The complex patch with which MohammadAG had his success
[h-e-n] / fs / dquot.c
index fc26d10..5e95261 100644 (file)
@@ -9,8 +9,6 @@
  * implementation is based on one of the several variants of the LINUX
  * inode-subsystem with added complexity of the diskquota system.
  * 
- * Version: $Id: dquot.c,v 6.3 1996/11/17 18:35:34 mvw Exp mvw $
- * 
  * Author:     Marco van Wieringen <mvw@planets.elm.net>
  *
  * Fixes:   Dmitry Gorodchanin <pgmdsg@ibi.com>, 11 Feb 96
@@ -562,6 +560,8 @@ static struct shrinker dqcache_shrinker = {
  */
 static void dqput(struct dquot *dquot)
 {
+       int ret;
+
        if (!dquot)
                return;
 #ifdef __DQUOT_PARANOIA
@@ -594,7 +594,19 @@ we_slept:
        if (test_bit(DQ_ACTIVE_B, &dquot->dq_flags) && dquot_dirty(dquot)) {
                spin_unlock(&dq_list_lock);
                /* Commit dquot before releasing */
-               dquot->dq_sb->dq_op->write_dquot(dquot);
+               ret = dquot->dq_sb->dq_op->write_dquot(dquot);
+               if (ret < 0) {
+                       printk(KERN_ERR "VFS: cannot write quota structure on "
+                               "device %s (error %d). Quota may get out of "
+                               "sync!\n", dquot->dq_sb->s_id, ret);
+                       /*
+                        * We clear dirty bit anyway, so that we avoid
+                        * infinite loop here
+                        */
+                       spin_lock(&dq_list_lock);
+                       clear_dquot_dirty(dquot);
+                       spin_unlock(&dq_list_lock);
+               }
                goto we_slept;
        }
        /* Clear flag in case dquot was inactive (something bad happened) */
@@ -875,13 +887,15 @@ static void print_warning(struct dquot *dquot, const int warntype)
        char *msg = NULL;
        struct tty_struct *tty;
 
-       if (!need_print_warning(dquot))
+       if (warntype == QUOTA_NL_IHARDBELOW ||
+           warntype == QUOTA_NL_ISOFTBELOW ||
+           warntype == QUOTA_NL_BHARDBELOW ||
+           warntype == QUOTA_NL_BSOFTBELOW || !need_print_warning(dquot))
                return;
 
-       mutex_lock(&tty_mutex);
        tty = get_current_tty();
        if (!tty)
-               goto out_lock;
+               return;
        tty_write_message(tty, dquot->dq_sb->s_id);
        if (warntype == QUOTA_NL_ISOFTWARN || warntype == QUOTA_NL_BSOFTWARN)
                tty_write_message(tty, ": warning, ");
@@ -909,8 +923,7 @@ static void print_warning(struct dquot *dquot, const int warntype)
                        break;
        }
        tty_write_message(tty, msg);
-out_lock:
-       mutex_unlock(&tty_mutex);
+       tty_kref_put(tty);
 }
 #endif
 
@@ -1083,6 +1096,35 @@ static int check_bdq(struct dquot *dquot, qsize_t space, int prealloc, char *war
        return QUOTA_OK;
 }
 
