INIT_LIST_HEAD(&list);
repeat:
free = 0;
ext4_lock_group(sb, group);
list_for_each_entry_safe(pa, tmp,
&grp->bb_prealloc_list, pa_group_list) {
spin_lock(&pa->pa_lock);
if (atomic_read(&pa->pa_count)) {
spin_unlock(&pa->pa_lock);
busy = 1;
continue;
}
if (pa->pa_deleted) {
spin_unlock(&pa->pa_lock);
continue;
}
/* seems this one can be freed ... */
ext4_mb_mark_pa_deleted(sb, pa);
if (!free)
this_cpu_inc(discard_pa_seq);
/* we can trust pa_free ... */
free += pa->pa_free;
spin_unlock(&pa->pa_lock);
list_del(&pa->pa_group_list);
list_add(&pa->u.pa_tmp_list, &list);
}
/* now free all selected PAs */
list_for_each_entry_safe(pa, tmp, &list, u.pa_tmp_list) {
/* remove from object (inode or locality group) */
spin_lock(pa->pa_obj_lock);
list_del_rcu(&pa->pa_inode_list);
spin_unlock(pa->pa_obj_lock);
if (pa->pa_type == MB_GROUP_PA)
ext4_mb_release_group_pa(&e4b, pa);
else
ext4_mb_release_inode_pa(&e4b, bitmap_bh, pa);
list_del(&pa->u.pa_tmp_list);
call_rcu(&(pa)->u.pa_rcu, ext4_mb_pa_callback);
}
free_total += free;
/* if we still need more blocks and some PAs were used, try again */
if (free_total < needed && busy) {
ext4_unlock_group(sb, group);
cond_resched();
busy = 0;
goto repeat;
}
ext4_unlock_group(sb, group);
ext4_mb_unload_buddy(&e4b);
put_bh(bitmap_bh);
out_dbg:
mb_debug(sb, "discarded (%d) blocks preallocated for group %u bb_free (%d)\n",
free_total, group, grp->bb_free);
return free_total;
}
/*
* releases all non-used preallocated blocks for given inode
*
* It's important to discard preallocations under i_data_sem
* We don't want another block to be served from the prealloc
* space when we are discarding the inode prealloc space.
*
* FIXME!! Make sure it is valid at all the call sites
*/
void ext4_discard_preallocations(struct inode *inode, unsigned int needed)
{
struct ext4_inode_info *ei = EXT4_I(inode);
struct super_block *sb = inode->i_sb;
struct buffer_head *bitmap_bh = NULL;
struct ext4_prealloc_space *pa, *tmp;
ext4_group_t group = 0;
struct list_head list;
struct ext4_buddy e4b;
int err;
if (!S_ISREG(inode->i_mode)) {
/*BUG_ON(!list_empty(&ei->i_prealloc_list));*/
return;
}
if (EXT4_SB(sb)->s_mount_state & EXT4_FC_REPLAY)
return;
mb_debug(sb, "discard preallocation for inode %lu\n",
inode->i_ino);
trace_ext4_discard_preallocations(inode,
atomic_read(&ei->i_prealloc_active), needed);
INIT_LIST_HEAD(&list);
if (needed == 0)
needed = UINT_MAX;
repeat:
/* first, collect all pa's in the inode */
spin_lock(&ei->i_prealloc_lock);
while (!list_empty(&ei->i_prealloc_list) && needed) {
pa = list_entry(ei->i_prealloc_list.prev,
struct ext4_prealloc_space, pa_inode_list);
BUG_ON(pa->pa_obj_lock != &ei->i_prealloc_lock);
spin_lock(&pa->pa_lock);
if (atomic_read(&pa->pa_count)) {
/* this shouldn't happen often - nobody should
* use preallocation while we're discarding it */
spin_unlock(&pa->pa_lock);
spin_unlock(&ei->i_prealloc_lock);
ext4_msg(sb, KERN_ERR,
"uh-oh! used pa while discarding");
WARN_ON(1);
schedule_timeout_uninterruptible(HZ);
goto repeat;
}
if (pa->pa_deleted == 0) {
ext4_mb_mark_pa_deleted(sb, pa);
spin_unlock(&pa->pa_lock);
list_del_rcu(&pa->pa_inode_list);
list_add(&pa->u.pa_tmp_list, &list);
needed--;
continue;
}
/* someone is deleting pa right now */
spin_unlock(&pa->pa_lock);
spin_unlock(&ei->i_prealloc_lock);
/* we have to wait here because pa_deleted
* doesn't mean pa is already unlinked from
* the list. as we might be called from
* ->clear_inode() the inode will get freed
* and concurrent thread which is unlinking
* pa from inode's list may access already
* freed memory, bad-bad-bad */
/* XXX: if this happens too often, we can
* add a flag to force wait only in case
* of ->clear_inode(), but not in case of
* regular truncate */
schedule_timeout_uninterruptible(HZ);
goto repeat;
}
spin_unlock(&ei->i_prealloc_lock);
list_for_each_entry_safe(pa, tmp, &list, u.pa_tmp_list) {
BUG_ON(pa->pa_type != MB_INODE_PA);
group = ext4_get_group_number(sb, pa->pa_pstart);
err = ext4_mb_load_buddy_gfp(sb, group, &e4b,
GFP_NOFS|__GFP_NOFAIL);
if (err) {
ext4_error_err(sb, -err, "Error %d loading buddy information for %u",
err, group);
continue;
}
bitmap_bh = ext4_read_block_bitmap(sb, group);
if (IS_ERR(bitmap_bh)) {
err = PTR_ERR(bitmap_bh);
ext4_error_err(sb, -err, "Error %d reading block bitmap for %u",
err, group);
ext4_mb_unload_buddy(&e4b);
continue;
}
ext4_lock_group(sb, group);
list_del(&pa->pa_group_list);
ext4_mb_release_inode_pa(&e4b, bitmap_bh, pa);
ext4_unlock_group(sb, group);
ext4_mb_unload_buddy(&e4b);
put_bh(bitmap_bh);
list_del(&pa->u.pa_tmp_list);
call_rcu(&(pa)->u.pa_rcu, ext4_mb_pa_callback);
}
}
static int ext4_mb_pa_alloc(struct ext4_allocation_context *ac)
{
struct ext4_prealloc_space *pa;
BUG_ON(ext4_pspace_cachep == NULL);
pa = kmem_cache_zalloc(ext4_pspace_cachep, GFP_NOFS);
if (!pa)
return -ENOMEM;
atomic_set(&pa->pa_count, 1);
ac->ac_pa = pa;
return 0;
}
static void ext4_mb_pa_free(struct ext4_allocation_context *ac)
{
struct ext4_prealloc_space *pa = ac->ac_pa;
BUG_ON(!pa);
ac->ac_pa = NULL;
WARN_ON(!atomic_dec_and_test(&pa->pa_count));
kmem_cache_free(ext4_pspace_cachep, pa);
}
#ifdef CONFIG_EXT4_DEBUG
static inline void ext4_mb_show_pa(struct super_block *sb)
{
ext4_group_t i, ngroups;
if (ext4_test_mount_flag(sb, EXT4_MF_FS_ABORTED))
return;
ngroups = ext4_get_groups_count(sb);
mb_debug(sb, "groups: ");
for (i = 0; i < ngroups; i++) {
struct ext4_group_info *grp = ext4_get_group_info(sb, i);
struct ext4_prealloc_space *pa;
ext4_grpblk_t start;
struct list_head *cur;
ext4_lock_group(sb, i);
list_for_each(cur, &grp->bb_prealloc_list) {
pa = list_entry(cur, struct ext4_prealloc_space,
