| /* |
| * 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/smp_lock.h> |
| #include <linux/init.h> |
| #include <linux/mm.h> |
| #include <linux/suspend.h> |
| #include <linux/pagemap.h> |
| #include <linux/kthread.h> |
| #include <linux/poison.h> |
| #include <linux/proc_fs.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_update_superblock); |
| 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(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 int journal_create_jbd_slab(size_t slab_size); |
| |
| /* |
| * 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); |
| |
| /* 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); |
| refrigerator(); |
| 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 void journal_start_thread(journal_t *journal) |
| { |
| kthread_run(kjournald, journal, "kjournald"); |
| wait_event(journal->j_wait_done_commit, journal->j_task != 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 == 0); |
| 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 long 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); |
| |
| /* |
| * 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); |
| |
| /* |
| * 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, KM_USER0); |
| /* |
| * 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, KM_USER0); |
| |
| /* |
| * 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_slab_alloc(bh_in->b_size, GFP_NOFS); |
| jbd_lock_bh_state(bh_in); |
| if (jh_in->b_frozen_data) { |
| jbd_slab_free(tmp, bh_in->b_size); |
| goto repeat; |
| } |
| |
| jh_in->b_frozen_data = tmp; |
| mapped_data = kmap_atomic(new_page, KM_USER0); |
| memcpy(tmp, mapped_data + new_offset, jh2bh(jh_in)->b_size); |
| kunmap_atomic(mapped_data, KM_USER0); |
| |
| 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, KM_USER0); |
| *((unsigned int *)(mapped_data + new_offset)) = 0; |
| kunmap_atomic(mapped_data, KM_USER0); |
| } |
| |
| /* keep subsequent assertions sane */ |
| new_bh->b_state = 0; |
| init_buffer(new_bh, NULL, NULL); |
| atomic_set(&new_bh->b_count, 1); |
| jbd_unlock_bh_state(bh_in); |
| |
| new_jh = journal_add_journal_head(new_bh); /* This sleeps */ |
| |
| 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"); |
| journal_file_buffer(jh_in, transaction, BJ_Shadow); |
| 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 was started. |
| */ |
| int __log_start_commit(journal_t *journal, tid_t target) |
| { |
| /* |
| * Are we already doing a recent enough commit? |
| */ |
| if (!tid_geq(journal->j_commit_request, target)) { |
| /* |
| * We want a new commit: OK, mark the request and wakup 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; |
| } |
| 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 was started, 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; |
| |
| ret = __log_start_commit(journal, tid); |
| if (ret && ptid) |
| *ptid = tid; |
| } else if (journal->j_committing_transaction && ptid) { |
| /* |
| * If ext3_write_super() recently started a commit, then we |
| * have to wait for completion of that transaction |
| */ |
| *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_EMERG |
| "%s: error: j_commit_request=%d, tid=%d\n", |
| __FUNCTION__, journal->j_commit_request, tid); |
| } |
| spin_unlock(&journal->j_state_lock); |
| #endif |
| spin_lock(&journal->j_state_lock); |
| 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); |
| } |
| spin_unlock(&journal->j_state_lock); |
| |
| if (unlikely(is_journal_aborted(journal))) { |
| printk(KERN_EMERG "journal commit I/O error\n"); |
| err = -EIO; |
| } |
| return err; |
| } |
| |
| /* |
| * Log buffer allocation routines: |
| */ |
| |
| int journal_next_log_block(journal_t *journal, unsigned long *retp) |
| { |
