ext{3,4}: Fix potential race when setversion ioctl updates inode

The EXT{3,4}_IOC_SETVERSION ioctl() updates i_ctime and i_generation
without i_mutex. This can lead to a race with the other operations that
update i_ctime. This is not a big issue but let's make the ioctl consistent
with how we handle e.g. other timestamp updates and use i_mutex to protect
inode changes.

Signed-off-by: Djalal Harouni <tixxdz@opendz.org>
Signed-off-by: Jan Kara <jack@suse.cz>

diff --git a/fs/ext3/ioctl.c b/fs/ext3/ioctl.c
index ba1b54e..e7b2ed9 100644 (file)
--- a/fs/ext3/ioctl.c
+++ b/fs/ext3/ioctl.c
@@ -134,10 +134,11 @@ flags_out:
                        goto setversion_out;
                }
 
+               mutex_lock(&inode->i_mutex);
                handle = ext3_journal_start(inode, 1);
                if (IS_ERR(handle)) {
                        err = PTR_ERR(handle);
-                       goto setversion_out;
+                       goto unlock_out;
                }
                err = ext3_reserve_inode_write(handle, inode, &iloc);
                if (err == 0) {
@@ -146,6 +147,9 @@ flags_out:
                        err = ext3_mark_iloc_dirty(handle, inode, &iloc);
                }
                ext3_journal_stop(handle);
+
+unlock_out:
+               mutex_unlock(&inode->i_mutex);
 setversion_out:
                mnt_drop_write(filp->f_path.mnt);
                return err;

diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c
index a567968..46a8de6 100644 (file)
--- a/fs/ext4/ioctl.c
+++ b/fs/ext4/ioctl.c
@@ -158,10 +158,11 @@ flags_out:
                        goto setversion_out;
                }
 
+               mutex_lock(&inode->i_mutex);
                handle = ext4_journal_start(inode, 1);
                if (IS_ERR(handle)) {
                        err = PTR_ERR(handle);
-                       goto setversion_out;
+                       goto unlock_out;
                }
                err = ext4_reserve_inode_write(handle, inode, &iloc);
                if (err == 0) {
@@ -170,6 +171,9 @@ flags_out:
                        err = ext4_mark_iloc_dirty(handle, inode, &iloc);
                }
                ext4_journal_stop(handle);
+
+unlock_out:
+               mutex_unlock(&inode->i_mutex);
 setversion_out:
                mnt_drop_write(filp->f_path.mnt);
                return err;