kernel-ark/fs/gfs2/lock_dlm.c
Steven Whitehouse a245769f25 GFS2: glock statistics gathering
The stats are divided into two sets: those relating to the
super block and those relating to an individual glock. The
super block stats are done on a per cpu basis in order to
try and reduce the overhead of gathering them. They are also
further divided by glock type.

In the case of both the super block and glock statistics,
the same information is gathered in each case. The super
block statistics are used to provide default values for
most of the glock statistics, so that newly created glocks
should have, as far as possible, a sensible starting point.

The statistics are divided into three pairs of mean and
variance, plus two counters. The mean/variance pairs are
smoothed exponential estimates and the algorithm used is
one which will be very familiar to those used to calculation
of round trip times in network code.

The three pairs of mean/variance measure the following
things:

 1. DLM lock time (non-blocking requests)
 2. DLM lock time (blocking requests)
 3. Inter-request time (again to the DLM)

A non-blocking request is one which will complete right
away, whatever the state of the DLM lock in question. That
currently means any requests when (a) the current state of
the lock is exclusive (b) the requested state is either null
or unlocked or (c) the "try lock" flag is set. A blocking
request covers all the other lock requests.

There are two counters. The first is there primarily to show
how many lock requests have been made, and thus how much data
has gone into the mean/variance calculations. The other counter
is counting queueing of holders at the top layer of the glock
code. Hopefully that number will be a lot larger than the number
of dlm lock requests issued.

So why gather these statistics? There are several reasons
we'd like to get a better idea of these timings:

1. To be able to better set the glock "min hold time"
2. To spot performance issues more easily
3. To improve the algorithm for selecting resource groups for
allocation (to base it on lock wait time, rather than blindly
using a "try lock")
Due to the smoothing action of the updates, a step change in
some input quantity being sampled will only fully be taken
into account after 8 samples (or 4 for the variance) and this
needs to be carefully considered when interpreting the
results.

Knowing both the time it takes a lock request to complete and
the average time between lock requests for a glock means we
can compute the total percentage of the time for which the
node is able to use a glock vs. time that the rest of the
cluster has its share. That will be very useful when setting
the lock min hold time.

The other point to remember is that all times are in
nanoseconds. Great care has been taken to ensure that we
measure exactly the quantities that we want, as accurately
as possible. There are always inaccuracies in any
measuring system, but I hope this is as accurate as we
can reasonably make it.

Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2012-02-28 17:09:42 +00:00

1322 lines
38 KiB
C

/*
* Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved.
* Copyright 2004-2011 Red Hat, Inc.
*
* This copyrighted material is made available to anyone wishing to use,
* modify, copy, or redistribute it subject to the terms and conditions
* of the GNU General Public License version 2.
*/
#include <linux/fs.h>
#include <linux/dlm.h>
#include <linux/slab.h>
#include <linux/types.h>
#include <linux/delay.h>
#include <linux/gfs2_ondisk.h>
#include "incore.h"
#include "glock.h"
#include "util.h"
#include "sys.h"
#include "trace_gfs2.h"
extern struct workqueue_struct *gfs2_control_wq;
/**
* gfs2_update_stats - Update time based stats
* @mv: Pointer to mean/variance structure to update
* @sample: New data to include
*
* @delta is the difference between the current rtt sample and the
* running average srtt. We add 1/8 of that to the srtt in order to
* update the current srtt estimate. The varience estimate is a bit
* more complicated. We subtract the abs value of the @delta from
* the current variance estimate and add 1/4 of that to the running
* total.
*
* Note that the index points at the array entry containing the smoothed
* mean value, and the variance is always in the following entry
*
* Reference: TCP/IP Illustrated, vol 2, p. 831,832
* All times are in units of integer nanoseconds. Unlike the TCP/IP case,
* they are not scaled fixed point.
*/
static inline void gfs2_update_stats(struct gfs2_lkstats *s, unsigned index,
s64 sample)
{
s64 delta = sample - s->stats[index];
s->stats[index] += (delta >> 3);
index++;
s->stats[index] += ((abs64(delta) - s->stats[index]) >> 2);
}
/**
* gfs2_update_reply_times - Update locking statistics
* @gl: The glock to update
*
* This assumes that gl->gl_dstamp has been set earlier.
*
* The rtt (lock round trip time) is an estimate of the time
* taken to perform a dlm lock request. We update it on each
* reply from the dlm.
*
* The blocking flag is set on the glock for all dlm requests
* which may potentially block due to lock requests from other nodes.
* DLM requests where the current lock state is exclusive, the
* requested state is null (or unlocked) or where the TRY or
* TRY_1CB flags are set are classified as non-blocking. All
* other DLM requests are counted as (potentially) blocking.
*/
static inline void gfs2_update_reply_times(struct gfs2_glock *gl)
{
struct gfs2_pcpu_lkstats *lks;
const unsigned gltype = gl->gl_name.ln_type;
unsigned index = test_bit(GLF_BLOCKING, &gl->gl_flags) ?
GFS2_LKS_SRTTB : GFS2_LKS_SRTT;
s64 rtt;
preempt_disable();
rtt = ktime_to_ns(ktime_sub(ktime_get_real(), gl->gl_dstamp));
lks = this_cpu_ptr(gl->gl_sbd->sd_lkstats);
gfs2_update_stats(&gl->gl_stats, index, rtt); /* Local */
gfs2_update_stats(&lks->lkstats[gltype], index, rtt); /* Global */
preempt_enable();
trace_gfs2_glock_lock_time(gl, rtt);
}
/**
* gfs2_update_request_times - Update locking statistics
* @gl: The glock to update
*
* The irt (lock inter-request times) measures the average time
* between requests to the dlm. It is updated immediately before
* each dlm call.
