1 files changed, 80 insertions, 70 deletions

diff --git a/fs/dcache.c b/fs/dcache.c
index d68631f18df1..b5f613932912 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -1739,45 +1739,41 @@ shouldnt_be_hashed:
  * @rootmnt: vfsmnt to which the root dentry belongs
  * @buffer: buffer to return value in
  * @buflen: buffer length
+ * @fail_deleted: what to return for deleted files
  *
- * Convert a dentry into an ASCII path name. If the entry has been deleted
- * the string " (deleted)" is appended. Note that this is ambiguous.
+ * Convert a dentry into an ASCII path name. If the entry has been deleted,
+ * then if @fail_deleted is true, ERR_PTR(-ENOENT) is returned. Otherwise,
+ * the the string " (deleted)" is appended. Note that this is ambiguous.
  *
- * Returns the buffer or an error code if the path was too long.
- *
- * "buflen" should be positive. Caller holds the dcache_lock.
+ * Returns the buffer or an error code.
  */
-static char * __d_path( struct dentry *dentry, struct vfsmount *vfsmnt,
-                        struct dentry *root, struct vfsmount *rootmnt,
-                        char *buffer, int buflen)
+static char *__d_path(struct dentry *dentry, struct vfsmount *vfsmnt,
+                      struct dentry *root, struct vfsmount *rootmnt,
+                      char *buffer, int buflen, int fail_deleted)
 {
-        char * end = buffer+buflen;
-        char * retval;
-        int namelen;
+        int namelen, is_slash;
+
+        if (buflen < 2)
+                return ERR_PTR(-ENAMETOOLONG);
+        buffer += --buflen;
+        *buffer = '\0';
 
-        *--end = '\0';
-        buflen--;
+        spin_lock(&dcache_lock);
         if (!IS_ROOT(dentry) && d_unhashed(dentry)) {
-                buflen -= 10;
-                end -= 10;
-                if (buflen < 0)
+                if (fail_deleted) {
+                        buffer = ERR_PTR(-ENOENT);
+                        goto out;
+                }
+                if (buflen < 10)
                         goto Elong;
-                memcpy(end, " (deleted)", 10);
+                buflen -= 10;
+                buffer -= 10;
+                memcpy(buffer, " (deleted)", 10);
         }
-
-        if (buflen < 1)
-                goto Elong;
-        /* Get '/' right */
-        retval = end-1;
-        *retval = '/';
-
-        for (;;) {
+        while (dentry != root || vfsmnt != rootmnt) {
                 struct dentry * parent;
 
-                if (dentry == root && vfsmnt == rootmnt)
-                        break;
                 if (dentry == vfsmnt->mnt_root || IS_ROOT(dentry)) {
-                        /* Global root? */
                         spin_lock(&vfsmount_lock);
                         if (vfsmnt->mnt_parent == vfsmnt) {
                                 spin_unlock(&vfsmount_lock);
@@ -1791,33 +1787,60 @@ 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 (buflen <= namelen)
                         goto Elong;
-                end -= namelen;
-                memcpy(end, dentry->d_name.name, namelen);
-                *--end = '/';
-                retval = end;
+                buflen -= namelen + 1;
+                buffer -= namelen;
+                memcpy(buffer, dentry->d_name.name, namelen);
+                *--buffer = '/';
                 dentry = parent;
         }
+        /* Get '/' right */
+        if (*buffer != '/')
+                *--buffer = '/';
 
