From: Simon Glass <simon.glass@canonical.com> Add the JBD2 journaling layer recovery and commit functionality from the Linux 6.18 kernel ext4 filesystem driver. recovery.c handles: - Journal recovery after unclean shutdown - Transaction replay and verification - Descriptor block parsing - Revoke block processing commit.c handles: - Transaction commit processing - Descriptor block writing - Data and metadata buffer submission - Checksum calculation for journal blocks These files are needed for journal integrity and crash recovery in the ext4 filesystem. Co-developed-by: Claude Opus 4.5 <noreply@anthropic.com> Signed-off-by: Simon Glass <simon.glass@canonical.com> --- fs/jbd2/commit.c | 1160 ++++++++++++++++++++++++++++++++++++++++++++ fs/jbd2/recovery.c | 996 +++++++++++++++++++++++++++++++++++++ 2 files changed, 2156 insertions(+) create mode 100644 fs/jbd2/commit.c create mode 100644 fs/jbd2/recovery.c diff --git a/fs/jbd2/commit.c b/fs/jbd2/commit.c new file mode 100644 index 00000000000..7203d2d2624 --- /dev/null +++ b/fs/jbd2/commit.c @@ -0,0 +1,1160 @@ +// 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 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 folio *folio; + + if (buffer_dirty(bh)) + goto nope; + if (atomic_read(&bh->b_count) != 1) + goto nope; + folio = bh->b_folio; + if (folio->mapping) + goto nope; + + /* OK, it's a truncated page */ + if (!folio_trylock(folio)) + goto nope; + + folio_get(folio); + __brelse(bh); + try_to_free_buffers(folio); + folio_unlock(folio); + folio_put(folio); + 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_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; + struct timespec64 now; + blk_opf_t write_flags = REQ_OP_WRITE | JBD2_JOURNAL_REQ_FLAGS; + + *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)) + write_flags |= REQ_PREFLUSH | REQ_FUA; + + submit_bh(write_flags, bh); + *cbh = bh; + return 0; +} + +/* + * 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; +} + +/* Send all the data buffers related to an inode */ +int jbd2_submit_inode_data(journal_t *journal, struct jbd2_inode *jinode) +{ + if (!jinode || !(jinode->i_flags & JI_WRITE_DATA)) + return 0; + + trace_jbd2_submit_inode_data(jinode->i_vfs_inode); + return journal->j_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) +{ + char *addr; + __u32 checksum; + + addr = kmap_local_folio(bh->b_folio, bh_offset(bh)); + checksum = crc32_be(crc32_sum, addr, bh->b_size); + kunmap_local(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; + __u8 *addr; + __u32 csum32; + __be32 seq; + + if (!jbd2_journal_has_csum_v2or3(j)) + return; + + seq = cpu_to_be32(sequence); + addr = kmap_local_folio(bh->b_folio, bh_offset(bh)); + csum32 = jbd2_chksum(j->j_csum_seed, (__u8 *)&seq, sizeof(seq)); + csum32 = jbd2_chksum(csum32, addr, bh->b_size); + kunmap_local(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 escape; + 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) { + jbd2_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, 0); + mutex_unlock(&journal->j_checkpoint_mutex); + } else { + jbd2_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); + jbd2_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); + + // waits for any t_updates to finish + jbd2_journal_wait_updates(journal); + + 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, JBD2_SHRINK_BUSY_STOP); + spin_unlock(&journal->j_list_lock); + + jbd2_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); + + jbd2_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); + + jbd2_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)); + + 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); + + jbd2_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; + } + + jbd2_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"); + escape = jbd2_journal_write_metadata_buffer(commit_transaction, + jh, &wbuf[bufs], blocknr); + jbd2_file_log_bh(&io_bufs, wbuf[bufs]); + + /* Record the new block's tag in the current descriptor + buffer */ + + tag_flag = 0; + if (escape) + 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) { + + jbd2_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 | JBD2_JOURNAL_REQ_FLAGS, + 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 %d while flushing file data on %s\n", + err, journal->j_devname); + err = 0; + } + + /* + * Get current oldest transaction in the log before we issue flush + * to the filesystem device. After the flush we can be sure that + * blocks of all older transactions are checkpointed to persistent + * storage and we will be safe to update journal start in the + * superblock with the numbers we get here. + */ + update_tail = + jbd2_journal_get_log_tail(journal, &first_tid, &first_block); + + write_lock(&journal->j_state_lock); + if (update_tail) { + long freed = first_block - journal->j_tail; + + if (first_block < journal->j_tail) + freed += journal->j_last - journal->j_first; + /* Update tail only if we free significant amount of space */ + if (freed < journal->j_max_transaction_buffers) + 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 and update the journal tail sequence. + */ + if ((commit_transaction->t_need_data_flush || update_tail) && + (journal->j_fs_dev != journal->j_dev) && + (journal->j_flags & JBD2_BARRIER)) + blkdev_issue_flush(journal->j_fs_dev); + + /* 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. + */ + + jbd2_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); + + jbd2_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); + + jbd2_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); + } + + 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. */ + + jbd2_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_folio->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! */ + + jbd2_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); + WRITE_ONCE(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, commit_transaction->t_tid); + + trace_jbd2_end_commit(journal, commit_transaction); + jbd2_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) { + __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); +} diff --git a/fs/jbd2/recovery.c b/fs/jbd2/recovery.c new file mode 100644 index 00000000000..cac8c2cd4a9 --- /dev/null +++ b/fs/jbd2/recovery.c @@ -0,0 +1,996 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * linux/fs/jbd2/recovery.c + * + * Written by Stephen C. Tweedie <sct@redhat.com>, 1999 + * + * Copyright 1999-2000 Red Hat Software --- All Rights Reserved + * + * Journal recovery routines for the generic filesystem journaling code; + * part of the ext2fs journaling system. + */ + +#ifndef __KERNEL__ +#include "jfs_user.h" +#else +#include <linux/time.h> +#include <linux/fs.h> +#include <linux/jbd2.h> +#include <linux/errno.h> +#include <linux/crc32.h> +#include <linux/blkdev.h> +#include <linux/string_choices.h> +#endif + +/* + * Maintain information about the progress of the recovery job, so that + * the different passes can carry information between them. + */ +struct recovery_info +{ + tid_t start_transaction; + tid_t end_transaction; + unsigned long head_block; + + int nr_replays; + int nr_revokes; + int nr_revoke_hits; +}; + +static int do_one_pass(journal_t *journal, + struct recovery_info *info, enum passtype pass); +static int scan_revoke_records(journal_t *, enum passtype, struct buffer_head *, + tid_t, struct recovery_info *); + +#ifdef __KERNEL__ + +/* Release readahead buffers after use */ +static void journal_brelse_array(struct buffer_head *b[], int n) +{ + while (--n >= 0) + brelse (b[n]); +} + + +/* + * When reading from the journal, we are going through the block device + * layer directly and so there is no readahead being done for us. We + * need to implement any readahead ourselves if we want it to happen at + * all. Recovery is basically one long sequential read, so make sure we + * do the IO in reasonably large chunks. + * + * This is not so critical that we need to be enormously clever about + * the readahead size, though. 