scsi: target: core: add missing file_{start,end}_write()

The callers of vfs_iter_write() are required to hold file_start_write().
file_start_write() is a no-op for the S_ISBLK() case, but it is really
needed when the backing file is a regular file.

We are going to move file_{start,end}_write() into vfs_iter_write(), but
we need to fix this first, so that the fix could be backported to stable
kernels.

Suggested-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/ZV8ETIpM+wZa33B5@infradead.org/
Cc:  <stable@vger.kernel.org>
Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Link: https://lore.kernel.org/r/20231123092000.2665902-1-amir73il@gmail.com
Acked-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Christian Brauner <brauner@kernel.org>

diff --git a/drivers/target/target_core_file.c b/drivers/target/target_core_file.c
index 4d447520bab87d6133ba2611f37c4955e641fe5c..4e4cf6c34a775c4483c4b16ad7bf6e78ef72f220 100644 (file)
--- a/drivers/target/target_core_file.c
+++ b/drivers/target/target_core_file.c
@@ -332,11 +332,13 @@ static int fd_do_rw(struct se_cmd *cmd, struct file *fd,
        }
 
        iov_iter_bvec(&iter, is_write, bvec, sgl_nents, len);
-       if (is_write)
+       if (is_write) {
+               file_start_write(fd);
                ret = vfs_iter_write(fd, &iter, &pos, 0);
-       else
+               file_end_write(fd);
+       } else {
                ret = vfs_iter_read(fd, &iter, &pos, 0);
-
+       }
        if (is_write) {
                if (ret < 0 || ret != data_length) {
                        pr_err("%s() write returned %d\n", __func__, ret);
@@ -467,7 +469,9 @@ fd_execute_write_same(struct se_cmd *cmd)
        }
 
        iov_iter_bvec(&iter, ITER_SOURCE, bvec, nolb, len);
+       file_start_write(fd_dev->fd_file);
        ret = vfs_iter_write(fd_dev->fd_file, &iter, &pos, 0);
+       file_end_write(fd_dev->fd_file);
 
        kfree(bvec);
        if (ret < 0 || ret != len) {