--- /dev/null
+/*
+ * Copyright (c) 2010 Red Hat, Inc. All Rights Reserved.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it would be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write the Free Software Foundation,
+ * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include "xfs.h"
+#include "xfs_fs.h"
+#include "xfs_types.h"
+#include "xfs_bit.h"
+#include "xfs_log.h"
+#include "xfs_inum.h"
+#include "xfs_trans.h"
+#include "xfs_trans_priv.h"
+#include "xfs_log_priv.h"
+#include "xfs_sb.h"
+#include "xfs_ag.h"
+#include "xfs_dir2.h"
+#include "xfs_dmapi.h"
+#include "xfs_mount.h"
+#include "xfs_error.h"
+#include "xfs_alloc.h"
+
+/*
+ * Perform initial CIL structure initialisation. If the CIL is not
+ * enabled in this filesystem, ensure the log->l_cilp is null so
+ * we can check this conditional to determine if we are doing delayed
+ * logging or not.
+ */
+int
+xlog_cil_init(
+ struct log *log)
+{
+ struct xfs_cil *cil;
+ struct xfs_cil_ctx *ctx;
+
+ log->l_cilp = NULL;
+ if (!(log->l_mp->m_flags & XFS_MOUNT_DELAYLOG))
+ return 0;
+
+ cil = kmem_zalloc(sizeof(*cil), KM_SLEEP|KM_MAYFAIL);
+ if (!cil)
+ return ENOMEM;
+
+ ctx = kmem_zalloc(sizeof(*ctx), KM_SLEEP|KM_MAYFAIL);
+ if (!ctx) {
+ kmem_free(cil);
+ return ENOMEM;
+ }
+
+ INIT_LIST_HEAD(&cil->xc_cil);
+ INIT_LIST_HEAD(&cil->xc_committing);
+ spin_lock_init(&cil->xc_cil_lock);
+ init_rwsem(&cil->xc_ctx_lock);
+ sv_init(&cil->xc_commit_wait, SV_DEFAULT, "cilwait");
+
+ INIT_LIST_HEAD(&ctx->committing);
+ INIT_LIST_HEAD(&ctx->busy_extents);
+ ctx->sequence = 1;
+ ctx->cil = cil;
+ cil->xc_ctx = ctx;
+
+ cil->xc_log = log;
+ log->l_cilp = cil;
+ return 0;
+}
+
+void
+xlog_cil_destroy(
+ struct log *log)
+{
+ if (!log->l_cilp)
+ return;
+
+ if (log->l_cilp->xc_ctx) {
+ if (log->l_cilp->xc_ctx->ticket)
+ xfs_log_ticket_put(log->l_cilp->xc_ctx->ticket);
+ kmem_free(log->l_cilp->xc_ctx);
+ }
+
+ ASSERT(list_empty(&log->l_cilp->xc_cil));
+ kmem_free(log->l_cilp);
+}
+
+/*
+ * Allocate a new ticket. Failing to get a new ticket makes it really hard to
+ * recover, so we don't allow failure here. Also, we allocate in a context that
+ * we don't want to be issuing transactions from, so we need to tell the
+ * allocation code this as well.
+ *
+ * We don't reserve any space for the ticket - we are going to steal whatever
+ * space we require from transactions as they commit. To ensure we reserve all
+ * the space required, we need to set the current reservation of the ticket to
+ * zero so that we know to steal the initial transaction overhead from the
+ * first transaction commit.
+ */
+static struct xlog_ticket *
+xlog_cil_ticket_alloc(
+ struct log *log)
+{
+ struct xlog_ticket *tic;
+
+ tic = xlog_ticket_alloc(log, 0, 1, XFS_TRANSACTION, 0,
+ KM_SLEEP|KM_NOFS);
+ tic->t_trans_type = XFS_TRANS_CHECKPOINT;
+
+ /*
+ * set the current reservation to zero so we know to steal the basic
+ * transaction overhead reservation from the first transaction commit.
+ */
+ tic->t_curr_res = 0;
+ return tic;
+}
+
+/*
+ * After the first stage of log recovery is done, we know where the head and
+ * tail of the log are. We need this log initialisation done before we can
+ * initialise the first CIL checkpoint context.