*/
static inline void gfs2_update_request_times(struct gfs2_glock *gl)
{
struct gfs2_pcpu_lkstats *lks;
const unsigned gltype = gl->gl_name.ln_type;
ktime_t dstamp;
s64 irt;
preempt_disable();
dstamp = gl->gl_dstamp;
gl->gl_dstamp = ktime_get_real();
irt = ktime_to_ns(ktime_sub(gl->gl_dstamp, dstamp));
lks = this_cpu_ptr(gl->gl_sbd->sd_lkstats);
gfs2_update_stats(&gl->gl_stats, GFS2_LKS_SIRT, irt); /* Local */
gfs2_update_stats(&lks->lkstats[gltype], GFS2_LKS_SIRT, irt); /* Global */
preempt_enable();
}
static void gdlm_ast(void *arg)
{
struct gfs2_glock *gl = arg;
unsigned ret = gl->gl_state;
gfs2_update_reply_times(gl);
BUG_ON(gl->gl_lksb.sb_flags & DLM_SBF_DEMOTED);
if (gl->gl_lksb.sb_flags & DLM_SBF_VALNOTVALID)
memset(gl->gl_lvb, 0, GDLM_LVB_SIZE);
switch (gl->gl_lksb.sb_status) {
case -DLM_EUNLOCK: /* Unlocked, so glock can be freed */
gfs2_glock_free(gl);
return;
case -DLM_ECANCEL: /* Cancel while getting lock */
ret |= LM_OUT_CANCELED;
goto out;
case -EAGAIN: /* Try lock fails */
case -EDEADLK: /* Deadlock detected */
goto out;
case -ETIMEDOUT: /* Canceled due to timeout */
ret |= LM_OUT_ERROR;
goto out;
case 0: /* Success */
break;
default: /* Something unexpected */
BUG();
}
ret = gl->gl_req;
if (gl->gl_lksb.sb_flags & DLM_SBF_ALTMODE) {
if (gl->gl_req == LM_ST_SHARED)
ret = LM_ST_DEFERRED;
else if (gl->gl_req == LM_ST_DEFERRED)
ret = LM_ST_SHARED;
else
BUG();
}
set_bit(GLF_INITIAL, &gl->gl_flags);
gfs2_glock_complete(gl, ret);
return;
out:
if (!test_bit(GLF_INITIAL, &gl->gl_flags))
gl->gl_lksb.sb_lkid = 0;
gfs2_glock_complete(gl, ret);
}
static void gdlm_bast(void *arg, int mode)
{
struct gfs2_glock *gl = arg;
switch (mode) {
case DLM_LOCK_EX:
gfs2_glock_cb(gl, LM_ST_UNLOCKED);
break;
case DLM_LOCK_CW:
gfs2_glock_cb(gl, LM_ST_DEFERRED);
break;
case DLM_LOCK_PR:
gfs2_glock_cb(gl, LM_ST_SHARED);
break;
default:
printk(KERN_ERR "unknown bast mode %d", mode);
BUG();
}
}
/* convert gfs lock-state to dlm lock-mode */
static int make_mode(const unsigned int lmstate)
{
switch (lmstate) {
case LM_ST_UNLOCKED:
return DLM_LOCK_NL;
case LM_ST_EXCLUSIVE:
return DLM_LOCK_EX;
case LM_ST_DEFERRED:
return DLM_LOCK_CW;
case LM_ST_SHARED:
return DLM_LOCK_PR;
}
printk(KERN_ERR "unknown LM state %d", lmstate);
BUG();
return -1;
}
static u32 make_flags(const u32 lkid, const unsigned int gfs_flags,
const int req)
{
u32 lkf = DLM_LKF_VALBLK;
if (gfs_flags & LM_FLAG_TRY)
lkf |= DLM_LKF_NOQUEUE;
if (gfs_flags & LM_FLAG_TRY_1CB) {
lkf |= DLM_LKF_NOQUEUE;
lkf |= DLM_LKF_NOQUEUEBAST;
}
if (gfs_flags & LM_FLAG_PRIORITY) {
lkf |= DLM_LKF_NOORDER;
lkf |= DLM_LKF_HEADQUE;
}
if (gfs_flags & LM_FLAG_ANY) {
if (req == DLM_LOCK_PR)
lkf |= DLM_LKF_ALTCW;
else if (req == DLM_LOCK_CW)
lkf |= DLM_LKF_ALTPR;
else
BUG();
}
if (lkid != 0)
lkf |= DLM_LKF_CONVERT;
return lkf;
}
static void gfs2_reverse_hex(char *c, u64 value)
{
while (value) {
*c-- = hex_asc[value & 0x0f];
value >>= 4;
}
}
static int gdlm_lock(struct gfs2_glock *gl, unsigned int req_state,
unsigned int flags)
{
struct lm_lockstruct *ls = &gl->gl_sbd->sd_lockstruct;
int req;
u32 lkf;
char strname[GDLM_STRNAME_BYTES] = "";
req = make_mode(req_state);
lkf = make_flags(gl->gl_lksb.sb_lkid, flags, req);
gfs2_glstats_inc(gl, GFS2_LKS_DCOUNT);
gfs2_sbstats_inc(gl, GFS2_LKS_DCOUNT);
if (gl->gl_lksb.sb_lkid) {
gfs2_update_request_times(gl);
} else {
memset(strname, ' ', GDLM_STRNAME_BYTES - 1);
strname[GDLM_STRNAME_BYTES - 1] = '\0';
gfs2_reverse_hex(strname + 7, gl->gl_name.ln_type);
gfs2_reverse_hex(strname + 23, gl->gl_name.ln_number);
gl->gl_dstamp = ktime_get_real();
}
/*
* Submit the actual lock request.