+static int info_idq_free(struct dquot *dquot, ulong inodes)
+{
+       if (test_bit(DQ_FAKE_B, &dquot->dq_flags) ||
+           dquot->dq_dqb.dqb_curinodes <= dquot->dq_dqb.dqb_isoftlimit)
+               return QUOTA_NL_NOWARN;
+
+       if (dquot->dq_dqb.dqb_curinodes - inodes <= dquot->dq_dqb.dqb_isoftlimit)
+               return QUOTA_NL_ISOFTBELOW;
+       if (dquot->dq_dqb.dqb_curinodes >= dquot->dq_dqb.dqb_ihardlimit &&
+           dquot->dq_dqb.dqb_curinodes - inodes < dquot->dq_dqb.dqb_ihardlimit)
+               return QUOTA_NL_IHARDBELOW;
+       return QUOTA_NL_NOWARN;
+}
+
+static int info_bdq_free(struct dquot *dquot, qsize_t space)
+{
+       if (test_bit(DQ_FAKE_B, &dquot->dq_flags) ||
+           toqb(dquot->dq_dqb.dqb_curspace) <= dquot->dq_dqb.dqb_bsoftlimit)
+               return QUOTA_NL_NOWARN;
+
+       if (toqb(dquot->dq_dqb.dqb_curspace - space) <=
+           dquot->dq_dqb.dqb_bsoftlimit)
+               return QUOTA_NL_BSOFTBELOW;
+       if (toqb(dquot->dq_dqb.dqb_curspace) >= dquot->dq_dqb.dqb_bhardlimit &&
+           toqb(dquot->dq_dqb.dqb_curspace - space) <
+                                               dquot->dq_dqb.dqb_bhardlimit)
+               return QUOTA_NL_BHARDBELOW;
+       return QUOTA_NL_NOWARN;
+}
 /*
  *     Initialize quota pointers in inode
  *     Transaction must be started at entry
@@ -1139,6 +1181,28 @@ int dquot_drop(struct inode *inode)
        return 0;
 }
 
+/* Wrapper to remove references to quota structures from inode */
+void vfs_dq_drop(struct inode *inode)
+{
+       /* Here we can get arbitrary inode from clear_inode() so we have
+        * to be careful. OTOH we don't need locking as quota operations
+        * are allowed to change only at mount time */
+       if (!IS_NOQUOTA(inode) && inode->i_sb && inode->i_sb->dq_op
+           && inode->i_sb->dq_op->drop) {
+               int cnt;
+               /* Test before calling to rule out calls from proc and such
+                 * where we are not allowed to block. Note that this is
+                * actually reliable test even without the lock - the caller
+                * must assure that nobody can come after the DQUOT_DROP and
+                * add quota pointers back anyway */
+               for (cnt = 0; cnt < MAXQUOTAS; cnt++)
+                       if (inode->i_dquot[cnt] != NODQUOT)
+                               break;
+               if (cnt < MAXQUOTAS)
+                       inode->i_sb->dq_op->drop(inode);
+       }
+}
+
 /*
  * Following four functions update i_blocks+i_bytes fields and
  * quota information (together with appropriate checks)
@@ -1248,6 +1312,7 @@ warn_put_all:
 int dquot_free_space(struct inode *inode, qsize_t number)
 {
        unsigned int cnt;
+       char warntype[MAXQUOTAS];
 
        /* First test before acquiring mutex - solves deadlocks when we
          * re-enter the quota code and are already holding the mutex */
@@ -1256,6 +1321,7 @@ out_sub:
                inode_sub_bytes(inode, number);
                return QUOTA_OK;
        }
+
        down_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
        /* Now recheck reliably when holding dqptr_sem */
        if (IS_NOQUOTA(inode)) {
@@ -1266,6 +1332,7 @@ out_sub:
        for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
                if (inode->i_dquot[cnt] == NODQUOT)
                        continue;
+               warntype[cnt] = info_bdq_free(inode->i_dquot[cnt], number);
                dquot_decr_space(inode->i_dquot[cnt], number);
        }
        inode_sub_bytes(inode, number);
@@ -1274,6 +1341,7 @@ out_sub:
        for (cnt = 0; cnt < MAXQUOTAS; cnt++)
                if (inode->i_dquot[cnt])
                        mark_dquot_dirty(inode->i_dquot[cnt]);
+       flush_warnings(inode->i_dquot, warntype);
        up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
        return QUOTA_OK;
 }
@@ -1284,11 +1352,13 @@ out_sub:
 int dquot_free_inode(const struct inode *inode, unsigned long number)
 {
        unsigned int cnt;
+       char warntype[MAXQUOTAS];
 
