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Pull trivial branch from Jiri Kosina: "Usual stuff -- comment/printk typo fixes, documentation updates, dead code elimination." * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial: (39 commits) HOWTO: fix double words typo x86 mtrr: fix comment typo in mtrr_bp_init propagate name change to comments in kernel source doc: Update the name of profiling based on sysfs treewide: Fix typos in various drivers treewide: Fix typos in various Kconfig wireless: mwifiex: Fix typo in wireless/mwifiex driver messages: i2o: Fix typo in messages/i2o scripts/kernel-doc: check that non-void fcts describe their return value Kernel-doc: Convention: Use a "Return" section to describe return values radeon: Fix typo and copy/paste error in comments doc: Remove unnecessary declarations from Documentation/accounting/getdelays.c various: Fix spelling of "asynchronous" in comments. Fix misspellings of "whether" in comments. eisa: Fix spelling of "asynchronous". various: Fix spelling of "registered" in comments. doc: fix quite a few typos within Documentation target: iscsi: fix comment typos in target/iscsi drivers treewide: fix typo of "suport" in various comments and Kconfig treewide: fix typo of "suppport" in various comments ...
2229 lines
66 KiB
C
2229 lines
66 KiB
C
/*
|
|
* linux/fs/jbd/transaction.c
|
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*
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* Written by Stephen C. Tweedie <sct@redhat.com>, 1998
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*
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* Copyright 1998 Red Hat corp --- All Rights Reserved
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*
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* This file is part of the Linux kernel and is made available under
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* the terms of the GNU General Public License, version 2, or at your
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* option, any later version, incorporated herein by reference.
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*
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* Generic filesystem transaction handling code; part of the ext2fs
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* journaling system.
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*
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* This file manages transactions (compound commits managed by the
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* journaling code) and handles (individual atomic operations by the
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* filesystem).
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*/
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#include <linux/time.h>
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#include <linux/fs.h>
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#include <linux/jbd.h>
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#include <linux/errno.h>
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#include <linux/slab.h>
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#include <linux/timer.h>
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#include <linux/mm.h>
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#include <linux/highmem.h>
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#include <linux/hrtimer.h>
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#include <linux/backing-dev.h>
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static void __journal_temp_unlink_buffer(struct journal_head *jh);
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/*
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* get_transaction: obtain a new transaction_t object.
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*
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* Simply allocate and initialise a new transaction. Create it in
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* RUNNING state and add it to the current journal (which should not
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* have an existing running transaction: we only make a new transaction
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* once we have started to commit the old one).
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*
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* Preconditions:
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* The journal MUST be locked. We don't perform atomic mallocs on the
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* new transaction and we can't block without protecting against other
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* processes trying to touch the journal while it is in transition.
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*
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* Called under j_state_lock
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*/
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static transaction_t *
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get_transaction(journal_t *journal, transaction_t *transaction)
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{
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transaction->t_journal = journal;
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transaction->t_state = T_RUNNING;
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transaction->t_start_time = ktime_get();
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transaction->t_tid = journal->j_transaction_sequence++;
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transaction->t_expires = jiffies + journal->j_commit_interval;
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spin_lock_init(&transaction->t_handle_lock);
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/* Set up the commit timer for the new transaction. */
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journal->j_commit_timer.expires =
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round_jiffies_up(transaction->t_expires);
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add_timer(&journal->j_commit_timer);
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J_ASSERT(journal->j_running_transaction == NULL);
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journal->j_running_transaction = transaction;
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return transaction;
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}
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/*
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* Handle management.
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*
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* A handle_t is an object which represents a single atomic update to a
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* filesystem, and which tracks all of the modifications which form part
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* of that one update.
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*/
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/*
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* start_this_handle: Given a handle, deal with any locking or stalling
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* needed to make sure that there is enough journal space for the handle
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* to begin. Attach the handle to a transaction and set up the
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* transaction's buffer credits.
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*/
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static int start_this_handle(journal_t *journal, handle_t *handle)
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{
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transaction_t *transaction;
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int needed;
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int nblocks = handle->h_buffer_credits;
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transaction_t *new_transaction = NULL;
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int ret = 0;
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if (nblocks > journal->j_max_transaction_buffers) {
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printk(KERN_ERR "JBD: %s wants too many credits (%d > %d)\n",
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current->comm, nblocks,
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journal->j_max_transaction_buffers);
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ret = -ENOSPC;
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goto out;
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}
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alloc_transaction:
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if (!journal->j_running_transaction) {
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new_transaction = kzalloc(sizeof(*new_transaction), GFP_NOFS);
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if (!new_transaction) {
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congestion_wait(BLK_RW_ASYNC, HZ/50);
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goto alloc_transaction;
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}
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}
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jbd_debug(3, "New handle %p going live.\n", handle);
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repeat:
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/*
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* We need to hold j_state_lock until t_updates has been incremented,
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* for proper journal barrier handling
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*/
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spin_lock(&journal->j_state_lock);
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repeat_locked:
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if (is_journal_aborted(journal) ||
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(journal->j_errno != 0 && !(journal->j_flags & JFS_ACK_ERR))) {
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spin_unlock(&journal->j_state_lock);
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ret = -EROFS;
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goto out;
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}
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/* Wait on the journal's transaction barrier if necessary */
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if (journal->j_barrier_count) {
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spin_unlock(&journal->j_state_lock);
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wait_event(journal->j_wait_transaction_locked,
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journal->j_barrier_count == 0);
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goto repeat;
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}
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if (!journal->j_running_transaction) {
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if (!new_transaction) {
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spin_unlock(&journal->j_state_lock);
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goto alloc_transaction;
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}
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get_transaction(journal, new_transaction);
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new_transaction = NULL;
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}
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transaction = journal->j_running_transaction;
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/*
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* If the current transaction is locked down for commit, wait for the
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* lock to be released.