-        return retval;
+out:
+        spin_unlock(&dcache_lock);
+        return buffer;
 
 global_root:
+        /*
+         * We went past the (vfsmount, dentry) we were looking for and have
+         * either hit a root dentry, a lazily unmounted dentry, an
+         * unconnected dentry, or the file is on a pseudo filesystem.
+         */
         namelen = dentry->d_name.len;
-        buflen -= namelen;
-        if (buflen < 0)
+        is_slash = (namelen == 1 && *dentry->d_name.name == '/');
+        if (is_slash || (dentry->d_sb->s_flags & MS_NOUSER)) {
+                /*
+                 * Make sure we won't return a pathname starting with '/'.
+                 *
+                 * Historically, we also glue together the root dentry and
+                 * remaining name for pseudo filesystems like pipefs, which
+                 * have the MS_NOUSER flag set. This results in pathnames
+                 * like "pipe:[439336]".
+                 */
+                if (*buffer == '/') {
+                        buffer++;
+                        buflen++;
+                }
+                if (is_slash)
+                        goto out;
+        }
+        if (buflen < namelen)
                 goto Elong;
-        retval -= namelen-1;    /* hit the slash */
-        memcpy(retval, dentry->d_name.name, namelen);
-        return retval;
+        buffer -= namelen;
+        memcpy(buffer, dentry->d_name.name, namelen);
+        goto out;
+
 Elong:
-        return ERR_PTR(-ENAMETOOLONG);
+        buffer = ERR_PTR(-ENAMETOOLONG);
+        goto out;
 }
 
 /* write full pathname into buffer and return start of pathname */
-char * d_path(struct dentry *dentry, struct vfsmount *vfsmnt,
-                                char *buf, int buflen)
+char *d_path(struct dentry *dentry, struct vfsmount *vfsmnt, char *buf,
+             int buflen)
 {
         char *res;
         struct vfsmount *rootmnt;
@@ -1827,9 +1850,7 @@ char * d_path(struct dentry *dentry, struct vfsmount *vfsmnt,
         rootmnt = mntget(current->fs->rootmnt);
         root = dget(current->fs->root);
         read_unlock(&current->fs->lock);
-        spin_lock(&dcache_lock);
-        res = __d_path(dentry, vfsmnt, root, rootmnt, buf, buflen);
-        spin_unlock(&dcache_lock);
+        res = __d_path(dentry, vfsmnt, root, rootmnt, buf, buflen, 0);
         dput(root);
         mntput(rootmnt);
         return res;
@@ -1855,10 +1876,10 @@ char * d_path(struct dentry *dentry, struct vfsmount *vfsmnt,
  */
 asmlinkage long sys_getcwd(char __user *buf, unsigned long size)
 {
-        int error;
+        int error, len;
         struct vfsmount *pwdmnt, *rootmnt;
         struct dentry *pwd, *root;
-        char *page = (char *) __get_free_page(GFP_USER);
+        char *page = (char *) __get_free_page(GFP_USER), *cwd;
 
         if (!page)
                 return -ENOMEM;
@@ -1870,29 +1891,18 @@ asmlinkage long sys_getcwd(char __user *buf, unsigned long size)
         root = dget(current->fs->root);
         read_unlock(&current->fs->lock);
 
-        error = -ENOENT;
-        /* Has the current directory has been unlinked? */
-        spin_lock(&dcache_lock);
-        if (pwd->d_parent == pwd || !d_unhashed(pwd)) {
-                unsigned long len;
-                char * cwd;
-
-                cwd = __d_path(pwd, pwdmnt, root, rootmnt, page, PAGE_SIZE);
-                spin_unlock(&dcache_lock);
-
-                error = PTR_ERR(cwd);
-                if (IS_ERR(cwd))
-                        goto out;
+        cwd = __d_path(pwd, pwdmnt, root, rootmnt, page, PAGE_SIZE, 1);
+        error = PTR_ERR(cwd);
+        if (IS_ERR(cwd))
+                goto out;
 
-                error = -ERANGE;
-                len = PAGE_SIZE + page - cwd;
-                if (len <= size) {
-                        error = len;
-                        if (copy_to_user(buf, cwd, len))
-                                error = -EFAULT;
-                }
-        } else
-                spin_unlock(&dcache_lock);
+        error = -ERANGE;
+        len = PAGE_SIZE + page - cwd;
+        if (len <= size) {
+                error = len;
+                if (copy_to_user(buf, cwd, len))
+                        error = -EFAULT;
+        }
 
 out:
         dput(pwd);