Commit 949a852e authored by Al Viro's avatar Al Viro
Browse files

namei: teach lookup_slow() to skip revalidate 



... and make mountpoint_last() use it.  That makes all
candidates for lookup with parent locked shared go
through lookup_slow().

Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent e3c13928

fs/namei.c

+35 −23
Original line number Diff line number Diff line
@@ -1605,7 +1605,29 @@ static struct dentry *lookup_slow(const struct qstr *name, 
{

	struct dentry *dentry;

	inode_lock(dir->d_inode);

	dentry = __lookup_hash(name, dir, flags);

	dentry = d_lookup(dir, name);

	if (unlikely(dentry)) {

		if ((dentry->d_flags & DCACHE_OP_REVALIDATE) &&

		    !(flags & LOOKUP_NO_REVAL)) {

			int error = d_revalidate(dentry, flags);

			if (unlikely(error <= 0)) {

				if (!error)

					d_invalidate(dentry);

				dput(dentry);

				dentry = ERR_PTR(error);

			}

		}

		if (dentry) {

			inode_unlock(dir->d_inode);

			return dentry;

		}

	}

	dentry = d_alloc(dir, name);

	if (unlikely(!dentry)) {

		inode_unlock(dir->d_inode);

		return ERR_PTR(-ENOMEM);

	}

	dentry = lookup_real(dir->d_inode, dentry, flags);

	inode_unlock(dir->d_inode);

	return dentry;

}
@@ -2425,31 +2447,21 @@ mountpoint_last(struct nameidata *nd, struct path *path) 
		if (error)

			return error;

		dentry = dget(nd->path.dentry);

		goto done;

	}



	inode_lock(dir->d_inode);

	} else {

		dentry = d_lookup(dir, &nd->last);

		if (!dentry) {

			/*

		 * No cached dentry. Mounted dentries are pinned in the cache,

		 * so that means that this dentry is probably a symlink or the

		 * path doesn't actually point to a mounted dentry.

			 * No cached dentry. Mounted dentries are pinned in the

			 * cache, so that means that this dentry is probably

			 * a symlink or the path doesn't actually point

			 * to a mounted dentry.

			 */

		dentry = d_alloc(dir, &nd->last);

		if (!dentry) {

			inode_unlock(dir->d_inode);

			return -ENOMEM;

		}

		dentry = lookup_real(dir->d_inode, dentry, nd->flags);

		if (IS_ERR(dentry)) {

			inode_unlock(dir->d_inode);

			dentry = lookup_slow(&nd->last, dir,

					     nd->flags | LOOKUP_NO_REVAL);

			if (IS_ERR(dentry))

				return PTR_ERR(dentry);

		}

	}

	inode_unlock(dir->d_inode);



done:

	if (d_is_negative(dentry)) {

		dput(dentry);

		return -ENOENT;

include/linux/namei.h

+1 −0
Original line number Diff line number Diff line
@@ -31,6 +31,7 @@ enum {LAST_NORM, LAST_ROOT, LAST_DOT, LAST_DOTDOT, LAST_BIND}; 
#define LOOKUP_PARENT		0x0010

#define LOOKUP_REVAL		0x0020

#define LOOKUP_RCU		0x0040

#define LOOKUP_NO_REVAL		0x0080



/*

 * Intent data