Re: [PATCH 3/7] sysfs: Keep an nlink count on sysfs directories.

Cornelia Huck
2010-01-12T12:40:54Z

On Mon, 11 Jan 2010 12:21:51 -0800,
"Eric W. Biederman" <ebiederm@xmission.com> wrote:

> From: Eric W. Biederman <ebiederm@aristanetworks.com>
>
> On large directories sysfs_count_nlinks can be a significant
> bottleneck, so keep a count in sysfs_dirent. If we exceed
> the maximum number of directory entries we can store return
> nlink of 1. An nlink of 1 matches what reiserfs does in
> this case, and it let's find and similar utlities know that
> we have a the directory nlink can not be used for optimization
> purposes.
>
> Signed-off-by: Eric W. Biederman <ebiederm@aristanetworks.com>
> ---
> fs/sysfs/dir.c | 20 ++++++++++++++++++++
> fs/sysfs/inode.c | 15 +--------------
> fs/sysfs/mount.c | 1 +
> fs/sysfs/sysfs.h | 1 +
> 4 files changed, 23 insertions(+), 14 deletions(-)
>

> @@ -420,6 +438,7 @@ int __sysfs_add_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd)
> return -EEXIST;
>
> sd->s_parent = sysfs_get(acxt->parent_sd);
> + sysfs_dir_inc_nlink(sd->s_parent);
>
> sysfs_link_sibling(sd);
>
> @@ -512,6 +531,7 @@ void sysfs_remove_one(struct sysfs_addrm_cxt *acxt, struct sysfs_dirent *sd)
>
> BUG_ON(sd->s_flags & SYSFS_FLAG_REMOVED);
>
> + sysfs_dir_dec_nlink(sd->s_parent);
> sysfs_unlink_sibling(sd);
>
> /* Update timestamps on the parent */

Shouldn't s_nlink be adjusted in sysfs_rename for the move case as well?