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ext4: support GETFSMAP ioctls

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Support the GETFSMAP ioctls so that we can use the xfs free space
management tools to probe ext4 as well.  Note that this is a partial
implementation -- we only report fixed-location metadata and free space;
everything else is reported as "unknown".

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
This commit is contained in:
Darrick J. Wong 2017-04-30 00:36:53 -04:00 committed by Theodore Ts'o
parent d0649f0416
commit 0c9ec4beec
8 changed files with 1027 additions and 5 deletions
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10
fs/ext4/Makefile
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@ -4,11 +4,11 @@
obj-$(CONFIG_EXT4_FS) += ext4.o
ext4-y := balloc.o bitmap.o dir.o file.o fsync.o ialloc.o inode.o page-io.o \
ioctl.o namei.o super.o symlink.o hash.o resize.o extents.o \
ext4_jbd2.o migrate.o mballoc.o block_validity.o move_extent.o \
mmp.o indirect.o extents_status.o xattr.o xattr_user.o \
xattr_trusted.o inline.o readpage.o sysfs.o
ext4-y := balloc.o bitmap.o block_validity.o dir.o ext4_jbd2.o extents.o \
extents_status.o file.o fsmap.o fsync.o hash.o ialloc.o \
indirect.o inline.o inode.o ioctl.o mballoc.o migrate.o \
mmp.o move_extent.o namei.o page-io.o readpage.o resize.o \
super.o symlink.o sysfs.o xattr.o xattr_trusted.o xattr_user.o
ext4-$(CONFIG_EXT4_FS_POSIX_ACL) += acl.o
ext4-$(CONFIG_EXT4_FS_SECURITY) += xattr_security.o

