hfsplus: protect setflags using i_mutex

Use i_mutex for protecting against concurrent setflags ioctls like in
other filesystems and get rid of the BKL in hfsplus_ioctl.

Signed-off-by: Christoph Hellwig <hch@tuxera.com>

diff --git a/fs/hfsplus/ioctl.c b/fs/hfsplus/ioctl.c
index 0e359c3..906bd3d 100644 (file)
--- a/fs/hfsplus/ioctl.c
+++ b/fs/hfsplus/ioctl.c
@@ -17,7 +17,6 @@
 #include <linux/mount.h>
 #include <linux/sched.h>
 #include <linux/xattr.h>
-#include <linux/smp_lock.h>
 #include <asm/uaccess.h>
 #include "hfsplus_fs.h"
 
@@ -42,10 +41,9 @@ static int hfsplus_ioctl_setflags(struct file *file, int __user *user_flags)
        unsigned int flags;
        int err = 0;
 
-       lock_kernel();
        err = mnt_want_write(file->f_path.mnt);
        if (err)
-               goto out_unlock_kernel;
+               goto out;
 
        if (!is_owner_or_cap(inode)) {
                err = -EACCES;
@@ -57,18 +55,20 @@ static int hfsplus_ioctl_setflags(struct file *file, int __user *user_flags)
                goto out_drop_write;
        }
 
+       mutex_lock(&inode->i_mutex);
+
        if (flags & (FS_IMMUTABLE_FL|FS_APPEND_FL) ||
            HFSPLUS_I(inode).rootflags & (HFSPLUS_FLG_IMMUTABLE|HFSPLUS_FLG_APPEND)) {
                if (!capable(CAP_LINUX_IMMUTABLE)) {
                        err = -EPERM;
-                       goto out_drop_write;
+                       goto out_unlock_inode;
                }
        }
 
        /* don't silently ignore unsupported ext2 flags */
        if (flags & ~(FS_IMMUTABLE_FL|FS_APPEND_FL|FS_NODUMP_FL)) {
                err = -EOPNOTSUPP;
-               goto out_drop_write;
+               goto out_unlock_inode;
        }
        if (flags & FS_IMMUTABLE_FL) {
                inode->i_flags |= S_IMMUTABLE;
@@ -92,10 +92,11 @@ static int hfsplus_ioctl_setflags(struct file *file, int __user *user_flags)
        inode->i_ctime = CURRENT_TIME_SEC;
        mark_inode_dirty(inode);
 
+out_unlock_inode:
+       mutex_lock(&inode->i_mutex);
 out_drop_write:
        mnt_drop_write(file->f_path.mnt);
-out_unlock_kernel:
-       unlock_kernel();
+out:
        return err;
 }