[PATCH 00/10] quotactl fixed and cleanups

[PATCH 00/10] quotactl fixed and cleanups

[Christoph Hellwig]

This is a first large batch of refactoring the generic quotactl code.
I started looking at this for merging the FS interfaces for "VFS" and "XFS"
style quotas now that we grow more filesystems wanting to support quota
in a more advanced way than the generic implementation can, e.g. GFS2
and cifs.  There will be another couple of patches do do the actual
work which are not quite ready, but this is a large and useful enough batch
to get review and possibly included first.

[PATCH 01/10] quota: split do_quotactl

[Christoph Hellwig]

[-- Attachment #1: quotactl-cleanup --]
[-- Type: text/plain, Size: 7090 bytes --]

Split out a helper for each non-trivial command from do_quotactl.

Signed-off-by: Christoph Hellwig <hch@lst.de>

Index: linux-2.6/fs/quota/quota.c
===================================================================
--- linux-2.6.orig/fs/quota/quota.c	2010-02-08 19:26:09.316003867 +0100
+++ linux-2.6/fs/quota/quota.c	2010-02-08 19:28:14.176005193 +0100
@@ -234,122 +234,164 @@ restart:
 	spin_unlock(&sb_lock);
 }
 
-/* Copy parameters and call proper function */
-static int do_quotactl(struct super_block *sb, int type, int cmd, qid_t id,
-		       void __user *addr)
+static int quota_quotaon(struct super_block *sb, int type, int cmd, qid_t id,
+		         void __user *addr)
 {
+	char *pathname;
 	int ret;
 
-	switch (cmd) {
-		case Q_QUOTAON: {
-			char *pathname;
+	pathname = getname(addr);
+	if (IS_ERR(pathname))
+		return PTR_ERR(pathname);
+	ret = sb->s_qcop->quota_on(sb, type, id, pathname, 0);
+	putname(pathname);
+	return ret;
+}
+
+static int quota_getfmt(struct super_block *sb, int type, void __user *addr)
+{
+	__u32 fmt;
+
+	down_read(&sb_dqopt(sb)->dqptr_sem);
+	if (!sb_has_quota_active(sb, type)) {
+		up_read(&sb_dqopt(sb)->dqptr_sem);
+		return -ESRCH;
+	}
+	fmt = sb_dqopt(sb)->info[type].dqi_format->qf_fmt_id;
+	up_read(&sb_dqopt(sb)->dqptr_sem);
+	if (copy_to_user(addr, &fmt, sizeof(fmt)))
+		return -EFAULT;
+	return 0;
+}
+
+static int quota_getinfo(struct super_block *sb, int type, void __user *addr)
+{
+	struct if_dqinfo info;
+	int ret;
+
+	ret = sb->s_qcop->get_info(sb, type, &info);
+	if (!ret && copy_to_user(addr, &info, sizeof(info)))
+		return -EFAULT;
+	return ret;
+}
+
+static int quota_setinfo(struct super_block *sb, int type, void __user *addr)
+{
+	struct if_dqinfo info;
+
+	if (copy_from_user(&info, addr, sizeof(info)))
+		return -EFAULT;
+	return sb->s_qcop->set_info(sb, type, &info);
+}
+
+static int quota_getquota(struct super_block *sb, int type, qid_t id,
+			  void __user *addr)
+{
+	struct if_dqblk idq;
+	int ret;
+
+	ret = sb->s_qcop->get_dqblk(sb, type, id, &idq);
+	if (ret)
+		return ret;
+	if (copy_to_user(addr, &idq, sizeof(idq)))
+		return -EFAULT;
+	return 0;
+}
+
+static int quota_setquota(struct super_block *sb, int type, qid_t id,
+			  void __user *addr)
+{
+	struct if_dqblk idq;
 
-			pathname = getname(addr);
-			if (IS_ERR(pathname))
-				return PTR_ERR(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, 0);
-
-		case Q_GETFMT: {
-			__u32 fmt;
-
-			down_read(&sb_dqopt(sb)->dqptr_sem);
-			if (!sb_has_quota_active(sb, type)) {
-				up_read(&sb_dqopt(sb)->dqptr_sem);
-				return -ESRCH;
-			}
-			fmt = sb_dqopt(sb)->info[type].dqi_format->qf_fmt_id;
-			up_read(&sb_dqopt(sb)->dqptr_sem);
-			if (copy_to_user(addr, &fmt, sizeof(fmt)))
-				return -EFAULT;
-			return 0;
-		}
-		case Q_GETINFO: {
-			struct if_dqinfo info;
-
-			ret = sb->s_qcop->get_info(sb, type, &info);
-			if (ret)
-				return ret;
-			if (copy_to_user(addr, &info, sizeof(info)))
-				return -EFAULT;
-			return 0;
-		}
-		case Q_SETINFO: {
-			struct if_dqinfo info;
-
-			if (copy_from_user(&info, addr, sizeof(info)))
-				return -EFAULT;
-			return sb->s_qcop->set_info(sb, type, &info);
-		}
-		case Q_GETQUOTA: {
-			struct if_dqblk idq;
-
-			ret = sb->s_qcop->get_dqblk(sb, type, id, &idq);
-			if (ret)
-				return ret;
-			if (copy_to_user(addr, &idq, sizeof(idq)))
-				return -EFAULT;
-			return 0;
-		}
-		case Q_SETQUOTA: {
-			struct if_dqblk idq;
-
-			if (copy_from_user(&idq, addr, sizeof(idq)))
-				return -EFAULT;
-			return sb->s_qcop->set_dqblk(sb, type, id, &idq);
-		}
-		case Q_SYNC:
-			if (sb)
-				sync_quota_sb(sb, type);
-			else
-				sync_dquots(type);
-			return 0;
-
-		case Q_XQUOTAON:
-		case Q_XQUOTAOFF:
-		case Q_XQUOTARM: {
-			__u32 flags;
-
-			if (copy_from_user(&flags, addr, sizeof(flags)))
-				return -EFAULT;
-			return sb->s_qcop->set_xstate(sb, flags, cmd);
-		}
-		case Q_XGETQSTAT: {
-			struct fs_quota_stat fqs;
+	if (copy_from_user(&idq, addr, sizeof(idq)))
+		return -EFAULT;
+	return sb->s_qcop->set_dqblk(sb, type, id, &idq);
+}
+
+static int quota_setxstate(struct super_block *sb, int cmd, void __user *addr)
+{
+	__u32 flags;
+
+	if (copy_from_user(&flags, addr, sizeof(flags)))
+		return -EFAULT;
+	return sb->s_qcop->set_xstate(sb, flags, cmd);
+}
+
+static int quota_getxstate(struct super_block *sb, void __user *addr)
+{
+	struct fs_quota_stat fqs;
+	int ret;
 		
-			if ((ret = sb->s_qcop->get_xstate(sb, &fqs)))
-				return ret;
-			if (copy_to_user(addr, &fqs, sizeof(fqs)))
-				return -EFAULT;
-			return 0;
-		}
-		case Q_XSETQLIM: {
-			struct fs_disk_quota fdq;
-
-			if (copy_from_user(&fdq, addr, sizeof(fdq)))
-				return -EFAULT;
-		       return sb->s_qcop->set_xquota(sb, type, id, &fdq);
-		}
-		case Q_XGETQUOTA: {
-			struct fs_disk_quota fdq;
-
-			ret = sb->s_qcop->get_xquota(sb, type, id, &fdq);
-			if (ret)
-				return ret;
-			if (copy_to_user(addr, &fdq, sizeof(fdq)))
-				return -EFAULT;
-			return 0;
-		}
-		case Q_XQUOTASYNC:
-			return sb->s_qcop->quota_sync(sb, type);
-		/* We never reach here unless validity check is broken */
-		default:
-			BUG();
+	ret = sb->s_qcop->get_xstate(sb, &fqs);
+	if (!ret && copy_to_user(addr, &fqs, sizeof(fqs)))
+		return -EFAULT;
+	return ret;
+}
+
+static int quota_setxquota(struct super_block *sb, int type, qid_t id,
+			   void __user *addr)
+{
+	struct fs_disk_quota fdq;
+
+	if (copy_from_user(&fdq, addr, sizeof(fdq)))
+		return -EFAULT;
+	return sb->s_qcop->set_xquota(sb, type, id, &fdq);
+}
+
+static int quota_getxquota(struct super_block *sb, int type, qid_t id,
+			   void __user *addr)
+{
+	struct fs_disk_quota fdq;
+	int ret;
+
+	ret = sb->s_qcop->get_xquota(sb, type, id, &fdq);
+	if (!ret && copy_to_user(addr, &fdq, sizeof(fdq)))
+		return -EFAULT;
+	return ret;
+}
+
+/* Copy parameters and call proper function */
+static int do_quotactl(struct super_block *sb, int type, int cmd, qid_t id,
+		       void __user *addr)
+{
+	switch (cmd) {
+	case Q_QUOTAON:
+		return quota_quotaon(sb, type, cmd, id, addr);
+	case Q_QUOTAOFF:
+		return sb->s_qcop->quota_off(sb, type, 0);
+	case Q_GETFMT:
+		return quota_getfmt(sb, type, addr);
+	case Q_GETINFO:
+		return quota_getinfo(sb, type, addr);
+	case Q_SETINFO:
+		return quota_setinfo(sb, type, addr);
+	case Q_GETQUOTA:
+		return quota_getquota(sb, type, id, addr);
+	case Q_SETQUOTA:
+		return quota_setquota(sb, type, id, addr);
+	case Q_SYNC:
+		if (sb)
+			sync_quota_sb(sb, type);
+		else
+			sync_dquots(type);
+		return 0;
+	case Q_XQUOTAON:
+	case Q_XQUOTAOFF:
+	case Q_XQUOTARM:
+		return quota_setxstate(sb, cmd, addr);
+	case Q_XGETQSTAT:
+		return quota_getxstate(sb, addr);
+	case Q_XSETQLIM:
+		return quota_setxquota(sb, type, id, addr);
+	case Q_XGETQUOTA:
+		return quota_getxquota(sb, type, id, addr);
+	case Q_XQUOTASYNC:
+		return sb->s_qcop->quota_sync(sb, type);
+	/* We never reach here unless validity check is broken */
+	default:
+		BUG();
 	}
+
 	return 0;
 }
 

[PATCH 02/10] quota: clean up checks for supported quota methods

[Christoph Hellwig]

[-- Attachment #1: quotactl-cleanup-2 --]
[-- Type: text/plain, Size: 5972 bytes --]

Move the checks for sb->s_qcop->foo next to the actual calls for them, same
for sb_has_quota_active checks where applicable.

