[Devel] Re: [patch 1/5][RFC - ipv4/udp checkpoint/restart] : add lookup for unhashed inode
Quoting [EMAIL PROTECTED] ([EMAIL PROTECTED]):
The socket relies on the sockfs. In some cases, the socket are orphans and
it is not possible to access them via a file descriptor, this is the case for
example for timewait sockets. Hopefully, an inode is still usable to specify
a socket. This one can be retrieved from /proc/net/tcp for orphan sockets or
from a fstat.
When a socket is created the socket inode is added to the sockfs.
Unfortunatly, this one is not stored into the hashed inode list, so
I need a helper to browse the inode list contained in the superblock
of the sockfs.
This is one solution, another solution is to stored the inode into
the hashed list when socket is created.
I assume that would be unacceptable overhead on a very busy server.
Walking all the inodes NUM_INODES(task_set) for a checkpoint could
be a real bottleneck, but at least it's only at checkpoint time.
Have you checked net-dev archives for discussions about not hashing
these inodes? I suppose at some point you'll want to ask there what the
preference is.
But certainly for now this seems the right approach.
Signed-off-by: Daniel Lezcano [EMAIL PROTECTED]
Acked-by: Serge E. Hallyn [EMAIL PROTECTED]
(Or whatever tag they decide over on lkml that I should be using :)
thanks,
-serge
PS - I won't be acking other patches bc I just haven't looked at
netlink enough - so don't read anything more into that :)
---
fs/inode.c | 29 +
include/linux/fs.h |1 +
2 files changed, 30 insertions(+)
Index: 2.6.20-cr/fs/inode.c
===
--- 2.6.20-cr.orig/fs/inode.c
+++ 2.6.20-cr/fs/inode.c
@@ -877,6 +877,35 @@
EXPORT_SYMBOL(ilookup);
+
+/**
+ * ilookup_unhased - search for an inode in the superblock
+ * @sb: super block of file system to search
+ * @ino: inode number to search for
+ *
+ * The ilookup_unhashed browse the superblock inode list to find the inode.
+ *
+ * If the inode is found in the inode list stored in the superblock, the
inode is
+ * with an incremented reference count.
+ *
+ * Otherwise NULL is returned.
+ */
+struct inode *ilookup_unhashed(struct super_block *sb, unsigned long ino)
+{
+ struct inode *inode = NULL;
+
+ spin_lock(inode_lock);
+ list_for_each_entry(inode, sb-s_inodes, i_sb_list)
+ if (inode-i_ino == ino) {
+ __iget(inode);
+ break;
+ }
+ spin_unlock(inode_lock);
+ return inode;
+
+}
+EXPORT_SYMBOL(ilookup_unhashed);
+
/**
* iget5_locked - obtain an inode from a mounted file system
* @sb: super block of file system
Index: 2.6.20-cr/include/linux/fs.h
===
--- 2.6.20-cr.orig/include/linux/fs.h
+++ 2.6.20-cr/include/linux/fs.h
@@ -1657,6 +1657,7 @@
extern struct inode *ilookup5(struct super_block *sb, unsigned long hashval,
int (*test)(struct inode *, void *), void *data);
extern struct inode *ilookup(struct super_block *sb, unsigned long ino);
+extern struct inode *ilookup_unhashed(struct super_block *sb, unsigned long
ino);
extern struct inode * iget5_locked(struct super_block *, unsigned long, int
(*test)(struct inode *, void *), int (*set)(struct inode *, void *), void *);
extern struct inode * iget_locked(struct super_block *, unsigned long);
--
___
Containers mailing list
[EMAIL PROTECTED]
https://lists.linux-foundation.org/mailman/listinfo/containers
___
Containers mailing list
[EMAIL PROTECTED]
https://lists.linux-foundation.org/mailman/listinfo/containers
___
Devel mailing list
Devel@openvz.org
https://openvz.org/mailman/listinfo/devel
[Devel] Re: [patch 1/5][RFC - ipv4/udp checkpoint/restart] : add lookup for unhashed inode
Serge E. Hallyn wrote:
Quoting [EMAIL PROTECTED] ([EMAIL PROTECTED]):
The socket relies on the sockfs. In some cases, the socket are orphans and
it is not possible to access them via a file descriptor, this is the case for
example for timewait sockets. Hopefully, an inode is still usable to specify
a socket. This one can be retrieved from /proc/net/tcp for orphan sockets or
from a fstat.
