Subject: [NFS] Forcefully resetting a lock

Hi all,

Sometimes a file lock gets stuck. Is there any way on either server or
client to obtain a list of locks? Or a list of processes/clients
locking a particular file?
And the million dollar question: is it possible to forcefully remove a
lock?

I'm using NFSv4 on Linux 2.6.18 (server and client).

Met vriendelijke groet,


Erik Hensema
--
HostingXS
eXcellent Service

Telefoon: 024 - 324 91 77
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2008-04-22 23:15:34

by J. Bruce Fields

[permalink] [raw]
Subject: Re: [NFS] Forcefully resetting a lock

On Fri, Apr 18, 2008 at 02:19:18PM -0400, bfields wrote:
> Really it should be now, though there's another week or so when we can
> submit stuff if it's in good shape.
>
> But I'm feeling bad about letting this go recently, so I'll look at the
> last couple issues and do some testing over the next few days...

OK, I changed the return value to -EIO in the case locks weren't
unlocked. (Better suggestions welcomed. I notice lockd actually BUG()s
in a similar situation elsewhere in the code, but that's probably not
right.)

I also simplified the nlm_traverse_files() change so now it's just:

@@ -241,6 +248,8 @@ nlm_traverse_files(void *data, nlm_host_match_fn_t match)
mutex_lock(&nlm_file_mutex);
for (i = 0; i < FILE_NRHASH; i++) {
hlist_for_each_entry_safe(file, pos, next, &nlm_files[i], f_list) {
+ if (is_failover_file && !is_failover_file(data, file))
+ continue;
file->f_count++;
mutex_unlock(&nlm_file_mutex);

Since the "continue" happens before we do anything at all with that
file, I believe this is safe, and avoids the need for the extra
nlm_file_inuse() call.

And I split the patch into two (unlock_ip, unlock_fs) and edited the
commit messages a little.

The only testing I've done was just connecthon tests plus a simple
manual test with unlock_filesystem (acquiring a lock from a client,
echoing path to unlock_filesystem, verifying that it's gone from
/proc/locks).

Revised patches follow....

--b.

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2008-04-22 23:17:47

by J. Bruce Fields

[permalink] [raw]
Subject: [NFS] [PATCH] lockd: unlock lockd locks associated with a given server ip

From: Wendy Cheng <[email protected]>

For high-availability NFS service, we generally need to be able to drop
file locks held on the exported filesystem before moving clients to a
new server. Currently the only way to do that is by shutting down lockd
entirely, which is often undesireable (for example, if you want to
continue exporting other filesystems).

This patch allows the administrator to release all locks held by clients
accessing the client through a given server ip address, by echoing that
address to a new file, /proc/fs/nfsd/unlock_ip, as in:

shell> echo 10.1.1.2 > /proc/fs/nfsd/unlock_ip

The expected sequence of events can be:
1. Tear down the IP address
2. Unexport the path
3. Write IP to /proc/fs/nfsd/unlock_ip to unlock files
4. Signal peer to begin take-over.

For now we only support IPv4 addresses and NFSv2/v3 (NFSv4 locks are not
affected).

Also, if unmounting the filesystem is required, we assume at step 3 that
clients using the given server ip are the only clients holding locks on
the given filesystem; otherwise, an additional patch is required to
allow revoking all locks held by lockd on a given filesystem.

Signed-off-by: S. Wendy Cheng <[email protected]>
Cc: Lon Hohberger <[email protected]>
Cc: Christoph Hellwig <[email protected]>
Signed-off-by: J. Bruce Fields <[email protected]>

fs/lockd/svcsubs.c | 66 +++++++++++++++++++++++++++++++++++++++-----
fs/nfsd/nfsctl.c | 65 +++++++++++++++++++++++++++++++++++++++++++
include/linux/lockd/lockd.h | 7 ++++
3 files changed, 131 insertions(+), 7 deletions(-)
---
fs/lockd/svcsubs.c | 36 +++++++++++++++++++++++++++++++-----
fs/nfsd/nfsctl.c | 33 +++++++++++++++++++++++++++++++++
include/linux/lockd/lockd.h | 7 ++++++-
3 files changed, 70 insertions(+), 6 deletions(-)

diff --git a/fs/lockd/svcsubs.c b/fs/lockd/svcsubs.c
index dbbefbc..e12daba 100644
--- a/fs/lockd/svcsubs.c
+++ b/fs/lockd/svcsubs.c
@@ -18,6 +18,8 @@
#include <linux/lockd/lockd.h>
#include <linux/lockd/share.h>
#include <linux/lockd/sm_inter.h>
+#include <linux/module.h>
+#include <linux/mount.h>

#define NLMDBG_FACILITY NLMDBG_SVCSUBS

@@ -230,7 +232,7 @@ nlm_file_inuse(struct nlm_file *file)
* Loop over all files in the file table.
*/
static int
-nlm_traverse_files(struct nlm_host *host, nlm_host_match_fn_t match)
+nlm_traverse_files(void *data, nlm_host_match_fn_t match)
{
struct hlist_node *pos, *next;
struct nlm_file *file;
@@ -244,7 +246,7 @@ nlm_traverse_files(struct nlm_host *host, nlm_host_match_fn_t match)

/* Traverse locks, blocks and shares of this file
* and update file->f_locks count */
- if (nlm_inspect_file(host, file, match))
+ if (nlm_inspect_file(data, file, match))
ret = 1;

mutex_lock(&nlm_file_mutex);
@@ -303,21 +305,27 @@ nlm_release_file(struct nlm_file *file)
* Used by nlmsvc_invalidate_all
*/
static int
-nlmsvc_mark_host(struct nlm_host *host, struct nlm_host *dummy)
+nlmsvc_mark_host(void *data, struct nlm_host *dummy)
{
+ struct nlm_host *host = data;
+
host->h_inuse = 1;
return 0;
}

static int
-nlmsvc_same_host(struct nlm_host *host, struct nlm_host *other)
+nlmsvc_same_host(void *data, struct nlm_host *other)
{
+ struct nlm_host *host = data;
+
return host == other;
}

static int
-nlmsvc_is_client(struct nlm_host *host, struct nlm_host *dummy)
+nlmsvc_is_client(void *data, struct nlm_host *dummy)
{
+ struct nlm_host *host = data;
+
if (host->h_server) {
/* we are destroying locks even though the client
* hasn't asked us too, so don't unmonitor the
@@ -370,3 +378,21 @@ nlmsvc_invalidate_all(void)
*/
nlm_traverse_files(NULL, nlmsvc_is_client);
}
+
+static int
+nlmsvc_failover_file_ok_ip(void *datap, struct nlm_host *host)
+{
+ __be32 *server_addr = datap;
+
+ return host->h_saddr.sin_addr.s_addr == *server_addr;
+}
+
+int
+nlmsvc_failover_ip(__be32 server_addr)
+{
+ int ret;
+ ret = nlm_traverse_files(&server_addr, nlmsvc_failover_file_ok_ip);
+ return ret ? -EIO : 0;
+
+}
+EXPORT_SYMBOL_GPL(nlmsvc_failover_ip);
diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c
index 8516137..02c3949 100644
--- a/fs/nfsd/nfsctl.c
+++ b/fs/nfsd/nfsctl.c
@@ -22,6 +22,7 @@
#include <linux/seq_file.h>
#include <linux/pagemap.h>
#include <linux/init.h>
+#include <linux/inet.h>
#include <linux/string.h>
#include <linux/smp_lock.h>
#include <linux/ctype.h>
@@ -35,6 +36,7 @@
#include <linux/nfsd/cache.h>
#include <linux/nfsd/xdr.h>
#include <linux/nfsd/syscall.h>
+#include <linux/lockd/lockd.h>

#include <asm/uaccess.h>

@@ -52,6 +54,7 @@ enum {
NFSD_Getfs,
NFSD_List,
NFSD_Fh,
+ NFSD_FO_UnlockIP,
NFSD_Threads,
NFSD_Pool_Threads,
NFSD_Versions,
@@ -88,6 +91,8 @@ static ssize_t write_leasetime(struct file *file, char *buf, size_t size);
static ssize_t write_recoverydir(struct file *file, char *buf, size_t size);
#endif

+static ssize_t failover_unlock_ip(struct file *file, char *buf, size_t size);
+
static ssize_t (*write_op[])(struct file *, char *, size_t) = {
[NFSD_Svc] = write_svc,
[NFSD_Add] = write_add,
@@ -97,6 +102,7 @@ static ssize_t (*write_op[])(struct file *, char *, size_t) = {
[NFSD_Getfd] = write_getfd,
[NFSD_Getfs] = write_getfs,
[NFSD_Fh] = write_filehandle,
+ [NFSD_FO_UnlockIP] = failover_unlock_ip,
[NFSD_Threads] = write_threads,
[NFSD_Pool_Threads] = write_pool_threads,
[NFSD_Versions] = write_versions,
@@ -288,6 +294,31 @@ static ssize_t write_getfd(struct file *file, char *buf, size_t size)
return err;
}

