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linux/fs/ext4/move_extent.c
Lukas Czerner f17722f917 ext4: Fix max file size and logical block counting of extent format file 
Kazuya Mio reported that he was able to hit BUG_ON(next == lblock)
in ext4_ext_put_gap_in_cache() while creating a sparse file in extent
format and fill the tail of file up to its end. We will hit the BUG_ON
when we write the last block (2^32-1) into the sparse file.

The root cause of the problem lies in the fact that we specifically set
s_maxbytes so that block at s_maxbytes fit into on-disk extent format,
which is 32 bit long. However, we are not storing start and end block
number, but rather start block number and length in blocks. It means
that in order to cover extent from 0 to EXT_MAX_BLOCK we need
EXT_MAX_BLOCK+1 to fit into len (because we counting block 0 as well) -
and it does not.

The only way to fix it without changing the meaning of the struct
ext4_extent members is, as Kazuya Mio suggested, to lower s_maxbytes
by one fs block so we can cover the whole extent we can get by the
on-disk extent format.

Also in many places EXT_MAX_BLOCK is used as length instead of maximum
logical block number as the name suggests, it is all a bit messy. So
this commit renames it to EXT_MAX_BLOCKS and change its usage in some
places to actually be maximum number of blocks in the extent.

The bug which this commit fixes can be reproduced as follows:

 dd if=/dev/zero of=/mnt/mp1/file bs=<blocksize> count=1 seek=$((2**32-2))
 sync
 dd if=/dev/zero of=/mnt/mp1/file bs=<blocksize> count=1 seek=$((2**32-1))

Reported-by: Kazuya Mio <k-mio@sx.jp.nec.com>
Signed-off-by: Lukas Czerner <lczerner@redhat.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2011-06-06 00:05:17 -04:00

1425 lines
41 KiB
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/*
* Copyright (c) 2008,2009 NEC Software Tohoku, Ltd.
* Written by Takashi Sato <t-sato@yk.jp.nec.com>
* Akira Fujita <a-fujita@rs.jp.nec.com>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of version 2.1 of the GNU Lesser General Public License
* as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will 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.
*/
#include <linux/fs.h>
#include <linux/quotaops.h>
#include <linux/slab.h>
#include "ext4_jbd2.h"
#include "ext4_extents.h"
#include "ext4.h"
/**
* get_ext_path - Find an extent path for designated logical block number.
*
* @inode: an inode which is searched
* @lblock: logical block number to find an extent path
* @path: pointer to an extent path pointer (for output)
*
* ext4_ext_find_extent wrapper. Return 0 on success, or a negative error value
* on failure.
*/
static inline int
get_ext_path(struct inode *inode, ext4_lblk_t lblock,
struct ext4_ext_path **path)
{
int ret = 0;
*path = ext4_ext_find_extent(inode, lblock, *path);
if (IS_ERR(*path)) {
ret = PTR_ERR(*path);
*path = NULL;
} else if ((*path)[ext_depth(inode)].p_ext == NULL)
ret = -ENODATA;
return ret;
}
/**
* copy_extent_status - Copy the extent's initialization status
*
* @src: an extent for getting initialize status
* @dest: an extent to be set the status
*/
static void
copy_extent_status(struct ext4_extent *src, struct ext4_extent *dest)
{
if (ext4_ext_is_uninitialized(src))
ext4_ext_mark_uninitialized(dest);
else
dest->ee_len = cpu_to_le16(ext4_ext_get_actual_len(dest));
}
/**
* mext_next_extent - Search for the next extent and set it to "extent"
*
* @inode: inode which is searched
* @path: this will obtain data for the next extent
* @extent: pointer to the next extent we have just gotten
*
* Search the next extent in the array of ext4_ext_path structure (@path)
* and set it to ext4_extent structure (@extent). In addition, the member of
* @path (->p_ext) also points the next extent. Return 0 on success, 1 if
* ext4_ext_path structure refers to the last extent, or a negative error
* value on failure.
*/
static int
mext_next_extent(struct inode *inode, struct ext4_ext_path *path,
struct ext4_extent **extent)
{
struct ext4_extent_header *eh;
int ppos, leaf_ppos = path->p_depth;
ppos = leaf_ppos;
if (EXT_LAST_EXTENT(path[ppos].p_hdr) > path[ppos].p_ext) {
/* leaf block */
*extent = ++path[ppos].p_ext;
path[ppos].p_block = ext4_ext_pblock(path[ppos].p_ext);
return 0;
}
while (--ppos >= 0) {
if (EXT_LAST_INDEX(path[ppos].p_hdr) >
path[ppos].p_idx) {
int cur_ppos = ppos;
/* index block */
path[ppos].p_idx++;
path[ppos].p_block = ext4_idx_pblock(path[ppos].p_idx);
if (path[ppos+1].p_bh)
brelse(path[ppos+1].p_bh);
path[ppos+1].p_bh =
sb_bread(inode->i_sb, path[ppos].p_block);
if (!path[ppos+1].p_bh)
return -EIO;
path[ppos+1].p_hdr =
ext_block_hdr(path[ppos+1].p_bh);
/* Halfway index block */
while (++cur_ppos < leaf_ppos) {
path[cur_ppos].p_idx =
EXT_FIRST_INDEX(path[cur_ppos].p_hdr);
path[cur_ppos].p_block =
ext4_idx_pblock(path[cur_ppos].p_idx);
if (path[cur_ppos+1].p_bh)
brelse(path[cur_ppos+1].p_bh);
path[cur_ppos+1].p_bh = sb_bread(inode->i_sb,
path[cur_ppos].p_block);
if (!path[cur_ppos+1].p_bh)
return -EIO;
path[cur_ppos+1].p_hdr =
ext_block_hdr(path[cur_ppos+1].p_bh);
}
path[leaf_ppos].p_ext = *extent = NULL;
eh = path[leaf_ppos].p_hdr;
if (le16_to_cpu(eh->eh_entries) == 0)
/* empty leaf is found */
return -ENODATA;
/* leaf block */
path[leaf_ppos].p_ext = *extent =
EXT_FIRST_EXTENT(path[leaf_ppos].p_hdr);
path[leaf_ppos].p_block =
ext4_ext_pblock(path[leaf_ppos].p_ext);
return 0;
}
}
/* We found the last extent */
return 1;
}
/**
* mext_check_null_inode - NULL check for two inodes
*
* If inode1 or inode2 is NULL, return -EIO. Otherwise, return 0.
