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| author | Josef Bacik <josef@redhat.com> | 2010-03-19 14:38:13 +0000 |
|---|---|---|
| committer | Chris Mason <chris.mason@oracle.com> | 2010-04-05 16:04:50 -0400 |
| commit | ab6e24103cbd215e922938a4f58c75194761a60e (patch) | |
| tree | d54479feddd7fe625888dd62084621d4d0871c4b /fs/btrfs | |
| parent | 109f6aef5fc436f355ad027f4d97bd696df2049a (diff) | |
| download | linux-3.10-ab6e24103cbd215e922938a4f58c75194761a60e.tar.gz linux-3.10-ab6e24103cbd215e922938a4f58c75194761a60e.tar.bz2 linux-3.10-ab6e24103cbd215e922938a4f58c75194761a60e.zip | |
Btrfs: fix data enospc check overflow
Because we account for reserved space we get from the allocator before we
actually account for allocating delalloc space, we can have a small window where
the amount of "used" space in a space_info is more than the total amount of
space in the space_info. This will cause a overflow in our check, so it will
seem like we have _tons_ of free space, and we'll allow reservations to occur
that will end up larger than the amount of space we have. I've seen users
report ENOSPC panic's in cow_file_range a few times recently, so I tried to
reproduce this problem and found I could reproduce it if I ran one of my tests
in a loop for like 20 minutes. With this patch my test ran all night without
issues. Thanks,
Signed-off-by: Josef Bacik <josef@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
Diffstat (limited to 'fs/btrfs')
| -rw-r--r-- | fs/btrfs/extent-tree.c | 20 |
1 files changed, 15 insertions, 5 deletions
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c index 101041d4d2b..786899da3eb 100644 --- a/fs/btrfs/extent-tree.c +++ b/fs/btrfs/extent-tree.c @@ -3234,7 +3234,8 @@ int btrfs_check_data_free_space(struct btrfs_root *root, struct inode *inode, u64 bytes) { struct btrfs_space_info *data_sinfo; - int ret = 0, committed = 0; + u64 used; + int ret = 0, committed = 0, flushed = 0; /* make sure bytes are sectorsize aligned */ bytes = (bytes + root->sectorsize - 1) & ~((u64)root->sectorsize - 1); @@ -3246,12 +3247,21 @@ int btrfs_check_data_free_space(struct btrfs_root *root, struct inode *inode, again: /* make sure we have enough space to handle the data first */ spin_lock(&data_sinfo->lock); - if (data_sinfo->total_bytes - data_sinfo->bytes_used - - data_sinfo->bytes_delalloc - data_sinfo->bytes_reserved - - data_sinfo->bytes_pinned - data_sinfo->bytes_readonly - - data_sinfo->bytes_may_use - data_sinfo->bytes_super < bytes) { + used = data_sinfo->bytes_used + data_sinfo->bytes_delalloc + + data_sinfo->bytes_reserved + data_sinfo->bytes_pinned + + data_sinfo->bytes_readonly + data_sinfo->bytes_may_use + + data_sinfo->bytes_super; + + if (used + bytes > data_sinfo->total_bytes) { struct btrfs_trans_handle *trans; + if (!flushed) { + spin_unlock(&data_sinfo->lock); + flush_delalloc(root, data_sinfo); + flushed = 1; + goto again; + } + /* * if we don't have enough free bytes in this space then we need * to alloc a new chunk. |