When a socket is created the socket inode is added to the sockfs.
Unfortunatly, this one is not stored into the hashed inode list, so
I need a helper to browse the inode list contained in the superblock
of the sockfs.
This is one solution, another solution is to stored the inode into
the hashed list when socket is created.
I assume that would be unacceptable overhead on a very busy server.
Walking all the inodes NUM_INODES(task_set) for a checkpoint could
be a real bottleneck, but at least it's only at checkpoint time.
Have you checked net-dev archives for discussions about not hashing
these inodes? I suppose at some point you'll want to ask there what the
preference is.
I didn't looked at the netdev archive, but, sure, I will dig and ask to
netdev@
Thanks.
But certainly for now this seems the right approach.
Signed-off-by: Daniel Lezcano [EMAIL PROTECTED]
Acked-by: Serge E. Hallyn [EMAIL PROTECTED]
(Or whatever tag they decide over on lkml that I should be using :)
thanks,
-serge
PS - I won't be acking other patches bc I just haven't looked at
netlink enough - so don't read anything more into that :)
---
fs/inode.c | 29 +
include/linux/fs.h |1 +
2 files changed, 30 insertions(+)
Index: 2.6.20-cr/fs/inode.c
===
--- 2.6.20-cr.orig/fs/inode.c
+++ 2.6.20-cr/fs/inode.c
@@ -877,6 +877,35 @@
EXPORT_SYMBOL(ilookup);
+
+/**
+ * ilookup_unhased - search for an inode in the superblock
+ * @sb:super block of file system to search
+ * @ino: inode number to search for
+ *
+ * The ilookup_unhashed browse the superblock inode list to find the inode.
+ *
+ * If the inode is found in the inode list stored in the superblock, the inode
is
+ * with an incremented reference count.
+ *
+ * Otherwise NULL is returned.
+ */
+struct inode *ilookup_unhashed(struct super_block *sb, unsigned long ino)
+{
+ struct inode *inode = NULL;
+
+ spin_lock(inode_lock);
+ list_for_each_entry(inode, sb-s_inodes, i_sb_list)
+ if (inode-i_ino == ino) {
+ __iget(inode);
+ break;
+ }
+ spin_unlock(inode_lock);
+ return inode;
+
+}
+EXPORT_SYMBOL(ilookup_unhashed);
+
/**
* iget5_locked - obtain an inode from a mounted file system
* @sb:super block of file system
Index: 2.6.20-cr/include/linux/fs.h
===
--- 2.6.20-cr.orig/include/linux/fs.h
+++ 2.6.20-cr/include/linux/fs.h
@@ -1657,6 +1657,7 @@
extern struct inode *ilookup5(struct super_block *sb, unsigned long hashval,
int (*test)(struct inode *, void *), void *data);
extern struct inode *ilookup(struct super_block *sb, unsigned long ino);
+extern struct inode *ilookup_unhashed(struct super_block *sb, unsigned long
ino);
extern struct inode * iget5_locked(struct super_block *, unsigned long, int
(*test)(struct inode *, void *), int (*set)(struct inode *, void *), void *);
extern struct inode * iget_locked(struct super_block *, unsigned long);
--
___
Containers mailing list
[EMAIL PROTECTED]
https://lists.linux-foundation.org/mailman/listinfo/containers
___
Containers mailing list
[EMAIL PROTECTED]
https://lists.linux-foundation.org/mailman/listinfo/containers
___
Devel mailing list
Devel@openvz.org
https://openvz.org/mailman/listinfo/devel
