diff options
Diffstat (limited to 'fs/xfs/xfs_log.c')
| -rw-r--r-- | fs/xfs/xfs_log.c | 3907 |
1 files changed, 3907 insertions, 0 deletions
diff --git a/fs/xfs/xfs_log.c b/fs/xfs/xfs_log.c new file mode 100644 index 000000000..f02a0dd52 --- /dev/null +++ b/fs/xfs/xfs_log.c @@ -0,0 +1,3907 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (c) 2000-2005 Silicon Graphics, Inc. + * All Rights Reserved. + */ +#include "xfs.h" +#include "xfs_fs.h" +#include "xfs_shared.h" +#include "xfs_format.h" +#include "xfs_log_format.h" +#include "xfs_trans_resv.h" +#include "xfs_mount.h" +#include "xfs_errortag.h" +#include "xfs_error.h" +#include "xfs_trans.h" +#include "xfs_trans_priv.h" +#include "xfs_log.h" +#include "xfs_log_priv.h" +#include "xfs_trace.h" +#include "xfs_sysfs.h" +#include "xfs_sb.h" +#include "xfs_health.h" + +struct kmem_cache *xfs_log_ticket_cache; + +/* Local miscellaneous function prototypes */ +STATIC struct xlog * +xlog_alloc_log( + struct xfs_mount *mp, + struct xfs_buftarg *log_target, + xfs_daddr_t blk_offset, + int num_bblks); +STATIC int +xlog_space_left( + struct xlog *log, + atomic64_t *head); +STATIC void +xlog_dealloc_log( + struct xlog *log); + +/* local state machine functions */ +STATIC void xlog_state_done_syncing( + struct xlog_in_core *iclog); +STATIC void xlog_state_do_callback( + struct xlog *log); +STATIC int +xlog_state_get_iclog_space( + struct xlog *log, + int len, + struct xlog_in_core **iclog, + struct xlog_ticket *ticket, + int *logoffsetp); +STATIC void +xlog_grant_push_ail( + struct xlog *log, + int need_bytes); +STATIC void +xlog_sync( + struct xlog *log, + struct xlog_in_core *iclog, + struct xlog_ticket *ticket); +#if defined(DEBUG) +STATIC void +xlog_verify_grant_tail( + struct xlog *log); +STATIC void +xlog_verify_iclog( + struct xlog *log, + struct xlog_in_core *iclog, + int count); +STATIC void +xlog_verify_tail_lsn( + struct xlog *log, + struct xlog_in_core *iclog); +#else +#define xlog_verify_grant_tail(a) +#define xlog_verify_iclog(a,b,c) +#define xlog_verify_tail_lsn(a,b) +#endif + +STATIC int +xlog_iclogs_empty( + struct xlog *log); + +static int +xfs_log_cover(struct xfs_mount *); + +/* + * We need to make sure the buffer pointer returned is naturally aligned for the + * biggest basic data type we put into it. We have already accounted for this + * padding when sizing the buffer. + * + * However, this padding does not get written into the log, and hence we have to + * track the space used by the log vectors separately to prevent log space hangs + * due to inaccurate accounting (i.e. a leak) of the used log space through the + * CIL context ticket. + * + * We also add space for the xlog_op_header that describes this region in the + * log. This prepends the data region we return to the caller to copy their data + * into, so do all the static initialisation of the ophdr now. Because the ophdr + * is not 8 byte aligned, we have to be careful to ensure that we align the + * start of the buffer such that the region we return to the call is 8 byte + * aligned and packed against the tail of the ophdr. + */ +void * +xlog_prepare_iovec( + struct xfs_log_vec *lv, + struct xfs_log_iovec **vecp, + uint type) +{ + struct xfs_log_iovec *vec = *vecp; + struct xlog_op_header *oph; + uint32_t len; + void *buf; + + if (vec) { + ASSERT(vec - lv->lv_iovecp < lv->lv_niovecs); + vec++; + } else { + vec = &lv->lv_iovecp[0]; + } + + len = lv->lv_buf_len + sizeof(struct xlog_op_header); + if (!IS_ALIGNED(len, sizeof(uint64_t))) { + lv->lv_buf_len = round_up(len, sizeof(uint64_t)) - + sizeof(struct xlog_op_header); + } + + vec->i_type = type; + vec->i_addr = lv->lv_buf + lv->lv_buf_len; + + oph = vec->i_addr; + oph->oh_clientid = XFS_TRANSACTION; + oph->oh_res2 = 0; + oph->oh_flags = 0; + + buf = vec->i_addr + sizeof(struct xlog_op_header); + ASSERT(IS_ALIGNED((unsigned long)buf, sizeof(uint64_t))); + + *vecp = vec; + return buf; +} + +static void +xlog_grant_sub_space( + struct xlog *log, + atomic64_t *head, + int bytes) +{ + int64_t head_val = atomic64_read(head); + int64_t new, old; + + do { + int cycle, space; + + xlog_crack_grant_head_val(head_val, &cycle, &space); + + space -= bytes; + if (space < 0) { + space += log->l_logsize; + cycle--; + } + + old = head_val; + new = xlog_assign_grant_head_val(cycle, space); + head_val = atomic64_cmpxchg(head, old, new); + } while (head_val != old); +} + +static void +xlog_grant_add_space( + struct xlog *log, + atomic64_t *head, + int bytes) +{ + int64_t head_val = atomic64_read(head); + int64_t new, old; + + do { + int tmp; + int cycle, space; + + xlog_crack_grant_head_val(head_val, &cycle, &space); + + tmp = log->l_logsize - space; + if (tmp > bytes) + space += bytes; + else { + space = bytes - tmp; + cycle++; + } + + old = head_val; + new = xlog_assign_grant_head_val(cycle, space); + head_val = atomic64_cmpxchg(head, old, new); + } while (head_val != old); +} + +STATIC void +xlog_grant_head_init( + struct xlog_grant_head *head) +{ + xlog_assign_grant_head(&head->grant, 1, 0); + INIT_LIST_HEAD(&head->waiters); + spin_lock_init(&head->lock); +} + +STATIC void +xlog_grant_head_wake_all( + struct xlog_grant_head *head) +{ + struct xlog_ticket *tic; + + spin_lock(&head->lock); + list_for_each_entry(tic, &head->waiters, t_queue) + wake_up_process(tic->t_task); + spin_unlock(&head->lock); +} + +static inline int +xlog_ticket_reservation( + struct xlog *log, + struct xlog_grant_head *head, + struct xlog_ticket *tic) +{ + if (head == &log->l_write_head) { + ASSERT(tic->t_flags & XLOG_TIC_PERM_RESERV); + return tic->t_unit_res; + } + + if (tic->t_flags & XLOG_TIC_PERM_RESERV) + return tic->t_unit_res * tic->t_cnt; + + return tic->t_unit_res; +} + +STATIC bool +xlog_grant_head_wake( + struct xlog *log, + struct xlog_grant_head *head, + int *free_bytes) +{ + struct xlog_ticket *tic; + int need_bytes; + bool woken_task = false; + + list_for_each_entry(tic, &head->waiters, t_queue) { + + /* + * There is a chance that the size of the CIL checkpoints in + * progress at the last AIL push target calculation resulted in + * limiting the target to the log head (l_last_sync_lsn) at the + * time. This may not reflect where the log head is now as the + * CIL checkpoints may have completed. + * + * Hence when we are woken here, it may be that the head of the + * log that has moved rather than the tail. As the tail didn't + * move, there still won't be space available for the + * reservation we require. However, if the AIL has already + * pushed to the target defined by the old log head location, we + * will hang here waiting for something else to update the AIL + * push target. + * + * Therefore, if there isn't space to wake the first waiter on + * the grant head, we need to push the AIL again to ensure the + * target reflects both the current log tail and log head + * position before we wait for the tail to move again. + */ + + need_bytes = xlog_ticket_reservation(log, head, tic); + if (*free_bytes < need_bytes) { + if (!woken_task) + xlog_grant_push_ail(log, need_bytes); + return false; + } + + *free_bytes -= need_bytes; + trace_xfs_log_grant_wake_up(log, tic); + wake_up_process(tic->t_task); + woken_task = true; + } + + return true; +} + +STATIC int +xlog_grant_head_wait( + struct xlog *log, + struct xlog_grant_head *head, + struct xlog_ticket *tic, + int need_bytes) __releases(&head->lock) + __acquires(&head->lock) +{ + list_add_tail(&tic->t_queue, &head->waiters); + + do { + if (xlog_is_shutdown(log)) + goto shutdown; + xlog_grant_push_ail(log, need_bytes); + + __set_current_state(TASK_UNINTERRUPTIBLE); + spin_unlock(&head->lock); + + XFS_STATS_INC(log->l_mp, xs_sleep_logspace); + + trace_xfs_log_grant_sleep(log, tic); + schedule(); + trace_xfs_log_grant_wake(log, tic); + + spin_lock(&head->lock); + if (xlog_is_shutdown(log)) + goto shutdown; + } while (xlog_space_left(log, &head->grant) < need_bytes); + + list_del_init(&tic->t_queue); + return 0; +shutdown: + list_del_init(&tic->t_queue); + return -EIO; +} + +/* + * Atomically get the log space required for a log ticket. + * + * Once a ticket gets put onto head->waiters, it will only return after the + * needed reservation is satisfied. + * + * This function is structured so that it has a lock free fast path. This is + * necessary because every new transaction reservation will come through this + * path. Hence any lock will be globally hot if we take it unconditionally on + * every pass. + * + * As tickets are only ever moved on and off head->waiters under head->lock, we + * only need to take that lock if we are going to add the ticket to the queue + * and sleep. We can avoid taking the lock if the ticket was never added to + * head->waiters because the t_queue list head will be empty and we hold the + * only reference to it so it can safely be checked unlocked. + */ +STATIC int +xlog_grant_head_check( + struct xlog *log, + struct xlog_grant_head *head, + struct xlog_ticket *tic, + int *need_bytes) +{ + int free_bytes; + int error = 0; + + ASSERT(!xlog_in_recovery(log)); + + /* + * 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 = xlog_ticket_reservation(log, head, tic); + free_bytes = xlog_space_left(log, &head->grant); + if (!list_empty_careful(&head->waiters)) { + spin_lock(&head->lock); + if (!xlog_grant_head_wake(log, head, &free_bytes) || + free_bytes < *need_bytes) { + error = xlog_grant_head_wait(log, head, tic, + *need_bytes); + } + spin_unlock(&head->lock); + } else if (free_bytes < *need_bytes) { + spin_lock(&head->lock); + error = xlog_grant_head_wait(log, head, tic, *need_bytes); + spin_unlock(&head->lock); + } + + return error; +} + +bool +xfs_log_writable( + struct xfs_mount *mp) +{ + /* + * Do not write to the log on norecovery mounts, if the data or log + * devices are read-only, or if the filesystem is shutdown. Read-only + * mounts allow internal writes for log recovery and unmount purposes, + * so don't restrict that case. + */ + if (xfs_has_norecovery(mp)) + return false; + if (xfs_readonly_buftarg(mp->m_ddev_targp)) + return false; + if (xfs_readonly_buftarg(mp->m_log->l_targ)) + return false; + if (xlog_is_shutdown(mp->m_log)) + return false; + return true; +} + +/* + * Replenish the byte reservation required by moving the grant write head. + */ +int +xfs_log_regrant( + struct xfs_mount *mp, + struct xlog_ticket *tic) +{ + struct xlog *log = mp->m_log; + int need_bytes; + int error = 0; + + if (xlog_is_shutdown(log)) + return -EIO; + + XFS_STATS_INC(mp, xs_try_logspace); + + /* + * This is a new transaction on the ticket, so we need to change the + * transaction ID so that the next transaction has a different TID in + * the log. Just add one to the existing tid so that we can see chains + * of rolling transactions in the log easily. + */ + tic->t_tid++; + + xlog_grant_push_ail(log, tic->t_unit_res); + + tic->t_curr_res = tic->t_unit_res; + if (tic->t_cnt > 0) + return 0; + + trace_xfs_log_regrant(log, tic); + + error = xlog_grant_head_check(log, &log->l_write_head, tic, + &need_bytes); + if (error) + goto out_error; + + xlog_grant_add_space(log, &log->l_write_head.grant, need_bytes); + trace_xfs_log_regrant_exit(log, tic); + xlog_verify_grant_tail(log); + return 0; + +out_error: + /* + * 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. */ + return error; +} + +/* + * Reserve log space and return a ticket corresponding to the reservation. + * + * 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 **ticp, + bool permanent) +{ + struct xlog *log = mp->m_log; + struct xlog_ticket *tic; + int need_bytes; + int error = 0; + + if (xlog_is_shutdown(log)) + return -EIO; + + XFS_STATS_INC(mp, xs_try_logspace); + + ASSERT(*ticp == NULL); + tic = xlog_ticket_alloc(log, unit_bytes, cnt, permanent); + *ticp = tic; + + xlog_grant_push_ail(log, tic->t_cnt ? tic->t_unit_res * tic->t_cnt + : tic->t_unit_res); + + trace_xfs_log_reserve(log, tic); + + error = xlog_grant_head_check(log, &log->l_reserve_head, tic, + &need_bytes); + if (error) + goto out_error; + + xlog_grant_add_space(log, &log->l_reserve_head.grant, need_bytes); + xlog_grant_add_space(log, &log->l_write_head.grant, need_bytes); + trace_xfs_log_reserve_exit(log, tic); + xlog_verify_grant_tail(log); + return 0; + +out_error: + /* + * 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. */ + return error; +} + +/* + * Run all the pending iclog callbacks and wake log force waiters and iclog + * space waiters so they can process the newly set shutdown state. We really + * don't care what order we process callbacks here because the log is shut down + * and so state cannot change on disk anymore. However, we cannot wake waiters + * until the callbacks have been processed because we may be in unmount and + * we must ensure that all AIL operations the callbacks perform have completed + * before we tear down the AIL. + * + * We avoid processing actively referenced iclogs so that we don't run callbacks + * while the iclog owner might still be preparing the iclog for IO submssion. + * These will be caught by xlog_state_iclog_release() and call this function + * again to process any callbacks that may have been added to that iclog. + */ +static void +xlog_state_shutdown_callbacks( + struct xlog *log) +{ + struct xlog_in_core *iclog; + LIST_HEAD(cb_list); + + iclog = log->l_iclog; + do { + if (atomic_read(&iclog->ic_refcnt)) { + /* Reference holder will re-run iclog callbacks. */ + continue; + } + list_splice_init(&iclog->ic_callbacks, &cb_list); + spin_unlock(&log->l_icloglock); + + xlog_cil_process_committed(&cb_list); + + spin_lock(&log->l_icloglock); + wake_up_all(&iclog->ic_write_wait); + wake_up_all(&iclog->ic_force_wait); + } while ((iclog = iclog->ic_next) != log->l_iclog); + + wake_up_all(&log->l_flush_wait); +} + +/* + * Flush iclog to disk if this is the last reference to the given iclog and the + * it is in the WANT_SYNC state. + * + * If XLOG_ICL_NEED_FUA is already set on the iclog, we need to ensure that the + * log tail is updated correctly. NEED_FUA indicates that the iclog will be + * written to stable storage, and implies that a commit record is contained + * within the iclog. We need to ensure that the log tail does not move beyond + * the tail that the first commit record in the iclog ordered against, otherwise + * correct recovery of that checkpoint becomes dependent on future operations + * performed on this iclog. + * + * Hence if NEED_FUA is set and the current iclog tail lsn is empty, write the + * current tail into iclog. Once the iclog tail is set, future operations must + * not modify it, otherwise they potentially violate ordering constraints for + * the checkpoint commit that wrote the initial tail lsn value. The tail lsn in + * the iclog will get zeroed on activation of the iclog after sync, so we + * always capture the tail lsn on the iclog on the first NEED_FUA release + * regardless of the number of active reference counts on this iclog. + */ +int +xlog_state_release_iclog( + struct xlog *log, + struct xlog_in_core *iclog, + struct xlog_ticket *ticket) +{ + xfs_lsn_t tail_lsn; + bool last_ref; + + lockdep_assert_held(&log->l_icloglock); + + trace_xlog_iclog_release(iclog, _RET_IP_); + /* + * Grabbing the current log tail needs to be atomic w.r.t. the writing + * of the tail LSN into the iclog so we guarantee that the log tail does + * not move between the first time we know that the iclog needs to be + * made stable and when we eventually submit it. + */ + if ((iclog->ic_state == XLOG_STATE_WANT_SYNC || + (iclog->ic_flags & XLOG_ICL_NEED_FUA)) && + !iclog->ic_header.h_tail_lsn) { + tail_lsn = xlog_assign_tail_lsn(log->l_mp); + iclog->ic_header.h_tail_lsn = cpu_to_be64(tail_lsn); + } + + last_ref = atomic_dec_and_test(&iclog->ic_refcnt); + + if (xlog_is_shutdown(log)) { + /* + * If there are no more references to this iclog, process the + * pending iclog callbacks that were waiting on the release of + * this iclog. + */ + if (last_ref) + xlog_state_shutdown_callbacks(log); + return -EIO; + } + + if (!last_ref) + return 0; + + if (iclog->ic_state != XLOG_STATE_WANT_SYNC) { + ASSERT(iclog->ic_state == XLOG_STATE_ACTIVE); + return 0; + } + + iclog->ic_state = XLOG_STATE_SYNCING; + xlog_verify_tail_lsn(log, iclog); + trace_xlog_iclog_syncing(iclog, _RET_IP_); + + spin_unlock(&log->l_icloglock); + xlog_sync(log, iclog, ticket); + spin_lock(&log->l_icloglock); + return 0; +} + +/* + * 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) +{ + struct xlog *log; + bool fatal = xfs_has_crc(mp); + int error = 0; + int min_logfsbs; + + if (!xfs_has_norecovery(mp)) { + xfs_notice(mp, "Mounting V%d Filesystem", + XFS_SB_VERSION_NUM(&mp->m_sb)); + } else { + xfs_notice(mp, +"Mounting V%d filesystem in no-recovery mode. Filesystem will be inconsistent.", + XFS_SB_VERSION_NUM(&mp->m_sb)); + ASSERT(xfs_is_readonly(mp)); + } + + log = xlog_alloc_log(mp, log_target, blk_offset, num_bblks); + if (IS_ERR(log)) { + error = PTR_ERR(log); + goto out; + } + mp->m_log = log; + + /* + * Validate the given log space and drop a critical message via syslog + * if the log size is too small that would lead to some unexpected + * situations in transaction log space reservation stage. + * + * Note: we can't just reject the mount if the validation fails. This + * would mean that people would have to downgrade their kernel just to + * remedy the situation as there is no way to grow the log (short of + * black magic surgery with xfs_db). + * + * We can, however, reject mounts for CRC format filesystems, as the + * mkfs binary being used to make the filesystem should never create a + * filesystem with a log that is too small. + */ + min_logfsbs = xfs_log_calc_minimum_size(mp); + + if (mp->m_sb.sb_logblocks < min_logfsbs) { + xfs_warn(mp, + "Log size %d blocks too small, minimum size is %d blocks", + mp->m_sb.sb_logblocks, min_logfsbs); + error = -EINVAL; + } else if (mp->m_sb.sb_logblocks > XFS_MAX_LOG_BLOCKS) { + xfs_warn(mp, + "Log size %d blocks too large, maximum size is %lld blocks", + mp->m_sb.sb_logblocks, XFS_MAX_LOG_BLOCKS); + error = -EINVAL; + } else if (XFS_FSB_TO_B(mp, mp->m_sb.sb_logblocks) > XFS_MAX_LOG_BYTES) { + xfs_warn(mp, + "log size %lld bytes too large, maximum size is %lld bytes", + XFS_FSB_TO_B(mp, mp->m_sb.sb_logblocks), + XFS_MAX_LOG_BYTES); + error = -EINVAL; + } else if (mp->m_sb.sb_logsunit > 1 && + mp->m_sb.sb_logsunit % mp->m_sb.sb_blocksize) { + xfs_warn(mp, + "log stripe unit %u bytes must be a multiple of block size", + mp->m_sb.sb_logsunit); + error = -EINVAL; + fatal = true; + } + if (error) { + /* + * Log check errors are always fatal on v5; or whenever bad + * metadata leads to a crash. + */ + if (fatal) { + xfs_crit(mp, "AAIEEE! Log failed size checks. Abort!"); + ASSERT(0); + goto out_free_log; + } + xfs_crit(mp, "Log size out of supported range."); + xfs_crit(mp, +"Continuing onwards, but if log hangs are experienced then please report this message in the bug report."); + } + + /* + * Initialize the AIL now we have a log. + */ + error = xfs_trans_ail_init(mp); + if (error) { + xfs_warn(mp, "AIL initialisation failed: error %d", error); + goto out_free_log; + } + log->l_ailp = mp->m_ail; + + /* + * skip log recovery on a norecovery mount. pretend it all + * just worked. + */ + if (!xfs_has_norecovery(mp)) { + /* + * log recovery ignores readonly state and so we need to clear + * mount-based read only state so it can write to disk. + */ + bool readonly = test_and_clear_bit(XFS_OPSTATE_READONLY, + &mp->m_opstate); + error = xlog_recover(log); + if (readonly) + set_bit(XFS_OPSTATE_READONLY, &mp->m_opstate); + if (error) { + xfs_warn(mp, "log mount/recovery failed: error %d", + error); + xlog_recover_cancel(log); + goto out_destroy_ail; + } + } + + error = xfs_sysfs_init(&log->l_kobj, &xfs_log_ktype, &mp->m_kobj, + "log"); + if (error) + goto out_destroy_ail; + + /* Normal transactions can now occur */ + clear_bit(XLOG_ACTIVE_RECOVERY, &log->l_opstate); + + /* + * Now the log has been fully initialised and we know were our + * space grant counters are, we can initialise the permanent ticket + * needed for delayed logging to work. + */ + xlog_cil_init_post_recovery(log); + + return 0; + +out_destroy_ail: + xfs_trans_ail_destroy(mp); +out_free_log: + xlog_dealloc_log(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. + * + * If we finish recovery successfully, start the background log work. If we are + * not doing recovery, then we have a RO filesystem and we don't need to start + * it. + */ +int +xfs_log_mount_finish( + struct xfs_mount *mp) +{ + struct xlog *log = mp->m_log; + bool readonly; + int error = 0; + + if (xfs_has_norecovery(mp)) { + ASSERT(xfs_is_readonly(mp)); + return 0; + } + + /* + * log recovery ignores readonly state and so we need to clear + * mount-based read only state so it can write to disk. + */ + readonly = test_and_clear_bit(XFS_OPSTATE_READONLY, &mp->m_opstate); + + /* + * During the second phase of log recovery, we need iget and + * iput to behave like they do for an active filesystem. + * xfs_fs_drop_inode needs to be able to prevent the deletion + * of inodes before we're done replaying log items on those + * inodes. Turn it off immediately after recovery finishes + * so that we don't leak the quota inodes if subsequent mount + * activities fail. + * + * We let all inodes involved in redo item processing end up on + * the LRU instead of being evicted immediately so that if we do + * something to an unlinked inode, the irele won't cause + * premature truncation and freeing of the inode, which results + * in log recovery failure. We have to evict the unreferenced + * lru inodes after clearing SB_ACTIVE because we don't + * otherwise clean up the lru if there's a subsequent failure in + * xfs_mountfs, which leads to us leaking the inodes if nothing + * else (e.g. quotacheck) references the inodes before the + * mount failure occurs. + */ + mp->m_super->s_flags |= SB_ACTIVE; + xfs_log_work_queue(mp); + if (xlog_recovery_needed(log)) + error = xlog_recover_finish(log); + mp->m_super->s_flags &= ~SB_ACTIVE; + evict_inodes(mp->m_super); + + /* + * Drain the buffer LRU after log recovery. This is required for v4 + * filesystems to avoid leaving around buffers with NULL verifier ops, + * but we do it unconditionally to make sure we're always in a clean + * cache state after mount. + * + * Don't push in the error case because the AIL may have pending intents + * that aren't removed until recovery is cancelled. + */ + if (xlog_recovery_needed(log)) { + if (!error) { + xfs_log_force(mp, XFS_LOG_SYNC); + xfs_ail_push_all_sync(mp->m_ail); + } + xfs_notice(mp, "Ending recovery (logdev: %s)", + mp->m_logname ? mp->m_logname : "internal"); + } else { + xfs_info(mp, "Ending clean mount"); + } + xfs_buftarg_drain(mp->m_ddev_targp); + + clear_bit(XLOG_RECOVERY_NEEDED, &log->l_opstate); + if (readonly) + set_bit(XFS_OPSTATE_READONLY, &mp->m_opstate); + + /* Make sure the log is dead if we're returning failure. */ + ASSERT(!error || xlog_is_shutdown(log)); + + return error; +} + +/* + * The mount has failed. Cancel the recovery if it hasn't completed and destroy + * the log. + */ +void +xfs_log_mount_cancel( + struct xfs_mount *mp) +{ + xlog_recover_cancel(mp->m_log); + xfs_log_unmount(mp); +} + +/* + * Flush out the iclog to disk ensuring that device caches are flushed and + * the iclog hits stable storage before any completion waiters are woken. + */ +static inline int +xlog_force_iclog( + struct xlog_in_core *iclog) +{ + atomic_inc(&iclog->ic_refcnt); + iclog->ic_flags |= XLOG_ICL_NEED_FLUSH | XLOG_ICL_NEED_FUA; + if (iclog->ic_state == XLOG_STATE_ACTIVE) + xlog_state_switch_iclogs(iclog->ic_log, iclog, 0); + return