722
fs/ext4/fsmap.c Normal file
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@ -0,0 +1,722 @@
/*
* Copyright (C) 2017 Oracle. All Rights Reserved.
*
* Author: Darrick J. Wong <darrick.wong@oracle.com>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it would be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA.
*/
#include "ext4.h"
#include <linux/fsmap.h>
#include "fsmap.h"
#include "mballoc.h"
#include <linux/sort.h>
#include <linux/list_sort.h>
#include <trace/events/ext4.h>
/* Convert an ext4_fsmap to an fsmap. */
void ext4_fsmap_from_internal(struct super_block *sb, struct fsmap *dest,
struct ext4_fsmap *src)
{
dest->fmr_device = src->fmr_device;
dest->fmr_flags = src->fmr_flags;
dest->fmr_physical = src->fmr_physical << sb->s_blocksize_bits;
dest->fmr_owner = src->fmr_owner;
dest->fmr_offset = 0;
dest->fmr_length = src->fmr_length << sb->s_blocksize_bits;
dest->fmr_reserved[0] = 0;
dest->fmr_reserved[1] = 0;
dest->fmr_reserved[2] = 0;
}
/* Convert an fsmap to an ext4_fsmap. */
void ext4_fsmap_to_internal(struct super_block *sb, struct ext4_fsmap *dest,
struct fsmap *src)
{
dest->fmr_device = src->fmr_device;
dest->fmr_flags = src->fmr_flags;
dest->fmr_physical = src->fmr_physical >> sb->s_blocksize_bits;
dest->fmr_owner = src->fmr_owner;
dest->fmr_length = src->fmr_length >> sb->s_blocksize_bits;
}
/* getfsmap query state */
struct ext4_getfsmap_info {
struct ext4_fsmap_head *gfi_head;
ext4_fsmap_format_t gfi_formatter; /* formatting fn */
void *gfi_format_arg;/* format buffer */
ext4_fsblk_t gfi_next_fsblk; /* next fsblock we expect */
u32 gfi_dev; /* device id */
ext4_group_t gfi_agno; /* bg number, if applicable */
struct ext4_fsmap gfi_low; /* low rmap key */
struct ext4_fsmap gfi_high; /* high rmap key */
struct ext4_fsmap gfi_lastfree; /* free ext at end of last bg */
struct list_head gfi_meta_list; /* fixed metadata list */
bool gfi_last; /* last extent? */
};
/* Associate a device with a getfsmap handler. */
struct ext4_getfsmap_dev {
int (*gfd_fn)(struct super_block *sb,
struct ext4_fsmap *keys,
struct ext4_getfsmap_info *info);
u32 gfd_dev;
};
/* Compare two getfsmap device handlers. */
static int ext4_getfsmap_dev_compare(const void *p1, const void *p2)
{
const struct ext4_getfsmap_dev *d1 = p1;
const struct ext4_getfsmap_dev *d2 = p2;
return d1->gfd_dev - d2->gfd_dev;
}
/* Compare a record against our starting point */
static bool ext4_getfsmap_rec_before_low_key(struct ext4_getfsmap_info *info,
struct ext4_fsmap *rec)
{
return rec->fmr_physical < info->gfi_low.fmr_physical;
}
/*
* Format a reverse mapping for getfsmap, having translated rm_startblock
* into the appropriate daddr units.
*/
static int ext4_getfsmap_helper(struct super_block *sb,
struct ext4_getfsmap_info *info,
struct ext4_fsmap *rec)
{
struct ext4_fsmap fmr;
struct ext4_sb_info *sbi = EXT4_SB(sb);
ext4_fsblk_t rec_fsblk = rec->fmr_physical;
ext4_group_t agno;
ext4_grpblk_t cno;
int error;
if (fatal_signal_pending(current))
return -EINTR;
/*
* Filter out records that start before our startpoint, if the
* caller requested that.
*/
if (ext4_getfsmap_rec_before_low_key(info, rec)) {
rec_fsblk += rec->fmr_length;
if (info->gfi_next_fsblk < rec_fsblk)
info->gfi_next_fsblk = rec_fsblk;
return EXT4_QUERY_RANGE_CONTINUE;
}
/* Are we just counting mappings? */
if (info->gfi_head->fmh_count == 0) {
if (rec_fsblk > info->gfi_next_fsblk)
info->gfi_head->fmh_entries++;
if (info->gfi_last)
return EXT4_QUERY_RANGE_CONTINUE;
info->gfi_head->fmh_entries++;
rec_fsblk += rec->fmr_length;
if (info->gfi_next_fsblk < rec_fsblk)
info->gfi_next_fsblk = rec_fsblk;
return EXT4_QUERY_RANGE_CONTINUE;
}
/*
* If the record starts past the last physical block we saw,
* then we've found a gap. Report the gap as being owned by
* whatever the caller specified is the missing owner.
*/
if (rec_fsblk > info->gfi_next_fsblk) {
if (info->gfi_head->fmh_entries >= info->gfi_head->fmh_count)
return EXT4_QUERY_RANGE_ABORT;
ext4_get_group_no_and_offset(sb, info->gfi_next_fsblk,
&agno, &cno);
trace_ext4_fsmap_mapping(sb, info->gfi_dev, agno,
EXT4_C2B(sbi, cno),
rec_fsblk - info->gfi_next_fsblk,
EXT4_FMR_OWN_UNKNOWN);
fmr.fmr_device = info->gfi_dev;
fmr.fmr_physical = info->gfi_next_fsblk;
fmr.fmr_owner = EXT4_FMR_OWN_UNKNOWN;
fmr.fmr_length = rec_fsblk - info->gfi_next_fsblk;
fmr.fmr_flags = FMR_OF_SPECIAL_OWNER;
error = info->gfi_formatter(&fmr, info->gfi_format_arg);
if (error)
return error;
info->gfi_head->fmh_entries++;
}
if (info->gfi_last)
goto out;
/* Fill out the extent we found */
if (info->gfi_head->fmh_entries >= info->gfi_head->fmh_count)
return EXT4_QUERY_RANGE_ABORT;
ext4_get_group_no_and_offset(sb, rec_fsblk, &agno, &cno);
trace_ext4_fsmap_mapping(sb, info->gfi_dev, agno, EXT4_C2B(sbi, cno),
