quota: Split dquot_quota_sync() to writeback and cache flushing part

Split off part of dquot_quota_sync() which writes dquots into a quota file
to a separate function. In the next patch we will use the function from
filesystems and we do not want to abuse ->quota_sync quotactl callback more
than necessary.

Acked-by: Steven Whitehouse <swhiteho@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

2 files changed, 23 insertions, 5 deletions

diff --git a/fs/quota/dquot.c b/fs/quota/dquot.c
index 10cbe841cb7..d679fc48ef2 100644
--- a/fs/quota/dquot.c
+++ b/fs/quota/dquot.c
@@ -595,12 +595,14 @@ out:
 }
 EXPORT_SYMBOL(dquot_scan_active);
 
-int dquot_quota_sync(struct super_block *sb, int type, int wait)
+/* Write all dquot structures to quota files */
+int dquot_writeback_dquots(struct super_block *sb, int type)
 {
         struct list_head *dirty;
         struct dquot *dquot;
         struct quota_info *dqopt = sb_dqopt(sb);
         int cnt;
+        int err, ret = 0;
 
         mutex_lock(&dqopt->dqonoff_mutex);
         for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
@@ -624,7 +626,9 @@ int dquot_quota_sync(struct super_block *sb, int type, int wait)
                         atomic_inc(&dquot->dq_count);
                         spin_unlock(&dq_list_lock);
                         dqstats_inc(DQST_LOOKUPS);
-                        sb->dq_op->write_dquot(dquot);
+                        err = sb->dq_op->write_dquot(dquot);
+                        if (!ret && err)
+                                err = ret;
                         dqput(dquot);
                         spin_lock(&dq_list_lock);
                 }
@@ -638,7 +642,21 @@ int dquot_quota_sync(struct super_block *sb, int type, int wait)
         dqstats_inc(DQST_SYNCS);
         mutex_unlock(&dqopt->dqonoff_mutex);
 
-        if (!wait || (dqopt->flags & DQUOT_QUOTA_SYS_FILE))
+        return ret;
+}
+EXPORT_SYMBOL(dquot_writeback_dquots);
+
+/* Write all dquot structures to disk and make them visible from userspace */
+int dquot_quota_sync(struct super_block *sb, int type)
+{
+        struct quota_info *dqopt = sb_dqopt(sb);
+        int cnt;
+        int ret;
+
+        ret = dquot_writeback_dquots(sb, type);
+        if (ret)
+                return ret;
+        if (dqopt->flags & DQUOT_QUOTA_SYS_FILE)
                 return 0;
 
         /* This is not very clever (and fast) but currently I don't know about
diff --git a/fs/quota/quota.c b/fs/quota/quota.c
index 9a391204ca2..c659f92298d 100644
--- a/fs/quota/quota.c
+++ b/fs/quota/quota.c
@@ -47,7 +47,7 @@ static int check_quotactl_permission(struct super_block *sb, int type, int cmd,
 static void quota_sync_one(struct super_block *sb, void *arg)
 {
         if (sb->s_qcop && sb->s_qcop->quota_sync)
-                sb->s_qcop->quota_sync(sb, *(int *)arg, 1);
+                sb->s_qcop->quota_sync(sb, *(int *)arg);
 }
 
 static int quota_sync_all(int type)
@@ -270,7 +270,7 @@ static int do_quotactl(struct super_block *sb, int type, int cmd, qid_t id,
         case Q_SYNC:
                 if (!sb->s_qcop->quota_sync)
                         return -ENOSYS;
-                return sb->s_qcop->quota_sync(sb, type, 1);
+                return sb->s_qcop->quota_sync(sb, type);
         case Q_XQUOTAON:
         case Q_XQUOTAOFF:
         case Q_XQUOTARM: