| /* |
| * linux/fs/jbd2/transaction.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 transaction handling code; part of the ext2fs |
| * journaling system. |
| * |
| * This file manages transactions (compound commits managed by the |
| * journaling code) and handles (individual atomic operations by the |
| * filesystem). |
| */ |
| |
| #include <linux/time.h> |
| #include <linux/fs.h> |
| #include <linux/jbd2.h> |
| #include <linux/errno.h> |
| #include <linux/slab.h> |
| #include <linux/timer.h> |
| #include <linux/mm.h> |
| #include <linux/highmem.h> |
| #include <linux/hrtimer.h> |
| |
| static void __jbd2_journal_temp_unlink_buffer(struct journal_head *jh); |
| |
| /* |
| * jbd2_get_transaction: obtain a new transaction_t object. |
| * |
| * Simply allocate and initialise a new transaction. Create it in |
| * RUNNING state and add it to the current journal (which should not |
| * have an existing running transaction: we only make a new transaction |
| * once we have started to commit the old one). |
| * |
| * Preconditions: |
| * The journal MUST be locked. We don't perform atomic mallocs on the |
| * new transaction and we can't block without protecting against other |
| * processes trying to touch the journal while it is in transition. |
| * |
| */ |
| |
| static transaction_t * |
| jbd2_get_transaction(journal_t *journal, transaction_t *transaction) |
| { |
| transaction->t_journal = journal; |
| transaction->t_state = T_RUNNING; |
| transaction->t_start_time = ktime_get(); |
| transaction->t_tid = journal->j_transaction_sequence++; |
| transaction->t_expires = jiffies + journal->j_commit_interval; |
| spin_lock_init(&transaction->t_handle_lock); |
| INIT_LIST_HEAD(&transaction->t_inode_list); |
| INIT_LIST_HEAD(&transaction->t_private_list); |
| |
| /* Set up the commit timer for the new transaction. */ |
| journal->j_commit_timer.expires = round_jiffies(transaction->t_expires); |
| add_timer(&journal->j_commit_timer); |
| |
| J_ASSERT(journal->j_running_transaction == NULL); |
| journal->j_running_transaction = transaction; |
| transaction->t_max_wait = 0; |
| transaction->t_start = jiffies; |
| |
| return transaction; |
| } |
| |
| /* |
| * Handle management. |
| * |
| * A handle_t is an object which represents a single atomic update to a |
| * filesystem, and which tracks all of the modifications which form part |
| * of that one update. |
| */ |
| |
| /* |
| * start_this_handle: Given a handle, deal with any locking or stalling |
| * needed to make sure that there is enough journal space for the handle |
| * to begin. Attach the handle to a transaction and set up the |
| * transaction's buffer credits. |
| */ |
| |
| static int start_this_handle(journal_t *journal, handle_t *handle) |
| { |
| transaction_t *transaction; |
| int needed; |
| int nblocks = handle->h_buffer_credits; |
| transaction_t *new_transaction = NULL; |
| int ret = 0; |
| unsigned long ts = jiffies; |
| |
| if (nblocks > journal->j_max_transaction_buffers) { |
| printk(KERN_ERR "JBD: %s wants too many credits (%d > %d)\n", |
| current->comm, nblocks, |
| journal->j_max_transaction_buffers); |
| ret = -ENOSPC; |
| goto out; |
| } |
| |
| alloc_transaction: |
| if (!journal->j_running_transaction) { |
| new_transaction = kzalloc(sizeof(*new_transaction), |
| GFP_NOFS|__GFP_NOFAIL); |
| if (!new_transaction) { |
| ret = -ENOMEM; |
| goto out; |
| } |
| } |
| |
| jbd_debug(3, "New handle %p going live.\n", handle); |
| |
| repeat: |
| |
| /* |
| * We need to hold j_state_lock until t_updates has been incremented, |
| * for proper journal barrier handling |
| */ |
| spin_lock(&journal->j_state_lock); |
| repeat_locked: |
| if (is_journal_aborted(journal) || |
| (journal->j_errno != 0 && !(journal->j_flags & JBD2_ACK_ERR))) { |
| spin_unlock(&journal->j_state_lock); |
| ret = -EROFS; |
| goto out; |
| } |
| |
| /* Wait on the journal's transaction barrier if necessary */ |
| if (journal->j_barrier_count) { |
| spin_unlock(&journal->j_state_lock); |
| wait_event(journal->j_wait_transaction_locked, |
| journal->j_barrier_count == 0); |
| goto repeat; |
| } |
| |
| if (!journal->j_running_transaction) { |
| if (!new_transaction) { |
| spin_unlock(&journal->j_state_lock); |
| goto alloc_transaction; |
| } |
| jbd2_get_transaction(journal, new_transaction); |
| new_transaction = NULL; |
| } |
| |
| transaction = journal->j_running_transaction; |
| |
| /* |
| * If the current transaction is locked down for commit, wait for the |
| * lock to be released. |
| */ |
| if (transaction->t_state == T_LOCKED) { |
| DEFINE_WAIT(wait); |
| |
| prepare_to_wait(&journal->j_wait_transaction_locked, |
| &wait, TASK_UNINTERRUPTIBLE); |
| spin_unlock(&journal->j_state_lock); |
| schedule(); |
| finish_wait(&journal->j_wait_transaction_locked, &wait); |
| goto repeat; |
| } |
| |
| /* |
| * If there is not enough space left in the log to write all potential |
| * buffers requested by this operation, we need to stall pending a log |
| * checkpoint to free some more log space. |
| */ |
| spin_lock(&transaction->t_handle_lock); |
| needed = transaction->t_outstanding_credits + nblocks; |
| |
| if (needed > journal->j_max_transaction_buffers) { |
| /* |
| * If the current transaction is already too large, then start |
| * to commit it: we can then go back and attach this handle to |
| * a new transaction. |
| */ |
| DEFINE_WAIT(wait); |
| |
| jbd_debug(2, "Handle %p starting new commit...\n", handle); |
| spin_unlock(&transaction->t_handle_lock); |
| prepare_to_wait(&journal->j_wait_transaction_locked, &wait, |
| TASK_UNINTERRUPTIBLE); |
| __jbd2_log_start_commit(journal, transaction->t_tid); |
| spin_unlock(&journal->j_state_lock); |
| schedule(); |
| finish_wait(&journal->j_wait_transaction_locked, &wait); |
| goto repeat; |
| } |
| |
| /* |
| * The commit code assumes that it can get enough log space |
| * without forcing a checkpoint. This is *critical* for |
| * correctness: a checkpoint of a buffer which is also |
| * associated with a committing transaction creates a deadlock, |
| * so commit simply cannot force through checkpoints. |
| * |
| * We must therefore ensure the necessary space in the journal |
| * *before* starting to dirty potentially checkpointed buffers |
| * in the new transaction. |
| * |
| * The worst part is, any transaction currently committing can |
| * reduce the free space arbitrarily. Be careful to account for |
| * those buffers when checkpointing. |
| */ |
| |
| /* |
| * @@@ AKPM: This seems rather over-defensive. We're giving commit |
| * a _lot_ of headroom: 1/4 of the journal plus the size of |
| * the committing transaction. Really, we only need to give it |
| * committing_transaction->t_outstanding_credits plus "enough" for |
| * the log control blocks. |
| * Also, this test is inconsitent with the matching one in |
| * jbd2_journal_extend(). |
| */ |
| if (__jbd2_log_space_left(journal) < jbd_space_needed(journal)) { |
| jbd_debug(2, "Handle %p waiting for checkpoint...\n", handle); |
| spin_unlock(&transaction->t_handle_lock); |
| __jbd2_log_wait_for_space(journal); |
| goto repeat_locked; |
| } |
| |
| /* OK, account for the buffers that this operation expects to |
| * use and add the handle to the running transaction. */ |
| |
| if (time_after(transaction->t_start, ts)) { |
| ts = jbd2_time_diff(ts, transaction->t_start); |
| if (ts > transaction->t_max_wait) |
| transaction->t_max_wait = ts; |
| } |
| |
| handle->h_transaction = transaction; |
| transaction->t_outstanding_credits += nblocks; |
| transaction->t_updates++; |
| transaction->t_handle_count++; |
| jbd_debug(4, "Handle %p given %d credits (total %d, free %d)\n", |
| handle, nblocks, transaction->t_outstanding_credits, |
| __jbd2_log_space_left(journal)); |
| spin_unlock(&transaction->t_handle_lock); |
| spin_unlock(&journal->j_state_lock); |
| out: |
| if (unlikely(new_transaction)) /* It's usually NULL */ |
| kfree(new_transaction); |
| return ret; |
| } |
| |
| static struct lock_class_key jbd2_handle_key; |
| |
| /* Allocate a new handle. This should probably be in a slab... */ |
| static handle_t *new_handle(int nblocks) |
| { |
| handle_t *handle = jbd2_alloc_handle(GFP_NOFS); |
| if (!handle) |
| return NULL; |
| memset(handle, 0, sizeof(*handle)); |
| handle->h_buffer_credits = nblocks; |
| handle->h_ref = 1; |
| |
| lockdep_init_map(&handle->h_lockdep_map, "jbd2_handle", |
| &jbd2_handle_key, 0); |
| |
| return handle; |
| } |
| |
| /** |
| * handle_t *jbd2_journal_start() - Obtain a new handle. |
| * @journal: Journal to start transaction on. |
