[PATCH] Quota netlink interface
From: Jan Kara
Date: Mon Jun 18 2007 - 08:01:50 EST
Hello,
I've written a patch implementing quota netlink interface. Whenever some
event happens (like user exceeding softlimit), a message is sent to
userpace. Then, in userspace we can decide what to do with the message -
print it to console, show a dialog or whatever... I've also written a new
daemon that listens to netlink and sends the received message to DBus and/or
to the console the user has last written to.
If somebody is interested in trying it out, he can checkout latest
quota-tools CVS and I can provide him with the modified libnl providing
better support for generic netlink handling.
Honza
--
Jan Kara <jack@xxxxxxx>
SuSE CR Labs
Implement sending of quota messages via netlink interface. The advantage is
that in userspace we can better decide what to do with the message - for
example display a dialogue in your X session or just write the message to the
console. As a bonus, we can get rid of problems with console locking deep
inside filesystem code once we remove the old printing mechanism.
Signed-off-by: Jan Kara <jack@xxxxxxx>
diff -rupX /home/jack/.kerndiffexclude linux-2.6.22-rc5/fs/dquot.c linux-2.6.22-rc5-1-quota_messages/fs/dquot.c
--- linux-2.6.22-rc5/fs/dquot.c 2007-06-18 12:12:38.000000000 +0200
+++ linux-2.6.22-rc5-1-quota_messages/fs/dquot.c 2007-06-18 12:13:26.000000000 +0200
@@ -79,6 +79,10 @@
#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>
@@ -818,6 +822,7 @@ static inline void dquot_decr_space(stru
clear_bit(DQ_BLKS_B, &dquot->dq_flags);
}
+#ifdef CONFIG_PRINT_QUOTA_WARNING
static int flag_print_warnings = 1;
static inline int need_print_warning(struct dquot *dquot)
@@ -834,22 +839,15 @@ static inline int need_print_warning(str
return 0;
}
-/* Values of warnings */
-#define NOWARN 0
-#define IHARDWARN 1
-#define ISOFTLONGWARN 2
-#define ISOFTWARN 3
-#define BHARDWARN 4
-#define BSOFTLONGWARN 5
-#define BSOFTWARN 6
-
/* Print warning to user which exceeded quota */
static void print_warning(struct dquot *dquot, const char warntype)
{
char *msg = NULL;
struct tty_struct *tty;
- int flag = (warntype == BHARDWARN || warntype == BSOFTLONGWARN) ? DQ_BLKS_B :
- ((warntype == IHARDWARN || warntype == ISOFTLONGWARN) ? DQ_INODES_B : 0);
+ int flag = (warntype == QUOTA_NL_BHARDWARN ||
+ warntype == QUOTA_NL_BSOFTLONGWARN) ? DQ_BLKS_B :
+ ((warntype == QUOTA_NL_IHARDWARN ||
+ warntype == QUOTA_NL_ISOFTLONGWARN) ? DQ_INODES_B : 0);
if (!need_print_warning(dquot) || (flag && test_and_set_bit(flag, &dquot->dq_flags)))
return;
@@ -859,28 +857,28 @@ static void print_warning(struct dquot *
if (!tty)
goto out_lock;
tty_write_message(tty, dquot->dq_sb->s_id);
- if (warntype == ISOFTWARN || warntype == BSOFTWARN)
+ if (warntype == QUOTA_NL_ISOFTWARN || warntype == QUOTA_NL_BSOFTWARN)
tty_write_message(tty, ": warning, ");
else
tty_write_message(tty, ": write failed, ");
tty_write_message(tty, quotatypes[dquot->dq_type]);
switch (warntype) {
- case IHARDWARN:
+ case QUOTA_NL_IHARDWARN:
msg = " file limit reached.\r\n";
break;
- case ISOFTLONGWARN:
+ case QUOTA_NL_ISOFTLONGWARN:
msg = " file quota exceeded too long.\r\n";
break;
- case ISOFTWARN:
+ case QUOTA_NL_ISOFTWARN:
msg = " file quota exceeded.\r\n";
break;
- case BHARDWARN:
+ case QUOTA_NL_BHARDWARN:
msg = " block limit reached.\r\n";
