Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel…

…/git/viro/vfs-2.6

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6:
  [patch 7/7] vfs: mountinfo: show dominating group id
  [patch 6/7] vfs: mountinfo: add /proc/<pid>/mountinfo
  [patch 5/7] vfs: mountinfo: allow using process root
  [patch 4/7] vfs: mountinfo: add mount peer group ID
  [patch 3/7] vfs: mountinfo: add mount ID
  [patch 2/7] vfs: mountinfo: add seq_file_root()
  [patch 1/7] vfs: mountinfo: add dentry_path()
  [PATCH] remove unused label in xattr.c (noise from ro-bind)

Documentation/filesystems/proc.txt

@@ -43,6 +43,7 @@ Table of Contents
   2.13	/proc/<pid>/oom_score - Display current oom-killer score
   2.14	/proc/<pid>/io - Display the IO accounting fields
   2.15	/proc/<pid>/coredump_filter - Core dump filtering settings
+  2.16	/proc/<pid>/mountinfo - Information about mounts
 
 ------------------------------------------------------------------------------
 Preface
@@ -2348,4 +2349,41 @@ For example:
   $ echo 0x7 > /proc/self/coredump_filter
   $ ./some_program
 
+2.16	/proc/<pid>/mountinfo - Information about mounts
+--------------------------------------------------------
+
+This file contains lines of the form:
+
+36 35 98:0 /mnt1 /mnt2 rw,noatime master:1 - ext3 /dev/root rw,errors=continue
+(1)(2)(3)   (4)   (5)      (6)      (7)   (8) (9)   (10)         (11)
+
+(1) mount ID:  unique identifier of the mount (may be reused after umount)
+(2) parent ID:  ID of parent (or of self for the top of the mount tree)
+(3) major:minor:  value of st_dev for files on filesystem
+(4) root:  root of the mount within the filesystem
+(5) mount point:  mount point relative to the process's root
+(6) mount options:  per mount options
+(7) optional fields:  zero or more fields of the form "tag[:value]"
+(8) separator:  marks the end of the optional fields
+(9) filesystem type:  name of filesystem of the form "type[.subtype]"
+(10) mount source:  filesystem specific information or "none"
+(11) super options:  per super block options
+
+Parsers should ignore all unrecognised optional fields.  Currently the
+possible optional fields are:
+
+shared:X  mount is shared in peer group X
+master:X  mount is slave to peer group X
+propagate_from:X  mount is slave and receives propagation from peer group X (*)
+unbindable  mount is unbindable
+
+(*) X is the closest dominant peer group under the process's root.  If
+X is the immediate master of the mount, or if there's no dominant peer
+group under the same root, then only the "master:X" field is present
+and not the "propagate_from:X" field.
+
+For more information on mount propagation see:
+
+  Documentation/filesystems/sharedsubtree.txt
+
 ------------------------------------------------------------------------------

fs/dcache.c

@@ -1746,12 +1746,21 @@ struct dentry *d_materialise_unique(struct dentry *dentry, struct inode *inode)
 	goto shouldnt_be_hashed;
 }
 
+static int prepend(char **buffer, int *buflen, const char *str,
+			  int namelen)
+{
+	*buflen -= namelen;
+	if (*buflen < 0)
+		return -ENAMETOOLONG;
+	*buffer -= namelen;
+	memcpy(*buffer, str, namelen);
+	return 0;
+}
+
 /**
  * d_path - return the path of a dentry
- * @dentry: dentry to report
- * @vfsmnt: vfsmnt to which the dentry belongs
- * @root: root dentry
- * @rootmnt: vfsmnt to which the root dentry belongs
+ * @path: the dentry/vfsmount to report
+ * @root: root vfsmnt/dentry (may be modified by this function)
  * @buffer: buffer to return value in
  * @buflen: buffer length
  *
@@ -1761,23 +1770,22 @@ struct dentry *d_materialise_unique(struct dentry *dentry, struct inode *inode)
  * Returns the buffer or an error code if the path was too long.
  *
  * "buflen" should be positive. Caller holds the dcache_lock.
+ *
+ * If path is not reachable from the supplied root, then the value of
+ * root is changed (without modifying refcounts).
  */
-static char *__d_path(struct dentry *dentry, struct vfsmount *vfsmnt,
-		       struct path *root, char *buffer, int buflen)
+char *__d_path(const struct path *path, struct path *root,
+	       char *buffer, int buflen)
 {
+	struct dentry *dentry = path->dentry;
+	struct vfsmount *vfsmnt = path->mnt;
 	char * end = buffer+buflen;
 	char * retval;
-	int namelen;
-
-	*--end = '\0';
-	buflen--;
-	if (!IS_ROOT(dentry) && d_unhashed(dentry)) {
-		buflen -= 10;
-		end -= 10;
-		if (buflen < 0)
+
+	prepend(&end, &buflen, "\0", 1);
+	if (!IS_ROOT(dentry) && d_unhashed(dentry) &&
+		(prepend(&end, &buflen, " (deleted)", 10) != 0))
 			goto Elong;
-		memcpy(end, " (deleted)", 10);
-	}
 