rec->fmr_length, rec->fmr_owner);
fmr.fmr_device = info->gfi_dev;
fmr.fmr_physical = rec_fsblk;
fmr.fmr_owner = rec->fmr_owner;
fmr.fmr_flags = FMR_OF_SPECIAL_OWNER;
fmr.fmr_length = rec->fmr_length;
error = info->gfi_formatter(&fmr, info->gfi_format_arg);
if (error)
return error;
info->gfi_head->fmh_entries++;
out:
rec_fsblk += rec->fmr_length;
if (info->gfi_next_fsblk < rec_fsblk)
info->gfi_next_fsblk = rec_fsblk;
return EXT4_QUERY_RANGE_CONTINUE;
}
static inline ext4_fsblk_t ext4_fsmap_next_pblk(struct ext4_fsmap *fmr)
{
return fmr->fmr_physical + fmr->fmr_length;
}
/* Transform a blockgroup's free record into a fsmap */
static int ext4_getfsmap_datadev_helper(struct super_block *sb,
ext4_group_t agno, ext4_grpblk_t start,
ext4_grpblk_t len, void *priv)
{
struct ext4_fsmap irec;
struct ext4_getfsmap_info *info = priv;
struct ext4_fsmap *p;
struct ext4_fsmap *tmp;
struct ext4_sb_info *sbi = EXT4_SB(sb);
ext4_fsblk_t fsb;
ext4_fsblk_t fslen;
int error;
fsb = (EXT4_C2B(sbi, start) + ext4_group_first_block_no(sb, agno));
fslen = EXT4_C2B(sbi, len);
/* If the retained free extent record is set... */
if (info->gfi_lastfree.fmr_owner) {
/* ...and abuts this one, lengthen it and return. */
if (ext4_fsmap_next_pblk(&info->gfi_lastfree) == fsb) {
info->gfi_lastfree.fmr_length += fslen;
return 0;
}
/*
* There's a gap between the two free extents; emit the
* retained extent prior to merging the meta_list.
*/
error = ext4_getfsmap_helper(sb, info, &info->gfi_lastfree);
if (error)
return error;
info->gfi_lastfree.fmr_owner = 0;
}
/* Merge in any relevant extents from the meta_list */
list_for_each_entry_safe(p, tmp, &info->gfi_meta_list, fmr_list) {
if (p->fmr_physical + p->fmr_length <= info->gfi_next_fsblk) {
list_del(&p->fmr_list);
kfree(p);
} else if (p->fmr_physical < fsb) {
error = ext4_getfsmap_helper(sb, info, p);
if (error)
return error;
list_del(&p->fmr_list);
kfree(p);
}
}
irec.fmr_device = 0;
irec.fmr_physical = fsb;
irec.fmr_length = fslen;
irec.fmr_owner = EXT4_FMR_OWN_FREE;
irec.fmr_flags = 0;
/* If this is a free extent at the end of a bg, buffer it. */
if (ext4_fsmap_next_pblk(&irec) ==
ext4_group_first_block_no(sb, agno + 1)) {
info->gfi_lastfree = irec;
return 0;
}
/* Otherwise, emit it */
return ext4_getfsmap_helper(sb, info, &irec);
}
/* Execute a getfsmap query against the log device. */
static int ext4_getfsmap_logdev(struct super_block *sb, struct ext4_fsmap *keys,
struct ext4_getfsmap_info *info)
{
journal_t *journal = EXT4_SB(sb)->s_journal;
struct ext4_fsmap irec;
/* Set up search keys */
info->gfi_low = keys[0];
info->gfi_low.fmr_length = 0;
memset(&info->gfi_high, 0xFF, sizeof(info->gfi_high));
trace_ext4_fsmap_low_key(sb, info->gfi_dev, 0,
info->gfi_low.fmr_physical,
info->gfi_low.fmr_length,
info->gfi_low.fmr_owner);
trace_ext4_fsmap_high_key(sb, info->gfi_dev, 0,
info->gfi_high.fmr_physical,
info->gfi_high.fmr_length,
info->gfi_high.fmr_owner);
if (keys[0].fmr_physical > 0)
return 0;
/* Fabricate an rmap entry for the external log device. */
irec.fmr_physical = journal->j_blk_offset;
irec.fmr_length = journal->j_maxlen;
irec.fmr_owner = EXT4_FMR_OWN_LOG;
irec.fmr_flags = 0;
return ext4_getfsmap_helper(sb, info, &irec);
}
/* Helper to fill out an ext4_fsmap. */
static inline int ext4_getfsmap_fill(struct list_head *meta_list,
ext4_fsblk_t fsb, ext4_fsblk_t len,
uint64_t owner)
{
struct ext4_fsmap *fsm;
fsm = kmalloc(sizeof(*fsm), GFP_NOFS);
if (!fsm)
return -ENOMEM;
fsm->fmr_device = 0;
fsm->fmr_flags = 0;
fsm->fmr_physical = fsb;
fsm->fmr_owner = owner;
fsm->fmr_length = len;
list_add_tail(&fsm->fmr_list, meta_list);
return 0;
}
/*
* This function returns the number of file system metadata blocks at
* the beginning of a block group, including the reserved gdt blocks.
*/
static unsigned int ext4_getfsmap_find_sb(struct super_block *sb,
ext4_group_t agno,
struct list_head *meta_list)
{
struct ext4_sb_info *sbi = EXT4_SB(sb);
ext4_fsblk_t fsb = ext4_group_first_block_no(sb, agno);
ext4_fsblk_t len;
unsigned long first_meta_bg = le32_to_cpu(sbi->s_es->s_first_meta_bg);
unsigned long metagroup = agno / EXT4_DESC_PER_BLOCK(sb);
int error;
/* Record the superblock. */
if (ext4_bg_has_super(sb, agno)) {
error = ext4_getfsmap_fill(meta_list, fsb, 1, EXT4_FMR_OWN_FS);
if (error)
return error;
fsb++;
}
/* Record the group descriptors. */
len = ext4_bg_num_gdb(sb, agno);
if (!len)
return 0;
error = ext4_getfsmap_fill(meta_list, fsb, len,
EXT4_FMR_OWN_GDT);
if (error)
return error;
fsb += len;
/* Reserved GDT blocks */
if (!ext4_has_feature_meta_bg(sb) || metagroup < first_meta_bg) {
len = le16_to_cpu(sbi->s_es->s_reserved_gdt_blocks);
error = ext4_getfsmap_fill(meta_list, fsb, len,
EXT4_FMR_OWN_RESV_GDT);
if (error)
return error;
}
return 0;
}
