5 files changed, 113 insertions, 22 deletions

diff --git a/fs/dquot.c b/fs/dquot.c
index fc26d1097d3c..dfba1623cccb 100644
--- a/fs/dquot.c
+++ b/fs/dquot.c
@@ -1449,31 +1449,43 @@ static inline void set_enable_flags(struct quota_info *dqopt, int type)
         switch (type) {
                 case USRQUOTA:
                         dqopt->flags |= DQUOT_USR_ENABLED;
+                        dqopt->flags &= ~DQUOT_USR_SUSPENDED;
                         break;
                 case GRPQUOTA:
                         dqopt->flags |= DQUOT_GRP_ENABLED;
+                        dqopt->flags &= ~DQUOT_GRP_SUSPENDED;
                         break;
         }
 }
 
-static inline void reset_enable_flags(struct quota_info *dqopt, int type)
+static inline void reset_enable_flags(struct quota_info *dqopt, int type,
+                                      int remount)
 {
         switch (type) {
                 case USRQUOTA:
                         dqopt->flags &= ~DQUOT_USR_ENABLED;
+                        if (remount)
+                                dqopt->flags |= DQUOT_USR_SUSPENDED;
+                        else
+                                dqopt->flags &= ~DQUOT_USR_SUSPENDED;
                         break;
                 case GRPQUOTA:
                         dqopt->flags &= ~DQUOT_GRP_ENABLED;
+                        if (remount)
+                                dqopt->flags |= DQUOT_GRP_SUSPENDED;
+                        else
+                                dqopt->flags &= ~DQUOT_GRP_SUSPENDED;
                         break;
         }
 }
 
+
 /*
  * Turn quota off on a device. type == -1 ==> quotaoff for all types (umount)
  */
-int vfs_quota_off(struct super_block *sb, int type)
+int vfs_quota_off(struct super_block *sb, int type, int remount)
 {
-        int cnt;
+        int cnt, ret = 0;
         struct quota_info *dqopt = sb_dqopt(sb);
         struct inode *toputinode[MAXQUOTAS];
 
@@ -1483,9 +1495,17 @@ int vfs_quota_off(struct super_block *sb, int type)
                 toputinode[cnt] = NULL;
                 if (type != -1 && cnt != type)
                         continue;
+                /* If we keep inodes of quota files after remount and quotaoff
+                 * is called, drop kept inodes. */
+                if (!remount && sb_has_quota_suspended(sb, cnt)) {
+                        iput(dqopt->files[cnt]);
+                        dqopt->files[cnt] = NULL;
+                        reset_enable_flags(dqopt, cnt, 0);
+                        continue;
+                }
                 if (!sb_has_quota_enabled(sb, cnt))
                         continue;
-                reset_enable_flags(dqopt, cnt);
+                reset_enable_flags(dqopt, cnt, remount);
 
                 /* Note: these are blocking operations */
                 drop_dquot_ref(sb, cnt);
@@ -1501,7 +1521,8 @@ int vfs_quota_off(struct super_block *sb, int type)
                 put_quota_format(dqopt->info[cnt].dqi_format);
 
                 toputinode[cnt] = dqopt->files[cnt];
-                dqopt->files[cnt] = NULL;
+                if (!remount)
+                        dqopt->files[cnt] = NULL;
                 dqopt->info[cnt].dqi_flags = 0;
                 dqopt->info[cnt].dqi_igrace = 0;
                 dqopt->info[cnt].dqi_bgrace = 0;
@@ -1531,12 +1552,19 @@ int vfs_quota_off(struct super_block *sb, int type)
                                 mutex_unlock(&toputinode[cnt]->i_mutex);
                                 mark_inode_dirty(toputinode[cnt]);
                         }
-                        iput(toputinode[cnt]);
                         mutex_unlock(&dqopt->dqonoff_mutex);
+                        /* On remount RO, we keep the inode pointer so that we
+                         * can reenable quota on the subsequent remount RW.
+                         * But we have better not keep inode pointer when there
+                         * is pending delete on the quota file... */
+                        if (!remount)
+                                iput(toputinode[cnt]);
+                        else if (!toputinode[cnt]->i_nlink)
+                                ret = -EBUSY;
                 }
         if (sb->s_bdev)
                 invalidate_bdev(sb->s_bdev);
-        return 0;
+        return ret;
 }
 
