| /* |
| * 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/smp_lock.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 sucessfully 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 (TestSetPageLocked(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); |
| } |
| |
| /* |
| * 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; |
| int i, ret; |
| int barrier_done = 0; |
| |
| if (is_journal_aborted(journal)) |
| return 0; |
| |
| descriptor = jbd2_journal_get_descriptor_buffer(journal); |
| if (!descriptor) |
| return 1; |
| |
| bh = jh2bh(descriptor); |
| |
| /* AKPM: buglet - add `i' to tmp! */ |
| for (i = 0; i < bh->b_size; i += 512) { |
| journal_header_t *tmp = (journal_header_t*)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); |
| } |
| |
| JBUFFER_TRACE(descriptor, "write commit block"); |
| set_buffer_dirty(bh); |
| if (journal->j_flags & JBD2_BARRIER) { |
| set_buffer_ordered(bh); |
| barrier_done = 1; |
| } |
| ret = sync_dirty_buffer(bh); |
| /* is it possible for another commit to fail at roughly |
| * the same time as this one? If so, we don't want to |
| * trust the barrier flag in the super, but instead want |
| * to remember if we sent a barrier request |
| */ |
| if (ret == -EOPNOTSUPP && barrier_done) { |
| char b[BDEVNAME_SIZE]; |
| |
| printk(KERN_WARNING |
| "JBD: barrier-based sync failed on %s - " |
| "disabling barriers\n", |
| bdevname(journal->j_dev, b)); |
| spin_lock(&journal->j_state_lock); |
| journal->j_flags &= ~JBD2_BARRIER; |
| spin_unlock(&journal->j_state_lock); |
| |
| /* And try again, without the barrier */ |
| clear_buffer_ordered(bh); |
| set_buffer_uptodate(bh); |
| set_buffer_dirty(bh); |
| ret = sync_dirty_buffer(bh); |
| } |
| put_bh(bh); /* One for getblk() */ |
| jbd2_journal_put_journal_head(descriptor); |
| |
| return (ret == -EIO); |
| } |
| |
| static void journal_do_submit_data(struct buffer_head **wbuf, int bufs) |
| { |
| int i; |
| |
| for (i = 0; i < bufs; i++) { |
| wbuf[i]->b_end_io = end_buffer_write_sync; |
| /* We use-up our safety reference in submit_bh() */ |
| submit_bh(WRITE, wbuf[i]); |
| } |
| } |
| |
| /* |
| * Submit all the data buffers to disk |
| */ |
| static void journal_submit_data_buffers(journal_t *journal, |
| transaction_t *commit_transaction) |
| { |
| struct journal_head *jh; |
| struct buffer_head *bh; |
| int locked; |
| int bufs = 0; |
| struct buffer_head **wbuf = journal->j_wbuf; |
| |
| /* |
| * 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 (test_set_buffer_locked(bh)) { |
| BUFFER_TRACE(bh, "needs blocking lock"); |
| spin_unlock(&journal->j_list_lock); |
| /* Write out all data to prevent deadlocks */ |
| journal_do_submit_data(wbuf, bufs); |
| 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) |
| || 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"); |
| put_bh(bh); |
| continue; |
| } |
| if (locked && test_clear_buffer_dirty(bh)) { |
| BUFFER_TRACE(bh, "needs writeout, adding to array"); |
| wbuf[bufs++] = bh; |
| __jbd2_journal_file_buffer(jh, commit_transaction, |
| BJ_Locked); |
| jbd_unlock_bh_state(bh); |
| if (bufs == journal->j_wbufsize) { |
| spin_unlock(&journal->j_list_lock); |
| journal_do_submit_data(wbuf, bufs); |
| bufs = 0; |
| goto write_out_data; |
| } |
| } |
| else { |
| BUFFER_TRACE(bh, "writeout complete: unfile"); |
| __jbd2_journal_unfile_buffer(jh); |
| jbd_unlock_bh_state(bh); |
| if (locked) |
| unlock_buffer(bh); |
| jbd2_journal_remove_journal_head(bh); |
| /* Once for our safety reference, once for |
| * jbd2_journal_remove_journal_head() */ |
| put_bh(bh); |
| put_bh(bh); |
| } |
| |
| if (lock_need_resched(&journal->j_list_lock)) { |
| spin_unlock(&journal->j_list_lock); |
| goto write_out_data; |
| } |
| } |
| spin_unlock(&journal->j_list_lock); |
| journal_do_submit_data(wbuf, bufs); |
| } |
| |
| static inline void write_tag_block(int tag_bytes, journal_block_tag_t *tag, |
| sector_t block) |
| { |
| tag->t_blocknr = cpu_to_be32(block & (u32)~0); |
| if (tag_bytes > JBD_TAG_SIZE32) |
| tag->t_blocknr_high = cpu_to_be32((block >> 31) >> 1); |
| } |
| |
| /* |
| * 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) |
| { |