+ *
+ * Here we allocate a log ticket to track space usage during a CIL push. This
+ * ticket is passed to xlog_write() directly so that we don't slowly leak log
+ * space by failing to account for space used by log headers and additional
+ * region headers for split regions.
+ */
+void
+xlog_cil_init_post_recovery(
+ struct log *log)
+{
+ if (!log->l_cilp)
+ return;
+
+ log->l_cilp->xc_ctx->ticket = xlog_cil_ticket_alloc(log);
+ log->l_cilp->xc_ctx->sequence = 1;
+ log->l_cilp->xc_ctx->commit_lsn = xlog_assign_lsn(log->l_curr_cycle,
+ log->l_curr_block);
+}
+
+/*
+ * Insert the log item into the CIL and calculate the difference in space
+ * consumed by the item. Add the space to the checkpoint ticket and calculate
+ * if the change requires additional log metadata. If it does, take that space
+ * as well. Remove the amount of space we addded to the checkpoint ticket from
+ * the current transaction ticket so that the accounting works out correctly.
+ *
+ * If this is the first time the item is being placed into the CIL in this
+ * context, pin it so it can't be written to disk until the CIL is flushed to
+ * the iclog and the iclog written to disk.
+ */
+static void
+xlog_cil_insert(
+ struct log *log,
+ struct xlog_ticket *ticket,
+ struct xfs_log_item *item,
+ struct xfs_log_vec *lv)
+{
+ struct xfs_cil *cil = log->l_cilp;
+ struct xfs_log_vec *old = lv->lv_item->li_lv;
+ struct xfs_cil_ctx *ctx = cil->xc_ctx;
+ int len;
+ int diff_iovecs;
+ int iclog_space;
+
+ if (old) {
+ /* existing lv on log item, space used is a delta */
+ ASSERT(!list_empty(&item->li_cil));
+ ASSERT(old->lv_buf && old->lv_buf_len && old->lv_niovecs);
+
+ len = lv->lv_buf_len - old->lv_buf_len;
+ diff_iovecs = lv->lv_niovecs - old->lv_niovecs;
+ kmem_free(old->lv_buf);
+ kmem_free(old);
+ } else {
+ /* new lv, must pin the log item */
+ ASSERT(!lv->lv_item->li_lv);
+ ASSERT(list_empty(&item->li_cil));
+
+ len = lv->lv_buf_len;
+ diff_iovecs = lv->lv_niovecs;
+ IOP_PIN(lv->lv_item);
+
+ }
+ len += diff_iovecs * sizeof(xlog_op_header_t);
+
+ /* attach new log vector to log item */
+ lv->lv_item->li_lv = lv;
+
+ spin_lock(&cil->xc_cil_lock);
+ list_move_tail(&item->li_cil, &cil->xc_cil);
+ ctx->nvecs += diff_iovecs;
+
+ /*
+ * Now transfer enough transaction reservation to the context ticket
+ * for the checkpoint. The context ticket is special - the unit
+ * reservation has to grow as well as the current reservation as we
+ * steal from tickets so we can correctly determine the space used
+ * during the transaction commit.
+ */
+ if (ctx->ticket->t_curr_res == 0) {
+ /* first commit in checkpoint, steal the header reservation */
+ ASSERT(ticket->t_curr_res >= ctx->ticket->t_unit_res + len);
+ ctx->ticket->t_curr_res = ctx->ticket->t_unit_res;
+ ticket->t_curr_res -= ctx->ticket->t_unit_res;
+ }
+
+ /* do we need space for more log record headers? */
+ iclog_space = log->l_iclog_size - log->l_iclog_hsize;
+ if (len > 0 && (ctx->space_used / iclog_space !=
+ (ctx->space_used + len) / iclog_space)) {
+ int hdrs;
+
+ hdrs = (len + iclog_space - 1) / iclog_space;
+ /* need to take into account split region headers, too */
+ hdrs *= log->l_iclog_hsize + sizeof(struct xlog_op_header);
+ ctx->ticket->t_unit_res += hdrs;
+ ctx->ticket->t_curr_res += hdrs;
+ ticket->t_curr_res -= hdrs;
+ ASSERT(ticket->t_curr_res >= len);
+ }
+ ticket->t_curr_res -= len;
+ ctx->space_used += len;
+
+ spin_unlock(&cil->xc_cil_lock);
+}
+
+/*
+ * Format log item into a flat buffers
+ *
+ * For delayed logging, we need to hold a formatted buffer containing all the
+ * changes on the log item. This enables us to relog the item in memory and
+ * write it out asynchronously without needing to relock the object that was
+ * modified at the time it gets written into the iclog.
