On Wed, Sep 05, 2012 at 04:55:11PM -0400, J. Bruce Fields wrote:
> From: Jan Kara <jack@xxxxxxx>
>
> GFS2 uses i_mutex on its system quota inode to synchronize writes to
> quota file. Since this is an internal inode to GFS2 (not part of directory
> hiearchy or visible by user) we are safe to define locking rules for it. So
> let's just get it its own locking class to make it clear.
By the way, Steve, is there any reason you haven't taken this through
the gfs2 tree?
--b.
>
> CC: Steven Whitehouse <swhiteho@xxxxxxxxxx>
> Signed-off-by: Jan Kara <jack@xxxxxxx>
> Signed-off-by: J. Bruce Fields <bfields@xxxxxxxxxx>
> ---
> fs/gfs2/ops_fstype.c | 8 ++++++++
> fs/gfs2/quota.c | 2 +-
> 2 files changed, 9 insertions(+), 1 deletion(-)
>
> diff --git a/fs/gfs2/ops_fstype.c b/fs/gfs2/ops_fstype.c
> index e5af9dc..e443966 100644
> --- a/fs/gfs2/ops_fstype.c
> +++ b/fs/gfs2/ops_fstype.c
> @@ -19,6 +19,7 @@
> #include <linux/mount.h>
> #include <linux/gfs2_ondisk.h>
> #include <linux/quotaops.h>
> +#include <linux/lockdep.h>
>
> #include "gfs2.h"
> #include "incore.h"
> @@ -766,6 +767,7 @@ fail:
> return error;
> }
>
> +static struct lock_class_key gfs2_quota_imutex_key;
>
> static int init_inodes(struct gfs2_sbd *sdp, int undo)
> {
> @@ -803,6 +805,12 @@ static int init_inodes(struct gfs2_sbd *sdp, int undo)
> fs_err(sdp, "can't get quota file inode: %d\n", error);
> goto fail_rindex;
> }
> + /*
> + * i_mutex on quota files is special. Since this inode is hidden system
> + * file, we are safe to define locking ourselves.
> + */
> + lockdep_set_class(&sdp->sd_quota_inode->i_mutex,
> + &gfs2_quota_imutex_key);
>
> error = gfs2_rindex_update(sdp);
> if (error)
> diff --git a/fs/gfs2/quota.c b/fs/gfs2/quota.c
> index a3bde91..3d9c989 100644
> --- a/fs/gfs2/quota.c
> +++ b/fs/gfs2/quota.c
> @@ -781,7 +781,7 @@ static int do_sync(unsigned int num_qd, struct gfs2_quota_data **qda)
> return -ENOMEM;
>
> sort(qda, num_qd, sizeof(struct gfs2_quota_data *), sort_qd, NULL);
> - mutex_lock_nested(&ip->i_inode.i_mutex, I_MUTEX_QUOTA);
> + mutex_lock(&ip->i_inode.i_mutex);
> for (qx = 0; qx < num_qd; qx++) {
> error = gfs2_glock_nq_init(qda[qx]->qd_gl, LM_ST_EXCLUSIVE,
> GL_NOCACHE, &ghs[qx]);
> --
> 1.7.9.5
>
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