/* Compare two fsmap items. */
static int ext4_getfsmap_compare(void *priv,
struct list_head *a,
struct list_head *b)
{
struct ext4_fsmap *fa;
struct ext4_fsmap *fb;
fa = container_of(a, struct ext4_fsmap, fmr_list);
fb = container_of(b, struct ext4_fsmap, fmr_list);
if (fa->fmr_physical < fb->fmr_physical)
return -1;
else if (fa->fmr_physical > fb->fmr_physical)
return 1;
return 0;
}
/* Merge adjacent extents of fixed metadata. */
static void ext4_getfsmap_merge_fixed_metadata(struct list_head *meta_list)
{
struct ext4_fsmap *p;
struct ext4_fsmap *prev = NULL;
struct ext4_fsmap *tmp;
list_for_each_entry_safe(p, tmp, meta_list, fmr_list) {
if (!prev) {
prev = p;
continue;
}
if (prev->fmr_owner == p->fmr_owner &&
prev->fmr_physical + prev->fmr_length == p->fmr_physical) {
prev->fmr_length += p->fmr_length;
list_del(&p->fmr_list);
kfree(p);
} else
prev = p;
}
}
/* Free a list of fixed metadata. */
static void ext4_getfsmap_free_fixed_metadata(struct list_head *meta_list)
{
struct ext4_fsmap *p;
struct ext4_fsmap *tmp;
list_for_each_entry_safe(p, tmp, meta_list, fmr_list) {
list_del(&p->fmr_list);
kfree(p);
}
}
/* Find all the fixed metadata in the filesystem. */
int ext4_getfsmap_find_fixed_metadata(struct super_block *sb,
struct list_head *meta_list)
{
struct ext4_group_desc *gdp;
ext4_group_t agno;
int error;
INIT_LIST_HEAD(meta_list);
/* Collect everything. */
for (agno = 0; agno < EXT4_SB(sb)->s_groups_count; agno++) {
gdp = ext4_get_group_desc(sb, agno, NULL);
if (!gdp) {
error = -EFSCORRUPTED;
goto err;
}
/* Superblock & GDT */
error = ext4_getfsmap_find_sb(sb, agno, meta_list);
if (error)
goto err;
/* Block bitmap */
error = ext4_getfsmap_fill(meta_list,
ext4_block_bitmap(sb, gdp), 1,
EXT4_FMR_OWN_BLKBM);
if (error)
goto err;
/* Inode bitmap */
error = ext4_getfsmap_fill(meta_list,
ext4_inode_bitmap(sb, gdp), 1,
EXT4_FMR_OWN_INOBM);
if (error)
goto err;
/* Inodes */
error = ext4_getfsmap_fill(meta_list,
ext4_inode_table(sb, gdp),
EXT4_SB(sb)->s_itb_per_group,
EXT4_FMR_OWN_INODES);
if (error)
goto err;
}
/* Sort the list */
list_sort(NULL, meta_list, ext4_getfsmap_compare);
/* Merge adjacent extents */
ext4_getfsmap_merge_fixed_metadata(meta_list);
return 0;
err:
ext4_getfsmap_free_fixed_metadata(meta_list);
return error;
}
/* Execute a getfsmap query against the buddy bitmaps */
static int ext4_getfsmap_datadev(struct super_block *sb,
struct ext4_fsmap *keys,
struct ext4_getfsmap_info *info)
{
struct ext4_sb_info *sbi = EXT4_SB(sb);
ext4_fsblk_t start_fsb;
ext4_fsblk_t end_fsb;
ext4_fsblk_t eofs;
ext4_group_t start_ag;
ext4_group_t end_ag;
ext4_grpblk_t first_cluster;
ext4_grpblk_t last_cluster;
int error = 0;
eofs = ext4_blocks_count(sbi->s_es);
if (keys[0].fmr_physical >= eofs)
return 0;
if (keys[1].fmr_physical >= eofs)
keys[1].fmr_physical = eofs - 1;
start_fsb = keys[0].fmr_physical;
end_fsb = keys[1].fmr_physical;
/* Determine first and last group to examine based on start and end */
ext4_get_group_no_and_offset(sb, start_fsb, &start_ag, &first_cluster);
ext4_get_group_no_and_offset(sb, end_fsb, &end_ag, &last_cluster);
/*
* Convert the fsmap low/high keys to bg based keys. Initialize
* low to the fsmap low key and max out the high key to the end
* of the bg.
*/
info->gfi_low = keys[0];
info->gfi_low.fmr_physical = EXT4_C2B(sbi, first_cluster);
info->gfi_low.fmr_length = 0;
memset(&info->gfi_high, 0xFF, sizeof(info->gfi_high));
/* Assemble a list of all the fixed-location metadata. */
error = ext4_getfsmap_find_fixed_metadata(sb, &info->gfi_meta_list);
if (error)
goto err;
/* Query each bg */
for (info->gfi_agno = start_ag;
info->gfi_agno <= end_ag;
info->gfi_agno++) {
/*
* Set the bg high key from the fsmap high key if this
* is the last bg that we're querying.
*/
if (info->gfi_agno == end_ag) {
info->gfi_high = keys[1];
info->gfi_high.fmr_physical = EXT4_C2B(sbi,
last_cluster);
info->gfi_high.fmr_length = 0;
}
trace_ext4_fsmap_low_key(sb, info->gfi_dev, info->gfi_agno,
info->gfi_low.fmr_physical,
info->gfi_low.fmr_length,
info->gfi_low.fmr_owner);
trace_ext4_fsmap_high_key(sb, info->gfi_dev, info->gfi_agno,
info->gfi_high.fmr_physical,
info->gfi_high.fmr_length,
info->gfi_high.fmr_owner);
error = ext4_mballoc_query_range(sb, info->gfi_agno,
EXT4_B2C(sbi, info->gfi_low.fmr_physical),
EXT4_B2C(sbi, info->gfi_high.fmr_physical),
ext4_getfsmap_datadev_helper, info);
if (error)
goto err;
/*
* Set the bg low key to the start of the bg prior to
* moving on to the next bg.
*/
if (info->gfi_agno == start_ag)
memset(&info->gfi_low, 0, sizeof(info->gfi_low));
}
/* Do we have a retained free extent? */
if (info->gfi_lastfree.fmr_owner) {
error = ext4_getfsmap_helper(sb, info, &info->gfi_lastfree);
if (error)
goto err;
}
/* Report any gaps at the end of the bg */
