Commit 794ebcea authored by Stephen Brennan's avatar Stephen Brennan Committed by Al Viro
Browse files

namei: Standardize callers of filename_lookup() 

filename_lookup() has two variants, one which drops the caller's
reference to filename (filename_lookup), and one which does
not (__filename_lookup). This can be confusing as it's unusual to drop a
caller's reference. Remove filename_lookup, rename __filename_lookup
to filename_lookup, and convert all callers. The cost is a few slightly
longer functions, but the clarity is greater.

[AV: consuming a reference is not at all unusual, actually; look at
e.g. do_mkdirat(), for example.  It's more that we want non-consuming
variant for close relative of that function...]

Link: https://lore.kernel.org/linux-fsdevel/YS+dstZ3xfcLxhoB@zeniv-ca.linux.org.uk/


Cc: Christoph Hellwig <hch@infradead.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: default avatarStephen Brennan <stephen.s.brennan@oracle.com>
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent c5f563f9

fs/fs_parser.c

+0 −1
Original line number Diff line number Diff line
@@ -165,7 +165,6 @@ int fs_lookup_param(struct fs_context *fc, 
		return invalf(fc, "%s: not usable as path", param->key);

	}



	f->refcnt++; /* filename_lookup() drops our ref. */

	ret = filename_lookup(param->dirfd, f, flags, _path, NULL);

	if (ret < 0) {

		errorf(fc, "%s: Lookup failure for '%s'", param->key, f->name);

fs/namei.c

+20 −17
Original line number Diff line number Diff line
@@ -2467,7 +2467,7 @@ static int path_lookupat(struct nameidata *nd, unsigned flags, struct path *path 
	return err;

}



static int __filename_lookup(int dfd, struct filename *name, unsigned flags,

int filename_lookup(int dfd, struct filename *name, unsigned flags,

		    struct path *path, struct path *root)

{

	int retval;
@@ -2488,15 +2488,6 @@ static int __filename_lookup(int dfd, struct filename *name, unsigned flags, 
	return retval;

}



int filename_lookup(int dfd, struct filename *name, unsigned flags,

		    struct path *path, struct path *root)

{

	int retval = __filename_lookup(dfd, name, flags, path, root);



	putname(name);

	return retval;

}



/* Returns 0 and nd will be valid on success; Retuns error, otherwise. */

static int path_parentat(struct nameidata *nd, unsigned flags,

				struct path *parent)
@@ -2573,8 +2564,12 @@ struct dentry *kern_path_locked(const char *name, struct path *path) 


int kern_path(const char *name, unsigned int flags, struct path *path)

{

	return filename_lookup(AT_FDCWD, getname_kernel(name),

			       flags, path, NULL);

	struct filename *filename = getname_kernel(name);

	int ret = filename_lookup(AT_FDCWD, filename, flags, path, NULL);



	putname(filename);

	return ret;



}

EXPORT_SYMBOL(kern_path);
@@ -2590,10 +2585,15 @@ int vfs_path_lookup(struct dentry *dentry, struct vfsmount *mnt, 
		    const char *name, unsigned int flags,

		    struct path *path)

{

	struct filename *filename;

	struct path root = {.mnt = mnt, .dentry = dentry};

	int ret;



	filename = getname_kernel(name);

	/* the first argument of filename_lookup() is ignored with root */

	return filename_lookup(AT_FDCWD, getname_kernel(name),

			       flags , path, &root);

	ret = filename_lookup(AT_FDCWD, filename, flags, path, &root);

	putname(filename);

	return ret;

}

EXPORT_SYMBOL(vfs_path_lookup);
@@ -2797,8 +2797,11 @@ int path_pts(struct path *path) 
int user_path_at_empty(int dfd, const char __user *name, unsigned flags,

		 struct path *path, int *empty)

{

	return filename_lookup(dfd, getname_flags(name, flags, empty),

			       flags, path, NULL);

	struct filename *filename = getname_flags(name, flags, empty);

	int ret = filename_lookup(dfd, filename, flags, path, NULL);



	putname(filename);

	return ret;

}

EXPORT_SYMBOL(user_path_at_empty);
@@ -4425,7 +4428,7 @@ int do_linkat(int olddfd, struct filename *old, int newdfd, 
	if (flags & AT_SYMLINK_FOLLOW)

		how |= LOOKUP_FOLLOW;

retry:

	error = __filename_lookup(olddfd, old, how, &old_path, NULL);

	error = filename_lookup(olddfd, old, how, &old_path, NULL);

	if (error)

		goto out_putnames;