| unsigned long 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 long blocknr, |
| unsigned long *retp) |
| { |
| int err = 0; |
| unsigned long 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 %lu on %s\n", |
| __FUNCTION__, |
| 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 long blocknr; |
| int err; |
| |
| err = journal_next_log_block(journal, &blocknr); |
| |
| if (err) |
| return NULL; |
| |
| bh = __getblk(journal->j_dev, blocknr, journal->j_blocksize); |
| 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 = jbd_kmalloc(sizeof(*journal), GFP_KERNEL); |
| if (!journal) |
| goto fail; |
| memset(journal, 0, sizeof(*journal)); |
| |
| 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_barrier); |
| 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 an 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: Cant allocate bhs for commit thread\n", |
| __FUNCTION__); |
| kfree(journal); |
| journal = NULL; |
| goto out; |
| } |
| 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); |
| J_ASSERT(bh != NULL); |
| journal->j_sb_buffer = bh; |
| journal->j_superblock = (journal_superblock_t *)bh->b_data; |
| out: |
| return journal; |
| } |
| |
| /** |
| * 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 long 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: Cant allocate bhs for commit thread\n", |
| __FUNCTION__); |
| kfree(journal); |
| return NULL; |
| } |
| |
| err = journal_bmap(journal, 0, &blocknr); |
| /* If that failed, give up */ |
| if (err) { |
| printk(KERN_ERR "%s: Cannnot locate journal superblock\n", |
| __FUNCTION__); |
| kfree(journal); |
| return NULL; |
| } |
| |
| bh = __getblk(journal->j_dev, blocknr, journal->j_blocksize); |
| J_ASSERT(bh != NULL); |
| journal->j_sb_buffer = bh; |
| journal->j_superblock = (journal_superblock_t *)bh->b_data; |
| |
| 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 first, last; |
| |
| first = be32_to_cpu(sb->s_first); |
| last = be32_to_cpu(sb->s_maxlen); |
| |
| 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; |
| |
| /* Add the dynamic fields and write it to disk. */ |
| journal_update_superblock(journal, 1); |
| journal_start_thread(journal); |
| return 0; |
| } |
| |
| /** |
| * 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 long 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", |
| __FUNCTION__); |
| 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); |
| 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); |
| } |
| |
| /** |
| * void journal_update_superblock() - Update journal sb on disk. |
| * @journal: The journal to update. |
| * @wait: Set to '0' if you don't want to wait for IO completion. |
| * |
| * Update a journal's dynamic superblock fields and write it to disk, |
| * optionally waiting for the IO to complete. |
| */ |
| void journal_update_superblock(journal_t *journal, int wait) |
| { |
| journal_superblock_t *sb = journal->j_superblock; |
| struct buffer_head *bh = journal->j_sb_buffer; |
| |
| /* |
| * As a special case, if the on-disk copy is already marked as needing |
| * no recovery (s_start == 0) and there are no outstanding transactions |
| * in the filesystem, 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 && journal->j_tail_sequence == |
| journal->j_transaction_sequence) { |
| jbd_debug(1,"JBD: Skipping superblock update on recovered sb " |
| "(start %ld, seq %d, errno %d)\n", |
| journal->j_tail, journal->j_tail_sequence, |
| journal->j_errno); |
| goto out; |
| } |
| |
| spin_lock(&journal->j_state_lock); |
| jbd_debug(1,"JBD: updating superblock (start %ld, seq %d, errno %d)\n", |
| journal->j_tail, journal->j_tail_sequence, journal->j_errno); |
| |
| sb->s_sequence = cpu_to_be32(journal->j_tail_sequence); |
