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Commit 9ccee940 authored by Trond Myklebust's avatar Trond Myklebust
Browse files

Support statx() mask and query flags parameters 



Support the query flags AT_STATX_FORCE_SYNC by forcing an attribute
revalidation, and AT_STATX_DONT_SYNC by returning cached attributes
only.

Use the mask to optimise away server revalidation for attributes
that are not being requested by the user.

Signed-off-by: default avatarTrond Myklebust <trond.myklebust@primarydata.com>
parent 8634ef5e

fs/nfs/inode.c

+39 −13
Original line number Diff line number Diff line
@@ -735,12 +735,20 @@ int nfs_getattr(const struct path *path, struct kstat *stat, 
		u32 request_mask, unsigned int query_flags)

{

	struct inode *inode = d_inode(path->dentry);

	int need_atime = NFS_I(inode)->cache_validity & NFS_INO_INVALID_ATIME;

	struct nfs_server *server = NFS_SERVER(inode);

	unsigned long cache_validity;

	int err = 0;

	bool force_sync = query_flags & AT_STATX_FORCE_SYNC;

	bool do_update = false;



	trace_nfs_getattr_enter(inode);



	if ((query_flags & AT_STATX_DONT_SYNC) && !force_sync)

		goto out_no_update;



	/* Flush out writes to the server in order to update c/mtime.  */

	if (S_ISREG(inode->i_mode)) {

	if ((request_mask & (STATX_CTIME|STATX_MTIME)) &&

			S_ISREG(inode->i_mode)) {

		err = filemap_write_and_wait(inode->i_mapping);

		if (err)

			goto out;
@@ -757,24 +765,42 @@ int nfs_getattr(const struct path *path, struct kstat *stat, 
	 */

	if ((path->mnt->mnt_flags & MNT_NOATIME) ||

	    ((path->mnt->mnt_flags & MNT_NODIRATIME) && S_ISDIR(inode->i_mode)))

		need_atime = 0;



	if (need_atime || nfs_need_revalidate_inode(inode)) {

		struct nfs_server *server = NFS_SERVER(inode);



		request_mask &= ~STATX_ATIME;



	/* Is the user requesting attributes that might need revalidation? */

	if (!(request_mask & (STATX_MODE|STATX_NLINK|STATX_ATIME|STATX_CTIME|

					STATX_MTIME|STATX_UID|STATX_GID|

					STATX_SIZE|STATX_BLOCKS)))

		goto out_no_revalidate;



	/* Check whether the cached attributes are stale */

	do_update |= force_sync || nfs_attribute_cache_expired(inode);

	cache_validity = READ_ONCE(NFS_I(inode)->cache_validity);

	do_update |= cache_validity &

		(NFS_INO_INVALID_ATTR|NFS_INO_INVALID_LABEL);

	if (request_mask & STATX_ATIME)

		do_update |= cache_validity & NFS_INO_INVALID_ATIME;

	if (request_mask & (STATX_CTIME|STATX_MTIME))

		do_update |= cache_validity & NFS_INO_REVAL_PAGECACHE;

	if (do_update) {

		/* Update the attribute cache */

		if (!(server->flags & NFS_MOUNT_NOAC))

			nfs_readdirplus_parent_cache_miss(path->dentry);

		else

			nfs_readdirplus_parent_cache_hit(path->dentry);

		err = __nfs_revalidate_inode(server, inode);

		if (err)

			goto out;

	} else

		nfs_readdirplus_parent_cache_hit(path->dentry);

	if (!err) {

out_no_revalidate:

	/* Only return attributes that were revalidated. */

	stat->result_mask &= request_mask;

out_no_update:

	generic_fillattr(inode, stat);

	stat->ino = nfs_compat_user_ino64(NFS_FILEID(inode));

	if (S_ISDIR(inode->i_mode))

		stat->blksize = NFS_SERVER(inode)->dtsize;

	}

out:

	trace_nfs_getattr_exit(inode, err);

	return err;