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*/
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if (transaction->t_state == T_LOCKED) {
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DEFINE_WAIT(wait);
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prepare_to_wait(&journal->j_wait_transaction_locked,
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&wait, TASK_UNINTERRUPTIBLE);
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spin_unlock(&journal->j_state_lock);
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schedule();
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finish_wait(&journal->j_wait_transaction_locked, &wait);
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goto repeat;
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}
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/*
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* If there is not enough space left in the log to write all potential
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* buffers requested by this operation, we need to stall pending a log
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* checkpoint to free some more log space.
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*/
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spin_lock(&transaction->t_handle_lock);
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needed = transaction->t_outstanding_credits + nblocks;
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if (needed > journal->j_max_transaction_buffers) {
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/*
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* If the current transaction is already too large, then start
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* to commit it: we can then go back and attach this handle to
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* a new transaction.
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*/
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DEFINE_WAIT(wait);
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jbd_debug(2, "Handle %p starting new commit...\n", handle);
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spin_unlock(&transaction->t_handle_lock);
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prepare_to_wait(&journal->j_wait_transaction_locked, &wait,
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TASK_UNINTERRUPTIBLE);
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__log_start_commit(journal, transaction->t_tid);
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spin_unlock(&journal->j_state_lock);
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schedule();
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finish_wait(&journal->j_wait_transaction_locked, &wait);
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goto repeat;
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}
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/*
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* The commit code assumes that it can get enough log space
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* without forcing a checkpoint. This is *critical* for
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* correctness: a checkpoint of a buffer which is also
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* associated with a committing transaction creates a deadlock,
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* so commit simply cannot force through checkpoints.
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*
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* We must therefore ensure the necessary space in the journal
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* *before* starting to dirty potentially checkpointed buffers
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* in the new transaction.
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*
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* The worst part is, any transaction currently committing can
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* reduce the free space arbitrarily. Be careful to account for
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* those buffers when checkpointing.
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*/
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/*
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* @@@ AKPM: This seems rather over-defensive. We're giving commit
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* a _lot_ of headroom: 1/4 of the journal plus the size of
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* the committing transaction. Really, we only need to give it
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* committing_transaction->t_outstanding_credits plus "enough" for
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* the log control blocks.
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* Also, this test is inconsistent with the matching one in
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* journal_extend().
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*/
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if (__log_space_left(journal) < jbd_space_needed(journal)) {
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jbd_debug(2, "Handle %p waiting for checkpoint...\n", handle);
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spin_unlock(&transaction->t_handle_lock);
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__log_wait_for_space(journal);
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goto repeat_locked;
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}
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/* OK, account for the buffers that this operation expects to
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* use and add the handle to the running transaction. */
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handle->h_transaction = transaction;
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transaction->t_outstanding_credits += nblocks;
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transaction->t_updates++;
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transaction->t_handle_count++;
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jbd_debug(4, "Handle %p given %d credits (total %d, free %d)\n",
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handle, nblocks, transaction->t_outstanding_credits,
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__log_space_left(journal));
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spin_unlock(&transaction->t_handle_lock);
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spin_unlock(&journal->j_state_lock);
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lock_map_acquire(&handle->h_lockdep_map);
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out:
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if (unlikely(new_transaction)) /* It's usually NULL */
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kfree(new_transaction);
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return ret;
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}
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static struct lock_class_key jbd_handle_key;
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/* Allocate a new handle. This should probably be in a slab... */
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static handle_t *new_handle(int nblocks)
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{
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handle_t *handle = jbd_alloc_handle(GFP_NOFS);
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if (!handle)
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return NULL;
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memset(handle, 0, sizeof(*handle));
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handle->h_buffer_credits = nblocks;
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handle->h_ref = 1;
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lockdep_init_map(&handle->h_lockdep_map, "jbd_handle", &jbd_handle_key, 0);
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return handle;
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}
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/**
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* handle_t *journal_start() - Obtain a new handle.
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* @journal: Journal to start transaction on.
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* @nblocks: number of block buffer we might modify
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*
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* We make sure that the transaction can guarantee at least nblocks of
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* modified buffers in the log. We block until the log can guarantee
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* that much space.
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*
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* This function is visible to journal users (like ext3fs), so is not
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* called with the journal already locked.
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*
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* Return a pointer to a newly allocated handle, or an ERR_PTR() value
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* on failure.
