linux/fs/ext4/move_extent.c

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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 cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h percpu.h is included by sched.h and module.h and thus ends up being included when building most .c files. percpu.h includes slab.h which in turn includes gfp.h making everything defined by the two files universally available and complicating inclusion dependencies. percpu.h -> slab.h dependency is about to be removed. Prepare for this change by updating users of gfp and slab facilities include those headers directly instead of assuming availability. As this conversion needs to touch large number of source files, the following script is used as the basis of conversion. http://userweb.kernel.org/~tj/misc/slabh-sweep.py The script does the followings. * Scan files for gfp and slab usages and update includes such that only the necessary includes are there. ie. if only gfp is used, gfp.h, if slab is used, slab.h. * When the script inserts a new include, it looks at the include blocks and try to put the new include such that its order conforms to its surrounding. It's put in the include block which contains core kernel includes, in the same order that the rest are ordered - alphabetical, Christmas tree, rev-Xmas-tree or at the end if there doesn't seem to be any matching order. * If the script can't find a place to put a new include (mostly because the file doesn't have fitting include block), it prints out an error message indicating which .h file needs to be added to the file. The conversion was done in the following steps. 1. The initial automatic conversion of all .c files updated slightly over 4000 files, deleting around 700 includes and adding ~480 gfp.h and ~3000 slab.h inclusions. The script emitted errors for ~400 files. 2. Each error was manually checked. Some didn't need the inclusion, some needed manual addition while adding it to implementation .h or embedding .c file was more appropriate for others. This step added inclusions to around 150 files. 3. The script was run again and the output was compared to the edits from #2 to make sure no file was left behind. 4. Several build tests were done and a couple of problems were fixed. e.g. lib/decompress_*.c used malloc/free() wrappers around slab APIs requiring slab.h to be added manually. 5. The script was run on all .h files but without automatically editing them as sprinkling gfp.h and slab.h inclusions around .h files could easily lead to inclusion dependency hell. Most gfp.h inclusion directives were ignored as stuff from gfp.h was usually wildly available and often used in preprocessor macros. Each slab.h inclusion directive was examined and added manually as necessary. 6. percpu.h was updated not to include slab.h. 7. Build test were done on the following configurations and failures were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my distributed build env didn't work with gcov compiles) and a few more options had to be turned off depending on archs to make things build (like ipr on powerpc/64 which failed due to missing writeq). * x86 and x86_64 UP and SMP allmodconfig and a custom test config. * powerpc and powerpc64 SMP allmodconfig * sparc and sparc64 SMP allmodconfig * ia64 SMP allmodconfig * s390 SMP allmodconfig * alpha SMP allmodconfig * um on x86_64 SMP allmodconfig 8. percpu.h modifications were reverted so that it could be applied as a separate patch and serve as bisection point. Given the fact that I had only a couple of failures from tests on step 6, I'm fairly confident about the coverage of this conversion patch. If there is a breakage, it's likely to be something in one of the arch headers which should be easily discoverable easily on most builds of the specific arch. Signed-off-by: Tejun Heo <tj@kernel.org> Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2010-03-24 08:04:11 +00:00
#include <linux/slab.h>
#include "ext4_jbd2.h"
#include "ext4.h"
#include "ext4_extents.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 **orig_path)
{
int ret = 0;
struct ext4_ext_path *path;
path = ext4_ext_find_extent(inode, lblock, *orig_path);
if (IS_ERR(path))
ret = PTR_ERR(path);
else if (path[ext_depth(inode)].p_ext == NULL)
ret = -ENODATA;
else
*orig_path = path;
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;
}
/**
* double_down_write_data_sem - Acquire two inodes' write lock of i_data_sem
*
* Acquire write lock of i_data_sem of the two inodes
*/
static void
double_down_write_data_sem(struct inode *first, struct inode *second)
{
if (first < second) {
down_write(&EXT4_I(first)->i_data_sem);
down_write_nested(&EXT4_I(second)->i_data_sem, SINGLE_DEPTH_NESTING);
} else {
down_write(&EXT4_I(second)->i_data_sem);
down_write_nested(&EXT4_I(first)->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);
le32_add_cpu(&tmp_dext->ee_block, diff);
le16_add_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_check_coverage - Check that all extents in range has the same type
*
* @inode: inode in question
* @from: block offset of inode
* @count: block count to be checked
* @uninit: extents expected to be uninitialized
* @err: pointer to save error value
*
* Return 1 if all extents in range has expected type, and zero otherwise.