info->gfi_last = true;
error = ext4_getfsmap_datadev_helper(sb, end_ag, last_cluster, 0, info);
if (error)
goto err;
err:
ext4_getfsmap_free_fixed_metadata(&info->gfi_meta_list);
return error;
}
/* Do we recognize the device? */
static bool ext4_getfsmap_is_valid_device(struct super_block *sb,
struct ext4_fsmap *fm)
{
if (fm->fmr_device == 0 || fm->fmr_device == UINT_MAX ||
fm->fmr_device == new_encode_dev(sb->s_bdev->bd_dev))
return true;
if (EXT4_SB(sb)->journal_bdev &&
fm->fmr_device == new_encode_dev(EXT4_SB(sb)->journal_bdev->bd_dev))
return true;
return false;
}
/* Ensure that the low key is less than the high key. */
static bool ext4_getfsmap_check_keys(struct ext4_fsmap *low_key,
struct ext4_fsmap *high_key)
{
if (low_key->fmr_device > high_key->fmr_device)
return false;
if (low_key->fmr_device < high_key->fmr_device)
return true;
if (low_key->fmr_physical > high_key->fmr_physical)
return false;
if (low_key->fmr_physical < high_key->fmr_physical)
return true;
if (low_key->fmr_owner > high_key->fmr_owner)
return false;
if (low_key->fmr_owner < high_key->fmr_owner)
return true;
return false;
}
#define EXT4_GETFSMAP_DEVS 2
/*
* Get filesystem's extents as described in head, and format for
* output. Calls formatter to fill the user's buffer until all
* extents are mapped, until the passed-in head->fmh_count slots have
* been filled, or until the formatter short-circuits the loop, if it
* is tracking filled-in extents on its own.
*
* Key to Confusion
* ----------------
* There are multiple levels of keys and counters at work here:
* _fsmap_head.fmh_keys -- low and high fsmap keys passed in;
* these reflect fs-wide block addrs.
* dkeys -- fmh_keys used to query each device;
* these are fmh_keys but w/ the low key
* bumped up by fmr_length.
* _getfsmap_info.gfi_next_fsblk-- next fs block we expect to see; this
* is how we detect gaps in the fsmap
* records and report them.
* _getfsmap_info.gfi_low/high -- per-bg low/high keys computed from
* dkeys; used to query the free space.
*/
int ext4_getfsmap(struct super_block *sb, struct ext4_fsmap_head *head,
ext4_fsmap_format_t formatter, void *arg)
{
struct ext4_fsmap dkeys[2]; /* per-dev keys */
struct ext4_getfsmap_dev handlers[EXT4_GETFSMAP_DEVS];
struct ext4_getfsmap_info info = {0};
int i;
int error = 0;
if (head->fmh_iflags & ~FMH_IF_VALID)
return -EINVAL;
if (!ext4_getfsmap_is_valid_device(sb, &head->fmh_keys[0]) ||
!ext4_getfsmap_is_valid_device(sb, &head->fmh_keys[1]))
return -EINVAL;
head->fmh_entries = 0;
/* Set up our device handlers. */
memset(handlers, 0, sizeof(handlers));
handlers[0].gfd_dev = new_encode_dev(sb->s_bdev->bd_dev);
handlers[0].gfd_fn = ext4_getfsmap_datadev;
if (EXT4_SB(sb)->journal_bdev) {
handlers[1].gfd_dev = new_encode_dev(
EXT4_SB(sb)->journal_bdev->bd_dev);
handlers[1].gfd_fn = ext4_getfsmap_logdev;
}
sort(handlers, EXT4_GETFSMAP_DEVS, sizeof(struct ext4_getfsmap_dev),
ext4_getfsmap_dev_compare, NULL);
/*
* To continue where we left off, we allow userspace to use the
* last mapping from a previous call as the low key of the next.
* This is identified by a non-zero length in the low key. We
* have to increment the low key in this scenario to ensure we
* don't return the same mapping again, and instead return the
* very next mapping.
*
* Bump the physical offset as there can be no other mapping for
* the same physical block range.
*/
dkeys[0] = head->fmh_keys[0];
dkeys[0].fmr_physical += dkeys[0].fmr_length;
dkeys[0].fmr_owner = 0;
dkeys[0].fmr_length = 0;
memset(&dkeys[1], 0xFF, sizeof(struct ext4_fsmap));
if (!ext4_getfsmap_check_keys(dkeys, &head->fmh_keys[1]))
return -EINVAL;
info.gfi_next_fsblk = head->fmh_keys[0].fmr_physical +
head->fmh_keys[0].fmr_length;
info.gfi_formatter = formatter;
info.gfi_format_arg = arg;
info.gfi_head = head;
/* For each device we support... */
for (i = 0; i < EXT4_GETFSMAP_DEVS; i++) {
/* Is this device within the range the user asked for? */
if (!handlers[i].gfd_fn)
continue;
if (head->fmh_keys[0].fmr_device > handlers[i].gfd_dev)
continue;
if (head->fmh_keys[1].fmr_device < handlers[i].gfd_dev)
break;
/*
* If this device number matches the high key, we have
* to pass the high key to the handler to limit the
* query results. If the device number exceeds the
* low key, zero out the low key so that we get
* everything from the beginning.
*/
if (handlers[i].gfd_dev == head->fmh_keys[1].fmr_device)
dkeys[1] = head->fmh_keys[1];
if (handlers[i].gfd_dev > head->fmh_keys[0].fmr_device)
memset(&dkeys[0], 0, sizeof(struct ext4_fsmap));
info.gfi_dev = handlers[i].gfd_dev;
info.gfi_last = false;
info.gfi_agno = -1;
error = handlers[i].gfd_fn(sb, dkeys, &info);
if (error)
break;
info.gfi_next_fsblk = 0;
}
head->fmh_oflags = FMH_OF_DEV_T;
return error;
}

