Jeff Layton <jlayton@xxxxxxxxxx> writes:
> There's no reason we need to lock the inode for write in order to handle
> an llseek. I suspect this should have been dropped in 2013 when we
> stopped doing vmtruncate in llseek.
>
> With that gone, ceph_llseek is functionally equivalent to
> generic_file_llseek, so just call that after getting the size.
>
> Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx>
> ---
> fs/ceph/file.c | 52 +++++---------------------------------------------
> 1 file changed, 5 insertions(+), 47 deletions(-)
>
Nice! I started reviewing your previous patch, and while checking other
filesystems I wondered if the generic_* could be used instead. And here
it is. And it may even fix races in the SEEK_CUR by locking f_lock.
Reviewed-by: Luís Henriques <lhenriques@xxxxxxx>
Cheers,
--
Luís
> diff --git a/fs/ceph/file.c b/fs/ceph/file.c
> index 0c13a3f23c99..0e82a1c383ca 100644
> --- a/fs/ceph/file.c
> +++ b/fs/ceph/file.c
> @@ -1989,57 +1989,15 @@ static ssize_t ceph_write_iter(struct kiocb *iocb, struct iov_iter *from)
> */
> static loff_t ceph_llseek(struct file *file, loff_t offset, int whence)
> {
> - struct inode *inode = file->f_mapping->host;
> - struct ceph_fs_client *fsc = ceph_inode_to_client(inode);
> - loff_t i_size;
> - loff_t ret;
> -
> - inode_lock(inode);
> -
> if (whence == SEEK_END || whence == SEEK_DATA || whence == SEEK_HOLE) {
> + struct inode *inode = file_inode(file);
> + int ret;
> +
> ret = ceph_do_getattr(inode, CEPH_STAT_CAP_SIZE, false);
> if (ret < 0)
> - goto out;
> - }
> -
> - i_size = i_size_read(inode);
> - switch (whence) {
> - case SEEK_END:
> - offset += i_size;
> - break;
> - case SEEK_CUR:
> - /*
> - * Here we special-case the lseek(fd, 0, SEEK_CUR)
> - * position-querying operation. Avoid rewriting the "same"
> - * f_pos value back to the file because a concurrent read(),
> - * write() or lseek() might have altered it
> - */
> - if (offset == 0) {
> - ret = file->f_pos;
> - goto out;
> - }
> - offset += file->f_pos;
> - break;
> - case SEEK_DATA:
> - if (offset < 0 || offset >= i_size) {
> - ret = -ENXIO;
> - goto out;
> - }
> - break;
> - case SEEK_HOLE:
> - if (offset < 0 || offset >= i_size) {
> - ret = -ENXIO;
> - goto out;
> - }
> - offset = i_size;
> - break;
> + return ret;
> }
> -
> - ret = vfs_setpos(file, offset, max(i_size, fsc->max_file_size));
> -
> -out:
> - inode_unlock(inode);
> - return ret;
> + return generic_file_llseek(file, offset, whence);
> }
>
> static inline void ceph_zero_partial_page(
> --
>
> 2.36.1
>