*/
static int
mext_check_coverage(struct inode *inode, ext4_lblk_t from, ext4_lblk_t count,
int uninit, int *err)
{
struct ext4_ext_path *path = NULL;
struct ext4_extent *ext;
int ret = 0;
ext4_lblk_t last = from + count;
while (from < last) {
*err = get_ext_path(inode, from, &path);
if (*err)
goto out;
ext = path[ext_depth(inode)].p_ext;
if (uninit != ext4_ext_is_uninitialized(ext))
goto out;
from += ext4_ext_get_actual_len(ext);
ext4_ext_drop_refs(path);
}
ret = 1;
out:
if (path) {
ext4_ext_drop_refs(path);
kfree(path);
}
return ret;
}
/**
* 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;
*err = ext4_es_remove_extent(orig_inode, from, count);
if (*err)
goto out;
*err = ext4_es_remove_extent(donor_inode, from, count);
if (*err)
goto out;
/* 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;
if (unlikely(!dext))
goto missing_donor_extent;
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 (unlikely(!dext)) {
missing_donor_extent:
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);
}
return replaced_count;
}
ext4: clean up online defrag bugs in move_extent_per_page() Non-full list of bugs: 1) uninitialized extent optimization does not hold page's lock, and simply replace brunches after that writeback code goes crazy because block mapping changed under it's feets kernel BUG at fs/ext4/inode.c:1434! ( 288'th xfstress) 2) uninitialized extent may became initialized right after we drop i_data_sem, so extent state must be rechecked 3) Locked pages goes uptodate via following sequence: ->readpage(page); lock_page(page); use_that_page(page) But after readpage() one may invalidate it because it is uptodate and unlocked (reclaimer does that) As result kernel bug at include/linux/buffer_head.c:133! 4) We call write_begin() with already opened stansaction which result in following deadlock: ->move_extent_per_page() ->ext4_journal_start()-> hold journal transaction ->write_begin() ->ext4_da_write_begin() ->ext4_nonda_switch() ->writeback_inodes_sb_if_idle() --> will wait for journal_stop() 5) try_to_release_page() may fail and it does fail if one of page's bh was pinned by journal 6) If we about to change page's mapping we MUST hold it's lock during entire remapping procedure, this is true for both pages(original and donor one) Fixes: - Avoid (1) and (2) simply by temproraly drop uninitialized extent handling optimization, this will be reimplemented later. - Fix (3) by manually forcing page to uptodate state w/o dropping it's lock - Fix (4) by rearranging existing locking: from: journal_start(); ->write_begin to: write_begin(); journal_extend() - Fix (5) simply by checking retvalue - Fix (6) by locking both (original and donor one) pages during extent swap with help of mext_page_double_lock() Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2012-09-26 16:52:07 +00:00
/**
* mext_page_double_lock - Grab and lock pages on both @inode1 and @inode2
*
* @inode1: the inode structure
* @inode2: the inode structure
* @index: page index
* @page: result page vector
*
* Grab two locked pages for inode's by inode order
*/
static int
mext_page_double_lock(struct inode *inode1, struct inode *inode2,
pgoff_t index, struct page *page[2])
{
struct address_space *mapping[2];
unsigned fl = AOP_FLAG_NOFS;
BUG_ON(!inode1 || !inode2);
if (inode1 < inode2) {
mapping[0] = inode1->i_mapping;
mapping[1] = inode2->i_mapping;
} else {
mapping[0] = inode2->i_mapping;
mapping[1] = inode1->i_mapping;
}
page[0] = grab_cache_page_write_begin(mapping[0], index, fl);
if (!page[0])
return -ENOMEM;
page[1] = grab_cache_page_write_begin(mapping[1], index, fl);
if (!page[1]) {
unlock_page(page[0]);
page_cache_release(page[0]);
return -ENOMEM;
}
if (inode1 > inode2) {
struct page *tmp;
tmp = page[0];
page[0] = page[1];
page[1] = tmp;
}
return 0;
}
/* Force page buffers uptodate w/o dropping page's lock */
static int
mext_page_mkuptodate(struct page *page, unsigned from, unsigned to)
{
struct inode *inode = page->mapping->host;
sector_t block;
struct buffer_head *bh, *head, *arr[MAX_BUF_PER_PAGE];
unsigned int blocksize, block_start, block_end;
int i, err, nr = 0, partial = 0;
BUG_ON(!PageLocked(page));
BUG_ON(PageWriteback(page));
if (PageUptodate(page))
return 0;
blocksize = 1 << inode->i_blkbits;
if (!page_has_buffers(page))
create_empty_buffers(page, blocksize, 0);
head = page_buffers(page);
block = (sector_t)page->index << (PAGE_CACHE_SHIFT - inode->i_blkbits);
for (bh = head, block_start = 0; bh != head || !block_start;
block++, block_start = block_end, bh = bh->b_this_page) {
block_end = block_start + blocksize;
if (block_end <= from || block_start >= to) {
if (!buffer_uptodate(bh))
partial = 1;
continue;
}
if (buffer_uptodate(bh))
continue;
if (!buffer_mapped(bh)) {
int err = 0;
err = ext4_get_block(inode, block, bh, 0);
if (err) {
SetPageError(page);
return err;
}
if (!buffer_mapped(bh)) {
zero_user(page, block_start, blocksize);
if (!err)
set_buffer_uptodate(bh);
continue;
}
}
BUG_ON(nr >= MAX_BUF_PER_PAGE);
arr[nr++] = bh;
}
/* No io required */
if (!nr)
goto out;
for (i = 0; i < nr; i++) {
bh = arr[i];
if (!bh_uptodate_or_lock(bh)) {
err = bh_submit_read(bh);
if (err)
return err;
}
}
out:
if (!partial)
SetPageUptodate(page);
return 0;
}
/**
* 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 = file_inode(o_filp);
