hello,
Any comments about this patchset?
The first two patches almost don't do any functional change which I think
could be review firstly.
btrfs: improve inode's outstanding_extents computation
btrfs: introduce type based delalloc metadata reserve
Regards,
Xiaoguang Wang
On 11/11/2016 04:39 PM, Wang Xiaoguang wrote:
When having compression enabled, Stefan Priebe ofen got enospc errors
though fs still has much free space. Qu Wenruo also has submitted a
fstests test case which can reproduce this bug steadily, please see
url: https://patchwork.kernel.org/patch/9420527
First patch[1/3] "btrfs: improve inode's outstanding_extents computation" is to
fix outstanding_extents and reserved_extents account issues. This issue was
revealed
by modifying BTRFS_MAX_EXTENT_SIZE(128MB) to 64KB, When modifying
BTRFS_MAX_EXTENT_SIZE(128MB) to 64KB, fsstress test often gets these warnings
from
btrfs_destroy_inode():
WARN_ON(BTRFS_I(inode)->outstanding_extents);
WARN_ON(BTRFS_I(inode)->reserved_extents);
Please see this patch's commit message for detailed info, and this patch is
necessary to patch2 and patch3.
For false enospc, the root reasson is that for compression, its max extent size
will
be 128k, not 128MB. If we still use 128MB as max extent size to reserve
metadata for
compression, obviously it's not appropriate. In patch "btrfs: Introduce COMPRESS
reserve type to fix false enospc for compression" commit message,
we explain why false enospc error occurs, please see it for detailed info.
To fix this issue, we introduce a new enum type:
enum btrfs_metadata_reserve_type {
BTRFS_RESERVE_NORMAL,
BTRFS_RESERVE_COMPRESS,
};
For btrfs_delalloc_[reserve|release]_metadata() and
btrfs_delalloc_[reserve|release]_space(), we introce a new
btrfs_metadata_reserve_type
argument, then if a path needs to go compression, we pass
BTRFS_RESERVE_COMPRESS,
otherwise pass BTRFS_RESERVE_NORMAL.
With these patchs, Stefan no longer saw such false enospc errors, and Qu
Wenruo's
fstests test case will also pass. I have also run whole fstests multiple times,
no regression occurs, thanks.
Wang Xiaoguang (3):
btrfs: improve inode's outstanding_extents computation
btrfs: introduce type based delalloc metadata reserve
btrfs: Introduce COMPRESS reserve type to fix false enospc for
compression
fs/btrfs/ctree.h | 36 +++++--
fs/btrfs/extent-tree.c | 52 ++++++---
fs/btrfs/extent_io.c | 61 ++++++++++-
fs/btrfs/extent_io.h | 5 +
fs/btrfs/file.c | 25 +++--
fs/btrfs/free-space-cache.c | 6 +-
fs/btrfs/inode-map.c | 6 +-
fs/btrfs/inode.c | 246 ++++++++++++++++++++++++++++++++++---------
fs/btrfs/ioctl.c | 16 +--
fs/btrfs/relocation.c | 14 ++-
fs/btrfs/tests/inode-tests.c | 15 +--
11 files changed, 381 insertions(+), 101 deletions(-)
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