Signed-off-by: Christoph Hellwig <hch@lst.de>

Index: linux-2.6/fs/quota/quota.c
===================================================================
--- linux-2.6.orig/fs/quota/quota.c	2010-02-09 17:10:31.563263527 +0100
+++ linux-2.6/fs/quota/quota.c	2010-02-09 17:11:23.314004970 +0100
@@ -33,54 +33,6 @@ static int generic_quotactl_valid(struct
 	if (sb && !sb->s_qcop)
 		return -ENOSYS;
 
-	switch (cmd) {
-		case Q_GETFMT:
-			break;
-		case Q_QUOTAON:
-			if (!sb->s_qcop->quota_on)
-				return -ENOSYS;
-			break;
-		case Q_QUOTAOFF:
-			if (!sb->s_qcop->quota_off)
-				return -ENOSYS;
-			break;
-		case Q_SETINFO:
-			if (!sb->s_qcop->set_info)
-				return -ENOSYS;
-			break;
-		case Q_GETINFO:
-			if (!sb->s_qcop->get_info)
-				return -ENOSYS;
-			break;
-		case Q_SETQUOTA:
-			if (!sb->s_qcop->set_dqblk)
-				return -ENOSYS;
-			break;
-		case Q_GETQUOTA:
-			if (!sb->s_qcop->get_dqblk)
-				return -ENOSYS;
-			break;
-		case Q_SYNC:
-			if (sb && !sb->s_qcop->quota_sync)
-				return -ENOSYS;
-			break;
-		default:
-			return -EINVAL;
-	}
-
-	/* Is quota turned on for commands which need it? */
-	switch (cmd) {
-		case Q_GETFMT:
-		case Q_GETINFO:
-		case Q_SETINFO:
-		case Q_SETQUOTA:
-		case Q_GETQUOTA:
-			/* This is just an informative test so we are satisfied
-			 * without the lock */
-			if (!sb_has_quota_active(sb, type))
-				return -ESRCH;
-	}
-
 	/* Check privileges */
 	if (cmd == Q_GETQUOTA) {
 		if (((type == USRQUOTA && current_euid() != id) ||
@@ -106,33 +58,6 @@ static int xqm_quotactl_valid(struct sup
 	if (!sb->s_qcop)
 		return -ENOSYS;
 
-	switch (cmd) {
-		case Q_XQUOTAON:
-		case Q_XQUOTAOFF:
-		case Q_XQUOTARM:
-			if (!sb->s_qcop->set_xstate)
-				return -ENOSYS;
-			break;
-		case Q_XGETQSTAT:
-			if (!sb->s_qcop->get_xstate)
-				return -ENOSYS;
-			break;
-		case Q_XSETQLIM:
-			if (!sb->s_qcop->set_xquota)
-				return -ENOSYS;
-			break;
-		case Q_XGETQUOTA:
-			if (!sb->s_qcop->get_xquota)
-				return -ENOSYS;
-			break;
-		case Q_XQUOTASYNC:
-			if (!sb->s_qcop->quota_sync)
-				return -ENOSYS;
-			break;
-		default:
-			return -EINVAL;
-	}
-
 	/* Check privileges */
 	if (cmd == Q_XGETQUOTA) {
 		if (((type == XQM_USRQUOTA && current_euid() != id) ||
@@ -238,12 +163,13 @@ static int quota_quotaon(struct super_bl
 		         void __user *addr)
 {
 	char *pathname;
-	int ret;
+	int ret = -ENOSYS;
 
 	pathname = getname(addr);
 	if (IS_ERR(pathname))
 		return PTR_ERR(pathname);
-	ret = sb->s_qcop->quota_on(sb, type, id, pathname, 0);
+	if (sb->s_qcop->quota_on)
+		ret = sb->s_qcop->quota_on(sb, type, id, pathname, 0);
 	putname(pathname);
 	return ret;
 }
@@ -269,6 +195,10 @@ static int quota_getinfo(struct super_bl
 	struct if_dqinfo info;
 	int ret;
 
+	if (!sb_has_quota_active(sb, type))
+		return -ESRCH;
+	if (!sb->s_qcop->get_info)
+		return -ENOSYS;
 	ret = sb->s_qcop->get_info(sb, type, &info);
 	if (!ret && copy_to_user(addr, &info, sizeof(info)))
 		return -EFAULT;
@@ -281,6 +211,10 @@ static int quota_setinfo(struct super_bl
 
 	if (copy_from_user(&info, addr, sizeof(info)))
 		return -EFAULT;
+	if (!sb_has_quota_active(sb, type))
+		return -ESRCH;
+	if (!sb->s_qcop->set_info)
+		return -ENOSYS;
 	return sb->s_qcop->set_info(sb, type, &info);
 }
 
@@ -290,6 +224,10 @@ static int quota_getquota(struct super_b
 	struct if_dqblk idq;
 	int ret;
 
+	if (!sb_has_quota_active(sb, type))
+		return -ESRCH;
+	if (!sb->s_qcop->get_dqblk)
+		return -ENOSYS;
 	ret = sb->s_qcop->get_dqblk(sb, type, id, &idq);
 	if (ret)
 		return ret;
@@ -305,6 +243,10 @@ static int quota_setquota(struct super_b
 
 	if (copy_from_user(&idq, addr, sizeof(idq)))
 		return -EFAULT;
+	if (!sb_has_quota_active(sb, type))
+		return -ESRCH;
+	if (!sb->s_qcop->set_dqblk)
+		return -ENOSYS;
 	return sb->s_qcop->set_dqblk(sb, type, id, &idq);
 }
 
@@ -314,6 +256,8 @@ static int quota_setxstate(struct super_
 
 	if (copy_from_user(&flags, addr, sizeof(flags)))
 		return -EFAULT;
+	if (!sb->s_qcop->set_xstate)
+		return -ENOSYS;
 	return sb->s_qcop->set_xstate(sb, flags, cmd);
 }
 
@@ -321,7 +265,9 @@ static int quota_getxstate(struct super_
 {
 	struct fs_quota_stat fqs;
 	int ret;
-		
+
+	if (!sb->s_qcop->get_xstate)
+		return -ENOSYS;
 	ret = sb->s_qcop->get_xstate(sb, &fqs);
 	if (!ret && copy_to_user(addr, &fqs, sizeof(fqs)))
 		return -EFAULT;
@@ -335,6 +281,8 @@ static int quota_setxquota(struct super_
 
 	if (copy_from_user(&fdq, addr, sizeof(fdq)))
 		return -EFAULT;
+	if (!sb->s_qcop->set_xquota)
+		return -ENOSYS;
 	return sb->s_qcop->set_xquota(sb, type, id, &fdq);
 }
 
@@ -344,6 +292,8 @@ static int quota_getxquota(struct super_
 	struct fs_disk_quota fdq;
 	int ret;
 
+	if (!sb->s_qcop->get_xquota)
+		return -ENOSYS;
 	ret = sb->s_qcop->get_xquota(sb, type, id, &fdq);
 	if (!ret && copy_to_user(addr, &fdq, sizeof(fdq)))
 		return -EFAULT;
@@ -358,6 +308,8 @@ static int do_quotactl(struct super_bloc
 	case Q_QUOTAON:
 		return quota_quotaon(sb, type, cmd, id, addr);
 	case Q_QUOTAOFF:
+		if (!sb->s_qcop->quota_off)
+			return -ENOSYS;
 		return sb->s_qcop->quota_off(sb, type, 0);
 	case Q_GETFMT:
 		return quota_getfmt(sb, type, addr);
@@ -370,9 +322,11 @@ static int do_quotactl(struct super_bloc
 	case Q_SETQUOTA:
 		return quota_setquota(sb, type, id, addr);
 	case Q_SYNC:
-		if (sb)
+		if (sb) {
+			if (!sb->s_qcop->quota_sync)
+				return -ENOSYS;
 			sync_quota_sb(sb, type);
-		else
+		} else
 			sync_dquots(type);
 		return 0;
 	case Q_XQUOTAON:
@@ -386,13 +340,12 @@ static int do_quotactl(struct super_bloc
 	case Q_XGETQUOTA:
 		return quota_getxquota(sb, type, id, addr);
 	case Q_XQUOTASYNC:
+		if (!sb->s_qcop->quota_sync)
+			return -ENOSYS;
 		return sb->s_qcop->quota_sync(sb, type);
-	/* We never reach here unless validity check is broken */
 	default:
-		BUG();
+		return -EINVAL;
 	}
-
-	return 0;
 }
 
 /*

[PATCH 03/10] quota: special case Q_SYNC without device name

[Christoph Hellwig]

[-- Attachment #1: quotactl-cleanup-3 --]
[-- Type: text/plain, Size: 2253 bytes --]

The Q_SYNC command can be called without the path to a device, in which case
it iterates over all superblocks.  Special case this variant directly in
sys_quotactl so that the other code always gets a superblock and doesn't
need to deal with this case.

