diff options
Diffstat (limited to 'fs/jbd2/journal.c')
| -rw-r--r-- | fs/jbd2/journal.c | 3029 |
1 files changed, 3029 insertions, 0 deletions
diff --git a/fs/jbd2/journal.c b/fs/jbd2/journal.c new file mode 100644 index 000000000..effd837b8 --- /dev/null +++ b/fs/jbd2/journal.c @@ -0,0 +1,3029 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * linux/fs/jbd2/journal.c + * + * Written by Stephen C. Tweedie <sct@redhat.com>, 1998 + * + * Copyright 1998 Red Hat corp --- All Rights Reserved + * + * Generic filesystem journal-writing code; part of the ext2fs + * journaling system. + * + * This file manages journals: areas of disk reserved for logging + * transactional updates. This includes the kernel journaling thread + * which is responsible for scheduling updates to the log. + * + * We do not actually manage the physical storage of the journal in this + * file: that is left to a per-journal policy function, which allows us + * to store the journal within a filesystem-specified area for ext2 + * journaling (ext2 can use a reserved inode for storing the log). + */ + +#include <linux/module.h> +#include <linux/time.h> +#include <linux/fs.h> +#include <linux/jbd2.h> +#include <linux/errno.h> +#include <linux/slab.h> +#include <linux/init.h> +#include <linux/mm.h> +#include <linux/freezer.h> +#include <linux/pagemap.h> +#include <linux/kthread.h> +#include <linux/poison.h> +#include <linux/proc_fs.h> +#include <linux/seq_file.h> +#include <linux/math64.h> +#include <linux/hash.h> +#include <linux/log2.h> +#include <linux/vmalloc.h> +#include <linux/backing-dev.h> +#include <linux/bitops.h> +#include <linux/ratelimit.h> +#include <linux/sched/mm.h> + +#define CREATE_TRACE_POINTS +#include <trace/events/jbd2.h> + +#include <linux/uaccess.h> +#include <asm/page.h> + +#ifdef CONFIG_JBD2_DEBUG +ushort jbd2_journal_enable_debug __read_mostly; +EXPORT_SYMBOL(jbd2_journal_enable_debug); + +module_param_named(jbd2_debug, jbd2_journal_enable_debug, ushort, 0644); +MODULE_PARM_DESC(jbd2_debug, "Debugging level for jbd2"); +#endif + +EXPORT_SYMBOL(jbd2_journal_extend); +EXPORT_SYMBOL(jbd2_journal_stop); +EXPORT_SYMBOL(jbd2_journal_lock_updates); +EXPORT_SYMBOL(jbd2_journal_unlock_updates); +EXPORT_SYMBOL(jbd2_journal_get_write_access); +EXPORT_SYMBOL(jbd2_journal_get_create_access); +EXPORT_SYMBOL(jbd2_journal_get_undo_access); +EXPORT_SYMBOL(jbd2_journal_set_triggers); +EXPORT_SYMBOL(jbd2_journal_dirty_metadata); +EXPORT_SYMBOL(jbd2_journal_forget); +EXPORT_SYMBOL(jbd2_journal_flush); +EXPORT_SYMBOL(jbd2_journal_revoke); + +EXPORT_SYMBOL(jbd2_journal_init_dev); +EXPORT_SYMBOL(jbd2_journal_init_inode); +EXPORT_SYMBOL(jbd2_journal_check_used_features); +EXPORT_SYMBOL(jbd2_journal_check_available_features); +EXPORT_SYMBOL(jbd2_journal_set_features); +EXPORT_SYMBOL(jbd2_journal_load); +EXPORT_SYMBOL(jbd2_journal_destroy); +EXPORT_SYMBOL(jbd2_journal_abort); +EXPORT_SYMBOL(jbd2_journal_errno); +EXPORT_SYMBOL(jbd2_journal_ack_err); +EXPORT_SYMBOL(jbd2_journal_clear_err); +EXPORT_SYMBOL(jbd2_log_wait_commit); +EXPORT_SYMBOL(jbd2_log_start_commit); +EXPORT_SYMBOL(jbd2_journal_start_commit); +EXPORT_SYMBOL(jbd2_journal_force_commit_nested); +EXPORT_SYMBOL(jbd2_journal_wipe); +EXPORT_SYMBOL(jbd2_journal_blocks_per_page); +EXPORT_SYMBOL(jbd2_journal_invalidatepage); +EXPORT_SYMBOL(jbd2_journal_try_to_free_buffers); +EXPORT_SYMBOL(jbd2_journal_force_commit); +EXPORT_SYMBOL(jbd2_journal_inode_ranged_write); +EXPORT_SYMBOL(jbd2_journal_inode_ranged_wait); +EXPORT_SYMBOL(jbd2_journal_submit_inode_data_buffers); +EXPORT_SYMBOL(jbd2_journal_finish_inode_data_buffers); +EXPORT_SYMBOL(jbd2_journal_init_jbd_inode); +EXPORT_SYMBOL(jbd2_journal_release_jbd_inode); +EXPORT_SYMBOL(jbd2_journal_begin_ordered_truncate); +EXPORT_SYMBOL(jbd2_inode_cache); + +static int jbd2_journal_create_slab(size_t slab_size); + +#ifdef CONFIG_JBD2_DEBUG +void __jbd2_debug(int level, const char *file, const char *func, + unsigned int line, const char *fmt, ...) +{ + struct va_format vaf; + va_list args; + + if (level > jbd2_journal_enable_debug) + return; + va_start(args, fmt); + vaf.fmt = fmt; + vaf.va = &args; + printk(KERN_DEBUG "%s: (%s, %u): %pV", file, func, line, &vaf); + va_end(args); +} +EXPORT_SYMBOL(__jbd2_debug); +#endif + +/* Checksumming functions */ +static int jbd2_verify_csum_type(journal_t *j, journal_superblock_t *sb) +{ + if (!jbd2_journal_has_csum_v2or3_feature(j)) + return 1; + + return sb->s_checksum_type == JBD2_CRC32C_CHKSUM; +} + +static __be32 jbd2_superblock_csum(journal_t *j, journal_superblock_t *sb) +{ + __u32 csum; + __be32 old_csum; + + old_csum = sb->s_checksum; + sb->s_checksum = 0; + csum = jbd2_chksum(j, ~0, (char *)sb, sizeof(journal_superblock_t)); + sb->s_checksum = old_csum; + + return cpu_to_be32(csum); +} + +/* + * Helper function used to manage commit timeouts + */ + +static void commit_timeout(struct timer_list *t) +{ + journal_t *journal = from_timer(journal, t, j_commit_timer); + + wake_up_process(journal->j_task); +} + +/* + * kjournald2: The main thread function used to manage a logging device + * journal. + * + * This kernel thread is responsible for two things: + * + * 1) COMMIT: Every so often we need to commit the current state of the + * filesystem to disk. The journal thread is responsible for writing + * all of the metadata buffers to disk. If a fast commit is ongoing + * journal thread waits until it's done and then continues from + * there on. + * + * 2) CHECKPOINT: We cannot reuse a used section of the log file until all + * of the data in that part of the log has been rewritten elsewhere on + * the disk. Flushing these old buffers to reclaim space in the log is + * known as checkpointing, and this thread is responsible for that job. + */ + +static int kjournald2(void *arg) +{ + journal_t *journal = arg; + transaction_t *transaction; + + /* + * Set up an interval timer which can be used to trigger a commit wakeup + * after the commit interval expires + */ + timer_setup(&journal->j_commit_timer, commit_timeout, 0); + + set_freezable(); + + /* Record that the journal thread is running */ + journal->j_task = current; + wake_up(&journal->j_wait_done_commit); + + /* + * Make sure that no allocations from this kernel thread will ever + * recurse to the fs layer because we are responsible for the + * transaction commit and any fs involvement might get stuck waiting for + * the trasn. commit. + */ + memalloc_nofs_save(); + + /* + * And now, wait forever for commit wakeup events. + */ + write_lock(&journal->j_state_lock); + +loop: + if (journal->j_flags & JBD2_UNMOUNT) + goto end_loop; + + jbd_debug(1, "commit_sequence=%u, commit_request=%u\n", + journal->j_commit_sequence, journal->j_commit_request); + + if (journal->j_commit_sequence != journal->j_commit_request) { + jbd_debug(1, "OK, requests differ\n"); + write_unlock(&journal->j_state_lock); + del_timer_sync(&journal->j_commit_timer); + jbd2_journal_commit_transaction(journal); + write_lock(&journal->j_state_lock); + goto loop; + } + + wake_up(&journal->j_wait_done_commit); + if (freezing(current)) { + /* + * The simpler the better. Flushing journal isn't a + * good idea, because that depends on threads that may + * be already stopped. + */ + jbd_debug(1, "Now suspending kjournald2\n"); + write_unlock(&journal->j_state_lock); + try_to_freeze(); + write_lock(&journal->j_state_lock); + } else { + /* + * We assume on resume that commits are already there, + * so we don't sleep + */ + DEFINE_WAIT(wait); + int should_sleep = 1; + + prepare_to_wait(&journal->j_wait_commit, &wait, + TASK_INTERRUPTIBLE); + if (journal->j_commit_sequence != journal->j_commit_request) + should_sleep = 0; + transaction = journal->j_running_transaction; + if (transaction && time_after_eq(jiffies, + transaction->t_expires)) + should_sleep = 0; + if (journal->j_flags & JBD2_UNMOUNT) + should_sleep = 0; + if (should_sleep) { + write_unlock(&journal->j_state_lock); + schedule(); + write_lock(&journal->j_state_lock); + } + finish_wait(&journal->j_wait_commit, &wait); + } + + jbd_debug(1, "kjournald2 wakes\n"); + + /* + * Were we woken up by a commit wakeup event? + */ + transaction = journal->j_running_transaction; + if (transaction && time_after_eq(jiffies, transaction->t_expires)) { + journal->j_commit_request = transaction->t_tid; + jbd_debug(1, "woke because of timeout\n"); + } + goto loop; + +end_loop: + del_timer_sync(&journal->j_commit_timer); + journal->j_task = NULL; + wake_up(&journal->j_wait_done_commit); + jbd_debug(1, "Journal thread exiting.\n"); + write_unlock(&journal->j_state_lock); + return 0; +} + +static int jbd2_journal_start_thread(journal_t *journal) +{ + struct task_struct *t; + + t = kthread_run(kjournald2, journal, "jbd2/%s", + journal->j_devname); + if (IS_ERR(t)) + return PTR_ERR(t); + + wait_event(journal->j_wait_done_commit, journal->j_task != NULL); + return 0; +} + +static void journal_kill_thread(journal_t *journal) +{ + write_lock(&journal->j_state_lock); + journal->j_flags |= JBD2_UNMOUNT; + + while (journal->j_task) { + write_unlock(&journal->j_state_lock); + wake_up(&journal->j_wait_commit); + wait_event(journal->j_wait_done_commit, journal->j_task == NULL); + write_lock(&journal->j_state_lock); + } + write_unlock(&journal->j_state_lock); +} + +/* + * jbd2_journal_write_metadata_buffer: write a metadata buffer to the journal. + * + * Writes a metadata buffer to a given disk block. The actual IO is not + * performed but a new buffer_head is constructed which labels the data + * to be written with the correct destination disk block. + * + * Any magic-number escaping which needs to be done will cause a + * copy-out here. If the buffer happens to start with the + * JBD2_MAGIC_NUMBER, then we can't write it to the log directly: the + * magic number is only written to the log for descripter blocks. In + * this case, we copy the data and replace the first word with 0, and we + * return a result code which indicates that this buffer needs to be + * marked as an escaped buffer in the corresponding log descriptor + * block. The missing word can then be restored when the block is read + * during recovery. + * + * If the source buffer has already been modified by a new transaction + * since we took the last commit snapshot, we use the frozen copy of + * that data for IO. If we end up using the existing buffer_head's data + * for the write, then we have to make sure nobody modifies it while the + * IO is in progress. do_get_write_access() handles this. + * + * The function returns a pointer to the buffer_head to be used for IO. + * + * + * Return value: + * <0: Error + * >=0: Finished OK + * + * On success: + * Bit 0 set == escape performed on the data + * Bit 1 set == buffer copy-out performed (kfree the data after IO) + */ + +int jbd2_journal_write_metadata_buffer(transaction_t *transaction, + struct journal_head *jh_in, + struct buffer_head **bh_out, + sector_t blocknr) +{ + int need_copy_out = 0; + int done_copy_out = 0; + int do_escape = 0; + char *mapped_data; + struct buffer_head *new_bh; + struct page *new_page; + unsigned int new_offset; + struct buffer_head *bh_in = jh2bh(jh_in); + journal_t *journal = transaction->t_journal; + + /* + * The buffer really shouldn't be locked: only the current committing + * transaction is allowed to write it, so nobody else is allowed + * to do any IO. + * + * akpm: except if we're journalling data, and write() output is + * also part of a shared mapping, and another thread has + * decided to launch a writepage() against this buffer. + */ + J_ASSERT_BH(bh_in, buffer_jbddirty(bh_in)); + + new_bh = alloc_buffer_head(GFP_NOFS|__GFP_NOFAIL); + + /* keep subsequent assertions sane */ + atomic_set(&new_bh->b_count, 1); + + spin_lock(&jh_in->b_state_lock); +repeat: + /* + * If a new transaction has already done a buffer copy-out, then + * we use that version of the data for the commit. + */ + if (jh_in->b_frozen_data) { + done_copy_out = 1; + new_page = virt_to_page(jh_in->b_frozen_data); + new_offset = offset_in_page(jh_in->b_frozen_data); + } else { + new_page = jh2bh(jh_in)->b_page; + new_offset = offset_in_page(jh2bh(jh_in)->b_data); + } + + mapped_data = kmap_atomic(new_page); + /* + * Fire data frozen trigger if data already wasn't frozen. Do this + * before checking for escaping, as the trigger may modify the magic + * offset. If a copy-out happens afterwards, it will have the correct + * data in the buffer. + */ + if (!done_copy_out) + jbd2_buffer_frozen_trigger(jh_in, mapped_data + new_offset, + jh_in->b_triggers); + + /* + * Check for escaping + */ + if (*((__be32 *)(mapped_data + new_offset)) == + cpu_to_be32(JBD2_MAGIC_NUMBER)) { + need_copy_out = 1; + do_escape = 1; + } + kunmap_atomic(mapped_data); + + /* + * Do we need to do a data copy? + */ + if (need_copy_out && !done_copy_out) { + char *tmp; + + spin_unlock(&jh_in->b_state_lock); + tmp = jbd2_alloc(bh_in->b_size, GFP_NOFS); + if (!tmp) { + brelse(new_bh); + return -ENOMEM; + } + spin_lock(&jh_in->b_state_lock); + if (jh_in->b_frozen_data) { + jbd2_free(tmp, bh_in->b_size); + goto repeat; + } + + jh_in->b_frozen_data = tmp; + mapped_data = kmap_atomic(new_page); + memcpy(tmp, mapped_data + new_offset, bh_in->b_size); + kunmap_atomic(mapped_data); + + new_page = virt_to_page(tmp); + new_offset = offset_in_page(tmp); + done_copy_out = 1; + + /* + * This isn't strictly necessary, as we're using frozen + * data for the escaping, but it keeps consistency with + * b_frozen_data usage. + */ + jh_in->b_frozen_triggers = jh_in->b_triggers; + } + + /* + * Did we need to do an escaping? Now we've done all the + * copying, we can finally do so. + */ + if (do_escape) { + mapped_data = kmap_atomic(new_page); + *((unsigned int *)(mapped_data + new_offset)) = 0; + kunmap_atomic(mapped_data); + } + + set_bh_page(new_bh, new_page, new_offset); + new_bh->b_size = bh_in->b_size; + new_bh->b_bdev = journal->j_dev; + new_bh->b_blocknr = blocknr; + new_bh->b_private = bh_in; + set_buffer_mapped(new_bh); + set_buffer_dirty(new_bh); + + *bh_out = new_bh; + + /* + * The to-be-written buffer needs to get moved to the io queue, + * and the original buffer whose contents we are shadowing or + * copying is moved to the transaction's shadow queue. + */ + JBUFFER_TRACE(jh_in, "file as BJ_Shadow"); + spin_lock(&journal->j_list_lock); + __jbd2_journal_file_buffer(jh_in, transaction, BJ_Shadow); + spin_unlock(&journal->j_list_lock); + set_buffer_shadow(bh_in); + spin_unlock(&jh_in->b_state_lock); + + return do_escape | (done_copy_out << 1); +} + +/* + * Allocation code for the journal file. Manage the space left in the + * journal, so that we can begin checkpointing when appropriate. + */ + +/* + * Called with j_state_lock locked for writing. + * Returns true if a transaction commit was started. + */ +int __jbd2_log_start_commit(journal_t *journal, tid_t target) +{ + /* Return if the txn has already requested to be committed */ + if (journal->j_commit_request == target) + return 0; + + /* + * The only transaction we can possibly wait upon is the + * currently running transaction (if it exists). Otherwise, + * the target tid must be an old one. + */ + if (journal->j_running_transaction && + journal->j_running_transaction->t_tid == target) { + /* + * We want a new commit: OK, mark the request and wakeup the + * commit thread. We do _not_ do the commit ourselves. + */ + + journal->j_commit_request = target; + jbd_debug(1, "JBD2: requesting commit %u/%u\n", + journal->j_commit_request, + journal->j_commit_sequence); + journal->j_running_transaction->t_requested = jiffies; + wake_up(&journal->j_wait_commit); + return 1; + } else if (!tid_geq(journal->j_commit_request, target)) + /* This should never happen, but if it does, preserve + the evidence before kjournald goes into a loop and + increments j_commit_sequence beyond all recognition. */ + WARN_ONCE(1, "JBD2: bad log_start_commit: %u %u %u %u\n", + journal->j_commit_request, + journal->j_commit_sequence, + target, journal->j_running_transaction ? + journal->j_running_transaction->t_tid : 0); + return 0; +} + +int jbd2_log_start_commit(journal_t *journal, tid_t tid) +{ + int ret; + + write_lock(&journal->j_state_lock); + ret = __jbd2_log_start_commit(journal, tid); + write_unlock(&journal->j_state_lock); + return ret; +} + +/* + * Force and wait any uncommitted transactions. We can only force the running + * transaction if we don't have an active handle, otherwise, we will deadlock. + * Returns: <0 in case of error, + * 0 if nothing to commit, + * 1 if transaction was successfully committed. + */ +static int __jbd2_journal_force_commit(journal_t *journal) +{ + transaction_t *transaction = NULL; + tid_t tid; + int need_to_start = 0, ret = 0; + + read_lock(&journal->j_state_lock); + if (journal->j_running_transaction && !current->journal_info) { + transaction = journal->j_running_transaction; + if (!tid_geq(journal->j_commit_request, transaction->t_tid)) + need_to_start = 1; + } else if (journal->j_committing_transaction) + transaction = journal->j_committing_transaction; + + if (!transaction) { + /* Nothing to commit */ + read_unlock(&journal->j_state_lock); + return 0; + } + tid = transaction->t_tid; + read_unlock(&journal->j_state_lock); + if (need_to_start) + jbd2_log_start_commit(journal, tid); + ret = jbd2_log_wait_commit(journal, tid); + if (!ret) + ret = 1; + + return ret; +} + +/** + * jbd2_journal_force_commit_nested - Force and wait upon a commit if the + * calling process is not within transaction. + * + * @journal: journal to force + * Returns true if progress was made. + * + * This is used for forcing out undo-protected data which contains + * bitmaps, when the fs is running out of space. + */ +int jbd2_journal_force_commit_nested(journal_t *journal) +{ + int ret; + + ret = __jbd2_journal_force_commit(journal); + return ret > 0; +} + +/** + * jbd2_journal_force_commit() - force any uncommitted transactions + * @journal: journal to force + * + * Caller want unconditional commit. We can only force the running transaction + * if we don't have an active handle, otherwise, we will deadlock. + */ +int jbd2_journal_force_commit(journal_t *journal) +{ + int ret; + + J_ASSERT(!current->journal_info); + ret = __jbd2_journal_force_commit(journal); + if (ret > 0) + ret = 0; + return ret; +} + +/* + * Start a commit of the current running transaction (if any). Returns true + * if a transaction is going to be committed (or is currently already + * committing), and fills its tid in at *ptid + */ +int jbd2_journal_start_commit(journal_t *journal, tid_t *ptid) +{ + int ret = 0; + + write_lock(&journal->j_state_lock); + if (journal->j_running_transaction) { + tid_t tid = journal->j_running_transaction->t_tid; + + __jbd2_log_start_commit(journal, tid); + /* There's a running transaction and we've just made sure + * it's commit has been scheduled. */ + if (ptid) + *ptid = tid; + ret = 1; + } else if (journal->j_committing_transaction) { + /* + * If commit has been started, then we have to wait for + * completion of that transaction. + */ + if (ptid) + *ptid = journal->j_committing_transaction->t_tid; + ret = 1; + } + write_unlock(&journal->j_state_lock); + return ret; +} + +/* + * Return 1 if a given transaction has not yet sent barrier request + * connected with a transaction commit. If 0 is returned, transaction + * may or may not have sent the barrier. Used to avoid sending barrier + * twice in common cases. + */ +int jbd2_trans_will_send_data_barrier(journal_t *journal, tid_t tid) +{ + int ret = 0; + transaction_t *commit_trans; + + if (!(journal->j_flags & JBD2_BARRIER)) + return 0; + read_lock(&journal->j_state_lock); + /* Transaction already committed? */ + if (tid_geq(journal->j_commit_sequence, tid)) + goto out; + commit_trans = journal->j_committing_transaction; + if (!commit_trans || commit_trans->t_tid != tid) { + ret = 1; + goto out; + } + /* + * Transaction is being committed and we already proceeded to + * submitting a flush to fs partition? + */ + if (journal->j_fs_dev != journal->j_dev) { + if (!commit_trans->t_need_data_flush || + commit_trans->t_state >= T_COMMIT_DFLUSH) + goto out; + } else { + if (commit_trans->t_state >= T_COMMIT_JFLUSH) + goto out; + } + ret = 1; +out: + read_unlock(&journal->j_state_lock); + return ret; +} +EXPORT_SYMBOL(jbd2_trans_will_send_data_barrier); + +/* + * Wait for a specified commit to complete. + * The caller may not hold the journal lock. + */ +int jbd2_log_wait_commit(journal_t *journal, tid_t tid) +{ + int err = 0; + + read_lock(&journal->j_state_lock); +#ifdef CONFIG_PROVE_LOCKING + /* + * Some callers make sure transaction is already committing and in that + * case we cannot block on open handles anymore. So don't warn in that + * case. + */ + if (tid_gt(tid, journal->j_commit_sequence) && + (!journal->j_committing_transaction || + journal->j_committing_transaction->t_tid != tid)) { + read_unlock(&journal->j_state_lock); + jbd2_might_wait_for_commit(journal); + read_lock(&journal->j_state_lock); + } +#endif +#ifdef CONFIG_JBD2_DEBUG + if (!tid_geq(journal->j_commit_request, tid)) { + printk(KERN_ERR + "%s: error: j_commit_request=%u, tid=%u\n", + __func__, journal->j_commit_request, tid); + } +#endif + while (tid_gt(tid, journal->j_commit_sequence)) { + jbd_debug(1, "JBD2: want %u, j_commit_sequence=%u\n", + tid, journal->j_commit_sequence); + read_unlock(&journal->j_state_lock); + wake_up(&journal->j_wait_commit); + wait_event(journal->j_wait_done_commit, + !tid_gt(tid, journal->j_commit_sequence)); + read_lock(&journal->j_state_lock); + } + read_unlock(&journal->j_state_lock); + + if (unlikely(is_journal_aborted(journal))) + err = -EIO; + return err; +} + +/* + * Start a fast commit. If there's an ongoing fast or full commit wait for + * it to complete. Returns 0 if a new fast commit was started. Returns -EALREADY + * if a fast commit is not needed, either because there's an already a commit + * going on or this tid has already been committed. Returns -EINVAL if no jbd2 + * commit has yet been performed. + */ +int jbd2_fc_begin_commit(journal_t *journal, tid_t tid) +{ + if (unlikely(is_journal_aborted(journal))) + return -EIO; + /* + * Fast commits only allowed if at least one full commit has + * been processed. + */ + if (!journal->j_stats.ts_tid) + return -EINVAL; + + write_lock(&journal->j_state_lock); + if (tid <= journal->j_commit_sequence) { + write_unlock(&journal->j_state_lock); + return -EALREADY; + } + + if (journal->j_flags & JBD2_FULL_COMMIT_ONGOING || + (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(); + finish_wait(&journal->j_fc_wait, &wait); + return -EALREADY; + } + journal->j_flags |= JBD2_FAST_COMMIT_ONGOING; + write_unlock(&journal->j_state_lock); + jbd2_journal_lock_updates(journal); + + return 0; +} +EXPORT_SYMBOL(jbd2_fc_begin_commit); + +/* + * Stop a fast commit. If fallback is set, this function starts commit of + * TID tid before any other fast commit can start. + */ +static int __jbd2_fc_end_commit(journal_t *journal, tid_t tid, bool fallback) +{ + jbd2_journal_unlock_updates(journal); + if (journal->j_fc_cleanup_callback) + journal->j_fc_cleanup_callback(journal, 0); + write_lock(&journal->j_state_lock); + journal->j_flags &= ~JBD2_FAST_COMMIT_ONGOING; + if (fallback) + journal->j_flags |= JBD2_FULL_COMMIT_ONGOING; + write_unlock(&journal->j_state_lock); + wake_up(&journal->j_fc_wait); + if (fallback) + return jbd2_complete_transaction(journal, tid); + return 0; +} + +int jbd2_fc_end_commit(journal_t *journal) +{ + return __jbd2_fc_end_commit(journal, 0, false); +} +EXPORT_SYMBOL(jbd2_fc_end_commit); + +int jbd2_fc_end_commit_fallback(journal_t *journal) +{ + tid_t tid; + + read_lock(&journal->j_state_lock); + tid = journal->j_running_transaction ? + journal->j_running_transaction->t_tid : 0; + read_unlock(&journal->j_state_lock); + return __jbd2_fc_end_commit(journal, tid, true); +} +EXPORT_SYMBOL(jbd2_fc_end_commit_fallback); + +/* Return 1 when transaction with given tid has already committed. */ +int jbd2_transaction_committed(journal_t *journal, tid_t tid) +{ + int ret = 1; + + read_lock(&journal->j_state_lock); + if (journal->j_running_transaction && + journal->j_running_transaction->t_tid == tid) + ret = 0; + if (journal->j_committing_transaction && + journal->j_committing_transaction->t_tid == tid) + ret = 0; + read_unlock(&journal->j_state_lock); + return ret; +} +EXPORT_SYMBOL(jbd2_transaction_committed); + +/* + * When this function returns the transaction corresponding to tid + * will be completed. If the transaction has currently running, start + * committing that transaction before waiting for it to complete. If + * the transaction id is stale, it is by definition already completed, + * so just return SUCCESS. + */ +int jbd2_complete_transaction(journal_t *journal, tid_t tid) +{ + int need_to_wait = 1; + + read_lock(&journal->j_state_lock); + if (journal->j_running_transaction && + journal->j_running_transaction->t_tid == tid) { + if (journal->j_commit_request != tid) { + /* transaction not yet started, so request it */ + read_unlock(&journal->j_state_lock); + jbd2_log_start_commit(journal, tid); + goto wait_commit; + } + } else if (!(journal->j_committing_transaction && + journal->j_committing_transaction->t_tid == tid)) + need_to_wait = 0; + read_unlock(&journal->j_state_lock); + if (!need_to_wait) + return 0; +wait_commit: + return jbd2_log_wait_commit(journal, tid); +} +EXPORT_SYMBOL(jbd2_complete_transaction); + +/* + * Log buffer allocation routines: + */ + +int jbd2_journal_next_log_block(journal_t *journal, unsigned long long *retp) +{ + unsigned long blocknr; + + write_lock(&journal->j_state_lock); + J_ASSERT(journal->j_free > 1); + + blocknr = journal->j_head; + journal->j_head++; + journal->j_free--; + if (journal->j_head == journal->j_last) + journal->j_head = journal->j_first; + write_unlock(&journal->j_state_lock); + return jbd2_journal_bmap(journal, blocknr, retp); +} + +/* Map one fast commit buffer for use by the file system */ +int jbd2_fc_get_buf(journal_t *journal, struct buffer_head **bh_out) +{ + unsigned long long pblock; + unsigned long blocknr; + int ret = 0; + struct buffer_head *bh; + int fc_off; + + *bh_out = NULL; + + if (journal->j_fc_off + journal->j_fc_first < journal->j_fc_last) { + fc_off = journal->j_fc_off; + blocknr = journal->j_fc_first + fc_off; + journal->j_fc_off++; + } else { + ret = -EINVAL; + } + + if (ret) + return ret; + + ret = jbd2_journal_bmap(journal, blocknr, &pblock); + if (ret) + return ret; + + bh = __getblk(journal->j_dev, pblock, journal->j_blocksize); + if (!bh) + return -ENOMEM; + + + journal->j_fc_wbuf[fc_off] = bh; + + *bh_out = bh; + + return 0; +} +EXPORT_SYMBOL(jbd2_fc_get_buf); + +/* + * Wait on fast commit buffers that were allocated by jbd2_fc_get_buf + * for completion. + */ +int jbd2_fc_wait_bufs(journal_t *journal, int num_blks) +{ + struct buffer_head *bh; + int i, j_fc_off; + + j_fc_off = journal->j_fc_off; + + /* + * Wait in reverse order to minimize chances of us being woken up before + * all IOs have completed + */ + for (i = j_fc_off - 1; i >= j_fc_off - num_blks; i--) { + bh = journal->j_fc_wbuf[i]; + wait_on_buffer(bh); + /* + * Update j_fc_off so jbd2_fc_release_bufs can release remain + * buffer head. + */ + if (unlikely(!buffer_uptodate(bh))) { + journal->j_fc_off = i + 1; + return -EIO; + } + put_bh(bh); + journal->j_fc_wbuf[i] = NULL; + } + + return 0; +} +EXPORT_SYMBOL(jbd2_fc_wait_bufs); + +/* + * Wait on fast commit buffers that were allocated by jbd2_fc_get_buf + * for completion. + */ +int jbd2_fc_release_bufs(journal_t *journal) +{ + struct buffer_head *bh; + int i, j_fc_off; + + j_fc_off = journal->j_fc_off; + + /* + * Wait in reverse order to minimize chances of us being woken up before + * all IOs have completed + */ + for (i = j_fc_off - 1; i >= 0; i--) { + bh = journal->j_fc_wbuf[i]; + if (!bh) + break; + put_bh(bh); + journal->j_fc_wbuf[i] = NULL; + } + + return 0; +} +EXPORT_SYMBOL(jbd2_fc_release_bufs); + +/* + * Conversion of logical to physical block numbers for the journal + * + * On external journals the journal blocks are identity-mapped, so + * this is a no-op. If needed, we can use j_blk_offset - everything is + * ready. + */ +int jbd2_journal_bmap(journal_t *journal, unsigned long blocknr, + unsigned long long *retp) +{ + int err = 0; + unsigned long long ret; + sector_t block = 0; + + if (journal->j_inode) { + block = blocknr; + ret = bmap(journal->j_inode, &block); + + if (ret || !block) { + printk(KERN_ALERT "%s: journal block not found " + "at offset %lu on %s\n", + __func__, blocknr, journal->j_devname); + err = -EIO; + jbd2_journal_abort(journal, err); + } else { + *retp = block; + } + + } else { + *retp = blocknr; /* +journal->j_blk_offset */ + } + return err; +} + +/* + * We play buffer_head aliasing tricks to write data/metadata blocks to + * the journal without copying their contents, but for journal + * descriptor blocks we do need to generate bona fide buffers. + * + * After the caller of jbd2_journal_get_descriptor_buffer() has finished modifying + * the buffer's contents they really should run flush_dcache_page(bh->b_page). + * But we don't bother doing that, so there will be coherency problems with + * mmaps of blockdevs which hold live JBD-controlled filesystems. + */ +struct buffer_head * +jbd2_journal_get_descriptor_buffer(transaction_t *transaction, int type) +{ + journal_t *journal = transaction->t_journal; + struct buffer_head *bh; + unsigned long long blocknr; + journal_header_t *header; + int err; + + err = jbd2_journal_next_log_block(journal, &blocknr); + + if (err) + return NULL; + + bh = __getblk(journal->j_dev, blocknr, journal->j_blocksize); + if (!bh) + return NULL; + atomic_dec(&transaction->t_outstanding_credits); + lock_buffer(bh); + memset(bh->b_data, 0, journal->j_blocksize); + header = (journal_header_t *)bh->b_data; + header->h_magic = cpu_to_be32(JBD2_MAGIC_NUMBER); + header->h_blocktype = cpu_to_be32(type); + header->h_sequence = cpu_to_be32(transaction->t_tid); + set_buffer_uptodate(bh); + unlock_buffer(bh); + BUFFER_TRACE(bh, "return this buffer"); + return bh; +} + +void jbd2_descriptor_block_csum_set(journal_t *j, struct buffer_head *bh) +{ + struct jbd2_journal_block_tail *tail; + __u32 csum; + + if (!jbd2_journal_has_csum_v2or3(j)) + return; + + tail = (struct jbd2_journal_block_tail *)(bh->b_data + j->j_blocksize - + sizeof(struct jbd2_journal_block_tail)); + tail->t_checksum = 0; + csum = jbd2_chksum(j, j->j_csum_seed, bh->b_data, j->j_blocksize); + tail->t_checksum = cpu_to_be32(csum); +} + +/* + * Return tid of the oldest transaction in the journal and block in the journal + * where the transaction starts. + * + * If the journal is now empty, return which will be the next transaction ID + * we will write and where will that transaction start. + * + * The return value is 0 if journal tail cannot be pushed any further, 1 if + * it can. + */ +int jbd2_journal_get_log_tail(journal_t *journal, tid_t *tid, + unsigned long *block) +{ + transaction_t *transaction; + int ret; + + read_lock(&journal->j_state_lock); + spin_lock(&journal->j_list_lock); + transaction = journal->j_checkpoint_transactions; + if (transaction) { + *tid = transaction->t_tid; + *block = transaction->t_log_start; + } else if ((transaction = journal->j_committing_transaction) != NULL) { + *tid = transaction->t_tid; + *block = transaction->t_log_start; + } else if ((transaction = journal->j_running_transaction) != NULL) { + *tid = transaction->t_tid; + *block = journal->j_head; + } else { + *tid = journal->j_transaction_sequence; + *block = journal->j_head; + } + ret = tid_gt(*tid, journal->j_tail_sequence); + spin_unlock(&journal->j_list_lock); + read_unlock(&journal->j_state_lock); + + return ret; +} + +/* + * Update information in journal structure and in on disk journal superblock + * about log tail. This function does not check whether information passed in + * really pushes log tail further. It's responsibility of the caller to make + * sure provided log tail information is valid (e.g. by holding + * j_checkpoint_mutex all the time between computing log tail and calling this + * function as is the case with jbd2_cleanup_journal_tail()). + * + * Requires j_checkpoint_mutex + */ +int __jbd2_update_log_tail(journal_t *journal, tid_t tid, unsigned long block) +{ + unsigned long freed; + int ret; + + BUG_ON(!mutex_is_locked(&journal->j_checkpoint_mutex)); + + /* + * We cannot afford for write to remain in drive's caches since as + * soon as we update j_tail, next transaction can start reusing journal + * space and if we lose sb update during power failure we'd replay + * old transaction with possibly newly overwritten data. + */ + ret = jbd2_journal_update_sb_log_tail(journal, tid, block, + REQ_SYNC | REQ_FUA); + if (ret) + goto out; + + write_lock(&journal->j_state_lock); + freed = block - journal->j_tail; + if (block < journal->j_tail) + freed += journal->j_last - journal->j_first; + + trace_jbd2_update_log_tail(journal, tid, block, freed); + jbd_debug(1, + "Cleaning journal tail from %u to %u (offset %lu), " + "freeing %lu\n", + journal->j_tail_sequence, tid, block, freed); + + journal->j_free += freed; + journal->j_tail_sequence = tid; + journal->j_tail = block; + write_unlock(&journal->j_state_lock); + +out: + return ret; +} + +/* + * This is a variation of __jbd2_update_log_tail which checks for validity of + * provided log tail and locks j_checkpoint_mutex. So it is safe against races + * with other threads updating log tail. + */ +void jbd2_update_log_tail(journal_t *journal, tid_t tid, unsigned long block) +{ + mutex_lock_io(&journal->j_checkpoint_mutex); + if (tid_gt(tid, journal->j_tail_sequence)) + __jbd2_update_log_tail(journal, tid, block); + mutex_unlock(&journal->j_checkpoint_mutex); +} + +struct jbd2_stats_proc_session { + journal_t *journal; + struct transaction_stats_s *stats; + int start; + int max; +}; + +static void *jbd2_seq_info_start(struct seq_file *seq, loff_t *pos) +{ + return *pos ? NULL : SEQ_START_TOKEN; +} + +static void *jbd2_seq_info_next(struct seq_file *seq, void *v, loff_t *pos) +{ + (*pos)++; + return NULL; +} + +static int jbd2_seq_info_show(struct seq_file *seq, void *v) +{ + struct jbd2_stats_proc_session *s = seq->private; + + if (v != SEQ_START_TOKEN) + return 0; + seq_printf(seq, "%lu transactions (%lu requested), " + "each up to %u blocks\n", + s->stats->ts_tid, s->stats->ts_requested, + s->journal->j_max_transaction_buffers); + if (s->stats->ts_tid == 0) + return 0; + seq_printf(seq, "average: \n %ums waiting for transaction\n", + jiffies_to_msecs(s->stats->run.rs_wait / s->stats->ts_tid)); + seq_printf(seq, " %ums request delay\n", + (s->stats->ts_requested == 0) ? 0 : + jiffies_to_msecs(s->stats->run.rs_request_delay / + s->stats->ts_requested)); + seq_printf(seq, " %ums running transaction\n", + jiffies_to_msecs(s->stats->run.rs_running / s->stats->ts_tid)); + seq_printf(seq, " %ums transaction was being locked\n", + jiffies_to_msecs(s->stats->run.rs_locked / s->stats->ts_tid)); + seq_printf(seq, " %ums flushing data (in ordered mode)\n", + jiffies_to_msecs(s->stats->run.rs_flushing / s->stats->ts_tid)); + seq_printf(seq, " %ums logging transaction\n", + jiffies_to_msecs(s->stats->run.rs_logging / s->stats->ts_tid)); + seq_printf(seq, " %lluus average transaction commit time\n", + div_u64(s->journal->j_average_commit_time, 1000)); + seq_printf(seq, " %lu handles per transaction\n", + s->stats->run.rs_handle_count / s->stats->ts_tid); + seq_printf(seq, " %lu blocks per transaction\n", + s->stats->run.rs_blocks / s->stats->ts_tid); + seq_printf(seq, " %lu logged blocks per transaction\n", + s->stats->run.rs_blocks_logged / s->stats->ts_tid); + return 0; +} + +static void jbd2_seq_info_stop(struct seq_file *seq, void *v) +{ +} + +static const struct seq_operations jbd2_seq_info_ops = { + .start = jbd2_seq_info_start, + .next = jbd2_seq_info_next, + .stop = jbd2_seq_info_stop, + .show = jbd2_seq_info_show, +}; + +static int jbd2_seq_info_open(struct inode *inode, struct file *file) +{ + journal_t *journal = PDE_DATA(inode); + struct jbd2_stats_proc_session *s; + int rc, size; + + s = kmalloc(sizeof(*s), GFP_KERNEL); + if (s == NULL) + return -ENOMEM; + size = sizeof(struct transaction_stats_s); + s->stats = kmalloc(size, GFP_KERNEL); + if (s->stats == NULL) { + kfree(s); + return -ENOMEM; + } + spin_lock(&journal->j_history_lock); + memcpy(s->stats, &journal->j_stats, size); + s->journal = journal; + spin_unlock(&journal->j_history_lock); + + rc = seq_open(file, &jbd2_seq_info_ops); + if (rc == 0) { + struct seq_file *m = file->private_data; + m->private = s; + } else { + kfree(s->stats); + kfree(s); + } + return rc; + +} + +static int jbd2_seq_info_release(struct inode *inode, struct file *file) +{ + struct seq_file *seq = file->private_data; + struct jbd2_stats_proc_session *s = seq->private; + kfree(s->stats); + kfree(s); + return seq_release(inode, file); +} + +static const struct proc_ops jbd2_info_proc_ops = { + .proc_open = jbd2_seq_info_open, + .proc_read = seq_read, + .proc_lseek = seq_lseek, + .proc_release = jbd2_seq_info_release, +}; + +static struct proc_dir_entry *proc_jbd2_stats; + +static void jbd2_stats_proc_init(journal_t *journal) +{ + journal->j_proc_entry = proc_mkdir(journal->j_devname, proc_jbd2_stats); + if (journal->j_proc_entry) { + proc_create_data("info", S_IRUGO, journal->j_proc_entry, + &jbd2_info_proc_ops, journal); + } +} + +static void jbd2_stats_proc_exit(journal_t *journal) +{ + remove_proc_entry("info", journal->j_proc_entry); + remove_proc_entry(journal->j_devname, proc_jbd2_stats); +} + +/* Minimum size of descriptor tag */ +static int jbd2_min_tag_size(void) +{ + /* + * Tag with 32-bit block numbers does not use last four bytes of the + * structure + */ + return sizeof(journal_block_tag_t) - 4; +} + +/* + * Management for journal control blocks: functions to create and + * destroy journal_t structures, and to initialise and read existing + * journal blocks from disk. */ + +/* First: create and setup a journal_t object in memory. We initialise + * very few fields yet: that has to wait until we have created the + * journal structures from from scratch, or loaded them from disk. */ + +static journal_t *journal_init_common(struct block_device *bdev, + struct block_device *fs_dev, + unsigned long long start, int len, int blocksize) +{ + static struct lock_class_key jbd2_trans_commit_key; + journal_t *journal; + int err; + struct buffer_head *bh; + int n; + + journal = kzalloc(sizeof(*journal), GFP_KERNEL); + if (!journal) + return NULL; + + init_waitqueue_head(&journal->j_wait_transaction_locked); + init_waitqueue_head(&journal->j_wait_done_commit); + init_waitqueue_head(&journal->j_wait_commit); + init_waitqueue_head(&journal->j_wait_updates); + init_waitqueue_head(&journal->j_wait_reserved); + init_waitqueue_head(&journal->j_fc_wait); + mutex_init(&journal->j_abort_mutex); + mutex_init(&journal->j_barrier); + mutex_init(&journal->j_checkpoint_mutex); + spin_lock_init(&journal->j_revoke_lock); + spin_lock_init(&journal->j_list_lock); + rwlock_init(&journal->j_state_lock); + + journal->j_commit_interval = (HZ * JBD2_DEFAULT_MAX_COMMIT_AGE); + journal->j_min_batch_time = 0; + journal->j_max_batch_time = 15000; /* 15ms */ + atomic_set(&journal->j_reserved_credits, 0); + + /* The journal is marked for error until we succeed with recovery! */ + journal->j_flags = JBD2_ABORT; + + /* Set up a default-sized revoke table for the new mount. */ + err = jbd2_journal_init_revoke(journal, JOURNAL_REVOKE_DEFAULT_HASH); + if (err) + goto err_cleanup; + + spin_lock_init(&journal->j_history_lock); + + lockdep_init_map(&journal->j_trans_commit_map, "jbd2_handle", + &jbd2_trans_commit_key, 0); + + /* journal descriptor can store up to n blocks -bzzz */ + journal->j_blocksize = blocksize; + journal->j_dev = bdev; + journal->j_fs_dev = fs_dev; + journal->j_blk_offset = start; + journal->j_total_len = len; + /* We need enough buffers to write out full descriptor block. */ + n = journal->j_blocksize / jbd2_min_tag_size(); + journal->j_wbufsize = n; + journal->j_fc_wbuf = NULL; + journal->j_wbuf = kmalloc_array(n, sizeof(struct buffer_head *), + GFP_KERNEL); + if (!journal->j_wbuf) + goto err_cleanup; + + bh = getblk_unmovable(journal->j_dev, start, journal->j_blocksize); + if (!bh) { + pr_err("%s: Cannot get buffer for journal superblock\n", + __func__); + goto err_cleanup; + } + journal->j_sb_buffer = bh; + journal->j_superblock = (journal_superblock_t *)bh->b_data; + + return journal; + +err_cleanup: + kfree(journal->j_wbuf); + jbd2_journal_destroy_revoke(journal); + kfree(journal); + return NULL; +} + +/* jbd2_journal_init_dev and jbd2_journal_init_inode: + * + * Create a journal structure assigned some fixed set of disk blocks to + * the journal. We don't actually touch those disk blocks yet, but we + * need to set up all of the mapping information to tell the journaling + * system where the journal blocks are. + * + */ + +/** + * journal_t * jbd2_journal_init_dev() - creates and initialises a journal structure + * @bdev: Block device on which to create the journal + * @fs_dev: Device which hold journalled filesystem for this journal. + * @start: Block nr Start of journal. + * @len: Length of the journal in blocks. + * @blocksize: blocksize of journalling device + * + * Returns: a newly created journal_t * + * + * jbd2_journal_init_dev creates a journal which maps a fixed contiguous + * range of blocks on an arbitrary block device. + * + */ +journal_t *jbd2_journal_init_dev(struct block_device *bdev, + struct block_device *fs_dev, + unsigned long long start, int len, int blocksize) +{ + journal_t *journal; + + journal = journal_init_common(bdev, fs_dev, start, len, blocksize); + if (!journal) + return NULL; + + bdevname(journal->j_dev, journal->j_devname); + strreplace(journal->j_devname, '/', '!'); + jbd2_stats_proc_init(journal); + + return journal; +} + +/** + * journal_t * jbd2_journal_init_inode () - creates a journal which maps to a inode. + * @inode: An inode to create the journal in + * + * jbd2_journal_init_inode creates a journal which maps an on-disk inode as + * the journal. The inode must exist already, must support bmap() and + * must have all data blocks preallocated. + */ +journal_t *jbd2_journal_init_inode(struct inode *inode) +{ + journal_t *journal; + sector_t blocknr; + char *p; + int err = 0; + + blocknr = 0; + err = bmap(inode, &blocknr); + + if (err || !blocknr) { + pr_err("%s: Cannot locate journal superblock\n", + __func__); + return NULL; + } + + jbd_debug(1, "JBD2: inode %s/%ld, size %lld, bits %d, blksize %ld\n", + inode->i_sb->s_id, inode->i_ino, (long long) inode->i_size, + inode->i_sb->s_blocksize_bits, inode->i_sb->s_blocksize); + + journal = journal_init_common(inode->i_sb->s_bdev, inode->i_sb->s_bdev, + blocknr, inode->i_size >> inode->i_sb->s_blocksize_bits, + inode->i_sb->s_blocksize); + if (!journal) + return NULL; + + journal->j_inode = inode; + bdevname(journal->j_dev, journal->j_devname); + p = strreplace(journal->j_devname, '/', '!'); + sprintf(p, "-%lu", journal->j_inode->i_ino); + jbd2_stats_proc_init(journal); + + return journal; +} + +/* + * If the journal init or create aborts, we need to mark the journal + * superblock as being NULL to prevent the journal destroy from writing + * back a bogus superblock. + */ +static void journal_fail_superblock(journal_t *journal) +{ + struct buffer_head *bh = journal->j_sb_buffer; + brelse(bh); + journal->j_sb_buffer = NULL; +} + +/* + * Given a journal_t structure, initialise the various fields for + * startup of a new journaling session. We use this both when creating + * a journal, and after recovering an old journal to reset it for + * subsequent use. + */ + +static int journal_reset(journal_t *journal) +{ + journal_superblock_t *sb = journal->j_superblock; + unsigned long long first, last; + + first = be32_to_cpu(sb->s_first); + last = be32_to_cpu(sb->s_maxlen); + if (first + JBD2_MIN_JOURNAL_BLOCKS > last + 1) { + printk(KERN_ERR "JBD2: Journal too short (blocks %llu-%llu).