diff options
Diffstat (limited to 'kernel/fs/jbd/journal.c')
| -rw-r--r-- | kernel/fs/jbd/journal.c | 2145 |
1 files changed, 0 insertions, 2145 deletions
diff --git a/kernel/fs/jbd/journal.c b/kernel/fs/jbd/journal.c deleted file mode 100644 index c46a79adb..000000000 --- a/kernel/fs/jbd/journal.c +++ /dev/null @@ -1,2145 +0,0 @@ -/* - * linux/fs/jbd/journal.c - * - * Written by Stephen C. Tweedie <sct@redhat.com>, 1998 - * - * Copyright 1998 Red Hat corp --- All Rights Reserved - * - * This file is part of the Linux kernel and is made available under - * the terms of the GNU General Public License, version 2, or at your - * option, any later version, incorporated herein by reference. - * - * 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/jbd.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/debugfs.h> -#include <linux/ratelimit.h> - -#define CREATE_TRACE_POINTS -#include <trace/events/jbd.h> - -#include <asm/uaccess.h> -#include <asm/page.h> - -EXPORT_SYMBOL(journal_start); -EXPORT_SYMBOL(journal_restart); -EXPORT_SYMBOL(journal_extend); -EXPORT_SYMBOL(journal_stop); -EXPORT_SYMBOL(journal_lock_updates); -EXPORT_SYMBOL(journal_unlock_updates); -EXPORT_SYMBOL(journal_get_write_access); -EXPORT_SYMBOL(journal_get_create_access); -EXPORT_SYMBOL(journal_get_undo_access); -EXPORT_SYMBOL(journal_dirty_data); -EXPORT_SYMBOL(journal_dirty_metadata); -EXPORT_SYMBOL(journal_release_buffer); -EXPORT_SYMBOL(journal_forget); -#if 0 -EXPORT_SYMBOL(journal_sync_buffer); -#endif -EXPORT_SYMBOL(journal_flush); -EXPORT_SYMBOL(journal_revoke); - -EXPORT_SYMBOL(journal_init_dev); -EXPORT_SYMBOL(journal_init_inode); -EXPORT_SYMBOL(journal_update_format); -EXPORT_SYMBOL(journal_check_used_features); -EXPORT_SYMBOL(journal_check_available_features); -EXPORT_SYMBOL(journal_set_features); -EXPORT_SYMBOL(journal_create); -EXPORT_SYMBOL(journal_load); -EXPORT_SYMBOL(journal_destroy); -EXPORT_SYMBOL(journal_abort); -EXPORT_SYMBOL(journal_errno); -EXPORT_SYMBOL(journal_ack_err); -EXPORT_SYMBOL(journal_clear_err); -EXPORT_SYMBOL(log_wait_commit); -EXPORT_SYMBOL(log_start_commit); -EXPORT_SYMBOL(journal_start_commit); -EXPORT_SYMBOL(journal_force_commit_nested); -EXPORT_SYMBOL(journal_wipe); -EXPORT_SYMBOL(journal_blocks_per_page); -EXPORT_SYMBOL(journal_invalidatepage); -EXPORT_SYMBOL(journal_try_to_free_buffers); -EXPORT_SYMBOL(journal_force_commit); - -static int journal_convert_superblock_v1(journal_t *, journal_superblock_t *); -static void __journal_abort_soft (journal_t *journal, int errno); -static const char *journal_dev_name(journal_t *journal, char *buffer); - -#ifdef CONFIG_JBD_DEBUG -void __jbd_debug(int level, const char *file, const char *func, - unsigned int line, const char *fmt, ...) -{ - struct va_format vaf; - va_list args; - - if (level > journal_enable_debug) - return; - va_start(args, fmt); - vaf.fmt = fmt; - vaf.va = &args; - printk(KERN_DEBUG "%s: (%s, %u): %pV\n", file, func, line, &vaf); - va_end(args); -} -EXPORT_SYMBOL(__jbd_debug); -#endif - -/* - * Helper function used to manage commit timeouts - */ - -static void commit_timeout(unsigned long __data) -{ - struct task_struct * p = (struct task_struct *) __data; - - wake_up_process(p); -} - -/* - * kjournald: 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. - * - * 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 kjournald(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 - */ - setup_timer(&journal->j_commit_timer, commit_timeout, - (unsigned long)current); - - set_freezable(); - - /* Record that the journal thread is running */ - journal->j_task = current; - wake_up(&journal->j_wait_done_commit); - - printk(KERN_INFO "kjournald starting. Commit interval %ld seconds\n", - journal->j_commit_interval / HZ); - - /* - * And now, wait forever for commit wakeup events. - */ - spin_lock(&journal->j_state_lock); - -loop: - if (journal->j_flags & JFS_UNMOUNT) - goto end_loop; - - jbd_debug(1, "commit_sequence=%d, commit_request=%d\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"); - spin_unlock(&journal->j_state_lock); - del_timer_sync(&journal->j_commit_timer); - journal_commit_transaction(journal); - spin_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 kjournald\n"); - spin_unlock(&journal->j_state_lock); - try_to_freeze(); - spin_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 & JFS_UNMOUNT) - should_sleep = 0; - if (should_sleep) { - spin_unlock(&journal->j_state_lock); - schedule(); - spin_lock(&journal->j_state_lock); - } - finish_wait(&journal->j_wait_commit, &wait); - } - - jbd_debug(1, "kjournald 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: - spin_unlock(&journal->j_state_lock); - 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"); - return 0; -} - -static int journal_start_thread(journal_t *journal) -{ - struct task_struct *t; - - t = kthread_run(kjournald, journal, "kjournald"); - 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) -{ - spin_lock(&journal->j_state_lock); - journal->j_flags |= JFS_UNMOUNT; - - while (journal->j_task) { - wake_up(&journal->j_wait_commit); - spin_unlock(&journal->j_state_lock); - wait_event(journal->j_wait_done_commit, - journal->j_task == NULL); - spin_lock(&journal->j_state_lock); - } - spin_unlock(&journal->j_state_lock); -} - -/* - * 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 - * JFS_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 lock the buffer to prevent anyone - * else from using and possibly modifying it while the IO is in - * progress. - * - * The function returns a pointer to the buffer_heads to be used for IO. - * - * We assume that the journal has already been locked in this function. - * - * 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 journal_write_metadata_buffer(transaction_t *transaction, - struct journal_head *jh_in, - struct journal_head **jh_out, - unsigned int blocknr) -{ - int need_copy_out = 0; - int done_copy_out = 0; - int do_escape = 0; - char *mapped_data; - struct buffer_head *new_bh; - struct journal_head *new_jh; - 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); - new_jh = journal_add_journal_head(new_bh); /* This sleeps */ - - /* - * If a new transaction has already done a buffer copy-out, then - * we use that version of the data for the commit. - */ - jbd_lock_bh_state(bh_in); -repeat: - 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); - /* - * Check for escaping - */ - if (*((__be32 *)(mapped_data + new_offset)) == - cpu_to_be32(JFS_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; - - jbd_unlock_bh_state(bh_in); - tmp = jbd_alloc(bh_in->b_size, GFP_NOFS); - jbd_lock_bh_state(bh_in); - if (jh_in->b_frozen_data) { - jbd_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, jh2bh(jh_in)->b_size); - kunmap_atomic(mapped_data); - - new_page = virt_to_page(tmp); - new_offset = offset_in_page(tmp); - done_copy_out = 1; - } - - /* - * 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_jh->b_transaction = NULL; - new_bh->b_size = jh2bh(jh_in)->b_size; - new_bh->b_bdev = transaction->t_journal->j_dev; - new_bh->b_blocknr = blocknr; - set_buffer_mapped(new_bh); - set_buffer_dirty(new_bh); - - *jh_out = new_jh; - - /* - * 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); - __journal_file_buffer(jh_in, transaction, BJ_Shadow); - spin_unlock(&journal->j_list_lock); - jbd_unlock_bh_state(bh_in); - - JBUFFER_TRACE(new_jh, "file as BJ_IO"); - journal_file_buffer(new_jh, transaction, BJ_IO); - - 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. - */ - -/* - * __log_space_left: Return the number of free blocks left in the journal. - * - * Called with the journal already locked. - * - * Called under j_state_lock - */ - -int __log_space_left(journal_t *journal) -{ - int left = journal->j_free; - - assert_spin_locked(&journal->j_state_lock); - - /* - * Be pessimistic here about the number of those free blocks which - * might be required for log descriptor control blocks. - */ - -#define MIN_LOG_RESERVED_BLOCKS 32 /* Allow for rounding errors */ - - left -= MIN_LOG_RESERVED_BLOCKS; - - if (left <= 0) - return 0; - left -= (left >> 3); - return left; -} - -/* - * Called under j_state_lock. Returns true if a transaction commit was started. - */ -int __log_start_commit(journal_t *journal, tid_t target) -{ - /* - * 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_commit_request != target && - 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, "JBD: requesting commit %d/%d\n", - journal->j_commit_request, - journal->j_commit_sequence); - 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, "jbd: 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 log_start_commit(journal_t *journal, tid_t tid) -{ - int ret; - - spin_lock(&journal->j_state_lock); - ret = __log_start_commit(journal, tid); - spin_unlock(&journal->j_state_lock); - return ret; -} - -/* - * Force and wait upon a commit if the calling process is not within - * transaction. This is used for forcing out undo-protected data which contains - * bitmaps, when the fs is running out of space. - * - * We can only force the running transaction if we don't have an active handle; - * otherwise, we will deadlock. - * - * Returns true if a transaction was started. - */ -int journal_force_commit_nested(journal_t *journal) -{ - transaction_t *transaction = NULL; - tid_t tid; - - spin_lock(&journal->j_state_lock); - if (journal->j_running_transaction && !current->journal_info) { - transaction = journal->j_running_transaction; - __log_start_commit(journal, transaction->t_tid); - } else if (journal->j_committing_transaction) - transaction = journal->j_committing_transaction; - - if (!transaction) { - spin_unlock(&journal->j_state_lock); - return 0; /* Nothing to retry */ - } - - tid = transaction->t_tid; - spin_unlock(&journal->j_state_lock); - log_wait_commit(journal, tid); - return 1; -} - -/* - * 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 journal_start_commit(journal_t *journal, tid_t *ptid) -{ - int ret = 0; - - spin_lock(&journal->j_state_lock); - if (journal->j_running_transaction) { - tid_t tid = journal->j_running_transaction->t_tid; - - __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; - } - spin_unlock(&journal->j_state_lock); - return ret; -} - -/* - * Wait for a specified commit to complete. - * The caller may not hold the journal lock. - */ -int log_wait_commit(journal_t *journal, tid_t tid) -{ - int err = 0; - -#ifdef CONFIG_JBD_DEBUG - spin_lock(&journal->j_state_lock); - if (!tid_geq(journal->j_commit_request, tid)) { - printk(KERN_ERR - "%s: error: j_commit_request=%d, tid=%d\n", - __func__, journal->j_commit_request, tid); - } - spin_unlock(&journal->j_state_lock); -#endif - spin_lock(&journal->j_state_lock); - /* - * Not running or committing trans? Must be already committed. This - * saves us from waiting for a *long* time when tid overflows. - */ - if (!((journal->j_running_transaction && - journal->j_running_transaction->t_tid == tid) || - (journal->j_committing_transaction && - journal->j_committing_transaction->t_tid == tid))) - goto out_unlock; - - if (!tid_geq(journal->j_commit_waited, tid)) - journal->j_commit_waited = tid; - while (tid_gt(tid, journal->j_commit_sequence)) { - jbd_debug(1, "JBD: want %d, j_commit_sequence=%d\n", - tid, journal->j_commit_sequence); - wake_up(&journal->j_wait_commit); - spin_unlock(&journal->j_state_lock); - wait_event(journal->j_wait_done_commit, - !tid_gt(tid, journal->j_commit_sequence)); - spin_lock(&journal->j_state_lock); - } -out_unlock: - spin_unlock(&journal->j_state_lock); - - if (unlikely(is_journal_aborted(journal))) - err = -EIO; - return err; -} - -/* - * 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 journal_trans_will_send_data_barrier(journal_t *journal, tid_t tid) -{ - int ret = 0; - transaction_t *commit_trans; - - if (!(journal->j_flags & JFS_BARRIER)) - return 0; - spin_lock(&journal->j_state_lock); - /* Transaction already committed? */ - if (tid_geq(journal->j_commit_sequence, tid)) - goto out; - /* - * Transaction is being committed and we already proceeded to - * writing commit record? - */ - commit_trans = journal->j_committing_transaction; - if (commit_trans && commit_trans->t_tid == tid && - commit_trans->t_state >= T_COMMIT_RECORD) - goto out; - ret = 1; -out: - spin_unlock(&journal->j_state_lock); - return ret; -} -EXPORT_SYMBOL(journal_trans_will_send_data_barrier); - -/* - * Log buffer allocation routines: - */ - -int journal_next_log_block(journal_t *journal, unsigned int *retp) -{ - unsigned int blocknr; - - spin_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; - spin_unlock(&journal->j_state_lock); - return journal_bmap(journal, blocknr, retp); -} - -/* - * 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 journal_bmap(journal_t *journal, unsigned int blocknr, - unsigned int *retp) -{ - int err = 0; - unsigned int ret; - - if (journal->j_inode) { - ret = bmap(journal->j_inode, blocknr); - if (ret) - *retp = ret; - else { - char b[BDEVNAME_SIZE]; - - printk(KERN_ALERT "%s: journal block not found " - "at offset %u on %s\n", - __func__, - blocknr, - bdevname(journal->j_dev, b)); - err = -EIO; - __journal_abort_soft(journal, err); - } - } 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 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 journal_head *journal_get_descriptor_buffer(journal_t *journal) -{ - struct buffer_head *bh; - unsigned int blocknr; - int err; - - err = journal_next_log_block(journal, &blocknr); - - if (err) - return NULL; - - bh = __getblk(journal->j_dev, blocknr, journal->j_blocksize); - if (!bh) - return NULL; - lock_buffer(bh); - memset(bh->b_data, 0, journal->j_blocksize); - set_buffer_uptodate(bh); - unlock_buffer(bh); - BUFFER_TRACE(bh, "return this buffer"); - return journal_add_journal_head(bh); -} - -/* - * 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 (void) -{ - journal_t *journal; - int err; - - journal = kzalloc(sizeof(*journal), GFP_KERNEL); - if (!journal) - goto fail; - - init_waitqueue_head(&journal->j_wait_transaction_locked); - init_waitqueue_head(&journal->j_wait_logspace); - init_waitqueue_head(&journal->j_wait_done_commit); - init_waitqueue_head(&journal->j_wait_checkpoint); - init_waitqueue_head(&journal->j_wait_commit); - init_waitqueue_head(&journal->j_wait_updates); - mutex_init(&journal->j_checkpoint_mutex); - spin_lock_init(&journal->j_revoke_lock); - spin_lock_init(&journal->j_list_lock); - spin_lock_init(&journal->j_state_lock); - - journal->j_commit_interval = (HZ * JBD_DEFAULT_MAX_COMMIT_AGE); - - /* The journal is marked for error until we succeed with recovery! */ - journal->j_flags = JFS_ABORT; - - /* Set up a default-sized revoke table for the new mount. */ - err = journal_init_revoke(journal, JOURNAL_REVOKE_DEFAULT_HASH); - if (err) { - kfree(journal); - goto fail; - } - return journal; -fail: - return NULL; -} - -/* journal_init_dev and 