--- /dev/null
+/*
+ * linux/fs/jbd2/commit.c
+ *
+ * Written by Stephen C. Tweedie <sct@redhat.com>, 1998
+ *
+ * Copyright 1998 Red Hat corp --- All Rights Reserved
+ *
+ * This file is part of the Linux kernel and is made available under
+ * the terms of the GNU General Public License, version 2, or at your
+ * option, any later version, incorporated herein by reference.
+ *
+ * Journal commit routines for the generic filesystem journaling code;
+ * part of the ext2fs journaling system.
+ */
+
+#include <linux/time.h>
+#include <linux/fs.h>
+#include <linux/jbd2.h>
+#include <linux/errno.h>
+#include <linux/slab.h>
+#include <linux/mm.h>
+#include <linux/pagemap.h>
+#include <linux/jiffies.h>
+#include <linux/crc32.h>
+#include <linux/writeback.h>
+#include <linux/backing-dev.h>
+#include <linux/bio.h>
+#include <linux/blkdev.h>
+#include <linux/bitops.h>
+#include <trace/events/jbd2.h>
+
+/*
+ * IO end handler for temporary buffer_heads handling writes to the journal.
+ */
+static void journal_end_buffer_io_sync(struct buffer_head *bh, int uptodate)
+{
+ struct buffer_head *orig_bh = bh->b_private;
+
+ BUFFER_TRACE(bh, "");
+ if (uptodate)
+ set_buffer_uptodate(bh);
+ else
+ clear_buffer_uptodate(bh);
+ if (orig_bh) {
+ clear_bit_unlock(BH_Shadow, &orig_bh->b_state);
+ smp_mb__after_atomic();
+ wake_up_bit(&orig_bh->b_state, BH_Shadow);
+ }
+ unlock_buffer(bh);
+}
+
+/*
+ * When an ext4 file is truncated, it is possible that some pages are not
+ * successfully freed, because they are attached to a committing transaction.
+ * After the transaction commits, these pages are left on the LRU, with no
+ * ->mapping, and with attached buffers. These pages are trivially reclaimable
+ * by the VM, but their apparent absence upsets the VM accounting, and it makes
+ * the numbers in /proc/meminfo look odd.
+ *
+ * So here, we have a buffer which has just come off the forget list. Look to
+ * see if we can strip all buffers from the backing page.
+ *
+ * Called under lock_journal(), and possibly under journal_datalist_lock. The
+ * caller provided us with a ref against the buffer, and we drop that here.
+ */
+static void release_buffer_page(struct buffer_head *bh)
+{
+ struct page *page;
+
+ if (buffer_dirty(bh))
+ goto nope;
+ if (atomic_read(&bh->b_count) != 1)
+ goto nope;
+ page = bh->b_page;
+ if (!page)
+ goto nope;
+ if (page->mapping)
+ goto nope;
+
+ /* OK, it's a truncated page */
+ if (!trylock_page(page))
+ goto nope;
+
+ page_cache_get(page);
+ __brelse(bh);
+ try_to_free_buffers(page);
+ unlock_page(page);
+ page_cache_release(page);
+ return;
+
+nope:
+ __brelse(bh);
+}
+
+static void jbd2_commit_block_csum_set(journal_t *j, struct buffer_head *bh)
+{
+ struct commit_header *h;
+ __u32 csum;
+
+ if (!jbd2_journal_has_csum_v2or3(j))
+ return;
+
+ h = (struct commit_header *)(bh->b_data);
+ h->h_chksum_type = 0;
+ h->h_chksum_size = 0;
+ h->h_chksum[0] = 0;
+ csum = jbd2_chksum(j, j->j_csum_seed, bh->b_data, j->j_blocksize);
+ h->h_chksum[0] = cpu_to_be32(csum);
+}
+
+/*
+ * Done it all: now submit the commit record. We should have
+ * cleaned up our previous buffers by now, so if we are in abort
+ * mode we can now just skip the rest of the journal write
+ * entirely.
+ *
+ * Returns 1 if the journal needs to be aborted or 0 on success
+ */
+static int journal_submit_commit_record(journal_t *journal,
+ transaction_t *commit_transaction,
+ struct buffer_head **cbh,
+ __u32 crc32_sum)
+{
+ struct commit_header *tmp;
+ struct buffer_head *bh;
+ int ret;
+ struct timespec now = current_kernel_time();
+
+ *cbh = NULL;
+
+ if (is_journal_aborted(journal))
+ return 0;
+
+ bh = jbd2_journal_get_descriptor_buffer(journal);
+ if (!bh)
+ return 1;
+
+ tmp = (struct commit_header *)bh->b_data;
+ tmp->h_magic = cpu_to_be32(JBD2_MAGIC_NUMBER);
+ tmp->h_blocktype = cpu_to_be32(JBD2_COMMIT_BLOCK);
+ tmp->h_sequence = cpu_to_be32(commit_transaction->t_tid);
+ tmp->h_commit_sec = cpu_to_be64(now.tv_sec);
+ tmp->h_commit_nsec = cpu_to_be32(now.tv_nsec);
+
+ if (JBD2_HAS_COMPAT_FEATURE(journal,
+ JBD2_FEATURE_COMPAT_CHECKSUM)) {
+ tmp->h_chksum_type = JBD2_CRC32_CHKSUM;
+ tmp->h_chksum_size = JBD2_CRC32_CHKSUM_SIZE;
+ tmp->h_chksum[0] = cpu_to_be32(crc32_sum);
+ }
+ jbd2_commit_block_csum_set(journal, bh);
+
+ BUFFER_TRACE(bh, "submit commit block");
+ lock_buffer(bh);
+ clear_buffer_dirty(bh);
+ set_buffer_uptodate(bh);
+ bh->b_end_io = journal_end_buffer_io_sync;
+
+ if (journal->j_flags & JBD2_BARRIER &&
+ !JBD2_HAS_INCOMPAT_FEATURE(journal,
+ JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT))
+ ret = submit_bh(WRITE_SYNC | WRITE_FLUSH_FUA, bh);
+ else
+ ret = submit_bh(WRITE_SYNC, bh);
+
+ *cbh = bh;
+ return ret;
+}
+
+/*
+ * This function along with journal_submit_commit_record
+ * allows to write the commit record asynchronously.
