Minki/linux
1
0
Fork 1
mirror of https://github.com/torvalds/linux.git synced 2024-11-11 14:42:24 +00:00
Code Issues Packages Projects Releases Wiki Activity
4550dd6c6b
linux/fs/jbd2/journal.c
Darrick J. Wong 18a6ea1e5c jbd2: Fix endian mixing problems in the checksumming code 
In the jbd2 checksumming code, explicitly declare separate variables with
endianness information so that we don't get confused and screw things up again.
Also fixes sparse warnings.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
2013-08-28 14:59:58 -04:00

2658 lines
74 KiB
C
Raw Blame History

/*
* linux/fs/jbd2/journal.c
*
* Written by Stephen C. Tweedie <sct@redhat.com>, 1998
*
* Copyright 1998 Red Hat corp --- All Rights Reserved
*
* This file is part of the Linux kernel and is made available under
* the terms of the GNU General Public License, version 2, or at your
* option, any later version, incorporated herein by reference.
*
* Generic filesystem journal-writing code; part of the ext2fs
* journaling system.
*
* This file manages journals: areas of disk reserved for logging
* transactional updates. This includes the kernel journaling thread
* which is responsible for scheduling updates to the log.
*
* We do not actually manage the physical storage of the journal in this
* file: that is left to a per-journal policy function, which allows us
* to store the journal within a filesystem-specified area for ext2
* journaling (ext2 can use a reserved inode for storing the log).
*/
#include <linux/module.h>
#include <linux/time.h>
#include <linux/fs.h>
#include <linux/jbd2.h>
#include <linux/errno.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/mm.h>
#include <linux/freezer.h>
#include <linux/pagemap.h>
#include <linux/kthread.h>
#include <linux/poison.h>
#include <linux/proc_fs.h>
#include <linux/seq_file.h>
#include <linux/math64.h>
#include <linux/hash.h>
#include <linux/log2.h>
#include <linux/vmalloc.h>
#include <linux/backing-dev.h>
#include <linux/bitops.h>
#include <linux/ratelimit.h>
#define CREATE_TRACE_POINTS
#include <trace/events/jbd2.h>
#include <asm/uaccess.h>
#include <asm/page.h>
#ifdef CONFIG_JBD2_DEBUG
ushort jbd2_journal_enable_debug __read_mostly;
EXPORT_SYMBOL(jbd2_journal_enable_debug);
module_param_named(jbd2_debug, jbd2_journal_enable_debug, ushort, 0644);
MODULE_PARM_DESC(jbd2_debug, "Debugging level for jbd2");
#endif
EXPORT_SYMBOL(jbd2_journal_extend);
EXPORT_SYMBOL(jbd2_journal_stop);
EXPORT_SYMBOL(jbd2_journal_lock_updates);
EXPORT_SYMBOL(jbd2_journal_unlock_updates);
EXPORT_SYMBOL(jbd2_journal_get_write_access);
EXPORT_SYMBOL(jbd2_journal_get_create_access);
EXPORT_SYMBOL(jbd2_journal_get_undo_access);
EXPORT_SYMBOL(jbd2_journal_set_triggers);
EXPORT_SYMBOL(jbd2_journal_dirty_metadata);
EXPORT_SYMBOL(jbd2_journal_forget);
#if 0
EXPORT_SYMBOL(journal_sync_buffer);
#endif
EXPORT_SYMBOL(jbd2_journal_flush);
EXPORT_SYMBOL(jbd2_journal_revoke);
EXPORT_SYMBOL(jbd2_journal_init_dev);
EXPORT_SYMBOL(jbd2_journal_init_inode);
EXPORT_SYMBOL(jbd2_journal_check_used_features);
EXPORT_SYMBOL(jbd2_journal_check_available_features);
EXPORT_SYMBOL(jbd2_journal_set_features);
EXPORT_SYMBOL(jbd2_journal_load);
EXPORT_SYMBOL(jbd2_journal_destroy);
EXPORT_SYMBOL(jbd2_journal_abort);
EXPORT_SYMBOL(jbd2_journal_errno);
EXPORT_SYMBOL(jbd2_journal_ack_err);
EXPORT_SYMBOL(jbd2_journal_clear_err);
EXPORT_SYMBOL(jbd2_log_wait_commit);
EXPORT_SYMBOL(jbd2_log_start_commit);
EXPORT_SYMBOL(jbd2_journal_start_commit);
EXPORT_SYMBOL(jbd2_journal_force_commit_nested);
EXPORT_SYMBOL(jbd2_journal_wipe);
EXPORT_SYMBOL(jbd2_journal_blocks_per_page);
EXPORT_SYMBOL(jbd2_journal_invalidatepage);
EXPORT_SYMBOL(jbd2_journal_try_to_free_buffers);
EXPORT_SYMBOL(jbd2_journal_force_commit);
EXPORT_SYMBOL(jbd2_journal_file_inode);
EXPORT_SYMBOL(jbd2_journal_init_jbd_inode);
EXPORT_SYMBOL(jbd2_journal_release_jbd_inode);
EXPORT_SYMBOL(jbd2_journal_begin_ordered_truncate);
EXPORT_SYMBOL(jbd2_inode_cache);
static void __journal_abort_soft (journal_t *journal, int errno);
static int jbd2_journal_create_slab(size_t slab_size);
#ifdef CONFIG_JBD2_DEBUG
void __jbd2_debug(int level, const char *file, const char *func,
unsigned int line, const char *fmt, ...)
{
struct va_format vaf;
va_list args;
if (level > jbd2_journal_enable_debug)
return;
va_start(args, fmt);
vaf.fmt = fmt;
vaf.va = &args;
printk(KERN_DEBUG "%s: (%s, %u): %pV\n", file, func, line, &vaf);
va_end(args);
}
EXPORT_SYMBOL(__jbd2_debug);
#endif
/* Checksumming functions */
int jbd2_verify_csum_type(journal_t *j, journal_superblock_t *sb)
{
if (!JBD2_HAS_INCOMPAT_FEATURE(j, JBD2_FEATURE_INCOMPAT_CSUM_V2))
return 1;
return sb->s_checksum_type == JBD2_CRC32C_CHKSUM;
}
static __be32 jbd2_superblock_csum(journal_t *j, journal_superblock_t *sb)
{
__u32 csum;
__be32 old_csum;
old_csum = sb->s_checksum;
sb->s_checksum = 0;
csum = jbd2_chksum(j, ~0, (char *)sb, sizeof(journal_superblock_t));
sb->s_checksum = old_csum;
return cpu_to_be32(csum);
}
int jbd2_superblock_csum_verify(journal_t *j, journal_superblock_t *sb)
{
if (!JBD2_HAS_INCOMPAT_FEATURE(j, JBD2_FEATURE_INCOMPAT_CSUM_V2))
return 1;
return sb->s_checksum == jbd2_superblock_csum(j, sb);
}
void jbd2_superblock_csum_set(journal_t *j, journal_superblock_t *sb)
{
if (!JBD2_HAS_INCOMPAT_FEATURE(j, JBD2_FEATURE_INCOMPAT_CSUM_V2))
return;
sb->s_checksum = jbd2_superblock_csum(j, sb);
}
/*
* Helper function used to manage commit timeouts
*/
static void commit_timeout(unsigned long __data)
{
struct task_struct * p = (struct task_struct *) __data;
wake_up_process(p);
}
/*
* kjournald2: The main thread function used to manage a logging device
* journal.
*
* This kernel thread is responsible for two things:
*
* 1) COMMIT: Every so often we need to commit the current state of the
* filesystem to disk. The journal thread is responsible for writing
* all of the metadata buffers to disk.
*
* 2) CHECKPOINT: We cannot reuse a used section of the log file until all
* of the data in that part of the log has been rewritten elsewhere on
* the disk. Flushing these old buffers to reclaim space in the log is
* known as checkpointing, and this thread is responsible for that job.
*/
static int kjournald2(void *arg)
{
journal_t *journal = arg;
transaction_t *transaction;
/*
* Set up an interval timer which can be used to trigger a commit wakeup
* after the commit interval expires
*/
setup_timer(&journal->j_commit_timer, commit_timeout,
(unsigned long)current);
set_freezable();
/* Record that the journal thread is running */
journal->j_task = current;
wake_up(&journal->j_wait_done_commit);
/*
* And now, wait forever for commit wakeup events.
*/
write_lock(&journal->j_state_lock);
loop:
if (journal->j_flags & JBD2_UNMOUNT)
goto end_loop;
jbd_debug(1, "commit_sequence=%d, commit_request=%d\n",
journal->j_commit_sequence, journal->j_commit_request);
if (journal->j_commit_sequence != journal->j_commit_request) {
jbd_debug(1, "OK, requests differ\n");
write_unlock(&journal->j_state_lock);
del_timer_sync(&journal->j_commit_timer);
jbd2_journal_commit_transaction(journal);
write_lock(&journal->j_state_lock);
goto loop;
}
wake_up(&journal->j_wait_done_commit);
if (freezing(current)) {
/*
* The simpler the better. Flushing journal isn't a
* good idea, because that depends on threads that may
* be already stopped.