| * @nblocks: number of block buffer we might modify |
| * |
| * We make sure that the transaction can guarantee at least nblocks of |
| * modified buffers in the log. We block until the log can guarantee |
| * that much space. |
| * |
| * This function is visible to journal users (like ext3fs), so is not |
| * called with the journal already locked. |
| * |
| * Return a pointer to a newly allocated handle, or NULL on failure |
| */ |
| handle_t *jbd2_journal_start(journal_t *journal, int nblocks) |
| { |
| handle_t *handle = journal_current_handle(); |
| int err; |
| |
| if (!journal) |
| return ERR_PTR(-EROFS); |
| |
| if (handle) { |
| J_ASSERT(handle->h_transaction->t_journal == journal); |
| handle->h_ref++; |
| return handle; |
| } |
| |
| handle = new_handle(nblocks); |
| if (!handle) |
| return ERR_PTR(-ENOMEM); |
| |
| current->journal_info = handle; |
| |
| err = start_this_handle(journal, handle); |
| if (err < 0) { |
| jbd2_free_handle(handle); |
| current->journal_info = NULL; |
| handle = ERR_PTR(err); |
| goto out; |
| } |
| |
| lock_map_acquire(&handle->h_lockdep_map); |
| out: |
| return handle; |
| } |
| |
| /** |
| * int jbd2_journal_extend() - extend buffer credits. |
| * @handle: handle to 'extend' |
| * @nblocks: nr blocks to try to extend by. |
| * |
| * Some transactions, such as large extends and truncates, can be done |
| * atomically all at once or in several stages. The operation requests |
| * a credit for a number of buffer modications in advance, but can |
| * extend its credit if it needs more. |
| * |
| * jbd2_journal_extend tries to give the running handle more buffer credits. |
| * It does not guarantee that allocation - this is a best-effort only. |
| * The calling process MUST be able to deal cleanly with a failure to |
| * extend here. |
| * |
| * Return 0 on success, non-zero on failure. |
| * |
| * return code < 0 implies an error |
| * return code > 0 implies normal transaction-full status. |
| */ |
| int jbd2_journal_extend(handle_t *handle, int nblocks) |
| { |
| transaction_t *transaction = handle->h_transaction; |
| journal_t *journal = transaction->t_journal; |
| int result; |
| int wanted; |
| |
| result = -EIO; |
| if (is_handle_aborted(handle)) |
| goto out; |
| |
| result = 1; |
| |
| spin_lock(&journal->j_state_lock); |
| |
| /* Don't extend a locked-down transaction! */ |
| if (handle->h_transaction->t_state != T_RUNNING) { |
| jbd_debug(3, "denied handle %p %d blocks: " |
| "transaction not running\n", handle, nblocks); |
| goto error_out; |
| } |
| |
| spin_lock(&transaction->t_handle_lock); |
| wanted = transaction->t_outstanding_credits + nblocks; |
| |
| if (wanted > journal->j_max_transaction_buffers) { |
| jbd_debug(3, "denied handle %p %d blocks: " |
| "transaction too large\n", handle, nblocks); |
| goto unlock; |
| } |
| |
| if (wanted > __jbd2_log_space_left(journal)) { |
| jbd_debug(3, "denied handle %p %d blocks: " |
| "insufficient log space\n", handle, nblocks); |
| goto unlock; |
| } |
| |
| handle->h_buffer_credits += nblocks; |
| transaction->t_outstanding_credits += nblocks; |
| result = 0; |
| |
| jbd_debug(3, "extended handle %p by %d\n", handle, nblocks); |
| unlock: |
| spin_unlock(&transaction->t_handle_lock); |
| error_out: |
| spin_unlock(&journal->j_state_lock); |
| out: |
| return result; |
| } |
| |
| |
| /** |
| * int jbd2_journal_restart() - restart a handle . |
| * @handle: handle to restart |
| * @nblocks: nr credits requested |
| * |
| * Restart a handle for a multi-transaction filesystem |
| * operation. |
| * |
| * If the jbd2_journal_extend() call above fails to grant new buffer credits |
| * to a running handle, a call to jbd2_journal_restart will commit the |
| * handle's transaction so far and reattach the handle to a new |
| * transaction capabable of guaranteeing the requested number of |
| * credits. |
| */ |
| |
| int jbd2_journal_restart(handle_t *handle, int nblocks) |
| { |
| transaction_t *transaction = handle->h_transaction; |
| journal_t *journal = transaction->t_journal; |
| int ret; |
| |
| /* If we've had an abort of any type, don't even think about |
| * actually doing the restart! */ |
| if (is_handle_aborted(handle)) |
| return 0; |
| |
| /* |
| * First unlink the handle from its current transaction, and start the |
| * commit on that. |
| */ |
| J_ASSERT(transaction->t_updates > 0); |
| J_ASSERT(journal_current_handle() == handle); |
| |
| spin_lock(&journal->j_state_lock); |
| spin_lock(&transaction->t_handle_lock); |
| transaction->t_outstanding_credits -= handle->h_buffer_credits; |
| transaction->t_updates--; |
| |
| if (!transaction->t_updates) |
| wake_up(&journal->j_wait_updates); |
| spin_unlock(&transaction->t_handle_lock); |
| |
| jbd_debug(2, "restarting handle %p\n", handle); |
| __jbd2_log_start_commit(journal, transaction->t_tid); |
| spin_unlock(&journal->j_state_lock); |
| |
| handle->h_buffer_credits = nblocks; |
| ret = start_this_handle(journal, handle); |
| return ret; |
| } |
| |
| |
| /** |
| * void jbd2_journal_lock_updates () - establish a transaction barrier. |
| * @journal: Journal to establish a barrier on. |
| * |
| * This locks out any further updates from being started, and blocks |
| * until all existing updates have completed, returning only once the |
| * journal is in a quiescent state with no updates running. |
| * |
| * The journal lock should not be held on entry. |
| */ |
| void jbd2_journal_lock_updates(journal_t *journal) |
| { |
| DEFINE_WAIT(wait); |
| |
| spin_lock(&journal->j_state_lock); |
| ++journal->j_barrier_count; |
| |
| /* Wait until there are no running updates */ |
| while (1) { |
| transaction_t *transaction = journal->j_running_transaction; |
| |
| if (!transaction) |
| break; |
| |
| spin_lock(&transaction->t_handle_lock); |
| if (!transaction->t_updates) { |
| spin_unlock(&transaction->t_handle_lock); |
| break; |
| } |
| prepare_to_wait(&journal->j_wait_updates, &wait, |
| TASK_UNINTERRUPTIBLE); |
| spin_unlock(&transaction->t_handle_lock); |
| spin_unlock(&journal->j_state_lock); |
| schedule(); |
| finish_wait(&journal->j_wait_updates, &wait); |
| spin_lock(&journal->j_state_lock); |
| } |
| spin_unlock(&journal->j_state_lock); |
| |
| /* |
| * We have now established a barrier against other normal updates, but |
| * we also need to barrier against other jbd2_journal_lock_updates() calls |
| * to make sure that we serialise special journal-locked operations |
| * too. |
| */ |
| mutex_lock(&journal->j_barrier); |
| } |
| |
| /** |
| * void jbd2_journal_unlock_updates (journal_t* journal) - release barrier |
| * @journal: Journal to release the barrier on. |
| * |
| * Release a transaction barrier obtained with jbd2_journal_lock_updates(). |
| * |
| * Should be called without the journal lock held. |
| */ |
| void jbd2_journal_unlock_updates (journal_t *journal) |
| { |
| J_ASSERT(journal->j_barrier_count != 0); |
| |
| mutex_unlock(&journal->j_barrier); |
| spin_lock(&journal->j_state_lock); |
| --journal->j_barrier_count; |
| spin_unlock(&journal->j_state_lock); |
| wake_up(&journal->j_wait_transaction_locked); |
| } |
| |
| /* |
| * Report any unexpected dirty buffers which turn up. Normally those |
| * indicate an error, but they can occur if the user is running (say) |
| * tune2fs to modify the live filesystem, so we need the option of |
| * continuing as gracefully as possible. # |
| * |
| * The caller should already hold the journal lock and |
| * j_list_lock spinlock: most callers will need those anyway |
| * in order to probe the buffer's journaling state safely. |
| */ |
| static void jbd_unexpected_dirty_buffer(struct journal_head *jh) |
| { |
| int jlist; |
| |
| /* If this buffer is one which might reasonably be dirty |
| * --- ie. data, or not part of this journal --- then |
| * we're OK to leave it alone, but otherwise we need to |
| * move the dirty bit to the journal's own internal |
| * JBDDirty bit. */ |
| jlist = jh->b_jlist; |
| |
| if (jlist == BJ_Metadata || jlist == BJ_Reserved || |
| jlist == BJ_Shadow || jlist == BJ_Forget) { |
| struct buffer_head *bh = jh2bh(jh); |
| |
| if (test_clear_buffer_dirty(bh)) |
| set_buffer_jbddirty(bh); |
| } |
| } |
| |
| /* |
| * If the buffer is already part of the current transaction, then there |
| * is nothing we need to do. If it is already part of a prior |
| * transaction which we are still committing to disk, then we need to |
| * make sure that we do not overwrite the old copy: we do copy-out to |
| * preserve the copy going to disk. We also account the buffer against |
