| From | Greg Kroah-Hartman <> | Subject | [ 63/83] GFS2: Dont call file_accessed() with a shared glock | Date | Wed, 21 Nov 2012 16:42:25 -0800 |
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3.6-stable review patch. If anyone has any objections, please let me know.
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From: Benjamin Marzinski <bmarzins@redhat.com>
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>
--- fs/gfs2/file.c | 12 +++++------- fs/gfs2/super.c | 3 ++- 2 files changed, 7 insertions(+), 8 deletions(-)
--- a/fs/gfs2/file.c +++ b/fs/gfs2/file.c @@ -515,15 +515,13 @@ 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; vma->vm_flags |= VM_CAN_NONLINEAR; --- a/fs/gfs2/super.c +++ b/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);
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