pa_group_list);
spin_lock(&pa->pa_lock);
ext4_get_group_no_and_offset(sb, pa->pa_pstart,
NULL, &start);
spin_unlock(&pa->pa_lock);
mb_debug(sb, "PA:%u:%d:%d\n", i, start,
pa->pa_len);
}
ext4_unlock_group(sb, i);
mb_debug(sb, "%u: %d/%d\n", i, grp->bb_free,
grp->bb_fragments);
}
}
static void ext4_mb_show_ac(struct ext4_allocation_context *ac)
{
struct super_block *sb = ac->ac_sb;
if (ext4_test_mount_flag(sb, EXT4_MF_FS_ABORTED))
return;
mb_debug(sb, "Can't allocate:"
" Allocation context details:");
mb_debug(sb, "status %u flags 0x%x",
ac->ac_status, ac->ac_flags);
mb_debug(sb, "orig %lu/%lu/%lu@%lu, "
"goal %lu/%lu/%lu@%lu, "
"best %lu/%lu/%lu@%lu cr %d",
(unsigned long)ac->ac_o_ex.fe_group,
(unsigned long)ac->ac_o_ex.fe_start,
(unsigned long)ac->ac_o_ex.fe_len,
(unsigned long)ac->ac_o_ex.fe_logical,
(unsigned long)ac->ac_g_ex.fe_group,
(unsigned long)ac->ac_g_ex.fe_start,
(unsigned long)ac->ac_g_ex.fe_len,
(unsigned long)ac->ac_g_ex.fe_logical,
(unsigned long)ac->ac_b_ex.fe_group,
(unsigned long)ac->ac_b_ex.fe_start,
(unsigned long)ac->ac_b_ex.fe_len,
(unsigned long)ac->ac_b_ex.fe_logical,
(int)ac->ac_criteria);
mb_debug(sb, "%u found", ac->ac_found);
ext4_mb_show_pa(sb);
}
#else
static inline void ext4_mb_show_pa(struct super_block *sb)
{
return;
}
static inline void ext4_mb_show_ac(struct ext4_allocation_context *ac)
{
ext4_mb_show_pa(ac->ac_sb);
return;
}
#endif
/*
* We use locality group preallocation for small size file. The size of the
* file is determined by the current size or the resulting size after
* allocation which ever is larger
*
* One can tune this size via /sys/fs/ext4/<partition>/mb_stream_req
*/
static void ext4_mb_group_or_file(struct ext4_allocation_context *ac)
{
struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
int bsbits = ac->ac_sb->s_blocksize_bits;
loff_t size, isize;
if (!(ac->ac_flags & EXT4_MB_HINT_DATA))
return;
if (unlikely(ac->ac_flags & EXT4_MB_HINT_GOAL_ONLY))
return;
size = ac->ac_o_ex.fe_logical + EXT4_C2B(sbi, ac->ac_o_ex.fe_len);
isize = (i_size_read(ac->ac_inode) + ac->ac_sb->s_blocksize - 1)
>> bsbits;
if ((size == isize) && !ext4_fs_is_busy(sbi) &&
!inode_is_open_for_write(ac->ac_inode)) {
ac->ac_flags |= EXT4_MB_HINT_NOPREALLOC;
return;
}
if (sbi->s_mb_group_prealloc <= 0) {
ac->ac_flags |= EXT4_MB_STREAM_ALLOC;
return;
}
/* don't use group allocation for large files */
size = max(size, isize);
if (size > sbi->s_mb_stream_request) {
ac->ac_flags |= EXT4_MB_STREAM_ALLOC;
return;
}
BUG_ON(ac->ac_lg != NULL);
/*
* locality group prealloc space are per cpu. The reason for having
* per cpu locality group is to reduce the contention between block
* request from multiple CPUs.
*/
ac->ac_lg = raw_cpu_ptr(sbi->s_locality_groups);
/* we're going to use group allocation */
ac->ac_flags |= EXT4_MB_HINT_GROUP_ALLOC;
/* serialize all allocations in the group */
mutex_lock(&ac->ac_lg->lg_mutex);
}
static noinline_for_stack int
ext4_mb_initialize_context(struct ext4_allocation_context *ac,
struct ext4_allocation_request *ar)
{
struct super_block *sb = ar->inode->i_sb;
struct ext4_sb_info *sbi = EXT4_SB(sb);
struct ext4_super_block *es = sbi->s_es;
ext4_group_t group;
unsigned int len;
ext4_fsblk_t goal;
ext4_grpblk_t block;
/* we can't allocate > group size */
len = ar->len;
/* just a dirty hack to filter too big requests */
if (len >= EXT4_CLUSTERS_PER_GROUP(sb))
len = EXT4_CLUSTERS_PER_GROUP(sb);
/* start searching from the goal */
goal = ar->goal;
if (goal < le32_to_cpu(es->s_first_data_block) ||
goal >= ext4_blocks_count(es))
goal = le32_to_cpu(es->s_first_data_block);
ext4_get_group_no_and_offset(sb, goal, &group, &block);
/* set up allocation goals */
ac->ac_b_ex.fe_logical = EXT4_LBLK_CMASK(sbi, ar->logical);
ac->ac_status = AC_STATUS_CONTINUE;
ac->ac_sb = sb;
ac->ac_inode = ar->inode;
ac->ac_o_ex.fe_logical = ac->ac_b_ex.fe_logical;
ac->ac_o_ex.fe_group = group;
ac->ac_o_ex.fe_start = block;
ac->ac_o_ex.fe_len = len;
ac->ac_g_ex = ac->ac_o_ex;
ac->ac_flags = ar->flags;
/* we have to define context: we'll work with a file or
* locality group. this is a policy, actually */
ext4_mb_group_or_file(ac);
mb_debug(sb, "init ac: %u blocks @ %u, goal %u, flags 0x%x, 2^%d, "
"left: %u/%u, right %u/%u to %swritable\n",
(unsigned) ar->len, (unsigned) ar->logical,
(unsigned) ar->goal, ac->ac_flags, ac->ac_2order,
(unsigned) ar->lleft, (unsigned) ar->pleft,
(unsigned) ar->lright, (unsigned) ar->pright,
inode_is_open_for_write(ar->inode) ? "" : "non-");
return 0;
}
static noinline_for_stack void
ext4_mb_discard_lg_preallocations(struct super_block *sb,
struct ext4_locality_group *lg,
int order, int total_entries)
{
ext4_group_t group = 0;
struct ext4_buddy e4b;
struct list_head discard_list;
struct ext4_prealloc_space *pa, *tmp;
mb_debug(sb, "discard locality group preallocation\n");
INIT_LIST_HEAD(&discard_list);
spin_lock(&lg->lg_prealloc_lock);
list_for_each_entry_rcu(pa, &lg->lg_prealloc_list[order],
pa_inode_list,
lockdep_is_held(&lg->lg_prealloc_lock)) {
spin_lock(&pa->pa_lock);
if (atomic_read(&pa->pa_count)) {
/*
* This is the pa that we just used
* for block allocation. So don't
* free that
*/
spin_unlock(&pa->pa_lock);
continue;
}
if (pa->pa_deleted) {
spin_unlock(&pa->pa_lock);
continue;
}
/* only lg prealloc space */
BUG_ON(pa->pa_type != MB_GROUP_PA);
/* seems this one can be freed ... */
ext4_mb_mark_pa_deleted(sb, pa);
spin_unlock(&pa->pa_lock);
list_del_rcu(&pa->pa_inode_list);
list_add(&pa->u.pa_tmp_list, &discard_list);
total_entries--;
if (total_entries <= 5) {
/*
* we want to keep only 5 entries
* allowing it to grow to 8. This
* mak sure we don't call discard
* soon for this list.
