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alistair23-linux/fs/gfs2/recovery.c
NeilBrown 743162013d sched: Remove proliferation of wait_on_bit() action functions 
The current "wait_on_bit" interface requires an 'action'
function to be provided which does the actual waiting.
There are over 20 such functions, many of them identical.
Most cases can be satisfied by one of just two functions, one
which uses io_schedule() and one which just uses schedule().

So:
 Rename wait_on_bit and        wait_on_bit_lock to
        wait_on_bit_action and wait_on_bit_lock_action
 to make it explicit that they need an action function.

 Introduce new wait_on_bit{,_lock} and wait_on_bit{,_lock}_io
 which are *not* given an action function but implicitly use
 a standard one.
 The decision to error-out if a signal is pending is now made
 based on the 'mode' argument rather than being encoded in the action
 function.

 All instances of the old wait_on_bit and wait_on_bit_lock which
 can use the new version have been changed accordingly and their
 action functions have been discarded.
 wait_on_bit{_lock} does not return any specific error code in the
 event of a signal so the caller must check for non-zero and
 interpolate their own error code as appropriate.

The wait_on_bit() call in __fscache_wait_on_invalidate() was
ambiguous as it specified TASK_UNINTERRUPTIBLE but used
fscache_wait_bit_interruptible as an action function.
David Howells confirms this should be uniformly
"uninterruptible"

The main remaining user of wait_on_bit{,_lock}_action is NFS
which needs to use a freezer-aware schedule() call.

A comment in fs/gfs2/glock.c notes that having multiple 'action'
functions is useful as they display differently in the 'wchan'
field of 'ps'. (and /proc/$PID/wchan).
As the new bit_wait{,_io} functions are tagged "__sched", they
will not show up at all, but something higher in the stack.  So
the distinction will still be visible, only with different
function names (gds2_glock_wait versus gfs2_glock_dq_wait in the
gfs2/glock.c case).

Since first version of this patch (against 3.15) two new action
functions appeared, on in NFS and one in CIFS.  CIFS also now
uses an action function that makes the same freezer aware
schedule call as NFS.

Signed-off-by: NeilBrown <neilb@suse.de>
Acked-by: David Howells <dhowells@redhat.com> (fscache, keys)
Acked-by: Steven Whitehouse <swhiteho@redhat.com> (gfs2)
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Steve French <sfrench@samba.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Link: http://lkml.kernel.org/r/20140707051603.28027.72349.stgit@notabene.brown
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2014-07-16 15:10:39 +02:00