\n", + first, last); + journal_fail_superblock(journal); + return -EINVAL; + } + + journal->j_first = first; + journal->j_last = last; + + journal->j_head = journal->j_first; + journal->j_tail = journal->j_first; + journal->j_free = journal->j_last - journal->j_first; + + journal->j_tail_sequence = journal->j_transaction_sequence; + journal->j_commit_sequence = journal->j_transaction_sequence - 1; + journal->j_commit_request = journal->j_commit_sequence; + + journal->j_max_transaction_buffers = jbd2_journal_get_max_txn_bufs(journal); + + /* + * Now that journal recovery is done, turn fast commits off here. This + * way, if fast commit was enabled before the crash but if now FS has + * disabled it, we don't enable fast commits. + */ + jbd2_clear_feature_fast_commit(journal); + + /* + * As a special case, if the on-disk copy is already marked as needing + * no recovery (s_start == 0), then we can safely defer the superblock + * update until the next commit by setting JBD2_FLUSHED. This avoids + * attempting a write to a potential-readonly device. + */ + if (sb->s_start == 0) { + jbd_debug(1, "JBD2: Skipping superblock update on recovered sb " + "(start %ld, seq %u, errno %d)\n", + journal->j_tail, journal->j_tail_sequence, + journal->j_errno); + journal->j_flags |= JBD2_FLUSHED; + } else { + /* Lock here to make assertions happy... */ + mutex_lock_io(&journal->j_checkpoint_mutex); + /* + * Update log tail information. We use REQ_FUA since new + * transaction will start reusing journal space and so we + * must make sure information about current log tail is on + * disk before that. + */ + jbd2_journal_update_sb_log_tail(journal, + journal->j_tail_sequence, + journal->j_tail, + REQ_SYNC | REQ_FUA); + mutex_unlock(&journal->j_checkpoint_mutex); + } + return jbd2_journal_start_thread(journal); +} + +/* + * This function expects that the caller will have locked the journal + * buffer head, and will return with it unlocked + */ +static int jbd2_write_superblock(journal_t *journal, int write_flags) +{ + struct buffer_head *bh = journal->j_sb_buffer; + journal_superblock_t *sb = journal->j_superblock; + int ret; + + /* Buffer got discarded which means block device got invalidated */ + if (!buffer_mapped(bh)) { + unlock_buffer(bh); + return -EIO; + } + + if (!(journal->j_flags & JBD2_BARRIER)) + write_flags &= ~(REQ_FUA | REQ_PREFLUSH); + + trace_jbd2_write_superblock(journal, write_flags); + + if (buffer_write_io_error(bh)) { + /* + * Oh, dear. A previous attempt to write the journal + * superblock failed. This could happen because the + * USB device was yanked out. Or it could happen to + * be a transient write error and maybe the block will + * be remapped. Nothing we can do but to retry the + * write and hope for the best. + */ + printk(KERN_ERR "JBD2: previous I/O error detected " + "for journal superblock update for %s.\n", + journal->j_devname); + clear_buffer_write_io_error(bh); + set_buffer_uptodate(bh); + } + if (jbd2_journal_has_csum_v2or3(journal)) + sb->s_checksum = jbd2_superblock_csum(journal, sb); + get_bh(bh); + bh->b_end_io = end_buffer_write_sync; + ret = submit_bh(REQ_OP_WRITE, write_flags, bh); + wait_on_buffer(bh); + if (buffer_write_io_error(bh)) { + clear_buffer_write_io_error(bh); + set_buffer_uptodate(bh); + ret = -EIO; + } + if (ret) { + printk(KERN_ERR "JBD2: Error %d detected when updating " + "journal superblock for %s.\n", ret, + journal->j_devname); + if (!is_journal_aborted(journal)) + jbd2_journal_abort(journal, ret); + } + + return ret; +} + +/** + * jbd2_journal_update_sb_log_tail() - Update log tail in journal sb on disk. + * @journal: The journal to update. + * @tail_tid: TID of the new transaction at the tail of the log + * @tail_block: The first block of the transaction at the tail of the log + * @write_op: With which operation should we write the journal sb + * + * Update a journal's superblock information about log tail and write it to + * disk, waiting for the IO to complete. + */ +int jbd2_journal_update_sb_log_tail(journal_t *journal, tid_t tail_tid, + unsigned long tail_block, int write_op) +{ + journal_superblock_t *sb = journal->j_superblock; + int ret; + + if (is_journal_aborted(journal)) + return -EIO; + + BUG_ON(!mutex_is_locked(&journal->j_checkpoint_mutex)); + jbd_debug(1, "JBD2: updating superblock (start %lu, seq %u)\n", + tail_block, tail_tid); + + lock_buffer(journal->j_sb_buffer); + sb->s_sequence = cpu_to_be32(tail_tid); + sb->s_start = cpu_to_be32(tail_block); + + ret = jbd2_write_superblock(journal, write_op); + if (ret) + goto out; + + /* Log is no longer empty */ + write_lock(&journal->j_state_lock); + WARN_ON(!sb->s_sequence); + journal->j_flags &= ~JBD2_FLUSHED; + write_unlock(&journal->j_state_lock); + +out: + return ret; +} + +/** + * jbd2_mark_journal_empty() - Mark on disk journal as empty. + * @journal: The journal to update. + * @write_op: With which operation should we write the journal sb + * + * Update a journal's dynamic superblock fields to show that journal is empty. + * Write updated superblock to disk waiting for IO to complete. + */ +static void jbd2_mark_journal_empty(journal_t *journal, int write_op) +{ + journal_superblock_t *sb = journal->j_superblock; + bool had_fast_commit = false; + + BUG_ON(!mutex_is_locked(&journal->j_checkpoint_mutex)); + lock_buffer(journal->j_sb_buffer); + if (sb->s_start == 0) { /* Is it already empty? */ + unlock_buffer(journal->j_sb_buffer); + return; + } + + jbd_debug(1, "JBD2: Marking journal as empty (seq %u)\n", + journal->j_tail_sequence); + + sb->s_sequence = cpu_to_be32(journal->j_tail_sequence); + sb->s_start = cpu_to_be32(0); + if (jbd2_has_feature_fast_commit(journal)) { + /* + * When journal is clean, no need to commit fast commit flag and + * make file system incompatible with older kernels. + */ + jbd2_clear_feature_fast_commit(journal); + had_fast_commit = true; + } + + jbd2_write_superblock(journal, write_op); + + if (had_fast_commit) + jbd2_set_feature_fast_commit(journal); + + /* Log is no longer empty */ + write_lock(&journal->j_state_lock); + journal->j_flags |= JBD2_FLUSHED; + write_unlock(&journal->j_state_lock); +} + + +/** + * jbd2_journal_update_sb_errno() - Update error in the journal. + * @journal: The journal to update. + * + * Update a journal's errno. Write updated superblock to disk waiting for IO + * to complete. + */ +void jbd2_journal_update_sb_errno(journal_t *journal) +{ + journal_superblock_t *sb = journal->j_superblock; + int errcode; + + lock_buffer(journal->j_sb_buffer); + errcode = journal->j_errno; + if (errcode == -ESHUTDOWN) + errcode = 0; + jbd_debug(1, "JBD2: updating superblock error (errno %d)\n", errcode); + sb->s_errno = cpu_to_be32(errcode); + + jbd2_write_superblock(journal, REQ_SYNC | REQ_FUA); +} +EXPORT_SYMBOL(jbd2_journal_update_sb_errno); + +static int journal_revoke_records_per_block(journal_t *journal) +{ + int record_size; + int space = journal->j_blocksize - sizeof(jbd2_journal_revoke_header_t); + + if (jbd2_has_feature_64bit(journal)) + record_size = 8; + else + record_size = 4; + + if (jbd2_journal_has_csum_v2or3(journal)) + space -= sizeof(struct jbd2_journal_block_tail); + return space / record_size; +} + +/* + * Read the superblock for a given journal, performing initial + * validation of the format. + */ +static int journal_get_superblock(journal_t *journal) +{ + struct buffer_head *bh; + journal_superblock_t *sb; + int err = -EIO; + + bh = journal->j_sb_buffer; + + J_ASSERT(bh != NULL); + if (!buffer_uptodate(bh)) { + ll_rw_block(REQ_OP_READ, 0, 1, &bh); + wait_on_buffer(bh); + if (!buffer_uptodate(bh)) { + printk(KERN_ERR + "JBD2: IO error reading journal superblock\n"); + goto out; + } + } + + if (buffer_verified(bh)) + return 0; + + sb = journal->j_superblock; + + err = -EINVAL; + + if (sb->s_header.h_magic != cpu_to_be32(JBD2_MAGIC_NUMBER) || + sb->s_blocksize != cpu_to_be32(journal->j_blocksize)) { + printk(KERN_WARNING "JBD2: no valid journal superblock found\n"); + goto out; + } + + switch(be32_to_cpu(sb->s_header.h_blocktype)) { + case JBD2_SUPERBLOCK_V1: + journal->j_format_version = 1; + break; + case JBD2_SUPERBLOCK_V2: + journal->j_format_version = 2; + break; + default: + printk(KERN_WARNING "JBD2: unrecognised superblock format ID\n"); + goto out; + } + + if (be32_to_cpu(sb->s_maxlen) < journal->j_total_len) + journal->j_total_len = be32_to_cpu(sb->s_maxlen); + else if (be32_to_cpu(sb->s_maxlen) > journal->j_total_len) { + printk(KERN_WARNING "JBD2: journal file too short\n"); + goto out; + } + + if (be32_to_cpu(sb->s_first) == 0 || + be32_to_cpu(sb->s_first) >= journal->j_total_len) { + printk(KERN_WARNING + "JBD2: Invalid start block of journal: %u\n", + be32_to_cpu(sb->s_first)); + goto out; + } + + if (jbd2_has_feature_csum2(journal) && + jbd2_has_feature_csum3(journal)) { + /* Can't have checksum v2 and v3 at the same time! */ + printk(KERN_ERR "JBD2: Can't enable checksumming v2 and v3 " + "at the same time!\n"); + goto out; + } + + if (jbd2_journal_has_csum_v2or3_feature(journal) && + jbd2_has_feature_checksum(journal)) { + /* Can't have checksum v1 and v2 on at the same time! */ + printk(KERN_ERR "JBD2: Can't enable checksumming v1 and v2/3 " + "at the same time!\n"); + goto out; + } + + if (!jbd2_verify_csum_type(journal, sb)) { + printk(KERN_ERR "JBD2: Unknown checksum type\n"); + goto out; + } + + /* Load the checksum driver */ + if (jbd2_journal_has_csum_v2or3_feature(journal)) { + journal->j_chksum_driver = crypto_alloc_shash("crc32c", 0, 0); + if (IS_ERR(journal->j_chksum_driver)) { + printk(KERN_ERR "JBD2: Cannot load crc32c driver.