*/
static int
mext_check_null_inode(struct inode *inode1, struct inode *inode2,
const char *function, unsigned int line)
{
int ret = 0;
if (inode1 == NULL) {
__ext4_error(inode2->i_sb, function, line,
"Both inodes should not be NULL: "
"inode1 NULL inode2 %lu", inode2->i_ino);
ret = -EIO;
} else if (inode2 == NULL) {
__ext4_error(inode1->i_sb, function, line,
"Both inodes should not be NULL: "
"inode1 %lu inode2 NULL", inode1->i_ino);
ret = -EIO;
}
return ret;
}
/**
* double_down_write_data_sem - Acquire two inodes' write lock of i_data_sem
*
* @orig_inode: original inode structure
* @donor_inode: donor inode structure
* Acquire write lock of i_data_sem of the two inodes (orig and donor) by
* i_ino order.
*/
static void
double_down_write_data_sem(struct inode *orig_inode, struct inode *donor_inode)
{
struct inode *first = orig_inode, *second = donor_inode;
/*
* Use the inode number to provide the stable locking order instead
* of its address, because the C language doesn't guarantee you can
* compare pointers that don't come from the same array.
*/
if (donor_inode->i_ino < orig_inode->i_ino) {
first = donor_inode;
second = orig_inode;
}
down_write(&EXT4_I(first)->i_data_sem);
down_write_nested(&EXT4_I(second)->i_data_sem, SINGLE_DEPTH_NESTING);
}
/**
* double_up_write_data_sem - Release two inodes' write lock of i_data_sem
*
* @orig_inode: original inode structure to be released its lock first
* @donor_inode: donor inode structure to be released its lock second
* Release write lock of i_data_sem of two inodes (orig and donor).
*/
static void
double_up_write_data_sem(struct inode *orig_inode, struct inode *donor_inode)
{
up_write(&EXT4_I(orig_inode)->i_data_sem);
up_write(&EXT4_I(donor_inode)->i_data_sem);
}
/**
* mext_insert_across_blocks - Insert extents across leaf block
*
* @handle: journal handle
* @orig_inode: original inode
* @o_start: first original extent to be changed
* @o_end: last original extent to be changed
* @start_ext: first new extent to be inserted
* @new_ext: middle of new extent to be inserted
* @end_ext: last new extent to be inserted
*
* Allocate a new leaf block and insert extents into it. Return 0 on success,
* or a negative error value on failure.
*/
static int
mext_insert_across_blocks(handle_t *handle, struct inode *orig_inode,
struct ext4_extent *o_start, struct ext4_extent *o_end,
struct ext4_extent *start_ext, struct ext4_extent *new_ext,
struct ext4_extent *end_ext)
{
struct ext4_ext_path *orig_path = NULL;
ext4_lblk_t eblock = 0;
int new_flag = 0;
int end_flag = 0;
int err = 0;
if (start_ext->ee_len && new_ext->ee_len && end_ext->ee_len) {
if (o_start == o_end) {
/* start_ext new_ext end_ext
* donor |---------|-----------|--------|
* orig |------------------------------|
*/
end_flag = 1;
} else {
/* start_ext new_ext end_ext
* donor |---------|----------|---------|
* orig |---------------|--------------|
*/
o_end->ee_block = end_ext->ee_block;
o_end->ee_len = end_ext->ee_len;
ext4_ext_store_pblock(o_end, ext4_ext_pblock(end_ext));
}
o_start->ee_len = start_ext->ee_len;
eblock = le32_to_cpu(start_ext->ee_block);
new_flag = 1;
} else if (start_ext->ee_len && new_ext->ee_len &&
!end_ext->ee_len && o_start == o_end) {
/* start_ext new_ext
* donor |--------------|---------------|
* orig |------------------------------|
*/
o_start->ee_len = start_ext->ee_len;
eblock = le32_to_cpu(start_ext->ee_block);
new_flag = 1;
} else if (!start_ext->ee_len && new_ext->ee_len &&
end_ext->ee_len && o_start == o_end) {
/* new_ext end_ext
* donor |--------------|---------------|
* orig |------------------------------|
*/
o_end->ee_block = end_ext->ee_block;
o_end->ee_len = end_ext->ee_len;
ext4_ext_store_pblock(o_end, ext4_ext_pblock(end_ext));
/*
* Set 0 to the extent block if new_ext was
* the first block.
*/
if (new_ext->ee_block)
eblock = le32_to_cpu(new_ext->ee_block);
new_flag = 1;
} else {
ext4_debug("ext4 move extent: Unexpected insert case\n");
return -EIO;
}
if (new_flag) {
err = get_ext_path(orig_inode, eblock, &orig_path);
if (err)
goto out;
if (ext4_ext_insert_extent(handle, orig_inode,
orig_path, new_ext, 0))
goto out;
}
if (end_flag) {
err = get_ext_path(orig_inode,
le32_to_cpu(end_ext->ee_block) - 1, &orig_path);
if (err)
goto out;
if (ext4_ext_insert_extent(handle, orig_inode,
orig_path, end_ext, 0))
goto out;
}
out:
if (orig_path) {
ext4_ext_drop_refs(orig_path);
kfree(orig_path);
}
return err;
}
/**
* mext_insert_inside_block - Insert new extent to the extent block
*
* @o_start: first original extent to be moved
* @o_end: last original extent to be moved
* @start_ext: first new extent to be inserted
* @new_ext: middle of new extent to be inserted
* @end_ext: last new extent to be inserted
* @eh: extent header of target leaf block
* @range_to_move: used to decide how to insert extent
*
* Insert extents into the leaf block. The extent (@o_start) is overwritten
* by inserted extents.