ext4: clean up online defrag bugs in move_extent_per_page() Non-full list of bugs: 1) uninitialized extent optimization does not hold page's lock, and simply replace brunches after that writeback code goes crazy because block mapping changed under it's feets kernel BUG at fs/ext4/inode.c:1434! ( 288'th xfstress) 2) uninitialized extent may became initialized right after we drop i_data_sem, so extent state must be rechecked 3) Locked pages goes uptodate via following sequence: ->readpage(page); lock_page(page); use_that_page(page) But after readpage() one may invalidate it because it is uptodate and unlocked (reclaimer does that) As result kernel bug at include/linux/buffer_head.c:133! 4) We call write_begin() with already opened stansaction which result in following deadlock: ->move_extent_per_page() ->ext4_journal_start()-> hold journal transaction ->write_begin() ->ext4_da_write_begin() ->ext4_nonda_switch() ->writeback_inodes_sb_if_idle() --> will wait for journal_stop() 5) try_to_release_page() may fail and it does fail if one of page's bh was pinned by journal 6) If we about to change page's mapping we MUST hold it's lock during entire remapping procedure, this is true for both pages(original and donor one) Fixes: - Avoid (1) and (2) simply by temproraly drop uninitialized extent handling optimization, this will be reimplemented later. - Fix (3) by manually forcing page to uptodate state w/o dropping it's lock - Fix (4) by rearranging existing locking: from: journal_start(); ->write_begin to: write_begin(); journal_extend() - Fix (5) simply by checking retvalue - Fix (6) by locking both (original and donor one) pages during extent swap with help of mext_page_double_lock() Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2012-09-26 16:52:07 +00:00
struct page *pagep[2] = {NULL, NULL};
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;
ext4: clean up online defrag bugs in move_extent_per_page() Non-full list of bugs: 1) uninitialized extent optimization does not hold page's lock, and simply replace brunches after that writeback code goes crazy because block mapping changed under it's feets kernel BUG at fs/ext4/inode.c:1434! ( 288'th xfstress) 2) uninitialized extent may became initialized right after we drop i_data_sem, so extent state must be rechecked 3) Locked pages goes uptodate via following sequence: ->readpage(page); lock_page(page); use_that_page(page) But after readpage() one may invalidate it because it is uptodate and unlocked (reclaimer does that) As result kernel bug at include/linux/buffer_head.c:133! 4) We call write_begin() with already opened stansaction which result in following deadlock: ->move_extent_per_page() ->ext4_journal_start()-> hold journal transaction ->write_begin() ->ext4_da_write_begin() ->ext4_nonda_switch() ->writeback_inodes_sb_if_idle() --> will wait for journal_stop() 5) try_to_release_page() may fail and it does fail if one of page's bh was pinned by journal 6) If we about to change page's mapping we MUST hold it's lock during entire remapping procedure, this is true for both pages(original and donor one) Fixes: - Avoid (1) and (2) simply by temproraly drop uninitialized extent handling optimization, this will be reimplemented later. - Fix (3) by manually forcing page to uptodate state w/o dropping it's lock - Fix (4) by rearranging existing locking: from: journal_start(); ->write_begin to: write_begin(); journal_extend() - Fix (5) simply by checking retvalue - Fix (6) by locking both (original and donor one) pages during extent swap with help of mext_page_double_lock() Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2012-09-26 16:52:07 +00:00
int err2, jblocks, retries = 0;
int replaced_count = 0;
ext4: clean up online defrag bugs in move_extent_per_page() Non-full list of bugs: 1) uninitialized extent optimization does not hold page's lock, and simply replace brunches after that writeback code goes crazy because block mapping changed under it's feets kernel BUG at fs/ext4/inode.c:1434! ( 288'th xfstress) 2) uninitialized extent may became initialized right after we drop i_data_sem, so extent state must be rechecked 3) Locked pages goes uptodate via following sequence: ->readpage(page); lock_page(page); use_that_page(page) But after readpage() one may invalidate it because it is uptodate and unlocked (reclaimer does that) As result kernel bug at include/linux/buffer_head.c:133! 4) We call write_begin() with already opened stansaction which result in following deadlock: ->move_extent_per_page() ->ext4_journal_start()-> hold journal transaction ->write_begin() ->ext4_da_write_begin() ->ext4_nonda_switch() ->writeback_inodes_sb_if_idle() --> will wait for journal_stop() 5) try_to_release_page() may fail and it does fail if one of page's bh was pinned by journal 6) If we about to change page's mapping we MUST hold it's lock during entire remapping procedure, this is true for both pages(original and donor one) Fixes: - Avoid (1) and (2) simply by temproraly drop uninitialized extent handling optimization, this will be reimplemented later. - Fix (3) by manually forcing page to uptodate state w/o dropping it's lock - Fix (4) by rearranging existing locking: from: journal_start(); ->write_begin to: write_begin(); journal_extend() - Fix (5) simply by checking retvalue - Fix (6) by locking both (original and donor one) pages during extent swap with help of mext_page_double_lock() Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2012-09-26 16:52:07 +00:00
int from = data_offset_in_page << orig_inode->i_blkbits;
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.
