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afs: Allow dumping of server cursor on operation failure

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Provide an option to allow the file or volume location server cursor to be
dumped if the rotation routine falls off the end without managing to
contact a server.

Signed-off-by: David Howells <dhowells@redhat.com>
This commit is contained in:
David Howells 2018-10-20 00:57:58 +01:00
parent 30062bd13e
commit 744bcd713a
5 changed files with 127 additions and 0 deletions
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12
fs/afs/Kconfig
View File

@ -27,3 +27,15 @@ config AFS_FSCACHE
help
Say Y here if you want AFS data to be cached locally on disk through
the generic filesystem cache manager
config AFS_DEBUG_CURSOR
bool "AFS server cursor debugging"
depends on AFS_FS
help
Say Y here to cause the contents of a server cursor to be dumped to
the dmesg log if the server rotation algorithm fails to successfully
contact a server.
See <file:Documentation/filesystems/afs.txt> for more information.
If unsure, say N.

2
fs/afs/addr_list.c
View File

@ -358,6 +358,8 @@ bool afs_iterate_addresses(struct afs_addr_cursor *ac)
if (!ac->alist)
return false;
ac->nr_iterations++;
if (ac->begun) {
ac->index++;
if (ac->index == ac->alist->nr_addrs)

3
fs/afs/internal.h
View File

@ -660,6 +660,7 @@ struct afs_addr_cursor {
short error;
bool begun; /* T if we've begun iteration */
bool responded; /* T if the current address responded */
unsigned short nr_iterations; /* Number of address iterations */
};
/*
@ -677,6 +678,7 @@ struct afs_vl_cursor {
#define AFS_VL_CURSOR_STOP 0x0001 /* Set to cease iteration */
#define AFS_VL_CURSOR_RETRY 0x0002 /* Set to do a retry */
#define AFS_VL_CURSOR_RETRIED 0x0004 /* Set if started a retry */
unsigned short nr_iterations; /* Number of server iterations */
};
/*
@ -700,6 +702,7 @@ struct afs_fs_cursor {
#define AFS_FS_CURSOR_VNOVOL 0x0008 /* Set if seen VNOVOL */
#define AFS_FS_CURSOR_CUR_ONLY 0x0010 /* Set if current server only (file lock held) */
#define AFS_FS_CURSOR_NO_VSLEEP 0x0020 /* Set to prevent sleep on VBUSY, VOFFLINE, ... */
unsigned short nr_iterations; /* Number of server iterations */
};
/*

57
fs/afs/rotate.c
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@ -156,6 +156,8 @@ bool afs_select_fileserver(struct afs_fs_cursor *fc)
return false;
}
fc->nr_iterations++;
/* Evaluate the result of the previous operation, if there was one. */
switch (error) {
case SHRT_MAX:
@ -519,6 +521,56 @@ iterate_address:
return false;
}
/*
* Dump cursor state in the case of the error being EDESTADDRREQ.
*/
static void afs_dump_edestaddrreq(const struct afs_fs_cursor *fc)
{
static int count;
int i;
if (!IS_ENABLED(CONFIG_AFS_DEBUG_CURSOR) || count > 3)
return;
count++;
rcu_read_lock();
pr_notice("EDESTADDR occurred\n");
pr_notice("FC: cbb=%x cbb2=%x fl=%hx err=%hd\n",
fc->cb_break, fc->cb_break_2, fc->flags, fc->error);
pr_notice("FC: st=%u ix=%u ni=%u\n",
fc->start, fc->index, fc->nr_iterations);
if (fc->server_list) {
const struct afs_server_list *sl = fc->server_list;
pr_notice("FC: SL nr=%u ix=%u vnov=%hx\n",
sl->nr_servers, sl->index, sl->vnovol_mask);
for (i = 0; i < sl->nr_servers; i++) {
const struct afs_server *s = sl->servers[i].server;
pr_notice("FC: server fl=%lx av=%u %pU\n",
s->flags, s->addr_version, &s->uuid);
if (s->addresses) {
const struct afs_addr_list *a =
rcu_dereference(s->addresses);
pr_notice("FC: - av=%u nr=%u/%u/%u ax=%u\n",
a->version,
a->nr_ipv4, a->nr_addrs, a->max_addrs,
a->index);
pr_notice("FC: - pr=%lx yf=%lx\n",
a->probed, a->yfs);
if (a == fc->ac.alist)
pr_notice("FC: - current\n");
}
}
}
pr_notice("AC: as=%u ax=%u ac=%d er=%d b=%u r=%u ni=%u\n",
fc->ac.start, fc->ac.index, fc->ac.abort_code, fc->ac.error,
fc->ac.begun, fc->ac.responded, fc->ac.nr_iterations);
rcu_read_unlock();
}
/*
* Tidy up a filesystem cursor and unlock the vnode.
*/
@ -526,6 +578,11 @@ int afs_end_vnode_operation(struct afs_fs_cursor *fc)
{
struct afs_net *net = afs_v2net(fc->vnode);
if (fc->error == -EDESTADDRREQ ||
fc->error == -ENETUNREACH ||
fc->error == -EHOSTUNREACH)
afs_dump_edestaddrreq(fc);
mutex_unlock(&fc->vnode->io_lock);
afs_end_cursor(&fc->ac);

