The patch titled
send-quota-messages-via-netlink fix
has been removed from the -mm tree. Its filename was
send-quota-messages-via-netlink-fix.patch
This patch was dropped because it was folded into quota-send-messages-via-netlink.patch
------------------------------------------------------
Subject: send-quota-messages-via-netlink fix
From: Jan Kara <jack@xxxxxxx>
Add documentation of quota netlink interface, fix possible race in handling
of packet numbers, add a comment about GFP_NOFS allocation.
Signed-off-by: Jan Kara <jack@xxxxxxx>
Cc: Randy Dunlap <randy.dunlap@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
Documentation/filesystems/quota.txt | 59 ++++++++++++++++++++++++++
fs/dquot.c | 8 ++-
2 files changed, 65 insertions(+), 2 deletions(-)
diff -puN /dev/null Documentation/filesystems/quota.txt
--- /dev/null
+++ a/Documentation/filesystems/quota.txt
@@ -0,0 +1,59 @@
+
+Quota subsystem
+===============
+
+Quota subsystem allows system administrator to set limits on used space and
+number of used inodes (inode is a filesystem structure which is associated
+with each file or directory) for users and/or groups. For both used space and
+number of used inodes there are actually two limits. The first one is called
+softlimit and the second one hardlimit. An user can never exceed a hardlimit
+for any resource. User is allowed to exceed softlimit but only for limited
+period of time. This period is called "grace period" or "grace time". When
+grace time is over, user is not able to allocate more space/inodes until he
+frees enough of them to get below softlimit.
+
+Quota limits (and amount of grace time) are set independently for each
+filesystem.
+
+For more details about quota design, see the documentation in quota-tools package
+(http://sourceforge.net/projects/linuxquota).
+
+Quota netlink interface
+=======================
+When user exceeds a softlimit, runs out of grace time or reaches hardlimit,
+quota subsystem traditionally printed a message to the controlling terminal of
+the process which caused the excess. This method has the disadvantage that
+when user is using a graphical desktop he usually cannot see the message.
+Thus quota netlink interface has been designed to pass information about
+the above events to userspace. There they can be captured by an application
+and processed accordingly.
+
+The interface uses generic netlink framework (see
+http://lwn.net/Articles/208755/ and http://people.suug.ch/~tgr/libnl/ for more
+details about this layer). The name of the quota generic netlink interface
+is "VFS_DQUOT". Definitions of constants below are in <linux/quota.h>.
+ Currently, the interface supports only one message type QUOTA_NL_C_WARNING.
+This command is used to send a notification about any of the above mentioned
+events. Each message has six attributes. These are (type of the argument is
+in braces):
+ QUOTA_NL_A_QTYPE (u32)
+ - type of quota beging exceeded (one of USRQUOTA, GRPQUOTA)
+ QUOTA_NL_A_EXCESS_ID (u64)
+ - UID/GID (depends on quota type) of user / group whose limit
+ is being exceeded.
+ QUOTA_NL_A_CAUSED_ID (u64)
+ - UID of a user who caused the event
+ QUOTA_NL_A_WARNING (u32)
+ - what kind of limit is exceeded:
+ QUOTA_NL_IHARDWARN - inode hardlimit
+ QUOTA_NL_ISOFTLONGWARN - inode softlimit is exceeded longer
+ than given grace period
+ QUOTA_NL_ISOFTWARN - inode softlimit
+ QUOTA_NL_BHARDWARN - space (block) hardlimit
+ QUOTA_NL_BSOFTLONGWARN - space (block) softlimit is exceeded
+ longer than given grace period.
+ QUOTA_NL_BSOFTWARN - space (block) softlimit
+ QUOTA_NL_A_DEV_MAJOR (u32)
+ - major number of a device with the affected filesystem
+ QUOTA_NL_A_DEV_MINOR (u32)
+ - minor number of a device with the affected filesystem
diff -puN fs/dquot.c~send-quota-messages-via-netlink-fix fs/dquot.c
--- a/fs/dquot.c~send-quota-messages-via-netlink-fix
+++ a/fs/dquot.c
@@ -910,18 +910,22 @@ static struct genl_family quota_genl_fam
/* Send warning to userspace about user which exceeded quota */
static void send_warning(const struct dquot *dquot, const char warntype)
{
- static unsigned long seq;
+ static atomic_t seq;
struct sk_buff *skb;
void *msg_head;
int ret;
+ /* 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(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);
+ msg_head = genlmsg_put(skb, 0, atomic_add_return(1, &seq),
+ "a_genl_family, 0, QUOTA_NL_C_WARNING);
if (!msg_head) {
printk(KERN_ERR
"VFS: Cannot store netlink header in quota warning.\n");
_
Patches currently in -mm which might be from jack@xxxxxxx are
quota-send-messages-via-netlink.patch
send-quota-messages-via-netlink-fix.patch
send-quota-messages-via-netlink-fix-fix.patch
udf-code-style-fixup-v3.patch
jbd-config_jbd_debug-cannot-create-proc-entry.patch
jbd-config_jbd_debug-cannot-create-proc-entry-fix.patch
jbd-fix-commit-code-to-properly-abort-journal.patch
-
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