*/
jbd_debug(1, "Now suspending kjournald2\n");
write_unlock(&journal->j_state_lock);
try_to_freeze();
write_lock(&journal->j_state_lock);
} else {
/*
* We assume on resume that commits are already there,
* so we don't sleep
*/
DEFINE_WAIT(wait);
int should_sleep = 1;
prepare_to_wait(&journal->j_wait_commit, &wait,
TASK_INTERRUPTIBLE);
if (journal->j_commit_sequence != journal->j_commit_request)
should_sleep = 0;
transaction = journal->j_running_transaction;
if (transaction && time_after_eq(jiffies,
transaction->t_expires))
should_sleep = 0;
if (journal->j_flags & JBD2_UNMOUNT)
should_sleep = 0;
if (should_sleep) {
write_unlock(&journal->j_state_lock);
schedule();
write_lock(&journal->j_state_lock);
}
finish_wait(&journal->j_wait_commit, &wait);
}
jbd_debug(1, "kjournald2 wakes\n");
/*
* Were we woken up by a commit wakeup event?
*/
transaction = journal->j_running_transaction;
if (transaction && time_after_eq(jiffies, transaction->t_expires)) {
journal->j_commit_request = transaction->t_tid;
jbd_debug(1, "woke because of timeout\n");
}
goto loop;
end_loop:
write_unlock(&journal->j_state_lock);
del_timer_sync(&journal->j_commit_timer);
journal->j_task = NULL;
wake_up(&journal->j_wait_done_commit);
jbd_debug(1, "Journal thread exiting.\n");
return 0;
}
static int jbd2_journal_start_thread(journal_t *journal)
{
struct task_struct *t;
t = kthread_run(kjournald2, journal, "jbd2/%s",
journal->j_devname);
if (IS_ERR(t))
return PTR_ERR(t);
wait_event(journal->j_wait_done_commit, journal->j_task != NULL);
return 0;
}
static void journal_kill_thread(journal_t *journal)
{
write_lock(&journal->j_state_lock);
journal->j_flags |= JBD2_UNMOUNT;
while (journal->j_task) {
wake_up(&journal->j_wait_commit);
write_unlock(&journal->j_state_lock);
wait_event(journal->j_wait_done_commit, journal->j_task == NULL);
write_lock(&journal->j_state_lock);
}
write_unlock(&journal->j_state_lock);
}
/*
* jbd2_journal_write_metadata_buffer: write a metadata buffer to the journal.
*
* Writes a metadata buffer to a given disk block. The actual IO is not
* performed but a new buffer_head is constructed which labels the data
* to be written with the correct destination disk block.
*
* Any magic-number escaping which needs to be done will cause a
* copy-out here. If the buffer happens to start with the
* JBD2_MAGIC_NUMBER, then we can't write it to the log directly: the
* magic number is only written to the log for descripter blocks. In
* this case, we copy the data and replace the first word with 0, and we
* return a result code which indicates that this buffer needs to be
* marked as an escaped buffer in the corresponding log descriptor
* block. The missing word can then be restored when the block is read
* during recovery.
*
* If the source buffer has already been modified by a new transaction
* since we took the last commit snapshot, we use the frozen copy of
* that data for IO. If we end up using the existing buffer_head's data
* for the write, then we have to make sure nobody modifies it while the
* IO is in progress. do_get_write_access() handles this.
*
* The function returns a pointer to the buffer_head to be used for IO.
*
*
* Return value:
* <0: Error
* >=0: Finished OK
*
* On success:
* Bit 0 set == escape performed on the data
* Bit 1 set == buffer copy-out performed (kfree the data after IO)
*/
int jbd2_journal_write_metadata_buffer(transaction_t *transaction,
struct journal_head *jh_in,
struct buffer_head **bh_out,
sector_t blocknr)
{
int need_copy_out = 0;
int done_copy_out = 0;
int do_escape = 0;
char *mapped_data;
struct buffer_head *new_bh;
struct page *new_page;
unsigned int new_offset;
struct buffer_head *bh_in = jh2bh(jh_in);
journal_t *journal = transaction->t_journal;
/*
* The buffer really shouldn't be locked: only the current committing
* transaction is allowed to write it, so nobody else is allowed
* to do any IO.
*
* akpm: except if we're journalling data, and write() output is
* also part of a shared mapping, and another thread has
* decided to launch a writepage() against this buffer.
*/
J_ASSERT_BH(bh_in, buffer_jbddirty(bh_in));
retry_alloc:
new_bh = alloc_buffer_head(GFP_NOFS);
if (!new_bh) {
/*
* Failure is not an option, but __GFP_NOFAIL is going
* away; so we retry ourselves here.
*/
congestion_wait(BLK_RW_ASYNC, HZ/50);
goto retry_alloc;
}
/* keep subsequent assertions sane */
atomic_set(&new_bh->b_count, 1);
jbd_lock_bh_state(bh_in);
repeat:
/*
* If a new transaction has already done a buffer copy-out, then
* we use that version of the data for the commit.
*/
if (jh_in->b_frozen_data) {
done_copy_out = 1;
new_page = virt_to_page(jh_in->b_frozen_data);
new_offset = offset_in_page(jh_in->b_frozen_data);
} else {
new_page = jh2bh(jh_in)->b_page;
new_offset = offset_in_page(jh2bh(jh_in)->b_data);
}
mapped_data = kmap_atomic(new_page);
/*
* Fire data frozen trigger if data already wasn't frozen. Do this
* before checking for escaping, as the trigger may modify the magic
* offset. If a copy-out happens afterwards, it will have the correct
* data in the buffer.
*/
if (!done_copy_out)
jbd2_buffer_frozen_trigger(jh_in, mapped_data + new_offset,
jh_in->b_triggers);
/*
* Check for escaping
*/
if (*((__be32 *)(mapped_data + new_offset)) ==
cpu_to_be32(JBD2_MAGIC_NUMBER)) {
need_copy_out = 1;
do_escape = 1;
}
kunmap_atomic(mapped_data);
/*
* Do we need to do a data copy?
*/
if (need_copy_out && !done_copy_out) {
char *tmp;
jbd_unlock_bh_state(bh_in);
tmp = jbd2_alloc(bh_in->b_size, GFP_NOFS);
if (!tmp) {
brelse(new_bh);
return -ENOMEM;
}
jbd_lock_bh_state(bh_in);
if (jh_in->b_frozen_data) {
jbd2_free(tmp, bh_in->b_size);
goto repeat;
}
jh_in->b_frozen_data = tmp;
mapped_data = kmap_atomic(new_page);
memcpy(tmp, mapped_data + new_offset, bh_in->b_size);
kunmap_atomic(mapped_data);
new_page = virt_to_page(tmp);
new_offset = offset_in_page(tmp);
done_copy_out = 1;
/*
* This isn't strictly necessary, as we're using frozen
* data for the escaping, but it keeps consistency with
* b_frozen_data usage.
*/
jh_in->b_frozen_triggers = jh_in->b_triggers;
}
/*
* Did we need to do an escaping? Now we've done all the
* copying, we can finally do so.
*/
if (do_escape) {
mapped_data = kmap_atomic(new_page);
*((unsigned int *)(mapped_data + new_offset)) = 0;
kunmap_atomic(mapped_data);
}
set_bh_page(new_bh, new_page, new_offset);
new_bh->b_size = bh_in->b_size;
new_bh->b_bdev = journal->j_dev;
new_bh->b_blocknr = blocknr;
new_bh->b_private = bh_in;
set_buffer_mapped(new_bh);
set_buffer_dirty(new_bh);
*bh_out = new_bh;
/*
* The to-be-written buffer needs to get moved to the io queue,
* and the original buffer whose contents we are shadowing or
* copying is moved to the transaction's shadow queue.
*/
JBUFFER_TRACE(jh_in, "file as BJ_Shadow");
spin_lock(&journal->j_list_lock);
__jbd2_journal_file_buffer(jh_in, transaction, BJ_Shadow);
spin_unlock(&journal->j_list_lock);
set_buffer_shadow(bh_in);
jbd_unlock_bh_state(bh_in);
return do_escape | (done_copy_out << 1);
}
/*
* Allocation code for the journal file. Manage the space left in the
* journal, so that we can begin checkpointing when appropriate.
*/
/*
* Called with j_state_lock locked for writing.
* Returns true if a transaction commit was started.
*/
int __jbd2_log_start_commit(journal_t *journal, tid_t target)
{
/* Return if the txn has already requested to be committed */
if (journal->j_commit_request == target)
return 0;
/*
* The only transaction we can possibly wait upon is the
* currently running transaction (if it exists). Otherwise,
* the target tid must be an old one.
*/
if (journal->j_running_transaction &&
journal->j_running_transaction->t_tid == target) {
/*
* We want a new commit: OK, mark the request and wakeup the
* commit thread. We do _not_ do the commit ourselves.
*/
journal->j_commit_request = target;
jbd_debug(1, "JBD2: requesting commit %d/%d\n",
journal->j_commit_request,
journal->j_commit_sequence);
journal->j_running_transaction->t_requested = jiffies;
wake_up(&journal->j_wait_commit);
return 1;
} else if (!tid_geq(journal->j_commit_request, target))
/* This should never happen, but if it does, preserve
the evidence before kjournald goes into a loop and
increments j_commit_sequence beyond all recognition. */
WARN_ONCE(1, "JBD2: bad log_start_commit: %u %u %u %u\n",
journal->j_commit_request,
journal->j_commit_sequence,
target, journal->j_running_transaction ?
journal->j_running_transaction->t_tid : 0);
return 0;
}
int jbd2_log_start_commit(journal_t *journal, tid_t tid)
{
int ret;
write_lock(&journal->j_state_lock);
ret = __jbd2_log_start_commit(journal, tid);
write_unlock(&journal->j_state_lock);
return ret;
}
/*
* Force and wait any uncommitted transactions. We can only force the running
* transaction if we don't have an active handle, otherwise, we will deadlock.