break;
- case BSOFTLONGWARN:
+ case QUOTA_NL_BSOFTLONGWARN:
msg = " block quota exceeded too long.\r\n";
break;
- case BSOFTWARN:
+ case QUOTA_NL_BSOFTWARN:
msg = " block quota exceeded.\r\n";
break;
}
@@ -888,14 +886,89 @@ static void print_warning(struct dquot *
out_lock:
mutex_unlock(&tty_mutex);
}
+#endif
+
+#ifdef CONFIG_QUOTA_NETLINK_INTERFACE
+
+/* Size of quota netlink message - actually an upperbound for buffer size */
+#define QUOTA_NL_MSG_SIZE 32
+
+/* 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 unsigned long seq;
+ struct sk_buff *skb;
+ void *msg_head;
+ int ret;
+
+ skb = genlmsg_new(QUOTA_NL_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, seq++, "a_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->user->uid);
+ if (ret)
+ goto attr_err_out;
+ genlmsg_end(skb, msg_head);
+
+ ret = genlmsg_multicast(skb, 0, quota_genl_family.id, GFP_NOFS);
+ if (ret < 0 && ret != -ESRCH)
+ printk(KERN_ERR
+ "VFS: Failed to send notification message: %d\n", ret);
+ return;
+attr_err_out:
+ printk(KERN_ERR "VFS: Failed to compose quota message: %d\n", ret);
+err_out:
+ kfree_skb(skb);
+}
+#endif
static inline void flush_warnings(struct dquot **dquots, char *warntype)
{
int i;
for (i = 0; i < MAXQUOTAS; i++)
- if (dquots[i] != NODQUOT && warntype[i] != NOWARN)
+ if (dquots[i] != NODQUOT && warntype[i] != QUOTA_NL_NOWARN) {
+#ifdef CONFIG_PRINT_QUOTA_WARNING
print_warning(dquots[i], warntype[i]);
+#endif
+#ifdef CONFIG_QUOTA_NETLINK_INTERFACE
+ send_warning(dquots[i], warntype[i]);
+#endif
+ }
}
static inline char ignore_hardlimit(struct dquot *dquot)
@@ -909,14 +982,14 @@ static inline char ignore_hardlimit(stru
/* needs dq_data_lock */
static int check_idq(struct dquot *dquot, ulong inodes, char *warntype)
{
- *warntype = NOWARN;
+ *warntype = QUOTA_NL_NOWARN;
if (inodes <= 0 || test_bit(DQ_FAKE_B, &dquot->dq_flags))
return QUOTA_OK;
if (dquot->dq_dqb.dqb_ihardlimit &&
(dquot->dq_dqb.dqb_curinodes + inodes) > dquot->dq_dqb.dqb_ihardlimit &&
!ignore_hardlimit(dquot)) {
- *warntype = IHARDWARN;
+ *warntype = QUOTA_NL_IHARDWARN;
return NO_QUOTA;
}
@@ -924,14 +997,14 @@ static int check_idq(struct dquot *dquot
(dquot->dq_dqb.dqb_curinodes + inodes) > dquot->dq_dqb.dqb_isoftlimit &&
dquot->dq_dqb.dqb_itime && get_seconds() >= dquot->dq_dqb.dqb_itime &&
!ignore_hardlimit(dquot)) {
- *warntype = ISOFTLONGWARN;
+ *warntype = QUOTA_NL_ISOFTLONGWARN;
return NO_QUOTA;
}
if (dquot->dq_dqb.dqb_isoftlimit &&
(dquot->dq_dqb.dqb_curinodes + inodes) > dquot->dq_dqb.dqb_isoftlimit &&
dquot->dq_dqb.dqb_itime == 0) {
- *warntype = ISOFTWARN;
+ *warntype = QUOTA_NL_ISOFTWARN;
dquot->dq_dqb.dqb_itime = get_seconds() + sb_dqopt(dquot->dq_sb)->info[dquot->dq_type].dqi_igrace;
}
@@ -941,7 +1014,7 @@ static int check_idq(struct dquot *dquot
/* needs dq_data_lock */
static int check_bdq(struct dquot *dquot, qsize_t space, int prealloc, char *warntype)
{
- *warntype = 0;
+ *warntype = QUOTA_NL_NOWARN;
if (space <= 0 || test_bit(DQ_FAKE_B, &dquot->dq_flags))
return QUOTA_OK;
@@ -949,7 +1022,7 @@ static int check_bdq(struct dquot *dquot
toqb(dquot->dq_dqb.dqb_curspace + space) > dquot->dq_dqb.dqb_bhardlimit &&
!ignore_hardlimit(dquot)) {
if (!prealloc)
- *warntype = BHARDWARN;
+ *warntype = QUOTA_NL_BHARDWARN;
return NO_QUOTA;
}
@@ -958,7 +1031,7 @@ static int check_bdq(struct dquot *dquot