*/
break;
}
}
spin_unlock(&lg->lg_prealloc_lock);
list_for_each_entry_safe(pa, tmp, &discard_list, u.pa_tmp_list) {
int err;
group = ext4_get_group_number(sb, pa->pa_pstart);
err = ext4_mb_load_buddy_gfp(sb, group, &e4b,
GFP_NOFS|__GFP_NOFAIL);
if (err) {
ext4_error_err(sb, -err, "Error %d loading buddy information for %u",
err, group);
continue;
}
ext4_lock_group(sb, group);
list_del(&pa->pa_group_list);
ext4_mb_release_group_pa(&e4b, pa);
ext4_unlock_group(sb, group);
ext4_mb_unload_buddy(&e4b);
list_del(&pa->u.pa_tmp_list);
call_rcu(&(pa)->u.pa_rcu, ext4_mb_pa_callback);
}
}
/*
* We have incremented pa_count. So it cannot be freed at this
* point. Also we hold lg_mutex. So no parallel allocation is
* possible from this lg. That means pa_free cannot be updated.
*
* A parallel ext4_mb_discard_group_preallocations is possible.
* which can cause the lg_prealloc_list to be updated.
*/
static void ext4_mb_add_n_trim(struct ext4_allocation_context *ac)
{
int order, added = 0, lg_prealloc_count = 1;
struct super_block *sb = ac->ac_sb;
struct ext4_locality_group *lg = ac->ac_lg;
struct ext4_prealloc_space *tmp_pa, *pa = ac->ac_pa;
order = fls(pa->pa_free) - 1;
if (order > PREALLOC_TB_SIZE - 1)
/* The max size of hash table is PREALLOC_TB_SIZE */
order = PREALLOC_TB_SIZE - 1;
/* Add the prealloc space to lg */
spin_lock(&lg->lg_prealloc_lock);
list_for_each_entry_rcu(tmp_pa, &lg->lg_prealloc_list[order],
pa_inode_list,
lockdep_is_held(&lg->lg_prealloc_lock)) {
spin_lock(&tmp_pa->pa_lock);
if (tmp_pa->pa_deleted) {
spin_unlock(&tmp_pa->pa_lock);
continue;
}
if (!added && pa->pa_free < tmp_pa->pa_free) {
/* Add to the tail of the previous entry */
list_add_tail_rcu(&pa->pa_inode_list,
&tmp_pa->pa_inode_list);
added = 1;
/*
* we want to count the total
* number of entries in the list
*/
}
spin_unlock(&tmp_pa->pa_lock);
lg_prealloc_count++;
}
if (!added)
list_add_tail_rcu(&pa->pa_inode_list,
&lg->lg_prealloc_list[order]);
spin_unlock(&lg->lg_prealloc_lock);
/* Now trim the list to be not more than 8 elements */
if (lg_prealloc_count > 8) {
ext4_mb_discard_lg_preallocations(sb, lg,
order, lg_prealloc_count);
return;
}
return ;
}
/*
* if per-inode prealloc list is too long, trim some PA
*/
static void ext4_mb_trim_inode_pa(struct inode *inode)
{
struct ext4_inode_info *ei = EXT4_I(inode);
struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
int count, delta;
count = atomic_read(&ei->i_prealloc_active);
delta = (sbi->s_mb_max_inode_prealloc >> 2) + 1;
if (count > sbi->s_mb_max_inode_prealloc + delta) {
count -= sbi->s_mb_max_inode_prealloc;
ext4_discard_preallocations(inode, count);
}
}
/*
* release all resource we used in allocation
*/
static int ext4_mb_release_context(struct ext4_allocation_context *ac)
{
struct inode *inode = ac->ac_inode;
struct ext4_inode_info *ei = EXT4_I(inode);
struct ext4_sb_info *sbi = EXT4_SB(ac->ac_sb);
struct ext4_prealloc_space *pa = ac->ac_pa;
if (pa) {
if (pa->pa_type == MB_GROUP_PA) {
/* see comment in ext4_mb_use_group_pa() */
spin_lock(&pa->pa_lock);
pa->pa_pstart += EXT4_C2B(sbi, ac->ac_b_ex.fe_len);
pa->pa_lstart += EXT4_C2B(sbi, ac->ac_b_ex.fe_len);
pa->pa_free -= ac->ac_b_ex.fe_len;
pa->pa_len -= ac->ac_b_ex.fe_len;
spin_unlock(&pa->pa_lock);
/*
* We want to add the pa to the right bucket.
* Remove it from the list and while adding
* make sure the list to which we are adding
* doesn't grow big.
*/
if (likely(pa->pa_free)) {
spin_lock(pa->pa_obj_lock);
list_del_rcu(&pa->pa_inode_list);
spin_unlock(pa->pa_obj_lock);
ext4_mb_add_n_trim(ac);
}
}
if (pa->pa_type == MB_INODE_PA) {
/*
* treat per-inode prealloc list as a lru list, then try
* to trim the least recently used PA.