*/
ext4: clean up online defrag bugs in move_extent_per_page() Non-full list of bugs: 1) uninitialized extent optimization does not hold page's lock, and simply replace brunches after that writeback code goes crazy because block mapping changed under it's feets kernel BUG at fs/ext4/inode.c:1434! ( 288'th xfstress) 2) uninitialized extent may became initialized right after we drop i_data_sem, so extent state must be rechecked 3) Locked pages goes uptodate via following sequence: ->readpage(page); lock_page(page); use_that_page(page) But after readpage() one may invalidate it because it is uptodate and unlocked (reclaimer does that) As result kernel bug at include/linux/buffer_head.c:133! 4) We call write_begin() with already opened stansaction which result in following deadlock: ->move_extent_per_page() ->ext4_journal_start()-> hold journal transaction ->write_begin() ->ext4_da_write_begin() ->ext4_nonda_switch() ->writeback_inodes_sb_if_idle() --> will wait for journal_stop() 5) try_to_release_page() may fail and it does fail if one of page's bh was pinned by journal 6) If we about to change page's mapping we MUST hold it's lock during entire remapping procedure, this is true for both pages(original and donor one) Fixes: - Avoid (1) and (2) simply by temproraly drop uninitialized extent handling optimization, this will be reimplemented later. - Fix (3) by manually forcing page to uptodate state w/o dropping it's lock - Fix (4) by rearranging existing locking: from: journal_start(); ->write_begin to: write_begin(); journal_extend() - Fix (5) simply by checking retvalue - Fix (6) by locking both (original and donor one) pages during extent swap with help of mext_page_double_lock() Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2012-09-26 16:52:07 +00:00
again:
*err = 0;
jblocks = ext4_writepage_trans_blocks(orig_inode) * 2;
handle = ext4_journal_start(orig_inode, EXT4_HT_MOVE_EXTENTS, 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;
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;
ext4: clean up online defrag bugs in move_extent_per_page() Non-full list of bugs: 1) uninitialized extent optimization does not hold page's lock, and simply replace brunches after that writeback code goes crazy because block mapping changed under it's feets kernel BUG at fs/ext4/inode.c:1434! ( 288'th xfstress) 2) uninitialized extent may became initialized right after we drop i_data_sem, so extent state must be rechecked 3) Locked pages goes uptodate via following sequence: ->readpage(page); lock_page(page); use_that_page(page) But after readpage() one may invalidate it because it is uptodate and unlocked (reclaimer does that) As result kernel bug at include/linux/buffer_head.c:133! 4) We call write_begin() with already opened stansaction which result in following deadlock: ->move_extent_per_page() ->ext4_journal_start()-> hold journal transaction ->write_begin() ->ext4_da_write_begin() ->ext4_nonda_switch() ->writeback_inodes_sb_if_idle() --> will wait for journal_stop() 5) try_to_release_page() may fail and it does fail if one of page's bh was pinned by journal 6) If we about to change page's mapping we MUST hold it's lock during entire remapping procedure, this is true for both pages(original and donor one) Fixes: - Avoid (1) and (2) simply by temproraly drop uninitialized extent handling optimization, this will be reimplemented later. - Fix (3) by manually forcing page to uptodate state w/o dropping it's lock - Fix (4) by rearranging existing locking: from: journal_start(); ->write_begin to: write_begin(); journal_extend() - Fix (5) simply by checking retvalue - Fix (6) by locking both (original and donor one) pages during extent swap with help of mext_page_double_lock() Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2012-09-26 16:52:07 +00:00
*err = mext_page_double_lock(orig_inode, donor_inode, orig_page_offset,
pagep);
if (unlikely(*err < 0))
ext4: clean up online defrag bugs in move_extent_per_page() Non-full list of bugs: 1) uninitialized extent optimization does not hold page's lock, and simply replace brunches after that writeback code goes crazy because block mapping changed under it's feets kernel BUG at fs/ext4/inode.c:1434! ( 288'th xfstress) 2) uninitialized extent may became initialized right after we drop i_data_sem, so extent state must be rechecked 3) Locked pages goes uptodate via following sequence: ->readpage(page); lock_page(page); use_that_page(page) But after readpage() one may invalidate it because it is uptodate and unlocked (reclaimer does that) As result kernel bug at include/linux/buffer_head.c:133! 4) We call write_begin() with already opened stansaction which result in following deadlock: ->move_extent_per_page() ->ext4_journal_start()-> hold journal transaction ->write_begin() ->ext4_da_write_begin() ->ext4_nonda_switch() ->writeback_inodes_sb_if_idle() --> will wait for journal_stop() 5) try_to_release_page() may fail and it does fail if one of page's bh was pinned by journal 6) If we about to change page's mapping we MUST hold it's lock during entire remapping procedure, this is true for both pages(original and donor one) Fixes: - Avoid (1) and (2) simply by temproraly drop uninitialized extent handling optimization, this will be reimplemented later. - Fix (3) by manually forcing page to uptodate state w/o dropping it's lock - Fix (4) by rearranging existing locking: from: journal_start(); ->write_begin to: write_begin(); journal_extend() - Fix (5) simply by checking retvalue - Fix (6) by locking both (original and donor one) pages during extent swap with help of mext_page_double_lock() Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2012-09-26 16:52:07 +00:00
goto stop_journal;
/*
* If orig extent was uninitialized it can become initialized
* at any time after i_data_sem was dropped, in order to
* serialize with delalloc we have recheck extent while we
* hold page's lock, if it is still the case data copy is not
* necessary, just swap data blocks between orig and donor.