 /*
@@ -1574,7 +1602,8 @@ static int vfs_quota_on_inode(struct inode *inode, int type, int format_id)
         invalidate_bdev(sb->s_bdev);
         mutex_lock(&inode->i_mutex);
         mutex_lock(&dqopt->dqonoff_mutex);
-        if (sb_has_quota_enabled(sb, type)) {
+        if (sb_has_quota_enabled(sb, type) ||
+                        sb_has_quota_suspended(sb, type)) {
                 error = -EBUSY;
                 goto out_lock;
         }
@@ -1597,6 +1626,7 @@ static int vfs_quota_on_inode(struct inode *inode, int type, int format_id)
 
         dqopt->ops[type] = fmt->qf_ops;
         dqopt->info[type].dqi_format = fmt;
+        dqopt->info[type].dqi_fmt_id = format_id;
         INIT_LIST_HEAD(&dqopt->info[type].dqi_dirty_list);
         mutex_lock(&dqopt->dqio_mutex);
         if ((error = dqopt->ops[type]->read_file_info(sb, type)) < 0) {
@@ -1632,12 +1662,41 @@ out_fmt:
         return error; 
 }
 
+/* Reenable quotas on remount RW */
+static int vfs_quota_on_remount(struct super_block *sb, int type)
+{
+        struct quota_info *dqopt = sb_dqopt(sb);
+        struct inode *inode;
+        int ret;
+
+        mutex_lock(&dqopt->dqonoff_mutex);
+        if (!sb_has_quota_suspended(sb, type)) {
+                mutex_unlock(&dqopt->dqonoff_mutex);
+                return 0;
+        }
+        BUG_ON(sb_has_quota_enabled(sb, type));
+
+        inode = dqopt->files[type];
+        dqopt->files[type] = NULL;
+        reset_enable_flags(dqopt, type, 0);
+        mutex_unlock(&dqopt->dqonoff_mutex);
+
+        ret = vfs_quota_on_inode(inode, type, dqopt->info[type].dqi_fmt_id);
+        iput(inode);
+
+        return ret;
+}
+
 /* Actual function called from quotactl() */
-int vfs_quota_on(struct super_block *sb, int type, int format_id, char *path)
+int vfs_quota_on(struct super_block *sb, int type, int format_id, char *path,
+                 int remount)
 {
         struct nameidata nd;
         int error;
 
+        if (remount)
+                return vfs_quota_on_remount(sb, type);
+
         error = path_lookup(path, LOOKUP_FOLLOW, &nd);
         if (error < 0)
                 return error;
diff --git a/fs/quota.c b/fs/quota.c
index 84f28dd72116..db1cc9f3c7aa 100644
--- a/fs/quota.c
+++ b/fs/quota.c
@@ -69,7 +69,6 @@ static int generic_quotactl_valid(struct super_block *sb, int type, int cmd, qid
         switch (cmd) {
                 case Q_GETFMT:
                 case Q_GETINFO:
-                case Q_QUOTAOFF:
                 case Q_SETINFO:
                 case Q_SETQUOTA:
                 case Q_GETQUOTA:
@@ -229,12 +228,12 @@ static int do_quotactl(struct super_block *sb, int type, int cmd, qid_t id, void
 
                         if (IS_ERR(pathname = getname(addr)))
                                 return PTR_ERR(pathname);
-                        ret = sb->s_qcop->quota_on(sb, type, id, pathname);
+                        ret = sb->s_qcop->quota_on(sb, type, id, pathname, 0);
                         putname(pathname);
                         return ret;
                 }
                 case Q_QUOTAOFF:
-                        return sb->s_qcop->quota_off(sb, type);
+                        return sb->s_qcop->quota_off(sb, type, 0);
 
                 case Q_GETFMT: {
                         __u32 fmt;
diff --git a/fs/super.c b/fs/super.c
index 4798350b2bc9..a5a4aca7e22f 100644
--- a/fs/super.c
+++ b/fs/super.c
@@ -179,7 +179,7 @@ void deactivate_super(struct super_block *s)
         if (atomic_dec_and_lock(&s->s_active, &sb_lock)) {
                 s->s_count -= S_BIAS-1;
                 spin_unlock(&sb_lock);
-                DQUOT_OFF(s);
+                DQUOT_OFF(s, 0);
                 down_write(&s->s_umount);
                 fs->kill_sb(s);
                 put_filesystem(fs);
@@ -608,6 +608,7 @@ retry:
 int do_remount_sb(struct super_block *sb, int flags, void *data, int force)
 {
         int retval;
+        int remount_rw;
         