| * the handle's metadata buffer credits (unless the buffer is already |
| * part of the transaction, that is). |
| * |
| */ |
| static int |
| do_get_write_access(handle_t *handle, struct journal_head *jh, |
| int force_copy) |
| { |
| struct buffer_head *bh; |
| transaction_t *transaction; |
| journal_t *journal; |
| int error; |
| char *frozen_buffer = NULL; |
| int need_copy = 0; |
| |
| if (is_handle_aborted(handle)) |
| return -EROFS; |
| |
| transaction = handle->h_transaction; |
| journal = transaction->t_journal; |
| |
| jbd_debug(5, "buffer_head %p, force_copy %d\n", jh, force_copy); |
| |
| JBUFFER_TRACE(jh, "entry"); |
| repeat: |
| bh = jh2bh(jh); |
| |
| /* @@@ Need to check for errors here at some point. */ |
| |
| lock_buffer(bh); |
| jbd_lock_bh_state(bh); |
| |
| /* We now hold the buffer lock so it is safe to query the buffer |
| * state. Is the buffer dirty? |
| * |
| * If so, there are two possibilities. The buffer may be |
| * non-journaled, and undergoing a quite legitimate writeback. |
| * Otherwise, it is journaled, and we don't expect dirty buffers |
| * in that state (the buffers should be marked JBD_Dirty |
| * instead.) So either the IO is being done under our own |
| * control and this is a bug, or it's a third party IO such as |
| * dump(8) (which may leave the buffer scheduled for read --- |
| * ie. locked but not dirty) or tune2fs (which may actually have |
| * the buffer dirtied, ugh.) */ |
| |
| if (buffer_dirty(bh)) { |
| /* |
| * First question: is this buffer already part of the current |
| * transaction or the existing committing transaction? |
| */ |
| if (jh->b_transaction) { |
| J_ASSERT_JH(jh, |
| jh->b_transaction == transaction || |
| jh->b_transaction == |
| journal->j_committing_transaction); |
| if (jh->b_next_transaction) |
| J_ASSERT_JH(jh, jh->b_next_transaction == |
| transaction); |
| } |
| /* |
| * In any case we need to clean the dirty flag and we must |
| * do it under the buffer lock to be sure we don't race |
| * with running write-out. |
| */ |
| JBUFFER_TRACE(jh, "Unexpected dirty buffer"); |
| jbd_unexpected_dirty_buffer(jh); |
| } |
| |
| unlock_buffer(bh); |
| |
| error = -EROFS; |
| if (is_handle_aborted(handle)) { |
| jbd_unlock_bh_state(bh); |
| goto out; |
| } |
| error = 0; |
| |
| /* |
| * The buffer is already part of this transaction if b_transaction or |
| * b_next_transaction points to it |
| */ |
| if (jh->b_transaction == transaction || |
| jh->b_next_transaction == transaction) |
| goto done; |
| |
| /* |
| * this is the first time this transaction is touching this buffer, |
| * reset the modified flag |
| */ |
| jh->b_modified = 0; |
| |
| /* |
| * If there is already a copy-out version of this buffer, then we don't |
| * need to make another one |
| */ |
| if (jh->b_frozen_data) { |
| JBUFFER_TRACE(jh, "has frozen data"); |
| J_ASSERT_JH(jh, jh->b_next_transaction == NULL); |
| jh->b_next_transaction = transaction; |
| goto done; |
| } |
| |
| /* Is there data here we need to preserve? */ |
| |
| if (jh->b_transaction && jh->b_transaction != transaction) { |
| JBUFFER_TRACE(jh, "owned by older transaction"); |
| J_ASSERT_JH(jh, jh->b_next_transaction == NULL); |
| J_ASSERT_JH(jh, jh->b_transaction == |
| journal->j_committing_transaction); |
| |
| /* There is one case we have to be very careful about. |
| * If the committing transaction is currently writing |
| * this buffer out to disk and has NOT made a copy-out, |
| * then we cannot modify the buffer contents at all |
| * right now. The essence of copy-out is that it is the |
| * extra copy, not the primary copy, which gets |
| * journaled. If the primary copy is already going to |
| * disk then we cannot do copy-out here. */ |
| |
| if (jh->b_jlist == BJ_Shadow) { |
| DEFINE_WAIT_BIT(wait, &bh->b_state, BH_Unshadow); |
| wait_queue_head_t *wqh; |
| |
| wqh = bit_waitqueue(&bh->b_state, BH_Unshadow); |
| |
| JBUFFER_TRACE(jh, "on shadow: sleep"); |
| jbd_unlock_bh_state(bh); |
| /* commit wakes up all shadow buffers after IO */ |
| for ( ; ; ) { |
| prepare_to_wait(wqh, &wait.wait, |
| TASK_UNINTERRUPTIBLE); |
| if (jh->b_jlist != BJ_Shadow) |
| break; |
| schedule(); |
| } |
| finish_wait(wqh, &wait.wait); |
| goto repeat; |
| } |
| |
| /* Only do the copy if the currently-owning transaction |
| * still needs it. If it is on the Forget list, the |
| * committing transaction is past that stage. The |
| * buffer had better remain locked during the kmalloc, |
| * but that should be true --- we hold the journal lock |
| * still and the buffer is already on the BUF_JOURNAL |
| * list so won't be flushed. |
| * |
| * Subtle point, though: if this is a get_undo_access, |
| * then we will be relying on the frozen_data to contain |
| * the new value of the committed_data record after the |
| * transaction, so we HAVE to force the frozen_data copy |
| * in that case. */ |
| |
| if (jh->b_jlist != BJ_Forget || force_copy) { |
| JBUFFER_TRACE(jh, "generate frozen data"); |
| if (!frozen_buffer) { |
| JBUFFER_TRACE(jh, "allocate memory for buffer"); |
| jbd_unlock_bh_state(bh); |
| frozen_buffer = |
| jbd2_alloc(jh2bh(jh)->b_size, |
| GFP_NOFS); |
| if (!frozen_buffer) { |
| printk(KERN_EMERG |
| "%s: OOM for frozen_buffer\n", |
| __func__); |
| JBUFFER_TRACE(jh, "oom!"); |
| error = -ENOMEM; |
| jbd_lock_bh_state(bh); |
| goto done; |
| } |
| goto repeat; |
| } |
| jh->b_frozen_data = frozen_buffer; |
| frozen_buffer = NULL; |
| need_copy = 1; |
| } |
| jh->b_next_transaction = transaction; |
| } |
| |
| |
| /* |
| * Finally, if the buffer is not journaled right now, we need to make |
| * sure it doesn't get written to disk before the caller actually |
| * commits the new data |
| */ |
| if (!jh->b_transaction) { |
| JBUFFER_TRACE(jh, "no transaction"); |
| J_ASSERT_JH(jh, !jh->b_next_transaction); |
| jh->b_transaction = transaction; |
| JBUFFER_TRACE(jh, "file as BJ_Reserved"); |
| spin_lock(&journal->j_list_lock); |
| __jbd2_journal_file_buffer(jh, transaction, BJ_Reserved); |
| spin_unlock(&journal->j_list_lock); |
| } |
| |
| done: |
| if (need_copy) { |
| struct page *page; |
| int offset; |
| char *source; |
| |
| J_EXPECT_JH(jh, buffer_uptodate(jh2bh(jh)), |
| "Possible IO failure.\n"); |
| page = jh2bh(jh)->b_page; |
| offset = ((unsigned long) jh2bh(jh)->b_data) & ~PAGE_MASK; |
| source = kmap_atomic(page, KM_USER0); |
| memcpy(jh->b_frozen_data, source+offset, jh2bh(jh)->b_size); |
| kunmap_atomic(source, KM_USER0); |
| } |
| jbd_unlock_bh_state(bh); |
| |
| /* |
| * If we are about to journal a buffer, then any revoke pending on it is |
| * no longer valid |
| */ |
| jbd2_journal_cancel_revoke(handle, jh); |
| |
| out: |
| if (unlikely(frozen_buffer)) /* It's usually NULL */ |
| jbd2_free(frozen_buffer, bh->b_size); |
| |
| JBUFFER_TRACE(jh, "exit"); |
| return error; |
| } |
| |
| /** |
| * int jbd2_journal_get_write_access() - notify intent to modify a buffer for metadata (not data) update. |
| * @handle: transaction to add buffer modifications to |
| * @bh: bh to be used for metadata writes |
| * @credits: variable that will receive credits for the buffer |
| * |
| * Returns an error code or 0 on success. |
| * |
| * In full data journalling mode the buffer may be of type BJ_AsyncData, |
| * because we're write()ing a buffer which is also part of a shared mapping. |
| */ |
| |
| int jbd2_journal_get_write_access(handle_t *handle, struct buffer_head *bh) |
| { |
| struct journal_head *jh = jbd2_journal_add_journal_head(bh); |
| int rc; |
| |
| /* We do not want to get caught playing with fields which the |
| * log thread also manipulates. Make sure that the buffer |
| * completes any outstanding IO before proceeding. */ |
| rc = do_get_write_access(handle, jh, 0); |
| jbd2_journal_put_journal_head(jh); |
| return rc; |
| } |
| |
| |
| /* |
| * When the user wants to journal a newly created buffer_head |
| * (ie. getblk() returned a new buffer and we are going to populate it |
| * manually rather than reading off disk), then we need to keep the |
| * buffer_head locked until it has been completely filled with new |
| * data. In this case, we should be able to make the assertion that |
| * the bh is not already part of an existing transaction. |
| * |
| * The buffer should already be locked by the caller by this point. |
| * There is no lock ranking violation: it was a newly created, |
| * unlocked buffer beforehand. */ |
| |
| /** |
| * int jbd2_journal_get_create_access () - notify intent to use newly created bh |
| * @handle: transaction to new buffer to |