*/
if (uninit) {
double_down_write_data_sem(orig_inode, donor_inode);
/* If any of extents in range became initialized we have to
* fallback to data copying */
uninit = mext_check_coverage(orig_inode, orig_blk_offset,
block_len_in_page, 1, err);
if (*err)
goto drop_data_sem;
uninit &= mext_check_coverage(donor_inode, orig_blk_offset,
block_len_in_page, 1, err);
if (*err)
goto drop_data_sem;
if (!uninit) {
double_up_write_data_sem(orig_inode, donor_inode);
goto data_copy;
}
if ((page_has_private(pagep[0]) &&
!try_to_release_page(pagep[0], 0)) ||
(page_has_private(pagep[1]) &&
!try_to_release_page(pagep[1], 0))) {
*err = -EBUSY;
goto drop_data_sem;
}
replaced_count = mext_replace_branches(handle, orig_inode,
donor_inode, orig_blk_offset,
block_len_in_page, err);
drop_data_sem:
double_up_write_data_sem(orig_inode, donor_inode);
goto unlock_pages;
}
data_copy:
ext4: clean up online defrag bugs in move_extent_per_page() Non-full list of bugs: 1) uninitialized extent optimization does not hold page's lock, and simply replace brunches after that writeback code goes crazy because block mapping changed under it's feets kernel BUG at fs/ext4/inode.c:1434! ( 288'th xfstress) 2) uninitialized extent may became initialized right after we drop i_data_sem, so extent state must be rechecked 3) Locked pages goes uptodate via following sequence: ->readpage(page); lock_page(page); use_that_page(page) But after readpage() one may invalidate it because it is uptodate and unlocked (reclaimer does that) As result kernel bug at include/linux/buffer_head.c:133! 4) We call write_begin() with already opened stansaction which result in following deadlock: ->move_extent_per_page() ->ext4_journal_start()-> hold journal transaction ->write_begin() ->ext4_da_write_begin() ->ext4_nonda_switch() ->writeback_inodes_sb_if_idle() --> will wait for journal_stop() 5) try_to_release_page() may fail and it does fail if one of page's bh was pinned by journal 6) If we about to change page's mapping we MUST hold it's lock during entire remapping procedure, this is true for both pages(original and donor one) Fixes: - Avoid (1) and (2) simply by temproraly drop uninitialized extent handling optimization, this will be reimplemented later. - Fix (3) by manually forcing page to uptodate state w/o dropping it's lock - Fix (4) by rearranging existing locking: from: journal_start(); ->write_begin to: write_begin(); journal_extend() - Fix (5) simply by checking retvalue - Fix (6) by locking both (original and donor one) pages during extent swap with help of mext_page_double_lock() Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2012-09-26 16:52:07 +00:00
*err = mext_page_mkuptodate(pagep[0], from, from + replaced_size);
if (*err)
goto unlock_pages;
/* At this point all buffers in range are uptodate, old mapping layout
* is no longer required, try to drop it now. */
if ((page_has_private(pagep[0]) && !try_to_release_page(pagep[0], 0)) ||
(page_has_private(pagep[1]) && !try_to_release_page(pagep[1], 0))) {
*err = -EBUSY;
goto unlock_pages;
}
replaced_count = mext_replace_branches(handle, orig_inode, donor_inode,
ext4: clean up online defrag bugs in move_extent_per_page() Non-full list of bugs: 1) uninitialized extent optimization does not hold page's lock, and simply replace brunches after that writeback code goes crazy because block mapping changed under it's feets kernel BUG at fs/ext4/inode.c:1434! ( 288'th xfstress) 2) uninitialized extent may became initialized right after we drop i_data_sem, so extent state must be rechecked 3) Locked pages goes uptodate via following sequence: ->readpage(page); lock_page(page); use_that_page(page) But after readpage() one may invalidate it because it is uptodate and unlocked (reclaimer does that) As result kernel bug at include/linux/buffer_head.c:133! 4) We call write_begin() with already opened stansaction which result in following deadlock: ->move_extent_per_page() ->ext4_journal_start()-> hold journal transaction ->write_begin() ->ext4_da_write_begin() ->ext4_nonda_switch() ->writeback_inodes_sb_if_idle() --> will wait for journal_stop() 5) try_to_release_page() may fail and it does fail if one of page's bh was pinned by journal 6) If we about to change page's mapping we MUST hold it's lock during entire remapping procedure, this is true for both pages(original and donor one) Fixes: - Avoid (1) and (2) simply by temproraly drop uninitialized extent handling optimization, this will be reimplemented later. - Fix (3) by manually forcing page to uptodate state w/o dropping it's lock - Fix (4) by rearranging existing locking: from: journal_start(); ->write_begin to: write_begin(); journal_extend() - Fix (5) simply by checking retvalue - Fix (6) by locking both (original and donor one) pages during extent swap with help of mext_page_double_lock() Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2012-09-26 16:52:07 +00:00
orig_blk_offset,
block_len_in_page, err);
if (*err) {
if (replaced_count) {
block_len_in_page = replaced_count;
