/* * linux/fs/journal.c * * Written by Stephen C. Tweedie , 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 #include #include #include #include #include #include #include #include #include #include #include #include #include #include "hfsplus_jbd.h" #include "hfsplus_fs.h" EXPORT_SYMBOL(hfsplus_jbd_start); EXPORT_SYMBOL(hfsplus_jbd_restart); EXPORT_SYMBOL(hfsplus_jbd_extend); EXPORT_SYMBOL(hfsplus_jbd_stop); EXPORT_SYMBOL(hfsplus_jbd_lock_updates); EXPORT_SYMBOL(hfsplus_jbd_unlock_updates); EXPORT_SYMBOL(hfsplus_jbd_get_write_access); EXPORT_SYMBOL(hfsplus_jbd_get_create_access); EXPORT_SYMBOL(hfsplus_jbd_get_undo_access); EXPORT_SYMBOL(hfsplus_jbd_dirty_data); EXPORT_SYMBOL(hfsplus_jbd_dirty_metadata); EXPORT_SYMBOL(hfsplus_jbd_release_buffer); EXPORT_SYMBOL(hfsplus_jbd_forget); #if 0 EXPORT_SYMBOL(hfsplus_jbd_sync_buffer); #endif EXPORT_SYMBOL(hfsplus_jbd_flush); EXPORT_SYMBOL(hfsplus_jbd_revoke); EXPORT_SYMBOL(hfsplus_jbd_init_dev); EXPORT_SYMBOL(hfsplus_jbd_init_inode); EXPORT_SYMBOL(hfsplus_jbd_update_format); EXPORT_SYMBOL(hfsplus_jbd_check_used_features); EXPORT_SYMBOL(hfsplus_jbd_check_available_features); EXPORT_SYMBOL(hfsplus_jbd_set_features); EXPORT_SYMBOL(hfsplus_jbd_create); EXPORT_SYMBOL(hfsplus_jbd_load); EXPORT_SYMBOL(hfsplus_jbd_destroy); EXPORT_SYMBOL(hfsplus_jbd_update_superblock); EXPORT_SYMBOL(hfsplus_jbd_abort); EXPORT_SYMBOL(hfsplus_jbd_errno); EXPORT_SYMBOL(hfsplus_jbd_ack_err); EXPORT_SYMBOL(hfsplus_jbd_clear_err); EXPORT_SYMBOL(hfsplus_jbd_log_wait_commit); EXPORT_SYMBOL(hfsplus_jbd_start_commit); EXPORT_SYMBOL(hfsplus_jbd_force_commit_nested); EXPORT_SYMBOL(hfsplus_jbd_wipe); EXPORT_SYMBOL(hfsplus_jbd_blocks_per_page); EXPORT_SYMBOL(hfsplus_jbd_invalidatepage); EXPORT_SYMBOL(hfsplus_jbd_try_to_free_buffers); EXPORT_SYMBOL(hfsplus_jbd_force_commit); static int hfsplus_jbd_convert_superblock_v1(hfsplus_jbd_t *, hfsplus_jbd_superblock_t *); static void __hfsplus_jbd_abort_soft (hfsplus_jbd_t *journal, int errno); /* * 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); } /* * hfsplus_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 hfsplus_kjournald(void *arg) { hfsplus_jbd_t *journal = (hfsplus_jbd_t *) arg; hfsplus_transaction_t *transaction; struct timer_list timer; daemonize("hfsplus_kjournald"); /* Set up an interval timer which can be used to trigger a commit wakeup after the commit interval expires */ init_timer(&timer); timer.data = (unsigned long) current; timer.function = commit_timeout; journal->j_commit_timer = &timer; /* Record that the journal thread is running */ journal->j_task = current; wake_up(&journal->j_wait_done_commit); printk(KERN_INFO "hfsplus_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; hfsplus_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) { hfsplus_jbd_debug(1, "OK, requests differ\n"); spin_unlock(&journal->j_state_lock); del_timer_sync(journal->j_commit_timer); hfsplus_jbd_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. */ hfsplus_jbd_debug(1, "Now suspending hfsplus_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); } hfsplus_jbd_debug(1, "hfsplus_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; hfsplus_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); hfsplus_jbd_debug(1, "Journal thread exiting.