128K is a purely arbitrary, good-enough + * fixed value. + */ + +#define MAXBUF 8 +static void do_readahead(journal_t *journal, unsigned int start) +{ + unsigned int max, nbufs, next; + unsigned long long blocknr; + struct buffer_head *bh; + + struct buffer_head * bufs[MAXBUF]; + + /* Do up to 128K of readahead */ + max = start + (128 * 1024 / journal->j_blocksize); + if (max > journal->j_total_len) + max = journal->j_total_len; + + /* Do the readahead itself. We'll submit MAXBUF buffer_heads at + * a time to the block device IO layer. */ + + nbufs = 0; + + for (next = start; next < max; next++) { + int err = jbd2_journal_bmap(journal, next, &blocknr); + + if (err) { + printk(KERN_ERR "JBD2: bad block at offset %u\n", + next); + goto failed; + } + + bh = __getblk(journal->j_dev, blocknr, journal->j_blocksize); + if (!bh) + goto failed; + + if (!buffer_uptodate(bh) && !buffer_locked(bh)) { + bufs[nbufs++] = bh; + if (nbufs == MAXBUF) { + bh_readahead_batch(nbufs, bufs, 0); + journal_brelse_array(bufs, nbufs); + nbufs = 0; + } + } else + brelse(bh); + } + + if (nbufs) + bh_readahead_batch(nbufs, bufs, 0); + +failed: + if (nbufs) + journal_brelse_array(bufs, nbufs); +} + +#endif /* __KERNEL__ */ + + +/* + * Read a block from the journal + */ + +static int jread(struct buffer_head **bhp, journal_t *journal, + unsigned int offset) +{ + int err; + unsigned long long blocknr; + struct buffer_head *bh; + + *bhp = NULL; + + if (offset >= journal->j_total_len) { + printk(KERN_ERR "JBD2: corrupted journal superblock\n"); + return -EFSCORRUPTED; + } + + err = jbd2_journal_bmap(journal, offset, &blocknr); + + if (err) { + printk(KERN_ERR "JBD2: bad block at offset %u\n", + offset); + return err; + } + + bh = __getblk(journal->j_dev, blocknr, journal->j_blocksize); + if (!bh) + return -ENOMEM; + + if (!buffer_uptodate(bh)) { + /* + * If this is a brand new buffer, start readahead. + * Otherwise, we assume we are already reading it. + */ + bool need_readahead = !buffer_req(bh); + + bh_read_nowait(bh, 0); + if (need_readahead) + do_readahead(journal, offset); + wait_on_buffer(bh); + } + + if (!buffer_uptodate(bh)) { + printk(KERN_ERR "JBD2: Failed to read block at offset %u\n", + offset); + brelse(bh); + return -EIO; + } + + *bhp = bh; + return 0; +} + +static int jbd2_descriptor_block_csum_verify(journal_t *j, void *buf) +{ + struct jbd2_journal_block_tail *tail; + __be32 provided; + __u32 calculated; + + if (!jbd2_journal_has_csum_v2or3(j)) + return 1; + + tail = (struct jbd2_journal_block_tail *)((char *)buf + + j->j_blocksize - sizeof(struct jbd2_journal_block_tail)); + provided = tail->t_checksum; + tail->t_checksum = 0; + calculated = jbd2_chksum(j->j_csum_seed, buf, j->j_blocksize); + tail->t_checksum = provided; + + return provided == cpu_to_be32(calculated); +} + +/* + * Count the number of in-use tags in a journal descriptor block. + */ + +static int count_tags(journal_t *journal, struct buffer_head *bh) +{ + char * tagp; + journal_block_tag_t tag; + int nr = 0, size = journal->j_blocksize; + int tag_bytes = journal_tag_bytes(journal); + + if (jbd2_journal_has_csum_v2or3(journal)) + size -= sizeof(struct jbd2_journal_block_tail); + + tagp = &bh->b_data[sizeof(journal_header_t)]; + + while ((tagp - bh->b_data + tag_bytes) <= size) { + memcpy(&tag, tagp, sizeof(tag)); + + nr++; + tagp += tag_bytes; + if (!(tag.t_flags & cpu_to_be16(JBD2_FLAG_SAME_UUID))) + tagp += 16; + + if (tag.t_flags & cpu_to_be16(JBD2_FLAG_LAST_TAG)) + break; + } + + return nr; +} + + +/* Make sure we wrap around the log correctly! */ +#define wrap(journal, var) \ +do { \ + if (var >= (journal)->j_last) \ + var -= ((journal)->j_last - (journal)->j_first); \ +} while (0) + +static int fc_do_one_pass(journal_t *journal, + struct recovery_info *info, enum passtype pass) +{ + unsigned int expected_commit_id = info->end_transaction; + unsigned long next_fc_block; + struct buffer_head *bh; + int err = 0; + + next_fc_block = journal->j_fc_first; + if (!journal->j_fc_replay_callback) + return 