+static ssize_t failover_unlock_ip(struct file *file, char *buf, size_t size)
+{
+ __be32 server_ip;
+ char *fo_path, c;
+ int b1, b2, b3, b4;
+
+ /* sanity check */
+ if (size == 0)
+ return -EINVAL;
+
+ if (buf[size-1] != '\n')
+ return -EINVAL;
+
+ fo_path = buf;
+ if (qword_get(&buf, fo_path, size) < 0)
+ return -EINVAL;
+
+ /* get ipv4 address */
+ if (sscanf(fo_path, "%u.%u.%u.%u%c", &b1, &b2, &b3, &b4, &c) != 4)
+ return -EINVAL;
+ server_ip = htonl((((((b1<<8)|b2)<<8)|b3)<<8)|b4);
+
+ return nlmsvc_failover_ip(server_ip);
+}
+
static ssize_t write_filehandle(struct file *file, char *buf, size_t size)
{
/* request is:
@@ -696,6 +727,8 @@ static int nfsd_fill_super(struct super_block * sb, void * data, int silent)
[NFSD_Getfd] = {".getfd", &transaction_ops, S_IWUSR|S_IRUSR},
[NFSD_Getfs] = {".getfs", &transaction_ops, S_IWUSR|S_IRUSR},
[NFSD_List] = {"exports", &exports_operations, S_IRUGO},
+ [NFSD_FO_UnlockIP] = {"unlock_ip",
+ &transaction_ops, S_IWUSR|S_IRUSR},
[NFSD_Fh] = {"filehandle", &transaction_ops, S_IWUSR|S_IRUSR},
[NFSD_Threads] = {"threads", &transaction_ops, S_IWUSR|S_IRUSR},
[NFSD_Pool_Threads] = {"pool_threads", &transaction_ops, S_IWUSR|S_IRUSR},
diff --git a/include/linux/lockd/lockd.h b/include/linux/lockd/lockd.h
index 4babb2a..f06d2db 100644
--- a/include/linux/lockd/lockd.h
+++ b/include/linux/lockd/lockd.h
@@ -191,7 +191,7 @@ void nsm_release(struct nsm_handle *);
* This is used in garbage collection and resource reclaim
* A return value != 0 means destroy the lock/block/share
*/
-typedef int (*nlm_host_match_fn_t)(struct nlm_host *cur, struct nlm_host *ref);
+typedef int (*nlm_host_match_fn_t)(void *cur, struct nlm_host *ref);

/*
* Server-side lock handling
@@ -217,6 +217,11 @@ void nlmsvc_mark_resources(void);
void nlmsvc_free_host_resources(struct nlm_host *);
void nlmsvc_invalidate_all(void);

+/*
+ * Cluster failover support
+ */
+int nlmsvc_failover_ip(__be32 server_addr);
+
static __inline__ struct inode *
nlmsvc_file_inode(struct nlm_file *file)
{
--
1.5.5.rc1


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2008-04-22 23:19:06

by J. Bruce Fields

[permalink] [raw]
Subject: [NFS] [PATCH] lockd: unlock lockd locks held for a certain filesystem

From: Wendy Cheng <[email protected]>

Add /proc/fs/nfsd/unlock_filesystem, which allows e.g.:

shell> echo /mnt/sfs1 > /proc/fs/nfsd/unlock_filesystem

so that a filesystem can be unmounted before allowing a peer nfsd to
take over nfs service for the filesystem.

Signed-off-by: S. Wendy Cheng <[email protected]>
Cc: Lon Hohberger <[email protected]>
Cc: Christoph Hellwig <[email protected]>
Signed-off-by: J. Bruce Fields <[email protected]>

fs/lockd/svcsubs.c | 66 +++++++++++++++++++++++++++++++++++++++-----
fs/nfsd/nfsctl.c | 65 +++++++++++++++++++++++++++++++++++++++++++
include/linux/lockd/lockd.h | 7 ++++
3 files changed, 131 insertions(+), 7 deletions(-)
---
fs/lockd/svcsubs.c | 38 +++++++++++++++++++++++++++++++++-----
fs/nfsd/nfsctl.c | 32 ++++++++++++++++++++++++++++++++
include/linux/lockd/lockd.h | 1 +
3 files changed, 66 insertions(+), 5 deletions(-)

diff --git a/fs/lockd/svcsubs.c b/fs/lockd/svcsubs.c
index e12daba..24589de 100644
--- a/fs/lockd/svcsubs.c
+++ b/fs/lockd/svcsubs.c
@@ -196,6 +196,12 @@ again:
return 0;
}

+static int
+nlmsvc_always_match(void *dummy1, struct nlm_host *dummy2)
+{
+ return 1;
+}
+
/*
* Inspect a single file
*/
@@ -232,7 +238,8 @@ nlm_file_inuse(struct nlm_file *file)
* Loop over all files in the file table.
*/
static int
-nlm_traverse_files(void *data, nlm_host_match_fn_t match)
+nlm_traverse_files(void *data, nlm_host_match_fn_t match,
+ int (*is_failover_file)(void *data, struct nlm_file *file))
{
struct hlist_node *pos, *next;
struct nlm_file *file;
@@ -241,6 +248,8 @@ nlm_traverse_files(void *data, nlm_host_match_fn_t match)
mutex_lock(&nlm_file_mutex);
for (i = 0; i < FILE_NRHASH; i++) {
hlist_for_each_entry_safe(file, pos, next, &nlm_files[i], f_list) {
+ if (is_failover_file && !is_failover_file(data, file))
+ continue;
file->f_count++;
mutex_unlock(&nlm_file_mutex);

@@ -345,7 +354,7 @@ void
nlmsvc_mark_resources(void)
{
dprintk("lockd: nlmsvc_mark_resources\n");
- nlm_traverse_files(NULL, nlmsvc_mark_host);
+ nlm_traverse_files(NULL, nlmsvc_mark_host, NULL);
}

/*
@@ -356,7 +365,7 @@ nlmsvc_free_host_resources(struct nlm_host *host)
{
dprintk("lockd: nlmsvc_free_host_resources\n");

- if (nlm_traverse_files(host, nlmsvc_same_host)) {
+ if (nlm_traverse_files(host, nlmsvc_same_host, NULL)) {
printk(KERN_WARNING
"lockd: couldn't remove all locks held by %s\n",
host->h_name);
@@ -376,8 +385,26 @@ nlmsvc_invalidate_all(void)
* turn, which is about as inefficient as it gets.
* Now we just do it once in nlm_traverse_files.
*/
- nlm_traverse_files(NULL, nlmsvc_is_client);
+ nlm_traverse_files(NULL, nlmsvc_is_client, NULL);
+}
+
+static int
+nlmsvc_failover_file_ok_path(void *datap, struct nlm_file *file)
+{
+ struct nameidata *nd = datap;
+ return nd->path.mnt->mnt_sb == file->f_file->f_path.mnt->mnt_sb;
+}
+
+int
+nlmsvc_failover_path(struct nameidata *nd)
+{
+ int ret;
+
+ ret = nlm_traverse_files(nd, nlmsvc_always_match,
+ nlmsvc_failover_file_ok_path);
+ return ret ? -EIO : 0;
}
+EXPORT_SYMBOL_GPL(nlmsvc_failover_path);

static int
nlmsvc_failover_file_ok_ip(void *datap, struct nlm_host *host)
@@ -391,7 +418,8 @@ int
nlmsvc_failover_ip(__be32 server_addr)
{
int ret;
- ret = nlm_traverse_files(&server_addr, nlmsvc_failover_file_ok_ip);
+ ret = nlm_traverse_files(&server_addr, nlmsvc_failover_file_ok_ip,
+ NULL);
return ret ? -EIO : 0;

}
diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c
index 02c3949..05a59cc 100644
--- a/fs/nfsd/nfsctl.c
+++ b/fs/nfsd/nfsctl.c
@@ -55,6 +55,7 @@ enum {
NFSD_List,
NFSD_Fh,
NFSD_FO_UnlockIP,
+ NFSD_FO_UnlockFS,
NFSD_Threads,
NFSD_Pool_Threads,
NFSD_Versions,
@@ -92,6 +93,7 @@ static ssize_t write_recoverydir(struct file *file, char *buf, size_t size);
#endif

static ssize_t failover_unlock_ip(struct file *file, char *buf, size_t size);
+static ssize_t failover_unlock_fs(struct file *file, char *buf, size_t size);

static ssize_t (*write_op[])(struct file *, char *, size_t) = {
[NFSD_Svc] = write_svc,
@@ -103,6 +105,7 @@ static ssize_t (*write_op[])(struct file *, char *, size_t) = {
[NFSD_Getfs] = write_getfs,
[NFSD_Fh] = write_filehandle,
[NFSD_FO_UnlockIP] = failover_unlock_ip,
+ [NFSD_FO_UnlockFS] = failover_unlock_fs,
[NFSD_Threads] = write_threads,
[NFSD_Pool_Threads] = write_pool_threads,
[NFSD_Versions] = write_versions,
@@ -319,6 +322,33 @@ static ssize_t failover_unlock_ip(struct file *file, char *buf, size_t size)
return nlmsvc_failover_ip(server_ip);
}

+static ssize_t failover_unlock_fs(struct file *file, char *buf, size_t size)
+{
+ struct nameidata nd;
+ char *fo_path;
+ int error;
+
+ /* sanity check */
+ if (size == 0)
+ return -EINVAL;
+
+ if (buf[size-1] != '\n')
+ return -EINVAL;
+
+ fo_path = buf;
+ if (qword_get(&buf, fo_path, size) < 0)
+ return -EINVAL;
+
+ error = path_lookup(fo_path, 0, &nd);
+ if (error)
+ return error;
+
+ error = nlmsvc_failover_path(&nd);
+
+ path_put(&nd.path);
+ return error;
+}
+
static ssize_t write_filehandle(struct file *file, char *buf, size_t size)
{
/* request is:
@@ -729,6 +759,8 @@ static int nfsd_fill_super(struct super_block * sb, void * data, int silent)
[NFSD_List] = {"exports", &exports_operations, S_IRUGO},
[NFSD_FO_UnlockIP] = {"unlock_ip",
&transaction_ops, S_IWUSR|S_IRUSR},
+ [NFSD_FO_UnlockFS] = {"unlock_filesystem",
+ &transaction_ops, S_IWUSR|S_IRUSR},
[NFSD_Fh] = {"filehandle", &transaction_ops, S_IWUSR|S_IRUSR},
[NFSD_Threads] = {"threads", &transaction_ops, S_IWUSR|S_IRUSR},
[NFSD_Pool_Threads] = {"pool_threads", &transaction_ops, S_IWUSR|S_IRUSR},
diff --git a/include/linux/lockd/lockd.h b/include/linux/lockd/lockd.h
index f06d2db..cde8605 100644
--- a/include/linux/lockd/lockd.h
+++ b/include/linux/lockd/lockd.h
@@ -220,6 +220,7 @@ void nlmsvc_invalidate_all(void);
/*
* Cluster failover support
*/
+int nlmsvc_failover_path(struct nameidata *nd);
int nlmsvc_failover_ip(__be32 server_addr);

static __inline__ struct inode *
--
1.5.5.rc1


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2008-04-23 02:57:59

by Wendy Cheng

[permalink] [raw]
Subject: Re: [NFS] [PATCH] lockd: unlock lockd locks held for a certain filesystem

ok, just pulled the linux kernel source few minutes ago. will restart
cluster testings and let you know tomorrow... Wendy


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2008-04-23 07:44:56

by Christoph Hellwig

[permalink] [raw]
Subject: Re: [NFS] [PATCH] lockd: unlock lockd locks held for a certain filesystem

Please don't pass down the nameidata, but just the super_block. That's
all we need in the lower layer functions.


