On Thu, 11 Apr 2019, Jeff Layton wrote:
> cephfs can definitely benefit from statx. We can just request caps
> sufficient for the attributes we need and leave off the rest.
>
> Also, recognize when AT_STATX_DONT_SYNC is set, and just scrape the
> inode without doing any call in that case. Force a call to the
> MDS in the event that AT_STATX_FORCE_SYNC is set.
Yay! I've waiting for this to fall into place for a long time. In fact,
> Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx>
> ---
> fs/ceph/inode.c | 84 ++++++++++++++++++++++++++++++++++---------------
> 1 file changed, 58 insertions(+), 26 deletions(-)
>
> diff --git a/fs/ceph/inode.c b/fs/ceph/inode.c
> index 2d61ddda9bf5..afab98ce865f 100644
> --- a/fs/ceph/inode.c
> +++ b/fs/ceph/inode.c
> @@ -2255,6 +2255,29 @@ int ceph_permission(struct inode *inode, int mask)
> return err;
> }
>
> +/*
> + * Craft a mask of needed caps given a set of requested statx attrs.
> + */
> +static int statx_to_caps(u32 want)
> +{
> + int mask = 0;
> +
> + if (want & (STATX_MODE|STATX_UID|STATX_GID|STATX_CTIME))
> + mask |= CEPH_CAP_AUTH_SHARED;
> +
> + if (want & (STATX_NLINK|STATX_CTIME))
> + mask |= CEPH_CAP_LINK_SHARED;
> +
> + if (want & (STATX_ATIME|STATX_MTIME|STATX_CTIME|STATX_SIZE|
> + STATX_BLOCKS))
> + mask |= CEPH_CAP_FILE_SHARED;
> +
> + if (want & (STATX_CTIME))
> + mask |= CEPH_CAP_XATTR_SHARED;
> +
> + return mask;
> +}
> +
> /*
> * Get all attributes. Hopefully somedata we'll have a statlite()
...this comment can finally be updated now. :)
sage
> * and can limit the fields we require to be accurate.
> @@ -2264,34 +2287,43 @@ int ceph_getattr(const struct path *path, struct kstat *stat,
> {
> struct inode *inode = d_inode(path->dentry);
> struct ceph_inode_info *ci = ceph_inode(inode);
> - int err;
> + int err = 0;
>
> - err = ceph_do_getattr(inode, CEPH_STAT_CAP_INODE_ALL, false);
> - if (!err) {
> - generic_fillattr(inode, stat);
> - stat->ino = ceph_translate_ino(inode->i_sb, inode->i_ino);
> - if (ceph_snap(inode) == CEPH_NOSNAP)
> - stat->dev = inode->i_sb->s_dev;
> - else
> - stat->dev = ci->i_snapid_map ? ci->i_snapid_map->dev : 0;
> + /* Skip the getattr altogether if we're asked not to sync */
> + if (!(flags & AT_STATX_DONT_SYNC)) {
> + err = ceph_do_getattr(inode, statx_to_caps(request_mask),
> + flags & AT_STATX_FORCE_SYNC);
> + if (err)
> + goto out;
> + }
>
> - if (S_ISDIR(inode->i_mode)) {
> - if (ceph_test_mount_opt(ceph_sb_to_client(inode->i_sb),
> - RBYTES))
> - stat->size = ci->i_rbytes;
> - else
> - stat->size = ci->i_files + ci->i_subdirs;
> - stat->blocks = 0;
> - stat->blksize = 65536;
> - /*
> - * Some applications rely on the number of st_nlink
> - * value on directories to be either 0 (if unlinked)
> - * or 2 + number of subdirectories.
> - */
> - if (stat->nlink == 1)
> - /* '.' + '..' + subdirs */
> - stat->nlink = 1 + 1 + ci->i_subdirs;
> - }
> + generic_fillattr(inode, stat);
> + stat->ino = ceph_translate_ino(inode->i_sb, inode->i_ino);
> + if (ceph_snap(inode) == CEPH_NOSNAP)
> + stat->dev = inode->i_sb->s_dev;
> + else
> + stat->dev = ci->i_snapid_map ? ci->i_snapid_map->dev : 0;
> +
> + if (S_ISDIR(inode->i_mode)) {
> + if (ceph_test_mount_opt(ceph_sb_to_client(inode->i_sb),
> + RBYTES))
> + stat->size = ci->i_rbytes;
> + else
> + stat->size = ci->i_files + ci->i_subdirs;
> + stat->blocks = 0;
> + stat->blksize = 65536;
> + /*
> + * Some applications rely on the number of st_nlink
> + * value on directories to be either 0 (if unlinked)
> + * or 2 + number of subdirectories.
> + */
> + if (stat->nlink == 1)
> + /* '.' + '..' + subdirs */
> + stat->nlink = 1 + 1 + ci->i_subdirs;
> }
> +
> + /* Mask off any higher bits (e.g. btime) until we have support */
> + stat->result_mask = request_mask & STATX_BASIC_STATS;
> +out:
> return err;
> }
> --
> 2.20.1
>
>