* Returns: <0 in case of error,
* 0 if nothing to commit,
* 1 if transaction was successfully committed.
*/
static int __jbd2_journal_force_commit(journal_t *journal)
{
transaction_t *transaction = NULL;
tid_t tid;
int need_to_start = 0, ret = 0;
read_lock(&journal->j_state_lock);
if (journal->j_running_transaction && !current->journal_info) {
transaction = journal->j_running_transaction;
if (!tid_geq(journal->j_commit_request, transaction->t_tid))
need_to_start = 1;
} else if (journal->j_committing_transaction)
transaction = journal->j_committing_transaction;
if (!transaction) {
/* Nothing to commit */
read_unlock(&journal->j_state_lock);
return 0;
}
tid = transaction->t_tid;
read_unlock(&journal->j_state_lock);
if (need_to_start)
jbd2_log_start_commit(journal, tid);
ret = jbd2_log_wait_commit(journal, tid);
if (!ret)
ret = 1;
return ret;
}
/**
* Force and wait upon a commit if the calling process is not within
* transaction. This is used for forcing out undo-protected data which contains
* bitmaps, when the fs is running out of space.
*
* @journal: journal to force
* Returns true if progress was made.
*/
int jbd2_journal_force_commit_nested(journal_t *journal)
{
int ret;
ret = __jbd2_journal_force_commit(journal);
return ret > 0;
}
/**
* int journal_force_commit() - force any uncommitted transactions
* @journal: journal to force
*
* Caller want unconditional commit. We can only force the running transaction
* if we don't have an active handle, otherwise, we will deadlock.
*/
int jbd2_journal_force_commit(journal_t *journal)
{
int ret;
J_ASSERT(!current->journal_info);
ret = __jbd2_journal_force_commit(journal);
if (ret > 0)
ret = 0;
return ret;
}
/*
* Start a commit of the current running transaction (if any). Returns true
* if a transaction is going to be committed (or is currently already
* committing), and fills its tid in at *ptid
*/
int jbd2_journal_start_commit(journal_t *journal, tid_t *ptid)
{
int ret = 0;
write_lock(&journal->j_state_lock);
if (journal->j_running_transaction) {
tid_t tid = journal->j_running_transaction->t_tid;
__jbd2_log_start_commit(journal, tid);
/* There's a running transaction and we've just made sure
* it's commit has been scheduled. */
if (ptid)
*ptid = tid;
ret = 1;
} else if (journal->j_committing_transaction) {
/*
* If commit has been started, then we have to wait for
* completion of that transaction.
*/
if (ptid)
*ptid = journal->j_committing_transaction->t_tid;
ret = 1;
}
write_unlock(&journal->j_state_lock);
return ret;
}
/*
* Return 1 if a given transaction has not yet sent barrier request
* connected with a transaction commit. If 0 is returned, transaction
* may or may not have sent the barrier. Used to avoid sending barrier
* twice in common cases.
*/
int jbd2_trans_will_send_data_barrier(journal_t *journal, tid_t tid)
{
int ret = 0;
transaction_t *commit_trans;
if (!(journal->j_flags & JBD2_BARRIER))
return 0;
read_lock(&journal->j_state_lock);
/* Transaction already committed? */
if (tid_geq(journal->j_commit_sequence, tid))
goto out;
commit_trans = journal->j_committing_transaction;
if (!commit_trans || commit_trans->t_tid != tid) {
ret = 1;
goto out;
}
/*
* Transaction is being committed and we already proceeded to
* submitting a flush to fs partition?
*/
if (journal->j_fs_dev != journal->j_dev) {
if (!commit_trans->t_need_data_flush ||
commit_trans->t_state >= T_COMMIT_DFLUSH)
goto out;
} else {
if (commit_trans->t_state >= T_COMMIT_JFLUSH)
goto out;
}
ret = 1;
out:
read_unlock(&journal->j_state_lock);
return ret;
}
EXPORT_SYMBOL(jbd2_trans_will_send_data_barrier);
/*
* Wait for a specified commit to complete.
* The caller may not hold the journal lock.
*/
int jbd2_log_wait_commit(journal_t *journal, tid_t tid)
{
int err = 0;
read_lock(&journal->j_state_lock);
#ifdef CONFIG_JBD2_DEBUG
if (!tid_geq(journal->j_commit_request, tid)) {
printk(KERN_EMERG
"%s: error: j_commit_request=%d, tid=%d\n",
__func__, journal->j_commit_request, tid);
}
#endif
while (tid_gt(tid, journal->j_commit_sequence)) {
jbd_debug(1, "JBD2: want %d, j_commit_sequence=%d\n",
tid, journal->j_commit_sequence);
wake_up(&journal->j_wait_commit);
read_unlock(&journal->j_state_lock);
wait_event(journal->j_wait_done_commit,
!tid_gt(tid, journal->j_commit_sequence));
read_lock(&journal->j_state_lock);
}
read_unlock(&journal->j_state_lock);
if (unlikely(is_journal_aborted(journal))) {
printk(KERN_EMERG "journal commit I/O error\n");
err = -EIO;
}
return err;
}
/*
* When this function returns the transaction corresponding to tid
* will be completed. If the transaction has currently running, start
* committing that transaction before waiting for it to complete. If
* the transaction id is stale, it is by definition already completed,
* so just return SUCCESS.
*/
int jbd2_complete_transaction(journal_t *journal, tid_t tid)
{
int need_to_wait = 1;
read_lock(&journal->j_state_lock);
if (journal->j_running_transaction &&
journal->j_running_transaction->t_tid == tid) {
if (journal->j_commit_request != tid) {
/* transaction not yet started, so request it */
read_unlock(&journal->j_state_lock);
jbd2_log_start_commit(journal, tid);
goto wait_commit;
}
} else if (!(journal->j_committing_transaction &&
journal->j_committing_transaction->t_tid == tid))
need_to_wait = 0;
read_unlock(&journal->j_state_lock);
if (!need_to_wait)
return 0;
wait_commit:
return jbd2_log_wait_commit(journal, tid);
}
EXPORT_SYMBOL(jbd2_complete_transaction);
/*
* Log buffer allocation routines:
*/
int jbd2_journal_next_log_block(journal_t *journal, unsigned long long *retp)
{
unsigned long blocknr;
write_lock(&journal->j_state_lock);
J_ASSERT(journal->j_free > 1);
blocknr = journal->j_head;
journal->j_head++;
journal->j_free--;
if (journal->j_head == journal->j_last)
journal->j_head = journal->j_first;
write_unlock(&journal->j_state_lock);
return jbd2_journal_bmap(journal, blocknr, retp);
}
/*
* Conversion of logical to physical block numbers for the journal
*
* On external journals the journal blocks are identity-mapped, so
* this is a no-op. If needed, we can use j_blk_offset - everything is
* ready.
*/
int jbd2_journal_bmap(journal_t *journal, unsigned long blocknr,
unsigned long long *retp)
{
int err = 0;
unsigned long long ret;
if (journal->j_inode) {
ret = bmap(journal->j_inode, blocknr);
if (ret)
*retp = ret;
else {
printk(KERN_ALERT "%s: journal block not found "
"at offset %lu on %s\n",
__func__, blocknr, journal->j_devname);
err = -EIO;
__journal_abort_soft(journal, err);
}
} else {
*retp = blocknr; /* +journal->j_blk_offset */
}
return err;
}
/*
* We play buffer_head aliasing tricks to write data/metadata blocks to
* the journal without copying their contents, but for journal
* descriptor blocks we do need to generate bona fide buffers.
*
* After the caller of jbd2_journal_get_descriptor_buffer() has finished modifying
* the buffer's contents they really should run flush_dcache_page(bh->b_page).
* But we don't bother doing that, so there will be coherency problems with
* mmaps of blockdevs which hold live JBD-controlled filesystems.
*/
struct buffer_head *jbd2_journal_get_descriptor_buffer(journal_t *journal)
{
struct buffer_head *bh;
unsigned long long blocknr;
int err;
err = jbd2_journal_next_log_block(journal, &blocknr);
if (err)
return NULL;
bh = __getblk(journal->j_dev, blocknr, journal->j_blocksize);
if (!bh)
return NULL;
lock_buffer(bh);
memset(bh->b_data, 0, journal->j_blocksize);
set_buffer_uptodate(bh);
unlock_buffer(bh);
BUFFER_TRACE(bh, "return this buffer");
return bh;
}
/*
* Return tid of the oldest transaction in the journal and block in the journal
* where the transaction starts.
*
* If the journal is now empty, return which will be the next transaction ID
* we will write and where will that transaction start.
*
* The return value is 0 if journal tail cannot be pushed any further, 1 if
* it can.
*/
int jbd2_journal_get_log_tail(journal_t *journal, tid_t *tid,
unsigned long *block)
{
transaction_t *transaction;
int ret;
read_lock(&journal->j_state_lock);
spin_lock(&journal->j_list_lock);
transaction = journal->j_checkpoint_transactions;
if (transaction) {
*tid = transaction->t_tid;
*block = transaction->t_log_start;
} else if ((transaction = journal->j_committing_transaction) != NULL) {
*tid = transaction->t_tid;
*block = transaction->t_log_start;
} else if ((transaction = journal->j_running_transaction) != NULL) {
*tid = transaction->t_tid;
*block = journal->j_head;
} else {
*tid = journal->j_transaction_sequence;
*block = journal->j_head;
}
ret = tid_gt(*tid, journal->j_tail_sequence);
spin_unlock(&journal->j_list_lock);
read_unlock(&journal->j_state_lock);
return ret;
}
/*
* Update information in journal structure and in on disk journal superblock
* about log tail. This function does not check whether information passed in
* really pushes log tail further. It's responsibility of the caller to make
* sure provided log tail information is valid (e.g. by holding
* j_checkpoint_mutex all the time between computing log tail and calling this
* function as is the case with jbd2_cleanup_journal_tail()).