replaced_size =
block_len_in_page << orig_inode->i_blkbits;
} else
ext4: clean up online defrag bugs in move_extent_per_page() Non-full list of bugs: 1) uninitialized extent optimization does not hold page's lock, and simply replace brunches after that writeback code goes crazy because block mapping changed under it's feets kernel BUG at fs/ext4/inode.c:1434! ( 288'th xfstress) 2) uninitialized extent may became initialized right after we drop i_data_sem, so extent state must be rechecked 3) Locked pages goes uptodate via following sequence: ->readpage(page); lock_page(page); use_that_page(page) But after readpage() one may invalidate it because it is uptodate and unlocked (reclaimer does that) As result kernel bug at include/linux/buffer_head.c:133! 4) We call write_begin() with already opened stansaction which result in following deadlock: ->move_extent_per_page() ->ext4_journal_start()-> hold journal transaction ->write_begin() ->ext4_da_write_begin() ->ext4_nonda_switch() ->writeback_inodes_sb_if_idle() --> will wait for journal_stop() 5) try_to_release_page() may fail and it does fail if one of page's bh was pinned by journal 6) If we about to change page's mapping we MUST hold it's lock during entire remapping procedure, this is true for both pages(original and donor one) Fixes: - Avoid (1) and (2) simply by temproraly drop uninitialized extent handling optimization, this will be reimplemented later. - Fix (3) by manually forcing page to uptodate state w/o dropping it's lock - Fix (4) by rearranging existing locking: from: journal_start(); ->write_begin to: write_begin(); journal_extend() - Fix (5) simply by checking retvalue - Fix (6) by locking both (original and donor one) pages during extent swap with help of mext_page_double_lock() Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2012-09-26 16:52:07 +00:00
goto unlock_pages;
}
ext4: clean up online defrag bugs in move_extent_per_page() Non-full list of bugs: 1) uninitialized extent optimization does not hold page's lock, and simply replace brunches after that writeback code goes crazy because block mapping changed under it's feets kernel BUG at fs/ext4/inode.c:1434! ( 288'th xfstress) 2) uninitialized extent may became initialized right after we drop i_data_sem, so extent state must be rechecked 3) Locked pages goes uptodate via following sequence: ->readpage(page); lock_page(page); use_that_page(page) But after readpage() one may invalidate it because it is uptodate and unlocked (reclaimer does that) As result kernel bug at include/linux/buffer_head.c:133! 4) We call write_begin() with already opened stansaction which result in following deadlock: ->move_extent_per_page() ->ext4_journal_start()-> hold journal transaction ->write_begin() ->ext4_da_write_begin() ->ext4_nonda_switch() ->writeback_inodes_sb_if_idle() --> will wait for journal_stop() 5) try_to_release_page() may fail and it does fail if one of page's bh was pinned by journal 6) If we about to change page's mapping we MUST hold it's lock during entire remapping procedure, this is true for both pages(original and donor one) Fixes: - Avoid (1) and (2) simply by temproraly drop uninitialized extent handling optimization, this will be reimplemented later. - Fix (3) by manually forcing page to uptodate state w/o dropping it's lock - Fix (4) by rearranging existing locking: from: journal_start(); ->write_begin to: write_begin(); journal_extend() - Fix (5) simply by checking retvalue - Fix (6) by locking both (original and donor one) pages during extent swap with help of mext_page_double_lock() Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2012-09-26 16:52:07 +00:00
/* Perform all necessary steps similar write_begin()/write_end()
* but keeping in mind that i_size will not change */
*err = __block_write_begin(pagep[0], from, from + replaced_size,
ext4_get_block);
if (!*err)
*err = block_commit_write(pagep[0], from, from + replaced_size);
ext4: clean up online defrag bugs in move_extent_per_page() Non-full list of bugs: 1) uninitialized extent optimization does not hold page's lock, and simply replace brunches after that writeback code goes crazy because block mapping changed under it's feets kernel BUG at fs/ext4/inode.c:1434! ( 288'th xfstress) 2) uninitialized extent may became initialized right after we drop i_data_sem, so extent state must be rechecked 3) Locked pages goes uptodate via following sequence: ->readpage(page); lock_page(page); use_that_page(page) But after readpage() one may invalidate it because it is uptodate and unlocked (reclaimer does that) As result kernel bug at include/linux/buffer_head.c:133! 4) We call write_begin() with already opened stansaction which result in following deadlock: ->move_extent_per_page() ->ext4_journal_start()-> hold journal transaction ->write_begin() ->ext4_da_write_begin() ->ext4_nonda_switch() ->writeback_inodes_sb_if_idle() --> will wait for journal_stop() 5) try_to_release_page() may fail and it does fail if one of page's bh was pinned by journal 6) If we about to change page's mapping we MUST hold it's lock during entire remapping procedure, this is true for both pages(original and donor one) Fixes: - Avoid (1) and (2) simply by temproraly drop uninitialized extent handling optimization, this will be reimplemented later. - Fix (3) by manually forcing page to uptodate state w/o dropping it's lock - Fix (4) by rearranging existing locking: from: journal_start(); ->write_begin to: write_begin(); journal_extend() - Fix (5) simply by checking retvalue - Fix (6) by locking both (original and donor one) pages during extent swap with help of mext_page_double_lock() Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2012-09-26 16:52:07 +00:00
