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quota: Introduce DQUOT_QUOTA_SYS_FILE flag

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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>
This commit is contained in:
Jan Kara 2008-09-30 17:53:37 +02:00 committed by Mark Fasheh
parent dcb30695f2
commit ca785ec66b
3 changed files with 40 additions and 15 deletions
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45
fs/dquot.c
View File

@ -1631,6 +1631,11 @@ int vfs_quota_disable(struct super_block *sb, int type, unsigned int flags)
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 @@ int vfs_quota_disable(struct super_block *sb, int type, unsigned int flags)
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 @@ int vfs_quota_disable(struct super_block *sb, int type, unsigned int flags)
else if (!toputinode[cnt]->i_nlink)
ret = -EBUSY;
}
if (sb->s_bdev)
invalidate_bdev(sb->s_bdev);
return ret;
}
@ -1715,25 +1724,31 @@ static int vfs_load_quota_inode(struct inode *inode, int type, int format_id,
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);

3
fs/quota.c
View File

@ -160,6 +160,9 @@ static void quota_sync_sb(struct super_block *sb, int type)
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... */

7
include/linux/quota.h
View File

@ -332,6 +332,13 @@ enum {
#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)
{