* [PATCH] btrfs: Fix quota reservation leak on preallocated files
@ 2017-10-30 22:29 Justin Maggard
2017-10-30 23:39 ` Qu Wenruo
0 siblings, 1 reply; 2+ messages in thread
From: Justin Maggard @ 2017-10-30 22:29 UTC (permalink / raw)
To: linux-btrfs; +Cc: Justin Maggard
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.
Signed-off-by: Justin Maggard <jmaggard@netgear.com>
---
fs/btrfs/inode.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index d94e3f68b9b1..d7881ccf5310 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -3006,6 +3006,8 @@ static int btrfs_finish_ordered_io(struct btrfs_ordered_extent *ordered_extent)
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 +
--
2.14.2
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] btrfs: Fix quota reservation leak on preallocated files
2017-10-30 22:29 [PATCH] btrfs: Fix quota reservation leak on preallocated files Justin Maggard
@ 2017-10-30 23:39 ` Qu Wenruo
0 siblings, 0 replies; 2+ messages in thread
From: Qu Wenruo @ 2017-10-30 23:39 UTC (permalink / raw)
To: Justin Maggard, linux-btrfs; +Cc: Justin Maggard
[-- Attachment #1.1: Type: text/plain, Size: 1735 bytes --]
On 2017年10月31日 06:29, Justin Maggard wrote:
> 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.
>
> Signed-off-by: Justin Maggard <jmaggard@netgear.com>
Reviewed-by: Qu Wenruo <wqu@suse.com>
Thanks,
Qu
> ---
> fs/btrfs/inode.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
> index d94e3f68b9b1..d7881ccf5310 100644
> --- a/fs/btrfs/inode.c
> +++ b/fs/btrfs/inode.c
> @@ -3006,6 +3006,8 @@ static int btrfs_finish_ordered_io(struct btrfs_ordered_extent *ordered_extent)
> 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 +
>
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2017-10-30 23:39 ` Qu Wenruo
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