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

commit 3d1626889a64bd5a661544d582036a0a02104a60 upstream.

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/gfs2/file.c b/fs/gfs2/file.c
index 382000ffac1f7e892163665a27982e587b9d83e7..07cc71ffe5d99a8cde9a5c47eb11474b88b43c5f 100644 (file)
--- a/fs/gfs2/file.c
+++ b/fs/gfs2/file.c
@@ -515,15 +515,13 @@ 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;
        vma->vm_flags |= VM_CAN_NONLINEAR;

diff --git a/fs/gfs2/super.c b/fs/gfs2/super.c
index fc3168f47a146a978b733a2dd106aaf50706aeb7..12ff463cba0b953b4cac4642d481f09e666ecc62 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);