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Btrfs: fix unexpected cow in run_delalloc_nocow

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commit 5811375325 upstream.

Fstests generic/475 provides a way to fail metadata reads while
checking if checksum exists for the inode inside run_delalloc_nocow(),
and csum_exist_in_range() interprets error (-EIO) as inode having
checksum and makes its caller enter the cow path.

In case of free space inode, this ends up with a warning in
cow_file_range().

The same problem applies to btrfs_cross_ref_exist() since it may also
read metadata in between.

With this, run_delalloc_nocow() bails out when errors occur at the two
places.

cc: <stable@vger.kernel.org> v2.6.28+
Fixes: 17d217fe97 ("Btrfs: fix nodatasum handling in balancing code")
Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Liu Bo 2018-01-31 17:09:13 -07:00 committed by Greg Kroah-Hartman
parent 62532640c8
commit 4be89529c0
1 changed files with 32 additions and 5 deletions
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37
fs/btrfs/inode.c
View file

@ -1257,6 +1257,8 @@ static noinline int csum_exist_in_range(struct btrfs_fs_info *fs_info,
list_del(&sums->list);
kfree(sums);
}
if (ret < 0)
return ret;
return 1;
}
@ -1389,10 +1391,23 @@ static noinline int run_delalloc_nocow(struct inode *inode,
goto out_check;
if (btrfs_extent_readonly(fs_info, disk_bytenr))
goto out_check;
if (btrfs_cross_ref_exist(root, ino,
found_key.offset -
extent_offset, disk_bytenr))
ret = btrfs_cross_ref_exist(root, ino,
found_key.offset -
extent_offset, disk_bytenr);
if (ret) {
/*
* ret could be -EIO if the above fails to read
* metadata.
*/
if (ret < 0) {
if (cow_start != (u64)-1)
cur_offset = cow_start;
goto error;
}
WARN_ON_ONCE(nolock);
goto out_check;
}
disk_bytenr += extent_offset;
disk_bytenr += cur_offset - found_key.offset;
num_bytes = min(end + 1, extent_end) - cur_offset;
@ -1410,10 +1425,22 @@ static noinline int run_delalloc_nocow(struct inode *inode,
* this ensure that csum for a given extent are
* either valid or do not exist.
*/
if (csum_exist_in_range(fs_info, disk_bytenr,
num_bytes)) {
ret = csum_exist_in_range(fs_info, disk_bytenr,
num_bytes);
if (ret) {
if (!nolock)
btrfs_end_write_no_snapshotting(root);
/*
* ret could be -EIO if the above fails to read
* metadata.
*/
if (ret < 0) {
if (cow_start != (u64)-1)
cur_offset = cow_start;
goto error;
}
WARN_ON_ONCE(nolock);
goto out_check;
}
if (!btrfs_inc_nocow_writers(fs_info, disk_bytenr)) {