Gitweb: http://git.kernel.org/linus/ab6e24103cbd215e922938a4f58c75194761a60e
Commit: ab6e24103cbd215e922938a4f58c75194761a60e
Parent: 109f6aef5fc436f355ad027f4d97bd696df2049a
Author: Josef Bacik <josef@redhat.com>
AuthorDate: Fri Mar 19 14:38:13 2010 +0000
Committer: Chris Mason <chris.mason@oracle.com>
CommitDate: Mon Apr 5 16:04:50 2010 -0400
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>
---
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 101041d..786899d 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.
--
To unsubscribe from this list: send the line "unsubscribe git-commits-head" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
