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linux/fs/xfs/xfs_log.c
Dave Chinner b5203cd0a4 xfs: factor xlog_write 
xlog_write is a mess that takes a lot of effort to understand. It is
a mass of nested loops with 4 space indents to get it to fit in 80 columns
and lots of funky variables that aren't obvious what they mean or do.

Break it down into understandable chunks.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2010-05-19 09:58:09 -05:00

3751 lines
105 KiB
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/*
* Copyright (c) 2000-2005 Silicon Graphics, Inc.
* All Rights Reserved.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it would be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write the Free Software Foundation,
* Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "xfs.h"
#include "xfs_fs.h"
#include "xfs_types.h"
#include "xfs_bit.h"
#include "xfs_log.h"
#include "xfs_inum.h"
#include "xfs_trans.h"
#include "xfs_sb.h"
#include "xfs_ag.h"
#include "xfs_dir2.h"
#include "xfs_dmapi.h"
#include "xfs_mount.h"
#include "xfs_error.h"
#include "xfs_log_priv.h"
#include "xfs_buf_item.h"
#include "xfs_bmap_btree.h"
#include "xfs_alloc_btree.h"
#include "xfs_ialloc_btree.h"
#include "xfs_log_recover.h"
#include "xfs_trans_priv.h"
#include "xfs_dir2_sf.h"
#include "xfs_attr_sf.h"
#include "xfs_dinode.h"
#include "xfs_inode.h"
#include "xfs_rw.h"
#include "xfs_trace.h"
kmem_zone_t *xfs_log_ticket_zone;
#define xlog_write_adv_cnt(ptr, len, off, bytes) \
{ (ptr) += (bytes); \
(len) -= (bytes); \
(off) += (bytes);}
/* Local miscellaneous function prototypes */
STATIC int xlog_commit_record(xfs_mount_t *mp, xlog_ticket_t *ticket,
xlog_in_core_t **, xfs_lsn_t *);
STATIC xlog_t * xlog_alloc_log(xfs_mount_t *mp,
xfs_buftarg_t *log_target,
xfs_daddr_t blk_offset,
int num_bblks);
STATIC int xlog_space_left(xlog_t *log, int cycle, int bytes);
STATIC int xlog_sync(xlog_t *log, xlog_in_core_t *iclog);
STATIC void xlog_dealloc_log(xlog_t *log);
STATIC int xlog_write(xfs_mount_t *mp, xfs_log_iovec_t region[],
int nentries, struct xlog_ticket *tic,
xfs_lsn_t *start_lsn,
xlog_in_core_t **commit_iclog,
uint flags);
/* local state machine functions */
STATIC void xlog_state_done_syncing(xlog_in_core_t *iclog, int);
STATIC void xlog_state_do_callback(xlog_t *log,int aborted, xlog_in_core_t *iclog);
STATIC int xlog_state_get_iclog_space(xlog_t *log,
int len,
xlog_in_core_t **iclog,
xlog_ticket_t *ticket,
int *continued_write,
int *logoffsetp);
STATIC int xlog_state_release_iclog(xlog_t *log,
xlog_in_core_t *iclog);
STATIC void xlog_state_switch_iclogs(xlog_t *log,
xlog_in_core_t *iclog,
int eventual_size);
STATIC void xlog_state_want_sync(xlog_t *log, xlog_in_core_t *iclog);
/* local functions to manipulate grant head */
STATIC int xlog_grant_log_space(xlog_t *log,
xlog_ticket_t *xtic);
STATIC void xlog_grant_push_ail(xfs_mount_t *mp,
int need_bytes);
STATIC void xlog_regrant_reserve_log_space(xlog_t *log,
xlog_ticket_t *ticket);
STATIC int xlog_regrant_write_log_space(xlog_t *log,
xlog_ticket_t *ticket);
STATIC void xlog_ungrant_log_space(xlog_t *log,
xlog_ticket_t *ticket);
/* local ticket functions */
STATIC xlog_ticket_t *xlog_ticket_alloc(xlog_t *log,
int unit_bytes,
int count,
char clientid,
uint flags);
#if defined(DEBUG)
STATIC void xlog_verify_dest_ptr(xlog_t *log, __psint_t ptr);
STATIC void xlog_verify_grant_head(xlog_t *log, int equals);
STATIC void xlog_verify_iclog(xlog_t *log, xlog_in_core_t *iclog,
int count, boolean_t syncing);
STATIC void xlog_verify_tail_lsn(xlog_t *log, xlog_in_core_t *iclog,
xfs_lsn_t tail_lsn);
#else
#define xlog_verify_dest_ptr(a,b)
#define xlog_verify_grant_head(a,b)
#define xlog_verify_iclog(a,b,c,d)
#define xlog_verify_tail_lsn(a,b,c)
#endif
STATIC int xlog_iclogs_empty(xlog_t *log);
static void
xlog_ins_ticketq(struct xlog_ticket **qp, struct xlog_ticket *tic)
{
if (*qp) {
tic->t_next = (*qp);
tic->t_prev = (*qp)->t_prev;
(*qp)->t_prev->t_next = tic;
(*qp)->t_prev = tic;
} else {
tic->t_prev = tic->t_next = tic;
*qp = tic;
}
tic->t_flags |= XLOG_TIC_IN_Q;
}
static void
xlog_del_ticketq(struct xlog_ticket **qp, struct xlog_ticket *tic)
{
if (tic == tic->t_next) {
*qp = NULL;
} else {
*qp = tic->t_next;
tic->t_next->t_prev = tic->t_prev;
tic->t_prev->t_next = tic->t_next;
}
tic->t_next = tic->t_prev = NULL;
tic->t_flags &= ~XLOG_TIC_IN_Q;
}
static void
xlog_grant_sub_space(struct log *log, int bytes)
{
log->l_grant_write_bytes -= bytes;
if (log->l_grant_write_bytes < 0) {
log->l_grant_write_bytes += log->l_logsize;
log->l_grant_write_cycle--;
}
log->l_grant_reserve_bytes -= bytes;
if ((log)->l_grant_reserve_bytes < 0) {
log->l_grant_reserve_bytes += log->l_logsize;
log->l_grant_reserve_cycle--;
}
}
static void
xlog_grant_add_space_write(struct log *log, int bytes)
{
int tmp = log->l_logsize - log->l_grant_write_bytes;
if (tmp > bytes)
log->l_grant_write_bytes += bytes;
else {
log->l_grant_write_cycle++;
log->l_grant_write_bytes = bytes - tmp;
}
}
static void
xlog_grant_add_space_reserve(struct log *log, int bytes)
{
int tmp = log->l_logsize - log->l_grant_reserve_bytes;
if (tmp > bytes)
log->l_grant_reserve_bytes += bytes;
else {
log->l_grant_reserve_cycle++;
log->l_grant_reserve_bytes = bytes - tmp;
}
}
static inline void
xlog_grant_add_space(struct log *log, int bytes)
{
xlog_grant_add_space_write(log, bytes);
xlog_grant_add_space_reserve(log, bytes);
}
static void
xlog_tic_reset_res(xlog_ticket_t *tic)
{
tic->t_res_num = 0;
tic->t_res_arr_sum = 0;
tic->t_res_num_ophdrs = 0;
}
static void
xlog_tic_add_region(xlog_ticket_t *tic, uint len, uint type)
{
if (tic->t_res_num == XLOG_TIC_LEN_MAX) {
/* add to overflow and start again */
tic->t_res_o_flow += tic->t_res_arr_sum;
tic->t_res_num = 0;
tic->t_res_arr_sum = 0;
}
tic->t_res_arr[tic->t_res_num].r_len = len;
tic->t_res_arr[tic->t_res_num].r_type = type;
tic->t_res_arr_sum += len;
tic->t_res_num++;
}
/*
* NOTES:
*
* 1. currblock field gets updated at startup and after in-core logs
* marked as with WANT_SYNC.
*/
/*
* This routine is called when a user of a log manager ticket is done with
* the reservation. If the ticket was ever used, then a commit record for
* the associated transaction is written out as a log operation header with
* no data. The flag XLOG_TIC_INITED is set when the first write occurs with
* a given ticket. If the ticket was one with a permanent reservation, then
* a few operations are done differently. Permanent reservation tickets by
* default don't release the reservation. They just commit the current
* transaction with the belief that the reservation is still needed. A flag
* must be passed in before permanent reservations are actually released.
* When these type of tickets are not released, they need to be set into
* the inited state again. By doing this, a start record will be written
* out when the next write occurs.
*/
xfs_lsn_t
xfs_log_done(
struct xfs_mount *mp,
struct xlog_ticket *ticket,
struct xlog_in_core **iclog,
uint flags)
{
struct log *log = mp->m_log;
xfs_lsn_t lsn = 0;
if (XLOG_FORCED_SHUTDOWN(log) ||
/*
* If nothing was ever written, don't write out commit record.
* If we get an error, just continue and give back the log ticket.
*/
(((ticket->t_flags & XLOG_TIC_INITED) == 0) &&
(xlog_commit_record(mp, ticket, iclog, &lsn)))) {
lsn = (xfs_lsn_t) -1;
if (ticket->t_flags & XLOG_TIC_PERM_RESERV) {
flags |= XFS_LOG_REL_PERM_RESERV;
}
}
if ((ticket->t_flags & XLOG_TIC_PERM_RESERV) == 0 ||
(flags & XFS_LOG_REL_PERM_RESERV)) {
trace_xfs_log_done_nonperm(log, ticket);
/*
* Release ticket if not permanent reservation or a specific
* request has been made to release a permanent reservation.
*/
xlog_ungrant_log_space(log, ticket);
xfs_log_ticket_put(ticket);
} else {
trace_xfs_log_done_perm(log, ticket);
xlog_regrant_reserve_log_space(log, ticket);
/* If this ticket was a permanent reservation and we aren't
* trying to release it, reset the inited flags; so next time
* we write, a start record will be written out.
*/
ticket->t_flags |= XLOG_TIC_INITED;
}
return lsn;
}
/*
* Attaches a new iclog I/O completion callback routine during
* transaction commit. If the log is in error state, a non-zero
* return code is handed back and the caller is responsible for
* executing the callback at an appropriate time.
*/
int
xfs_log_notify(
struct xfs_mount *mp,
struct xlog_in_core *iclog,
xfs_log_callback_t *cb)
{
int abortflg;
spin_lock(&iclog->ic_callback_lock);
abortflg = (iclog->ic_state & XLOG_STATE_IOERROR);
if (!abortflg) {
ASSERT_ALWAYS((iclog->ic_state == XLOG_STATE_ACTIVE) ||
(iclog->ic_state == XLOG_STATE_WANT_SYNC));
cb->cb_next = NULL;
*(iclog->ic_callback_tail) = cb;
iclog->ic_callback_tail = &(cb->cb_next);
}
spin_unlock(&iclog->ic_callback_lock);
return abortflg;
}
int
xfs_log_release_iclog(
struct xfs_mount *mp,
struct xlog_in_core *iclog)
{
if (xlog_state_release_iclog(mp->m_log, iclog)) {
xfs_force_shutdown(mp, SHUTDOWN_LOG_IO_ERROR);
return EIO;
}
return 0;
}
/*
* 1. Reserve an amount of on-disk log space and return a ticket corresponding
* to the reservation.
* 2. Potentially, push buffers at tail of log to disk.
*
* Each reservation is going to reserve extra space for a log record header.
* When writes happen to the on-disk log, we don't subtract the length of the
* log record header from any reservation. By wasting space in each
* reservation, we prevent over allocation problems.
*/
int
xfs_log_reserve(
struct xfs_mount *mp,
int unit_bytes,
int cnt,
struct xlog_ticket **ticket,
__uint8_t client,
uint flags,
uint t_type)
{
struct log *log = mp->m_log;
struct xlog_ticket *internal_ticket;
int retval = 0;
ASSERT(client == XFS_TRANSACTION || client == XFS_LOG);
ASSERT((flags & XFS_LOG_NOSLEEP) == 0);
if (XLOG_FORCED_SHUTDOWN(log))
return XFS_ERROR(EIO);
XFS_STATS_INC(xs_try_logspace);
if (*ticket != NULL) {
ASSERT(flags & XFS_LOG_PERM_RESERV);
internal_ticket = *ticket;
trace_xfs_log_reserve(log, internal_ticket);
xlog_grant_push_ail(mp, internal_ticket->t_unit_res);
retval = xlog_regrant_write_log_space(log, internal_ticket);
} else {
/* may sleep if need to allocate more tickets */
internal_ticket = xlog_ticket_alloc(log, unit_bytes, cnt,
client, flags);
if (!internal_ticket)
return XFS_ERROR(ENOMEM);
internal_ticket->t_trans_type = t_type;
*ticket = internal_ticket;
trace_xfs_log_reserve(log, internal_ticket);
xlog_grant_push_ail(mp,
(internal_ticket->t_unit_res *
internal_ticket->t_cnt));
retval = xlog_grant_log_space(log, internal_ticket);
}
return retval;
} /* xfs_log_reserve */
/*
* Mount a log filesystem
*
* mp - ubiquitous xfs mount point structure
* log_target - buftarg of on-disk log device
* blk_offset - Start block # where block size is 512 bytes (BBSIZE)
* num_bblocks - Number of BBSIZE blocks in on-disk log
*
* Return error or zero.
*/
int
xfs_log_mount(
xfs_mount_t *mp,
xfs_buftarg_t *log_target,
xfs_daddr_t blk_offset,
int num_bblks)
{
int error;
if (!(mp->m_flags & XFS_MOUNT_NORECOVERY))
cmn_err(CE_NOTE, "XFS mounting filesystem %s", mp->m_fsname);
else {
cmn_err(CE_NOTE,
"!Mounting filesystem \"%s\" in no-recovery mode. Filesystem will be inconsistent.",
mp->m_fsname);
ASSERT(mp->m_flags & XFS_MOUNT_RDONLY);
}
mp->m_log = xlog_alloc_log(mp, log_target, blk_offset, num_bblks);
if (IS_ERR(mp->m_log)) {
error = -PTR_ERR(mp->m_log);
goto out;
}
/*
* Initialize the AIL now we have a log.
*/
error = xfs_trans_ail_init(mp);
if (error) {
cmn_err(CE_WARN, "XFS: AIL initialisation failed: error %d", error);
goto out_free_log;
}
mp->m_log->l_ailp = mp->m_ail;
/*
* skip log recovery on a norecovery mount. pretend it all
* just worked.
*/
if (!(mp->m_flags & XFS_MOUNT_NORECOVERY)) {
int readonly = (mp->m_flags & XFS_MOUNT_RDONLY);
if (readonly)
mp->m_flags &= ~XFS_MOUNT_RDONLY;
error = xlog_recover(mp->m_log);
if (readonly)
mp->m_flags |= XFS_MOUNT_RDONLY;
if (error) {
cmn_err(CE_WARN, "XFS: log mount/recovery failed: error %d", error);
goto out_destroy_ail;
}
}
/* Normal transactions can now occur */
mp->m_log->l_flags &= ~XLOG_ACTIVE_RECOVERY;
return 0;
out_destroy_ail:
xfs_trans_ail_destroy(mp);
out_free_log:
xlog_dealloc_log(mp->m_log);
out:
return error;
}
/*
* Finish the recovery of the file system. This is separate from
* the xfs_log_mount() call, because it depends on the code in
* xfs_mountfs() to read in the root and real-time bitmap inodes
* between calling xfs_log_mount() and here.
