+++ /dev/null
-/*
- * linux/fs/jbd/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/jbd.h>
-#include <linux/errno.h>
-#include <linux/mm.h>
-#include <linux/pagemap.h>
-#include <linux/bio.h>
-#include <linux/blkdev.h>
-#include <trace/events/jbd.h>
-
-/*
- * Default IO end handler for temporary BJ_IO buffer_heads.
- */
-static void journal_end_buffer_io_sync(struct buffer_head *bh, int uptodate)
-{
- BUFFER_TRACE(bh, "");
- if (uptodate)
- set_buffer_uptodate(bh);
- else
- clear_buffer_uptodate(bh);
- unlock_buffer(bh);
-}
-
-/*
- * When an ext3-ordered file is truncated, it is possible that many 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 journal->j_list_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);
-}
-
-/*
- * Decrement reference counter for data buffer. If it has been marked
- * 'BH_Freed', release it and the page to which it belongs if possible.
- */
-static void release_data_buffer(struct buffer_head *bh)
-{
- if (buffer_freed(bh)) {
- WARN_ON_ONCE(buffer_dirty(bh));
- clear_buffer_freed(bh);
- clear_buffer_mapped(bh);
- clear_buffer_new(bh);
- clear_buffer_req(bh);
- bh->b_bdev = NULL;
- release_buffer_page(bh);
- } else
- put_bh(bh);
-}
-
-/*
- * Try to acquire jbd_lock_bh_state() against the buffer, when j_list_lock is
- * held. For ranking reasons we must trylock. If we lose, schedule away and
- * return 0. j_list_lock is dropped in this case.
- */
-static int inverted_lock(journal_t *journal, struct buffer_head *bh)
-{
- if (!jbd_trylock_bh_state(bh)) {
- spin_unlock(&journal->j_list_lock);
- schedule();
- return 0;
- }
- return 1;
-}
-
-/* Done it all: now write 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_write_commit_record(journal_t *journal,
- transaction_t *commit_transaction)
-{
- struct journal_head *descriptor;
- struct buffer_head *bh;
- journal_header_t *header;
- int ret;
-
- if (is_journal_aborted(journal))
- return 0;
-
- descriptor = journal_get_descriptor_buffer(journal);
- if (!descriptor)
- return 1;
-
- bh = jh2bh(descriptor);
-
- header = (journal_header_t *)(bh->b_data);
- header->h_magic = cpu_to_be32(JFS_MAGIC_NUMBER);
- header->h_blocktype = cpu_to_be32(JFS_COMMIT_BLOCK);
- header->h_sequence = cpu_to_be32(commit_transaction->t_tid);
-
- JBUFFER_TRACE(descriptor, "write commit block");
- set_buffer_dirty(bh);
-
- if (journal->j_flags & JFS_BARRIER)
- ret = __sync_dirty_buffer(bh, WRITE_SYNC | WRITE_FLUSH_FUA);
- else
- ret = sync_dirty_buffer(bh);
-
- put_bh(bh); /* One for getblk() */
- journal_put_journal_head(descriptor);
-
- return (ret == -EIO);
-}
-
-static void journal_do_submit_data(struct buffer_head **wbuf, int bufs,
- int write_op)
-{
- int i;
-
- for (i = 0; i < bufs; i++) {
- wbuf[i]->b_end_io = end_buffer_write_sync;
- /*
- * Here we write back pagecache data that may be mmaped. Since
- * we cannot afford to clean the page and set PageWriteback
- * here due to lock ordering (page lock ranks above transaction
- * start), the data can change while IO is in flight. Tell the
- * block layer it should bounce the bio pages if stable data
- * during write is required.
- *
- * We use up our safety reference in submit_bh().