*/
return dlm_lock(ls->ls_dlm, req, &gl->gl_lksb, lkf, strname,
GDLM_STRNAME_BYTES - 1, 0, gdlm_ast, gl, gdlm_bast);
}
static void gdlm_put_lock(struct gfs2_glock *gl)
{
struct gfs2_sbd *sdp = gl->gl_sbd;
struct lm_lockstruct *ls = &sdp->sd_lockstruct;
int error;
if (gl->gl_lksb.sb_lkid == 0) {
gfs2_glock_free(gl);
return;
}
clear_bit(GLF_BLOCKING, &gl->gl_flags);
gfs2_glstats_inc(gl, GFS2_LKS_DCOUNT);
gfs2_sbstats_inc(gl, GFS2_LKS_DCOUNT);
gfs2_update_request_times(gl);
error = dlm_unlock(ls->ls_dlm, gl->gl_lksb.sb_lkid, DLM_LKF_VALBLK,
NULL, gl);
if (error) {
printk(KERN_ERR "gdlm_unlock %x,%llx err=%d\n",
gl->gl_name.ln_type,
(unsigned long long)gl->gl_name.ln_number, error);
return;
}
}
static void gdlm_cancel(struct gfs2_glock *gl)
{
struct lm_lockstruct *ls = &gl->gl_sbd->sd_lockstruct;
dlm_unlock(ls->ls_dlm, gl->gl_lksb.sb_lkid, DLM_LKF_CANCEL, NULL, gl);
}
/*
* dlm/gfs2 recovery coordination using dlm_recover callbacks
*
* 1. dlm_controld sees lockspace members change
* 2. dlm_controld blocks dlm-kernel locking activity
* 3. dlm_controld within dlm-kernel notifies gfs2 (recover_prep)
* 4. dlm_controld starts and finishes its own user level recovery
* 5. dlm_controld starts dlm-kernel dlm_recoverd to do kernel recovery
* 6. dlm_recoverd notifies gfs2 of failed nodes (recover_slot)
* 7. dlm_recoverd does its own lock recovery
* 8. dlm_recoverd unblocks dlm-kernel locking activity
* 9. dlm_recoverd notifies gfs2 when done (recover_done with new generation)
* 10. gfs2_control updates control_lock lvb with new generation and jid bits
* 11. gfs2_control enqueues journals for gfs2_recover to recover (maybe none)
* 12. gfs2_recover dequeues and recovers journals of failed nodes
* 13. gfs2_recover provides recovery results to gfs2_control (recovery_result)
* 14. gfs2_control updates control_lock lvb jid bits for recovered journals
* 15. gfs2_control unblocks normal locking when all journals are recovered
*
* - failures during recovery
*
* recover_prep() may set BLOCK_LOCKS (step 3) again before gfs2_control
* clears BLOCK_LOCKS (step 15), e.g. another node fails while still
* recovering for a prior failure. gfs2_control needs a way to detect
* this so it can leave BLOCK_LOCKS set in step 15. This is managed using
* the recover_block and recover_start values.
*
* recover_done() provides a new lockspace generation number each time it
* is called (step 9). This generation number is saved as recover_start.
* When recover_prep() is called, it sets BLOCK_LOCKS and sets
* recover_block = recover_start. So, while recover_block is equal to
* recover_start, BLOCK_LOCKS should remain set. (recover_spin must
* be held around the BLOCK_LOCKS/recover_block/recover_start logic.)
*
* - more specific gfs2 steps in sequence above
*
* 3. recover_prep sets BLOCK_LOCKS and sets recover_block = recover_start
* 6. recover_slot records any failed jids (maybe none)
* 9. recover_done sets recover_start = new generation number
* 10. gfs2_control sets control_lock lvb = new gen + bits for failed jids
* 12. gfs2_recover does journal recoveries for failed jids identified above
* 14. gfs2_control clears control_lock lvb bits for recovered jids
* 15. gfs2_control checks if recover_block == recover_start (step 3 occured
* again) then do nothing, otherwise if recover_start > recover_block
* then clear BLOCK_LOCKS.
*
* - parallel recovery steps across all nodes
*
* All nodes attempt to update the control_lock lvb with the new generation
* number and jid bits, but only the first to get the control_lock EX will
* do so; others will see that it's already done (lvb already contains new
* generation number.)
*
* . All nodes get the same recover_prep/recover_slot/recover_done callbacks
* . All nodes attempt to set control_lock lvb gen + bits for the new gen
* . One node gets control_lock first and writes the lvb, others see it's done
* . All nodes attempt to recover jids for which they see control_lock bits set
* . One node succeeds for a jid, and that one clears the jid bit in the lvb
* . All nodes will eventually see all lvb bits clear and unblock locks
*
* - is there a problem with clearing an lvb bit that should be set
* and missing a journal recovery?
*
* 1. jid fails
* 2. lvb bit set for step 1
* 3. jid recovered for step 1
* 4. jid taken again (new mount)
* 5. jid fails (for step 4)
* 6. lvb bit set for step 5 (will already be set)
* 7. lvb bit cleared for step 3
*
* This is not a problem because the failure in step 5 does not
* require recovery, because the mount in step 4 could not have
* progressed far enough to unblock locks and access the fs. The
* control_mount() function waits for all recoveries to be complete
* for the latest lockspace generation before ever unblocking locks
* and returning. The mount in step 4 waits until the recovery in
* step 1 is done.
*
* - special case of first mounter: first node to mount the fs
*
* The first node to mount a gfs2 fs needs to check all the journals
* and recover any that need recovery before other nodes are allowed
* to mount the fs. (Others may begin mounting, but they must wait
* for the first mounter to be done before taking locks on the fs
* or accessing the fs.) This has two parts:
*
* 1. The mounted_lock tells a node it's the first to mount the fs.
* Each node holds the mounted_lock in PR while it's mounted.
* Each node tries to acquire the mounted_lock in EX when it mounts.
* If a node is granted the mounted_lock EX it means there are no
* other mounted nodes (no PR locks exist), and it is the first mounter.
* The mounted_lock is demoted to PR when first recovery is done, so
* others will fail to get an EX lock, but will get a PR lock.
*
* 2. The control_lock blocks others in control_mount() while the first
* mounter is doing first mount recovery of all journals.
* A mounting node needs to acquire control_lock in EX mode before
* it can proceed. The first mounter holds control_lock in EX while doing
* the first mount recovery, blocking mounts from other nodes, then demotes
* control_lock to NL when it's done (others_may_mount/first_done),
* allowing other nodes to continue mounting.
*
* first mounter:
* control_lock EX/NOQUEUE success
* mounted_lock EX/NOQUEUE success (no other PR, so no other mounters)
* set first=1
* do first mounter recovery
* mounted_lock EX->PR
* control_lock EX->NL, write lvb generation
*
* other mounter:
* control_lock EX/NOQUEUE success (if fail -EAGAIN, retry)
* mounted_lock EX/NOQUEUE fail -EAGAIN (expected due to other mounters PR)
* mounted_lock PR/NOQUEUE success
* read lvb generation
* control_lock EX->NL
* set first=0
*
* - mount during recovery
*
* If a node mounts while others are doing recovery (not first mounter),
* the mounting node will get its initial recover_done() callback without
* having seen any previous failures/callbacks.