*/
static void
mext_insert_inside_block(struct ext4_extent *o_start,
struct ext4_extent *o_end,
struct ext4_extent *start_ext,
struct ext4_extent *new_ext,
struct ext4_extent *end_ext,
struct ext4_extent_header *eh,
int range_to_move)
{
int i = 0;
unsigned long len;
/* Move the existing extents */
if (range_to_move && o_end < EXT_LAST_EXTENT(eh)) {
len = (unsigned long)(EXT_LAST_EXTENT(eh) + 1) -
(unsigned long)(o_end + 1);
memmove(o_end + 1 + range_to_move, o_end + 1, len);
}
/* Insert start entry */
if (start_ext->ee_len)
o_start[i++].ee_len = start_ext->ee_len;
/* Insert new entry */
if (new_ext->ee_len) {
o_start[i] = *new_ext;
ext4_ext_store_pblock(&o_start[i++], ext4_ext_pblock(new_ext));
}
/* Insert end entry */
if (end_ext->ee_len)
o_start[i] = *end_ext;
/* Increment the total entries counter on the extent block */
le16_add_cpu(&eh->eh_entries, range_to_move);
}
/**
* mext_insert_extents - Insert new extent
*
* @handle: journal handle
* @orig_inode: original inode
* @orig_path: path indicates first extent to be changed
* @o_start: first original extent to be changed
* @o_end: last original extent to be changed
* @start_ext: first new extent to be inserted
* @new_ext: middle of new extent to be inserted
* @end_ext: last new extent to be inserted
*
* Call the function to insert extents. If we cannot add more extents into
* the leaf block, we call mext_insert_across_blocks() to create a
* new leaf block. Otherwise call mext_insert_inside_block(). Return 0
* on success, or a negative error value on failure.
*/
static int
mext_insert_extents(handle_t *handle, struct inode *orig_inode,
struct ext4_ext_path *orig_path,
struct ext4_extent *o_start,
struct ext4_extent *o_end,
struct ext4_extent *start_ext,
struct ext4_extent *new_ext,
struct ext4_extent *end_ext)
{
struct ext4_extent_header *eh;
unsigned long need_slots, slots_range;
int range_to_move, depth, ret;
/*
* The extents need to be inserted
* start_extent + new_extent + end_extent.
*/
need_slots = (start_ext->ee_len ? 1 : 0) + (end_ext->ee_len ? 1 : 0) +
(new_ext->ee_len ? 1 : 0);
/* The number of slots between start and end */
slots_range = ((unsigned long)(o_end + 1) - (unsigned long)o_start + 1)
/ sizeof(struct ext4_extent);
/* Range to move the end of extent */
range_to_move = need_slots - slots_range;
depth = orig_path->p_depth;
orig_path += depth;
eh = orig_path->p_hdr;
if (depth) {
/* Register to journal */
ret = ext4_journal_get_write_access(handle, orig_path->p_bh);
if (ret)
return ret;
}
/* Expansion */
if (range_to_move > 0 &&
(range_to_move > le16_to_cpu(eh->eh_max)
- le16_to_cpu(eh->eh_entries))) {
ret = mext_insert_across_blocks(handle, orig_inode, o_start,
o_end, start_ext, new_ext, end_ext);
if (ret < 0)
return ret;
} else
mext_insert_inside_block(o_start, o_end, start_ext, new_ext,
end_ext, eh, range_to_move);
if (depth) {
ret = ext4_handle_dirty_metadata(handle, orig_inode,
orig_path->p_bh);
if (ret)
return ret;
} else {
ret = ext4_mark_inode_dirty(handle, orig_inode);
if (ret < 0)
return ret;
}
return 0;
}
/**
* mext_leaf_block - Move one leaf extent block into the inode.
*
* @handle: journal handle
* @orig_inode: original inode
* @orig_path: path indicates first extent to be changed
* @dext: donor extent
* @from: start offset on the target file
*
* In order to insert extents into the leaf block, we must divide the extent
* in the leaf block into three extents. The one is located to be inserted
* extents, and the others are located around it.
*
* Therefore, this function creates structures to save extents of the leaf
* block, and inserts extents by calling mext_insert_extents() with
* created extents. Return 0 on success, or a negative error value on failure.
*/
static int
mext_leaf_block(handle_t *handle, struct inode *orig_inode,
struct ext4_ext_path *orig_path, struct ext4_extent *dext,
ext4_lblk_t *from)
{
struct ext4_extent *oext, *o_start, *o_end, *prev_ext;
struct ext4_extent new_ext, start_ext, end_ext;
ext4_lblk_t new_ext_end;
int oext_alen, new_ext_alen, end_ext_alen;
int depth = ext_depth(orig_inode);
int ret;
start_ext.ee_block = end_ext.ee_block = 0;
o_start = o_end = oext = orig_path[depth].p_ext;
oext_alen = ext4_ext_get_actual_len(oext);
start_ext.ee_len = end_ext.ee_len = 0;
new_ext.ee_block = cpu_to_le32(*from);
ext4_ext_store_pblock(&new_ext, ext4_ext_pblock(dext));
new_ext.ee_len = dext->ee_len;
new_ext_alen = ext4_ext_get_actual_len(&new_ext);
new_ext_end = le32_to_cpu(new_ext.ee_block) + new_ext_alen - 1;
/*
* Case: original extent is first
* oext |--------|
* new_ext |--|
* start_ext |--|
*/
if (le32_to_cpu(oext->ee_block) < le32_to_cpu(new_ext.ee_block) &&
le32_to_cpu(new_ext.ee_block) <
le32_to_cpu(oext->ee_block) + oext_alen) {
start_ext.ee_len = cpu_to_le16(le32_to_cpu(new_ext.ee_block) -
le32_to_cpu(oext->ee_block));
start_ext.ee_block = oext->ee_block;
copy_extent_status(oext, &start_ext);
} else if (oext > EXT_FIRST_EXTENT(orig_path[depth].p_hdr)) {
prev_ext = oext - 1;
/*
* We can merge new_ext into previous extent,
* if these are contiguous and same extent type.