dquot->dq_dqb.dqb_btime && get_seconds() >= dquot->dq_dqb.dqb_btime &&
!ignore_hardlimit(dquot)) {
if (!prealloc)
- *warntype = BSOFTLONGWARN;
+ *warntype = QUOTA_NL_BSOFTLONGWARN;
return NO_QUOTA;
}
@@ -966,7 +1039,7 @@ static int check_bdq(struct dquot *dquot
toqb(dquot->dq_dqb.dqb_curspace + space) > dquot->dq_dqb.dqb_bsoftlimit &&
dquot->dq_dqb.dqb_btime == 0) {
if (!prealloc) {
- *warntype = BSOFTWARN;
+ *warntype = QUOTA_NL_BSOFTWARN;
dquot->dq_dqb.dqb_btime = get_seconds() + sb_dqopt(dquot->dq_sb)->info[dquot->dq_type].dqi_bgrace;
}
else
@@ -1061,7 +1134,7 @@ out_add:
return QUOTA_OK;
}
for (cnt = 0; cnt < MAXQUOTAS; cnt++)
- warntype[cnt] = NOWARN;
+ warntype[cnt] = QUOTA_NL_NOWARN;
down_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
if (IS_NOQUOTA(inode)) { /* Now we can do reliable test... */
@@ -1107,7 +1180,7 @@ int dquot_alloc_inode(const struct inode
if (IS_NOQUOTA(inode))
return QUOTA_OK;
for (cnt = 0; cnt < MAXQUOTAS; cnt++)
- warntype[cnt] = NOWARN;
+ warntype[cnt] = QUOTA_NL_NOWARN;
down_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
if (IS_NOQUOTA(inode)) {
up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
@@ -1229,7 +1302,7 @@ int dquot_transfer(struct inode *inode,
/* Clear the arrays */
for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
transfer_to[cnt] = transfer_from[cnt] = NODQUOT;
- warntype[cnt] = NOWARN;
+ warntype[cnt] = QUOTA_NL_NOWARN;
}
down_write(&sb_dqopt(inode->i_sb)->dqptr_sem);
/* Now recheck reliably when holding dqptr_sem */
@@ -1803,6 +1876,7 @@ static ctl_table fs_dqstats_table[] = {
.mode = 0444,
.proc_handler = &proc_dointvec,
},
+#ifdef CONFIG_PRINT_QUOTA_WARNING
{
.ctl_name = FS_DQ_WARNINGS,
.procname = "warnings",
@@ -1811,6 +1885,7 @@ static ctl_table fs_dqstats_table[] = {
.mode = 0644,
.proc_handler = &proc_dointvec,
},
+#endif
{ .ctl_name = 0 },
};
@@ -1872,6 +1947,11 @@ static int __init dquot_init(void)
set_shrinker(DEFAULT_SEEKS, shrink_dqcache_memory);
+#ifdef CONFIG_QUOTA_NETLINK_INTERFACE
+ if (genl_register_family("a_genl_family) != 0)
+ printk(KERN_ERR "VFS: Failed to create quota netlink interface.\n");
+#endif
+
return 0;
}
module_init(dquot_init);
diff -rupX /home/jack/.kerndiffexclude linux-2.6.22-rc5/fs/Kconfig linux-2.6.22-rc5-1-quota_messages/fs/Kconfig
--- linux-2.6.22-rc5/fs/Kconfig 2007-06-18 12:12:37.000000000 +0200
+++ linux-2.6.22-rc5-1-quota_messages/fs/Kconfig 2007-06-18 12:14:54.000000000 +0200
@@ -537,6 +537,25 @@ config QUOTA
with the quota tools. Probably the quota support is only useful for
multi user systems. If unsure, say N.
+config QUOTA_NETLINK_INTERFACE
+ bool "Report quota messages through netlink interface"
+ depends on QUOTA
+ select NET
+ help
+ If you say Y here, quota warnings (about exceeding softlimit, reaching
+ hardlimit, etc.) will be reported through netlink interface. If unsure,
+ say Y.
+
+config PRINT_QUOTA_WARNING
+ bool "Print quota warnings to console (OBSOLETE)"
+ depends on QUOTA
+ default y
+ help
+ If you say Y here, quota warnings (about exceeding softlimit, reaching
+ hardlimit, etc.) will be printed to the process' controlling terminal.
+ Note that this behavior is currently deprecated and may go away in
+ future. Please use notification via netlink socket instead.
+
config QFMT_V1
tristate "Old quota format support"
depends on QUOTA