+ *
+ * This function builds a vector for the changes in each log item in the
+ * transaction. It then works out the length of the buffer needed for each log
+ * item, allocates them and formats the vector for the item into the buffer.
+ * The buffer is then attached to the log item are then inserted into the
+ * Committed Item List for tracking until the next checkpoint is written out.
+ *
+ * We don't set up region headers during this process; we simply copy the
+ * regions into the flat buffer. We can do this because we still have to do a
+ * formatting step to write the regions into the iclog buffer. Writing the
+ * ophdrs during the iclog write means that we can support splitting large
+ * regions across iclog boundares without needing a change in the format of the
+ * item/region encapsulation.
+ *
+ * Hence what we need to do now is change the rewrite the vector array to point
+ * to the copied region inside the buffer we just allocated. This allows us to
+ * format the regions into the iclog as though they are being formatted
+ * directly out of the objects themselves.
+ */
+static void
+xlog_cil_format_items(
+ struct log *log,
+ struct xfs_log_vec *log_vector,
+ struct xlog_ticket *ticket,
+ xfs_lsn_t *start_lsn)
+{
+ struct xfs_log_vec *lv;
+
+ if (start_lsn)
+ *start_lsn = log->l_cilp->xc_ctx->sequence;
+
+ ASSERT(log_vector);
+ for (lv = log_vector; lv; lv = lv->lv_next) {
+ void *ptr;
+ int index;
+ int len = 0;
+
+ /* build the vector array and calculate it's length */
+ IOP_FORMAT(lv->lv_item, lv->lv_iovecp);
+ for (index = 0; index < lv->lv_niovecs; index++)
+ len += lv->lv_iovecp[index].i_len;
+
+ lv->lv_buf_len = len;
+ lv->lv_buf = kmem_zalloc(lv->lv_buf_len, KM_SLEEP|KM_NOFS);
+ ptr = lv->lv_buf;
+
+ for (index = 0; index < lv->lv_niovecs; index++) {
+ struct xfs_log_iovec *vec = &lv->lv_iovecp[index];
+
+ memcpy(ptr, vec->i_addr, vec->i_len);
+ vec->i_addr = ptr;
+ ptr += vec->i_len;
+ }
+ ASSERT(ptr == lv->lv_buf + lv->lv_buf_len);
+
+ xlog_cil_insert(log, ticket, lv->lv_item, lv);
+ }
+}
+
+static void
+xlog_cil_free_logvec(
+ struct xfs_log_vec *log_vector)
+{
+ struct xfs_log_vec *lv;
+
+ for (lv = log_vector; lv; ) {
+ struct xfs_log_vec *next = lv->lv_next;
+ kmem_free(lv->lv_buf);
+ kmem_free(lv);
+ lv = next;
+ }
+}
+
+/*
+ * Commit a transaction with the given vector to the Committed Item List.
+ *
+ * To do this, we need to format the item, pin it in memory if required and
+ * account for the space used by the transaction. Once we have done that we
+ * need to release the unused reservation for the transaction, attach the
+ * transaction to the checkpoint context so we carry the busy extents through
+ * to checkpoint completion, and then unlock all the items in the transaction.
+ *
+ * For more specific information about the order of operations in
+ * xfs_log_commit_cil() please refer to the comments in
+ * xfs_trans_commit_iclog().