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 * 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 * - * - * journal_init_dev creates a journal which maps a fixed contiguous - * range of blocks on an arbitrary block device. - * - */ -journal_t * journal_init_dev(struct block_device *bdev, - struct block_device *fs_dev, - int start, int len, int blocksize) -{ - journal_t *journal = journal_init_common(); - struct buffer_head *bh; - int n; - - if (!journal) - return NULL; - - /* journal descriptor can store up to n blocks -bzzz */ - journal->j_blocksize = blocksize; - n = journal->j_blocksize / sizeof(journal_block_tag_t); - journal->j_wbufsize = n; - journal->j_wbuf = kmalloc(n * sizeof(struct buffer_head*), GFP_KERNEL); - if (!journal->j_wbuf) { - printk(KERN_ERR "%s: Can't allocate bhs for commit thread\n", - __func__); - goto out_err; - } - journal->j_dev = bdev; - journal->j_fs_dev = fs_dev; - journal->j_blk_offset = start; - journal->j_maxlen = len; - - bh = __getblk(journal->j_dev, start, journal->j_blocksize); - if (!bh) { - printk(KERN_ERR - "%s: Cannot get buffer for journal superblock\n", - __func__); - goto out_err; - } - journal->j_sb_buffer = bh; - journal->j_superblock = (journal_superblock_t *)bh->b_data; - - return journal; -out_err: - kfree(journal->j_wbuf); - kfree(journal); - return NULL; -} - -/** - * journal_t * journal_init_inode () - creates a journal which maps to a inode. - * @inode: An inode to create the journal in - * - * 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 * journal_init_inode (struct inode *inode) -{ - struct buffer_head *bh; - journal_t *journal = journal_init_common(); - int err; - int n; - unsigned int blocknr; - - if (!journal) - return NULL; - - journal->j_dev = journal->j_fs_dev = inode->i_sb->s_bdev; - journal->j_inode = inode; - jbd_debug(1, - "journal %p: inode %s/%ld, size %Ld, bits %d, blksize %ld\n", - journal, 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->j_maxlen = inode->i_size >> inode->i_sb->s_blocksize_bits; - journal->j_blocksize = inode->i_sb->s_blocksize; - - /* journal descriptor can store up to n blocks -bzzz */ - n = journal->j_blocksize / sizeof(journal_block_tag_t); - journal->j_wbufsize = n; - journal->j_wbuf = kmalloc(n * sizeof(struct buffer_head*), GFP_KERNEL); - if (!journal->j_wbuf) { - printk(KERN_ERR "%s: Can't allocate bhs for commit thread\n", - __func__); - goto out_err; - } - - err = journal_bmap(journal, 0, &blocknr); - /* If that failed, give up */ - if (err) { - printk(KERN_ERR "%s: Cannot locate journal superblock\n", - __func__); - goto out_err; - } - - bh = getblk_unmovable(journal->j_dev, blocknr, journal->j_blocksize); - if (!bh) { - printk(KERN_ERR - "%s: Cannot get buffer for journal superblock\n", - __func__); - goto out_err; - } - journal->j_sb_buffer = bh; - journal->j_superblock = (journal_superblock_t *)bh->b_data; - - return journal; -out_err: - kfree(journal->j_wbuf); - kfree(journal); - return NULL; -} - -/* - * 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 int first, last; - - first = be32_to_cpu(sb->s_first); - last = be32_to_cpu(sb->s_maxlen); - if (first + JFS_MIN_JOURNAL_BLOCKS > last + 1) { - printk(KERN_ERR "JBD: Journal too short (blocks %u-%u).\n", - first, last); - journal_fail_superblock(journal); - return -EINVAL; - } - - journal->j_first = first; - journal->j_last = last; - - journal->j_head = first; - journal->j_tail = first; - journal->j_free = last - 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 = journal->j_maxlen / 4; - - /* - * 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 JFS_FLUSHED. This avoids - * attempting a write to a potential-readonly device. - */ - if (sb->s_start == 0) { - jbd_debug(1,"JBD: Skipping superblock update on recovered sb " - "(start %u, seq %d, errno %d)\n", - journal->j_tail, journal->j_tail_sequence, - journal->j_errno); - journal->j_flags |= JFS_FLUSHED; - } else { - /* Lock here to make assertions happy... */ - mutex_lock(&journal->j_checkpoint_mutex); - /* - * Update log tail information. We use WRITE_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. - */ - journal_update_sb_log_tail(journal, - journal->j_tail_sequence, - journal->j_tail, - WRITE_FUA); - mutex_unlock(&journal->j_checkpoint_mutex); - } - return journal_start_thread(journal); -} - -/** - * int journal_create() - Initialise the new journal file - * @journal: Journal to create. This structure must have been initialised - * - * Given a journal_t structure which tells us which disk blocks we can - * use, create a new journal superblock and initialise all of the - * journal fields from scratch. - **/ -int journal_create(journal_t *journal) -{ - unsigned int blocknr; - struct buffer_head *bh; - journal_superblock_t *sb; - int i, err; - - if (journal->j_maxlen < JFS_MIN_JOURNAL_BLOCKS) { - printk (KERN_ERR "Journal length (%d blocks) too short.\n", - journal->j_maxlen); - journal_fail_superblock(journal); - return -EINVAL; - } - - if (journal->j_inode == NULL) { - /* - * We don't know what block to start at! - */ - printk(KERN_EMERG - "%s: creation of journal on external device!\n", - __func__); - BUG(); - } - - /* Zero out the entire journal on disk. We cannot afford to - have any blocks on disk beginning with JFS_MAGIC_NUMBER. */ - jbd_debug(1, "JBD: Zeroing out journal blocks...\n"); - for (i = 0; i < journal->j_maxlen; i++) { - err = journal_bmap(journal, i, &blocknr); - if (err) - return err; - bh = __getblk(journal->j_dev, blocknr, journal->j_blocksize); - if (unlikely(!bh)) - return -ENOMEM; - lock_buffer(bh); - memset (bh->b_data, 0, journal->j_blocksize); - BUFFER_TRACE(bh, "marking dirty"); - mark_buffer_dirty(bh); - BUFFER_TRACE(bh, "marking uptodate"); - set_buffer_uptodate(bh); - unlock_buffer(bh); - __brelse(bh); - } - - sync_blockdev(journal->j_dev); - jbd_debug(1, "JBD: journal cleared.\n"); - - /* OK, fill in the initial static fields in the new superblock */ - sb = journal->j_superblock; - - sb->s_header.h_magic = cpu_to_be32(JFS_MAGIC_NUMBER); - sb->s_header.h_blocktype = cpu_to_be32(JFS_SUPERBLOCK_V2); - - sb->s_blocksize = cpu_to_be32(journal->j_blocksize); - sb->s_maxlen = cpu_to_be32(journal->j_maxlen); - sb->s_first = cpu_to_be32(1); - - journal->j_transaction_sequence = 1; - - journal->j_flags &= ~JFS_ABORT; - journal->j_format_version = 2; - - return journal_reset(journal); -} - -static void journal_write_superblock(journal_t *journal, int write_op) -{ - struct buffer_head *bh = journal->j_sb_buffer; - int ret; - - trace_journal_write_superblock(journal, write_op); - if (!(journal->j_flags & JFS_BARRIER)) - write_op &= ~(REQ_FUA | REQ_FLUSH); - lock_buffer(bh); - if (buffer_write_io_error(bh)) { - char b[BDEVNAME_SIZE]; - /* - * 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 "JBD: previous I/O error detected " - "for journal superblock update for %s.\n", - journal_dev_name(journal, b)); - clear_buffer_write_io_error(bh); - set_buffer_uptodate(bh); - } - - get_bh(bh); - bh->b_end_io = end_buffer_write_sync; - ret = submit_bh(write_op, 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) { - char b[BDEVNAME_SIZE]; - printk(KERN_ERR "JBD: Error %d detected " - "when updating journal superblock for %s.\n", - ret, journal_dev_name(journal, b)); - } -} - -/** - * 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. - */ -void journal_update_sb_log_tail(journal_t *journal, tid_t tail_tid, - unsigned int tail_block, int write_op) -{ - journal_superblock_t *sb = journal->j_superblock; - - BUG_ON(!mutex_is_locked(&journal->j_checkpoint_mutex)); - jbd_debug(1,"JBD: updating superblock (start %u, seq %u)\n", - tail_block, tail_tid); - - sb->s_sequence = cpu_to_be32(tail_tid); - sb->s_start = cpu_to_be32(tail_block); - - journal_write_superblock(journal, write_op); - - /* Log is no longer empty */ - spin_lock(&journal->j_state_lock); - WARN_ON(!sb->s_sequence); - journal->j_flags &= ~JFS_FLUSHED; - spin_unlock(&journal->j_state_lock); -} - -/** - * mark_journal_empty() - Mark on disk journal as empty. - * @journal: The journal to update. - * - * 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 mark_journal_empty(journal_t *journal) -{ - journal_superblock_t *sb = journal->j_superblock; - - BUG_ON(!mutex_is_locked(&journal->j_checkpoint_mutex)); - spin_lock(&journal->j_state_lock); - /* Is it already empty? */ - if (sb->s_start == 0) { - spin_unlock(&journal->j_state_lock); - return; - } - jbd_debug(1, "JBD: Marking journal as empty (seq %d)\n", - journal->j_tail_sequence); - - sb->s_sequence = cpu_to_be32(journal->j_tail_sequence); - sb->s_start = cpu_to_be32(0); - spin_unlock(&journal->j_state_lock); - - journal_write_superblock(journal, WRITE_FUA); - - spin_lock(&journal->j_state_lock); - /* Log is empty */ - journal->j_flags |= JFS_FLUSHED; - spin_unlock(&journal->j_state_lock); -} - -/** - * 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. - */ -static void journal_update_sb_errno(journal_t *journal) -{ - journal_superblock_t *sb = journal->j_superblock; - - spin_lock(&journal->j_state_lock); - jbd_debug(1, "JBD: updating superblock error (errno %d)\n", - journal->j_errno); - sb->s_errno = cpu_to_be32(journal->j_errno); - spin_unlock(&journal->j_state_lock); - - journal_write_superblock(journal, WRITE_SYNC); -} - -/* - * 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(READ, 1, &bh); - wait_on_buffer(bh); - if (!buffer_uptodate(bh)) { - printk (KERN_ERR - "JBD: IO error reading journal superblock\n"); - goto out; - } - } - - sb = journal->j_superblock; - - err = -EINVAL; - - if (sb->s_header.h_magic != cpu_to_be32(JFS_MAGIC_NUMBER) || - sb->s_blocksize != cpu_to_be32(journal->j_blocksize)) { - printk(KERN_WARNING "JBD: no valid journal superblock found\n"); - goto out; - } - - switch(be32_to_cpu(sb->s_header.h_blocktype)) { - case JFS_SUPERBLOCK_V1: - journal->j_format_version = 1; - break; - case JFS_SUPERBLOCK_V2: - journal->j_format_version = 