Merge branch 'work.symlinks' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

Pull vfs RCU symlink updates from Al Viro:
 "Replacement of ->follow_link/->put_link, allowing to stay in RCU mode
  even if the symlink is not an embedded one.

  No changes since the mailbomb on Jan 1"

* 'work.symlinks' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  switch ->get_link() to delayed_call, kill ->put_link()
  kill free_page_put_link()
  teach nfs_get_link() to work in RCU mode
  teach proc_self_get_link()/proc_thread_self_get_link() to work in RCU mode
  teach shmem_get_link() to work in RCU mode
  teach page_get_link() to work in RCU mode
  replace ->follow_link() with new method that could stay in RCU mode
  don't put symlink bodies in pagecache into highmem
  namei: page_getlink() and page_follow_link_light() are the same thing
  ufs: get rid of ->setattr() for symlinks
  udf: don't duplicate page_symlink_inode_operations
  logfs: don't duplicate page_symlink_inode_operations
  switch befs long symlinks to page_symlink_operations

Documentation/filesystems/Locking

@@ -50,8 +50,7 @@ prototypes:
 	int (*rename2) (struct inode *, struct dentry *,
 			struct inode *, struct dentry *, unsigned int);
 	int (*readlink) (struct dentry *, char __user *,int);
-	const char *(*follow_link) (struct dentry *, void **);
-	void (*put_link) (struct inode *, void *);
+	const char *(*get_link) (struct dentry *, struct inode *, void **);
 	void (*truncate) (struct inode *);
 	int (*permission) (struct inode *, int, unsigned int);
 	int (*get_acl)(struct inode *, int);
@@ -83,8 +82,7 @@ rmdir:		yes (both)	(see below)
 rename:		yes (all)	(see below)
 rename2:	yes (all)	(see below)
 readlink:	no
-follow_link:	no
-put_link:	no
+get_link:	no
 setattr:	yes
 permission:	no (may not block if called in rcu-walk mode)
 get_acl:	no

Documentation/filesystems/porting

@@ -504,3 +504,20 @@ in your dentry operations instead.
 [mandatory]
 	__fd_install() & fd_install() can now sleep. Callers should not
 	hold a spinlock	or other resources that do not allow a schedule.
+--
+[mandatory]
+	any symlink that might use page_follow_link_light/page_put_link() must
+	have inode_nohighmem(inode) called before anything might start playing with
+	its pagecache.
+--
+[mandatory]
+	->follow_link() is replaced with ->get_link(); same API, except that
+		* ->get_link() gets inode as a separate argument
+		* ->get_link() may be called in RCU mode - in that case NULL
+		  dentry is passed
+--
+[mandatory]
+	->get_link() gets struct delayed_call *done now, and should do
+	set_delayed_call() where it used to set *cookie.
+	->put_link() is gone - just give the destructor to set_delayed_call()
+	in ->get_link().

Documentation/filesystems/vfs.txt

@@ -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);
-	const char *(*follow_link) (struct dentry *, void **);
-	void (*put_link) (struct inode *, void *);
+	const char *(*get_link) (struct dentry *, struct inode *,
+				 struct delayed_call *);
 	int (*permission) (struct inode *, int);
 	int (*get_acl)(struct inode *, int);
 	int (*setattr) (struct dentry *, struct iattr *);
@@ -434,20 +434,19 @@ otherwise noted.
   readlink: called by the readlink(2) system call. Only required if
 	you want to support reading symbolic links
 
-  follow_link: called by the VFS to follow a symbolic link to the
+  get_link: called by the VFS to follow a symbolic link to the
 	inode it points to.  Only required if you want to support
 	symbolic links.  This method returns the symlink body
 	to traverse (and possibly resets the current position with
 	nd_jump_link()).  If the body won't go away until the inode
 	is gone, nothing else is needed; if it needs to be otherwise
-	pinned, the data needed to release whatever we'd grabbed
-	is to be stored in void * variable passed by address to
-	follow_link() instance.
-
-  put_link: called by the VFS to release resources allocated by
-	follow_link().  The cookie stored by follow_link() is passed
-	to this method as the last parameter; only called when
-	cookie isn't NULL.
+	pinned, arrange for its release by having get_link(..., ..., done)
+	do set_delayed_call(done, destructor, argument).
+	In that case destructor(argument) will be called once VFS is
+	done with the body you've returned.
+	May be called in RCU mode; that is indicated by NULL dentry
+	argument.  If request can't be handled without leaving RCU mode,
+	have it return ERR_PTR(-ECHILD).
 
   permission: called by the VFS to check for access rights on a POSIX-like
   	filesystem.

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

@@ -118,12 +118,20 @@ failed:
 	return rc;
 }
 
-static const char *ll_follow_link(struct dentry *dentry, void **cookie)
+static void ll_put_link(void *p)
+{
+	ptlrpc_req_finished(p);
+}
+
+static const char *ll_get_link(struct dentry *dentry,
+			       struct inode *inode,
+			       struct delayed_call *done)
 {
-	struct inode *inode = d_inode(dentry);
 	struct ptlrpc_request *request = NULL;
 	int rc;
 	char *symname = NULL;
+	if (!dentry)
+		return ERR_PTR(-ECHILD);
 
 	CDEBUG(D_VFSTRACE, "VFS Op\n");
 	ll_inode_size_lock(inode);
@@ -135,22 +143,16 @@ static const char *ll_follow_link(struct dentry *dentry, void **cookie)
 	}
 
 	/* symname may contain a pointer to the request message buffer,
-	 * we delay request releasing until ll_put_link then.
+	 * we delay request releasing then.
 	 */
-	*cookie = request;
+	set_delayed_call(done, ll_put_link, request);
 	return symname;
 }
 
-static void ll_put_link(struct inode *unused, void *cookie)
-{
-	ptlrpc_req_finished(cookie);
-}
-
 struct inode_operations ll_fast_symlink_inode_operations = {
 	.readlink	= generic_readlink,
 	.setattr	= ll_setattr,
-	.follow_link	= ll_follow_link,
-	.put_link	= ll_put_link,
+	.get_link	= ll_get_link,
 	.getattr	= ll_getattr,
 	.permission	= ll_inode_permission,
 	.setxattr	= ll_setxattr,

fs/9p/vfs_inode.c

@@ -1223,18 +1223,26 @@ ino_t v9fs_qid2ino(struct p9_qid *qid)
 }
 
 /**
- * v9fs_vfs_follow_link - follow a symlink path
+ * v9fs_vfs_get_link - follow a symlink path
  * @dentry: dentry for symlink
- * @cookie: place to pass the data to put_link()
+ * @inode: inode for symlink
+ * @done: delayed call for when we are done with the return value
  */
 
-static const char *v9fs_vfs_follow_link(struct dentry *dentry, void **cookie)
+static const char *v9fs_vfs_get_link(struct dentry *dentry,
+				     struct inode *inode,
+				     struct delayed_call *done)
 {
-	struct v9fs_session_info *v9ses = v9fs_dentry2v9ses(dentry);
-	struct p9_fid *fid = v9fs_fid_lookup(dentry);
+	struct v9fs_session_info *v9ses;
+	struct p9_fid *fid;
 	struct p9_wstat *st;
 	char *res;
 
+	if (!dentry)
+		return ERR_PTR(-ECHILD);
+
+	v9ses = v9fs_dentry2v9ses(dentry);
+	fid = v9fs_fid_lookup(dentry);
 	p9_debug(P9_DEBUG_VFS, "%pd\n", dentry);
 
 	if (IS_ERR(fid))
@@ -1259,7 +1267,8 @@ static const char *v9fs_vfs_follow_link(struct dentry *dentry, void **cookie)
 
 	p9stat_free(st);
 	kfree(st);
-	return *cookie = res;
+	set_delayed_call(done, kfree_link, res);
+	return res;
 }
 
 /**
@@ -1452,8 +1461,7 @@ static const struct inode_operations v9fs_file_inode_operations = {
 
 static const struct inode_operations v9fs_symlink_inode_operations = {
 	.readlink = generic_readlink,
-	.follow_link = v9fs_vfs_follow_link,
-	.put_link = kfree_put_link,
+	.get_link = v9fs_vfs_get_link,
 	.getattr = v9fs_vfs_getattr,
 	.setattr = v9fs_vfs_setattr,
 };

fs/9p/vfs_inode_dotl.c

@@ -899,26 +899,34 @@ error:
 }
 
 /**
- * v9fs_vfs_follow_link_dotl - follow a symlink path
+ * v9fs_vfs_get_link_dotl - follow a symlink path
  * @dentry: dentry for symlink
- * @cookie: place to pass the data to put_link()
+ * @inode: inode for symlink
+ * @done: destructor for return value
  */
 
 static const char *
-v9fs_vfs_follow_link_dotl(struct dentry *dentry, void **cookie)
+v9fs_vfs_get_link_dotl(struct dentry *dentry,
+		       struct inode *inode,
+		       struct delayed_call *done)
 {
-	struct p9_fid *fid = v9fs_fid_lookup(dentry);
+	struct p9_fid *fid;
 	char *target;
 	int retval;
 
+	if (!dentry)
+		return ERR_PTR(-ECHILD);
+
 	p9_debug(P9_DEBUG_VFS, "%pd\n", dentry);
 
+	fid = v9fs_fid_lookup(dentry);
 	if (IS_ERR(fid))
 		return ERR_CAST(fid);
 	retval = p9_client_readlink(fid, &target);
 	if (retval)
 		return ERR_PTR(retval);
-	return *cookie = target;
+	set_delayed_call(done, kfree_link, target);
+	return target;
 }
 
 int v9fs_refresh_inode_dotl(struct p9_fid *fid, struct inode *inode)
@@ -984,8 +992,7 @@ const struct inode_operations v9fs_file_inode_operations_dotl = {
 
 const struct inode_operations v9fs_symlink_inode_operations_dotl = {
 	.readlink = generic_readlink,
-	.follow_link = v9fs_vfs_follow_link_dotl,
-	.put_link = kfree_put_link,
+	.get_link = v9fs_vfs_get_link_dotl,
 	.getattr = v9fs_vfs_getattr_dotl,
 	.setattr = v9fs_vfs_setattr_dotl,
 	.setxattr = generic_setxattr,

fs/affs/inode.c

@@ -140,6 +140,7 @@ struct inode *affs_iget(struct super_block *sb, unsigned long ino)
 		break;
 	case ST_SOFTLINK:
 		inode->i_mode |= S_IFLNK;
+		inode_nohighmem(inode);
 		inode->i_op = &affs_symlink_inode_operations;
 		inode->i_data.a_ops = &affs_symlink_aops;
 		break;

fs/affs/namei.c

@@ -344,6 +344,7 @@ affs_symlink(struct inode *dir, struct dentry *dentry, const char *symname)
 		return -ENOSPC;
 
 	inode->i_op = &affs_symlink_inode_operations;
+	inode_nohighmem(inode);
 	inode->i_data.a_ops = &affs_symlink_aops;
 	inode->i_mode = S_IFLNK | 0777;
 	mode_to_prot(inode);

fs/affs/symlink.c

@@ -14,13 +14,13 @@ static int affs_symlink_readpage(struct file *file, struct page *page)
 {
 	struct buffer_head *bh;
 	struct inode *inode = page->mapping->host;
-	char *link = kmap(page);
+	char *link = page_address(page);
 	struct slink_front *lf;
 	int			 i, j;
 	char			 c;
 	char			 lc;
 
-	pr_debug("follow_link(ino=%lu)\n", inode->i_ino);
+	pr_debug("get_link(ino=%lu)\n", inode->i_ino);
 
 	bh = affs_bread(inode->i_sb, inode->i_ino);
 	if (!bh)
@@ -57,12 +57,10 @@ static int affs_symlink_readpage(struct file *file, struct page *page)
 	link[i] = '\0';
 	affs_brelse(bh);
 	SetPageUptodate(page);
-	kunmap(page);
 	unlock_page(page);
 	return 0;
 fail:
 	SetPageError(page);
-	kunmap(page);
 	unlock_page(page);
 	return -EIO;
 }
@@ -73,7 +71,6 @@ const struct address_space_operations affs_symlink_aops = {
 
 const struct inode_operations affs_symlink_inode_operations = {
 	.readlink	= generic_readlink,
-	.follow_link	= page_follow_link_light,
-	.put_link	= page_put_link,
+	.get_link	= page_get_link,
 	.setattr	= affs_notify_change,
 };

fs/afs/inode.c

@@ -56,6 +56,7 @@ static int afs_inode_map_status(struct afs_vnode *vnode, struct key *key)
 	case AFS_FTYPE_SYMLINK:
 		inode->i_mode	= S_IFLNK | vnode->status.mode;
 		inode->i_op	= &page_symlink_inode_operations;
+		inode_nohighmem(inode);
 		break;
 	default:
 		printk("kAFS: AFS vnode with undefined type\n");

fs/autofs4/symlink.c

@@ -12,10 +12,16 @@
 
 #include "autofs_i.h"
 