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/*
* Copyright (C) Sistina Software, Inc. 1997-2003 All rights reserved.
* Copyright (C) 2004-2006 Red Hat, Inc. All rights reserved.
*
* 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/module.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/completion.h>
#include <linux/buffer_head.h>
#include <linux/gfs2_ondisk.h>
#include <linux/crc32.h>
#include "gfs2.h"
#include "incore.h"
#include "bmap.h"
#include "glock.h"
#include "glops.h"
#include "lops.h"
#include "meta_io.h"
#include "recovery.h"
#include "super.h"
#include "util.h"
#include "dir.h"
struct workqueue_struct *gfs_recovery_wq;
int gfs2_replay_read_block(struct gfs2_jdesc *jd, unsigned int blk,
struct buffer_head **bh)
{
struct gfs2_inode *ip = GFS2_I(jd->jd_inode);
struct gfs2_glock *gl = ip->i_gl;
int new = 0;
u64 dblock;
u32 extlen;
int error;
error = gfs2_extent_map(&ip->i_inode, blk, &new, &dblock, &extlen);
if (error)
return error;
if (!dblock) {
gfs2_consist_inode(ip);
return -EIO;
}
*bh = gfs2_meta_ra(gl, dblock, extlen);
return error;
}
int gfs2_revoke_add(struct gfs2_jdesc *jd, u64 blkno, unsigned int where)
{
struct list_head *head = &jd->jd_revoke_list;
struct gfs2_revoke_replay *rr;
int found = 0;
list_for_each_entry(rr, head, rr_list) {
if (rr->rr_blkno == blkno) {
found = 1;
break;
}
}
if (found) {
rr->rr_where = where;
return 0;
}
rr = kmalloc(sizeof(struct gfs2_revoke_replay), GFP_NOFS);
if (!rr)
return -ENOMEM;
rr->rr_blkno = blkno;
rr->rr_where = where;
list_add(&rr->rr_list, head);
return 1;
}
int gfs2_revoke_check(struct gfs2_jdesc *jd, u64 blkno, unsigned int where)
{
struct gfs2_revoke_replay *rr;
int wrap, a, b, revoke;
int found = 0;
list_for_each_entry(rr, &jd->jd_revoke_list, rr_list) {
if (rr->rr_blkno == blkno) {
found = 1;
break;
}
}
if (!found)
return 0;
wrap = (rr->rr_where < jd->jd_replay_tail);
a = (jd->jd_replay_tail < where);
b = (where < rr->rr_where);
revoke = (wrap) ? (a || b) : (a && b);
return revoke;
}
void gfs2_revoke_clean(struct gfs2_jdesc *jd)
{
struct list_head *head = &jd->jd_revoke_list;
struct gfs2_revoke_replay *rr;
while (!list_empty(head)) {
rr = list_entry(head->next, struct gfs2_revoke_replay, rr_list);
list_del(&rr->rr_list);
kfree(rr);
}
}
static int gfs2_log_header_in(struct gfs2_log_header_host *lh, const void *buf)
{
const struct gfs2_log_header *str = buf;
if (str->lh_header.mh_magic != cpu_to_be32(GFS2_MAGIC) ||
str->lh_header.mh_type != cpu_to_be32(GFS2_METATYPE_LH))
return 1;
lh->lh_sequence = be64_to_cpu(str->lh_sequence);
lh->lh_flags = be32_to_cpu(str->lh_flags);
lh->lh_tail = be32_to_cpu(str->lh_tail);
lh->lh_blkno = be32_to_cpu(str->lh_blkno);
lh->lh_hash = be32_to_cpu(str->lh_hash);
return 0;
}
/**
* get_log_header - read the log header for a given segment
* @jd: the journal
* @blk: the block to look at
* @lh: the log header to return
*
* Read the log header for a given segement in a given journal. Do a few
* sanity checks on it.
*
* Returns: 0 on success,
* 1 if the header was invalid or incomplete,
* errno on error
*/
static int get_log_header(struct gfs2_jdesc *jd, unsigned int blk,
struct gfs2_log_header_host *head)
{
struct buffer_head *bh;
struct gfs2_log_header_host uninitialized_var(lh);
const u32 nothing = 0;
u32 hash;
int error;
error = gfs2_replay_read_block(jd, blk, &bh);
if (error)
return error;