\n"); + err = PTR_ERR(journal->j_chksum_driver); + journal->j_chksum_driver = NULL; + goto out; + } + } + + if (jbd2_journal_has_csum_v2or3(journal)) { + /* Check superblock checksum */ + if (sb->s_checksum != jbd2_superblock_csum(journal, sb)) { + printk(KERN_ERR "JBD2: journal checksum error\n"); + err = -EFSBADCRC; + goto out; + } + + /* Precompute checksum seed for all metadata */ + journal->j_csum_seed = jbd2_chksum(journal, ~0, sb->s_uuid, + sizeof(sb->s_uuid)); + } + + journal->j_revoke_records_per_block = + journal_revoke_records_per_block(journal); + set_buffer_verified(bh); + + return 0; + +out: + journal_fail_superblock(journal); + return err; +} + +/* + * Load the on-disk journal superblock and read the key fields into the + * journal_t. + */ + +static int load_superblock(journal_t *journal) +{ + int err; + journal_superblock_t *sb; + int num_fc_blocks; + + err = journal_get_superblock(journal); + if (err) + return err; + + sb = journal->j_superblock; + + journal->j_tail_sequence = be32_to_cpu(sb->s_sequence); + journal->j_tail = be32_to_cpu(sb->s_start); + journal->j_first = be32_to_cpu(sb->s_first); + journal->j_errno = be32_to_cpu(sb->s_errno); + journal->j_last = be32_to_cpu(sb->s_maxlen); + + if (jbd2_has_feature_fast_commit(journal)) { + journal->j_fc_last = be32_to_cpu(sb->s_maxlen); + num_fc_blocks = be32_to_cpu(sb->s_num_fc_blks); + if (!num_fc_blocks) + num_fc_blocks = JBD2_MIN_FC_BLOCKS; + if (journal->j_last - num_fc_blocks >= JBD2_MIN_JOURNAL_BLOCKS) + journal->j_last = journal->j_fc_last - num_fc_blocks; + journal->j_fc_first = journal->j_last + 1; + journal->j_fc_off = 0; + } + + return 0; +} + + +/** + * jbd2_journal_load() - Read journal from disk. + * @journal: Journal to act on. + * + * Given a journal_t structure which tells us which disk blocks contain + * a journal, read the journal from disk to initialise the in-memory + * structures. + */ +int jbd2_journal_load(journal_t *journal) +{ + int err; + journal_superblock_t *sb; + + err = load_superblock(journal); + if (err) + return err; + + sb = journal->j_superblock; + /* If this is a V2 superblock, then we have to check the + * features flags on it. */ + + if (journal->j_format_version >= 2) { + if ((sb->s_feature_ro_compat & + ~cpu_to_be32(JBD2_KNOWN_ROCOMPAT_FEATURES)) || + (sb->s_feature_incompat & + ~cpu_to_be32(JBD2_KNOWN_INCOMPAT_FEATURES))) { + printk(KERN_WARNING + "JBD2: Unrecognised features on journal\n"); + return -EINVAL; + } + } + + /* + * Create a slab for this blocksize + */ + err = jbd2_journal_create_slab(be32_to_cpu(sb->s_blocksize)); + if (err) + return err; + + /* Let the recovery code check whether it needs to recover any + * data from the journal. */ + if (jbd2_journal_recover(journal)) + goto recovery_error; + + if (journal->j_failed_commit) { + printk(KERN_ERR "JBD2: journal transaction %u on %s " + "is corrupt.\n", journal->j_failed_commit, + journal->j_devname); + return -EFSCORRUPTED; + } + /* + * clear JBD2_ABORT flag initialized in journal_init_common + * here to update log tail information with the newest seq. + */ + journal->j_flags &= ~JBD2_ABORT; + + /* OK, we've finished with the dynamic journal bits: + * reinitialise the dynamic contents of the superblock in memory + * and reset them on disk. */ + if (journal_reset(journal)) + goto recovery_error; + + journal->j_flags |= JBD2_LOADED; + return 0; + +recovery_error: + printk(KERN_WARNING "JBD2: recovery failed\n"); + return -EIO; +} + +/** + * jbd2_journal_destroy() - Release a journal_t structure. + * @journal: Journal to act on. + * + * Release a journal_t structure once it is no longer in use by the + * journaled object. + * Return <0 if we couldn't clean up the journal. + */ +int jbd2_journal_destroy(journal_t *journal) +{ + int err = 0; + + /* Wait for the commit thread to wake up and die. */ + journal_kill_thread(journal); + + /* Force a final log commit */ + if (journal->j_running_transaction) + jbd2_journal_commit_transaction(journal); + + /* Force any old transactions to disk */ + + /* Totally anal locking here... */ + spin_lock(&journal->j_list_lock); + while (journal->j_checkpoint_transactions != NULL) { + spin_unlock(&journal->j_list_lock); + mutex_lock_io(&journal->j_checkpoint_mutex); + err = jbd2_log_do_checkpoint(journal); + mutex_unlock(&journal->j_checkpoint_mutex); + /* + * If checkpointing failed, just free the buffers to avoid + * looping forever + */ + if (err) { + jbd2_journal_destroy_checkpoint(journal); + spin_lock(&journal->j_list_lock); + break; + } + spin_lock(&journal->j_list_lock); + } + + J_ASSERT(journal->j_running_transaction == NULL); + J_ASSERT(journal->j_committing_transaction == NULL); + J_ASSERT(journal->j_checkpoint_transactions == NULL); + spin_unlock(&journal->j_list_lock); + + if (journal->j_sb_buffer) { + if (!is_journal_aborted(journal)) { + mutex_lock_io(&journal->j_checkpoint_mutex); + + write_lock(&journal->j_state_lock); + journal->j_tail_sequence = + ++journal->j_transaction_sequence; + write_unlock(&journal->j_state_lock); + + jbd2_mark_journal_empty(journal, + REQ_SYNC | REQ_PREFLUSH | REQ_FUA); + mutex_unlock(&journal->j_checkpoint_mutex); + } else + err = -EIO; + brelse(journal->j_sb_buffer); + } + + if (journal->j_proc_entry) + jbd2_stats_proc_exit(journal); + iput(journal->j_inode); + if (journal->j_revoke) + jbd2_journal_destroy_revoke(journal); + if (journal->j_chksum_driver) + crypto_free_shash(journal->j_chksum_driver); + kfree(journal->j_fc_wbuf); + kfree(journal->j_wbuf); + kfree(journal); + + return err; +} + + +/** + * jbd2_journal_check_used_features() - Check if features specified are used. + * @journal: Journal to check. + * @compat: bitmask of compatible features + * @ro: bitmask of features that force read-only mount + * @incompat: bitmask of incompatible features + * + * Check whether the journal uses all of a given set of + * features. Return true (non-zero) if it does. + **/ + +int jbd2_journal_check_used_features(journal_t *journal, unsigned long compat, + unsigned long ro, unsigned long incompat) +{ + journal_superblock_t *sb; + + if (!compat && !ro && !incompat) + return 1; + /* Load journal superblock if it is not loaded yet. */ + if (journal->j_format_version == 0 && + journal_get_superblock(journal) != 0) + return 0; + if (journal->j_format_version == 1) + return 0; + + sb = journal->j_superblock; + + if (((be32_to_cpu(sb->s_feature_compat) & compat) == compat) && + ((be32_to_cpu(sb->s_feature_ro_compat) & ro) == ro) && + ((be32_to_cpu(sb->s_feature_incompat) & incompat) == incompat)) + return 1; + + return 0; +} + +/** + * jbd2_journal_check_available_features() - Check feature set in journalling layer + * @journal: Journal to check. + * @compat: bitmask of compatible features + * @ro: bitmask of features that force read-only mount + * @incompat: bitmask of incompatible features + * + * Check whether the journaling code supports the use of + * all of a given set of features on this journal. Return true + * (non-zero) if it can. */ + +int jbd2_journal_check_available_features(journal_t *journal, unsigned long compat, + unsigned long ro, unsigned long incompat) +{ + if (!compat && !ro && !incompat) + return 1; + + /* We can support any known requested features iff the + * superblock is in version 2. Otherwise we fail to support any + * extended sb features. */ + + if (journal->j_format_version != 2) + return 0; + + if ((compat & JBD2_KNOWN_COMPAT_FEATURES) == compat && + (ro & JBD2_KNOWN_ROCOMPAT_FEATURES) == ro && + (incompat & JBD2_KNOWN_INCOMPAT_FEATURES) == incompat) + return 1; + + return 0; +} + +static int +jbd2_journal_initialize_fast_commit(journal_t *journal) +{ + journal_superblock_t *sb = journal->j_superblock; + unsigned long long num_fc_blks; + + num_fc_blks = be32_to_cpu(sb->s_num_fc_blks); + if (num_fc_blks == 0) + num_fc_blks = JBD2_MIN_FC_BLOCKS; + if (journal->j_last - num_fc_blks < JBD2_MIN_JOURNAL_BLOCKS) + return -ENOSPC; + + /* Are we called twice? */ + WARN_ON(journal->j_fc_wbuf != NULL); + journal->j_fc_wbuf = kmalloc_array(num_fc_blks, + sizeof(struct buffer_head *), GFP_KERNEL); + if (!journal->j_fc_wbuf) + return -ENOMEM; + + journal->j_fc_wbufsize = num_fc_blks; + journal->j_fc_last = journal->j_last; + journal->j_last = journal->j_fc_last - num_fc_blks; + journal->j_fc_first = journal->j_last + 1; + journal->j_fc_off = 0; + journal->j_free = journal->j_last - journal->j_first; + journal->j_max_transaction_buffers = + jbd2_journal_get_max_txn_bufs(journal); + + return 0; +} + +/** + * jbd2_journal_set_features() - Mark a given journal feature in the superblock + * @journal: Journal to act on. + * @compat: bitmask of compatible features + * @ro: bitmask of features that force read-only mount + * @incompat: bitmask of incompatible features + * + * Mark a given journal feature as present on the + * superblock. Returns true if the requested features could be set. + * + */ + +int jbd2_journal_set_features(journal_t *journal, unsigned long compat, + unsigned long ro, unsigned long incompat) +{ +#define INCOMPAT_FEATURE_ON(f) \ + ((incompat & (f)) && !(sb->s_feature_incompat & cpu_to_be32(f))) +#define COMPAT_FEATURE_ON(f) \ + ((compat & (f)) && !(sb->s_feature_compat & cpu_to_be32(f))) + journal_superblock_t *sb; + + if (jbd2_journal_check_used_features(journal, compat, ro, incompat)) + return 1; + + if (!jbd2_journal_check_available_features(journal, compat, ro, incompat)) + return 0; + + /* If enabling v2 checksums, turn on v3 instead */ + if (incompat & JBD2_FEATURE_INCOMPAT_CSUM_V2) { + incompat &= ~JBD2_FEATURE_INCOMPAT_CSUM_V2; + incompat |= JBD2_FEATURE_INCOMPAT_CSUM_V3; + } + + /* Asking for checksumming v3 and v1? Only give them v3. */ + if (incompat & JBD2_FEATURE_INCOMPAT_CSUM_V3 && + compat & JBD2_FEATURE_COMPAT_CHECKSUM) + compat &= ~JBD2_FEATURE_COMPAT_CHECKSUM; + + jbd_debug(1, "Setting new features 0x%lx/0x%lx/0x%lx\n", + compat, ro, incompat); + + sb = journal->j_superblock; + + if (incompat & JBD2_FEATURE_INCOMPAT_FAST_COMMIT) { + if (jbd2_journal_initialize_fast_commit(journal)) { + pr_err("JBD2: Cannot enable fast commits.\n"); + return 0; + } + } + + /* Load the checksum driver if necessary */ + if ((journal->j_chksum_driver == NULL) && + INCOMPAT_FEATURE_ON(JBD2_FEATURE_INCOMPAT_CSUM_V3)) { + journal->j_chksum_driver = crypto_alloc_shash("crc32c", 0, 0); + if (IS_ERR(journal->j_chksum_driver)) { + printk(KERN_ERR "JBD2: Cannot load crc32c driver.