*/
spin_lock(pa->pa_obj_lock);
list_move(&pa->pa_inode_list, &ei->i_prealloc_list);
spin_unlock(pa->pa_obj_lock);
}
ext4_mb_put_pa(ac, ac->ac_sb, pa);
}
if (ac->ac_bitmap_page)
put_page(ac->ac_bitmap_page);
if (ac->ac_buddy_page)
put_page(ac->ac_buddy_page);
if (ac->ac_flags & EXT4_MB_HINT_GROUP_ALLOC)
mutex_unlock(&ac->ac_lg->lg_mutex);
ext4_mb_collect_stats(ac);
ext4_mb_trim_inode_pa(inode);
return 0;
}
static int ext4_mb_discard_preallocations(struct super_block *sb, int needed)
{
ext4_group_t i, ngroups = ext4_get_groups_count(sb);
int ret;
int freed = 0;
trace_ext4_mb_discard_preallocations(sb, needed);
for (i = 0; i < ngroups && needed > 0; i++) {
ret = ext4_mb_discard_group_preallocations(sb, i, needed);
freed += ret;
needed -= ret;
}
return freed;
}
static bool ext4_mb_discard_preallocations_should_retry(struct super_block *sb,
struct ext4_allocation_context *ac, u64 *seq)
{
int freed;
u64 seq_retry = 0;
bool ret = false;
freed = ext4_mb_discard_preallocations(sb, ac->ac_o_ex.fe_len);
if (freed) {
ret = true;
goto out_dbg;
}
seq_retry = ext4_get_discard_pa_seq_sum();
if (!(ac->ac_flags & EXT4_MB_STRICT_CHECK) || seq_retry != *seq) {
ac->ac_flags |= EXT4_MB_STRICT_CHECK;
*seq = seq_retry;
ret = true;
}
out_dbg:
mb_debug(sb, "freed %d, retry ? %s\n", freed, ret ? "yes" : "no");
return ret;
}
static ext4_fsblk_t ext4_mb_new_blocks_simple(handle_t *handle,
struct ext4_allocation_request *ar, int *errp);
/*
* Main entry point into mballoc to allocate blocks
* it tries to use preallocation first, then falls back
* to usual allocation
*/
ext4_fsblk_t ext4_mb_new_blocks(handle_t *handle,
struct ext4_allocation_request *ar, int *errp)
{
struct ext4_allocation_context *ac = NULL;
struct ext4_sb_info *sbi;
struct super_block *sb;
ext4_fsblk_t block = 0;
unsigned int inquota = 0;
unsigned int reserv_clstrs = 0;
u64 seq;
might_sleep();
sb = ar->inode->i_sb;
sbi = EXT4_SB(sb);
trace_ext4_request_blocks(ar);
if (sbi->s_mount_state & EXT4_FC_REPLAY)
return ext4_mb_new_blocks_simple(handle, ar, errp);
/* Allow to use superuser reservation for quota file */
if (ext4_is_quota_file(ar->inode))
ar->flags |= EXT4_MB_USE_ROOT_BLOCKS;
if ((ar->flags & EXT4_MB_DELALLOC_RESERVED) == 0) {
/* Without delayed allocation we need to verify
* there is enough free blocks to do block allocation
* and verify allocation doesn't exceed the quota limits.
*/
while (ar->len &&
ext4_claim_free_clusters(sbi, ar->len, ar->flags)) {
/* let others to free the space */
cond_resched();
ar->len = ar->len >> 1;
}
if (!ar->len) {
ext4_mb_show_pa(sb);
*errp = -ENOSPC;
return 0;
}
reserv_clstrs = ar->len;
if (ar->flags & EXT4_MB_USE_ROOT_BLOCKS) {
dquot_alloc_block_nofail(ar->inode,
EXT4_C2B(sbi, ar->len));
} else {
while (ar->len &&
dquot_alloc_block(ar->inode,
EXT4_C2B(sbi, ar->len))) {
ar->flags |= EXT4_MB_HINT_NOPREALLOC;
ar->len--;
}
}
inquota = ar->len;
if (ar->len == 0) {
*errp = -EDQUOT;
goto out;
}
}
ac = kmem_cache_zalloc(ext4_ac_cachep, GFP_NOFS);
if (!ac) {
ar->len = 0;
*errp = -ENOMEM;
goto out;
}
*errp = ext4_mb_initialize_context(ac, ar);
if (*errp) {
ar->len = 0;
goto out;
}
ac->ac_op = EXT4_MB_HISTORY_PREALLOC;
seq = this_cpu_read(discard_pa_seq);
if (!ext4_mb_use_preallocated(ac)) {
ac->ac_op = EXT4_MB_HISTORY_ALLOC;
ext4_mb_normalize_request(ac, ar);
*errp = ext4_mb_pa_alloc(ac);
if (*errp)
goto errout;
repeat:
/* allocate space in core */
*errp = ext4_mb_regular_allocator(ac);
/*
* pa allocated above is added to grp->bb_prealloc_list only
* when we were able to allocate some block i.e. when
* ac->ac_status == AC_STATUS_FOUND.
* And error from above mean ac->ac_status != AC_STATUS_FOUND
* So we have to free this pa here itself.
*/
if (*errp) {
ext4_mb_pa_free(ac);
ext4_discard_allocated_blocks(ac);
goto errout;
}
if (ac->ac_status == AC_STATUS_FOUND &&
ac->ac_o_ex.fe_len >= ac->ac_f_ex.fe_len)
ext4_mb_pa_free(ac);
}
if (likely(ac->ac_status == AC_STATUS_FOUND)) {
*errp = ext4_mb_mark_diskspace_used(ac, handle, reserv_clstrs);
if (*errp) {
ext4_discard_allocated_blocks(ac);
goto errout;
} else {
block = ext4_grp_offs_to_block(sb, &ac->ac_b_ex);
ar->len = ac->ac_b_ex.fe_len;
}
} else {
if (ext4_mb_discard_preallocations_should_retry(sb, ac, &seq))
goto repeat;
/*
* If block allocation fails then the pa allocated above
* needs to be freed here itself.
*/
ext4_mb_pa_free(ac);
*errp = -ENOSPC;
}
errout:
if (*errp) {
ac->ac_b_ex.fe_len = 0;
ar->len = 0;
ext4_mb_show_ac(ac);
}
ext4_mb_release_context(ac);
out:
if (ac)
kmem_cache_free(ext4_ac_cachep, ac);
if (inquota && ar->len < inquota)
dquot_free_block(ar->inode, EXT4_C2B(sbi, inquota - ar->len));
if (!ar->len) {
if ((ar->flags & EXT4_MB_DELALLOC_RESERVED) == 0)
/* release all the reserved blocks if non delalloc */
percpu_counter_sub(&sbi->s_dirtyclusters_counter,
reserv_clstrs);
}
trace_ext4_allocate_blocks(ar, (unsigned long long)block);
return block;
}
/*
* We can merge two free data extents only if the physical blocks
* are contiguous, AND the extents were freed by the same transaction,
* AND the blocks are associated with the same group.
