quota: Introduce DQUOT_QUOTA_SYS_FILE flag

If filesystem can handle quota files as system files hidden from users, we can skip a lot of cache invalidation, syncing, inode flags setting etc. when turning quotas on, off and quota_sync. Allow filesystem to indicate that it is hiding quota files from users by DQUOT_QUOTA_SYS_FILE flag. Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Mark Fasheh <mfasheh@suse.com>

quota: Introduce DQUOT_QUOTA_SYS_FILE flag
If filesystem can handle quota files as system files hidden from users, we can skip a lot of cache invalidation, syncing, inode flags setting etc. when turning quotas on, off and quota_sync. Allow filesystem to indicate that it is hiding quota files from users by DQUOT_QUOTA_SYS_FILE flag. Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Mark Fasheh <mfasheh@suse.com>
Jan Kara · Mark Fasheh
1 parent dcb30695f2
Showing 3 changed files with 40 additions and 15 deletions Side-by-side Diff
fs/dquot.c
fs/quota.c
include/linux/quota.h
@@ -1631,6 +1631,11 @@
 		dqopt->ops[cnt] = NULL;
 	}
 	mutex_unlock(&dqopt->dqonoff_mutex);
+
+	/* Skip syncing and setting flags if quota files are hidden */
+	if (dqopt->flags & DQUOT_QUOTA_SYS_FILE)
+		goto put_inodes;
+
 	/* Sync the superblock so that buffers with quota data are written to
 	 * disk (and so userspace sees correct data afterwards). */
 	if (sb->s_op->sync_fs)
@@ -1655,6 +1660,12 @@
 				mark_inode_dirty(toputinode[cnt]);
 			}
 			mutex_unlock(&dqopt->dqonoff_mutex);
+		}
+	if (sb->s_bdev)
+		invalidate_bdev(sb->s_bdev);
+put_inodes:
+	for (cnt = 0; cnt < MAXQUOTAS; cnt++)
+		if (toputinode[cnt]) {
 			/* On remount RO, we keep the inode pointer so that we
 			 * can reenable quota on the subsequent remount RW. We
 			 * have to check 'flags' variable and not use sb_has_
@@ -1667,8 +1678,6 @@
 			else if (!toputinode[cnt]->i_nlink)
 				ret = -EBUSY;
 		}
-	if (sb->s_bdev)
-		invalidate_bdev(sb->s_bdev);
 	return ret;
 }
  
  
@@ -1715,25 +1724,31 @@
 		goto out_fmt;
 	}
  
-	/* As we bypass the pagecache we must now flush the inode so that
-	 * we see all the changes from userspace... */
-	write_inode_now(inode, 1);
-	/* And now flush the block cache so that kernel sees the changes */
-	invalidate_bdev(sb->s_bdev);
+	if (!(dqopt->flags & DQUOT_QUOTA_SYS_FILE)) {
+		/* As we bypass the pagecache we must now flush the inode so
+		 * that we see all the changes from userspace... */
+		write_inode_now(inode, 1);
+		/* And now flush the block cache so that kernel sees the
+		 * changes */
+		invalidate_bdev(sb->s_bdev);
+	}
 	mutex_lock(&inode->i_mutex);
 	mutex_lock(&dqopt->dqonoff_mutex);
 	if (sb_has_quota_loaded(sb, type)) {
 		error = -EBUSY;
 		goto out_lock;
 	}
-	/* We don't want quota and atime on quota files (deadlocks possible)
-	 * Also nobody should write to the file - we use special IO operations
-	 * which ignore the immutable bit. */
-	down_write(&dqopt->dqptr_sem);
-	oldflags = inode->i_flags & (S_NOATIME | S_IMMUTABLE | S_NOQUOTA);
-	inode->i_flags |= S_NOQUOTA | S_NOATIME | S_IMMUTABLE;
-	up_write(&dqopt->dqptr_sem);
-	sb->dq_op->drop(inode);
+
+	if (!(dqopt->flags & DQUOT_QUOTA_SYS_FILE)) {
+		/* We don't want quota and atime on quota files (deadlocks
+		 * possible) Also nobody should write to the file - we use
+		 * special IO operations which ignore the immutable bit. */
+		down_write(&dqopt->dqptr_sem);
+		oldflags = inode->i_flags & (S_NOATIME | S_IMMUTABLE | S_NOQUOTA);
+		inode->i_flags |= S_NOQUOTA | S_NOATIME | S_IMMUTABLE;
+		up_write(&dqopt->dqptr_sem);
+		sb->dq_op->drop(inode);
+	}
  
 	error = -EIO;
 	dqopt->files[type] = igrab(inode);
@@ -160,6 +160,9 @@
 	int cnt;
  
 	sb->s_qcop->quota_sync(sb, type);
+
+	if (sb_dqopt(sb)->flags & DQUOT_QUOTA_SYS_FILE)
+		return;
 	/* This is not very clever (and fast) but currently I don't know about
 	 * any other simple way of getting quota data to disk and we must get
 	 * them there for userspace to be visible... */
@@ -332,6 +332,13 @@
 #define DQUOT_SUSPENDED		(1 << _DQUOT_SUSPENDED)
 #define DQUOT_STATE_FLAGS	(DQUOT_USAGE_ENABLED | DQUOT_LIMITS_ENABLED | \
 				 DQUOT_SUSPENDED)
+/* Other quota flags */
+#define DQUOT_QUOTA_SYS_FILE	(1 << 6)	/* Quota file is a special
+						 * system file and user cannot
+						 * touch it. Filesystem is
+						 * responsible for setting
+						 * S_NOQUOTA, S_NOATIME flags
+						 */
  