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*/
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handle_t *journal_start(journal_t *journal, int nblocks)
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{
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handle_t *handle = journal_current_handle();
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int err;
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|
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if (!journal)
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return ERR_PTR(-EROFS);
|
|
|
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if (handle) {
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J_ASSERT(handle->h_transaction->t_journal == journal);
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handle->h_ref++;
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return handle;
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}
|
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handle = new_handle(nblocks);
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if (!handle)
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return ERR_PTR(-ENOMEM);
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|
|
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current->journal_info = handle;
|
|
|
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err = start_this_handle(journal, handle);
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if (err < 0) {
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jbd_free_handle(handle);
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current->journal_info = NULL;
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handle = ERR_PTR(err);
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}
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return handle;
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}
|
|
|
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/**
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* int journal_extend() - extend buffer credits.
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* @handle: handle to 'extend'
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* @nblocks: nr blocks to try to extend by.
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*
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* Some transactions, such as large extends and truncates, can be done
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* atomically all at once or in several stages. The operation requests
|
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* a credit for a number of buffer modications in advance, but can
|
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* extend its credit if it needs more.
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*
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* journal_extend tries to give the running handle more buffer credits.
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* It does not guarantee that allocation - this is a best-effort only.
|
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* The calling process MUST be able to deal cleanly with a failure to
|
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* extend here.
|
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*
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* Return 0 on success, non-zero on failure.
|
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*
|
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* return code < 0 implies an error
|
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* return code > 0 implies normal transaction-full status.
|
|
*/
|
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int 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 > __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 journal_restart() - restart a handle.
|
|
* @handle: handle to restart
|
|
* @nblocks: nr credits requested
|
|
*
|
|
* Restart a handle for a multi-transaction filesystem
|
|
* operation.
|
|
*
|
|
* If the journal_extend() call above fails to grant new buffer credits
|
|
* to a running handle, a call to 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 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);
|
|
__log_start_commit(journal, transaction->t_tid);
|
|
spin_unlock(&journal->j_state_lock);
|
|
|
|
lock_map_release(&handle->h_lockdep_map);
|
|
handle->h_buffer_credits = nblocks;
|
|
ret = start_this_handle(journal, handle);
|
|
return ret;
|
|
}
|
|
|
|
|
|
/**
|
|
* void 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.
|
|
*
|
|
* We do not use simple mutex for synchronization as there are syscalls which
|
|
* want to return with filesystem locked and that trips up lockdep. Also
|
|
* hibernate needs to lock filesystem but locked mutex then blocks hibernation.
|
|
* Since locking filesystem is rare operation, we use simple counter and
|
|
* waitqueue for locking.
|
|
*/
|
|
void journal_lock_updates(journal_t *journal)
|
|
{
|
|
DEFINE_WAIT(wait);
|
|
|
|
wait:
|
|
/* Wait for previous locked operation to finish */
|
|
wait_event(journal->j_wait_transaction_locked,
|
|
journal->j_barrier_count == 0);
|
|
|
|
spin_lock(&journal->j_state_lock);
|
|
/*
|
|
* Check reliably under the lock whether we are the ones winning the race
|
|
* and locking the journal
|
|
*/
|
|
if (journal->j_barrier_count > 0) {
|
|
spin_unlock(&journal->j_state_lock);
|
|
goto wait;
|
|
}
|
|
++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);
|
|
}
|
|
|
|
/**
|
|
* void journal_unlock_updates (journal_t* journal) - release barrier
|
|
* @journal: Journal to release the barrier on.
|
|
*
|
|
* Release a transaction barrier obtained with journal_lock_updates().
|
|
*/
|
|
void journal_unlock_updates (journal_t *journal)
|
|
{
|
|
J_ASSERT(journal->j_barrier_count != 0);
|
|
|
|
spin_lock(&journal->j_state_lock);
|
|
--journal->j_barrier_count;
|
|
spin_unlock(&journal->j_state_lock);
|
|
wake_up(&journal->j_wait_transaction_locked);
|
|
}
|
|
|
|
static void warn_dirty_buffer(struct buffer_head *bh)
|
|
{
|
|
char b[BDEVNAME_SIZE];
|
|
|
|
printk(KERN_WARNING
|
|
"JBD: Spotted dirty metadata buffer (dev = %s, blocknr = %llu). "
|
|
"There's a risk of filesystem corruption in case of system "
|
|
"crash.\n",
|
|
bdevname(bh->b_bdev, b), (unsigned long long)bh->b_blocknr);
|
|
}
|
|
|
|
/*
|
|
* 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, "journal_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);
|
|
warn_dirty_buffer(bh);
|
|
}
|
|
/*
|
|
* 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, "Journalling dirty buffer");
|
|
clear_buffer_dirty(bh);
|
|
set_buffer_jbddirty(bh);
|
|
}
|
|
|
|
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 =
|
|
jbd_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);
|
|
JBUFFER_TRACE(jh, "file as BJ_Reserved");
|
|
spin_lock(&journal->j_list_lock);
|
|
__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 = offset_in_page(jh2bh(jh)->b_data);
|
|
source = kmap_atomic(page);
|
|
memcpy(jh->b_frozen_data, source+offset, jh2bh(jh)->b_size);
|
|
kunmap_atomic(source);
|
|
}
|
|
jbd_unlock_bh_state(bh);
|
|
|
|
/*
|
|
* If we are about to journal a buffer, then any revoke pending on it is
|
|
* no longer valid
|
|
*/
|
|
journal_cancel_revoke(handle, jh);
|
|
|
|
out:
|
|
if (unlikely(frozen_buffer)) /* It's usually NULL */
|
|
jbd_free(frozen_buffer, bh->b_size);
|
|
|
|
JBUFFER_TRACE(jh, "exit");
|
|
return error;
|
|
}
|
|
|
|
/**
|
|
* int 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
|
|
*
|
|
* 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 journal_get_write_access(handle_t *handle, struct buffer_head *bh)
|
|
{
|
|
struct journal_head *jh = 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);
|
|
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 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 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 = 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) {
|
|
/*
|
|
* Previous journal_forget() could have left the buffer
|
|
* with jbddirty bit set because it was being committed. When
|
|
* the commit finished, we've filed the buffer for
|
|
* checkpointing and marked it dirty. Now we are reallocating
|
|
* the buffer so the transaction freeing it must have
|
|
* committed and so it's safe to clear the dirty bit.