Signed-off-by: Christoph Hellwig <hch@lst.de>

Index: linux-2.6/fs/quota/quota.c
===================================================================
--- linux-2.6.orig/fs/quota/quota.c	2010-02-10 13:19:42.247004063 +0100
+++ linux-2.6/fs/quota/quota.c	2010-02-10 13:21:01.300003435 +0100
@@ -124,10 +124,17 @@ void sync_quota_sb(struct super_block *s
 }
 #endif
 
-static void sync_dquots(int type)
+static int quota_sync_all(int type)
 {
 	struct super_block *sb;
 	int cnt;
+	int ret;
+
+	if (type >= MAXQUOTAS)
+		return -EINVAL;
+	ret = security_quotactl(Q_SYNC, type, 0, NULL);
+	if (ret)
+		return ret;
 
 	spin_lock(&sb_lock);
 restart:
@@ -157,6 +164,8 @@ restart:
 			goto restart;
 	}
 	spin_unlock(&sb_lock);
+
+	return 0;
 }
 
 static int quota_quotaon(struct super_block *sb, int type, int cmd, qid_t id,
@@ -322,12 +331,9 @@ static int do_quotactl(struct super_bloc
 	case Q_SETQUOTA:
 		return quota_setquota(sb, type, id, addr);
 	case Q_SYNC:
-		if (sb) {
-			if (!sb->s_qcop->quota_sync)
-				return -ENOSYS;
-			sync_quota_sb(sb, type);
-		} else
-			sync_dquots(type);
+		if (!sb->s_qcop->quota_sync)
+			return -ENOSYS;
+		sync_quota_sb(sb, type);
 		return 0;
 	case Q_XQUOTAON:
 	case Q_XQUOTAOFF:
@@ -392,18 +398,26 @@ SYSCALL_DEFINE4(quotactl, unsigned int, 
 	cmds = cmd >> SUBCMDSHIFT;
 	type = cmd & SUBCMDMASK;
 
-	if (cmds != Q_SYNC || special) {
-		sb = quotactl_block(special);
-		if (IS_ERR(sb))
-			return PTR_ERR(sb);
+	/*
+	 * As a special case Q_SYNC can be called without a specific device.
+	 * It will iterate all superblocks that have quota enabled and call
+	 * the sync action on each of them.
+	 */
+	if (!special) {
+		if (cmds == Q_SYNC)
+			return quota_sync_all(type);
+		return -ENODEV;
 	}
 
+	sb = quotactl_block(special);
+	if (IS_ERR(sb))
+		return PTR_ERR(sb);
+
 	ret = check_quotactl_valid(sb, type, cmds, id);
 	if (ret >= 0)
 		ret = do_quotactl(sb, type, cmds, id, addr);
-	if (sb)
-		drop_super(sb);
 
+	drop_super(sb);
 	return ret;
 }
 

[PATCH 04/10] quota: simplify permission checking

[Christoph Hellwig]

[-- Attachment #1: quotactl-cleanup-4 --]
[-- Type: text/plain, Size: 3669 bytes --]

Stop having complicated different routines for checking permissions for
XQM vs "VFS" quotas.  Instead do the checks for having sb->s_qcop and
a valid type diretly in do_quotactl, and munge the *quotactl_valid functions
into a check_quotactl_permission helper that only checks for permissions.

Signed-off-by: Christoph Hellwig <hch@lst.de>

Index: linux-2.6/fs/quota/quota.c
===================================================================
--- linux-2.6.orig/fs/quota/quota.c	2010-02-11 15:54:40.313002736 +0100
+++ linux-2.6/fs/quota/quota.c	2010-02-11 16:11:22.005254866 +0100
@@ -21,69 +21,30 @@
 #include <net/netlink.h>
 #include <net/genetlink.h>
 
-/* Check validity of generic quotactl commands */
-static int generic_quotactl_valid(struct super_block *sb, int type, int cmd,
-				  qid_t id)
+static int check_quotactl_permission(struct super_block *sb, int type, int cmd,
+				     qid_t id)
 {
-	if (type >= MAXQUOTAS)
-		return -EINVAL;
-	if (!sb && cmd != Q_SYNC)
-		return -ENODEV;
-	/* Is operation supported? */
-	if (sb && !sb->s_qcop)
-		return -ENOSYS;
-
-	/* Check privileges */
-	if (cmd == Q_GETQUOTA) {
-		if (((type == USRQUOTA && current_euid() != id) ||
-		     (type == GRPQUOTA && !in_egroup_p(id))) &&
-		    !capable(CAP_SYS_ADMIN))
-			return -EPERM;
-	}
-	else if (cmd != Q_GETFMT && cmd != Q_SYNC && cmd != Q_GETINFO)
-		if (!capable(CAP_SYS_ADMIN))
-			return -EPERM;
-
-	return 0;
-}
-
-/* Check validity of XFS Quota Manager commands */
-static int xqm_quotactl_valid(struct super_block *sb, int type, int cmd,
-			      qid_t id)
-{
-	if (type >= XQM_MAXQUOTAS)
-		return -EINVAL;
-	if (!sb)
-		return -ENODEV;
-	if (!sb->s_qcop)
-		return -ENOSYS;
-
-	/* Check privileges */
-	if (cmd == Q_XGETQUOTA) {
-		if (((type == XQM_USRQUOTA && current_euid() != id) ||
-		     (type == XQM_GRPQUOTA && !in_egroup_p(id))) &&
-		     !capable(CAP_SYS_ADMIN))
-			return -EPERM;
-	} else if (cmd != Q_XGETQSTAT && cmd != Q_XQUOTASYNC) {
-		if (!capable(CAP_SYS_ADMIN))
+	switch (cmd) {
+	/* these commands do not require any special privilegues */
+ 	case Q_GETFMT:
+ 	case Q_SYNC:
+ 	case Q_GETINFO:
+ 	case Q_XGETQSTAT:
+ 	case Q_XQUOTASYNC:
+ 		break;
+	/* allow to query information for dquots we "own" */
+	case Q_GETQUOTA:
+	case Q_XGETQUOTA:
+		if ((type == USRQUOTA && current_euid() == id) ||
+		    (type == GRPQUOTA && in_egroup_p(id)))
+			break;
+		/*FALLTHROUGH*/
+ 	default:
+ 		if (!capable(CAP_SYS_ADMIN))
 			return -EPERM;
 	}
 
-	return 0;
-}
-
-static int check_quotactl_valid(struct super_block *sb, int type, int cmd,
-				qid_t id)
-{
-	int error;
-
-	if (XQM_COMMAND(cmd))
-		error = xqm_quotactl_valid(sb, type, cmd, id);
-	else
-		error = generic_quotactl_valid(sb, type, cmd, id);
-	if (!error)
-		error = security_quotactl(cmd, type, id, sb);
-	return error;
+	return security_quotactl(cmd, type, id, sb);
 }
 
 #ifdef CONFIG_QUOTA
@@ -313,6 +274,17 @@ static int quota_getxquota(struct super_
 static int do_quotactl(struct super_block *sb, int type, int cmd, qid_t id,
 		       void __user *addr)
 {
+	int ret;
+
+	if (type >= (XQM_COMMAND(cmd) ? XQM_MAXQUOTAS : MAXQUOTAS))
+ 		return -EINVAL;
+	if (!sb->s_qcop)
+ 		return -ENOSYS;
+
+	ret = check_quotactl_permission(sb, type, cmd, id);
+	if (ret < 0)
+		return ret;
+
 	switch (cmd) {
 	case Q_QUOTAON:
 		return quota_quotaon(sb, type, cmd, id, addr);
@@ -413,9 +385,7 @@ SYSCALL_DEFINE4(quotactl, unsigned int, 
 	if (IS_ERR(sb))
 		return PTR_ERR(sb);
 
-	ret = check_quotactl_valid(sb, type, cmds, id);
-	if (ret >= 0)
-		ret = do_quotactl(sb, type, cmds, id, addr);
+	ret = do_quotactl(sb, type, cmds, id, addr);
 
 	drop_super(sb);
 	return ret;

[PATCH 05/10] quota: clean up Q_XQUOTASYNC

[Christoph Hellwig]

[-- Attachment #1: cleanup-Q_XQUOTASYNC --]
[-- Type: text/plain, Size: 3310 bytes --]

Currently Q_XQUOTASYNC calls into the quota_sync method, but XFS does something
entirely different in it than the rest of the filesystems.  xfs_quota which
calls Q_XQUOTASYNC expects an asynchronous data writeout to flush delayed
allocations, while the "VFS" quota support wants to flush changes to the quota
file.