*/
if (ext4_can_extents_be_merged(orig_inode, prev_ext,
&new_ext)) {
o_start = prev_ext;
start_ext.ee_len = cpu_to_le16(
ext4_ext_get_actual_len(prev_ext) +
new_ext_alen);
start_ext.ee_block = oext->ee_block;
copy_extent_status(prev_ext, &start_ext);
new_ext.ee_len = 0;
}
}
/*
* Case: new_ext_end must be less than oext
* oext |-----------|
* new_ext |-------|
*/
if (le32_to_cpu(oext->ee_block) + oext_alen - 1 < new_ext_end) {
EXT4_ERROR_INODE(orig_inode,
"new_ext_end(%u) should be less than or equal to "
"oext->ee_block(%u) + oext_alen(%d) - 1",
new_ext_end, le32_to_cpu(oext->ee_block),
oext_alen);
ret = -EIO;
goto out;
}
/*
* Case: new_ext is smaller than original extent
* oext |---------------|
* new_ext |-----------|
* end_ext |---|
*/
if (le32_to_cpu(oext->ee_block) <= new_ext_end &&
new_ext_end < le32_to_cpu(oext->ee_block) + oext_alen - 1) {
end_ext.ee_len =
cpu_to_le16(le32_to_cpu(oext->ee_block) +
oext_alen - 1 - new_ext_end);
copy_extent_status(oext, &end_ext);
end_ext_alen = ext4_ext_get_actual_len(&end_ext);
ext4_ext_store_pblock(&end_ext,
(ext4_ext_pblock(o_end) + oext_alen - end_ext_alen));
end_ext.ee_block =
cpu_to_le32(le32_to_cpu(o_end->ee_block) +
oext_alen - end_ext_alen);
}
ret = mext_insert_extents(handle, orig_inode, orig_path, o_start,
o_end, &start_ext, &new_ext, &end_ext);
out:
return ret;
}
/**
* mext_calc_swap_extents - Calculate extents for extent swapping.
*
* @tmp_dext: the extent that will belong to the original inode
* @tmp_oext: the extent that will belong to the donor inode
* @orig_off: block offset of original inode
* @donor_off: block offset of donor inode
* @max_count: the maximum length of extents
*
* Return 0 on success, or a negative error value on failure.
*/
static int
mext_calc_swap_extents(struct ext4_extent *tmp_dext,
struct ext4_extent *tmp_oext,
ext4_lblk_t orig_off, ext4_lblk_t donor_off,
ext4_lblk_t max_count)
{
ext4_lblk_t diff, orig_diff;
struct ext4_extent dext_old, oext_old;
BUG_ON(orig_off != donor_off);
/* original and donor extents have to cover the same block offset */
if (orig_off < le32_to_cpu(tmp_oext->ee_block) ||
le32_to_cpu(tmp_oext->ee_block) +
ext4_ext_get_actual_len(tmp_oext) - 1 < orig_off)
return -ENODATA;
if (orig_off < le32_to_cpu(tmp_dext->ee_block) ||
le32_to_cpu(tmp_dext->ee_block) +
ext4_ext_get_actual_len(tmp_dext) - 1 < orig_off)
return -ENODATA;
dext_old = *tmp_dext;
oext_old = *tmp_oext;
/* When tmp_dext is too large, pick up the target range. */
diff = donor_off - le32_to_cpu(tmp_dext->ee_block);
ext4_ext_store_pblock(tmp_dext, ext4_ext_pblock(tmp_dext) + diff);
tmp_dext->ee_block =
cpu_to_le32(le32_to_cpu(tmp_dext->ee_block) + diff);
tmp_dext->ee_len = cpu_to_le16(le16_to_cpu(tmp_dext->ee_len) - diff);
if (max_count < ext4_ext_get_actual_len(tmp_dext))
tmp_dext->ee_len = cpu_to_le16(max_count);
orig_diff = orig_off - le32_to_cpu(tmp_oext->ee_block);
ext4_ext_store_pblock(tmp_oext, ext4_ext_pblock(tmp_oext) + orig_diff);
/* Adjust extent length if donor extent is larger than orig */
if (ext4_ext_get_actual_len(tmp_dext) >
ext4_ext_get_actual_len(tmp_oext) - orig_diff)
tmp_dext->ee_len = cpu_to_le16(le16_to_cpu(tmp_oext->ee_len) -
orig_diff);
tmp_oext->ee_len = cpu_to_le16(ext4_ext_get_actual_len(tmp_dext));
copy_extent_status(&oext_old, tmp_dext);
copy_extent_status(&dext_old, tmp_oext);
return 0;
}
/**
* mext_replace_branches - Replace original extents with new extents
*
* @handle: journal handle
* @orig_inode: original inode
* @donor_inode: donor inode
* @from: block offset of orig_inode
* @count: block count to be replaced
* @err: pointer to save return value
*
* Replace original inode extents and donor inode extents page by page.
* We implement this replacement in the following three steps:
* 1. Save the block information of original and donor inodes into
* dummy extents.
* 2. Change the block information of original inode to point at the
* donor inode blocks.
* 3. Change the block information of donor inode to point at the saved
* original inode blocks in the dummy extents.
*
* Return replaced block count.