-static const char *autofs4_follow_link(struct dentry *dentry, void **cookie)
+static const char *autofs4_get_link(struct dentry *dentry,
+				    struct inode *inode,
+				    struct delayed_call *done)
 {
-	struct autofs_sb_info *sbi = autofs4_sbi(dentry->d_sb);
-	struct autofs_info *ino = autofs4_dentry_ino(dentry);
+	struct autofs_sb_info *sbi;
+	struct autofs_info *ino;
+	if (!dentry)
+		return ERR_PTR(-ECHILD);
+	sbi = autofs4_sbi(dentry->d_sb);
+	ino = autofs4_dentry_ino(dentry);
 	if (ino && !autofs4_oz_mode(sbi))
 		ino->last_used = jiffies;
 	return d_inode(dentry)->i_private;
@@ -23,5 +29,5 @@ static const char *autofs4_follow_link(struct dentry *dentry, void **cookie)
 
 const struct inode_operations autofs4_symlink_inode_operations = {
 	.readlink	= generic_readlink,
-	.follow_link	= autofs4_follow_link
+	.get_link	= autofs4_get_link
 };

fs/befs/linuxvfs.c

@@ -42,7 +42,7 @@ static struct inode *befs_iget(struct super_block *, unsigned long);
 static struct inode *befs_alloc_inode(struct super_block *sb);
 static void befs_destroy_inode(struct inode *inode);
 static void befs_destroy_inodecache(void);
-static const char *befs_follow_link(struct dentry *, void **);
+static int befs_symlink_readpage(struct file *, struct page *);
 static int befs_utf2nls(struct super_block *sb, const char *in, int in_len,
 			char **out, int *out_len);
 static int befs_nls2utf(struct super_block *sb, const char *in, int in_len,
@@ -79,10 +79,8 @@ static const struct address_space_operations befs_aops = {
 	.bmap		= befs_bmap,
 };
 
-static const struct inode_operations befs_symlink_inode_operations = {
-	.readlink	= generic_readlink,
-	.follow_link	= befs_follow_link,
-	.put_link	= kfree_put_link,
+static const struct address_space_operations befs_symlink_aops = {
+	.readpage	= befs_symlink_readpage,
 };
 
 /* 
@@ -398,7 +396,9 @@ static struct inode *befs_iget(struct super_block *sb, unsigned long ino)
 		inode->i_fop = &befs_dir_operations;
 	} else if (S_ISLNK(inode->i_mode)) {
 		if (befs_ino->i_flags & BEFS_LONG_SYMLINK) {
-			inode->i_op = &befs_symlink_inode_operations;
+			inode->i_op = &page_symlink_inode_operations;
+			inode_nohighmem(inode);
+			inode->i_mapping->a_ops = &befs_symlink_aops;
 		} else {
 			inode->i_link = befs_ino->i_data.symlink;
 			inode->i_op = &simple_symlink_inode_operations;
@@ -463,31 +463,33 @@ befs_destroy_inodecache(void)
  * The data stream become link name. Unless the LONG_SYMLINK
  * flag is set.
  */
-static const char *
-befs_follow_link(struct dentry *dentry, void **cookie)
+static int befs_symlink_readpage(struct file *unused, struct page *page)
 {
-	struct super_block *sb = dentry->d_sb;
-	struct befs_inode_info *befs_ino = BEFS_I(d_inode(dentry));
+	struct inode *inode = page->mapping->host;
+	struct super_block *sb = inode->i_sb;
+	struct befs_inode_info *befs_ino = BEFS_I(inode);
 	befs_data_stream *data = &befs_ino->i_data.ds;
 	befs_off_t len = data->size;
-	char *link;
+	char *link = page_address(page);
 
-	if (len == 0) {
+	if (len == 0 || len > PAGE_SIZE) {
 		befs_error(sb, "Long symlink with illegal length");
-		return ERR_PTR(-EIO);
+		goto fail;
 	}
 	befs_debug(sb, "Follow long symlink");
 
-	link = kmalloc(len, GFP_NOFS);
-	if (!link)
-		return ERR_PTR(-ENOMEM);
 	if (befs_read_lsymlink(sb, data, link, len) != len) {
-		kfree(link);
 		befs_error(sb, "Failed to read entire long symlink");
-		return ERR_PTR(-EIO);
+		goto fail;
 	}
 	link[len - 1] = '\0';
-	return *cookie = link;
+	SetPageUptodate(page);
+	unlock_page(page);
+	return 0;
+fail:
+	SetPageError(page);
+	unlock_page(page);
+	return -EIO;
 }
 
 /*

fs/btrfs/inode.c

@@ -3774,6 +3774,7 @@ cache_acl:
 		break;
 	case S_IFLNK:
 		inode->i_op = &btrfs_symlink_inode_operations;
+		inode_nohighmem(inode);
 		inode->i_mapping->a_ops = &btrfs_symlink_aops;
 		break;
 	default:
@@ -9705,6 +9706,7 @@ static int btrfs_symlink(struct inode *dir, struct dentry *dentry,
 	btrfs_free_path(path);
 
 	inode->i_op = &btrfs_symlink_inode_operations;
+	inode_nohighmem(inode);
 	inode->i_mapping->a_ops = &btrfs_symlink_aops;
 	inode_set_bytes(inode, name_len);
 	btrfs_i_size_write(inode, name_len);
@@ -10094,8 +10096,7 @@ static const struct inode_operations btrfs_special_inode_operations = {
 };
 static const struct inode_operations btrfs_symlink_inode_operations = {
 	.readlink	= generic_readlink,
-	.follow_link	= page_follow_link_light,
-	.put_link	= page_put_link,
+	.get_link	= page_get_link,
 	.getattr	= btrfs_getattr,
 	.setattr	= btrfs_setattr,
 	.permission	= btrfs_permission,

fs/ceph/inode.c

@@ -1756,7 +1756,7 @@ retry:
  */
 static const struct inode_operations ceph_symlink_iops = {
 	.readlink = generic_readlink,
-	.follow_link = simple_follow_link,
+	.get_link = simple_get_link,
 	.setattr = ceph_setattr,
 	.getattr = ceph_getattr,
 	.setxattr = ceph_setxattr,

fs/cifs/cifsfs.c

@@ -900,8 +900,7 @@ const struct inode_operations cifs_file_inode_ops = {
 
 const struct inode_operations cifs_symlink_inode_ops = {
 	.readlink = generic_readlink,
-	.follow_link = cifs_follow_link,
-	.put_link = kfree_put_link,
+	.get_link = cifs_get_link,
 	.permission = cifs_permission,
 	/* BB add the following two eventually */
 	/* revalidate: cifs_revalidate,

fs/cifs/cifsfs.h

@@ -120,9 +120,8 @@ extern struct vfsmount *cifs_dfs_d_automount(struct path *path);
 #endif
 
 /* Functions related to symlinks */
-extern const char *cifs_follow_link(struct dentry *direntry, void **cookie);
-extern int cifs_readlink(struct dentry *direntry, char __user *buffer,
-			 int buflen);
+extern const char *cifs_get_link(struct dentry *, struct inode *,
+			struct delayed_call *);
 extern int cifs_symlink(struct inode *inode, struct dentry *direntry,
 			const char *symname);
 extern int	cifs_removexattr(struct dentry *, const char *);

fs/cifs/link.c

@@ -627,9 +627,9 @@ cifs_hl_exit:
 }
 
 const char *
-cifs_follow_link(struct dentry *direntry, void **cookie)
+cifs_get_link(struct dentry *direntry, struct inode *inode,
+	      struct delayed_call *done)
 {
-	struct inode *inode = d_inode(direntry);
 	int rc = -ENOMEM;
 	unsigned int xid;
 	char *full_path = NULL;
@@ -639,6 +639,9 @@ cifs_follow_link(struct dentry *direntry, void **cookie)
 	struct cifs_tcon *tcon;
 	struct TCP_Server_Info *server;
 
+	if (!direntry)
+		return ERR_PTR(-ECHILD);
+
 	xid = get_xid();
 
 	tlink = cifs_sb_tlink(cifs_sb);
@@ -678,7 +681,8 @@ cifs_follow_link(struct dentry *direntry, void **cookie)
 		kfree(target_path);
 		return ERR_PTR(rc);
 	}
-	return *cookie = target_path;
+	set_delayed_call(done, kfree_link, target_path);
+	return target_path;
 }
 
 int

fs/coda/cnode.c

@@ -8,6 +8,7 @@
 
 #include <linux/coda.h>
 #include <linux/coda_psdev.h>
+#include <linux/pagemap.h>
 #include "coda_linux.h"
 
 static inline int coda_fideq(struct CodaFid *fid1, struct CodaFid *fid2)
@@ -17,8 +18,7 @@ static inline int coda_fideq(struct CodaFid *fid1, struct CodaFid *fid2)
 
 static const struct inode_operations coda_symlink_inode_operations = {
 	.readlink	= generic_readlink,
-	.follow_link	= page_follow_link_light,
-	.put_link	= page_put_link,
+	.get_link	= page_get_link,
 	.setattr	= coda_setattr,
 };
 
@@ -35,6 +35,7 @@ static void coda_fill_inode(struct inode *inode, struct coda_vattr *attr)
                 inode->i_fop = &coda_dir_operations;
         } else if (S_ISLNK(inode->i_mode)) {
 		inode->i_op = &coda_symlink_inode_operations;
+		inode_nohighmem(inode);
 		inode->i_data.a_ops = &coda_symlink_aops;
 		inode->i_mapping = &inode->i_data;
 	} else

fs/coda/symlink.c

@@ -26,7 +26,7 @@ static int coda_symlink_filler(struct file *file, struct page *page)
 	int error;
 	struct coda_inode_info *cii;
 	unsigned int len = PAGE_SIZE;
-	char *p = kmap(page);
+	char *p = page_address(page);
 
 	cii = ITOC(inode);
 
@@ -34,13 +34,11 @@ static int coda_symlink_filler(struct file *file, struct page *page)
 	if (error)
 		goto fail;
 	SetPageUptodate(page);
-	kunmap(page);
 	unlock_page(page);
 	return 0;
 
 fail:
 	SetPageError(page);
-	kunmap(page);
 	unlock_page(page);
 	return error;
 }

fs/configfs/symlink.c

@@ -279,27 +279,33 @@ static int configfs_getlink(struct dentry *dentry, char * path)
 
 }
 
-static const char *configfs_follow_link(struct dentry *dentry, void **cookie)
+static const char *configfs_get_link(struct dentry *dentry,
+				     struct inode *inode,
+				     struct delayed_call *done)
 {
-	unsigned long page = get_zeroed_page(GFP_KERNEL);
+	char *body;
 	int error;
 
-	if (!page)
+	if (!dentry)
+		return ERR_PTR(-ECHILD);
+
+	body = kzalloc(PAGE_SIZE, GFP_KERNEL);
+	if (!body)
 		return ERR_PTR(-ENOMEM);
 
-	error = configfs_getlink(dentry, (char *)page);
+	error = configfs_getlink(dentry, body);
 	if (!error) {
-		return *cookie = (void *)page;
+		set_delayed_call(done, kfree_link, body);
+		return body;
 	}
 
-	free_page(page);
+	kfree(body);
 	return ERR_PTR(error);
 }
 
 const struct inode_operations configfs_symlink_inode_operations = {
-	.follow_link = configfs_follow_link,
+	.get_link = configfs_get_link,
 	.readlink = generic_readlink,
-	.put_link = free_page_put_link,
 	.setattr = configfs_setattr,
 };
 

fs/cramfs/inode.c

@@ -100,6 +100,7 @@ static struct inode *get_cramfs_inode(struct super_block *sb,
 		break;
 	case S_IFLNK:
 		inode->i_op = &page_symlink_inode_operations;
+		inode_nohighmem(inode);
 		inode->i_data.a_ops = &cramfs_aops;
 		break;
 	default:

fs/dcache.c

@@ -1734,7 +1734,7 @@ static unsigned d_flags_for_inode(struct inode *inode)
 	}
 
 	if (unlikely(!(inode->i_opflags & IOP_NOFOLLOW))) {
-		if (unlikely(inode->i_op->follow_link)) {
+		if (unlikely(inode->i_op->get_link)) {
 			add_flags = DCACHE_SYMLINK_TYPE;
 			goto type_determined;
 		}

fs/ecryptfs/inode.c

@@ -674,16 +674,24 @@ out:
 	return rc ? ERR_PTR(rc) : buf;
 }
 
-static const char *ecryptfs_follow_link(struct dentry *dentry, void **cookie)
+static const char *ecryptfs_get_link(struct dentry *dentry,
+				     struct inode *inode,
+				     struct delayed_call *done)
 {
 	size_t len;
-	char *buf = ecryptfs_readlink_lower(dentry, &len);
+	char *buf;
+
+	if (!dentry)
+		return ERR_PTR(-ECHILD);
+
+	buf = ecryptfs_readlink_lower(dentry, &len);
 	if (IS_ERR(buf))
 		return buf;
 	fsstack_copy_attr_atime(d_inode(dentry),
 				d_inode(ecryptfs_dentry_to_lower(dentry)));
 	buf[len] = '\0';
-	return *cookie = buf;
+	set_delayed_call(done, kfree_link, buf);
+	return buf;
 }
 
