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 <bmarz...@redhat.com>
---
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);
