Commit 680baacb authored by Al Viro's avatar Al Viro
Browse files

new ->follow_link() and ->put_link() calling conventions 



a) instead of storing the symlink body (via nd_set_link()) and returning
an opaque pointer later passed to ->put_link(), ->follow_link() _stores_
that opaque pointer (into void * passed by address by caller) and returns
the symlink body.  Returning ERR_PTR() on error, NULL on jump (procfs magic
symlinks) and pointer to symlink body for normal symlinks.  Stored pointer
is ignored in all cases except the last one.

Storing NULL for opaque pointer (or not storing it at all) means no call
of ->put_link().

b) the body used to be passed to ->put_link() implicitly (via nameidata).
Now only the opaque pointer is.  In the cases when we used the symlink body
to free stuff, ->follow_link() now should store it as opaque pointer in addition
to returning it.

Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 46afd6f6

Documentation/filesystems/Locking

+2 −2
Original line number Diff line number Diff line
@@ -50,8 +50,8 @@ prototypes: 
	int (*rename2) (struct inode *, struct dentry *,

			struct inode *, struct dentry *, unsigned int);

	int (*readlink) (struct dentry *, char __user *,int);

	void * (*follow_link) (struct dentry *, struct nameidata *);

	void (*put_link) (struct dentry *, struct nameidata *, void *);

	const char *(*follow_link) (struct dentry *, void **, struct nameidata *);

	void (*put_link) (struct dentry *, void *);

	void (*truncate) (struct inode *);

	int (*permission) (struct inode *, int, unsigned int);

	int (*get_acl)(struct inode *, int);

Documentation/filesystems/vfs.txt

+2 −2
Original line number Diff line number Diff line
@@ -350,8 +350,8 @@ struct inode_operations { 
	int (*rename2) (struct inode *, struct dentry *,

			struct inode *, struct dentry *, unsigned int);

	int (*readlink) (struct dentry *, char __user *,int);

        void * (*follow_link) (struct dentry *, struct nameidata *);

        void (*put_link) (struct dentry *, struct nameidata *, void *);

	const char *(*follow_link) (struct dentry *, void **, struct nameidata *);

	void (*put_link) (struct dentry *, void *);

	int (*permission) (struct inode *, int);

	int (*get_acl)(struct inode *, int);

	int (*setattr) (struct dentry *, struct iattr *);

drivers/staging/lustre/lustre/llite/symlink.c

+5 −6
Original line number Diff line number Diff line
@@ -118,7 +118,7 @@ failed: 
	return rc;

}



static void *ll_follow_link(struct dentry *dentry, struct nameidata *nd)

static const char *ll_follow_link(struct dentry *dentry, void **cookie, struct nameidata *nd)

{

	struct inode *inode = d_inode(dentry);

	struct ptlrpc_request *request = NULL;
@@ -140,18 +140,17 @@ static void *ll_follow_link(struct dentry *dentry, struct nameidata *nd) 
	}

	if (rc) {

		ptlrpc_req_finished(request);

		request = NULL;

		symname = ERR_PTR(rc);

		return ERR_PTR(rc);

	}



	nd_set_link(nd, symname);

	/* symname may contain a pointer to the request message buffer,

	 * we delay request releasing until ll_put_link then.

	 */

	return request;

	*cookie = request;

	return symname;

}



static void ll_put_link(struct dentry *dentry, struct nameidata *nd, void *cookie)

static void ll_put_link(struct dentry *dentry, void *cookie)

{

	ptlrpc_req_finished(cookie);

}

fs/9p/vfs_inode.c

+7 −6
Original line number Diff line number Diff line
@@ -1230,11 +1230,12 @@ ino_t v9fs_qid2ino(struct p9_qid *qid) 
 *

 */



static void *v9fs_vfs_follow_link(struct dentry *dentry, struct nameidata *nd)

static const char *v9fs_vfs_follow_link(struct dentry *dentry, void **cookie, struct nameidata *nd)

{

	struct v9fs_session_info *v9ses = v9fs_dentry2v9ses(dentry);

	struct p9_fid *fid = v9fs_fid_lookup(dentry);

	struct p9_wstat *st;

	char *res;



	p9_debug(P9_DEBUG_VFS, "%pd\n", dentry);
@@ -1253,14 +1254,14 @@ static void *v9fs_vfs_follow_link(struct dentry *dentry, struct nameidata *nd) 
		kfree(st);

		return ERR_PTR(-EINVAL);

	}

	if (strlen(st->extension) >= PATH_MAX)

		st->extension[PATH_MAX - 1] = '\0';



	nd_set_link(nd, st->extension);

	res = st->extension;

	st->extension = NULL;

	if (strlen(res) >= PATH_MAX)

		res[PATH_MAX - 1] = '\0';



	p9stat_free(st);

	kfree(st);

	return NULL;

	return *cookie = res;

}



/**

fs/9p/vfs_inode_dotl.c

+3 −4
Original line number Diff line number Diff line
@@ -909,8 +909,8 @@ error: 
 *

 */



static void *

v9fs_vfs_follow_link_dotl(struct dentry *dentry, struct nameidata *nd)

static const char *

v9fs_vfs_follow_link_dotl(struct dentry *dentry, void **cookie, struct nameidata *nd)

{

	struct p9_fid *fid = v9fs_fid_lookup(dentry);

	char *target;
@@ -923,8 +923,7 @@ v9fs_vfs_follow_link_dotl(struct dentry *dentry, struct nameidata *nd) 
	retval = p9_client_readlink(fid, &target);

	if (retval)

		return ERR_PTR(retval);

	nd_set_link(nd, target);

	return NULL;

	return *cookie = target;

}



int v9fs_refresh_inode_dotl(struct p9_fid *fid, struct inode *inode)

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