Btrfs: account for the correct number of extents for delalloc reservations

Direct IO can easily pass in an buffer that is greater than
BTRFS_MAX_EXTENT_SIZE, so take this into account when reserving extents in the
delalloc reservation code.  Thanks,

Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>

1 files changed, 5 insertions, 1 deletions

diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 92146a5afdc1..96c613bfe157 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -5110,7 +5110,11 @@ int btrfs_delalloc_reserve_metadata(struct inode *inode, u64 num_bytes)
         num_bytes = ALIGN(num_bytes, root->sectorsize);
 
         spin_lock(&BTRFS_I(inode)->lock);
-        BTRFS_I(inode)->outstanding_extents++;
+        nr_extents = (unsigned)div64_u64(num_bytes +
+                                         BTRFS_MAX_EXTENT_SIZE - 1,
+                                         BTRFS_MAX_EXTENT_SIZE);
+        BTRFS_I(inode)->outstanding_extents += nr_extents;
+        nr_extents = 0;
 
         if (BTRFS_I(inode)->outstanding_extents >
             BTRFS_I(inode)->reserved_extents)