[PATCH] quota semaphore fix

The second quota locking fix.  Sorry, I seem to have misplaced the
changelog.

fs/ext2/inode.c

@@ -1239,6 +1239,12 @@ int ext2_setattr(struct dentry *dentry, struct iattr *iattr)
 	error = inode_change_ok(inode, iattr);
 	if (error)
 		return error;
+	if ((iattr->ia_valid & ATTR_UID && iattr->ia_uid != inode->i_uid) ||
+	    (iattr->ia_valid & ATTR_GID && iattr->ia_gid != inode->i_gid)) {
+		error = DQUOT_TRANSFER(inode, iattr) ? -EDQUOT : 0;
+		if (error)
+			return error;
+	}
 	inode_setattr(inode, iattr);
 	if (iattr->ia_valid & ATTR_MODE)
 		error = ext2_acl_chmod(inode);

fs/quota.c

@@ -123,13 +123,13 @@ static int do_quotactl(struct super_block *sb, int type, int cmd, qid_t id, cadd
 		case Q_GETFMT: {
 			__u32 fmt;
 
-			down_read(&sb_dqopt(sb)->dqoff_sem);
+			down_read(&sb_dqopt(sb)->dqptr_sem);
 			if (!sb_has_quota_enabled(sb, type)) {
-				up_read(&sb_dqopt(sb)->dqoff_sem);
+				up_read(&sb_dqopt(sb)->dqptr_sem);
 				return -ESRCH;
 			}
 			fmt = sb_dqopt(sb)->info[type].dqi_format->qf_fmt_id;
-			up_read(&sb_dqopt(sb)->dqoff_sem);
+			up_read(&sb_dqopt(sb)->dqptr_sem);
 			if (copy_to_user(addr, &fmt, sizeof(fmt)))
 				return -EFAULT;
 			return 0;

fs/super.c

@@ -71,7 +71,8 @@ static struct super_block *alloc_super(void)
 		atomic_set(&s->s_active, 1);
 		sema_init(&s->s_vfs_rename_sem,1);
 		sema_init(&s->s_dquot.dqio_sem, 1);
-		init_rwsem(&s->s_dquot.dqoff_sem);
+		sema_init(&s->s_dquot.dqonoff_sem, 1);
+		init_rwsem(&s->s_dquot.dqptr_sem);
 		s->s_maxbytes = MAX_NON_LFS;
 		s->dq_op = sb_dquot_ops;
 		s->s_qcop = sb_quotactl_ops;

include/linux/quota.h

@@ -280,7 +280,8 @@ struct quota_format_type {
 struct quota_info {
 	unsigned int flags;			/* Flags for diskquotas on this device */
 	struct semaphore dqio_sem;		/* lock device while I/O in progress */
-	struct rw_semaphore dqoff_sem;		/* serialize quota_off() and quota_on() on device and ops using quota_info struct, pointers from inode to dquots */
+	struct semaphore dqonoff_sem;		/* Serialize quotaon & quotaoff */
+	struct rw_semaphore dqptr_sem;		/* serialize ops using quota_info struct, pointers from inode to dquots */
 	struct file *files[MAXQUOTAS];		/* fp's to quotafiles */
 	struct mem_dqinfo info[MAXQUOTAS];	/* Information for each quota type */
 	struct quota_format_ops *ops[MAXQUOTAS];	/* Operations for each type */