So make Q_XQUOTASYNC call into the writeback code directly and make the
quota_sync method optional as XFS doesn't need in the sense expected by the
rest of the quota code.

GFS2 was using limited XFS-style quota and has a quota_sync method fitting
neither the style used by vfs_quota_sync nor xfs_fs_quota_sync.  I left it
in for now as per discussion with Steve it expects to be called from the
sync path this way.

Signed-off-by: Christoph Hellwig <hch@lst.de>

Index: linux-2.6/fs/quota/quota.c
===================================================================
--- linux-2.6.orig/fs/quota/quota.c	2010-02-16 00:15:27.136003612 +0100
+++ linux-2.6/fs/quota/quota.c	2010-02-16 00:16:03.263004031 +0100
@@ -18,6 +18,7 @@
 #include <linux/capability.h>
 #include <linux/quotaops.h>
 #include <linux/types.h>
+#include <linux/writeback.h>
 #include <net/netlink.h>
 #include <net/genetlink.h>
 
@@ -52,7 +53,7 @@ void sync_quota_sb(struct super_block *s
 {
 	int cnt;
 
-	if (!sb->s_qcop->quota_sync)
+	if (!sb->s_qcop || !sb->s_qcop->quota_sync)
 		return;
 
 	sb->s_qcop->quota_sync(sb, type);
@@ -318,9 +319,11 @@ static int do_quotactl(struct super_bloc
 	case Q_XGETQUOTA:
 		return quota_getxquota(sb, type, id, addr);
 	case Q_XQUOTASYNC:
-		if (!sb->s_qcop->quota_sync)
-			return -ENOSYS;
-		return sb->s_qcop->quota_sync(sb, type);
+		/* caller already holds s_umount */
+		if (sb->s_flags & MS_RDONLY)
+			return -EROFS;
+		writeback_inodes_sb(sb);
+		return 0;
 	default:
 		return -EINVAL;
 	}
Index: linux-2.6/fs/xfs/linux-2.6/xfs_quotaops.c
===================================================================
--- linux-2.6.orig/fs/xfs/linux-2.6/xfs_quotaops.c	2010-02-16 00:13:44.399004869 +0100
+++ linux-2.6/fs/xfs/linux-2.6/xfs_quotaops.c	2010-02-16 00:15:27.709004380 +0100
@@ -44,20 +44,6 @@ xfs_quota_type(int type)
 }
 
 STATIC int
-xfs_fs_quota_sync(
-	struct super_block	*sb,
-	int			type)
-{
-	struct xfs_mount	*mp = XFS_M(sb);
-
-	if (sb->s_flags & MS_RDONLY)
-		return -EROFS;
-	if (!XFS_IS_QUOTA_RUNNING(mp))
-		return -ENOSYS;
-	return -xfs_sync_data(mp, 0);
-}
-
-STATIC int
 xfs_fs_get_xstate(
 	struct super_block	*sb,
 	struct fs_quota_stat	*fqs)
@@ -151,7 +137,6 @@ xfs_fs_set_xquota(
 }
 
 const struct quotactl_ops xfs_quotactl_operations = {
-	.quota_sync		= xfs_fs_quota_sync,
 	.get_xstate		= xfs_fs_get_xstate,
 	.set_xstate		= xfs_fs_set_xstate,
 	.get_xquota		= xfs_fs_get_xquota,
Index: linux-2.6/include/linux/quotaops.h
===================================================================
--- linux-2.6.orig/include/linux/quotaops.h	2010-02-16 00:16:06.788003612 +0100
+++ linux-2.6/include/linux/quotaops.h	2010-02-16 00:16:15.361004730 +0100
@@ -22,7 +22,7 @@ static inline struct quota_info *sb_dqop
 void sync_quota_sb(struct super_block *sb, int type);
 static inline void writeout_quota_sb(struct super_block *sb, int type)
 {
-	if (sb->s_qcop->quota_sync)
+	if (sb->s_qcop && sb->s_qcop->quota_sync)
 		sb->s_qcop->quota_sync(sb, type);
 }
 

[PATCH 06/10] quota: move code from sync_quota_sb into vfs_quota_sync

[Christoph Hellwig]

[-- Attachment #1: quota-cleanup-sync --]
[-- Type: text/plain, Size: 7555 bytes --]

Currenly sync_quota_sb does a lot of sync and truncate action that only
applies to "VFS" style quotas and is actively harmful for the sync
performance in XFS.  Move it into vfs_quota_sync and add a wait paramter
to ->quota_sync to tell if we need it or not.

My audit of the GFS2 code says it's also not needed given the way GFS2
implements quotas, but I'd be happy if this can get a detailed review.

Signed-off-by: Christoph Hellwig <hch@lst.de>

Index: linux-2.6/fs/quota/dquot.c
===================================================================
--- linux-2.6.orig/fs/quota/dquot.c	2010-02-16 00:13:43.000000000 +0100
+++ linux-2.6/fs/quota/dquot.c	2010-02-16 00:19:51.642255742 +0100
@@ -564,7 +564,7 @@ out:
 }
 EXPORT_SYMBOL(dquot_scan_active);
 
-int vfs_quota_sync(struct super_block *sb, int type)
+int vfs_quota_sync(struct super_block *sb, int type, int wait)
 {
 	struct list_head *dirty;
 	struct dquot *dquot;
@@ -609,6 +609,33 @@ int vfs_quota_sync(struct super_block *s
 	spin_unlock(&dq_list_lock);
 	mutex_unlock(&dqopt->dqonoff_mutex);
 
+	if (!wait || (sb_dqopt(sb)->flags & DQUOT_QUOTA_SYS_FILE))
+		return 0;
+
+	/* This is not very clever (and fast) but currently I don't know about
+	 * any other simple way of getting quota data to disk and we must get
+	 * them there for userspace to be visible... */
+	if (sb->s_op->sync_fs)
+		sb->s_op->sync_fs(sb, 1);
+	sync_blockdev(sb->s_bdev);
+
+	/*
+	 * Now when everything is written we can discard the pagecache so
+	 * that userspace sees the changes.
+	 */
+	mutex_lock(&sb_dqopt(sb)->dqonoff_mutex);
+	for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
+		if (type != -1 && cnt != type)
+			continue;
+		if (!sb_has_quota_active(sb, cnt))
+			continue;
+		mutex_lock_nested(&sb_dqopt(sb)->files[cnt]->i_mutex,
+				  I_MUTEX_QUOTA);
+		truncate_inode_pages(&sb_dqopt(sb)->files[cnt]->i_data, 0);
+		mutex_unlock(&sb_dqopt(sb)->files[cnt]->i_mutex);
+	}
+	mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
+
 	return 0;
 }
 EXPORT_SYMBOL(vfs_quota_sync);
Index: linux-2.6/fs/quota/quota.c
===================================================================
--- linux-2.6.orig/fs/quota/quota.c	2010-02-16 00:16:29.030004171 +0100
+++ linux-2.6/fs/quota/quota.c	2010-02-16 00:23:57.795005847 +0100
@@ -48,44 +48,6 @@ static int check_quotactl_permission(str
 	return security_quotactl(cmd, type, id, sb);
 }
 
-#ifdef CONFIG_QUOTA
-void sync_quota_sb(struct super_block *sb, int type)
-{
-	int cnt;
-
-	if (!sb->s_qcop || !sb->s_qcop->quota_sync)
-		return;
-
-	sb->s_qcop->quota_sync(sb, type);
-
-	if (sb_dqopt(sb)->flags & DQUOT_QUOTA_SYS_FILE)
-		return;
-	/* This is not very clever (and fast) but currently I don't know about
-	 * any other simple way of getting quota data to disk and we must get
-	 * them there for userspace to be visible... */
-	if (sb->s_op->sync_fs)
-		sb->s_op->sync_fs(sb, 1);
-	sync_blockdev(sb->s_bdev);
-
-	/*
-	 * Now when everything is written we can discard the pagecache so
-	 * that userspace sees the changes.
-	 */
-	mutex_lock(&sb_dqopt(sb)->dqonoff_mutex);
-	for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
-		if (type != -1 && cnt != type)
-			continue;
-		if (!sb_has_quota_active(sb, cnt))
-			continue;
-		mutex_lock_nested(&sb_dqopt(sb)->files[cnt]->i_mutex,
-				  I_MUTEX_QUOTA);
-		truncate_inode_pages(&sb_dqopt(sb)->files[cnt]->i_data, 0);
-		mutex_unlock(&sb_dqopt(sb)->files[cnt]->i_mutex);
-	}
-	mutex_unlock(&sb_dqopt(sb)->dqonoff_mutex);
-}
-#endif
-
 static int quota_sync_all(int type)
 {
 	struct super_block *sb;
@@ -101,6 +63,9 @@ static int quota_sync_all(int type)
 	spin_lock(&sb_lock);
 restart:
 	list_for_each_entry(sb, &super_blocks, s_list) {
+		if (!sb->s_qcop || !sb->s_qcop->quota_sync)
+			continue;
+
 		/* This test just improves performance so it needn't be
 		 * reliable... */
 		for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
@@ -119,7 +84,7 @@ restart:
 		spin_unlock(&sb_lock);
 		down_read(&sb->s_umount);
 		if (sb->s_root)
-			sync_quota_sb(sb, type);
+			sb->s_qcop->quota_sync(sb, type, 1);
 		up_read(&sb->s_umount);
 		spin_lock(&sb_lock);
 		if (__put_super_and_need_restart(sb))
@@ -306,8 +271,7 @@ static int do_quotactl(struct super_bloc
 	case Q_SYNC:
 		if (!sb->s_qcop->quota_sync)
 			return -ENOSYS;
-		sync_quota_sb(sb, type);
-		return 0;
+		return sb->s_qcop->quota_sync(sb, type, 1);
 	case Q_XQUOTAON:
 	case Q_XQUOTAOFF:
 	case Q_XQUOTARM:
Index: linux-2.6/fs/sync.c
===================================================================
--- linux-2.6.orig/fs/sync.c	2010-02-16 00:13:43.000000000 +0100
+++ linux-2.6/fs/sync.c	2010-02-16 00:21:32.283004241 +0100
@@ -34,14 +34,14 @@ static int __sync_filesystem(struct supe
 	if (!sb->s_bdi)
 		return 0;
 
