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author | Miao Xie <miaox@cn.fujitsu.com> | 2013-02-21 02:48:22 -0700 |
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committer | Chris Mason <chris.mason@fusionio.com> | 2013-02-21 08:11:43 -0500 |
commit | 172a50497ffaf84d60dff37fbeb03894268fe5c2 (patch) | |
tree | 7aae1c2d33bba4ef727d89e573a02cc90c7fcfc4 /fs/btrfs/super.c | |
parent | 38c227d87c49ad5d173cb5d4374d49acec6a495d (diff) | |
download | linux-172a50497ffaf84d60dff37fbeb03894268fe5c2.tar.bz2 |
Btrfs: fix wrong outstanding_extents when doing DIO write
When running the 083th case of xfstests on the filesystem with
"compress-force=lzo", the following WARNINGs were triggered.
WARNING: at fs/btrfs/inode.c:7908
WARNING: at fs/btrfs/inode.c:7909
WARNING: at fs/btrfs/inode.c:7911
WARNING: at fs/btrfs/extent-tree.c:4510
WARNING: at fs/btrfs/extent-tree.c:4511
This problem was introduced by the patch "Btrfs: fix deadlock due
to unsubmitted". In this patch, there are two bugs which caused
the above problem.
The 1st one is a off-by-one bug, if the DIO write return 0, it is
also a short write, we need release the reserved space for it. But
we didn't do it in that patch. Fix it by change "ret > 0" to
"ret >= 0".
The 2nd one is ->outstanding_extents was increased twice when
a short write happened. As we know, ->outstanding_extents is
a counter to keep track of the number of extent items we may
use duo to delalloc, when we reserve the free space for a
delalloc write, we assume that the write will introduce just
one extent item, so we increase ->outstanding_extents by 1 at
that time. And then we will increase it every time we split the
write, it is done at the beginning of btrfs_get_blocks_direct().
So when a short write happens, we needn't increase
->outstanding_extents again. But this patch done.
In order to fix the 2nd problem, I re-write the logic for
->outstanding_extents operation. We don't increase it at the
beginning of btrfs_get_blocks_direct(), instead, we just
increase it when the split actually happens.
Reported-by: Mitch Harder <mitch.harder@sabayonlinux.org>
Signed-off-by: Miao Xie <miaox@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@fusionio.com>
Diffstat (limited to 'fs/btrfs/super.c')
0 files changed, 0 insertions, 0 deletions