hash = crc32_le((u32)~0, bh->b_data, sizeof(struct gfs2_log_header) -
sizeof(u32));
hash = crc32_le(hash, (unsigned char const *)&nothing, sizeof(nothing));
hash ^= (u32)~0;
error = gfs2_log_header_in(&lh, bh->b_data);
brelse(bh);
if (error || lh.lh_blkno != blk || lh.lh_hash != hash)
return 1;
*head = lh;
return 0;
}
/**
* find_good_lh - find a good log header
* @jd: the journal
* @blk: the segment to start searching from
* @lh: the log header to fill in
* @forward: if true search forward in the log, else search backward
*
* Call get_log_header() to get a log header for a segment, but if the
* segment is bad, either scan forward or backward until we find a good one.
*
* Returns: errno
*/
static int find_good_lh(struct gfs2_jdesc *jd, unsigned int *blk,
struct gfs2_log_header_host *head)
{
unsigned int orig_blk = *blk;
int error;
for (;;) {
error = get_log_header(jd, *blk, head);
if (error <= 0)
return error;
if (++*blk == jd->jd_blocks)
*blk = 0;
if (*blk == orig_blk) {
gfs2_consist_inode(GFS2_I(jd->jd_inode));
return -EIO;
}
}
}
/**
* jhead_scan - make sure we've found the head of the log
* @jd: the journal
* @head: this is filled in with the log descriptor of the head
*
* At this point, seg and lh should be either the head of the log or just
* before. Scan forward until we find the head.
*
* Returns: errno
*/
static int jhead_scan(struct gfs2_jdesc *jd, struct gfs2_log_header_host *head)
{
unsigned int blk = head->lh_blkno;
struct gfs2_log_header_host lh;
int error;
for (;;) {
if (++blk == jd->jd_blocks)
blk = 0;
error = get_log_header(jd, blk, &lh);
if (error < 0)
return error;
if (error == 1)
continue;
if (lh.lh_sequence == head->lh_sequence) {
gfs2_consist_inode(GFS2_I(jd->jd_inode));
return -EIO;
}
if (lh.lh_sequence < head->lh_sequence)
break;
*head = lh;
}
return 0;
}
/**
* gfs2_find_jhead - find the head of a log
* @jd: the journal
* @head: the log descriptor for the head of the log is returned here
*
* Do a binary search of a journal and find the valid log entry with the
* highest sequence number. (i.e. the log head)
*
* Returns: errno
*/
int gfs2_find_jhead(struct gfs2_jdesc *jd, struct gfs2_log_header_host *head)
{
struct gfs2_log_header_host lh_1, lh_m;
u32 blk_1, blk_2, blk_m;
int error;
blk_1 = 0;
blk_2 = jd->jd_blocks - 1;
for (;;) {
blk_m = (blk_1 + blk_2) / 2;
error = find_good_lh(jd, &blk_1, &lh_1);
if (error)
return error;
error = find_good_lh(jd, &blk_m, &lh_m);
if (error)
return error;
if (blk_1 == blk_m || blk_m == blk_2)
break;
if (lh_1.lh_sequence <= lh_m.lh_sequence)
blk_1 = blk_m;
else
blk_2 = blk_m;
}
error = jhead_scan(jd, &lh_1);
if (error)
return error;
*head = lh_1;
return error;
}
/**
* foreach_descriptor - go through the active part of the log
* @jd: the journal
* @start: the first log header in the active region
* @end: the last log header (don't process the contents of this entry))
*
* Call a given function once for every log descriptor in the active
* portion of the log.
*
* Returns: errno
*/
static int foreach_descriptor(struct gfs2_jdesc *jd, unsigned int start,
unsigned int end, int pass)
{
struct gfs2_sbd *sdp = GFS2_SB(jd->jd_inode);
struct buffer_head *bh;
struct gfs2_log_descriptor *ld;
int error = 0;
u32 length;
__be64 *ptr;
unsigned int offset = sizeof(struct gfs2_log_descriptor);
offset += sizeof(__be64) - 1;
offset &= ~(sizeof(__be64) - 1);