+ */
+static int journal_wait_on_commit_record(journal_t *journal,
+ struct buffer_head *bh)
+{
+ int ret = 0;
+
+ clear_buffer_dirty(bh);
+ wait_on_buffer(bh);
+
+ if (unlikely(!buffer_uptodate(bh)))
+ ret = -EIO;
+ put_bh(bh); /* One for getblk() */
+
+ return ret;
+}
+
+/*
+ * write the filemap data using writepage() address_space_operations.
+ * We don't do block allocation here even for delalloc. We don't
+ * use writepages() because with dealyed allocation we may be doing
+ * block allocation in writepages().
+ */
+static int journal_submit_inode_data_buffers(struct address_space *mapping)
+{
+ int ret;
+ struct writeback_control wbc = {
+ .sync_mode = WB_SYNC_ALL,
+ .nr_to_write = mapping->nrpages * 2,
+ .range_start = 0,
+ .range_end = i_size_read(mapping->host),
+ };
+
+ ret = generic_writepages(mapping, &wbc);
+ return ret;
+}
+
+/*
+ * Submit all the data buffers of inode associated with the transaction to
+ * disk.
+ *
+ * We are in a committing transaction. Therefore no new inode can be added to
+ * our inode list. We use JI_COMMIT_RUNNING flag to protect inode we currently
+ * operate on from being released while we write out pages.
+ */
+static int journal_submit_data_buffers(journal_t *journal,
+ transaction_t *commit_transaction)
+{
+ struct jbd2_inode *jinode;
+ int err, ret = 0;
+ struct address_space *mapping;
+
+ spin_lock(&journal->j_list_lock);
+ list_for_each_entry(jinode, &commit_transaction->t_inode_list, i_list) {
+ mapping = jinode->i_vfs_inode->i_mapping;
+ set_bit(__JI_COMMIT_RUNNING, &jinode->i_flags);
+ spin_unlock(&journal->j_list_lock);
+ /*
+ * submit the inode data buffers. We use writepage
+ * instead of writepages. Because writepages can do
+ * block allocation with delalloc. We need to write
+ * only allocated blocks here.
+ */
+ trace_jbd2_submit_inode_data(jinode->i_vfs_inode);
+ err = journal_submit_inode_data_buffers(mapping);
+ if (!ret)
+ ret = err;
+ spin_lock(&journal->j_list_lock);
+ J_ASSERT(jinode->i_transaction == commit_transaction);
+ clear_bit(__JI_COMMIT_RUNNING, &jinode->i_flags);
+ smp_mb__after_atomic();
+ wake_up_bit(&jinode->i_flags, __JI_COMMIT_RUNNING);
+ }
+ spin_unlock(&journal->j_list_lock);
+ return ret;
+}
+
+/*
+ * Wait for data submitted for writeout, refile inodes to proper
+ * transaction if needed.
+ *
+ */
+static int journal_finish_inode_data_buffers(journal_t *journal,
+ transaction_t *commit_transaction)
+{
+ struct jbd2_inode *jinode, *next_i;
+ int err, ret = 0;
+
+ /* For locking, see the comment in journal_submit_data_buffers() */
+ spin_lock(&journal->j_list_lock);
+ list_for_each_entry(jinode, &commit_transaction->t_inode_list, i_list) {
+ set_bit(__JI_COMMIT_RUNNING, &jinode->i_flags);
+ spin_unlock(&journal->j_list_lock);
+ err = filemap_fdatawait(jinode->i_vfs_inode->i_mapping);
+ if (err) {
+ /*
+ * Because AS_EIO is cleared by
+ * filemap_fdatawait_range(), set it again so
+ * that user process can get -EIO from fsync().