 /**
@@ -1095,8 +1103,7 @@ out:
 
 const struct inode_operations ecryptfs_symlink_iops = {
 	.readlink = generic_readlink,
-	.follow_link = ecryptfs_follow_link,
-	.put_link = kfree_put_link,
+	.get_link = ecryptfs_get_link,
 	.permission = ecryptfs_permission,
 	.setattr = ecryptfs_setattr,
 	.getattr = ecryptfs_getattr_link,

fs/efs/inode.c

@@ -151,6 +151,7 @@ struct inode *efs_iget(struct super_block *super, unsigned long ino)
 			break;
 		case S_IFLNK:
 			inode->i_op = &page_symlink_inode_operations;
+			inode_nohighmem(inode);
 			inode->i_data.a_ops = &efs_symlink_aops;
 			break;
 		case S_IFCHR:

fs/efs/symlink.c

@@ -13,7 +13,7 @@
 
 static int efs_symlink_readpage(struct file *file, struct page *page)
 {
-	char *link = kmap(page);
+	char *link = page_address(page);
 	struct buffer_head * bh;
 	struct inode * inode = page->mapping->host;
 	efs_block_t size = inode->i_size;
@@ -39,12 +39,10 @@ static int efs_symlink_readpage(struct file *file, struct page *page)
 	}
 	link[size] = '\0';
 	SetPageUptodate(page);
-	kunmap(page);
 	unlock_page(page);
 	return 0;
 fail:
 	SetPageError(page);
-	kunmap(page);
 	unlock_page(page);
 	return err;
 }

fs/exofs/inode.c

@@ -1224,6 +1224,7 @@ struct inode *exofs_iget(struct super_block *sb, unsigned long ino)
 			inode->i_link = (char *)oi->i_data;
 		} else {
 			inode->i_op = &page_symlink_inode_operations;
+			inode_nohighmem(inode);
 			inode->i_mapping->a_ops = &exofs_aops;
 		}
 	} else {

fs/exofs/namei.c

@@ -111,6 +111,7 @@ static int exofs_symlink(struct inode *dir, struct dentry *dentry,
 	if (l > sizeof(oi->i_data)) {
 		/* slow symlink */
 		inode->i_op = &page_symlink_inode_operations;
+		inode_nohighmem(inode);
 		inode->i_mapping->a_ops = &exofs_aops;
 		memset(oi->i_data, 0, sizeof(oi->i_data));
 

fs/ext2/inode.c

@@ -1420,6 +1420,7 @@ struct inode *ext2_iget (struct super_block *sb, unsigned long ino)
 				sizeof(ei->i_data) - 1);
 		} else {
 			inode->i_op = &ext2_symlink_inode_operations;
+			inode_nohighmem(inode);
 			if (test_opt(inode->i_sb, NOBH))
 				inode->i_mapping->a_ops = &ext2_nobh_aops;
 			else

fs/ext2/namei.c

@@ -183,6 +183,7 @@ static int ext2_symlink (struct inode * dir, struct dentry * dentry,
 	if (l > sizeof (EXT2_I(inode)->i_data)) {
 		/* slow symlink */
 		inode->i_op = &ext2_symlink_inode_operations;
+		inode_nohighmem(inode);
 		if (test_opt(inode->i_sb, NOBH))
 			inode->i_mapping->a_ops = &ext2_nobh_aops;
 		else

fs/ext2/symlink.c

@@ -22,8 +22,7 @@
 
 const struct inode_operations ext2_symlink_inode_operations = {
 	.readlink	= generic_readlink,
-	.follow_link	= page_follow_link_light,
-	.put_link	= page_put_link,
+	.get_link	= page_get_link,
 	.setattr	= ext2_setattr,
 #ifdef CONFIG_EXT2_FS_XATTR
 	.setxattr	= generic_setxattr,
@@ -35,7 +34,7 @@ const struct inode_operations ext2_symlink_inode_operations = {
  
 const struct inode_operations ext2_fast_symlink_inode_operations = {
 	.readlink	= generic_readlink,
-	.follow_link	= simple_follow_link,
+	.get_link	= simple_get_link,
 	.setattr	= ext2_setattr,
 #ifdef CONFIG_EXT2_FS_XATTR
 	.setxattr	= generic_setxattr,

fs/ext4/inode.c

@@ -4283,6 +4283,7 @@ struct inode *ext4_iget(struct super_block *sb, unsigned long ino)
 			inode->i_op = &ext4_symlink_inode_operations;
 			ext4_set_aops(inode);
 		}
+		inode_nohighmem(inode);
 	} else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode) ||
 	      S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) {
 		inode->i_op = &ext4_special_inode_operations;

fs/ext4/namei.c

@@ -3132,6 +3132,7 @@ static int ext4_symlink(struct inode *dir,
 	if ((disk_link.len > EXT4_N_BLOCKS * 4)) {
 		if (!encryption_required)
 			inode->i_op = &ext4_symlink_inode_operations;
+		inode_nohighmem(inode);
 		ext4_set_aops(inode);
 		/*
 		 * We cannot call page_symlink() with transaction started

fs/ext4/symlink.c

@@ -23,17 +23,21 @@
 #include "xattr.h"
 
 #ifdef CONFIG_EXT4_FS_ENCRYPTION
-static const char *ext4_encrypted_follow_link(struct dentry *dentry, void **cookie)
+static const char *ext4_encrypted_get_link(struct dentry *dentry,
+					   struct inode *inode,
+					   struct delayed_call *done)
 {
 	struct page *cpage = NULL;
 	char *caddr, *paddr = NULL;
 	struct ext4_str cstr, pstr;
-	struct inode *inode = d_inode(dentry);
 	struct ext4_encrypted_symlink_data *sd;
 	loff_t size = min_t(loff_t, i_size_read(inode), PAGE_SIZE - 1);
 	int res;
 	u32 plen, max_size = inode->i_sb->s_blocksize;
 
+	if (!dentry)
+		return ERR_PTR(-ECHILD);
+
 	res = ext4_get_encryption_info(inode);
 	if (res)
 		return ERR_PTR(res);
@@ -45,7 +49,7 @@ static const char *ext4_encrypted_follow_link(struct dentry *dentry, void **cook
 		cpage = read_mapping_page(inode->i_mapping, 0, NULL);
 		if (IS_ERR(cpage))
 			return ERR_CAST(cpage);
-		caddr = kmap(cpage);
+		caddr = page_address(cpage);
 		caddr[size] = 0;
 	}
 
@@ -75,24 +79,20 @@ static const char *ext4_encrypted_follow_link(struct dentry *dentry, void **cook
 	/* Null-terminate the name */
 	if (res <= plen)
 		paddr[res] = '\0';
-	if (cpage) {
-		kunmap(cpage);
+	if (cpage)
 		page_cache_release(cpage);
-	}
-	return *cookie = paddr;
+	set_delayed_call(done, kfree_link, paddr);
+	return paddr;
 errout:
-	if (cpage) {
-		kunmap(cpage);
+	if (cpage)
 		page_cache_release(cpage);
-	}
 	kfree(paddr);
 	return ERR_PTR(res);
 }
 
 const struct inode_operations ext4_encrypted_symlink_inode_operations = {
 	.readlink	= generic_readlink,
-	.follow_link    = ext4_encrypted_follow_link,
-	.put_link       = kfree_put_link,
+	.get_link	= ext4_encrypted_get_link,
 	.setattr	= ext4_setattr,
 	.setxattr	= generic_setxattr,
 	.getxattr	= generic_getxattr,
@@ -103,8 +103,7 @@ const struct inode_operations ext4_encrypted_symlink_inode_operations = {
 
 const struct inode_operations ext4_symlink_inode_operations = {
 	.readlink	= generic_readlink,
-	.follow_link	= page_follow_link_light,
-	.put_link	= page_put_link,
+	.get_link	= page_get_link,
 	.setattr	= ext4_setattr,
 	.setxattr	= generic_setxattr,
 	.getxattr	= generic_getxattr,
@@ -114,7 +113,7 @@ const struct inode_operations ext4_symlink_inode_operations = {
 
 const struct inode_operations ext4_fast_symlink_inode_operations = {
 	.readlink	= generic_readlink,
-	.follow_link    = simple_follow_link,
+	.get_link	= simple_get_link,
 	.setattr	= ext4_setattr,
 	.setxattr	= generic_setxattr,
 	.getxattr	= generic_getxattr,

fs/f2fs/inode.c

@@ -202,6 +202,7 @@ make_now:
 			inode->i_op = &f2fs_encrypted_symlink_inode_operations;
 		else
 			inode->i_op = &f2fs_symlink_inode_operations;
+		inode_nohighmem(inode);
 		inode->i_mapping->a_ops = &f2fs_dblock_aops;
 	} else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode) ||
 			S_ISFIFO(inode->i_mode) || S_ISSOCK(inode->i_mode)) {

fs/f2fs/namei.c

@@ -315,12 +315,15 @@ fail:
 	return err;
 }
 
-static const char *f2fs_follow_link(struct dentry *dentry, void **cookie)
+static const char *f2fs_get_link(struct dentry *dentry,
+				 struct inode *inode,
+				 struct delayed_call *done)
 {
-	const char *link = page_follow_link_light(dentry, cookie);
+	const char *link = page_get_link(dentry, inode, done);
 	if (!IS_ERR(link) && !*link) {
 		/* this is broken symlink case */
-		page_put_link(NULL, *cookie);
+		do_delayed_call(done);
+		clear_delayed_call(done);
 		link = ERR_PTR(-ENOENT);
 	}
 	return link;
@@ -351,6 +354,7 @@ static int f2fs_symlink(struct inode *dir, struct dentry *dentry,
 		inode->i_op = &f2fs_encrypted_symlink_inode_operations;
 	else
 		inode->i_op = &f2fs_symlink_inode_operations;
+	inode_nohighmem(inode);
 	inode->i_mapping->a_ops = &f2fs_dblock_aops;
 
 	f2fs_lock_op(sbi);
@@ -923,18 +927,22 @@ static int f2fs_rename2(struct inode *old_dir, struct dentry *old_dentry,
 }
 
 #ifdef CONFIG_F2FS_FS_ENCRYPTION
-static const char *f2fs_encrypted_follow_link(struct dentry *dentry, void **cookie)
+static const char *f2fs_encrypted_get_link(struct dentry *dentry,
+					   struct inode *inode,
+					   struct delayed_call *done)
 {
 	struct page *cpage = NULL;
 	char *caddr, *paddr = NULL;
 	struct f2fs_str cstr;
 	struct f2fs_str pstr = FSTR_INIT(NULL, 0);
-	struct inode *inode = d_inode(dentry);
 	struct f2fs_encrypted_symlink_data *sd;
 	loff_t size = min_t(loff_t, i_size_read(inode), PAGE_SIZE - 1);
 	u32 max_size = inode->i_sb->s_blocksize;
 	int res;
 
+	if (!dentry)
+		return ERR_PTR(-ECHILD);
+
 	res = f2fs_get_encryption_info(inode);
 	if (res)
 		return ERR_PTR(res);
@@ -942,7 +950,7 @@ static const char *f2fs_encrypted_follow_link(struct dentry *dentry, void **cook
 	cpage = read_mapping_page(inode->i_mapping, 0, NULL);
 	if (IS_ERR(cpage))
 		return ERR_CAST(cpage);
-	caddr = kmap(cpage);
+	caddr = page_address(cpage);
 	caddr[size] = 0;
 
 	/* Symlink is encrypted */
@@ -982,21 +990,19 @@ static const char *f2fs_encrypted_follow_link(struct dentry *dentry, void **cook
 	/* Null-terminate the name */
 	paddr[res] = '\0';
 
-	kunmap(cpage);
 	page_cache_release(cpage);
-	return *cookie = paddr;
+	set_delayed_call(done, kfree_link, paddr);
+	return paddr;
 errout:
 	kfree(cstr.name);
 	f2fs_fname_crypto_free_buffer(&pstr);
-	kunmap(cpage);
 	page_cache_release(cpage);
 	return ERR_PTR(res);
 }
 
 const struct inode_operations f2fs_encrypted_symlink_inode_operations = {
 	.readlink       = generic_readlink,
-	.follow_link    = f2fs_encrypted_follow_link,
-	.put_link       = kfree_put_link,
+	.get_link       = f2fs_encrypted_get_link,
 	.getattr	= f2fs_getattr,
 	.setattr	= f2fs_setattr,
 	.setxattr	= generic_setxattr,
@@ -1031,8 +1037,7 @@ const struct inode_operations f2fs_dir_inode_operations = {
 
 const struct inode_operations f2fs_symlink_inode_operations = {
 	.readlink       = generic_readlink,
-	.follow_link    = f2fs_follow_link,
-	.put_link       = page_put_link,
+	.get_link       = f2fs_get_link,
 	.getattr	= f2fs_getattr,
 	.setattr	= f2fs_setattr,
 #ifdef CONFIG_F2FS_FS_XATTR

fs/freevxfs/vxfs_inode.c

@@ -326,6 +326,7 @@ vxfs_iget(struct super_block *sbp, ino_t ino)
 	} else if (S_ISLNK(ip->i_mode)) {
 		if (!VXFS_ISIMMED(vip)) {
 			ip->i_op = &page_symlink_inode_operations;
+			inode_nohighmem(ip);
 			ip->i_mapping->a_ops = &vxfs_aops;
 		} else {
 			ip->i_op = &simple_symlink_inode_operations;

fs/fuse/dir.c

@@ -1365,15 +1365,19 @@ static int fuse_readdir(struct file *file, struct dir_context *ctx)
 	return err;
 }
 
-static const char *fuse_follow_link(struct dentry *dentry, void **cookie)
+static const char *fuse_get_link(struct dentry *dentry,
+				 struct inode *inode,
+				 struct delayed_call *done)
 {
-	struct inode *inode = d_inode(dentry);
 	struct fuse_conn *fc = get_fuse_conn(inode);
 	FUSE_ARGS(args);
 	char *link;
 	ssize_t ret;
 
-	link = (char *) __get_free_page(GFP_KERNEL);
+	if (!dentry)
+		return ERR_PTR(-ECHILD);
+
+	link = kmalloc(PAGE_SIZE, GFP_KERNEL);
 	if (!link)
 		return ERR_PTR(-ENOMEM);
 