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2008-04-23 18:13:54

by J. Bruce Fields

[permalink] [raw]
Subject: Re: [NFS] [PATCH] lockd: unlock lockd locks held for a certain filesystem

On Wed, Apr 23, 2008 at 09:44:22AM +0200, Christoph Hellwig wrote:
> Please don't pass down the nameidata, but just the super_block. That's
> all we need in the lower layer functions.

Yep, I agree that's nicer; here's the result.

--b.

commit 26a816586b71877d8a84fbb436373099384e328b
Author: Wendy Cheng <[email protected]>
Date: Thu Jan 17 11:10:12 2008 -0500

lockd: unlock lockd locks held for a certain filesystem

Add /proc/fs/nfsd/unlock_filesystem, which allows e.g.:

shell> echo /mnt/sfs1 > /proc/fs/nfsd/unlock_filesystem

so that a filesystem can be unmounted before allowing a peer nfsd to
take over nfs service for the filesystem.

Signed-off-by: S. Wendy Cheng <[email protected]>
Cc: Lon Hohberger <[email protected]>
Cc: Christoph Hellwig <[email protected]>
Signed-off-by: J. Bruce Fields <[email protected]>

fs/lockd/svcsubs.c | 66 +++++++++++++++++++++++++++++++++++++++-----
fs/nfsd/nfsctl.c | 65 +++++++++++++++++++++++++++++++++++++++++++
include/linux/lockd/lockd.h | 7 ++++
3 files changed, 131 insertions(+), 7 deletions(-)

diff --git a/fs/lockd/svcsubs.c b/fs/lockd/svcsubs.c
index e12daba..dcdcff6 100644
--- a/fs/lockd/svcsubs.c
+++ b/fs/lockd/svcsubs.c
@@ -196,6 +196,12 @@ again:
return 0;
}

+static int
+nlmsvc_always_match(void *dummy1, struct nlm_host *dummy2)
+{
+ return 1;
+}
+
/*
* Inspect a single file
*/
@@ -232,7 +238,8 @@ nlm_file_inuse(struct nlm_file *file)
* Loop over all files in the file table.
*/
static int
-nlm_traverse_files(void *data, nlm_host_match_fn_t match)
+nlm_traverse_files(void *data, nlm_host_match_fn_t match,
+ int (*is_failover_file)(void *data, struct nlm_file *file))
{
struct hlist_node *pos, *next;
struct nlm_file *file;
@@ -241,6 +248,8 @@ nlm_traverse_files(void *data, nlm_host_match_fn_t match)
mutex_lock(&nlm_file_mutex);
for (i = 0; i < FILE_NRHASH; i++) {
hlist_for_each_entry_safe(file, pos, next, &nlm_files[i], f_list) {
+ if (is_failover_file && !is_failover_file(data, file))
+ continue;
file->f_count++;
mutex_unlock(&nlm_file_mutex);

@@ -345,7 +354,7 @@ void
nlmsvc_mark_resources(void)
{
dprintk("lockd: nlmsvc_mark_resources\n");
- nlm_traverse_files(NULL, nlmsvc_mark_host);
+ nlm_traverse_files(NULL, nlmsvc_mark_host, NULL);
}

/*
@@ -356,7 +365,7 @@ nlmsvc_free_host_resources(struct nlm_host *host)
{
dprintk("lockd: nlmsvc_free_host_resources\n");

- if (nlm_traverse_files(host, nlmsvc_same_host)) {
+ if (nlm_traverse_files(host, nlmsvc_same_host, NULL)) {
printk(KERN_WARNING
"lockd: couldn't remove all locks held by %s\n",
host->h_name);
@@ -376,8 +385,27 @@ nlmsvc_invalidate_all(void)
* turn, which is about as inefficient as it gets.
* Now we just do it once in nlm_traverse_files.
*/
- nlm_traverse_files(NULL, nlmsvc_is_client);
+ nlm_traverse_files(NULL, nlmsvc_is_client, NULL);
+}
+
+static int
+nlmsvc_failover_file_ok_path(void *datap, struct nlm_file *file)
+{
+ struct super_block *sb = datap;
+
+ return sb == file->f_file->f_path.mnt->mnt_sb;
+}
+
+int
+nlmsvc_failover_path(struct super_block *sb)
+{
+ int ret;
+
+ ret = nlm_traverse_files(sb, nlmsvc_always_match,
+ nlmsvc_failover_file_ok_path);
+ return ret ? -EIO : 0;
}
+EXPORT_SYMBOL_GPL(nlmsvc_failover_path);

static int
nlmsvc_failover_file_ok_ip(void *datap, struct nlm_host *host)
@@ -391,7 +419,8 @@ int
nlmsvc_failover_ip(__be32 server_addr)
{
int ret;
- ret = nlm_traverse_files(&server_addr, nlmsvc_failover_file_ok_ip);
+ ret = nlm_traverse_files(&server_addr, nlmsvc_failover_file_ok_ip,
+ NULL);
return ret ? -EIO : 0;

}
diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c
index 02c3949..b4ca5c9 100644
--- a/fs/nfsd/nfsctl.c
+++ b/fs/nfsd/nfsctl.c
@@ -55,6 +55,7 @@ enum {
NFSD_List,
NFSD_Fh,
NFSD_FO_UnlockIP,
+ NFSD_FO_UnlockFS,
NFSD_Threads,
NFSD_Pool_Threads,
NFSD_Versions,
@@ -92,6 +93,7 @@ static ssize_t write_recoverydir(struct file *file, char *buf, size_t size);
#endif

static ssize_t failover_unlock_ip(struct file *file, char *buf, size_t size);
+static ssize_t failover_unlock_fs(struct file *file, char *buf, size_t size);

static ssize_t (*write_op[])(struct file *, char *, size_t) = {
[NFSD_Svc] = write_svc,
@@ -103,6 +105,7 @@ static ssize_t (*write_op[])(struct file *, char *, size_t) = {
[NFSD_Getfs] = write_getfs,
[NFSD_Fh] = write_filehandle,
[NFSD_FO_UnlockIP] = failover_unlock_ip,
+ [NFSD_FO_UnlockFS] = failover_unlock_fs,
[NFSD_Threads] = write_threads,
[NFSD_Pool_Threads] = write_pool_threads,
[NFSD_Versions] = write_versions,
@@ -319,6 +322,33 @@ static ssize_t failover_unlock_ip(struct file *file, char *buf, size_t size)
return nlmsvc_failover_ip(server_ip);
}

+static ssize_t failover_unlock_fs(struct file *file, char *buf, size_t size)
+{
+ struct nameidata nd;
+ char *fo_path;
+ int error;
+
+ /* sanity check */
+ if (size == 0)
+ return -EINVAL;
+
+ if (buf[size-1] != '\n')
+ return -EINVAL;
+
+ fo_path = buf;
+ if (qword_get(&buf, fo_path, size) < 0)
+ return -EINVAL;
+
+ error = path_lookup(fo_path, 0, &nd);
+ if (error)
+ return error;
+
+ error = nlmsvc_failover_path(nd.path.mnt->mnt_sb);
+
+ path_put(&nd.path);
+ return error;
+}
+
static ssize_t write_filehandle(struct file *file, char *buf, size_t size)
{
/* request is:
@@ -729,6 +759,8 @@ static int nfsd_fill_super(struct super_block * sb, void * data, int silent)
[NFSD_List] = {"exports", &exports_operations, S_IRUGO},
[NFSD_FO_UnlockIP] = {"unlock_ip",
&transaction_ops, S_IWUSR|S_IRUSR},
+ [NFSD_FO_UnlockFS] = {"unlock_filesystem",
+ &transaction_ops, S_IWUSR|S_IRUSR},
[NFSD_Fh] = {"filehandle", &transaction_ops, S_IWUSR|S_IRUSR},
[NFSD_Threads] = {"threads", &transaction_ops, S_IWUSR|S_IRUSR},
[NFSD_Pool_Threads] = {"pool_threads", &transaction_ops, S_IWUSR|S_IRUSR},
diff --git a/include/linux/lockd/lockd.h b/include/linux/lockd/lockd.h
index f06d2db..7cd9c8e 100644
--- a/include/linux/lockd/lockd.h
+++ b/include/linux/lockd/lockd.h
@@ -220,6 +220,7 @@ void nlmsvc_invalidate_all(void);
/*
* Cluster failover support
*/
+int nlmsvc_failover_path(struct super_block *sb);
int nlmsvc_failover_ip(__be32 server_addr);

static __inline__ struct inode *

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2008-04-23 18:28:20

by Christoph Hellwig

[permalink] [raw]
Subject: Re: [NFS] [PATCH] lockd: unlock lockd locks held for a certain filesystem

On Wed, Apr 23, 2008 at 01:12:40PM -0400, J. Bruce Fields wrote:
> +int nlmsvc_failover_path(struct super_block *sb);

With a super_block argument the path suffix doesn't make sense anymore.
Should probably be an _sb instead.