+ */
+ set_bit(AS_EIO,
+ &jinode->i_vfs_inode->i_mapping->flags);
+
+ if (!ret)
+ ret = err;
+ }
+ spin_lock(&journal->j_list_lock);
+ clear_bit(__JI_COMMIT_RUNNING, &jinode->i_flags);
+ smp_mb__after_atomic();
+ wake_up_bit(&jinode->i_flags, __JI_COMMIT_RUNNING);
+ }
+
+ /* Now refile inode to proper lists */
+ list_for_each_entry_safe(jinode, next_i,
+ &commit_transaction->t_inode_list, i_list) {
+ list_del(&jinode->i_list);
+ if (jinode->i_next_transaction) {
+ jinode->i_transaction = jinode->i_next_transaction;
+ jinode->i_next_transaction = NULL;
+ list_add(&jinode->i_list,
+ &jinode->i_transaction->t_inode_list);
+ } else {
+ jinode->i_transaction = NULL;
+ }
+ }
+ spin_unlock(&journal->j_list_lock);
+
+ return ret;
+}
+
+static __u32 jbd2_checksum_data(__u32 crc32_sum, struct buffer_head *bh)
+{
+ struct page *page = bh->b_page;
+ char *addr;
+ __u32 checksum;
+
+ addr = kmap_atomic(page);
+ checksum = crc32_be(crc32_sum,
+ (void *)(addr + offset_in_page(bh->b_data)), bh->b_size);
+ kunmap_atomic(addr);
+
+ return checksum;
+}
+
+static void write_tag_block(journal_t *j, journal_block_tag_t *tag,
+ unsigned long long block)
+{
+ tag->t_blocknr = cpu_to_be32(block & (u32)~0);
+ if (JBD2_HAS_INCOMPAT_FEATURE(j, JBD2_FEATURE_INCOMPAT_64BIT))
+ tag->t_blocknr_high = cpu_to_be32((block >> 31) >> 1);
+}
+
+static void jbd2_descr_block_csum_set(journal_t *j,
+ struct buffer_head *bh)
+{
+ struct jbd2_journal_block_tail *tail;
+ __u32 csum;
+
+ if (!jbd2_journal_has_csum_v2or3(j))
+ return;
+
+ tail = (struct jbd2_journal_block_tail *)(bh->b_data + j->j_blocksize -
+ sizeof(struct jbd2_journal_block_tail));
+ tail->t_checksum = 0;
+ csum = jbd2_chksum(j, j->j_csum_seed, bh->b_data, j->j_blocksize);
+ tail->t_checksum = cpu_to_be32(csum);
+}
+
+static void jbd2_block_tag_csum_set(journal_t *j, journal_block_tag_t *tag,
+ struct buffer_head *bh, __u32 sequence)
+{
+ journal_block_tag3_t *tag3 = (journal_block_tag3_t *)tag;
+ struct page *page = bh->b_page;
+ __u8 *addr;
+ __u32 csum32;
+ __be32 seq;
+
+ if (!jbd2_journal_has_csum_v2or3(j))
+ return;
+
+ seq = cpu_to_be32(sequence);
+ addr = kmap_atomic(page);
+ csum32 = jbd2_chksum(j, j->j_csum_seed, (__u8 *)&seq, sizeof(seq));
+ csum32 = jbd2_chksum(j, csum32, addr + offset_in_page(bh->b_data),
+ bh->b_size);
+ kunmap_atomic(addr);
+
+ if (JBD2_HAS_INCOMPAT_FEATURE(j, JBD2_FEATURE_INCOMPAT_CSUM_V3))
+ tag3->t_checksum = cpu_to_be32(csum32);
+ else
+ tag->t_checksum = cpu_to_be16(csum32);
+}
+/*
+ * jbd2_journal_commit_transaction
+ *
+ * The primary function for committing a transaction to the log. This
+ * function is called by the journal thread to begin a complete commit.
+ */
+void jbd2_journal_commit_transaction(journal_t *journal)
+{
+ struct transaction_stats_s stats;
+ transaction_t *commit_transaction;
+ struct journal_head *jh;
+ struct buffer_head *descriptor;
+ struct buffer_head **wbuf = journal->j_wbuf;
+ int bufs;
+ int flags;
+ int err;
+ unsigned long long blocknr;
+ ktime_t start_time;
+ u64 commit_time;
+ char *tagp = NULL;
+ journal_header_t *header;
+ journal_block_tag_t *tag = NULL;
+ int space_left = 0;
+ int first_tag = 0;
+ int tag_flag;
+ int i;
+ int tag_bytes = journal_tag_bytes(journal);
+ struct buffer_head *cbh = NULL; /* For transactional checksums */
+ __u32 crc32_sum = ~0;
+ struct blk_plug plug;
+ /* Tail of the journal */
+ unsigned long first_block;
+ tid_t first_tid;
+ int update_tail;
+ int csum_size = 0;
+ LIST_HEAD(io_bufs);
+ LIST_HEAD(log_bufs);
+
+ if (jbd2_journal_has_csum_v2or3(journal))
+ csum_size = sizeof(struct jbd2_journal_block_tail);
+
+ /*
+ * First job: lock down the current transaction and wait for
+ * all outstanding updates to complete.
+ */
+
+ /* Do we need to erase the effects of a prior jbd2_journal_flush? */
+ if (journal->j_flags & JBD2_FLUSHED) {
+ jbd_debug(3, "super block updated\n");
+ mutex_lock(&journal->j_checkpoint_mutex);
+ /*
+ * We hold j_checkpoint_mutex so tail cannot change under us.
+ * We don't need any special data guarantees for writing sb
+ * since journal is empty and it is ok for write to be
+ * flushed only with transaction commit.
+ */
+ jbd2_journal_update_sb_log_tail(journal,
+ journal->j_tail_sequence,
+ journal->j_tail,
+ WRITE_SYNC);
+ mutex_unlock(&journal->j_checkpoint_mutex);
+ } else {
+ jbd_debug(3, "superblock not updated\n");
+ }
+
+ J_ASSERT(journal->j_running_transaction != NULL);
+ J_ASSERT(journal->j_committing_transaction == NULL);
+
+ commit_transaction = journal->j_running_transaction;
+
+ trace_jbd2_start_commit(journal, commit_transaction);
+ jbd_debug(1, "JBD2: starting commit of transaction %d\n",
+ commit_transaction->t_tid);
+
+ write_lock(&journal->j_state_lock);
+ J_ASSERT(commit_transaction->t_state == T_RUNNING);
+ commit_transaction->t_state = T_LOCKED;
+
+ trace_jbd2_commit_locking(journal, commit_transaction);
+ stats.run.rs_wait = commit_transaction->t_max_wait;
+ stats.run.rs_request_delay = 0;
+ stats.run.rs_locked = jiffies;
+ if (commit_transaction->t_requested)
+ stats.run.rs_request_delay =
+ jbd2_time_diff(commit_transaction->t_requested,
+ stats.run.rs_locked);
+ stats.run.rs_running = jbd2_time_diff(commit_transaction->t_start,
+ stats.run.rs_locked);
+
+ spin_lock(&commit_transaction->t_handle_lock);
+ while (atomic_read(&commit_transaction->t_updates)) {
+ DEFINE_WAIT(wait);
+
+ prepare_to_wait(&journal->j_wait_updates, &wait,
+ TASK_UNINTERRUPTIBLE);
+ if (atomic_read(&commit_transaction->t_updates)) {
+ spin_unlock(&commit_transaction->t_handle_lock);
+ write_unlock(&journal->j_state_lock);
+ schedule();
+ write_lock(&journal->j_state_lock);
+ spin_lock(&commit_transaction->t_handle_lock);
+ }
+ finish_wait(&journal->j_wait_updates, &wait);
+ }
+ spin_unlock(&commit_transaction->t_handle_lock);
+
+ J_ASSERT (atomic_read(&commit_transaction->t_outstanding_credits) <=
+ journal->j_max_transaction_buffers);
+
+ /*
+ * First thing we are allowed to do is to discard any remaining
+ * BJ_Reserved buffers. Note, it is _not_ permissible to assume
+ * that there are no such buffers: if a large filesystem
+ * operation like a truncate needs to split itself over multiple
+ * transactions, then it may try to do a jbd2_journal_restart() while
+ * there are still BJ_Reserved buffers outstanding. These must
+ * be released cleanly from the current transaction.