- */
- _submit_bh(write_op, wbuf[i], 1 << BIO_SNAP_STABLE);
- }
-}
-
-/*
- * Submit all the data buffers to disk
- */
-static int journal_submit_data_buffers(journal_t *journal,
- transaction_t *commit_transaction,
- int write_op)
-{
- struct journal_head *jh;
- struct buffer_head *bh;
- int locked;
- int bufs = 0;
- struct buffer_head **wbuf = journal->j_wbuf;
- int err = 0;
-
- /*
- * Whenever we unlock the journal and sleep, things can get added
- * onto ->t_sync_datalist, so we have to keep looping back to
- * write_out_data until we *know* that the list is empty.
- *
- * Cleanup any flushed data buffers from the data list. Even in
- * abort mode, we want to flush this out as soon as possible.
- */
-write_out_data:
- cond_resched();
- spin_lock(&journal->j_list_lock);
-
- while (commit_transaction->t_sync_datalist) {
- jh = commit_transaction->t_sync_datalist;
- bh = jh2bh(jh);
- locked = 0;
-
- /* Get reference just to make sure buffer does not disappear
- * when we are forced to drop various locks */
- get_bh(bh);
- /* If the buffer is dirty, we need to submit IO and hence
- * we need the buffer lock. We try to lock the buffer without
- * blocking. If we fail, we need to drop j_list_lock and do
- * blocking lock_buffer().
- */
- if (buffer_dirty(bh)) {
- if (!trylock_buffer(bh)) {
- BUFFER_TRACE(bh, "needs blocking lock");
- spin_unlock(&journal->j_list_lock);
- trace_jbd_do_submit_data(journal,
- commit_transaction);
- /* Write out all data to prevent deadlocks */
- journal_do_submit_data(wbuf, bufs, write_op);
- bufs = 0;
- lock_buffer(bh);
- spin_lock(&journal->j_list_lock);
- }
- locked = 1;
- }
- /* We have to get bh_state lock. Again out of order, sigh. */
- if (!inverted_lock(journal, bh)) {
- jbd_lock_bh_state(bh);
- spin_lock(&journal->j_list_lock);
- }
- /* Someone already cleaned up the buffer? */
- if (!buffer_jbd(bh) || bh2jh(bh) != jh
- || jh->b_transaction != commit_transaction
- || jh->b_jlist != BJ_SyncData) {
- jbd_unlock_bh_state(bh);
- if (locked)
- unlock_buffer(bh);
- BUFFER_TRACE(bh, "already cleaned up");
- release_data_buffer(bh);
- continue;
- }
- if (locked && test_clear_buffer_dirty(bh)) {
- BUFFER_TRACE(bh, "needs writeout, adding to array");
- wbuf[bufs++] = bh;
- __journal_file_buffer(jh, commit_transaction,
- BJ_Locked);
- jbd_unlock_bh_state(bh);
- if (bufs == journal->j_wbufsize) {
- spin_unlock(&journal->j_list_lock);
- trace_jbd_do_submit_data(journal,
- commit_transaction);
- journal_do_submit_data(wbuf, bufs, write_op);
- bufs = 0;
- goto write_out_data;
- }
- } else if (!locked && buffer_locked(bh)) {
- __journal_file_buffer(jh, commit_transaction,
- BJ_Locked);
- jbd_unlock_bh_state(bh);
- put_bh(bh);
- } else {
- BUFFER_TRACE(bh, "writeout complete: unfile");
- if (unlikely(!buffer_uptodate(bh)))
- err = -EIO;
- __journal_unfile_buffer(jh);
- jbd_unlock_bh_state(bh);
- if (locked)
- unlock_buffer(bh);
- release_data_buffer(bh);
- }
-
- if (need_resched() || spin_needbreak(&journal->j_list_lock)) {
- spin_unlock(&journal->j_list_lock);
- goto write_out_data;
- }
- }
- spin_unlock(&journal->j_list_lock);
- trace_jbd_do_submit_data(journal, commit_transaction);
- journal_do_submit_data(wbuf, bufs, write_op);
-
- return err;
-}
-
-/*
- * 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 journal_commit_transaction(journal_t *journal)
-{
- transaction_t *commit_transaction;
- struct journal_head *jh, *new_jh, *descriptor;
- struct buffer_head **wbuf = journal->j_wbuf;
- int bufs;
- int flags;
- int err;
- unsigned int 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;
- struct blk_plug plug;
- int write_op = WRITE;
-
- /*
- * 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 journal_flush? */
- if (journal->j_flags & JFS_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.
