diff options
Diffstat (limited to 'fs/jbd2/commit.c')
| -rw-r--r-- | fs/jbd2/commit.c | 1214 |
1 files changed, 1214 insertions, 0 deletions
diff --git a/fs/jbd2/commit.c b/fs/jbd2/commit.c new file mode 100644 index 000000000..db137671a --- /dev/null +++ b/fs/jbd2/commit.c @@ -0,0 +1,1214 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * linux/fs/jbd2/commit.c + * + * Written by Stephen C. Tweedie <sct@redhat.com>, 1998 + * + * Copyright 1998 Red Hat corp --- All Rights Reserved + * + * 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; + + get_page(page); + __brelse(bh); + try_to_free_buffers(page); + unlock_page(page); + put_page(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 timespec64 now; + + *cbh = NULL; + + if (is_journal_aborted(journal)) + return 0; + + bh = jbd2_journal_get_descriptor_buffer(commit_transaction, + JBD2_COMMIT_BLOCK); + if (!bh) + return 1; + + tmp = (struct commit_header *)bh->b_data; + ktime_get_coarse_real_ts64(&now); + tmp->h_commit_sec = cpu_to_be64(now.tv_sec); + tmp->h_commit_nsec = cpu_to_be32(now.tv_nsec); + + if (jbd2_has_feature_checksum(journal)) { + 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_feature_async_commit(journal)) + ret = submit_bh(REQ_OP_WRITE, + REQ_SYNC | REQ_PREFLUSH | REQ_FUA, bh); + else + ret = submit_bh(REQ_OP_WRITE, REQ_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 delayed allocation we may be doing + * block allocation in writepages(). + */ +int jbd2_journal_submit_inode_data_buffers(struct jbd2_inode *jinode) +{ + struct address_space *mapping = jinode->i_vfs_inode->i_mapping; + struct writeback_control wbc = { + .sync_mode = WB_SYNC_ALL, + .nr_to_write = mapping->nrpages * 2, + .range_start = jinode->i_dirty_start, + .range_end = jinode->i_dirty_end, + }; + + /* + * 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. + */ + return generic_writepages(mapping, &wbc); +} + +/* Send all the data buffers related to an inode */ +int jbd2_submit_inode_data(struct jbd2_inode *jinode) +{ + + if (!jinode || !(jinode->i_flags & JI_WRITE_DATA)) + return 0; + + trace_jbd2_submit_inode_data(jinode->i_vfs_inode); + return jbd2_journal_submit_inode_data_buffers(jinode); + +} +EXPORT_SYMBOL(jbd2_submit_inode_data); + +int jbd2_wait_inode_data(journal_t *journal, struct jbd2_inode *jinode) +{ + if (!jinode || !(jinode->i_flags & JI_WAIT_DATA) || + !jinode->i_vfs_inode || !jinode->i_vfs_inode->i_mapping) + return 0; + return filemap_fdatawait_range_keep_errors( + jinode->i_vfs_inode->i_mapping, jinode->i_dirty_start, + jinode->i_dirty_end); +} +EXPORT_SYMBOL(jbd2_wait_inode_data); + +/* + * 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; + + spin_lock(&journal->j_list_lock); + list_for_each_entry(jinode, &commit_transaction->t_inode_list, i_list) { + if (!(jinode->i_flags & JI_WRITE_DATA)) + continue; + jinode->i_flags |= JI_COMMIT_RUNNING; + spin_unlock(&journal->j_list_lock); + /* submit the inode data buffers. */ + trace_jbd2_submit_inode_data(jinode->i_vfs_inode); + if (journal->j_submit_inode_data_buffers) { + err = journal->j_submit_inode_data_buffers(jinode); + if (!ret) + ret = err; + } + spin_lock(&journal->j_list_lock); + J_ASSERT(jinode->i_transaction == commit_transaction); + jinode->i_flags &= ~JI_COMMIT_RUNNING; + smp_mb(); + wake_up_bit(&jinode->i_flags, __JI_COMMIT_RUNNING); + } + spin_unlock(&journal->j_list_lock); + return ret; +} + +int jbd2_journal_finish_inode_data_buffers(struct jbd2_inode *jinode) +{ + struct address_space *mapping = jinode->i_vfs_inode->i_mapping; + + return filemap_fdatawait_range_keep_errors(mapping, + jinode->i_dirty_start, + jinode->i_dirty_end); +} + +/* + * 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) { + if (!(jinode->i_flags & JI_WAIT_DATA)) + continue; + jinode->i_flags |= JI_COMMIT_RUNNING; + spin_unlock(&journal->j_list_lock); + /* wait for the inode data buffers writeout. */ + if (journal->j_finish_inode_data_buffers) { + err = journal->j_finish_inode_data_buffers(jinode); + if (!ret) + ret = err; + } + cond_resched(); + spin_lock(&journal->j_list_lock); + jinode->i_flags &= ~JI_COMMIT_RUNNING; + smp_mb(); + 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; + jinode->i_dirty_start = 0; + jinode->i_dirty_end = 0; + } + } + 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_feature_64bit(j)) + tag->t_blocknr_high = cpu_to_be32((block >> 31) >> 1); +} + +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_feature_csum3(j)) + 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_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_io(&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, + REQ_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); + + write_lock(&journal->j_state_lock); + journal->j_flags |= JBD2_FULL_COMMIT_ONGOING; + while (journal->j_flags & JBD2_FAST_COMMIT_ONGOING) { + DEFINE_WAIT(wait); + + prepare_to_wait(&journal->j_fc_wait, &wait, + TASK_UNINTERRUPTIBLE); + write_unlock(&journal->j_state_lock); + schedule(); + write_lock(&journal->j_state_lock); + finish_wait(&journal->j_fc_wait, &wait); + /* + * TODO: by blocking fast