        /* First test before acquiring mutex - solves deadlocks when we
          * re-enter the quota code and are already holding the mutex */
        if (IS_NOQUOTA(inode))
                return QUOTA_OK;
+
        down_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
        /* Now recheck reliably when holding dqptr_sem */
        if (IS_NOQUOTA(inode)) {
@@ -1299,6 +1369,7 @@ int dquot_free_inode(const struct inode *inode, unsigned long number)
        for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
                if (inode->i_dquot[cnt] == NODQUOT)
                        continue;
+               warntype[cnt] = info_idq_free(inode->i_dquot[cnt], number);
                dquot_decr_inodes(inode->i_dquot[cnt], number);
        }
        spin_unlock(&dq_data_lock);
@@ -1306,6 +1377,7 @@ int dquot_free_inode(const struct inode *inode, unsigned long number)
        for (cnt = 0; cnt < MAXQUOTAS; cnt++)
                if (inode->i_dquot[cnt])
                        mark_dquot_dirty(inode->i_dquot[cnt]);
+       flush_warnings(inode->i_dquot, warntype);
        up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
        return QUOTA_OK;
 }
@@ -1323,7 +1395,8 @@ int dquot_transfer(struct inode *inode, struct iattr *iattr)
        struct dquot *transfer_to[MAXQUOTAS];
        int cnt, ret = NO_QUOTA, chuid = (iattr->ia_valid & ATTR_UID) && inode->i_uid != iattr->ia_uid,
            chgid = (iattr->ia_valid & ATTR_GID) && inode->i_gid != iattr->ia_gid;
-       char warntype[MAXQUOTAS];
+       char warntype_to[MAXQUOTAS];
+       char warntype_from_inodes[MAXQUOTAS], warntype_from_space[MAXQUOTAS];
 
        /* First test before acquiring mutex - solves deadlocks when we
          * re-enter the quota code and are already holding the mutex */
@@ -1332,7 +1405,7 @@ int dquot_transfer(struct inode *inode, struct iattr *iattr)
        /* Clear the arrays */
        for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
                transfer_to[cnt] = transfer_from[cnt] = NODQUOT;
-               warntype[cnt] = QUOTA_NL_NOWARN;
+               warntype_to[cnt] = QUOTA_NL_NOWARN;
        }
        down_write(&sb_dqopt(inode->i_sb)->dqptr_sem);
        /* Now recheck reliably when holding dqptr_sem */
@@ -1364,8 +1437,9 @@ int dquot_transfer(struct inode *inode, struct iattr *iattr)
                if (transfer_to[cnt] == NODQUOT)
                        continue;
                transfer_from[cnt] = inode->i_dquot[cnt];
-               if (check_idq(transfer_to[cnt], 1, warntype+cnt) == NO_QUOTA ||
-                   check_bdq(transfer_to[cnt], space, 0, warntype+cnt) == NO_QUOTA)
+               if (check_idq(transfer_to[cnt], 1, warntype_to + cnt) ==
+                   NO_QUOTA || check_bdq(transfer_to[cnt], space, 0,
+                   warntype_to + cnt) == NO_QUOTA)
                        goto warn_put_all;
        }
 
@@ -1381,6 +1455,10 @@ int dquot_transfer(struct inode *inode, struct iattr *iattr)
 
                /* Due to IO error we might not have transfer_from[] structure */
                if (transfer_from[cnt]) {
+                       warntype_from_inodes[cnt] =
+                               info_idq_free(transfer_from[cnt], 1);
+                       warntype_from_space[cnt] =
+                               info_bdq_free(transfer_from[cnt], space);
                        dquot_decr_inodes(transfer_from[cnt], 1);
                        dquot_decr_space(transfer_from[cnt], space);
                }
@@ -1400,7 +1478,9 @@ warn_put_all:
                if (transfer_to[cnt])
                        mark_dquot_dirty(transfer_to[cnt]);
        }
-       flush_warnings(transfer_to, warntype);
+       flush_warnings(transfer_to, warntype_to);
+       flush_warnings(transfer_from, warntype_from_inodes);
+       flush_warnings(transfer_from, warntype_from_space);
        
        for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
                if (ret == QUOTA_OK && transfer_from[cnt] != NODQUOT)
@@ -1412,6 +1492,18 @@ warn_put_all:
        return ret;
 }
 
+/* Wrapper for transferring ownership of an inode */
+int vfs_dq_transfer(struct inode *inode, struct iattr *iattr)
+{
+       if (sb_any_quota_enabled(inode->i_sb) && !IS_NOQUOTA(inode)) {
+               vfs_dq_init(inode);
+               if (inode->i_sb->dq_op->transfer(inode, iattr) == NO_QUOTA)
+                       return 1;
+       }
+       return 0;
+}
+
+
 /*
  * Write info of quota file to disk
  */
@@ -1449,43 +1541,73 @@ 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];
 