*/
static void ext4_try_merge_freed_extent(struct ext4_sb_info *sbi,
struct ext4_free_data *entry,
struct ext4_free_data *new_entry,
struct rb_root *entry_rb_root)
{
if ((entry->efd_tid != new_entry->efd_tid) ||
(entry->efd_group != new_entry->efd_group))
return;
if (entry->efd_start_cluster + entry->efd_count ==
new_entry->efd_start_cluster) {
new_entry->efd_start_cluster = entry->efd_start_cluster;
new_entry->efd_count += entry->efd_count;
} else if (new_entry->efd_start_cluster + new_entry->efd_count ==
entry->efd_start_cluster) {
new_entry->efd_count += entry->efd_count;
} else
return;
spin_lock(&sbi->s_md_lock);
list_del(&entry->efd_list);
spin_unlock(&sbi->s_md_lock);
rb_erase(&entry->efd_node, entry_rb_root);
kmem_cache_free(ext4_free_data_cachep, entry);
}
static noinline_for_stack int
ext4_mb_free_metadata(handle_t *handle, struct ext4_buddy *e4b,
struct ext4_free_data *new_entry)
{
ext4_group_t group = e4b->bd_group;
ext4_grpblk_t cluster;
ext4_grpblk_t clusters = new_entry->efd_count;
struct ext4_free_data *entry;
struct ext4_group_info *db = e4b->bd_info;
struct super_block *sb = e4b->bd_sb;
struct ext4_sb_info *sbi = EXT4_SB(sb);
struct rb_node **n = &db->bb_free_root.rb_node, *node;
struct rb_node *parent = NULL, *new_node;
BUG_ON(!ext4_handle_valid(handle));
BUG_ON(e4b->bd_bitmap_page == NULL);
BUG_ON(e4b->bd_buddy_page == NULL);
new_node = &new_entry->efd_node;
cluster = new_entry->efd_start_cluster;
if (!*n) {
/* first free block exent. We need to
protect buddy cache from being freed,
* otherwise we'll refresh it from
* on-disk bitmap and lose not-yet-available
* blocks */
get_page(e4b->bd_buddy_page);
get_page(e4b->bd_bitmap_page);
}
while (*n) {
parent = *n;
entry = rb_entry(parent, struct ext4_free_data, efd_node);
if (cluster < entry->efd_start_cluster)
n = &(*n)->rb_left;
else if (cluster >= (entry->efd_start_cluster + entry->efd_count))
n = &(*n)->rb_right;
else {
ext4_grp_locked_error(sb, group, 0,
ext4_group_first_block_no(sb, group) +
EXT4_C2B(sbi, cluster),
"Block already on to-be-freed list");
kmem_cache_free(ext4_free_data_cachep, new_entry);
return 0;
}
}
rb_link_node(new_node, parent, n);
rb_insert_color(new_node, &db->bb_free_root);
/* Now try to see the extent can be merged to left and right */
node = rb_prev(new_node);
if (node) {
entry = rb_entry(node, struct ext4_free_data, efd_node);
ext4_try_merge_freed_extent(sbi, entry, new_entry,
&(db->bb_free_root));
}
node = rb_next(new_node);
if (node) {
entry = rb_entry(node, struct ext4_free_data, efd_node);
ext4_try_merge_freed_extent(sbi, entry, new_entry,
&(db->bb_free_root));
}
spin_lock(&sbi->s_md_lock);
list_add_tail(&new_entry->efd_list, &sbi->s_freed_data_list);
sbi->s_mb_free_pending += clusters;
spin_unlock(&sbi->s_md_lock);
return 0;
}
/*
* Simple allocator for Ext4 fast commit replay path. It searches for blocks
* linearly starting at the goal block and also excludes the blocks which
* are going to be in use after fast commit replay.
*/
static ext4_fsblk_t ext4_mb_new_blocks_simple(handle_t *handle,
struct ext4_allocation_request *ar, int *errp)
{
struct buffer_head *bitmap_bh;
struct super_block *sb = ar->inode->i_sb;
ext4_group_t group;
ext4_grpblk_t blkoff;
int i = sb->s_blocksize;
ext4_fsblk_t goal, block;
struct ext4_super_block *es = EXT4_SB(sb)->s_es;
goal = ar->goal;
if (goal < le32_to_cpu(es->s_first_data_block) ||
goal >= ext4_blocks_count(es))
goal = le32_to_cpu(es->s_first_data_block);
ar->len = 0;
ext4_get_group_no_and_offset(sb, goal, &group, &blkoff);
for (; group < ext4_get_groups_count(sb); group++) {
bitmap_bh = ext4_read_block_bitmap(sb, group);
if (IS_ERR(bitmap_bh)) {
*errp = PTR_ERR(bitmap_bh);
pr_warn("Failed to read block bitmap\n");
return 0;
}
ext4_get_group_no_and_offset(sb,
max(ext4_group_first_block_no(sb, group), goal),
NULL, &blkoff);
i = mb_find_next_zero_bit(bitmap_bh->b_data, sb->s_blocksize,
blkoff);
brelse(bitmap_bh);
if (i >= sb->s_blocksize)
continue;
if (ext4_fc_replay_check_excluded(sb,
ext4_group_first_block_no(sb, group) + i))
continue;
break;
}
if (group >= ext4_get_groups_count(sb) && i >= sb->s_blocksize)
return 0;
block = ext4_group_first_block_no(sb, group) + i;
ext4_mb_mark_bb(sb, block, 1, 1);
ar->len = 1;
return block;
}
static void ext4_free_blocks_simple(struct inode *inode, ext4_fsblk_t block,
unsigned long count)
{
struct buffer_head *bitmap_bh;
struct super_block *sb = inode->i_sb;
struct ext4_group_desc *gdp;
struct buffer_head *gdp_bh;
ext4_group_t group;
ext4_grpblk_t blkoff;
int already_freed = 0, err, i;
ext4_get_group_no_and_offset(sb, block, &group, &blkoff);
bitmap_bh = ext4_read_block_bitmap(sb, group);
if (IS_ERR(bitmap_bh)) {
err = PTR_ERR(bitmap_bh);
pr_warn("Failed to read block bitmap\n");
return;
}
gdp = ext4_get_group_desc(sb, group, &gdp_bh);
if (!gdp)
return;
for (i = 0; i < count; i++) {
if (!mb_test_bit(blkoff + i, bitmap_bh->b_data))
already_freed++;
}
mb_clear_bits(bitmap_bh->b_data, blkoff, count);
err = ext4_handle_dirty_metadata(NULL, NULL, bitmap_bh);
if (err)
return;
ext4_free_group_clusters_set(
sb, gdp, ext4_free_group_clusters(sb, gdp) +
count - already_freed);
ext4_block_bitmap_csum_set(sb, group, gdp, bitmap_bh);
ext4_group_desc_csum_set(sb, group, gdp);
ext4_handle_dirty_metadata(NULL, NULL, gdp_bh);
sync_dirty_buffer(bitmap_bh);
sync_dirty_buffer(gdp_bh);
brelse(bitmap_bh);
}
/**
* ext4_free_blocks() -- Free given blocks and update quota
* @handle: handle for this transaction
* @inode: inode
* @bh: optional buffer of the block to be freed
* @block: starting physical block to be freed
* @count: number of blocks to be freed
* @flags: flags used by ext4_free_blocks
*/
void ext4_free_blocks(handle_t *handle, struct inode *inode,
struct buffer_head *bh, ext4_fsblk_t block,
unsigned long count, int flags)
{
struct buffer_head *bitmap_bh = NULL;
struct super_block *sb = inode->i_sb;
struct ext4_group_desc *gdp;
unsigned int overflow;
ext4_grpblk_t bit;
struct buffer_head *gd_bh;
ext4_group_t block_group;
struct ext4_sb_info *sbi;
struct ext4_buddy e4b;
unsigned int count_clusters;
int err = 0;
int ret;
sbi = EXT4_SB(sb);
if (sbi->s_mount_state & EXT4_FC_REPLAY) {
ext4_free_blocks_simple(inode, block, count);
return;
}
might_sleep();
if (bh) {
if (block)
BUG_ON(block != bh->b_blocknr);
else
block = bh->b_blocknr;
}
if (!(flags & EXT4_FREE_BLOCKS_VALIDATED) &&
!ext4_inode_block_valid(inode, block, count)) {
ext4_error(sb, "Freeing blocks not in datazone - "
"block = %llu, count = %lu", block, count);
goto error_return;
}
ext4_debug("freeing block %llu\n", block);
trace_ext4_free_blocks(inode, block, count, flags);
if (bh && (flags & EXT4_FREE_BLOCKS_FORGET)) {
BUG_ON(count > 1);
ext4_forget(handle, flags & EXT4_FREE_BLOCKS_METADATA,
inode, bh, block);
}
/*
* If the extent to be freed does not begin on a cluster
* boundary, we need to deal with partial clusters at the
* beginning and end of the extent. Normally we will free
* blocks at the beginning or the end unless we are explicitly
* requested to avoid doing so.