| transaction_t *commit_transaction; |
| struct journal_head *jh, *new_jh, *descriptor; |
| struct buffer_head **wbuf = journal->j_wbuf; |
| int bufs; |
| int flags; |
| int err; |
| sector_t blocknr; |
| 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); |
| |
| /* |
| * First job: lock down the current transaction and wait for |
| * all outstanding updates to complete. |
| */ |
| |
| #ifdef COMMIT_STATS |
| spin_lock(&journal->j_list_lock); |
| summarise_journal_usage(journal); |
| spin_unlock(&journal->j_list_lock); |
| #endif |
| |
| /* 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"); |
| jbd2_journal_update_superblock(journal, 1); |
| } 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; |
| J_ASSERT(commit_transaction->t_state == T_RUNNING); |
| |
| jbd_debug(1, "JBD: starting commit of transaction %d\n", |
| commit_transaction->t_tid); |
| |
| spin_lock(&journal->j_state_lock); |
| commit_transaction->t_state = T_LOCKED; |
| |
| 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 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 permissable. |
| */ |
| 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_slab_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, "JBD: commit phase 1\n"); |
| |
| /* |
| * Switch to a new revoke table. |
| */ |
| jbd2_journal_switch_revoke_table(journal); |
| |
| commit_transaction->t_state = T_FLUSH; |
| journal->j_committing_transaction = commit_transaction; |
| journal->j_running_transaction = NULL; |
| 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"); |
| |
| /* |
| * First, drop modified flag: all accesses to the buffers |
| * will be tracked for a new trasaction only -bzzz |
| */ |
| spin_lock(&journal->j_list_lock); |
| if (commit_transaction->t_buffers) { |
| new_jh = jh = commit_transaction->t_buffers->b_tnext; |
| do { |
| J_ASSERT_JH(new_jh, new_jh->b_modified == 1 || |
| new_jh->b_modified == 0); |
| new_jh->b_modified = 0; |
| new_jh = new_jh->b_tnext; |
| } while (new_jh != jh); |
| } |
| spin_unlock(&journal->j_list_lock); |
| |
| /* |
| * Now start flushing things to disk, in the order they appear |
| * on the transaction lists. Data blocks go first. |
| */ |
| err = 0; |
| journal_submit_data_buffers(journal, commit_transaction); |
| |
| /* |
| * 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); |
| if (unlikely(!buffer_uptodate(bh))) |
| err = -EIO; |
| spin_lock(&journal->j_list_lock); |
| } |
| if (!inverted_lock(journal, bh)) { |
| put_bh(bh); |
| spin_lock(&journal->j_list_lock); |
| continue; |
| } |
| if (buffer_jbd(bh) && jh->b_jlist == BJ_Locked) { |
| __jbd2_journal_unfile_buffer(jh); |
| jbd_unlock_bh_state(bh); |
| jbd2_journal_remove_journal_head(bh); |
| put_bh(bh); |
| } else { |
| jbd_unlock_bh_state(bh); |
| } |
| put_bh(bh); |
| cond_resched_lock(&journal->j_list_lock); |
| } |
| spin_unlock(&journal->j_list_lock); |
| |
| if (err) |
| __jbd2_journal_abort_hard(journal); |
| |
| jbd2_journal_write_revoke_records(journal, commit_transaction); |
| |
| jbd_debug(3, "JBD: commit phase 2\n"); |
| |
| /* |
| * 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: |
| */ |
| commit_transaction->t_state = T_COMMIT; |
| |
| 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 for background writing. */ |
| |
| if (is_journal_aborted(journal)) { |
| JBUFFER_TRACE(jh, "journal is aborting: refile"); |
| 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) { |
| struct buffer_head *bh; |
| |
| J_ASSERT (bufs == 0); |
| |
| jbd_debug(4, "JBD: get descriptor\n"); |
| |
| descriptor = jbd2_journal_get_descriptor_buffer(journal); |
| if (!descriptor) { |
| __jbd2_journal_abort_hard(journal); |
| 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(JBD2_MAGIC_NUMBER); |
| header->h_blocktype = cpu_to_be32(JBD2_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"); |
| jbd2_journal_file_buffer(descriptor, commit_transaction, |
| BJ_LogCtl); |
| } |
| |
| /* 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_hard(journal); |
| 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. |
| */ |
| 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. */ |
| atomic_inc(&jh2bh(jh)->b_count); |
| |