*
* mp - ubiquitous xfs mount point structure
*/
int
xfs_log_mount_finish(xfs_mount_t *mp)
{
int error;
if (!(mp->m_flags & XFS_MOUNT_NORECOVERY))
error = xlog_recover_finish(mp->m_log);
else {
error = 0;
ASSERT(mp->m_flags & XFS_MOUNT_RDONLY);
}
return error;
}
/*
* Final log writes as part of unmount.
*
* Mark the filesystem clean as unmount happens. Note that during relocation
* this routine needs to be executed as part of source-bag while the
* deallocation must not be done until source-end.
*/
/*
* Unmount record used to have a string "Unmount filesystem--" in the
* data section where the "Un" was really a magic number (XLOG_UNMOUNT_TYPE).
* We just write the magic number now since that particular field isn't
* currently architecture converted and "nUmount" is a bit foo.
* As far as I know, there weren't any dependencies on the old behaviour.
*/
int
xfs_log_unmount_write(xfs_mount_t *mp)
{
xlog_t *log = mp->m_log;
xlog_in_core_t *iclog;
#ifdef DEBUG
xlog_in_core_t *first_iclog;
#endif
xfs_log_iovec_t reg[1];
xlog_ticket_t *tic = NULL;
xfs_lsn_t lsn;
int error;
/* the data section must be 32 bit size aligned */
struct {
__uint16_t magic;
__uint16_t pad1;
__uint32_t pad2; /* may as well make it 64 bits */
} magic = { XLOG_UNMOUNT_TYPE, 0, 0 };
/*
* Don't write out unmount record on read-only mounts.
* Or, if we are doing a forced umount (typically because of IO errors).
*/
if (mp->m_flags & XFS_MOUNT_RDONLY)
return 0;
error = _xfs_log_force(mp, XFS_LOG_SYNC, NULL);
ASSERT(error || !(XLOG_FORCED_SHUTDOWN(log)));
#ifdef DEBUG
first_iclog = iclog = log->l_iclog;
do {
if (!(iclog->ic_state & XLOG_STATE_IOERROR)) {
ASSERT(iclog->ic_state & XLOG_STATE_ACTIVE);
ASSERT(iclog->ic_offset == 0);
}
iclog = iclog->ic_next;
} while (iclog != first_iclog);
#endif
if (! (XLOG_FORCED_SHUTDOWN(log))) {
reg[0].i_addr = (void*)&magic;
reg[0].i_len = sizeof(magic);
reg[0].i_type = XLOG_REG_TYPE_UNMOUNT;
error = xfs_log_reserve(mp, 600, 1, &tic,
XFS_LOG, 0, XLOG_UNMOUNT_REC_TYPE);
if (!error) {
/* remove inited flag */
((xlog_ticket_t *)tic)->t_flags = 0;
error = xlog_write(mp, reg, 1, tic, &lsn,
NULL, XLOG_UNMOUNT_TRANS);
/*
* At this point, we're umounting anyway,
* so there's no point in transitioning log state
* to IOERROR. Just continue...
*/
}
if (error) {
xfs_fs_cmn_err(CE_ALERT, mp,
"xfs_log_unmount: unmount record failed");
}
spin_lock(&log->l_icloglock);
iclog = log->l_iclog;
atomic_inc(&iclog->ic_refcnt);
xlog_state_want_sync(log, iclog);
spin_unlock(&log->l_icloglock);
error = xlog_state_release_iclog(log, iclog);
spin_lock(&log->l_icloglock);
if (!(iclog->ic_state == XLOG_STATE_ACTIVE ||
iclog->ic_state == XLOG_STATE_DIRTY)) {
if (!XLOG_FORCED_SHUTDOWN(log)) {
sv_wait(&iclog->ic_force_wait, PMEM,
&log->l_icloglock, s);
} else {
spin_unlock(&log->l_icloglock);
}
} else {
spin_unlock(&log->l_icloglock);
}
if (tic) {
trace_xfs_log_umount_write(log, tic);
xlog_ungrant_log_space(log, tic);
xfs_log_ticket_put(tic);
}
} else {
/*
* We're already in forced_shutdown mode, couldn't
* even attempt to write out the unmount transaction.
*
* Go through the motions of sync'ing and releasing
* the iclog, even though no I/O will actually happen,
* we need to wait for other log I/Os that may already
* be in progress. Do this as a separate section of
* code so we'll know if we ever get stuck here that
* we're in this odd situation of trying to unmount
* a file system that went into forced_shutdown as
* the result of an unmount..
*/
spin_lock(&log->l_icloglock);
iclog = log->l_iclog;
atomic_inc(&iclog->ic_refcnt);
xlog_state_want_sync(log, iclog);
spin_unlock(&log->l_icloglock);
error = xlog_state_release_iclog(log, iclog);
spin_lock(&log->l_icloglock);
if ( ! ( iclog->ic_state == XLOG_STATE_ACTIVE
|| iclog->ic_state == XLOG_STATE_DIRTY
|| iclog->ic_state == XLOG_STATE_IOERROR) ) {
sv_wait(&iclog->ic_force_wait, PMEM,
&log->l_icloglock, s);
} else {
spin_unlock(&log->l_icloglock);
}
}
return error;
} /* xfs_log_unmount_write */
/*
* Deallocate log structures for unmount/relocation.
*
* We need to stop the aild from running before we destroy
* and deallocate the log as the aild references the log.
*/
void
xfs_log_unmount(xfs_mount_t *mp)
{
xfs_trans_ail_destroy(mp);
xlog_dealloc_log(mp->m_log);
}
void
xfs_log_item_init(
struct xfs_mount *mp,
struct xfs_log_item *item,
int type,
struct xfs_item_ops *ops)
{
item->li_mountp = mp;
item->li_ailp = mp->m_ail;
item->li_type = type;
item->li_ops = ops;
}
/*
* Write region vectors to log. The write happens using the space reservation
* of the ticket (tic). It is not a requirement that all writes for a given
* transaction occur with one call to xfs_log_write(). However, it is important
* to note that the transaction reservation code makes an assumption about the
* number of log headers a transaction requires that may be violated if you
* don't pass all the transaction vectors in one call....
*/
int
xfs_log_write(
struct xfs_mount *mp,
struct xfs_log_iovec reg[],
int nentries,
struct xlog_ticket *tic,
xfs_lsn_t *start_lsn)
{
struct log *log = mp->m_log;
int error;
if (XLOG_FORCED_SHUTDOWN(log))
return XFS_ERROR(EIO);
error = xlog_write(mp, reg, nentries, tic, start_lsn, NULL, 0);
if (error)
xfs_force_shutdown(mp, SHUTDOWN_LOG_IO_ERROR);
return error;
}
void
xfs_log_move_tail(xfs_mount_t *mp,
xfs_lsn_t tail_lsn)
{
xlog_ticket_t *tic;
xlog_t *log = mp->m_log;
int need_bytes, free_bytes, cycle, bytes;
if (XLOG_FORCED_SHUTDOWN(log))
return;
if (tail_lsn == 0) {
/* needed since sync_lsn is 64 bits */
spin_lock(&log->l_icloglock);
tail_lsn = log->l_last_sync_lsn;
spin_unlock(&log->l_icloglock);
}
spin_lock(&log->l_grant_lock);
/* Also an invalid lsn. 1 implies that we aren't passing in a valid
* tail_lsn.
*/
if (tail_lsn != 1) {
log->l_tail_lsn = tail_lsn;
}
if ((tic = log->l_write_headq)) {
#ifdef DEBUG
if (log->l_flags & XLOG_ACTIVE_RECOVERY)
panic("Recovery problem");
#endif
cycle = log->l_grant_write_cycle;
bytes = log->l_grant_write_bytes;
free_bytes = xlog_space_left(log, cycle, bytes);
do {
ASSERT(tic->t_flags & XLOG_TIC_PERM_RESERV);
if (free_bytes < tic->t_unit_res && tail_lsn != 1)
break;
tail_lsn = 0;
free_bytes -= tic->t_unit_res;
sv_signal(&tic->t_wait);
tic = tic->t_next;
} while (tic != log->l_write_headq);
}
if ((tic = log->l_reserve_headq)) {
#ifdef DEBUG
if (log->l_flags & XLOG_ACTIVE_RECOVERY)
panic("Recovery problem");
#endif
cycle = log->l_grant_reserve_cycle;
bytes = log->l_grant_reserve_bytes;
free_bytes = xlog_space_left(log, cycle, bytes);
do {
if (tic->t_flags & XLOG_TIC_PERM_RESERV)
need_bytes = tic->t_unit_res*tic->t_cnt;
else
need_bytes = tic->t_unit_res;
if (free_bytes < need_bytes && tail_lsn != 1)
break;
tail_lsn = 0;
free_bytes -= need_bytes;
sv_signal(&tic->t_wait);
tic = tic->t_next;
} while (tic != log->l_reserve_headq);
}
spin_unlock(&log->l_grant_lock);
} /* xfs_log_move_tail */
/*
* Determine if we have a transaction that has gone to disk
* that needs to be covered. To begin the transition to the idle state
* firstly the log needs to be idle (no AIL and nothing in the iclogs).
* If we are then in a state where covering is needed, the caller is informed
* that dummy transactions are required to move the log into the idle state.
*
* Because this is called as part of the sync process, we should also indicate
* that dummy transactions should be issued in anything but the covered or
* idle states. This ensures that the log tail is accurately reflected in
* the log at the end of the sync, hence if a crash occurrs avoids replay
* of transactions where the metadata is already on disk.
*/
int
xfs_log_need_covered(xfs_mount_t *mp)
{
int needed = 0;
xlog_t *log = mp->m_log;
if (!xfs_fs_writable(mp))
return 0;
spin_lock(&log->l_icloglock);
switch (log->l_covered_state) {
case XLOG_STATE_COVER_DONE:
case XLOG_STATE_COVER_DONE2:
case XLOG_STATE_COVER_IDLE:
break;
case XLOG_STATE_COVER_NEED:
case XLOG_STATE_COVER_NEED2:
if (!xfs_trans_ail_tail(log->l_ailp) &&
xlog_iclogs_empty(log)) {
if (log->l_covered_state == XLOG_STATE_COVER_NEED)
log->l_covered_state = XLOG_STATE_COVER_DONE;
else
log->l_covered_state = XLOG_STATE_COVER_DONE2;
}
/* FALLTHRU */
default:
needed = 1;
break;
}
spin_unlock(&log->l_icloglock);
return needed;
}
/******************************************************************************
*
* local routines
*
******************************************************************************
*/
/* xfs_trans_tail_ail returns 0 when there is nothing in the list.
* The log manager must keep track of the last LR which was committed
* to disk. The lsn of this LR will become the new tail_lsn whenever
* xfs_trans_tail_ail returns 0. If we don't do this, we run into
* the situation where stuff could be written into the log but nothing
* was ever in the AIL when asked. Eventually, we panic since the
* tail hits the head.
*
* We may be holding the log iclog lock upon entering this routine.
*/
xfs_lsn_t
xlog_assign_tail_lsn(xfs_mount_t *mp)
{
xfs_lsn_t tail_lsn;
xlog_t *log = mp->m_log;
tail_lsn = xfs_trans_ail_tail(mp->m_ail);
spin_lock(&log->l_grant_lock);
if (tail_lsn != 0) {
log->l_tail_lsn = tail_lsn;
} else {
tail_lsn = log->l_tail_lsn = log->l_last_sync_lsn;
}
spin_unlock(&log->l_grant_lock);
return tail_lsn;
} /* xlog_assign_tail_lsn */
/*
* Return the space in the log between the tail and the head. The head
* is passed in the cycle/bytes formal parms. In the special case where
* the reserve head has wrapped passed the tail, this calculation is no
* longer valid. In this case, just return 0 which means there is no space
* in the log. This works for all places where this function is called
* with the reserve head. Of course, if the write head were to ever
* wrap the tail, we should blow up. Rather than catch this case here,
* we depend on other ASSERTions in other parts of the code. XXXmiken
*
* This code also handles the case where the reservation head is behind
* the tail. The details of this case are described below, but the end
* result is that we return the size of the log as the amount of space left.
*/
STATIC int
xlog_space_left(xlog_t *log, int cycle, int bytes)
{
int free_bytes;
int tail_bytes;
int tail_cycle;
tail_bytes = BBTOB(BLOCK_LSN(log->l_tail_lsn));
tail_cycle = CYCLE_LSN(log->l_tail_lsn);
if ((tail_cycle == cycle) && (bytes >= tail_bytes)) {
free_bytes = log->l_logsize - (bytes - tail_bytes);
} else if ((tail_cycle + 1) < cycle) {
return 0;
} else if (tail_cycle < cycle) {
ASSERT(tail_cycle == (cycle - 1));
free_bytes = tail_bytes - bytes;
} else {
/*
* The reservation head is behind the tail.
* In this case we just want to return the size of the
* log as the amount of space left.
*/
xfs_fs_cmn_err(CE_ALERT, log->l_mp,
"xlog_space_left: head behind tail\n"
" tail_cycle = %d, tail_bytes = %d\n"
" GH cycle = %d, GH bytes = %d",
tail_cycle, tail_bytes, cycle, bytes);
ASSERT(0);
free_bytes = log->l_logsize;
}
return free_bytes;
} /* xlog_space_left */
/*
* Log function which is called when an io completes.
*
* The log manager needs its own routine, in order to control what
* happens with the buffer after the write completes.
*/
void
xlog_iodone(xfs_buf_t *bp)
{
xlog_in_core_t *iclog;
xlog_t *l;
int aborted;
iclog = XFS_BUF_FSPRIVATE(bp, xlog_in_core_t *);
ASSERT(XFS_BUF_FSPRIVATE2(bp, unsigned long) == (unsigned long) 2);
XFS_BUF_SET_FSPRIVATE2(bp, (unsigned long)1);
aborted = 0;
l = iclog->ic_log;
/*
* If the _XFS_BARRIER_FAILED flag was set by a lower
* layer, it means the underlying device no longer supports
* barrier I/O. Warn loudly and turn off barriers.
*/
if (bp->b_flags & _XFS_BARRIER_FAILED) {
bp->b_flags &= ~_XFS_BARRIER_FAILED;
l->l_mp->m_flags &= ~XFS_MOUNT_BARRIER;
xfs_fs_cmn_err(CE_WARN, l->l_mp,
"xlog_iodone: Barriers are no longer supported"
" by device. Disabling barriers\n");
}
/*
* Race to shutdown the filesystem if we see an error.
*/
if (XFS_TEST_ERROR((XFS_BUF_GETERROR(bp)), l->l_mp,
XFS_ERRTAG_IODONE_IOERR, XFS_RANDOM_IODONE_IOERR)) {
xfs_ioerror_alert("xlog_iodone", l->l_mp, bp, XFS_BUF_ADDR(bp));
XFS_BUF_STALE(bp);
xfs_force_shutdown(l->l_mp, SHUTDOWN_LOG_IO_ERROR);
/*
* This flag will be propagated to the trans-committed
* callback routines to let them know that the log-commit
* didn't succeed.
*/
aborted = XFS_LI_ABORTED;
} else if (iclog->ic_state & XLOG_STATE_IOERROR) {
aborted = XFS_LI_ABORTED;
}
/* log I/O is always issued ASYNC */
ASSERT(XFS_BUF_ISASYNC(bp));
xlog_state_done_syncing(iclog, aborted);
/*
* do not reference the buffer (bp) here as we could race
* with it being freed after writing the unmount record to the
* log.
*/
} /* xlog_iodone */
/*
* Return size of each in-core log record buffer.
*
* All machines get 8 x 32kB buffers by default, unless tuned otherwise.
*
* If the filesystem blocksize is too large, we may need to choose a
* larger size since the directory code currently logs entire blocks.