        /* We need to serialize quota_off() for device */
        mutex_lock(&dqopt->dqonoff_mutex);
+
+       /*
+        * Skip everything if there's nothing to do. We have to do this because
+        * sometimes we are called when fill_super() failed and calling
+        * sync_fs() in such cases does no good.
+        */
+       if (!sb_any_quota_enabled(sb) && !sb_any_quota_suspended(sb)) {
+               mutex_unlock(&dqopt->dqonoff_mutex);
+               return 0;
+       }
        for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
                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 +1623,8 @@ 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 +1654,19 @@ 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 +1704,8 @@ 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 +1728,7 @@ 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) {
@@ -1632,26 +1764,61 @@ out_fmt:
        return error; 
 }
 
-/* Actual function called from quotactl() */
-int vfs_quota_on(struct super_block *sb, int type, int format_id, char *path)
+/* Reenable quotas on remount RW */
+static int vfs_quota_on_remount(struct super_block *sb, int type)
 {
-       struct nameidata nd;
-       int error;
+       struct quota_info *dqopt = sb_dqopt(sb);
+       struct inode *inode;
+       int ret;
 
-       error = path_lookup(path, LOOKUP_FOLLOW, &nd);
-       if (error < 0)
-               return error;
-       error = security_quota_on(nd.path.dentry);
+       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;
+}
+
+int vfs_quota_on_path(struct super_block *sb, int type, int format_id,
+                     struct path *path)
+{
+       int error = security_quota_on(path->dentry);
        if (error)
-               goto out_path;
+               return error;
        /* Quota file not on the same filesystem? */
-       if (nd.path.mnt->mnt_sb != sb)
+       if (path->mnt->mnt_sb != sb)
                error = -EXDEV;
        else
-               error = vfs_quota_on_inode(nd.path.dentry->d_inode, type,
+               error = vfs_quota_on_inode(path->dentry->d_inode, type,
                                           format_id);
-out_path:
-       path_put(&nd.path);
+       return error;
+}
+
+/* Actual function called from quotactl() */
+int vfs_quota_on(struct super_block *sb, int type, int format_id, char *name,
+                int remount)
+{
+       struct path path;
+       int error;
+
+       if (remount)
+               return vfs_quota_on_remount(sb, type);
+
+       error = kern_path(name, LOOKUP_FOLLOW, &path);
+       if (!error) {
+               error = vfs_quota_on_path(sb, type, format_id, &path);
+               path_put(&path);
+       }
        return error;
 }
 
@@ -1683,6 +1850,22 @@ out:
        return error;
 }
 
+/* Wrapper to turn on quotas when remounting rw */
+int vfs_dq_quota_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;
+}
+
 /* Generic routine for getting common part of quota structure */
 static void do_get_dqblk(struct dquot *dquot, struct if_dqblk *di)
 {
@@ -2004,6 +2187,7 @@ EXPORT_SYMBOL(unregister_quota_format);
 EXPORT_SYMBOL(dqstats);
 EXPORT_SYMBOL(dq_data_lock);
 EXPORT_SYMBOL(vfs_quota_on);
+EXPORT_SYMBOL(vfs_quota_on_path);
 EXPORT_SYMBOL(vfs_quota_on_mount);
 EXPORT_SYMBOL(vfs_quota_off);
 EXPORT_SYMBOL(vfs_quota_sync);
@@ -2018,8 +2202,11 @@ EXPORT_SYMBOL(dquot_release);
 EXPORT_SYMBOL(dquot_mark_dquot_dirty);
 EXPORT_SYMBOL(dquot_initialize);
 EXPORT_SYMBOL(dquot_drop);
+EXPORT_SYMBOL(vfs_dq_drop);
 EXPORT_SYMBOL(dquot_alloc_space);
 EXPORT_SYMBOL(dquot_alloc_inode);
 EXPORT_SYMBOL(dquot_free_space);
 EXPORT_SYMBOL(dquot_free_inode);
 EXPORT_SYMBOL(dquot_transfer);
+EXPORT_SYMBOL(vfs_dq_transfer);
+EXPORT_SYMBOL(vfs_dq_quota_on_remount);