Btrfs: move O_DIRECT space reservation to btrfs_direct_IO

This moves the delalloc space reservation done for O_DIRECT
into btrfs_direct_IO.  This way we don't leak reserved space
if the generic O_DIRECT write code errors out before it
calls into btrfs_direct_IO.

Signed-off-by: Chris Mason <chris.mason@oracle.com>

2 files changed, 8 insertions, 6 deletions

diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index 54556cae4497..79437c5eeb1e 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -888,14 +888,9 @@ static ssize_t btrfs_file_aio_write(struct kiocb *iocb,
         BTRFS_I(inode)->sequence++;
 
         if (unlikely(file->f_flags & O_DIRECT)) {
-                ret = btrfs_delalloc_reserve_space(inode, count);
-                if (ret)
-                        goto out;
-
                 num_written = generic_file_direct_write(iocb, iov, &nr_segs,
                                                         pos, ppos, count,
                                                         ocount);
-
                 /*
                  * the generic O_DIRECT will update in-memory i_size after the
                  * DIOs are done.  But our endio handlers that update the on
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 00aefbdcc2df..ca9d5501d340 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -5602,9 +5602,16 @@ static ssize_t btrfs_direct_IO(int rw, struct kiocb *iocb,
         ssize_t ret;
         int writing = rw & WRITE;
         int write_bits = 0;
+        size_t count = iov_length(iov, nr_segs);
 
         lockstart = offset;
-        lockend = offset + iov_length(iov, nr_segs) - 1;
+        lockend = offset + count - 1;
+
+        if (writing) {
+                ret = btrfs_delalloc_reserve_space(inode, count);
+                if (ret)
+                        goto out;
+        }
 
         while (1) {
                 lock_extent_bits(&BTRFS_I(inode)->io_tree, lockstart, lockend,