Merge uncontroversial parts of branch 'readlink' of git://git.kernel.…

…org/pub/scm/linux/kernel/git/mszeredi/vfs

Pull partial readlink cleanups from Miklos Szeredi.

This is the uncontroversial part of the readlink cleanup patch-set that
simplifies the default readlink handling.

Miklos and Al are still discussing the rest of the series.

* git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs:
  vfs: make generic_readlink() static
  vfs: remove ".readlink = generic_readlink" assignments
  vfs: default to generic_readlink()
  vfs: replace calling i_op->readlink with vfs_readlink()
  proc/self: use generic_readlink
  ecryptfs: use vfs_get_link()
  bad_inode: add missing i_op initializers

Documentation/filesystems/porting

@@ -596,3 +596,7 @@ in your dentry operations instead.
 [mandatory]
 	->rename() has an added flags argument.  Any flags not handled by the
         filesystem should result in EINVAL being returned.
+--
+[recommended]
+	->readlink is optional for symlinks.  Don't set, unless filesystem needs
+	to fake something for readlink(2).

Documentation/filesystems/vfs.txt

@@ -451,9 +451,6 @@ otherwise noted.
 	exist; this is checked by the VFS.  Unlike plain rename,
 	source and target may be of different type.
 
-  readlink: called by the readlink(2) system call. Only required if
-	you want to support reading symbolic links
-
   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
@@ -468,6 +465,12 @@ otherwise noted.
 	argument.  If request can't be handled without leaving RCU mode,
 	have it return ERR_PTR(-ECHILD).
 
+  readlink: this is now just an override for use by readlink(2) for the
+	cases when ->get_link uses nd_jump_link() or object is not in
+	fact a symlink.  Normally filesystems should only implement
+	->get_link for symlinks and readlink(2) will automatically use
+	that.
+
   permission: called by the VFS to check for access rights on a POSIX-like
   	filesystem.
 

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

@@ -149,7 +149,6 @@ static const char *ll_get_link(struct dentry *dentry,
 }
 
 const struct inode_operations ll_fast_symlink_inode_operations = {
-	.readlink	= generic_readlink,
 	.setattr	= ll_setattr,
 	.get_link	= ll_get_link,
 	.getattr	= ll_getattr,

fs/9p/vfs_inode.c

@@ -1464,7 +1464,6 @@ static const struct inode_operations v9fs_file_inode_operations = {
 };
 
 static const struct inode_operations v9fs_symlink_inode_operations = {
-	.readlink = generic_readlink,
 	.get_link = v9fs_vfs_get_link,
 	.getattr = v9fs_vfs_getattr,
 	.setattr = v9fs_vfs_setattr,

fs/9p/vfs_inode_dotl.c

@@ -979,7 +979,6 @@ const struct inode_operations v9fs_file_inode_operations_dotl = {
 };
 
 const struct inode_operations v9fs_symlink_inode_operations_dotl = {
-	.readlink = generic_readlink,
 	.get_link = v9fs_vfs_get_link_dotl,
 	.getattr = v9fs_vfs_getattr_dotl,
 	.setattr = v9fs_vfs_setattr_dotl,

fs/affs/symlink.c

@@ -70,7 +70,6 @@ const struct address_space_operations affs_symlink_aops = {
 };
 
 const struct inode_operations affs_symlink_inode_operations = {
-	.readlink	= generic_readlink,
 	.get_link	= page_get_link,
 	.setattr	= affs_notify_change,
 };

fs/autofs4/symlink.c

@@ -25,6 +25,5 @@ static const char *autofs4_get_link(struct dentry *dentry,
 }
 
 const struct inode_operations autofs4_symlink_inode_operations = {
-	.readlink	= generic_readlink,
 	.get_link	= autofs4_get_link
 };

fs/bad_inode.c

@@ -106,6 +106,50 @@ static ssize_t bad_inode_listxattr(struct dentry *dentry, char *buffer,
 	return -EIO;
 }
 