| /* 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_bit(BH_JWrite, &jh2bh(jh)->b_state); |
| /* |
| * akpm: jbd2_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 = jbd2_journal_write_metadata_buffer(commit_transaction, |
| jh, &new_jh, blocknr); |
| set_bit(BH_JWrite, &jh2bh(new_jh)->b_state); |
| wbuf[bufs++] = jh2bh(new_jh); |
| |
| /* 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(tag_bytes, tag, jh2bh(jh)->b_blocknr); |
| tag->t_flags = cpu_to_be32(tag_flag); |
| tagp += tag_bytes; |
| space_left -= tag_bytes; |
| |
| 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) { |
| |
| 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(JBD2_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; |
| submit_bh(WRITE, bh); |
| } |
| cond_resched(); |
| |
| /* Force a new descriptor to be generated next |
| time round the loop. */ |
| descriptor = NULL; |
| bufs = 0; |
| } |
| } |
| |
| /* 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"); |
| jbd2_journal_unfile_buffer(journal, jh); |
| |
| /* |
| * ->t_iobuf_list should contain only dummy buffer_heads |
| * which were created by jbd2_journal_write_metadata_buffer(). |
| */ |
| BUFFER_TRACE(bh, "dumping temporary bh"); |
| jbd2_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_bit(BH_JWrite, &bh->b_state); |
| 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"); |
| jbd2_journal_file_buffer(jh, commit_transaction, BJ_Forget); |
| /* Wake up any transactions which were waiting for this |
| IO to complete */ |
| 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); |
| jbd2_journal_unfile_buffer(journal, jh); |
| jbd2_journal_put_journal_head(jh); |
| __brelse(bh); /* One for getblk */ |
| /* AKPM: bforget here */ |
| } |
| |
| jbd_debug(3, "JBD: commit phase 6\n"); |
| |
| if (journal_write_commit_record(journal, commit_transaction)) |
| err = -EIO; |
| |
| if (err) |
| __jbd2_journal_abort_hard(journal); |
| |
| /* 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; |
| |
| jh = commit_transaction->t_forget; |
| spin_unlock(&journal->j_list_lock); |
| bh = jh2bh(jh); |
| 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) { |
| jbd2_slab_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) { |
| jbd2_slab_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"); |
| __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 may end up still |
| * being dirty here, but we want to avoid writing back |
| * that buffer in the future now that the last use has |
| * been committed. That's not only a performance gain, |
| * it also stops aliasing problems if the buffer is left |
| * behind for writeback and gets reallocated for another |
| * use in a different page. */ |
| if (buffer_freed(bh)) { |
| clear_buffer_freed(bh); |
| clear_buffer_jbddirty(bh); |
| } |
| |
| if (buffer_jbddirty(bh)) { |
| JBUFFER_TRACE(jh, "add to new checkpointing trans"); |
| __jbd2_journal_insert_checkpoint(jh, commit_transaction); |
| JBUFFER_TRACE(jh, "refile for checkpoint writeback"); |
| __jbd2_journal_refile_buffer(jh); |
| jbd_unlock_bh_state(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. */ |
| JBUFFER_TRACE(jh, "refile or unfile freed buffer"); |
| __jbd2_journal_refile_buffer(jh); |
| if (!jh->b_transaction) { |
| jbd_unlock_bh_state(bh); |
| /* needs a brelse */ |
| jbd2_journal_remove_journal_head(bh); |
| release_buffer_page(bh); |
| } else |
| jbd_unlock_bh_state(bh); |
| } |
| cond_resched_lock(&journal->j_list_lock); |
| } |
| spin_unlock(&journal->j_list_lock); |
| /* |
| * This is a bit sleazy. We borrow j_list_lock to protect |
| * journal->j_committing_transaction in __jbd2_journal_remove_checkpoint. |
| * Really, __jbd2_journal_remove_checkpoint should be using j_state_lock but |
| * it's a bit hassle to hold that across __jbd2_journal_remove_checkpoint |
| */ |
| 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); |
| |
| 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; |
| spin_unlock(&journal->j_state_lock); |
| |
| if (commit_transaction->t_checkpoint_list == NULL) { |
| __jbd2_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); |
| |
| 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); |
| } |