\n"); + journal->j_chksum_driver = NULL; + return 0; + } + /* Precompute checksum seed for all metadata */ + journal->j_csum_seed = jbd2_chksum(journal, ~0, sb->s_uuid, + sizeof(sb->s_uuid)); + } + + lock_buffer(journal->j_sb_buffer); + + /* If enabling v3 checksums, update superblock */ + if (INCOMPAT_FEATURE_ON(JBD2_FEATURE_INCOMPAT_CSUM_V3)) { + sb->s_checksum_type = JBD2_CRC32C_CHKSUM; + sb->s_feature_compat &= + ~cpu_to_be32(JBD2_FEATURE_COMPAT_CHECKSUM); + } + + /* If enabling v1 checksums, downgrade superblock */ + if (COMPAT_FEATURE_ON(JBD2_FEATURE_COMPAT_CHECKSUM)) + sb->s_feature_incompat &= + ~cpu_to_be32(JBD2_FEATURE_INCOMPAT_CSUM_V2 | + JBD2_FEATURE_INCOMPAT_CSUM_V3); + + sb->s_feature_compat |= cpu_to_be32(compat); + sb->s_feature_ro_compat |= cpu_to_be32(ro); + sb->s_feature_incompat |= cpu_to_be32(incompat); + unlock_buffer(journal->j_sb_buffer); + journal->j_revoke_records_per_block = + journal_revoke_records_per_block(journal); + + return 1; +#undef COMPAT_FEATURE_ON +#undef INCOMPAT_FEATURE_ON +} + +/* + * jbd2_journal_clear_features() - Clear a given journal feature in the + * superblock + * @journal: Journal to act on. + * @compat: bitmask of compatible features + * @ro: bitmask of features that force read-only mount + * @incompat: bitmask of incompatible features + * + * Clear a given journal feature as present on the + * superblock. + */ +void jbd2_journal_clear_features(journal_t *journal, unsigned long compat, + unsigned long ro, unsigned long incompat) +{ + journal_superblock_t *sb; + + jbd_debug(1, "Clear features 0x%lx/0x%lx/0x%lx\n", + compat, ro, incompat); + + sb = journal->j_superblock; + + sb->s_feature_compat &= ~cpu_to_be32(compat); + sb->s_feature_ro_compat &= ~cpu_to_be32(ro); + sb->s_feature_incompat &= ~cpu_to_be32(incompat); + journal->j_revoke_records_per_block = + journal_revoke_records_per_block(journal); +} +EXPORT_SYMBOL(jbd2_journal_clear_features); + +/** + * jbd2_journal_flush() - Flush journal + * @journal: Journal to act on. + * + * Flush all data for a given journal to disk and empty the journal. + * Filesystems can use this when remounting readonly to ensure that + * recovery does not need to happen on remount. + */ + +int jbd2_journal_flush(journal_t *journal) +{ + int err = 0; + transaction_t *transaction = NULL; + + write_lock(&journal->j_state_lock); + + /* Force everything buffered to the log... */ + if (journal->j_running_transaction) { + transaction = journal->j_running_transaction; + __jbd2_log_start_commit(journal, transaction->t_tid); + } else if (journal->j_committing_transaction) + transaction = journal->j_committing_transaction; + + /* Wait for the log commit to complete... */ + if (transaction) { + tid_t tid = transaction->t_tid; + + write_unlock(&journal->j_state_lock); + jbd2_log_wait_commit(journal, tid); + } else { + write_unlock(&journal->j_state_lock); + } + + /* ...and flush everything in the log out to disk. */ + spin_lock(&journal->j_list_lock); + while (!err && journal->j_checkpoint_transactions != NULL) { + spin_unlock(&journal->j_list_lock); + mutex_lock_io(&journal->j_checkpoint_mutex); + err = jbd2_log_do_checkpoint(journal); + mutex_unlock(&journal->j_checkpoint_mutex); + spin_lock(&journal->j_list_lock); + } + spin_unlock(&journal->j_list_lock); + + if (is_journal_aborted(journal)) + return -EIO; + + mutex_lock_io(&journal->j_checkpoint_mutex); + if (!err) { + err = jbd2_cleanup_journal_tail(journal); + if (err < 0) { + mutex_unlock(&journal->j_checkpoint_mutex); + goto out; + } + err = 0; + } + + /* Finally, mark the journal as really needing no recovery. + * This sets s_start==0 in the underlying superblock, which is + * the magic code for a fully-recovered superblock. Any future + * commits of data to the journal will restore the current + * s_start value. */ + jbd2_mark_journal_empty(journal, REQ_SYNC | REQ_FUA); + mutex_unlock(&journal->j_checkpoint_mutex); + write_lock(&journal->j_state_lock); + J_ASSERT(!journal->j_running_transaction); + J_ASSERT(!journal->j_committing_transaction); + J_ASSERT(!journal->j_checkpoint_transactions); + J_ASSERT(journal->j_head == journal->j_tail); + J_ASSERT(journal->j_tail_sequence == journal->j_transaction_sequence); + write_unlock(&journal->j_state_lock); +out: + return err; +} + +/** + * jbd2_journal_wipe() - Wipe journal contents + * @journal: Journal to act on. + * @write: flag (see below) + * + * Wipe out all of the contents of a journal, safely. This will produce + * a warning if the journal contains any valid recovery information. + * Must be called between journal_init_*() and jbd2_journal_load(). + * + * If 'write' is non-zero, then we wipe out the journal on disk; otherwise + * we merely suppress recovery. + */ + +int jbd2_journal_wipe(journal_t *journal, int write) +{ + int err = 0; + + J_ASSERT (!(journal->j_flags & JBD2_LOADED)); + + err = load_superblock(journal); + if (err) + return err; + + if (!journal->j_tail) + goto no_recovery; + + printk(KERN_WARNING "JBD2: %s recovery information on journal\n", + write ? "Clearing" : "Ignoring"); + + err = jbd2_journal_skip_recovery(journal); + if (write) { + /* Lock to make assertions happy... */ + mutex_lock_io(&journal->j_checkpoint_mutex); + jbd2_mark_journal_empty(journal, REQ_SYNC | REQ_FUA); + mutex_unlock(&journal->j_checkpoint_mutex); + } + + no_recovery: + return err; +} + +/** + * jbd2_journal_abort () - Shutdown the journal immediately. + * @journal: the journal to shutdown. + * @errno: an error number to record in the journal indicating + * the reason for the shutdown. + * + * Perform a complete, immediate shutdown of the ENTIRE + * journal (not of a single transaction). This operation cannot be + * undone without closing and reopening the journal. + * + * The jbd2_journal_abort function is intended to support higher level error + * recovery mechanisms such as the ext2/ext3 remount-readonly error + * mode. + * + * Journal abort has very specific semantics. Any existing dirty, + * unjournaled buffers in the main filesystem will still be written to + * disk by bdflush, but the journaling mechanism will be suspended + * immediately and no further transaction commits will be honoured. + * + * Any dirty, journaled buffers will be written back to disk without + * hitting the journal. Atomicity cannot be guaranteed on an aborted + * filesystem, but we _do_ attempt to leave as much data as possible + * behind for fsck to use for cleanup. + * + * Any attempt to get a new transaction handle on a journal which is in + * ABORT state will just result in an -EROFS error return. A + * jbd2_journal_stop on an existing handle will return -EIO if we have + * entered abort state during the update. + * + * Recursive transactions are not disturbed by journal abort until the + * final jbd2_journal_stop, which will receive the -EIO error. + * + * Finally, the jbd2_journal_abort call allows the caller to supply an errno + * which will be recorded (if possible) in the journal superblock. This + * allows a client to record failure conditions in the middle of a + * transaction without having to complete the transaction to record the + * failure to disk. ext3_error, for example, now uses this + * functionality. + * + */ + +void jbd2_journal_abort(journal_t *journal, int errno) +{ + transaction_t *transaction; + + /* + * Lock the aborting procedure until everything is done, this avoid + * races between filesystem's error handling flow (e.g. ext4_abort()), + * ensure panic after the error info is written into journal's + * superblock. + */ + mutex_lock(&journal->j_abort_mutex); + /* + * ESHUTDOWN always takes precedence because a file system check + * caused by any other journal abort error is not required after + * a shutdown triggered. + */ + write_lock(&journal->j_state_lock); + if (journal->j_flags & JBD2_ABORT) { + int old_errno = journal->j_errno; + + write_unlock(&journal->j_state_lock); + if (old_errno != -ESHUTDOWN && errno == -ESHUTDOWN) { + journal->j_errno = errno; + jbd2_journal_update_sb_errno(journal); + } + mutex_unlock(&journal->j_abort_mutex); + return; + } + + /* + * Mark the abort as occurred and start current running transaction + * to release all journaled buffer. + */ + pr_err("Aborting journal on device %s.\n", journal->j_devname); + + journal->j_flags |= JBD2_ABORT; + journal->j_errno = errno; + transaction = journal->j_running_transaction; + if (transaction) + __jbd2_log_start_commit(journal, transaction->t_tid); + write_unlock(&journal->j_state_lock); + + /* + * Record errno to the journal super block, so that fsck and jbd2 + * layer could realise that a filesystem check is needed. + */ + jbd2_journal_update_sb_errno(journal); + mutex_unlock(&journal->j_abort_mutex); +} + +/** + * jbd2_journal_errno() - returns the journal's error state. + * @journal: journal to examine. + * + * This is the errno number set with jbd2_journal_abort(), the last + * time the journal was mounted - if the journal was stopped + * without calling abort this will be 0. + * + * If the journal has been aborted on this mount time -EROFS will + * be returned. + */ +int jbd2_journal_errno(journal_t *journal) +{ + int err; + + read_lock(&journal->j_state_lock); + if (journal->j_flags & JBD2_ABORT) + err = -EROFS; + else + err = journal->j_errno; + read_unlock(&journal->j_state_lock); + return err; +} + +/** + * jbd2_journal_clear_err() - clears the journal's error state + * @journal: journal to act on. + * + * An error must be cleared or acked to take a FS out of readonly + * mode. + */ +int jbd2_journal_clear_err(journal_t *journal) +{ + int err = 0; + + write_lock(&journal->j_state_lock); + if (journal->j_flags & JBD2_ABORT) + err = -EROFS; + else + journal->j_errno = 0; + write_unlock(&journal->j_state_lock); + return err; +} + +/** + * jbd2_journal_ack_err() - Ack journal err. + * @journal: journal to act on. + * + * An error must be cleared or acked to take a FS out of readonly + * mode. + */ +void jbd2_journal_ack_err(journal_t *journal) +{ + write_lock(&journal->j_state_lock); + if (journal->j_errno) + journal->j_flags |= JBD2_ACK_ERR; + write_unlock(&journal->j_state_lock); +} + +int jbd2_journal_blocks_per_page(struct inode *inode) +{ + return 1 << (PAGE_SHIFT - inode->i_sb->s_blocksize_bits); +} + +/* + * helper functions to deal with 32 or 64bit block numbers. + */ +size_t journal_tag_bytes(journal_t *journal) +{ + size_t sz; + + if (jbd2_has_feature_csum3(journal)) + return sizeof(journal_block_tag3_t); + + sz = sizeof(journal_block_tag_t); + + if (jbd2_has_feature_csum2(journal)) + sz += sizeof(__u16); + + if (jbd2_has_feature_64bit(journal)) + return sz; + else + return sz - sizeof(__u32); +} + +/* + * JBD memory management + * + * These functions are used to allocate block-sized chunks of memory + * used for making copies of buffer_head data. Very often it will be + * page-sized chunks of data, but sometimes it will be in + * sub-page-size chunks. (For example, 16k pages on Power systems + * with a 4k block file system.) For blocks smaller than a page, we + * use a SLAB allocator. There are slab caches for each block size, + * which are allocated at mount time, if necessary, and we only free + * (all of) the slab caches when/if the jbd2 module is unloaded. For + * this reason we don't need to a mutex to protect access to + * jbd2_slab[] allocating or releasing memory; only in + * jbd2_journal_create_slab(). + */ +#define JBD2_MAX_SLABS 8 +static struct kmem_cache *jbd2_slab[JBD2_MAX_SLABS]; + +static const char *jbd2_slab_names[JBD2_MAX_SLABS] = { + "jbd2_1k", "jbd2_2k", "jbd2_4k", "jbd2_8k", + "jbd2_16k", "jbd2_32k", "jbd2_64k", "jbd2_128k" +}; + + +static void jbd2_journal_destroy_slabs(void) +{ + int i; + + for (i = 0; i < JBD2_MAX_SLABS; i++) { + kmem_cache_destroy(jbd2_slab[i]); + jbd2_slab[i] = NULL; + } +} + +static int jbd2_journal_create_slab(size_t size) +{ + static DEFINE_MUTEX(jbd2_slab_create_mutex); + int i = order_base_2(size) - 10; + size_t slab_size; + + if (size == PAGE_SIZE) + return 0; + + if (i >= JBD2_MAX_SLABS) + return -EINVAL; + + if (unlikely(i < 0)) + i = 0; + mutex_lock(&jbd2_slab_create_mutex); + if (jbd2_slab[i]) { + mutex_unlock(&jbd2_slab_create_mutex); + return 0; /* Already created */ + } + + slab_size = 1 << (i+10); + jbd2_slab[i] = kmem_cache_create(jbd2_slab_names[i], slab_size, + slab_size, 0, NULL); + mutex_unlock(&jbd2_slab_create_mutex); + if (!jbd2_slab[i]) { + printk(KERN_EMERG "JBD2: no memory for jbd2_slab cache\n"); + return -ENOMEM; + } + return 0; +} + +static struct kmem_cache *get_slab(size_t size) +{ + int i = order_base_2(size) - 10; + + BUG_ON(i >= JBD2_MAX_SLABS); + if (unlikely(i < 0)) + i = 0; + BUG_ON(jbd2_slab[i] == NULL); + return jbd2_slab[i]; +} + +void *jbd2_alloc(size_t size, gfp_t flags) +{ + void *ptr; + + BUG_ON(size & (size-1)); /* Must be a power of 2 */ + + if (size < PAGE_SIZE) + ptr = kmem_cache_alloc(get_slab(size), flags); + else + ptr = (void *)__get_free_pages(flags, get_order(size)); + + /* Check alignment; SLUB has gotten this wrong in the past, + * and this can lead to user data corruption! */ + BUG_ON(((unsigned long) ptr) & (size-1)); + + return ptr; +} + +void jbd2_free(void *ptr, size_t size) +{ + if (size < PAGE_SIZE) + kmem_cache_free(get_slab(size), ptr); + else + free_pages((unsigned long)ptr, get_order(size)); +}; + +/* + * Journal_head storage management + */ +static struct kmem_cache *jbd2_journal_head_cache; +#ifdef CONFIG_JBD2_DEBUG +static atomic_t nr_journal_heads = ATOMIC_INIT(0); +#endif + +static int __init jbd2_journal_init_journal_head_cache(void) +{ + J_ASSERT(!jbd2_journal_head_cache); + jbd2_journal_head_cache = kmem_cache_create("jbd2_journal_head", + sizeof(struct journal_head), + 0, /* offset */ + SLAB_TEMPORARY | SLAB_TYPESAFE_BY_RCU, + NULL); /* ctor */ + if (!jbd2_journal_head_cache) { + printk(KERN_EMERG "JBD2: no memory for journal_head cache\n"); + return -ENOMEM; + } + return 0; +} + +static void jbd2_journal_destroy_journal_head_cache(void) +{ + kmem_cache_destroy(jbd2_journal_head_cache); + jbd2_journal_head_cache = NULL; +} + +/* + * journal_head splicing and dicing + */ +static struct journal_head *journal_alloc_journal_head(void) +{ + struct journal_head *ret; + +#ifdef CONFIG_JBD2_DEBUG + atomic_inc(&nr_journal_heads); +#endif + ret = kmem_cache_zalloc(jbd2_journal_head_cache, GFP_NOFS); + if (!ret) { + jbd_debug(1, "out of memory for journal_head\n"); + pr_notice_ratelimited("ENOMEM in %s, retrying.\n", __func__); + ret = kmem_cache_zalloc(jbd2_journal_head_cache, + GFP_NOFS | __GFP_NOFAIL); + } + if (ret) + spin_lock_init(&ret->b_state_lock); + return ret; +} + +static void journal_free_journal_head(struct journal_head *jh) +{ +#ifdef CONFIG_JBD2_DEBUG + atomic_dec(&nr_journal_heads); + memset(jh, JBD2_POISON_FREE, sizeof(*jh)); +#endif + kmem_cache_free(jbd2_journal_head_cache, jh); +} + +/* + * A journal_head is attached to a buffer_head whenever JBD has an + * interest in the buffer. + * + * Whenever a buffer has an attached journal_head, its ->b_state:BH_JBD bit + * is set. This bit is tested in core kernel code where we need to take + * JBD-specific actions. Testing the zeroness of ->b_private is not reliable + * there. + * + * When a buffer has its BH_JBD bit set, its ->b_count is elevated by one. + * + * When a buffer has its BH_JBD bit set it is immune from being released by + * core kernel code, mainly via ->b_count. + * + * A journal_head is detached from its buffer_head when the journal_head's + * b_jcount reaches zero. Running transaction (b_transaction) and checkpoint + * transaction (b_cp_transaction) hold their references to b_jcount. + * + * Various places in the kernel want to attach a journal_head to a buffer_head + * _before_ attaching the journal_head to a transaction. To protect the + * journal_head in this situation, jbd2_journal_add_journal_head elevates the + * journal_head's b_jcount refcount by one. The caller must call + * jbd2_journal_put_journal_head() to undo this. + * + * So the typical usage would be: + * + * (Attach a journal_head if needed. Increments b_jcount) + * struct journal_head *jh = jbd2_journal_add_journal_head(bh); + * ... + * (Get another reference for transaction) + * jbd2_journal_grab_journal_head(bh); + * jh->b_transaction = xxx; + * (Put original reference) + * jbd2_journal_put_journal_head(jh); + */ + +/* + * Give a buffer_head a journal_head. + * + * May sleep. + */ +struct journal_head *jbd2_journal_add_journal_head(struct buffer_head *bh) +{ + struct journal_head *jh; + struct journal_head *new_jh = NULL; + +repeat: + if (!buffer_jbd(bh)) + new_jh = journal_alloc_journal_head(); + + jbd_lock_bh_journal_head(bh); + if (buffer_jbd(bh)) { + jh = bh2jh(bh); + } else { + J_ASSERT_BH(bh, + (atomic_read(&bh->b_count) > 0) || + (bh->b_page && bh->b_page->mapping)); + + if (!new_jh) { + jbd_unlock_bh_journal_head(bh); + goto repeat; + } + + jh = new_jh; + new_jh = NULL; /* We consumed it */ + set_buffer_jbd(bh); + bh->b_private = jh; + jh->b_bh = bh; + get_bh(bh); + BUFFER_TRACE(bh, "added journal_head"); + } + jh->b_jcount++; + jbd_unlock_bh_journal_head(bh); + if (new_jh) + journal_free_journal_head(new_jh); + return bh->b_private; +} + +/* + * Grab a ref against this buffer_head's journal_head. If it ended up not + * having a journal_head, return NULL + */ +struct journal_head *jbd2_journal_grab_journal_head(struct buffer_head *bh) +{ + struct journal_head *jh = NULL; + + jbd_lock_bh_journal_head(bh); + if (buffer_jbd(bh)) { + jh = bh2jh(bh); + jh->b_jcount++; + } + jbd_unlock_bh_journal_head(bh); + return jh; +} +EXPORT_SYMBOL(jbd2_journal_grab_journal_head); + +static void __journal_remove_journal_head(struct buffer_head *bh) +{ + struct journal_head *jh = bh2jh(bh); + + J_ASSERT_JH(jh, jh->b_transaction == NULL); + J_ASSERT_JH(jh, jh->b_next_transaction == NULL); + J_ASSERT_JH(jh, jh->b_cp_transaction == NULL); + J_ASSERT_JH(jh, jh->b_jlist == BJ_None); + J_ASSERT_BH(bh, buffer_jbd(bh)); + J_ASSERT_BH(bh, jh2bh(jh) == bh); + BUFFER_TRACE(bh, "remove journal_head"); + + /* Unlink before dropping the lock */ + bh->b_private = NULL; + jh->b_bh = NULL; /* debug, really */ + clear_buffer_jbd(bh); +} + +static void journal_release_journal_head(struct journal_head *jh, size_t b_size) +{ + if (jh->b_frozen_data) { + printk(KERN_WARNING "%s: freeing b_frozen_data\n", __func__); + jbd2_free(jh->b_frozen_data, b_size); + } + if (jh->b_committed_data) { + printk(KERN_WARNING "%s: freeing b_committed_data\n", __func__); + jbd2_free(jh->b_committed_data, b_size); + } + journal_free_journal_head(jh); +} + +/* + * Drop a reference on the passed journal_head. If it fell to zero then + * release the journal_head from the buffer_head. + */ +void jbd2_journal_put_journal_head(struct journal_head *jh) +{ + struct buffer_head *bh = jh2bh(jh); + + jbd_lock_bh_journal_head(bh); + J_ASSERT_JH(jh, jh->b_jcount > 0); + --jh->b_jcount; + if (!jh->b_jcount) { + __journal_remove_journal_head(bh); + jbd_unlock_bh_journal_head(bh); + journal_release_journal_head(jh, bh->b_size); + __brelse(bh); + } else { + jbd_unlock_bh_journal_head(bh); + } +} +EXPORT_SYMBOL(jbd2_journal_put_journal_head); + +/* + * Initialize jbd inode head + */ +void jbd2_journal_init_jbd_inode(struct jbd2_inode *jinode, struct inode *inode) +{ + jinode->i_transaction = NULL; + jinode->i_next_transaction = NULL; + jinode->i_vfs_inode = inode; + jinode->i_flags = 0; + jinode->i_dirty_start = 0; + jinode->i_dirty_end = 0; + INIT_LIST_HEAD(&jinode->i_list); +} + +/* + * Function to be called before we start removing inode from memory (i.e., + * clear_inode() is a fine place to be called from). It removes inode from + * transaction's lists. + */ +void jbd2_journal_release_jbd_inode(journal_t *journal, + struct jbd2_inode *jinode) +{ + if (!journal) + return; +restart: + spin_lock(&journal->j_list_lock); + /* Is commit writing out inode - we have to wait */ + if (jinode->i_flags & JI_COMMIT_RUNNING) { + wait_queue_head_t *wq; + DEFINE_WAIT_BIT(wait, &jinode->i_flags, __JI_COMMIT_RUNNING); + wq = bit_waitqueue(&jinode->i_flags, __JI_COMMIT_RUNNING); + prepare_to_wait(wq, &wait.wq_entry, TASK_UNINTERRUPTIBLE); + spin_unlock(&journal->j_list_lock); + schedule(); + finish_wait(wq, &wait.wq_entry); + goto restart; + } + + if (jinode->i_transaction) { + list_del(&jinode->i_list); + jinode->i_transaction = NULL; + } + spin_unlock(&journal->j_list_lock); +} + + +#ifdef CONFIG_PROC_FS + +#define JBD2_STATS_PROC_NAME "fs/jbd2" + +static void __init jbd2_create_jbd_stats_proc_entry(void) +{ + proc_jbd2_stats = proc_mkdir(JBD2_STATS_PROC_NAME, NULL); +} + +static void __exit jbd2_remove_jbd_stats_proc_entry(void) +{ + if (proc_jbd2_stats) + remove_proc_entry(JBD2_STATS_PROC_NAME, NULL); +} + +#else + +#define jbd2_create_jbd_stats_proc_entry() do {} while (0) +#define jbd2_remove_jbd_stats_proc_entry() do {} while (0) + +#endif + +struct kmem_cache *jbd2_handle_cache, *jbd2_inode_cache; + +static int __init jbd2_journal_init_inode_cache(void) +{ + J_ASSERT(!jbd2_inode_cache); + jbd2_inode_cache = KMEM_CACHE(jbd2_inode, 0); + if (!jbd2_inode_cache) { + pr_emerg("JBD2: failed to create inode cache\n"); + return -ENOMEM; + } + return 0; +} + +static int __init jbd2_journal_init_handle_cache(void) +{ + J_ASSERT(!jbd2_handle_cache); + jbd2_handle_cache = KMEM_CACHE(jbd2_journal_handle, SLAB_TEMPORARY); + if (!jbd2_handle_cache) { + printk(KERN_EMERG "JBD2: failed to create handle cache\n"); + return -ENOMEM; + } + return 0; +} + +static void jbd2_journal_destroy_inode_cache(void) +{ + kmem_cache_destroy(jbd2_inode_cache); + jbd2_inode_cache = NULL; +} + +static void jbd2_journal_destroy_handle_cache(void) +{ + kmem_cache_destroy(jbd2_handle_cache); + jbd2_handle_cache = NULL; +} + +/* + * Module startup and shutdown + */ + +static int __init journal_init_caches(void) +{ + int ret; + + ret = jbd2_journal_init_revoke_record_cache(); + if (ret == 0) + ret = jbd2_journal_init_revoke_table_cache(); + if (ret == 0) + ret = jbd2_journal_init_journal_head_cache(); + if (ret == 0) + ret = jbd2_journal_init_handle_cache(); + if (ret == 0) + ret = jbd2_journal_init_inode_cache(); + if (ret == 0) + ret = jbd2_journal_init_transaction_cache(); + return ret; +} + +static void jbd2_journal_destroy_caches(void) +{ + jbd2_journal_destroy_revoke_record_cache(); + jbd2_journal_destroy_revoke_table_cache(); + jbd2_journal_destroy_journal_head_cache(); + jbd2_journal_destroy_handle_cache(); + jbd2_journal_destroy_inode_cache(); + jbd2_journal_destroy_transaction_cache(); + jbd2_journal_destroy_slabs(); +} + +static int __init journal_init(void) +{ + int ret; + + BUILD_BUG_ON(sizeof(struct journal_superblock_s) != 1024); + + ret = journal_init_caches(); + if (ret == 0) { + jbd2_create_jbd_stats_proc_entry(); + } else { + jbd2_journal_destroy_caches(); + } + return ret; +} + +static void __exit journal_exit(void) +{ +#ifdef CONFIG_JBD2_DEBUG + int n = atomic_read(&nr_journal_heads); + if (n) + printk(KERN_ERR "JBD2: leaked %d journal_heads!\n", n); +#endif + jbd2_remove_jbd_stats_proc_entry(); + jbd2_journal_destroy_caches(); +} + +MODULE_LICENSE("GPL"); +module_init(journal_init); +module_exit(journal_exit); + |