while (start != end) {
error = gfs2_replay_read_block(jd, start, &bh);
if (error)
return error;
if (gfs2_meta_check(sdp, bh)) {
brelse(bh);
return -EIO;
}
ld = (struct gfs2_log_descriptor *)bh->b_data;
length = be32_to_cpu(ld->ld_length);
if (be32_to_cpu(ld->ld_header.mh_type) == GFS2_METATYPE_LH) {
struct gfs2_log_header_host lh;
error = get_log_header(jd, start, &lh);
if (!error) {
gfs2_replay_incr_blk(sdp, &start);
brelse(bh);
continue;
}
if (error == 1) {
gfs2_consist_inode(GFS2_I(jd->jd_inode));
error = -EIO;
}
brelse(bh);
return error;
} else if (gfs2_metatype_check(sdp, bh, GFS2_METATYPE_LD)) {
brelse(bh);
return -EIO;
}
ptr = (__be64 *)(bh->b_data + offset);
error = lops_scan_elements(jd, start, ld, ptr, pass);
if (error) {
brelse(bh);
return error;
}
while (length--)
gfs2_replay_incr_blk(sdp, &start);
brelse(bh);
}
return 0;
}
/**
* clean_journal - mark a dirty journal as being clean
* @sdp: the filesystem
* @jd: the journal
* @gl: the journal's glock
* @head: the head journal to start from
*
* Returns: errno
*/
static int clean_journal(struct gfs2_jdesc *jd, struct gfs2_log_header_host *head)
{
struct gfs2_inode *ip = GFS2_I(jd->jd_inode);
struct gfs2_sbd *sdp = GFS2_SB(jd->jd_inode);
unsigned int lblock;
struct gfs2_log_header *lh;
u32 hash;
struct buffer_head *bh;
int error;
struct buffer_head bh_map = { .b_state = 0, .b_blocknr = 0 };
lblock = head->lh_blkno;
gfs2_replay_incr_blk(sdp, &lblock);
bh_map.b_size = 1 << ip->i_inode.i_blkbits;
error = gfs2_block_map(&ip->i_inode, lblock, &bh_map, 0);
if (error)
return error;
if (!bh_map.b_blocknr) {
gfs2_consist_inode(ip);
return -EIO;
}
bh = sb_getblk(sdp->sd_vfs, bh_map.b_blocknr);
lock_buffer(bh);
memset(bh->b_data, 0, bh->b_size);
set_buffer_uptodate(bh);
clear_buffer_dirty(bh);
unlock_buffer(bh);
lh = (struct gfs2_log_header *)bh->b_data;
memset(lh, 0, sizeof(struct gfs2_log_header));
lh->lh_header.mh_magic = cpu_to_be32(GFS2_MAGIC);
lh->lh_header.mh_type = cpu_to_be32(GFS2_METATYPE_LH);
lh->lh_header.__pad0 = cpu_to_be64(0);
lh->lh_header.mh_format = cpu_to_be32(GFS2_FORMAT_LH);
lh->lh_header.mh_jid = cpu_to_be32(sdp->sd_jdesc->jd_jid);
lh->lh_sequence = cpu_to_be64(head->lh_sequence + 1);
lh->lh_flags = cpu_to_be32(GFS2_LOG_HEAD_UNMOUNT);
lh->lh_blkno = cpu_to_be32(lblock);
hash = gfs2_disk_hash((const char *)lh, sizeof(struct gfs2_log_header));
lh->lh_hash = cpu_to_be32(hash);
set_buffer_dirty(bh);
if (sync_dirty_buffer(bh))
gfs2_io_error_bh(sdp, bh);
brelse(bh);
return error;
}
static void gfs2_recovery_done(struct gfs2_sbd *sdp, unsigned int jid,
unsigned int message)
{
char env_jid[20];
char env_status[20];
char *envp[] = { env_jid, env_status, NULL };
struct lm_lockstruct *ls = &sdp->sd_lockstruct;
ls->ls_recover_jid_done = jid;
ls->ls_recover_jid_status = message;
sprintf(env_jid, "JID=%d", jid);
sprintf(env_status, "RECOVERY=%s",
message == LM_RD_SUCCESS ? "Done" : "Failed");
kobject_uevent_env(&sdp->sd_kobj, KOBJ_CHANGE, envp);
if (sdp->sd_lockstruct.ls_ops->lm_recovery_result)
sdp->sd_lockstruct.ls_ops->lm_recovery_result(sdp, jid, message);
}
void gfs2_recover_func(struct work_struct *work)
{
struct gfs2_jdesc *jd = container_of(work, struct gfs2_jdesc, jd_work);
struct gfs2_inode *ip = GFS2_I(jd->jd_inode);
struct gfs2_sbd *sdp = GFS2_SB(jd->jd_inode);
struct gfs2_log_header_host head;
struct gfs2_holder j_gh, ji_gh, thaw_gh;