 #ifdef CONFIG_BLOCK
         if (!(flags & MS_RDONLY) && bdev_read_only(sb->s_bdev))
@@ -625,8 +626,11 @@ int do_remount_sb(struct super_block *sb, int flags, void *data, int force)
                         mark_files_ro(sb);
                 else if (!fs_may_remount_ro(sb))
                         return -EBUSY;
-                DQUOT_OFF(sb);
+                retval = DQUOT_OFF(sb, 1);
+                if (retval < 0 && retval != -ENOSYS)
+                        return -EBUSY;
         }
+        remount_rw = !(flags & MS_RDONLY) && (sb->s_flags & MS_RDONLY);
 
         if (sb->s_op->remount_fs) {
                 lock_super(sb);
@@ -636,6 +640,8 @@ int do_remount_sb(struct super_block *sb, int flags, void *data, int force)
                         return retval;
         }
         sb->s_flags = (sb->s_flags & ~MS_RMT_MASK) | (flags & MS_RMT_MASK);
+        if (remount_rw)
+                DQUOT_ON_REMOUNT(sb);
         return 0;
 }
 
diff --git a/include/linux/quota.h b/include/linux/quota.h
index 48556b039b1c..52e49dce6584 100644
--- a/include/linux/quota.h
+++ b/include/linux/quota.h
@@ -202,6 +202,8 @@ struct quota_format_type;
 
 struct mem_dqinfo {
         struct quota_format_type *dqi_format;
+        int dqi_fmt_id;         /* Id of the dqi_format - used when turning
+                                 * quotas on after remount RW */
         struct list_head dqi_dirty_list;        /* List of dirty dquots */
         unsigned long dqi_flags;
         unsigned int dqi_bgrace;
@@ -298,8 +300,8 @@ struct dquot_operations {
 
 /* Operations handling requests from userspace */
 struct quotactl_ops {
-        int (*quota_on)(struct super_block *, int, int, char *);
-        int (*quota_off)(struct super_block *, int);
+        int (*quota_on)(struct super_block *, int, int, char *, int);
+        int (*quota_off)(struct super_block *, int, int);
         int (*quota_sync)(struct super_block *, int);
         int (*get_info)(struct super_block *, int, struct if_dqinfo *);
         int (*set_info)(struct super_block *, int, struct if_dqinfo *);
@@ -320,6 +322,10 @@ struct quota_format_type {
 
 #define DQUOT_USR_ENABLED       0x01            /* User diskquotas enabled */
 #define DQUOT_GRP_ENABLED       0x02            /* Group diskquotas enabled */
+#define DQUOT_USR_SUSPENDED     0x04            /* User diskquotas are off, but
+                                                 * we have necessary info in
+                                                 * memory to turn them on */
+#define DQUOT_GRP_SUSPENDED     0x08            /* The same for group quotas */
 
 struct quota_info {
         unsigned int flags;                     /* Flags for diskquotas on this device */
@@ -337,6 +343,10 @@ struct quota_info {
 #define sb_any_quota_enabled(sb) (sb_has_quota_enabled(sb, USRQUOTA) | \
                                   sb_has_quota_enabled(sb, GRPQUOTA))
 
+#define sb_has_quota_suspended(sb, type) \
+        ((type) == USRQUOTA ? (sb_dqopt(sb)->flags & DQUOT_USR_SUSPENDED) : \
+                              (sb_dqopt(sb)->flags & DQUOT_GRP_SUSPENDED))
+
 int register_quota_format(struct quota_format_type *fmt);
 void unregister_quota_format(struct quota_format_type *fmt);
 
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)
 {