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Commit 86e931a3 authored by Steven Whitehouse's avatar Steven Whitehouse
Browse files

VFS: Export dquot_send_warning 



Sending a message to userspace in a generic format to warn
of events (e.g. quota exceeded) in the quota subsystem is
a generically useful feature. This patch makes some minor
changes to the send_message function from dquot.c renaming
it quota_send_message, moving it to quota.c and exporting it
for use by filesystems which do not use the dquot code.

Signed-off-by: default avatarSteven Whitehouse <swhiteho@redhat.com>
parent e285c100

fs/quota/Kconfig

+1 −1
Original line number Diff line number Diff line
@@ -17,7 +17,7 @@ config QUOTA 


config QUOTA_NETLINK_INTERFACE

	bool "Report quota messages through netlink interface"

	depends on QUOTA && NET

	depends on QUOTACTL && NET

	help

	  If you say Y here, quota warnings (about exceeding softlimit, reaching

	  hardlimit, etc.) will be reported through netlink interface. If unsure,

fs/quota/dquot.c

+9 −84
Original line number Diff line number Diff line
@@ -77,10 +77,6 @@ 
#include <linux/capability.h>

#include <linux/quotaops.h>

#include <linux/writeback.h> /* for inode_lock, oddly enough.. */

#ifdef CONFIG_QUOTA_NETLINK_INTERFACE

#include <net/netlink.h>

#include <net/genetlink.h>

#endif



#include <asm/uaccess.h>
@@ -1071,73 +1067,6 @@ static void print_warning(struct dquot *dquot, const int warntype) 
}

#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,

};



/* Send warning to userspace about user which exceeded quota */

static void send_warning(const struct dquot *dquot, 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, dquot->dq_type);

	if (ret)

		goto attr_err_out;

	ret = nla_put_u64(skb, QUOTA_NL_A_EXCESS_ID, dquot->dq_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(dquot->dq_sb->s_dev));

	if (ret)

		goto attr_err_out;

	ret = nla_put_u32(skb, QUOTA_NL_A_DEV_MINOR,

		MINOR(dquot->dq_sb->s_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);

}

#endif

/*

 * Write warnings to the console and send warning messages over netlink.

 *
@@ -1145,17 +1074,19 @@ err_out: 
 */

static void flush_warnings(struct dquot *const *dquots, char *warntype)

{

	struct dquot *dq;

	int i;



	for (i = 0; i < MAXQUOTAS; i++)

		if (dquots[i] && warntype[i] != QUOTA_NL_NOWARN &&

		    !warning_issued(dquots[i], warntype[i])) {

	for (i = 0; i < MAXQUOTAS; i++) {

		dq = dquots[i];

		if (dq && warntype[i] != QUOTA_NL_NOWARN &&

		    !warning_issued(dq, warntype[i])) {

#ifdef CONFIG_PRINT_QUOTA_WARNING

			print_warning(dquots[i], warntype[i]);

#endif

#ifdef CONFIG_QUOTA_NETLINK_INTERFACE

			send_warning(dquots[i], warntype[i]);

			print_warning(dq, warntype[i]);

#endif

			quota_send_warning(dq->dq_type, dq->dq_id,

					   dq->dq_sb->s_dev, warntype[i]);

		}

	}

}
@@ -2607,12 +2538,6 @@ static int __init dquot_init(void) 


	register_shrinker(&dqcache_shrinker);



#ifdef CONFIG_QUOTA_NETLINK_INTERFACE

	if (genl_register_family(&quota_genl_family) != 0)

		printk(KERN_ERR

		       "VFS: Failed to create quota netlink interface.\n");

#endif



	return 0;

}

module_init(dquot_init);

fs/quota/quota.c

+93 −0
Original line number Diff line number Diff line
@@ -18,6 +18,8 @@ 
#include <linux/capability.h>

#include <linux/quotaops.h>

#include <linux/types.h>

#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,
@@ -525,3 +527,94 @@ asmlinkage long sys32_quotactl(unsigned int cmd, const char __user *special, 
	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

include/linux/quota.h

+11 −0
Original line number Diff line number Diff line
@@ -376,6 +376,17 @@ static inline unsigned int dquot_generic_flag(unsigned int flags, int type) 
	return flags >> _DQUOT_STATE_FLAGS;

}



#ifdef CONFIG_QUOTA_NETLINK_INTERFACE

extern void quota_send_warning(short type, unsigned int id, dev_t dev,

			       const char warntype);

#else

static inline void quota_send_warning(short type, unsigned int id, dev_t dev,

				      const char warntype)

{

	return;

}

#endif /* CONFIG_QUOTA_NETLINK_INTERFACE */



struct quota_info {

	unsigned int flags;			/* Flags for diskquotas on this device */

	struct mutex dqio_mutex;		/* lock device while I/O in progress */