*/
STATIC void
xlog_get_iclog_buffer_size(xfs_mount_t *mp,
xlog_t *log)
{
int size;
int xhdrs;
if (mp->m_logbufs <= 0)
log->l_iclog_bufs = XLOG_MAX_ICLOGS;
else
log->l_iclog_bufs = mp->m_logbufs;
/*
* Buffer size passed in from mount system call.
*/
if (mp->m_logbsize > 0) {
size = log->l_iclog_size = mp->m_logbsize;
log->l_iclog_size_log = 0;
while (size != 1) {
log->l_iclog_size_log++;
size >>= 1;
}
if (xfs_sb_version_haslogv2(&mp->m_sb)) {
/* # headers = size / 32k
* one header holds cycles from 32k of data
*/
xhdrs = mp->m_logbsize / XLOG_HEADER_CYCLE_SIZE;
if (mp->m_logbsize % XLOG_HEADER_CYCLE_SIZE)
xhdrs++;
log->l_iclog_hsize = xhdrs << BBSHIFT;
log->l_iclog_heads = xhdrs;
} else {
ASSERT(mp->m_logbsize <= XLOG_BIG_RECORD_BSIZE);
log->l_iclog_hsize = BBSIZE;
log->l_iclog_heads = 1;
}
goto done;
}
/* All machines use 32kB buffers by default. */
log->l_iclog_size = XLOG_BIG_RECORD_BSIZE;
log->l_iclog_size_log = XLOG_BIG_RECORD_BSHIFT;
/* the default log size is 16k or 32k which is one header sector */
log->l_iclog_hsize = BBSIZE;
log->l_iclog_heads = 1;
done:
/* are we being asked to make the sizes selected above visible? */
if (mp->m_logbufs == 0)
mp->m_logbufs = log->l_iclog_bufs;
if (mp->m_logbsize == 0)
mp->m_logbsize = log->l_iclog_size;
} /* xlog_get_iclog_buffer_size */
/*
* This routine initializes some of the log structure for a given mount point.
* Its primary purpose is to fill in enough, so recovery can occur. However,
* some other stuff may be filled in too.
*/
STATIC xlog_t *
xlog_alloc_log(xfs_mount_t *mp,
xfs_buftarg_t *log_target,
xfs_daddr_t blk_offset,
int num_bblks)
{
xlog_t *log;
xlog_rec_header_t *head;
xlog_in_core_t **iclogp;
xlog_in_core_t *iclog, *prev_iclog=NULL;
xfs_buf_t *bp;
int i;
int iclogsize;
int error = ENOMEM;
log = kmem_zalloc(sizeof(xlog_t), KM_MAYFAIL);
if (!log) {
xlog_warn("XFS: Log allocation failed: No memory!");
goto out;
}
log->l_mp = mp;
log->l_targ = log_target;
log->l_logsize = BBTOB(num_bblks);
log->l_logBBstart = blk_offset;
log->l_logBBsize = num_bblks;
log->l_covered_state = XLOG_STATE_COVER_IDLE;
log->l_flags |= XLOG_ACTIVE_RECOVERY;
log->l_prev_block = -1;
log->l_tail_lsn = xlog_assign_lsn(1, 0);
/* log->l_tail_lsn = 0x100000000LL; cycle = 1; current block = 0 */
log->l_last_sync_lsn = log->l_tail_lsn;
log->l_curr_cycle = 1; /* 0 is bad since this is initial value */
log->l_grant_reserve_cycle = 1;
log->l_grant_write_cycle = 1;
error = EFSCORRUPTED;
if (xfs_sb_version_hassector(&mp->m_sb)) {
log->l_sectbb_log = mp->m_sb.sb_logsectlog - BBSHIFT;
if (log->l_sectbb_log < 0 ||
log->l_sectbb_log > mp->m_sectbb_log) {
xlog_warn("XFS: Log sector size (0x%x) out of range.",
log->l_sectbb_log);
goto out_free_log;
}
/* for larger sector sizes, must have v2 or external log */
if (log->l_sectbb_log != 0 &&
(log->l_logBBstart != 0 &&
!xfs_sb_version_haslogv2(&mp->m_sb))) {
xlog_warn("XFS: log sector size (0x%x) invalid "
"for configuration.", log->l_sectbb_log);
goto out_free_log;
}
if (mp->m_sb.sb_logsectlog < BBSHIFT) {
xlog_warn("XFS: Log sector log (0x%x) too small.",
mp->m_sb.sb_logsectlog);
goto out_free_log;
}
}
log->l_sectbb_mask = (1 << log->l_sectbb_log) - 1;
xlog_get_iclog_buffer_size(mp, log);
error = ENOMEM;
bp = xfs_buf_get_empty(log->l_iclog_size, mp->m_logdev_targp);
if (!bp)
goto out_free_log;
XFS_BUF_SET_IODONE_FUNC(bp, xlog_iodone);
XFS_BUF_SET_FSPRIVATE2(bp, (unsigned long)1);
ASSERT(XFS_BUF_ISBUSY(bp));
ASSERT(XFS_BUF_VALUSEMA(bp) <= 0);
log->l_xbuf = bp;
spin_lock_init(&log->l_icloglock);
spin_lock_init(&log->l_grant_lock);
sv_init(&log->l_flush_wait, 0, "flush_wait");
/* log record size must be multiple of BBSIZE; see xlog_rec_header_t */
ASSERT((XFS_BUF_SIZE(bp) & BBMASK) == 0);
iclogp = &log->l_iclog;
/*
* The amount of memory to allocate for the iclog structure is
* rather funky due to the way the structure is defined. It is
* done this way so that we can use different sizes for machines
* with different amounts of memory. See the definition of
* xlog_in_core_t in xfs_log_priv.h for details.
*/
iclogsize = log->l_iclog_size;
ASSERT(log->l_iclog_size >= 4096);
for (i=0; i < log->l_iclog_bufs; i++) {
*iclogp = kmem_zalloc(sizeof(xlog_in_core_t), KM_MAYFAIL);
if (!*iclogp)
goto out_free_iclog;
iclog = *iclogp;
iclog->ic_prev = prev_iclog;
prev_iclog = iclog;
bp = xfs_buf_get_noaddr(log->l_iclog_size, mp->m_logdev_targp);
if (!bp)
goto out_free_iclog;
if (!XFS_BUF_CPSEMA(bp))
ASSERT(0);
XFS_BUF_SET_IODONE_FUNC(bp, xlog_iodone);
XFS_BUF_SET_FSPRIVATE2(bp, (unsigned long)1);
iclog->ic_bp = bp;
iclog->ic_data = bp->b_addr;
#ifdef DEBUG
log->l_iclog_bak[i] = (xfs_caddr_t)&(iclog->ic_header);
#endif
head = &iclog->ic_header;
memset(head, 0, sizeof(xlog_rec_header_t));
head->h_magicno = cpu_to_be32(XLOG_HEADER_MAGIC_NUM);
head->h_version = cpu_to_be32(
xfs_sb_version_haslogv2(&log->l_mp->m_sb) ? 2 : 1);
head->h_size = cpu_to_be32(log->l_iclog_size);
/* new fields */
head->h_fmt = cpu_to_be32(XLOG_FMT);
memcpy(&head->h_fs_uuid, &mp->m_sb.sb_uuid, sizeof(uuid_t));
iclog->ic_size = XFS_BUF_SIZE(bp) - log->l_iclog_hsize;
iclog->ic_state = XLOG_STATE_ACTIVE;
iclog->ic_log = log;
atomic_set(&iclog->ic_refcnt, 0);
spin_lock_init(&iclog->ic_callback_lock);
iclog->ic_callback_tail = &(iclog->ic_callback);
iclog->ic_datap = (char *)iclog->ic_data + log->l_iclog_hsize;
ASSERT(XFS_BUF_ISBUSY(iclog->ic_bp));
ASSERT(XFS_BUF_VALUSEMA(iclog->ic_bp) <= 0);
sv_init(&iclog->ic_force_wait, SV_DEFAULT, "iclog-force");
sv_init(&iclog->ic_write_wait, SV_DEFAULT, "iclog-write");
iclogp = &iclog->ic_next;
}
*iclogp = log->l_iclog; /* complete ring */
log->l_iclog->ic_prev = prev_iclog; /* re-write 1st prev ptr */
return log;
out_free_iclog:
for (iclog = log->l_iclog; iclog; iclog = prev_iclog) {
prev_iclog = iclog->ic_next;
if (iclog->ic_bp) {
sv_destroy(&iclog->ic_force_wait);
sv_destroy(&iclog->ic_write_wait);
xfs_buf_free(iclog->ic_bp);
}
kmem_free(iclog);
}
spinlock_destroy(&log->l_icloglock);
spinlock_destroy(&log->l_grant_lock);
xfs_buf_free(log->l_xbuf);
out_free_log:
kmem_free(log);
out:
return ERR_PTR(-error);
} /* xlog_alloc_log */
/*
* Write out the commit record of a transaction associated with the given
* ticket. Return the lsn of the commit record.
*/
STATIC int
xlog_commit_record(xfs_mount_t *mp,
xlog_ticket_t *ticket,
xlog_in_core_t **iclog,
xfs_lsn_t *commitlsnp)
{
int error;
xfs_log_iovec_t reg[1];
reg[0].i_addr = NULL;
reg[0].i_len = 0;
reg[0].i_type = XLOG_REG_TYPE_COMMIT;
ASSERT_ALWAYS(iclog);
if ((error = xlog_write(mp, reg, 1, ticket, commitlsnp,
iclog, XLOG_COMMIT_TRANS))) {
xfs_force_shutdown(mp, SHUTDOWN_LOG_IO_ERROR);
}
return error;
} /* xlog_commit_record */
/*
* Push on the buffer cache code if we ever use more than 75% of the on-disk
* log space. This code pushes on the lsn which would supposedly free up
* the 25% which we want to leave free. We may need to adopt a policy which
* pushes on an lsn which is further along in the log once we reach the high
* water mark. In this manner, we would be creating a low water mark.
*/
STATIC void
xlog_grant_push_ail(xfs_mount_t *mp,
int need_bytes)
{
xlog_t *log = mp->m_log; /* pointer to the log */
xfs_lsn_t tail_lsn; /* lsn of the log tail */
xfs_lsn_t threshold_lsn = 0; /* lsn we'd like to be at */
int free_blocks; /* free blocks left to write to */
int free_bytes; /* free bytes left to write to */
int threshold_block; /* block in lsn we'd like to be at */
int threshold_cycle; /* lsn cycle we'd like to be at */
int free_threshold;
ASSERT(BTOBB(need_bytes) < log->l_logBBsize);
spin_lock(&log->l_grant_lock);
free_bytes = xlog_space_left(log,
log->l_grant_reserve_cycle,
log->l_grant_reserve_bytes);
tail_lsn = log->l_tail_lsn;
free_blocks = BTOBBT(free_bytes);
/*
* Set the threshold for the minimum number of free blocks in the
* log to the maximum of what the caller needs, one quarter of the
* log, and 256 blocks.
*/
free_threshold = BTOBB(need_bytes);
free_threshold = MAX(free_threshold, (log->l_logBBsize >> 2));
free_threshold = MAX(free_threshold, 256);
if (free_blocks < free_threshold) {
threshold_block = BLOCK_LSN(tail_lsn) + free_threshold;
threshold_cycle = CYCLE_LSN(tail_lsn);
if (threshold_block >= log->l_logBBsize) {
threshold_block -= log->l_logBBsize;
threshold_cycle += 1;
}
threshold_lsn = xlog_assign_lsn(threshold_cycle, threshold_block);
/* Don't pass in an lsn greater than the lsn of the last
* log record known to be on disk.
*/
if (XFS_LSN_CMP(threshold_lsn, log->l_last_sync_lsn) > 0)
threshold_lsn = log->l_last_sync_lsn;
}
spin_unlock(&log->l_grant_lock);
/*
* Get the transaction layer to kick the dirty buffers out to
* disk asynchronously. No point in trying to do this if
* the filesystem is shutting down.
*/
if (threshold_lsn &&
!XLOG_FORCED_SHUTDOWN(log))
xfs_trans_ail_push(log->l_ailp, threshold_lsn);
} /* xlog_grant_push_ail */
/*
* The bdstrat callback function for log bufs. This gives us a central
* place to trap bufs in case we get hit by a log I/O error and need to
* shutdown. Actually, in practice, even when we didn't get a log error,
* we transition the iclogs to IOERROR state *after* flushing all existing
* iclogs to disk. This is because we don't want anymore new transactions to be
* started or completed afterwards.
*/
STATIC int
xlog_bdstrat(
struct xfs_buf *bp)
{
struct xlog_in_core *iclog;
iclog = XFS_BUF_FSPRIVATE(bp, xlog_in_core_t *);
if (iclog->ic_state & XLOG_STATE_IOERROR) {
XFS_BUF_ERROR(bp, EIO);
XFS_BUF_STALE(bp);
xfs_biodone(bp);
/*
* It would seem logical to return EIO here, but we rely on
* the log state machine to propagate I/O errors instead of
* doing it here.
*/
return 0;
}
bp->b_flags |= _XBF_RUN_QUEUES;
xfs_buf_iorequest(bp);
return 0;
}
/*
* Flush out the in-core log (iclog) to the on-disk log in an asynchronous
* fashion. Previously, we should have moved the current iclog
* ptr in the log to point to the next available iclog. This allows further
* write to continue while this code syncs out an iclog ready to go.
* Before an in-core log can be written out, the data section must be scanned
* to save away the 1st word of each BBSIZE block into the header. We replace
* it with the current cycle count. Each BBSIZE block is tagged with the
* cycle count because there in an implicit assumption that drives will
* guarantee that entire 512 byte blocks get written at once. In other words,
* we can't have part of a 512 byte block written and part not written. By
* tagging each block, we will know which blocks are valid when recovering
* after an unclean shutdown.
*
* This routine is single threaded on the iclog. No other thread can be in
* this routine with the same iclog. Changing contents of iclog can there-
* fore be done without grabbing the state machine lock. Updating the global
* log will require grabbing the lock though.
*
* The entire log manager uses a logical block numbering scheme. Only
* log_sync (and then only bwrite()) know about the fact that the log may
* not start with block zero on a given device. The log block start offset
* is added immediately before calling bwrite().
