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Btrfs: fix btrfs_ordered_update_i_size to update disk_i_size properly

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btrfs_ordered_update_i_size can be called by truncate and endio, but
only endio takes ordered_extent which contains the completed IO.

while truncating down a file, if there are some in-flight IOs,
btrfs_ordered_update_i_size in endio will set disk_i_size to
@orig_offset that is zero.  If truncating-down fails somehow, we try to
recover in memory isize with this zero'd disk_i_size.

Fix it by only updating disk_i_size with @orig_offset when
btrfs_ordered_update_i_size is not called from endio while truncating
down and waiting for in-flight IOs completing their work before recover
in-memory size.

Besides fixing the above issue, add an assertion for last_size to double
check we truncate down to the desired size.

Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
Liu Bo
2016-12-01 13:01:02 -08:00
committed by David Sterba
parent f85b7379cd
commit 19fd2df5b1
2 changed files with 26 additions and 2 deletions
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14
fs/btrfs/ordered-data.c
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@@ -984,8 +984,18 @@ int btrfs_ordered_update_i_size(struct inode *inode, u64 offset,
}
disk_i_size = BTRFS_I(inode)->disk_i_size;
/* truncate file */
if (disk_i_size > i_size) {
/*
* truncate file.
* If ordered is not NULL, then this is called from endio and
* disk_i_size will be updated by either truncate itself or any
* in-flight IOs which are inside the disk_i_size.
*
* Because btrfs_setsize() may set i_size with disk_i_size if truncate
* fails somehow, we need to make sure we have a precise disk_i_size by
* updating it as usual.
*
*/
if (!ordered && disk_i_size > i_size) {
BTRFS_I(inode)->disk_i_size = orig_offset;
ret = 0;
goto out;