2; - break; - default: - printk(KERN_WARNING "JBD: unrecognised superblock format ID\n"); - goto out; - } - - if (be32_to_cpu(sb->s_maxlen) < journal->j_maxlen) - journal->j_maxlen = be32_to_cpu(sb->s_maxlen); - else if (be32_to_cpu(sb->s_maxlen) > journal->j_maxlen) { - printk (KERN_WARNING "JBD: journal file too short\n"); - goto out; - } - - if (be32_to_cpu(sb->s_first) == 0 || - be32_to_cpu(sb->s_first) >= journal->j_maxlen) { - printk(KERN_WARNING - "JBD: Invalid start block of journal: %u\n", - be32_to_cpu(sb->s_first)); - goto out; - } - - 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; - - 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_last = be32_to_cpu(sb->s_maxlen); - journal->j_errno = be32_to_cpu(sb->s_errno); - - return 0; -} - - -/** - * int 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 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(JFS_KNOWN_ROCOMPAT_FEATURES)) || - (sb->s_feature_incompat & - ~cpu_to_be32(JFS_KNOWN_INCOMPAT_FEATURES))) { - printk (KERN_WARNING - "JBD: Unrecognised features on journal\n"); - return -EINVAL; - } - } - - /* Let the recovery code check whether it needs to recover any - * data from the journal. */ - if (journal_recover(journal)) - goto recovery_error; - - /* 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 &= ~JFS_ABORT; - journal->j_flags |= JFS_LOADED; - return 0; - -recovery_error: - printk (KERN_WARNING "JBD: recovery failed\n"); - return -EIO; -} - -/** - * void 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 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) - journal_commit_transaction(journal); - - /* Force any old transactions to disk */ - - /* We cannot race with anybody but must keep assertions happy */ - mutex_lock(&journal->j_checkpoint_mutex); - /* Totally anal locking here... */ - spin_lock(&journal->j_list_lock); - while (journal->j_checkpoint_transactions != NULL) { - spin_unlock(&journal->j_list_lock); - log_do_checkpoint(journal); - 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)) { - journal->j_tail_sequence = - ++journal->j_transaction_sequence; - mark_journal_empty(journal); - } else - err = -EIO; - brelse(journal->j_sb_buffer); - } - mutex_unlock(&journal->j_checkpoint_mutex); - - iput(journal->j_inode); - if (journal->j_revoke) - journal_destroy_revoke(journal); - kfree(journal->j_wbuf); - kfree(journal); - - return err; -} - - -/** - *int 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 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; - 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; -} - -/** - * int 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 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 & JFS_KNOWN_COMPAT_FEATURES) == compat && - (ro & JFS_KNOWN_ROCOMPAT_FEATURES) == ro && - (incompat & JFS_KNOWN_INCOMPAT_FEATURES) == incompat) - return 1; - - return 0; -} - -/** - * int 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 journal_set_features (journal_t *journal, unsigned long compat, - unsigned long ro, unsigned long incompat) -{ - journal_superblock_t *sb; - - if (journal_check_used_features(journal, compat, ro, incompat)) - return 1; - - if (!journal_check_available_features(journal, compat, ro, incompat)) - return 0; - - jbd_debug(1, "Setting new 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); - - return 1; -} - - -/** - * int journal_update_format () - Update on-disk journal structure. - * @journal: Journal to act on. - * - * Given an initialised but unloaded journal struct, poke about in the - * on-disk structure to update it to the most recent supported version. - */ -int journal_update_format (journal_t *journal) -{ - journal_superblock_t *sb; - int err; - - err = journal_get_superblock(journal); - if (err) - return err; - - sb = journal->j_superblock; - - switch (be32_to_cpu(sb->s_header.h_blocktype)) { - case JFS_SUPERBLOCK_V2: - return 0; - case JFS_SUPERBLOCK_V1: - return journal_convert_superblock_v1(journal, sb); - default: - break; - } - return -EINVAL; -} - -static int journal_convert_superblock_v1(journal_t *journal, - journal_superblock_t *sb) -{ - int offset, blocksize; - struct buffer_head *bh; - - printk(KERN_WARNING - "JBD: Converting superblock from version 1 to 2.