xlog_state_release_iclog(iclog->ic_log, iclog, NULL); +} + +/* + * Wait for the iclog and all prior iclogs to be written disk as required by the + * log force state machine. Waiting on ic_force_wait ensures iclog completions + * have been ordered and callbacks run before we are woken here, hence + * guaranteeing that all the iclogs up to this one are on stable storage. + */ +int +xlog_wait_on_iclog( + struct xlog_in_core *iclog) + __releases(iclog->ic_log->l_icloglock) +{ + struct xlog *log = iclog->ic_log; + + trace_xlog_iclog_wait_on(iclog, _RET_IP_); + if (!xlog_is_shutdown(log) && + iclog->ic_state != XLOG_STATE_ACTIVE && + iclog->ic_state != XLOG_STATE_DIRTY) { + XFS_STATS_INC(log->l_mp, xs_log_force_sleep); + xlog_wait(&iclog->ic_force_wait, &log->l_icloglock); + } else { + spin_unlock(&log->l_icloglock); + } + + if (xlog_is_shutdown(log)) + return -EIO; + return 0; +} + +/* + * Write out an unmount record using the ticket provided. We have to account for + * the data space used in the unmount ticket as this write is not done from a + * transaction context that has already done the accounting for us. + */ +static int +xlog_write_unmount_record( + struct xlog *log, + struct xlog_ticket *ticket) +{ + struct { + struct xlog_op_header ophdr; + struct xfs_unmount_log_format ulf; + } unmount_rec = { + .ophdr = { + .oh_clientid = XFS_LOG, + .oh_tid = cpu_to_be32(ticket->t_tid), + .oh_flags = XLOG_UNMOUNT_TRANS, + }, + .ulf = { + .magic = XLOG_UNMOUNT_TYPE, + }, + }; + struct xfs_log_iovec reg = { + .i_addr = &unmount_rec, + .i_len = sizeof(unmount_rec), + .i_type = XLOG_REG_TYPE_UNMOUNT, + }; + struct xfs_log_vec vec = { + .lv_niovecs = 1, + .lv_iovecp = ®, + }; + LIST_HEAD(lv_chain); + list_add(&vec.lv_list, &lv_chain); + + BUILD_BUG_ON((sizeof(struct xlog_op_header) + + sizeof(struct xfs_unmount_log_format)) != + sizeof(unmount_rec)); + + /* account for space used by record data */ + ticket->t_curr_res -= sizeof(unmount_rec); + + return xlog_write(log, NULL, &lv_chain, ticket, reg.i_len); +} + +/* + * Mark the filesystem clean by writing an unmount record to the head of the + * log. + */ +static void +xlog_unmount_write( + struct xlog *log) +{ + struct xfs_mount *mp = log->l_mp; + struct xlog_in_core *iclog; + struct xlog_ticket *tic = NULL; + int error; + + error = xfs_log_reserve(mp, 600, 1, &tic, 0); + if (error) + goto out_err; + + error = xlog_write_unmount_record(log, tic); + /* + * At this point, we're umounting anyway, so there's no point in + * transitioning log state to shutdown. Just continue... + */ +out_err: + if (error) + xfs_alert(mp, "%s: unmount record failed", __func__); + + spin_lock(&log->l_icloglock); + iclog = log->l_iclog; + error = xlog_force_iclog(iclog); + xlog_wait_on_iclog(iclog); + + if (tic) { + trace_xfs_log_umount_write(log, tic); + xfs_log_ticket_ungrant(log, tic); + } +} + +static void +xfs_log_unmount_verify_iclog( + struct xlog *log) +{ + struct xlog_in_core *iclog = log->l_iclog; + + do { + ASSERT(iclog->ic_state == XLOG_STATE_ACTIVE); + ASSERT(iclog->ic_offset == 0); + } while ((iclog = iclog->ic_next) != log->l_iclog); +} + +/* + * 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 "Unmount" is a bit foo. + * As far as I know, there weren't any dependencies on the old behaviour. + */ +static void +xfs_log_unmount_write( + struct xfs_mount *mp) +{ + struct xlog *log = mp->m_log; + + if (!xfs_log_writable(mp)) + return; + + xfs_log_force(mp, XFS_LOG_SYNC); + + if (xlog_is_shutdown(log)) + return; + + /* + * If we think the summary counters are bad, avoid writing the unmount + * record to force log recovery at next mount, after which the summary + * counters will be recalculated. Refer to xlog_check_unmount_rec for + * more details. + */ + if (XFS_TEST_ERROR(xfs_fs_has_sickness(mp, XFS_SICK_FS_COUNTERS), mp, + XFS_ERRTAG_FORCE_SUMMARY_RECALC)) { + xfs_alert(mp, "%s: will fix summary counters at next mount", + __func__); + return; + } + + xfs_log_unmount_verify_iclog(log); + xlog_unmount_write(log); +} + +/* + * Empty the log for unmount/freeze. + * + * To do this, we first need to shut down the background log work so it is not + * trying to cover the log as we clean up. We then need to unpin all objects in + * the log so we can then flush them out. Once they have completed their IO and + * run the callbacks removing themselves from the AIL, we can cover the log. + */ +int +xfs_log_quiesce( + struct xfs_mount *mp) +{ + /* + * Clear log incompat features since we're quiescing the log. Report + * failures, though it's not fatal to have a higher log feature + * protection level than the log contents actually require. + */ + if (xfs_clear_incompat_log_features(mp)) { + int error; + + error = xfs_sync_sb(mp, false); + if (error) + xfs_warn(mp, + "Failed to clear log incompat features on quiesce"); + } + + cancel_delayed_work_sync(&mp->m_log->l_work); + xfs_log_force(mp, XFS_LOG_SYNC); + + /* + * The superblock buffer is uncached and while xfs_ail_push_all_sync() + * will push it, xfs_buftarg_wait() will not wait for it. Further, + * xfs_buf_iowait() cannot be used because it was pushed with the + * XBF_ASYNC flag set, so we need to use a lock/unlock pair to wait for + * the IO to complete. + */ + xfs_ail_push_all_sync(mp->m_ail); + xfs_buftarg_wait(mp->m_ddev_targp); + xfs_buf_lock(mp->m_sb_bp); + xfs_buf_unlock(mp->m_sb_bp); + + return xfs_log_cover(mp); +} + +void +xfs_log_clean( + struct xfs_mount *mp) +{ + xfs_log_quiesce(mp); + xfs_log_unmount_write(mp); +} + +/* + * Shut down and release the AIL and Log. + * + * During unmount, we need to ensure we flush all the dirty metadata objects + * from the AIL so that the log is empty before we write the unmount record to + * the log. Once this is done, we can tear down the AIL and the log. + */ +void +xfs_log_unmount( + struct xfs_mount *mp) +{ + xfs_log_clean(mp); + + xfs_buftarg_drain(mp->m_ddev_targp); + + xfs_trans_ail_destroy(mp); + + xfs_sysfs_del(&mp->m_log->l_kobj); + + xlog_dealloc_log(mp->m_log); +} + +void +xfs_log_item_init( + struct xfs_mount *mp, + struct xfs_log_item *item, + int type, + const struct xfs_item_ops *ops) +{ + item->li_log = mp->m_log; + item->li_ailp = mp->m_ail; + item->li_type = type; + item->li_ops = ops; + item->li_lv = NULL; + + INIT_LIST_HEAD(&item->li_ail); + INIT_LIST_HEAD(&item->li_cil); + INIT_LIST_HEAD(&item->li_bio_list); + INIT_LIST_HEAD(&item->li_trans); +} + +/* + * Wake up processes waiting for log space after we have moved the log tail. + */ +void +xfs_log_space_wake( + struct xfs_mount *mp) +{ + struct xlog *log = mp->m_log; + int free_bytes; + + if (xlog_is_shutdown(log)) + return; + + if (!list_empty_careful(&log->l_write_head.waiters)) { + ASSERT(!xlog_in_recovery(log)); + + spin_lock(&log->l_write_head.lock); + free_bytes = xlog_space_left(log, &log->l_write_head.grant); + xlog_grant_head_wake(log, &log->l_write_head, &free_bytes); + spin_unlock(&log->l_write_head.lock); + } + + if (!list_empty_careful(&log->l_reserve_head.waiters)) { + ASSERT(!xlog_in_recovery(log)); + + spin_lock(&log->l_reserve_head.lock); + free_bytes = xlog_space_left(log, &log->l_reserve_head.grant); + xlog_grant_head_wake(log, &log->l_reserve_head, &free_bytes); + spin_unlock(&log->l_reserve_head.lock); + } +} + +/* + * 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. That means the CIL, the AIL and the iclogs needs to be empty before + * we start attempting to cover the log. + * + * Only 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. + * + * If there are any items in the AIl or CIL, then we do not want to attempt to + * cover the log as we may be in a situation where there isn't log space + * available to run a dummy transaction and this can lead to deadlocks when the + * tail of the log is pinned by an item that is modified in the CIL. Hence + * there's no point in running a dummy transaction at this point because we + * can't start trying to idle the log until both the CIL and AIL are empty. + */ +static bool +xfs_log_need_covered( + struct xfs_mount *mp) +{ + struct xlog *log = mp->m_log; + bool needed = false; + + if (!xlog_cil_empty(log)) + return false; + + 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_ail_min_lsn(log->l_ailp)) + break; + if (!xlog_iclogs_empty(log)) + break; + + needed = true; + 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; + break; + default: + needed = true; + break; + } + spin_unlock(&log->l_icloglock); + return needed; +} + +/* + * Explicitly cover the log. This is similar to background log covering but + * intended for usage in quiesce codepaths. The caller is responsible to ensure + * the log is idle and suitable for covering. The CIL, iclog buffers and AIL + * must all be empty. + */ +static int +xfs_log_cover( + struct xfs_mount *mp) +{ + int error = 0; + bool need_covered; + + ASSERT((xlog_cil_empty(mp->m_log) && xlog_iclogs_empty(mp->m_log) && + !xfs_ail_min_lsn(mp->m_log->l_ailp)) || + xlog_is_shutdown(mp->m_log)); + + if (!xfs_log_writable(mp)) + return 0; + + /* + * xfs_log_need_covered() is not idempotent because it progresses the + * state machine if the log requires covering. Therefore, we must call + * this function once and use the result until we've issued an sb sync. + * Do so first to make that abundantly clear. + * + * Fall into the covering sequence if the log needs covering or the + * mount has lazy superblock accounting to sync to disk. The sb sync + * used for covering accumulates the in-core counters, so covering + * handles this for us. + */ + need_covered = xfs_log_need_covered(mp); + if (!need_covered && !xfs_has_lazysbcount(mp)) + return 0; + + /* + * To cover the log, commit the superblock twice (at most) in + * independent checkpoints. The first serves as a reference for the + * tail pointer. The sync transaction and AIL push empties the AIL and + * updates the in-core tail to the LSN of the first checkpoint. The + * second commit updates the on-disk tail with the in-core LSN, + * covering the log. Push the AIL one more time to leave it empty, as + * we found it. + */ + do { + error = xfs_sync_sb(mp, true); + if (error) + break; + xfs_ail_push_all_sync(mp->m_ail); + } while (xfs_log_need_covered(mp)); + + return error; +} + +/* + * We may be holding the log iclog lock upon entering this routine. + */ +xfs_lsn_t +xlog_assign_tail_lsn_locked( + struct xfs_mount *mp) +{ + struct xlog *log = mp->m_log; + struct xfs_log_item *lip; + xfs_lsn_t tail_lsn; + + assert_spin_locked(&mp->m_ail->ail_lock); + + /* + * To make sure we always have a valid LSN for the log tail we keep + * track of the last LSN which was committed in log->l_last_sync_lsn, + * and use that when the AIL was empty. + */ + lip = xfs_ail_min(mp->m_ail); + if (lip) + tail_lsn = lip->li_lsn; + else + tail_lsn = atomic64_read(&log->l_last_sync_lsn); + trace_xfs_log_assign_tail_lsn(log, tail_lsn); + atomic64_set(&log->l_tail_lsn, tail_lsn); + return tail_lsn; +} + +xfs_lsn_t +xlog_assign_tail_lsn( + struct xfs_mount *mp) +{ + xfs_lsn_t tail_lsn; + + spin_lock(&mp->m_ail->ail_lock); + tail_lsn = xlog_assign_tail_lsn_locked(mp); + spin_unlock(&mp->m_ail->ail_lock); + + return 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 + * + * If reservation head is behind the tail, we have a problem. Warn about it, + * but then treat it as if the log is empty. + * + * If the log is shut down, the head and tail may be invalid or out of whack, so + * shortcut invalidity asserts in this case so that we don't trigger them + * falsely. + */ +STATIC int +xlog_space_left( + struct xlog *log, + atomic64_t *head) +{ + int tail_bytes; + int tail_cycle; + int head_cycle; + int head_bytes; + + xlog_crack_grant_head(head, &head_cycle, &head_bytes); + xlog_crack_atomic_lsn(&log->l_tail_lsn, &tail_cycle, &tail_bytes); + tail_bytes = BBTOB(tail_bytes); + if (tail_cycle == head_cycle && head_bytes >= tail_bytes) + return log->l_logsize - (head_bytes - tail_bytes); + if (tail_cycle + 1 < head_cycle) + return 0; + + /* Ignore potential inconsistency when shutdown. */ + if (xlog_is_shutdown(log)) + return log->l_logsize; + + if (tail_cycle < head_cycle) { + ASSERT(tail_cycle == (head_cycle - 1)); + return tail_bytes - head_bytes; + } + + /* + * 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_alert(log->l_mp, "xlog_space_left: head behind tail"); + xfs_alert(log->l_mp, " tail_cycle = %d, tail_bytes = %d", + tail_cycle, tail_bytes); + xfs_alert(log->l_mp, " GH cycle = %d, GH bytes = %d", + head_cycle, head_bytes); + ASSERT(0); + return log->l_logsize; +} + + +static void +xlog_ioend_work( + struct work_struct *work) +{ + struct xlog_in_core *iclog = + container_of(work, struct xlog_in_core, ic_end_io_work); + struct xlog *log = iclog->ic_log; + int error; + + error = blk_status_to_errno(iclog->ic_bio.bi_status); +#ifdef DEBUG + /* treat writes with injected CRC errors as failed */ + if (iclog->ic_fail_crc) + error = -EIO; +#endif + + /* + * Race to shutdown the filesystem if we see an error. + */ + if (XFS_TEST_ERROR(error, log->l_mp, XFS_ERRTAG_IODONE_IOERR)) { + xfs_alert(log->l_mp, "log I/O error %d", error); + xlog_force_shutdown(log, SHUTDOWN_LOG_IO_ERROR); + } + + xlog_state_done_syncing(iclog); + bio_uninit(&iclog->ic_bio); + + /* + * Drop the lock to signal that we are done. Nothing references the + * iclog after this, so an unmount waiting on this lock can now tear it + * down safely. As such, it is unsafe to reference the iclog after the + * unlock as we could race with it being freed. + */ + up(&iclog->ic_sema); +} + +/* + * 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( + struct xfs_mount *mp, + struct xlog *log) +{ + if (mp->m_logbufs <= 0) + mp->m_logbufs = XLOG_MAX_ICLOGS; + if (mp->m_logbsize <= 0) + mp->m_logbsize = XLOG_BIG_RECORD_BSIZE; + + log->l_iclog_bufs = mp->m_logbufs; + log->l_iclog_size = mp->m_logbsize; + + /* + * # headers = size / 32k - one header holds cycles from 32k of data. + */ + log->l_iclog_heads = + DIV_ROUND_UP(mp->m_logbsize, XLOG_HEADER_CYCLE_SIZE); + log->l_iclog_hsize = log->l_iclog_heads << BBSHIFT; +} + +void +xfs_log_work_queue( + struct xfs_mount *mp) +{ + queue_delayed_work(mp->m_sync_workqueue, &mp->m_log->l_work, + msecs_to_jiffies(xfs_syncd_centisecs * 10)); +} + +/* + * Clear the log incompat flags if we have the opportunity. + * + * This only happens if we're about to log the second dummy transaction as part + * of covering the log and we can get the log incompat feature usage lock. + */ +static inline void +xlog_clear_incompat( + struct xlog *log) +{ + struct xfs_mount *mp = log->l_mp; + + if (!xfs_sb_has_incompat_log_feature(&mp->m_sb, + XFS_SB_FEAT_INCOMPAT_LOG_ALL)) + return; + + if (log->l_covered_state != XLOG_STATE_COVER_DONE2) + return; + + if (!down_write_trylock(&log->l_incompat_users)) + return; + + xfs_clear_incompat_log_features(mp); + up_write(&log->l_incompat_users); +} + +/* + * Every sync period we need to unpin all items in the AIL and push them to + * disk. If there is nothing dirty, then we might need to cover the log to + * indicate that the filesystem is idle. + */ +static void +xfs_log_worker( + struct work_struct *work) +{ + struct xlog *log = container_of(to_delayed_work(work), + struct xlog, l_work); + struct xfs_mount *mp = log->l_mp; + + /* dgc: errors ignored - not fatal and nowhere to report them */ + if (xfs_fs_writable(mp, SB_FREEZE_WRITE) && xfs_log_need_covered(mp)) { + /* + * Dump a transaction into the log that contains no real change. + * This is needed to stamp the current tail LSN into the log + * during the covering operation. + * + * We cannot use an inode here for this - that will push dirty + * state back up into the VFS and then periodic inode flushing + * will prevent log covering from making progress. Hence we + * synchronously log the superblock instead to ensure the + * superblock is immediately unpinned and can be written back. + */ + xlog_clear_incompat(log); + xfs_sync_sb(mp, true); + } else + xfs_log_force(mp, 0); + + /* start pushing all the metadata that is currently dirty */ + xfs_ail_push_all(mp->m_ail); + + /* queue us up again */ + xfs_log_work_queue(mp); +} + +/* + * 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 struct xlog * +xlog_alloc_log( + struct xfs_mount *mp, + struct xfs_buftarg *log_target, + xfs_daddr_t blk_offset, + int num_bblks) +{ + struct xlog *log; + xlog_rec_header_t *head; + xlog_in_core_t **iclogp; + xlog_in_core_t *iclog, *prev_iclog=NULL; + int i; + int error = -ENOMEM; + uint log2_size = 0; + + log = kmem_zalloc(sizeof(struct xlog), KM_MAYFAIL); + if (!log) { + xfs_warn(mp, "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; + set_bit(XLOG_ACTIVE_RECOVERY, &log->l_opstate); + INIT_DELAYED_WORK(&log->l_work, xfs_log_worker); + + log->l_prev_block = -1; + /* log->l_tail_lsn = 0x100000000LL; cycle = 1; current block = 0 */ + xlog_assign_atomic_lsn(&log->l_tail_lsn, 1, 0); + xlog_assign_atomic_lsn(&log->l_last_sync_lsn, 1, 0); + log->l_curr_cycle = 1; /* 0 is bad since this is initial value */ + + if (xfs_has_logv2(mp) && mp->m_sb.sb_logsunit > 1) + log->l_iclog_roundoff = mp->m_sb.sb_logsunit; + else + log->l_iclog_roundoff = BBSIZE; + + xlog_grant_head_init(&log->l_reserve_head); + xlog_grant_head_init(&log->l_write_head); + + error = -EFSCORRUPTED; + if (xfs_has_sector(mp)) { + log2_size = mp->m_sb.sb_logsectlog; + if (log2_size < BBSHIFT) { + xfs_warn(mp, "Log sector size too small (0x%x < 0x%x)", + log2_size, BBSHIFT); + goto out_free_log; + } + + log2_size -= BBSHIFT; + if (log2_size > mp->m_sectbb_log) { + xfs_warn(mp, "Log sector size too large (0x%x > 0x%x)", + log2_size, mp->m_sectbb_log); + goto out_free_log; + } + + /* for larger sector sizes, must have v2 or external log */ + if (log2_size && log->l_logBBstart > 0 && + !xfs_has_logv2(mp)) { + xfs_warn(mp, + "log sector size (0x%x) invalid for configuration.", + log2_size); + goto out_free_log; + } + } + log->l_sectBBsize = 1 << log2_size; + + init_rwsem(&log->l_incompat_users); + + xlog_get_iclog_buffer_size(mp, log); + + spin_lock_init(&log->l_icloglock); + init_waitqueue_head(&log->l_flush_wait); + + 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. + */ + ASSERT(log->l_iclog_size >= 4096); + for (i = 0; i < log->l_iclog_bufs; i++) { + size_t bvec_size = howmany(log->l_iclog_size, PAGE_SIZE) * + sizeof(struct bio_vec); + + iclog = kmem_zalloc(sizeof(*iclog) + bvec_size, KM_MAYFAIL); + if (!iclog) + goto out_free_iclog; + + *iclogp = iclog; + iclog->ic_prev = prev_iclog; + prev_iclog = iclog; + + iclog->ic_data = kvzalloc(log->l_iclog_size, + GFP_KERNEL | __GFP_RETRY_MAYFAIL); + if (!iclog->ic_data) + goto out_free_iclog; + 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_has_logv2(log->l_mp) ? 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 = log->l_iclog_size - log->l_iclog_hsize; + iclog->ic_state = XLOG_STATE_ACTIVE; + iclog->ic_log = log; + atomic_set(&iclog->ic_refcnt, 0); + INIT_LIST_HEAD(&iclog->ic_callbacks); + iclog->ic_datap = (void *)iclog->ic_data + log->l_iclog_hsize; + + init_waitqueue_head(&iclog->ic_force_wait); + init_waitqueue_head(&iclog->ic_write_wait); + INIT_WORK(&iclog->ic_end_io_work, xlog_ioend_work); + sema_init(&iclog->ic_sema, 1); + + iclogp = &iclog->ic_next; + } + *iclogp = log->l_iclog; /* complete ring */ + log->l_iclog->ic_prev = prev_iclog; /* re-write 1st prev ptr */ + + log->l_ioend_workqueue = alloc_workqueue("xfs-log/%s", + XFS_WQFLAGS(WQ_FREEZABLE | WQ_MEM_RECLAIM | + WQ_HIGHPRI), + 0, mp->m_super->s_id); + if (!log->l_ioend_workqueue) + goto out_free_iclog; + + error = xlog_cil_init(log); + if (error) + goto out_destroy_workqueue; + return log; + +out_destroy_workqueue: + destroy_workqueue(log->l_ioend_workqueue); +out_free_iclog: + for (iclog = log->l_iclog; iclog; iclog = prev_iclog) { + prev_iclog = iclog->ic_next; + kmem_free(iclog->ic_data); + kmem_free(iclog); + if (prev_iclog == log->l_iclog) + break; + } +out_free_log: + kmem_free(log); +out: + return ERR_PTR(error); +} /* xlog_alloc_log */ + +/* + * Compute the LSN that we'd need to push the log tail towards in order to have + * (a) enough on-disk log space to log the number of bytes specified, (b) at + * least 25% of the log space free, and (c) at least 256 blocks free. If the + * log free space already meets all three thresholds, this function returns + * NULLCOMMITLSN. + */ +xfs_lsn_t +xlog_grant_push_threshold( + struct xlog *log, + int need_bytes) +{ + xfs_lsn_t threshold_lsn = 0; + xfs_lsn_t last_sync_lsn; + int free_blocks; + int free_bytes; + int threshold_block; + int threshold_cycle; + int free_threshold; + + ASSERT(BTOBB(need_bytes) < log->l_logBBsize); + + free_bytes = xlog_space_left(log, &log->l_reserve_head.grant); + 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) + return NULLCOMMITLSN; + + xlog_crack_atomic_lsn(&log->l_tail_lsn, &threshold_cycle, + &threshold_block); + threshold_block += free_threshold; + 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. Use a snapshot of the last sync lsn + * so that it doesn't change between the compare and the set. + */ + last_sync_lsn = atomic64_read(&log->l_last_sync_lsn); + if (XFS_LSN_CMP(threshold_lsn, last_sync_lsn) > 0) + threshold_lsn = last_sync_lsn; + + return threshold_lsn; +} + +/* + * Push the tail of the log if we need to do so to maintain the free log space + * thresholds set out by xlog_grant_push_threshold. 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( + struct xlog *log, + int need_bytes) +{ + xfs_lsn_t threshold_lsn; + + threshold_lsn = xlog_grant_push_threshold(log, need_bytes); + if (threshold_lsn == NULLCOMMITLSN || xlog_is_shutdown(log)) + return; + + /* + * 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. + */ + xfs_ail_push(log->l_ailp, threshold_lsn); +} + +/* + * Stamp cycle number in every block + */ +STATIC void +xlog_pack_data( + struct xlog *log, + struct xlog_in_core *iclog, + int roundoff) +{ + int i, j, k; + int size = iclog->ic_offset + roundoff; + __be32 cycle_lsn; + char *dp; + + cycle_lsn = CYCLE_LSN_DISK(iclog->ic_header.h_lsn); + + dp = iclog->ic_datap; + for (i = 0; i < BTOBB(size); i++) { + if (i >= (XLOG_HEADER_CYCLE_SIZE / BBSIZE)) + break; + iclog->ic_header.h_cycle_data[i] = *(__be32 *)dp; + *(__be32 *)dp = cycle_lsn; + dp += BBSIZE; + } + + if (xfs_has_logv2(log->l_mp)) { + xlog_in_core_2_t *xhdr = iclog->ic_data; + + for ( ; i < BTOBB(size); i++) { + j = i / (XLOG_HEADER_CYCLE_SIZE / BBSIZE); + k = i % (XLOG_HEADER_CYCLE_SIZE / BBSIZE); + xhdr[j].hic_xheader.xh_cycle_data[k] = *(__be32 *)dp; + *(__be32 *)dp = cycle_lsn; + dp += BBSIZE; + } + + for (i = 1; i < log->l_iclog_heads; i++) + xhdr[i].hic_xheader.xh_cycle = cycle_lsn; + } +} + +/* + * Calculate the checksum for a log buffer. + * + * This is a little more complicated than it should be because the various + * headers and the actual data are non-contiguous. + */ +__le32 +xlog_cksum( + struct xlog *log, + struct xlog_rec_header *rhead, + char *dp, + int size) +{ + uint32_t crc; + + /* first generate the crc for the record header ... */ + crc = xfs_start_cksum_update((char *)rhead, + sizeof(struct xlog_rec_header), + offsetof(struct xlog_rec_header, h_crc)); + + /* ... then for additional cycle data for v2 logs ... */ + if (xfs_has_logv2(log->l_mp)) { + union xlog_in_core2 *xhdr = (union xlog_in_core2 *)rhead; + int i; + int xheads; + + xheads = DIV_ROUND_UP(size, XLOG_HEADER_CYCLE_SIZE); + + for (i = 1; i < xheads; i++) { + crc = crc32c(crc, &xhdr[i].hic_xheader, + sizeof(struct xlog_rec_ext_header)); + } + } + + /* ... and finally for the payload */ + crc = crc32c(crc, dp, size); + + return xfs_end_cksum(crc); +} + +static void +xlog_bio_end_io( + struct bio *bio) +{ + struct xlog_in_core *iclog = bio->bi_private; + + queue_work(iclog->ic_log->l_ioend_workqueue, + &iclog->ic_end_io_work); +} + +static int +xlog_map_iclog_data( + struct bio *bio, + void *data, + size_t count) +{ + do { + struct page *page = kmem_to_page(data); + unsigned int off = offset_in_page(data); + size_t len = min_t(size_t, count, PAGE_SIZE - off); + + if (bio_add_page(bio, page, len, off) != len) + return -EIO; + + data += len; + count -= len; + } while (count); + + return 0; +} + +STATIC void +xlog_write_iclog( + struct xlog *log, + struct xlog_in_core *iclog, + uint64_t bno, + unsigned int count) +{ + ASSERT(bno < log->l_logBBsize); + trace_xlog_iclog_write(iclog, _RET_IP_); + + /* + * We lock the iclogbufs here so that we can serialise against I/O + * completion during unmount. We might be processing a shutdown + * triggered during unmount, and that can occur asynchronously to the + * unmount thread, and hence we need to ensure that completes before + * tearing down the iclogbufs. Hence we need to hold the buffer lock + * across the log IO to archieve that. + */ + down(&iclog->ic_sema); + if (xlog_is_shutdown(log)) { + /* + * 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. We kick of the state machine and unlock + * the buffer manually, the code needs to be kept in sync + * with the I/O completion path. + */ + xlog_state_done_syncing(iclog); + up(&iclog->ic_sema); + return; + } + + /* + * We use REQ_SYNC | REQ_IDLE here to tell the block layer the are more + * IOs coming immediately after this one. This prevents the block layer + * writeback throttle from throttling log writes behind background + * metadata writeback and causing priority inversions. + */ + bio_init(&iclog->ic_bio, log->l_targ->bt_bdev, iclog->ic_bvec, + howmany(count, PAGE_SIZE), + REQ_OP_WRITE | REQ_META | REQ_SYNC | REQ_IDLE); + iclog->ic_bio.bi_iter.bi_sector = log->l_logBBstart + bno; + iclog->ic_bio.bi_end_io = xlog_bio_end_io; + iclog->ic_bio.bi_private = iclog; + + if (iclog->ic_flags & XLOG_ICL_NEED_FLUSH) { + iclog->ic_bio.bi_opf |= REQ_PREFLUSH; + /* + * For external log devices, we also need to flush the data + * device cache first to ensure all metadata writeback covered + * by the LSN in this iclog is on stable storage. This is slow, + * but it *must* complete before we issue the external log IO. + * + * If the flush fails, we cannot conclude that past metadata + * writeback from the log succeeded. Repeating the flush is + * not possible, hence we must shut down with log IO error to + * avoid shutdown re-entering this path and erroring out again. + */ + if (log->l_targ != log->l_mp->m_ddev_targp && + blkdev_issue_flush(log->l_mp->m_ddev_targp->bt_bdev)) { + xlog_force_shutdown(log, SHUTDOWN_LOG_IO_ERROR); + return; + } + } + if (iclog->ic_flags & XLOG_ICL_NEED_FUA) + iclog->ic_bio.bi_opf |= REQ_FUA; + + iclog->ic_flags &= ~(XLOG_ICL_NEED_FLUSH | XLOG_ICL_NEED_FUA); + + if (xlog_map_iclog_data(&iclog->ic_bio, iclog->ic_data, count)) { + xlog_force_shutdown(log, SHUTDOWN_LOG_IO_ERROR); + return; + } + if (is_vmalloc_addr(iclog->ic_data)) + flush_kernel_vmap_range(iclog->ic_data, count); + + /* + * If this log buffer would straddle the end of the log we will have + * to split it up into two bios, so that we can continue at the start. + */ + if (bno + BTOBB(count) > log->l_logBBsize) { + struct bio *split; + + split = bio_split(&iclog->ic_bio, log->l_logBBsize - bno, + GFP_NOIO, &fs_bio_set); + bio_chain(split, &iclog->ic_bio); + submit_bio(split); + + /* restart at logical offset zero for the remainder */ + iclog->ic_bio.bi_iter.bi_sector = log->l_logBBstart; + } + + submit_bio(&iclog->ic_bio); +} + +/* + * We need to bump cycle number for the part of the iclog that is + * written to the start of the log. Watch out for the header magic + * number case, though. + */ +static void +xlog_split_iclog( + struct xlog *log, + void *data, + uint64_t bno, + unsigned int count) +{ + unsigned int split_offset = BBTOB(log->l_logBBsize - bno); + unsigned int i; + + for (i = split_offset; i < count; i += BBSIZE) { + uint32_t cycle = get_unaligned_be32(data + i); + + if (++cycle == XLOG_HEADER_MAGIC_NUM) + cycle++; + put_unaligned_be32(cycle, data + i); + } +} + +static int +xlog_calc_iclog_size( + struct xlog *log, + struct xlog_in_core *iclog, + uint32_t *roundoff) +{ + uint32_t count_init, count; + + /* Add for LR header */ + count_init = log->l_iclog_hsize + iclog->ic_offset; + count = roundup(count_init, log->l_iclog_roundoff); + + *roundoff = count - count_init; + + ASSERT(count >= count_init); + ASSERT(*roundoff < log->l_iclog_roundoff); + return count; +} + +/* + * 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 + * xlog_write_iclog knows about the fact that the log may not start with + * block zero on a given device. + */ +STATIC void +xlog_sync( + struct xlog *log, + struct xlog_in_core *iclog, + struct xlog_ticket *ticket) +{ + unsigned int count; /* byte count of bwrite */ + unsigned int roundoff; /* roundoff to BB or stripe */ + uint64_t bno; + unsigned int size; + + ASSERT(atomic_read(&iclog->ic_refcnt) == 0); + trace_xlog_iclog_sync(iclog, _RET_IP_); + + count = xlog_calc_iclog_size(log, iclog, &roundoff); + + /* + * If we have a ticket, account for the roundoff via the ticket + * reservation to avoid touching the hot grant heads needlessly. + * Otherwise, we have to move grant heads directly. + */ + if (ticket) { + ticket->t_curr_res -= roundoff; + } else { + xlog_grant_add_space(log, &log->l_reserve_head.grant, roundoff); + xlog_grant_add_space(log, &log->l_write_head.grant, roundoff); + } + + /* put cycle number in every block */ + xlog_pack_data(log, iclog, roundoff); + + /* real byte length */ + size = iclog->ic_offset; + if (xfs_has_logv2(log->l_mp)) + size += roundoff; + iclog->ic_header.h_len = cpu_to_be32(size); + + XFS_STATS_INC(log->l_mp, xs_log_writes); + XFS_STATS_ADD(log->l_mp, xs_log_blocks, BTOBB(count)); + + bno = BLOCK_LSN(be64_to_cpu(iclog->ic_header.h_lsn)); + + /* Do we need to split this write into 2 parts? */ + if (bno + BTOBB(count) > log->l_logBBsize) + xlog_split_iclog(log, &iclog->ic_header, bno, count); + + /* calculcate the checksum */ + iclog->ic_header.h_crc = xlog_cksum(log, &iclog->ic_header, + iclog->ic_datap, size); + /* + * Intentionally corrupt the log record CRC based on the error injection + * frequency, if defined. This facilitates testing log recovery in the + * event of torn writes. Hence, set the IOABORT state to abort the log + * write on I/O completion and shutdown the fs. The subsequent mount + * detects the bad CRC and attempts to recover. + */ +#ifdef DEBUG + if (XFS_TEST_ERROR(false, log->l_mp, XFS_ERRTAG_LOG_BAD_CRC)) { + iclog->ic_header.h_crc &= cpu_to_le32(0xAAAAAAAA); + iclog->ic_fail_crc = true; + xfs_warn(log->l_mp, + "Intentionally corrupted log record at LSN 0x%llx. Shutdown imminent.", + be64_to_cpu(iclog->ic_header.h_lsn)); + } +#endif + xlog_verify_iclog(log, iclog, count); + xlog_write_iclog(log, iclog, bno, count); +} + +/* + * Deallocate a log structure + */ +STATIC void +xlog_dealloc_log( + struct xlog *log) +{ + xlog_in_core_t *iclog, *next_iclog; + int i; + + /* + * Cycle all the iclogbuf locks to make sure all log IO completion + * is done before we tear down these buffers. + */ + iclog = log->l_iclog; + for (i = 0; i < log->l_iclog_bufs; i++) { + down(&iclog->ic_sema); + up(&iclog->ic_sema); + iclog = iclog->ic_next; + } + + /* + * Destroy the CIL after waiting for iclog IO completion because an + * iclog EIO error will try to shut down the log, which accesses the + * CIL to wake up the waiters. + */ + xlog_cil_destroy(log); + + iclog = log->l_iclog; + for (i = 0; i < log->l_iclog_bufs; i++) { + next_iclog = iclog->ic_next; + kmem_free(iclog->ic_data); + kmem_free(iclog); + iclog = next_iclog; + } + + log->l_mp->m_log = NULL; + destroy_workqueue(log->l_ioend_workqueue); + kmem_free(log); +} + +/* + * Update counters atomically now that memcpy is done. + */ +static inline void +xlog_state_finish_copy( + struct xlog *log, + struct xlog_in_core *iclog, + int record_cnt, + int copy_bytes) +{ + lockdep_assert_held(&log->l_icloglock); + + be32_add_cpu(&iclog->ic_header.h_num_logops, record_cnt); + iclog->ic_offset += copy_bytes; +} + +/* + * print out info relating to regions written which consume + * the reservation + */ +void +xlog_print_tic_res( + struct xfs_mount *mp, + struct xlog_ticket *ticket) +{ + xfs_warn(mp, "ticket reservation summary:"); + xfs_warn(mp, " unit res = %d bytes", ticket->t_unit_res); + xfs_warn(mp, " current res = %d bytes", ticket->t_curr_res); + xfs_warn(mp, " original count = %d", ticket->t_ocnt); + xfs_warn(mp, " remaining count = %d", ticket->t_cnt); +} + +/* + * Print a summary of the transaction. + */ +void +xlog_print_trans( + struct xfs_trans *tp) +{ + struct xfs_mount *mp = tp->t_mountp; + struct xfs_log_item *lip; + + /* dump core transaction and ticket info */ + xfs_warn(mp, "transaction summary:"); + xfs_warn(mp, " log res = %d", tp->t_log_res); + xfs_warn(mp, " log count = %d", tp->t_log_count); + xfs_warn(mp, " flags = 0x%x", tp->t_flags); + + xlog_print_tic_res(mp, tp->t_ticket); + + /* dump each log item */ + list_for_each_entry(lip, &tp->t_items, li_trans) { + struct xfs_log_vec *lv = lip->li_lv; + struct xfs_log_iovec *vec; + int i; + + xfs_warn(mp, "log item: "); + xfs_warn(mp, " type = 0x%x", lip->li_type); + xfs_warn(mp, " flags = 0x%lx", lip->li_flags); + if (!lv) + continue; + xfs_warn(mp, " niovecs = %d", lv->lv_niovecs); + xfs_warn(mp, " size = %d", lv->lv_size); + xfs_warn(mp, " bytes = %d", lv->lv_bytes); + xfs_warn(mp, " buf len = %d", lv->lv_buf_len); + + /* dump each iovec for the log item */ + vec = lv->lv_iovecp; + for (i = 0; i < lv->lv_niovecs; i++) { + int dumplen = min(vec->i_len, 32); + + xfs_warn(mp, " iovec[%d]", i); + xfs_warn(mp, " type = 0x%x", vec->i_type); + xfs_warn(mp, " len = %d", vec->i_len); + xfs_warn(mp, " first %d bytes of iovec[%d]:", dumplen, i); + xfs_hex_dump(vec->i_addr, dumplen); + + vec++; + } + } +} + +static inline void +xlog_write_iovec( + struct xlog_in_core *iclog, + uint32_t *log_offset, + void *data, + uint32_t write_len, + int *bytes_left, + uint32_t *record_cnt, + uint32_t *data_cnt) +{ + ASSERT(*log_offset < iclog->ic_log->l_iclog_size); + ASSERT(*log_offset % sizeof(int32_t) == 0); + ASSERT(write_len % sizeof(int32_t) == 0); + + memcpy(iclog->ic_datap + *log_offset, data, write_len); + *log_offset += write_len; + *bytes_left -= write_len; + (*record_cnt)++; + *data_cnt += write_len; +} + +/* + * Write log vectors into a single iclog which is guaranteed by the caller + * to have enough space to write the entire log vector into. + */ +static void +xlog_write_full( + struct xfs_log_vec *lv, + struct xlog_ticket *ticket, + struct xlog_in_core *iclog, + uint32_t *log_offset, + uint32_t *len, + uint32_t *record_cnt, + uint32_t *data_cnt) +{ + int index; + + ASSERT(*log_offset + *len <= iclog->ic_size || + iclog->ic_state == XLOG_STATE_WANT_SYNC); + + /* + * Ordered log vectors have no regions to write so this + * loop will naturally skip them. + */ + for (index = 0; index < lv->lv_niovecs; index++) { + struct xfs_log_iovec *reg = &lv->lv_iovecp[index]; + struct xlog_op_header *ophdr = reg->i_addr; + + ophdr->oh_tid = cpu_to_be32(ticket->t_tid); + xlog_write_iovec(iclog, log_offset, reg->i_addr, + reg->i_len, len, record_cnt, data_cnt); + } +} + +static int +xlog_write_get_more_iclog_space( + struct xlog_ticket *ticket, + struct xlog_in_core **iclogp, + uint32_t *log_offset, + uint32_t len, + uint32_t *record_cnt, + uint32_t *data_cnt) +{ + struct xlog_in_core *iclog = *iclogp; + struct xlog *log = iclog->ic_log; + int error; + + spin_lock(&log->l_icloglock); + ASSERT(iclog->ic_state == XLOG_STATE_WANT_SYNC); + xlog_state_finish_copy(log, iclog, *record_cnt, *data_cnt); + error = xlog_state_release_iclog(log, iclog, ticket); + spin_unlock(&log->l_icloglock); + if (error) + return error; + + error = xlog_state_get_iclog_space(log, len, &iclog, ticket, + log_offset); + if (error) + return error; + *record_cnt = 0; + *data_cnt = 0; + *iclogp = iclog; + return 0; +} + +/* + * Write log vectors into a single iclog which is smaller than the current chain + * length. We write until we cannot fit a full record into the remaining space + * and then stop. We return the log vector that is to be written that cannot + * wholly fit in the iclog. + */ +static int +xlog_write_partial( + struct xfs_log_vec *lv, + struct xlog_ticket *ticket, + struct xlog_in_core **iclogp, + uint32_t *log_offset, + uint32_t *len, + uint32_t *record_cnt, + uint32_t *data_cnt) +{ + struct xlog_in_core *iclog = *iclogp; + struct xlog_op_header *ophdr; + int index = 0; + uint32_t rlen; + int error; + + /* walk the logvec, copying until we run out of space in the iclog */ + for (index = 0; index < lv->lv_niovecs; index++) { + struct xfs_log_iovec *reg = &lv->lv_iovecp[index]; + uint32_t reg_offset = 0; + + /* + * The first region of a continuation must have a non-zero + * length otherwise log recovery will just skip over it and + * start recovering from the next opheader it finds. Because we + * mark the next opheader as a continuation, recovery will then + * incorrectly add the continuation to the previous region and + * that breaks stuff. + * + * Hence if there isn't space for region data after the + * opheader, then we need to start afresh with a new iclog. + */ + if (iclog->ic_size - *log_offset <= + sizeof(struct xlog_op_header)) { + error = xlog_write_get_more_iclog_space(ticket, + &iclog, log_offset, *len, record_cnt, + data_cnt); + if (error) + return error; + } + + ophdr = reg->i_addr; + rlen = min_t(uint32_t, reg->i_len, iclog->ic_size - *log_offset); + + ophdr->oh_tid = cpu_to_be32(ticket->t_tid); + ophdr->oh_len = cpu_to_be32(rlen - sizeof(struct xlog_op_header)); + if (rlen != reg->i_len) + ophdr->oh_flags |= XLOG_CONTINUE_TRANS; + + xlog_write_iovec(iclog, log_offset, reg->i_addr, + rlen, len, record_cnt, data_cnt); + + /* If we wrote the whole region, move to the next. */ + if (rlen == reg->i_len) + continue; + + /* + * We now have a partially written iovec, but it can span + * multiple iclogs so we loop here. First we release the iclog + * we currently have, then we get a new iclog and add a new + * opheader. Then we continue copying from where we were until + * we either complete the iovec or fill the iclog. If we + * complete the iovec, then we increment the index and go right + * back to the top of the outer loop. if we fill the iclog, we + * run the inner loop again. + * + * This is complicated by the tail of a region using all the + * space in an iclog and hence requiring us to release the iclog + * and get a new one before returning to the outer loop. We must + * always guarantee that we exit this inner loop with at least + * space for log transaction opheaders left in the current + * iclog, hence we cannot just terminate the loop at the end + * of the of the continuation. So we loop while there is no + * space left in the current iclog, and check for the end of the + * continuation after getting a new iclog. + */ + do { + /* + * Ensure we include the continuation opheader in the + * space we need in the new iclog by adding that size + * to the length we require. This continuation opheader + * needs to be accounted to the ticket as the space it + * consumes hasn't been accounted to the lv we are + * writing. + */ + error = xlog_write_get_more_iclog_space(ticket, + &iclog, log_offset, + *len + sizeof(struct xlog_op_header), + record_cnt, data_cnt); + if (error) + return error; + + ophdr = iclog->ic_datap + *log_offset; + ophdr->oh_tid = cpu_to_be32(ticket->t_tid); + ophdr->oh_clientid = XFS_TRANSACTION; + ophdr->oh_res2 = 0; + ophdr->oh_flags = XLOG_WAS_CONT_TRANS; + + ticket->t_curr_res -= sizeof(struct xlog_op_header); + *log_offset += sizeof(struct xlog_op_header); + *data_cnt += sizeof(struct xlog_op_header); + + /* + * If rlen fits in the iclog, then end the region + * continuation. Otherwise we're going around again. + */ + reg_offset += rlen; + rlen = reg->i_len - reg_offset; + if (rlen <= iclog->ic_size - *log_offset) + ophdr->oh_flags |= XLOG_END_TRANS; + else + ophdr->oh_flags |= XLOG_CONTINUE_TRANS; + + rlen = min_t(uint32_t, rlen, iclog->ic_size - *log_offset); + ophdr->oh_len = cpu_to_be32(rlen); + + xlog_write_iovec(iclog, log_offset, + reg->i_addr + reg_offset, + rlen, len, record_cnt, data_cnt); + + } while (ophdr->oh_flags & XLOG_CONTINUE_TRANS); + } + + /* + * No more iovecs remain in this logvec so return the next log vec to + * the caller so it can go back to fast path copying. + */ + *iclogp = 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. + */ +int +xlog_write( + struct xlog *log, + struct xfs_cil_ctx *ctx, + struct list_head *lv_chain, + struct xlog_ticket *ticket, + uint32_t len) + +{ + struct xlog_in_core *iclog = NULL; + struct xfs_log_vec *lv; + uint32_t record_cnt = 0; + uint32_t data_cnt = 0; + int error = 0; + int log_offset; + + if (ticket->t_curr_res < 0) { + xfs_alert_tag(log->l_mp, XFS_PTAG_LOGRES, + "ctx ticket reservation ran out. Need to up reservation"); + xlog_print_tic_res(log->l_mp, ticket); + xlog_force_shutdown(log, SHUTDOWN_LOG_IO_ERROR); + } + + error = xlog_state_get_iclog_space(log, len, &iclog, ticket, + &log_offset); + if (error) + return error; + + ASSERT(log_offset <= iclog->ic_size - 1); + + /* + * If we have a context pointer, pass it the first iclog we are + * writing to so it can record state needed for iclog write + * ordering. + */ + if (ctx) + xlog_cil_set_ctx_write_state(ctx, iclog); + + list_for_each_entry(lv, lv_chain, lv_list) { + /* + * If the entire log vec does not fit in the iclog, punt it to + * the partial copy loop which can handle this case. + */ + if (lv->lv_niovecs && + lv->lv_bytes > iclog->ic_size - log_offset) { + error = xlog_write_partial(lv, ticket, &iclog, + &log_offset, &len, &record_cnt, + &data_cnt); + if (error) { + /* + * We have no iclog to release, so just return + * the error immediately. + */ + return error; + } + } else { + xlog_write_full(lv, ticket, iclog, &log_offset, + &len, &record_cnt, &data_cnt); + } + } + ASSERT(len == 0); + + /* + * We've already been guaranteed that the last writes will fit inside + * the current iclog, and hence it will already have the space used by + * those writes accounted to it. Hence we do not need to update the + * iclog with the number of bytes written here. + */ + spin_lock(&log->l_icloglock); + xlog_state_finish_copy(log, iclog, record_cnt, 0); + error = xlog_state_release_iclog(log, iclog, ticket); + spin_unlock(&log->l_icloglock); + + return error; +} + +static void +xlog_state_activate_iclog( + struct xlog_in_core *iclog, + int *iclogs_changed) +{ + ASSERT(list_empty_careful(&iclog->ic_callbacks)); + trace_xlog_iclog_activate(iclog, _RET_IP_); + + /* + * 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 (*iclogs_changed == 0 && + iclog->ic_header.h_num_logops == cpu_to_be32(XLOG_COVER_OPS)) { + *iclogs_changed = 1; + } else { + /* + * We have two dirty iclogs so start over. This could also be + * num of ops indicating this is not the dummy going out. + */ + *iclogs_changed = 2; + } + + iclog->ic_state = XLOG_STATE_ACTIVE; + iclog->ic_offset = 0; + 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; + iclog->ic_header.h_tail_lsn = 0; +} + +/* + * Loop through all iclogs and mark all iclogs currently marked DIRTY as + * ACTIVE after iclog I/O has completed. + */ +static void +xlog_state_activate_iclogs( + struct xlog *log, + int *iclogs_changed) +{ + struct xlog_in_core *iclog = log->l_iclog; + + do { + if (iclog->ic_state == XLOG_STATE_DIRTY) + xlog_state_activate_iclog(iclog, iclogs_changed); + /* + * The ordering of marking iclogs ACTIVE must be maintained, so + * an iclog doesn't become ACTIVE beyond one that is SYNCING. + */ + else if (iclog->ic_state != XLOG_STATE_ACTIVE) + break; + } while ((iclog = iclog->ic_next) != log->l_iclog); +} + +static int +xlog_covered_state( + int prev_state, + int iclogs_changed) +{ + /* + * We go to NEED for any non-covering writes. We go to NEED2 if we just + * wrote the first covering record (DONE). We go to IDLE if we just + * wrote the second covering record (DONE2) and remain in IDLE until a + * non-covering write occurs. + */ + switch (prev_state) { + case XLOG_STATE_COVER_IDLE: + if (iclogs_changed == 1) + return XLOG_STATE_COVER_IDLE; + fallthrough; + case XLOG_STATE_COVER_NEED: + case XLOG_STATE_COVER_NEED2: + break; + case XLOG_STATE_COVER_DONE: + if (iclogs_changed == 1) + return XLOG_STATE_COVER_NEED2; + break; + case XLOG_STATE_COVER_DONE2: + if (iclogs_changed == 1) + return XLOG_STATE_COVER_IDLE; + break; + default: + ASSERT(0); + } + + return XLOG_STATE_COVER_NEED; +} + +STATIC void +xlog_state_clean_iclog( + struct xlog *log, + struct xlog_in_core *dirty_iclog) +{ + int iclogs_changed = 0; + + trace_xlog_iclog_clean(dirty_iclog, _RET_IP_); + + dirty_iclog->ic_state = XLOG_STATE_DIRTY; + + xlog_state_activate_iclogs(log, &iclogs_changed); + wake_up_all(&dirty_iclog->ic_force_wait); + + if (iclogs_changed) { + log->l_covered_state = xlog_covered_state(log->l_covered_state, + iclogs_changed); + } +} + +STATIC xfs_lsn_t +xlog_get_lowest_lsn( + struct xlog *log) +{ + struct xlog_in_core *iclog = log->l_iclog; + xfs_lsn_t lowest_lsn = 0, lsn; + + do { + if (iclog->ic_state == XLOG_STATE_ACTIVE || + iclog->ic_state == XLOG_STATE_DIRTY) + continue; + + lsn = be64_to_cpu(iclog->ic_header.h_lsn); + if ((lsn && !lowest_lsn) || XFS_LSN_CMP(lsn, lowest_lsn) < 0) + lowest_lsn = lsn; + } while ((iclog = iclog->ic_next) != log->l_iclog); + + return lowest_lsn; +} + +/* + * Completion of a iclog IO does not imply that a transaction has completed, as + * transactions can be large enough to span many iclogs. We cannot change the + * tail of the log half way through a transaction as this may be the only + * transaction in the log and moving the tail to point to the middle of it + * will prevent recovery from finding the start of the transaction. Hence we + * should only update the last_sync_lsn if this iclog contains transaction + * completion callbacks on it. + * + * We have to do this before we drop the icloglock to ensure we are the only one + * that can update it. + * + * If we are moving the last_sync_lsn forwards, we also need to ensure we kick + * the reservation grant head pushing. This is due to the fact that the push + * target is bound by the current last_sync_lsn value. Hence if we have a large + * amount of log space bound up in this committing transaction then the + * last_sync_lsn value may be the limiting factor preventing tail pushing from + * freeing space in the log. Hence once we've updated the last_sync_lsn we + * should push the AIL to ensure the push target (and hence the grant head) is + * no longer bound by the old log head location and can move forwards and make + * progress again. + */ +static void +xlog_state_set_callback( + struct xlog *log, + struct xlog_in_core *iclog, + xfs_lsn_t header_lsn) +{ + trace_xlog_iclog_callback(iclog, _RET_IP_); + iclog->ic_state = XLOG_STATE_CALLBACK; + + ASSERT(XFS_LSN_CMP(atomic64_read(&log->l_last_sync_lsn), + header_lsn) <= 0); + + if (list_empty_careful(&iclog->ic_callbacks)) + return; + + atomic64_set(&log->l_last_sync_lsn, header_lsn); + xlog_grant_push_ail(log, 0); +} + +/* + * Return true if we need to stop processing, false to continue to the next + * iclog. The caller will need to run callbacks if the iclog is returned in the + * XLOG_STATE_CALLBACK state. + */ +static bool +xlog_state_iodone_process_iclog( + struct xlog *log, + struct xlog_in_core *iclog) +{ + xfs_lsn_t lowest_lsn; + xfs_lsn_t