| * @bh: new buffer. |
| * |
| * Call this if you create a new bh. |
| */ |
| int jbd2_journal_get_create_access(handle_t *handle, struct buffer_head *bh) |
| { |
| transaction_t *transaction = handle->h_transaction; |
| journal_t *journal = transaction->t_journal; |
| struct journal_head *jh = jbd2_journal_add_journal_head(bh); |
| int err; |
| |
| jbd_debug(5, "journal_head %p\n", jh); |
| err = -EROFS; |
| if (is_handle_aborted(handle)) |
| goto out; |
| err = 0; |
| |
| JBUFFER_TRACE(jh, "entry"); |
| /* |
| * The buffer may already belong to this transaction due to pre-zeroing |
| * in the filesystem's new_block code. It may also be on the previous, |
| * committing transaction's lists, but it HAS to be in Forget state in |
| * that case: the transaction must have deleted the buffer for it to be |
| * reused here. |
| */ |
| jbd_lock_bh_state(bh); |
| spin_lock(&journal->j_list_lock); |
| J_ASSERT_JH(jh, (jh->b_transaction == transaction || |
| jh->b_transaction == NULL || |
| (jh->b_transaction == journal->j_committing_transaction && |
| jh->b_jlist == BJ_Forget))); |
| |
| J_ASSERT_JH(jh, jh->b_next_transaction == NULL); |
| J_ASSERT_JH(jh, buffer_locked(jh2bh(jh))); |
| |
| if (jh->b_transaction == NULL) { |
| jh->b_transaction = transaction; |
| |
| /* first access by this transaction */ |
| jh->b_modified = 0; |
| |
| JBUFFER_TRACE(jh, "file as BJ_Reserved"); |
| __jbd2_journal_file_buffer(jh, transaction, BJ_Reserved); |
| } else if (jh->b_transaction == journal->j_committing_transaction) { |
| /* first access by this transaction */ |
| jh->b_modified = 0; |
| |
| JBUFFER_TRACE(jh, "set next transaction"); |
| jh->b_next_transaction = transaction; |
| } |
| spin_unlock(&journal->j_list_lock); |
| jbd_unlock_bh_state(bh); |
| |
| /* |
| * akpm: I added this. ext3_alloc_branch can pick up new indirect |
| * blocks which contain freed but then revoked metadata. We need |
| * to cancel the revoke in case we end up freeing it yet again |
| * and the reallocating as data - this would cause a second revoke, |
| * which hits an assertion error. |
| */ |
| JBUFFER_TRACE(jh, "cancelling revoke"); |
| jbd2_journal_cancel_revoke(handle, jh); |
| jbd2_journal_put_journal_head(jh); |
| out: |
| return err; |
| } |
| |
| /** |
| * int jbd2_journal_get_undo_access() - Notify intent to modify metadata with |
| * non-rewindable consequences |
| * @handle: transaction |
| * @bh: buffer to undo |
| * @credits: store the number of taken credits here (if not NULL) |
| * |
| * Sometimes there is a need to distinguish between metadata which has |
| * been committed to disk and that which has not. The ext3fs code uses |
| * this for freeing and allocating space, we have to make sure that we |
| * do not reuse freed space until the deallocation has been committed, |
| * since if we overwrote that space we would make the delete |
| * un-rewindable in case of a crash. |
| * |
| * To deal with that, jbd2_journal_get_undo_access requests write access to a |
| * buffer for parts of non-rewindable operations such as delete |
| * operations on the bitmaps. The journaling code must keep a copy of |
| * the buffer's contents prior to the undo_access call until such time |
| * as we know that the buffer has definitely been committed to disk. |
| * |
| * We never need to know which transaction the committed data is part |
| * of, buffers touched here are guaranteed to be dirtied later and so |
| * will be committed to a new transaction in due course, at which point |
| * we can discard the old committed data pointer. |
| * |
| * Returns error number or 0 on success. |
| */ |
| int jbd2_journal_get_undo_access(handle_t *handle, struct buffer_head *bh) |
| { |
| int err; |
| struct journal_head *jh = jbd2_journal_add_journal_head(bh); |
| char *committed_data = NULL; |
| |
| JBUFFER_TRACE(jh, "entry"); |
| |
| /* |
| * Do this first --- it can drop the journal lock, so we want to |
| * make sure that obtaining the committed_data is done |
| * atomically wrt. completion of any outstanding commits. |
| */ |
| err = do_get_write_access(handle, jh, 1); |
| if (err) |
| goto out; |
| |
| repeat: |
| if (!jh->b_committed_data) { |
| committed_data = jbd2_alloc(jh2bh(jh)->b_size, GFP_NOFS); |
| if (!committed_data) { |
| printk(KERN_EMERG "%s: No memory for committed data\n", |
| __func__); |
| err = -ENOMEM; |
| goto out; |
| } |
| } |
| |
| jbd_lock_bh_state(bh); |
| if (!jh->b_committed_data) { |
| /* Copy out the current buffer contents into the |
| * preserved, committed copy. */ |
| JBUFFER_TRACE(jh, "generate b_committed data"); |
| if (!committed_data) { |
| jbd_unlock_bh_state(bh); |
| goto repeat; |
| } |
| |
| jh->b_committed_data = committed_data; |
| committed_data = NULL; |
| memcpy(jh->b_committed_data, bh->b_data, bh->b_size); |
| } |
| jbd_unlock_bh_state(bh); |
| out: |
| jbd2_journal_put_journal_head(jh); |
| if (unlikely(committed_data)) |
| jbd2_free(committed_data, bh->b_size); |
| return err; |
| } |
| |
| /** |
| * int jbd2_journal_dirty_metadata() - mark a buffer as containing dirty metadata |
| * @handle: transaction to add buffer to. |
| * @bh: buffer to mark |
| * |
| * mark dirty metadata which needs to be journaled as part of the current |
| * transaction. |
| * |
| * The buffer is placed on the transaction's metadata list and is marked |
| * as belonging to the transaction. |
| * |
| * Returns error number or 0 on success. |
| * |
| * Special care needs to be taken if the buffer already belongs to the |
| * current committing transaction (in which case we should have frozen |
| * data present for that commit). In that case, we don't relink the |
| * buffer: that only gets done when the old transaction finally |
| * completes its commit. |
| */ |
| int jbd2_journal_dirty_metadata(handle_t *handle, struct buffer_head *bh) |
| { |
| transaction_t *transaction = handle->h_transaction; |
| journal_t *journal = transaction->t_journal; |
| struct journal_head *jh = bh2jh(bh); |
| |
| jbd_debug(5, "journal_head %p\n", jh); |
| JBUFFER_TRACE(jh, "entry"); |
| if (is_handle_aborted(handle)) |
| goto out; |
| |
| jbd_lock_bh_state(bh); |
| |
| if (jh->b_modified == 0) { |
| /* |
| * This buffer's got modified and becoming part |
| * of the transaction. This needs to be done |
| * once a transaction -bzzz |
| */ |
| jh->b_modified = 1; |
| J_ASSERT_JH(jh, handle->h_buffer_credits > 0); |
| handle->h_buffer_credits--; |
| } |
| |
| /* |
| * fastpath, to avoid expensive locking. If this buffer is already |
| * on the running transaction's metadata list there is nothing to do. |
| * Nobody can take it off again because there is a handle open. |
| * I _think_ we're OK here with SMP barriers - a mistaken decision will |
| * result in this test being false, so we go in and take the locks. |
| */ |
| if (jh->b_transaction == transaction && jh->b_jlist == BJ_Metadata) { |
| JBUFFER_TRACE(jh, "fastpath"); |
| J_ASSERT_JH(jh, jh->b_transaction == |
| journal->j_running_transaction); |
| goto out_unlock_bh; |
| } |
| |
| set_buffer_jbddirty(bh); |
| |
| /* |
| * Metadata already on the current transaction list doesn't |
| * need to be filed. Metadata on another transaction's list must |
| * be committing, and will be refiled once the commit completes: |
| * leave it alone for now. |
| */ |
| if (jh->b_transaction != transaction) { |
| JBUFFER_TRACE(jh, "already on other transaction"); |
| J_ASSERT_JH(jh, jh->b_transaction == |
| journal->j_committing_transaction); |
| J_ASSERT_JH(jh, jh->b_next_transaction == transaction); |
| /* And this case is illegal: we can't reuse another |
| * transaction's data buffer, ever. */ |
| goto out_unlock_bh; |
| } |
| |
| /* That test should have eliminated the following case: */ |
| J_ASSERT_JH(jh, jh->b_frozen_data == NULL); |
| |
| JBUFFER_TRACE(jh, "file as BJ_Metadata"); |
| spin_lock(&journal->j_list_lock); |
| __jbd2_journal_file_buffer(jh, handle->h_transaction, BJ_Metadata); |
| spin_unlock(&journal->j_list_lock); |
| out_unlock_bh: |
| jbd_unlock_bh_state(bh); |
| out: |
| JBUFFER_TRACE(jh, "exit"); |
| return 0; |
| } |
| |
| /* |
| * jbd2_journal_release_buffer: undo a get_write_access without any buffer |
| * updates, if the update decided in the end that it didn't need access. |
| * |
| */ |
| void |
| jbd2_journal_release_buffer(handle_t *handle, struct buffer_head *bh) |
| { |
| BUFFER_TRACE(bh, "entry"); |
| } |
| |
| /** |
| * void jbd2_journal_forget() - bforget() for potentially-journaled buffers. |
| * @handle: transaction handle |
| * @bh: bh to 'forget' |