+ *
+ * In this case, the filesystem must still reserve write access
+ * again before modifying the buffer in the new transaction, but
+ * we do not require it to remember exactly which old buffers it
+ * has reserved. This is consistent with the existing behaviour
+ * that multiple jbd2_journal_get_write_access() calls to the same
+ * buffer are perfectly permissible.
+ */
+ while (commit_transaction->t_reserved_list) {
+ jh = commit_transaction->t_reserved_list;
+ JBUFFER_TRACE(jh, "reserved, unused: refile");
+ /*
+ * A jbd2_journal_get_undo_access()+jbd2_journal_release_buffer() may
+ * leave undo-committed data.
+ */
+ if (jh->b_committed_data) {
+ struct buffer_head *bh = jh2bh(jh);
+
+ jbd_lock_bh_state(bh);
+ jbd2_free(jh->b_committed_data, bh->b_size);
+ jh->b_committed_data = NULL;
+ jbd_unlock_bh_state(bh);
+ }
+ jbd2_journal_refile_buffer(journal, jh);
+ }
+
+ /*
+ * Now try to drop any written-back buffers from the journal's
+ * checkpoint lists. We do this *before* commit because it potentially
+ * frees some memory
+ */
+ spin_lock(&journal->j_list_lock);
+ __jbd2_journal_clean_checkpoint_list(journal);
+ spin_unlock(&journal->j_list_lock);
+
+ jbd_debug(3, "JBD2: commit phase 1\n");
+
+ /*
+ * Clear revoked flag to reflect there is no revoked buffers
+ * in the next transaction which is going to be started.
+ */
+ jbd2_clear_buffer_revoked_flags(journal);
+
+ /*
+ * Switch to a new revoke table.
+ */
+ jbd2_journal_switch_revoke_table(journal);
+
+ /*
+ * Reserved credits cannot be claimed anymore, free them
+ */
+ atomic_sub(atomic_read(&journal->j_reserved_credits),
+ &commit_transaction->t_outstanding_credits);
+
+ trace_jbd2_commit_flushing(journal, commit_transaction);
+ stats.run.rs_flushing = jiffies;
+ stats.run.rs_locked = jbd2_time_diff(stats.run.rs_locked,
+ stats.run.rs_flushing);
+
+ commit_transaction->t_state = T_FLUSH;
+ journal->j_committing_transaction = commit_transaction;
+ journal->j_running_transaction = NULL;
+ start_time = ktime_get();
+ commit_transaction->t_log_start = journal->j_head;
+ wake_up(&journal->j_wait_transaction_locked);
+ write_unlock(&journal->j_state_lock);
+
+ jbd_debug(3, "JBD2: commit phase 2a\n");
+
+ /*
+ * Now start flushing things to disk, in the order they appear
+ * on the transaction lists. Data blocks go first.
+ */
+ err = journal_submit_data_buffers(journal, commit_transaction);
+ if (err)
+ jbd2_journal_abort(journal, err);
+
+ blk_start_plug(&plug);
+ jbd2_journal_write_revoke_records(journal, commit_transaction,
+ &log_bufs, WRITE_SYNC);
+
+ jbd_debug(3, "JBD2: commit phase 2b\n");
+
+ /*
+ * Way to go: we have now written out all of the data for a
+ * transaction! Now comes the tricky part: we need to write out
+ * metadata. Loop over the transaction's entire buffer list:
+ */
+ write_lock(&journal->j_state_lock);
+ commit_transaction->t_state = T_COMMIT;
+ write_unlock(&journal->j_state_lock);
+
+ trace_jbd2_commit_logging(journal, commit_transaction);
+ stats.run.rs_logging = jiffies;
+ stats.run.rs_flushing = jbd2_time_diff(stats.run.rs_flushing,
+ stats.run.rs_logging);
+ stats.run.rs_blocks =
+ atomic_read(&commit_transaction->t_outstanding_credits);
+ stats.run.rs_blocks_logged = 0;
+
+ J_ASSERT(commit_transaction->t_nr_buffers <=
+ atomic_read(&commit_transaction->t_outstanding_credits));
+
+ err = 0;
+ bufs = 0;
+ descriptor = NULL;
+ while (commit_transaction->t_buffers) {
+
+ /* Find the next buffer to be journaled... */
+
+ jh = commit_transaction->t_buffers;
+
+ /* If we're in abort mode, we just un-journal the buffer and
+ release it. */
+
+ if (is_journal_aborted(journal)) {
+ clear_buffer_jbddirty(jh2bh(jh));
+ JBUFFER_TRACE(jh, "journal is aborting: refile");
+ jbd2_buffer_abort_trigger(jh,
+ jh->b_frozen_data ?