*
* It must wait for all recoveries preceding its mount to be finished
* before it unblocks locks. It does this by repeating the "other mounter"
* steps above until the lvb generation number is >= its mount generation
* number (from initial recover_done) and all lvb bits are clear.
*
* - control_lock lvb format
*
* 4 bytes generation number: the latest dlm lockspace generation number
* from recover_done callback. Indicates the jid bitmap has been updated
* to reflect all slot failures through that generation.
* 4 bytes unused.
* GDLM_LVB_SIZE-8 bytes of jid bit map. If bit N is set, it indicates
* that jid N needs recovery.
*/
#define JID_BITMAP_OFFSET 8 /* 4 byte generation number + 4 byte unused */
static void control_lvb_read(struct lm_lockstruct *ls, uint32_t *lvb_gen,
char *lvb_bits)
{
uint32_t gen;
memcpy(lvb_bits, ls->ls_control_lvb, GDLM_LVB_SIZE);
memcpy(&gen, lvb_bits, sizeof(uint32_t));
*lvb_gen = le32_to_cpu(gen);
}
static void control_lvb_write(struct lm_lockstruct *ls, uint32_t lvb_gen,
char *lvb_bits)
{
uint32_t gen;
memcpy(ls->ls_control_lvb, lvb_bits, GDLM_LVB_SIZE);
gen = cpu_to_le32(lvb_gen);
memcpy(ls->ls_control_lvb, &gen, sizeof(uint32_t));
}
static int all_jid_bits_clear(char *lvb)
{
int i;
for (i = JID_BITMAP_OFFSET; i < GDLM_LVB_SIZE; i++) {
if (lvb[i])
return 0;
}
return 1;
}
static void sync_wait_cb(void *arg)
{
struct lm_lockstruct *ls = arg;
complete(&ls->ls_sync_wait);
}
static int sync_unlock(struct gfs2_sbd *sdp, struct dlm_lksb *lksb, char *name)
{
struct lm_lockstruct *ls = &sdp->sd_lockstruct;
int error;
error = dlm_unlock(ls->ls_dlm, lksb->sb_lkid, 0, lksb, ls);
if (error) {
fs_err(sdp, "%s lkid %x error %d\n",
name, lksb->sb_lkid, error);
return error;
}
wait_for_completion(&ls->ls_sync_wait);
if (lksb->sb_status != -DLM_EUNLOCK) {
fs_err(sdp, "%s lkid %x status %d\n",
name, lksb->sb_lkid, lksb->sb_status);
return -1;
}
return 0;
}
static int sync_lock(struct gfs2_sbd *sdp, int mode, uint32_t flags,
unsigned int num, struct dlm_lksb *lksb, char *name)
{
struct lm_lockstruct *ls = &sdp->sd_lockstruct;
char strname[GDLM_STRNAME_BYTES];
int error, status;
memset(strname, 0, GDLM_STRNAME_BYTES);
snprintf(strname, GDLM_STRNAME_BYTES, "%8x%16x", LM_TYPE_NONDISK, num);
error = dlm_lock(ls->ls_dlm, mode, lksb, flags,
strname, GDLM_STRNAME_BYTES - 1,
0, sync_wait_cb, ls, NULL);
if (error) {
fs_err(sdp, "%s lkid %x flags %x mode %d error %d\n",
name, lksb->sb_lkid, flags, mode, error);
return error;
}
wait_for_completion(&ls->ls_sync_wait);
status = lksb->sb_status;
if (status && status != -EAGAIN) {
fs_err(sdp, "%s lkid %x flags %x mode %d status %d\n",
name, lksb->sb_lkid, flags, mode, status);
}
return status;
}
static int mounted_unlock(struct gfs2_sbd *sdp)
{
struct lm_lockstruct *ls = &sdp->sd_lockstruct;
return sync_unlock(sdp, &ls->ls_mounted_lksb, "mounted_lock");
}
static int mounted_lock(struct gfs2_sbd *sdp, int mode, uint32_t flags)
{
struct lm_lockstruct *ls = &sdp->sd_lockstruct;
return sync_lock(sdp, mode, flags, GFS2_MOUNTED_LOCK,
&ls->ls_mounted_lksb, "mounted_lock");
}
static int control_unlock(struct gfs2_sbd *sdp)
{
struct lm_lockstruct *ls = &sdp->sd_lockstruct;
return sync_unlock(sdp, &ls->ls_control_lksb, "control_lock");
}
static int control_lock(struct gfs2_sbd *sdp, int mode, uint32_t flags)
{
struct lm_lockstruct *ls = &sdp->sd_lockstruct;
return sync_lock(sdp, mode, flags, GFS2_CONTROL_LOCK,
&ls->ls_control_lksb, "control_lock");
}
static void gfs2_control_func(struct work_struct *work)
{
struct gfs2_sbd *sdp = container_of(work, struct gfs2_sbd, sd_control_work.work);
struct lm_lockstruct *ls = &sdp->sd_lockstruct;
char lvb_bits[GDLM_LVB_SIZE];
uint32_t block_gen, start_gen, lvb_gen, flags;
int recover_set = 0;
int write_lvb = 0;
int recover_size;
int i, error;
spin_lock(&ls->ls_recover_spin);
/*
* No MOUNT_DONE means we're still mounting; control_mount()
* will set this flag, after which this thread will take over
* all further clearing of BLOCK_LOCKS.
*
* FIRST_MOUNT means this node is doing first mounter recovery,
* for which recovery control is handled by
* control_mount()/control_first_done(), not this thread.
*/
if (!test_bit(DFL_MOUNT_DONE, &ls->ls_recover_flags) ||
test_bit(DFL_FIRST_MOUNT, &ls->ls_recover_flags)) {
spin_unlock(&ls->ls_recover_spin);
return;
}
block_gen = ls->ls_recover_block;
start_gen = ls->ls_recover_start;
spin_unlock(&ls->ls_recover_spin);
/*
* Equal block_gen and start_gen implies we are between
* recover_prep and recover_done callbacks, which means
* dlm recovery is in progress and dlm locking is blocked.
* There's no point trying to do any work until recover_done.