- */
- 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_jbd_start_commit(journal, commit_transaction);
- jbd_debug(1, "JBD: starting commit of transaction %d\n",
- commit_transaction->t_tid);
-
- spin_lock(&journal->j_state_lock);
- J_ASSERT(commit_transaction->t_state == T_RUNNING);
- commit_transaction->t_state = T_LOCKED;
-
- trace_jbd_commit_locking(journal, commit_transaction);
- spin_lock(&commit_transaction->t_handle_lock);
- while (commit_transaction->t_updates) {
- DEFINE_WAIT(wait);
-
- prepare_to_wait(&journal->j_wait_updates, &wait,
- TASK_UNINTERRUPTIBLE);
- if (commit_transaction->t_updates) {
- spin_unlock(&commit_transaction->t_handle_lock);
- spin_unlock(&journal->j_state_lock);
- schedule();
- spin_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 (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 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 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 journal_get_undo_access()+journal_release_buffer() may
- * leave undo-committed data.
- */
- if (jh->b_committed_data) {
- struct buffer_head *bh = jh2bh(jh);
-
- jbd_lock_bh_state(bh);
- jbd_free(jh->b_committed_data, bh->b_size);
- jh->b_committed_data = NULL;
- jbd_unlock_bh_state(bh);
- }
- 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);
- __journal_clean_checkpoint_list(journal);
- spin_unlock(&journal->j_list_lock);
-
- jbd_debug (3, "JBD: commit phase 1\n");
-
- /*
- * Clear revoked flag to reflect there is no revoked buffers
- * in the next transaction which is going to be started.
- */
- journal_clear_buffer_revoked_flags(journal);
-
- /*
- * Switch to a new revoke table.
- */
- journal_switch_revoke_table(journal);
-
- trace_jbd_commit_flushing(journal, commit_transaction);
- 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);
- spin_unlock(&journal->j_state_lock);
-
- jbd_debug (3, "JBD: commit phase 2\n");
-
- if (tid_geq(journal->j_commit_waited, commit_transaction->t_tid))
- write_op = WRITE_SYNC;
-
- /*
- * Now start flushing things to disk, in the order they appear
- * on the transaction lists. Data blocks go first.
- */
- blk_start_plug(&plug);
- err = journal_submit_data_buffers(journal, commit_transaction,
- write_op);
- blk_finish_plug(&plug);
-
- /*
- * Wait for all previously submitted IO to complete.
