At 11/19/2016 10:52 AM, Jeff Mahoney wrote:
From: Jeff Mahoney <jeffm@xxxxxxxx>
Subject: btrfs: Ensure proper sector alignment for
btrfs_free_reserved_data_space
References: bsc#1005666
Patch-mainline: Submitted 18 Nov 2016, linux-btrfs
This fixes the WARN_ON on BTRFS_I(inode)->reserved_extents in
btrfs_destroy_inode and the WARN_ON on nonzero delalloc bytes on umount
with qgroups enabled.
I was able to reproduce this by setting up a small (~500kb) quota limit
and writing a file one byte at a time until I hit the limit. The warnings
would all hit on umount.
The root cause is that we would reserve a block-sized range in both
the reservation and the quota in btrfs_check_data_free_space, but if we
encountered a problem (like e.g. EDQUOT), we would only release the single
byte in the qgroup reservation.
Good catch.
> That caused an iotree state split, which
increased the number of outstanding extents, in turn disallowing releasing
the metadata reservation.
Signed-off-by: Jeff Mahoney <jeffm@xxxxxxxx>
Reviewed-by: Qu Wenruo <quwenruo@xxxxxxxxxxxxxx>
What about adding more assert/warn_on to reservation/qgroup freeing and
allocation functions?
It would help much more to detect similar problems.
Thanks,
Qu
---
fs/btrfs/extent-tree.c | 7 +++++++
1 file changed, 7 insertions(+)
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -3822,6 +3822,13 @@ void btrfs_free_reserved_data_space_noqu
*/
void btrfs_free_reserved_data_space(struct inode *inode, u64 start, u64 len)
{
+ struct btrfs_root *root = BTRFS_I(inode)->root;
+
+ /* Make sure the range is aligned to sectorsize */
+ len = round_up(start + len, root->sectorsize) -
+ round_down(start, root->sectorsize);
+ start = round_down(start, root->sectorsize);
+
btrfs_free_reserved_data_space_noquota(inode, start, len);
btrfs_qgroup_free_data(inode, start, len);
}
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