| * |
| * We can only do the bforget if there are no commits pending against the |
| * buffer. If the buffer is dirty in the current running transaction we |
| * can safely unlink it. |
| * |
| * bh may not be a journalled buffer at all - it may be a non-JBD |
| * buffer which came off the hashtable. Check for this. |
| * |
| * Decrements bh->b_count by one. |
| * |
| * Allow this call even if the handle has aborted --- it may be part of |
| * the caller's cleanup after an abort. |
| */ |
| int jbd2_journal_forget (handle_t *handle, struct buffer_head *bh) |
| { |
| transaction_t *transaction = handle->h_transaction; |
| journal_t *journal = transaction->t_journal; |
| struct journal_head *jh; |
| int drop_reserve = 0; |
| int err = 0; |
| int was_modified = 0; |
| |
| BUFFER_TRACE(bh, "entry"); |
| |
| jbd_lock_bh_state(bh); |
| spin_lock(&journal->j_list_lock); |
| |
| if (!buffer_jbd(bh)) |
| goto not_jbd; |
| jh = bh2jh(bh); |
| |
| /* Critical error: attempting to delete a bitmap buffer, maybe? |
| * Don't do any jbd operations, and return an error. */ |
| if (!J_EXPECT_JH(jh, !jh->b_committed_data, |
| "inconsistent data on disk")) { |
| err = -EIO; |
| goto not_jbd; |
| } |
| |
| /* keep track of wether or not this transaction modified us */ |
| was_modified = jh->b_modified; |
| |
| /* |
| * The buffer's going from the transaction, we must drop |
| * all references -bzzz |
| */ |
| jh->b_modified = 0; |
| |
| if (jh->b_transaction == handle->h_transaction) { |
| J_ASSERT_JH(jh, !jh->b_frozen_data); |
| |
| /* If we are forgetting a buffer which is already part |
| * of this transaction, then we can just drop it from |
| * the transaction immediately. */ |
| clear_buffer_dirty(bh); |
| clear_buffer_jbddirty(bh); |
| |
| JBUFFER_TRACE(jh, "belongs to current transaction: unfile"); |
| |
| /* |
| * we only want to drop a reference if this transaction |
| * modified the buffer |
| */ |
| if (was_modified) |
| drop_reserve = 1; |
| |
| /* |
| * We are no longer going to journal this buffer. |
| * However, the commit of this transaction is still |
| * important to the buffer: the delete that we are now |
| * processing might obsolete an old log entry, so by |
| * committing, we can satisfy the buffer's checkpoint. |
| * |
| * So, if we have a checkpoint on the buffer, we should |
| * now refile the buffer on our BJ_Forget list so that |
| * we know to remove the checkpoint after we commit. |
| */ |
| |
| if (jh->b_cp_transaction) { |
| __jbd2_journal_temp_unlink_buffer(jh); |
| __jbd2_journal_file_buffer(jh, transaction, BJ_Forget); |
| } else { |
| __jbd2_journal_unfile_buffer(jh); |
| jbd2_journal_remove_journal_head(bh); |
| __brelse(bh); |
| if (!buffer_jbd(bh)) { |
| spin_unlock(&journal->j_list_lock); |
| jbd_unlock_bh_state(bh); |
| __bforget(bh); |
| goto drop; |
| } |
| } |
| } else if (jh->b_transaction) { |
| J_ASSERT_JH(jh, (jh->b_transaction == |
| journal->j_committing_transaction)); |
| /* However, if the buffer is still owned by a prior |
| * (committing) transaction, we can't drop it yet... */ |
| JBUFFER_TRACE(jh, "belongs to older transaction"); |
| /* ... but we CAN drop it from the new transaction if we |
| * have also modified it since the original commit. */ |
| |
| if (jh->b_next_transaction) { |
| J_ASSERT(jh->b_next_transaction == transaction); |
| jh->b_next_transaction = NULL; |
| |
| /* |
| * only drop a reference if this transaction modified |
| * the buffer |
| */ |
| if (was_modified) |
| drop_reserve = 1; |
| } |
| } |
| |
| not_jbd: |
| spin_unlock(&journal->j_list_lock); |
| jbd_unlock_bh_state(bh); |
| __brelse(bh); |
| drop: |
| if (drop_reserve) { |
| /* no need to reserve log space for this block -bzzz */ |
| handle->h_buffer_credits++; |
| } |
| return err; |
| } |
| |
| /** |
| * int jbd2_journal_stop() - complete a transaction |
| * @handle: tranaction to complete. |
| * |
| * All done for a particular handle. |
| * |
| * There is not much action needed here. We just return any remaining |
| * buffer credits to the transaction and remove the handle. The only |
| * complication is that we need to start a commit operation if the |
| * filesystem is marked for synchronous update. |
| * |
| * jbd2_journal_stop itself will not usually return an error, but it may |
| * do so in unusual circumstances. In particular, expect it to |
| * return -EIO if a jbd2_journal_abort has been executed since the |
| * transaction began. |
| */ |
| int jbd2_journal_stop(handle_t *handle) |
| { |
| transaction_t *transaction = handle->h_transaction; |
| journal_t *journal = transaction->t_journal; |
| int err; |
| pid_t pid; |
| |
| J_ASSERT(journal_current_handle() == handle); |
| |
| if (is_handle_aborted(handle)) |
| err = -EIO; |
| else { |
| J_ASSERT(transaction->t_updates > 0); |
| err = 0; |
| } |
| |
| if (--handle->h_ref > 0) { |
| jbd_debug(4, "h_ref %d -> %d\n", handle->h_ref + 1, |
| handle->h_ref); |
| return err; |
| } |
| |
| jbd_debug(4, "Handle %p going down\n", handle); |
| |
| /* |
| * Implement synchronous transaction batching. If the handle |
| * was synchronous, don't force a commit immediately. Let's |
| * yield and let another thread piggyback onto this |
| * transaction. Keep doing that while new threads continue to |
| * arrive. It doesn't cost much - we're about to run a commit |
| * and sleep on IO anyway. Speeds up many-threaded, many-dir |
| * operations by 30x or more... |
| * |
| * We try and optimize the sleep time against what the |
| * underlying disk can do, instead of having a static sleep |
| * time. This is useful for the case where our storage is so |
| * fast that it is more optimal to go ahead and force a flush |
| * and wait for the transaction to be committed than it is to |
| * wait for an arbitrary amount of time for new writers to |
| * join the transaction. We achieve this by measuring how |
| * long it takes to commit a transaction, and compare it with |
| * how long this transaction has been running, and if run time |
| * < commit time then we sleep for the delta and commit. This |
| * greatly helps super fast disks that would see slowdowns as |
| * more threads started doing fsyncs. |
| * |
| * But don't do this if this process was the most recent one |
| * to perform a synchronous write. We do this to detect the |
| * case where a single process is doing a stream of sync |
| * writes. No point in waiting for joiners in that case. |
| */ |
| pid = current->pid; |
| if (handle->h_sync && journal->j_last_sync_writer != pid) { |
| u64 commit_time, trans_time; |
| |
| journal->j_last_sync_writer = pid; |
| |
| spin_lock(&journal->j_state_lock); |
| commit_time = journal->j_average_commit_time; |
| spin_unlock(&journal->j_state_lock); |
| |
| trans_time = ktime_to_ns(ktime_sub(ktime_get(), |
| transaction->t_start_time)); |
| |
| commit_time = max_t(u64, commit_time, |
| 1000*journal->j_min_batch_time); |
| commit_time = min_t(u64, commit_time, |
| 1000*journal->j_max_batch_time); |
| |
| if (trans_time < commit_time) { |
| ktime_t expires = ktime_add_ns(ktime_get(), |
| commit_time); |
| set_current_state(TASK_UNINTERRUPTIBLE); |
| schedule_hrtimeout(&expires, HRTIMER_MODE_ABS); |
| } |
| } |
| |
| current->journal_info = NULL; |
| spin_lock(&journal->j_state_lock); |
| spin_lock(&transaction->t_handle_lock); |
| transaction->t_outstanding_credits -= handle->h_buffer_credits; |
| transaction->t_updates--; |
| if (!transaction->t_updates) { |
| wake_up(&journal->j_wait_updates); |
| if (journal->j_barrier_count) |
| wake_up(&journal->j_wait_transaction_locked); |
| } |
| |
| /* |
| * If the handle is marked SYNC, we need to set another commit |
| * going! We also want to force a commit if the current |
| * transaction is occupying too much of the log, or if the |
| * transaction is too old now. |
| */ |
| if (handle->h_sync || |
| transaction->t_outstanding_credits > |
| journal->j_max_transaction_buffers || |
| time_after_eq(jiffies, transaction->t_expires)) { |
| /* Do this even for aborted journals: an abort still |
| * completes the commit thread, it just doesn't write |
| * anything to disk. */ |
| tid_t tid = transaction->t_tid; |
| |
| spin_unlock(&transaction->t_handle_lock); |
| jbd_debug(2, "transaction too old, requesting commit for " |
| "handle %p\n", handle); |
| /* This is non-blocking */ |
| __jbd2_log_start_commit(journal, transaction->t_tid); |
| spin_unlock(&journal->j_state_lock); |
| |
| /* |
| * Special case: JBD2_SYNC synchronous updates require us |
| * to wait for the commit to complete. |
| */ |