*/
overflow = EXT4_PBLK_COFF(sbi, block);
if (overflow) {
if (flags & EXT4_FREE_BLOCKS_NOFREE_FIRST_CLUSTER) {
overflow = sbi->s_cluster_ratio - overflow;
block += overflow;
if (count > overflow)
count -= overflow;
else
return;
} else {
block -= overflow;
count += overflow;
}
}
overflow = EXT4_LBLK_COFF(sbi, count);
if (overflow) {
if (flags & EXT4_FREE_BLOCKS_NOFREE_LAST_CLUSTER) {
if (count > overflow)
count -= overflow;
else
return;
} else
count += sbi->s_cluster_ratio - overflow;
}
if (!bh && (flags & EXT4_FREE_BLOCKS_FORGET)) {
int i;
int is_metadata = flags & EXT4_FREE_BLOCKS_METADATA;
for (i = 0; i < count; i++) {
cond_resched();
if (is_metadata)
bh = sb_find_get_block(inode->i_sb, block + i);
ext4_forget(handle, is_metadata, inode, bh, block + i);
}
}
do_more:
overflow = 0;
ext4_get_group_no_and_offset(sb, block, &block_group, &bit);
if (unlikely(EXT4_MB_GRP_BBITMAP_CORRUPT(
ext4_get_group_info(sb, block_group))))
return;
/*
* Check to see if we are freeing blocks across a group
* boundary.
*/
if (EXT4_C2B(sbi, bit) + count > EXT4_BLOCKS_PER_GROUP(sb)) {
overflow = EXT4_C2B(sbi, bit) + count -
EXT4_BLOCKS_PER_GROUP(sb);
count -= overflow;
}
count_clusters = EXT4_NUM_B2C(sbi, count);
bitmap_bh = ext4_read_block_bitmap(sb, block_group);
if (IS_ERR(bitmap_bh)) {
err = PTR_ERR(bitmap_bh);
bitmap_bh = NULL;
goto error_return;
}
gdp = ext4_get_group_desc(sb, block_group, &gd_bh);
if (!gdp) {
err = -EIO;
goto error_return;
}
if (in_range(ext4_block_bitmap(sb, gdp), block, count) ||
in_range(ext4_inode_bitmap(sb, gdp), block, count) ||
in_range(block, ext4_inode_table(sb, gdp),
sbi->s_itb_per_group) ||
in_range(block + count - 1, ext4_inode_table(sb, gdp),
sbi->s_itb_per_group)) {
ext4_error(sb, "Freeing blocks in system zone - "
"Block = %llu, count = %lu", block, count);
/* err = 0. ext4_std_error should be a no op */
goto error_return;
}
BUFFER_TRACE(bitmap_bh, "getting write access");
err = ext4_journal_get_write_access(handle, sb, bitmap_bh,
EXT4_JTR_NONE);
if (err)
goto error_return;
/*
* We are about to modify some metadata. Call the journal APIs
* to unshare ->b_data if a currently-committing transaction is
* using it
*/
BUFFER_TRACE(gd_bh, "get_write_access");
err = ext4_journal_get_write_access(handle, sb, gd_bh, EXT4_JTR_NONE);
if (err)
goto error_return;
#ifdef AGGRESSIVE_CHECK
{
int i;
for (i = 0; i < count_clusters; i++)
BUG_ON(!mb_test_bit(bit + i, bitmap_bh->b_data));
}
#endif
trace_ext4_mballoc_free(sb, inode, block_group, bit, count_clusters);
/* __GFP_NOFAIL: retry infinitely, ignore TIF_MEMDIE and memcg limit. */
err = ext4_mb_load_buddy_gfp(sb, block_group, &e4b,
GFP_NOFS|__GFP_NOFAIL);
if (err)
goto error_return;
/*
* We need to make sure we don't reuse the freed block until after the
* transaction is committed. We make an exception if the inode is to be
* written in writeback mode since writeback mode has weak data
* consistency guarantees.
*/
if (ext4_handle_valid(handle) &&
((flags & EXT4_FREE_BLOCKS_METADATA) ||
!ext4_should_writeback_data(inode))) {
struct ext4_free_data *new_entry;
/*
* We use __GFP_NOFAIL because ext4_free_blocks() is not allowed
* to fail.
*/
new_entry = kmem_cache_alloc(ext4_free_data_cachep,
GFP_NOFS|__GFP_NOFAIL);
new_entry->efd_start_cluster = bit;
new_entry->efd_group = block_group;
new_entry->efd_count = count_clusters;
new_entry->efd_tid = handle->h_transaction->t_tid;
ext4_lock_group(sb, block_group);
mb_clear_bits(bitmap_bh->b_data, bit, count_clusters);
ext4_mb_free_metadata(handle, &e4b, new_entry);
} else {
/* need to update group_info->bb_free and bitmap
* with group lock held. generate_buddy look at
* them with group lock_held
*/
if (test_opt(sb, DISCARD)) {
err = ext4_issue_discard(sb, block_group, bit, count,
NULL);
if (err && err != -EOPNOTSUPP)
ext4_msg(sb, KERN_WARNING, "discard request in"
" group:%d block:%d count:%lu failed"
" with %d", block_group, bit, count,
err);
} else
EXT4_MB_GRP_CLEAR_TRIMMED(e4b.bd_info);
ext4_lock_group(sb, block_group);
mb_clear_bits(bitmap_bh->b_data, bit, count_clusters);
mb_free_blocks(inode, &e4b, bit, count_clusters);
}
ret = ext4_free_group_clusters(sb, gdp) + count_clusters;
ext4_free_group_clusters_set(sb, gdp, ret);
ext4_block_bitmap_csum_set(sb, block_group, gdp, bitmap_bh);
ext4_group_desc_csum_set(sb, block_group, gdp);
ext4_unlock_group(sb, block_group);
if (sbi->s_log_groups_per_flex) {
ext4_group_t flex_group = ext4_flex_group(sbi, block_group);
atomic64_add(count_clusters,
&sbi_array_rcu_deref(sbi, s_flex_groups,
flex_group)->free_clusters);
}
/*
* on a bigalloc file system, defer the s_freeclusters_counter
* update to the caller (ext4_remove_space and friends) so they
* can determine if a cluster freed here should be rereserved
*/
if (!(flags & EXT4_FREE_BLOCKS_RERESERVE_CLUSTER)) {
if (!(flags & EXT4_FREE_BLOCKS_NO_QUOT_UPDATE))
dquot_free_block(inode, EXT4_C2B(sbi, count_clusters));
percpu_counter_add(&sbi->s_freeclusters_counter,
count_clusters);
}
ext4_mb_unload_buddy(&e4b);
/* We dirtied the bitmap block */
BUFFER_TRACE(bitmap_bh, "dirtied bitmap block");
err = ext4_handle_dirty_metadata(handle, NULL, bitmap_bh);
/* And the group descriptor block */
BUFFER_TRACE(gd_bh, "dirtied group descriptor block");
ret = ext4_handle_dirty_metadata(handle, NULL, gd_bh);
if (!err)
err = ret;
if (overflow && !err) {
block += count;
count = overflow;
put_bh(bitmap_bh);
goto do_more;
}
error_return:
brelse(bitmap_bh);
ext4_std_error(sb, err);
return;
}
/**
* ext4_group_add_blocks() -- Add given blocks to an existing group
* @handle: handle to this transaction
* @sb: super block
* @block: start physical block to add to the block group
* @count: number of blocks to free
*
* This marks the blocks as free in the bitmap and buddy.