@@ -1385,11 +1389,11 @@ static const char *fuse_follow_link(struct dentry *dentry, void **cookie)
 	args.out.args[0].value = link;
 	ret = fuse_simple_request(fc, &args);
 	if (ret < 0) {
-		free_page((unsigned long) link);
+		kfree(link);
 		link = ERR_PTR(ret);
 	} else {
 		link[ret] = '\0';
-		*cookie = link;
+		set_delayed_call(done, kfree_link, link);
 	}
 	fuse_invalidate_atime(inode);
 	return link;
@@ -1909,8 +1913,7 @@ static const struct inode_operations fuse_common_inode_operations = {
 
 static const struct inode_operations fuse_symlink_inode_operations = {
 	.setattr	= fuse_setattr,
-	.follow_link	= fuse_follow_link,
-	.put_link	= free_page_put_link,
+	.get_link	= fuse_get_link,
 	.readlink	= generic_readlink,
 	.getattr	= fuse_getattr,
 	.setxattr	= fuse_setxattr,

fs/gfs2/inode.c

@@ -1712,24 +1712,30 @@ static int gfs2_rename2(struct inode *odir, struct dentry *odentry,
 }
 
 /**
- * gfs2_follow_link - Follow a symbolic link
+ * gfs2_get_link - Follow a symbolic link
  * @dentry: The dentry of the link
- * @nd: Data that we pass to vfs_follow_link()
+ * @inode: The inode of the link
+ * @done: destructor for return value
  *
  * This can handle symlinks of any size.
  *
  * Returns: 0 on success or error code
  */
 
-static const char *gfs2_follow_link(struct dentry *dentry, void **cookie)
+static const char *gfs2_get_link(struct dentry *dentry,
+				 struct inode *inode,
+				 struct delayed_call *done)
 {
-	struct gfs2_inode *ip = GFS2_I(d_inode(dentry));
+	struct gfs2_inode *ip = GFS2_I(inode);
 	struct gfs2_holder i_gh;
 	struct buffer_head *dibh;
 	unsigned int size;
 	char *buf;
 	int error;
 
+	if (!dentry)
+		return ERR_PTR(-ECHILD);
+
 	gfs2_holder_init(ip->i_gl, LM_ST_SHARED, 0, &i_gh);
 	error = gfs2_glock_nq(&i_gh);
 	if (error) {
@@ -1759,7 +1765,7 @@ static const char *gfs2_follow_link(struct dentry *dentry, void **cookie)
 out:
 	gfs2_glock_dq_uninit(&i_gh);
 	if (!IS_ERR(buf))
-		*cookie = buf;
+		set_delayed_call(done, kfree_link, buf);
 	return buf;
 }
 
@@ -2132,8 +2138,7 @@ const struct inode_operations gfs2_dir_iops = {
 
 const struct inode_operations gfs2_symlink_iops = {
 	.readlink = generic_readlink,
-	.follow_link = gfs2_follow_link,
-	.put_link = kfree_put_link,
+	.get_link = gfs2_get_link,
 	.permission = gfs2_permission,
 	.setattr = gfs2_setattr,
 	.getattr = gfs2_getattr,

fs/hfsplus/inode.c

@@ -403,6 +403,7 @@ struct inode *hfsplus_new_inode(struct super_block *sb, umode_t mode)
 	} else if (S_ISLNK(inode->i_mode)) {
 		sbi->file_count++;
 		inode->i_op = &page_symlink_inode_operations;
+		inode_nohighmem(inode);
 		inode->i_mapping->a_ops = &hfsplus_aops;
 		hip->clump_blocks = 1;
 	} else
@@ -526,6 +527,7 @@ int hfsplus_cat_read_inode(struct inode *inode, struct hfs_find_data *fd)
 			inode->i_mapping->a_ops = &hfsplus_aops;
 		} else if (S_ISLNK(inode->i_mode)) {
 			inode->i_op = &page_symlink_inode_operations;
+			inode_nohighmem(inode);
 			inode->i_mapping->a_ops = &hfsplus_aops;
 		} else {
 			init_special_inode(inode, inode->i_mode,

fs/hostfs/hostfs_kern.c

@@ -892,9 +892,14 @@ static const struct inode_operations hostfs_dir_iops = {
 	.setattr	= hostfs_setattr,
 };
 
-static const char *hostfs_follow_link(struct dentry *dentry, void **cookie)
+static const char *hostfs_get_link(struct dentry *dentry,
+				   struct inode *inode,
+				   struct delayed_call *done)
 {
-	char *link = __getname();
+	char *link;
+	if (!dentry)
+		return ERR_PTR(-ECHILD);
+	link = kmalloc(PATH_MAX, GFP_KERNEL);
 	if (link) {
 		char *path = dentry_name(dentry);
 		int err = -ENOMEM;
@@ -905,25 +910,20 @@ static const char *hostfs_follow_link(struct dentry *dentry, void **cookie)
 			__putname(path);
 		}
 		if (err < 0) {
-			__putname(link);
+			kfree(link);
 			return ERR_PTR(err);
 		}
 	} else {
 		return ERR_PTR(-ENOMEM);
 	}
 
-	return *cookie = link;
-}
-
-static void hostfs_put_link(struct inode *unused, void *cookie)
-{
-	__putname(cookie);
+	set_delayed_call(done, kfree_link, link);
+	return link;
 }
 
 static const struct inode_operations hostfs_link_iops = {
 	.readlink	= generic_readlink,
-	.follow_link	= hostfs_follow_link,
-	.put_link	= hostfs_put_link,
+	.get_link	= hostfs_get_link,
 };
 
 static int hostfs_fill_sb_common(struct super_block *sb, void *d, int silent)

fs/hpfs/inode.c

@@ -77,6 +77,7 @@ void hpfs_read_inode(struct inode *i)
 			kfree(ea);
 			i->i_mode = S_IFLNK | 0777;
 			i->i_op = &page_symlink_inode_operations;
+			inode_nohighmem(i);
 			i->i_data.a_ops = &hpfs_symlink_aops;
 			set_nlink(i, 1);
 			i->i_size = ea_size;

fs/hpfs/namei.c

@@ -332,6 +332,7 @@ static int hpfs_symlink(struct inode *dir, struct dentry *dentry, const char *sy
 	result->i_blocks = 1;
 	set_nlink(result, 1);
 	result->i_size = strlen(symlink);
+	inode_nohighmem(result);
 	result->i_op = &page_symlink_inode_operations;
 	result->i_data.a_ops = &hpfs_symlink_aops;
 
@@ -500,7 +501,7 @@ out:
 
 static int hpfs_symlink_readpage(struct file *file, struct page *page)
 {
-	char *link = kmap(page);
+	char *link = page_address(page);
 	struct inode *i = page->mapping->host;
 	struct fnode *fnode;
 	struct buffer_head *bh;
@@ -516,14 +517,12 @@ static int hpfs_symlink_readpage(struct file *file, struct page *page)
 		goto fail;
 	hpfs_unlock(i->i_sb);
 	SetPageUptodate(page);
-	kunmap(page);
 	unlock_page(page);
 	return 0;
 
 fail:
 	hpfs_unlock(i->i_sb);
 	SetPageError(page);
-	kunmap(page);
 	unlock_page(page);
 	return err;
 }

fs/hugetlbfs/inode.c

@@ -760,6 +760,7 @@ static struct inode *hugetlbfs_get_inode(struct super_block *sb,
 			break;
 		case S_IFLNK:
 			inode->i_op = &page_symlink_inode_operations;
+			inode_nohighmem(inode);
 			break;
 		}
 		lockdep_annotate_inode_mutex_key(inode);

fs/inode.c

@@ -2028,3 +2028,9 @@ void inode_set_flags(struct inode *inode, unsigned int flags,
 				  new_flags) != old_flags));
 }
 EXPORT_SYMBOL(inode_set_flags);
+
+void inode_nohighmem(struct inode *inode)
+{
+	mapping_set_gfp_mask(inode->i_mapping, GFP_USER);
+}
+EXPORT_SYMBOL(inode_nohighmem);

fs/isofs/inode.c

@@ -1417,6 +1417,7 @@ static int isofs_read_inode(struct inode *inode, int relocated)
 		inode->i_fop = &isofs_dir_operations;
 	} else if (S_ISLNK(inode->i_mode)) {
 		inode->i_op = &page_symlink_inode_operations;
+		inode_nohighmem(inode);
 		inode->i_data.a_ops = &isofs_symlink_aops;
 	} else
 		/* XXX - parse_rock_ridge_inode() had already set i_rdev. */

fs/isofs/rock.c

@@ -687,7 +687,7 @@ static int rock_ridge_symlink_readpage(struct file *file, struct page *page)
 	struct inode *inode = page->mapping->host;
 	struct iso_inode_info *ei = ISOFS_I(inode);
 	struct isofs_sb_info *sbi = ISOFS_SB(inode->i_sb);
-	char *link = kmap(page);
+	char *link = page_address(page);
 	unsigned long bufsize = ISOFS_BUFFER_SIZE(inode);
 	struct buffer_head *bh;
 	char *rpnt = link;
@@ -774,7 +774,6 @@ repeat:
 	brelse(bh);
 	*rpnt = '\0';
 	SetPageUptodate(page);
-	kunmap(page);
 	unlock_page(page);
 	return 0;
 
@@ -791,7 +790,6 @@ fail:
 	brelse(bh);
 error:
 	SetPageError(page);
-	kunmap(page);
 	unlock_page(page);
 	return -EIO;
 }

fs/jffs2/symlink.c

@@ -14,7 +14,7 @@
 const struct inode_operations jffs2_symlink_inode_operations =
 {
 	.readlink =	generic_readlink,
-	.follow_link =	simple_follow_link,
+	.get_link =	simple_get_link,
 	.setattr =	jffs2_setattr,
 	.setxattr =	jffs2_setxattr,
 	.getxattr =	jffs2_getxattr,

fs/jfs/inode.c

@@ -60,6 +60,7 @@ struct inode *jfs_iget(struct super_block *sb, unsigned long ino)
 	} else if (S_ISLNK(inode->i_mode)) {
 		if (inode->i_size >= IDATASIZE) {
 			inode->i_op = &page_symlink_inode_operations;
+			inode_nohighmem(inode);
 			inode->i_mapping->a_ops = &jfs_aops;
 		} else {
 			inode->i_op = &jfs_fast_symlink_inode_operations;

fs/jfs/namei.c

@@ -983,6 +983,7 @@ static int jfs_symlink(struct inode *dip, struct dentry *dentry,
 		jfs_info("jfs_symlink: allocate extent ip:0x%p", ip);
 
 		ip->i_op = &jfs_symlink_inode_operations;
+		inode_nohighmem(ip);
 		ip->i_mapping->a_ops = &jfs_aops;
 
 		/*

fs/jfs/symlink.c

@@ -23,7 +23,7 @@
 
 const struct inode_operations jfs_fast_symlink_inode_operations = {
 	.readlink	= generic_readlink,
-	.follow_link	= simple_follow_link,
+	.get_link	= simple_get_link,
 	.setattr	= jfs_setattr,
 	.setxattr	= jfs_setxattr,
 	.getxattr	= jfs_getxattr,
@@ -33,8 +33,7 @@ const struct inode_operations jfs_fast_symlink_inode_operations = {
 
 const struct inode_operations jfs_symlink_inode_operations = {
 	.readlink	= generic_readlink,
-	.follow_link	= page_follow_link_light,
-	.put_link	= page_put_link,
+	.get_link	= page_get_link,
 	.setattr	= jfs_setattr,
 	.setxattr	= jfs_setxattr,
 	.getxattr	= jfs_getxattr,

fs/kernfs/symlink.c

@@ -112,18 +112,25 @@ static int kernfs_getlink(struct dentry *dentry, char *path)
 	return error;
 }
 
-static const char *kernfs_iop_follow_link(struct dentry *dentry, void **cookie)
+static const char *kernfs_iop_get_link(struct dentry *dentry,
+				       struct inode *inode,
+				       struct delayed_call *done)
 {
-	int error = -ENOMEM;
-	unsigned long page = get_zeroed_page(GFP_KERNEL);
-	if (!page)
+	char *body;
+	int error;
+
+	if (!dentry)
+		return ERR_PTR(-ECHILD);
+	body = kzalloc(PAGE_SIZE, GFP_KERNEL);
+	if (!body)
 		return ERR_PTR(-ENOMEM);
-	error = kernfs_getlink(dentry, (char *)page);
+	error = kernfs_getlink(dentry, body);
 	if (unlikely(error < 0)) {
-		free_page((unsigned long)page);
+		kfree(body);
 		return ERR_PTR(error);
 	}
-	return *cookie = (char *)page;
+	set_delayed_call(done, kfree_link, body);
+	return body;
 }
 
 const struct inode_operations kernfs_symlink_iops = {
@@ -132,8 +139,7 @@ const struct inode_operations kernfs_symlink_iops = {
 	.getxattr	= kernfs_iop_getxattr,
 	.listxattr	= kernfs_iop_listxattr,
 	.readlink	= generic_readlink,
-	.follow_link	= kernfs_iop_follow_link,
-	.put_link	= free_page_put_link,
+	.get_link	= kernfs_iop_get_link,
 	.setattr	= kernfs_iop_setattr,
 	.getattr	= kernfs_iop_getattr,
 	.permission	= kernfs_iop_permission,

fs/libfs.c

@@ -1019,17 +1019,12 @@ int noop_fsync(struct file *file, loff_t start, loff_t end, int datasync)
 }
 EXPORT_SYMBOL(noop_fsync);
 
