On Wed 08-07-20 14:11:55, Amir Goldstein wrote:
> The fanotify_fh struct has an inline buffer of size 12 which is enough
> to store the most common local filesystem file handles (e.g. ext4, xfs).
> For file handles that do not fit in the inline buffer (e.g. btrfs), an
> external buffer is allocated to store the file handle.
>
> When allocating a variable size fanotify_name_event, there is no point
> in allocating also an external fh buffer when file handle does not fit
> in the inline buffer.
>
> Check required size for encoding fh, preallocate an event buffer
> sufficient to contain both file handle and name and store the name after
> the file handle.
>
> At this time, when not reporting name in event, we still allocate
> the fixed size fanotify_fid_event and an external buffer for large
> file handles, but fanotify_alloc_name_event() has already been prepared
> to accept a NULL file_name.
>
> Signed-off-by: Amir Goldstein <amir73il@xxxxxxxxx>
Just one tiny nit below:
> @@ -305,27 +323,34 @@ static u32 fanotify_group_event_mask(struct fsnotify_group *group,
> * Return 0 on failure to encode.
> */
> static int fanotify_encode_fh(struct fanotify_fh *fh, struct inode *inode,
> - gfp_t gfp)
> + unsigned int fh_len, gfp_t gfp)
> {
> - int dwords, type, bytes = 0;
> + int dwords, bytes, type = 0;
> char *ext_buf = NULL;
> void *buf = fh->buf;
> int err;
>
> fh->type = FILEID_ROOT;
> fh->len = 0;
> + fh->flags = 0;
> if (!inode)
> return 0;
>
> - dwords = 0;
> + /*
> + * !gpf means preallocated variable size fh, but fh_len could
> + * be zero in that case if encoding fh len failed.
> + */
> err = -ENOENT;
> - type = exportfs_encode_inode_fh(inode, NULL, &dwords, NULL);
> - if (!dwords)
> + if (!gfp)
> + bytes = fh_len;
> + else
> + bytes = fanotify_encode_fh_len(inode);
Any reason why proper fh len is not passed in by both callers? We could
then get rid of this 'if' and 'bytes' variable.
Honza
--
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR
