From mboxrd@z Thu Jan 1 00:00:00 1970 From: Benjamin Marzinski Date: Tue, 6 Nov 2012 00:49:28 -0600 Subject: [Cluster-devel] [PATCH] GFS2: Don't call file_accessed() with a shared glock Message-ID: <20121106064928.GN5182@ether.msp.redhat.com> List-Id: To: cluster-devel.redhat.com MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit file_accessed() was being called by gfs2_mmap() with a shared glock. If it needed to update the atime, it was crashing because it dirtied the inode in gfs2_dirty_inode() without holding an exclusive lock. gfs2_dirty_inode() checked if the caller was already holding a glock, but it didn't make sure that the glock was in the exclusive state. Now, instead of calling file_accessed() while holding the shared lock in gfs2_mmap(), file_accessed() is called after grabbing and releasing the glock to update the inode. If file_accessed() needs to update the atime, it will grab an exclusive lock in gfs2_dirty_inode(). gfs2_dirty_inode() now also checks to make sure that if the calling process has already locked the glock, it has an exclusive lock. Signed-off-by: Benjamin Marzinski --- fs/gfs2/file.c | 12 +++++------- fs/gfs2/super.c | 3 ++- 2 files changed, 7 insertions(+), 8 deletions(-) Index: gfs2-3.0-nmw/fs/gfs2/file.c =================================================================== --- gfs2-3.0-nmw.orig/fs/gfs2/file.c +++ gfs2-3.0-nmw/fs/gfs2/file.c @@ -516,15 +516,13 @@ static int gfs2_mmap(struct file *file, struct gfs2_holder i_gh; int error; - gfs2_holder_init(ip->i_gl, LM_ST_SHARED, LM_FLAG_ANY, &i_gh); - error = gfs2_glock_nq(&i_gh); - if (error == 0) { - file_accessed(file); - gfs2_glock_dq(&i_gh); - } - gfs2_holder_uninit(&i_gh); + error = gfs2_glock_nq_init(ip->i_gl, LM_ST_SHARED, LM_FLAG_ANY, + &i_gh); if (error) return error; + /* grab lock to update inode */ + gfs2_glock_dq_uninit(&i_gh); + file_accessed(file); } vma->vm_ops = &gfs2_vm_ops; Index: gfs2-3.0-nmw/fs/gfs2/super.c =================================================================== --- gfs2-3.0-nmw.orig/fs/gfs2/super.c +++ gfs2-3.0-nmw/fs/gfs2/super.c @@ -810,7 +810,8 @@ static void gfs2_dirty_inode(struct inod return; } need_unlock = 1; - } + } else if (WARN_ON_ONCE(ip->i_gl->gl_state != LM_ST_EXCLUSIVE)) + return; if (current->journal_info == NULL) { ret = gfs2_trans_begin(sdp, RES_DINODE, 0);