-	/* Avoid doing twice syncing and cache pruning for quota sync */
-	if (!wait) {
-		writeout_quota_sb(sb, -1);
-		writeback_inodes_sb(sb);
-	} else {
-		sync_quota_sb(sb, -1);
+	if (sb->s_qcop && sb->s_qcop->quota_sync)
+		sb->s_qcop->quota_sync(sb, -1, wait);
+
+	if (wait)
 		sync_inodes_sb(sb);
-	}
+	else
+		writeback_inodes_sb(sb);
+
 	if (sb->s_op->sync_fs)
 		sb->s_op->sync_fs(sb, wait);
 	return __sync_blockdev(sb->s_bdev, wait);
Index: linux-2.6/include/linux/quotaops.h
===================================================================
--- linux-2.6.orig/include/linux/quotaops.h	2010-02-16 00:16:15.361004730 +0100
+++ linux-2.6/include/linux/quotaops.h	2010-02-16 00:19:15.186253926 +0100
@@ -19,13 +19,6 @@ static inline struct quota_info *sb_dqop
 /*
  * declaration of quota_function calls in kernel.
  */
-void sync_quota_sb(struct super_block *sb, int type);
-static inline void writeout_quota_sb(struct super_block *sb, int type)
-{
-	if (sb->s_qcop && sb->s_qcop->quota_sync)
-		sb->s_qcop->quota_sync(sb, type);
-}
-
 int dquot_initialize(struct inode *inode, int type);
 int dquot_drop(struct inode *inode);
 struct dquot *dqget(struct super_block *sb, unsigned int id, int type);
@@ -64,7 +57,7 @@ int vfs_quota_on_mount(struct super_bloc
  	int format_id, int type);
 int vfs_quota_off(struct super_block *sb, int type, int remount);
 int vfs_quota_disable(struct super_block *sb, int type, unsigned int flags);
-int vfs_quota_sync(struct super_block *sb, int type);
+int vfs_quota_sync(struct super_block *sb, int type, int wait);
 int vfs_get_dqinfo(struct super_block *sb, int type, struct if_dqinfo *ii);
 int vfs_set_dqinfo(struct super_block *sb, int type, struct if_dqinfo *ii);
 int vfs_get_dqblk(struct super_block *sb, int type, qid_t id, struct if_dqblk *di);
@@ -333,14 +326,6 @@ static inline void vfs_dq_free_inode(str
 {
 }
 
-static inline void sync_quota_sb(struct super_block *sb, int type)
-{
-}
-
-static inline void writeout_quota_sb(struct super_block *sb, int type)
-{
-}
-
 static inline int vfs_dq_off(struct super_block *sb, int remount)
 {
 	return 0;
Index: linux-2.6/include/linux/quota.h
===================================================================
--- linux-2.6.orig/include/linux/quota.h	2010-02-16 00:19:54.595004101 +0100
+++ linux-2.6/include/linux/quota.h	2010-02-16 00:20:00.855004381 +0100
@@ -324,7 +324,7 @@ struct dquot_operations {
 struct quotactl_ops {
 	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 (*quota_sync)(struct super_block *, int, int);
 	int (*get_info)(struct super_block *, int, struct if_dqinfo *);
 	int (*set_info)(struct super_block *, int, struct if_dqinfo *);
 	int (*get_dqblk)(struct super_block *, int, qid_t, struct if_dqblk *);

[PATCH 07/10] quota: remove invalid optimization from quota_sync_all

[Christoph Hellwig]

[-- Attachment #1: make-quota_sync_all-generic --]
[-- Type: text/plain, Size: 1311 bytes --]

Checking the "VFS" quota enabled and dirty bits from generic code means
this code will never get called for other implementations, e.g. XFS and
GFS2.  Grabbing the reference on the superblock really isn't much overhead
for a global Q_SYNC call, so just drop this optimization.

Signed-off-by: Christoph Hellwig <hch@lst.de>

Index: linux-2.6/fs/quota/quota.c
===================================================================
--- linux-2.6.orig/fs/quota/quota.c	2010-02-16 00:24:14.432004170 +0100
+++ linux-2.6/fs/quota/quota.c	2010-02-16 00:24:58.589255532 +0100
@@ -51,7 +51,6 @@ static int check_quotactl_permission(str
 static int quota_sync_all(int type)
 {
 	struct super_block *sb;
-	int cnt;
 	int ret;
 
 	if (type >= MAXQUOTAS)
@@ -66,20 +65,6 @@ restart:
 		if (!sb->s_qcop || !sb->s_qcop->quota_sync)
 			continue;
 
-		/* This test just improves performance so it needn't be
-		 * reliable... */
-		for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
-			if (type != -1 && type != cnt)
-				continue;
-			if (!sb_has_quota_active(sb, cnt))
-				continue;
-			if (!info_dirty(&sb_dqopt(sb)->info[cnt]) &&
-			   list_empty(&sb_dqopt(sb)->info[cnt].dqi_dirty_list))
-				continue;
-			break;
-		}
-		if (cnt == MAXQUOTAS)
-			continue;
 		sb->s_count++;
 		spin_unlock(&sb_lock);
 		down_read(&sb->s_umount);

[PATCH 08/10] quota: split out netlink notification support from quota.c

[Christoph Hellwig]

[-- Attachment #1: split-netlink --]
[-- Type: text/plain, Size: 6674 bytes --]

Instead of adding ifdefs just split it into a new file.

Signed-off-by: Christoph Hellwig <hch@lst.de>

Index: linux-2.6/fs/quota/Makefile
===================================================================
--- linux-2.6.orig/fs/quota/Makefile	2010-02-16 00:02:46.729003262 +0100
+++ linux-2.6/fs/quota/Makefile	2010-02-16 00:25:05.970004101 +0100
@@ -3,3 +3,4 @@ obj-$(CONFIG_QFMT_V1)		+= quota_v1.o
 obj-$(CONFIG_QFMT_V2)		+= quota_v2.o
 obj-$(CONFIG_QUOTA_TREE)	+= quota_tree.o
 obj-$(CONFIG_QUOTACTL)		+= quota.o
+obj-$(CONFIG_QUOTA_NETLINK_INTERFACE)	+= netlink.o
Index: linux-2.6/fs/quota/netlink.c
===================================================================
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ linux-2.6/fs/quota/netlink.c	2010-02-16 00:25:05.970004101 +0100
@@ -0,0 +1,95 @@
+
+#include <linux/cred.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/quotaops.h>
+#include <linux/sched.h>
+#include <net/netlink.h>
+#include <net/genetlink.h>
+
+/* Netlink family structure for quota */
+static struct genl_family quota_genl_family = {
+	.id = GENL_ID_GENERATE,
+	.hdrsize = 0,
+	.name = "VFS_DQUOT",
+	.version = 1,
+	.maxattr = QUOTA_NL_A_MAX,
+};
+
+/**
+ * quota_send_warning - Send warning to userspace about exceeded quota
+ * @type: The quota type: USRQQUOTA, GRPQUOTA,...
+ * @id: The user or group id of the quota that was exceeded
+ * @dev: The device on which the fs is mounted (sb->s_dev)
+ * @warntype: The type of the warning: QUOTA_NL_...
+ *
+ * This can be used by filesystems (including those which don't use
+ * dquot) to send a message to userspace relating to quota limits.
+ *
+ */
+
+void quota_send_warning(short type, unsigned int id, dev_t dev,
+			const char warntype)
+{
+	static atomic_t seq;
+	struct sk_buff *skb;
+	void *msg_head;
+	int ret;
+	int msg_size = 4 * nla_total_size(sizeof(u32)) +
+		       2 * nla_total_size(sizeof(u64));
+
+	/* We have to allocate using GFP_NOFS as we are called from a
+	 * filesystem performing write and thus further recursion into
+	 * the fs to free some data could cause deadlocks. */
+	skb = genlmsg_new(msg_size, GFP_NOFS);
+	if (!skb) {
+		printk(KERN_ERR
+		  "VFS: Not enough memory to send quota warning.\n");
+		return;
+	}
+	msg_head = genlmsg_put(skb, 0, atomic_add_return(1, &seq),
+			&quota_genl_family, 0, QUOTA_NL_C_WARNING);
+	if (!msg_head) {
+		printk(KERN_ERR
+		  "VFS: Cannot store netlink header in quota warning.\n");
+		goto err_out;
+	}
+	ret = nla_put_u32(skb, QUOTA_NL_A_QTYPE, type);
+	if (ret)
+		goto attr_err_out;
+	ret = nla_put_u64(skb, QUOTA_NL_A_EXCESS_ID, id);
+	if (ret)
+		goto attr_err_out;
+	ret = nla_put_u32(skb, QUOTA_NL_A_WARNING, warntype);
+	if (ret)
+		goto attr_err_out;
+	ret = nla_put_u32(skb, QUOTA_NL_A_DEV_MAJOR, MAJOR(dev));
+	if (ret)
+		goto attr_err_out;
+	ret = nla_put_u32(skb, QUOTA_NL_A_DEV_MINOR, MINOR(dev));
+	if (ret)
+		goto attr_err_out;
+	ret = nla_put_u64(skb, QUOTA_NL_A_CAUSED_ID, current_uid());
+	if (ret)
+		goto attr_err_out;
+	genlmsg_end(skb, msg_head);
+
+	genlmsg_multicast(skb, 0, quota_genl_family.id, GFP_NOFS);
+	return;
+attr_err_out:
+	printk(KERN_ERR "VFS: Not enough space to compose quota message!\n");
+err_out:
+	kfree_skb(skb);
+}
+EXPORT_SYMBOL(quota_send_warning);
+
+static int __init quota_init(void)
+{
+	if (genl_register_family(&quota_genl_family) != 0)
+		printk(KERN_ERR
+		       "VFS: Failed to create quota netlink interface.\n");
+	return 0;
+};
+
+module_init(quota_init);
Index: linux-2.6/fs/quota/quota.c
===================================================================
--- linux-2.6.orig/fs/quota/quota.c	2010-02-16 00:24:58.589255532 +0100
+++ linux-2.6/fs/quota/quota.c	2010-02-16 00:25:05.979006127 +0100
@@ -19,8 +19,6 @@
 #include <linux/quotaops.h>
 #include <linux/types.h>
 #include <linux/writeback.h>
-#include <net/netlink.h>
-#include <net/genetlink.h>
 