|
|
*/
|
|
clear_buffer_dirty(jh2bh(jh));
|
|
|
|
/* first access by this transaction */
|
|
jh->b_modified = 0;
|
|
|
|
JBUFFER_TRACE(jh, "file as BJ_Reserved");
|
|
__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");
|
|
journal_cancel_revoke(handle, jh);
|
|
out:
|
|
journal_put_journal_head(jh);
|
|
return err;
|
|
}
|
|
|
|
/**
|
|
* int journal_get_undo_access() - Notify intent to modify metadata with non-rewindable consequences
|
|
* @handle: transaction
|
|
* @bh: buffer to undo
|
|
*
|
|
* 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, 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 journal_get_undo_access(handle_t *handle, struct buffer_head *bh)
|
|
{
|
|
int err;
|
|
struct journal_head *jh = 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 = jbd_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:
|
|
journal_put_journal_head(jh);
|
|
if (unlikely(committed_data))
|
|
jbd_free(committed_data, bh->b_size);
|
|
return err;
|
|
}
|
|
|
|
/**
|
|
* int journal_dirty_data() - mark a buffer as containing dirty data to be flushed
|
|
* @handle: transaction
|
|
* @bh: bufferhead to mark
|
|
*
|
|
* Description:
|
|
* Mark a buffer as containing dirty data which needs to be flushed before
|
|
* we can commit the current transaction.
|
|
*
|
|
* The buffer is placed on the transaction's data list and is marked as
|
|
* belonging to the transaction.
|
|
*
|
|
* Returns error number or 0 on success.
|
|
*
|
|
* journal_dirty_data() can be called via page_launder->ext3_writepage
|
|
* by kswapd.
|
|
*/
|
|
int journal_dirty_data(handle_t *handle, struct buffer_head *bh)
|
|
{
|
|
journal_t *journal = handle->h_transaction->t_journal;
|
|
int need_brelse = 0;
|
|
struct journal_head *jh;
|
|
int ret = 0;
|
|
|
|
if (is_handle_aborted(handle))
|
|
return ret;
|
|
|
|
jh = journal_add_journal_head(bh);
|
|
JBUFFER_TRACE(jh, "entry");
|
|
|
|
/*
|
|
* The buffer could *already* be dirty. Writeout can start
|
|
* at any time.
|
|
*/
|
|
jbd_debug(4, "jh: %p, tid:%d\n", jh, handle->h_transaction->t_tid);
|
|
|
|
/*
|
|
* What if the buffer is already part of a running transaction?
|
|
*
|
|
* There are two cases:
|
|
* 1) It is part of the current running transaction. Refile it,
|
|
* just in case we have allocated it as metadata, deallocated
|
|
* it, then reallocated it as data.
|
|
* 2) It is part of the previous, still-committing transaction.
|
|
* If all we want to do is to guarantee that the buffer will be
|
|
* written to disk before this new transaction commits, then
|
|
* being sure that the *previous* transaction has this same
|
|
* property is sufficient for us! Just leave it on its old
|
|
* transaction.
|
|
*
|
|
* In case (2), the buffer must not already exist as metadata
|
|
* --- that would violate write ordering (a transaction is free
|
|
* to write its data at any point, even before the previous
|
|
* committing transaction has committed). The caller must
|
|
* never, ever allow this to happen: there's nothing we can do
|
|
* about it in this layer.