+ jh->b_frozen_triggers :
+ jh->b_triggers);
+ jbd2_journal_refile_buffer(journal, jh);
+ /* If that was the last one, we need to clean up
+ * any descriptor buffers which may have been
+ * already allocated, even if we are now
+ * aborting. */
+ if (!commit_transaction->t_buffers)
+ goto start_journal_io;
+ continue;
+ }
+
+ /* Make sure we have a descriptor block in which to
+ record the metadata buffer. */
+
+ if (!descriptor) {
+ J_ASSERT (bufs == 0);
+
+ jbd_debug(4, "JBD2: get descriptor\n");
+
+ descriptor = jbd2_journal_get_descriptor_buffer(journal);
+ if (!descriptor) {
+ jbd2_journal_abort(journal, -EIO);
+ continue;
+ }
+
+ jbd_debug(4, "JBD2: got buffer %llu (%p)\n",
+ (unsigned long long)descriptor->b_blocknr,
+ descriptor->b_data);
+ header = (journal_header_t *)descriptor->b_data;
+ header->h_magic = cpu_to_be32(JBD2_MAGIC_NUMBER);
+ header->h_blocktype = cpu_to_be32(JBD2_DESCRIPTOR_BLOCK);
+ header->h_sequence = cpu_to_be32(commit_transaction->t_tid);
+
+ tagp = &descriptor->b_data[sizeof(journal_header_t)];
+ space_left = descriptor->b_size -
+ sizeof(journal_header_t);
+ first_tag = 1;
+ set_buffer_jwrite(descriptor);
+ set_buffer_dirty(descriptor);
+ wbuf[bufs++] = descriptor;
+
+ /* Record it so that we can wait for IO
+ completion later */
+ BUFFER_TRACE(descriptor, "ph3: file as descriptor");
+ jbd2_file_log_bh(&log_bufs, descriptor);
+ }
+
+ /* Where is the buffer to be written? */
+
+ err = jbd2_journal_next_log_block(journal, &blocknr);
+ /* If the block mapping failed, just abandon the buffer
+ and repeat this loop: we'll fall into the
+ refile-on-abort condition above. */
+ if (err) {
+ jbd2_journal_abort(journal, err);
+ continue;
+ }
+
+ /*
+ * start_this_handle() uses t_outstanding_credits to determine
+ * the free space in the log, but this counter is changed
+ * by jbd2_journal_next_log_block() also.
+ */
+ atomic_dec(&commit_transaction->t_outstanding_credits);
+
+ /* Bump b_count to prevent truncate from stumbling over
+ the shadowed buffer! @@@ This can go if we ever get
+ rid of the shadow pairing of buffers. */
+ atomic_inc(&jh2bh(jh)->b_count);
+
+ /*
+ * Make a temporary IO buffer with which to write it out
+ * (this will requeue the metadata buffer to BJ_Shadow).
+ */
+ set_bit(BH_JWrite, &jh2bh(jh)->b_state);
+ JBUFFER_TRACE(jh, "ph3: write metadata");
+ flags = jbd2_journal_write_metadata_buffer(commit_transaction,
+ jh, &wbuf[bufs], blocknr);
+ if (flags < 0) {
+ jbd2_journal_abort(journal, flags);
+ continue;
+ }
+ jbd2_file_log_bh(&io_bufs, wbuf[bufs]);
+
+ /* Record the new block's tag in the current descriptor
+ buffer */
+
+ tag_flag = 0;
+ if (flags & 1)
+ tag_flag |= JBD2_FLAG_ESCAPE;
+ if (!first_tag)
+ tag_flag |= JBD2_FLAG_SAME_UUID;
+
+ tag = (journal_block_tag_t *) tagp;
+ write_tag_block(journal, tag, jh2bh(jh)->b_blocknr);
+ tag->t_flags = cpu_to_be16(tag_flag);
+ jbd2_block_tag_csum_set(journal, tag, wbuf[bufs],
+ commit_transaction->t_tid);
+ tagp += tag_bytes;
+ space_left -= tag_bytes;
+ bufs++;
+
+ if (first_tag) {
+ memcpy (tagp, journal->j_uuid, 16);
+ tagp += 16;
+ space_left -= 16;
+ first_tag = 0;
+ }
+
+ /* If there's no more to do, or if the descriptor is full,
+ let the IO rip! */
+
+ if (bufs == journal->j_wbufsize ||
+ commit_transaction->t_buffers == NULL ||
+ space_left < tag_bytes + 16 + csum_size) {
+
+ jbd_debug(4, "JBD2: Submit %d IOs\n", bufs);
+
+ /* Write an end-of-descriptor marker before
+ submitting the IOs. "tag" still points to
+ the last tag we set up. */
+
+ tag->t_flags |= cpu_to_be16(JBD2_FLAG_LAST_TAG);
+
+ jbd2_descr_block_csum_set(journal, descriptor);
+start_journal_io:
+ for (i = 0; i < bufs; i++) {
+ struct buffer_head *bh = wbuf[i];
+ /*
+ * Compute checksum.
