ext3: retry failed direct IO allocations

On a 256M 4k block filesystem, doing this in a loop:

    dd if=/dev/zero of=test oflag=direct bs=1M count=64
    rm -f test

eventually leads to spurious ENOSPC:

    dd: writing `test': No space left on device

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

A similar patch went into ext4 (commit
fbbf69456619de5d251cb9f1df609069178c62d5)

Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: Jan Kara <jack@suse.cz>

diff --git a/fs/ext3/inode.c b/fs/ext3/inode.c
index acf1b14..069a163 100644 (file)
--- a/fs/ext3/inode.c
+++ b/fs/ext3/inode.c
@@ -1735,6 +1735,7 @@ static ssize_t ext3_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;
@@ -1757,9 +1758,12 @@ static ssize_t ext3_direct_IO(int rw, struct kiocb *iocb,
                }
        }
 
+retry:
        ret = blockdev_direct_IO(rw, iocb, inode, inode->i_sb->s_bdev, iov,
                                 offset, nr_segs,
                                 ext3_get_block, NULL);
+       if (ret == -ENOSPC && ext3_should_retry_alloc(inode->i_sb, &retries))
+               goto retry;
 
        if (orphan) {
                int err;