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2008-04-23 20:01:35

by J. Bruce Fields

[permalink] [raw]
Subject: Re: [NFS] [PATCH] lockd: unlock lockd locks held for a certain filesystem

On Wed, Apr 23, 2008 at 07:52:26PM +0200, Christoph Hellwig wrote:
> On Wed, Apr 23, 2008 at 01:12:40PM -0400, J. Bruce Fields wrote:
> > +int nlmsvc_failover_path(struct super_block *sb);
>
> With a super_block argument the path suffix doesn't make sense anymore.
> Should probably be an _sb instead.

OK. As long as we're renaming stuff, I always found
nlmsvc_failover_{ip,path}() a little vague, so I've made them
nlmsvc_unlock_all_by_{ip,sb}().

--b.

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2008-04-23 20:37:28

by Wendy Cheng

[permalink] [raw]
Subject: Re: [PATCH] lockd: unlock lockd locks held for a certain filesystem

#if defined(BRUCE_CHECK_THIS_OUT)
error = nlmsvc_failover_path(nd.path.mnt->mnt_sb);
#else
error = nlmsvc_failover_path(nd.mnt->mnt_sb);
#endif

-- Wendy

---------- based on the following email ----------------------------

J. Bruce Fields wrote:
> On Wed, Apr 23, 2008 at 09:44:22AM +0200, Christoph Hellwig wrote:
>
>> Please don't pass down the nameidata, but just the super_block. That's
>> all we need in the lower layer functions.
>>
>
> Yep, I agree that's nicer; here's the result.
>
> --b.
>
> commit 26a816586b71877d8a84fbb436373099384e328b
> Author: Wendy Cheng <[email protected]>
> Date: Thu Jan 17 11:10:12 2008 -0500
>
> lockd: unlock lockd locks held for a certain filesystem
>
> Add /proc/fs/nfsd/unlock_filesystem, which allows e.g.:
>
> shell> echo /mnt/sfs1 > /proc/fs/nfsd/unlock_filesystem
>
> so that a filesystem can be unmounted before allowing a peer nfsd to
> take over nfs service for the filesystem.
>
> Signed-off-by: S. Wendy Cheng <[email protected]>
> Cc: Lon Hohberger <[email protected]>
> Cc: Christoph Hellwig <[email protected]>
> Signed-off-by: J. Bruce Fields <[email protected]>
>
> fs/lockd/svcsubs.c | 66 +++++++++++++++++++++++++++++++++++++++-----
> fs/nfsd/nfsctl.c | 65 +++++++++++++++++++++++++++++++++++++++++++
> include/linux/lockd/lockd.h | 7 ++++
> 3 files changed, 131 insertions(+), 7 deletions(-)
>
> diff --git a/fs/lockd/svcsubs.c b/fs/lockd/svcsubs.c
> index e12daba..dcdcff6 100644
> --- a/fs/lockd/svcsubs.c
> +++ b/fs/lockd/svcsubs.c
> @@ -196,6 +196,12 @@ again:
> return 0;
> }
>
> +static int
> +nlmsvc_always_match(void *dummy1, struct nlm_host *dummy2)
> +{
> + return 1;
> +}
> +
> /*
> * Inspect a single file
> */
> @@ -232,7 +238,8 @@ nlm_file_inuse(struct nlm_file *file)
> * Loop over all files in the file table.
> */
> static int
> -nlm_traverse_files(void *data, nlm_host_match_fn_t match)
> +nlm_traverse_files(void *data, nlm_host_match_fn_t match,
> + int (*is_failover_file)(void *data, struct nlm_file *file))
> {
> struct hlist_node *pos, *next;
> struct nlm_file *file;
> @@ -241,6 +248,8 @@ nlm_traverse_files(void *data, nlm_host_match_fn_t match)
> mutex_lock(&nlm_file_mutex);
> for (i = 0; i < FILE_NRHASH; i++) {
> hlist_for_each_entry_safe(file, pos, next, &nlm_files[i], f_list) {
> + if (is_failover_file && !is_failover_file(data, file))
> + continue;
> file->f_count++;
> mutex_unlock(&nlm_file_mutex);
>
> @@ -345,7 +354,7 @@ void
> nlmsvc_mark_resources(void)
> {
> dprintk("lockd: nlmsvc_mark_resources\n");
> - nlm_traverse_files(NULL, nlmsvc_mark_host);
> + nlm_traverse_files(NULL, nlmsvc_mark_host, NULL);
> }
>
> /*
> @@ -356,7 +365,7 @@ nlmsvc_free_host_resources(struct nlm_host *host)
> {
> dprintk("lockd: nlmsvc_free_host_resources\n");
>
> - if (nlm_traverse_files(host, nlmsvc_same_host)) {
> + if (nlm_traverse_files(host, nlmsvc_same_host, NULL)) {
> printk(KERN_WARNING
> "lockd: couldn't remove all locks held by %s\n",
> host->h_name);
> @@ -376,8 +385,27 @@ nlmsvc_invalidate_all(void)
> * turn, which is about as inefficient as it gets.
> * Now we just do it once in nlm_traverse_files.
> */
> - nlm_traverse_files(NULL, nlmsvc_is_client);
> + nlm_traverse_files(NULL, nlmsvc_is_client, NULL);
> +}
> +
> +static int
> +nlmsvc_failover_file_ok_path(void *datap, struct nlm_file *file)
> +{
> + struct super_block *sb = datap;
> +
> + return sb == file->f_file->f_path.mnt->mnt_sb;
> +}
> +
> +int
> +nlmsvc_failover_path(struct super_block *sb)
> +{
> + int ret;
> +
> + ret = nlm_traverse_files(sb, nlmsvc_always_match,
> + nlmsvc_failover_file_ok_path);
> + return ret ? -EIO : 0;
> }
> +EXPORT_SYMBOL_GPL(nlmsvc_failover_path);
>
> static int
> nlmsvc_failover_file_ok_ip(void *datap, struct nlm_host *host)
> @@ -391,7 +419,8 @@ int
> nlmsvc_failover_ip(__be32 server_addr)
> {
> int ret;
> - ret = nlm_traverse_files(&server_addr, nlmsvc_failover_file_ok_ip);
> + ret = nlm_traverse_files(&server_addr, nlmsvc_failover_file_ok_ip,
> + NULL);
> return ret ? -EIO : 0;
>
> }
> diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c
> index 02c3949..b4ca5c9 100644
> --- a/fs/nfsd/nfsctl.c
> +++ b/fs/nfsd/nfsctl.c
> @@ -55,6 +55,7 @@ enum {
> NFSD_List,
> NFSD_Fh,
> NFSD_FO_UnlockIP,
> + NFSD_FO_UnlockFS,
> NFSD_Threads,
> NFSD_Pool_Threads,
> NFSD_Versions,
> @@ -92,6 +93,7 @@ static ssize_t write_recoverydir(struct file *file, char *buf, size_t size);
> #endif
>
> static ssize_t failover_unlock_ip(struct file *file, char *buf, size_t size);
> +static ssize_t failover_unlock_fs(struct file *file, char *buf, size_t size);
>
> static ssize_t (*write_op[])(struct file *, char *, size_t) = {
> [NFSD_Svc] = write_svc,
> @@ -103,6 +105,7 @@ static ssize_t (*write_op[])(struct file *, char *, size_t) = {
> [NFSD_Getfs] = write_getfs,
> [NFSD_Fh] = write_filehandle,
> [NFSD_FO_UnlockIP] = failover_unlock_ip,
> + [NFSD_FO_UnlockFS] = failover_unlock_fs,
> [NFSD_Threads] = write_threads,
> [NFSD_Pool_Threads] = write_pool_threads,
> [NFSD_Versions] = write_versions,
> @@ -319,6 +322,33 @@ static ssize_t failover_unlock_ip(struct file *file, char *buf, size_t size)
> return nlmsvc_failover_ip(server_ip);
> }
>
> +static ssize_t failover_unlock_fs(struct file *file, char *buf, size_t size)
> +{
> + struct nameidata nd;
> + char *fo_path;
> + int error;
> +
> + /* sanity check */
> + if (size == 0)
> + return -EINVAL;
> +
> + if (buf[size-1] != '\n')
> + return -EINVAL;
> +
> + fo_path = buf;
> + if (qword_get(&buf, fo_path, size) < 0)
> + return -EINVAL;
> +
> + error = path_lookup(fo_path, 0, &nd);
> + if (error)
> + return error;
> +
> + error = nlmsvc_failover_path(nd.path.mnt->mnt_sb);
> +
> + path_put(&nd.path);
> + return error;
> +}
> +
> static ssize_t write_filehandle(struct file *file, char *buf, size_t size)
> {
> /* request is:
> @@ -729,6 +759,8 @@ static int nfsd_fill_super(struct super_block * sb, void * data, int silent)
> [NFSD_List] = {"exports", &exports_operations, S_IRUGO},
> [NFSD_FO_UnlockIP] = {"unlock_ip",
> &transaction_ops, S_IWUSR|S_IRUSR},
> + [NFSD_FO_UnlockFS] = {"unlock_filesystem",
> + &transaction_ops, S_IWUSR|S_IRUSR},
> [NFSD_Fh] = {"filehandle", &transaction_ops, S_IWUSR|S_IRUSR},
> [NFSD_Threads] = {"threads", &transaction_ops, S_IWUSR|S_IRUSR},
> [NFSD_Pool_Threads] = {"pool_threads", &transaction_ops, S_IWUSR|S_IRUSR},
> diff --git a/include/linux/lockd/lockd.h b/include/linux/lockd/lockd.h
> index f06d2db..7cd9c8e 100644
> --- a/include/linux/lockd/lockd.h
> +++ b/include/linux/lockd/lockd.h
> @@ -220,6 +220,7 @@ void nlmsvc_invalidate_all(void);
> /*
> * Cluster failover support
> */
> +int nlmsvc_failover_path(struct super_block *sb);
> int nlmsvc_failover_ip(__be32 server_addr);
>
> static __inline__ struct inode *
>