 	if (buflen < 1)
 		goto Elong;
@@ -1804,26 +1812,23 @@ static char *__d_path(struct dentry *dentry, struct vfsmount *vfsmnt,
 		}
 		parent = dentry->d_parent;
 		prefetch(parent);
-		namelen = dentry->d_name.len;
-		buflen -= namelen + 1;
-		if (buflen < 0)
+		if ((prepend(&end, &buflen, dentry->d_name.name,
+				dentry->d_name.len) != 0) ||
+		    (prepend(&end, &buflen, "/", 1) != 0))
 			goto Elong;
-		end -= namelen;
-		memcpy(end, dentry->d_name.name, namelen);
-		*--end = '/';
 		retval = end;
 		dentry = parent;
 	}
 
 	return retval;
 
 global_root:
-	namelen = dentry->d_name.len;
-	buflen -= namelen;
-	if (buflen < 0)
+	retval += 1;	/* hit the slash */
+	if (prepend(&retval, &buflen, dentry->d_name.name,
+		    dentry->d_name.len) != 0)
 		goto Elong;
-	retval -= namelen-1;	/* hit the slash */
-	memcpy(retval, dentry->d_name.name, namelen);
+	root->mnt = vfsmnt;
+	root->dentry = dentry;
 	return retval;
 Elong:
 	return ERR_PTR(-ENAMETOOLONG);
@@ -1846,6 +1851,7 @@ char *d_path(struct path *path, char *buf, int buflen)
 {
 	char *res;
 	struct path root;
+	struct path tmp;
 
 	/*
 	 * We have various synthetic filesystems that never get mounted.  On
@@ -1859,10 +1865,11 @@ char *d_path(struct path *path, char *buf, int buflen)
 
 	read_lock(&current->fs->lock);
 	root = current->fs->root;
-	path_get(&current->fs->root);
+	path_get(&root);
 	read_unlock(&current->fs->lock);
 	spin_lock(&dcache_lock);
-	res = __d_path(path->dentry, path->mnt, &root, buf, buflen);
+	tmp = root;
+	res = __d_path(path, &tmp, buf, buflen);
 	spin_unlock(&dcache_lock);
 	path_put(&root);
 	return res;
@@ -1889,6 +1896,48 @@ char *dynamic_dname(struct dentry *dentry, char *buffer, int buflen,
 	return memcpy(buffer, temp, sz);
 }
 
+/*
+ * Write full pathname from the root of the filesystem into the buffer.
+ */
+char *dentry_path(struct dentry *dentry, char *buf, int buflen)
+{
+	char *end = buf + buflen;
+	char *retval;
+
+	spin_lock(&dcache_lock);
+	prepend(&end, &buflen, "\0", 1);
+	if (!IS_ROOT(dentry) && d_unhashed(dentry) &&
+		(prepend(&end, &buflen, "//deleted", 9) != 0))
+			goto Elong;
+	if (buflen < 1)
+		goto Elong;
+	/* Get '/' right */
+	retval = end-1;
+	*retval = '/';
+
+	for (;;) {
+		struct dentry *parent;
+		if (IS_ROOT(dentry))
+			break;
+
+		parent = dentry->d_parent;
+		prefetch(parent);
+
+		if ((prepend(&end, &buflen, dentry->d_name.name,
+				dentry->d_name.len) != 0) ||
+		    (prepend(&end, &buflen, "/", 1) != 0))
+			goto Elong;
+
+		retval = end;
+		dentry = parent;
+	}
+	spin_unlock(&dcache_lock);
+	return retval;
+Elong:
+	spin_unlock(&dcache_lock);
+	return ERR_PTR(-ENAMETOOLONG);
+}
+
 /*
  * NOTE! The user-level library version returns a
  * character pointer. The kernel system call just
@@ -1918,19 +1967,20 @@ asmlinkage long sys_getcwd(char __user *buf, unsigned long size)
 
 	read_lock(&current->fs->lock);
 	pwd = current->fs->pwd;
-	path_get(&current->fs->pwd);
+	path_get(&pwd);
 	root = current->fs->root;
-	path_get(&current->fs->root);
+	path_get(&root);
 	read_unlock(&current->fs->lock);
 
 	error = -ENOENT;
 	/* Has the current directory has been unlinked? */
 	spin_lock(&dcache_lock);
 	if (pwd.dentry->d_parent == pwd.dentry || !d_unhashed(pwd.dentry)) {
 		unsigned long len;
+		struct path tmp = root;
 		char * cwd;
 
-		cwd = __d_path(pwd.dentry, pwd.mnt, &root, page, PAGE_SIZE);
+		cwd = __d_path(&pwd, &tmp, page, PAGE_SIZE);
 		spin_unlock(&dcache_lock);
 
 		error = PTR_ERR(cwd);