+static const char *bad_inode_get_link(struct dentry *dentry,
+				      struct inode *inode,
+				      struct delayed_call *done)
+{
+	return ERR_PTR(-EIO);
+}
+
+static struct posix_acl *bad_inode_get_acl(struct inode *inode, int type)
+{
+	return ERR_PTR(-EIO);
+}
+
+static int bad_inode_fiemap(struct inode *inode,
+			    struct fiemap_extent_info *fieinfo, u64 start,
+			    u64 len)
+{
+	return -EIO;
+}
+
+static int bad_inode_update_time(struct inode *inode, struct timespec *time,
+				 int flags)
+{
+	return -EIO;
+}
+
+static int bad_inode_atomic_open(struct inode *inode, struct dentry *dentry,
+				 struct file *file, unsigned int open_flag,
+				 umode_t create_mode, int *opened)
+{
+	return -EIO;
+}
+
+static int bad_inode_tmpfile(struct inode *inode, struct dentry *dentry,
+			     umode_t mode)
+{
+	return -EIO;
+}
+
+static int bad_inode_set_acl(struct inode *inode, struct posix_acl *acl,
+			     int type)
+{
+	return -EIO;
+}
+
 static const struct inode_operations bad_inode_ops =
 {
 	.create		= bad_inode_create,
@@ -118,14 +162,17 @@ static const struct inode_operations bad_inode_ops =
 	.mknod		= bad_inode_mknod,
 	.rename		= bad_inode_rename2,
 	.readlink	= bad_inode_readlink,
-	/* follow_link must be no-op, otherwise unmounting this inode
-	   won't work */
-	/* put_link returns void */
-	/* truncate returns void */
 	.permission	= bad_inode_permission,
 	.getattr	= bad_inode_getattr,
 	.setattr	= bad_inode_setattr,
 	.listxattr	= bad_inode_listxattr,
+	.get_link	= bad_inode_get_link,
+	.get_acl	= bad_inode_get_acl,
+	.fiemap		= bad_inode_fiemap,
+	.update_time	= bad_inode_update_time,
+	.atomic_open	= bad_inode_atomic_open,
+	.tmpfile	= bad_inode_tmpfile,
+	.set_acl	= bad_inode_set_acl,
 };
 
 

fs/btrfs/inode.c

@@ -10653,7 +10653,6 @@ static const struct inode_operations btrfs_special_inode_operations = {
 	.update_time	= btrfs_update_time,
 };
 static const struct inode_operations btrfs_symlink_inode_operations = {
-	.readlink	= generic_readlink,
 	.get_link	= page_get_link,
 	.getattr	= btrfs_getattr,
 	.setattr	= btrfs_setattr,

fs/ceph/inode.c

@@ -1869,7 +1869,6 @@ void __ceph_do_pending_vmtruncate(struct inode *inode)
  * symlinks
  */
 static const struct inode_operations ceph_symlink_iops = {
-	.readlink = generic_readlink,
 	.get_link = simple_get_link,
 	.setattr = ceph_setattr,
 	.getattr = ceph_getattr,

fs/cifs/cifsfs.c

@@ -914,7 +914,6 @@ const struct inode_operations cifs_file_inode_ops = {
 };
 
 const struct inode_operations cifs_symlink_inode_ops = {
-	.readlink = generic_readlink,
 	.get_link = cifs_get_link,
 	.permission = cifs_permission,
 	.listxattr = cifs_listxattr,

fs/coda/cnode.c

@@ -17,7 +17,6 @@ static inline int coda_fideq(struct CodaFid *fid1, struct CodaFid *fid2)
 }
 
 static const struct inode_operations coda_symlink_inode_operations = {
-	.readlink	= generic_readlink,
 	.get_link	= page_get_link,
 	.setattr	= coda_setattr,
 };