| if (handle->h_sync && !(current->flags & PF_MEMALLOC)) |
| err = jbd2_log_wait_commit(journal, tid); |
| } else { |
| spin_unlock(&transaction->t_handle_lock); |
| spin_unlock(&journal->j_state_lock); |
| } |
| |
| lock_map_release(&handle->h_lockdep_map); |
| |
| jbd2_free_handle(handle); |
| return err; |
| } |
| |
| /** |
| * int jbd2_journal_force_commit() - force any uncommitted transactions |
| * @journal: journal to force |
| * |
| * For synchronous operations: force any uncommitted transactions |
| * to disk. May seem kludgy, but it reuses all the handle batching |
| * code in a very simple manner. |
| */ |
| int jbd2_journal_force_commit(journal_t *journal) |
| { |
| handle_t *handle; |
| int ret; |
| |
| handle = jbd2_journal_start(journal, 1); |
| if (IS_ERR(handle)) { |
| ret = PTR_ERR(handle); |
| } else { |
| handle->h_sync = 1; |
| ret = jbd2_journal_stop(handle); |
| } |
| return ret; |
| } |
| |
| /* |
| * |
| * List management code snippets: various functions for manipulating the |
| * transaction buffer lists. |
| * |
| */ |
| |
| /* |
| * Append a buffer to a transaction list, given the transaction's list head |
| * pointer. |
| * |
| * j_list_lock is held. |
| * |
| * jbd_lock_bh_state(jh2bh(jh)) is held. |
| */ |
| |
| static inline void |
| __blist_add_buffer(struct journal_head **list, struct journal_head *jh) |
| { |
| if (!*list) { |
| jh->b_tnext = jh->b_tprev = jh; |
| *list = jh; |
| } else { |
| /* Insert at the tail of the list to preserve order */ |
| struct journal_head *first = *list, *last = first->b_tprev; |
| jh->b_tprev = last; |
| jh->b_tnext = first; |
| last->b_tnext = first->b_tprev = jh; |
| } |
| } |
| |
| /* |
| * Remove a buffer from a transaction list, given the transaction's list |
| * head pointer. |
| * |
| * Called with j_list_lock held, and the journal may not be locked. |
| * |
| * jbd_lock_bh_state(jh2bh(jh)) is held. |
| */ |
| |
| static inline void |
| __blist_del_buffer(struct journal_head **list, struct journal_head *jh) |
| { |
| if (*list == jh) { |
| *list = jh->b_tnext; |
| if (*list == jh) |
| *list = NULL; |
| } |
| jh->b_tprev->b_tnext = jh->b_tnext; |
| jh->b_tnext->b_tprev = jh->b_tprev; |
| } |
| |
| /* |
| * Remove a buffer from the appropriate transaction list. |
| * |
| * Note that this function can *change* the value of |
| * bh->b_transaction->t_buffers, t_forget, t_iobuf_list, t_shadow_list, |
| * t_log_list or t_reserved_list. If the caller is holding onto a copy of one |
| * of these pointers, it could go bad. Generally the caller needs to re-read |
| * the pointer from the transaction_t. |
| * |
| * Called under j_list_lock. The journal may not be locked. |
| */ |
| void __jbd2_journal_temp_unlink_buffer(struct journal_head *jh) |
| { |
| struct journal_head **list = NULL; |
| transaction_t *transaction; |
| struct buffer_head *bh = jh2bh(jh); |
| |
| J_ASSERT_JH(jh, jbd_is_locked_bh_state(bh)); |
| transaction = jh->b_transaction; |
| if (transaction) |
| assert_spin_locked(&transaction->t_journal->j_list_lock); |
| |
| J_ASSERT_JH(jh, jh->b_jlist < BJ_Types); |
| if (jh->b_jlist != BJ_None) |
| J_ASSERT_JH(jh, transaction != NULL); |
| |
| switch (jh->b_jlist) { |
| case BJ_None: |
| return; |
| case BJ_Metadata: |
| transaction->t_nr_buffers--; |
| J_ASSERT_JH(jh, transaction->t_nr_buffers >= 0); |
| list = &transaction->t_buffers; |
| break; |
| case BJ_Forget: |
| list = &transaction->t_forget; |
| break; |
| case BJ_IO: |
| list = &transaction->t_iobuf_list; |
| break; |
| case BJ_Shadow: |
| list = &transaction->t_shadow_list; |
| break; |
| case BJ_LogCtl: |
| list = &transaction->t_log_list; |
| break; |
| case BJ_Reserved: |
| list = &transaction->t_reserved_list; |
| break; |
| } |
| |
| __blist_del_buffer(list, jh); |
| jh->b_jlist = BJ_None; |
| if (test_clear_buffer_jbddirty(bh)) |
| mark_buffer_dirty(bh); /* Expose it to the VM */ |
| } |
| |
| void __jbd2_journal_unfile_buffer(struct journal_head *jh) |
| { |
| __jbd2_journal_temp_unlink_buffer(jh); |
| jh->b_transaction = NULL; |
| } |
| |
| void jbd2_journal_unfile_buffer(journal_t *journal, struct journal_head *jh) |
| { |
| jbd_lock_bh_state(jh2bh(jh)); |
| spin_lock(&journal->j_list_lock); |
| __jbd2_journal_unfile_buffer(jh); |
| spin_unlock(&journal->j_list_lock); |
| jbd_unlock_bh_state(jh2bh(jh)); |
| } |
| |
| /* |
| * Called from jbd2_journal_try_to_free_buffers(). |
| * |
| * Called under jbd_lock_bh_state(bh) |
| */ |
| static void |
| __journal_try_to_free_buffer(journal_t *journal, struct buffer_head *bh) |
| { |
| struct journal_head *jh; |
| |
| jh = bh2jh(bh); |
| |
| if (buffer_locked(bh) || buffer_dirty(bh)) |
| goto out; |
| |
| if (jh->b_next_transaction != NULL) |
| goto out; |
| |
| spin_lock(&journal->j_list_lock); |
| if (jh->b_cp_transaction != NULL && jh->b_transaction == NULL) { |
| /* written-back checkpointed metadata buffer */ |
| if (jh->b_jlist == BJ_None) { |
| JBUFFER_TRACE(jh, "remove from checkpoint list"); |
| __jbd2_journal_remove_checkpoint(jh); |
| jbd2_journal_remove_journal_head(bh); |
| __brelse(bh); |
| } |
| } |
| spin_unlock(&journal->j_list_lock); |
| out: |
| return; |
| } |
| |
| /* |
| * jbd2_journal_try_to_free_buffers() could race with |
| * jbd2_journal_commit_transaction(). The later might still hold the |
| * reference count to the buffers when inspecting them on |
| * t_syncdata_list or t_locked_list. |
| * |
| * jbd2_journal_try_to_free_buffers() will call this function to |
| * wait for the current transaction to finish syncing data buffers, before |
| * try to free that buffer. |
| * |
| * Called with journal->j_state_lock hold. |
| */ |
| static void jbd2_journal_wait_for_transaction_sync_data(journal_t *journal) |
| { |
| transaction_t *transaction; |
| tid_t tid; |
| |
| spin_lock(&journal->j_state_lock); |
| transaction = journal->j_committing_transaction; |
| |
| if (!transaction) { |
| spin_unlock(&journal->j_state_lock); |
| return; |
| } |
| |
| tid = transaction->t_tid; |
| spin_unlock(&journal->j_state_lock); |
| jbd2_log_wait_commit(journal, tid); |
| } |
| |
| /** |
| * int jbd2_journal_try_to_free_buffers() - try to free page buffers. |
| * @journal: journal for operation |
| * @page: to try and free |
| * @gfp_mask: we use the mask to detect how hard should we try to release |
| * buffers. If __GFP_WAIT and __GFP_FS is set, we wait for commit code to |
| * release the buffers. |
| * |
| * |
| * For all the buffers on this page, |
| * if they are fully written out ordered data, move them onto BUF_CLEAN |
| * so try_to_free_buffers() can reap them. |
| * |
| * This function returns non-zero if we wish try_to_free_buffers() |
| * to be called. We do this if the page is releasable by try_to_free_buffers(). |
| * We also do it if the page has locked or dirty buffers and the caller wants |
| * us to perform sync or async writeout. |
| * |
| * This complicates JBD locking somewhat. We aren't protected by the |
| * BKL here. We wish to remove the buffer from its committing or |
| * running transaction's ->t_datalist via __jbd2_journal_unfile_buffer. |
| * |
| * This may *change* the value of transaction_t->t_datalist, so anyone |
| * who looks at t_datalist needs to lock against this function. |
| * |
| * Even worse, someone may be doing a jbd2_journal_dirty_data on this |
| * buffer. So we need to lock against that. jbd2_journal_dirty_data() |
| * will come out of the lock with the buffer dirty, which makes it |
| * ineligible for release here. |
| * |
| * Who else is affected by this? hmm... Really the only contender |
| * is do_get_write_access() - it could be looking at the buffer while |
| * journal_try_to_free_buffer() is changing its state. But that |
| * cannot happen because we never reallocate freed data as metadata |
| * while the data is part of a transaction. Yes? |
| * |
| * Return 0 on failure, 1 on success |
| */ |
| int jbd2_journal_try_to_free_buffers(journal_t *journal, |
| struct page *page, gfp_t gfp_mask) |
| { |
| struct buffer_head *head; |
| struct buffer_head *bh; |
| int ret = 0; |
| |
| J_ASSERT(PageLocked(page)); |
| |
| head = page_buffers(page); |
| bh = head; |
| do { |
| struct journal_head *jh; |
| |
| /* |
| * We take our own ref against the journal_head here to avoid |
| * having to add tons of locking around each instance of |
| * jbd2_journal_remove_journal_head() and |
| * jbd2_journal_put_journal_head(). |
| */ |
| jh = jbd2_journal_grab_journal_head(bh); |
| if (!jh) |
| continue; |
| |
| jbd_lock_bh_state(bh); |
| __journal_try_to_free_buffer(journal, bh); |
