NFS: Always use the same SETCLIENTID boot verifier
Currently our NFS client assigns a unique SETCLIENTID boot verifier
for each server IP address it knows about. It's set to CURRENT_TIME
when the struct nfs_client for that server IP is created.
During the SETCLIENTID operation, our client also presents an
nfs_client_id4 string to servers, as an identifier on which the server
can hang all of this client's NFSv4 state. Our client's
nfs_client_id4 string is unique for each server IP address.
An NFSv4 server is obligated to wipe all NFSv4 state associated with
an nfs_client_id4 string when the client presents the same
nfs_client_id4 string along with a changed SETCLIENTID boot verifier.
When our client unmounts the last of a server's shares, it destroys
that server's struct nfs_client. The next time the client mounts that
NFS server, it creates a fresh struct nfs_client with a fresh boot
verifier. On seeing the fresh verifer, the server wipes any previous
NFSv4 state associated with that nfs_client_id4.
However, NFSv4.1 clients are supposed to present the same
nfs_client_id4 string to all servers. And, to support Transparent
State Migration, the same nfs_client_id4 string should be presented
to all NFSv4.0 servers so they recognize that migrated state for this
client belongs with state a server may already have for this client.
(This is known as the Uniform Client String model).
If the nfs_client_id4 string is the same but the boot verifier changes
for each server IP address, SETCLIENTID and EXCHANGE_ID operations
from such a client could unintentionally result in a server wiping a
client's previously obtained lease.
Thus, if our NFS client is going to use a fixed nfs_client_id4 string,
either for NFSv4.0 or NFSv4.1 mounts, our NFS client should use a
boot verifier that does not change depending on server IP address.
Replace our current per-nfs_client boot verifier with a per-nfs_net
boot verifier.
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2012-05-22 04:45:41 +02:00
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/*
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* NFS-private data for each "struct net". Accessed with net_generic().
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*/
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2011-11-25 15:13:04 +01:00
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#ifndef __NFS_NETNS_H__
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#define __NFS_NETNS_H__
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2012-10-02 12:18:54 +02:00
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#include <linux/nfs4.h>
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2011-11-25 15:13:04 +01:00
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#include <net/net_namespace.h>
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#include <net/netns/generic.h>
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2012-03-11 15:20:23 +01:00
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struct bl_dev_msg {
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int32_t status;
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uint32_t major, minor;
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};
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2011-11-25 15:13:04 +01:00
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struct nfs_net {
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struct cache_detail *nfs_dns_resolve;
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2012-01-10 14:04:24 +01:00
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struct rpc_pipe *bl_device_pipe;
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2012-03-11 15:20:23 +01:00
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struct bl_dev_msg bl_mount_reply;
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2012-03-11 15:20:31 +01:00
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wait_queue_head_t bl_wq;
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2014-09-26 16:02:50 +02:00
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struct mutex bl_mutex;
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2012-01-23 18:26:05 +01:00
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struct list_head nfs_client_list;
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2012-01-23 18:26:14 +01:00
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struct list_head nfs_volume_list;
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2012-07-30 22:05:25 +02:00
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#if IS_ENABLED(CONFIG_NFS_V4)
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2012-01-23 18:26:22 +01:00
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struct idr cb_ident_idr; /* Protected by nfs_client_lock */
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2012-08-20 16:00:36 +02:00
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unsigned short nfs_callback_tcpport;
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2012-08-20 16:00:41 +02:00
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unsigned short nfs_callback_tcpport6;
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2012-08-20 16:00:46 +02:00
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int cb_users[NFS4_MAX_MINOR_VERSION + 1];
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2012-01-23 18:26:22 +01:00
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#endif
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2012-01-23 18:26:31 +01:00
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spinlock_t nfs_client_lock;
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2016-10-02 01:46:26 +02:00
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ktime_t boot_time;
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2014-07-31 13:35:20 +02:00
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#ifdef CONFIG_PROC_FS
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struct proc_dir_entry *proc_nfsfs;
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#endif
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2011-11-25 15:13:04 +01:00
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};
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netns: make struct pernet_operations::id unsigned int
Make struct pernet_operations::id unsigned.
There are 2 reasons to do so:
1)
This field is really an index into an zero based array and
thus is unsigned entity. Using negative value is out-of-bound
access by definition.
2)
On x86_64 unsigned 32-bit data which are mixed with pointers
via array indexing or offsets added or subtracted to pointers
are preffered to signed 32-bit data.
"int" being used as an array index needs to be sign-extended
to 64-bit before being used.
void f(long *p, int i)
{
g(p[i]);
}
roughly translates to
movsx rsi, esi
mov rdi, [rsi+...]
call g
MOVSX is 3 byte instruction which isn't necessary if the variable is
unsigned because x86_64 is zero extending by default.
Now, there is net_generic() function which, you guessed it right, uses
"int" as an array index:
static inline void *net_generic(const struct net *net, int id)
{
...
ptr = ng->ptr[id - 1];
...
}
And this function is used a lot, so those sign extensions add up.
Patch snipes ~1730 bytes on allyesconfig kernel (without all junk
messing with code generation):
add/remove: 0/0 grow/shrink: 70/598 up/down: 396/-2126 (-1730)
Unfortunately some functions actually grow bigger.
This is a semmingly random artefact of code generation with register
allocator being used differently. gcc decides that some variable
needs to live in new r8+ registers and every access now requires REX
prefix. Or it is shifted into r12, so [r12+0] addressing mode has to be
used which is longer than [r8]
However, overall balance is in negative direction:
add/remove: 0/0 grow/shrink: 70/598 up/down: 396/-2126 (-1730)
function old new delta
nfsd4_lock 3886 3959 +73
tipc_link_build_proto_msg 1096 1140 +44
mac80211_hwsim_new_radio 2776 2808 +32
tipc_mon_rcv 1032 1058 +26
svcauth_gss_legacy_init 1413 1429 +16
tipc_bcbase_select_primary 379 392 +13
nfsd4_exchange_id 1247 1260 +13
nfsd4_setclientid_confirm 782 793 +11
...
put_client_renew_locked 494 480 -14
ip_set_sockfn_get 730 716 -14
geneve_sock_add 829 813 -16
nfsd4_sequence_done 721 703 -18
nlmclnt_lookup_host 708 686 -22
nfsd4_lockt 1085 1063 -22
nfs_get_client 1077 1050 -27
tcf_bpf_init 1106 1076 -30
nfsd4_encode_fattr 5997 5930 -67
Total: Before=154856051, After=154854321, chg -0.00%
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-11-17 02:58:21 +01:00
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extern unsigned int nfs_net_id;
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2011-11-25 15:13:04 +01:00
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#endif
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