header_lsn; + + switch (iclog->ic_state) { + case XLOG_STATE_ACTIVE: + case XLOG_STATE_DIRTY: + /* + * Skip all iclogs in the ACTIVE & DIRTY states: + */ + return false; + case XLOG_STATE_DONE_SYNC: + /* + * Now that we have an iclog that is in the DONE_SYNC state, do + * one more check here to see if we have chased our tail around. + * If this is not the lowest lsn iclog, then we will leave it + * for another completion to process. + */ + header_lsn = be64_to_cpu(iclog->ic_header.h_lsn); + lowest_lsn = xlog_get_lowest_lsn(log); + if (lowest_lsn && XFS_LSN_CMP(lowest_lsn, header_lsn) < 0) + return false; + xlog_state_set_callback(log, iclog, header_lsn); + return false; + default: + /* + * Can only perform callbacks in order. Since this iclog is not + * in the DONE_SYNC state, we skip the rest and just try to + * clean up. + */ + return true; + } +} + +/* + * Loop over all the iclogs, running attached callbacks on them. Return true if + * we ran any callbacks, indicating that we dropped the icloglock. We don't need + * to handle transient shutdown state here at all because + * xlog_state_shutdown_callbacks() will be run to do the necessary shutdown + * cleanup of the callbacks. + */ +static bool +xlog_state_do_iclog_callbacks( + struct xlog *log) + __releases(&log->l_icloglock) + __acquires(&log->l_icloglock) +{ + struct xlog_in_core *first_iclog = log->l_iclog; + struct xlog_in_core *iclog = first_iclog; + bool ran_callback = false; + + do { + LIST_HEAD(cb_list); + + if (xlog_state_iodone_process_iclog(log, iclog)) + break; + if (iclog->ic_state != XLOG_STATE_CALLBACK) { + iclog = iclog->ic_next; + continue; + } + list_splice_init(&iclog->ic_callbacks, &cb_list); + spin_unlock(&log->l_icloglock); + + trace_xlog_iclog_callbacks_start(iclog, _RET_IP_); + xlog_cil_process_committed(&cb_list); + trace_xlog_iclog_callbacks_done(iclog, _RET_IP_); + ran_callback = true; + + spin_lock(&log->l_icloglock); + xlog_state_clean_iclog(log, iclog); + iclog = iclog->ic_next; + } while (iclog != first_iclog); + + return ran_callback; +} + + +/* + * Loop running iclog completion callbacks until there are no more iclogs in a + * state that can run callbacks. + */ +STATIC void +xlog_state_do_callback( + struct xlog *log) +{ + int flushcnt = 0; + int repeats = 0; + + spin_lock(&log->l_icloglock); + while (xlog_state_do_iclog_callbacks(log)) { + if (xlog_is_shutdown(log)) + break; + + if (++repeats > 5000) { + flushcnt += repeats; + repeats = 0; + xfs_warn(log->l_mp, + "%s: possible infinite loop (%d iterations)", + __func__, flushcnt); + } + } + + if (log->l_iclog->ic_state == XLOG_STATE_ACTIVE) + wake_up_all(&log->l_flush_wait); + + spin_unlock(&log->l_icloglock); +} + + +/* + * Finish transitioning this iclog to the dirty state. + * + * Callbacks could take time, so they are done outside the scope of the + * global state machine log lock. + */ +STATIC void +xlog_state_done_syncing( + struct xlog_in_core *iclog) +{ + struct xlog *log = iclog->ic_log; + + spin_lock(&log->l_icloglock); + ASSERT(atomic_read(&iclog->ic_refcnt) == 0); + trace_xlog_iclog_sync_done(iclog, _RET_IP_); + + /* + * If we got an error, either on the first buffer, or in the case of + * split log writes, on the second, we shut down the file system and + * no iclogs should ever be attempted to be written to disk again. + */ + if (!xlog_is_shutdown(log)) { + ASSERT(iclog->ic_state == XLOG_STATE_SYNCING); + 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. + */ + wake_up_all(&iclog->ic_write_wait); + spin_unlock(&log->l_icloglock); + xlog_state_do_callback(log); +} + +/* + * 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( + struct xlog *log, + int len, + struct xlog_in_core **iclogp, + struct xlog_ticket *ticket, + int *logoffsetp) +{ + int log_offset; + xlog_rec_header_t *head; + xlog_in_core_t *iclog; + +restart: + spin_lock(&log->l_icloglock); + if (xlog_is_shutdown(log)) { + spin_unlock(&log->l_icloglock); + return -EIO; + } + + iclog = log->l_iclog; + if (iclog->ic_state != XLOG_STATE_ACTIVE) { + XFS_STATS_INC(log->l_mp, xs_log_noiclogs); + + /* Wait for log writes to have flushed */ + xlog_wait(&log->l_flush_wait, &log->l_icloglock); + goto restart; + } + + head = &iclog->ic_header; + + atomic_inc(&iclog->ic_refcnt); /* prevents sync */ + log_offset = iclog->ic_offset; + + trace_xlog_iclog_get_space(iclog, _RET_IP_); + + /* 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; + 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)) { + int error = 0; + + xlog_state_switch_iclogs(log, iclog, iclog->ic_size); + + /* + * If we are 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)) + error = xlog_state_release_iclog(log, iclog, ticket); + spin_unlock(&log->l_icloglock); + if (error) + return error; + 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) + iclog->ic_offset += len; + else + 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; +} + +/* + * The first cnt-1 times a ticket goes 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. + */ +void +xfs_log_ticket_regrant( + struct xlog *log, + struct xlog_ticket *ticket) +{ + trace_xfs_log_ticket_regrant(log, ticket); + + if (ticket->t_cnt > 0) + ticket->t_cnt--; + + xlog_grant_sub_space(log, &log->l_reserve_head.grant, + ticket->t_curr_res); + xlog_grant_sub_space(log, &log->l_write_head.grant, + ticket->t_curr_res); + ticket->t_curr_res = ticket->t_unit_res; + + trace_xfs_log_ticket_regrant_sub(log, ticket); + + /* just return if we still have some of the pre-reserved space */ + if (!ticket->t_cnt) { + xlog_grant_add_space(log, &log->l_reserve_head.grant, + ticket->t_unit_res); + trace_xfs_log_ticket_regrant_exit(log, ticket); + + ticket->t_curr_res = ticket->t_unit_res; + } + + xfs_log_ticket_put(ticket); +} + +/* + * 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. + */ +void +xfs_log_ticket_ungrant( + struct xlog *log, + struct xlog_ticket *ticket) +{ + int bytes; + + trace_xfs_log_ticket_ungrant(log, ticket); + + if (ticket->t_cnt > 0) + ticket->t_cnt--; + + trace_xfs_log_ticket_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. + */ + bytes = ticket->t_curr_res; + if (ticket->t_cnt > 0) { + ASSERT(ticket->t_flags & XLOG_TIC_PERM_RESERV); + bytes += ticket->t_unit_res*ticket->t_cnt; + } + + xlog_grant_sub_space(log, &log->l_reserve_head.grant, bytes); + xlog_grant_sub_space(log, &log->l_write_head.grant, bytes); + + trace_xfs_log_ticket_ungrant_exit(log, ticket); + + xfs_log_space_wake(log->l_mp); + xfs_log_ticket_put(ticket); +} + +/* + * 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. + */ +void +xlog_state_switch_iclogs( + struct xlog *log, + struct xlog_in_core *iclog, + int eventual_size) +{ + ASSERT(iclog->ic_state == XLOG_STATE_ACTIVE); + assert_spin_locked(&log->l_icloglock); + trace_xlog_iclog_switch(iclog, _RET_IP_); + + 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 (log->l_iclog_roundoff > BBSIZE) { + uint32_t sunit_bb = BTOBB(log->l_iclog_roundoff); + log->l_curr_block = roundup(log->l_curr_block, sunit_bb); + } + + if (log->l_curr_block >= log->l_logBBsize) { + /* + * Rewind the current block before the cycle is bumped to make + * sure that the combined LSN never transiently moves forward + * when the log wraps to the next cycle. This is to support the + * unlocked sample of these fields from xlog_valid_lsn(). Most + * other cases should acquire l_icloglock. + */ + log->l_curr_block -= log->l_logBBsize; + ASSERT(log->l_curr_block >= 0); + smp_wmb(); + log->l_curr_cycle++; + if (log->l_curr_cycle == XLOG_HEADER_MAGIC_NUM) + log->l_curr_cycle++; + } + ASSERT(iclog == log->l_iclog); + log->l_iclog = iclog->ic_next; +} + +/* + * Force the iclog to disk and check if the iclog has been completed before + * xlog_force_iclog() returns. This can happen on synchronous (e.g. + * pmem) or fast async storage because we drop the icloglock to issue the IO. + * If completion has already occurred, tell the caller so that it can avoid an + * unnecessary wait on the iclog. + */ +static int +xlog_force_and_check_iclog( + struct xlog_in_core *iclog, + bool *completed) +{ + xfs_lsn_t lsn = be64_to_cpu(iclog->ic_header.h_lsn); + int error; + + *completed = false; + error = xlog_force_iclog(iclog); + if (error) + return error; + + /* + * If the iclog has already been completed and reused the header LSN + * will have been rewritten by completion + */ + if (be64_to_cpu(iclog->ic_header.h_lsn) != lsn) + *completed = true; + return 0; +} + +/* + * 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) +{ + struct xlog *log = mp->m_log; + struct xlog_in_core *iclog; + + XFS_STATS_INC(mp, xs_log_force); + trace_xfs_log_force(mp, 0, _RET_IP_); + + xlog_cil_force(log); + + spin_lock(&log->l_icloglock); + if (xlog_is_shutdown(log)) + goto out_error; + + iclog = log->l_iclog; + trace_xlog_iclog_force(iclog, _RET_IP_); + + if (iclog->ic_state == XLOG_STATE_DIRTY || + (iclog->ic_state == XLOG_STATE_ACTIVE && + atomic_read(&iclog->ic_refcnt) == 0 && iclog->ic_offset == 0)) { + /* + * 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. + */ + iclog = iclog->ic_prev; + } else if (iclog->ic_state == XLOG_STATE_ACTIVE) { + if (atomic_read(&iclog->ic_refcnt) == 0) { + /* We have exclusive access to this iclog. */ + bool completed; + + if (xlog_force_and_check_iclog(iclog, &completed)) + goto out_error; + + if (completed) + goto out_unlock; + } else { + /* + * Someone else is still writing to this iclog, so we + * need to ensure that when they release the iclog it + * gets synced immediately as we may be waiting on it. + */ + xlog_state_switch_iclogs(log, iclog, 0); + } + } + + /* + * The iclog we are about to wait on may contain the checkpoint pushed + * by the above xlog_cil_force() call, but it may not have been pushed + * to disk yet. Like the ACTIVE case above, we need to make sure caches + * are flushed when this iclog is written. + */ + if (iclog->ic_state == XLOG_STATE_WANT_SYNC) + iclog->ic_flags |= XLOG_ICL_NEED_FLUSH | XLOG_ICL_NEED_FUA; + + if (flags & XFS_LOG_SYNC) + return xlog_wait_on_iclog(iclog); +out_unlock: + spin_unlock(&log->l_icloglock); + return 0; +out_error: + spin_unlock(&log->l_icloglock); + return -EIO; +} + +/* + * Force the log to a specific LSN. + * + * If an iclog with that lsn can be found: + * 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 wait queue. All callers trying + * to force a given lsn to disk must wait on the queue 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 queue. + */ +static int +xlog_force_lsn( + struct xlog *log, + xfs_lsn_t lsn, + uint flags, + int *log_flushed, + bool already_slept) +{ + struct xlog_in_core *iclog; + bool completed; + + spin_lock(&log->l_icloglock); + if (xlog_is_shutdown(log)) + goto out_error; + + iclog = log->l_iclog; + while (be64_to_cpu(iclog->ic_header.h_lsn) != lsn) { + trace_xlog_iclog_force_lsn(iclog, _RET_IP_); + iclog = iclog->ic_next; + if (iclog == log->l_iclog) + goto out_unlock; + } + + switch (iclog->ic_state) { + case 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 || + iclog->ic_prev->ic_state == XLOG_STATE_SYNCING)) { + xlog_wait(&iclog->ic_prev->ic_write_wait, + &log->l_icloglock); + return -EAGAIN; + } + if (xlog_force_and_check_iclog(iclog, &completed)) + goto out_error; + if (log_flushed) + *log_flushed = 1; + if (completed) + goto out_unlock; + break; + case XLOG_STATE_WANT_SYNC: + /* + * This iclog may contain the checkpoint pushed by the + * xlog_cil_force_seq() call, but there are other writers still + * accessing it so it hasn't been pushed to disk yet. Like the + * ACTIVE case above, we need to make sure caches are flushed + * when this iclog is written. + */ + iclog->ic_flags |= XLOG_ICL_NEED_FLUSH | XLOG_ICL_NEED_FUA; + break; + default: + /* + * The entire checkpoint was written by the CIL force and is on + * its way to disk already. It will be stable when it + * completes, so we don't need to manipulate caches here at all. + * We just need to wait for completion if necessary. + */ + break; + } + + if (flags & XFS_LOG_SYNC) + return xlog_wait_on_iclog(iclog); +out_unlock: + spin_unlock(&log->l_icloglock); + return 0; +out_error: + spin_unlock(&log->l_icloglock); + return -EIO; +} + +/* + * Force the log to a specific checkpoint sequence. + * + * First force the CIL so that all the required changes have been flushed to the + * iclogs. If the CIL force completed it will return a commit LSN that indicates + * the iclog that needs to be flushed to stable storage. If the caller needs + * a synchronous log force, we will wait on the iclog with the LSN returned by + * xlog_cil_force_seq() to be completed. + */ +int +xfs_log_force_seq( + struct xfs_mount *mp, + xfs_csn_t seq, + uint flags, + int *log_flushed) +{ + struct xlog *log = mp->m_log; + xfs_lsn_t lsn; + int ret; + ASSERT(seq != 0); + + XFS_STATS_INC(mp, xs_log_force); + trace_xfs_log_force(mp, seq, _RET_IP_); + + lsn = xlog_cil_force_seq(log, seq); + if (lsn == NULLCOMMITLSN) + return 0; + + ret = xlog_force_lsn(log, lsn, flags, log_flushed, false); + if (ret == -EAGAIN) { + XFS_STATS_INC(mp, xs_log_force_sleep); + ret = xlog_force_lsn(log, lsn, flags, log_flushed, true); + } + return ret; +} + +/* + * 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)) + kmem_cache_free(xfs_log_ticket_cache, 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; +} + +/* + * Figure out the total log space unit (in bytes) that would be + * required for a log ticket. + */ +static int +xlog_calc_unit_res( + struct xlog *log, + int unit_bytes, + int *niclogs) +{ + int iclog_space; + uint num_headers; + + /* + * 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; + + /* roundoff padding for transaction data and one for commit record */ + unit_bytes += 2 * log->l_iclog_roundoff; + + if (niclogs) + *niclogs = num_headers; + return unit_bytes; +} + +int +xfs_log_calc_unit_res( + struct xfs_mount *mp, + int unit_bytes) +{ + return xlog_calc_unit_res(mp->m_log, unit_bytes, NULL); +} + +/* + * Allocate and initialise a new log ticket. + */ +struct xlog_ticket * +xlog_ticket_alloc( + struct xlog *log, + int unit_bytes, + int cnt, + bool permanent) +{ + struct xlog_ticket *tic; + int unit_res; + + tic = kmem_cache_zalloc(xfs_log_ticket_cache, GFP_NOFS | __GFP_NOFAIL); + + unit_res = xlog_calc_unit_res(log, unit_bytes, &tic->t_iclog_hdrs); + + atomic_set(&tic->t_ref, 1); + tic->t_task = current; + INIT_LIST_HEAD(&tic->t_queue); + tic->t_unit_res = unit_res; + tic->t_curr_res = unit_res; + tic->t_cnt = cnt; + tic->t_ocnt = cnt; + tic->t_tid = get_random_u32(); + if (permanent) + tic->t_flags |= XLOG_TIC_PERM_RESERV; + + return tic; +} + +#if defined(DEBUG) +/* + * 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. + * + * This check is run unlocked, so can give false positives. Rather than assert + * on failures, use a warn-once flag and a panic tag to allow the admin to + * determine if they want to panic the machine when such an error occurs. For + * debug kernels this will have the same effect as using an assert but, unlinke + * an assert, it can be turned off at runtime. + */ +STATIC void +xlog_verify_grant_tail( + struct xlog *log) +{ + int tail_cycle, tail_blocks; + int cycle, space; + + xlog_crack_grant_head(&log->l_write_head.grant, &cycle, &space); + xlog_crack_atomic_lsn(&log->l_tail_lsn, &tail_cycle, &tail_blocks); + if (tail_cycle != cycle) { + if (cycle - 1 != tail_cycle && + !test_and_set_bit(XLOG_TAIL_WARN, &log->l_opstate)) { + xfs_alert_tag(log->l_mp, XFS_PTAG_LOGRES, + "%s: cycle - 1 != tail_cycle", __func__); + } + + if (space > BBTOB(tail_blocks) && + !test_and_set_bit(XLOG_TAIL_WARN, &log->l_opstate)) { + xfs_alert_tag(log->l_mp, XFS_PTAG_LOGRES, + "%s: space > BBTOB(tail_blocks)", __func__); + } + } +} + +/* check if it will fit */ +STATIC void +xlog_verify_tail_lsn( + struct xlog *log, + struct xlog_in_core *iclog) +{ + xfs_lsn_t tail_lsn = be64_to_cpu(iclog->ic_header.h_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)) + xfs_emerg(log->l_mp, "%s: ran out of log space", __func__); + } else { + ASSERT(CYCLE_LSN(tail_lsn)+1 == log->l_prev_cycle); + + if (BLOCK_LSN(tail_lsn) == log->l_prev_block) + xfs_emerg(log->l_mp, "%s: tail wrapped", __func__); + + blocks = BLOCK_LSN(tail_lsn) - log->l_prev_block; + if (blocks < BTOBB(iclog->ic_offset) + 1) + xfs_emerg(log->l_mp, "%s: ran out of log space", __func__); + } +} + +/* + * 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( + struct xlog *log, + struct xlog_in_core *iclog, + int count) +{ + xlog_op_header_t *ophead; + xlog_in_core_t *icptr; + xlog_in_core_2_t *xhdr; + void *base_ptr, *ptr, *p; + ptrdiff_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++, icptr = icptr->ic_next) + ASSERT(icptr); + + if (icptr != log->l_iclog) + xfs_emerg(log->l_mp, "%s: corrupt iclog ring", __func__); + spin_unlock(&log->l_icloglock); + + /* check log magic numbers */ + if (iclog->ic_header.h_magicno != cpu_to_be32(XLOG_HEADER_MAGIC_NUM)) + xfs_emerg(log->l_mp, "%s: invalid magic num", __func__); + + base_ptr = ptr = &iclog->ic_header; + p = &iclog->ic_header; + for (ptr += BBSIZE; ptr < base_ptr + count; ptr += BBSIZE) { + if (*(__be32 *)ptr == cpu_to_be32(XLOG_HEADER_MAGIC_NUM)) + xfs_emerg(log->l_mp, "%s: unexpected magic num", + __func__); + } + + /* check fields */ + len = be32_to_cpu(iclog->ic_header.h_num_logops); + base_ptr = ptr = iclog->ic_datap; + ophead = ptr; + xhdr = iclog->ic_data; + for (i = 0; i < len; i++) { + ophead = ptr; + + /* clientid is only 1 byte */ + p = &ophead->oh_clientid; + field_offset = p - base_ptr; + if (field_offset & 0x1ff) { + clientid = ophead->oh_clientid; + } else { + idx = BTOBBT((void *)&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) { + xfs_warn(log->l_mp, + "%s: op %d invalid clientid %d op "PTR_FMT" offset 0x%lx", + __func__, i, clientid, ophead, + (unsigned long)field_offset); + } + + /* check length */ + p = &ophead->oh_len; + field_offset = p - base_ptr; + if (field_offset & 0x1ff) { + op_len = be32_to_cpu(ophead->oh_len); + } else { + idx = BTOBBT((void *)&ophead->oh_len - 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; + } +} +#endif + +/* + * Perform a forced shutdown on the log. + * + * This can be called from low level log code to trigger a shutdown, or from the + * high level mount shutdown code when the mount shuts down. + * + * Our main objectives here are to make sure that: + * a. if the shutdown was not due to a log IO error, flush the logs to + * disk. Anything modified after this is ignored. + * b. the log gets atomically marked 'XLOG_IO_ERROR' for all interested + * parties to find out. Nothing new gets queued after this is done. + * c. Tasks sleeping on log reservations, pinned objects and + * other resources get woken up. + * d. The mount is also marked as shut down so that log triggered shutdowns + * still behave the same as if they called xfs_forced_shutdown(). + * + * Return true if the shutdown cause was a log IO error and we actually shut the + * log down. + */ +bool +xlog_force_shutdown( + struct xlog *log, + uint32_t shutdown_flags) +{ + bool log_error = (shutdown_flags & SHUTDOWN_LOG_IO_ERROR); + + if (!log) + return false; + + /* + * Flush all the completed transactions to disk before marking the log + * being shut down. We need to do this first as shutting down the log + * before the force will prevent the log force from flushing the iclogs + * to disk. + * + * When we are in recovery, there are no transactions to flush, and + * we don't want to touch the log because we don't want to perturb the + * current head/tail for future recovery attempts. Hence we need to + * avoid a log force in this case. + * + * If we are shutting down due to a log IO error, then we must avoid + * trying to write the log as that may just result in more IO errors and + * an endless shutdown/force loop. + */ + if (!log_error && !xlog_in_recovery(log)) + xfs_log_force(log->l_mp, XFS_LOG_SYNC); + + /* + * Atomically set the shutdown state. If the shutdown state is already + * set, there someone else is performing the shutdown and so we are done + * here. This should never happen because we should only ever get called + * once by the first shutdown caller. + * + * Much of the log state machine transitions assume that shutdown state + * cannot change once they hold the log->l_icloglock. Hence we need to + * hold that lock here, even though we use the atomic test_and_set_bit() + * operation to set the shutdown state. + */ + spin_lock(&log->l_icloglock); + if (test_and_set_bit(XLOG_IO_ERROR, &log->l_opstate)) { + spin_unlock(&log->l_icloglock); + return false; + } + spin_unlock(&log->l_icloglock); + + /* + * If this log shutdown also sets the mount shutdown state, issue a + * shutdown warning message. + */ + if (!test_and_set_bit(XFS_OPSTATE_SHUTDOWN, &log->l_mp->m_opstate)) { + xfs_alert_tag(log->l_mp, XFS_PTAG_SHUTDOWN_LOGERROR, +"Filesystem has been shut down due to log error (0x%x).", + shutdown_flags); + xfs_alert(log->l_mp, +"Please unmount the filesystem and rectify the problem(s)."); + if (xfs_error_level >= XFS_ERRLEVEL_HIGH) + xfs_stack_trace(); + } + + /* + * We don't want anybody waiting for log reservations after this. That + * means we have to wake up everybody queued up on reserveq as well as + * writeq. 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 grant locks. + */ + xlog_grant_head_wake_all(&log->l_reserve_head); + xlog_grant_head_wake_all(&log->l_write_head); + + /* + * Wake up everybody waiting on xfs_log_force. Wake the CIL push first + * as if the log writes were completed. The abort handling in the log + * item committed callback functions will do this again under lock to + * avoid races. + */ + spin_lock(&log->l_cilp->xc_push_lock); + wake_up_all(&log->l_cilp->xc_start_wait); + wake_up_all(&log->l_cilp->xc_commit_wait); + spin_unlock(&log->l_cilp->xc_push_lock); + + spin_lock(&log->l_icloglock); + xlog_state_shutdown_callbacks(log); + spin_unlock(&log->l_icloglock); + + wake_up_var(&log->l_opstate); + return log_error; +} + +STATIC int +xlog_iclogs_empty( + struct xlog *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; +} + +/* + * Verify that an LSN stamped into a piece of metadata is valid. This is + * intended for use in read verifiers on v5 superblocks. + */ +bool +xfs_log_check_lsn( + struct xfs_mount *mp, + xfs_lsn_t lsn) +{ + struct xlog *log = mp->m_log; + bool valid; + + /* + * norecovery mode skips mount-time log processing and unconditionally + * resets the in-core LSN. We can't validate in this mode, but + * modifications are not allowed anyways so just return true. + */ + if (xfs_has_norecovery(mp)) + return true; + + /* + * Some metadata LSNs are initialized to NULL (e.g., the agfl). This is + * handled by recovery and thus safe to ignore here. + */ + if (lsn == NULLCOMMITLSN) + return true; + + valid = xlog_valid_lsn(mp->m_log, lsn); + + /* warn the user about what's gone wrong before verifier failure */ + if (!valid) { + spin_lock(&log->l_icloglock); + xfs_warn(mp, +"Corruption warning: Metadata has LSN (%d:%d) ahead of current LSN (%d:%d). " +"Please unmount and run xfs_repair (>= v4.3) to resolve.", + CYCLE_LSN(lsn), BLOCK_LSN(lsn), + log->l_curr_cycle, log->l_curr_block); + spin_unlock(&log->l_icloglock); + } + + return valid; +} + +/* + * Notify the log that we're about to start using a feature that is protected + * by a log incompat feature flag. This will prevent log covering from + * clearing those flags. + */ +void +xlog_use_incompat_feat( + struct xlog *log) +{ + down_read(&log->l_incompat_users); +} + +/* Notify the log that we've finished using log incompat features. */ +void +xlog_drop_incompat_feat( + struct xlog *log) +{ + up_read(&log->l_incompat_users); +} |