\n"); return 0; } static void hfsplus_jbd_start_thread(hfsplus_jbd_t *journal) { kernel_thread(hfsplus_kjournald, journal, CLONE_VM|CLONE_FS|CLONE_FILES); wait_event(journal->j_wait_done_commit, journal->j_task != 0); } static void hfsplus_jbd_kill_thread(hfsplus_jbd_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); } /* * hfsplus_jbd_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 hfsplus_jbd_write_metadata_buffer(hfsplus_transaction_t *transaction, struct hfsplus_jbd_head *jh_in, struct hfsplus_jbd_head **jh_out, 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 hfsplus_jbd_head *new_jh; struct page *new_page; unsigned int new_offset; struct buffer_head *bh_in = hfsplus_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. */ HFSPLUS_J_ASSERT_BH(bh_in, buffer_hfsplus_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. */ hfsplus_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 = hfsplus_jh2bh(jh_in)->b_page; new_offset = offset_in_page(hfsplus_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)) { printk("@@@@@@@ Oops! .. Need to check it function: %s, Line: %d\n", __FUNCTION__, __LINE__); 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; hfsplus_jbd_unlock_bh_state(bh_in); tmp = hfsplus_jbd_rep_kmalloc(bh_in->b_size, GFP_NOFS); hfsplus_jbd_lock_bh_state(bh_in); if (jh_in->b_frozen_data) { kfree(tmp); goto repeat; } jh_in->b_frozen_data = tmp; mapped_data = kmap_atomic(new_page, KM_USER0); memcpy(tmp, mapped_data + new_offset, hfsplus_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); hfsplus_jbd_unlock_bh_state(bh_in); new_jh = hfsplus_jbd_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 = hfsplus_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. */ HFSPLUS_JBUFFER_TRACE(jh_in, "file as HFSPLUS_BJ_Shadow"); hfsplus_jbd_file_buffer(jh_in, transaction, HFSPLUS_BJ_Shadow); HFSPLUS_JBUFFER_TRACE(new_jh, "file as HFSPLUS_BJ_IO"); hfsplus_jbd_file_buffer(new_jh, transaction, HFSPLUS_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. */ /* * __hfsplus__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 __hfsplus__log_space_left(hfsplus_jbd_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 __hfsplus__log_start_commit(hfsplus_jbd_t *journal, hfsplus_jbd_tid_t target) { /* * Are we already doing a recent enough commit? */ if (!hfsplus_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; hfsplus_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 hfsplus_log_start_commit(hfsplus_jbd_t *journal, hfsplus_jbd_tid_t tid) { int ret; spin_lock(&journal->j_state_lock); ret = __hfsplus__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 hfsplus_jbd_force_commit_nested(hfsplus_jbd_t *journal) { hfsplus_transaction_t *transaction = NULL; hfsplus_jbd_tid_t tid; spin_lock(&journal->j_state_lock); if (journal->j_running_transaction && !current->journal_info) { transaction = journal->j_running_transaction; __hfsplus__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); hfsplus_jbd_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 hfsplus_jbd_start_commit(hfsplus_jbd_t *journal, hfsplus_jbd_tid_t *ptid) { int ret = 0; spin_lock(&journal->j_state_lock); if (journal->j_running_transaction) { hfsplus_jbd_tid_t tid = journal->j_running_transaction->t_tid; ret = __hfsplus__log_start_commit(journal, tid); if (ret && ptid) *ptid = tid; } else if (journal->j_committing_transaction && ptid) { /* * If hfsplus_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 hfsplus_jbd_log_wait_commit(hfsplus_jbd_t *journal, hfsplus_jbd_tid_t tid) { int err = 0; #ifdef CONFIG_JBD_DEBUG spin_lock(&journal->j_state_lock); if (!hfsplus_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 (hfsplus_tid_gt(tid, journal->j_commit_sequence)) { hfsplus_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, !hfsplus_tid_gt(tid, journal->j_commit_sequence)); spin_lock(&journal->j_state_lock); } spin_unlock(&journal->j_state_lock); if (unlikely(is_hfsplus_jbd_aborted(journal))) { printk(KERN_EMERG "journal commit I/O error\n"); err = -EIO; } return err; } /* * Log buffer allocation routines: */ int hfsplus_jbd_next_log_block(hfsplus_jbd_t *journal, unsigned long *retp) { unsigned long blocknr; spin_lock(&journal->j_state_lock); HFSPLUS_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 hfsplus_jbd_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 hfsplus_jbd_bmap(hfsplus_jbd_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; __hfsplus_jbd_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 hfsplus_jbd_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 hfsplus_jbd_head *hfsplus_jbd_get_descriptor_buffer(hfsplus_jbd_t *journal) { struct buffer_head *bh; unsigned long blocknr; int err; err = hfsplus_jbd_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); HFSPLUS_BUFFER_TRACE(bh, "return this buffer"); return hfsplus_jbd_add_journal_head(bh); } /* * Management for journal control blocks: functions to create and * destroy hfsplus_jbd_t structures, and to initialise and read existing * journal blocks from disk. */ /* First: create and setup a hfsplus_jbd_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 hfsplus_jbd_t * hfsplus_jbd_init_common (void) { hfsplus_jbd_t *journal; int err; journal = hfsplus_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); init_MUTEX(&journal->j_barrier); init_MUTEX(&journal->j_checkpoint_sem); 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 * HFSPLUS_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 = hfsplus_jbd_init_revoke(journal, HFSPLUS_JBD_REVOKE_DEFAULT_HASH); if (err) { kfree(journal); goto fail; } return journal; fail: return NULL; } /* hfsplus_jbd_init_dev and hfsplus_jbd_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. * */ /** * hfsplus_jbd_t * hfsplus_jbd_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: Lenght of the journal in blocks. * @blocksize: blocksize of journalling device * @returns: a newly created hfsplus_jbd_t * * * hfsplus_jbd_init_dev creates a journal which maps a fixed contiguous * range of blocks on an arbitrary block device. * */ hfsplus_jbd_t * hfsplus_jbd_init_dev(struct block_device *bdev, struct block_device *fs_dev, int start, int len, int blocksize) { hfsplus_jbd_t *journal = hfsplus_jbd_init_common(); struct buffer_head *bh; int n; if (!journal) return NULL; journal->j_dev = bdev; journal->j_fs_dev = fs_dev; journal->j_blk_offset = start; journal->j_maxlen = len; journal->j_blocksize = blocksize; bh = __getblk(journal->j_dev, start, journal->j_blocksize); HFSPLUS_J_ASSERT(bh != NULL); journal->j_sb_buffer = bh; journal->j_superblock = (hfsplus_jbd_superblock_t *)bh->b_data; /* journal descriptor can store up to n blocks -bzzz */ n = (journal->j_blocksize - HFSPLUS_SECTOR_SIZE) / sizeof(hfsplus_jbd_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; } return journal; } /** * hfsplus_jbd_t * hfsplus_jbd_init_inode () - creates a journal which maps to a inode. * @inode: An inode to create the journal in * * hfsplus_jbd_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. */ hfsplus_jbd_t * hfsplus_jbd_init_inode (struct inode *inode) { struct buffer_head *bh; hfsplus_jbd_t *journal = hfsplus_jbd_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; hfsplus_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(hfsplus_jbd_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 = hfsplus_jbd_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); HFSPLUS_J_ASSERT(bh != NULL); journal->j_sb_buffer = bh; journal->j_superblock = (hfsplus_jbd_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 hfsplus_jbd_fail_superblock (hfsplus_jbd_t *journal) { struct buffer_head *bh = journal->j_sb_buffer; brelse(bh); journal->j_sb_buffer = NULL; } /* * Given a hfsplus_jbd_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 hfsplus_jbd_reset(hfsplus_jbd_t *journal) { hfsplus_jbd_superblock_t *sb = journal->j_superblock; unsigned int 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. */ hfsplus_jbd_update_superblock(journal, 1); hfsplus_jbd_start_thread(journal); return 0; } /** * int hfsplus_jbd_create() - Initialise the new journal file * @journal: Journal to create. This structure must have been initialised * * Given a hfsplus_jbd_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 hfsplus_jbd_create(hfsplus_jbd_t *journal) { unsigned long blocknr; struct buffer_head *bh; hfsplus_jbd_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); hfsplus_jbd_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. */ hfsplus_jbd_debug(1, "JBD: Zeroing out journal blocks...\n"); for (i = 0; i < journal->j_maxlen; i++) { err = hfsplus_jbd_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); HFSPLUS_BUFFER_TRACE(bh, "marking dirty"); mark_buffer_dirty(bh); HFSPLUS_BUFFER_TRACE(bh, "marking uptodate"); set_buffer_uptodate(bh); unlock_buffer(bh); __brelse(bh); } sync_blockdev(journal->j_dev); hfsplus_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 hfsplus_jbd_reset(journal); } /** * void hfsplus_jbd_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 hfsplus_jbd_update_superblock(hfsplus_jbd_t *journal, int wait) { hfsplus_jbd_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) { hfsplus_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); hfsplus_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); hfsplus_jhdr_checksum_calculate(journal); spin_unlock(&journal->j_state_lock); HFSPLUS_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 hfsplus_jbd_get_superblock(hfsplus_jbd_t *journal) { struct buffer_head *bh; hfsplus_jbd_superblock_t *sb; int err = -EIO; bh = journal->j_sb_buffer; HFSPLUS_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, cpu_to_be32(sb->s_header.h_magic): %x, cpu_to_be32(sb->s_blocksize): %x\n", cpu_to_be32(sb->s_header.h_magic), cpu_to_be32(sb->s_blocksize)); 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: hfsplus_jbd_fail_superblock(journal); return err; } /* * Load the on-disk journal superblock and read the key fields into the * hfsplus_jbd_t. */ static int load_superblock(hfsplus_jbd_t *journal) { int err; hfsplus_jbd_superblock_t *sb; err = hfsplus_jbd_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 hfsplus_jbd_load() - Read journal from disk. * @journal: Journal to act on. * * Given a hfsplus_jbd_t structure which tells us which disk blocks contain * a journal, read the journal from disk to initialise the in-memory * structures. */ int hfsplus_jbd_load(hfsplus_jbd_t *journal) { int err; err = load_superblock(journal); if (err) return err; /* If this is a V2 superblock, then we have to check the * features flags on it. */ if (journal->j_format_version >= 2) { hfsplus_jbd_superblock_t *sb = journal->j_superblock; 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 (hfsplus_jbd_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 (hfsplus_jbd_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 hfsplus_jbd_destroy() - Release a hfsplus_jbd_t structure. * @journal: Journal to act on. * * Release a hfsplus_jbd_t structure once it is no longer in use by the * journaled object. */ void hfsplus_jbd_destroy(hfsplus_jbd_t *journal) { /* Wait for the commit thread to wake up and die. */ hfsplus_jbd_kill_thread(journal); /* Force a final log commit */ if (journal->j_running_transaction) hfsplus_jbd_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); hfsplus_jbd_log_do_checkpoint(journal); spin_lock(&journal->j_list_lock); } HFSPLUS_J_ASSERT(journal->j_running_transaction == NULL); HFSPLUS_J_ASSERT(journal->j_committing_transaction == NULL); HFSPLUS_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; #ifdef HFSPLUS_JOURNAL_MAC_COMPATIBLE hfsplus_journal_mark_journal_empty(journal); #endif if (journal->j_sb_buffer) { hfsplus_jbd_update_superblock(journal, 1); brelse(journal->j_sb_buffer); } if (journal->j_inode) iput(journal->j_inode); if (journal->j_revoke) hfsplus_jbd_destroy_revoke(journal); kfree(journal->j_wbuf); kfree(journal); } /** *int hfsplus_jbd_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 hfsplus_jbd_check_used_features (hfsplus_jbd_t *journal, unsigned long compat, unsigned long ro, unsigned long incompat) { hfsplus_jbd_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 hfsplus_jbd_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 hfsplus_jbd_check_available_features (hfsplus_jbd_t *journal, unsigned long compat, unsigned long ro, unsigned long incompat) { hfsplus_jbd_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 hfsplus_jbd_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 hfsplus_jbd_set_features (hfsplus_jbd_t *journal, unsigned long compat, unsigned long ro, unsigned long incompat) { hfsplus_jbd_superblock_t *sb; if (hfsplus_jbd_check_used_features(journal, compat, ro, incompat)) return 1; if (!hfsplus_jbd_check_available_features(journal, compat, ro, incompat)) return 0; hfsplus_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 hfsplus_jbd_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 hfsplus_jbd_update_format (hfsplus_jbd_t *journal) { hfsplus_jbd_superblock_t *sb; int err; err = hfsplus_jbd_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 hfsplus_jbd_convert_superblock_v1(journal, sb); default: break; } return -EINVAL; } static int hfsplus_jbd_convert_superblock_v1(hfsplus_jbd_t *journal, hfsplus_jbd_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; HFSPLUS_BUFFER_TRACE(bh, "marking dirty"); mark_buffer_dirty(bh); sync_dirty_buffer(bh); return 0; } /** * int hfsplus_jbd_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 hfsplus_jbd_flush(hfsplus_jbd_t *journal) { int err = 0; hfsplus_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; __hfsplus__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) { hfsplus_jbd_tid_t tid = transaction->t_tid; spin_unlock(&journal->j_state_lock); hfsplus_jbd_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 = hfsplus_jbd_log_do_checkpoint(journal); spin_lock(&journal->j_list_lock); } spin_unlock(&journal->j_list_lock); cleanup_hfsplus_jbd_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); hfsplus_jbd_update_superblock(journal, 1); spin_lock(&journal->j_state_lock); journal->j_tail = old_tail; HFSPLUS_J_ASSERT(!journal->j_running_transaction); HFSPLUS_J_ASSERT(!journal->j_committing_transaction); HFSPLUS_J_ASSERT(!journal->j_checkpoint_transactions); HFSPLUS_J_ASSERT(journal->j_head == journal->j_tail); HFSPLUS_J_ASSERT(journal->j_tail_sequence == journal->j_transaction_sequence); spin_unlock(&journal->j_state_lock); return err; } /** * int hfsplus_jbd_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 hfsplus_jbd_init_*() and hfsplus_jbd_load(). * * If 'write' is non-zero, then we wipe out the journal on disk; otherwise * we merely suppress recovery. */ int hfsplus_jbd_wipe(hfsplus_jbd_t *journal, int write) { hfsplus_jbd_superblock_t *sb; int err = 0; HFSPLUS_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 = hfsplus_jbd_skip_recovery(journal); if (write) hfsplus_jbd_update_superblock(journal, 1); no_recovery: return err; } /* * hfsplus_jbd_dev_name: format a character string to describe on what * device this journal is present. */ static const char *hfsplus_jbd_dev_name(hfsplus_jbd_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 __hfsplus_jbd_abort_hard(hfsplus_jbd_t *journal) { hfsplus_transaction_t *transaction; char b[BDEVNAME_SIZE]; if (journal->j_flags & JFS_ABORT) return; printk(KERN_ERR "Aborting journal on device %s.