|
|
*/
|
|
jbd_lock_bh_state(bh);
|
|
spin_lock(&journal->j_list_lock);
|
|
|
|
/* Now that we have bh_state locked, are we really still mapped? */
|
|
if (!buffer_mapped(bh)) {
|
|
JBUFFER_TRACE(jh, "unmapped buffer, bailing out");
|
|
goto no_journal;
|
|
}
|
|
|
|
if (jh->b_transaction) {
|
|
JBUFFER_TRACE(jh, "has transaction");
|
|
if (jh->b_transaction != handle->h_transaction) {
|
|
JBUFFER_TRACE(jh, "belongs to older transaction");
|
|
J_ASSERT_JH(jh, jh->b_transaction ==
|
|
journal->j_committing_transaction);
|
|
|
|
/* @@@ IS THIS TRUE ? */
|
|
/*
|
|
* Not any more. Scenario: someone does a write()
|
|
* in data=journal mode. The buffer's transaction has
|
|
* moved into commit. Then someone does another
|
|
* write() to the file. We do the frozen data copyout
|
|
* and set b_next_transaction to point to j_running_t.
|
|
* And while we're in that state, someone does a
|
|
* writepage() in an attempt to pageout the same area
|
|
* of the file via a shared mapping. At present that
|
|
* calls journal_dirty_data(), and we get right here.
|
|
* It may be too late to journal the data. Simply
|
|
* falling through to the next test will suffice: the
|
|
* data will be dirty and wil be checkpointed. The
|
|
* ordering comments in the next comment block still
|
|
* apply.
|
|
*/
|
|
//J_ASSERT_JH(jh, jh->b_next_transaction == NULL);
|
|
|
|
/*
|
|
* If we're journalling data, and this buffer was
|
|
* subject to a write(), it could be metadata, forget
|
|
* or shadow against the committing transaction. Now,
|
|
* someone has dirtied the same darn page via a mapping
|
|
* and it is being writepage()'d.
|
|
* We *could* just steal the page from commit, with some
|
|
* fancy locking there. Instead, we just skip it -
|
|
* don't tie the page's buffers to the new transaction
|
|
* at all.
|
|
* Implication: if we crash before the writepage() data
|
|
* is written into the filesystem, recovery will replay
|
|
* the write() data.
|
|
*/
|
|
if (jh->b_jlist != BJ_None &&
|
|
jh->b_jlist != BJ_SyncData &&
|
|
jh->b_jlist != BJ_Locked) {
|
|
JBUFFER_TRACE(jh, "Not stealing");
|
|
goto no_journal;
|
|
}
|
|
|
|
/*
|
|
* This buffer may be undergoing writeout in commit. We
|
|
* can't return from here and let the caller dirty it
|
|
* again because that can cause the write-out loop in
|
|
* commit to never terminate.
|
|
*/
|
|
if (buffer_dirty(bh)) {
|
|
get_bh(bh);
|
|
spin_unlock(&journal->j_list_lock);
|
|
jbd_unlock_bh_state(bh);
|
|
need_brelse = 1;
|
|
sync_dirty_buffer(bh);
|
|
jbd_lock_bh_state(bh);
|
|
spin_lock(&journal->j_list_lock);
|
|
/* Since we dropped the lock... */
|
|
if (!buffer_mapped(bh)) {
|
|
JBUFFER_TRACE(jh, "buffer got unmapped");
|
|
goto no_journal;
|
|
}
|
|
/* The buffer may become locked again at any
|
|
time if it is redirtied */
|
|
}
|
|
|
|
/*
|
|
* We cannot remove the buffer with io error from the
|
|
* committing transaction, because otherwise it would
|
|
* miss the error and the commit would not abort.
|
|
*/
|
|
if (unlikely(!buffer_uptodate(bh))) {
|
|
ret = -EIO;
|
|
goto no_journal;
|
|
}
|
|
/* We might have slept so buffer could be refiled now */
|
|
if (jh->b_transaction != NULL &&
|
|
jh->b_transaction != handle->h_transaction) {
|
|
JBUFFER_TRACE(jh, "unfile from commit");
|
|
__journal_temp_unlink_buffer(jh);
|
|
/* It still points to the committing
|
|
* transaction; move it to this one so
|
|
* that the refile assert checks are
|
|
* happy. */
|
|
jh->b_transaction = handle->h_transaction;
|
|
}
|
|
/* The buffer will be refiled below */
|
|
|
|
}
|
|
/*
|
|
* Special case --- the buffer might actually have been
|
|
* allocated and then immediately deallocated in the previous,
|
|
* committing transaction, so might still be left on that
|
|
* transaction's metadata lists.
|
|
*/
|
|
if (jh->b_jlist != BJ_SyncData && jh->b_jlist != BJ_Locked) {
|
|
JBUFFER_TRACE(jh, "not on correct data list: unfile");
|
|
J_ASSERT_JH(jh, jh->b_jlist != BJ_Shadow);
|
|
JBUFFER_TRACE(jh, "file as data");
|
|
__journal_file_buffer(jh, handle->h_transaction,
|
|
BJ_SyncData);
|
|
}
|
|
} else {
|
|
JBUFFER_TRACE(jh, "not on a transaction");
|
|
__journal_file_buffer(jh, handle->h_transaction, BJ_SyncData);
|
|
}
|
|
no_journal:
|
|
spin_unlock(&journal->j_list_lock);
|
|
jbd_unlock_bh_state(bh);
|
|
if (need_brelse) {
|
|
BUFFER_TRACE(bh, "brelse");
|
|
__brelse(bh);
|
|
}
|
|
JBUFFER_TRACE(jh, "exit");
|
|
journal_put_journal_head(jh);
|
|
return ret;
|
|
}
|
|
|
|
/**
|
|
* int 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 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);
|
|
__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;
|
|
}
|
|
|
|
/*
|
|
* 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
|
|
journal_release_buffer(handle_t *handle, struct buffer_head *bh)
|
|
{
|
|
BUFFER_TRACE(bh, "entry");
|
|
}
|
|
|
|
/**
|
|
* void 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 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 whether 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) {
|
|
__journal_temp_unlink_buffer(jh);
|
|
__journal_file_buffer(jh, transaction, BJ_Forget);
|
|
} else {
|
|
__journal_unfile_buffer(jh);
|
|
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 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.