if (unlikely(*err < 0))
goto repair_branches;
/* Even in case of data=writeback it is reasonable to pin
* inode to transaction, to prevent unexpected data loss */
*err = ext4_jbd2_file_inode(handle, orig_inode);
unlock_pages:
unlock_page(pagep[0]);
page_cache_release(pagep[0]);
unlock_page(pagep[1]);
page_cache_release(pagep[1]);
stop_journal:
ext4_journal_stop(handle);
ext4: clean up online defrag bugs in move_extent_per_page() Non-full list of bugs: 1) uninitialized extent optimization does not hold page's lock, and simply replace brunches after that writeback code goes crazy because block mapping changed under it's feets kernel BUG at fs/ext4/inode.c:1434! ( 288'th xfstress) 2) uninitialized extent may became initialized right after we drop i_data_sem, so extent state must be rechecked 3) Locked pages goes uptodate via following sequence: ->readpage(page); lock_page(page); use_that_page(page) But after readpage() one may invalidate it because it is uptodate and unlocked (reclaimer does that) As result kernel bug at include/linux/buffer_head.c:133! 4) We call write_begin() with already opened stansaction which result in following deadlock: ->move_extent_per_page() ->ext4_journal_start()-> hold journal transaction ->write_begin() ->ext4_da_write_begin() ->ext4_nonda_switch() ->writeback_inodes_sb_if_idle() --> will wait for journal_stop() 5) try_to_release_page() may fail and it does fail if one of page's bh was pinned by journal 6) If we about to change page's mapping we MUST hold it's lock during entire remapping procedure, this is true for both pages(original and donor one) Fixes: - Avoid (1) and (2) simply by temproraly drop uninitialized extent handling optimization, this will be reimplemented later. - Fix (3) by manually forcing page to uptodate state w/o dropping it's lock - Fix (4) by rearranging existing locking: from: journal_start(); ->write_begin to: write_begin(); journal_extend() - Fix (5) simply by checking retvalue - Fix (6) by locking both (original and donor one) pages during extent swap with help of mext_page_double_lock() Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2012-09-26 16:52:07 +00:00
/* Buffer was busy because probably is pinned to journal transaction,
* force transaction commit may help to free it. */
if (*err == -EBUSY && ext4_should_retry_alloc(orig_inode->i_sb,
&retries))
goto again;
return replaced_count;
ext4: clean up online defrag bugs in move_extent_per_page() Non-full list of bugs: 1) uninitialized extent optimization does not hold page's lock, and simply replace brunches after that writeback code goes crazy because block mapping changed under it's feets kernel BUG at fs/ext4/inode.c:1434! ( 288'th xfstress) 2) uninitialized extent may became initialized right after we drop i_data_sem, so extent state must be rechecked 3) Locked pages goes uptodate via following sequence: ->readpage(page); lock_page(page); use_that_page(page) But after readpage() one may invalidate it because it is uptodate and unlocked (reclaimer does that) As result kernel bug at include/linux/buffer_head.c:133! 4) We call write_begin() with already opened stansaction which result in following deadlock: ->move_extent_per_page() ->ext4_journal_start()-> hold journal transaction ->write_begin() ->ext4_da_write_begin() ->ext4_nonda_switch() ->writeback_inodes_sb_if_idle() --> will wait for journal_stop() 5) try_to_release_page() may fail and it does fail if one of page's bh was pinned by journal 6) If we about to change page's mapping we MUST hold it's lock during entire remapping procedure, this is true for both pages(original and donor one) Fixes: - Avoid (1) and (2) simply by temproraly drop uninitialized extent handling optimization, this will be reimplemented later. - Fix (3) by manually forcing page to uptodate state w/o dropping it's lock - Fix (4) by rearranging existing locking: from: journal_start(); ->write_begin to: write_begin(); journal_extend() - Fix (5) simply by checking retvalue - Fix (6) by locking both (original and donor one) pages during extent swap with help of mext_page_double_lock() Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2012-09-26 16:52:07 +00:00
repair_branches:
/*
* This should never ever happen!
* Extents are swapped already, but we are not able to copy data.