| sb->s_start = cpu_to_be32(journal->j_tail); |
| sb->s_errno = cpu_to_be32(journal->j_errno); |
| spin_unlock(&journal->j_state_lock); |
| |
| BUFFER_TRACE(bh, "marking dirty"); |
| mark_buffer_dirty(bh); |
| if (wait) |
| sync_dirty_buffer(bh); |
| else |
| ll_rw_block(SWRITE, 1, &bh); |
| |
| out: |
| /* If we have just flushed the log (by marking s_start==0), then |
| * any future commit will have to be careful to update the |
| * superblock again to re-record the true start of the log. */ |
| |
| spin_lock(&journal->j_state_lock); |
| if (sb->s_start) |
| journal->j_flags &= ~JFS_FLUSHED; |
| else |
| journal->j_flags |= JFS_FLUSHED; |
| spin_unlock(&journal->j_state_lock); |
| } |
| |
| /* |
| * 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; |
| } |
| |
| 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; |
| } |
| } |
| |
| /* |
| * Create a slab for this blocksize |
| */ |
| err = journal_create_jbd_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 (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. |
| */ |
| void journal_destroy(journal_t *journal) |
| { |
| /* 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 */ |
| |
| /* 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); |
| |
| /* We can now mark the journal as empty. */ |
| journal->j_tail = 0; |
| journal->j_tail_sequence = ++journal->j_transaction_sequence; |
| if (journal->j_sb_buffer) { |
| journal_update_superblock(journal, 1); |
| brelse(journal->j_sb_buffer); |
| } |
| |
| if (journal->j_inode) |
| iput(journal->j_inode); |
| if (journal->j_revoke) |
| journal_destroy_revoke(journal); |
| kfree(journal->j_wbuf); |
| kfree(journal); |
| } |
| |
| |
| /** |
| *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) |
| { |
| journal_superblock_t *sb; |
| |
| if (!compat && !ro && !incompat) |
| return 1; |
| |
| sb = journal->j_superblock; |
| |
| /* 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; |
| unsigned long old_tail; |
| |
| 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); |
| err = log_do_checkpoint(journal); |
| spin_lock(&journal->j_list_lock); |
| } |
| spin_unlock(&journal->j_list_lock); |
| 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. */ |
| spin_lock(&journal->j_state_lock); |
| old_tail = journal->j_tail; |
| journal->j_tail = 0; |
| spin_unlock(&journal->j_state_lock); |
| journal_update_superblock(journal, 1); |
| spin_lock(&journal->j_state_lock); |
| journal->j_tail = old_tail; |
| |
| 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 err; |
| } |
| |
| /** |
| * 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) |
| { |
| journal_superblock_t *sb; |
| int err = 0; |
| |
| J_ASSERT (!(journal->j_flags & JFS_LOADED)); |
| |
| err = load_superblock(journal); |
| if (err) |
| return err; |
| |
| sb = journal->j_superblock; |
| |
| 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) |
| journal_update_superblock(journal, 1); |
| |
| 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. |
| */ |
| 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_superblock(journal, 1); |
| } |
| |
| /** |
| * 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); |
| } |
| |
| /* |
| * Simple support for retrying memory allocations. Introduced to help to |
| * debug different VM deadlock avoidance strategies. |
| */ |
| void * __jbd_kmalloc (const char *where, size_t size, gfp_t flags, int retry) |
| { |
| return kmalloc(size, flags | (retry ? __GFP_NOFAIL : 0)); |
| } |
| |
| /* |
| * jbd slab management: create 1k, 2k, 4k, 8k slabs as needed |
| * and allocate frozen and commit buffers from these slabs. |
| * |
| * Reason for doing this is to avoid, SLAB_DEBUG - since it could |
| * cause bh to cross page boundary. |
