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

87 files changed, 456 insertions, 417 deletions

diff --git a/fs/9p/vfs_inode.c b/fs/9p/vfs_inode.c
index 511078586fa1..c7cc7c30f0c8 100644
--- a/fs/9p/vfs_inode.c
+++ b/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,
 };
diff --git a/fs/9p/vfs_inode_dotl.c b/fs/9p/vfs_inode_dotl.c
index cb899af1babc..a34702c998f5 100644
--- a/fs/9p/vfs_inode_dotl.c
+++ b/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,
diff --git a/fs/affs/inode.c b/fs/affs/inode.c
index 17349500592d..0fdb0f5b2239 100644
--- a/fs/affs/inode.c
+++ b/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;
diff --git a/fs/affs/namei.c b/fs/affs/namei.c
index 181e05b46e72..00d3002a6780 100644
--- a/fs/affs/namei.c
+++ b/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);
diff --git a/fs/affs/symlink.c b/fs/affs/symlink.c
index ea5b69a18ba9..69b03dbb792f 100644
--- a/fs/affs/symlink.c
+++ b/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,
 };
diff --git a/fs/afs/inode.c b/fs/afs/inode.c
index e06f5a23352a..86cc7264c21c 100644
--- a/fs/afs/inode.c
+++ b/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");
diff --git a/fs/autofs4/symlink.c b/fs/autofs4/symlink.c
index da0c33481bc0..84e037d1d129 100644
--- a/fs/autofs4/symlink.c
+++ b/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
 };
diff --git a/fs/befs/linuxvfs.c b/fs/befs/linuxvfs.c
index 46aedacfa6a8..25250fa87086 100644
--- a/fs/befs/linuxvfs.c
+++ b/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;
 }
 
 /*
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index a70c5790f8f5..1a41a65fd2ff 100644
--- a/fs/btrfs/inode.c
+++ b/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,
diff --git a/fs/ceph/inode.c b/fs/ceph/inode.c
index 498dcfa2dcdb..da55eb8bcffa 100644
--- a/fs/ceph/inode.c
+++ b/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,
diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c
index cbc0f4bca0c0..90e4e2b398b6 100644
--- a/fs/cifs/cifsfs.c
+++ b/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,
diff --git a/fs/cifs/cifsfs.h b/fs/cifs/cifsfs.h
index c3cc1609025f..26a1187d4323 100644
--- a/fs/cifs/cifsfs.h
+++ b/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 *);
diff --git a/fs/cifs/link.c b/fs/cifs/link.c
index e3548f73bdea..062c2375549a 100644
--- a/fs/cifs/link.c
+++ b/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
diff --git a/fs/coda/cnode.c b/fs/coda/cnode.c
index 7740b1c871c1..1bfb7ba4e85e 100644
--- a/fs/coda/cnode.c
+++ b/fs/coda/cnode.c
@@ -8,6 +8,7 @@