*/
int ext4_group_add_blocks(handle_t *handle, struct super_block *sb,
ext4_fsblk_t block, unsigned long count)
{
struct buffer_head *bitmap_bh = NULL;
struct buffer_head *gd_bh;
ext4_group_t block_group;
ext4_grpblk_t bit;
unsigned int i;
struct ext4_group_desc *desc;
struct ext4_sb_info *sbi = EXT4_SB(sb);
struct ext4_buddy e4b;
int err = 0, ret, free_clusters_count;
ext4_grpblk_t clusters_freed;
ext4_fsblk_t first_cluster = EXT4_B2C(sbi, block);
ext4_fsblk_t last_cluster = EXT4_B2C(sbi, block + count - 1);
unsigned long cluster_count = last_cluster - first_cluster + 1;
ext4_debug("Adding block(s) %llu-%llu\n", block, block + count - 1);
if (count == 0)
return 0;
ext4_get_group_no_and_offset(sb, block, &block_group, &bit);
/*
* Check to see if we are freeing blocks across a group
* boundary.
*/
if (bit + cluster_count > EXT4_CLUSTERS_PER_GROUP(sb)) {
ext4_warning(sb, "too many blocks added to group %u",
block_group);
err = -EINVAL;
goto error_return;
}
bitmap_bh = ext4_read_block_bitmap(sb, block_group);
if (IS_ERR(bitmap_bh)) {
err = PTR_ERR(bitmap_bh);
bitmap_bh = NULL;
goto error_return;
}
desc = ext4_get_group_desc(sb, block_group, &gd_bh);
if (!desc) {
err = -EIO;
goto error_return;
}
if (in_range(ext4_block_bitmap(sb, desc), block, count) ||
in_range(ext4_inode_bitmap(sb, desc), block, count) ||
in_range(block, ext4_inode_table(sb, desc), sbi->s_itb_per_group) ||
in_range(block + count - 1, ext4_inode_table(sb, desc),
sbi->s_itb_per_group)) {
ext4_error(sb, "Adding blocks in system zones - "
"Block = %llu, count = %lu",
block, count);
err = -EINVAL;
goto error_return;
}
BUFFER_TRACE(bitmap_bh, "getting write access");
err = ext4_journal_get_write_access(handle, sb, bitmap_bh,
EXT4_JTR_NONE);
if (err)
goto error_return;
/*
* We are about to modify some metadata. Call the journal APIs
* to unshare ->b_data if a currently-committing transaction is
* using it
*/
BUFFER_TRACE(gd_bh, "get_write_access");
err = ext4_journal_get_write_access(handle, sb, gd_bh, EXT4_JTR_NONE);
if (err)
goto error_return;
for (i = 0, clusters_freed = 0; i < cluster_count; i++) {
BUFFER_TRACE(bitmap_bh, "clear bit");
if (!mb_test_bit(bit + i, bitmap_bh->b_data)) {
ext4_error(sb, "bit already cleared for block %llu",
(ext4_fsblk_t)(block + i));
BUFFER_TRACE(bitmap_bh, "bit already cleared");
} else {
clusters_freed++;
}
}
err = ext4_mb_load_buddy(sb, block_group, &e4b);
if (err)
goto error_return;
/*
* need to update group_info->bb_free and bitmap
* with group lock held. generate_buddy look at
* them with group lock_held
*/
ext4_lock_group(sb, block_group);
mb_clear_bits(bitmap_bh->b_data, bit, cluster_count);
mb_free_blocks(NULL, &e4b, bit, cluster_count);
free_clusters_count = clusters_freed +
ext4_free_group_clusters(sb, desc);
ext4_free_group_clusters_set(sb, desc, free_clusters_count);
ext4_block_bitmap_csum_set(sb, block_group, desc, bitmap_bh);
ext4_group_desc_csum_set(sb, block_group, desc);
ext4_unlock_group(sb, block_group);
percpu_counter_add(&sbi->s_freeclusters_counter,
clusters_freed);
if (sbi->s_log_groups_per_flex) {
ext4_group_t flex_group = ext4_flex_group(sbi, block_group);
atomic64_add(clusters_freed,
&sbi_array_rcu_deref(sbi, s_flex_groups,
flex_group)->free_clusters);
}
ext4_mb_unload_buddy(&e4b);
/* We dirtied the bitmap block */
BUFFER_TRACE(bitmap_bh, "dirtied bitmap block");
err = ext4_handle_dirty_metadata(handle, NULL, bitmap_bh);
/* And the group descriptor block */
BUFFER_TRACE(gd_bh, "dirtied group descriptor block");
ret = ext4_handle_dirty_metadata(handle, NULL, gd_bh);
if (!err)
err = ret;
error_return:
brelse(bitmap_bh);
ext4_std_error(sb, err);
return err;
}
/**
* ext4_trim_extent -- function to TRIM one single free extent in the group
* @sb: super block for the file system
* @start: starting block of the free extent in the alloc. group
* @count: number of blocks to TRIM
* @e4b: ext4 buddy for the group
*
* Trim "count" blocks starting at "start" in the "group". To assure that no
* one will allocate those blocks, mark it as used in buddy bitmap. This must
* be called with under the group lock.
*/
static int ext4_trim_extent(struct super_block *sb,
int start, int count, struct ext4_buddy *e4b)
__releases(bitlock)
__acquires(bitlock)
{
struct ext4_free_extent ex;
ext4_group_t group = e4b->bd_group;
int ret = 0;
trace_ext4_trim_extent(sb, group, start, count);
assert_spin_locked(ext4_group_lock_ptr(sb, group));
ex.fe_start = start;
ex.fe_group = group;
ex.fe_len = count;
/*
* Mark blocks used, so no one can reuse them while
* being trimmed.