0; + + while (next_fc_block <= journal->j_fc_last) { + jbd2_debug(3, "Fast commit replay: next block %ld\n", + next_fc_block); + err = jread(&bh, journal, next_fc_block); + if (err) { + jbd2_debug(3, "Fast commit replay: read error\n"); + break; + } + + err = journal->j_fc_replay_callback(journal, bh, pass, + next_fc_block - journal->j_fc_first, + expected_commit_id); + brelse(bh); + next_fc_block++; + if (err < 0 || err == JBD2_FC_REPLAY_STOP) + break; + err = 0; + } + + if (err) + jbd2_debug(3, "Fast commit replay failed, err = %d\n", err); + + return err; +} + +/** + * jbd2_journal_recover - recovers a on-disk journal + * @journal: the journal to recover + * + * The primary function for recovering the log contents when mounting a + * journaled device. + * + * Recovery is done in three passes. In the first pass, we look for the + * end of the log. In the second, we assemble the list of revoke + * blocks. In the third and final pass, we replay any un-revoked blocks + * in the log. + */ +int jbd2_journal_recover(journal_t *journal) +{ + int err, err2; + struct recovery_info info; + + memset(&info, 0, sizeof(info)); + + /* + * The journal superblock's s_start field (the current log head) + * is always zero if, and only if, the journal was cleanly + * unmounted. We use its in-memory version j_tail here because + * jbd2_journal_wipe() could have updated it without updating journal + * superblock. + */ + if (!journal->j_tail) { + journal_superblock_t *sb = journal->j_superblock; + + jbd2_debug(1, "No recovery required, last transaction %d, head block %u\n", + be32_to_cpu(sb->s_sequence), be32_to_cpu(sb->s_head)); + journal->j_transaction_sequence = be32_to_cpu(sb->s_sequence) + 1; + journal->j_head = be32_to_cpu(sb->s_head); + return 0; + } + + err = do_one_pass(journal, &info, PASS_SCAN); + if (!err) + err = do_one_pass(journal, &info, PASS_REVOKE); + if (!err) + err = do_one_pass(journal, &info, PASS_REPLAY); + + jbd2_debug(1, "JBD2: recovery, exit status %d, " + "recovered transactions %u to %u\n", + err, info.start_transaction, info.end_transaction); + jbd2_debug(1, "JBD2: Replayed %d and revoked %d/%d blocks\n", + info.nr_replays, info.nr_revoke_hits, info.nr_revokes); + + /* Restart the log at the next transaction ID, thus invalidating + * any existing commit records in the log. */ + journal->j_transaction_sequence = ++info.end_transaction; + journal->j_head = info.head_block; + jbd2_debug(1, "JBD2: last transaction %d, head block %lu\n", + journal->j_transaction_sequence, journal->j_head); + + jbd2_journal_clear_revoke(journal); + /* Free revoke table allocated for replay */ + if (journal->j_revoke != journal->j_revoke_table[0] && + journal->j_revoke != journal->j_revoke_table[1]) { + jbd2_journal_destroy_revoke_table(journal->j_revoke); + journal->j_revoke = journal->j_revoke_table[1]; + } + err2 = sync_blockdev(journal->j_fs_dev); + if (!err) + err = err2; + err2 = jbd2_check_fs_dev_write_error(journal); + if (!err) + err = err2; + /* Make sure all replayed data is on permanent storage */ + if (journal->j_flags & JBD2_BARRIER) { + err2 = blkdev_issue_flush(journal->j_fs_dev); + if (!err) + err = err2; + } + return err; +} + +/** + * jbd2_journal_skip_recovery - Start journal and wipe exiting records + * @journal: journal to startup + * + * Locate any valid recovery information from the journal and set up the + * journal structures in memory to ignore it (presumably because the + * caller has evidence that it is out of date). + * This function doesn't appear to be exported.. + * + * We perform one pass over the journal to allow us to tell the user how + * much recovery information is being erased, and to let us initialise + * the journal transaction sequence numbers to the next unused ID. + */ +int jbd2_journal_skip_recovery(journal_t *journal) +{ + int err; + + struct recovery_info info; + + memset (&info, 0, sizeof(info)); + + err = do_one_pass(journal, &info, PASS_SCAN); + + if (err) { + printk(KERN_ERR "JBD2: error %d scanning journal\n", err); + ++journal->j_transaction_sequence; + journal->j_head = journal->j_first; + } else { +#ifdef CONFIG_JBD2_DEBUG + int dropped = info.end_transaction - + be32_to_cpu(journal->j_superblock->s_sequence); + jbd2_debug(1, + "JBD2: ignoring %d transaction%s from the journal.