*
* Requires j_checkpoint_mutex
*/
void __jbd2_update_log_tail(journal_t *journal, tid_t tid, unsigned long block)
{
unsigned long freed;
BUG_ON(!mutex_is_locked(&journal->j_checkpoint_mutex));
/*
* We cannot afford for write to remain in drive's caches since as
* soon as we update j_tail, next transaction can start reusing journal
* space and if we lose sb update during power failure we'd replay
* old transaction with possibly newly overwritten data.
*/
jbd2_journal_update_sb_log_tail(journal, tid, block, WRITE_FUA);
write_lock(&journal->j_state_lock);
freed = block - journal->j_tail;
if (block < journal->j_tail)
freed += journal->j_last - journal->j_first;
trace_jbd2_update_log_tail(journal, tid, block, freed);
jbd_debug(1,
"Cleaning journal tail from %d to %d (offset %lu), "
"freeing %lu\n",
journal->j_tail_sequence, tid, block, freed);
journal->j_free += freed;
journal->j_tail_sequence = tid;
journal->j_tail = block;
write_unlock(&journal->j_state_lock);
}
/*
* This is a variaon of __jbd2_update_log_tail which checks for validity of
* provided log tail and locks j_checkpoint_mutex. So it is safe against races
* with other threads updating log tail.
*/
void jbd2_update_log_tail(journal_t *journal, tid_t tid, unsigned long block)
{
mutex_lock(&journal->j_checkpoint_mutex);
if (tid_gt(tid, journal->j_tail_sequence))
__jbd2_update_log_tail(journal, tid, block);
mutex_unlock(&journal->j_checkpoint_mutex);
}
struct jbd2_stats_proc_session {
journal_t *journal;
struct transaction_stats_s *stats;
int start;
int max;
};
static void *jbd2_seq_info_start(struct seq_file *seq, loff_t *pos)
{
return *pos ? NULL : SEQ_START_TOKEN;
}
static void *jbd2_seq_info_next(struct seq_file *seq, void *v, loff_t *pos)
{
return NULL;
}
static int jbd2_seq_info_show(struct seq_file *seq, void *v)
{
struct jbd2_stats_proc_session *s = seq->private;
if (v != SEQ_START_TOKEN)
return 0;
seq_printf(seq, "%lu transactions (%lu requested), "
"each up to %u blocks\n",
s->stats->ts_tid, s->stats->ts_requested,
s->journal->j_max_transaction_buffers);
if (s->stats->ts_tid == 0)
return 0;
seq_printf(seq, "average: \n %ums waiting for transaction\n",
jiffies_to_msecs(s->stats->run.rs_wait / s->stats->ts_tid));
seq_printf(seq, " %ums request delay\n",
(s->stats->ts_requested == 0) ? 0 :
jiffies_to_msecs(s->stats->run.rs_request_delay /
s->stats->ts_requested));
seq_printf(seq, " %ums running transaction\n",
jiffies_to_msecs(s->stats->run.rs_running / s->stats->ts_tid));
seq_printf(seq, " %ums transaction was being locked\n",
jiffies_to_msecs(s->stats->run.rs_locked / s->stats->ts_tid));
seq_printf(seq, " %ums flushing data (in ordered mode)\n",
jiffies_to_msecs(s->stats->run.rs_flushing / s->stats->ts_tid));
seq_printf(seq, " %ums logging transaction\n",
jiffies_to_msecs(s->stats->run.rs_logging / s->stats->ts_tid));
seq_printf(seq, " %lluus average transaction commit time\n",
div_u64(s->journal->j_average_commit_time, 1000));
seq_printf(seq, " %lu handles per transaction\n",
s->stats->run.rs_handle_count / s->stats->ts_tid);
seq_printf(seq, " %lu blocks per transaction\n",
s->stats->run.rs_blocks / s->stats->ts_tid);
seq_printf(seq, " %lu logged blocks per transaction\n",
s->stats->run.rs_blocks_logged / s->stats->ts_tid);
return 0;
}
static void jbd2_seq_info_stop(struct seq_file *seq, void *v)
{
}
static const struct seq_operations jbd2_seq_info_ops = {
.start = jbd2_seq_info_start,
.next = jbd2_seq_info_next,
.stop = jbd2_seq_info_stop,
.show = jbd2_seq_info_show,
};
static int jbd2_seq_info_open(struct inode *inode, struct file *file)
{
journal_t *journal = PDE_DATA(inode);
struct jbd2_stats_proc_session *s;
int rc, size;
s = kmalloc(sizeof(*s), GFP_KERNEL);
if (s == NULL)
return -ENOMEM;
size = sizeof(struct transaction_stats_s);
s->stats = kmalloc(size, GFP_KERNEL);
if (s->stats == NULL) {
kfree(s);
return -ENOMEM;
}
spin_lock(&journal->j_history_lock);
memcpy(s->stats, &journal->j_stats, size);
s->journal = journal;
spin_unlock(&journal->j_history_lock);
rc = seq_open(file, &jbd2_seq_info_ops);
if (rc == 0) {
struct seq_file *m = file->private_data;
m->private = s;
} else {
kfree(s->stats);
kfree(s);
}
return rc;
}
static int jbd2_seq_info_release(struct inode *inode, struct file *file)
{
struct seq_file *seq = file->private_data;
struct jbd2_stats_proc_session *s = seq->private;
kfree(s->stats);
kfree(s);
return seq_release(inode, file);
}
static const struct file_operations jbd2_seq_info_fops = {
.owner = THIS_MODULE,
.open = jbd2_seq_info_open,
.read = seq_read,
.llseek = seq_lseek,
.release = jbd2_seq_info_release,
};
static struct proc_dir_entry *proc_jbd2_stats;
static void jbd2_stats_proc_init(journal_t *journal)
{
journal->j_proc_entry = proc_mkdir(journal->j_devname, proc_jbd2_stats);
if (journal->j_proc_entry) {
proc_create_data("info", S_IRUGO, journal->j_proc_entry,
&jbd2_seq_info_fops, journal);
}
}
static void jbd2_stats_proc_exit(journal_t *journal)
{
remove_proc_entry("info", journal->j_proc_entry);
remove_proc_entry(journal->j_devname, proc_jbd2_stats);
}
/*
* Management for journal control blocks: functions to create and
* destroy journal_t structures, and to initialise and read existing
* journal blocks from disk. */
/* First: create and setup a journal_t object in memory. We initialise
* very few fields yet: that has to wait until we have created the
* journal structures from from scratch, or loaded them from disk. */
static journal_t * journal_init_common (void)
{
journal_t *journal;
int err;
journal = kzalloc(sizeof(*journal), GFP_KERNEL);
if (!journal)
return NULL;
init_waitqueue_head(&journal->j_wait_transaction_locked);
init_waitqueue_head(&journal->j_wait_done_commit);
init_waitqueue_head(&journal->j_wait_commit);
init_waitqueue_head(&journal->j_wait_updates);
init_waitqueue_head(&journal->j_wait_reserved);
mutex_init(&journal->j_barrier);
mutex_init(&journal->j_checkpoint_mutex);
spin_lock_init(&journal->j_revoke_lock);
spin_lock_init(&journal->j_list_lock);
rwlock_init(&journal->j_state_lock);
journal->j_commit_interval = (HZ * JBD2_DEFAULT_MAX_COMMIT_AGE);
journal->j_min_batch_time = 0;
journal->j_max_batch_time = 15000; /* 15ms */
atomic_set(&journal->j_reserved_credits, 0);
/* The journal is marked for error until we succeed with recovery! */
journal->j_flags = JBD2_ABORT;
/* Set up a default-sized revoke table for the new mount. */
err = jbd2_journal_init_revoke(journal, JOURNAL_REVOKE_DEFAULT_HASH);
if (err) {
kfree(journal);
return NULL;
}
spin_lock_init(&journal->j_history_lock);
return journal;
}
/* jbd2_journal_init_dev and jbd2_journal_init_inode:
*
* Create a journal structure assigned some fixed set of disk blocks to
* the journal. We don't actually touch those disk blocks yet, but we
* need to set up all of the mapping information to tell the journaling
* system where the journal blocks are.
*
*/
/**
* journal_t * jbd2_journal_init_dev() - creates and initialises a journal structure
* @bdev: Block device on which to create the journal
* @fs_dev: Device which hold journalled filesystem for this journal.
* @start: Block nr Start of journal.
* @len: Length of the journal in blocks.
* @blocksize: blocksize of journalling device
*
* Returns: a newly created journal_t *
*
* jbd2_journal_init_dev creates a journal which maps a fixed contiguous
* range of blocks on an arbitrary block device.