 static int check_quotactl_permission(struct super_block *sb, int type, int cmd,
 				     qid_t id)
@@ -458,94 +456,3 @@ asmlinkage long sys32_quotactl(unsigned 
 	return ret;
 }
 #endif
-
-
-#ifdef CONFIG_QUOTA_NETLINK_INTERFACE
-
-/* Netlink family structure for quota */
-static struct genl_family quota_genl_family = {
-	.id = GENL_ID_GENERATE,
-	.hdrsize = 0,
-	.name = "VFS_DQUOT",
-	.version = 1,
-	.maxattr = QUOTA_NL_A_MAX,
-};
-
-/**
- * quota_send_warning - Send warning to userspace about exceeded quota
- * @type: The quota type: USRQQUOTA, GRPQUOTA,...
- * @id: The user or group id of the quota that was exceeded
- * @dev: The device on which the fs is mounted (sb->s_dev)
- * @warntype: The type of the warning: QUOTA_NL_...
- *
- * This can be used by filesystems (including those which don't use
- * dquot) to send a message to userspace relating to quota limits.
- *
- */
-
-void quota_send_warning(short type, unsigned int id, dev_t dev,
-			const char warntype)
-{
-	static atomic_t seq;
-	struct sk_buff *skb;
-	void *msg_head;
-	int ret;
-	int msg_size = 4 * nla_total_size(sizeof(u32)) +
-		       2 * nla_total_size(sizeof(u64));
-
-	/* We have to allocate using GFP_NOFS as we are called from a
-	 * filesystem performing write and thus further recursion into
-	 * the fs to free some data could cause deadlocks. */
-	skb = genlmsg_new(msg_size, GFP_NOFS);
-	if (!skb) {
-		printk(KERN_ERR
-		  "VFS: Not enough memory to send quota warning.\n");
-		return;
-	}
-	msg_head = genlmsg_put(skb, 0, atomic_add_return(1, &seq),
-			&quota_genl_family, 0, QUOTA_NL_C_WARNING);
-	if (!msg_head) {
-		printk(KERN_ERR
-		  "VFS: Cannot store netlink header in quota warning.\n");
-		goto err_out;
-	}
-	ret = nla_put_u32(skb, QUOTA_NL_A_QTYPE, type);
-	if (ret)
-		goto attr_err_out;
-	ret = nla_put_u64(skb, QUOTA_NL_A_EXCESS_ID, id);
-	if (ret)
-		goto attr_err_out;
-	ret = nla_put_u32(skb, QUOTA_NL_A_WARNING, warntype);
-	if (ret)
-		goto attr_err_out;
-	ret = nla_put_u32(skb, QUOTA_NL_A_DEV_MAJOR, MAJOR(dev));
-	if (ret)
-		goto attr_err_out;
-	ret = nla_put_u32(skb, QUOTA_NL_A_DEV_MINOR, MINOR(dev));
-	if (ret)
-		goto attr_err_out;
-	ret = nla_put_u64(skb, QUOTA_NL_A_CAUSED_ID, current_uid());
-	if (ret)
-		goto attr_err_out;
-	genlmsg_end(skb, msg_head);
-
-	genlmsg_multicast(skb, 0, quota_genl_family.id, GFP_NOFS);
-	return;
-attr_err_out:
-	printk(KERN_ERR "VFS: Not enough space to compose quota message!\n");
-err_out:
-	kfree_skb(skb);
-}
-EXPORT_SYMBOL(quota_send_warning);
-
-static int __init quota_init(void)
-{
-	if (genl_register_family(&quota_genl_family) != 0)
-		printk(KERN_ERR
-		       "VFS: Failed to create quota netlink interface.\n");
-	return 0;
-};
-
-module_init(quota_init);
-#endif
-

[PATCH 09/10] quota: split out compat_sys_quotactl support from quota.c

[Christoph Hellwig]

[-- Attachment #1: split-compat --]
[-- Type: text/plain, Size: 8626 bytes --]

Instead of adding ifdefs just split it into a new file.