*/
STATIC int
xlog_sync(xlog_t *log,
xlog_in_core_t *iclog)
{
xfs_caddr_t dptr; /* pointer to byte sized element */
xfs_buf_t *bp;
int i;
uint count; /* byte count of bwrite */
uint count_init; /* initial count before roundup */
int roundoff; /* roundoff to BB or stripe */
int split = 0; /* split write into two regions */
int error;
int v2 = xfs_sb_version_haslogv2(&log->l_mp->m_sb);
XFS_STATS_INC(xs_log_writes);
ASSERT(atomic_read(&iclog->ic_refcnt) == 0);
/* Add for LR header */
count_init = log->l_iclog_hsize + iclog->ic_offset;
/* Round out the log write size */
if (v2 && log->l_mp->m_sb.sb_logsunit > 1) {
/* we have a v2 stripe unit to use */
count = XLOG_LSUNITTOB(log, XLOG_BTOLSUNIT(log, count_init));
} else {
count = BBTOB(BTOBB(count_init));
}
roundoff = count - count_init;
ASSERT(roundoff >= 0);
ASSERT((v2 && log->l_mp->m_sb.sb_logsunit > 1 &&
roundoff < log->l_mp->m_sb.sb_logsunit)
||
(log->l_mp->m_sb.sb_logsunit <= 1 &&
roundoff < BBTOB(1)));
/* move grant heads by roundoff in sync */
spin_lock(&log->l_grant_lock);
xlog_grant_add_space(log, roundoff);
spin_unlock(&log->l_grant_lock);
/* put cycle number in every block */
xlog_pack_data(log, iclog, roundoff);
/* real byte length */
if (v2) {
iclog->ic_header.h_len =
cpu_to_be32(iclog->ic_offset + roundoff);
} else {
iclog->ic_header.h_len =
cpu_to_be32(iclog->ic_offset);
}
bp = iclog->ic_bp;
ASSERT(XFS_BUF_FSPRIVATE2(bp, unsigned long) == (unsigned long)1);
XFS_BUF_SET_FSPRIVATE2(bp, (unsigned long)2);
XFS_BUF_SET_ADDR(bp, BLOCK_LSN(be64_to_cpu(iclog->ic_header.h_lsn)));
XFS_STATS_ADD(xs_log_blocks, BTOBB(count));
/* Do we need to split this write into 2 parts? */
if (XFS_BUF_ADDR(bp) + BTOBB(count) > log->l_logBBsize) {
split = count - (BBTOB(log->l_logBBsize - XFS_BUF_ADDR(bp)));
count = BBTOB(log->l_logBBsize - XFS_BUF_ADDR(bp));
iclog->ic_bwritecnt = 2; /* split into 2 writes */
} else {
iclog->ic_bwritecnt = 1;
}
XFS_BUF_SET_COUNT(bp, count);
XFS_BUF_SET_FSPRIVATE(bp, iclog); /* save for later */
XFS_BUF_ZEROFLAGS(bp);
XFS_BUF_BUSY(bp);
XFS_BUF_ASYNC(bp);
bp->b_flags |= XBF_LOG_BUFFER;
/*
* Do an ordered write for the log block.
* Its unnecessary to flush the first split block in the log wrap case.
*/
if (!split && (log->l_mp->m_flags & XFS_MOUNT_BARRIER))
XFS_BUF_ORDERED(bp);
ASSERT(XFS_BUF_ADDR(bp) <= log->l_logBBsize-1);
ASSERT(XFS_BUF_ADDR(bp) + BTOBB(count) <= log->l_logBBsize);
xlog_verify_iclog(log, iclog, count, B_TRUE);
/* account for log which doesn't start at block #0 */
XFS_BUF_SET_ADDR(bp, XFS_BUF_ADDR(bp) + log->l_logBBstart);
/*
* Don't call xfs_bwrite here. We do log-syncs even when the filesystem
* is shutting down.
*/
XFS_BUF_WRITE(bp);
if ((error = xlog_bdstrat(bp))) {
xfs_ioerror_alert("xlog_sync", log->l_mp, bp,
XFS_BUF_ADDR(bp));
return error;
}
if (split) {
bp = iclog->ic_log->l_xbuf;
ASSERT(XFS_BUF_FSPRIVATE2(bp, unsigned long) ==
(unsigned long)1);
XFS_BUF_SET_FSPRIVATE2(bp, (unsigned long)2);
XFS_BUF_SET_ADDR(bp, 0); /* logical 0 */
XFS_BUF_SET_PTR(bp, (xfs_caddr_t)((__psint_t)&(iclog->ic_header)+
(__psint_t)count), split);
XFS_BUF_SET_FSPRIVATE(bp, iclog);
XFS_BUF_ZEROFLAGS(bp);
XFS_BUF_BUSY(bp);
XFS_BUF_ASYNC(bp);
bp->b_flags |= XBF_LOG_BUFFER;
if (log->l_mp->m_flags & XFS_MOUNT_BARRIER)
XFS_BUF_ORDERED(bp);
dptr = XFS_BUF_PTR(bp);
/*
* Bump the cycle numbers at the start of each block
* since this part of the buffer is at the start of
* a new cycle. Watch out for the header magic number
* case, though.
*/
for (i = 0; i < split; i += BBSIZE) {
be32_add_cpu((__be32 *)dptr, 1);
if (be32_to_cpu(*(__be32 *)dptr) == XLOG_HEADER_MAGIC_NUM)
be32_add_cpu((__be32 *)dptr, 1);
dptr += BBSIZE;
}
ASSERT(XFS_BUF_ADDR(bp) <= log->l_logBBsize-1);
ASSERT(XFS_BUF_ADDR(bp) + BTOBB(count) <= log->l_logBBsize);
/* account for internal log which doesn't start at block #0 */
XFS_BUF_SET_ADDR(bp, XFS_BUF_ADDR(bp) + log->l_logBBstart);
XFS_BUF_WRITE(bp);
if ((error = xlog_bdstrat(bp))) {
xfs_ioerror_alert("xlog_sync (split)", log->l_mp,
bp, XFS_BUF_ADDR(bp));
return error;
}
}
return 0;
} /* xlog_sync */
/*
* Deallocate a log structure
*/
STATIC void
xlog_dealloc_log(xlog_t *log)
{
xlog_in_core_t *iclog, *next_iclog;
int i;
iclog = log->l_iclog;
for (i=0; i<log->l_iclog_bufs; i++) {
sv_destroy(&iclog->ic_force_wait);
sv_destroy(&iclog->ic_write_wait);
xfs_buf_free(iclog->ic_bp);
next_iclog = iclog->ic_next;
kmem_free(iclog);
iclog = next_iclog;
}
spinlock_destroy(&log->l_icloglock);
spinlock_destroy(&log->l_grant_lock);
xfs_buf_free(log->l_xbuf);
log->l_mp->m_log = NULL;
kmem_free(log);
} /* xlog_dealloc_log */
/*
* Update counters atomically now that memcpy is done.
*/
/* ARGSUSED */
static inline void
xlog_state_finish_copy(xlog_t *log,
xlog_in_core_t *iclog,
int record_cnt,
int copy_bytes)
{
spin_lock(&log->l_icloglock);
be32_add_cpu(&iclog->ic_header.h_num_logops, record_cnt);
iclog->ic_offset += copy_bytes;
spin_unlock(&log->l_icloglock);
} /* xlog_state_finish_copy */
/*
* print out info relating to regions written which consume
* the reservation
*/
STATIC void
xlog_print_tic_res(xfs_mount_t *mp, xlog_ticket_t *ticket)
{
uint i;
uint ophdr_spc = ticket->t_res_num_ophdrs * (uint)sizeof(xlog_op_header_t);
/* match with XLOG_REG_TYPE_* in xfs_log.h */
static char *res_type_str[XLOG_REG_TYPE_MAX] = {
"bformat",
"bchunk",
"efi_format",
"efd_format",
"iformat",
"icore",
"iext",
"ibroot",
"ilocal",
"iattr_ext",
"iattr_broot",
"iattr_local",
"qformat",
"dquot",
"quotaoff",
"LR header",
"unmount",
"commit",
"trans header"
};
static char *trans_type_str[XFS_TRANS_TYPE_MAX] = {
"SETATTR_NOT_SIZE",
"SETATTR_SIZE",
"INACTIVE",
"CREATE",
"CREATE_TRUNC",
"TRUNCATE_FILE",
"REMOVE",
"LINK",
"RENAME",
"MKDIR",
"RMDIR",
"SYMLINK",
"SET_DMATTRS",
"GROWFS",
"STRAT_WRITE",
"DIOSTRAT",
"WRITE_SYNC",
"WRITEID",
"ADDAFORK",
"ATTRINVAL",
"ATRUNCATE",
"ATTR_SET",
"ATTR_RM",
"ATTR_FLAG",
"CLEAR_AGI_BUCKET",
"QM_SBCHANGE",
"DUMMY1",
"DUMMY2",
"QM_QUOTAOFF",
"QM_DQALLOC",
"QM_SETQLIM",
"QM_DQCLUSTER",
"QM_QINOCREATE",
"QM_QUOTAOFF_END",
"SB_UNIT",
"FSYNC_TS",
"GROWFSRT_ALLOC",
"GROWFSRT_ZERO",
"GROWFSRT_FREE",
"SWAPEXT"
};
xfs_fs_cmn_err(CE_WARN, mp,
"xfs_log_write: reservation summary:\n"
" trans type = %s (%u)\n"
" unit res = %d bytes\n"
" current res = %d bytes\n"
" total reg = %u bytes (o/flow = %u bytes)\n"
" ophdrs = %u (ophdr space = %u bytes)\n"
" ophdr + reg = %u bytes\n"
" num regions = %u\n",
((ticket->t_trans_type <= 0 ||
ticket->t_trans_type > XFS_TRANS_TYPE_MAX) ?
"bad-trans-type" : trans_type_str[ticket->t_trans_type-1]),
ticket->t_trans_type,
ticket->t_unit_res,
ticket->t_curr_res,
ticket->t_res_arr_sum, ticket->t_res_o_flow,
ticket->t_res_num_ophdrs, ophdr_spc,
ticket->t_res_arr_sum +
ticket->t_res_o_flow + ophdr_spc,
ticket->t_res_num);
for (i = 0; i < ticket->t_res_num; i++) {
uint r_type = ticket->t_res_arr[i].r_type;
cmn_err(CE_WARN,
"region[%u]: %s - %u bytes\n",
i,
((r_type <= 0 || r_type > XLOG_REG_TYPE_MAX) ?
"bad-rtype" : res_type_str[r_type-1]),
ticket->t_res_arr[i].r_len);
}
}
/*
* Calculate the potential space needed by the log vector. Each region gets
* its own xlog_op_header_t and may need to be double word aligned.
*/
static int
xlog_write_calc_vec_length(
struct xlog_ticket *ticket,
struct xfs_log_iovec reg[],
int nentries)
{
int headers = 0;
int len = 0;
int i;
/* acct for start rec of xact */
if (ticket->t_flags & XLOG_TIC_INITED)
headers++;
for (i = 0; i < nentries; i++) {
/* each region gets >= 1 */
headers++;
len += reg[i].i_len;
xlog_tic_add_region(ticket, reg[i].i_len, reg[i].i_type);
}
ticket->t_res_num_ophdrs += headers;
len += headers * sizeof(struct xlog_op_header);
return len;
}
/*
* If first write for transaction, insert start record We can't be trying to
* commit if we are inited. We can't have any "partial_copy" if we are inited.
*/
static int
xlog_write_start_rec(
__psint_t ptr,
struct xlog_ticket *ticket)
{
struct xlog_op_header *ophdr = (struct xlog_op_header *)ptr;
if (!(ticket->t_flags & XLOG_TIC_INITED))
return 0;
ophdr->oh_tid = cpu_to_be32(ticket->t_tid);
ophdr->oh_clientid = ticket->t_clientid;
ophdr->oh_len = 0;
ophdr->oh_flags = XLOG_START_TRANS;
ophdr->oh_res2 = 0;
ticket->t_flags &= ~XLOG_TIC_INITED;
return sizeof(struct xlog_op_header);
}
static xlog_op_header_t *
xlog_write_setup_ophdr(
struct log *log,
__psint_t ptr,
struct xlog_ticket *ticket,
uint flags)
{
struct xlog_op_header *ophdr = (struct xlog_op_header *)ptr;
ophdr->oh_tid = cpu_to_be32(ticket->t_tid);
ophdr->oh_clientid = ticket->t_clientid;
ophdr->oh_res2 = 0;
/* are we copying a commit or unmount record? */
ophdr->oh_flags = flags;
/*
* We've seen logs corrupted with bad transaction client ids. This
* makes sure that XFS doesn't generate them on. Turn this into an EIO
* and shut down the filesystem.
*/
switch (ophdr->oh_clientid) {
case XFS_TRANSACTION:
case XFS_VOLUME:
case XFS_LOG:
break;
default:
xfs_fs_cmn_err(CE_WARN, log->l_mp,
"Bad XFS transaction clientid 0x%x in ticket 0x%p",
ophdr->oh_clientid, ticket);
return NULL;
}
return ophdr;
}
/*
* Set up the parameters of the region copy into the log. This has
* to handle region write split across multiple log buffers - this
* state is kept external to this function so that this code can
* can be written in an obvious, self documenting manner.
*/
static int
xlog_write_setup_copy(
struct xlog_ticket *ticket,
struct xlog_op_header *ophdr,
int space_available,
int space_required,
int *copy_off,
int *copy_len,
int *last_was_partial_copy,
int *bytes_consumed)
{
int still_to_copy;
still_to_copy = space_required - *bytes_consumed;
*copy_off = *bytes_consumed;
if (still_to_copy <= space_available) {
/* write of region completes here */
*copy_len = still_to_copy;
ophdr->oh_len = cpu_to_be32(*copy_len);
if (*last_was_partial_copy)
ophdr->oh_flags |= (XLOG_END_TRANS|XLOG_WAS_CONT_TRANS);
*last_was_partial_copy = 0;
*bytes_consumed = 0;
return 0;
}
/* partial write of region, needs extra log op header reservation */
*copy_len = space_available;
ophdr->oh_len = cpu_to_be32(*copy_len);
ophdr->oh_flags |= XLOG_CONTINUE_TRANS;
if (*last_was_partial_copy)
ophdr->oh_flags |= XLOG_WAS_CONT_TRANS;
*bytes_consumed += *copy_len;
(*last_was_partial_copy)++;
/* account for new log op header */
ticket->t_curr_res -= sizeof(struct xlog_op_header);
ticket->t_res_num_ophdrs++;
return sizeof(struct xlog_op_header);
}
static int
xlog_write_copy_finish(
struct log *log,
struct xlog_in_core *iclog,
uint flags,
int *record_cnt,
int *data_cnt,
int *partial_copy,
int *partial_copy_len,
int log_offset,
struct xlog_in_core **commit_iclog)
{
if (*partial_copy) {
/*
* This iclog has already been marked WANT_SYNC by
* xlog_state_get_iclog_space.
*/
xlog_state_finish_copy(log, iclog, *record_cnt, *data_cnt);
*record_cnt = 0;
*data_cnt = 0;
return xlog_state_release_iclog(log, iclog);
}
*partial_copy = 0;
*partial_copy_len = 0;
if (iclog->ic_size - log_offset <= sizeof(xlog_op_header_t)) {
/* no more space in this iclog - push it. */
xlog_state_finish_copy(log, iclog, *record_cnt, *data_cnt);
*record_cnt = 0;
*data_cnt = 0;
spin_lock(&log->l_icloglock);
xlog_state_want_sync(log, iclog);
spin_unlock(&log->l_icloglock);
if (!commit_iclog)
return xlog_state_release_iclog(log, iclog);
ASSERT(flags & XLOG_COMMIT_TRANS);
*commit_iclog = iclog;
}
return 0;
}
/*
* Write some region out to in-core log
*
* This will be called when writing externally provided regions or when
* writing out a commit record for a given transaction.
*
* General algorithm:
* 1. Find total length of this write. This may include adding to the
* lengths passed in.
* 2. Check whether we violate the tickets reservation.
* 3. While writing to this iclog
* A. Reserve as much space in this iclog as can get
* B. If this is first write, save away start lsn
* C. While writing this region:
* 1. If first write of transaction, write start record
* 2. Write log operation header (header per region)
* 3. Find out if we can fit entire region into this iclog
* 4. Potentially, verify destination memcpy ptr
* 5. Memcpy (partial) region
* 6. If partial copy, release iclog; otherwise, continue
* copying more regions into current iclog
* 4. Mark want sync bit (in simulation mode)
* 5. Release iclog for potential flush to on-disk log.
*
* ERRORS:
* 1. Panic if reservation is overrun. This should never happen since
* reservation amounts are generated internal to the filesystem.
* NOTES:
* 1. Tickets are single threaded data structures.