*
*/
journal_t * jbd2_journal_init_dev(struct block_device *bdev,
struct block_device *fs_dev,
unsigned long long start, int len, int blocksize)
{
journal_t *journal = journal_init_common();
struct buffer_head *bh;
char *p;
int n;
if (!journal)
return NULL;
/* journal descriptor can store up to n blocks -bzzz */
journal->j_blocksize = blocksize;
journal->j_dev = bdev;
journal->j_fs_dev = fs_dev;
journal->j_blk_offset = start;
journal->j_maxlen = len;
bdevname(journal->j_dev, journal->j_devname);
p = journal->j_devname;
while ((p = strchr(p, '/')))
*p = '!';
jbd2_stats_proc_init(journal);
n = journal->j_blocksize / sizeof(journal_block_tag_t);
journal->j_wbufsize = n;
journal->j_wbuf = kmalloc(n * sizeof(struct buffer_head*), GFP_KERNEL);
if (!journal->j_wbuf) {
printk(KERN_ERR "%s: Can't allocate bhs for commit thread\n",
__func__);
goto out_err;
}
bh = __getblk(journal->j_dev, start, journal->j_blocksize);
if (!bh) {
printk(KERN_ERR
"%s: Cannot get buffer for journal superblock\n",
__func__);
goto out_err;
}
journal->j_sb_buffer = bh;
journal->j_superblock = (journal_superblock_t *)bh->b_data;
return journal;
out_err:
kfree(journal->j_wbuf);
jbd2_stats_proc_exit(journal);
kfree(journal);
return NULL;
}
/**
* journal_t * jbd2_journal_init_inode () - creates a journal which maps to a inode.
* @inode: An inode to create the journal in
*
* jbd2_journal_init_inode creates a journal which maps an on-disk inode as
* the journal. The inode must exist already, must support bmap() and
* must have all data blocks preallocated.
*/
journal_t * jbd2_journal_init_inode (struct inode *inode)
{
struct buffer_head *bh;
journal_t *journal = journal_init_common();
char *p;
int err;
int n;
unsigned long long blocknr;
if (!journal)
return NULL;
journal->j_dev = journal->j_fs_dev = inode->i_sb->s_bdev;
journal->j_inode = inode;
bdevname(journal->j_dev, journal->j_devname);
p = journal->j_devname;
while ((p = strchr(p, '/')))
*p = '!';
p = journal->j_devname + strlen(journal->j_devname);
sprintf(p, "-%lu", journal->j_inode->i_ino);
jbd_debug(1,
"journal %p: inode %s/%ld, size %Ld, bits %d, blksize %ld\n",
journal, inode->i_sb->s_id, inode->i_ino,
(long long) inode->i_size,
inode->i_sb->s_blocksize_bits, inode->i_sb->s_blocksize);
journal->j_maxlen = inode->i_size >> inode->i_sb->s_blocksize_bits;
journal->j_blocksize = inode->i_sb->s_blocksize;
jbd2_stats_proc_init(journal);
/* journal descriptor can store up to n blocks -bzzz */
n = journal->j_blocksize / sizeof(journal_block_tag_t);
journal->j_wbufsize = n;
journal->j_wbuf = kmalloc(n * sizeof(struct buffer_head*), GFP_KERNEL);
if (!journal->j_wbuf) {
printk(KERN_ERR "%s: Can't allocate bhs for commit thread\n",
__func__);
goto out_err;
}
err = jbd2_journal_bmap(journal, 0, &blocknr);
/* If that failed, give up */
if (err) {
printk(KERN_ERR "%s: Cannot locate journal superblock\n",
__func__);
goto out_err;
}
bh = __getblk(journal->j_dev, blocknr, journal->j_blocksize);
if (!bh) {
printk(KERN_ERR
"%s: Cannot get buffer for journal superblock\n",
__func__);
goto out_err;
}
journal->j_sb_buffer = bh;
journal->j_superblock = (journal_superblock_t *)bh->b_data;
return journal;
out_err:
kfree(journal->j_wbuf);
jbd2_stats_proc_exit(journal);
kfree(journal);
return NULL;
}
/*
* If the journal init or create aborts, we need to mark the journal
* superblock as being NULL to prevent the journal destroy from writing
* back a bogus superblock.
*/
static void journal_fail_superblock (journal_t *journal)
{
struct buffer_head *bh = journal->j_sb_buffer;
brelse(bh);
journal->j_sb_buffer = NULL;
}
/*
* Given a journal_t structure, initialise the various fields for
* startup of a new journaling session. We use this both when creating
* a journal, and after recovering an old journal to reset it for
* subsequent use.
*/
static int journal_reset(journal_t *journal)
{
journal_superblock_t *sb = journal->j_superblock;
unsigned long long first, last;
first = be32_to_cpu(sb->s_first);
last = be32_to_cpu(sb->s_maxlen);
if (first + JBD2_MIN_JOURNAL_BLOCKS > last + 1) {
printk(KERN_ERR "JBD2: Journal too short (blocks %llu-%llu).\n",
first, last);
journal_fail_superblock(journal);
return -EINVAL;
}
journal->j_first = first;
journal->j_last = last;
journal->j_head = first;
journal->j_tail = first;
journal->j_free = last - first;
journal->j_tail_sequence = journal->j_transaction_sequence;
journal->j_commit_sequence = journal->j_transaction_sequence - 1;
journal->j_commit_request = journal->j_commit_sequence;
journal->j_max_transaction_buffers = journal->j_maxlen / 4;
/*
* As a special case, if the on-disk copy is already marked as needing
* no recovery (s_start == 0), then we can safely defer the superblock
* update until the next commit by setting JBD2_FLUSHED. This avoids
* attempting a write to a potential-readonly device.
*/
if (sb->s_start == 0) {
jbd_debug(1, "JBD2: Skipping superblock update on recovered sb "
"(start %ld, seq %d, errno %d)\n",
journal->j_tail, journal->j_tail_sequence,
journal->j_errno);
journal->j_flags |= JBD2_FLUSHED;
} else {
/* Lock here to make assertions happy... */
mutex_lock(&journal->j_checkpoint_mutex);
/*
* Update log tail information. We use WRITE_FUA since new
* transaction will start reusing journal space and so we
* must make sure information about current log tail is on
* disk before that.
*/
jbd2_journal_update_sb_log_tail(journal,
journal->j_tail_sequence,
journal->j_tail,
WRITE_FUA);
mutex_unlock(&journal->j_checkpoint_mutex);
}
return jbd2_journal_start_thread(journal);
}
static void jbd2_write_superblock(journal_t *journal, int write_op)
{
struct buffer_head *bh = journal->j_sb_buffer;
journal_superblock_t *sb = journal->j_superblock;
int ret;
trace_jbd2_write_superblock(journal, write_op);
if (!(journal->j_flags & JBD2_BARRIER))
write_op &= ~(REQ_FUA | REQ_FLUSH);
lock_buffer(bh);
if (buffer_write_io_error(bh)) {
/*
* Oh, dear. A previous attempt to write the journal
* superblock failed. This could happen because the
* USB device was yanked out. Or it could happen to
* be a transient write error and maybe the block will
* be remapped. Nothing we can do but to retry the
* write and hope for the best.
*/
printk(KERN_ERR "JBD2: previous I/O error detected "
"for journal superblock update for %s.\n",
journal->j_devname);
clear_buffer_write_io_error(bh);
set_buffer_uptodate(bh);
}
jbd2_superblock_csum_set(journal, sb);
get_bh(bh);
bh->b_end_io = end_buffer_write_sync;
ret = submit_bh(write_op, bh);
wait_on_buffer(bh);
if (buffer_write_io_error(bh)) {
clear_buffer_write_io_error(bh);
set_buffer_uptodate(bh);
ret = -EIO;
}
if (ret) {
printk(KERN_ERR "JBD2: Error %d detected when updating "
"journal superblock for %s.\n", ret,
journal->j_devname);
}
}
/**
* jbd2_journal_update_sb_log_tail() - Update log tail in journal sb on disk.
* @journal: The journal to update.
* @tail_tid: TID of the new transaction at the tail of the log
* @tail_block: The first block of the transaction at the tail of the log
* @write_op: With which operation should we write the journal sb
*
* Update a journal's superblock information about log tail and write it to
* disk, waiting for the IO to complete.
*/
void jbd2_journal_update_sb_log_tail(journal_t *journal, tid_t tail_tid,
unsigned long tail_block, int write_op)
{
journal_superblock_t *sb = journal->j_superblock;
BUG_ON(!mutex_is_locked(&journal->j_checkpoint_mutex));
jbd_debug(1, "JBD2: updating superblock (start %lu, seq %u)\n",
tail_block, tail_tid);
sb->s_sequence = cpu_to_be32(tail_tid);
sb->s_start = cpu_to_be32(tail_block);
jbd2_write_superblock(journal, write_op);
/* Log is no longer empty */
write_lock(&journal->j_state_lock);
WARN_ON(!sb->s_sequence);
journal->j_flags &= ~JBD2_FLUSHED;
write_unlock(&journal->j_state_lock);
}
/**
* jbd2_mark_journal_empty() - Mark on disk journal as empty.
* @journal: The journal to update.
*
* Update a journal's dynamic superblock fields to show that journal is empty.
* Write updated superblock to disk waiting for IO to complete.
*/
static void jbd2_mark_journal_empty(journal_t *journal)
{
journal_superblock_t *sb = journal->j_superblock;
BUG_ON(!mutex_is_locked(&journal->j_checkpoint_mutex));
read_lock(&journal->j_state_lock);
/* Is it already empty? */
if (sb->s_start == 0) {
read_unlock(&journal->j_state_lock);
return;
}
jbd_debug(1, "JBD2: Marking journal as empty (seq %d)\n",
journal->j_tail_sequence);
sb->s_sequence = cpu_to_be32(journal->j_tail_sequence);
sb->s_start = cpu_to_be32(0);
read_unlock(&journal->j_state_lock);
jbd2_write_superblock(journal, WRITE_FUA);
/* Log is no longer empty */
write_lock(&journal->j_state_lock);
journal->j_flags |= JBD2_FLUSHED;
write_unlock(&journal->j_state_lock);
}
/**
* jbd2_journal_update_sb_errno() - Update error in the journal.