Signed-off-by: Christoph Hellwig <hch@lst.de>

Index: linux-2.6/fs/quota/Kconfig
===================================================================
--- linux-2.6.orig/fs/quota/Kconfig	2010-02-11 16:54:42.891004202 +0100
+++ linux-2.6/fs/quota/Kconfig	2010-02-16 00:25:09.291253507 +0100
@@ -59,3 +59,8 @@ config QUOTACTL
 	bool
 	depends on XFS_QUOTA || QUOTA
 	default y
+
+config QUOTACTL_COMPAT
+	bool
+	depends on QUOTACTL && COMPAT_FOR_U64_ALIGNMENT
+	default y
Index: linux-2.6/fs/quota/Makefile
===================================================================
--- linux-2.6.orig/fs/quota/Makefile	2010-02-16 00:25:05.970004101 +0100
+++ linux-2.6/fs/quota/Makefile	2010-02-16 00:25:09.292297927 +0100
@@ -3,4 +3,5 @@ obj-$(CONFIG_QFMT_V1)		+= quota_v1.o
 obj-$(CONFIG_QFMT_V2)		+= quota_v2.o
 obj-$(CONFIG_QUOTA_TREE)	+= quota_tree.o
 obj-$(CONFIG_QUOTACTL)		+= quota.o
+obj-$(CONFIG_QUOTACTL_COMPAT)	+= compat.o
 obj-$(CONFIG_QUOTA_NETLINK_INTERFACE)	+= netlink.o
Index: linux-2.6/fs/quota/compat.c
===================================================================
--- /dev/null	1970-01-01 00:00:00.000000000 +0000
+++ linux-2.6/fs/quota/compat.c	2010-02-16 00:25:09.301004031 +0100
@@ -0,0 +1,118 @@
+
+#include <linux/syscalls.h>
+#include <linux/compat.h>
+#include <linux/quotaops.h>
+
+/*
+ * This code works only for 32 bit quota tools over 64 bit OS (x86_64, ia64)
+ * and is necessary due to alignment problems.
+ */
+struct compat_if_dqblk {
+	compat_u64 dqb_bhardlimit;
+	compat_u64 dqb_bsoftlimit;
+	compat_u64 dqb_curspace;
+	compat_u64 dqb_ihardlimit;
+	compat_u64 dqb_isoftlimit;
+	compat_u64 dqb_curinodes;
+	compat_u64 dqb_btime;
+	compat_u64 dqb_itime;
+	compat_uint_t dqb_valid;
+};
+
+/* XFS structures */
+struct compat_fs_qfilestat {
+	compat_u64 dqb_bhardlimit;
+	compat_u64 qfs_nblks;
+	compat_uint_t qfs_nextents;
+};
+
+struct compat_fs_quota_stat {
+	__s8		qs_version;
+	__u16		qs_flags;
+	__s8		qs_pad;
+	struct compat_fs_qfilestat	qs_uquota;
+	struct compat_fs_qfilestat	qs_gquota;
+	compat_uint_t	qs_incoredqs;
+	compat_int_t	qs_btimelimit;
+	compat_int_t	qs_itimelimit;
+	compat_int_t	qs_rtbtimelimit;
+	__u16		qs_bwarnlimit;
+	__u16		qs_iwarnlimit;
+};
+
+asmlinkage long sys32_quotactl(unsigned int cmd, const char __user *special,
+						qid_t id, void __user *addr)
+{
+	unsigned int cmds;
+	struct if_dqblk __user *dqblk;
+	struct compat_if_dqblk __user *compat_dqblk;
+	struct fs_quota_stat __user *fsqstat;
+	struct compat_fs_quota_stat __user *compat_fsqstat;
+	compat_uint_t data;
+	u16 xdata;
+	long ret;
+
+	cmds = cmd >> SUBCMDSHIFT;
+
+	switch (cmds) {
+	case Q_GETQUOTA:
+		dqblk = compat_alloc_user_space(sizeof(struct if_dqblk));
+		compat_dqblk = addr;
+		ret = sys_quotactl(cmd, special, id, dqblk);
+		if (ret)
+			break;
+		if (copy_in_user(compat_dqblk, dqblk, sizeof(*compat_dqblk)) ||
+			get_user(data, &dqblk->dqb_valid) ||
+			put_user(data, &compat_dqblk->dqb_valid))
+			ret = -EFAULT;
+		break;
+	case Q_SETQUOTA:
+		dqblk = compat_alloc_user_space(sizeof(struct if_dqblk));
+		compat_dqblk = addr;
+		ret = -EFAULT;
+		if (copy_in_user(dqblk, compat_dqblk, sizeof(*compat_dqblk)) ||
+			get_user(data, &compat_dqblk->dqb_valid) ||
+			put_user(data, &dqblk->dqb_valid))
+			break;
+		ret = sys_quotactl(cmd, special, id, dqblk);
+		break;
+	case Q_XGETQSTAT:
+		fsqstat = compat_alloc_user_space(sizeof(struct fs_quota_stat));
+		compat_fsqstat = addr;
+		ret = sys_quotactl(cmd, special, id, fsqstat);
+		if (ret)
+			break;
+		ret = -EFAULT;
+		/* Copying qs_version, qs_flags, qs_pad */
+		if (copy_in_user(compat_fsqstat, fsqstat,
+			offsetof(struct compat_fs_quota_stat, qs_uquota)))
+			break;
+		/* Copying qs_uquota */
+		if (copy_in_user(&compat_fsqstat->qs_uquota,
+			&fsqstat->qs_uquota,
+			sizeof(compat_fsqstat->qs_uquota)) ||
+			get_user(data, &fsqstat->qs_uquota.qfs_nextents) ||
+			put_user(data, &compat_fsqstat->qs_uquota.qfs_nextents))
+			break;
+		/* Copying qs_gquota */
+		if (copy_in_user(&compat_fsqstat->qs_gquota,
+			&fsqstat->qs_gquota,
+			sizeof(compat_fsqstat->qs_gquota)) ||
+			get_user(data, &fsqstat->qs_gquota.qfs_nextents) ||
+			put_user(data, &compat_fsqstat->qs_gquota.qfs_nextents))
+			break;
+		/* Copying the rest */
+		if (copy_in_user(&compat_fsqstat->qs_incoredqs,
+			&fsqstat->qs_incoredqs,
+			sizeof(struct compat_fs_quota_stat) -
+			offsetof(struct compat_fs_quota_stat, qs_incoredqs)) ||
+			get_user(xdata, &fsqstat->qs_iwarnlimit) ||
+			put_user(xdata, &compat_fsqstat->qs_iwarnlimit))
+			break;
+		ret = 0;
+		break;
+	default:
+		ret = sys_quotactl(cmd, special, id, addr);
+	}
+	return ret;
+}
Index: linux-2.6/fs/quota/quota.c
===================================================================
--- linux-2.6.orig/fs/quota/quota.c	2010-02-16 00:25:05.979006127 +0100
+++ linux-2.6/fs/quota/quota.c	2010-02-16 00:25:09.312256301 +0100
@@ -10,7 +10,6 @@
 #include <linux/slab.h>
 #include <asm/current.h>
 #include <asm/uaccess.h>
-#include <linux/compat.h>
 #include <linux/kernel.h>
 #include <linux/security.h>
 #include <linux/syscalls.h>
@@ -340,119 +339,3 @@ SYSCALL_DEFINE4(quotactl, unsigned int, 
 	drop_super(sb);
 	return ret;
 }
-
-#if defined(CONFIG_COMPAT_FOR_U64_ALIGNMENT)
-/*
- * This code works only for 32 bit quota tools over 64 bit OS (x86_64, ia64)
- * and is necessary due to alignment problems.
- */
-struct compat_if_dqblk {
-	compat_u64 dqb_bhardlimit;
-	compat_u64 dqb_bsoftlimit;
-	compat_u64 dqb_curspace;
-	compat_u64 dqb_ihardlimit;
-	compat_u64 dqb_isoftlimit;
-	compat_u64 dqb_curinodes;
-	compat_u64 dqb_btime;
-	compat_u64 dqb_itime;
-	compat_uint_t dqb_valid;
-};
-
-/* XFS structures */
-struct compat_fs_qfilestat {
-	compat_u64 dqb_bhardlimit;
-	compat_u64 qfs_nblks;
-	compat_uint_t qfs_nextents;
-};
-
-struct compat_fs_quota_stat {
-	__s8		qs_version;
-	__u16		qs_flags;
-	__s8		qs_pad;
-	struct compat_fs_qfilestat	qs_uquota;
-	struct compat_fs_qfilestat	qs_gquota;
-	compat_uint_t	qs_incoredqs;
-	compat_int_t	qs_btimelimit;
-	compat_int_t	qs_itimelimit;
-	compat_int_t	qs_rtbtimelimit;
-	__u16		qs_bwarnlimit;
-	__u16		qs_iwarnlimit;
-};
-
-asmlinkage long sys32_quotactl(unsigned int cmd, const char __user *special,
-						qid_t id, void __user *addr)
-{
-	unsigned int cmds;
-	struct if_dqblk __user *dqblk;
-	struct compat_if_dqblk __user *compat_dqblk;
-	struct fs_quota_stat __user *fsqstat;
-	struct compat_fs_quota_stat __user *compat_fsqstat;
-	compat_uint_t data;
-	u16 xdata;
-	long ret;
-
-	cmds = cmd >> SUBCMDSHIFT;
-
-	switch (cmds) {
-	case Q_GETQUOTA:
-		dqblk = compat_alloc_user_space(sizeof(struct if_dqblk));
-		compat_dqblk = addr;
-		ret = sys_quotactl(cmd, special, id, dqblk);
-		if (ret)
-			break;
-		if (copy_in_user(compat_dqblk, dqblk, sizeof(*compat_dqblk)) ||
-			get_user(data, &dqblk->dqb_valid) ||
-			put_user(data, &compat_dqblk->dqb_valid))
-			ret = -EFAULT;
-		break;
-	case Q_SETQUOTA:
-		dqblk = compat_alloc_user_space(sizeof(struct if_dqblk));
-		compat_dqblk = addr;
-		ret = -EFAULT;
-		if (copy_in_user(dqblk, compat_dqblk, sizeof(*compat_dqblk)) ||
-			get_user(data, &compat_dqblk->dqb_valid) ||
-			put_user(data, &dqblk->dqb_valid))
-			break;
-		ret = sys_quotactl(cmd, special, id, dqblk);
-		break;
-	case Q_XGETQSTAT:
-		fsqstat = compat_alloc_user_space(sizeof(struct fs_quota_stat));
-		compat_fsqstat = addr;
-		ret = sys_quotactl(cmd, special, id, fsqstat);
-		if (ret)
-			break;
-		ret = -EFAULT;
-		/* Copying qs_version, qs_flags, qs_pad */
-		if (copy_in_user(compat_fsqstat, fsqstat,
-			offsetof(struct compat_fs_quota_stat, qs_uquota)))
-			break;
-		/* Copying qs_uquota */
-		if (copy_in_user(&compat_fsqstat->qs_uquota,
-			&fsqstat->qs_uquota,
-			sizeof(compat_fsqstat->qs_uquota)) ||
-			get_user(data, &fsqstat->qs_uquota.qfs_nextents) ||
-			put_user(data, &compat_fsqstat->qs_uquota.qfs_nextents))
-			break;
-		/* Copying qs_gquota */
-		if (copy_in_user(&compat_fsqstat->qs_gquota,
-			&fsqstat->qs_gquota,
-			sizeof(compat_fsqstat->qs_gquota)) ||
-			get_user(data, &fsqstat->qs_gquota.qfs_nextents) ||
-			put_user(data, &compat_fsqstat->qs_gquota.qfs_nextents))
-			break;
-		/* Copying the rest */
-		if (copy_in_user(&compat_fsqstat->qs_incoredqs,
-			&fsqstat->qs_incoredqs,
-			sizeof(struct compat_fs_quota_stat) -
-			offsetof(struct compat_fs_quota_stat, qs_incoredqs)) ||
-			get_user(xdata, &fsqstat->qs_iwarnlimit) ||
-			put_user(xdata, &compat_fsqstat->qs_iwarnlimit))
-			break;
-		ret = 0;
-		break;
-	default:
-		ret = sys_quotactl(cmd, special, id, addr);
-	}
-	return ret;
-}
-#endif

[PATCH 10/10] quota: drop permission checks from xfs_fs_set_xstate/xfs_fs_set_xquota

[Christoph Hellwig]

[-- Attachment #1: xfs-quota-drop-permission-checks --]
[-- Type: text/plain, Size: 850 bytes --]

We already do these checks in the generic code.