* 2. The XLOG_END_TRANS & XLOG_CONTINUE_TRANS flags are passed down to the
* syncing routine. When a single log_write region needs to span
* multiple in-core logs, the XLOG_CONTINUE_TRANS bit should be set
* on all log operation writes which don't contain the end of the
* region. The XLOG_END_TRANS bit is used for the in-core log
* operation which contains the end of the continued log_write region.
* 3. When xlog_state_get_iclog_space() grabs the rest of the current iclog,
* we don't really know exactly how much space will be used. As a result,
* we don't update ic_offset until the end when we know exactly how many
* bytes have been written out.
*/
STATIC int
xlog_write(
struct xfs_mount *mp,
struct xfs_log_iovec reg[],
int nentries,
struct xlog_ticket *ticket,
xfs_lsn_t *start_lsn,
struct xlog_in_core **commit_iclog,
uint flags)
{
xlog_t *log = mp->m_log;
xlog_in_core_t *iclog = NULL; /* ptr to current in-core log */
xlog_op_header_t *logop_head; /* ptr to log operation header */
__psint_t ptr; /* copy address into data region */
int len; /* # xlog_write() bytes 2 still copy */
int index; /* region index currently copying */
int log_offset; /* offset (from 0) into data region */
int start_rec_copy; /* # bytes to copy for start record */
int partial_copy; /* did we split a region? */
int partial_copy_len;/* # bytes copied if split region */
int copy_len; /* # bytes actually memcpy'ing */
int copy_off; /* # bytes from entry start */
int contwr; /* continued write of in-core log? */
int error;
int record_cnt = 0, data_cnt = 0;
partial_copy_len = partial_copy = 0;
contwr = *start_lsn = 0;
len = xlog_write_calc_vec_length(ticket, reg, nentries);
if (ticket->t_curr_res < len) {
xlog_print_tic_res(mp, ticket);
#ifdef DEBUG
xlog_panic(
"xfs_log_write: reservation ran out. Need to up reservation");
#else
/* Customer configurable panic */
xfs_cmn_err(XFS_PTAG_LOGRES, CE_ALERT, mp,
"xfs_log_write: reservation ran out. Need to up reservation");
/* If we did not panic, shutdown the filesystem */
xfs_force_shutdown(mp, SHUTDOWN_CORRUPT_INCORE);
#endif
} else
ticket->t_curr_res -= len;
for (index = 0; index < nentries; ) {
if ((error = xlog_state_get_iclog_space(log, len, &iclog, ticket,
&contwr, &log_offset)))
return error;
ASSERT(log_offset <= iclog->ic_size - 1);
ptr = (__psint_t) ((char *)iclog->ic_datap+log_offset);
/* start_lsn is the first lsn written to. That's all we need. */
if (! *start_lsn)
*start_lsn = be64_to_cpu(iclog->ic_header.h_lsn);
/* This loop writes out as many regions as can fit in the amount
* of space which was allocated by xlog_state_get_iclog_space().
*/
while (index < nentries) {
ASSERT(reg[index].i_len % sizeof(__int32_t) == 0);
ASSERT((__psint_t)ptr % sizeof(__int32_t) == 0);
start_rec_copy = xlog_write_start_rec(ptr, ticket);
if (start_rec_copy) {
record_cnt++;
xlog_write_adv_cnt(ptr, len, log_offset, start_rec_copy);
}
logop_head = xlog_write_setup_ophdr(log, ptr, ticket, flags);
if (!logop_head)
return XFS_ERROR(EIO);
xlog_write_adv_cnt(ptr, len, log_offset, sizeof(xlog_op_header_t));
len += xlog_write_setup_copy(ticket, logop_head,
iclog->ic_size - log_offset,
reg[index].i_len, &copy_off,
&copy_len, &partial_copy,
&partial_copy_len);
xlog_verify_dest_ptr(log, ptr);
/* copy region */
ASSERT(copy_len >= 0);
memcpy((xfs_caddr_t)ptr, reg[index].i_addr + copy_off, copy_len);
xlog_write_adv_cnt(ptr, len, log_offset, copy_len);
/* make copy_len total bytes copied, including headers */
copy_len += start_rec_copy + sizeof(xlog_op_header_t);
record_cnt++;
data_cnt += contwr ? copy_len : 0;
error = xlog_write_copy_finish(log, iclog, flags,
&record_cnt, &data_cnt,
&partial_copy, &partial_copy_len,
log_offset, commit_iclog);
if (error)
return error;
/*
* if we had a partial copy, we need to get more iclog
* space but we don't want to increment the region
* index because there is still more is this region to write.
*
* If we completed writing this region, and we flushed
* the iclog (indicated by resetting of the record
* count), then we also need to get more log space. If
* this was the last record, though, we are done and
* can just return.
*/
if (partial_copy)
break;
index++;
if (record_cnt == 0) {
if (index == nentries)
return 0;
break;
}
} /* while (index < nentries) */
} /* for (index = 0; index < nentries; ) */
ASSERT(len == 0);
xlog_state_finish_copy(log, iclog, record_cnt, data_cnt);
if (commit_iclog) {
ASSERT(flags & XLOG_COMMIT_TRANS);
*commit_iclog = iclog;
return 0;
}
return xlog_state_release_iclog(log, iclog);
} /* xlog_write */
/*****************************************************************************
*
* State Machine functions
*
*****************************************************************************
*/
/* Clean iclogs starting from the head. This ordering must be
* maintained, so an iclog doesn't become ACTIVE beyond one that
* is SYNCING. This is also required to maintain the notion that we use
* a ordered wait queue to hold off would be writers to the log when every
* iclog is trying to sync to disk.
*
* State Change: DIRTY -> ACTIVE
*/
STATIC void
xlog_state_clean_log(xlog_t *log)
{
xlog_in_core_t *iclog;
int changed = 0;
iclog = log->l_iclog;
do {
if (iclog->ic_state == XLOG_STATE_DIRTY) {
iclog->ic_state = XLOG_STATE_ACTIVE;
iclog->ic_offset = 0;
ASSERT(iclog->ic_callback == NULL);
/*
* If the number of ops in this iclog indicate it just
* contains the dummy transaction, we can
* change state into IDLE (the second time around).
* Otherwise we should change the state into
* NEED a dummy.
* We don't need to cover the dummy.
*/
if (!changed &&
(be32_to_cpu(iclog->ic_header.h_num_logops) ==
XLOG_COVER_OPS)) {
changed = 1;
} else {
/*
* We have two dirty iclogs so start over
* This could also be num of ops indicates
* this is not the dummy going out.
*/
changed = 2;
}
iclog->ic_header.h_num_logops = 0;
memset(iclog->ic_header.h_cycle_data, 0,
sizeof(iclog->ic_header.h_cycle_data));
iclog->ic_header.h_lsn = 0;
} else if (iclog->ic_state == XLOG_STATE_ACTIVE)
/* do nothing */;
else
break; /* stop cleaning */
iclog = iclog->ic_next;
} while (iclog != log->l_iclog);
/* log is locked when we are called */
/*
* Change state for the dummy log recording.
* We usually go to NEED. But we go to NEED2 if the changed indicates
* we are done writing the dummy record.
* If we are done with the second dummy recored (DONE2), then
* we go to IDLE.
*/
if (changed) {
switch (log->l_covered_state) {
case XLOG_STATE_COVER_IDLE:
case XLOG_STATE_COVER_NEED:
case XLOG_STATE_COVER_NEED2:
log->l_covered_state = XLOG_STATE_COVER_NEED;
break;
case XLOG_STATE_COVER_DONE:
if (changed == 1)
log->l_covered_state = XLOG_STATE_COVER_NEED2;
else
log->l_covered_state = XLOG_STATE_COVER_NEED;
break;
case XLOG_STATE_COVER_DONE2:
if (changed == 1)
log->l_covered_state = XLOG_STATE_COVER_IDLE;
else
log->l_covered_state = XLOG_STATE_COVER_NEED;
break;
default:
ASSERT(0);
}
}
} /* xlog_state_clean_log */
STATIC xfs_lsn_t
xlog_get_lowest_lsn(
xlog_t *log)
{
xlog_in_core_t *lsn_log;
xfs_lsn_t lowest_lsn, lsn;
lsn_log = log->l_iclog;
lowest_lsn = 0;
do {
if (!(lsn_log->ic_state & (XLOG_STATE_ACTIVE|XLOG_STATE_DIRTY))) {
lsn = be64_to_cpu(lsn_log->ic_header.h_lsn);
if ((lsn && !lowest_lsn) ||
(XFS_LSN_CMP(lsn, lowest_lsn) < 0)) {
lowest_lsn = lsn;
}
}
lsn_log = lsn_log->ic_next;
} while (lsn_log != log->l_iclog);
return lowest_lsn;
}
STATIC void
xlog_state_do_callback(
xlog_t *log,
int aborted,
xlog_in_core_t *ciclog)
{
xlog_in_core_t *iclog;
xlog_in_core_t *first_iclog; /* used to know when we've
* processed all iclogs once */
xfs_log_callback_t *cb, *cb_next;
int flushcnt = 0;
xfs_lsn_t lowest_lsn;
int ioerrors; /* counter: iclogs with errors */
int loopdidcallbacks; /* flag: inner loop did callbacks*/
int funcdidcallbacks; /* flag: function did callbacks */
int repeats; /* for issuing console warnings if
* looping too many times */
int wake = 0;
spin_lock(&log->l_icloglock);
first_iclog = iclog = log->l_iclog;
ioerrors = 0;
funcdidcallbacks = 0;
repeats = 0;
do {
/*
* Scan all iclogs starting with the one pointed to by the
* log. Reset this starting point each time the log is
* unlocked (during callbacks).
*
* Keep looping through iclogs until one full pass is made
* without running any callbacks.
*/
first_iclog = log->l_iclog;
iclog = log->l_iclog;
loopdidcallbacks = 0;
repeats++;
do {
/* skip all iclogs in the ACTIVE & DIRTY states */
if (iclog->ic_state &
(XLOG_STATE_ACTIVE|XLOG_STATE_DIRTY)) {
iclog = iclog->ic_next;
continue;
}
/*
* Between marking a filesystem SHUTDOWN and stopping
* the log, we do flush all iclogs to disk (if there
* wasn't a log I/O error). So, we do want things to
* go smoothly in case of just a SHUTDOWN w/o a
* LOG_IO_ERROR.
*/
if (!(iclog->ic_state & XLOG_STATE_IOERROR)) {
/*
* Can only perform callbacks in order. Since
* this iclog is not in the DONE_SYNC/
* DO_CALLBACK state, we skip the rest and
* just try to clean up. If we set our iclog
* to DO_CALLBACK, we will not process it when
* we retry since a previous iclog is in the
* CALLBACK and the state cannot change since
* we are holding the l_icloglock.
*/
if (!(iclog->ic_state &
(XLOG_STATE_DONE_SYNC |
XLOG_STATE_DO_CALLBACK))) {
if (ciclog && (ciclog->ic_state ==
XLOG_STATE_DONE_SYNC)) {
ciclog->ic_state = XLOG_STATE_DO_CALLBACK;
}
break;
}
/*
* We now have an iclog that is in either the
* DO_CALLBACK or DONE_SYNC states. The other
* states (WANT_SYNC, SYNCING, or CALLBACK were
* caught by the above if and are going to
* clean (i.e. we aren't doing their callbacks)
* see the above if.
*/
/*
* We will do one more check here to see if we
* have chased our tail around.
*/
lowest_lsn = xlog_get_lowest_lsn(log);
if (lowest_lsn &&
XFS_LSN_CMP(lowest_lsn,
be64_to_cpu(iclog->ic_header.h_lsn)) < 0) {
iclog = iclog->ic_next;
continue; /* Leave this iclog for
* another thread */
}
iclog->ic_state = XLOG_STATE_CALLBACK;
spin_unlock(&log->l_icloglock);
/* l_last_sync_lsn field protected by
* l_grant_lock. Don't worry about iclog's lsn.
* No one else can be here except us.
*/
spin_lock(&log->l_grant_lock);
ASSERT(XFS_LSN_CMP(log->l_last_sync_lsn,
be64_to_cpu(iclog->ic_header.h_lsn)) <= 0);
log->l_last_sync_lsn =
be64_to_cpu(iclog->ic_header.h_lsn);
spin_unlock(&log->l_grant_lock);
} else {
spin_unlock(&log->l_icloglock);
ioerrors++;
}
/*
* Keep processing entries in the callback list until
* we come around and it is empty. We need to
* atomically see that the list is empty and change the
* state to DIRTY so that we don't miss any more
* callbacks being added.
*/
spin_lock(&iclog->ic_callback_lock);
cb = iclog->ic_callback;
while (cb) {
iclog->ic_callback_tail = &(iclog->ic_callback);
iclog->ic_callback = NULL;
spin_unlock(&iclog->ic_callback_lock);
/* perform callbacks in the order given */
for (; cb; cb = cb_next) {
cb_next = cb->cb_next;
cb->cb_func(cb->cb_arg, aborted);
}
spin_lock(&iclog->ic_callback_lock);
cb = iclog->ic_callback;
}
loopdidcallbacks++;
funcdidcallbacks++;
spin_lock(&log->l_icloglock);
ASSERT(iclog->ic_callback == NULL);
spin_unlock(&iclog->ic_callback_lock);
if (!(iclog->ic_state & XLOG_STATE_IOERROR))
iclog->ic_state = XLOG_STATE_DIRTY;
/*
* Transition from DIRTY to ACTIVE if applicable.
* NOP if STATE_IOERROR.
*/
xlog_state_clean_log(log);
/* wake up threads waiting in xfs_log_force() */
sv_broadcast(&iclog->ic_force_wait);
iclog = iclog->ic_next;
} while (first_iclog != iclog);
if (repeats > 5000) {
flushcnt += repeats;
repeats = 0;
xfs_fs_cmn_err(CE_WARN, log->l_mp,
"%s: possible infinite loop (%d iterations)",
__func__, flushcnt);
}
} while (!ioerrors && loopdidcallbacks);
/*
* make one last gasp attempt to see if iclogs are being left in
* limbo..
*/
#ifdef DEBUG
if (funcdidcallbacks) {
first_iclog = iclog = log->l_iclog;
do {
ASSERT(iclog->ic_state != XLOG_STATE_DO_CALLBACK);
/*
* Terminate the loop if iclogs are found in states
* which will cause other threads to clean up iclogs.
*
* SYNCING - i/o completion will go through logs
* DONE_SYNC - interrupt thread should be waiting for
* l_icloglock
* IOERROR - give up hope all ye who enter here
*/
if (iclog->ic_state == XLOG_STATE_WANT_SYNC ||
iclog->ic_state == XLOG_STATE_SYNCING ||
iclog->ic_state == XLOG_STATE_DONE_SYNC ||
iclog->ic_state == XLOG_STATE_IOERROR )
break;
iclog = iclog->ic_next;
} while (first_iclog != iclog);
}
#endif
if (log->l_iclog->ic_state & (XLOG_STATE_ACTIVE|XLOG_STATE_IOERROR))
wake = 1;
spin_unlock(&log->l_icloglock);
if (wake)
sv_broadcast(&log->l_flush_wait);
}
/*
* Finish transitioning this iclog to the dirty state.
*
* Make sure that we completely execute this routine only when this is
* the last call to the iclog. There is a good chance that iclog flushes,
* when we reach the end of the physical log, get turned into 2 separate
* calls to bwrite. Hence, one iclog flush could generate two calls to this
* routine. By using the reference count bwritecnt, we guarantee that only
* the second completion goes through.
*
* Callbacks could take time, so they are done outside the scope of the
* global state machine log lock.