2008-04-23 21:02:33

by J. Bruce Fields

[permalink] [raw]
Subject: Re: [PATCH] lockd: unlock lockd locks held for a certain filesystem

On Wed, Apr 23, 2008 at 04:39:11PM -0400, Wendy Cheng wrote:
> #if defined(BRUCE_CHECK_THIS_OUT)
> error = nlmsvc_failover_path(nd.path.mnt->mnt_sb);
> #else
> error = nlmsvc_failover_path(nd.mnt->mnt_sb);
> #endif

The vfsmount and dentry got moved into the path argument sometime in the
last kernel version or so. Is there a macro defining the latter as a
shortcut for the former? I didn't see one.

--b.

>
> -- Wendy
>
> ---------- based on the following email ----------------------------
>
> J. Bruce Fields wrote:
>> On Wed, Apr 23, 2008 at 09:44:22AM +0200, Christoph Hellwig wrote:
>>
>>> Please don't pass down the nameidata, but just the super_block. That's
>>> all we need in the lower layer functions.
>>>
>>
>> Yep, I agree that's nicer; here's the result.
>>
>> --b.
>>
>> commit 26a816586b71877d8a84fbb436373099384e328b
>> Author: Wendy Cheng <[email protected]>
>> Date: Thu Jan 17 11:10:12 2008 -0500
>>
>> lockd: unlock lockd locks held for a certain filesystem
>> Add /proc/fs/nfsd/unlock_filesystem, which allows e.g.:
>> shell> echo /mnt/sfs1 > /proc/fs/nfsd/unlock_filesystem
>> so that a filesystem can be unmounted before allowing a peer
>> nfsd to
>> take over nfs service for the filesystem.
>> Signed-off-by: S. Wendy Cheng <[email protected]>
>> Cc: Lon Hohberger <[email protected]>
>> Cc: Christoph Hellwig <[email protected]>
>> Signed-off-by: J. Bruce Fields <[email protected]>
>> fs/lockd/svcsubs.c | 66
>> +++++++++++++++++++++++++++++++++++++++-----
>> fs/nfsd/nfsctl.c | 65 +++++++++++++++++++++++++++++++++++++++++++
>> include/linux/lockd/lockd.h | 7 ++++
>> 3 files changed, 131 insertions(+), 7 deletions(-)
>>
>> diff --git a/fs/lockd/svcsubs.c b/fs/lockd/svcsubs.c
>> index e12daba..dcdcff6 100644
>> --- a/fs/lockd/svcsubs.c
>> +++ b/fs/lockd/svcsubs.c
>> @@ -196,6 +196,12 @@ again:
>> return 0;
>> }
>> +static int
>> +nlmsvc_always_match(void *dummy1, struct nlm_host *dummy2)
>> +{
>> + return 1;
>> +}
>> +
>> /*
>> * Inspect a single file
>> */
>> @@ -232,7 +238,8 @@ nlm_file_inuse(struct nlm_file *file)
>> * Loop over all files in the file table.
>> */
>> static int
>> -nlm_traverse_files(void *data, nlm_host_match_fn_t match)
>> +nlm_traverse_files(void *data, nlm_host_match_fn_t match,
>> + int (*is_failover_file)(void *data, struct nlm_file *file))
>> {
>> struct hlist_node *pos, *next;
>> struct nlm_file *file;
>> @@ -241,6 +248,8 @@ nlm_traverse_files(void *data, nlm_host_match_fn_t match)
>> mutex_lock(&nlm_file_mutex);
>> for (i = 0; i < FILE_NRHASH; i++) {
>> hlist_for_each_entry_safe(file, pos, next, &nlm_files[i], f_list) {
>> + if (is_failover_file && !is_failover_file(data, file))
>> + continue;
>> file->f_count++;
>> mutex_unlock(&nlm_file_mutex);
>> @@ -345,7 +354,7 @@ void
>> nlmsvc_mark_resources(void)
>> {
>> dprintk("lockd: nlmsvc_mark_resources\n");
>> - nlm_traverse_files(NULL, nlmsvc_mark_host);
>> + nlm_traverse_files(NULL, nlmsvc_mark_host, NULL);
>> }
>> /*
>> @@ -356,7 +365,7 @@ nlmsvc_free_host_resources(struct nlm_host *host)
>> {
>> dprintk("lockd: nlmsvc_free_host_resources\n");
>> - if (nlm_traverse_files(host, nlmsvc_same_host)) {
>> + if (nlm_traverse_files(host, nlmsvc_same_host, NULL)) {
>> printk(KERN_WARNING
>> "lockd: couldn't remove all locks held by %s\n",
>> host->h_name);
>> @@ -376,8 +385,27 @@ nlmsvc_invalidate_all(void)
>> * turn, which is about as inefficient as it gets.
>> * Now we just do it once in nlm_traverse_files.
>> */
>> - nlm_traverse_files(NULL, nlmsvc_is_client);
>> + nlm_traverse_files(NULL, nlmsvc_is_client, NULL);
>> +}
>> +
>> +static int
>> +nlmsvc_failover_file_ok_path(void *datap, struct nlm_file *file)
>> +{
>> + struct super_block *sb = datap;
>> +
>> + return sb == file->f_file->f_path.mnt->mnt_sb;
>> +}
>> +
>> +int
>> +nlmsvc_failover_path(struct super_block *sb)
>> +{
>> + int ret;
>> +
>> + ret = nlm_traverse_files(sb, nlmsvc_always_match,
>> + nlmsvc_failover_file_ok_path);
>> + return ret ? -EIO : 0;
>> }
>> +EXPORT_SYMBOL_GPL(nlmsvc_failover_path);
>> static int
>> nlmsvc_failover_file_ok_ip(void *datap, struct nlm_host *host)
>> @@ -391,7 +419,8 @@ int
>> nlmsvc_failover_ip(__be32 server_addr)
>> {
>> int ret;
>> - ret = nlm_traverse_files(&server_addr, nlmsvc_failover_file_ok_ip);
>> + ret = nlm_traverse_files(&server_addr, nlmsvc_failover_file_ok_ip,
>> + NULL);
>> return ret ? -EIO : 0;
>> }
>> diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c
>> index 02c3949..b4ca5c9 100644
>> --- a/fs/nfsd/nfsctl.c
>> +++ b/fs/nfsd/nfsctl.c
>> @@ -55,6 +55,7 @@ enum {
>> NFSD_List,
>> NFSD_Fh,
>> NFSD_FO_UnlockIP,
>> + NFSD_FO_UnlockFS,
>> NFSD_Threads,
>> NFSD_Pool_Threads,
>> NFSD_Versions,
>> @@ -92,6 +93,7 @@ static ssize_t write_recoverydir(struct file *file, char *buf, size_t size);
>> #endif
>> static ssize_t failover_unlock_ip(struct file *file, char *buf,
>> size_t size);
>> +static ssize_t failover_unlock_fs(struct file *file, char *buf, size_t size);
>> static ssize_t (*write_op[])(struct file *, char *, size_t) = {
>> [NFSD_Svc] = write_svc,
>> @@ -103,6 +105,7 @@ static ssize_t (*write_op[])(struct file *, char *, size_t) = {
>> [NFSD_Getfs] = write_getfs,
>> [NFSD_Fh] = write_filehandle,
>> [NFSD_FO_UnlockIP] = failover_unlock_ip,
>> + [NFSD_FO_UnlockFS] = failover_unlock_fs,
>> [NFSD_Threads] = write_threads,
>> [NFSD_Pool_Threads] = write_pool_threads,
>> [NFSD_Versions] = write_versions,
>> @@ -319,6 +322,33 @@ static ssize_t failover_unlock_ip(struct file *file, char *buf, size_t size)
>> return nlmsvc_failover_ip(server_ip);
>> }
>> +static ssize_t failover_unlock_fs(struct file *file, char *buf,
>> size_t size)
>> +{
>> + struct nameidata nd;
>> + char *fo_path;
>> + int error;
>> +
>> + /* sanity check */
>> + if (size == 0)
>> + return -EINVAL;
>> +
>> + if (buf[size-1] != '\n')
>> + return -EINVAL;
>> +
>> + fo_path = buf;
>> + if (qword_get(&buf, fo_path, size) < 0)
>> + return -EINVAL;
>> +
>> + error = path_lookup(fo_path, 0, &nd);
>> + if (error)
>> + return error;
>> +
>> + error = nlmsvc_failover_path(nd.path.mnt->mnt_sb);
>> +
>> + path_put(&nd.path);
>> + return error;
>> +}
>> +
>> static ssize_t write_filehandle(struct file *file, char *buf, size_t size)
>> {
>> /* request is:
>> @@ -729,6 +759,8 @@ static int nfsd_fill_super(struct super_block * sb, void * data, int silent)
>> [NFSD_List] = {"exports", &exports_operations, S_IRUGO},
>> [NFSD_FO_UnlockIP] = {"unlock_ip",
>> &transaction_ops, S_IWUSR|S_IRUSR},
>> + [NFSD_FO_UnlockFS] = {"unlock_filesystem",
>> + &transaction_ops, S_IWUSR|S_IRUSR},
>> [NFSD_Fh] = {"filehandle", &transaction_ops, S_IWUSR|S_IRUSR},
>> [NFSD_Threads] = {"threads", &transaction_ops, S_IWUSR|S_IRUSR},
>> [NFSD_Pool_Threads] = {"pool_threads", &transaction_ops, S_IWUSR|S_IRUSR},
>> diff --git a/include/linux/lockd/lockd.h b/include/linux/lockd/lockd.h
>> index f06d2db..7cd9c8e 100644
>> --- a/include/linux/lockd/lockd.h
>> +++ b/include/linux/lockd/lockd.h
>> @@ -220,6 +220,7 @@ void nlmsvc_invalidate_all(void);
>> /*
>> * Cluster failover support
>> */
>> +int nlmsvc_failover_path(struct super_block *sb);
>> int nlmsvc_failover_ip(__be32 server_addr);
>> static __inline__ struct inode *
>>
>