\n", + dropped, str_plural(dropped)); +#endif + journal->j_transaction_sequence = ++info.end_transaction; + journal->j_head = info.head_block; + } + + journal->j_tail = 0; + return err; +} + +static inline unsigned long long read_tag_block(journal_t *journal, + journal_block_tag_t *tag) +{ + unsigned long long block = be32_to_cpu(tag->t_blocknr); + if (jbd2_has_feature_64bit(journal)) + block |= (u64)be32_to_cpu(tag->t_blocknr_high) << 32; + return block; +} + +/* + * calc_chksums calculates the checksums for the blocks described in the + * descriptor block. + */ +static int calc_chksums(journal_t *journal, struct buffer_head *bh, + unsigned long *next_log_block, __u32 *crc32_sum) +{ + int i, num_blks, err; + unsigned long io_block; + struct buffer_head *obh; + + num_blks = count_tags(journal, bh); + /* Calculate checksum of the descriptor block. */ + *crc32_sum = crc32_be(*crc32_sum, (void *)bh->b_data, bh->b_size); + + for (i = 0; i < num_blks; i++) { + io_block = (*next_log_block)++; + wrap(journal, *next_log_block); + err = jread(&obh, journal, io_block); + if (err) { + printk(KERN_ERR "JBD2: IO error %d recovering block " + "%lu in log\n", err, io_block); + return 1; + } else { + *crc32_sum = crc32_be(*crc32_sum, (void *)obh->b_data, + obh->b_size); + } + put_bh(obh); + } + return 0; +} + +static int jbd2_commit_block_csum_verify(journal_t *j, void *buf) +{ + struct commit_header *h; + __be32 provided; + __u32 calculated; + + if (!jbd2_journal_has_csum_v2or3(j)) + return 1; + + h = buf; + provided = h->h_chksum[0]; + h->h_chksum[0] = 0; + calculated = jbd2_chksum(j->j_csum_seed, buf, j->j_blocksize); + h->h_chksum[0] = provided; + + return provided == cpu_to_be32(calculated); +} + +static bool jbd2_commit_block_csum_verify_partial(journal_t *j, void *buf) +{ + struct commit_header *h; + __be32 provided; + __u32 calculated; + void *tmpbuf; + + tmpbuf = kzalloc(j->j_blocksize, GFP_KERNEL); + if (!tmpbuf) + return false; + + memcpy(tmpbuf, buf, sizeof(struct commit_header)); + h = tmpbuf; + provided = h->h_chksum[0]; + h->h_chksum[0] = 0; + calculated = jbd2_chksum(j->j_csum_seed, tmpbuf, j->j_blocksize); + kfree(tmpbuf); + + return provided == cpu_to_be32(calculated); +} + +static int jbd2_block_tag_csum_verify(journal_t *j, journal_block_tag_t *tag, + journal_block_tag3_t *tag3, + void *buf, __u32 sequence) +{ + __u32 csum32; + __be32 seq; + + if (!jbd2_journal_has_csum_v2or3(j)) + return 1; + + seq = cpu_to_be32(sequence); + csum32 = jbd2_chksum(j->j_csum_seed, (__u8 *)&seq, sizeof(seq)); + csum32 = jbd2_chksum(csum32, buf, j->j_blocksize); + + if (jbd2_has_feature_csum3(j)) + return tag3->t_checksum == cpu_to_be32(csum32); + else + return tag->t_checksum == cpu_to_be16(csum32); +} + +static __always_inline int jbd2_do_replay(journal_t *journal, + struct recovery_info *info, + struct buffer_head *bh, + unsigned long *next_log_block, + unsigned int next_commit_ID) +{ + char *tagp; + int flags; + int ret = 0; + int tag_bytes = journal_tag_bytes(journal); + int descr_csum_size = 0; + unsigned long io_block; + journal_block_tag_t tag; + struct buffer_head *obh; + struct buffer_head *nbh; + + if (jbd2_journal_has_csum_v2or3(journal)) + descr_csum_size = sizeof(struct jbd2_journal_block_tail); + + tagp = &bh->b_data[sizeof(journal_header_t)]; + while (tagp - bh->b_data + tag_bytes <= + journal->j_blocksize - descr_csum_size) { + int err; + + memcpy(&tag, tagp, sizeof(tag)); + flags = be16_to_cpu(tag.t_flags); + + io_block = (*next_log_block)++; + wrap(journal, *next_log_block); + err = jread(&obh, journal, io_block); + if (err) { + /* Recover what we can, but report failure at the end. */ + ret = err; + pr_err("JBD2: IO error %d