\n", hfsplus_jbd_dev_name(journal, b)); spin_lock(&journal->j_state_lock); journal->j_flags |= JFS_ABORT; transaction = journal->j_running_transaction; if (transaction) __hfsplus__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 __hfsplus_jbd_abort_soft (hfsplus_jbd_t *journal, int errno) { if (journal->j_flags & JFS_ABORT) return; if (!journal->j_errno) journal->j_errno = errno; __hfsplus_jbd_abort_hard(journal); if (errno) hfsplus_jbd_update_superblock(journal, 1); } /** * void hfsplus_jbd_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 hfsplus_jbd_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 * hfsplus_jbd_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 hfsplus_jbd_stop, which will receive the -EIO error. * * Finally, the hfsplus_jbd_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 hfsplus_jbd_abort(hfsplus_jbd_t *journal, int errno) { __hfsplus_jbd_abort_soft(journal, errno); } /** * int hfsplus_jbd_errno () - returns the journal's error state. * @journal: journal to examine. * * This is the errno numbet set with hfsplus_jbd_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 hfsplus_jbd_errno(hfsplus_jbd_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 hfsplus_jbd_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 hfsplus_jbd_clear_err(hfsplus_jbd_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 hfsplus_jbd_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 hfsplus_jbd_ack_err(hfsplus_jbd_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 hfsplus_jbd_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 * __hfsplus_jbd_kmalloc (const char *where, size_t size, gfp_t flags, int retry) { return kmalloc(size, flags | (retry ? __GFP_NOFAIL : 0)); } /* * Journal_head storage management */ static kmem_cache_t *hfsplus_jbd_head_cache; #ifdef CONFIG_JBD_DEBUG static atomic_t nr_hfsplus_jbd_heads = ATOMIC_INIT(0); #endif static int hfsplus_jbd_init_journal_head_cache(void) { int retval; HFSPLUS_J_ASSERT(hfsplus_jbd_head_cache == 0); hfsplus_jbd_head_cache = kmem_cache_create("hfsplus_jbd_head", sizeof(struct hfsplus_jbd_head), 0, /* offset */ 0, /* flags */ NULL, /* ctor */ NULL); /* dtor */ retval = 0; if (hfsplus_jbd_head_cache == 0) { retval = -ENOMEM; printk(KERN_EMERG "JBD: no memory for hfsplus_jbd_head cache\n"); } return retval; } static void hfsplus_jbd_destroy_journal_head_cache(void) { HFSPLUS_J_ASSERT(hfsplus_jbd_head_cache != NULL); kmem_cache_destroy(hfsplus_jbd_head_cache); hfsplus_jbd_head_cache = NULL; } /* * hfsplus_jbd_head splicing and dicing */ static struct hfsplus_jbd_head *hfsplus_jbd_alloc_journal_head(void) { struct hfsplus_jbd_head *ret; static unsigned long last_warning; #ifdef CONFIG_JBD_DEBUG atomic_inc(&nr_hfsplus_jbd_heads); #endif ret = kmem_cache_alloc(hfsplus_jbd_head_cache, GFP_NOFS); if (ret == 0) { printk(KERN_ERR "Out of memory for hfsplus_jbd_head\n"); if (time_after(jiffies, last_warning + 5*HZ)) { printk(KERN_ERR "ENOMEM in %s, retrying.