69
fs/ext4/fsmap.h Normal file
View File

@ -0,0 +1,69 @@
/*
* Copyright (C) 2017 Oracle. All Rights Reserved.
*
* Author: Darrick J. Wong <darrick.wong@oracle.com>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This program is distributed in the hope that it would be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA.
*/
#ifndef __EXT4_FSMAP_H__
#define __EXT4_FSMAP_H__
struct fsmap;
/* internal fsmap representation */
struct ext4_fsmap {
struct list_head fmr_list;
dev_t fmr_device; /* device id */
uint32_t fmr_flags; /* mapping flags */
uint64_t fmr_physical; /* device offset of segment */
uint64_t fmr_owner; /* owner id */
uint64_t fmr_length; /* length of segment, blocks */
};
struct ext4_fsmap_head {
uint32_t fmh_iflags; /* control flags */
uint32_t fmh_oflags; /* output flags */
unsigned int fmh_count; /* # of entries in array incl. input */
unsigned int fmh_entries; /* # of entries filled in (output). */
struct ext4_fsmap fmh_keys[2]; /* low and high keys */
};
void ext4_fsmap_from_internal(struct super_block *sb, struct fsmap *dest,
struct ext4_fsmap *src);
void ext4_fsmap_to_internal(struct super_block *sb, struct ext4_fsmap *dest,
struct fsmap *src);
/* fsmap to userspace formatter - copy to user & advance pointer */
typedef int (*ext4_fsmap_format_t)(struct ext4_fsmap *, void *);
int ext4_getfsmap(struct super_block *sb, struct ext4_fsmap_head *head,
ext4_fsmap_format_t formatter, void *arg);
#define EXT4_QUERY_RANGE_ABORT 1
#define EXT4_QUERY_RANGE_CONTINUE 0
/* fmr_owner special values for FS_IOC_GETFSMAP; some share w/ XFS */
#define EXT4_FMR_OWN_FREE FMR_OWN_FREE /* free space */
#define EXT4_FMR_OWN_UNKNOWN FMR_OWN_UNKNOWN /* unknown owner */
#define EXT4_FMR_OWN_FS FMR_OWNER('X', 1) /* static fs metadata */
#define EXT4_FMR_OWN_LOG FMR_OWNER('X', 2) /* journalling log */
#define EXT4_FMR_OWN_INODES FMR_OWNER('X', 5) /* inodes */
#define EXT4_FMR_OWN_GDT FMR_OWNER('f', 1) /* group descriptors */
#define EXT4_FMR_OWN_RESV_GDT FMR_OWNER('f', 2) /* reserved gdt blocks */
#define EXT4_FMR_OWN_BLKBM FMR_OWNER('f', 3) /* inode bitmap */
#define EXT4_FMR_OWN_INOBM FMR_OWNER('f', 4) /* block bitmap */
#endif /* __EXT4_FSMAP_H__ */

