ext4: retry failed direct IO allocations

(cherry picked from commit fbbf69456619de5d251cb9f1df609069178c62d5)

On a 256M filesystem, doing this in a loop:

        xfs_io -F -f -d -c 'pwrite 0 64m' test
        rm -f test

eventually leads to ENOSPC.  (the xfs_io command does a
64m direct IO write to the file "test")

As with other block allocation callers, it looks like we need to
potentially retry the allocations on the initial ENOSPC.

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index aac46d0000af022d70ab5c095aa6a3a618c2d910..6c8411bb05139895b728e59fb677db9e5dee19ee 100644 (file)
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -3372,6 +3372,7 @@ static ssize_t ext4_ind_direct_IO(int rw, struct kiocb *iocb,
        ssize_t ret;
        int orphan = 0;
        size_t count = iov_length(iov, nr_segs);
+       int retries = 0;
 
        if (rw == WRITE) {
                loff_t final_size = offset + count;
@@ -3394,9 +3395,12 @@ static ssize_t ext4_ind_direct_IO(int rw, struct kiocb *iocb,
                }
        }
 
+retry:
        ret = blockdev_direct_IO(rw, iocb, inode, inode->i_sb->s_bdev, iov,
                                 offset, nr_segs,
                                 ext4_get_block, NULL);
+       if (ret == -ENOSPC && ext4_should_retry_alloc(inode->i_sb, &retries))
+               goto retry;
 
        if (orphan) {
                int err;