diff options
| author | Josef Bacik <josef@toxicpanda.com> | 2017-10-19 21:16:01 +0300 |
|---|---|---|
| committer | David Sterba <dsterba@suse.com> | 2017-11-01 22:45:35 +0300 |
| commit | ce8ea7cc6eb3139f4c730d647325e69354159b0f (patch) | |
| tree | 22c6c34e55ce1dabf8ca7d5d81205828f387ea51 /fs/btrfs | |
| parent | 0e0adbcfdc908684317c99a9bf5e13383f03b7ec (diff) | |
| download | linux-ce8ea7cc6eb3139f4c730d647325e69354159b0f.tar.xz | |
btrfs: don't call btrfs_start_delalloc_roots in flushoncommit
We're holding the sb_start_intwrite lock at this point, and doing async
filemap_flush of the inodes will result in a deadlock if we freeze the
fs during this operation. This is because we could do a
btrfs_join_transaction() in the thread we are waiting on which would
block at sb_start_intwrite, and thus deadlock. Using
writeback_inodes_sb() side steps the problem by not introducing all of
these extra locking dependencies.
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Diffstat (limited to 'fs/btrfs')
| -rw-r--r-- | fs/btrfs/transaction.c | 11 |
1 files changed, 10 insertions, 1 deletions
diff --git a/fs/btrfs/transaction.c b/fs/btrfs/transaction.c index 68c3e1c04bca..5a8c2649af2f 100644 --- a/fs/btrfs/transaction.c +++ b/fs/btrfs/transaction.c @@ -1916,8 +1916,17 @@ static void cleanup_transaction(struct btrfs_trans_handle *trans, static inline int btrfs_start_delalloc_flush(struct btrfs_fs_info *fs_info) { + /* + * We use writeback_inodes_sb here because if we used + * btrfs_start_delalloc_roots we would deadlock with fs freeze. + * Currently are holding the fs freeze lock, if we do an async flush + * we'll do btrfs_join_transaction() and deadlock because we need to + * wait for the fs freeze lock. Using the direct flushing we benefit + * from already being in a transaction and our join_transaction doesn't + * have to re-take the fs freeze lock. + */ if (btrfs_test_opt(fs_info, FLUSHONCOMMIT)) - return btrfs_start_delalloc_roots(fs_info, 1, -1); + writeback_inodes_sb(fs_info->sb, WB_REASON_SYNC); return 0; } |