unsigned long t;
int ro = 0;
unsigned int pass;
int error;
int jlocked = 0;
if (sdp->sd_args.ar_spectator ||
(jd->jd_jid != sdp->sd_lockstruct.ls_jid)) {
fs_info(sdp, "jid=%u: Trying to acquire journal lock...\n",
jd->jd_jid);
jlocked = 1;
/* Acquire the journal lock so we can do recovery */
error = gfs2_glock_nq_num(sdp, jd->jd_jid, &gfs2_journal_glops,
LM_ST_EXCLUSIVE,
LM_FLAG_NOEXP | LM_FLAG_TRY | GL_NOCACHE,
&j_gh);
switch (error) {
case 0:
break;
case GLR_TRYFAILED:
fs_info(sdp, "jid=%u: Busy\n", jd->jd_jid);
error = 0;
default:
goto fail;
};
error = gfs2_glock_nq_init(ip->i_gl, LM_ST_SHARED,
LM_FLAG_NOEXP | GL_NOCACHE, &ji_gh);
if (error)
goto fail_gunlock_j;
} else {
fs_info(sdp, "jid=%u, already locked for use\n", jd->jd_jid);
}
fs_info(sdp, "jid=%u: Looking at journal...\n", jd->jd_jid);
error = gfs2_jdesc_check(jd);
if (error)
goto fail_gunlock_ji;
error = gfs2_find_jhead(jd, &head);
if (error)
goto fail_gunlock_ji;
if (!(head.lh_flags & GFS2_LOG_HEAD_UNMOUNT)) {
fs_info(sdp, "jid=%u: Acquiring the transaction lock...\n",
jd->jd_jid);
t = jiffies;
/* Acquire a shared hold on the freeze lock */
error = gfs2_glock_nq_init(sdp->sd_freeze_gl, LM_ST_SHARED,
LM_FLAG_NOEXP | LM_FLAG_PRIORITY,
&thaw_gh);
if (error)
goto fail_gunlock_ji;
if (test_bit(SDF_RORECOVERY, &sdp->sd_flags)) {
ro = 1;
} else if (test_bit(SDF_JOURNAL_CHECKED, &sdp->sd_flags)) {
if (!test_bit(SDF_JOURNAL_LIVE, &sdp->sd_flags))
ro = 1;
} else {
if (sdp->sd_vfs->s_flags & MS_RDONLY) {
/* check if device itself is read-only */
ro = bdev_read_only(sdp->sd_vfs->s_bdev);
if (!ro) {
fs_info(sdp, "recovery required on "
"read-only filesystem.\n");
fs_info(sdp, "write access will be "
"enabled during recovery.\n");
}
}
}
if (ro) {
fs_warn(sdp, "jid=%u: Can't replay: read-only block "
"device\n", jd->jd_jid);
error = -EROFS;
goto fail_gunlock_thaw;
}
fs_info(sdp, "jid=%u: Replaying journal...\n", jd->jd_jid);
for (pass = 0; pass < 2; pass++) {
lops_before_scan(jd, &head, pass);
error = foreach_descriptor(jd, head.lh_tail,
head.lh_blkno, pass);
lops_after_scan(jd, error, pass);
if (error)
goto fail_gunlock_thaw;
}
error = clean_journal(jd, &head);
if (error)
goto fail_gunlock_thaw;
gfs2_glock_dq_uninit(&thaw_gh);
t = DIV_ROUND_UP(jiffies - t, HZ);
fs_info(sdp, "jid=%u: Journal replayed in %lus\n",
jd->jd_jid, t);
}
gfs2_recovery_done(sdp, jd->jd_jid, LM_RD_SUCCESS);
if (jlocked) {
gfs2_glock_dq_uninit(&ji_gh);
gfs2_glock_dq_uninit(&j_gh);
}
fs_info(sdp, "jid=%u: Done\n", jd->jd_jid);
goto done;
fail_gunlock_thaw:
gfs2_glock_dq_uninit(&thaw_gh);
fail_gunlock_ji:
if (jlocked) {
gfs2_glock_dq_uninit(&ji_gh);
fail_gunlock_j:
gfs2_glock_dq_uninit(&j_gh);
}
fs_info(sdp, "jid=%u: %s\n", jd->jd_jid, (error) ? "Failed" : "Done");
fail:
jd->jd_recover_error = error;
gfs2_recovery_done(sdp, jd->jd_jid, LM_RD_GAVEUP);
done:
clear_bit(JDF_RECOVERY, &jd->jd_flags);
smp_mb__after_atomic();
wake_up_bit(&jd->jd_flags, JDF_RECOVERY);
}
int gfs2_recover_journal(struct gfs2_jdesc *jd, bool wait)
{
int rv;
if (test_and_set_bit(JDF_RECOVERY, &jd->jd_flags))
return -EBUSY;
/* we have JDF_RECOVERY, queue should always succeed */
rv = queue_work(gfs_recovery_wq, &jd->jd_work);
BUG_ON(!rv);
if (wait)
wait_on_bit(&jd->jd_flags, JDF_RECOVERY,
TASK_UNINTERRUPTIBLE);
return wait ? jd->jd_recover_error : 0;
}
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