recovering block %lu in log\n", + err, io_block); + } else { + unsigned long long blocknr; + + J_ASSERT(obh != NULL); + blocknr = read_tag_block(journal, &tag); + + /* If the block has been revoked, then we're all done here. */ + if (jbd2_journal_test_revoke(journal, blocknr, + next_commit_ID)) { + brelse(obh); + ++info->nr_revoke_hits; + goto skip_write; + } + + /* Look for block corruption */ + if (!jbd2_block_tag_csum_verify(journal, &tag, + (journal_block_tag3_t *)tagp, + obh->b_data, next_commit_ID)) { + brelse(obh); + ret = -EFSBADCRC; + pr_err("JBD2: Invalid checksum recovering data block %llu in journal block %lu\n", + blocknr, io_block); + goto skip_write; + } + + /* Find a buffer for the new data being restored */ + nbh = __getblk(journal->j_fs_dev, blocknr, + journal->j_blocksize); + if (nbh == NULL) { + pr_err("JBD2: Out of memory during recovery.\n"); + brelse(obh); + return -ENOMEM; + } + + lock_buffer(nbh); + memcpy(nbh->b_data, obh->b_data, journal->j_blocksize); + if (flags & JBD2_FLAG_ESCAPE) { + *((__be32 *)nbh->b_data) = + cpu_to_be32(JBD2_MAGIC_NUMBER); + } + + BUFFER_TRACE(nbh, "marking dirty"); + set_buffer_uptodate(nbh); + mark_buffer_dirty(nbh); + BUFFER_TRACE(nbh, "marking uptodate"); + ++info->nr_replays; + unlock_buffer(nbh); + brelse(obh); + brelse(nbh); + } + +skip_write: + tagp += tag_bytes; + if (!(flags & JBD2_FLAG_SAME_UUID)) + tagp += 16; + + if (flags & JBD2_FLAG_LAST_TAG) + break; + } + + return ret; +} + +static int do_one_pass(journal_t *journal, + struct recovery_info *info, enum passtype pass) +{ + unsigned int first_commit_ID, next_commit_ID; + unsigned long next_log_block, head_block; + int err, success = 0; + journal_superblock_t * sb; + journal_header_t * tmp; + struct buffer_head *bh = NULL; + unsigned int sequence; + int blocktype; + __u32 crc32_sum = ~0; /* Transactional Checksums */ + bool need_check_commit_time = false; + __u64 last_trans_commit_time = 0, commit_time; + + /* + * First thing is to establish what we expect to find in the log + * (in terms of transaction IDs), and where (in terms of log + * block offsets): query the superblock. + */ + + sb = journal->j_superblock; + next_commit_ID = be32_to_cpu(sb->s_sequence); + next_log_block = be32_to_cpu(sb->s_start); + head_block = next_log_block; + + first_commit_ID = next_commit_ID; + if (pass == PASS_SCAN) + info->start_transaction = first_commit_ID; + else if (pass == PASS_REVOKE) { + /* + * Would the default revoke table have too long hash chains + * during replay? + */ + if (info->nr_revokes > JOURNAL_REVOKE_DEFAULT_HASH * 16) { + unsigned int hash_size; + + /* + * Aim for average chain length of 8, limit at 1M + * entries to avoid problems with malicious + * filesystems. + */ + hash_size = min(roundup_pow_of_two(info->nr_revokes / 8), + 1U << 20); + journal->j_revoke = + jbd2_journal_init_revoke_table(hash_size); + if (!journal->j_revoke) { + printk(KERN_ERR + "JBD2: failed to allocate revoke table for replay with %u entries. " + "Journal replay may be slow.\n", hash_size); + journal->j_revoke = journal->j_revoke_table[1]; + } + } + } + + jbd2_debug(1, "Starting recovery pass %d\n", pass); + + /* + * Now we walk through the log, transaction by transaction, + * making sure that each transaction has a commit block in the + * expected place. Each complete transaction gets replayed back + * into the main filesystem. + */ + + while (1) { + cond_resched(); + + /* If we already know where to stop the log traversal, + * check right now that we haven't gone past the end of + * the log. */ + + if (pass != PASS_SCAN) + if (tid_geq(next_commit_ID, info->end_transaction)) + break; + + jbd2_debug(2, "Scanning for sequence ID %u at %lu/%lu\n", + next_commit_ID, next_log_block, journal->j_last); + + /* Skip over each chunk of the transaction looking + * either the next descriptor block or the final commit + * record. */ + + jbd2_debug(3, "JBD2: checking block %ld\n", next_log_block); + brelse(bh); + bh = NULL; + err = jread(&bh, journal, next_log_block); + if (err) + goto failed; + + next_log_block++; + wrap(journal, next_log_block); + + /* What kind of buffer is it? + * + * If it is a descriptor block, check that it has the + * expected sequence number. Otherwise, we're all done + * here. */ + + tmp = (journal_header_t *)bh->b_data; + + if (tmp->h_magic != cpu_to_be32(JBD2_MAGIC_NUMBER)) + break; + + blocktype = be32_to_cpu(tmp->h_blocktype); + sequence = be32_to_cpu(tmp->h_sequence); + jbd2_debug(3, "Found magic %d, sequence %d\n", + blocktype, sequence); + + if (sequence != next_commit_ID) + break; + + /* OK, we have a valid descriptor block which matches + * all of the sequence number checks. What are we going + * to do with it? That depends on the pass... */ + + switch(blocktype) { + case JBD2_DESCRIPTOR_BLOCK: + /* Verify checksum first */ + if (!jbd2_descriptor_block_csum_verify(journal, + bh->b_data)) { + /* + * PASS_SCAN can see stale blocks due to lazy + * journal init. Don't error out on those yet. + */ + if (pass != PASS_SCAN) { + pr_err("JBD2: Invalid checksum recovering block %lu in log\n", + next_log_block); + err = -EFSBADCRC; + goto failed; + } + need_check_commit_time = true; + jbd2_debug(1, + "invalid descriptor block found in %lu\n", + next_log_block); + } + + /* If it is a valid descriptor block, replay it + * in pass REPLAY; if journal_checksums enabled, then + * calculate checksums in PASS_SCAN, otherwise, + * just skip over the blocks it describes. */ + if (pass != PASS_REPLAY) { + if (pass == PASS_SCAN && + jbd2_has_feature_checksum(journal) && + !info->end_transaction) { + if (calc_chksums(journal, bh, + &next_log_block, + &crc32_sum)) + break; + continue; + } + next_log_block += count_tags(journal, bh); + wrap(journal, next_log_block); + continue; + } + + /* + * A descriptor block: we can now write all of the + * data blocks. Yay, useful work is finally getting + * done here! + */ + err = jbd2_do_replay(journal, info, bh, &next_log_block, + next_commit_ID); + if (err) { + if (err == -ENOMEM) + goto failed; + success = err; + } + + continue; + + case JBD2_COMMIT_BLOCK: + if (pass != PASS_SCAN) { + next_commit_ID++; + continue; + } + + /* How to differentiate between interrupted commit + * and journal corruption ? + * + * {nth transaction} + * Checksum Verification Failed + * | + * ____________________ + * | | + * async_commit sync_commit + * | | + * | GO TO NEXT "Journal Corruption" + * | TRANSACTION + * | + * {(n+1)th transanction} + * | + * _______|______________ + * | | + * Commit block found Commit block not found + * | | + * "Journal Corruption" | + * _____________|_________ + * | | + * nth trans corrupt OR nth trans + * and (n+1)th interrupted interrupted + * before commit block + * could reach the disk. + * (Cannot find the difference in above + * mentioned conditions. Hence assume + * "Interrupted Commit".) + */ + commit_time = be64_to_cpu( + ((struct commit_header *)bh->b_data)->h_commit_sec); + /* + * If need_check_commit_time is set, it means we are in + * PASS_SCAN and csum verify failed before. If + * commit_time is increasing, it's the same journal, + * otherwise it is stale journal block, just end this + * recovery. + */ + if (need_check_commit_time) { + if (commit_time >= last_trans_commit_time) { + pr_err("JBD2: Invalid checksum found in transaction %u\n", + next_commit_ID); + err = -EFSBADCRC; + goto failed; + } + ignore_crc_mismatch: + /* + * It likely does not belong to same journal, + * just end this recovery with success. + */ + jbd2_debug(1, "JBD2: Invalid checksum ignored in transaction %u, likely stale data\n", + next_commit_ID); + goto done; + } + + /* + * Found an expected commit block: if checksums + * are present, verify them in PASS_SCAN; else not + * much to do other than move on to the next sequence + * number. + */ + if (jbd2_has_feature_checksum(journal)) { + struct commit_header *cbh = + (struct commit_header *)bh->b_data; + unsigned found_chksum = + be32_to_cpu(cbh->h_chksum[0]); + + if (info->end_transaction) { + journal->j_failed_commit = + info->end_transaction; + break; + } + + /* Neither checksum match nor unused? */ + if (!