+ */
+ if (JBD2_HAS_COMPAT_FEATURE(journal,
+ JBD2_FEATURE_COMPAT_CHECKSUM)) {
+ crc32_sum =
+ jbd2_checksum_data(crc32_sum, bh);
+ }
+
+ lock_buffer(bh);
+ clear_buffer_dirty(bh);
+ set_buffer_uptodate(bh);
+ bh->b_end_io = journal_end_buffer_io_sync;
+ submit_bh(WRITE_SYNC, bh);
+ }
+ cond_resched();
+ stats.run.rs_blocks_logged += bufs;
+
+ /* Force a new descriptor to be generated next
+ time round the loop. */
+ descriptor = NULL;
+ bufs = 0;
+ }
+ }
+
+ err = journal_finish_inode_data_buffers(journal, commit_transaction);
+ if (err) {
+ printk(KERN_WARNING
+ "JBD2: Detected IO errors while flushing file data "
+ "on %s\n", journal->j_devname);
+ if (journal->j_flags & JBD2_ABORT_ON_SYNCDATA_ERR)
+ jbd2_journal_abort(journal, err);
+ err = 0;
+ }
+
+ /*
+ * Get current oldest transaction in the log before we issue flush
+ * to the filesystem device. After the flush we can be sure that
+ * blocks of all older transactions are checkpointed to persistent
+ * storage and we will be safe to update journal start in the
+ * superblock with the numbers we get here.
+ */
+ update_tail =
+ jbd2_journal_get_log_tail(journal, &first_tid, &first_block);
+
+ write_lock(&journal->j_state_lock);
+ if (update_tail) {
+ long freed = first_block - journal->j_tail;
+
+ if (first_block < journal->j_tail)
+ freed += journal->j_last - journal->j_first;
+ /* Update tail only if we free significant amount of space */
+ if (freed < journal->j_maxlen / 4)
+ update_tail = 0;
+ }
+ J_ASSERT(commit_transaction->t_state == T_COMMIT);
+ commit_transaction->t_state = T_COMMIT_DFLUSH;
+ write_unlock(&journal->j_state_lock);
+
+ /*
+ * If the journal is not located on the file system device,
+ * then we must flush the file system device before we issue
+ * the commit record
+ */
+ if (commit_transaction->t_need_data_flush &&
+ (journal->j_fs_dev != journal->j_dev) &&
+ (journal->j_flags & JBD2_BARRIER))
+ blkdev_issue_flush(journal->j_fs_dev, GFP_NOFS, NULL);
+
+ /* Done it all: now write the commit record asynchronously. */
+ if (JBD2_HAS_INCOMPAT_FEATURE(journal,
+ JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT)) {
+ err = journal_submit_commit_record(journal, commit_transaction,
+ &cbh, crc32_sum);
+ if (err)
+ __jbd2_journal_abort_hard(journal);
+ }
+
+ blk_finish_plug(&plug);
+
+ /* Lo and behold: we have just managed to send a transaction to
+ the log. Before we can commit it, wait for the IO so far to
+ complete. Control buffers being written are on the
+ transaction's t_log_list queue, and metadata buffers are on
+ the io_bufs list.
+
+ Wait for the buffers in reverse order. That way we are
+ less likely to be woken up until all IOs have completed, and
+ so we incur less scheduling load.
+ */
+
+ jbd_debug(3, "JBD2: commit phase 3\n");
+
+ while (!list_empty(&io_bufs)) {
+ struct buffer_head *bh = list_entry(io_bufs.prev,
+ struct buffer_head,
+ b_assoc_buffers);
+
+ wait_on_buffer(bh);
+ cond_resched();
+
+ if (unlikely(!buffer_uptodate(bh)))
+ err = -EIO;
+ jbd2_unfile_log_bh(bh);
+
+ /*
+ * The list contains temporary buffer heads created by
+ * jbd2_journal_write_metadata_buffer().
+ */
+ BUFFER_TRACE(bh, "dumping temporary bh");
+ __brelse(bh);
+ J_ASSERT_BH(bh, atomic_read(&bh->b_count) == 0);
+ free_buffer_head(bh);
+
+ /* We also have to refile the corresponding shadowed buffer */
+ jh = commit_transaction->t_shadow_list->b_tprev;
+ bh = jh2bh(jh);
+ clear_buffer_jwrite(bh);
+ J_ASSERT_BH(bh, buffer_jbddirty(bh));
+ J_ASSERT_BH(bh, !buffer_shadow(bh));
+
+ /* The metadata is now released for reuse, but we need
+ to remember it against this transaction so that when
+ we finally commit, we can do any checkpointing
+ required. */
+ JBUFFER_TRACE(jh, "file as BJ_Forget");
+ jbd2_journal_file_buffer(jh, commit_transaction, BJ_Forget);
+ JBUFFER_TRACE(jh, "brelse shadowed buffer");
+ __brelse(bh);
+ }
+
+ J_ASSERT (commit_transaction->t_shadow_list == NULL);
+
+ jbd_debug(3, "JBD2: commit phase 4\n");
+
+ /* Here we wait for the revoke record and descriptor record buffers */
+ while (!list_empty(&log_bufs)) {
+ struct buffer_head *bh;
+
+ bh = list_entry(log_bufs.prev, struct buffer_head, b_assoc_buffers);
+ wait_on_buffer(bh);
+ cond_resched();
+
+ if (unlikely(!buffer_uptodate(bh)))
+ err = -EIO;
+
+ BUFFER_TRACE(bh, "ph5: control buffer writeout done: unfile");
+ clear_buffer_jwrite(bh);
+ jbd2_unfile_log_bh(bh);
+ __brelse(bh); /* One for getblk */
+ /* AKPM: bforget here */
+ }
+
+ if (err)
+ jbd2_journal_abort(journal, err);
+
+ jbd_debug(3, "JBD2: commit phase 5\n");
+ write_lock(&journal->j_state_lock);
+ J_ASSERT(commit_transaction->t_state == T_COMMIT_DFLUSH);
+ commit_transaction->t_state = T_COMMIT_JFLUSH;
+ write_unlock(&journal->j_state_lock);
+
+ if (!JBD2_HAS_INCOMPAT_FEATURE(journal,
+ JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT)) {
+ err = journal_submit_commit_record(journal, commit_transaction,
+ &cbh, crc32_sum);
+ if (err)
+ __jbd2_journal_abort_hard(journal);
+ }
+ if (cbh)
+ err = journal_wait_on_commit_record(journal, cbh);
+ if (JBD2_HAS_INCOMPAT_FEATURE(journal,
+ JBD2_FEATURE_INCOMPAT_ASYNC_COMMIT) &&
+ journal->j_flags & JBD2_BARRIER) {
+ blkdev_issue_flush(journal->j_dev, GFP_NOFS, NULL);
+ }
+
+ if (err)
+ jbd2_journal_abort(journal, err);
+
+ /*
+ * Now disk caches for filesystem device are flushed so we are safe to
+ * erase checkpointed transactions from the log by updating journal
+ * superblock.