* @journal: The journal to update.
*
* Update a journal's errno. Write updated superblock to disk waiting for IO
* to complete.
*/
void jbd2_journal_update_sb_errno(journal_t *journal)
{
journal_superblock_t *sb = journal->j_superblock;
read_lock(&journal->j_state_lock);
jbd_debug(1, "JBD2: updating superblock error (errno %d)\n",
journal->j_errno);
sb->s_errno = cpu_to_be32(journal->j_errno);
read_unlock(&journal->j_state_lock);
jbd2_write_superblock(journal, WRITE_SYNC);
}
EXPORT_SYMBOL(jbd2_journal_update_sb_errno);
/*
* Read the superblock for a given journal, performing initial
* validation of the format.
*/
static int journal_get_superblock(journal_t *journal)
{
struct buffer_head *bh;
journal_superblock_t *sb;
int err = -EIO;
bh = journal->j_sb_buffer;
J_ASSERT(bh != NULL);
if (!buffer_uptodate(bh)) {
ll_rw_block(READ, 1, &bh);
wait_on_buffer(bh);
if (!buffer_uptodate(bh)) {
printk(KERN_ERR
"JBD2: IO error reading journal superblock\n");
goto out;
}
}
if (buffer_verified(bh))
return 0;
sb = journal->j_superblock;
err = -EINVAL;
if (sb->s_header.h_magic != cpu_to_be32(JBD2_MAGIC_NUMBER) ||
sb->s_blocksize != cpu_to_be32(journal->j_blocksize)) {
printk(KERN_WARNING "JBD2: no valid journal superblock found\n");
goto out;
}
switch(be32_to_cpu(sb->s_header.h_blocktype)) {
case JBD2_SUPERBLOCK_V1:
journal->j_format_version = 1;
break;
case JBD2_SUPERBLOCK_V2:
journal->j_format_version = 2;
break;
default:
printk(KERN_WARNING "JBD2: unrecognised superblock format ID\n");
goto out;
}
if (be32_to_cpu(sb->s_maxlen) < journal->j_maxlen)
journal->j_maxlen = be32_to_cpu(sb->s_maxlen);
else if (be32_to_cpu(sb->s_maxlen) > journal->j_maxlen) {
printk(KERN_WARNING "JBD2: journal file too short\n");
goto out;
}
if (be32_to_cpu(sb->s_first) == 0 ||
be32_to_cpu(sb->s_first) >= journal->j_maxlen) {
printk(KERN_WARNING
"JBD2: Invalid start block of journal: %u\n",
be32_to_cpu(sb->s_first));
goto out;
}
if (JBD2_HAS_COMPAT_FEATURE(journal, JBD2_FEATURE_COMPAT_CHECKSUM) &&
JBD2_HAS_INCOMPAT_FEATURE(journal, JBD2_FEATURE_INCOMPAT_CSUM_V2)) {
/* Can't have checksum v1 and v2 on at the same time! */
printk(KERN_ERR "JBD: Can't enable checksumming v1 and v2 "
"at the same time!\n");
goto out;
}
if (!jbd2_verify_csum_type(journal, sb)) {
printk(KERN_ERR "JBD: Unknown checksum type\n");
goto out;
}
/* Load the checksum driver */
if (JBD2_HAS_INCOMPAT_FEATURE(journal, JBD2_FEATURE_INCOMPAT_CSUM_V2)) {
journal->j_chksum_driver = crypto_alloc_shash("crc32c", 0, 0);
if (IS_ERR(journal->j_chksum_driver)) {
printk(KERN_ERR "JBD: Cannot load crc32c driver.\n");
err = PTR_ERR(journal->j_chksum_driver);
journal->j_chksum_driver = NULL;
goto out;
}
}
/* Check superblock checksum */
if (!jbd2_superblock_csum_verify(journal, sb)) {
printk(KERN_ERR "JBD: journal checksum error\n");
goto out;
}
/* Precompute checksum seed for all metadata */
if (JBD2_HAS_INCOMPAT_FEATURE(journal, JBD2_FEATURE_INCOMPAT_CSUM_V2))
journal->j_csum_seed = jbd2_chksum(journal, ~0, sb->s_uuid,
sizeof(sb->s_uuid));
set_buffer_verified(bh);
return 0;
out:
journal_fail_superblock(journal);
return err;
}
/*
* Load the on-disk journal superblock and read the key fields into the
* journal_t.
*/
static int load_superblock(journal_t *journal)
{
int err;
journal_superblock_t *sb;
err = journal_get_superblock(journal);
if (err)
return err;
sb = journal->j_superblock;
journal->j_tail_sequence = be32_to_cpu(sb->s_sequence);
journal->j_tail = be32_to_cpu(sb->s_start);
journal->j_first = be32_to_cpu(sb->s_first);
journal->j_last = be32_to_cpu(sb->s_maxlen);
journal->j_errno = be32_to_cpu(sb->s_errno);
return 0;
}
/**
* int jbd2_journal_load() - Read journal from disk.
* @journal: Journal to act on.
*
* Given a journal_t structure which tells us which disk blocks contain
* a journal, read the journal from disk to initialise the in-memory
* structures.
*/
int jbd2_journal_load(journal_t *journal)
{
int err;
journal_superblock_t *sb;
err = load_superblock(journal);
if (err)
return err;
sb = journal->j_superblock;
/* If this is a V2 superblock, then we have to check the
* features flags on it. */
if (journal->j_format_version >= 2) {
if ((sb->s_feature_ro_compat &
~cpu_to_be32(JBD2_KNOWN_ROCOMPAT_FEATURES)) ||
(sb->s_feature_incompat &
~cpu_to_be32(JBD2_KNOWN_INCOMPAT_FEATURES))) {
printk(KERN_WARNING
"JBD2: Unrecognised features on journal\n");
return -EINVAL;
}
}
/*
* Create a slab for this blocksize
*/
err = jbd2_journal_create_slab(be32_to_cpu(sb->s_blocksize));
if (err)
return err;
/* Let the recovery code check whether it needs to recover any
* data from the journal. */
if (jbd2_journal_recover(journal))
goto recovery_error;
if (journal->j_failed_commit) {
printk(KERN_ERR "JBD2: journal transaction %u on %s "
"is corrupt.\n", journal->j_failed_commit,
journal->j_devname);
return -EIO;
}
/* OK, we've finished with the dynamic journal bits:
* reinitialise the dynamic contents of the superblock in memory
* and reset them on disk. */
if (journal_reset(journal))
goto recovery_error;
journal->j_flags &= ~JBD2_ABORT;
journal->j_flags |= JBD2_LOADED;
return 0;
recovery_error:
printk(KERN_WARNING "JBD2: recovery failed\n");
return -EIO;
}
/**
* void jbd2_journal_destroy() - Release a journal_t structure.
* @journal: Journal to act on.
*
* Release a journal_t structure once it is no longer in use by the
* journaled object.
* Return <0 if we couldn't clean up the journal.
*/
int jbd2_journal_destroy(journal_t *journal)
{
int err = 0;
/* Wait for the commit thread to wake up and die. */
journal_kill_thread(journal);
/* Force a final log commit */
if (journal->j_running_transaction)
jbd2_journal_commit_transaction(journal);
/* Force any old transactions to disk */
/* Totally anal locking here... */
spin_lock(&journal->j_list_lock);
while (journal->j_checkpoint_transactions != NULL) {
spin_unlock(&journal->j_list_lock);
mutex_lock(&journal->j_checkpoint_mutex);
jbd2_log_do_checkpoint(journal);
mutex_unlock(&journal->j_checkpoint_mutex);
spin_lock(&journal->j_list_lock);
}
J_ASSERT(journal->j_running_transaction == NULL);
J_ASSERT(journal->j_committing_transaction == NULL);
J_ASSERT(journal->j_checkpoint_transactions == NULL);
spin_unlock(&journal->j_list_lock);
if (journal->j_sb_buffer) {
if (!is_journal_aborted(journal)) {
mutex_lock(&journal->j_checkpoint_mutex);
jbd2_mark_journal_empty(journal);
mutex_unlock(&journal->j_checkpoint_mutex);
} else
err = -EIO;
brelse(journal->j_sb_buffer);
}
if (journal->j_proc_entry)
jbd2_stats_proc_exit(journal);
if (journal->j_inode)
iput(journal->j_inode);
if (journal->j_revoke)
jbd2_journal_destroy_revoke(journal);
if (journal->j_chksum_driver)
crypto_free_shash(journal->j_chksum_driver);
kfree(journal->j_wbuf);
kfree(journal);
return err;
}
/**
*int jbd2_journal_check_used_features () - Check if features specified are used.
* @journal: Journal to check.
* @compat: bitmask of compatible features
* @ro: bitmask of features that force read-only mount
* @incompat: bitmask of incompatible features
*
* Check whether the journal uses all of a given set of
* features. Return true (non-zero) if it does.
**/
int jbd2_journal_check_used_features (journal_t *journal, unsigned long compat,
unsigned long ro, unsigned long incompat)
{
journal_superblock_t *sb;
if (!compat && !ro && !incompat)
return 1;
/* Load journal superblock if it is not loaded yet. */
if (journal->j_format_version == 0 &&
journal_get_superblock(journal) != 0)
return 0;
if (journal->j_format_version == 1)
return 0;
sb = journal->j_superblock;
if (((be32_to_cpu(sb->s_feature_compat) & compat) == compat) &&
((be32_to_cpu(sb->s_feature_ro_compat) & ro) == ro) &&
((be32_to_cpu(sb->s_feature_incompat) & incompat) == incompat))
return 1;
return 0;
}
/**
* int jbd2_journal_check_available_features() - Check feature set in journalling layer
* @journal: Journal to check.
