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lock_dlm.c
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lock_dlm.c
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// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved.
* Copyright 2004-2011 Red Hat, Inc.
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#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 <linux/sched/signal.h>
#include "incore.h"
#include "glock.h"
#include "glops.h"
#include "recovery.h"
#include "util.h"
#include "sys.h"
#include "trace_gfs2.h"
/**
* 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 variance estimate is a bit
* more complicated. We subtract the current variance estimate from
* the abs value of the @delta and add 1/4 of that to the running
* total. That's equivalent to 3/4 of the current variance
* estimate plus 1/4 of the abs of @delta.
*
* 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] += (s64)(abs(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_name.ln_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_name.ln_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) && gl->gl_lksb.sb_lvbptr)
memset(gl->gl_lksb.sb_lvbptr, 0, GDLM_LVB_SIZE);
switch (gl->gl_lksb.sb_status) {
case -DLM_EUNLOCK: /* Unlocked, so glock can be freed */
if (gl->gl_ops->go_free)
gl->gl_ops->go_free(gl);
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:
fs_err(gl->gl_name.ln_sbd, "unknown bast mode %d\n", mode);
BUG();
}
}
/* convert gfs lock-state to dlm lock-mode */
static int make_mode(struct gfs2_sbd *sdp, 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;
}
fs_err(sdp, "unknown LM state %d\n", lmstate);
BUG();
return -1;
}
static u32 make_flags(struct gfs2_glock *gl, const unsigned int gfs_flags,
const int req)
{
u32 lkf = 0;
if (gl->gl_lksb.sb_lvbptr)
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 (gl->gl_lksb.sb_lkid != 0) {
lkf |= DLM_LKF_CONVERT;
if (test_bit(GLF_BLOCKING, &gl->gl_flags))
lkf |= DLM_LKF_QUECVT;
}
return lkf;
}
static void gfs2_reverse_hex(char *c, u64 value)
{
*c = '0';
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_name.ln_sbd->sd_lockstruct;
int req;
u32 lkf;
char strname[GDLM_STRNAME_BYTES] = "";
req = make_mode(gl->gl_name.ln_sbd, req_state);
lkf = make_flags(gl, 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_name.ln_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);
/* don't want to skip dlm_unlock writing the lvb when lock has one */
if (test_bit(SDF_SKIP_DLM_UNLOCK, &sdp->sd_flags) &&
!gl->gl_lksb.sb_lvbptr) {
gfs2_glock_free(gl);
return;
}
error = dlm_unlock(ls->ls_dlm, gl->gl_lksb.sb_lkid, DLM_LKF_VALBLK,
NULL, gl);
if (error) {
fs_err(sdp, "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_name.ln_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
*
* 0. gfs2 checks for another cluster node withdraw, needing journal replay
* 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)
{
__le32 gen;
memcpy(lvb_bits, ls->ls_control_lvb, GDLM_LVB_SIZE);
memcpy(&gen, lvb_bits, sizeof(__le32));
*lvb_gen = le32_to_cpu(gen);
}
static void control_lvb_write(struct lm_lockstruct *ls, uint32_t lvb_gen,
char *lvb_bits)
{
__le32 gen;
memcpy(ls->ls_control_lvb, lvb_bits, GDLM_LVB_SIZE);
gen = cpu_to_le32(lvb_gen);
memcpy(ls->ls_control_lvb, &gen, sizeof(__le32));
}
static int all_jid_bits_clear(char *lvb)
{
return !memchr_inv(lvb + JID_BITMAP_OFFSET, 0,
GDLM_LVB_SIZE - JID_BITMAP_OFFSET);
}
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");
}
/**
* remote_withdraw - react to a node withdrawing from the file system
* @sdp: The superblock
*/
static void remote_withdraw(struct gfs2_sbd *sdp)
{
struct gfs2_jdesc *jd;
int ret = 0, count = 0;
list_for_each_entry(jd, &sdp->sd_jindex_list, jd_list) {
if (jd->jd_jid == sdp->sd_lockstruct.ls_jid)
continue;
ret = gfs2_recover_journal(jd, true);
if (ret)
break;
count++;
}
/* Now drop the additional reference we acquired */
fs_err(sdp, "Journals checked: %d, ret = %d.\n", count, ret);
}
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;
uint32_t block_gen, start_gen, lvb_gen, flags;
int recover_set = 0;
int write_lvb = 0;
int recover_size;
int i, error;
/* First check for other nodes that may have done a withdraw. */
if (test_bit(SDF_REMOTE_WITHDRAW, &sdp->sd_flags)) {
remote_withdraw(sdp);
clear_bit(SDF_REMOTE_WITHDRAW, &sdp->sd_flags);
return;
}
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, ls->ls_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, ls->ls_lvb_bits + JID_BITMAP_OFFSET))
continue;
__clear_bit_le(i, ls->ls_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, ls->ls_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, ls->ls_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, ls->ls_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;
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;
}
/**
* If we're a spectator, we don't want to take the lock in EX because
* we cannot do the first-mount responsibility it implies: recovery.
*/
if (sdp->sd_args.ar_spectator)
goto locks_done;
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, ls->ls_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(ls->ls_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 */
if (sdp->sd_args.ar_spectator) {
fs_info(sdp, "Recovery is required. Waiting for a "
"non-spectator to mount.\n");
msleep_interruptible(1000);
} else {
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 control_first_done(struct gfs2_sbd *sdp)
{
struct lm_lockstruct *ls = &sdp->sd_lockstruct;
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;
}