Patch "btrfs: Fix quota reservation leak on preallocated files" has been added to the 4.14-stable tree

This is a note to let you know that I've just added the patch titled

btrfs: Fix quota reservation leak on preallocated files

to the 4.14-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
btrfs-fix-quota-reservation-leak-on-preallocated-files.patch
and it can be found in the queue-4.14 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Justin Maggard <[email protected]>
Date: Mon, 30 Oct 2017 15:29:10 -0700
Subject: btrfs: Fix quota reservation leak on preallocated files

From: Justin Maggard <[email protected]>

[ Upstream commit b430b7751286b3acff2d324553c8cec4f1e87764 ]

Commit c6887cd11149 ("Btrfs: don't do nocow check unless we have to") changed the behavior of __btrfs_buffered_write() so that it first tries to get a data space reservation, and then skips the relatively expensive nocow check if the reservation succeeded.

If we have quotas enabled, the data space reservation also includes a quota reservation. But in the rewrite case, the space has already been accounted for in qgroups. So btrfs_check_data_free_space() increases the quota reservation, but it never gets decreased when the data actually gets written and overwrites the pre-existing data. So we're left with both the qgroup and qgroup reservation accounting for the same space.

This commit adds the missing btrfs_qgroup_free_data() call in the case of BTRFS_ORDERED_PREALLOC extents.

---
 fs/btrfs/inode.c |    2 ++
 1 file changed, 2 insertions(+)

@@ -3016,6 +3016,8 @@ static int btrfs_finish_ordered_io(struc
 		compress_type = ordered_extent->compress_type;
 	if (test_bit(BTRFS_ORDERED_PREALLOC, &ordered_extent->flags)) {
 		BUG_ON(compress_type);
+		btrfs_qgroup_free_data(inode, NULL, ordered_extent->file_offset,
+				       ordered_extent->len);
 		ret = btrfs_mark_extent_written(trans, BTRFS_I(inode),
 						ordered_extent->file_offset,
 						ordered_extent->file_offset +

Patches currently in stable-queue which might be from [email protected] are

queue-4.14/btrfs-fix-quota-reservation-leak-on-preallocated-files.patch