- */
- spin_lock(&journal->j_list_lock);
- while (commit_transaction->t_locked_list) {
- struct buffer_head *bh;
-
- jh = commit_transaction->t_locked_list->b_tprev;
- bh = jh2bh(jh);
- get_bh(bh);
- if (buffer_locked(bh)) {
- spin_unlock(&journal->j_list_lock);
- wait_on_buffer(bh);
- spin_lock(&journal->j_list_lock);
- }
- if (unlikely(!buffer_uptodate(bh))) {
- if (!trylock_page(bh->b_page)) {
- spin_unlock(&journal->j_list_lock);
- lock_page(bh->b_page);
- spin_lock(&journal->j_list_lock);
- }
- if (bh->b_page->mapping)
- set_bit(AS_EIO, &bh->b_page->mapping->flags);
-
- unlock_page(bh->b_page);
- SetPageError(bh->b_page);
- err = -EIO;
- }
- if (!inverted_lock(journal, bh)) {
- put_bh(bh);
- spin_lock(&journal->j_list_lock);
- continue;
- }
- if (buffer_jbd(bh) && bh2jh(bh) == jh &&
- jh->b_transaction == commit_transaction &&
- jh->b_jlist == BJ_Locked)
- __journal_unfile_buffer(jh);
- jbd_unlock_bh_state(bh);
- release_data_buffer(bh);
- cond_resched_lock(&journal->j_list_lock);
- }
- spin_unlock(&journal->j_list_lock);
-
- if (err) {
- char b[BDEVNAME_SIZE];
-
- printk(KERN_WARNING
- "JBD: Detected IO errors while flushing file data "
- "on %s\n", bdevname(journal->j_fs_dev, b));
- if (journal->j_flags & JFS_ABORT_ON_SYNCDATA_ERR)
- journal_abort(journal, err);
- err = 0;
- }
-
- blk_start_plug(&plug);
-
- journal_write_revoke_records(journal, commit_transaction, write_op);
-
- /*
- * If we found any dirty or locked buffers, then we should have
- * looped back up to the write_out_data label. If there weren't
- * any then journal_clean_data_list should have wiped the list
- * clean by now, so check that it is in fact empty.
- */
- J_ASSERT (commit_transaction->t_sync_datalist == NULL);
-
- jbd_debug (3, "JBD: commit phase 3\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:
- */
- spin_lock(&journal->j_state_lock);
- commit_transaction->t_state = T_COMMIT;
- spin_unlock(&journal->j_state_lock);
-
- trace_jbd_commit_logging(journal, commit_transaction);
- J_ASSERT(commit_transaction->t_nr_buffers <=
- commit_transaction->t_outstanding_credits);
-
- descriptor = NULL;
- bufs = 0;
- 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");
- 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) {
- struct buffer_head *bh;
-
- J_ASSERT (bufs == 0);
-
- jbd_debug(4, "JBD: get descriptor\n");
-
- descriptor = journal_get_descriptor_buffer(journal);
- if (!descriptor) {
- journal_abort(journal, -EIO);
- continue;
- }
-
- bh = jh2bh(descriptor);
- jbd_debug(4, "JBD: got buffer %llu (%p)\n",
- (unsigned long long)bh->b_blocknr, bh->b_data);
- header = (journal_header_t *)&bh->b_data[0];
- header->h_magic = cpu_to_be32(JFS_MAGIC_NUMBER);
- header->h_blocktype = cpu_to_be32(JFS_DESCRIPTOR_BLOCK);
- header->h_sequence = cpu_to_be32(commit_transaction->t_tid);
-
- tagp = &bh->b_data[sizeof(journal_header_t)];
- space_left = bh->b_size - sizeof(journal_header_t);
- first_tag = 1;
- set_buffer_jwrite(bh);
- set_buffer_dirty(bh);
- wbuf[bufs++] = bh;
-
- /* Record it so that we can wait for IO
- completion later */
- BUFFER_TRACE(bh, "ph3: file as descriptor");
- journal_file_buffer(descriptor, commit_transaction,
- BJ_LogCtl);
- }
-
- /* Where is the buffer to be written? */
-
- err = 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) {
- 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 journal_next_log_block() also.
- */
- 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 BJ_IO/BJ_Shadow pairing of buffers. */
- get_bh(jh2bh(jh));
-
- /* Make a temporary IO buffer with which to write it out
- (this will requeue both the metadata buffer and the
- temporary IO buffer). new_bh goes on BJ_IO*/
-
- set_buffer_jwrite(jh2bh(jh));
- /*
- * akpm: journal_write_metadata_buffer() sets
- * new_bh->b_transaction to commit_transaction.