| */ |
| |
| #define JBD_MAX_SLABS 5 |
| #define JBD_SLAB_INDEX(size) (size >> 11) |
| |
| static struct kmem_cache *jbd_slab[JBD_MAX_SLABS]; |
| static const char *jbd_slab_names[JBD_MAX_SLABS] = { |
| "jbd_1k", "jbd_2k", "jbd_4k", NULL, "jbd_8k" |
| }; |
| |
| static void journal_destroy_jbd_slabs(void) |
| { |
| int i; |
| |
| for (i = 0; i < JBD_MAX_SLABS; i++) { |
| if (jbd_slab[i]) |
| kmem_cache_destroy(jbd_slab[i]); |
| jbd_slab[i] = NULL; |
| } |
| } |
| |
| static int journal_create_jbd_slab(size_t slab_size) |
| { |
| int i = JBD_SLAB_INDEX(slab_size); |
| |
| BUG_ON(i >= JBD_MAX_SLABS); |
| |
| /* |
| * Check if we already have a slab created for this size |
| */ |
| if (jbd_slab[i]) |
| return 0; |
| |
| /* |
| * Create a slab and force alignment to be same as slabsize - |
| * this will make sure that allocations won't cross the page |
| * boundary. |
| */ |
| jbd_slab[i] = kmem_cache_create(jbd_slab_names[i], |
| slab_size, slab_size, 0, NULL, NULL); |
| if (!jbd_slab[i]) { |
| printk(KERN_EMERG "JBD: no memory for jbd_slab cache\n"); |
| return -ENOMEM; |
| } |
| return 0; |
| } |
| |
| void * jbd_slab_alloc(size_t size, gfp_t flags) |
| { |
| int idx; |
| |
| idx = JBD_SLAB_INDEX(size); |
| BUG_ON(jbd_slab[idx] == NULL); |
| return kmem_cache_alloc(jbd_slab[idx], flags | __GFP_NOFAIL); |
| } |
| |
| void jbd_slab_free(void *ptr, size_t size) |
| { |
| int idx; |
| |
| idx = JBD_SLAB_INDEX(size); |
| BUG_ON(jbd_slab[idx] == NULL); |
| kmem_cache_free(jbd_slab[idx], ptr); |
| } |
| |
| /* |
| * 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 == 0); |
| journal_head_cache = kmem_cache_create("journal_head", |
| sizeof(struct journal_head), |
| 0, /* offset */ |
| 0, /* flags */ |
| NULL, /* ctor */ |
| NULL); /* dtor */ |
| retval = 0; |
| if (journal_head_cache == 0) { |
| retval = -ENOMEM; |
| printk(KERN_EMERG "JBD: no memory for journal_head cache\n"); |
| } |
| return retval; |
| } |
| |
| static void journal_destroy_journal_head_cache(void) |
| { |
| J_ASSERT(journal_head_cache != NULL); |
| 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; |
| static unsigned long last_warning; |
| |
| #ifdef CONFIG_JBD_DEBUG |
| atomic_inc(&nr_journal_heads); |
| #endif |
| ret = kmem_cache_alloc(journal_head_cache, GFP_NOFS); |
| if (ret == 0) { |
| jbd_debug(1, "out of memory for journal_head\n"); |
| if (time_after(jiffies, last_warning + 5*HZ)) { |
| printk(KERN_NOTICE "ENOMEM in %s, retrying.\n", |
| __FUNCTION__); |
| last_warning = jiffies; |
| } |
| while (ret == 0) { |
| yield(); |
| ret = kmem_cache_alloc(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 may be detached from its buffer_head when the journal_head's |
| * b_transaction, b_cp_transaction and b_next_transaction pointers are NULL. |
| * Various places in JBD call journal_remove_journal_head() to indicate that the |
| * journal_head can be dropped if needed. |
| * |
| * 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); |
| * ... |
| * jh->b_transaction = xxx; |
| * journal_put_journal_head(jh); |
| * |
| * Now, the journal_head's b_jcount is zero, but it is safe from being released |
| * because it has a non-zero b_transaction. |
| */ |
| |
| /* |
| * Give a buffer_head a journal_head. |
| * |
| * Doesn't need the journal lock. |
| * 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(); |
| memset(new_jh, 0, sizeof(*new_jh)); |
| } |
| |
| 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); |
| |
| get_bh(bh); |
| if (jh->b_jcount == 0) { |
| if (jh->b_transaction == NULL && |
| jh->b_next_transaction == NULL && |
| 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", |
| __FUNCTION__); |
| jbd_slab_free(jh->b_frozen_data, bh->b_size); |
| } |
| if (jh->b_committed_data) { |
