[PATCH 06/11] quota: Add ->sysquota_{on, off} callbacks for VFS quotas

Jan Kara
2014-11-11T21:04:48Z

Add functions which translate ->sysquota_on / ->sysquota_off calls into
appropriate changes in VFS quota. This will enable filesystems
supporting VFS quota files in system inodes to be controlled via
Q_XQUOTA[ON|OFF] quotactls for better userspace compatibility.

Signed-off-by: Jan Kara <jack@suse.cz>
---
fs/quota/dquot.c | 82 ++++++++++++++++++++++++++++++++++++++++++++++++
include/linux/quotaops.h | 2 ++
2 files changed, 84 insertions(+)

diff --git a/fs/quota/dquot.c b/fs/quota/dquot.c
index 6b4527216a7f..b7359c9da61e 100644
--- a/fs/quota/dquot.c
+++ b/fs/quota/dquot.c
@@ -2380,6 +2380,88 @@ out:
}
EXPORT_SYMBOL(dquot_quota_on_mount);

+int dquot_sysquota_on(struct super_block *sb, unsigned int flags)
+{
+ int ret;
+ int type;
+ struct quota_info *dqopt = sb_dqopt(sb);
+
+ if (!(dqopt->flags & DQUOT_QUOTA_SYS_FILE))
+ return -ENOSYS;
+ /* Accounting cannot be turned on while fs is mounted */
+ flags &= ~(FS_QUOTA_UDQ_ACCT | FS_QUOTA_GDQ_ACCT | FS_QUOTA_PDQ_ACCT);
+ if (!flags)
+ return -EINVAL;
+ for (type = 0; type < MAXQUOTAS; type++) {
+ if (!(flags & qtype_limit_flag(type)))
+ continue;
+ /* Can't enforce without accounting */
+ if (!sb_has_quota_usage_enabled(sb, type))
+ return -EINVAL;
+ ret = dquot_enable(dqopt->files[type], type,
+ dqopt->info[type].dqi_fmt_id,
+ DQUOT_LIMITS_ENABLED);
+ if (ret < 0)
+ goto out_err;
+ }
+ return 0;
+out_err:
+ /* Backout enforcement enablement we already did */
+ for (type--; type >= 0; type--) {
+ if (flags & qtype_limit_flag(type))
+ dquot_disable(sb, type, DQUOT_LIMITS_ENABLED);
+ }
+ /* Error code translation for better compatibility with XFS */
+ if (ret == -EBUSY)
+ ret = -EEXIST;
+ return ret;
+}
+EXPORT_SYMBOL(dquot_sysquota_on);
+
+int dquot_sysquota_off(struct super_block *sb, unsigned int flags)
+{
+ int ret;
+ int type;
+ struct quota_info *dqopt = sb_dqopt(sb);
+
+ if (!(dqopt->flags & DQUOT_QUOTA_SYS_FILE))
+ return -ENOSYS;
+ /*
+ * We don't support turning off accounting via quotactl. In principle
+ * quota infrastructure can do this but filesystems don't expect
+ * userspace to be able to do it.
+ */
+ if (flags &
+ (FS_QUOTA_UDQ_ACCT | FS_QUOTA_GDQ_ACCT | FS_QUOTA_PDQ_ACCT))
+ return -EOPNOTSUPP;
+
+ /* Filter out limits not enabled */
+ for (type = 0; type < MAXQUOTAS; type++)
+ if (!sb_has_quota_limits_enabled(sb, type))
+ flags &= ~qtype_limit_flag(type);
+ /* Nothing left? */
+ if (!flags)
+ return -EEXIST;
+ for (type = 0; type < MAXQUOTAS; type++) {
+ if (flags & qtype_limit_flag(type)) {
+ ret = dquot_disable(sb, type, DQUOT_LIMITS_ENABLED);
+ if (ret < 0)
+ goto out_err;
+ }
+ }
+ return 0;
+out_err:
+ /* Backout enforcement disabling we already did */
+ for (type--; type >= 0; type--) {
+ if (flags & qtype_limit_flag(type))
+ dquot_enable(dqopt->files[type], type,
+ dqopt->info[type].dqi_fmt_id,
+ DQUOT_LIMITS_ENABLED);
+ }
+ return ret;
+}
+EXPORT_SYMBOL(dquot_sysquota_off);
+
static inline qsize_t qbtos(qsize_t blocks)
{
return blocks << QIF_DQBLKSIZE_BITS;
diff --git a/include/linux/quotaops.h b/include/linux/quotaops.h
index 5947a9e54862..6f5dc7e397a7 100644
--- a/include/linux/quotaops.h
+++ b/include/linux/quotaops.h
@@ -93,6 +93,8 @@ int dquot_quota_on(struct super_block *sb, int type, int format_id,
int dquot_quota_on_mount(struct super_block *sb, char *qf_name,
int format_id, int type);
int dquot_quota_off(struct super_block *sb, int type);
+int dquot_sysquota_on(struct super_block *sb, unsigned int flags);
+int dquot_sysquota_off(struct super_block *sb, unsigned int flags);
int dquot_writeback_dquots(struct super_block *sb, int type);
int dquot_quota_sync(struct super_block *sb, int type);
int dquot_get_dqinfo(struct super_block *sb, int type, struct if_dqinfo *ii);