Signed-off-by: Christoph Hellwig <hch@lst.de>

Index: linux-2.6/fs/xfs/linux-2.6/xfs_quotaops.c
===================================================================
--- linux-2.6.orig/fs/xfs/linux-2.6/xfs_quotaops.c	2010-02-16 00:15:27.709004380 +0100
+++ linux-2.6/fs/xfs/linux-2.6/xfs_quotaops.c	2010-02-16 00:25:10.992007173 +0100
@@ -68,8 +68,6 @@ xfs_fs_set_xstate(
 		return -EROFS;
 	if (op != Q_XQUOTARM && !XFS_IS_QUOTA_RUNNING(mp))
 		return -ENOSYS;
-	if (!capable(CAP_SYS_ADMIN))
-		return -EPERM;
 
 	if (uflags & XFS_QUOTA_UDQ_ACCT)
 		flags |= XFS_UQUOTA_ACCT;
@@ -130,8 +128,6 @@ xfs_fs_set_xquota(
 		return -ENOSYS;
 	if (!XFS_IS_QUOTA_ON(mp))
 		return -ESRCH;
-	if (!capable(CAP_SYS_ADMIN))
-		return -EPERM;
 
 	return -xfs_qm_scall_setqlim(mp, id, xfs_quota_type(type), fdq);
 }

Re: [PATCH 00/10] quotactl fixed and cleanups

[Christoph Hellwig]

err, the subject should read fixes of course.

Re: [PATCH 00/10] quotactl fixed and cleanups

[Steven Whitehouse]

Hi,

On Tue, 2010-02-16 at 03:44 -0500, Christoph Hellwig wrote:
> This is a first large batch of refactoring the generic quotactl code.
> I started looking at this for merging the FS interfaces for "VFS" and "XFS"
> style quotas now that we grow more filesystems wanting to support quota
> in a more advanced way than the generic implementation can, e.g. GFS2
> and cifs.  There will be another couple of patches do do the actual
> work which are not quite ready, but this is a large and useful enough batch
> to get review and possibly included first.

Looks good from a GFS2 PoV, so:

Acked-by: Steven Whitehouse <swhiteho@redhat.com>

Steve.

Re: [PATCH 00/10] quotactl fixed and cleanups

[Jan Kara]

On Tue 16-02-10 03:44:46, Christoph Hellwig wrote:
> This is a first large batch of refactoring the generic quotactl code.
> I started looking at this for merging the FS interfaces for "VFS" and "XFS"
> style quotas now that we grow more filesystems wanting to support quota
> in a more advanced way than the generic implementation can, e.g. GFS2
> and cifs.  There will be another couple of patches do do the actual
> work which are not quite ready, but this is a large and useful enough batch
> to get review and possibly included first.
  Thanks for the cleanups. Upto a few fixed typos and whitespace errors
I've merged your patchset into my tree.
  As a side note, OCFS2 implements XFS-style clustered quotas using current
VFS quota subsystem (and quota file format) so my naive feeling is that at
least GFS2 should fit in there as well. But maybe I'm wrong.

									Honza
-- 
Jan Kara <jack@suse.cz>
SUSE Labs, CR

Re: [PATCH 00/10] quotactl fixed and cleanups

[Christoph Hellwig]

On Tue, Feb 16, 2010 at 07:36:28PM +0100, Jan Kara wrote:
>   Thanks for the cleanups. Upto a few fixed typos and whitespace errors
> I've merged your patchset into my tree.
>   As a side note, OCFS2 implements XFS-style clustered quotas using current
> VFS quota subsystem (and quota file format) so my naive feeling is that at
> least GFS2 should fit in there as well. But maybe I'm wrong.

The file format is one big difference.  The other is that having the
quota code in the filesystem allows much nicer integration with the
transaction code.  Anyway, my next step is to support both the
current "VFS" and the "XFS" quota interface independent of the
underlying implementation, at least for the runtime calls.  The
quota on/off bits are a bit too different, but it might be a good
idea to handle those everywhere primarily via mount options and
deprecate most of the old calls, but keep supporting them for a long
time.  After that I plan to look a bit more in the quota implementation
and look for sharing opportunities, but it might take a while until I
get to that.

Re: [PATCH 00/10] quotactl fixed and cleanups

[Jan Kara]

On Tue 16-02-10 14:12:07, Christoph Hellwig wrote:
> On Tue, Feb 16, 2010 at 07:36:28PM +0100, Jan Kara wrote:
> >   Thanks for the cleanups. Upto a few fixed typos and whitespace errors
> > I've merged your patchset into my tree.
> >   As a side note, OCFS2 implements XFS-style clustered quotas using current
> > VFS quota subsystem (and quota file format) so my naive feeling is that at
> > least GFS2 should fit in there as well. But maybe I'm wrong.
> 
> The file format is one big difference.  The other is that having the
> quota code in the filesystem allows much nicer integration with the
> transaction code.  Anyway, my next step is to support both the
> current "VFS" and the "XFS" quota interface independent of the
> underlying implementation, at least for the runtime calls.  The
> quota on/off bits are a bit too different, but it might be a good
> idea to handle those everywhere primarily via mount options and
> deprecate most of the old calls, but keep supporting them for a long
> time.  After that I plan to look a bit more in the quota implementation
> and look for sharing opportunities, but it might take a while until I
> get to that.
  The semantics I've chosen for OCFS2 is that if "USRQUOTA" filesystem
feature is enabled, we always do accounting of users' usage (as this is
essntially filesystem metadata). 'usrquota' mount option is just ignored
and used only to make life easier to quota-tools (so that they don't have
to parse superblock to find whether quota is supported or not). Enforcement
is enabled / disabled by quotactl call.
  I'd eventually love to convert ext3/4 to this behavior as well (and move
quota files to be invisible "system" inodes) so if XFS would be consistent
with this, it would be nice.

								Honza
-- 
Jan Kara <jack@suse.cz>
SUSE Labs, CR

Re: [PATCH 00/10] quotactl fixed and cleanups

[Christoph Hellwig]

On Tue, Feb 16, 2010 at 10:26:34PM +0100, Jan Kara wrote:
>   The semantics I've chosen for OCFS2 is that if "USRQUOTA" filesystem
> feature is enabled, we always do accounting of users' usage (as this is
> essntially filesystem metadata). 'usrquota' mount option is just ignored
> and used only to make life easier to quota-tools (so that they don't have
> to parse superblock to find whether quota is supported or not). Enforcement
> is enabled / disabled by quotactl call.
>   I'd eventually love to convert ext3/4 to this behavior as well (and move
> quota files to be invisible "system" inodes) so if XFS would be consistent
> with this, it would be nice.

XFS is almost but not quite consistant with that.  XFS has mount
options for accounting and enforcement, but no superblock bit yet.
Accounting always needs to be enabled at mount time, and enforcement
can be enabled/disabled with quotactl / xfs_quota in addition to the
mount option.  We have been thinking about optionally also adding the
superblock flag as that would make a lof of things easier, especially
for quotas on the root filesystem.

Re: [PATCH 00/10] quotactl fixed and cleanups

[Christoph Hellwig]

On Tue, Feb 16, 2010 at 07:36:28PM +0100, Jan Kara wrote:
>   Thanks for the cleanups. Upto a few fixed typos and whitespace errors
> I've merged your patchset into my tree.

Where is your tree located?  I can't find anything with these patches on
git.kernel.org.

Re: [PATCH 00/10] quotactl fixed and cleanups

[Jan Kara]

On Wed 17-02-10 14:37:19, Christoph Hellwig wrote:
> On Tue, Feb 16, 2010 at 07:36:28PM +0100, Jan Kara wrote:
> >   Thanks for the cleanups. Upto a few fixed typos and whitespace errors
> > I've merged your patchset into my tree.
> 
> Where is your tree located?  I can't find anything with these patches on
> git.kernel.org.
  Oops, sorry, I forgot to push. It's at
git.kernel.org/linux/kernel/git/jack/linux-fs-2.6.git for_next

								Honza
-- 
Jan Kara <jack@suse.cz>
SUSE Labs, CR

Re: [PATCH 00/10] quotactl fixed and cleanups

[Alex Elder]

On Tue, 2010-02-16 at 03:44 -0500, Christoph Hellwig wrote:
> This is a first large batch of refactoring the generic quotactl code.
> I started looking at this for merging the FS interfaces for "VFS" and "XFS"
> style quotas now that we grow more filesystems wanting to support quota
> in a more advanced way than the generic implementation can, e.g. GFS2
> and cifs.  There will be another couple of patches do do the actual
> work which are not quite ready, but this is a large and useful enough batch
> to get review and possibly included first.
> --
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Whole series looks good to me.  I know it's late, but...

Acked-by: Alex Elder <aelder@sgi.com>