GFS2: Don't call file_accessed() with a shared glock

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 <bmarzins@redhat.com>
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>

diff --git a/fs/gfs2/file.c b/fs/gfs2/file.c
index 377a68dbd066f4b318d8b61472869c270eb7198b..e056b4ce487777bbe794d64a11e4cbe2756205d3 100644 (file)
--- a/fs/gfs2/file.c
+++ b/fs/gfs2/file.c
@@ -516,15 +516,13 @@ static int gfs2_mmap(struct file *file, struct vm_area_struct *vma)
                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;
 

diff --git a/fs/gfs2/super.c b/fs/gfs2/super.c
index bc737261f234872ad2df43411e6e74296b26b61c..d6488674d916273398b0bf8bd9cd3b2328c8a1fb 100644 (file)
--- a/fs/gfs2/super.c
+++ b/fs/gfs2/super.c
@@ -810,7 +810,8 @@ static void gfs2_dirty_inode(struct inode *inode, int flags)
                        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);