quota: quota core changes for quotaon on remount

Currently, we just turn quotas off on remount of filesystem to read-only
state.  The patch below adds necessary framework so that we can turn quotas
off on remount RO but we are able to automatically reenable them again when
filesystem is remounted to RW state.  All we need to do is to keep references
to inodes of quota files when remounting RO and using these references to
reenable quotas when remounting RW.

Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 23 insertions, 6 deletions

diff --git a/include/linux/quotaops.h b/include/linux/quotaops.h
index 1aac25511f07..c97c8f3fa6ee 100644
--- a/include/linux/quotaops.h
+++ b/include/linux/quotaops.h
@@ -37,10 +37,11 @@ extern int dquot_release(struct dquot *dquot);
 extern int dquot_commit_info(struct super_block *sb, int type);
 extern int dquot_mark_dquot_dirty(struct dquot *dquot);
 
-extern int vfs_quota_on(struct super_block *sb, int type, int format_id, char *path);
+extern int vfs_quota_on(struct super_block *sb, int type, int format_id,
+                char *path, int remount);
 extern int vfs_quota_on_mount(struct super_block *sb, char *qf_name,
                 int format_id, int type);
-extern int vfs_quota_off(struct super_block *sb, int type);
+extern int vfs_quota_off(struct super_block *sb, int type, int remount);
 extern int vfs_quota_sync(struct super_block *sb, int type);
 extern int vfs_get_dqinfo(struct super_block *sb, int type, struct if_dqinfo *ii);
 extern int vfs_set_dqinfo(struct super_block *sb, int type, struct if_dqinfo *ii);
@@ -175,12 +176,27 @@ static inline void DQUOT_SYNC(struct super_block *sb)
         sync_dquots(sb, -1);
 }
 
-static inline int DQUOT_OFF(struct super_block *sb)
+static inline int DQUOT_OFF(struct super_block *sb, int remount)
 {
         int ret = -ENOSYS;
 
-        if (sb_any_quota_enabled(sb) && sb->s_qcop && sb->s_qcop->quota_off)
-                ret = sb->s_qcop->quota_off(sb, -1);
+        if (sb->s_qcop && sb->s_qcop->quota_off)
+                ret = sb->s_qcop->quota_off(sb, -1, remount);
+        return ret;
+}
+
+static inline int DQUOT_ON_REMOUNT(struct super_block *sb)
+{
+        int cnt;
+        int ret = 0, err;
+
+        if (!sb->s_qcop || !sb->s_qcop->quota_on)
+                return -ENOSYS;
+        for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
+                err = sb->s_qcop->quota_on(sb, cnt, 0, NULL, 1);
+                if (err < 0 && !ret)
+                        ret = err;
+        }
         return ret;
 }
 
@@ -196,7 +212,8 @@ static inline int DQUOT_OFF(struct super_block *sb)
 #define DQUOT_ALLOC_INODE(inode)                (0)
 #define DQUOT_FREE_INODE(inode)                 do { } while(0)
 #define DQUOT_SYNC(sb)                          do { } while(0)
-#define DQUOT_OFF(sb)                           (0)
+#define DQUOT_OFF(sb, remount)                  (0)
+#define DQUOT_ON_REMOUNT(sb)                    (0)
 #define DQUOT_TRANSFER(inode, iattr)            (0)
 static inline int DQUOT_PREALLOC_SPACE_NODIRTY(struct inode *inode, qsize_t nr)
 {