-void kfree_put_link(struct inode *unused, void *cookie)
+/* Because kfree isn't assignment-compatible with void(void*) ;-/ */
+void kfree_link(void *p)
 {
-	kfree(cookie);
+	kfree(p);
 }
-EXPORT_SYMBOL(kfree_put_link);
-
-void free_page_put_link(struct inode *unused, void *cookie)
-{
-	free_page((unsigned long) cookie);
-}
-EXPORT_SYMBOL(free_page_put_link);
+EXPORT_SYMBOL(kfree_link);
 
 /*
  * nop .set_page_dirty method so that people can use .page_mkwrite on
@@ -1092,14 +1087,15 @@ simple_nosetlease(struct file *filp, long arg, struct file_lock **flp,
 }
 EXPORT_SYMBOL(simple_nosetlease);
 
-const char *simple_follow_link(struct dentry *dentry, void **cookie)
+const char *simple_get_link(struct dentry *dentry, struct inode *inode,
+			    struct delayed_call *done)
 {
-	return d_inode(dentry)->i_link;
+	return inode->i_link;
 }
-EXPORT_SYMBOL(simple_follow_link);
+EXPORT_SYMBOL(simple_get_link);
 
 const struct inode_operations simple_symlink_inode_operations = {
-	.follow_link = simple_follow_link,
+	.get_link = simple_get_link,
 	.readlink = generic_readlink
 };
 EXPORT_SYMBOL(simple_symlink_inode_operations);

fs/logfs/dir.c

@@ -528,7 +528,8 @@ static int logfs_symlink(struct inode *dir, struct dentry *dentry,
 	if (IS_ERR(inode))
 		return PTR_ERR(inode);
 
-	inode->i_op = &logfs_symlink_iops;
+	inode->i_op = &page_symlink_inode_operations;
+	inode_nohighmem(inode);
 	inode->i_mapping->a_ops = &logfs_reg_aops;
 
 	return __logfs_create(dir, dentry, inode, target, destlen);
@@ -776,12 +777,6 @@ fail:
 	return -EIO;
 }
 
-const struct inode_operations logfs_symlink_iops = {
-	.readlink	= generic_readlink,
-	.follow_link	= page_follow_link_light,
-	.put_link	= page_put_link,
-};
-
 const struct inode_operations logfs_dir_iops = {
 	.create		= logfs_create,
 	.link		= logfs_link,

fs/logfs/inode.c

@@ -64,7 +64,8 @@ static void logfs_inode_setops(struct inode *inode)
 		inode->i_mapping->a_ops = &logfs_reg_aops;
 		break;
 	case S_IFLNK:
-		inode->i_op = &logfs_symlink_iops;
+		inode->i_op = &page_symlink_inode_operations;
+		inode_nohighmem(inode);
 		inode->i_mapping->a_ops = &logfs_reg_aops;
 		break;
 	case S_IFSOCK:	/* fall through */

fs/logfs/logfs.h

@@ -495,7 +495,6 @@ static inline int logfs_get_sb_mtd(struct logfs_super *s, int mtdnr)
 #endif
 
 /* dir.c */
-extern const struct inode_operations logfs_symlink_iops;
 extern const struct inode_operations logfs_dir_iops;
 extern const struct file_operations logfs_dir_fops;
 int logfs_replay_journal(struct super_block *sb);

fs/minix/inode.c

@@ -435,8 +435,7 @@ static const struct address_space_operations minix_aops = {
 
 static const struct inode_operations minix_symlink_inode_operations = {
 	.readlink	= generic_readlink,
-	.follow_link	= page_follow_link_light,
-	.put_link	= page_put_link,
+	.get_link	= page_get_link,
 	.getattr	= minix_getattr,
 };
 
@@ -452,6 +451,7 @@ void minix_set_inode(struct inode *inode, dev_t rdev)
 		inode->i_mapping->a_ops = &minix_aops;
 	} else if (S_ISLNK(inode->i_mode)) {
 		inode->i_op = &minix_symlink_inode_operations;
+		inode_nohighmem(inode);
 		inode->i_mapping->a_ops = &minix_aops;
 	} else
 		init_special_inode(inode, inode->i_mode, rdev);

fs/namei.c

@@ -505,13 +505,13 @@ struct nameidata {
 	int		total_link_count;
 	struct saved {
 		struct path link;
-		void *cookie;
+		struct delayed_call done;
 		const char *name;
-		struct inode *inode;
 		unsigned seq;
 	} *stack, internal[EMBEDDED_LEVELS];
 	struct filename	*name;
 	struct nameidata *saved;
+	struct inode	*link_inode;
 	unsigned	root_seq;
 	int		dfd;
 };
@@ -592,11 +592,8 @@ static void drop_links(struct nameidata *nd)
 	int i = nd->depth;
 	while (i--) {
 		struct saved *last = nd->stack + i;
-		struct inode *inode = last->inode;
-		if (last->cookie && inode->i_op->put_link) {
-			inode->i_op->put_link(inode, last->cookie);
-			last->cookie = NULL;
-		}
+		do_delayed_call(&last->done);
+		clear_delayed_call(&last->done);
 	}
 }
 
@@ -842,7 +839,7 @@ static inline void path_to_nameidata(const struct path *path,
 }
 
 /*
- * Helper to directly jump to a known parsed path from ->follow_link,
+ * Helper to directly jump to a known parsed path from ->get_link,
  * caller must have taken a reference to path beforehand.
  */
 void nd_jump_link(struct path *path)
@@ -858,9 +855,7 @@ void nd_jump_link(struct path *path)
 static inline void put_link(struct nameidata *nd)
 {
 	struct saved *last = nd->stack + --nd->depth;
-	struct inode *inode = last->inode;
-	if (last->cookie && inode->i_op->put_link)
-		inode->i_op->put_link(inode, last->cookie);
+	do_delayed_call(&last->done);
 	if (!(nd->flags & LOOKUP_RCU))
 		path_put(&last->link);
 }
@@ -892,7 +887,7 @@ static inline int may_follow_link(struct nameidata *nd)
 		return 0;
 
 	/* Allowed if owner and follower match. */
-	inode = nd->stack[0].inode;
+	inode = nd->link_inode;
 	if (uid_eq(current_cred()->fsuid, inode->i_uid))
 		return 0;
 
@@ -983,7 +978,7 @@ const char *get_link(struct nameidata *nd)
 {
 	struct saved *last = nd->stack + nd->depth - 1;
 	struct dentry *dentry = last->link.dentry;
-	struct inode *inode = last->inode;
+	struct inode *inode = nd->link_inode;
 	int error;
 	const char *res;
 
@@ -1004,15 +999,21 @@ const char *get_link(struct nameidata *nd)
 	nd->last_type = LAST_BIND;
 	res = inode->i_link;
 	if (!res) {
+		const char * (*get)(struct dentry *, struct inode *,
+				struct delayed_call *);
+		get = inode->i_op->get_link;
 		if (nd->flags & LOOKUP_RCU) {
-			if (unlikely(unlazy_walk(nd, NULL, 0)))
-				return ERR_PTR(-ECHILD);
+			res = get(NULL, inode, &last->done);
+			if (res == ERR_PTR(-ECHILD)) {
+				if (unlikely(unlazy_walk(nd, NULL, 0)))
+					return ERR_PTR(-ECHILD);
+				res = get(dentry, inode, &last->done);
+			}
+		} else {
+			res = get(dentry, inode, &last->done);
 		}
-		res = inode->i_op->follow_link(dentry, &last->cookie);
-		if (IS_ERR_OR_NULL(res)) {
-			last->cookie = NULL;
+		if (IS_ERR_OR_NULL(res))
 			return res;
-		}
 	}
 	if (*res == '/') {
 		if (nd->flags & LOOKUP_RCU) {
@@ -1691,8 +1692,8 @@ static int pick_link(struct nameidata *nd, struct path *link,
 
 	last = nd->stack + nd->depth++;
 	last->link = *link;
-	last->cookie = NULL;
-	last->inode = inode;
+	clear_delayed_call(&last->done);
+	nd->link_inode = inode;
 	last->seq = seq;
 	return 1;
 }
@@ -4495,72 +4496,73 @@ EXPORT_SYMBOL(readlink_copy);
 
 /*
  * A helper for ->readlink().  This should be used *ONLY* for symlinks that
- * have ->follow_link() touching nd only in nd_set_link().  Using (or not
- * using) it for any given inode is up to filesystem.
+ * have ->get_link() not calling nd_jump_link().  Using (or not using) it
+ * for any given inode is up to filesystem.
  */
 int generic_readlink(struct dentry *dentry, char __user *buffer, int buflen)
 {
-	void *cookie;
+	DEFINE_DELAYED_CALL(done);
 	struct inode *inode = d_inode(dentry);
 	const char *link = inode->i_link;
 	int res;
 
 	if (!link) {
-		link = inode->i_op->follow_link(dentry, &cookie);
+		link = inode->i_op->get_link(dentry, inode, &done);
 		if (IS_ERR(link))
 			return PTR_ERR(link);
 	}
 	res = readlink_copy(buffer, buflen, link);
-	if (inode->i_op->put_link)
-		inode->i_op->put_link(inode, cookie);
+	do_delayed_call(&done);
 	return res;
 }
 EXPORT_SYMBOL(generic_readlink);
 
 /* get the link contents into pagecache */
-static char *page_getlink(struct dentry * dentry, struct page **ppage)
+const char *page_get_link(struct dentry *dentry, struct inode *inode,
+			  struct delayed_call *callback)
 {
 	char *kaddr;
 	struct page *page;
-	struct address_space *mapping = dentry->d_inode->i_mapping;
-	page = read_mapping_page(mapping, 0, NULL);
-	if (IS_ERR(page))
-		return (char*)page;
-	*ppage = page;
-	kaddr = kmap(page);
-	nd_terminate_link(kaddr, dentry->d_inode->i_size, PAGE_SIZE - 1);
+	struct address_space *mapping = inode->i_mapping;
+
+	if (!dentry) {
+		page = find_get_page(mapping, 0);
+		if (!page)
+			return ERR_PTR(-ECHILD);
+		if (!PageUptodate(page)) {
+			put_page(page);
+			return ERR_PTR(-ECHILD);
+		}
+	} else {
+		page = read_mapping_page(mapping, 0, NULL);
+		if (IS_ERR(page))
+			return (char*)page;
+	}
+	set_delayed_call(callback, page_put_link, page);
+	BUG_ON(mapping_gfp_mask(mapping) & __GFP_HIGHMEM);
+	kaddr = page_address(page);
+	nd_terminate_link(kaddr, inode->i_size, PAGE_SIZE - 1);
 	return kaddr;
 }
 
-int page_readlink(struct dentry *dentry, char __user *buffer, int buflen)
-{
-	struct page *page = NULL;
-	int res = readlink_copy(buffer, buflen, page_getlink(dentry, &page));
-	if (page) {
-		kunmap(page);
-		page_cache_release(page);
-	}
-	return res;
-}
-EXPORT_SYMBOL(page_readlink);
+EXPORT_SYMBOL(page_get_link);
 
-const char *page_follow_link_light(struct dentry *dentry, void **cookie)
+void page_put_link(void *arg)
 {
-	struct page *page = NULL;
-	char *res = page_getlink(dentry, &page);
-	if (!IS_ERR(res))
-		*cookie = page;
-	return res;
+	put_page(arg);
 }
-EXPORT_SYMBOL(page_follow_link_light);
+EXPORT_SYMBOL(page_put_link);
 
-void page_put_link(struct inode *unused, void *cookie)
+int page_readlink(struct dentry *dentry, char __user *buffer, int buflen)
 {
-	struct page *page = cookie;
-	kunmap(page);
-	page_cache_release(page);
+	DEFINE_DELAYED_CALL(done);
+	int res = readlink_copy(buffer, buflen,
+				page_get_link(dentry, d_inode(dentry),
+					      &done));
+	do_delayed_call(&done);
+	return res;
 }
-EXPORT_SYMBOL(page_put_link);
+EXPORT_SYMBOL(page_readlink);
 
 /*
  * The nofs argument instructs pagecache_write_begin to pass AOP_FLAG_NOFS
@@ -4571,7 +4573,6 @@ int __page_symlink(struct inode *inode, const char *symname, int len, int nofs)
 	struct page *page;
 	void *fsdata;
 	int err;
-	char *kaddr;
 	unsigned int flags = AOP_FLAG_UNINTERRUPTIBLE;
 	if (nofs)
 		flags |= AOP_FLAG_NOFS;
@@ -4582,9 +4583,7 @@ retry:
 	if (err)
 		goto fail;
 