+ */
+int
+xfs_log_commit_cil(
+ struct xfs_mount *mp,
+ struct xfs_trans *tp,
+ struct xfs_log_vec *log_vector,
+ xfs_lsn_t *commit_lsn,
+ int flags)
+{
+ struct log *log = mp->m_log;
+ int log_flags = 0;
+
+ if (flags & XFS_TRANS_RELEASE_LOG_RES)
+ log_flags = XFS_LOG_REL_PERM_RESERV;
+
+ if (XLOG_FORCED_SHUTDOWN(log)) {
+ xlog_cil_free_logvec(log_vector);
+ return XFS_ERROR(EIO);
+ }
+
+ /* lock out background commit */
+ down_read(&log->l_cilp->xc_ctx_lock);
+ xlog_cil_format_items(log, log_vector, tp->t_ticket, commit_lsn);
+
+ /* check we didn't blow the reservation */
+ if (tp->t_ticket->t_curr_res < 0)
+ xlog_print_tic_res(log->l_mp, tp->t_ticket);
+
+ /* attach the transaction to the CIL if it has any busy extents */
+ if (!list_empty(&tp->t_busy)) {
+ spin_lock(&log->l_cilp->xc_cil_lock);
+ list_splice_init(&tp->t_busy,
+ &log->l_cilp->xc_ctx->busy_extents);
+ spin_unlock(&log->l_cilp->xc_cil_lock);
+ }
+
+ tp->t_commit_lsn = *commit_lsn;
+ xfs_log_done(mp, tp->t_ticket, NULL, log_flags);
+ xfs_trans_unreserve_and_mod_sb(tp);
+
+ /* background commit is allowed again */
+ up_read(&log->l_cilp->xc_ctx_lock);
+ return 0;
+}
+
+/*
+ * Mark all items committed and clear busy extents. We free the log vector
+ * chains in a separate pass so that we unpin the log items as quickly as
+ * possible.
+ */
+static void
+xlog_cil_committed(
+ void *args,
+ int abort)
+{
+ struct xfs_cil_ctx *ctx = args;
+ struct xfs_log_vec *lv;
+ int abortflag = abort ? XFS_LI_ABORTED : 0;
+ struct xfs_busy_extent *busyp, *n;
+
+ /* unpin all the log items */
+ for (lv = ctx->lv_chain; lv; lv = lv->lv_next ) {
+ xfs_trans_item_committed(lv->lv_item, ctx->start_lsn,
+ abortflag);
+ }
+
+ list_for_each_entry_safe(busyp, n, &ctx->busy_extents, list)
+ xfs_alloc_busy_clear(ctx->cil->xc_log->l_mp, busyp);
+
+ spin_lock(&ctx->cil->xc_cil_lock);
+ list_del(&ctx->committing);
+ spin_unlock(&ctx->cil->xc_cil_lock);
+
+ xlog_cil_free_logvec(ctx->lv_chain);
+ kmem_free(ctx);
+}
+
+/*
+ * Push the Committed Item List to the log. If the push_now flag is not set,
+ * then it is a background flush and so we can chose to ignore it.
+ */
+int
+xlog_cil_push(
+ struct log *log,
+ int push_now)
+{
+ struct xfs_cil *cil = log->l_cilp;
+ struct xfs_log_vec *lv;
+ struct xfs_cil_ctx *ctx;
+ struct xfs_cil_ctx *new_ctx;
+ struct xlog_in_core *commit_iclog;
+ struct xlog_ticket *tic;
+ int num_lv;
+ int num_iovecs;
+ int len;
+ int error = 0;
+ struct xfs_trans_header thdr;
+ struct xfs_log_iovec lhdr;
+ struct xfs_log_vec lvhdr = { NULL };
+ xfs_lsn_t commit_lsn;
+
+ if (!cil)
+ return 0;
+
+ /* XXX: don't sleep for background? */
+ new_ctx = kmem_zalloc(sizeof(*new_ctx), KM_SLEEP|KM_NOFS);
+ new_ctx->ticket = xlog_cil_ticket_alloc(log);
+
+ /* lock out transaction commit */
+ down_write(&cil->xc_ctx_lock);
+ ctx = cil->xc_ctx;
+
+ /* check if we've anything to push */
+ if (list_empty(&cil->xc_cil))
+ goto out_skip;
+
+ /*
+ * pull all the log vectors off the items in the CIL, and
+ * remove the items from the CIL. We don't need the CIL lock
+ * here because it's only needed on the transaction commit
+ * side which is currently locked out by the flush lock.