|
|
*
|
|
* 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 journal_abort has been executed since the
|
|
* transaction began.
|
|
*/
|
|
int 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 = min_t(u64, commit_time,
|
|
1000*jiffies_to_usecs(1));
|
|
|
|
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 */
|
|
__log_start_commit(journal, transaction->t_tid);
|
|
spin_unlock(&journal->j_state_lock);
|
|
|
|
/*
|
|
* Special case: JFS_SYNC synchronous updates require us
|
|
* to wait for the commit to complete.
|
|
*/
|
|
if (handle->h_sync && !(current->flags & PF_MEMALLOC))
|
|
err = 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);
|
|
|
|
jbd_free_handle(handle);
|
|
return err;
|
|
}
|
|
|
|
/**
|
|
* int 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 journal_force_commit(journal_t *journal)
|
|
{
|
|
handle_t *handle;
|
|
int ret;
|
|
|
|
handle = journal_start(journal, 1);
|
|
if (IS_ERR(handle)) {
|
|
ret = PTR_ERR(handle);
|
|
} else {
|
|
handle->h_sync = 1;
|
|
ret = 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_sync_datalist, 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 thee 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.
|
|
*/
|
|
static void __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_SyncData:
|
|
list = &transaction->t_sync_datalist;
|
|
break;
|
|
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;
|
|
case BJ_Locked:
|
|
list = &transaction->t_locked_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 */
|
|
}
|
|
|
|
/*
|
|
* Remove buffer from all transactions.
|
|
*
|
|
* Called with bh_state lock and j_list_lock
|
|
*
|
|
* jh and bh may be already freed when this function returns.
|
|
*/
|
|
void __journal_unfile_buffer(struct journal_head *jh)
|
|
{
|
|
__journal_temp_unlink_buffer(jh);
|
|
jh->b_transaction = NULL;
|
|
journal_put_journal_head(jh);
|
|
}
|
|
|
|
void journal_unfile_buffer(journal_t *journal, struct journal_head *jh)
|
|
{
|
|
struct buffer_head *bh = jh2bh(jh);
|
|
|
|
/* Get reference so that buffer cannot be freed before we unlock it */
|
|
get_bh(bh);
|
|
jbd_lock_bh_state(bh);
|
|
spin_lock(&journal->j_list_lock);
|
|
__journal_unfile_buffer(jh);
|
|
spin_unlock(&journal->j_list_lock);
|
|
jbd_unlock_bh_state(bh);
|
|
__brelse(bh);
|
|
}
|
|
|
|
/*
|
|
* Called from 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_transaction != NULL && jh->b_cp_transaction == NULL) {
|
|
if (jh->b_jlist == BJ_SyncData || jh->b_jlist == BJ_Locked) {
|
|
/* A written-back ordered data buffer */
|
|
JBUFFER_TRACE(jh, "release data");
|
|
__journal_unfile_buffer(jh);
|
|
}
|
|
} else 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");
|
|
__journal_remove_checkpoint(jh);
|
|
}
|
|
}
|
|
spin_unlock(&journal->j_list_lock);
|
|
out:
|
|
return;
|
|
}
|
|
|
|
/**
|
|
* int 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 __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 journal_dirty_data on this
|
|
* buffer. So we need to lock against that. 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 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
|
|
* journal_put_journal_head().