| printk(KERN_WARNING "%s: freeing " |
| "b_committed_data\n", |
| __FUNCTION__); |
| jbd_slab_free(jh->b_committed_data, bh->b_size); |
| } |
| bh->b_private = NULL; |
| jh->b_bh = NULL; /* debug, really */ |
| clear_buffer_jbd(bh); |
| __brelse(bh); |
| journal_free_journal_head(jh); |
| } else { |
| BUFFER_TRACE(bh, "journal_head was locked"); |
| } |
| } |
| } |
| |
| /* |
| * journal_remove_journal_head(): if the buffer isn't attached to a transaction |
| * and has a zero b_jcount then remove and release its journal_head. If we did |
| * see that the buffer is not used by any transaction we also "logically" |
| * decrement ->b_count. |
| * |
| * We in fact take an additional increment on ->b_count as a convenience, |
| * because the caller usually wants to do additional things with the bh |
| * after calling here. |
| * The caller of journal_remove_journal_head() *must* run __brelse(bh) at some |
| * time. Once the caller has run __brelse(), the buffer is eligible for |
| * reaping by try_to_free_buffers(). |
| */ |
| void journal_remove_journal_head(struct buffer_head *bh) |
| { |
| jbd_lock_bh_journal_head(bh); |
| __journal_remove_journal_head(bh); |
| jbd_unlock_bh_journal_head(bh); |
| } |
| |
| /* |
| * Drop a reference on the passed journal_head. If it fell to zero then try to |
| * 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 && !jh->b_transaction) { |
| __journal_remove_journal_head(bh); |
| __brelse(bh); |
| } |
| jbd_unlock_bh_journal_head(bh); |
| } |
| |
| /* |
| * /proc tunables |
| */ |
| #if defined(CONFIG_JBD_DEBUG) |
| int journal_enable_debug; |
| EXPORT_SYMBOL(journal_enable_debug); |
| #endif |
| |
| #if defined(CONFIG_JBD_DEBUG) && defined(CONFIG_PROC_FS) |
| |
| static struct proc_dir_entry *proc_jbd_debug; |
| |
| static int read_jbd_debug(char *page, char **start, off_t off, |
| int count, int *eof, void *data) |
| { |
| int ret; |
| |
| ret = sprintf(page + off, "%d\n", journal_enable_debug); |
| *eof = 1; |
| return ret; |
| } |
| |
| static int write_jbd_debug(struct file *file, const char __user *buffer, |
| unsigned long count, void *data) |
| { |
| char buf[32]; |
| |
| if (count > ARRAY_SIZE(buf) - 1) |
| count = ARRAY_SIZE(buf) - 1; |
| if (copy_from_user(buf, buffer, count)) |
| return -EFAULT; |
| buf[ARRAY_SIZE(buf) - 1] = '\0'; |
| journal_enable_debug = simple_strtoul(buf, NULL, 10); |
| return count; |
| } |
| |
| #define JBD_PROC_NAME "sys/fs/jbd-debug" |
| |
| static void __init create_jbd_proc_entry(void) |
| { |
| proc_jbd_debug = create_proc_entry(JBD_PROC_NAME, 0644, NULL); |
| if (proc_jbd_debug) { |
| /* Why is this so hard? */ |
| proc_jbd_debug->read_proc = read_jbd_debug; |
| proc_jbd_debug->write_proc = write_jbd_debug; |
| } |
| } |
| |
| static void __exit remove_jbd_proc_entry(void) |
| { |
| if (proc_jbd_debug) |
| remove_proc_entry(JBD_PROC_NAME, NULL); |
| } |
| |
| #else |
| |
| #define create_jbd_proc_entry() do {} while (0) |
| #define remove_jbd_proc_entry() do {} while (0) |
| |
| #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 */ |
| 0, /* flags */ |
| NULL, /* ctor */ |
| NULL); /* dtor */ |
| 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(); |
| journal_destroy_jbd_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) |
| journal_destroy_caches(); |
| create_jbd_proc_entry(); |
| return ret; |
| } |
| |
| static void __exit journal_exit(void) |
| { |
| #ifdef CONFIG_JBD_DEBUG |
| int n = atomic_read(&nr_journal_heads); |
| if (n) |
| printk(KERN_EMERG "JBD: leaked %d journal_heads!\n", n); |
| #endif |
| remove_jbd_proc_entry(); |
| journal_destroy_caches(); |
| } |
| |
| MODULE_LICENSE("GPL"); |
| module_init(journal_init); |
| module_exit(journal_exit); |
| |