+ */
+ lv = NULL;
+ num_lv = 0;
+ num_iovecs = 0;
+ len = 0;
+ while (!list_empty(&cil->xc_cil)) {
+ struct xfs_log_item *item;
+ int i;
+
+ item = list_first_entry(&cil->xc_cil,
+ struct xfs_log_item, li_cil);
+ list_del_init(&item->li_cil);
+ if (!ctx->lv_chain)
+ ctx->lv_chain = item->li_lv;
+ else
+ lv->lv_next = item->li_lv;
+ lv = item->li_lv;
+ item->li_lv = NULL;
+
+ num_lv++;
+ num_iovecs += lv->lv_niovecs;
+ for (i = 0; i < lv->lv_niovecs; i++)
+ len += lv->lv_iovecp[i].i_len;
+ }
+
+ /*
+ * initialise the new context and attach it to the CIL. Then attach
+ * the current context to the CIL committing lsit so it can be found
+ * during log forces to extract the commit lsn of the sequence that
+ * needs to be forced.
+ */
+ INIT_LIST_HEAD(&new_ctx->committing);
+ INIT_LIST_HEAD(&new_ctx->busy_extents);
+ new_ctx->sequence = ctx->sequence + 1;
+ new_ctx->cil = cil;
+ cil->xc_ctx = new_ctx;
+
+ /*
+ * The switch is now done, so we can drop the context lock and move out
+ * of a shared context. We can't just go straight to the commit record,
+ * though - we need to synchronise with previous and future commits so
+ * that the commit records are correctly ordered in the log to ensure
+ * that we process items during log IO completion in the correct order.
+ *
+ * For example, if we get an EFI in one checkpoint and the EFD in the
+ * next (e.g. due to log forces), we do not want the checkpoint with
+ * the EFD to be committed before the checkpoint with the EFI. Hence
+ * we must strictly order the commit records of the checkpoints so
+ * that: a) the checkpoint callbacks are attached to the iclogs in the
+ * correct order; and b) the checkpoints are replayed in correct order
+ * in log recovery.
+ *
+ * Hence we need to add this context to the committing context list so
+ * that higher sequences will wait for us to write out a commit record
+ * before they do.
+ */
+ spin_lock(&cil->xc_cil_lock);
+ list_add(&ctx->committing, &cil->xc_committing);
+ spin_unlock(&cil->xc_cil_lock);
+ up_write(&cil->xc_ctx_lock);
+
+ /*
+ * Build a checkpoint transaction header and write it to the log to
+ * begin the transaction. We need to account for the space used by the
+ * transaction header here as it is not accounted for in xlog_write().
+ *
+ * The LSN we need to pass to the log items on transaction commit is
+ * the LSN reported by the first log vector write. If we use the commit
+ * record lsn then we can move the tail beyond the grant write head.
+ */
+ tic = ctx->ticket;
+ thdr.th_magic = XFS_TRANS_HEADER_MAGIC;
+ thdr.th_type = XFS_TRANS_CHECKPOINT;
+ thdr.th_tid = tic->t_tid;
+ thdr.th_num_items = num_iovecs;
+ lhdr.i_addr = (xfs_caddr_t)&thdr;
+ lhdr.i_len = sizeof(xfs_trans_header_t);
+ lhdr.i_type = XLOG_REG_TYPE_TRANSHDR;
+ tic->t_curr_res -= lhdr.i_len + sizeof(xlog_op_header_t);
+
+ lvhdr.lv_niovecs = 1;
+ lvhdr.lv_iovecp = &lhdr;
+ lvhdr.lv_next = ctx->lv_chain;
+
+ error = xlog_write(log, &lvhdr, tic, &ctx->start_lsn, NULL, 0);
+ if (error)
+ goto out_abort;
+
+ /*
+ * now that we've written the checkpoint into the log, strictly
+ * order the commit records so replay will get them in the right order.
+ */
+restart:
+ spin_lock(&cil->xc_cil_lock);
+ list_for_each_entry(new_ctx, &cil->xc_committing, committing) {
+ /*
+ * Higher sequences will wait for this one so skip them.
+ * Don't wait for own own sequence, either.
