diff options
Diffstat (limited to 'fs/btrfs/inode.c')
| -rw-r--r-- | fs/btrfs/inode.c | 25 |
1 files changed, 23 insertions, 2 deletions
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c index 25dcff7..41a5688 100644 --- a/fs/btrfs/inode.c +++ b/fs/btrfs/inode.c @@ -7430,7 +7430,26 @@ static int lock_extent_direct(struct inode *inode, u64 lockstart, u64 lockend, cached_state, GFP_NOFS); if (ordered) { - btrfs_start_ordered_extent(inode, ordered, 1); + /* + * If we are doing a DIO read and the ordered extent we + * found is for a buffered write, we can not wait for it + * to complete and retry, because if we do so we can + * deadlock with concurrent buffered writes on page + * locks. This happens only if our DIO read covers more + * than one extent map, if at this point has already + * created an ordered extent for a previous extent map + * and locked its range in the inode's io tree, and a + * concurrent write against that previous extent map's + * range and this range started (we unlock the ranges + * in the io tree only when the bios complete and + * buffered writes always lock pages before attempting + * to lock range in the io tree). + */ + if (writing || + test_bit(BTRFS_ORDERED_DIRECT, &ordered->flags)) + btrfs_start_ordered_extent(inode, ordered, 1); + else + ret = -ENOTBLK; btrfs_put_ordered_extent(ordered); } else { /* @@ -7447,9 +7466,11 @@ static int lock_extent_direct(struct inode *inode, u64 lockstart, u64 lockend, * that page. */ ret = -ENOTBLK; - break; } + if (ret) + break; + cond_resched(); } |