*/
STATIC void
xlog_state_done_syncing(
xlog_in_core_t *iclog,
int aborted)
{
xlog_t *log = iclog->ic_log;
spin_lock(&log->l_icloglock);
ASSERT(iclog->ic_state == XLOG_STATE_SYNCING ||
iclog->ic_state == XLOG_STATE_IOERROR);
ASSERT(atomic_read(&iclog->ic_refcnt) == 0);
ASSERT(iclog->ic_bwritecnt == 1 || iclog->ic_bwritecnt == 2);
/*
* If we got an error, either on the first buffer, or in the case of
* split log writes, on the second, we mark ALL iclogs STATE_IOERROR,
* and none should ever be attempted to be written to disk
* again.
*/
if (iclog->ic_state != XLOG_STATE_IOERROR) {
if (--iclog->ic_bwritecnt == 1) {
spin_unlock(&log->l_icloglock);
return;
}
iclog->ic_state = XLOG_STATE_DONE_SYNC;
}
/*
* Someone could be sleeping prior to writing out the next
* iclog buffer, we wake them all, one will get to do the
* I/O, the others get to wait for the result.
*/
sv_broadcast(&iclog->ic_write_wait);
spin_unlock(&log->l_icloglock);
xlog_state_do_callback(log, aborted, iclog); /* also cleans log */
} /* xlog_state_done_syncing */
/*
* If the head of the in-core log ring is not (ACTIVE or DIRTY), then we must
* sleep. We wait on the flush queue on the head iclog as that should be
* the first iclog to complete flushing. Hence if all iclogs are syncing,
* we will wait here and all new writes will sleep until a sync completes.
*
* The in-core logs are used in a circular fashion. They are not used
* out-of-order even when an iclog past the head is free.
*
* return:
* * log_offset where xlog_write() can start writing into the in-core
* log's data space.
* * in-core log pointer to which xlog_write() should write.
* * boolean indicating this is a continued write to an in-core log.
* If this is the last write, then the in-core log's offset field
* needs to be incremented, depending on the amount of data which
* is copied.
*/
STATIC int
xlog_state_get_iclog_space(xlog_t *log,
int len,
xlog_in_core_t **iclogp,
xlog_ticket_t *ticket,
int *continued_write,
int *logoffsetp)
{
int log_offset;
xlog_rec_header_t *head;
xlog_in_core_t *iclog;
int error;
restart:
spin_lock(&log->l_icloglock);
if (XLOG_FORCED_SHUTDOWN(log)) {
spin_unlock(&log->l_icloglock);
return XFS_ERROR(EIO);
}
iclog = log->l_iclog;
if (iclog->ic_state != XLOG_STATE_ACTIVE) {
XFS_STATS_INC(xs_log_noiclogs);
/* Wait for log writes to have flushed */
sv_wait(&log->l_flush_wait, 0, &log->l_icloglock, 0);
goto restart;
}
head = &iclog->ic_header;
atomic_inc(&iclog->ic_refcnt); /* prevents sync */
log_offset = iclog->ic_offset;
/* On the 1st write to an iclog, figure out lsn. This works
* if iclogs marked XLOG_STATE_WANT_SYNC always write out what they are
* committing to. If the offset is set, that's how many blocks
* must be written.
*/
if (log_offset == 0) {
ticket->t_curr_res -= log->l_iclog_hsize;
xlog_tic_add_region(ticket,
log->l_iclog_hsize,
XLOG_REG_TYPE_LRHEADER);
head->h_cycle = cpu_to_be32(log->l_curr_cycle);
head->h_lsn = cpu_to_be64(
xlog_assign_lsn(log->l_curr_cycle, log->l_curr_block));
ASSERT(log->l_curr_block >= 0);
}
/* If there is enough room to write everything, then do it. Otherwise,
* claim the rest of the region and make sure the XLOG_STATE_WANT_SYNC
* bit is on, so this will get flushed out. Don't update ic_offset
* until you know exactly how many bytes get copied. Therefore, wait
* until later to update ic_offset.
*
* xlog_write() algorithm assumes that at least 2 xlog_op_header_t's
* can fit into remaining data section.
*/
if (iclog->ic_size - iclog->ic_offset < 2*sizeof(xlog_op_header_t)) {
xlog_state_switch_iclogs(log, iclog, iclog->ic_size);
/*
* If I'm the only one writing to this iclog, sync it to disk.
* We need to do an atomic compare and decrement here to avoid
* racing with concurrent atomic_dec_and_lock() calls in
* xlog_state_release_iclog() when there is more than one
* reference to the iclog.
*/
if (!atomic_add_unless(&iclog->ic_refcnt, -1, 1)) {
/* we are the only one */
spin_unlock(&log->l_icloglock);
error = xlog_state_release_iclog(log, iclog);
if (error)
return error;
} else {
spin_unlock(&log->l_icloglock);
}
goto restart;
}
/* Do we have enough room to write the full amount in the remainder
* of this iclog? Or must we continue a write on the next iclog and
* mark this iclog as completely taken? In the case where we switch
* iclogs (to mark it taken), this particular iclog will release/sync
* to disk in xlog_write().
*/
if (len <= iclog->ic_size - iclog->ic_offset) {
*continued_write = 0;
iclog->ic_offset += len;
} else {
*continued_write = 1;
xlog_state_switch_iclogs(log, iclog, iclog->ic_size);
}
*iclogp = iclog;
ASSERT(iclog->ic_offset <= iclog->ic_size);
spin_unlock(&log->l_icloglock);
*logoffsetp = log_offset;
return 0;
} /* xlog_state_get_iclog_space */
/*
* Atomically get the log space required for a log ticket.
*
* Once a ticket gets put onto the reserveq, it will only return after
* the needed reservation is satisfied.
*/
STATIC int
xlog_grant_log_space(xlog_t *log,
xlog_ticket_t *tic)
{
int free_bytes;
int need_bytes;
#ifdef DEBUG
xfs_lsn_t tail_lsn;
#endif
#ifdef DEBUG
if (log->l_flags & XLOG_ACTIVE_RECOVERY)
panic("grant Recovery problem");
#endif
/* Is there space or do we need to sleep? */
spin_lock(&log->l_grant_lock);
trace_xfs_log_grant_enter(log, tic);
/* something is already sleeping; insert new transaction at end */
if (log->l_reserve_headq) {
xlog_ins_ticketq(&log->l_reserve_headq, tic);
trace_xfs_log_grant_sleep1(log, tic);
/*
* Gotta check this before going to sleep, while we're
* holding the grant lock.
*/
if (XLOG_FORCED_SHUTDOWN(log))
goto error_return;
XFS_STATS_INC(xs_sleep_logspace);
sv_wait(&tic->t_wait, PINOD|PLTWAIT, &log->l_grant_lock, s);
/*
* If we got an error, and the filesystem is shutting down,
* we'll catch it down below. So just continue...
*/
trace_xfs_log_grant_wake1(log, tic);
spin_lock(&log->l_grant_lock);
}
if (tic->t_flags & XFS_LOG_PERM_RESERV)
need_bytes = tic->t_unit_res*tic->t_ocnt;
else
need_bytes = tic->t_unit_res;
redo:
if (XLOG_FORCED_SHUTDOWN(log))
goto error_return;
free_bytes = xlog_space_left(log, log->l_grant_reserve_cycle,
log->l_grant_reserve_bytes);
if (free_bytes < need_bytes) {
if ((tic->t_flags & XLOG_TIC_IN_Q) == 0)
xlog_ins_ticketq(&log->l_reserve_headq, tic);
trace_xfs_log_grant_sleep2(log, tic);
spin_unlock(&log->l_grant_lock);
xlog_grant_push_ail(log->l_mp, need_bytes);
spin_lock(&log->l_grant_lock);
XFS_STATS_INC(xs_sleep_logspace);
sv_wait(&tic->t_wait, PINOD|PLTWAIT, &log->l_grant_lock, s);
spin_lock(&log->l_grant_lock);
if (XLOG_FORCED_SHUTDOWN(log))
goto error_return;
trace_xfs_log_grant_wake2(log, tic);
goto redo;
} else if (tic->t_flags & XLOG_TIC_IN_Q)
xlog_del_ticketq(&log->l_reserve_headq, tic);
/* we've got enough space */
xlog_grant_add_space(log, need_bytes);
#ifdef DEBUG
tail_lsn = log->l_tail_lsn;
/*
* Check to make sure the grant write head didn't just over lap the
* tail. If the cycles are the same, we can't be overlapping.
* Otherwise, make sure that the cycles differ by exactly one and
* check the byte count.
*/
if (CYCLE_LSN(tail_lsn) != log->l_grant_write_cycle) {
ASSERT(log->l_grant_write_cycle-1 == CYCLE_LSN(tail_lsn));
ASSERT(log->l_grant_write_bytes <= BBTOB(BLOCK_LSN(tail_lsn)));
}
#endif
trace_xfs_log_grant_exit(log, tic);
xlog_verify_grant_head(log, 1);
spin_unlock(&log->l_grant_lock);
return 0;
error_return:
if (tic->t_flags & XLOG_TIC_IN_Q)
xlog_del_ticketq(&log->l_reserve_headq, tic);
trace_xfs_log_grant_error(log, tic);
/*
* If we are failing, make sure the ticket doesn't have any
* current reservations. We don't want to add this back when
* the ticket/transaction gets cancelled.
*/
tic->t_curr_res = 0;
tic->t_cnt = 0; /* ungrant will give back unit_res * t_cnt. */
spin_unlock(&log->l_grant_lock);
return XFS_ERROR(EIO);
} /* xlog_grant_log_space */
/*
* Replenish the byte reservation required by moving the grant write head.
*
*
*/
STATIC int
xlog_regrant_write_log_space(xlog_t *log,
xlog_ticket_t *tic)
{
int free_bytes, need_bytes;
xlog_ticket_t *ntic;
#ifdef DEBUG
xfs_lsn_t tail_lsn;
#endif
tic->t_curr_res = tic->t_unit_res;
xlog_tic_reset_res(tic);
if (tic->t_cnt > 0)
return 0;
#ifdef DEBUG
if (log->l_flags & XLOG_ACTIVE_RECOVERY)
panic("regrant Recovery problem");
#endif
spin_lock(&log->l_grant_lock);
trace_xfs_log_regrant_write_enter(log, tic);
if (XLOG_FORCED_SHUTDOWN(log))
goto error_return;
/* If there are other waiters on the queue then give them a
* chance at logspace before us. Wake up the first waiters,
* if we do not wake up all the waiters then go to sleep waiting
* for more free space, otherwise try to get some space for
* this transaction.
*/
need_bytes = tic->t_unit_res;
if ((ntic = log->l_write_headq)) {
free_bytes = xlog_space_left(log, log->l_grant_write_cycle,
log->l_grant_write_bytes);
do {
ASSERT(ntic->t_flags & XLOG_TIC_PERM_RESERV);
if (free_bytes < ntic->t_unit_res)
break;
free_bytes -= ntic->t_unit_res;
sv_signal(&ntic->t_wait);
ntic = ntic->t_next;
} while (ntic != log->l_write_headq);
if (ntic != log->l_write_headq) {
if ((tic->t_flags & XLOG_TIC_IN_Q) == 0)
xlog_ins_ticketq(&log->l_write_headq, tic);
trace_xfs_log_regrant_write_sleep1(log, tic);
spin_unlock(&log->l_grant_lock);
xlog_grant_push_ail(log->l_mp, need_bytes);
spin_lock(&log->l_grant_lock);
XFS_STATS_INC(xs_sleep_logspace);
sv_wait(&tic->t_wait, PINOD|PLTWAIT,
&log->l_grant_lock, s);
/* If we're shutting down, this tic is already
* off the queue */
spin_lock(&log->l_grant_lock);
if (XLOG_FORCED_SHUTDOWN(log))
goto error_return;
trace_xfs_log_regrant_write_wake1(log, tic);
}
}
redo:
if (XLOG_FORCED_SHUTDOWN(log))
goto error_return;
free_bytes = xlog_space_left(log, log->l_grant_write_cycle,
log->l_grant_write_bytes);
if (free_bytes < need_bytes) {
if ((tic->t_flags & XLOG_TIC_IN_Q) == 0)
xlog_ins_ticketq(&log->l_write_headq, tic);
spin_unlock(&log->l_grant_lock);
xlog_grant_push_ail(log->l_mp, need_bytes);
spin_lock(&log->l_grant_lock);
XFS_STATS_INC(xs_sleep_logspace);
trace_xfs_log_regrant_write_sleep2(log, tic);
sv_wait(&tic->t_wait, PINOD|PLTWAIT, &log->l_grant_lock, s);
/* If we're shutting down, this tic is already off the queue */
spin_lock(&log->l_grant_lock);
if (XLOG_FORCED_SHUTDOWN(log))
goto error_return;
trace_xfs_log_regrant_write_wake2(log, tic);
goto redo;
} else if (tic->t_flags & XLOG_TIC_IN_Q)
xlog_del_ticketq(&log->l_write_headq, tic);
/* we've got enough space */
xlog_grant_add_space_write(log, need_bytes);
#ifdef DEBUG
tail_lsn = log->l_tail_lsn;
if (CYCLE_LSN(tail_lsn) != log->l_grant_write_cycle) {
ASSERT(log->l_grant_write_cycle-1 == CYCLE_LSN(tail_lsn));
ASSERT(log->l_grant_write_bytes <= BBTOB(BLOCK_LSN(tail_lsn)));
}
#endif
trace_xfs_log_regrant_write_exit(log, tic);
xlog_verify_grant_head(log, 1);
spin_unlock(&log->l_grant_lock);
return 0;
error_return:
if (tic->t_flags & XLOG_TIC_IN_Q)
xlog_del_ticketq(&log->l_reserve_headq, tic);
trace_xfs_log_regrant_write_error(log, tic);
/*
* If we are failing, make sure the ticket doesn't have any
* current reservations. We don't want to add this back when
* the ticket/transaction gets cancelled.
*/
tic->t_curr_res = 0;
tic->t_cnt = 0; /* ungrant will give back unit_res * t_cnt. */
spin_unlock(&log->l_grant_lock);
return XFS_ERROR(EIO);
} /* xlog_regrant_write_log_space */
/* The first cnt-1 times through here we don't need to
* move the grant write head because the permanent
* reservation has reserved cnt times the unit amount.
* Release part of current permanent unit reservation and
* reset current reservation to be one units worth. Also
* move grant reservation head forward.
*/
STATIC void
xlog_regrant_reserve_log_space(xlog_t *log,
xlog_ticket_t *ticket)
{
trace_xfs_log_regrant_reserve_enter(log, ticket);
if (ticket->t_cnt > 0)
ticket->t_cnt--;
spin_lock(&log->l_grant_lock);
xlog_grant_sub_space(log, ticket->t_curr_res);
ticket->t_curr_res = ticket->t_unit_res;
xlog_tic_reset_res(ticket);
trace_xfs_log_regrant_reserve_sub(log, ticket);
xlog_verify_grant_head(log, 1);
/* just return if we still have some of the pre-reserved space */
if (ticket->t_cnt > 0) {
spin_unlock(&log->l_grant_lock);
return;
}
xlog_grant_add_space_reserve(log, ticket->t_unit_res);
trace_xfs_log_regrant_reserve_exit(log, ticket);
xlog_verify_grant_head(log, 0);
spin_unlock(&log->l_grant_lock);
ticket->t_curr_res = ticket->t_unit_res;
xlog_tic_reset_res(ticket);
} /* xlog_regrant_reserve_log_space */
/*
* Give back the space left from a reservation.
