Commit 2ec1f301 authored by Jan Kara's avatar Jan Kara
Browse files

quota: Make dquot_disable() work without quota inodes 



Quota on and quota off are protected by s_umount semaphore held in
exclusive mode since commit 7d6cd73d "quota: Hold s_umount in
exclusive mode when enabling / disabling quotas". This makes it
impossible for dquot_disable() to race with other enabling or disabling
of quotas. Simplify the cleanup done by dquot_disable() based on this
fact and also remove some stale comments. As a bonus this cleanup makes
dquot_disable() properly handle a case when there are no quota inodes.

Signed-off-by: default avatarJan Kara <jack@suse.cz>
parent 069a9166

fs/quota/dquot.c

+29 −44
Original line number Diff line number Diff line
@@ -2162,14 +2162,29 @@ int dquot_file_open(struct inode *inode, struct file *file) 
}

EXPORT_SYMBOL(dquot_file_open);



static void vfs_cleanup_quota_inode(struct super_block *sb, int type)

{

	struct quota_info *dqopt = sb_dqopt(sb);

	struct inode *inode = dqopt->files[type];



	if (!inode)

		return;

	if (!(dqopt->flags & DQUOT_QUOTA_SYS_FILE)) {

		inode_lock(inode);

		inode->i_flags &= ~S_NOQUOTA;

		inode_unlock(inode);

	}

	dqopt->files[type] = NULL;

	iput(inode);

}



/*

 * Turn quota off on a device. type == -1 ==> quotaoff for all types (umount)

 */

int dquot_disable(struct super_block *sb, int type, unsigned int flags)

{

	int cnt, ret = 0;

	int cnt;

	struct quota_info *dqopt = sb_dqopt(sb);

	struct inode *toputinode[MAXQUOTAS];



	/* s_umount should be held in exclusive mode */

	if (WARN_ON_ONCE(down_read_trylock(&sb->s_umount)))
@@ -2191,7 +2206,6 @@ int dquot_disable(struct super_block *sb, int type, unsigned int flags) 
		return 0;



	for (cnt = 0; cnt < MAXQUOTAS; cnt++) {

		toputinode[cnt] = NULL;

		if (type != -1 && cnt != type)

			continue;

		if (!sb_has_quota_loaded(sb, cnt))
@@ -2211,8 +2225,7 @@ int dquot_disable(struct super_block *sb, int type, unsigned int flags) 
				dqopt->flags &=	~dquot_state_flag(

							DQUOT_SUSPENDED, cnt);

				spin_unlock(&dq_state_lock);

				iput(dqopt->files[cnt]);

				dqopt->files[cnt] = NULL;

				vfs_cleanup_quota_inode(sb, cnt);

				continue;

			}

			spin_unlock(&dq_state_lock);
@@ -2234,10 +2247,6 @@ int dquot_disable(struct super_block *sb, int type, unsigned int flags) 
		if (dqopt->ops[cnt]->free_file_info)

			dqopt->ops[cnt]->free_file_info(sb, cnt);

		put_quota_format(dqopt->info[cnt].dqi_format);



		toputinode[cnt] = dqopt->files[cnt];

		if (!sb_has_quota_loaded(sb, cnt))

			dqopt->files[cnt] = NULL;

		dqopt->info[cnt].dqi_flags = 0;

		dqopt->info[cnt].dqi_igrace = 0;

		dqopt->info[cnt].dqi_bgrace = 0;
@@ -2259,32 +2268,22 @@ int dquot_disable(struct super_block *sb, int type, unsigned int flags) 
	 * must also discard the blockdev buffers so that we see the

	 * changes done by userspace on the next quotaon() */

	for (cnt = 0; cnt < MAXQUOTAS; cnt++)

		/* This can happen when suspending quotas on remount-ro... */

		if (toputinode[cnt] && !sb_has_quota_loaded(sb, cnt)) {

			inode_lock(toputinode[cnt]);

			toputinode[cnt]->i_flags &= ~S_NOQUOTA;

			truncate_inode_pages(&toputinode[cnt]->i_data, 0);

			inode_unlock(toputinode[cnt]);

			mark_inode_dirty_sync(toputinode[cnt]);

		if (!sb_has_quota_loaded(sb, cnt) && dqopt->files[cnt]) {

			inode_lock(dqopt->files[cnt]);

			truncate_inode_pages(&dqopt->files[cnt]->i_data, 0);

			inode_unlock(dqopt->files[cnt]);

		}

	if (sb->s_bdev)

		invalidate_bdev(sb->s_bdev);

put_inodes:

	/* We are done when suspending quotas */

	if (flags & DQUOT_SUSPENDED)

		return 0;



	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_

			 * function because another quotaon / quotaoff could

			 * change global state before we got here. We refuse

			 * to suspend quotas when there is pending delete on

			 * the quota file... */

			if (!(flags & DQUOT_SUSPENDED))

				iput(toputinode[cnt]);

			else if (!toputinode[cnt]->i_nlink)

				ret = -EBUSY;

		}

	return ret;

		if (!sb_has_quota_loaded(sb, cnt))

			vfs_cleanup_quota_inode(sb, cnt);

	return 0;

}

EXPORT_SYMBOL(dquot_disable);
@@ -2330,20 +2329,6 @@ static int vfs_setup_quota_inode(struct inode *inode, int type) 
	return 0;

}



static void vfs_cleanup_quota_inode(struct super_block *sb, int type)

{

	struct quota_info *dqopt = sb_dqopt(sb);

	struct inode *inode = dqopt->files[type];



	if (!(dqopt->flags & DQUOT_QUOTA_SYS_FILE)) {

		inode_lock(inode);

		inode->i_flags &= ~S_NOQUOTA;

		inode_unlock(inode);

	}

	dqopt->files[type] = NULL;

	iput(inode);

}



int dquot_load_quota_sb(struct super_block *sb, int type, int format_id,

	unsigned int flags)

{

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