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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>
This commit is contained in:
Benjamin Marzinski 2012-11-06 00:49:28 -06:00 committed by Steven Whitehouse
parent 076f0faa76
commit 3d1626889a
2 changed files with 7 additions and 8 deletions
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12
fs/gfs2/file.c
View File

@ -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;

3
fs/gfs2/super.c
View File

@ -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);