*/
mb_mark_used(e4b, &ex);
ext4_unlock_group(sb, group);
ret = ext4_issue_discard(sb, group, start, count, NULL);
ext4_lock_group(sb, group);
mb_free_blocks(NULL, e4b, start, ex.fe_len);
return ret;
}
static int ext4_try_to_trim_range(struct super_block *sb,
struct ext4_buddy *e4b, ext4_grpblk_t start,
ext4_grpblk_t max, ext4_grpblk_t minblocks)
__acquires(ext4_group_lock_ptr(sb, e4b->bd_group))
__releases(ext4_group_lock_ptr(sb, e4b->bd_group))
{
ext4_grpblk_t next, count, free_count;
void *bitmap;
bitmap = e4b->bd_bitmap;
start = (e4b->bd_info->bb_first_free > start) ?
e4b->bd_info->bb_first_free : start;
count = 0;
free_count = 0;
while (start <= max) {
start = mb_find_next_zero_bit(bitmap, max + 1, start);
if (start > max)
break;
next = mb_find_next_bit(bitmap, max + 1, start);
if ((next - start) >= minblocks) {
int ret = ext4_trim_extent(sb, start, next - start, e4b);
if (ret && ret != -EOPNOTSUPP)
break;
count += next - start;
}
free_count += next - start;
start = next + 1;
if (fatal_signal_pending(current)) {
count = -ERESTARTSYS;
break;
}
if (need_resched()) {
ext4_unlock_group(sb, e4b->bd_group);
cond_resched();
ext4_lock_group(sb, e4b->bd_group);
}
if ((e4b->bd_info->bb_free - free_count) < minblocks)
break;
}
return count;
}
/**
* ext4_trim_all_free -- function to trim all free space in alloc. group
* @sb: super block for file system
* @group: group to be trimmed
* @start: first group block to examine
* @max: last group block to examine
* @minblocks: minimum extent block count
*
* ext4_trim_all_free walks through group's block bitmap searching for free
* extents. When the free extent is found, mark it as used in group buddy
* bitmap. Then issue a TRIM command on this extent and free the extent in
* the group buddy bitmap.
*/
static ext4_grpblk_t
ext4_trim_all_free(struct super_block *sb, ext4_group_t group,
ext4_grpblk_t start, ext4_grpblk_t max,
ext4_grpblk_t minblocks)
{
struct ext4_buddy e4b;
int ret;
trace_ext4_trim_all_free(sb, group, start, max);
ret = ext4_mb_load_buddy(sb, group, &e4b);
if (ret) {
ext4_warning(sb, "Error %d loading buddy information for %u",
ret, group);
return ret;
}
ext4_lock_group(sb, group);
if (!EXT4_MB_GRP_WAS_TRIMMED(e4b.bd_info) ||
minblocks < atomic_read(&EXT4_SB(sb)->s_last_trim_minblks)) {
ret = ext4_try_to_trim_range(sb, &e4b, start, max, minblocks);
if (ret >= 0)
EXT4_MB_GRP_SET_TRIMMED(e4b.bd_info);
} else {
ret = 0;
}
ext4_unlock_group(sb, group);
ext4_mb_unload_buddy(&e4b);
ext4_debug("trimmed %d blocks in the group %d\n",
ret, group);
return ret;
}
/**
* ext4_trim_fs() -- trim ioctl handle function
* @sb: superblock for filesystem
* @range: fstrim_range structure
*
* start: First Byte to trim
* len: number of Bytes to trim from start
* minlen: minimum extent length in Bytes
* ext4_trim_fs goes through all allocation groups containing Bytes from
* start to start+len. For each such a group ext4_trim_all_free function
* is invoked to trim all free space.
*/
int ext4_trim_fs(struct super_block *sb, struct fstrim_range *range)
{
struct ext4_group_info *grp;
ext4_group_t group, first_group, last_group;
ext4_grpblk_t cnt = 0, first_cluster, last_cluster;
uint64_t start, end, minlen, trimmed = 0;
ext4_fsblk_t first_data_blk =
le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block);
ext4_fsblk_t max_blks = ext4_blocks_count(EXT4_SB(sb)->s_es);
int ret = 0;
start = range->start >> sb->s_blocksize_bits;
end = start + (range->len >> sb->s_blocksize_bits) - 1;
minlen = EXT4_NUM_B2C(EXT4_SB(sb),
range->minlen >> sb->s_blocksize_bits);
if (minlen > EXT4_CLUSTERS_PER_GROUP(sb) ||
start >= max_blks ||
range->len < sb->s_blocksize)
return -EINVAL;
if (end >= max_blks)
end = max_blks - 1;
if (end <= first_data_blk)
goto out;
if (start < first_data_blk)
start = first_data_blk;
/* Determine first and last group to examine based on start and end */
ext4_get_group_no_and_offset(sb, (ext4_fsblk_t) start,
&first_group, &first_cluster);
ext4_get_group_no_and_offset(sb, (ext4_fsblk_t) end,
&last_group, &last_cluster);
/* end now represents the last cluster to discard in this group */
end = EXT4_CLUSTERS_PER_GROUP(sb) - 1;
for (group = first_group; group <= last_group; group++) {
grp = ext4_get_group_info(sb, group);
/* We only do this if the grp has never been initialized */
if (unlikely(EXT4_MB_GRP_NEED_INIT(grp))) {
ret = ext4_mb_init_group(sb, group, GFP_NOFS);
if (ret)
break;
}
/*
* For all the groups except the last one, last cluster will
* always be EXT4_CLUSTERS_PER_GROUP(sb)-1, so we only need to
* change it for the last group, note that last_cluster is
* already computed earlier by ext4_get_group_no_and_offset()
*/
if (group == last_group)
end = last_cluster;
if (grp->bb_free >= minlen) {
cnt = ext4_trim_all_free(sb, group, first_cluster,
end, minlen);
if (cnt < 0) {
ret = cnt;
break;
}
trimmed += cnt;
}
/*
* For every group except the first one, we are sure
* that the first cluster to discard will be cluster #0.
*/
first_cluster = 0;
}
if (!ret)
atomic_set(&EXT4_SB(sb)->s_last_trim_minblks, minlen);
out:
range->len = EXT4_C2B(EXT4_SB(sb), trimmed) << sb->s_blocksize_bits;
return ret;
}
/* Iterate all the free extents in the group. */
int
ext4_mballoc_query_range(
struct super_block *sb,
ext4_group_t group,
ext4_grpblk_t start,
ext4_grpblk_t end,
ext4_mballoc_query_range_fn formatter,
void *priv)
{
void *bitmap;
ext4_grpblk_t next;
struct ext4_buddy e4b;
int error;
error = ext4_mb_load_buddy(sb, group, &e4b);
if (error)
return error;
bitmap = e4b.bd_bitmap;
ext4_lock_group(sb, group);
start = (e4b.bd_info->bb_first_free > start) ?
e4b.bd_info->bb_first_free : start;
if (end >= EXT4_CLUSTERS_PER_GROUP(sb))
end = EXT4_CLUSTERS_PER_GROUP(sb) - 1;
while (start <= end) {
start = mb_find_next_zero_bit(bitmap, end + 1, start);
if (start > end)
break;
next = mb_find_next_bit(bitmap, end + 1, start);
ext4_unlock_group(sb, group);
error = formatter(sb, group, start, next - start, priv);
if (error)
goto out_unload;
ext4_lock_group(sb, group);
start = next + 1;
}
ext4_unlock_group(sb, group);
out_unload:
ext4_mb_unload_buddy(&e4b);
return error;
}
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