2008-04-23 21:15:37

by Wendy Cheng

[permalink] [raw]
Subject: Re: [PATCH] lockd: unlock lockd locks held for a certain filesystem

J. Bruce Fields wrote:
> On Wed, Apr 23, 2008 at 04:39:11PM -0400, Wendy Cheng wrote:
>
>> #if defined(BRUCE_CHECK_THIS_OUT)
>> error = nlmsvc_failover_path(nd.path.mnt->mnt_sb);
>> #else
>> error = nlmsvc_failover_path(nd.mnt->mnt_sb);
>> #endif
>>
>
> The vfsmount and dentry got moved into the path argument sometime in the
> last kernel version or so. Is there a macro defining the latter as a
> shortcut for the former? I didn't see one.
>
>
>
Sorry, just realized my kernel is too old (2.6.25) .. It would be
cumbersome for me to test RHCS with newer kernels. Linux is really a
moving target :( ....

Anyway, will think of something else to test this out..

-- Wendy


2008-04-23 21:39:23

by J. Bruce Fields

[permalink] [raw]
Subject: Re: [PATCH] lockd: unlock lockd locks held for a certain filesystem

On Wed, Apr 23, 2008 at 05:17:29PM -0400, Wendy Cheng wrote:
> J. Bruce Fields wrote:
>> On Wed, Apr 23, 2008 at 04:39:11PM -0400, Wendy Cheng wrote:
>>
>>> #if defined(BRUCE_CHECK_THIS_OUT)
>>> error = nlmsvc_failover_path(nd.path.mnt->mnt_sb);
>>> #else
>>> error = nlmsvc_failover_path(nd.mnt->mnt_sb);
>>> #endif
>>>
>>
>> The vfsmount and dentry got moved into the path argument sometime in the
>> last kernel version or so. Is there a macro defining the latter as a
>> shortcut for the former? I didn't see one.
>>
>>
>>
> Sorry, just realized my kernel is too old (2.6.25)

2.6.25 is'nt that old quite yet! OK, I get the idea, anyway.

> .. It would be
> cumbersome for me to test RHCS with newer kernels. Linux is really a
> moving target :( ....
>
> Anyway, will think of something else to test this out..

OK, thanks. I did some very basic tests, and I'm not terribly worried
about it; at worst, it's unlikely to break anything that's already
working. But let me know what you find out.

I've sent off my merge request for 2.6.26, but I may try to bundle this
up with a few smaller patches I think I've missed and submit another
request before the weekend.

--b.

2008-04-23 21:42:53

by Wendy Cheng

[permalink] [raw]
Subject: Re: [PATCH] lockd: unlock lockd locks held for a certain filesystem

J. Bruce Fields wrote:
> On Wed, Apr 23, 2008 at 05:17:29PM -0400, Wendy Cheng wrote:
>
>> J. Bruce Fields wrote:
>>
>>> On Wed, Apr 23, 2008 at 04:39:11PM -0400, Wendy Cheng wrote:
>>>
>>>
>>>> #if defined(BRUCE_CHECK_THIS_OUT)
>>>> error = nlmsvc_failover_path(nd.path.mnt->mnt_sb);
>>>> #else
>>>> error = nlmsvc_failover_path(nd.mnt->mnt_sb);
>>>> #endif
>>>>
>>>>
>>> The vfsmount and dentry got moved into the path argument sometime in the
>>> last kernel version or so. Is there a macro defining the latter as a
>>> shortcut for the former? I didn't see one.
>>>
>>>
>>>
>>>
>> Sorry, just realized my kernel is too old (2.6.25)
>>
>
> 2.6.25 is'nt that old quite yet! OK, I get the idea, anyway.
>
>
>> .. It would be
>> cumbersome for me to test RHCS with newer kernels. Linux is really a
>> moving target :( ....
>>
>> Anyway, will think of something else to test this out..
>>
>
> OK, thanks. I did some very basic tests, and I'm not terribly worried
> about it; at worst, it's unlikely to break anything that's already
> working. But let me know what you find out.
>
> I've sent off my merge request for 2.6.26, but I may try to bundle this
> up with a few smaller patches I think I've missed and submit another
> request before the weekend.
>

Please do .. this has been going on for more than two years .. it would
be ridiculous to put it off any longer. I'll see what I can do here to
help out.

-- Wendy


2008-04-17 21:55:27

by J. Bruce Fields

[permalink] [raw]
Subject: Re: [NFS] Forcefully resetting a lock

On Wed, Apr 16, 2008 at 02:39:19PM -0500, Wendy Cheng wrote:
> J. Bruce Fields wrote:
>> On Wed, Apr 16, 2008 at 10:15:19AM -0500, Wendy Cheng wrote:
>>
>>> Erik Hensema / HostingXS Internet Services wrote:
>>>
>>>> Hi all,
>>>>
>>>> Sometimes a file lock gets stuck. Is there any way on either server
>>>> or client to obtain a list of locks? Or a list of
>>>> processes/clients locking a particular file?
>>>> And the million dollar question: is it possible to forcefully
>>>> remove a lock?
>>>>
>>>> I'm using NFSv4 on Linux 2.6.18 (server and client).
>>>>
>>>>
>>> *Cough* !
>>>
>>> Bruce, so what happens to my lock dropping patch that was said "will
>>> get pulled into 2.6.26 kernel" ?
>>>
>>
>> Gulp.
>>
>> I started an alternative implementation, and got it to the point where
>> it was basically working (but I didn't completely trust it). And I did
>> a small fix or two on your patches, but I seem to recall there were one
>> or more todo's there too.
>>
>> Then I dropped both for a couple weeks.
>>
>
> Be carefully. .. "a couple weeks" can turn into "a couple years" .. It
> has been more than 2 years since my first patch submission. Regardless
> the patch has been repeatedly requested and had gone thru thorough
> testings, it just sits there idling while Linux nfs server keeps
> suffering the very same issue.

Yes, apologies for not getting this done on time.

> Don't get too ambitious. Cluster issues are not trivial - please take
> one step at a time. The patch is very usable *and* solves an immediate
> issue *and* has a clean boundary with existing main-line logic. I really
> don't see the reason to delay it.

My current version of your patch follows.

I've rebased it a couple times (the only change I recall being required
was a trivial fix to take into account reorganization of struct
nameidata.). I also made two other changes; any objections to either?:

- I believe the addition of f_iaddr to store the server-side ip
address was not quite correct, since the struct nlm_file may
be shared by multiple clients accessing the filesystem through
multiple server ip's--possibly not an issue for your use case,
but easily fixable, since there's already a host->h_saddr
filled in for server-side nlm_host structs, which saves us the
trouble of inventing a new field.

- I made the unlock-by-path match filesystems on superblock, not
vfs_mount: my understanding is that its purpose is to release
all of the locks held by nfs which would prevent completely
unmounting the given filesystem. So we should be matching on
all locks for a given superblock, not just those for a single
vfsmount of that superblock.

Still to fix:

- The write methods appear to return the number of failed unlock
requests. But positive return values have a special meaning
to nfsctl_transaction_write(). This looks like a bug.

- The nlm_traverse_files() changes are hairy.

Also still to do, though not necessarily blocks to submitting them:

- Figure out how to drop locks held by nfsv4 clients as well.

- Fix the ip address type.

--b.

commit 5f4e32d8544564c477c04009393db914145d6d5b
Author: Wendy Cheng <[email protected]>
Date: Thu Jan 17 11:10:12 2008 -0500

NLM failover unlock commands

Two new NFSD procfs files are added:
/proc/fs/nfsd/unlock_ip
/proc/fs/nfsd/unlock_filesystem

They are intended to allow admin or user mode script to release NLM locks
based on either a path name or a server in-bound ip address (ipv4 for now)
as:

shell> echo 10.1.1.2 > /proc/fs/nfsd/unlock_ip
shell> echo /mnt/sfs1 > /proc/fs/nfsd/unlock_filesystem

The expected sequence of events can be:
1. Tear down the IP address
2. Unexport the path
3. Write IP to /proc/fs/nfsd/unlock_ip to unlock files
4. If unmount required, write path name to
/proc/fs/nfsd/unlock_filesystem, then unmount.
5. Signal peer to begin take-over.