((crc32_sum == found_chksum && + cbh->h_chksum_type == + JBD2_CRC32_CHKSUM && + cbh->h_chksum_size == + JBD2_CRC32_CHKSUM_SIZE) || + (cbh->h_chksum_type == 0 && + cbh->h_chksum_size == 0 && + found_chksum == 0))) + goto chksum_error; + + crc32_sum = ~0; + goto chksum_ok; + } + + if (jbd2_commit_block_csum_verify(journal, bh->b_data)) + goto chksum_ok; + + if (jbd2_commit_block_csum_verify_partial(journal, + bh->b_data)) { + pr_notice("JBD2: Find incomplete commit block in transaction %u block %lu\n", + next_commit_ID, next_log_block); + goto chksum_ok; + } + +chksum_error: + if (commit_time < last_trans_commit_time) + goto ignore_crc_mismatch; + info->end_transaction = next_commit_ID; + info->head_block = head_block; + + if (!jbd2_has_feature_async_commit(journal)) { + journal->j_failed_commit = next_commit_ID; + break; + } + +chksum_ok: + last_trans_commit_time = commit_time; + head_block = next_log_block; + next_commit_ID++; + continue; + + case JBD2_REVOKE_BLOCK: + /* + * If we aren't in the SCAN or REVOKE pass, then we can + * just skip over this block. + */ + if (pass != PASS_REVOKE && pass != PASS_SCAN) + continue; + + /* + * Check revoke block crc in pass_scan, if csum verify + * failed, check commit block time later. + */ + if (pass == PASS_SCAN && + !jbd2_descriptor_block_csum_verify(journal, + bh->b_data)) { + jbd2_debug(1, "JBD2: invalid revoke block found in %lu\n", + next_log_block); + need_check_commit_time = true; + } + + err = scan_revoke_records(journal, pass, bh, + next_commit_ID, info); + if (err) + goto failed; + continue; + + default: + jbd2_debug(3, "Unrecognised magic %d, end of scan.\n", + blocktype); + goto done; + } + } + + done: + brelse(bh); + /* + * We broke out of the log scan loop: either we came to the + * known end of the log or we found an unexpected block in the + * log. If the latter happened, then we know that the "current" + * transaction marks the end of the valid log. + */ + + if (pass == PASS_SCAN) { + if (!info->end_transaction) + info->end_transaction = next_commit_ID; + if (!info->head_block) + info->head_block = head_block; + } else { + /* It's really bad news if different passes end up at + * different places (but possible due to IO errors). */ + if (info->end_transaction != next_commit_ID) { + printk(KERN_ERR "JBD2: recovery pass %d ended at " + "transaction %u, expected %u\n", + pass, next_commit_ID, info->end_transaction); + if (!success) + success = -EIO; + } + } + + if (jbd2_has_feature_fast_commit(journal) && pass != PASS_REVOKE) { + err = fc_do_one_pass(journal, info, pass); + if (err) + success = err; + } + + return success; + + failed: + brelse(bh); + return err; +} + +/* Scan a revoke record, marking all blocks mentioned as revoked. */ + +static int scan_revoke_records(journal_t *journal, enum passtype pass, + struct buffer_head *bh, tid_t sequence, + struct recovery_info *info) +{ + jbd2_journal_revoke_header_t *header; + int offset, max; + unsigned csum_size = 0; + __u32 rcount; + int record_len = 4; + + header = (jbd2_journal_revoke_header_t *) bh->b_data; + offset = sizeof(jbd2_journal_revoke_header_t); + rcount = be32_to_cpu(header->r_count); + + if (jbd2_journal_has_csum_v2or3(journal)) + csum_size = sizeof(struct jbd2_journal_block_tail); + if (rcount > journal->j_blocksize - csum_size) + return -EINVAL; + max = rcount; + + if (jbd2_has_feature_64bit(journal)) + record_len = 8; + + if (pass == PASS_SCAN) { + info->nr_revokes += (max - offset) / record_len; + return 0; + } + + while (offset + record_len <= max) { + unsigned long long blocknr; + int err; + + if (record_len == 4) + blocknr = be32_to_cpu(* ((__be32 *) (bh->b_data+offset))); + else + blocknr = be64_to_cpu(* ((__be64 *) (bh->b_data+offset))); + offset += record_len; + err = jbd2_journal_set_revoke(journal, blocknr, sequence); + if (err) + return err; + } + return 0; +} -- 2.43.0