90
fs/ext4/ioctl.c
View File

@ -19,6 +19,9 @@
#include <linux/delay.h>
#include "ext4_jbd2.h"
#include "ext4.h"
#include <linux/fsmap.h>
#include "fsmap.h"
#include <trace/events/ext4.h>
/**
* Swap memory between @a and @b for @len bytes.
@ -489,6 +492,90 @@ int ext4_shutdown(struct super_block *sb, unsigned long arg)
return 0;
}
struct getfsmap_info {
struct super_block *gi_sb;
struct fsmap_head __user *gi_data;
unsigned int gi_idx;
__u32 gi_last_flags;
};
static int ext4_getfsmap_format(struct ext4_fsmap *xfm, void *priv)
{
struct getfsmap_info *info = priv;
struct fsmap fm;
trace_ext4_getfsmap_mapping(info->gi_sb, xfm);
info->gi_last_flags = xfm->fmr_flags;
ext4_fsmap_from_internal(info->gi_sb, &fm, xfm);
if (copy_to_user(&info->gi_data->fmh_recs[info->gi_idx++], &fm,
sizeof(struct fsmap)))
return -EFAULT;
return 0;
}
static int ext4_ioc_getfsmap(struct super_block *sb,
struct fsmap_head __user *arg)
{
struct getfsmap_info info = {0};
struct ext4_fsmap_head xhead = {0};
struct fsmap_head head;
bool aborted = false;
int error;
if (copy_from_user(&head, arg, sizeof(struct fsmap_head)))
return -EFAULT;
if (memchr_inv(head.fmh_reserved, 0, sizeof(head.fmh_reserved)) ||
memchr_inv(head.fmh_keys[0].fmr_reserved, 0,
sizeof(head.fmh_keys[0].fmr_reserved)) ||
memchr_inv(head.fmh_keys[1].fmr_reserved, 0,
sizeof(head.fmh_keys[1].fmr_reserved)))
return -EINVAL;
/*
* ext4 doesn't report file extents at all, so the only valid
* file offsets are the magic ones (all zeroes or all ones).
*/
if (head.fmh_keys[0].fmr_offset ||
(head.fmh_keys[1].fmr_offset != 0 &&
head.fmh_keys[1].fmr_offset != -1ULL))
return -EINVAL;
xhead.fmh_iflags = head.fmh_iflags;
xhead.fmh_count = head.fmh_count;
ext4_fsmap_to_internal(sb, &xhead.fmh_keys[0], &head.fmh_keys[0]);
ext4_fsmap_to_internal(sb, &xhead.fmh_keys[1], &head.fmh_keys[1]);
trace_ext4_getfsmap_low_key(sb, &xhead.fmh_keys[0]);
trace_ext4_getfsmap_high_key(sb, &xhead.fmh_keys[1]);
info.gi_sb = sb;
info.gi_data = arg;
error = ext4_getfsmap(sb, &xhead, ext4_getfsmap_format, &info);
if (error == EXT4_QUERY_RANGE_ABORT) {
error = 0;
aborted = true;
} else if (error)
return error;
/* If we didn't abort, set the "last" flag in the last fmx */
if (!aborted && info.gi_idx) {
info.gi_last_flags |= FMR_OF_LAST;
if (copy_to_user(&info.gi_data->fmh_recs[info.gi_idx - 1].fmr_flags,
&info.gi_last_flags,
sizeof(info.gi_last_flags)))
return -EFAULT;
}
/* copy back header */
head.fmh_entries = xhead.fmh_entries;
head.fmh_oflags = xhead.fmh_oflags;
if (copy_to_user(arg, &head, sizeof(struct fsmap_head)))
return -EFAULT;
return 0;
}
long ext4_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
{
struct inode *inode = file_inode(filp);
@ -499,6 +586,8 @@ long ext4_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
ext4_debug("cmd = %u, arg = %lu\n", cmd, arg);
switch (cmd) {
case FS_IOC_GETFSMAP:
return ext4_ioc_getfsmap(sb, (void __user *)arg);
case EXT4_IOC_GETFLAGS:
ext4_get_inode_flags(ei);
flags = ei->i_flags & EXT4_FL_USER_VISIBLE;
@ -1009,6 +1098,7 @@ long ext4_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
case EXT4_IOC_GET_ENCRYPTION_PWSALT:
case EXT4_IOC_GET_ENCRYPTION_POLICY:
case EXT4_IOC_SHUTDOWN:
case FS_IOC_GETFSMAP:
break;
default:
return -ENOIOCTLCMD;

