Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
[linux.git] / fs / namei.c
index 4fb52f0ca5cbfb831f0e681ee7ab5c4477a04a6e..c6157c894fce234c333d5a2d787f81ee3e5e7ba9 100644 (file)
@@ -1801,7 +1801,7 @@ static int link_path_walk(const char *name, struct nameidata *nd)
                        if (err)
                                return err;
                }
-               if (!d_is_directory(nd->path.dentry)) {
+               if (!d_can_lookup(nd->path.dentry)) {
                        err = -ENOTDIR; 
                        break;
                }
@@ -1822,7 +1822,7 @@ static int path_init(int dfd, const char *name, unsigned int flags,
                struct dentry *root = nd->root.dentry;
                struct inode *inode = root->d_inode;
                if (*name) {
-                       if (!d_is_directory(root))
+                       if (!d_can_lookup(root))
                                return -ENOTDIR;
                        retval = inode_permission(inode, MAY_EXEC);
                        if (retval)
@@ -1878,7 +1878,7 @@ static int path_init(int dfd, const char *name, unsigned int flags,
                dentry = f.file->f_path.dentry;
 
                if (*name) {
-                       if (!d_is_directory(dentry)) {
+                       if (!d_can_lookup(dentry)) {
                                fdput(f);
                                return -ENOTDIR;
                        }
@@ -1960,7 +1960,7 @@ static int path_lookupat(int dfd, const char *name,
                err = complete_walk(nd);
 
        if (!err && nd->flags & LOOKUP_DIRECTORY) {
-               if (!d_is_directory(nd->path.dentry)) {
+               if (!d_can_lookup(nd->path.dentry)) {
                        path_put(&nd->path);
                        err = -ENOTDIR;
                }
@@ -2423,11 +2423,11 @@ static int may_delete(struct inode *dir, struct dentry *victim, bool isdir)
            IS_IMMUTABLE(inode) || IS_SWAPFILE(inode))
                return -EPERM;
        if (isdir) {
-               if (!d_is_directory(victim) && !d_is_autodir(victim))
+               if (!d_is_dir(victim))
                        return -ENOTDIR;
                if (IS_ROOT(victim))
                        return -EBUSY;
-       } else if (d_is_directory(victim) || d_is_autodir(victim))
+       } else if (d_is_dir(victim))
                return -EISDIR;
        if (IS_DEADDIR(dir))
                return -ENOENT;
@@ -2581,7 +2581,7 @@ static int handle_truncate(struct file *filp)
        /*
         * Refuse to truncate files with mandatory locks held on them.
         */
-       error = locks_verify_locked(inode);
+       error = locks_verify_locked(filp);
        if (!error)
                error = security_path_truncate(path);
        if (!error) {
@@ -3028,11 +3028,10 @@ finish_open:
        }
        audit_inode(name, nd->path.dentry, 0);
        error = -EISDIR;
-       if ((open_flag & O_CREAT) &&
-           (d_is_directory(nd->path.dentry) || d_is_autodir(nd->path.dentry)))
+       if ((open_flag & O_CREAT) && d_is_dir(nd->path.dentry))
                goto out;
        error = -ENOTDIR;
-       if ((nd->flags & LOOKUP_DIRECTORY) && !d_is_directory(nd->path.dentry))
+       if ((nd->flags & LOOKUP_DIRECTORY) && !d_can_lookup(nd->path.dentry))
                goto out;
        if (!S_ISREG(nd->inode->i_mode))
                will_truncate = false;
@@ -3761,7 +3760,7 @@ exit1:
 slashes:
        if (d_is_negative(dentry))
                error = -ENOENT;
-       else if (d_is_directory(dentry) || d_is_autodir(dentry))
+       else if (d_is_dir(dentry))
                error = -EISDIR;
        else
                error = -ENOTDIR;
@@ -3993,7 +3992,28 @@ SYSCALL_DEFINE2(link, const char __user *, oldname, const char __user *, newname
        return sys_linkat(AT_FDCWD, oldname, AT_FDCWD, newname, 0);
 }
 