53
fs/afs/vl_rotate.c
View File

@ -83,6 +83,8 @@ bool afs_select_vlserver(struct afs_vl_cursor *vc)
return false;
}
vc->nr_iterations++;
/* Evaluate the result of the previous operation, if there was one. */
switch (error) {
case SHRT_MAX:
@ -234,6 +236,52 @@ failed:
return false;
}
/*
* Dump cursor state in the case of the error being EDESTADDRREQ.
*/
static void afs_vl_dump_edestaddrreq(const struct afs_vl_cursor *vc)
{
static int count;
int i;
if (!IS_ENABLED(CONFIG_AFS_DEBUG_CURSOR) || count > 3)
return;
count++;
rcu_read_lock();
pr_notice("EDESTADDR occurred\n");
pr_notice("VC: st=%u ix=%u ni=%hu fl=%hx err=%hd\n",
vc->start, vc->index, vc->nr_iterations, vc->flags, vc->error);
if (vc->server_list) {
const struct afs_vlserver_list *sl = vc->server_list;
pr_notice("VC: SL nr=%u ix=%u\n",
sl->nr_servers, sl->index);
for (i = 0; i < sl->nr_servers; i++) {
const struct afs_vlserver *s = sl->servers[i].server;
pr_notice("VC: server fl=%lx %s+%hu\n",
s->flags, s->name, s->port);
if (s->addresses) {
const struct afs_addr_list *a =
rcu_dereference(s->addresses);
pr_notice("VC: - av=%u nr=%u/%u/%u ax=%u\n",
a->version,
a->nr_ipv4, a->nr_addrs, a->max_addrs,
a->index);
pr_notice("VC: - pr=%lx yf=%lx\n",
a->probed, a->yfs);
if (a == vc->ac.alist)
pr_notice("VC: - current\n");
}
}
}
pr_notice("AC: as=%u ax=%u ac=%d er=%d b=%u r=%u ni=%hu\n",
vc->ac.start, vc->ac.index, vc->ac.abort_code, vc->ac.error,
vc->ac.begun, vc->ac.responded, vc->ac.nr_iterations);
rcu_read_unlock();
}
/*
* Tidy up a volume location server cursor and unlock the vnode.
*/
@ -241,6 +289,11 @@ int afs_end_vlserver_operation(struct afs_vl_cursor *vc)
{
struct afs_net *net = vc->cell->net;
if (vc->error == -EDESTADDRREQ ||
vc->error == -ENETUNREACH ||
vc->error == -EHOSTUNREACH)
afs_vl_dump_edestaddrreq(vc);
afs_end_cursor(&vc->ac);
afs_put_vlserverlist(net, vc->server_list);