49
fs/ext4/mballoc.c
View File

@ -5277,3 +5277,52 @@ 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;
}

17
fs/ext4/mballoc.h
View File

@ -199,4 +199,21 @@ static inline ext4_fsblk_t ext4_grp_offs_to_block(struct super_block *sb,
return ext4_group_first_block_no(sb, fex->fe_group) +
(fex->fe_start << EXT4_SB(sb)->s_cluster_bits);
}
typedef int (*ext4_mballoc_query_range_fn)(
struct super_block *sb,
ext4_group_t agno,
ext4_grpblk_t start,
ext4_grpblk_t len,
void *priv);
int
ext4_mballoc_query_range(
struct super_block *sb,
ext4_group_t agno,
ext4_grpblk_t start,
ext4_grpblk_t end,
ext4_mballoc_query_range_fn formatter,
void *priv);
#endif

1
fs/ext4/super.c
View File

@ -49,6 +49,7 @@
#include "xattr.h"
#include "acl.h"
#include "mballoc.h"
#include "fsmap.h"
#define CREATE_TRACE_POINTS
#include <trace/events/ext4.h>

74
include/trace/events/ext4.h
View File

@ -15,6 +15,7 @@ struct ext4_inode_info;
struct mpage_da_data;
struct ext4_map_blocks;
struct extent_status;
struct ext4_fsmap;
#define EXT4_I(inode) (container_of(inode, struct ext4_inode_info, vfs_inode))
@ -2529,6 +2530,79 @@ TRACE_EVENT(ext4_es_shrink,
__entry->scan_time, __entry->nr_skipped, __entry->retried)
);
/* fsmap traces */
DECLARE_EVENT_CLASS(ext4_fsmap_class,
TP_PROTO(struct super_block *sb, u32 keydev, u32 agno, u64 bno, u64 len,
u64 owner),
TP_ARGS(sb, keydev, agno, bno, len, owner),
TP_STRUCT__entry(
__field(dev_t, dev)
__field(dev_t, keydev)
__field(u32, agno)
__field(u64, bno)
__field(u64, len)
__field(u64, owner)
),
TP_fast_assign(
__entry->dev = sb->s_bdev->bd_dev;
__entry->keydev = new_decode_dev(keydev);
__entry->agno = agno;
__entry->bno = bno;
__entry->len = len;
__entry->owner = owner;
),
TP_printk("dev %d:%d keydev %d:%d agno %u bno %llu len %llu owner %lld\n",
MAJOR(__entry->dev), MINOR(__entry->dev),
MAJOR(__entry->keydev), MINOR(__entry->keydev),
__entry->agno,
__entry->bno,
__entry->len,
__entry->owner)
)
#define DEFINE_FSMAP_EVENT(name) \
DEFINE_EVENT(ext4_fsmap_class, name, \
TP_PROTO(struct super_block *sb, u32 keydev, u32 agno, u64 bno, u64 len, \
u64 owner), \
TP_ARGS(sb, keydev, agno, bno, len, owner))
DEFINE_FSMAP_EVENT(ext4_fsmap_low_key);
DEFINE_FSMAP_EVENT(ext4_fsmap_high_key);
DEFINE_FSMAP_EVENT(ext4_fsmap_mapping);
DECLARE_EVENT_CLASS(ext4_getfsmap_class,
TP_PROTO(struct super_block *sb, struct ext4_fsmap *fsmap),
TP_ARGS(sb, fsmap),
TP_STRUCT__entry(
__field(dev_t, dev)
__field(dev_t, keydev)
__field(u64, block)
__field(u64, len)
__field(u64, owner)
__field(u64, flags)
),
TP_fast_assign(
__entry->dev = sb->s_bdev->bd_dev;
__entry->keydev = new_decode_dev(fsmap->fmr_device);
__entry->block = fsmap->fmr_physical;
__entry->len = fsmap->fmr_length;
__entry->owner = fsmap->fmr_owner;
__entry->flags = fsmap->fmr_flags;
),
TP_printk("dev %d:%d keydev %d:%d block %llu len %llu owner %lld flags 0x%llx\n",
MAJOR(__entry->dev), MINOR(__entry->dev),
MAJOR(__entry->keydev), MINOR(__entry->keydev),
__entry->block,
__entry->len,
__entry->owner,
__entry->flags)
)
#define DEFINE_GETFSMAP_EVENT(name) \
DEFINE_EVENT(ext4_getfsmap_class, name, \
TP_PROTO(struct super_block *sb, struct ext4_fsmap *fsmap), \
TP_ARGS(sb, fsmap))
DEFINE_GETFSMAP_EVENT(ext4_getfsmap_low_key);
DEFINE_GETFSMAP_EVENT(ext4_getfsmap_high_key);
DEFINE_GETFSMAP_EVENT(ext4_getfsmap_mapping);
#endif /* _TRACE_EXT4_H */
/* This part must be outside protection */