*/
if (block_gen == start_gen)
return;
/*
* Propagate recover_submit[] and recover_result[] to lvb:
* dlm_recoverd adds to recover_submit[] jids needing recovery
* gfs2_recover adds to recover_result[] journal recovery results
*
* set lvb bit for jids in recover_submit[] if the lvb has not
* yet been updated for the generation of the failure
*
* clear lvb bit for jids in recover_result[] if the result of
* the journal recovery is SUCCESS
*/
error = control_lock(sdp, DLM_LOCK_EX, DLM_LKF_CONVERT|DLM_LKF_VALBLK);
if (error) {
fs_err(sdp, "control lock EX error %d\n", error);
return;
}
control_lvb_read(ls, &lvb_gen, lvb_bits);
spin_lock(&ls->ls_recover_spin);
if (block_gen != ls->ls_recover_block ||
start_gen != ls->ls_recover_start) {
fs_info(sdp, "recover generation %u block1 %u %u\n",
start_gen, block_gen, ls->ls_recover_block);
spin_unlock(&ls->ls_recover_spin);
control_lock(sdp, DLM_LOCK_NL, DLM_LKF_CONVERT);
return;
}
recover_size = ls->ls_recover_size;
if (lvb_gen <= start_gen) {
/*
* Clear lvb bits for jids we've successfully recovered.
* Because all nodes attempt to recover failed journals,
* a journal can be recovered multiple times successfully
* in succession. Only the first will really do recovery,
* the others find it clean, but still report a successful
* recovery. So, another node may have already recovered
* the jid and cleared the lvb bit for it.
*/
for (i = 0; i < recover_size; i++) {
if (ls->ls_recover_result[i] != LM_RD_SUCCESS)
continue;
ls->ls_recover_result[i] = 0;
if (!test_bit_le(i, lvb_bits + JID_BITMAP_OFFSET))
continue;
__clear_bit_le(i, lvb_bits + JID_BITMAP_OFFSET);
write_lvb = 1;
}
}
if (lvb_gen == start_gen) {
/*
* Failed slots before start_gen are already set in lvb.
*/
for (i = 0; i < recover_size; i++) {
if (!ls->ls_recover_submit[i])
continue;
if (ls->ls_recover_submit[i] < lvb_gen)
ls->ls_recover_submit[i] = 0;
}
} else if (lvb_gen < start_gen) {
/*
* Failed slots before start_gen are not yet set in lvb.
*/
for (i = 0; i < recover_size; i++) {
if (!ls->ls_recover_submit[i])
continue;
if (ls->ls_recover_submit[i] < start_gen) {
ls->ls_recover_submit[i] = 0;
__set_bit_le(i, lvb_bits + JID_BITMAP_OFFSET);
}
}
/* even if there are no bits to set, we need to write the
latest generation to the lvb */
write_lvb = 1;
} else {
/*
* we should be getting a recover_done() for lvb_gen soon
*/
}
spin_unlock(&ls->ls_recover_spin);
if (write_lvb) {
control_lvb_write(ls, start_gen, lvb_bits);
flags = DLM_LKF_CONVERT | DLM_LKF_VALBLK;
} else {
flags = DLM_LKF_CONVERT;
}
error = control_lock(sdp, DLM_LOCK_NL, flags);
if (error) {
fs_err(sdp, "control lock NL error %d\n", error);
return;
}
/*
* Everyone will see jid bits set in the lvb, run gfs2_recover_set(),
* and clear a jid bit in the lvb if the recovery is a success.
* Eventually all journals will be recovered, all jid bits will
* be cleared in the lvb, and everyone will clear BLOCK_LOCKS.
*/
for (i = 0; i < recover_size; i++) {
if (test_bit_le(i, lvb_bits + JID_BITMAP_OFFSET)) {
fs_info(sdp, "recover generation %u jid %d\n",
start_gen, i);
gfs2_recover_set(sdp, i);
recover_set++;
}
}
if (recover_set)
return;
/*
* No more jid bits set in lvb, all recovery is done, unblock locks
* (unless a new recover_prep callback has occured blocking locks
* again while working above)
*/
spin_lock(&ls->ls_recover_spin);
if (ls->ls_recover_block == block_gen &&
ls->ls_recover_start == start_gen) {
clear_bit(DFL_BLOCK_LOCKS, &ls->ls_recover_flags);
spin_unlock(&ls->ls_recover_spin);
fs_info(sdp, "recover generation %u done\n", start_gen);
gfs2_glock_thaw(sdp);
} else {
fs_info(sdp, "recover generation %u block2 %u %u\n",
start_gen, block_gen, ls->ls_recover_block);
spin_unlock(&ls->ls_recover_spin);
}
}
static int control_mount(struct gfs2_sbd *sdp)
{
struct lm_lockstruct *ls = &sdp->sd_lockstruct;
char lvb_bits[GDLM_LVB_SIZE];
uint32_t start_gen, block_gen, mount_gen, lvb_gen;
int mounted_mode;
int retries = 0;
int error;
memset(&ls->ls_mounted_lksb, 0, sizeof(struct dlm_lksb));
memset(&ls->ls_control_lksb, 0, sizeof(struct dlm_lksb));
memset(&ls->ls_control_lvb, 0, GDLM_LVB_SIZE);
ls->ls_control_lksb.sb_lvbptr = ls->ls_control_lvb;
init_completion(&ls->ls_sync_wait);
set_bit(DFL_BLOCK_LOCKS, &ls->ls_recover_flags);
error = control_lock(sdp, DLM_LOCK_NL, DLM_LKF_VALBLK);
if (error) {
fs_err(sdp, "control_mount control_lock NL error %d\n", error);
return error;
}
error = mounted_lock(sdp, DLM_LOCK_NL, 0);
if (error) {
fs_err(sdp, "control_mount mounted_lock NL error %d\n", error);
control_unlock(sdp);
return error;
}
mounted_mode = DLM_LOCK_NL;
restart:
if (retries++ && signal_pending(current)) {
error = -EINTR;
goto fail;
}
/*
* We always start with both locks in NL. control_lock is
* demoted to NL below so we don't need to do it here.
*/
if (mounted_mode != DLM_LOCK_NL) {
error = mounted_lock(sdp, DLM_LOCK_NL, DLM_LKF_CONVERT);
if (error)
goto fail;
mounted_mode = DLM_LOCK_NL;
}
/*
* Other nodes need to do some work in dlm recovery and gfs2_control
* before the recover_done and control_lock will be ready for us below.