*/
static int
mext_replace_branches(handle_t *handle, struct inode *orig_inode,
struct inode *donor_inode, ext4_lblk_t from,
ext4_lblk_t count, int *err)
{
struct ext4_ext_path *orig_path = NULL;
struct ext4_ext_path *donor_path = NULL;
struct ext4_extent *oext, *dext;
struct ext4_extent tmp_dext, tmp_oext;
ext4_lblk_t orig_off = from, donor_off = from;
int depth;
int replaced_count = 0;
int dext_alen;
/* Protect extent trees against block allocations via delalloc */
double_down_write_data_sem(orig_inode, donor_inode);
/* Get the original extent for the block "orig_off" */
*err = get_ext_path(orig_inode, orig_off, &orig_path);
if (*err)
goto out;
/* Get the donor extent for the head */
*err = get_ext_path(donor_inode, donor_off, &donor_path);
if (*err)
goto out;
depth = ext_depth(orig_inode);
oext = orig_path[depth].p_ext;
tmp_oext = *oext;
depth = ext_depth(donor_inode);
dext = donor_path[depth].p_ext;
tmp_dext = *dext;
*err = mext_calc_swap_extents(&tmp_dext, &tmp_oext, orig_off,
donor_off, count);
if (*err)
goto out;
/* Loop for the donor extents */
while (1) {
/* The extent for donor must be found. */
if (!dext) {
EXT4_ERROR_INODE(donor_inode,
"The extent for donor must be found");
*err = -EIO;
goto out;
} else if (donor_off != le32_to_cpu(tmp_dext.ee_block)) {
EXT4_ERROR_INODE(donor_inode,
"Donor offset(%u) and the first block of donor "
"extent(%u) should be equal",
donor_off,
le32_to_cpu(tmp_dext.ee_block));
*err = -EIO;
goto out;
}
/* Set donor extent to orig extent */
*err = mext_leaf_block(handle, orig_inode,
orig_path, &tmp_dext, &orig_off);
if (*err)
goto out;
/* Set orig extent to donor extent */
*err = mext_leaf_block(handle, donor_inode,
donor_path, &tmp_oext, &donor_off);
if (*err)
goto out;
dext_alen = ext4_ext_get_actual_len(&tmp_dext);
replaced_count += dext_alen;
donor_off += dext_alen;
orig_off += dext_alen;
/* Already moved the expected blocks */
if (replaced_count >= count)
break;
if (orig_path)
ext4_ext_drop_refs(orig_path);
*err = get_ext_path(orig_inode, orig_off, &orig_path);
if (*err)
goto out;
depth = ext_depth(orig_inode);
oext = orig_path[depth].p_ext;
tmp_oext = *oext;
if (donor_path)
ext4_ext_drop_refs(donor_path);
*err = get_ext_path(donor_inode, donor_off, &donor_path);
if (*err)
goto out;
depth = ext_depth(donor_inode);
dext = donor_path[depth].p_ext;
tmp_dext = *dext;
*err = mext_calc_swap_extents(&tmp_dext, &tmp_oext, orig_off,
donor_off, count - replaced_count);
if (*err)
goto out;
}
out:
if (orig_path) {
ext4_ext_drop_refs(orig_path);
kfree(orig_path);
}
if (donor_path) {
ext4_ext_drop_refs(donor_path);
kfree(donor_path);
}
ext4_ext_invalidate_cache(orig_inode);
ext4_ext_invalidate_cache(donor_inode);
double_up_write_data_sem(orig_inode, donor_inode);
return replaced_count;
}
/**
* move_extent_per_page - Move extent data per page
*
* @o_filp: file structure of original file
* @donor_inode: donor inode
* @orig_page_offset: page index on original file
* @data_offset_in_page: block index where data swapping starts
* @block_len_in_page: the number of blocks to be swapped
* @uninit: orig extent is uninitialized or not
* @err: pointer to save return value
*
* Save the data in original inode blocks and replace original inode extents
* with donor inode extents by calling mext_replace_branches().
* Finally, write out the saved data in new original inode blocks. Return
* replaced block count.
*/
static int
move_extent_per_page(struct file *o_filp, struct inode *donor_inode,
pgoff_t orig_page_offset, int data_offset_in_page,
int block_len_in_page, int uninit, int *err)
{
struct inode *orig_inode = o_filp->f_dentry->d_inode;
struct address_space *mapping = orig_inode->i_mapping;
struct buffer_head *bh;
struct page *page = NULL;
const struct address_space_operations *a_ops = mapping->a_ops;
handle_t *handle;
ext4_lblk_t orig_blk_offset;
long long offs = orig_page_offset << PAGE_CACHE_SHIFT;
unsigned long blocksize = orig_inode->i_sb->s_blocksize;
unsigned int w_flags = 0;
unsigned int tmp_data_size, data_size, replaced_size;
void *fsdata;
int i, jblocks;
int err2 = 0;
int replaced_count = 0;
int blocks_per_page = PAGE_CACHE_SIZE >> orig_inode->i_blkbits;
/*
* It needs twice the amount of ordinary journal buffers because
* inode and donor_inode may change each different metadata blocks.
*/
jblocks = ext4_writepage_trans_blocks(orig_inode) * 2;
handle = ext4_journal_start(orig_inode, jblocks);
if (IS_ERR(handle)) {
*err = PTR_ERR(handle);
return 0;
}
if (segment_eq(get_fs(), KERNEL_DS))
w_flags |= AOP_FLAG_UNINTERRUPTIBLE;
orig_blk_offset = orig_page_offset * blocks_per_page +
data_offset_in_page;
/*
* If orig extent is uninitialized one,
* it's not necessary force the page into memory
* and then force it to be written out again.
* Just swap data blocks between orig and donor.
*/
if (uninit) {
replaced_count = mext_replace_branches(handle, orig_inode,
donor_inode, orig_blk_offset,
block_len_in_page, err);
goto out2;
}
offs = (long long)orig_blk_offset << orig_inode->i_blkbits;
/* Calculate data_size */
if ((orig_blk_offset + block_len_in_page - 1) ==
((orig_inode->i_size - 1) >> orig_inode->i_blkbits)) {
/* Replace the last block */
tmp_data_size = orig_inode->i_size & (blocksize - 1);
/*
* If data_size equal zero, it shows data_size is multiples of
* blocksize. So we set appropriate value.
*/
if (tmp_data_size == 0)
tmp_data_size = blocksize;
data_size = tmp_data_size +
((block_len_in_page - 1) << orig_inode->i_blkbits);
} else
data_size = block_len_in_page << orig_inode->i_blkbits;
replaced_size = data_size;
*err = a_ops->write_begin(o_filp, mapping, offs, data_size, w_flags,
&page, &fsdata);
if (unlikely(*err < 0))
goto out;
if (!PageUptodate(page)) {
mapping->a_ops->readpage(o_filp, page);
lock_page(page);
}
/*
* try_to_release_page() doesn't call releasepage in writeback mode.
* We should care about the order of writing to the same file
* by multiple move extent processes.
* It needs to call wait_on_page_writeback() to wait for the
* writeback of the page.