*
* All the information we need to make a correct determination of space left
* is present. For non-permanent reservations, things are quite easy. The
* count should have been decremented to zero. We only need to deal with the
* space remaining in the current reservation part of the ticket. If the
* ticket contains a permanent reservation, there may be left over space which
* needs to be released. A count of N means that N-1 refills of the current
* reservation can be done before we need to ask for more space. The first
* one goes to fill up the first current reservation. Once we run out of
* space, the count will stay at zero and the only space remaining will be
* in the current reservation field.
*/
STATIC void
xlog_ungrant_log_space(xlog_t *log,
xlog_ticket_t *ticket)
{
if (ticket->t_cnt > 0)
ticket->t_cnt--;
spin_lock(&log->l_grant_lock);
trace_xfs_log_ungrant_enter(log, ticket);
xlog_grant_sub_space(log, ticket->t_curr_res);
trace_xfs_log_ungrant_sub(log, ticket);
/* If this is a permanent reservation ticket, we may be able to free
* up more space based on the remaining count.
*/
if (ticket->t_cnt > 0) {
ASSERT(ticket->t_flags & XLOG_TIC_PERM_RESERV);
xlog_grant_sub_space(log, ticket->t_unit_res*ticket->t_cnt);
}
trace_xfs_log_ungrant_exit(log, ticket);
xlog_verify_grant_head(log, 1);
spin_unlock(&log->l_grant_lock);
xfs_log_move_tail(log->l_mp, 1);
} /* xlog_ungrant_log_space */
/*
* Flush iclog to disk if this is the last reference to the given iclog and
* the WANT_SYNC bit is set.
*
* When this function is entered, the iclog is not necessarily in the
* WANT_SYNC state. It may be sitting around waiting to get filled.
*
*
*/
STATIC int
xlog_state_release_iclog(
xlog_t *log,
xlog_in_core_t *iclog)
{
int sync = 0; /* do we sync? */
if (iclog->ic_state & XLOG_STATE_IOERROR)
return XFS_ERROR(EIO);
ASSERT(atomic_read(&iclog->ic_refcnt) > 0);
if (!atomic_dec_and_lock(&iclog->ic_refcnt, &log->l_icloglock))
return 0;
if (iclog->ic_state & XLOG_STATE_IOERROR) {
spin_unlock(&log->l_icloglock);
return XFS_ERROR(EIO);
}
ASSERT(iclog->ic_state == XLOG_STATE_ACTIVE ||
iclog->ic_state == XLOG_STATE_WANT_SYNC);
if (iclog->ic_state == XLOG_STATE_WANT_SYNC) {
/* update tail before writing to iclog */
xlog_assign_tail_lsn(log->l_mp);
sync++;
iclog->ic_state = XLOG_STATE_SYNCING;
iclog->ic_header.h_tail_lsn = cpu_to_be64(log->l_tail_lsn);
xlog_verify_tail_lsn(log, iclog, log->l_tail_lsn);
/* cycle incremented when incrementing curr_block */
}
spin_unlock(&log->l_icloglock);
/*
* We let the log lock go, so it's possible that we hit a log I/O
* error or some other SHUTDOWN condition that marks the iclog
* as XLOG_STATE_IOERROR before the bwrite. However, we know that
* this iclog has consistent data, so we ignore IOERROR
* flags after this point.
*/
if (sync)
return xlog_sync(log, iclog);
return 0;
} /* xlog_state_release_iclog */
/*
* This routine will mark the current iclog in the ring as WANT_SYNC
* and move the current iclog pointer to the next iclog in the ring.
* When this routine is called from xlog_state_get_iclog_space(), the
* exact size of the iclog has not yet been determined. All we know is
* that every data block. We have run out of space in this log record.
*/
STATIC void
xlog_state_switch_iclogs(xlog_t *log,
xlog_in_core_t *iclog,
int eventual_size)
{
ASSERT(iclog->ic_state == XLOG_STATE_ACTIVE);
if (!eventual_size)
eventual_size = iclog->ic_offset;
iclog->ic_state = XLOG_STATE_WANT_SYNC;
iclog->ic_header.h_prev_block = cpu_to_be32(log->l_prev_block);
log->l_prev_block = log->l_curr_block;
log->l_prev_cycle = log->l_curr_cycle;
/* roll log?: ic_offset changed later */
log->l_curr_block += BTOBB(eventual_size)+BTOBB(log->l_iclog_hsize);
/* Round up to next log-sunit */
if (xfs_sb_version_haslogv2(&log->l_mp->m_sb) &&
log->l_mp->m_sb.sb_logsunit > 1) {
__uint32_t sunit_bb = BTOBB(log->l_mp->m_sb.sb_logsunit);
log->l_curr_block = roundup(log->l_curr_block, sunit_bb);
}
if (log->l_curr_block >= log->l_logBBsize) {
log->l_curr_cycle++;
if (log->l_curr_cycle == XLOG_HEADER_MAGIC_NUM)
log->l_curr_cycle++;
log->l_curr_block -= log->l_logBBsize;
ASSERT(log->l_curr_block >= 0);
}
ASSERT(iclog == log->l_iclog);
log->l_iclog = iclog->ic_next;
} /* xlog_state_switch_iclogs */
/*
* Write out all data in the in-core log as of this exact moment in time.
*
* Data may be written to the in-core log during this call. However,
* we don't guarantee this data will be written out. A change from past
* implementation means this routine will *not* write out zero length LRs.
*
* Basically, we try and perform an intelligent scan of the in-core logs.
* If we determine there is no flushable data, we just return. There is no
* flushable data if:
*
* 1. the current iclog is active and has no data; the previous iclog
* is in the active or dirty state.
* 2. the current iclog is drity, and the previous iclog is in the
* active or dirty state.
*
* We may sleep if:
*
* 1. the current iclog is not in the active nor dirty state.
* 2. the current iclog dirty, and the previous iclog is not in the
* active nor dirty state.
* 3. the current iclog is active, and there is another thread writing
* to this particular iclog.
* 4. a) the current iclog is active and has no other writers
* b) when we return from flushing out this iclog, it is still
* not in the active nor dirty state.
*/
int
_xfs_log_force(
struct xfs_mount *mp,
uint flags,
int *log_flushed)
{
struct log *log = mp->m_log;
struct xlog_in_core *iclog;
xfs_lsn_t lsn;
XFS_STATS_INC(xs_log_force);
spin_lock(&log->l_icloglock);
iclog = log->l_iclog;
if (iclog->ic_state & XLOG_STATE_IOERROR) {
spin_unlock(&log->l_icloglock);
return XFS_ERROR(EIO);
}
/* If the head iclog is not active nor dirty, we just attach
* ourselves to the head and go to sleep.
*/
if (iclog->ic_state == XLOG_STATE_ACTIVE ||
iclog->ic_state == XLOG_STATE_DIRTY) {
/*
* If the head is dirty or (active and empty), then
* we need to look at the previous iclog. If the previous
* iclog is active or dirty we are done. There is nothing
* to sync out. Otherwise, we attach ourselves to the
* previous iclog and go to sleep.
*/
if (iclog->ic_state == XLOG_STATE_DIRTY ||
(atomic_read(&iclog->ic_refcnt) == 0
&& iclog->ic_offset == 0)) {
iclog = iclog->ic_prev;
if (iclog->ic_state == XLOG_STATE_ACTIVE ||
iclog->ic_state == XLOG_STATE_DIRTY)
goto no_sleep;
else
goto maybe_sleep;
} else {
if (atomic_read(&iclog->ic_refcnt) == 0) {
/* We are the only one with access to this
* iclog. Flush it out now. There should
* be a roundoff of zero to show that someone
* has already taken care of the roundoff from
* the previous sync.
*/
atomic_inc(&iclog->ic_refcnt);
lsn = be64_to_cpu(iclog->ic_header.h_lsn);
xlog_state_switch_iclogs(log, iclog, 0);
spin_unlock(&log->l_icloglock);
if (xlog_state_release_iclog(log, iclog))
return XFS_ERROR(EIO);
if (log_flushed)
*log_flushed = 1;
spin_lock(&log->l_icloglock);
if (be64_to_cpu(iclog->ic_header.h_lsn) == lsn &&
iclog->ic_state != XLOG_STATE_DIRTY)
goto maybe_sleep;
else
goto no_sleep;
} else {
/* Someone else is writing to this iclog.
* Use its call to flush out the data. However,
* the other thread may not force out this LR,
* so we mark it WANT_SYNC.
*/
xlog_state_switch_iclogs(log, iclog, 0);
goto maybe_sleep;
}
}
}
/* By the time we come around again, the iclog could've been filled
* which would give it another lsn. If we have a new lsn, just
* return because the relevant data has been flushed.
*/
maybe_sleep:
if (flags & XFS_LOG_SYNC) {
/*
* We must check if we're shutting down here, before
* we wait, while we're holding the l_icloglock.
* Then we check again after waking up, in case our
* sleep was disturbed by a bad news.
*/
if (iclog->ic_state & XLOG_STATE_IOERROR) {
spin_unlock(&log->l_icloglock);
return XFS_ERROR(EIO);
}
XFS_STATS_INC(xs_log_force_sleep);
sv_wait(&iclog->ic_force_wait, PINOD, &log->l_icloglock, s);
/*
* No need to grab the log lock here since we're
* only deciding whether or not to return EIO
* and the memory read should be atomic.
*/
if (iclog->ic_state & XLOG_STATE_IOERROR)
return XFS_ERROR(EIO);
if (log_flushed)
*log_flushed = 1;
} else {
no_sleep:
spin_unlock(&log->l_icloglock);
}
return 0;
}
/*
* Wrapper for _xfs_log_force(), to be used when caller doesn't care
* about errors or whether the log was flushed or not. This is the normal
* interface to use when trying to unpin items or move the log forward.
*/
void
xfs_log_force(
xfs_mount_t *mp,
uint flags)
{
int error;
error = _xfs_log_force(mp, flags, NULL);
if (error) {
xfs_fs_cmn_err(CE_WARN, mp, "xfs_log_force: "
"error %d returned.", error);
}
}
/*
* Force the in-core log to disk for a specific LSN.
*
* Find in-core log with lsn.
* If it is in the DIRTY state, just return.
* If it is in the ACTIVE state, move the in-core log into the WANT_SYNC
* state and go to sleep or return.
* If it is in any other state, go to sleep or return.
*
* Synchronous forces are implemented with a signal variable. All callers
* to force a given lsn to disk will wait on a the sv attached to the
* specific in-core log. When given in-core log finally completes its
* write to disk, that thread will wake up all threads waiting on the
* sv.
*/
int
_xfs_log_force_lsn(
struct xfs_mount *mp,
xfs_lsn_t lsn,
uint flags,
int *log_flushed)
{
struct log *log = mp->m_log;
struct xlog_in_core *iclog;
int already_slept = 0;
ASSERT(lsn != 0);
XFS_STATS_INC(xs_log_force);
try_again:
spin_lock(&log->l_icloglock);
iclog = log->l_iclog;
if (iclog->ic_state & XLOG_STATE_IOERROR) {
spin_unlock(&log->l_icloglock);
return XFS_ERROR(EIO);
}
do {
if (be64_to_cpu(iclog->ic_header.h_lsn) != lsn) {
iclog = iclog->ic_next;
continue;
}
if (iclog->ic_state == XLOG_STATE_DIRTY) {
spin_unlock(&log->l_icloglock);
return 0;
}
if (iclog->ic_state == XLOG_STATE_ACTIVE) {
/*
* We sleep here if we haven't already slept (e.g.
* this is the first time we've looked at the correct
* iclog buf) and the buffer before us is going to
* be sync'ed. The reason for this is that if we
* are doing sync transactions here, by waiting for
* the previous I/O to complete, we can allow a few
* more transactions into this iclog before we close
* it down.
*
* Otherwise, we mark the buffer WANT_SYNC, and bump
* up the refcnt so we can release the log (which
* drops the ref count). The state switch keeps new
* transaction commits from using this buffer. When
* the current commits finish writing into the buffer,
* the refcount will drop to zero and the buffer will
* go out then.
*/
if (!already_slept &&
(iclog->ic_prev->ic_state &
(XLOG_STATE_WANT_SYNC | XLOG_STATE_SYNCING))) {
ASSERT(!(iclog->ic_state & XLOG_STATE_IOERROR));
XFS_STATS_INC(xs_log_force_sleep);
sv_wait(&iclog->ic_prev->ic_write_wait,
PSWP, &log->l_icloglock, s);
if (log_flushed)
*log_flushed = 1;
already_slept = 1;
goto try_again;
}
atomic_inc(&iclog->ic_refcnt);
xlog_state_switch_iclogs(log, iclog, 0);
spin_unlock(&log->l_icloglock);
if (xlog_state_release_iclog(log, iclog))
return XFS_ERROR(EIO);
if (log_flushed)
*log_flushed = 1;
spin_lock(&log->l_icloglock);
}
if ((flags & XFS_LOG_SYNC) && /* sleep */
!(iclog->ic_state &
(XLOG_STATE_ACTIVE | XLOG_STATE_DIRTY))) {
/*
* Don't wait on completion if we know that we've
* gotten a log write error.
*/
if (iclog->ic_state & XLOG_STATE_IOERROR) {
spin_unlock(&log->l_icloglock);
return XFS_ERROR(EIO);
}
XFS_STATS_INC(xs_log_force_sleep);
sv_wait(&iclog->ic_force_wait, PSWP, &log->l_icloglock, s);
/*
* No need to grab the log lock here since we're
* only deciding whether or not to return EIO
* and the memory read should be atomic.
*/
if (iclog->ic_state & XLOG_STATE_IOERROR)
return XFS_ERROR(EIO);
if (log_flushed)
*log_flushed = 1;
} else { /* just return */
spin_unlock(&log->l_icloglock);
}
return 0;
} while (iclog != log->l_iclog);
spin_unlock(&log->l_icloglock);
return 0;
}
/*
* Wrapper for _xfs_log_force_lsn(), to be used when caller doesn't care
* about errors or whether the log was flushed or not. This is the normal
* interface to use when trying to unpin items or move the log forward.
*/
void
xfs_log_force_lsn(
xfs_mount_t *mp,
xfs_lsn_t lsn,
uint flags)
{
int error;
error = _xfs_log_force_lsn(mp, lsn, flags, NULL);
if (error) {
xfs_fs_cmn_err(CE_WARN, mp, "xfs_log_force: "
"error %d returned.", error);
}
}
/*
* Called when we want to mark the current iclog as being ready to sync to
* disk.
*/
STATIC void
xlog_state_want_sync(xlog_t *log, xlog_in_core_t *iclog)
{
assert_spin_locked(&log->l_icloglock);
if (iclog->ic_state == XLOG_STATE_ACTIVE) {
xlog_state_switch_iclogs(log, iclog, 0);
} else {
ASSERT(iclog->ic_state &
(XLOG_STATE_WANT_SYNC|XLOG_STATE_IOERROR));
}
}
/*****************************************************************************
*
* TICKET functions
*
*****************************************************************************
*/
/*
* Free a used ticket when its refcount falls to zero.
*/
void
xfs_log_ticket_put(
xlog_ticket_t *ticket)
{
ASSERT(atomic_read(&ticket->t_ref) > 0);
if (atomic_dec_and_test(&ticket->t_ref)) {
sv_destroy(&ticket->t_wait);
kmem_zone_free(xfs_log_ticket_zone, ticket);
}
}
xlog_ticket_t *
xfs_log_ticket_get(
xlog_ticket_t *ticket)
{
ASSERT(atomic_read(&ticket->t_ref) > 0);
atomic_inc(&ticket->t_ref);
return ticket;
}
/*
* Allocate and initialise a new log ticket.