fs/configfs/symlink.c

@@ -305,7 +305,6 @@ static const char *configfs_get_link(struct dentry *dentry,
 
 const struct inode_operations configfs_symlink_inode_operations = {
 	.get_link = configfs_get_link,
-	.readlink = generic_readlink,
 	.setattr = configfs_setattr,
 };
 

fs/ecryptfs/inode.c

@@ -631,28 +631,23 @@ ecryptfs_rename(struct inode *old_dir, struct dentry *old_dentry,
 
 static char *ecryptfs_readlink_lower(struct dentry *dentry, size_t *bufsiz)
 {
+	DEFINE_DELAYED_CALL(done);
 	struct dentry *lower_dentry = ecryptfs_dentry_to_lower(dentry);
-	char *lower_buf;
+	const char *link;
 	char *buf;
-	mm_segment_t old_fs;
 	int rc;
 
-	lower_buf = kmalloc(PATH_MAX, GFP_KERNEL);
-	if (!lower_buf)
-		return ERR_PTR(-ENOMEM);
-	old_fs = get_fs();
-	set_fs(get_ds());
-	rc = d_inode(lower_dentry)->i_op->readlink(lower_dentry,
-						   (char __user *)lower_buf,
-						   PATH_MAX);
-	set_fs(old_fs);
-	if (rc < 0)
-		goto out;
+	link = vfs_get_link(lower_dentry, &done);
+	if (IS_ERR(link))
+		return ERR_CAST(link);
+
 	rc = ecryptfs_decode_and_decrypt_filename(&buf, bufsiz, dentry->d_sb,
-						  lower_buf, rc);
-out:
-	kfree(lower_buf);
-	return rc ? ERR_PTR(rc) : buf;
+						  link, strlen(link));
+	do_delayed_call(&done);
+	if (rc)
+		return ERR_PTR(rc);
+
+	return buf;
 }
 
 static const char *ecryptfs_get_link(struct dentry *dentry,
@@ -1089,7 +1084,6 @@ static int ecryptfs_removexattr(struct dentry *dentry, struct inode *inode,
 }
 
 const struct inode_operations ecryptfs_symlink_iops = {
-	.readlink = generic_readlink,
 	.get_link = ecryptfs_get_link,
 	.permission = ecryptfs_permission,
 	.setattr = ecryptfs_setattr,

fs/ext2/symlink.c

@@ -21,7 +21,6 @@
 #include "xattr.h"
 
 const struct inode_operations ext2_symlink_inode_operations = {
-	.readlink	= generic_readlink,
 	.get_link	= page_get_link,
 	.setattr	= ext2_setattr,
 #ifdef CONFIG_EXT2_FS_XATTR
@@ -30,7 +29,6 @@ const struct inode_operations ext2_symlink_inode_operations = {
 };
 
 const struct inode_operations ext2_fast_symlink_inode_operations = {
-	.readlink	= generic_readlink,
 	.get_link	= simple_get_link,
 	.setattr	= ext2_setattr,
 #ifdef CONFIG_EXT2_FS_XATTR

fs/ext4/symlink.c

@@ -83,21 +83,18 @@ static const char *ext4_encrypted_get_link(struct dentry *dentry,
 }
 
 const struct inode_operations ext4_encrypted_symlink_inode_operations = {
-	.readlink	= generic_readlink,
 	.get_link	= ext4_encrypted_get_link,
 	.setattr	= ext4_setattr,
 	.listxattr	= ext4_listxattr,
 };
 
 const struct inode_operations ext4_symlink_inode_operations = {
-	.readlink	= generic_readlink,
 	.get_link	= page_get_link,
 	.setattr	= ext4_setattr,
 	.listxattr	= ext4_listxattr,
 };
 
 const struct inode_operations ext4_fast_symlink_inode_operations = {
-	.readlink	= generic_readlink,
 	.get_link	= simple_get_link,
 	.setattr	= ext4_setattr,
 	.listxattr	= ext4_listxattr,