| jbd2_journal_put_journal_head(jh); |
| jbd_unlock_bh_state(bh); |
| if (buffer_jbd(bh)) |
| goto busy; |
| } while ((bh = bh->b_this_page) != head); |
| |
| ret = try_to_free_buffers(page); |
| |
| /* |
| * There are a number of places where jbd2_journal_try_to_free_buffers() |
| * could race with jbd2_journal_commit_transaction(), the later still |
| * holds the reference to the buffers to free while processing them. |
| * try_to_free_buffers() failed to free those buffers. Some of the |
| * caller of releasepage() request page buffers to be dropped, otherwise |
| * treat the fail-to-free as errors (such as generic_file_direct_IO()) |
| * |
| * So, if the caller of try_to_release_page() wants the synchronous |
| * behaviour(i.e make sure buffers are dropped upon return), |
| * let's wait for the current transaction to finish flush of |
| * dirty data buffers, then try to free those buffers again, |
| * with the journal locked. |
| */ |
| if (ret == 0 && (gfp_mask & __GFP_WAIT) && (gfp_mask & __GFP_FS)) { |
| jbd2_journal_wait_for_transaction_sync_data(journal); |
| ret = try_to_free_buffers(page); |
| } |
| |
| busy: |
| return ret; |
| } |
| |
| /* |
| * This buffer is no longer needed. If it is on an older transaction's |
| * checkpoint list we need to record it on this transaction's forget list |
| * to pin this buffer (and hence its checkpointing transaction) down until |
| * this transaction commits. If the buffer isn't on a checkpoint list, we |
| * release it. |
| * Returns non-zero if JBD no longer has an interest in the buffer. |
| * |
| * Called under j_list_lock. |
| * |
| * Called under jbd_lock_bh_state(bh). |
| */ |
| static int __dispose_buffer(struct journal_head *jh, transaction_t *transaction) |
| { |
| int may_free = 1; |
| struct buffer_head *bh = jh2bh(jh); |
| |
| __jbd2_journal_unfile_buffer(jh); |
| |
| if (jh->b_cp_transaction) { |
| JBUFFER_TRACE(jh, "on running+cp transaction"); |
| __jbd2_journal_file_buffer(jh, transaction, BJ_Forget); |
| clear_buffer_jbddirty(bh); |
| may_free = 0; |
| } else { |
| JBUFFER_TRACE(jh, "on running transaction"); |
| jbd2_journal_remove_journal_head(bh); |
| __brelse(bh); |
| } |
| return may_free; |
| } |
| |
| /* |
| * jbd2_journal_invalidatepage |
| * |
| * This code is tricky. It has a number of cases to deal with. |
| * |
| * There are two invariants which this code relies on: |
| * |
| * i_size must be updated on disk before we start calling invalidatepage on the |
| * data. |
| * |
| * This is done in ext3 by defining an ext3_setattr method which |
| * updates i_size before truncate gets going. By maintaining this |
| * invariant, we can be sure that it is safe to throw away any buffers |
| * attached to the current transaction: once the transaction commits, |
| * we know that the data will not be needed. |
| * |
| * Note however that we can *not* throw away data belonging to the |
| * previous, committing transaction! |
| * |
| * Any disk blocks which *are* part of the previous, committing |
| * transaction (and which therefore cannot be discarded immediately) are |
| * not going to be reused in the new running transaction |
| * |
| * The bitmap committed_data images guarantee this: any block which is |
| * allocated in one transaction and removed in the next will be marked |
| * as in-use in the committed_data bitmap, so cannot be reused until |
| * the next transaction to delete the block commits. This means that |
| * leaving committing buffers dirty is quite safe: the disk blocks |
| * cannot be reallocated to a different file and so buffer aliasing is |
| * not possible. |
| * |
| * |
| * The above applies mainly to ordered data mode. In writeback mode we |
| * don't make guarantees about the order in which data hits disk --- in |
| * particular we don't guarantee that new dirty data is flushed before |
| * transaction commit --- so it is always safe just to discard data |
| * immediately in that mode. --sct |
| */ |
| |
| /* |
| * The journal_unmap_buffer helper function returns zero if the buffer |
| * concerned remains pinned as an anonymous buffer belonging to an older |
| * transaction. |
| * |
| * We're outside-transaction here. Either or both of j_running_transaction |
| * and j_committing_transaction may be NULL. |
| */ |
| static int journal_unmap_buffer(journal_t *journal, struct buffer_head *bh) |
| { |
| transaction_t *transaction; |
| struct journal_head *jh; |
| int may_free = 1; |
| int ret; |
| |
| BUFFER_TRACE(bh, "entry"); |
| |
| /* |
| * It is safe to proceed here without the j_list_lock because the |
| * buffers cannot be stolen by try_to_free_buffers as long as we are |
| * holding the page lock. --sct |
| */ |
| |
| if (!buffer_jbd(bh)) |
| goto zap_buffer_unlocked; |
| |
| /* OK, we have data buffer in journaled mode */ |
| spin_lock(&journal->j_state_lock); |
| jbd_lock_bh_state(bh); |
| spin_lock(&journal->j_list_lock); |
| |
| jh = jbd2_journal_grab_journal_head(bh); |
| if (!jh) |
| goto zap_buffer_no_jh; |
| |
| transaction = jh->b_transaction; |
| if (transaction == NULL) { |
| /* First case: not on any transaction. If it |
| * has no checkpoint link, then we can zap it: |
| * it's a writeback-mode buffer so we don't care |
| * if it hits disk safely. */ |
| if (!jh->b_cp_transaction) { |
| JBUFFER_TRACE(jh, "not on any transaction: zap"); |
| goto zap_buffer; |
| } |
| |
| if (!buffer_dirty(bh)) { |
| /* bdflush has written it. We can drop it now */ |
| goto zap_buffer; |
| } |
| |
| /* OK, it must be in the journal but still not |
| * written fully to disk: it's metadata or |
| * journaled data... */ |
| |
| if (journal->j_running_transaction) { |
| /* ... and once the current transaction has |
| * committed, the buffer won't be needed any |
| * longer. */ |
| JBUFFER_TRACE(jh, "checkpointed: add to BJ_Forget"); |
| ret = __dispose_buffer(jh, |
| journal->j_running_transaction); |
| jbd2_journal_put_journal_head(jh); |
| spin_unlock(&journal->j_list_lock); |
| jbd_unlock_bh_state(bh); |
| spin_unlock(&journal->j_state_lock); |
| return ret; |
| } else { |
| /* There is no currently-running transaction. So the |
| * orphan record which we wrote for this file must have |
| * passed into commit. We must attach this buffer to |
| * the committing transaction, if it exists. */ |
| if (journal->j_committing_transaction) { |
| JBUFFER_TRACE(jh, "give to committing trans"); |
| ret = __dispose_buffer(jh, |
| journal->j_committing_transaction); |
| jbd2_journal_put_journal_head(jh); |
| spin_unlock(&journal->j_list_lock); |
| jbd_unlock_bh_state(bh); |
| spin_unlock(&journal->j_state_lock); |
| return ret; |
| } else { |
| /* The orphan record's transaction has |
| * committed. We can cleanse this buffer */ |
| clear_buffer_jbddirty(bh); |
| goto zap_buffer; |
| } |
| } |
| } else if (transaction == journal->j_committing_transaction) { |
| JBUFFER_TRACE(jh, "on committing transaction"); |
| /* |
| * If it is committing, we simply cannot touch it. We |
| * can remove it's next_transaction pointer from the |
| * running transaction if that is set, but nothing |
| * else. */ |
| set_buffer_freed(bh); |
| if (jh->b_next_transaction) { |
| J_ASSERT(jh->b_next_transaction == |
| journal->j_running_transaction); |
| jh->b_next_transaction = NULL; |
| } |
| jbd2_journal_put_journal_head(jh); |
| spin_unlock(&journal->j_list_lock); |
| jbd_unlock_bh_state(bh); |
| spin_unlock(&journal->j_state_lock); |
| return 0; |
| } else { |
| /* Good, the buffer belongs to the running transaction. |
| * We are writing our own transaction's data, not any |
| * previous one's, so it is safe to throw it away |
| * (remember that we expect the filesystem to have set |
| * i_size already for this truncate so recovery will not |
| * expose the disk blocks we are discarding here.) */ |
| J_ASSERT_JH(jh, transaction == journal->j_running_transaction); |
| JBUFFER_TRACE(jh, "on running transaction"); |
| may_free = __dispose_buffer(jh, transaction); |
| } |
| |
| zap_buffer: |
| jbd2_journal_put_journal_head(jh); |
| zap_buffer_no_jh: |
| spin_unlock(&journal->j_list_lock); |
| jbd_unlock_bh_state(bh); |
| spin_unlock(&journal->j_state_lock); |
| zap_buffer_unlocked: |
| clear_buffer_dirty(bh); |
| J_ASSERT_BH(bh, !buffer_jbddirty(bh)); |
| clear_buffer_mapped(bh); |
| clear_buffer_req(bh); |
| clear_buffer_new(bh); |
| bh->b_bdev = NULL; |
| return may_free; |
| } |
| |
| /** |
| * void jbd2_journal_invalidatepage() |
| * @journal: journal to use for flush... |
| * @page: page to flush |
| * @offset: length of page to invalidate. |
