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| author | Nikolay Borisov <nborisov@suse.com> | 2018-04-05 10:40:15 +0300 |
|---|---|---|
| committer | David Sterba <dsterba@suse.com> | 2018-04-05 19:22:35 +0200 |
| commit | 1e1c50a929bc9e49bc3f9935b92450d9e69f8158 (patch) | |
| tree | 1e950e1030b25534acc205832c6eae3b05aee1b4 | |
| parent | b98def7ca6e152ee55e36863dddf6f41f12d1dc6 (diff) | |
| download | linux-1e1c50a929bc9e49bc3f9935b92450d9e69f8158.tar.gz linux-1e1c50a929bc9e49bc3f9935b92450d9e69f8158.tar.bz2 linux-1e1c50a929bc9e49bc3f9935b92450d9e69f8158.zip | |
btrfs: Fix possible softlock on single core machines
do_chunk_alloc implements a loop checking whether there is a pending
chunk allocation and if so causes the caller do loop. Generally this
loop is executed only once, however testing with btrfs/072 on a single
core vm machines uncovered an extreme case where the system could loop
indefinitely. This is due to a missing cond_resched when loop which
doesn't give a chance to the previous chunk allocator finish its job.
The fix is to simply add the missing cond_resched.
Fixes: 6d74119f1a3e ("Btrfs: avoid taking the chunk_mutex in do_chunk_alloc")
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
| -rw-r--r-- | fs/btrfs/extent-tree.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c index f30548d7e0d2..2caf9958f3e1 100644 --- a/fs/btrfs/extent-tree.c +++ b/fs/btrfs/extent-tree.c @@ -4643,6 +4643,7 @@ again: if (wait_for_alloc) { mutex_unlock(&fs_info->chunk_mutex); wait_for_alloc = 0; + cond_resched(); goto again; } |