* A delay here is not required but often avoids having to retry.
*/
msleep_interruptible(500);
/*
* Acquire control_lock in EX and mounted_lock in either EX or PR.
* control_lock lvb keeps track of any pending journal recoveries.
* mounted_lock indicates if any other nodes have the fs mounted.
*/
error = control_lock(sdp, DLM_LOCK_EX, DLM_LKF_CONVERT|DLM_LKF_NOQUEUE|DLM_LKF_VALBLK);
if (error == -EAGAIN) {
goto restart;
} else if (error) {
fs_err(sdp, "control_mount control_lock EX error %d\n", error);
goto fail;
}
error = mounted_lock(sdp, DLM_LOCK_EX, DLM_LKF_CONVERT|DLM_LKF_NOQUEUE);
if (!error) {
mounted_mode = DLM_LOCK_EX;
goto locks_done;
} else if (error != -EAGAIN) {
fs_err(sdp, "control_mount mounted_lock EX error %d\n", error);
goto fail;
}
error = mounted_lock(sdp, DLM_LOCK_PR, DLM_LKF_CONVERT|DLM_LKF_NOQUEUE);
if (!error) {
mounted_mode = DLM_LOCK_PR;
goto locks_done;
} else {
/* not even -EAGAIN should happen here */
fs_err(sdp, "control_mount mounted_lock PR error %d\n", error);
goto fail;
}
locks_done:
/*
* If we got both locks above in EX, then we're the first mounter.
* If not, then we need to wait for the control_lock lvb to be
* updated by other mounted nodes to reflect our mount generation.
*
* In simple first mounter cases, first mounter will see zero lvb_gen,
* but in cases where all existing nodes leave/fail before mounting
* nodes finish control_mount, then all nodes will be mounting and
* lvb_gen will be non-zero.
*/
control_lvb_read(ls, &lvb_gen, lvb_bits);
if (lvb_gen == 0xFFFFFFFF) {
/* special value to force mount attempts to fail */
fs_err(sdp, "control_mount control_lock disabled\n");
error = -EINVAL;
goto fail;
}
if (mounted_mode == DLM_LOCK_EX) {
/* first mounter, keep both EX while doing first recovery */
spin_lock(&ls->ls_recover_spin);
clear_bit(DFL_BLOCK_LOCKS, &ls->ls_recover_flags);
set_bit(DFL_MOUNT_DONE, &ls->ls_recover_flags);
set_bit(DFL_FIRST_MOUNT, &ls->ls_recover_flags);
spin_unlock(&ls->ls_recover_spin);
fs_info(sdp, "first mounter control generation %u\n", lvb_gen);
return 0;
}
error = control_lock(sdp, DLM_LOCK_NL, DLM_LKF_CONVERT);
if (error)
goto fail;
/*
* We are not first mounter, now we need to wait for the control_lock
* lvb generation to be >= the generation from our first recover_done
* and all lvb bits to be clear (no pending journal recoveries.)
*/
if (!all_jid_bits_clear(lvb_bits)) {
/* journals need recovery, wait until all are clear */
fs_info(sdp, "control_mount wait for journal recovery\n");
goto restart;
}
spin_lock(&ls->ls_recover_spin);
block_gen = ls->ls_recover_block;
start_gen = ls->ls_recover_start;
mount_gen = ls->ls_recover_mount;
if (lvb_gen < mount_gen) {
/* wait for mounted nodes to update control_lock lvb to our
generation, which might include new recovery bits set */
fs_info(sdp, "control_mount wait1 block %u start %u mount %u "
"lvb %u flags %lx\n", block_gen, start_gen, mount_gen,
lvb_gen, ls->ls_recover_flags);
spin_unlock(&ls->ls_recover_spin);
goto restart;
}
if (lvb_gen != start_gen) {
/* wait for mounted nodes to update control_lock lvb to the
latest recovery generation */
fs_info(sdp, "control_mount wait2 block %u start %u mount %u "
"lvb %u flags %lx\n", block_gen, start_gen, mount_gen,
lvb_gen, ls->ls_recover_flags);
spin_unlock(&ls->ls_recover_spin);
goto restart;
}
if (block_gen == start_gen) {
/* dlm recovery in progress, wait for it to finish */
fs_info(sdp, "control_mount wait3 block %u start %u mount %u "
"lvb %u flags %lx\n", block_gen, start_gen, mount_gen,
lvb_gen, ls->ls_recover_flags);
spin_unlock(&ls->ls_recover_spin);
goto restart;
}
clear_bit(DFL_BLOCK_LOCKS, &ls->ls_recover_flags);
set_bit(DFL_MOUNT_DONE, &ls->ls_recover_flags);
memset(ls->ls_recover_submit, 0, ls->ls_recover_size*sizeof(uint32_t));
memset(ls->ls_recover_result, 0, ls->ls_recover_size*sizeof(uint32_t));
spin_unlock(&ls->ls_recover_spin);
return 0;
fail:
mounted_unlock(sdp);
control_unlock(sdp);
return error;
}
static int dlm_recovery_wait(void *word)
{
schedule();
return 0;
}
static int control_first_done(struct gfs2_sbd *sdp)
{
struct lm_lockstruct *ls = &sdp->sd_lockstruct;
char lvb_bits[GDLM_LVB_SIZE];
uint32_t start_gen, block_gen;
int error;
restart:
spin_lock(&ls->ls_recover_spin);
start_gen = ls->ls_recover_start;
block_gen = ls->ls_recover_block;
if (test_bit(DFL_BLOCK_LOCKS, &ls->ls_recover_flags) ||
!test_bit(DFL_MOUNT_DONE, &ls->ls_recover_flags) ||
!test_bit(DFL_FIRST_MOUNT, &ls->ls_recover_flags)) {
/* sanity check, should not happen */
fs_err(sdp, "control_first_done start %u block %u flags %lx\n",
start_gen, block_gen, ls->ls_recover_flags);
spin_unlock(&ls->ls_recover_spin);
control_unlock(sdp);
return -1;
}
if (start_gen == block_gen) {
/*
* Wait for the end of a dlm recovery cycle to switch from
* first mounter recovery. We can ignore any recover_slot
* callbacks between the recover_prep and next recover_done
* because we are still the first mounter and any failed nodes
* have not fully mounted, so they don't need recovery.