+ */
+ if (update_tail)
+ jbd2_update_log_tail(journal, first_tid, first_block);
+
+ /* End of a transaction! Finally, we can do checkpoint
+ processing: any buffers committed as a result of this
+ transaction can be removed from any checkpoint list it was on
+ before. */
+
+ jbd_debug(3, "JBD2: commit phase 6\n");
+
+ J_ASSERT(list_empty(&commit_transaction->t_inode_list));
+ J_ASSERT(commit_transaction->t_buffers == NULL);
+ J_ASSERT(commit_transaction->t_checkpoint_list == NULL);
+ J_ASSERT(commit_transaction->t_shadow_list == NULL);
+
+restart_loop:
+ /*
+ * As there are other places (journal_unmap_buffer()) adding buffers
+ * to this list we have to be careful and hold the j_list_lock.
+ */
+ spin_lock(&journal->j_list_lock);
+ while (commit_transaction->t_forget) {
+ transaction_t *cp_transaction;
+ struct buffer_head *bh;
+ int try_to_free = 0;
+
+ jh = commit_transaction->t_forget;
+ spin_unlock(&journal->j_list_lock);
+ bh = jh2bh(jh);
+ /*
+ * Get a reference so that bh cannot be freed before we are
+ * done with it.
+ */
+ get_bh(bh);
+ jbd_lock_bh_state(bh);
+ J_ASSERT_JH(jh, jh->b_transaction == commit_transaction);
+
+ /*
+ * If there is undo-protected committed data against
+ * this buffer, then we can remove it now. If it is a
+ * buffer needing such protection, the old frozen_data
+ * field now points to a committed version of the
+ * buffer, so rotate that field to the new committed
+ * data.
+ *
+ * Otherwise, we can just throw away the frozen data now.
+ *
+ * We also know that the frozen data has already fired
+ * its triggers if they exist, so we can clear that too.
+ */
+ if (jh->b_committed_data) {
+ jbd2_free(jh->b_committed_data, bh->b_size);
+ jh->b_committed_data = NULL;
+ if (jh->b_frozen_data) {
+ jh->b_committed_data = jh->b_frozen_data;
+ jh->b_frozen_data = NULL;
+ jh->b_frozen_triggers = NULL;
+ }
+ } else if (jh->b_frozen_data) {
+ jbd2_free(jh->b_frozen_data, bh->b_size);
+ jh->b_frozen_data = NULL;
+ jh->b_frozen_triggers = NULL;
+ }
+
+ spin_lock(&journal->j_list_lock);
+ cp_transaction = jh->b_cp_transaction;
+ if (cp_transaction) {
+ JBUFFER_TRACE(jh, "remove from old cp transaction");
+ cp_transaction->t_chp_stats.cs_dropped++;
+ __jbd2_journal_remove_checkpoint(jh);
+ }
+
+ /* Only re-checkpoint the buffer_head if it is marked
+ * dirty. If the buffer was added to the BJ_Forget list
+ * by jbd2_journal_forget, it may no longer be dirty and
+ * there's no point in keeping a checkpoint record for
+ * it. */
+
+ /*
+ * A buffer which has been freed while still being journaled by
+ * a previous transaction.
+ */
+ if (buffer_freed(bh)) {
+ /*
+ * If the running transaction is the one containing
+ * "add to orphan" operation (b_next_transaction !=
+ * NULL), we have to wait for that transaction to
+ * commit before we can really get rid of the buffer.
+ * So just clear b_modified to not confuse transaction
+ * credit accounting and refile the buffer to
+ * BJ_Forget of the running transaction. If the just
+ * committed transaction contains "add to orphan"
+ * operation, we can completely invalidate the buffer
+ * now. We are rather through in that since the
+ * buffer may be still accessible when blocksize <
+ * pagesize and it is attached to the last partial
+ * page.
+ */
+ jh->b_modified = 0;
+ if (!jh->b_next_transaction) {
+ clear_buffer_freed(bh);
+ clear_buffer_jbddirty(bh);
+ clear_buffer_mapped(bh);
+ clear_buffer_new(bh);
+ clear_buffer_req(bh);
+ bh->b_bdev = NULL;
+ }
+ }
+
+ if (buffer_jbddirty(bh)) {
+ JBUFFER_TRACE(jh, "add to new checkpointing trans");
+ __jbd2_journal_insert_checkpoint(jh, commit_transaction);
+ if (is_journal_aborted(journal))
+ clear_buffer_jbddirty(bh);
+ } else {
+ J_ASSERT_BH(bh, !buffer_dirty(bh));
+ /*
+ * The buffer on BJ_Forget list and not jbddirty means
+ * it has been freed by this transaction and hence it
+ * could not have been reallocated until this
+ * transaction has committed. *BUT* it could be
+ * reallocated once we have written all the data to
+ * disk and before we process the buffer on BJ_Forget
+ * list.