+ */
+ if (new_ctx->sequence >= ctx->sequence)
+ continue;
+ if (!new_ctx->commit_lsn) {
+ /*
+ * It is still being pushed! Wait for the push to
+ * complete, then start again from the beginning.
+ */
+ sv_wait(&cil->xc_commit_wait, 0, &cil->xc_cil_lock, 0);
+ goto restart;
+ }
+ }
+ spin_unlock(&cil->xc_cil_lock);
+
+ commit_lsn = xfs_log_done(log->l_mp, tic, &commit_iclog, 0);
+ if (error || commit_lsn == -1)
+ goto out_abort;
+
+ /* attach all the transactions w/ busy extents to iclog */
+ ctx->log_cb.cb_func = xlog_cil_committed;
+ ctx->log_cb.cb_arg = ctx;
+ error = xfs_log_notify(log->l_mp, commit_iclog, &ctx->log_cb);
+ if (error)
+ goto out_abort;
+
+ /*
+ * now the checkpoint commit is complete and we've attached the
+ * callbacks to the iclog we can assign the commit LSN to the context
+ * and wake up anyone who is waiting for the commit to complete.
+ */
+ spin_lock(&cil->xc_cil_lock);
+ ctx->commit_lsn = commit_lsn;
+ sv_broadcast(&cil->xc_commit_wait);
+ spin_unlock(&cil->xc_cil_lock);
+
+ /* release the hounds! */
+ return xfs_log_release_iclog(log->l_mp, commit_iclog);
+
+out_skip:
+ up_write(&cil->xc_ctx_lock);
+ xfs_log_ticket_put(new_ctx->ticket);
+ kmem_free(new_ctx);
+ return 0;
+
+out_abort:
+ xlog_cil_committed(ctx, XFS_LI_ABORTED);
+ return XFS_ERROR(EIO);
+}
+
+/*
+ * Conditionally push the CIL based on the sequence passed in.
+ *
+ * We only need to push if we haven't already pushed the sequence
+ * number given. Hence the only time we will trigger a push here is
+ * if the push sequence is the same as the current context.
+ *
+ * We return the current commit lsn to allow the callers to determine if a
+ * iclog flush is necessary following this call.
+ *
+ * XXX: Initially, just push the CIL unconditionally and return whatever
+ * commit lsn is there. It'll be empty, so this is broken for now.
+ */
+xfs_lsn_t
+xlog_cil_push_lsn(
+ struct log *log,
+ xfs_lsn_t push_seq)
+{
+ struct xfs_cil *cil = log->l_cilp;
+ struct xfs_cil_ctx *ctx;
+ xfs_lsn_t commit_lsn = NULLCOMMITLSN;
+
+restart:
+ down_write(&cil->xc_ctx_lock);
+ ASSERT(push_seq <= cil->xc_ctx->sequence);
+
+ /* check to see if we need to force out the current context */
+ if (push_seq == cil->xc_ctx->sequence) {
+ up_write(&cil->xc_ctx_lock);
+ xlog_cil_push(log, 1);
+ goto restart;
+ }
+
+ /*
+ * See if we can find a previous sequence still committing.
+ * We can drop the flush lock as soon as we have the cil lock
+ * because we are now only comparing contexts protected by
+ * the cil lock.
+ *
+ * We need to wait for all previous sequence commits to complete
+ * before allowing the force of push_seq to go ahead. Hence block
+ * on commits for those as well.
+ */
+ spin_lock(&cil->xc_cil_lock);
+ up_write(&cil->xc_ctx_lock);
+ list_for_each_entry(ctx, &cil->xc_committing, committing) {
+ if (ctx->sequence > push_seq)
+ continue;
+ if (!ctx->commit_lsn) {
+ /*
+ * It is still being pushed! Wait for the push to
+ * complete, then start again from the beginning.
+ */
+ sv_wait(&cil->xc_commit_wait, 0, &cil->xc_cil_lock, 0);
+ goto restart;
+ }
+ if (ctx->sequence != push_seq)
+ continue;
+ /* found it! */
+ commit_lsn = ctx->commit_lsn;
+ }
+ spin_unlock(&cil->xc_cil_lock);
+ return commit_lsn;
+}
git.openpandora.org / pandora-kernel.git / commitdiff