\n"); - - /* Pre-initialise new fields to zero */ - offset = ((char *) &(sb->s_feature_compat)) - ((char *) sb); - blocksize = be32_to_cpu(sb->s_blocksize); - memset(&sb->s_feature_compat, 0, blocksize-offset); - - sb->s_nr_users = cpu_to_be32(1); - sb->s_header.h_blocktype = cpu_to_be32(JFS_SUPERBLOCK_V2); - journal->j_format_version = 2; - - bh = journal->j_sb_buffer; - BUFFER_TRACE(bh, "marking dirty"); - mark_buffer_dirty(bh); - sync_dirty_buffer(bh); - return 0; -} - - -/** - * int 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 journal_flush(journal_t *journal) -{ - int err = 0; - transaction_t *transaction = NULL; - - spin_lock(&journal->j_state_lock); - - /* Force everything buffered to the log... */ - if (journal->j_running_transaction) { - transaction = journal->j_running_transaction; - __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; - - spin_unlock(&journal->j_state_lock); - log_wait_commit(journal, tid); - } else { - spin_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(&journal->j_checkpoint_mutex); - err = 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(&journal->j_checkpoint_mutex); - cleanup_journal_tail(journal); - - /* 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. */ - mark_journal_empty(journal); - mutex_unlock(&journal->j_checkpoint_mutex); - spin_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); - spin_unlock(&journal->j_state_lock); - return 0; -} - -/** - * int 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 journal_load(). - * - * If 'write' is non-zero, then we wipe out the journal on disk; otherwise - * we merely suppress recovery. - */ - -int journal_wipe(journal_t *journal, int write) -{ - int err = 0; - - J_ASSERT (!(journal->j_flags & JFS_LOADED)); - - err = load_superblock(journal); - if (err) - return err; - - if (!journal->j_tail) - goto no_recovery; - - printk (KERN_WARNING "JBD: %s recovery information on journal\n", - write ? "Clearing" : "Ignoring"); - - err = journal_skip_recovery(journal); - if (write) { - /* Lock to make assertions happy... */ - mutex_lock(&journal->j_checkpoint_mutex); - mark_journal_empty(journal); - mutex_unlock(&journal->j_checkpoint_mutex); - } - - no_recovery: - return err; -} - -/* - * journal_dev_name: format a character string to describe on what - * device this journal is present. - */ - -static const char *journal_dev_name(journal_t *journal, char *buffer) -{ - struct block_device *bdev; - - if (journal->j_inode) - bdev = journal->j_inode->i_sb->s_bdev; - else - bdev = journal->j_dev; - - return bdevname(bdev, buffer); -} - -/* - * Journal abort has very specific semantics, which we describe - * for journal abort. - * - * Two internal function, which provide abort to te jbd layer - * itself are here. - */ - -/* - * Quick version for internal journal use (doesn't lock the journal). - * Aborts hard --- we mark the abort as occurred, but do _nothing_ else, - * and don't attempt to make any other journal updates. - */ -static void __journal_abort_hard(journal_t *journal) -{ - transaction_t *transaction; - char b[BDEVNAME_SIZE]; - - if (journal->j_flags & JFS_ABORT) - return; - - printk(KERN_ERR "Aborting journal on device %s.\n", - journal_dev_name(journal, b)); - - spin_lock(&journal->j_state_lock); - journal->j_flags |= JFS_ABORT; - transaction = journal->j_running_transaction; - if (transaction) - __log_start_commit(journal, transaction->t_tid); - spin_unlock(&journal->j_state_lock); -} - -/* Soft abort: record the abort error status in the journal superblock, - * but don't do any other IO. */ -static void __journal_abort_soft (journal_t *journal, int errno) -{ - if (journal->j_flags & JFS_ABORT) - return; - - if (!journal->j_errno) - journal->j_errno = errno; - - __journal_abort_hard(journal); - - if (errno) - journal_update_sb_errno(journal); -} - -/** - * void 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 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 - * 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 journal_stop, which will receive the -EIO error. - * - * Finally, the 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. - * - * Errors which originate from within the journaling layer will NOT - * supply an errno; a null errno implies that absolutely no further - * writes are done to the journal (unless there are any already in - * progress). - * - */ - -void journal_abort(journal_t *journal, int errno) -{ - __journal_abort_soft(journal, errno); -} - -/** - * int journal_errno () - returns the journal's error state. - * @journal: journal to examine. - * - * This is the errno numbet set with 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 journal_errno(journal_t *journal) -{ - int err; - - spin_lock(&journal->j_state_lock); - if (journal->j_flags & JFS_ABORT) - err = -EROFS; - else - err = journal->j_errno; - spin_unlock(&journal->j_state_lock); - return err; -} - -/** - * int 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 journal_clear_err(journal_t *journal) -{ - int err = 0; - - spin_lock(&journal->j_state_lock); - if (journal->j_flags & JFS_ABORT) - err = -EROFS; - else - journal->j_errno = 0; - spin_unlock(&journal->j_state_lock); - return err; -} - -/** - * void 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 journal_ack_err(journal_t *journal) -{ - spin_lock(&journal->j_state_lock); - if (journal->j_errno) - journal->j_flags |= JFS_ACK_ERR; - spin_unlock(&journal->j_state_lock); -} - -int journal_blocks_per_page(struct inode *inode) -{ - return 1 << (PAGE_CACHE_SHIFT - inode->i_sb->s_blocksize_bits); -} - -/* - * Journal_head storage management - */ -static struct kmem_cache *journal_head_cache; -#ifdef CONFIG_JBD_DEBUG -static atomic_t