| * |
| * Reap page buffers containing data after offset in page. |
| * |
| */ |
| void jbd2_journal_invalidatepage(journal_t *journal, |
| struct page *page, |
| unsigned long offset) |
| { |
| struct buffer_head *head, *bh, *next; |
| unsigned int curr_off = 0; |
| int may_free = 1; |
| |
| if (!PageLocked(page)) |
| BUG(); |
| if (!page_has_buffers(page)) |
| return; |
| |
| /* We will potentially be playing with lists other than just the |
| * data lists (especially for journaled data mode), so be |
| * cautious in our locking. */ |
| |
| head = bh = page_buffers(page); |
| do { |
| unsigned int next_off = curr_off + bh->b_size; |
| next = bh->b_this_page; |
| |
| if (offset <= curr_off) { |
| /* This block is wholly outside the truncation point */ |
| lock_buffer(bh); |
| may_free &= journal_unmap_buffer(journal, bh); |
| unlock_buffer(bh); |
| } |
| curr_off = next_off; |
| bh = next; |
| |
| } while (bh != head); |
| |
| if (!offset) { |
| if (may_free && try_to_free_buffers(page)) |
| J_ASSERT(!page_has_buffers(page)); |
| } |
| } |
| |
| /* |
| * File a buffer on the given transaction list. |
| */ |
| void __jbd2_journal_file_buffer(struct journal_head *jh, |
| transaction_t *transaction, int jlist) |
| { |
| struct journal_head **list = NULL; |
| int was_dirty = 0; |
| struct buffer_head *bh = jh2bh(jh); |
| |
| J_ASSERT_JH(jh, jbd_is_locked_bh_state(bh)); |
| assert_spin_locked(&transaction->t_journal->j_list_lock); |
| |
| J_ASSERT_JH(jh, jh->b_jlist < BJ_Types); |
| J_ASSERT_JH(jh, jh->b_transaction == transaction || |
| jh->b_transaction == NULL); |
| |
| if (jh->b_transaction && jh->b_jlist == jlist) |
| return; |
| |
| /* The following list of buffer states needs to be consistent |
| * with __jbd_unexpected_dirty_buffer()'s handling of dirty |
| * state. */ |
| |
| if (jlist == BJ_Metadata || jlist == BJ_Reserved || |
| jlist == BJ_Shadow || jlist == BJ_Forget) { |
| if (test_clear_buffer_dirty(bh) || |
| test_clear_buffer_jbddirty(bh)) |
| was_dirty = 1; |
| } |
| |
| if (jh->b_transaction) |
| __jbd2_journal_temp_unlink_buffer(jh); |
| jh->b_transaction = transaction; |
| |
| switch (jlist) { |
| case BJ_None: |
| J_ASSERT_JH(jh, !jh->b_committed_data); |
| J_ASSERT_JH(jh, !jh->b_frozen_data); |
| return; |
| case BJ_Metadata: |
| transaction->t_nr_buffers++; |
| list = &transaction->t_buffers; |
| break; |
| case BJ_Forget: |
| list = &transaction->t_forget; |
| break; |
| case BJ_IO: |
| list = &transaction->t_iobuf_list; |
| break; |
| case BJ_Shadow: |
| list = &transaction->t_shadow_list; |
| break; |
| case BJ_LogCtl: |
| list = &transaction->t_log_list; |
| break; |
| case BJ_Reserved: |
| list = &transaction->t_reserved_list; |
| break; |
| } |
| |
| __blist_add_buffer(list, jh); |
| jh->b_jlist = jlist; |
| |
| if (was_dirty) |
| set_buffer_jbddirty(bh); |
| } |
| |
| void jbd2_journal_file_buffer(struct journal_head *jh, |
| transaction_t *transaction, int jlist) |
| { |
| jbd_lock_bh_state(jh2bh(jh)); |
| spin_lock(&transaction->t_journal->j_list_lock); |
| __jbd2_journal_file_buffer(jh, transaction, jlist); |
| spin_unlock(&transaction->t_journal->j_list_lock); |
| jbd_unlock_bh_state(jh2bh(jh)); |
| } |
| |
| /* |
| * Remove a buffer from its current buffer list in preparation for |
| * dropping it from its current transaction entirely. If the buffer has |
| * already started to be used by a subsequent transaction, refile the |
| * buffer on that transaction's metadata list. |
| * |
| * Called under journal->j_list_lock |
| * |
| * Called under jbd_lock_bh_state(jh2bh(jh)) |
| */ |
| void __jbd2_journal_refile_buffer(struct journal_head *jh) |
| { |
| int was_dirty; |
| struct buffer_head *bh = jh2bh(jh); |
| |
| J_ASSERT_JH(jh, jbd_is_locked_bh_state(bh)); |
| if (jh->b_transaction) |
| assert_spin_locked(&jh->b_transaction->t_journal->j_list_lock); |
| |
| /* If the buffer is now unused, just drop it. */ |
| if (jh->b_next_transaction == NULL) { |
| __jbd2_journal_unfile_buffer(jh); |
| return; |
| } |
| |
| /* |
| * It has been modified by a later transaction: add it to the new |
| * transaction's metadata list. |
| */ |
| |
| was_dirty = test_clear_buffer_jbddirty(bh); |
| __jbd2_journal_temp_unlink_buffer(jh); |
| jh->b_transaction = jh->b_next_transaction; |
| jh->b_next_transaction = NULL; |
| __jbd2_journal_file_buffer(jh, jh->b_transaction, |
| jh->b_modified ? BJ_Metadata : BJ_Reserved); |
| J_ASSERT_JH(jh, jh->b_transaction->t_state == T_RUNNING); |
| |
| if (was_dirty) |
| set_buffer_jbddirty(bh); |
| } |
| |
| /* |
| * For the unlocked version of this call, also make sure that any |
| * hanging journal_head is cleaned up if necessary. |
| * |
| * __jbd2_journal_refile_buffer is usually called as part of a single locked |
| * operation on a buffer_head, in which the caller is probably going to |
| * be hooking the journal_head onto other lists. In that case it is up |
| * to the caller to remove the journal_head if necessary. For the |
| * unlocked jbd2_journal_refile_buffer call, the caller isn't going to be |
| * doing anything else to the buffer so we need to do the cleanup |
| * ourselves to avoid a jh leak. |
| * |
| * *** The journal_head may be freed by this call! *** |
| */ |
| void jbd2_journal_refile_buffer(journal_t *journal, struct journal_head *jh) |
| { |
| struct buffer_head *bh = jh2bh(jh); |
| |
| jbd_lock_bh_state(bh); |
| spin_lock(&journal->j_list_lock); |
| |
| __jbd2_journal_refile_buffer(jh); |
| jbd_unlock_bh_state(bh); |
| jbd2_journal_remove_journal_head(bh); |
| |
| spin_unlock(&journal->j_list_lock); |
| __brelse(bh); |
| } |
| |
| /* |
| * File inode in the inode list of the handle's transaction |
| */ |
| int jbd2_journal_file_inode(handle_t *handle, struct jbd2_inode *jinode) |
| { |
| transaction_t *transaction = handle->h_transaction; |
| journal_t *journal = transaction->t_journal; |
| |
| if (is_handle_aborted(handle)) |
| return -EIO; |
| |
| jbd_debug(4, "Adding inode %lu, tid:%d\n", jinode->i_vfs_inode->i_ino, |
| transaction->t_tid); |
| |
| /* |
| * First check whether inode isn't already on the transaction's |
| * lists without taking the lock. Note that this check is safe |
| * without the lock as we cannot race with somebody removing inode |
| * from the transaction. The reason is that we remove inode from the |
| * transaction only in journal_release_jbd_inode() and when we commit |
| * the transaction. We are guarded from the first case by holding |
| * a reference to the inode. We are safe against the second case |
| * because if jinode->i_transaction == transaction, commit code |
| * cannot touch the transaction because we hold reference to it, |
| * and if jinode->i_next_transaction == transaction, commit code |
| * will only file the inode where we want it. |
| */ |
| if (jinode->i_transaction == transaction || |
| jinode->i_next_transaction == transaction) |
| return 0; |
| |
| spin_lock(&journal->j_list_lock); |
| |
| if (jinode->i_transaction == transaction || |
| jinode->i_next_transaction == transaction) |
| goto done; |
| |
| /* On some different transaction's list - should be |
| * the committing one */ |
| if (jinode->i_transaction) { |
| J_ASSERT(jinode->i_next_transaction == NULL); |
| J_ASSERT(jinode->i_transaction == |
| journal->j_committing_transaction); |
| jinode->i_next_transaction = transaction; |
| goto done; |
| } |
| /* Not on any transaction list... */ |
| J_ASSERT(!jinode->i_next_transaction); |
| jinode->i_transaction = transaction; |
| list_add(&jinode->i_list, &transaction->t_inode_list); |
| done: |
| spin_unlock(&journal->j_list_lock); |
| |
| return 0; |
| } |
| |
| /* |
| * This function must be called when inode is journaled in ordered mode |
| * before truncation happens. It starts writeout of truncated part in |
| * case it is in the committing transaction so that we stand to ordered |
| * mode consistency guarantees. |
| */ |
| int jbd2_journal_begin_ordered_truncate(struct jbd2_inode *inode, |
| loff_t new_size) |
| { |
| journal_t *journal; |
| transaction_t *commit_trans; |
| int ret = 0; |
| |
| if (!inode->i_transaction && !inode->i_next_transaction) |
| goto out; |
| journal = inode->i_transaction->t_journal; |
| spin_lock(&journal->j_state_lock); |
| commit_trans = journal->j_committing_transaction; |
| spin_unlock(&journal->j_state_lock); |
| if (inode->i_transaction == commit_trans) { |
| ret = filemap_fdatawrite_range(inode->i_vfs_inode->i_mapping, |
| new_size, LLONG_MAX); |
| if (ret) |
| jbd2_journal_abort(journal, ret); |
| } |
| out: |
| return ret; |
| } |