|
|
*/
|
|
jh = journal_grab_journal_head(bh);
|
|
if (!jh)
|
|
continue;
|
|
|
|
jbd_lock_bh_state(bh);
|
|
__journal_try_to_free_buffer(journal, bh);
|
|
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);
|
|
|
|
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);
|
|
|
|
if (jh->b_cp_transaction) {
|
|
JBUFFER_TRACE(jh, "on running+cp transaction");
|
|
__journal_temp_unlink_buffer(jh);
|
|
/*
|
|
* We don't want to write the buffer anymore, clear the
|
|
* bit so that we don't confuse checks in
|
|
* __journal_file_buffer
|
|
*/
|
|
clear_buffer_dirty(bh);
|
|
__journal_file_buffer(jh, transaction, BJ_Forget);
|
|
may_free = 0;
|
|
} else {
|
|
JBUFFER_TRACE(jh, "on running transaction");
|
|
__journal_unfile_buffer(jh);
|
|
}
|
|
return may_free;
|
|
}
|
|
|
|
/*
|
|
* 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,
|
|
int partial_page)
|
|
{
|
|
transaction_t *transaction;
|
|
struct journal_head *jh;
|
|
int may_free = 1;
|
|
|
|
BUFFER_TRACE(bh, "entry");
|
|
|
|
retry:
|
|
/*
|
|
* 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;
|
|
|
|
spin_lock(&journal->j_state_lock);
|
|
jbd_lock_bh_state(bh);
|
|
spin_lock(&journal->j_list_lock);
|
|
|
|
jh = journal_grab_journal_head(bh);
|
|
if (!jh)
|
|
goto zap_buffer_no_jh;
|
|
|
|
/*
|
|
* We cannot remove the buffer from checkpoint lists until the
|
|
* transaction adding inode to orphan list (let's call it T)
|
|
* is committed. Otherwise if the transaction changing the
|
|
* buffer would be cleaned from the journal before T is
|
|
* committed, a crash will cause that the correct contents of
|
|
* the buffer will be lost. On the other hand we have to
|
|
* clear the buffer dirty bit at latest at the moment when the
|
|
* transaction marking the buffer as freed in the filesystem
|
|
* structures is committed because from that moment on the
|
|
* block can be reallocated and used by a different page.
|
|
* Since the block hasn't been freed yet but the inode has
|
|
* already been added to orphan list, it is safe for us to add
|
|
* the buffer to BJ_Forget list of the newest transaction.
|
|
*
|
|
* Also we have to clear buffer_mapped flag of a truncated buffer
|
|
* because the buffer_head may be attached to the page straddling
|
|
* i_size (can happen only when blocksize < pagesize) and thus the
|
|
* buffer_head can be reused when the file is extended again. So we end
|
|
* up keeping around invalidated buffers attached to transactions'
|
|
* BJ_Forget list just to stop checkpointing code from cleaning up
|
|
* the transaction this buffer was modified in.
|
|
*/
|
|
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");
|
|
may_free = __dispose_buffer(jh,
|
|
journal->j_running_transaction);
|
|
goto zap_buffer;
|
|
} 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");
|
|
may_free = __dispose_buffer(jh,
|
|
journal->j_committing_transaction);
|
|
goto zap_buffer;
|
|
} 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 (jh->b_jlist == BJ_Locked) {
|
|
/*
|
|
* The buffer is on the committing transaction's locked
|
|
* list. We have the buffer locked, so I/O has
|
|
* completed. So we can nail the buffer now.
|
|
*/
|
|
may_free = __dispose_buffer(jh, transaction);
|
|
goto zap_buffer;
|
|
}
|
|
/*
|
|
* The buffer is committing, we simply cannot touch
|
|
* it. If the page is straddling i_size we have to wait
|
|
* for commit and try again.
|
|
*/
|
|
if (partial_page) {
|
|
tid_t tid = journal->j_committing_transaction->t_tid;
|
|
|
|
journal_put_journal_head(jh);
|
|
spin_unlock(&journal->j_list_lock);
|
|
jbd_unlock_bh_state(bh);
|
|
spin_unlock(&journal->j_state_lock);
|
|
unlock_buffer(bh);
|
|
log_wait_commit(journal, tid);
|
|
lock_buffer(bh);
|
|
goto retry;
|
|
}
|
|
/*
|
|
* OK, buffer won't be reachable after truncate. We just set
|
|
* j_next_transaction to the running transaction (if there is
|
|
* one) and mark buffer as freed so that commit code knows it
|
|
* should clear dirty bits when it is done with the buffer.
|
|
*/
|
|
set_buffer_freed(bh);
|
|
if (journal->j_running_transaction && buffer_jbddirty(bh))
|
|
jh->b_next_transaction = journal->j_running_transaction;
|
|
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:
|
|
/*
|
|
* This is tricky. Although the buffer is truncated, it may be reused
|
|
* if blocksize < pagesize and it is attached to the page straddling
|
|
* EOF. Since the buffer might have been added to BJ_Forget list of the
|
|
* running transaction, journal_get_write_access() won't clear
|
|
* b_modified and credit accounting gets confused. So clear b_modified
|
|
* here. */
|
|
jh->b_modified = 0;
|
|
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 journal_invalidatepage() - invalidate a journal page
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* @journal: journal to use for flush
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* @page: page to flush
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* @offset: length of page to invalidate.
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*
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* Reap page buffers containing data after offset in page.
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*/
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void journal_invalidatepage(journal_t *journal,
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struct page *page,
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unsigned long offset)
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{
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struct buffer_head *head, *bh, *next;
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unsigned int curr_off = 0;
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int may_free = 1;
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if (!PageLocked(page))
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BUG();
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if (!page_has_buffers(page))
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return;
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/* We will potentially be playing with lists other than just the
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* data lists (especially for journaled data mode), so be
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* cautious in our locking. */
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head = bh = page_buffers(page);
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do {
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unsigned int next_off = curr_off + bh->b_size;
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next = bh->b_this_page;
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if (offset <= curr_off) {
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/* This block is wholly outside the truncation point */
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lock_buffer(bh);
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may_free &= journal_unmap_buffer(journal, bh,
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offset > 0);
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unlock_buffer(bh);
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}
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curr_off = next_off;
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bh = next;
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} while (bh != head);
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if (!offset) {
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if (may_free && try_to_free_buffers(page))
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J_ASSERT(!page_has_buffers(page));
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}
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}
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/*
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* File a buffer on the given transaction list.