Signed-off-by: S. Wendy Cheng <[email protected]>
Signed-off-by: Lon Hohberger <[email protected]>
Signed-off-by: Christoph Hellwig <[email protected]>

fs/lockd/svcsubs.c | 66 +++++++++++++++++++++++++++++++++++++++-----
fs/nfsd/nfsctl.c | 65 +++++++++++++++++++++++++++++++++++++++++++
include/linux/lockd/lockd.h | 7 ++++
3 files changed, 131 insertions(+), 7 deletions(-)

diff --git a/fs/lockd/svcsubs.c b/fs/lockd/svcsubs.c
index dbbefbc..a82019e 100644
--- a/fs/lockd/svcsubs.c
+++ b/fs/lockd/svcsubs.c
@@ -18,6 +18,8 @@
#include <linux/lockd/lockd.h>
#include <linux/lockd/share.h>
#include <linux/lockd/sm_inter.h>
+#include <linux/module.h>
+#include <linux/mount.h>

#define NLMDBG_FACILITY NLMDBG_SVCSUBS

@@ -194,6 +196,12 @@ again:
return 0;
}

+static int
+nlmsvc_always_match(void *dummy1, struct nlm_host *dummy2)
+{
+ return 1;
+}
+
/*
* Inspect a single file
*/
@@ -230,7 +238,8 @@ nlm_file_inuse(struct nlm_file *file)
* Loop over all files in the file table.
*/
static int
-nlm_traverse_files(struct nlm_host *host, nlm_host_match_fn_t match)
+nlm_traverse_files(void *data, nlm_host_match_fn_t match,
+ int (*is_failover_file)(void *data, struct nlm_file *file))
{
struct hlist_node *pos, *next;
struct nlm_file *file;
@@ -244,8 +253,17 @@ nlm_traverse_files(struct nlm_host *host, nlm_host_match_fn_t match)

/* Traverse locks, blocks and shares of this file
* and update file->f_locks count */
- if (nlm_inspect_file(host, file, match))
- ret = 1;
+
+ if (likely(is_failover_file == NULL) ||
+ is_failover_file(data, file)) {
+ /*
+ * Note that nlm_inspect_file updates f_locks
+ * and ret is the number of files that can't
+ * be unlocked.
+ */
+ ret += nlm_inspect_file(data, file, match);
+ } else
+ file->f_locks = nlm_file_inuse(file);

mutex_lock(&nlm_file_mutex);
file->f_count--;
@@ -303,21 +321,27 @@ nlm_release_file(struct nlm_file *file)
* Used by nlmsvc_invalidate_all
*/
static int
-nlmsvc_mark_host(struct nlm_host *host, struct nlm_host *dummy)
+nlmsvc_mark_host(void *data, struct nlm_host *dummy)
{
+ struct nlm_host *host = data;
+
host->h_inuse = 1;
return 0;
}

static int
-nlmsvc_same_host(struct nlm_host *host, struct nlm_host *other)
+nlmsvc_same_host(void *data, struct nlm_host *other)
{
+ struct nlm_host *host = data;
+
return host == other;
}

static int
-nlmsvc_is_client(struct nlm_host *host, struct nlm_host *dummy)
+nlmsvc_is_client(void *data, struct nlm_host *dummy)
{
+ struct nlm_host *host = data;
+
if (host->h_server) {
/* we are destroying locks even though the client
* hasn't asked us too, so don't unmonitor the
@@ -337,7 +361,7 @@ void
nlmsvc_mark_resources(void)
{
dprintk("lockd: nlmsvc_mark_resources\n");
- nlm_traverse_files(NULL, nlmsvc_mark_host);
+ nlm_traverse_files(NULL, nlmsvc_mark_host, NULL);
}

/*
@@ -348,7 +372,7 @@ nlmsvc_free_host_resources(struct nlm_host *host)
{
dprintk("lockd: nlmsvc_free_host_resources\n");

- if (nlm_traverse_files(host, nlmsvc_same_host)) {
+ if (nlm_traverse_files(host, nlmsvc_same_host, NULL)) {
printk(KERN_WARNING
"lockd: couldn't remove all locks held by %s\n",
host->h_name);
@@ -368,5 +392,36 @@ nlmsvc_invalidate_all(void)
* turn, which is about as inefficient as it gets.
* Now we just do it once in nlm_traverse_files.
*/
- nlm_traverse_files(NULL, nlmsvc_is_client);
+ nlm_traverse_files(NULL, nlmsvc_is_client, NULL);
+}
+
+static int
+nlmsvc_failover_file_ok_path(void *datap, struct nlm_file *file)
+{
+ struct nameidata *nd = datap;
+ return nd->path.mnt->mnt_sb == file->f_file->f_path.mnt->mnt_sb;
+}
+
+int
+nlmsvc_failover_path(struct nameidata *nd)
+{
+ return nlm_traverse_files(nd, nlmsvc_always_match,
+ nlmsvc_failover_file_ok_path);
+}
+EXPORT_SYMBOL_GPL(nlmsvc_failover_path);
+
+static int
+nlmsvc_failover_file_ok_ip(void *datap, struct nlm_host *host)
+{
+ __be32 *server_addr = datap;
+
+ return host->h_saddr.sin_addr.s_addr == *server_addr;
+}
+
+int
+nlmsvc_failover_ip(__be32 server_addr)
+{
+ return nlm_traverse_files(&server_addr, nlmsvc_failover_file_ok_ip,
+ NULL);
}
+EXPORT_SYMBOL_GPL(nlmsvc_failover_ip);
diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c
index 8516137..05a59cc 100644
--- a/fs/nfsd/nfsctl.c
+++ b/fs/nfsd/nfsctl.c
@@ -22,6 +22,7 @@
#include <linux/seq_file.h>
#include <linux/pagemap.h>
#include <linux/init.h>
+#include <linux/inet.h>
#include <linux/string.h>
#include <linux/smp_lock.h>
#include <linux/ctype.h>
@@ -35,6 +36,7 @@
#include <linux/nfsd/cache.h>
#include <linux/nfsd/xdr.h>
#include <linux/nfsd/syscall.h>
+#include <linux/lockd/lockd.h>

#include <asm/uaccess.h>

@@ -52,6 +54,8 @@ enum {
NFSD_Getfs,
NFSD_List,
NFSD_Fh,
+ NFSD_FO_UnlockIP,
+ NFSD_FO_UnlockFS,
NFSD_Threads,
NFSD_Pool_Threads,
NFSD_Versions,
@@ -88,6 +92,9 @@ static ssize_t write_leasetime(struct file *file, char *buf, size_t size);
static ssize_t write_recoverydir(struct file *file, char *buf, size_t size);
#endif

+static ssize_t failover_unlock_ip(struct file *file, char *buf, size_t size);
+static ssize_t failover_unlock_fs(struct file *file, char *buf, size_t size);
+
static ssize_t (*write_op[])(struct file *, char *, size_t) = {
[NFSD_Svc] = write_svc,
[NFSD_Add] = write_add,
@@ -97,6 +104,8 @@ static ssize_t (*write_op[])(struct file *, char *, size_t) = {
[NFSD_Getfd] = write_getfd,
[NFSD_Getfs] = write_getfs,
[NFSD_Fh] = write_filehandle,
+ [NFSD_FO_UnlockIP] = failover_unlock_ip,
+ [NFSD_FO_UnlockFS] = failover_unlock_fs,
[NFSD_Threads] = write_threads,
[NFSD_Pool_Threads] = write_pool_threads,
[NFSD_Versions] = write_versions,
@@ -288,6 +297,58 @@ static ssize_t write_getfd(struct file *file, char *buf, size_t size)
return err;
}

+static ssize_t failover_unlock_ip(struct file *file, char *buf, size_t size)
+{
+ __be32 server_ip;
+ char *fo_path, c;
+ int b1, b2, b3, b4;
+
+ /* sanity check */
+ if (size == 0)
+ return -EINVAL;
+
+ if (buf[size-1] != '\n')
+ return -EINVAL;
+
+ fo_path = buf;
+ if (qword_get(&buf, fo_path, size) < 0)
+ return -EINVAL;
+
+ /* get ipv4 address */
+ if (sscanf(fo_path, "%u.%u.%u.%u%c", &b1, &b2, &b3, &b4, &c) != 4)
+ return -EINVAL;
+ server_ip = htonl((((((b1<<8)|b2)<<8)|b3)<<8)|b4);
+
+ return nlmsvc_failover_ip(server_ip);
+}
+
+static ssize_t failover_unlock_fs(struct file *file, char *buf, size_t size)
+{
+ struct nameidata nd;
+ char *fo_path;
+ int error;
+
+ /* sanity check */
+ if (size == 0)
+ return -EINVAL;
+
+ if (buf[size-1] != '\n')
+ return -EINVAL;
+
+ fo_path = buf;
+ if (qword_get(&buf, fo_path, size) < 0)
+ return -EINVAL;
+
+ error = path_lookup(fo_path, 0, &nd);
+ if (error)
+ return error;
+
+ error = nlmsvc_failover_path(&nd);
+
+ path_put(&nd.path);
+ return error;
+}
+
static ssize_t write_filehandle(struct file *file, char *buf, size_t size)
{
/* request is:
@@ -696,6 +757,10 @@ static int nfsd_fill_super(struct super_block * sb, void * data, int silent)
[NFSD_Getfd] = {".getfd", &transaction_ops, S_IWUSR|S_IRUSR},
[NFSD_Getfs] = {".getfs", &transaction_ops, S_IWUSR|S_IRUSR},
[NFSD_List] = {"exports", &exports_operations, S_IRUGO},
+ [NFSD_FO_UnlockIP] = {"unlock_ip",
+ &transaction_ops, S_IWUSR|S_IRUSR},
+ [NFSD_FO_UnlockFS] = {"unlock_filesystem",
+ &transaction_ops, S_IWUSR|S_IRUSR},
[NFSD_Fh] = {"filehandle", &transaction_ops, S_IWUSR|S_IRUSR},
[NFSD_Threads] = {"threads", &transaction_ops, S_IWUSR|S_IRUSR},
[NFSD_Pool_Threads] = {"pool_threads", &transaction_ops, S_IWUSR|S_IRUSR},
diff --git a/include/linux/lockd/lockd.h b/include/linux/lockd/lockd.h
index 4babb2a..cde8605 100644
--- a/include/linux/lockd/lockd.h
+++ b/include/linux/lockd/lockd.h
@@ -191,7 +191,7 @@ void nsm_release(struct nsm_handle *);
* This is used in garbage collection and resource reclaim
* A return value != 0 means destroy the lock/block/share
*/
-typedef int (*nlm_host_match_fn_t)(struct nlm_host *cur, struct nlm_host *ref);
+typedef int (*nlm_host_match_fn_t)(void *cur, struct nlm_host *ref);