-	kaddr = kmap_atomic(page);
-	memcpy(kaddr, symname, len-1);
-	kunmap_atomic(kaddr);
+	memcpy(page_address(page), symname, len-1);
 
 	err = pagecache_write_end(NULL, mapping, 0, len-1, len-1,
 							page, fsdata);
@@ -4609,7 +4608,6 @@ EXPORT_SYMBOL(page_symlink);
 
 const struct inode_operations page_symlink_inode_operations = {
 	.readlink	= generic_readlink,
-	.follow_link	= page_follow_link_light,
-	.put_link	= page_put_link,
+	.get_link	= page_get_link,
 };
 EXPORT_SYMBOL(page_symlink_inode_operations);

fs/ncpfs/inode.c

@@ -244,8 +244,7 @@ static void ncp_set_attr(struct inode *inode, struct ncp_entry_info *nwinfo)
 #if defined(CONFIG_NCPFS_EXTRAS) || defined(CONFIG_NCPFS_NFS_NS)
 static const struct inode_operations ncp_symlink_inode_operations = {
 	.readlink	= generic_readlink,
-	.follow_link	= page_follow_link_light,
-	.put_link	= page_put_link,
+	.get_link	= page_get_link,
 	.setattr	= ncp_notify_change,
 };
 #endif
@@ -283,6 +282,7 @@ ncp_iget(struct super_block *sb, struct ncp_entry_info *info)
 #if defined(CONFIG_NCPFS_EXTRAS) || defined(CONFIG_NCPFS_NFS_NS)
 		} else if (S_ISLNK(inode->i_mode)) {
 			inode->i_op = &ncp_symlink_inode_operations;
+			inode_nohighmem(inode);
 			inode->i_data.a_ops = &ncp_symlink_aops;
 #endif
 		} else {

fs/nfs/inode.c

@@ -408,9 +408,10 @@ nfs_fhget(struct super_block *sb, struct nfs_fh *fh, struct nfs_fattr *fattr, st
 				inode->i_fop = NULL;
 				inode->i_flags |= S_AUTOMOUNT;
 			}
-		} else if (S_ISLNK(inode->i_mode))
+		} else if (S_ISLNK(inode->i_mode)) {
 			inode->i_op = &nfs_symlink_inode_operations;
-		else
+			inode_nohighmem(inode);
+		} else
 			init_special_inode(inode, inode->i_mode, fattr->rdev);
 
 		memset(&inode->i_atime, 0, sizeof(inode->i_atime));
@@ -1086,6 +1087,27 @@ static bool nfs_mapping_need_revalidate_inode(struct inode *inode)
 		|| NFS_STALE(inode);
 }
 
+int nfs_revalidate_mapping_rcu(struct inode *inode)
+{
+	struct nfs_inode *nfsi = NFS_I(inode);
+	unsigned long *bitlock = &nfsi->flags;
+	int ret = 0;
+
+	if (IS_SWAPFILE(inode))
+		goto out;
+	if (nfs_mapping_need_revalidate_inode(inode)) {
+		ret = -ECHILD;
+		goto out;
+	}
+	spin_lock(&inode->i_lock);
+	if (test_bit(NFS_INO_INVALIDATING, bitlock) ||
+	    (nfsi->cache_validity & NFS_INO_INVALID_DATA))
+		ret = -ECHILD;
+	spin_unlock(&inode->i_lock);
+out:
+	return ret;
+}
+
 /**
  * __nfs_revalidate_mapping - Revalidate the pagecache
  * @inode - pointer to host inode

fs/nfs/symlink.c

@@ -42,21 +42,35 @@ error:
 	return -EIO;
 }
 
-static const char *nfs_follow_link(struct dentry *dentry, void **cookie)
+static const char *nfs_get_link(struct dentry *dentry,
+				struct inode *inode,
+				struct delayed_call *done)
 {
-	struct inode *inode = d_inode(dentry);
 	struct page *page;
 	void *err;
 
-	err = ERR_PTR(nfs_revalidate_mapping(inode, inode->i_mapping));
-	if (err)
-		return err;
-	page = read_cache_page(&inode->i_data, 0,
-				(filler_t *)nfs_symlink_filler, inode);
-	if (IS_ERR(page))
-		return ERR_CAST(page);
-	*cookie = page;
-	return kmap(page);
+	if (!dentry) {
+		err = ERR_PTR(nfs_revalidate_mapping_rcu(inode));
+		if (err)
+			return err;
+		page = find_get_page(inode->i_mapping, 0);
+		if (!page)
+			return ERR_PTR(-ECHILD);
+		if (!PageUptodate(page)) {
+			put_page(page);
+			return ERR_PTR(-ECHILD);
+		}
+	} else {
+		err = ERR_PTR(nfs_revalidate_mapping(inode, inode->i_mapping));
+		if (err)
+			return err;
+		page = read_cache_page(&inode->i_data, 0,
+					(filler_t *)nfs_symlink_filler, inode);
+		if (IS_ERR(page))
+			return ERR_CAST(page);
+	}
+	set_delayed_call(done, page_put_link, page);
+	return page_address(page);
 }
 
 /*
@@ -64,8 +78,7 @@ static const char *nfs_follow_link(struct dentry *dentry, void **cookie)
  */
 const struct inode_operations nfs_symlink_inode_operations = {
 	.readlink	= generic_readlink,
-	.follow_link	= nfs_follow_link,
-	.put_link	= page_put_link,
+	.get_link	= nfs_get_link,
 	.getattr	= nfs_getattr,
 	.setattr	= nfs_setattr,
 };

fs/nilfs2/inode.c

@@ -510,6 +510,7 @@ static int __nilfs_read_inode(struct super_block *sb,
 		inode->i_mapping->a_ops = &nilfs_aops;
 	} else if (S_ISLNK(inode->i_mode)) {
 		inode->i_op = &nilfs_symlink_inode_operations;
+		inode_nohighmem(inode);
 		inode->i_mapping->a_ops = &nilfs_aops;
 	} else {
 		inode->i_op = &nilfs_special_inode_operations;

fs/nilfs2/namei.c

@@ -161,6 +161,7 @@ static int nilfs_symlink(struct inode *dir, struct dentry *dentry,
 
 	/* slow symlink */
 	inode->i_op = &nilfs_symlink_inode_operations;
+	inode_nohighmem(inode);
 	inode->i_mapping->a_ops = &nilfs_aops;
 	err = page_symlink(inode, symname, l);
 	if (err)
@@ -568,8 +569,7 @@ const struct inode_operations nilfs_special_inode_operations = {
 
 const struct inode_operations nilfs_symlink_inode_operations = {
 	.readlink	= generic_readlink,
-	.follow_link	= page_follow_link_light,
-	.put_link	= page_put_link,
+	.get_link	= page_get_link,
 	.permission     = nilfs_permission,
 };
 

fs/ocfs2/inode.c

@@ -361,6 +361,7 @@ void ocfs2_populate_inode(struct inode *inode, struct ocfs2_dinode *fe,
 		    break;
 	    case S_IFLNK:
 		    inode->i_op = &ocfs2_symlink_inode_operations;
+		    inode_nohighmem(inode);
 		    i_size_write(inode, le64_to_cpu(fe->i_size));
 		    break;
 	    default:

fs/ocfs2/namei.c

@@ -1958,6 +1958,7 @@ static int ocfs2_symlink(struct inode *dir,
 	inode->i_rdev = 0;
 	newsize = l - 1;
 	inode->i_op = &ocfs2_symlink_inode_operations;
+	inode_nohighmem(inode);
 	if (l > ocfs2_fast_symlink_chars(sb)) {
 		u32 offset = 0;
 

fs/ocfs2/symlink.c

@@ -88,8 +88,7 @@ const struct address_space_operations ocfs2_fast_symlink_aops = {
 
 const struct inode_operations ocfs2_symlink_inode_operations = {
 	.readlink	= generic_readlink,
-	.follow_link	= page_follow_link_light,
-	.put_link	= page_put_link,
+	.get_link	= page_get_link,
 	.getattr	= ocfs2_getattr,
 	.setattr	= ocfs2_setattr,
 	.setxattr	= generic_setxattr,

fs/overlayfs/inode.c

@@ -131,57 +131,23 @@ out_dput:
 	return err;
 }
 
-
-struct ovl_link_data {
-	struct dentry *realdentry;
-	void *cookie;
-};
-
-static const char *ovl_follow_link(struct dentry *dentry, void **cookie)
+static const char *ovl_get_link(struct dentry *dentry,
+				struct inode *inode,
+				struct delayed_call *done)
 {
 	struct dentry *realdentry;
 	struct inode *realinode;
-	struct ovl_link_data *data = NULL;
-	const char *ret;
+
+	if (!dentry)
+		return ERR_PTR(-ECHILD);
 
 	realdentry = ovl_dentry_real(dentry);
 	realinode = realdentry->d_inode;
 
-	if (WARN_ON(!realinode->i_op->follow_link))
+	if (WARN_ON(!realinode->i_op->get_link))
 		return ERR_PTR(-EPERM);
 
-	if (realinode->i_op->put_link) {
-		data = kmalloc(sizeof(struct ovl_link_data), GFP_KERNEL);
-		if (!data)
-			return ERR_PTR(-ENOMEM);
-		data->realdentry = realdentry;
-	}
-
-	ret = realinode->i_op->follow_link(realdentry, cookie);
-	if (IS_ERR_OR_NULL(ret)) {
-		kfree(data);
-		return ret;
-	}
-
-	if (data)
-		data->cookie = *cookie;
-
-	*cookie = data;
-
-	return ret;
-}
-
-static void ovl_put_link(struct inode *unused, void *c)
-{
-	struct inode *realinode;
-	struct ovl_link_data *data = c;
-
-	if (!data)
-		return;
-
-	realinode = data->realdentry->d_inode;
-	realinode->i_op->put_link(realinode, data->cookie);
-	kfree(data);
+	return realinode->i_op->get_link(realdentry, realinode, done);
 }
 
 static int ovl_readlink(struct dentry *dentry, char __user *buf, int bufsiz)
@@ -378,8 +344,7 @@ static const struct inode_operations ovl_file_inode_operations = {
 
 static const struct inode_operations ovl_symlink_inode_operations = {
 	.setattr	= ovl_setattr,
-	.follow_link	= ovl_follow_link,
-	.put_link	= ovl_put_link,
+	.get_link	= ovl_get_link,
 	.readlink	= ovl_readlink,
 	.getattr	= ovl_getattr,
 	.setxattr	= ovl_setxattr,

fs/proc/base.c

@@ -1564,12 +1564,16 @@ static int proc_exe_link(struct dentry *dentry, struct path *exe_path)
 		return -ENOENT;
 }
 
-static const char *proc_pid_follow_link(struct dentry *dentry, void **cookie)
+static const char *proc_pid_get_link(struct dentry *dentry,
+				     struct inode *inode,
+				     struct delayed_call *done)
 {
-	struct inode *inode = d_inode(dentry);
 	struct path path;
 	int error = -EACCES;
 
+	if (!dentry)
+		return ERR_PTR(-ECHILD);
+
 	/* Are we allowed to snoop on the tasks file descriptors? */
 	if (!proc_fd_access_allowed(inode))
 		goto out;
@@ -1630,7 +1634,7 @@ out:
 
 const struct inode_operations proc_pid_link_inode_operations = {
 	.readlink	= proc_pid_readlink,
-	.follow_link	= proc_pid_follow_link,
+	.get_link	= proc_pid_get_link,
 	.setattr	= proc_setattr,
 };
 
@@ -1895,7 +1899,7 @@ static const struct dentry_operations tid_map_files_dentry_operations = {
 	.d_delete	= pid_delete_dentry,
 };
 
-static int proc_map_files_get_link(struct dentry *dentry, struct path *path)
+static int map_files_get_link(struct dentry *dentry, struct path *path)
 {
 	unsigned long vm_start, vm_end;
 	struct vm_area_struct *vma;
@@ -1945,20 +1949,22 @@ struct map_files_info {
  * path to the file in question.
  */
 static const char *
-proc_map_files_follow_link(struct dentry *dentry, void **cookie)
+proc_map_files_get_link(struct dentry *dentry,
+			struct inode *inode,
+		        struct delayed_call *done)
 {
 	if (!capable(CAP_SYS_ADMIN))
 		return ERR_PTR(-EPERM);
 
-	return proc_pid_follow_link(dentry, NULL);
+	return proc_pid_get_link(dentry, inode, done);
 }
 
 /*
- * Identical to proc_pid_link_inode_operations except for follow_link()
+ * Identical to proc_pid_link_inode_operations except for get_link()
  */
 static const struct inode_operations proc_map_files_link_inode_operations = {
 	.readlink	= proc_pid_readlink,
-	.follow_link	= proc_map_files_follow_link,
+	.get_link	= proc_map_files_get_link,
 	.setattr	= proc_setattr,
 };
 
@@ -1975,7 +1981,7 @@ proc_map_files_instantiate(struct inode *dir, struct dentry *dentry,
 		return -ENOENT;
 
 	ei = PROC_I(inode);
-	ei->op.proc_get_link = proc_map_files_get_link;
+	ei->op.proc_get_link = map_files_get_link;
 
 	inode->i_op = &proc_map_files_link_inode_operations;
 	inode->i_size = 64;

fs/proc/inode.c

@@ -393,24 +393,25 @@ static const struct file_operations proc_reg_file_ops_no_compat = {
 };
 #endif
 
-static const char *proc_follow_link(struct dentry *dentry, void **cookie)
+static void proc_put_link(void *p)
 {
-	struct proc_dir_entry *pde = PDE(d_inode(dentry));
-	if (unlikely(!use_pde(pde)))
-		return ERR_PTR(-EINVAL);
-	*cookie = pde;
-	return pde->data;
+	unuse_pde(p);
 }
 