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*/
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void __journal_file_buffer(struct journal_head *jh,
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transaction_t *transaction, int jlist)
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{
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struct journal_head **list = NULL;
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int was_dirty = 0;
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struct buffer_head *bh = jh2bh(jh);
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J_ASSERT_JH(jh, jbd_is_locked_bh_state(bh));
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assert_spin_locked(&transaction->t_journal->j_list_lock);
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J_ASSERT_JH(jh, jh->b_jlist < BJ_Types);
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J_ASSERT_JH(jh, jh->b_transaction == transaction ||
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jh->b_transaction == NULL);
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if (jh->b_transaction && jh->b_jlist == jlist)
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return;
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if (jlist == BJ_Metadata || jlist == BJ_Reserved ||
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jlist == BJ_Shadow || jlist == BJ_Forget) {
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/*
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* For metadata buffers, we track dirty bit in buffer_jbddirty
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* instead of buffer_dirty. We should not see a dirty bit set
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* here because we clear it in do_get_write_access but e.g.
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* tune2fs can modify the sb and set the dirty bit at any time
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* so we try to gracefully handle that.
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*/
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if (buffer_dirty(bh))
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warn_dirty_buffer(bh);
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if (test_clear_buffer_dirty(bh) ||
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test_clear_buffer_jbddirty(bh))
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was_dirty = 1;
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}
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|
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if (jh->b_transaction)
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__journal_temp_unlink_buffer(jh);
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else
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journal_grab_journal_head(bh);
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jh->b_transaction = transaction;
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|
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switch (jlist) {
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case BJ_None:
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J_ASSERT_JH(jh, !jh->b_committed_data);
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J_ASSERT_JH(jh, !jh->b_frozen_data);
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return;
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case BJ_SyncData:
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list = &transaction->t_sync_datalist;
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break;
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case BJ_Metadata:
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transaction->t_nr_buffers++;
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list = &transaction->t_buffers;
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break;
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case BJ_Forget:
|
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list = &transaction->t_forget;
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break;
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case BJ_IO:
|
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list = &transaction->t_iobuf_list;
|
|
break;
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|
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;
|
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case BJ_Locked:
|
|
list = &transaction->t_locked_list;
|
|
break;
|
|
}
|
|
|
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__blist_add_buffer(list, jh);
|
|
jh->b_jlist = jlist;
|
|
|
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if (was_dirty)
|
|
set_buffer_jbddirty(bh);
|
|
}
|
|
|
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void journal_file_buffer(struct journal_head *jh,
|
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transaction_t *transaction, int jlist)
|
|
{
|
|
jbd_lock_bh_state(jh2bh(jh));
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spin_lock(&transaction->t_journal->j_list_lock);
|
|
__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 j_list_lock
|
|
* Called under jbd_lock_bh_state(jh2bh(jh))
|
|
*
|
|
* jh and bh may be already free when this function returns
|
|
*/
|
|
void __journal_refile_buffer(struct journal_head *jh)
|
|
{
|
|
int was_dirty, jlist;
|
|
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) {
|
|
__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);
|
|
__journal_temp_unlink_buffer(jh);
|
|
/*
|
|
* We set b_transaction here because b_next_transaction will inherit
|
|
* our jh reference and thus __journal_file_buffer() must not take a
|
|
* new one.
|
|
*/
|
|
jh->b_transaction = jh->b_next_transaction;
|
|
jh->b_next_transaction = NULL;
|
|
if (buffer_freed(bh))
|
|
jlist = BJ_Forget;
|
|
else if (jh->b_modified)
|
|
jlist = BJ_Metadata;
|
|
else
|
|
jlist = BJ_Reserved;
|
|
__journal_file_buffer(jh, jh->b_transaction, jlist);
|
|
J_ASSERT_JH(jh, jh->b_transaction->t_state == T_RUNNING);
|
|
|
|
if (was_dirty)
|
|
set_buffer_jbddirty(bh);
|
|
}
|
|
|
|
/*
|
|
* __journal_refile_buffer() with necessary locking added. We take our bh
|
|
* reference so that we can safely unlock bh.
|
|
*
|
|
* The jh and bh may be freed by this call.
|
|
*/
|
|
void journal_refile_buffer(journal_t *journal, struct journal_head *jh)
|
|
{
|
|
struct buffer_head *bh = jh2bh(jh);
|
|
|
|
/* Get reference so that buffer cannot be freed before we unlock it */
|
|
get_bh(bh);
|
|
jbd_lock_bh_state(bh);
|
|
spin_lock(&journal->j_list_lock);
|
|
__journal_refile_buffer(jh);
|
|
jbd_unlock_bh_state(bh);
|
|
spin_unlock(&journal->j_list_lock);
|
|
__brelse(bh);
|
|
}
|