* @compat: bitmask of compatible features
* @ro: bitmask of features that force read-only mount
* @incompat: bitmask of incompatible features
*
* Check whether the journaling code supports the use of
* all of a given set of features on this journal. Return true
* (non-zero) if it can. */
int jbd2_journal_check_available_features (journal_t *journal, unsigned long compat,
unsigned long ro, unsigned long incompat)
{
if (!compat && !ro && !incompat)
return 1;
/* We can support any known requested features iff the
* superblock is in version 2. Otherwise we fail to support any
* extended sb features. */
if (journal->j_format_version != 2)
return 0;
if ((compat & JBD2_KNOWN_COMPAT_FEATURES) == compat &&
(ro & JBD2_KNOWN_ROCOMPAT_FEATURES) == ro &&
(incompat & JBD2_KNOWN_INCOMPAT_FEATURES) == incompat)
return 1;
return 0;
}
/**
* int jbd2_journal_set_features () - Mark a given journal feature in the superblock
* @journal: Journal to act on.
* @compat: bitmask of compatible features
* @ro: bitmask of features that force read-only mount
* @incompat: bitmask of incompatible features
*
* Mark a given journal feature as present on the
* superblock. Returns true if the requested features could be set.
*
*/
int jbd2_journal_set_features (journal_t *journal, unsigned long compat,
unsigned long ro, unsigned long incompat)
{
#define INCOMPAT_FEATURE_ON(f) \
((incompat & (f)) && !(sb->s_feature_incompat & cpu_to_be32(f)))
#define COMPAT_FEATURE_ON(f) \
((compat & (f)) && !(sb->s_feature_compat & cpu_to_be32(f)))
journal_superblock_t *sb;
if (jbd2_journal_check_used_features(journal, compat, ro, incompat))
return 1;
if (!jbd2_journal_check_available_features(journal, compat, ro, incompat))
return 0;
/* Asking for checksumming v2 and v1? Only give them v2. */
if (incompat & JBD2_FEATURE_INCOMPAT_CSUM_V2 &&
compat & JBD2_FEATURE_COMPAT_CHECKSUM)
compat &= ~JBD2_FEATURE_COMPAT_CHECKSUM;
jbd_debug(1, "Setting new features 0x%lx/0x%lx/0x%lx\n",
compat, ro, incompat);
sb = journal->j_superblock;
/* If enabling v2 checksums, update superblock */
if (INCOMPAT_FEATURE_ON(JBD2_FEATURE_INCOMPAT_CSUM_V2)) {
sb->s_checksum_type = JBD2_CRC32C_CHKSUM;
sb->s_feature_compat &=
~cpu_to_be32(JBD2_FEATURE_COMPAT_CHECKSUM);
/* Load the checksum driver */
if (journal->j_chksum_driver == NULL) {
journal->j_chksum_driver = crypto_alloc_shash("crc32c",
0, 0);
if (IS_ERR(journal->j_chksum_driver)) {
printk(KERN_ERR "JBD: Cannot load crc32c "
"driver.\n");
journal->j_chksum_driver = NULL;
return 0;
}
}
/* Precompute checksum seed for all metadata */
if (JBD2_HAS_INCOMPAT_FEATURE(journal,
JBD2_FEATURE_INCOMPAT_CSUM_V2))
journal->j_csum_seed = jbd2_chksum(journal, ~0,
sb->s_uuid,
sizeof(sb->s_uuid));
}
/* If enabling v1 checksums, downgrade superblock */
if (COMPAT_FEATURE_ON(JBD2_FEATURE_COMPAT_CHECKSUM))
sb->s_feature_incompat &=
~cpu_to_be32(JBD2_FEATURE_INCOMPAT_CSUM_V2);
sb->s_feature_compat |= cpu_to_be32(compat);
sb->s_feature_ro_compat |= cpu_to_be32(ro);
sb->s_feature_incompat |= cpu_to_be32(incompat);
return 1;
#undef COMPAT_FEATURE_ON
#undef INCOMPAT_FEATURE_ON
}
/*
* jbd2_journal_clear_features () - Clear a given journal feature in the
* superblock
* @journal: Journal to act on.
* @compat: bitmask of compatible features
* @ro: bitmask of features that force read-only mount
* @incompat: bitmask of incompatible features
*
* Clear a given journal feature as present on the
* superblock.
*/
void jbd2_journal_clear_features(journal_t *journal, unsigned long compat,
unsigned long ro, unsigned long incompat)
{
journal_superblock_t *sb;
jbd_debug(1, "Clear features 0x%lx/0x%lx/0x%lx\n",
compat, ro, incompat);
sb = journal->j_superblock;
sb->s_feature_compat &= ~cpu_to_be32(compat);
sb->s_feature_ro_compat &= ~cpu_to_be32(ro);
sb->s_feature_incompat &= ~cpu_to_be32(incompat);
}
EXPORT_SYMBOL(jbd2_journal_clear_features);
/**
* int jbd2_journal_flush () - Flush journal
* @journal: Journal to act on.
*
* Flush all data for a given journal to disk and empty the journal.
* Filesystems can use this when remounting readonly to ensure that
* recovery does not need to happen on remount.
*/
int jbd2_journal_flush(journal_t *journal)
{
int err = 0;
transaction_t *transaction = NULL;
write_lock(&journal->j_state_lock);
/* Force everything buffered to the log... */
if (journal->j_running_transaction) {
transaction = journal->j_running_transaction;
__jbd2_log_start_commit(journal, transaction->t_tid);
} else if (journal->j_committing_transaction)
transaction = journal->j_committing_transaction;
/* Wait for the log commit to complete... */
if (transaction) {
tid_t tid = transaction->t_tid;
write_unlock(&journal->j_state_lock);
jbd2_log_wait_commit(journal, tid);
} else {
write_unlock(&journal->j_state_lock);
}
/* ...and flush everything in the log out to disk. */
spin_lock(&journal->j_list_lock);
while (!err && journal->j_checkpoint_transactions != NULL) {
spin_unlock(&journal->j_list_lock);
mutex_lock(&journal->j_checkpoint_mutex);
err = jbd2_log_do_checkpoint(journal);
mutex_unlock(&journal->j_checkpoint_mutex);
spin_lock(&journal->j_list_lock);
}
spin_unlock(&journal->j_list_lock);
if (is_journal_aborted(journal))
return -EIO;
mutex_lock(&journal->j_checkpoint_mutex);
jbd2_cleanup_journal_tail(journal);
/* Finally, mark the journal as really needing no recovery.
* This sets s_start==0 in the underlying superblock, which is
* the magic code for a fully-recovered superblock. Any future
* commits of data to the journal will restore the current
* s_start value. */
jbd2_mark_journal_empty(journal);
mutex_unlock(&journal->j_checkpoint_mutex);
write_lock(&journal->j_state_lock);
J_ASSERT(!journal->j_running_transaction);
J_ASSERT(!journal->j_committing_transaction);
J_ASSERT(!journal->j_checkpoint_transactions);
J_ASSERT(journal->j_head == journal->j_tail);
J_ASSERT(journal->j_tail_sequence == journal->j_transaction_sequence);
write_unlock(&journal->j_state_lock);
return 0;
}
/**
* int jbd2_journal_wipe() - Wipe journal contents
* @journal: Journal to act on.
* @write: flag (see below)
*
* Wipe out all of the contents of a journal, safely. This will produce
* a warning if the journal contains any valid recovery information.
* Must be called between journal_init_*() and jbd2_journal_load().
*
* If 'write' is non-zero, then we wipe out the journal on disk; otherwise
* we merely suppress recovery.
*/
int jbd2_journal_wipe(journal_t *journal, int write)
{
int err = 0;
J_ASSERT (!(journal->j_flags & JBD2_LOADED));
err = load_superblock(journal);
if (err)
return err;
if (!journal->j_tail)
goto no_recovery;
printk(KERN_WARNING "JBD2: %s recovery information on journal\n",
write ? "Clearing" : "Ignoring");
err = jbd2_journal_skip_recovery(journal);
if (write) {
/* Lock to make assertions happy... */
mutex_lock(&journal->j_checkpoint_mutex);
jbd2_mark_journal_empty(journal);
mutex_unlock(&journal->j_checkpoint_mutex);
}
no_recovery:
return err;
}
/*
* Journal abort has very specific semantics, which we describe
* for journal abort.
*
* Two internal functions, which provide abort to the jbd layer
* itself are here.
*/
/*
* Quick version for internal journal use (doesn't lock the journal).
* Aborts hard --- we mark the abort as occurred, but do _nothing_ else,
* and don't attempt to make any other journal updates.
*/
void __jbd2_journal_abort_hard(journal_t *journal)
{
transaction_t *transaction;
if (journal->j_flags & JBD2_ABORT)
return;
printk(KERN_ERR "Aborting journal on device %s.\n",
journal->j_devname);
write_lock(&journal->j_state_lock);
journal->j_flags |= JBD2_ABORT;
transaction = journal->j_running_transaction;
if (transaction)
__jbd2_log_start_commit(journal, transaction->t_tid);
write_unlock(&journal->j_state_lock);
}
/* Soft abort: record the abort error status in the journal superblock,
* but don't do any other IO. */
static void __journal_abort_soft (journal_t *journal, int errno)
{
if (journal->j_flags & JBD2_ABORT)
return;
if (!journal->j_errno)
journal->j_errno = errno;
__jbd2_journal_abort_hard(journal);
if (errno)
jbd2_journal_update_sb_errno(journal);
}
/**
* void jbd2_journal_abort () - Shutdown the journal immediately.
