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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: Steven Whitehouse <swhiteho@redhat.com>
This commit is contained in:
Steven Whitehouse 2009-09-28 12:35:17 +01:00
parent e285c10036
commit 86e931a35e
4 changed files with 114 additions and 85 deletions
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2
fs/quota/Kconfig
View File

@ -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,

93
fs/quota/dquot.c
View File

@ -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 @@ static void send_warning(const struct dquot *dquot, const char warntype)
*/
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);

93
fs/quota/quota.c
View File

@ -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

11
include/linux/quota.h
View File

@ -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 */