*/
spin_unlock(&ls->ls_recover_spin);
fs_info(sdp, "control_first_done wait gen %u\n", start_gen);
wait_on_bit(&ls->ls_recover_flags, DFL_DLM_RECOVERY,
dlm_recovery_wait, TASK_UNINTERRUPTIBLE);
goto restart;
}
clear_bit(DFL_FIRST_MOUNT, &ls->ls_recover_flags);
set_bit(DFL_FIRST_MOUNT_DONE, &ls->ls_recover_flags);
memset(ls->ls_recover_submit, 0, ls->ls_recover_size*sizeof(uint32_t));
memset(ls->ls_recover_result, 0, ls->ls_recover_size*sizeof(uint32_t));
spin_unlock(&ls->ls_recover_spin);
memset(lvb_bits, 0, sizeof(lvb_bits));
control_lvb_write(ls, start_gen, lvb_bits);
error = mounted_lock(sdp, DLM_LOCK_PR, DLM_LKF_CONVERT);
if (error)
fs_err(sdp, "control_first_done mounted PR error %d\n", error);
error = control_lock(sdp, DLM_LOCK_NL, DLM_LKF_CONVERT|DLM_LKF_VALBLK);
if (error)
fs_err(sdp, "control_first_done control NL error %d\n", error);
return error;
}
/*
* Expand static jid arrays if necessary (by increments of RECOVER_SIZE_INC)
* to accomodate the largest slot number. (NB dlm slot numbers start at 1,
* gfs2 jids start at 0, so jid = slot - 1)
*/
#define RECOVER_SIZE_INC 16
static int set_recover_size(struct gfs2_sbd *sdp, struct dlm_slot *slots,
int num_slots)
{
struct lm_lockstruct *ls = &sdp->sd_lockstruct;
uint32_t *submit = NULL;
uint32_t *result = NULL;
uint32_t old_size, new_size;
int i, max_jid;
max_jid = 0;
for (i = 0; i < num_slots; i++) {
if (max_jid < slots[i].slot - 1)
max_jid = slots[i].slot - 1;
}
old_size = ls->ls_recover_size;
if (old_size >= max_jid + 1)
return 0;
new_size = old_size + RECOVER_SIZE_INC;
submit = kzalloc(new_size * sizeof(uint32_t), GFP_NOFS);
result = kzalloc(new_size * sizeof(uint32_t), GFP_NOFS);
if (!submit || !result) {
kfree(submit);
kfree(result);
return -ENOMEM;
}
spin_lock(&ls->ls_recover_spin);
memcpy(submit, ls->ls_recover_submit, old_size * sizeof(uint32_t));
memcpy(result, ls->ls_recover_result, old_size * sizeof(uint32_t));
kfree(ls->ls_recover_submit);
kfree(ls->ls_recover_result);
ls->ls_recover_submit = submit;
ls->ls_recover_result = result;
ls->ls_recover_size = new_size;
spin_unlock(&ls->ls_recover_spin);
return 0;
}
static void free_recover_size(struct lm_lockstruct *ls)
{
kfree(ls->ls_recover_submit);
kfree(ls->ls_recover_result);
ls->ls_recover_submit = NULL;
ls->ls_recover_result = NULL;
ls->ls_recover_size = 0;
}
/* dlm calls before it does lock recovery */
static void gdlm_recover_prep(void *arg)
{
struct gfs2_sbd *sdp = arg;
struct lm_lockstruct *ls = &sdp->sd_lockstruct;
spin_lock(&ls->ls_recover_spin);
ls->ls_recover_block = ls->ls_recover_start;
set_bit(DFL_DLM_RECOVERY, &ls->ls_recover_flags);
if (!test_bit(DFL_MOUNT_DONE, &ls->ls_recover_flags) ||
test_bit(DFL_FIRST_MOUNT, &ls->ls_recover_flags)) {
spin_unlock(&ls->ls_recover_spin);
return;
}
set_bit(DFL_BLOCK_LOCKS, &ls->ls_recover_flags);
spin_unlock(&ls->ls_recover_spin);
}
/* dlm calls after recover_prep has been completed on all lockspace members;
identifies slot/jid of failed member */
static void gdlm_recover_slot(void *arg, struct dlm_slot *slot)
{
struct gfs2_sbd *sdp = arg;
struct lm_lockstruct *ls = &sdp->sd_lockstruct;
int jid = slot->slot - 1;
spin_lock(&ls->ls_recover_spin);
if (ls->ls_recover_size < jid + 1) {
fs_err(sdp, "recover_slot jid %d gen %u short size %d",
jid, ls->ls_recover_block, ls->ls_recover_size);
spin_unlock(&ls->ls_recover_spin);
return;
}
if (ls->ls_recover_submit[jid]) {
fs_info(sdp, "recover_slot jid %d gen %u prev %u",
jid, ls->ls_recover_block, ls->ls_recover_submit[jid]);
}
ls->ls_recover_submit[jid] = ls->ls_recover_block;
spin_unlock(&ls->ls_recover_spin);
}
/* dlm calls after recover_slot and after it completes lock recovery */
static void gdlm_recover_done(void *arg, struct dlm_slot *slots, int num_slots,
int our_slot, uint32_t generation)
{
struct gfs2_sbd *sdp = arg;
struct lm_lockstruct *ls = &sdp->sd_lockstruct;
/* ensure the ls jid arrays are large enough */
set_recover_size(sdp, slots, num_slots);
spin_lock(&ls->ls_recover_spin);
ls->ls_recover_start = generation;
if (!ls->ls_recover_mount) {
ls->ls_recover_mount = generation;
ls->ls_jid = our_slot - 1;
}
if (!test_bit(DFL_UNMOUNT, &ls->ls_recover_flags))
queue_delayed_work(gfs2_control_wq, &sdp->sd_control_work, 0);
clear_bit(DFL_DLM_RECOVERY, &ls->ls_recover_flags);
smp_mb__after_clear_bit();
wake_up_bit(&ls->ls_recover_flags, DFL_DLM_RECOVERY);
spin_unlock(&ls->ls_recover_spin);
}
/* gfs2_recover thread has a journal recovery result */
static void gdlm_recovery_result(struct gfs2_sbd *sdp, unsigned int jid,
unsigned int result)