-/*
+/**
+ * vfs_rename - rename a filesystem object
+ * @old_dir:   parent of source
+ * @old_dentry:        source
+ * @new_dir:   parent of destination
+ * @new_dentry:        destination
+ * @delegated_inode: returns an inode needing a delegation break
+ * @flags:     rename flags
+ *
+ * The caller must hold multiple mutexes--see lock_rename()).
+ *
+ * If vfs_rename discovers a delegation in need of breaking at either
+ * the source or destination, it will return -EWOULDBLOCK and return a
+ * reference to the inode in delegated_inode.  The caller should then
+ * break the delegation and retry.  Because breaking a delegation may
+ * take a long time, the caller should drop all locks before doing
+ * so.
+ *
+ * Alternatively, a caller may pass NULL for delegated_inode.  This may
+ * be appropriate for callers that expect the underlying filesystem not
+ * to be NFS exported.
+ *
  * The worst of all namespace operations - renaming directory. "Perverted"
  * doesn't even start to describe it. Somebody in UCB had a heck of a trip...
  * Problems:
@@ -4021,164 +4041,140 @@ SYSCALL_DEFINE2(link, const char __user *, oldname, const char __user *, newname
  *        ->i_mutex on parents, which works but leads to some truly excessive
  *        locking].
  */
-static int vfs_rename_dir(struct inode *old_dir, struct dentry *old_dentry,
-                         struct inode *new_dir, struct dentry *new_dentry)
+int vfs_rename(struct inode *old_dir, struct dentry *old_dentry,
+              struct inode *new_dir, struct dentry *new_dentry,
+              struct inode **delegated_inode, unsigned int flags)
 {
-       int error = 0;
+       int error;
+       bool is_dir = d_is_dir(old_dentry);
+       const unsigned char *old_name;
+       struct inode *source = old_dentry->d_inode;
        struct inode *target = new_dentry->d_inode;
+       bool new_is_dir = false;
        unsigned max_links = new_dir->i_sb->s_max_links;
 
+       if (source == target)
+               return 0;
+
+       error = may_delete(old_dir, old_dentry, is_dir);
+       if (error)
+               return error;
+
+       if (!target) {
+               error = may_create(new_dir, new_dentry);
+       } else {
+               new_is_dir = d_is_dir(new_dentry);
+
+               if (!(flags & RENAME_EXCHANGE))
+                       error = may_delete(new_dir, new_dentry, is_dir);
+               else
+                       error = may_delete(new_dir, new_dentry, new_is_dir);
+       }
+       if (error)
+               return error;
+
+       if (!old_dir->i_op->rename)
+               return -EPERM;
+
+       if (flags && !old_dir->i_op->rename2)
+               return -EINVAL;
+
        /*
         * If we are going to change the parent - check write permissions,
         * we'll need to flip '..'.
         */
        if (new_dir != old_dir) {
-               error = inode_permission(old_dentry->d_inode, MAY_WRITE);
-               if (error)
-                       return error;
+               if (is_dir) {
+                       error = inode_permission(source, MAY_WRITE);
+                       if (error)
+                               return error;
+               }
+               if ((flags & RENAME_EXCHANGE) && new_is_dir) {
+                       error = inode_permission(target, MAY_WRITE);
+                       if (error)
+                               return error;
+               }
        }
 
-       error = security_inode_rename(old_dir, old_dentry, new_dir, new_dentry);
+       error = security_inode_rename(old_dir, old_dentry, new_dir, new_dentry,
+                                     flags);
        if (error)
                return error;
 
+       old_name = fsnotify_oldname_init(old_dentry->d_name.name);
        dget(new_dentry);
-       if (target)
+       if (!is_dir || (flags & RENAME_EXCHANGE))
+               lock_two_nondirectories(source, target);
+       else if (target)
                mutex_lock(&target->i_mutex);
 
        error = -EBUSY;
        if (d_mountpoint(old_dentry) || d_mountpoint(new_dentry))
                goto out;
 
-       error = -EMLINK;
-       if (max_links && !target && new_dir != old_dir &&
-           new_dir->i_nlink >= max_links)
-               goto out;
-
-       if (target)
+       if (max_links && new_dir != old_dir) {
+               error = -EMLINK;
+               if (is_dir && !new_is_dir && new_dir->i_nlink >= max_links)
+                       goto out;
+               if ((flags & RENAME_EXCHANGE) && !is_dir && new_is_dir &&
+                   old_dir->i_nlink >= max_links)
+                       goto out;
+       }
+       if (is_dir && !(flags & RENAME_EXCHANGE) && target)
                shrink_dcache_parent(new_dentry);
-       error = old_dir->i_op->rename(old_dir, old_dentry, new_dir, new_dentry);
-       if (error)
-               goto out;
-
-       if (target) {
-               target->i_flags |= S_DEAD;
-               dont_mount(new_dentry);
+       if (!is_dir) {
+               error = try_break_deleg(source, delegated_inode);
+               if (error)
+                       goto out;
        }
-out:
-       if (target)
-               mutex_unlock(&target->i_mutex);
-       dput(new_dentry);
-       if (!error)
-               if (!(old_dir->i_sb->s_type->fs_flags & FS_RENAME_DOES_D_MOVE))
-                       d_move(old_dentry,new_dentry);
-       return error;
-}
-
-static int vfs_rename_other(struct inode *old_dir, struct dentry *old_dentry,
-                           struct inode *new_dir, struct dentry *new_dentry,
-                           struct inode **delegated_inode)
-{
-       struct inode *target = new_dentry->d_inode;
-       struct inode *source = old_dentry->d_inode;
-       int error;
-
-       error = security_inode_rename(old_dir, old_dentry, new_dir, new_dentry);
-       if (error)
-               return error;
-
-       dget(new_dentry);
-       lock_two_nondirectories(source, target);
-
-       error = -EBUSY;
-       if (d_mountpoint(old_dentry)||d_mountpoint(new_dentry))
-               goto out;
-
-       error = try_break_deleg(source, delegated_inode);
-       if (error)
-               goto out;
-       if (target) {
+       if (target && !new_is_dir) {
                error = try_break_deleg(target, delegated_inode);
                if (error)
                        goto out;
        }
-       error = old_dir->i_op->rename(old_dir, old_dentry, new_dir, new_dentry);
+       if (!flags) {
+               error = old_dir->i_op->rename(old_dir, old_dentry,
+                                             new_dir, new_dentry);
+       } else {
+               error = old_dir->i_op->rename2(old_dir, old_dentry,
+                                              new_dir, new_dentry, flags);
+       }
        if (error)
                goto out;
 