+ */
+ if (!jh->b_next_transaction)
+ try_to_free = 1;
+ }
+ JBUFFER_TRACE(jh, "refile or unfile buffer");
+ __jbd2_journal_refile_buffer(jh);
+ jbd_unlock_bh_state(bh);
+ if (try_to_free)
+ release_buffer_page(bh); /* Drops bh reference */
+ else
+ __brelse(bh);
+ cond_resched_lock(&journal->j_list_lock);
+ }
+ spin_unlock(&journal->j_list_lock);
+ /*
+ * This is a bit sleazy. We use j_list_lock to protect transition
+ * of a transaction into T_FINISHED state and calling
+ * __jbd2_journal_drop_transaction(). Otherwise we could race with
+ * other checkpointing code processing the transaction...
+ */
+ write_lock(&journal->j_state_lock);
+ spin_lock(&journal->j_list_lock);
+ /*
+ * Now recheck if some buffers did not get attached to the transaction
+ * while the lock was dropped...
+ */
+ if (commit_transaction->t_forget) {
+ spin_unlock(&journal->j_list_lock);
+ write_unlock(&journal->j_state_lock);
+ goto restart_loop;
+ }
+
+ /* Add the transaction to the checkpoint list
+ * __journal_remove_checkpoint() can not destroy transaction
+ * under us because it is not marked as T_FINISHED yet */
+ if (journal->j_checkpoint_transactions == NULL) {
+ journal->j_checkpoint_transactions = commit_transaction;
+ commit_transaction->t_cpnext = commit_transaction;
+ commit_transaction->t_cpprev = commit_transaction;
+ } else {
+ commit_transaction->t_cpnext =
+ journal->j_checkpoint_transactions;
+ commit_transaction->t_cpprev =
+ commit_transaction->t_cpnext->t_cpprev;
+ commit_transaction->t_cpnext->t_cpprev =
+ commit_transaction;
+ commit_transaction->t_cpprev->t_cpnext =
+ commit_transaction;
+ }
+ spin_unlock(&journal->j_list_lock);
+
+ /* Done with this transaction! */
+
+ jbd_debug(3, "JBD2: commit phase 7\n");
+
+ J_ASSERT(commit_transaction->t_state == T_COMMIT_JFLUSH);
+
+ commit_transaction->t_start = jiffies;
+ stats.run.rs_logging = jbd2_time_diff(stats.run.rs_logging,
+ commit_transaction->t_start);
+
+ /*
+ * File the transaction statistics
+ */
+ stats.ts_tid = commit_transaction->t_tid;
+ stats.run.rs_handle_count =
+ atomic_read(&commit_transaction->t_handle_count);
+ trace_jbd2_run_stats(journal->j_fs_dev->bd_dev,
+ commit_transaction->t_tid, &stats.run);
+ stats.ts_requested = (commit_transaction->t_requested) ? 1 : 0;
+
+ commit_transaction->t_state = T_COMMIT_CALLBACK;
+ J_ASSERT(commit_transaction == journal->j_committing_transaction);
+ journal->j_commit_sequence = commit_transaction->t_tid;
+ journal->j_committing_transaction = NULL;
+ commit_time = ktime_to_ns(ktime_sub(ktime_get(), start_time));
+
+ /*
+ * weight the commit time higher than the average time so we don't
+ * react too strongly to vast changes in the commit time
+ */
+ if (likely(journal->j_average_commit_time))
+ journal->j_average_commit_time = (commit_time +
+ journal->j_average_commit_time*3) / 4;
+ else
+ journal->j_average_commit_time = commit_time;
+
+ write_unlock(&journal->j_state_lock);
+
+ if (journal->j_commit_callback)
+ journal->j_commit_callback(journal, commit_transaction);
+
+ trace_jbd2_end_commit(journal, commit_transaction);
+ jbd_debug(1, "JBD2: commit %d complete, head %d\n",
+ journal->j_commit_sequence, journal->j_tail_sequence);
+
+ write_lock(&journal->j_state_lock);
+ spin_lock(&journal->j_list_lock);
+ commit_transaction->t_state = T_FINISHED;
+ /* Check if the transaction can be dropped now that we are finished */
+ if (commit_transaction->t_checkpoint_list == NULL &&
+ commit_transaction->t_checkpoint_io_list == NULL) {
+ __jbd2_journal_drop_transaction(journal, commit_transaction);
+ jbd2_journal_free_transaction(commit_transaction);
+ }
+ spin_unlock(&journal->j_list_lock);
+ write_unlock(&journal->j_state_lock);
+ wake_up(&journal->j_wait_done_commit);
+
+ /*
+ * Calculate overall stats
+ */
+ spin_lock(&journal->j_history_lock);
+ journal->j_stats.ts_tid++;
+ journal->j_stats.ts_requested += stats.ts_requested;
+ journal->j_stats.run.rs_wait += stats.run.rs_wait;
+ journal->j_stats.run.rs_request_delay += stats.run.rs_request_delay;
+ journal->j_stats.run.rs_running += stats.run.rs_running;
+ journal->j_stats.run.rs_locked += stats.run.rs_locked;
+ journal->j_stats.run.rs_flushing += stats.run.rs_flushing;
+ journal->j_stats.run.rs_logging += stats.run.rs_logging;
+ journal->j_stats.run.rs_handle_count += stats.run.rs_handle_count;
+ journal->j_stats.run.rs_blocks += stats.run.rs_blocks;
+ journal->j_stats.run.rs_blocks_logged += stats.run.rs_blocks_logged;
+ spin_unlock(&journal->j_history_lock);
+}
Code Review / kvmfornfv.git / blobdiff