*/
wait_on_page_writeback(page);
/* Release old bh and drop refs */
try_to_release_page(page, 0);
replaced_count = mext_replace_branches(handle, orig_inode, donor_inode,
orig_blk_offset, block_len_in_page,
&err2);
if (err2) {
if (replaced_count) {
block_len_in_page = replaced_count;
replaced_size =
block_len_in_page << orig_inode->i_blkbits;
} else
goto out;
}
if (!page_has_buffers(page))
create_empty_buffers(page, 1 << orig_inode->i_blkbits, 0);
bh = page_buffers(page);
for (i = 0; i < data_offset_in_page; i++)
bh = bh->b_this_page;
for (i = 0; i < block_len_in_page; i++) {
*err = ext4_get_block(orig_inode,
(sector_t)(orig_blk_offset + i), bh, 0);
if (*err < 0)
goto out;
if (bh->b_this_page != NULL)
bh = bh->b_this_page;
}
*err = a_ops->write_end(o_filp, mapping, offs, data_size, replaced_size,
page, fsdata);
page = NULL;
out:
if (unlikely(page)) {
if (PageLocked(page))
unlock_page(page);
page_cache_release(page);
ext4_journal_stop(handle);
}
out2:
ext4_journal_stop(handle);
if (err2)
*err = err2;
return replaced_count;
}
/**
* mext_check_arguments - Check whether move extent can be done
*
* @orig_inode: original inode
* @donor_inode: donor inode
* @orig_start: logical start offset in block for orig
* @donor_start: logical start offset in block for donor
* @len: the number of blocks to be moved
*
* Check the arguments of ext4_move_extents() whether the files can be
* exchanged with each other.
* Return 0 on success, or a negative error value on failure.
*/
static int
mext_check_arguments(struct inode *orig_inode,
struct inode *donor_inode, __u64 orig_start,
__u64 donor_start, __u64 *len)
{
ext4_lblk_t orig_blocks, donor_blocks;
unsigned int blkbits = orig_inode->i_blkbits;
unsigned int blocksize = 1 << blkbits;
if (donor_inode->i_mode & (S_ISUID|S_ISGID)) {
ext4_debug("ext4 move extent: suid or sgid is set"
" to donor file [ino:orig %lu, donor %lu]\n",
orig_inode->i_ino, donor_inode->i_ino);
return -EINVAL;
}
if (IS_IMMUTABLE(donor_inode) || IS_APPEND(donor_inode))
return -EPERM;
/* Ext4 move extent does not support swapfile */
if (IS_SWAPFILE(orig_inode) || IS_SWAPFILE(donor_inode)) {
ext4_debug("ext4 move extent: The argument files should "
"not be swapfile [ino:orig %lu, donor %lu]\n",
orig_inode->i_ino, donor_inode->i_ino);
return -EINVAL;
}
/* Files should be in the same ext4 FS */
if (orig_inode->i_sb != donor_inode->i_sb) {
ext4_debug("ext4 move extent: The argument files "
"should be in same FS [ino:orig %lu, donor %lu]\n",
orig_inode->i_ino, donor_inode->i_ino);
return -EINVAL;
}
/* Ext4 move extent supports only extent based file */
if (!(ext4_test_inode_flag(orig_inode, EXT4_INODE_EXTENTS))) {
ext4_debug("ext4 move extent: orig file is not extents "
"based file [ino:orig %lu]\n", orig_inode->i_ino);
return -EOPNOTSUPP;
} else if (!(ext4_test_inode_flag(donor_inode, EXT4_INODE_EXTENTS))) {
ext4_debug("ext4 move extent: donor file is not extents "
"based file [ino:donor %lu]\n", donor_inode->i_ino);
return -EOPNOTSUPP;
}
if ((!orig_inode->i_size) || (!donor_inode->i_size)) {
ext4_debug("ext4 move extent: File size is 0 byte\n");
return -EINVAL;
}
/* Start offset should be same */
if (orig_start != donor_start) {
ext4_debug("ext4 move extent: orig and donor's start "
"offset are not same [ino:orig %lu, donor %lu]\n",
orig_inode->i_ino, donor_inode->i_ino);
return -EINVAL;
}
if ((orig_start >= EXT_MAX_BLOCKS) ||
(donor_start >= EXT_MAX_BLOCKS) ||
(*len > EXT_MAX_BLOCKS) ||
(orig_start + *len >= EXT_MAX_BLOCKS)) {
ext4_debug("ext4 move extent: Can't handle over [%u] blocks "
"[ino:orig %lu, donor %lu]\n", EXT_MAX_BLOCKS,
orig_inode->i_ino, donor_inode->i_ino);
return -EINVAL;
}
if (orig_inode->i_size > donor_inode->i_size) {
donor_blocks = (donor_inode->i_size + blocksize - 1) >> blkbits;
/* TODO: eliminate this artificial restriction */
if (orig_start >= donor_blocks) {
ext4_debug("ext4 move extent: orig start offset "
"[%llu] should be less than donor file blocks "
"[%u] [ino:orig %lu, donor %lu]\n",
orig_start, donor_blocks,
orig_inode->i_ino, donor_inode->i_ino);
return -EINVAL;
}
/* TODO: eliminate this artificial restriction */
if (orig_start + *len > donor_blocks) {
ext4_debug("ext4 move extent: End offset [%llu] should "
"be less than donor file blocks [%u]."
"So adjust length from %llu to %llu "
"[ino:orig %lu, donor %lu]\n",
orig_start + *len, donor_blocks,
*len, donor_blocks - orig_start,
orig_inode->i_ino, donor_inode->i_ino);
*len = donor_blocks - orig_start;
}
} else {
orig_blocks = (orig_inode->i_size + blocksize - 1) >> blkbits;
if (orig_start >= orig_blocks) {
ext4_debug("ext4 move extent: start offset [%llu] "
"should be less than original file blocks "
"[%u] [ino:orig %lu, donor %lu]\n",
orig_start, orig_blocks,
orig_inode->i_ino, donor_inode->i_ino);
return -EINVAL;
}
if (orig_start + *len > orig_blocks) {
ext4_debug("ext4 move extent: Adjust length "
"from %llu to %llu. Because it should be "
"less than original file blocks "
"[ino:orig %lu, donor %lu]\n",
*len, orig_blocks - orig_start,
orig_inode->i_ino, donor_inode->i_ino);
*len = orig_blocks - orig_start;
}
}
if (!*len) {
ext4_debug("ext4 move extent: len should not be 0 "
"[ino:orig %lu, donor %lu]\n", orig_inode->i_ino,
donor_inode->i_ino);
return -EINVAL;
}
return 0;
}
/**
* mext_inode_double_lock - Lock i_mutex on both @inode1 and @inode2
*
* @inode1: the inode structure
* @inode2: the inode structure
*
* Lock two inodes' i_mutex by i_ino order.