-       if (target)
+       if (!(flags & RENAME_EXCHANGE) && target) {
+               if (is_dir)
+                       target->i_flags |= S_DEAD;
                dont_mount(new_dentry);
-       if (!(old_dir->i_sb->s_type->fs_flags & FS_RENAME_DOES_D_MOVE))
-               d_move(old_dentry, new_dentry);
+       }
+       if (!(old_dir->i_sb->s_type->fs_flags & FS_RENAME_DOES_D_MOVE)) {
+               if (!(flags & RENAME_EXCHANGE))
+                       d_move(old_dentry, new_dentry);
+               else
+                       d_exchange(old_dentry, new_dentry);
+       }
 out:
-       unlock_two_nondirectories(source, target);
+       if (!is_dir || (flags & RENAME_EXCHANGE))
+               unlock_two_nondirectories(source, target);
+       else if (target)
+               mutex_unlock(&target->i_mutex);
        dput(new_dentry);
-       return error;
-}
-
-/**
- * vfs_rename - rename a filesystem object
- * @old_dir:   parent of source
- * @old_dentry:        source
- * @new_dir:   parent of destination
- * @new_dentry:        destination
- * @delegated_inode: returns an inode needing a delegation break
- *
- * The caller must hold multiple mutexes--see lock_rename()).
- *
- * If vfs_rename discovers a delegation in need of breaking at either
- * the source or destination, it will return -EWOULDBLOCK and return a
- * reference to the inode in delegated_inode.  The caller should then
- * break the delegation and retry.  Because breaking a delegation may
- * take a long time, the caller should drop all locks before doing
- * so.
- *
- * Alternatively, a caller may pass NULL for delegated_inode.  This may
- * be appropriate for callers that expect the underlying filesystem not
- * to be NFS exported.
- */
-int vfs_rename(struct inode *old_dir, struct dentry *old_dentry,
-              struct inode *new_dir, struct dentry *new_dentry,
-              struct inode **delegated_inode)
-{
-       int error;
-       int is_dir = d_is_directory(old_dentry) || d_is_autodir(old_dentry);
-       const unsigned char *old_name;
-
-       if (old_dentry->d_inode == new_dentry->d_inode)
-               return 0;
-       error = may_delete(old_dir, old_dentry, is_dir);
-       if (error)
-               return error;
-
-       if (!new_dentry->d_inode)
-               error = may_create(new_dir, new_dentry);
-       else
-               error = may_delete(new_dir, new_dentry, is_dir);
-       if (error)
-               return error;
-
-       if (!old_dir->i_op->rename)
-               return -EPERM;
-
-       old_name = fsnotify_oldname_init(old_dentry->d_name.name);
-
-       if (is_dir)
-               error = vfs_rename_dir(old_dir,old_dentry,new_dir,new_dentry);
-       else
-               error = vfs_rename_other(old_dir,old_dentry,new_dir,new_dentry,delegated_inode);
-       if (!error)
+       if (!error) {
                fsnotify_move(old_dir, new_dir, old_name, is_dir,
-                             new_dentry->d_inode, old_dentry);
+                             !(flags & RENAME_EXCHANGE) ? target : NULL, old_dentry);
+               if (flags & RENAME_EXCHANGE) {
+                       fsnotify_move(new_dir, old_dir, old_dentry->d_name.name,
+                                     new_is_dir, NULL, new_dentry);
+               }
+       }
        fsnotify_oldname_free(old_name);
 
        return error;
 }
 EXPORT_SYMBOL(vfs_rename);
 