commits here, we are increasing + * fsync() latency slightly. Strictly speaking, we don't need + * to block fast commits until the transaction enters T_FLUSH + * state. So an optimization is possible where we block new fast + * commits here and wait for existing ones to complete + * just before we enter T_FLUSH. That way, the existing fast + * commits and this full commit can proceed parallely. + */ + } + write_unlock(&journal->j_state_lock); + + 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); + journal->j_fc_off = 0; + 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); + commit_transaction->t_state = T_SWITCH; + + 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. + * We use journal->j_state_lock here to serialize processing of + * t_reserved_list with eviction of buffers from journal_unmap_buffer(). + */ + 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); + + spin_lock(&jh->b_state_lock); + jbd2_free(jh->b_committed_data, bh->b_size); + jh->b_committed_data = NULL; + spin_unlock(&jh->b_state_lock); + } + jbd2_journal_refile_buffer(journal, jh); + } + + write_unlock(&journal->j_state_lock); + /* + * 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, false); + 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); + + write_lock(&journal->j_state_lock); + /* + * 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_all(&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(commit_transaction, &log_bufs); + + 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 = commit_transaction->t_nr_buffers; + 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( + commit_transaction, + JBD2_DESCRIPTOR_BLOCK); + 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); + 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. + */ + 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); +start_journal_io: + if (descriptor) + jbd2_descriptor_block_csum_set(journal, + descriptor); + + for (i = 0; i < bufs; i++) { + struct buffer_head *bh = wbuf[i]; + /* + * Compute checksum. + */ + if (jbd2_has_feature_checksum(journal)) { + 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(REQ_OP_WRITE, REQ_SYNC, bh); + } + cond_resched(); + + /* 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 < jbd2_journal_get_max_txn_bufs(journal)) + 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); + + /* Done it all: now write the commit record asynchronously. */ + if (jbd2_has_feature_async_commit(journal)) { + err = journal_submit_commit_record(journal, commit_transaction, + &cbh, crc32_sum); + if (err) + jbd2_journal_abort(journal, err); + } + + 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); + stats.run.rs_blocks_logged++; + + /* + * 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); + stats.run.rs_blocks_logged++; + __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_feature_async_commit(journal)) { + err = journal_submit_commit_record(journal, commit_transaction, + &cbh, crc32_sum); + if (err) + jbd2_journal_abort(journal, err); + } + if (cbh) + err = journal_wait_on_commit_record(journal, cbh); + stats.run.rs_blocks_logged++; + if (jbd2_has_feature_async_commit(journal) && + journal->j_flags & JBD2_BARRIER) { + blkdev_issue_flush(journal->j_dev, GFP_NOFS); + } + + if (err) + jbd2_journal_abort(journal, err); + + WARN_ON_ONCE( + atomic_read(&commit_transaction->t_outstanding_credits) < 0); + + /* + * 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; + bool drop_ref; + + 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); + spin_lock(&jh->b_state_lock); + 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, 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. + */ + if (buffer_freed(bh) && !jh->b_next_transaction) { + struct address_space *mapping; + + clear_buffer_freed(bh); + clear_buffer_jbddirty(bh); + + /* + * Block device buffers need to stay mapped all the + * time, so it is enough to clear buffer_jbddirty and + * buffer_freed bits. For the file mapping buffers (i.e. + * journalled data) we need to unmap buffer and clear + * more bits. We also need to be careful about the check + * because the data page mapping can get cleared under + * our hands. Note that if mapping == NULL, we don't + * need to make buffer unmapped because the page is + * already detached from the mapping and buffers cannot + * get reused. + */ + mapping = READ_ONCE(bh->b_page->mapping); + if (mapping && !sb_is_blkdev_sb(mapping->host->i_sb)) { + 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"); + drop_ref = __jbd2_journal_refile_buffer(jh); + spin_unlock(&jh->b_state_lock); + if (drop_ref) + jbd2_journal_put_journal_head(jh); + 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); + if (journal->j_fc_cleanup_callback) + journal->j_fc_cleanup_callback(journal, 1); + + 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); + journal->j_flags &= ~JBD2_FULL_COMMIT_ONGOING; + journal->j_flags &= ~JBD2_FAST_COMMIT_ONGOING; + 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); + wake_up(&journal->j_fc_wait); + + /* + * 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); +} |