\n", __FUNCTION__); last_warning = jiffies; } while (ret == 0) { yield(); ret = kmem_cache_alloc(hfsplus_jbd_head_cache, GFP_NOFS); if (ret == 0) printk(KERN_ERR "Again out of memory for hfsplus_jbd_head\n"); } } return ret; } static void hfsplus_jbd_free_journal_head(struct hfsplus_jbd_head *jh) { #ifdef CONFIG_JBD_DEBUG atomic_dec(&nr_hfsplus_jbd_heads); memset(jh, 0x5b, sizeof(*jh)); #endif kmem_cache_free(hfsplus_jbd_head_cache, jh); } /* * A hfsplus_jbd_head is attached to a buffer_head whenever JBD has an * interest in the buffer. * * Whenever a buffer has an attached hfsplus_jbd_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 hfsplus_jbd_head may be detached from its buffer_head when the hfsplus_jbd_head's * b_transaction, b_cp_transaction and b_next_transaction pointers are NULL. * Various places in JBD call hfsplus_jbd_remove_journal_head() to indicate that the * hfsplus_jbd_head can be dropped if needed. * * Various places in the kernel want to attach a hfsplus_jbd_head to a buffer_head * _before_ attaching the hfsplus_jbd_head to a transaction. To protect the * hfsplus_jbd_head in this situation, hfsplus_jbd_add_journal_head elevates the * hfsplus_jbd_head's b_jcount refcount by one. The caller must call * hfsplus_jbd_put_journal_head() to undo this. * * So the typical usage would be: * * (Attach a hfsplus_jbd_head if needed. Increments b_jcount) * struct hfsplus_jbd_head *jh = hfsplus_jbd_add_journal_head(bh); * ... * jh->b_transaction = xxx; * hfsplus_jbd_put_journal_head(jh); * * Now, the hfsplus_jbd_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 hfsplus_jbd_head. * * Doesn't need the journal lock. * May sleep. */ struct hfsplus_jbd_head *hfsplus_jbd_add_journal_head(struct buffer_head *bh) { struct hfsplus_jbd_head *jh; struct hfsplus_jbd_head *new_jh = NULL; repeat: if (!buffer_hfsplus_jbd(bh)) { new_jh = hfsplus_jbd_alloc_journal_head(); if (!new_jh) { printk(KERN_ERR "Error in allocating journal head\n"); return NULL; } memset(new_jh, 0, sizeof(*new_jh)); } hfsplus_jbd_lock_bh_hfsplus_jbd_head(bh); if (buffer_hfsplus_jbd(bh)) { jh = hfsplus_bh2jh(bh); } else { HFSPLUS_J_ASSERT_BH(bh, (atomic_read(&bh->b_count) > 0) || (bh->b_page && bh->b_page->mapping)); if (!new_jh) { hfsplus_jbd_unlock_bh_hfsplus_jbd_head(bh); goto repeat; } jh = new_jh; new_jh = NULL; /* We consumed it */ set_buffer_hfsplus_jbd(bh); bh->b_private = jh; jh->b_bh = bh; get_bh(bh); HFSPLUS_BUFFER_TRACE(bh, "added hfsplus_jbd_head"); } jh->b_jcount++; hfsplus_jbd_unlock_bh_hfsplus_jbd_head(bh); if (new_jh) hfsplus_jbd_free_journal_head(new_jh); return bh->b_private; } /* * Grab a ref against this buffer_head's hfsplus_jbd_head. If it ended up not * having a hfsplus_jbd_head, return NULL */ struct hfsplus_jbd_head *hfsplus_jbd_grab_journal_head(struct buffer_head *bh) { struct hfsplus_jbd_head *jh = NULL; hfsplus_jbd_lock_bh_hfsplus_jbd_head(bh); if (buffer_hfsplus_jbd(bh)) { jh = hfsplus_bh2jh(bh); jh->b_jcount++; } hfsplus_jbd_unlock_bh_hfsplus_jbd_head(bh); return jh; } static void __hfsplus_jbd_remove_journal_head(struct buffer_head *bh) { struct hfsplus_jbd_head *jh = hfsplus_bh2jh(bh); HFSPLUS_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) { HFSPLUS_J_ASSERT_JH(jh, jh->b_jlist == HFSPLUS_BJ_None); HFSPLUS_J_ASSERT_BH(bh, buffer_hfsplus_jbd(bh)); HFSPLUS_J_ASSERT_BH(bh, hfsplus_jh2bh(jh) == bh); HFSPLUS_BUFFER_TRACE(bh, "remove hfsplus_jbd_head"); if (jh->b_frozen_data) { printk(KERN_WARNING "%s: freeing " "b_frozen_data\n", __FUNCTION__); kfree(jh->b_frozen_data); } if (jh->b_committed_data) { printk(KERN_WARNING "%s: freeing " "b_committed_data\n", __FUNCTION__); kfree(jh->b_committed_data); } bh->b_private = NULL; jh->b_bh = NULL; /* debug, really */ clear_buffer_hfsplus_jbd(bh); __brelse(bh); hfsplus_jbd_free_journal_head(jh); } else { HFSPLUS_BUFFER_TRACE(bh, "journal_head was locked"); } } } /* * hfsplus_jbd_remove_journal_head(): if the buffer isn't attached to a transaction * and has a zero b_jcount then remove and release its hfsplus_jbd_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 hfsplus_jbd_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 hfsplus_jbd_remove_journal_head(struct buffer_head *bh) { hfsplus_jbd_lock_bh_hfsplus_jbd_head(bh); __hfsplus_jbd_remove_journal_head(bh); hfsplus_jbd_unlock_bh_hfsplus_jbd_head(bh); } /* * Drop a reference on the passed hfsplus_jbd_head. If it fell to zero then try to * release the hfsplus_jbd_head from the buffer_head. */ void hfsplus_jbd_put_journal_head(struct hfsplus_jbd_head *jh) { struct buffer_head *bh = hfsplus_jh2bh(jh); hfsplus_jbd_lock_bh_hfsplus_jbd_head(bh); HFSPLUS_J_ASSERT_JH(jh, jh->b_jcount > 0); --jh->b_jcount; if (!jh->b_jcount && !jh->b_transaction) { __hfsplus_jbd_remove_journal_head(bh); __brelse(bh); } hfsplus_jbd_unlock_bh_hfsplus_jbd_head(bh); } /* * /proc tunables */ #if defined(CONFIG_JBD_DEBUG) int hfsplus_jbd_enable_debug; EXPORT_SYMBOL(hfsplus_jbd_enable_debug); #endif #if defined(CONFIG_JBD_DEBUG) && defined(CONFIG_PROC_FS) static struct proc_dir_entry *proc_hfsplus_jbd_debug; static int read_hfsplus_jbd_debug(char *page, char **start, off_t off, int count, int *eof, void *data) { int ret; ret = sprintf(page + off, "%d\n", hfsplus_jbd_enable_debug); *eof = 1; return ret; } static int write_hfsplus_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'; hfsplus_jbd_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_hfsplus_jbd_debug = create_proc_entry(JBD_PROC_NAME, 0644, NULL); if (proc_hfsplus_jbd_debug) { /* Why is this so hard? */ proc_hfsplus_jbd_debug->read_proc = read_hfsplus_jbd_debug; proc_hfsplus_jbd_debug->write_proc = write_hfsplus_jbd_debug; } } static void __exit remove_jbd_proc_entry(void) { if (proc_hfsplus_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 kmem_cache_t *hfsplus_jbd_handle_cache; static int __init hfsplus_jbd_init_handle_cache(void) { hfsplus_jbd_handle_cache = kmem_cache_create("hfsplus_jbd_handle", sizeof(hfsplus_jbd_handle_t), 0, /* offset */ 0, /* flags */ NULL, /* ctor */ NULL); /* dtor */ if (hfsplus_jbd_handle_cache == NULL) { printk(KERN_EMERG "JBD: failed to create handle cache\n"); return -ENOMEM; } return 0; } static void hfsplus_jbd_destroy_handle_cache(void) { if (hfsplus_jbd_handle_cache) kmem_cache_destroy(hfsplus_jbd_handle_cache); } /* * Module startup and shutdown */ static int __init hfsplus_jbd_init_caches(void) { int ret; ret = hfsplus_jbd_init_revoke_caches(); if (ret == 0) ret = hfsplus_jbd_init_journal_head_cache(); if (ret == 0) ret = hfsplus_jbd_init_handle_cache(); return ret; } static void hfsplus_jbd_destroy_caches(void) { hfsplus_jbd_destroy_revoke_caches(); hfsplus_jbd_destroy_journal_head_cache(); hfsplus_jbd_destroy_handle_cache(); } int hfsplus_jbd_init(void) { int ret; /* Static check for data structure consistency. There's no code * invoked --- we'll just get a linker failure if things aren't right. */ extern void hfsplus_jbd_bad_superblock_size(void); if (sizeof(struct hfsplus_jbd_superblock_s) != 1024) hfsplus_jbd_bad_superblock_size(); ret = hfsplus_jbd_init_caches(); if (ret != 0) hfsplus_jbd_destroy_caches(); create_jbd_proc_entry(); return ret; } void hfsplus_jbd_exit(void) { #ifdef CONFIG_JBD_DEBUG int n = atomic_read(&nr_hfsplus_jbd_heads); if (n) printk(KERN_EMERG "JBD: leaked %d hfsplus_jbd_heads!\n", n); #endif remove_jbd_proc_entry(); hfsplus_jbd_destroy_caches(); } MODULE_LICENSE("GPL"); EXPORT_SYMBOL(hfsplus_jbd_exit); EXPORT_SYMBOL(hfsplus_jbd_init);