- * We need to clean this up before we release new_bh
- * (which is of type BJ_IO)
- */
- JBUFFER_TRACE(jh, "ph3: write metadata");
- flags = journal_write_metadata_buffer(commit_transaction,
- jh, &new_jh, blocknr);
- set_buffer_jwrite(jh2bh(new_jh));
- wbuf[bufs++] = jh2bh(new_jh);
-
- /* Record the new block's tag in the current descriptor
- buffer */
-
- tag_flag = 0;
- if (flags & 1)
- tag_flag |= JFS_FLAG_ESCAPE;
- if (!first_tag)
- tag_flag |= JFS_FLAG_SAME_UUID;
-
- tag = (journal_block_tag_t *) tagp;
- tag->t_blocknr = cpu_to_be32(jh2bh(jh)->b_blocknr);
- tag->t_flags = cpu_to_be32(tag_flag);
- tagp += sizeof(journal_block_tag_t);
- space_left -= sizeof(journal_block_tag_t);
-
- 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 < sizeof(journal_block_tag_t) + 16) {
-
- jbd_debug(4, "JBD: 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_be32(JFS_FLAG_LAST_TAG);
-
-start_journal_io:
- for (i = 0; i < bufs; i++) {
- struct buffer_head *bh = wbuf[i];
- lock_buffer(bh);
- clear_buffer_dirty(bh);
- set_buffer_uptodate(bh);
- bh->b_end_io = journal_end_buffer_io_sync;
- /*
- * In data=journal mode, here we can end up
- * writing pagecache data that might be
- * mmapped. Since we can't afford to clean the
- * page and set PageWriteback (see the comment
- * near the other use of _submit_bh()), the
- * data can change while the write is in
- * flight. Tell the block layer to bounce the
- * bio pages if stable pages are required.
- */
- _submit_bh(write_op, bh, 1 << BIO_SNAP_STABLE);
- }
- cond_resched();
-
- /* Force a new descriptor to be generated next
- time round the loop. */
- descriptor = NULL;
- bufs = 0;
- }
- }
-
- 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 t_iobuf_list queue.
-
- 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, "JBD: commit phase 4\n");
-
- /*
- * akpm: these are BJ_IO, and j_list_lock is not needed.
- * See __journal_try_to_free_buffer.
- */
-wait_for_iobuf:
- while (commit_transaction->t_iobuf_list != NULL) {
- struct buffer_head *bh;
-
- jh = commit_transaction->t_iobuf_list->b_tprev;
- bh = jh2bh(jh);
- if (buffer_locked(bh)) {
- wait_on_buffer(bh);
- goto wait_for_iobuf;
- }
- if (cond_resched())
- goto wait_for_iobuf;
-
- if (unlikely(!buffer_uptodate(bh)))
- err = -EIO;
-
- clear_buffer_jwrite(bh);
-
- JBUFFER_TRACE(jh, "ph4: unfile after journal write");
- journal_unfile_buffer(journal, jh);
-
- /*
- * ->t_iobuf_list should contain only dummy buffer_heads
- * which were created by journal_write_metadata_buffer().
- */
- BUFFER_TRACE(bh, "dumping temporary bh");
- journal_put_journal_head(jh);
- __brelse(bh);
- J_ASSERT_BH(bh, atomic_read(&bh->b_count) == 0);
- free_buffer_head(bh);
-
- /* We also have to unlock and free 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));
-
- /* 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");
- journal_file_buffer(jh, commit_transaction, BJ_Forget);
- /*
- * Wake up any transactions which were waiting for this
- * IO to complete. The barrier must be here so that changes
- * by journal_file_buffer() take effect before wake_up_bit()
- * does the waitqueue check.