 static inline unsigned int dquot_state_flag(unsigned int flags, int type)
 {
...	...	@@ -1631,6 +1631,11 @@
1631	1631	dqopt->ops[cnt] = NULL;
1632	1632	}
1633	1633	mutex_unlock(&dqopt->dqonoff_mutex);
	1634	+
	1635	+ /* Skip syncing and setting flags if quota files are hidden */
	1636	+ if (dqopt->flags & DQUOT_QUOTA_SYS_FILE)
	1637	+ goto put_inodes;
	1638	+
1634	1639	/* Sync the superblock so that buffers with quota data are written to
1635	1640	* disk (and so userspace sees correct data afterwards). */
1636	1641	if (sb->s_op->sync_fs)
...	...	@@ -1655,6 +1660,12 @@
1655	1660	mark_inode_dirty(toputinode[cnt]);
1656	1661	}
1657	1662	mutex_unlock(&dqopt->dqonoff_mutex);
	1663	+ }
	1664	+ if (sb->s_bdev)
	1665	+ invalidate_bdev(sb->s_bdev);
	1666	+put_inodes:
	1667	+ for (cnt = 0; cnt < MAXQUOTAS; cnt++)
	1668	+ if (toputinode[cnt]) {
1658	1669	/* On remount RO, we keep the inode pointer so that we
1659	1670	* can reenable quota on the subsequent remount RW. We
1660	1671	* have to check 'flags' variable and not use sb_has_
...	...	@@ -1667,8 +1678,6 @@
1667	1678	else if (!toputinode[cnt]->i_nlink)
1668	1679	ret = -EBUSY;
1669	1680	}
1670		- if (sb->s_bdev)
1671		- invalidate_bdev(sb->s_bdev);
1672	1681	return ret;
1673	1682	}
1674	1683
1675	1684
...	...	@@ -1715,25 +1724,31 @@
1715	1724	goto out_fmt;
1716	1725	}
1717	1726
1718		- /* As we bypass the pagecache we must now flush the inode so that
1719		- * we see all the changes from userspace... */
1720		- write_inode_now(inode, 1);
1721		- /* And now flush the block cache so that kernel sees the changes */
1722		- invalidate_bdev(sb->s_bdev);
	1727	+ if (!(dqopt->flags & DQUOT_QUOTA_SYS_FILE)) {
	1728	+ /* As we bypass the pagecache we must now flush the inode so
	1729	+ * that we see all the changes from userspace... */
	1730	+ write_inode_now(inode, 1);
	1731	+ /* And now flush the block cache so that kernel sees the
	1732	+ * changes */
	1733	+ invalidate_bdev(sb->s_bdev);
	1734	+ }
1723	1735	mutex_lock(&inode->i_mutex);
1724	1736	mutex_lock(&dqopt->dqonoff_mutex);
1725	1737	if (sb_has_quota_loaded(sb, type)) {
1726	1738	error = -EBUSY;
1727	1739	goto out_lock;
1728	1740	}
1729		- /* We don't want quota and atime on quota files (deadlocks possible)
1730		- * Also nobody should write to the file - we use special IO operations
1731		- * which ignore the immutable bit. */
1732		- down_write(&dqopt->dqptr_sem);
1733		- oldflags = inode->i_flags & (S_NOATIME \| S_IMMUTABLE \| S_NOQUOTA);
1734		- inode->i_flags \|= S_NOQUOTA \| S_NOATIME \| S_IMMUTABLE;
1735		- up_write(&dqopt->dqptr_sem);
1736		- sb->dq_op->drop(inode);
	1741	+
	1742	+ if (!(dqopt->flags & DQUOT_QUOTA_SYS_FILE)) {
	1743	+ /* We don't want quota and atime on quota files (deadlocks
	1744	+ * possible) Also nobody should write to the file - we use
	1745	+ * special IO operations which ignore the immutable bit. */
	1746	+ down_write(&dqopt->dqptr_sem);
	1747	+ oldflags = inode->i_flags & (S_NOATIME \| S_IMMUTABLE \| S_NOQUOTA);
	1748	+ inode->i_flags \|= S_NOQUOTA \| S_NOATIME \| S_IMMUTABLE;
	1749	+ up_write(&dqopt->dqptr_sem);
	1750	+ sb->dq_op->drop(inode);
	1751	+ }
1737	1752
1738	1753	error = -EIO;
1739	1754	dqopt->files[type] = igrab(inode);
...	...	@@ -160,6 +160,9 @@
160	160	int cnt;
161	161
162	162	sb->s_qcop->quota_sync(sb, type);
	163	+
	164	+ if (sb_dqopt(sb)->flags & DQUOT_QUOTA_SYS_FILE)
	165	+ return;
163	166	/* This is not very clever (and fast) but currently I don't know about
164	167	* any other simple way of getting quota data to disk and we must get
165	168	* them there for userspace to be visible... */
...	...	@@ -332,6 +332,13 @@
332	332	#define DQUOT_SUSPENDED (1 << _DQUOT_SUSPENDED)
333	333	#define DQUOT_STATE_FLAGS (DQUOT_USAGE_ENABLED \| DQUOT_LIMITS_ENABLED \| \
334	334	DQUOT_SUSPENDED)
	335	+/* Other quota flags */
	336	+#define DQUOT_QUOTA_SYS_FILE (1 << 6) /* Quota file is a special
	337	+ * system file and user cannot
	338	+ * touch it. Filesystem is
	339	+ * responsible for setting
	340	+ * S_NOQUOTA, S_NOATIME flags
	341	+ */
335	342
336	343	static inline unsigned int dquot_state_flag(unsigned int flags, int type)
337	344	{