nr_journal_heads = ATOMIC_INIT(0); -#endif - -static int journal_init_journal_head_cache(void) -{ - int retval; - - J_ASSERT(journal_head_cache == NULL); - journal_head_cache = kmem_cache_create("journal_head", - sizeof(struct journal_head), - 0, /* offset */ - SLAB_TEMPORARY, /* flags */ - NULL); /* ctor */ - retval = 0; - if (!journal_head_cache) { - retval = -ENOMEM; - printk(KERN_EMERG "JBD: no memory for journal_head cache\n"); - } - return retval; -} - -static void journal_destroy_journal_head_cache(void) -{ - if (journal_head_cache) { - kmem_cache_destroy(journal_head_cache); - journal_head_cache = NULL; - } -} - -/* - * journal_head splicing and dicing - */ -static struct journal_head *journal_alloc_journal_head(void) -{ - struct journal_head *ret; - -#ifdef CONFIG_JBD_DEBUG - atomic_inc(&nr_journal_heads); -#endif - ret = kmem_cache_zalloc(journal_head_cache, GFP_NOFS); - if (ret == NULL) { - jbd_debug(1, "out of memory for journal_head\n"); - printk_ratelimited(KERN_NOTICE "ENOMEM in %s, retrying.\n", - __func__); - - while (ret == NULL) { - yield(); - ret = kmem_cache_zalloc(journal_head_cache, GFP_NOFS); - } - } - return ret; -} - -static void journal_free_journal_head(struct journal_head *jh) -{ -#ifdef CONFIG_JBD_DEBUG - atomic_dec(&nr_journal_heads); - memset(jh, JBD_POISON_FREE, sizeof(*jh)); -#endif - kmem_cache_free(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, journal_add_journal_head elevates the - * journal_head's b_jcount refcount by one. The caller must call - * 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 = journal_add_journal_head(bh); - * ... - * (Get another reference for transaction) - * journal_grab_journal_head(bh); - * jh->b_transaction = xxx; - * (Put original reference) - * journal_put_journal_head(jh); - */ - -/* - * Give a buffer_head a journal_head. - * - * May sleep. - */ -struct journal_head *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 *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; -} - -static void __journal_remove_journal_head(struct buffer_head *bh) -{ - struct journal_head *jh = bh2jh(bh); - - J_ASSERT_JH(jh, jh->b_jcount >= 0); - 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"); - if (jh->b_frozen_data) { - printk(KERN_WARNING "%s: freeing b_frozen_data\n", __func__); - jbd_free(jh->b_frozen_data, bh->b_size); - } - if (jh->b_committed_data) { - printk(KERN_WARNING "%s: freeing b_committed_data\n", __func__); - jbd_free(jh->b_committed_data, bh->b_size); - } - bh->b_private = NULL; - jh->b_bh = NULL; /* debug, really */ - clear_buffer_jbd(bh); - 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 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); - __brelse(bh); - } else - jbd_unlock_bh_journal_head(bh); -} - -/* - * debugfs tunables - */ -#ifdef CONFIG_JBD_DEBUG - -u8 journal_enable_debug __read_mostly; -EXPORT_SYMBOL(journal_enable_debug); - -static struct dentry *jbd_debugfs_dir; -static struct dentry *jbd_debug; - -static void __init jbd_create_debugfs_entry(void) -{ - jbd_debugfs_dir = debugfs_create_dir("jbd", NULL); - if (jbd_debugfs_dir) - jbd_debug = debugfs_create_u8("jbd-debug", S_IRUGO | S_IWUSR, - jbd_debugfs_dir, - &journal_enable_debug); -} - -static void __exit jbd_remove_debugfs_entry(void) -{ - debugfs_remove(jbd_debug); - debugfs_remove(jbd_debugfs_dir); -} - -#else - -static inline void jbd_create_debugfs_entry(void) -{ -} - -static inline void jbd_remove_debugfs_entry(void) -{ -} - -#endif - -struct kmem_cache *jbd_handle_cache; - -static int __init journal_init_handle_cache(void) -{ - jbd_handle_cache = kmem_cache_create("journal_handle", - sizeof(handle_t), - 0, /* offset */ - SLAB_TEMPORARY, /* flags */ - NULL); /* ctor */ - if (jbd_handle_cache == NULL) { - printk(KERN_EMERG "JBD: failed to create handle cache\n"); - return -ENOMEM; - } - return 0; -} - -static void journal_destroy_handle_cache(void) -{ - if (jbd_handle_cache) - kmem_cache_destroy(jbd_handle_cache); -} - -/* - * Module startup and shutdown - */ - -static int __init journal_init_caches(void) -{ - int ret; - - ret = journal_init_revoke_caches(); - if (ret == 0) - ret = journal_init_journal_head_cache(); - if (ret == 0) - ret = journal_init_handle_cache(); - return ret; -} - -static void journal_destroy_caches(void) -{ - journal_destroy_revoke_caches(); - journal_destroy_journal_head_cache(); - journal_destroy_handle_cache(); -} - -static int __init journal_init(void) -{ - int ret; - - BUILD_BUG_ON(sizeof(struct journal_superblock_s) != 1024); - - ret = journal_init_caches(); - if (ret != 0) - journal_destroy_caches(); - jbd_create_debugfs_entry(); - return ret; -} - -static void __exit journal_exit(void) -{ -#ifdef CONFIG_JBD_DEBUG - int n = atomic_read(&nr_journal_heads); - if (n) - printk(KERN_ERR "JBD: leaked %d journal_heads!\n", n); -#endif - jbd_remove_debugfs_entry(); - journal_destroy_caches(); -} - -MODULE_LICENSE("GPL"); -module_init(journal_init); -module_exit(journal_exit); - |