- */
- smp_mb();
- wake_up_bit(&bh->b_state, BH_Unshadow);
- JBUFFER_TRACE(jh, "brelse shadowed buffer");
- __brelse(bh);
- }
-
- J_ASSERT (commit_transaction->t_shadow_list == NULL);
-
- jbd_debug(3, "JBD: commit phase 5\n");
-
- /* Here we wait for the revoke record and descriptor record buffers */
- wait_for_ctlbuf:
- while (commit_transaction->t_log_list != NULL) {
- struct buffer_head *bh;
-
- jh = commit_transaction->t_log_list->b_tprev;
- bh = jh2bh(jh);
- if (buffer_locked(bh)) {
- wait_on_buffer(bh);
- goto wait_for_ctlbuf;
- }
- if (cond_resched())
- goto wait_for_ctlbuf;
-
- if (unlikely(!buffer_uptodate(bh)))
- err = -EIO;
-
- BUFFER_TRACE(bh, "ph5: control buffer writeout done: unfile");
- clear_buffer_jwrite(bh);
- journal_unfile_buffer(journal, jh);
- journal_put_journal_head(jh);
- __brelse(bh); /* One for getblk */
- /* AKPM: bforget here */
- }
-
- if (err)
- journal_abort(journal, err);
-
- jbd_debug(3, "JBD: commit phase 6\n");
-
- /* All metadata is written, now write commit record and do cleanup */
- spin_lock(&journal->j_state_lock);
- J_ASSERT(commit_transaction->t_state == T_COMMIT);
- commit_transaction->t_state = T_COMMIT_RECORD;
- spin_unlock(&journal->j_state_lock);
-
- if (journal_write_commit_record(journal, commit_transaction))
- err = -EIO;
-
- if (err)
- journal_abort(journal, err);
-
- /* 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, "JBD: commit phase 7\n");
-
- J_ASSERT(commit_transaction->t_sync_datalist == NULL);
- J_ASSERT(commit_transaction->t_buffers == NULL);
- J_ASSERT(commit_transaction->t_checkpoint_list == NULL);
- J_ASSERT(commit_transaction->t_iobuf_list == NULL);
- J_ASSERT(commit_transaction->t_shadow_list == NULL);
- J_ASSERT(commit_transaction->t_log_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 ||
- jh->b_transaction == journal->j_running_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.
- */
- if (jh->b_committed_data) {
- jbd_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;
- }
- } else if (jh->b_frozen_data) {
- jbd_free(jh->b_frozen_data, bh->b_size);
- jh->b_frozen_data = NULL;
- }
-
- spin_lock(&journal->j_list_lock);
- cp_transaction = jh->b_cp_transaction;
- if (cp_transaction) {
- JBUFFER_TRACE(jh, "remove from old cp transaction");
- __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 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 throughout 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");
- __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 freed buffer");
- __journal_refile_buffer(jh);
- jbd_unlock_bh_state(bh);
- if (try_to_free)
- release_buffer_page(bh);
- 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
- * __journal_drop_transaction(). Otherwise we could race with
- * other checkpointing code processing the transaction...
- */
- spin_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);
- spin_unlock(&journal->j_state_lock);
- goto restart_loop;
- }
-
- /* Done with this transaction! */
-
- jbd_debug(3, "JBD: commit phase 8\n");
-
- J_ASSERT(commit_transaction->t_state == T_COMMIT_RECORD);
-
- commit_transaction->t_state = T_FINISHED;
- 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 commit time
- */
- if (likely(journal->j_average_commit_time))
- journal->j_average_commit_time = (commit_time*3 +
- journal->j_average_commit_time) / 4;
- else
- journal->j_average_commit_time = commit_time;
-
- spin_unlock(&journal->j_state_lock);
-
- if (commit_transaction->t_checkpoint_list == NULL &&
- commit_transaction->t_checkpoint_io_list == NULL) {
- __journal_drop_transaction(journal, commit_transaction);
- } else {
- 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);
-
- trace_jbd_end_commit(journal, commit_transaction);
- jbd_debug(1, "JBD: commit %d complete, head %d\n",
- journal->j_commit_sequence, journal->j_tail_sequence);
-
- wake_up(&journal->j_wait_done_commit);
-}
Code Review / kvmfornfv.git / blobdiff