* If inode1 or inode2 is NULL, return -EIO. Otherwise, return 0.
*/
static int
mext_inode_double_lock(struct inode *inode1, struct inode *inode2)
{
int ret = 0;
BUG_ON(inode1 == NULL && inode2 == NULL);
ret = mext_check_null_inode(inode1, inode2, __func__, __LINE__);
if (ret < 0)
goto out;
if (inode1 == inode2) {
mutex_lock(&inode1->i_mutex);
goto out;
}
if (inode1->i_ino < inode2->i_ino) {
mutex_lock_nested(&inode1->i_mutex, I_MUTEX_PARENT);
mutex_lock_nested(&inode2->i_mutex, I_MUTEX_CHILD);
} else {
mutex_lock_nested(&inode2->i_mutex, I_MUTEX_PARENT);
mutex_lock_nested(&inode1->i_mutex, I_MUTEX_CHILD);
}
out:
return ret;
}
/**
* mext_inode_double_unlock - Release i_mutex on both @inode1 and @inode2
*
* @inode1: the inode that is released first
* @inode2: the inode that is released second
*
* If inode1 or inode2 is NULL, return -EIO. Otherwise, return 0.
*/
static int
mext_inode_double_unlock(struct inode *inode1, struct inode *inode2)
{
int ret = 0;
BUG_ON(inode1 == NULL && inode2 == NULL);
ret = mext_check_null_inode(inode1, inode2, __func__, __LINE__);
if (ret < 0)
goto out;
if (inode1)
mutex_unlock(&inode1->i_mutex);
if (inode2 && inode2 != inode1)
mutex_unlock(&inode2->i_mutex);
out:
return ret;
}
/**
* ext4_move_extents - Exchange the specified range of a file
*
* @o_filp: file structure of the original file
* @d_filp: file structure of the donor file
* @orig_start: start offset in block for orig
* @donor_start: start offset in block for donor
* @len: the number of blocks to be moved
* @moved_len: moved block length
*
* This function returns 0 and moved block length is set in moved_len
* if succeed, otherwise returns error value.
*
* Note: ext4_move_extents() proceeds the following order.
* 1:ext4_move_extents() calculates the last block number of moving extent
* function by the start block number (orig_start) and the number of blocks
* to be moved (len) specified as arguments.
* If the {orig, donor}_start points a hole, the extent's start offset
* pointed by ext_cur (current extent), holecheck_path, orig_path are set
* after hole behind.
* 2:Continue step 3 to step 5, until the holecheck_path points to last_extent
* or the ext_cur exceeds the block_end which is last logical block number.
* 3:To get the length of continues area, call mext_next_extent()
* specified with the ext_cur (initial value is holecheck_path) re-cursive,
* until find un-continuous extent, the start logical block number exceeds
* the block_end or the extent points to the last extent.
* 4:Exchange the original inode data with donor inode data
* from orig_page_offset to seq_end_page.
* The start indexes of data are specified as arguments.
* That of the original inode is orig_page_offset,
* and the donor inode is also orig_page_offset
* (To easily handle blocksize != pagesize case, the offset for the
* donor inode is block unit).
* 5:Update holecheck_path and orig_path to points a next proceeding extent,
* then returns to step 2.
* 6:Release holecheck_path, orig_path and set the len to moved_len
* which shows the number of moved blocks.
* The moved_len is useful for the command to calculate the file offset
* for starting next move extent ioctl.
* 7:Return 0 on success, or a negative error value on failure.
*/
int
ext4_move_extents(struct file *o_filp, struct file *d_filp,
__u64 orig_start, __u64 donor_start, __u64 len,
__u64 *moved_len)
{
struct inode *orig_inode = o_filp->f_dentry->d_inode;
struct inode *donor_inode = d_filp->f_dentry->d_inode;
struct ext4_ext_path *orig_path = NULL, *holecheck_path = NULL;
struct ext4_extent *ext_prev, *ext_cur, *ext_dummy;
ext4_lblk_t block_start = orig_start;
ext4_lblk_t block_end, seq_start, add_blocks, file_end, seq_blocks = 0;
ext4_lblk_t rest_blocks;
pgoff_t orig_page_offset = 0, seq_end_page;
int ret1, ret2, depth, last_extent = 0;
int blocks_per_page = PAGE_CACHE_SIZE >> orig_inode->i_blkbits;
int data_offset_in_page;
int block_len_in_page;
int uninit;
/* orig and donor should be different file */
if (orig_inode->i_ino == donor_inode->i_ino) {
ext4_debug("ext4 move extent: The argument files should not "
"be same file [ino:orig %lu, donor %lu]\n",
orig_inode->i_ino, donor_inode->i_ino);
return -EINVAL;
}
/* Regular file check */
if (!S_ISREG(orig_inode->i_mode) || !S_ISREG(donor_inode->i_mode)) {
ext4_debug("ext4 move extent: The argument files should be "
"regular file [ino:orig %lu, donor %lu]\n",
orig_inode->i_ino, donor_inode->i_ino);
return -EINVAL;
}
/* Protect orig and donor inodes against a truncate */
ret1 = mext_inode_double_lock(orig_inode, donor_inode);
if (ret1 < 0)
return ret1;
/* Protect extent tree against block allocations via delalloc */
double_down_write_data_sem(orig_inode, donor_inode);
/* Check the filesystem environment whether move_extent can be done */
ret1 = mext_check_arguments(orig_inode, donor_inode, orig_start,
donor_start, &len);
if (ret1)
goto out;
file_end = (i_size_read(orig_inode) - 1) >> orig_inode->i_blkbits;
block_end = block_start + len - 1;
if (file_end < block_end)
len -= block_end - file_end;
ret1 = get_ext_path(orig_inode, block_start, &orig_path);
if (ret1)
goto out;
/* Get path structure to check the hole */
ret1 = get_ext_path(orig_inode, block_start, &holecheck_path);
if (ret1)
goto out;
depth = ext_depth(orig_inode);
ext_cur = holecheck_path[depth].p_ext;
/*
* Get proper starting location of block replacement if block_start was
* within the hole.