fs/f2fs/namei.c

@@ -1075,7 +1075,6 @@ static const char *f2fs_encrypted_get_link(struct dentry *dentry,
 }
 
 const struct inode_operations f2fs_encrypted_symlink_inode_operations = {
-	.readlink       = generic_readlink,
 	.get_link       = f2fs_encrypted_get_link,
 	.getattr	= f2fs_getattr,
 	.setattr	= f2fs_setattr,
@@ -1105,7 +1104,6 @@ const struct inode_operations f2fs_dir_inode_operations = {
 };
 
 const struct inode_operations f2fs_symlink_inode_operations = {
-	.readlink       = generic_readlink,
 	.get_link       = f2fs_get_link,
 	.getattr	= f2fs_getattr,
 	.setattr	= f2fs_setattr,

fs/fuse/dir.c

@@ -1831,7 +1831,6 @@ static const struct inode_operations fuse_common_inode_operations = {
 static const struct inode_operations fuse_symlink_inode_operations = {
 	.setattr	= fuse_setattr,
 	.get_link	= fuse_get_link,
-	.readlink	= generic_readlink,
 	.getattr	= fuse_getattr,
 	.listxattr	= fuse_listxattr,
 };

fs/gfs2/inode.c

@@ -2067,7 +2067,6 @@ const struct inode_operations gfs2_dir_iops = {
 };
 
 const struct inode_operations gfs2_symlink_iops = {
-	.readlink = generic_readlink,
 	.get_link = gfs2_get_link,
 	.permission = gfs2_permission,
 	.setattr = gfs2_setattr,

fs/hostfs/hostfs_kern.c

@@ -920,7 +920,6 @@ static const char *hostfs_get_link(struct dentry *dentry,
 }
 
 static const struct inode_operations hostfs_link_iops = {
-	.readlink	= generic_readlink,
 	.get_link	= hostfs_get_link,
 };
 

fs/jffs2/symlink.c

@@ -13,7 +13,6 @@
 
 const struct inode_operations jffs2_symlink_inode_operations =
 {
-	.readlink =	generic_readlink,
 	.get_link =	simple_get_link,
 	.setattr =	jffs2_setattr,
 	.listxattr =	jffs2_listxattr,

fs/jfs/symlink.c

@@ -22,14 +22,12 @@
 #include "jfs_xattr.h"
 
 const struct inode_operations jfs_fast_symlink_inode_operations = {
-	.readlink	= generic_readlink,
 	.get_link	= simple_get_link,
 	.setattr	= jfs_setattr,
 	.listxattr	= jfs_listxattr,
 };
 
 const struct inode_operations jfs_symlink_inode_operations = {
-	.readlink	= generic_readlink,
 	.get_link	= page_get_link,
 	.setattr	= jfs_setattr,
 	.listxattr	= jfs_listxattr,

fs/kernfs/symlink.c

@@ -135,7 +135,6 @@ static const char *kernfs_iop_get_link(struct dentry *dentry,
 
 const struct inode_operations kernfs_symlink_iops = {
 	.listxattr	= kernfs_iop_listxattr,
-	.readlink	= generic_readlink,
 	.get_link	= kernfs_iop_get_link,
 	.setattr	= kernfs_iop_setattr,
 	.getattr	= kernfs_iop_getattr,

fs/libfs.c

@@ -1131,7 +1131,6 @@ EXPORT_SYMBOL(simple_get_link);
 
 const struct inode_operations simple_symlink_inode_operations = {
 	.get_link = simple_get_link,
-	.readlink = generic_readlink
 };
 EXPORT_SYMBOL(simple_symlink_inode_operations);
 

fs/minix/inode.c

@@ -434,7 +434,6 @@ static const struct address_space_operations minix_aops = {
 };
 
 static const struct inode_operations minix_symlink_inode_operations = {
-	.readlink	= generic_readlink,
 	.get_link	= page_get_link,
 	.getattr	= minix_getattr,
 };