-static void proc_put_link(struct inode *unused, void *p)
+static const char *proc_get_link(struct dentry *dentry,
+				 struct inode *inode,
+				 struct delayed_call *done)
 {
-	unuse_pde(p);
+	struct proc_dir_entry *pde = PDE(inode);
+	if (unlikely(!use_pde(pde)))
+		return ERR_PTR(-EINVAL);
+	set_delayed_call(done, proc_put_link, pde);
+	return pde->data;
 }
 
 const struct inode_operations proc_link_inode_operations = {
 	.readlink	= generic_readlink,
-	.follow_link	= proc_follow_link,
-	.put_link	= proc_put_link,
+	.get_link	= proc_get_link,
 };
 
 struct inode *proc_get_inode(struct super_block *sb, struct proc_dir_entry *de)

fs/proc/namespaces.c

@@ -30,14 +30,18 @@ static const struct proc_ns_operations *ns_entries[] = {
 	&mntns_operations,
 };
 
-static const char *proc_ns_follow_link(struct dentry *dentry, void **cookie)
+static const char *proc_ns_get_link(struct dentry *dentry,
+				    struct inode *inode,
+				    struct delayed_call *done)
 {
-	struct inode *inode = d_inode(dentry);
 	const struct proc_ns_operations *ns_ops = PROC_I(inode)->ns_ops;
 	struct task_struct *task;
 	struct path ns_path;
 	void *error = ERR_PTR(-EACCES);
 
+	if (!dentry)
+		return ERR_PTR(-ECHILD);
+
 	task = get_proc_task(inode);
 	if (!task)
 		return error;
@@ -74,7 +78,7 @@ static int proc_ns_readlink(struct dentry *dentry, char __user *buffer, int bufl
 
 static const struct inode_operations proc_ns_link_inode_operations = {
 	.readlink	= proc_ns_readlink,
-	.follow_link	= proc_ns_follow_link,
+	.get_link	= proc_ns_get_link,
 	.setattr	= proc_setattr,
 };
 

fs/proc/self.c

@@ -18,26 +18,28 @@ static int proc_self_readlink(struct dentry *dentry, char __user *buffer,
 	return readlink_copy(buffer, buflen, tmp);
 }
 
-static const char *proc_self_follow_link(struct dentry *dentry, void **cookie)
+static const char *proc_self_get_link(struct dentry *dentry,
+				      struct inode *inode,
+				      struct delayed_call *done)
 {
-	struct pid_namespace *ns = dentry->d_sb->s_fs_info;
+	struct pid_namespace *ns = inode->i_sb->s_fs_info;
 	pid_t tgid = task_tgid_nr_ns(current, ns);
 	char *name;
 
 	if (!tgid)
 		return ERR_PTR(-ENOENT);
 	/* 11 for max length of signed int in decimal + NULL term */
-	name = kmalloc(12, GFP_KERNEL);
-	if (!name)
-		return ERR_PTR(-ENOMEM);
+	name = kmalloc(12, dentry ? GFP_KERNEL : GFP_ATOMIC);
+	if (unlikely(!name))
+		return dentry ? ERR_PTR(-ENOMEM) : ERR_PTR(-ECHILD);
 	sprintf(name, "%d", tgid);
-	return *cookie = name;
+	set_delayed_call(done, kfree_link, name);
+	return name;
 }
 
 static const struct inode_operations proc_self_inode_operations = {
 	.readlink	= proc_self_readlink,
-	.follow_link	= proc_self_follow_link,
-	.put_link	= kfree_put_link,
+	.get_link	= proc_self_get_link,
 };
 
 static unsigned self_inum;

fs/proc/thread_self.c

@@ -19,26 +19,29 @@ static int proc_thread_self_readlink(struct dentry *dentry, char __user *buffer,
 	return readlink_copy(buffer, buflen, tmp);
 }
 
-static const char *proc_thread_self_follow_link(struct dentry *dentry, void **cookie)
+static const char *proc_thread_self_get_link(struct dentry *dentry,
+					     struct inode *inode,
+					     struct delayed_call *done)
 {
-	struct pid_namespace *ns = dentry->d_sb->s_fs_info;
+	struct pid_namespace *ns = inode->i_sb->s_fs_info;
 	pid_t tgid = task_tgid_nr_ns(current, ns);
 	pid_t pid = task_pid_nr_ns(current, ns);
 	char *name;
 
 	if (!pid)
 		return ERR_PTR(-ENOENT);
-	name = kmalloc(PROC_NUMBUF + 6 + PROC_NUMBUF, GFP_KERNEL);
-	if (!name)
-		return ERR_PTR(-ENOMEM);
+	name = kmalloc(PROC_NUMBUF + 6 + PROC_NUMBUF,
+				dentry ? GFP_KERNEL : GFP_ATOMIC);
+	if (unlikely(!name))
+		return dentry ? ERR_PTR(-ENOMEM) : ERR_PTR(-ECHILD);
 	sprintf(name, "%d/task/%d", tgid, pid);
-	return *cookie = name;
+	set_delayed_call(done, kfree_link, name);
+	return name;
 }
 
 static const struct inode_operations proc_thread_self_inode_operations = {
 	.readlink	= proc_thread_self_readlink,
-	.follow_link	= proc_thread_self_follow_link,
-	.put_link	= kfree_put_link,
+	.get_link	= proc_thread_self_get_link,
 };
 
 static unsigned thread_self_inum;

fs/qnx4/inode.c

@@ -316,6 +316,7 @@ struct inode *qnx4_iget(struct super_block *sb, unsigned long ino)
 		inode->i_fop = &qnx4_dir_operations;
 	} else if (S_ISLNK(inode->i_mode)) {
 		inode->i_op = &page_symlink_inode_operations;
+		inode_nohighmem(inode);
 		inode->i_mapping->a_ops = &qnx4_aops;
 		qnx4_i(inode)->mmu_private = inode->i_size;
 	} else {

fs/qnx6/inode.c

@@ -582,6 +582,7 @@ struct inode *qnx6_iget(struct super_block *sb, unsigned ino)
 		inode->i_mapping->a_ops = &qnx6_aops;
 	} else if (S_ISLNK(inode->i_mode)) {
 		inode->i_op = &page_symlink_inode_operations;
+		inode_nohighmem(inode);
 		inode->i_mapping->a_ops = &qnx6_aops;
 	} else
 		init_special_inode(inode, inode->i_mode, 0);

fs/ramfs/inode.c

@@ -79,6 +79,7 @@ struct inode *ramfs_get_inode(struct super_block *sb,
 			break;
 		case S_IFLNK:
 			inode->i_op = &page_symlink_inode_operations;
+			inode_nohighmem(inode);
 			break;
 		}
 	}

fs/reiserfs/inode.c

@@ -1361,6 +1361,7 @@ static void init_inode(struct inode *inode, struct treepath *path)
 		inode->i_fop = &reiserfs_dir_operations;
 	} else if (S_ISLNK(inode->i_mode)) {
 		inode->i_op = &reiserfs_symlink_inode_operations;
+		inode_nohighmem(inode);
 		inode->i_mapping->a_ops = &reiserfs_address_space_operations;
 	} else {
 		inode->i_blocks = 0;

fs/reiserfs/namei.c

@@ -1170,6 +1170,7 @@ static int reiserfs_symlink(struct inode *parent_dir,
 	reiserfs_update_inode_transaction(parent_dir);
 
 	inode->i_op = &reiserfs_symlink_inode_operations;
+	inode_nohighmem(inode);
 	inode->i_mapping->a_ops = &reiserfs_address_space_operations;
 
 	retval = reiserfs_add_entry(&th, parent_dir, dentry->d_name.name,
@@ -1664,8 +1665,7 @@ const struct inode_operations reiserfs_dir_inode_operations = {
  */
 const struct inode_operations reiserfs_symlink_inode_operations = {
 	.readlink = generic_readlink,
-	.follow_link = page_follow_link_light,
-	.put_link = page_put_link,
+	.get_link	= page_get_link,
 	.setattr = reiserfs_setattr,
 	.setxattr = reiserfs_setxattr,
 	.getxattr = reiserfs_getxattr,

fs/romfs/super.c

@@ -360,6 +360,7 @@ static struct inode *romfs_iget(struct super_block *sb, unsigned long pos)
 		break;
 	case ROMFH_SYM:
 		i->i_op = &page_symlink_inode_operations;
+		inode_nohighmem(i);
 		i->i_data.a_ops = &romfs_aops;
 		mode |= S_IRWXUGO;
 		break;

fs/squashfs/inode.c

@@ -41,6 +41,7 @@
 #include <linux/fs.h>
 #include <linux/vfs.h>
 #include <linux/xattr.h>
+#include <linux/pagemap.h>
 
 #include "squashfs_fs.h"
 #include "squashfs_fs_sb.h"
@@ -291,6 +292,7 @@ int squashfs_read_inode(struct inode *inode, long long ino)
 		set_nlink(inode, le32_to_cpu(sqsh_ino->nlink));
 		inode->i_size = le32_to_cpu(sqsh_ino->symlink_size);
 		inode->i_op = &squashfs_symlink_inode_ops;
+		inode_nohighmem(inode);
 		inode->i_data.a_ops = &squashfs_symlink_aops;
 		inode->i_mode |= S_IFLNK;
 		squashfs_i(inode)->start = block;

fs/squashfs/symlink.c

@@ -119,8 +119,7 @@ const struct address_space_operations squashfs_symlink_aops = {
 
 const struct inode_operations squashfs_symlink_inode_ops = {
 	.readlink = generic_readlink,
-	.follow_link = page_follow_link_light,
-	.put_link = page_put_link,
+	.get_link = page_get_link,
 	.getxattr = generic_getxattr,
 	.listxattr = squashfs_listxattr
 };

fs/sysv/inode.c

@@ -146,8 +146,7 @@ static inline void write3byte(struct sysv_sb_info *sbi,
 
 static const struct inode_operations sysv_symlink_inode_operations = {
 	.readlink	= generic_readlink,
-	.follow_link	= page_follow_link_light,
-	.put_link	= page_put_link,
+	.get_link	= page_get_link,
 	.getattr	= sysv_getattr,
 };
 
@@ -163,6 +162,7 @@ void sysv_set_inode(struct inode *inode, dev_t rdev)
 		inode->i_mapping->a_ops = &sysv_aops;
 	} else if (S_ISLNK(inode->i_mode)) {
 		inode->i_op = &sysv_symlink_inode_operations;
+		inode_nohighmem(inode);
 		inode->i_mapping->a_ops = &sysv_aops;
 	} else
 		init_special_inode(inode, inode->i_mode, rdev);

fs/ubifs/file.c

@@ -1608,7 +1608,7 @@ const struct inode_operations ubifs_file_inode_operations = {
 
 const struct inode_operations ubifs_symlink_inode_operations = {
 	.readlink    = generic_readlink,
-	.follow_link = simple_follow_link,
+	.get_link    = simple_get_link,
 	.setattr     = ubifs_setattr,
 	.getattr     = ubifs_getattr,
 	.setxattr    = ubifs_setxattr,

fs/udf/inode.c

@@ -1540,7 +1540,8 @@ reread:
 		break;
 	case ICBTAG_FILE_TYPE_SYMLINK:
 		inode->i_data.a_ops = &udf_symlink_aops;
-		inode->i_op = &udf_symlink_inode_operations;
+		inode->i_op = &page_symlink_inode_operations;
+		inode_nohighmem(inode);
 		inode->i_mode = S_IFLNK | S_IRWXUGO;
 		break;
 	case ICBTAG_FILE_TYPE_MAIN:

fs/udf/namei.c

@@ -921,7 +921,8 @@ static int udf_symlink(struct inode *dir, struct dentry *dentry,
 	}
 
 	inode->i_data.a_ops = &udf_symlink_aops;
-	inode->i_op = &udf_symlink_inode_operations;
+	inode->i_op = &page_symlink_inode_operations;
+	inode_nohighmem(inode);
 
 	if (iinfo->i_alloc_type != ICBTAG_FLAG_AD_IN_ICB) {
 		struct kernel_lb_addr eloc;
@@ -1344,8 +1345,3 @@ const struct inode_operations udf_dir_inode_operations = {
 	.rename				= udf_rename,
 	.tmpfile			= udf_tmpfile,
 };
-const struct inode_operations udf_symlink_inode_operations = {
-	.readlink	= generic_readlink,
-	.follow_link	= page_follow_link_light,
-	.put_link	= page_put_link,
-};

fs/udf/symlink.c

@@ -107,7 +107,7 @@ static int udf_symlink_filler(struct file *file, struct page *page)
 	struct buffer_head *bh = NULL;
 	unsigned char *symlink;
 	int err;
-	unsigned char *p = kmap(page);
+	unsigned char *p = page_address(page);
 	struct udf_inode_info *iinfo;
 	uint32_t pos;
 
@@ -141,7 +141,6 @@ static int udf_symlink_filler(struct file *file, struct page *page)
 
 	up_read(&iinfo->i_data_sem);
 	SetPageUptodate(page);
-	kunmap(page);
 	unlock_page(page);
 	return 0;
 