/*
* Server-side lock handling
@@ -217,6 +217,12 @@ void nlmsvc_mark_resources(void);
void nlmsvc_free_host_resources(struct nlm_host *);
void nlmsvc_invalidate_all(void);

+/*
+ * Cluster failover support
+ */
+int nlmsvc_failover_path(struct nameidata *nd);
+int nlmsvc_failover_ip(__be32 server_addr);
+
static __inline__ struct inode *
nlmsvc_file_inode(struct nlm_file *file)
{

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2008-04-18 18:20:04

by J. Bruce Fields

[permalink] [raw]
Subject: Re: [NFS] Forcefully resetting a lock

On Fri, Apr 18, 2008 at 09:02:06AM -0500, Wendy Cheng wrote:
> J. Bruce Fields wrote:
>> My current version of your patch follows.
>>
>> I've rebased it a couple times (the only change I recall being required
>> was a trivial fix to take into account reorganization of struct
>> nameidata.). I also made two other changes; any objections to either?:
>>
>
> Thanks for doing this... The changes look good - though I don't have
> chances to test it out yet. When is 2.6.26 code cut-off date (or we have
> missed it again) ?

Really it should be now, though there's another week or so when we can
submit stuff if it's in good shape.

But I'm feeling bad about letting this go recently, so I'll look at the
last couple issues and do some testing over the next few days...

--b.

-------------------------------------------------------------------------
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2008-04-18 14:03:04

by Wendy Cheng

[permalink] [raw]
Subject: Re: [NFS] Forcefully resetting a lock

J. Bruce Fields wrote:
> On Wed, Apr 16, 2008 at 02:39:19PM -0500, Wendy Cheng wrote:
>
>> J. Bruce Fields wrote:
>>
>>> On Wed, Apr 16, 2008 at 10:15:19AM -0500, Wendy Cheng wrote:
>>>
>>>
>>>> Erik Hensema / HostingXS Internet Services wrote:
>>>>
>>>>
>>>>> Hi all,
>>>>>
>>>>> Sometimes a file lock gets stuck. Is there any way on either server
>>>>> or client to obtain a list of locks? Or a list of
>>>>> processes/clients locking a particular file?
>>>>> And the million dollar question: is it possible to forcefully
>>>>> remove a lock?
>>>>>
>>>>> I'm using NFSv4 on Linux 2.6.18 (server and client).
>>>>>
>>>>>
>>>>>
>>>> *Cough* !
>>>>
>>>> Bruce, so what happens to my lock dropping patch that was said "will
>>>> get pulled into 2.6.26 kernel" ?
>>>>
>>>>
>>> Gulp.
>>>
>>> I started an alternative implementation, and got it to the point where
>>> it was basically working (but I didn't completely trust it). And I did
>>> a small fix or two on your patches, but I seem to recall there were one
>>> or more todo's there too.
>>>
>>> Then I dropped both for a couple weeks.
>>>
>>>
>> Be carefully. .. "a couple weeks" can turn into "a couple years" .. It
>> has been more than 2 years since my first patch submission. Regardless
>> the patch has been repeatedly requested and had gone thru thorough
>> testings, it just sits there idling while Linux nfs server keeps
>> suffering the very same issue.
>>
>
> Yes, apologies for not getting this done on time.
>
>
>> Don't get too ambitious. Cluster issues are not trivial - please take
>> one step at a time. The patch is very usable *and* solves an immediate
>> issue *and* has a clean boundary with existing main-line logic. I really
>> don't see the reason to delay it.
>>
>
> My current version of your patch follows.
>
> I've rebased it a couple times (the only change I recall being required
> was a trivial fix to take into account reorganization of struct
> nameidata.). I also made two other changes; any objections to either?:
>

Thanks for doing this... The changes look good - though I don't have
chances to test it out yet. When is 2.6.26 code cut-off date (or we have
missed it again) ?

-- Wendy
>



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2008-04-16 11:44:42

by Jeff Layton

[permalink] [raw]
Subject: Re: [NFS] Forcefully resetting a lock

On Wed, 16 Apr 2008 11:17:24 +0200
Erik Hensema / HostingXS Internet Services <hensema-yolSOB3tinz/[email protected]> wrote:

> Hi all,
>
> Sometimes a file lock gets stuck. Is there any way on either server or
> client to obtain a list of locks? Or a list of processes/clients
> locking a particular file?

$ cat /proc/locks

The PID field can be a little misleading there though. On the server,
it'll generally show the pid of knfsd, and on the client you'll see
the pid of the processes actually doing the locking. As far as I know,
info about which clients have blocked locks isn't exposed.


> And the million dollar question: is it possible to forcefully remove a
> lock?
>

Hmm...with NFSv2/3, yes. You can send a SIGKILL to lockd to make it drop
all of its locks. You'll need to couple that with a statd SM_NOTIFY
event to make everyone recover their locks too...

> I'm using NFSv4 on Linux 2.6.18 (server and client).
>

I don't think the same sort of trick works for NFSv4. I suppose you
could probably shut down all the nfsd's on the server and bring
them back up again. I've never tested that though...

> Met vriendelijke groet,
>
>
> Erik Hensema
> --
> HostingXS
> eXcellent Service
>
> Telefoon: 024 - 324 91 77
> E-mail: hensema-yolSOB3tinz/[email protected]
> Website: http://www.hostingxs.nl/
>
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2008-04-16 15:19:28

by Wendy Cheng

[permalink] [raw]
Subject: Re: [NFS] Forcefully resetting a lock

Erik Hensema / HostingXS Internet Services wrote:
> Hi all,
>
> Sometimes a file lock gets stuck. Is there any way on either server or
> client to obtain a list of locks? Or a list of processes/clients
> locking a particular file?
> And the million dollar question: is it possible to forcefully remove a
> lock?
>
> I'm using NFSv4 on Linux 2.6.18 (server and client).
>
>

*Cough* !

Bruce, so what happens to my lock dropping patch that was said "will get
pulled into 2.6.26 kernel" ?

-- Wendy


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2008-04-16 18:42:50

by J. Bruce Fields

[permalink] [raw]
Subject: Re: [NFS] Forcefully resetting a lock

On Wed, Apr 16, 2008 at 10:15:19AM -0500, Wendy Cheng wrote:
> Erik Hensema / HostingXS Internet Services wrote:
>> Hi all,
>>
>> Sometimes a file lock gets stuck. Is there any way on either server or
>> client to obtain a list of locks? Or a list of processes/clients
>> locking a particular file?
>> And the million dollar question: is it possible to forcefully remove a
>> lock?
>>
>> I'm using NFSv4 on Linux 2.6.18 (server and client).
>>
>>
>
> *Cough* !
>
> Bruce, so what happens to my lock dropping patch that was said "will get
> pulled into 2.6.26 kernel" ?

Gulp.

I started an alternative implementation, and got it to the point where
it was basically working (but I didn't completely trust it). And I did
a small fix or two on your patches, but I seem to recall there were one
or more todo's there too.

Then I dropped both for a couple weeks.

I'll take a harder look this afternoon....

--b.

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2008-04-16 19:39:37

by Wendy Cheng

[permalink] [raw]
Subject: Re: [NFS] Forcefully resetting a lock

J. Bruce Fields wrote:
> On Wed, Apr 16, 2008 at 10:15:19AM -0500, Wendy Cheng wrote:
>
>> Erik Hensema / HostingXS Internet Services wrote:
>>
>>> Hi all,
>>>
>>> Sometimes a file lock gets stuck. Is there any way on either server or
>>> client to obtain a list of locks? Or a list of processes/clients
>>> locking a particular file?
>>> And the million dollar question: is it possible to forcefully remove a
>>> lock?
>>>
>>> I'm using NFSv4 on Linux 2.6.18 (server and client).
>>>
>>>
>>>
>> *Cough* !
>>
>> Bruce, so what happens to my lock dropping patch that was said "will get
>> pulled into 2.6.26 kernel" ?
>>
>
> Gulp.
>
> I started an alternative implementation, and got it to the point where
> it was basically working (but I didn't completely trust it). And I did
> a small fix or two on your patches, but I seem to recall there were one
> or more todo's there too.
>
> Then I dropped both for a couple weeks.
>

Be carefully. .. "a couple weeks" can turn into "a couple years" .. It
has been more than 2 years since my first patch submission. Regardless
the patch has been repeatedly requested and had gone thru thorough
testings, it just sits there idling while Linux nfs server keeps
suffering the very same issue.

Don't get too ambitious. Cluster issues are not trivial - please take
one step at a time. The patch is very usable *and* solves an immediate
issue *and* has a clean boundary with existing main-line logic. I really
don't see the reason to delay it.

-- Wendy


> I'll take a harder look this afternoon....
>
> --b.
>



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