*/
STATIC xlog_ticket_t *
xlog_ticket_alloc(
struct log *log,
int unit_bytes,
int cnt,
char client,
uint xflags)
{
struct xlog_ticket *tic;
uint num_headers;
int iclog_space;
tic = kmem_zone_zalloc(xfs_log_ticket_zone, KM_SLEEP|KM_MAYFAIL);
if (!tic)
return NULL;
/*
* Permanent reservations have up to 'cnt'-1 active log operations
* in the log. A unit in this case is the amount of space for one
* of these log operations. Normal reservations have a cnt of 1
* and their unit amount is the total amount of space required.
*
* The following lines of code account for non-transaction data
* which occupy space in the on-disk log.
*
* Normal form of a transaction is:
* <oph><trans-hdr><start-oph><reg1-oph><reg1><reg2-oph>...<commit-oph>
* and then there are LR hdrs, split-recs and roundoff at end of syncs.
*
* We need to account for all the leadup data and trailer data
* around the transaction data.
* And then we need to account for the worst case in terms of using
* more space.
* The worst case will happen if:
* - the placement of the transaction happens to be such that the
* roundoff is at its maximum
* - the transaction data is synced before the commit record is synced
* i.e. <transaction-data><roundoff> | <commit-rec><roundoff>
* Therefore the commit record is in its own Log Record.
* This can happen as the commit record is called with its
* own region to xlog_write().
* This then means that in the worst case, roundoff can happen for
* the commit-rec as well.
* The commit-rec is smaller than padding in this scenario and so it is
* not added separately.
*/
/* for trans header */
unit_bytes += sizeof(xlog_op_header_t);
unit_bytes += sizeof(xfs_trans_header_t);
/* for start-rec */
unit_bytes += sizeof(xlog_op_header_t);
/*
* for LR headers - the space for data in an iclog is the size minus
* the space used for the headers. If we use the iclog size, then we
* undercalculate the number of headers required.
*
* Furthermore - the addition of op headers for split-recs might
* increase the space required enough to require more log and op
* headers, so take that into account too.
*
* IMPORTANT: This reservation makes the assumption that if this
* transaction is the first in an iclog and hence has the LR headers
* accounted to it, then the remaining space in the iclog is
* exclusively for this transaction. i.e. if the transaction is larger
* than the iclog, it will be the only thing in that iclog.
* Fundamentally, this means we must pass the entire log vector to
* xlog_write to guarantee this.
*/
iclog_space = log->l_iclog_size - log->l_iclog_hsize;
num_headers = howmany(unit_bytes, iclog_space);
/* for split-recs - ophdrs added when data split over LRs */
unit_bytes += sizeof(xlog_op_header_t) * num_headers;
/* add extra header reservations if we overrun */
while (!num_headers ||
howmany(unit_bytes, iclog_space) > num_headers) {
unit_bytes += sizeof(xlog_op_header_t);
num_headers++;
}
unit_bytes += log->l_iclog_hsize * num_headers;
/* for commit-rec LR header - note: padding will subsume the ophdr */
unit_bytes += log->l_iclog_hsize;
/* for roundoff padding for transaction data and one for commit record */
if (xfs_sb_version_haslogv2(&log->l_mp->m_sb) &&
log->l_mp->m_sb.sb_logsunit > 1) {
/* log su roundoff */
unit_bytes += 2*log->l_mp->m_sb.sb_logsunit;
} else {
/* BB roundoff */
unit_bytes += 2*BBSIZE;
}
atomic_set(&tic->t_ref, 1);
tic->t_unit_res = unit_bytes;
tic->t_curr_res = unit_bytes;
tic->t_cnt = cnt;
tic->t_ocnt = cnt;
tic->t_tid = (xlog_tid_t)((__psint_t)tic & 0xffffffff);
tic->t_clientid = client;
tic->t_flags = XLOG_TIC_INITED;
tic->t_trans_type = 0;
if (xflags & XFS_LOG_PERM_RESERV)
tic->t_flags |= XLOG_TIC_PERM_RESERV;
sv_init(&tic->t_wait, SV_DEFAULT, "logtick");
xlog_tic_reset_res(tic);
return tic;
}
/******************************************************************************
*
* Log debug routines
*
******************************************************************************
*/
#if defined(DEBUG)
/*
* Make sure that the destination ptr is within the valid data region of
* one of the iclogs. This uses backup pointers stored in a different
* part of the log in case we trash the log structure.
*/
void
xlog_verify_dest_ptr(xlog_t *log,
__psint_t ptr)
{
int i;
int good_ptr = 0;
for (i=0; i < log->l_iclog_bufs; i++) {
if (ptr >= (__psint_t)log->l_iclog_bak[i] &&
ptr <= (__psint_t)log->l_iclog_bak[i]+log->l_iclog_size)
good_ptr++;
}
if (! good_ptr)
xlog_panic("xlog_verify_dest_ptr: invalid ptr");
} /* xlog_verify_dest_ptr */
STATIC void
xlog_verify_grant_head(xlog_t *log, int equals)
{
if (log->l_grant_reserve_cycle == log->l_grant_write_cycle) {
if (equals)
ASSERT(log->l_grant_reserve_bytes >= log->l_grant_write_bytes);
else
ASSERT(log->l_grant_reserve_bytes > log->l_grant_write_bytes);
} else {
ASSERT(log->l_grant_reserve_cycle-1 == log->l_grant_write_cycle);
ASSERT(log->l_grant_write_bytes >= log->l_grant_reserve_bytes);
}
} /* xlog_verify_grant_head */
/* check if it will fit */
STATIC void
xlog_verify_tail_lsn(xlog_t *log,
xlog_in_core_t *iclog,
xfs_lsn_t tail_lsn)
{
int blocks;
if (CYCLE_LSN(tail_lsn) == log->l_prev_cycle) {
blocks =
log->l_logBBsize - (log->l_prev_block - BLOCK_LSN(tail_lsn));
if (blocks < BTOBB(iclog->ic_offset)+BTOBB(log->l_iclog_hsize))
xlog_panic("xlog_verify_tail_lsn: ran out of log space");
} else {
ASSERT(CYCLE_LSN(tail_lsn)+1 == log->l_prev_cycle);
if (BLOCK_LSN(tail_lsn) == log->l_prev_block)
xlog_panic("xlog_verify_tail_lsn: tail wrapped");
blocks = BLOCK_LSN(tail_lsn) - log->l_prev_block;
if (blocks < BTOBB(iclog->ic_offset) + 1)
xlog_panic("xlog_verify_tail_lsn: ran out of log space");
}
} /* xlog_verify_tail_lsn */
/*
* Perform a number of checks on the iclog before writing to disk.
*
* 1. Make sure the iclogs are still circular
* 2. Make sure we have a good magic number
* 3. Make sure we don't have magic numbers in the data
* 4. Check fields of each log operation header for:
* A. Valid client identifier
* B. tid ptr value falls in valid ptr space (user space code)
* C. Length in log record header is correct according to the
* individual operation headers within record.
* 5. When a bwrite will occur within 5 blocks of the front of the physical
* log, check the preceding blocks of the physical log to make sure all
* the cycle numbers agree with the current cycle number.
*/
STATIC void
xlog_verify_iclog(xlog_t *log,
xlog_in_core_t *iclog,
int count,
boolean_t syncing)
{
xlog_op_header_t *ophead;
xlog_in_core_t *icptr;
xlog_in_core_2_t *xhdr;
xfs_caddr_t ptr;
xfs_caddr_t base_ptr;
__psint_t field_offset;
__uint8_t clientid;
int len, i, j, k, op_len;
int idx;
/* check validity of iclog pointers */
spin_lock(&log->l_icloglock);
icptr = log->l_iclog;
for (i=0; i < log->l_iclog_bufs; i++) {
if (icptr == NULL)
xlog_panic("xlog_verify_iclog: invalid ptr");
icptr = icptr->ic_next;
}
if (icptr != log->l_iclog)
xlog_panic("xlog_verify_iclog: corrupt iclog ring");
spin_unlock(&log->l_icloglock);
/* check log magic numbers */
if (be32_to_cpu(iclog->ic_header.h_magicno) != XLOG_HEADER_MAGIC_NUM)
xlog_panic("xlog_verify_iclog: invalid magic num");
ptr = (xfs_caddr_t) &iclog->ic_header;
for (ptr += BBSIZE; ptr < ((xfs_caddr_t)&iclog->ic_header) + count;
ptr += BBSIZE) {
if (be32_to_cpu(*(__be32 *)ptr) == XLOG_HEADER_MAGIC_NUM)
xlog_panic("xlog_verify_iclog: unexpected magic num");
}
/* check fields */
len = be32_to_cpu(iclog->ic_header.h_num_logops);
ptr = iclog->ic_datap;
base_ptr = ptr;
ophead = (xlog_op_header_t *)ptr;
xhdr = iclog->ic_data;
for (i = 0; i < len; i++) {
ophead = (xlog_op_header_t *)ptr;
/* clientid is only 1 byte */
field_offset = (__psint_t)
((xfs_caddr_t)&(ophead->oh_clientid) - base_ptr);
if (syncing == B_FALSE || (field_offset & 0x1ff)) {
clientid = ophead->oh_clientid;
} else {
idx = BTOBBT((xfs_caddr_t)&(ophead->oh_clientid) - iclog->ic_datap);
if (idx >= (XLOG_HEADER_CYCLE_SIZE / BBSIZE)) {
j = idx / (XLOG_HEADER_CYCLE_SIZE / BBSIZE);
k = idx % (XLOG_HEADER_CYCLE_SIZE / BBSIZE);
clientid = xlog_get_client_id(
xhdr[j].hic_xheader.xh_cycle_data[k]);
} else {
clientid = xlog_get_client_id(
iclog->ic_header.h_cycle_data[idx]);
}
}
if (clientid != XFS_TRANSACTION && clientid != XFS_LOG)
cmn_err(CE_WARN, "xlog_verify_iclog: "
"invalid clientid %d op 0x%p offset 0x%lx",
clientid, ophead, (unsigned long)field_offset);
/* check length */
field_offset = (__psint_t)
((xfs_caddr_t)&(ophead->oh_len) - base_ptr);
if (syncing == B_FALSE || (field_offset & 0x1ff)) {
op_len = be32_to_cpu(ophead->oh_len);
} else {
idx = BTOBBT((__psint_t)&ophead->oh_len -
(__psint_t)iclog->ic_datap);
if (idx >= (XLOG_HEADER_CYCLE_SIZE / BBSIZE)) {
j = idx / (XLOG_HEADER_CYCLE_SIZE / BBSIZE);
k = idx % (XLOG_HEADER_CYCLE_SIZE / BBSIZE);
op_len = be32_to_cpu(xhdr[j].hic_xheader.xh_cycle_data[k]);
} else {
op_len = be32_to_cpu(iclog->ic_header.h_cycle_data[idx]);
}
}
ptr += sizeof(xlog_op_header_t) + op_len;
}
} /* xlog_verify_iclog */
#endif
/*
* Mark all iclogs IOERROR. l_icloglock is held by the caller.
*/
STATIC int
xlog_state_ioerror(
xlog_t *log)
{
xlog_in_core_t *iclog, *ic;
iclog = log->l_iclog;
if (! (iclog->ic_state & XLOG_STATE_IOERROR)) {
/*
* Mark all the incore logs IOERROR.
* From now on, no log flushes will result.
*/
ic = iclog;
do {
ic->ic_state = XLOG_STATE_IOERROR;
ic = ic->ic_next;
} while (ic != iclog);
return 0;
}
/*
* Return non-zero, if state transition has already happened.
*/
return 1;
}
/*
* This is called from xfs_force_shutdown, when we're forcibly
* shutting down the filesystem, typically because of an IO error.
* Our main objectives here are to make sure that:
* a. the filesystem gets marked 'SHUTDOWN' for all interested
* parties to find out, 'atomically'.
* b. those who're sleeping on log reservations, pinned objects and
* other resources get woken up, and be told the bad news.
* c. nothing new gets queued up after (a) and (b) are done.
* d. if !logerror, flush the iclogs to disk, then seal them off
* for business.
*/
int
xfs_log_force_umount(
struct xfs_mount *mp,
int logerror)
{
xlog_ticket_t *tic;
xlog_t *log;
int retval;
log = mp->m_log;
/*
* If this happens during log recovery, don't worry about
* locking; the log isn't open for business yet.
*/
if (!log ||
log->l_flags & XLOG_ACTIVE_RECOVERY) {
mp->m_flags |= XFS_MOUNT_FS_SHUTDOWN;
if (mp->m_sb_bp)
XFS_BUF_DONE(mp->m_sb_bp);
return 0;
}
/*
* Somebody could've already done the hard work for us.
* No need to get locks for this.
*/
if (logerror && log->l_iclog->ic_state & XLOG_STATE_IOERROR) {
ASSERT(XLOG_FORCED_SHUTDOWN(log));
return 1;
}
retval = 0;
/*
* We must hold both the GRANT lock and the LOG lock,
* before we mark the filesystem SHUTDOWN and wake
* everybody up to tell the bad news.
*/
spin_lock(&log->l_icloglock);
spin_lock(&log->l_grant_lock);
mp->m_flags |= XFS_MOUNT_FS_SHUTDOWN;
if (mp->m_sb_bp)
XFS_BUF_DONE(mp->m_sb_bp);
/*
* This flag is sort of redundant because of the mount flag, but
* it's good to maintain the separation between the log and the rest
* of XFS.
*/
log->l_flags |= XLOG_IO_ERROR;
/*
* If we hit a log error, we want to mark all the iclogs IOERROR
* while we're still holding the loglock.
*/
if (logerror)
retval = xlog_state_ioerror(log);
spin_unlock(&log->l_icloglock);
/*
* We don't want anybody waiting for log reservations
* after this. That means we have to wake up everybody
* queued up on reserve_headq as well as write_headq.
* In addition, we make sure in xlog_{re}grant_log_space
* that we don't enqueue anything once the SHUTDOWN flag
* is set, and this action is protected by the GRANTLOCK.
*/
if ((tic = log->l_reserve_headq)) {
do {
sv_signal(&tic->t_wait);
tic = tic->t_next;
} while (tic != log->l_reserve_headq);
}
if ((tic = log->l_write_headq)) {
do {
sv_signal(&tic->t_wait);
tic = tic->t_next;
} while (tic != log->l_write_headq);
}
spin_unlock(&log->l_grant_lock);
if (!(log->l_iclog->ic_state & XLOG_STATE_IOERROR)) {
ASSERT(!logerror);
/*
* Force the incore logs to disk before shutting the
* log down completely.
*/
_xfs_log_force(mp, XFS_LOG_SYNC, NULL);
spin_lock(&log->l_icloglock);
retval = xlog_state_ioerror(log);
spin_unlock(&log->l_icloglock);
}
/*
* Wake up everybody waiting on xfs_log_force.
* Callback all log item committed functions as if the
* log writes were completed.
*/
xlog_state_do_callback(log, XFS_LI_ABORTED, NULL);
#ifdef XFSERRORDEBUG
{
xlog_in_core_t *iclog;
spin_lock(&log->l_icloglock);
iclog = log->l_iclog;
do {
ASSERT(iclog->ic_callback == 0);
iclog = iclog->ic_next;
} while (iclog != log->l_iclog);
spin_unlock(&log->l_icloglock);
}
#endif
/* return non-zero if log IOERROR transition had already happened */
return retval;
}
STATIC int
xlog_iclogs_empty(xlog_t *log)
{
xlog_in_core_t *iclog;
iclog = log->l_iclog;
do {
/* endianness does not matter here, zero is zero in
* any language.
*/
if (iclog->ic_header.h_num_logops)
return 0;
iclog = iclog->ic_next;
} while (iclog != log->l_iclog);
return 1;
}
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