@@ -149,7 +148,6 @@ out_unlock_inode:
 	up_read(&iinfo->i_data_sem);
 	SetPageError(page);
 out_unmap:
-	kunmap(page);
 	unlock_page(page);
 	return err;
 }

fs/udf/udfdecl.h

@@ -85,7 +85,6 @@ extern const struct inode_operations udf_dir_inode_operations;
 extern const struct file_operations udf_dir_operations;
 extern const struct inode_operations udf_file_inode_operations;
 extern const struct file_operations udf_file_operations;
-extern const struct inode_operations udf_symlink_inode_operations;
 extern const struct address_space_operations udf_aops;
 extern const struct address_space_operations udf_adinicb_aops;
 extern const struct address_space_operations udf_symlink_aops;

fs/ufs/Makefile

@@ -5,5 +5,5 @@
 obj-$(CONFIG_UFS_FS) += ufs.o
 
 ufs-objs := balloc.o cylinder.o dir.o file.o ialloc.o inode.o \
-	    namei.o super.o symlink.o util.o
+	    namei.o super.o util.o
 ccflags-$(CONFIG_UFS_DEBUG)    += -DDEBUG

fs/ufs/inode.c

@@ -528,11 +528,12 @@ static void ufs_set_inode_ops(struct inode *inode)
 		inode->i_mapping->a_ops = &ufs_aops;
 	} else if (S_ISLNK(inode->i_mode)) {
 		if (!inode->i_blocks) {
-			inode->i_op = &ufs_fast_symlink_inode_operations;
 			inode->i_link = (char *)UFS_I(inode)->i_u1.i_symlink;
+			inode->i_op = &simple_symlink_inode_operations;
 		} else {
-			inode->i_op = &ufs_symlink_inode_operations;
 			inode->i_mapping->a_ops = &ufs_aops;
+			inode->i_op = &page_symlink_inode_operations;
+			inode_nohighmem(inode);
 		}
 	} else
 		init_special_inode(inode, inode->i_mode,

fs/ufs/namei.c

@@ -123,14 +123,15 @@ static int ufs_symlink (struct inode * dir, struct dentry * dentry,
 
 	if (l > UFS_SB(sb)->s_uspi->s_maxsymlinklen) {
 		/* slow symlink */
-		inode->i_op = &ufs_symlink_inode_operations;
+		inode->i_op = &page_symlink_inode_operations;
+		inode_nohighmem(inode);
 		inode->i_mapping->a_ops = &ufs_aops;
 		err = page_symlink(inode, symname, l);
 		if (err)
 			goto out_fail;
 	} else {
 		/* fast symlink */
-		inode->i_op = &ufs_fast_symlink_inode_operations;
+		inode->i_op = &simple_symlink_inode_operations;
 		inode->i_link = (char *)UFS_I(inode)->i_u1.i_symlink;
 		memcpy(inode->i_link, symname, l);
 		inode->i_size = l-1;

fs/ufs/symlink.c

@@ -1,42 +0,0 @@
-/*
- *  linux/fs/ufs/symlink.c
- *
- * Only fast symlinks left here - the rest is done by generic code. AV, 1999
- *
- * Copyright (C) 1998
- * Daniel Pirkl <daniel.pirkl@emai.cz>
- * Charles University, Faculty of Mathematics and Physics
- *
- *  from
- *
- *  linux/fs/ext2/symlink.c
- *
- * Copyright (C) 1992, 1993, 1994, 1995
- * Remy Card (card@masi.ibp.fr)
- * Laboratoire MASI - Institut Blaise Pascal
- * Universite Pierre et Marie Curie (Paris VI)
- *
- *  from
- *
- *  linux/fs/minix/symlink.c
- *
- *  Copyright (C) 1991, 1992  Linus Torvalds
- *
- *  ext2 symlink handling code
- */
-
-#include "ufs_fs.h"
-#include "ufs.h"
-
-const struct inode_operations ufs_fast_symlink_inode_operations = {
-	.readlink	= generic_readlink,
-	.follow_link	= simple_follow_link,
-	.setattr	= ufs_setattr,
-};
-
-const struct inode_operations ufs_symlink_inode_operations = {
-	.readlink	= generic_readlink,
-	.follow_link	= page_follow_link_light,
-	.put_link	= page_put_link,
-	.setattr	= ufs_setattr,
-};

fs/ufs/ufs.h

@@ -136,10 +136,6 @@ extern __printf(3, 4)
 void ufs_panic(struct super_block *, const char *, const char *, ...);
 void ufs_mark_sb_dirty(struct super_block *sb);
 
-/* symlink.c */
-extern const struct inode_operations ufs_fast_symlink_inode_operations;
-extern const struct inode_operations ufs_symlink_inode_operations;
-
 static inline struct ufs_sb_info *UFS_SB(struct super_block *sb)
 {
 	return sb->s_fs_info;

fs/xfs/xfs_iops.c

@@ -414,13 +414,17 @@ xfs_vn_rename(
  * uio is kmalloced for this reason...
  */
 STATIC const char *
-xfs_vn_follow_link(
+xfs_vn_get_link(
 	struct dentry		*dentry,
-	void			**cookie)
+	struct inode		*inode,
+	struct delayed_call	*done)
 {
 	char			*link;
 	int			error = -ENOMEM;
 
+	if (!dentry)
+		return ERR_PTR(-ECHILD);
+
 	link = kmalloc(MAXPATHLEN+1, GFP_KERNEL);
 	if (!link)
 		goto out_err;
@@ -429,7 +433,8 @@ xfs_vn_follow_link(
 	if (unlikely(error))
 		goto out_kfree;
 
-	return *cookie = link;
+	set_delayed_call(done, kfree_link, link);
+	return link;
 
  out_kfree:
 	kfree(link);
@@ -1172,8 +1177,7 @@ static const struct inode_operations xfs_dir_ci_inode_operations = {
 
 static const struct inode_operations xfs_symlink_inode_operations = {
 	.readlink		= generic_readlink,
-	.follow_link		= xfs_vn_follow_link,
-	.put_link		= kfree_put_link,
+	.get_link		= xfs_vn_get_link,
 	.getattr		= xfs_vn_getattr,
 	.setattr		= xfs_vn_setattr,
 	.setxattr		= generic_setxattr,

include/linux/delayed_call.h

@@ -0,0 +1,34 @@
+#ifndef _DELAYED_CALL_H
+#define _DELAYED_CALL_H
+
+/*
+ * Poor man's closures; I wish we could've done them sanely polymorphic,
+ * but...
+ */
+
+struct delayed_call {
+	void (*fn)(void *);
+	void *arg;
+};
+
+#define DEFINE_DELAYED_CALL(name) struct delayed_call name = {NULL, NULL}
+
+/* I really wish we had closures with sane typechecking... */
+static inline void set_delayed_call(struct delayed_call *call,
+		void (*fn)(void *), void *arg)
+{
+	call->fn = fn;
+	call->arg = arg;
+}
+
+static inline void do_delayed_call(struct delayed_call *call)
+{
+	if (call->fn)
+		call->fn(call->arg);
+}
+
+static inline void clear_delayed_call(struct delayed_call *call)
+{
+	call->fn = NULL;
+}
+#endif

include/linux/fs.h

@@ -31,6 +31,7 @@
 #include <linux/blk_types.h>
 #include <linux/workqueue.h>
 #include <linux/percpu-rwsem.h>
+#include <linux/delayed_call.h>
 
 #include <asm/byteorder.h>
 #include <uapi/linux/fs.h>
@@ -1633,12 +1634,11 @@ struct file_operations {
 
 struct inode_operations {
 	struct dentry * (*lookup) (struct inode *,struct dentry *, unsigned int);
-	const char * (*follow_link) (struct dentry *, void **);
+	const char * (*get_link) (struct dentry *, struct inode *, struct delayed_call *);
 	int (*permission) (struct inode *, int);
 	struct posix_acl * (*get_acl)(struct inode *, int);
 
 	int (*readlink) (struct dentry *, char __user *,int);
-	void (*put_link) (struct inode *, void *);
 
 	int (*create) (struct inode *,struct dentry *, umode_t, bool);
 	int (*link) (struct dentry *,struct inode *,struct dentry *);
@@ -2736,14 +2736,14 @@ extern const struct file_operations generic_ro_fops;
 
 extern int readlink_copy(char __user *, int, const char *);
 extern int page_readlink(struct dentry *, char __user *, int);
-extern const char *page_follow_link_light(struct dentry *, void **);
-extern void page_put_link(struct inode *, void *);
+extern const char *page_get_link(struct dentry *, struct inode *,
+				 struct delayed_call *);
+extern void page_put_link(void *);
 extern int __page_symlink(struct inode *inode, const char *symname, int len,
 		int nofs);
 extern int page_symlink(struct inode *inode, const char *symname, int len);
 extern const struct inode_operations page_symlink_inode_operations;
-extern void kfree_put_link(struct inode *, void *);
-extern void free_page_put_link(struct inode *, void *);
+extern void kfree_link(void *);
 extern int generic_readlink(struct dentry *, char __user *, int);
 extern void generic_fillattr(struct inode *, struct kstat *);
 int vfs_getattr_nosec(struct path *path, struct kstat *stat);
@@ -2754,7 +2754,8 @@ void __inode_sub_bytes(struct inode *inode, loff_t bytes);
 void inode_sub_bytes(struct inode *inode, loff_t bytes);
 loff_t inode_get_bytes(struct inode *inode);
 void inode_set_bytes(struct inode *inode, loff_t bytes);
-const char *simple_follow_link(struct dentry *, void **);
+const char *simple_get_link(struct dentry *, struct inode *,
+			    struct delayed_call *);
 extern const struct inode_operations simple_symlink_inode_operations;
 
 extern int iterate_dir(struct file *, struct dir_context *);
@@ -3023,5 +3024,6 @@ static inline bool dir_relax(struct inode *inode)
 }
 
 extern bool path_noexec(const struct path *path);
+extern void inode_nohighmem(struct inode *inode);
 
 #endif /* _LINUX_FS_H */

include/linux/nfs_fs.h

@@ -359,6 +359,7 @@ extern int nfs_revalidate_inode(struct nfs_server *server, struct inode *inode);
 extern int nfs_revalidate_inode_rcu(struct nfs_server *server, struct inode *inode);
 extern int __nfs_revalidate_inode(struct nfs_server *, struct inode *);
 extern int nfs_revalidate_mapping(struct inode *inode, struct address_space *mapping);
+extern int nfs_revalidate_mapping_rcu(struct inode *inode);
 extern int nfs_revalidate_mapping_protected(struct inode *inode, struct address_space *mapping);
 extern int nfs_setattr(struct dentry *, struct iattr *);
 extern void nfs_setattr_update_inode(struct inode *inode, struct iattr *attr, struct nfs_fattr *);

mm/shmem.c

@@ -2438,7 +2438,6 @@ static int shmem_symlink(struct inode *dir, struct dentry *dentry, const char *s
 	int len;
 	struct inode *inode;
 	struct page *page;
-	char *kaddr;
 	struct shmem_inode_info *info;
 
 	len = strlen(symname) + 1;
@@ -2477,9 +2476,8 @@ static int shmem_symlink(struct inode *dir, struct dentry *dentry, const char *s
 		}
 		inode->i_mapping->a_ops = &shmem_aops;
 		inode->i_op = &shmem_symlink_inode_operations;
-		kaddr = kmap_atomic(page);
-		memcpy(kaddr, symname, len);
-		kunmap_atomic(kaddr);
+		inode_nohighmem(inode);
+		memcpy(page_address(page), symname, len);
 		SetPageUptodate(page);
 		set_page_dirty(page);
 		unlock_page(page);
@@ -2492,23 +2490,34 @@ static int shmem_symlink(struct inode *dir, struct dentry *dentry, const char *s
 	return 0;
 }
 
-static const char *shmem_follow_link(struct dentry *dentry, void **cookie)
+static void shmem_put_link(void *arg)
 {
-	struct page *page = NULL;
-	int error = shmem_getpage(d_inode(dentry), 0, &page, SGP_READ, NULL);
-	if (error)
-		return ERR_PTR(error);
-	unlock_page(page);
-	*cookie = page;
-	return kmap(page);
+	mark_page_accessed(arg);
+	put_page(arg);
 }
 
-static void shmem_put_link(struct inode *unused, void *cookie)
+static const char *shmem_get_link(struct dentry *dentry,
+				  struct inode *inode,
+				  struct delayed_call *done)
 {
-	struct page *page = cookie;
-	kunmap(page);
-	mark_page_accessed(page);
-	page_cache_release(page);
+	struct page *page = NULL;
+	int error;
+	if (!dentry) {
+		page = find_get_page(inode->i_mapping, 0);
+		if (!page)
+			return ERR_PTR(-ECHILD);
+		if (!PageUptodate(page)) {
+			put_page(page);
+			return ERR_PTR(-ECHILD);
+		}
+	} else {
+		error = shmem_getpage(inode, 0, &page, SGP_READ, NULL);
+		if (error)
+			return ERR_PTR(error);
+		unlock_page(page);
+	}
+	set_delayed_call(done, shmem_put_link, page);
+	return page_address(page);
 }
 
 #ifdef CONFIG_TMPFS_XATTR
@@ -2653,7 +2662,7 @@ static ssize_t shmem_listxattr(struct dentry *dentry, char *buffer, size_t size)
 
 static const struct inode_operations shmem_short_symlink_operations = {
 	.readlink	= generic_readlink,
-	.follow_link	= simple_follow_link,
+	.get_link	= simple_get_link,
 #ifdef CONFIG_TMPFS_XATTR
 	.setxattr	= shmem_setxattr,
 	.getxattr	= shmem_getxattr,
@@ -2664,8 +2673,7 @@ static const struct inode_operations shmem_short_symlink_operations = {
 
 static const struct inode_operations shmem_symlink_inode_operations = {
 	.readlink	= generic_readlink,
-	.follow_link	= shmem_follow_link,
-	.put_link	= shmem_put_link,
+	.get_link	= shmem_get_link,
 #ifdef CONFIG_TMPFS_XATTR
 	.setxattr	= shmem_setxattr,
 	.getxattr	= shmem_getxattr,