* Try to swap extents to it's original places
*/
double_down_write_data_sem(orig_inode, donor_inode);
replaced_count = mext_replace_branches(handle, donor_inode, orig_inode,
orig_blk_offset,
block_len_in_page, &err2);
double_up_write_data_sem(orig_inode, donor_inode);
if (replaced_count != block_len_in_page) {
EXT4_ERROR_INODE_BLOCK(orig_inode, (sector_t)(orig_blk_offset),
"Unable to copy data block,"
" data will be lost.");
*err = -EIO;
}
replaced_count = 0;
goto unlock_pages;
}
/**
* 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;
}
/* 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;
}
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 04:05:17 +00:00
if ((orig_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 "
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 04:05:17 +00:00
"[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
*/
static void
mext_inode_double_lock(struct inode *inode1, struct inode *inode2)
{
BUG_ON(inode1 == inode2);
if (inode1 < inode2) {
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);
}
}
/**
* 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
*
*/
static void
mext_inode_double_unlock(struct inode *inode1, struct inode *inode2)
{
mutex_unlock(&inode1->i_mutex);
mutex_unlock(&inode2->i_mutex);
}
/**
* 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 = file_inode(o_filp);
struct inode *donor_inode = file_inode(d_filp);
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 ret, 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;
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;
}
/* orig and donor should be different inodes */
if (orig_inode == donor_inode) {
ext4_debug("ext4 move extent: The argument files should not "
"be same inode [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;
}
/* TODO: This is non obvious task to swap blocks for inodes with full
jornaling enabled */
if (ext4_should_journal_data(orig_inode) ||
ext4_should_journal_data(donor_inode)) {
return -EINVAL;
}
/* Protect orig and donor inodes against a truncate */
mext_inode_double_lock(orig_inode, donor_inode);
/* Wait for all existing dio workers */
ext4_inode_block_unlocked_dio(orig_inode);
ext4_inode_block_unlocked_dio(donor_inode);
inode_dio_wait(orig_inode);
inode_dio_wait(donor_inode);
/* 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 */
ret = mext_check_arguments(orig_inode, donor_inode, orig_start,
donor_start, &len);
if (ret)
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;
ret = get_ext_path(orig_inode, block_start, &orig_path);
if (ret)
goto out;
/* Get path structure to check the hole */
ret = get_ext_path(orig_inode, block_start, &holecheck_path);
if (ret)
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) {
ret = last_extent;
goto out;
}
last_extent = mext_next_extent(orig_inode, orig_path,
&ext_dummy);
if (last_extent < 0) {
ret = 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");
ret = -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) {
ret = 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,
&ret);
/* Count how many blocks we have exchanged */
*moved_len += block_len_in_page;
if (ret < 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);
ret = -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 (ret < 0)
break;
/* Decrease buffer counter */
if (holecheck_path)
ext4_ext_drop_refs(holecheck_path);
ret = get_ext_path(orig_inode, seq_start, &holecheck_path);
if (ret)
break;
depth = holecheck_path->p_depth;
/* Decrease buffer counter */
if (orig_path)
ext4_ext_drop_refs(orig_path);
ret = get_ext_path(orig_inode, seq_start, &orig_path);
if (ret)
break;
ext_cur = holecheck_path[depth].p_ext;
add_blocks = ext4_ext_get_actual_len(ext_cur);
seq_blocks = 0;
}
out:
ext4: Fix double-free of blocks with EXT4_IOC_MOVE_EXT At the beginning of ext4_move_extent(), we call ext4_discard_preallocations() to discard inode PAs of orig and donor inodes. But in the following case, blocks can be double freed, so move ext4_discard_preallocations() to the end of ext4_move_extents(). 1. Discard inode PAs of orig and donor inodes with ext4_discard_preallocations() in ext4_move_extents(). orig : [ DATA1 ] donor: [ DATA2 ] 2. While data blocks are exchanging between orig and donor inodes, new inode PAs is created to orig by other process's block allocation. (Since there are semaphore gaps in ext4_move_extents().) And new inode PAs is used partially (2-1). 2-1 Create new inode PAs to orig inode orig : [ DATA1 | used PA1 | free PA1 ] donor: [ DATA2 ] 3. Donor inode which has old orig inode's blocks is deleted after EXT4_IOC_MOVE_EXT finished (3-1, 3-2). So the block bitmap corresponds to old orig inode's blocks are freed. 3-1 After EXT4_IOC_MOVE_EXT finished orig : [ DATA2 | free PA1 ] donor: [ DATA1 | used PA1 ] 3-2 Delete donor inode orig : [ DATA2 | free PA1 ] donor: [ FREE SPACE(DATA1) | FREE SPACE(used PA1) ] 4. The double-free of blocks is occurred, when close() is called to orig inode. Because ext4_discard_preallocations() for orig inode frees used PA1 and free PA1, though used PA1 is already freed in 3. 4-1 Double-free of blocks is occurred orig : [ DATA2 | FREE SPACE(free PA1) ] donor: [ FREE SPACE(DATA1) | DOUBLE FREE(used PA1) ] Signed-off-by: Akira Fujita <a-fujita@rs.jp.nec.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2009-11-24 15:19:57 +00:00
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);
ext4_inode_resume_unlocked_dio(orig_inode);
ext4_inode_resume_unlocked_dio(donor_inode);
mext_inode_double_unlock(orig_inode, donor_inode);
return ret;
}