-SYSCALL_DEFINE4(renameat, int, olddfd, const char __user *, oldname,
-               int, newdfd, const char __user *, newname)
+SYSCALL_DEFINE5(renameat2, int, olddfd, const char __user *, oldname,
+               int, newdfd, const char __user *, newname, unsigned int, flags)
 {
        struct dentry *old_dir, *new_dir;
        struct dentry *old_dentry, *new_dentry;
@@ -4190,6 +4186,13 @@ SYSCALL_DEFINE4(renameat, int, olddfd, const char __user *, oldname,
        unsigned int lookup_flags = 0;
        bool should_retry = false;
        int error;
+
+       if (flags & ~(RENAME_NOREPLACE | RENAME_EXCHANGE))
+               return -EINVAL;
+
+       if ((flags & RENAME_NOREPLACE) && (flags & RENAME_EXCHANGE))
+               return -EINVAL;
+
 retry:
        from = user_path_parent(olddfd, oldname, &oldnd, lookup_flags);
        if (IS_ERR(from)) {
@@ -4213,6 +4216,8 @@ retry:
                goto exit2;
 
        new_dir = newnd.path.dentry;
+       if (flags & RENAME_NOREPLACE)
+               error = -EEXIST;
        if (newnd.last_type != LAST_NORM)
                goto exit2;
 
@@ -4222,7 +4227,8 @@ retry:
 
        oldnd.flags &= ~LOOKUP_PARENT;
        newnd.flags &= ~LOOKUP_PARENT;
-       newnd.flags |= LOOKUP_RENAME_TARGET;
+       if (!(flags & RENAME_EXCHANGE))
+               newnd.flags |= LOOKUP_RENAME_TARGET;
 
 retry_deleg:
        trap = lock_rename(new_dir, old_dir);
@@ -4235,34 +4241,49 @@ retry_deleg:
        error = -ENOENT;
        if (d_is_negative(old_dentry))
                goto exit4;
+       new_dentry = lookup_hash(&newnd);
+       error = PTR_ERR(new_dentry);
+       if (IS_ERR(new_dentry))
+               goto exit4;
+       error = -EEXIST;
+       if ((flags & RENAME_NOREPLACE) && d_is_positive(new_dentry))
+               goto exit5;
+       if (flags & RENAME_EXCHANGE) {
+               error = -ENOENT;
+               if (d_is_negative(new_dentry))
+                       goto exit5;
+
+               if (!d_is_dir(new_dentry)) {
+                       error = -ENOTDIR;
+                       if (newnd.last.name[newnd.last.len])
+                               goto exit5;
+               }
+       }
        /* unless the source is a directory trailing slashes give -ENOTDIR */
-       if (!d_is_directory(old_dentry) && !d_is_autodir(old_dentry)) {
+       if (!d_is_dir(old_dentry)) {
                error = -ENOTDIR;
                if (oldnd.last.name[oldnd.last.len])
-                       goto exit4;
-               if (newnd.last.name[newnd.last.len])
-                       goto exit4;
+                       goto exit5;
+               if (!(flags & RENAME_EXCHANGE) && newnd.last.name[newnd.last.len])
+                       goto exit5;
        }
        /* source should not be ancestor of target */
        error = -EINVAL;
        if (old_dentry == trap)
-               goto exit4;
-       new_dentry = lookup_hash(&newnd);
-       error = PTR_ERR(new_dentry);
-       if (IS_ERR(new_dentry))
-               goto exit4;
+               goto exit5;
        /* target should not be an ancestor of source */
-       error = -ENOTEMPTY;
+       if (!(flags & RENAME_EXCHANGE))
+               error = -ENOTEMPTY;
        if (new_dentry == trap)
                goto exit5;
 
        error = security_path_rename(&oldnd.path, old_dentry,
-                                    &newnd.path, new_dentry);
+                                    &newnd.path, new_dentry, flags);
        if (error)
                goto exit5;
        error = vfs_rename(old_dir->d_inode, old_dentry,
-                                  new_dir->d_inode, new_dentry,
-                                  &delegated_inode);
+                          new_dir->d_inode, new_dentry,
+                          &delegated_inode, flags);
 exit5:
        dput(new_dentry);
 exit4:
@@ -4292,9 +4313,15 @@ exit:
        return error;
 }
 
+SYSCALL_DEFINE4(renameat, int, olddfd, const char __user *, oldname,
+               int, newdfd, const char __user *, newname)
+{
+       return sys_renameat2(olddfd, oldname, newdfd, newname, 0);
+}
+
 SYSCALL_DEFINE2(rename, const char __user *, oldname, const char __user *, newname)
 {
-       return sys_renameat(AT_FDCWD, oldname, AT_FDCWD, newname);
+       return sys_renameat2(AT_FDCWD, oldname, AT_FDCWD, newname, 0);
 }
 
 int readlink_copy(char __user *buffer, int buflen, const char *link)