On 02/27/2014 03:07 AM, Yan, Zheng wrote:
> Comparing offset with inode->i_sb->s_maxbytes doesn't make sense for
> directory. For a fragmented directory, offset (frag_t, off) can be
> larger than inode->i_sb->s_maxbytes.
>
> At the very beginning of ceph_dir_llseek(), local variable old_offset
> is initialized to parameter offset. This doesn't make sense neither.
> Old_offset should be ceph_make_fpos(fi->frag, fi->next_offset).
This looks OK to me, but I'm not as well-versed in the file system
code as I am in libceph and rbd. It looks like previously this
would produce problems if you ever did an llseek on a directory
that ended up in any fragment but the first.
I have one question/suggestion below, but otherwise:
Reviewed-by: Alex Elder <elder@xxxxxxxxxx>
>
> Signed-off-by: Yan, Zheng <zheng.z.yan@xxxxxxxxx>
> ---
> fs/ceph/dir.c | 12 ++++++------
> fs/ceph/super.h | 2 +-
> 2 files changed, 7 insertions(+), 7 deletions(-)
>
> diff --git a/fs/ceph/dir.c b/fs/ceph/dir.c
> index 45eda6d..a7eaf96 100644
> --- a/fs/ceph/dir.c
> +++ b/fs/ceph/dir.c
> @@ -190,7 +190,7 @@ more:
> if (last) {
> /* remember our position */
> fi->dentry = last;
> - fi->next_offset = di->offset;
> + fi->next_offset = fpos_off(di->offset);
> }
> dput(dentry);
> return 0;
> @@ -369,9 +369,9 @@ more:
> fi->next_offset = 0;
> off = fi->next_offset;
> }
> + fi->frag = frag;
> fi->offset = fi->next_offset;
> fi->last_readdir = req;
> - fi->frag = frag;
>
> if (req->r_reply_info.dir_end) {
> kfree(fi->last_name);
> @@ -474,7 +474,7 @@ static loff_t ceph_dir_llseek(struct file *file, loff_t offset, int whence)
> {
> struct ceph_file_info *fi = file->private_data;
> struct inode *inode = file->f_mapping->host;
> - loff_t old_offset = offset;
> + loff_t old_offset = ceph_make_fpos(fi->frag, fi->next_offset);
Should this be named "next_offset" (or maybe "current_offset")?
It doesn't seem "old" to me, though I do realize it doesn't
necessarily represent where the "next" file position will be.
> loff_t retval;
>
> mutex_lock(&inode->i_mutex);
> @@ -491,7 +491,7 @@ static loff_t ceph_dir_llseek(struct file *file, loff_t offset, int whence)
> goto out;
> }
>
> - if (offset >= 0 && offset <= inode->i_sb->s_maxbytes) {
> + if (offset >= 0) {
> if (offset != file->f_pos) {
> file->f_pos = offset;
> file->f_version = 0;
> @@ -504,14 +504,14 @@ static loff_t ceph_dir_llseek(struct file *file, loff_t offset, int whence)
> * seek to new frag, or seek prior to current chunk.
> */
> if (offset == 0 ||
> - fpos_frag(offset) != fpos_frag(old_offset) ||
> + fpos_frag(offset) != fi->frag ||
> fpos_off(offset) < fi->offset) {
> dout("dir_llseek dropping %p content\n", file);
> reset_readdir(fi);
> }
>
> /* bump dir_release_count if we did a forward seek */
> - if (offset > old_offset)
> + if (fpos_cmp(offset, old_offset) > 0)
> fi->dir_release_count--;
> }
> out:
> diff --git a/fs/ceph/super.h b/fs/ceph/super.h
> index d8801a9..70bb183 100644
> --- a/fs/ceph/super.h
> +++ b/fs/ceph/super.h
> @@ -577,7 +577,7 @@ struct ceph_file_info {
>
> /* readdir: position within a frag */
> unsigned offset; /* offset of last chunk, adjusted for . and .. */
> - u64 next_offset; /* offset of next chunk (last_name's + 1) */
> + unsigned next_offset; /* offset of next chunk (last_name's + 1) */
> char *last_name; /* last entry in previous chunk */
> struct dentry *dentry; /* next dentry (for dcache readdir) */
> int dir_release_count;
>
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