{
struct lm_lockstruct *ls = &sdp->sd_lockstruct;
if (test_bit(DFL_NO_DLM_OPS, &ls->ls_recover_flags))
return;
/* don't care about the recovery of own journal during mount */
if (jid == ls->ls_jid)
return;
spin_lock(&ls->ls_recover_spin);
if (test_bit(DFL_FIRST_MOUNT, &ls->ls_recover_flags)) {
spin_unlock(&ls->ls_recover_spin);
return;
}
if (ls->ls_recover_size < jid + 1) {
fs_err(sdp, "recovery_result jid %d short size %d",
jid, ls->ls_recover_size);
spin_unlock(&ls->ls_recover_spin);
return;
}
fs_info(sdp, "recover jid %d result %s\n", jid,
result == LM_RD_GAVEUP ? "busy" : "success");
ls->ls_recover_result[jid] = result;
/* GAVEUP means another node is recovering the journal; delay our
next attempt to recover it, to give the other node a chance to
finish before trying again */
if (!test_bit(DFL_UNMOUNT, &ls->ls_recover_flags))
queue_delayed_work(gfs2_control_wq, &sdp->sd_control_work,
result == LM_RD_GAVEUP ? HZ : 0);
spin_unlock(&ls->ls_recover_spin);
}
const struct dlm_lockspace_ops gdlm_lockspace_ops = {
.recover_prep = gdlm_recover_prep,
.recover_slot = gdlm_recover_slot,
.recover_done = gdlm_recover_done,
};
static int gdlm_mount(struct gfs2_sbd *sdp, const char *table)
{
struct lm_lockstruct *ls = &sdp->sd_lockstruct;
char cluster[GFS2_LOCKNAME_LEN];
const char *fsname;
uint32_t flags;
int error, ops_result;
/*
* initialize everything
*/
INIT_DELAYED_WORK(&sdp->sd_control_work, gfs2_control_func);
spin_lock_init(&ls->ls_recover_spin);
ls->ls_recover_flags = 0;
ls->ls_recover_mount = 0;
ls->ls_recover_start = 0;
ls->ls_recover_block = 0;
ls->ls_recover_size = 0;
ls->ls_recover_submit = NULL;
ls->ls_recover_result = NULL;
error = set_recover_size(sdp, NULL, 0);
if (error)
goto fail;
/*
* prepare dlm_new_lockspace args
*/
fsname = strchr(table, ':');
if (!fsname) {
fs_info(sdp, "no fsname found\n");
error = -EINVAL;
goto fail_free;
}
memset(cluster, 0, sizeof(cluster));
memcpy(cluster, table, strlen(table) - strlen(fsname));
fsname++;
flags = DLM_LSFL_FS | DLM_LSFL_NEWEXCL;
if (ls->ls_nodir)
flags |= DLM_LSFL_NODIR;
/*
* create/join lockspace
*/
error = dlm_new_lockspace(fsname, cluster, flags, GDLM_LVB_SIZE,
&gdlm_lockspace_ops, sdp, &ops_result,
&ls->ls_dlm);
if (error) {
fs_err(sdp, "dlm_new_lockspace error %d\n", error);
goto fail_free;
}
if (ops_result < 0) {
/*
* dlm does not support ops callbacks,
* old dlm_controld/gfs_controld are used, try without ops.
*/
fs_info(sdp, "dlm lockspace ops not used\n");
free_recover_size(ls);
set_bit(DFL_NO_DLM_OPS, &ls->ls_recover_flags);
return 0;
}
if (!test_bit(SDF_NOJOURNALID, &sdp->sd_flags)) {
fs_err(sdp, "dlm lockspace ops disallow jid preset\n");
error = -EINVAL;
goto fail_release;
}
/*
* control_mount() uses control_lock to determine first mounter,
* and for later mounts, waits for any recoveries to be cleared.
*/
error = control_mount(sdp);
if (error) {
fs_err(sdp, "mount control error %d\n", error);
goto fail_release;
}
ls->ls_first = !!test_bit(DFL_FIRST_MOUNT, &ls->ls_recover_flags);
clear_bit(SDF_NOJOURNALID, &sdp->sd_flags);
smp_mb__after_clear_bit();
wake_up_bit(&sdp->sd_flags, SDF_NOJOURNALID);
return 0;
fail_release:
dlm_release_lockspace(ls->ls_dlm, 2);
fail_free:
free_recover_size(ls);
fail:
return error;
}
static void gdlm_first_done(struct gfs2_sbd *sdp)
{
struct lm_lockstruct *ls = &sdp->sd_lockstruct;
int error;
if (test_bit(DFL_NO_DLM_OPS, &ls->ls_recover_flags))
return;
error = control_first_done(sdp);
if (error)
fs_err(sdp, "mount first_done error %d\n", error);
}
static void gdlm_unmount(struct gfs2_sbd *sdp)
{
struct lm_lockstruct *ls = &sdp->sd_lockstruct;
if (test_bit(DFL_NO_DLM_OPS, &ls->ls_recover_flags))
goto release;
/* wait for gfs2_control_wq to be done with this mount */
spin_lock(&ls->ls_recover_spin);
set_bit(DFL_UNMOUNT, &ls->ls_recover_flags);
spin_unlock(&ls->ls_recover_spin);
flush_delayed_work_sync(&sdp->sd_control_work);
/* mounted_lock and control_lock will be purged in dlm recovery */
release:
if (ls->ls_dlm) {
dlm_release_lockspace(ls->ls_dlm, 2);
ls->ls_dlm = NULL;
}
free_recover_size(ls);
}
static const match_table_t dlm_tokens = {
{ Opt_jid, "jid=%d"},
{ Opt_id, "id=%d"},
{ Opt_first, "first=%d"},
{ Opt_nodir, "nodir=%d"},
{ Opt_err, NULL },
};
const struct lm_lockops gfs2_dlm_ops = {
.lm_proto_name = "lock_dlm",
.lm_mount = gdlm_mount,
.lm_first_done = gdlm_first_done,
.lm_recovery_result = gdlm_recovery_result,
.lm_unmount = gdlm_unmount,
.lm_put_lock = gdlm_put_lock,
.lm_lock = gdlm_lock,
.lm_cancel = gdlm_cancel,
.lm_tokens = &dlm_tokens,
};