*/
if (le32_to_cpu(ext_cur->ee_block) +
ext4_ext_get_actual_len(ext_cur) - 1 < block_start) {
/*
* The hole exists between extents or the tail of
* original file.
*/
last_extent = mext_next_extent(orig_inode,
holecheck_path, &ext_cur);
if (last_extent < 0) {
ret1 = last_extent;
goto out;
}
last_extent = mext_next_extent(orig_inode, orig_path,
&ext_dummy);
if (last_extent < 0) {
ret1 = last_extent;
goto out;
}
seq_start = le32_to_cpu(ext_cur->ee_block);
} else if (le32_to_cpu(ext_cur->ee_block) > block_start)
/* The hole exists at the beginning of original file. */
seq_start = le32_to_cpu(ext_cur->ee_block);
else
seq_start = block_start;
/* No blocks within the specified range. */
if (le32_to_cpu(ext_cur->ee_block) > block_end) {
ext4_debug("ext4 move extent: The specified range of file "
"may be the hole\n");
ret1 = -EINVAL;
goto out;
}
/* Adjust start blocks */
add_blocks = min(le32_to_cpu(ext_cur->ee_block) +
ext4_ext_get_actual_len(ext_cur), block_end + 1) -
max(le32_to_cpu(ext_cur->ee_block), block_start);
while (!last_extent && le32_to_cpu(ext_cur->ee_block) <= block_end) {
seq_blocks += add_blocks;
/* Adjust tail blocks */
if (seq_start + seq_blocks - 1 > block_end)
seq_blocks = block_end - seq_start + 1;
ext_prev = ext_cur;
last_extent = mext_next_extent(orig_inode, holecheck_path,
&ext_cur);
if (last_extent < 0) {
ret1 = last_extent;
break;
}
add_blocks = ext4_ext_get_actual_len(ext_cur);
/*
* Extend the length of contiguous block (seq_blocks)
* if extents are contiguous.
*/
if (ext4_can_extents_be_merged(orig_inode,
ext_prev, ext_cur) &&
block_end >= le32_to_cpu(ext_cur->ee_block) &&
!last_extent)
continue;
/* Is original extent is uninitialized */
uninit = ext4_ext_is_uninitialized(ext_prev);
data_offset_in_page = seq_start % blocks_per_page;
/*
* Calculate data blocks count that should be swapped
* at the first page.
*/
if (data_offset_in_page + seq_blocks > blocks_per_page) {
/* Swapped blocks are across pages */
block_len_in_page =
blocks_per_page - data_offset_in_page;
} else {
/* Swapped blocks are in a page */
block_len_in_page = seq_blocks;
}
orig_page_offset = seq_start >>
(PAGE_CACHE_SHIFT - orig_inode->i_blkbits);
seq_end_page = (seq_start + seq_blocks - 1) >>
(PAGE_CACHE_SHIFT - orig_inode->i_blkbits);
seq_start = le32_to_cpu(ext_cur->ee_block);
rest_blocks = seq_blocks;
/*
* Up semaphore to avoid following problems:
* a. transaction deadlock among ext4_journal_start,
* ->write_begin via pagefault, and jbd2_journal_commit
* b. racing with ->readpage, ->write_begin, and ext4_get_block
* in move_extent_per_page
*/
double_up_write_data_sem(orig_inode, donor_inode);
while (orig_page_offset <= seq_end_page) {
/* Swap original branches with new branches */
block_len_in_page = move_extent_per_page(
o_filp, donor_inode,
orig_page_offset,
data_offset_in_page,
block_len_in_page, uninit,
&ret1);
/* Count how many blocks we have exchanged */
*moved_len += block_len_in_page;
if (ret1 < 0)
break;
if (*moved_len > len) {
EXT4_ERROR_INODE(orig_inode,
"We replaced blocks too much! "
"sum of replaced: %llu requested: %llu",
*moved_len, len);
ret1 = -EIO;
break;
}
orig_page_offset++;
data_offset_in_page = 0;
rest_blocks -= block_len_in_page;
if (rest_blocks > blocks_per_page)
block_len_in_page = blocks_per_page;
else
block_len_in_page = rest_blocks;
}
double_down_write_data_sem(orig_inode, donor_inode);
if (ret1 < 0)
break;
/* Decrease buffer counter */
if (holecheck_path)
ext4_ext_drop_refs(holecheck_path);
ret1 = get_ext_path(orig_inode, seq_start, &holecheck_path);
if (ret1)
break;
depth = holecheck_path->p_depth;
/* Decrease buffer counter */
if (orig_path)
ext4_ext_drop_refs(orig_path);
ret1 = get_ext_path(orig_inode, seq_start, &orig_path);
if (ret1)
break;
ext_cur = holecheck_path[depth].p_ext;
add_blocks = ext4_ext_get_actual_len(ext_cur);
seq_blocks = 0;
}
out:
if (*moved_len) {
ext4_discard_preallocations(orig_inode);
ext4_discard_preallocations(donor_inode);
}
if (orig_path) {
ext4_ext_drop_refs(orig_path);
kfree(orig_path);
}
if (holecheck_path) {
ext4_ext_drop_refs(holecheck_path);
kfree(holecheck_path);
}
double_up_write_data_sem(orig_inode, donor_inode);
ret2 = mext_inode_double_unlock(orig_inode, donor_inode);
if (ret1)
return ret1;
else if (ret2)
return ret2;
return 0;
}
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