* @journal: the journal to shutdown.
* @errno: an error number to record in the journal indicating
* the reason for the shutdown.
*
* Perform a complete, immediate shutdown of the ENTIRE
* journal (not of a single transaction). This operation cannot be
* undone without closing and reopening the journal.
*
* The jbd2_journal_abort function is intended to support higher level error
* recovery mechanisms such as the ext2/ext3 remount-readonly error
* mode.
*
* Journal abort has very specific semantics. Any existing dirty,
* unjournaled buffers in the main filesystem will still be written to
* disk by bdflush, but the journaling mechanism will be suspended
* immediately and no further transaction commits will be honoured.
*
* Any dirty, journaled buffers will be written back to disk without
* hitting the journal. Atomicity cannot be guaranteed on an aborted
* filesystem, but we _do_ attempt to leave as much data as possible
* behind for fsck to use for cleanup.
*
* Any attempt to get a new transaction handle on a journal which is in
* ABORT state will just result in an -EROFS error return. A
* jbd2_journal_stop on an existing handle will return -EIO if we have
* entered abort state during the update.
*
* Recursive transactions are not disturbed by journal abort until the
* final jbd2_journal_stop, which will receive the -EIO error.
*
* Finally, the jbd2_journal_abort call allows the caller to supply an errno
* which will be recorded (if possible) in the journal superblock. This
* allows a client to record failure conditions in the middle of a
* transaction without having to complete the transaction to record the
* failure to disk. ext3_error, for example, now uses this
* functionality.
*
* Errors which originate from within the journaling layer will NOT
* supply an errno; a null errno implies that absolutely no further
* writes are done to the journal (unless there are any already in
* progress).
*
*/
void jbd2_journal_abort(journal_t *journal, int errno)
{
__journal_abort_soft(journal, errno);
}
/**
* int jbd2_journal_errno () - returns the journal's error state.
* @journal: journal to examine.
*
* This is the errno number set with jbd2_journal_abort(), the last
* time the journal was mounted - if the journal was stopped
* without calling abort this will be 0.
*
* If the journal has been aborted on this mount time -EROFS will
* be returned.
*/
int jbd2_journal_errno(journal_t *journal)
{
int err;
read_lock(&journal->j_state_lock);
if (journal->j_flags & JBD2_ABORT)
err = -EROFS;
else
err = journal->j_errno;
read_unlock(&journal->j_state_lock);
return err;
}
/**
* int jbd2_journal_clear_err () - clears the journal's error state
* @journal: journal to act on.
*
* An error must be cleared or acked to take a FS out of readonly
* mode.
*/
int jbd2_journal_clear_err(journal_t *journal)
{
int err = 0;
write_lock(&journal->j_state_lock);
if (journal->j_flags & JBD2_ABORT)
err = -EROFS;
else
journal->j_errno = 0;
write_unlock(&journal->j_state_lock);
return err;
}
/**
* void jbd2_journal_ack_err() - Ack journal err.
* @journal: journal to act on.
*
* An error must be cleared or acked to take a FS out of readonly
* mode.
*/
void jbd2_journal_ack_err(journal_t *journal)
{
write_lock(&journal->j_state_lock);
if (journal->j_errno)
journal->j_flags |= JBD2_ACK_ERR;
write_unlock(&journal->j_state_lock);
}
int jbd2_journal_blocks_per_page(struct inode *inode)
{
return 1 << (PAGE_CACHE_SHIFT - inode->i_sb->s_blocksize_bits);
}
/*
* helper functions to deal with 32 or 64bit block numbers.
*/
size_t journal_tag_bytes(journal_t *journal)
{
journal_block_tag_t tag;
size_t x = 0;
if (JBD2_HAS_INCOMPAT_FEATURE(journal, JBD2_FEATURE_INCOMPAT_CSUM_V2))
x += sizeof(tag.t_checksum);
if (JBD2_HAS_INCOMPAT_FEATURE(journal, JBD2_FEATURE_INCOMPAT_64BIT))
return x + JBD2_TAG_SIZE64;
else
return x + JBD2_TAG_SIZE32;
}
/*
* JBD memory management
*
* These functions are used to allocate block-sized chunks of memory
* used for making copies of buffer_head data. Very often it will be
* page-sized chunks of data, but sometimes it will be in
* sub-page-size chunks. (For example, 16k pages on Power systems
* with a 4k block file system.) For blocks smaller than a page, we
* use a SLAB allocator. There are slab caches for each block size,
* which are allocated at mount time, if necessary, and we only free
* (all of) the slab caches when/if the jbd2 module is unloaded. For
* this reason we don't need to a mutex to protect access to
* jbd2_slab[] allocating or releasing memory; only in
* jbd2_journal_create_slab().
*/
#define JBD2_MAX_SLABS 8
static struct kmem_cache *jbd2_slab[JBD2_MAX_SLABS];
static const char *jbd2_slab_names[JBD2_MAX_SLABS] = {
"jbd2_1k", "jbd2_2k", "jbd2_4k", "jbd2_8k",
"jbd2_16k", "jbd2_32k", "jbd2_64k", "jbd2_128k"
};
static void jbd2_journal_destroy_slabs(void)
{
int i;
for (i = 0; i < JBD2_MAX_SLABS; i++) {
if (jbd2_slab[i])
kmem_cache_destroy(jbd2_slab[i]);
jbd2_slab[i] = NULL;
}
}
static int jbd2_journal_create_slab(size_t size)
{
static DEFINE_MUTEX(jbd2_slab_create_mutex);
int i = order_base_2(size) - 10;
size_t slab_size;
if (size == PAGE_SIZE)
return 0;
if (i >= JBD2_MAX_SLABS)
return -EINVAL;
if (unlikely(i < 0))
i = 0;
mutex_lock(&jbd2_slab_create_mutex);
if (jbd2_slab[i]) {
mutex_unlock(&jbd2_slab_create_mutex);
return 0; /* Already created */
}
slab_size = 1 << (i+10);
jbd2_slab[i] = kmem_cache_create(jbd2_slab_names[i], slab_size,
slab_size, 0, NULL);
mutex_unlock(&jbd2_slab_create_mutex);
if (!jbd2_slab[i]) {
printk(KERN_EMERG "JBD2: no memory for jbd2_slab cache\n");
return -ENOMEM;
}
return 0;
}
static struct kmem_cache *get_slab(size_t size)
{
int i = order_base_2(size) - 10;
BUG_ON(i >= JBD2_MAX_SLABS);
if (unlikely(i < 0))
i = 0;
BUG_ON(jbd2_slab[i] == NULL);
return jbd2_slab[i];
}
void *jbd2_alloc(size_t size, gfp_t flags)
{
void *ptr;
BUG_ON(size & (size-1)); /* Must be a power of 2 */
flags |= __GFP_REPEAT;
if (size == PAGE_SIZE)
ptr = (void *)__get_free_pages(flags, 0);
else if (size > PAGE_SIZE) {
int order = get_order(size);
if (order < 3)
ptr = (void *)__get_free_pages(flags, order);
else
ptr = vmalloc(size);
} else
ptr = kmem_cache_alloc(get_slab(size), flags);
/* Check alignment; SLUB has gotten this wrong in the past,
* and this can lead to user data corruption! */
BUG_ON(((unsigned long) ptr) & (size-1));
return ptr;
}
void jbd2_free(void *ptr, size_t size)
{
if (size == PAGE_SIZE) {
free_pages((unsigned long)ptr, 0);
return;
}
if (size > PAGE_SIZE) {
int order = get_order(size);
if (order < 3)
free_pages((unsigned long)ptr, order);
else
vfree(ptr);
return;
}
kmem_cache_free(get_slab(size), ptr);
};
/*
* Journal_head storage management
*/
static struct kmem_cache *jbd2_journal_head_cache;
#ifdef CONFIG_JBD2_DEBUG
static atomic_t nr_journal_heads = ATOMIC_INIT(0);
#endif
static int jbd2_journal_init_journal_head_cache(void)
{
int retval;
J_ASSERT(jbd2_journal_head_cache == NULL);
jbd2_journal_head_cache = kmem_cache_create("jbd2_journal_head",
sizeof(struct journal_head),
0, /* offset */
SLAB_TEMPORARY, /* flags */
NULL); /* ctor */
retval = 0;
if (!jbd2_journal_head_cache) {
retval = -ENOMEM;
printk(KERN_EMERG "JBD2: no memory for journal_head cache\n");
}
return retval;
}
static void jbd2_journal_destroy_journal_head_cache(void)
{
if (jbd2_journal_head_cache) {
kmem_cache_destroy(jbd2_journal_head_cache);
jbd2_journal_head_cache = NULL;
}
}
/*
* journal_head splicing and dicing
*/
static struct journal_head *journal_alloc_journal_head(void)
{
struct journal_head *ret;
#ifdef CONFIG_JBD2_DEBUG
atomic_inc(&nr_journal_heads);
#endif
ret = kmem_cache_zalloc(jbd2_journal_head_cache, GFP_NOFS);
if (!ret) {
jbd_debug(1, "out of memory for journal_head\n");
pr_notice_ratelimited("ENOMEM in %s, retrying.\n", __func__);
while (!ret) {
yield();
ret = kmem_cache_zalloc(jbd2_journal_head_cache, GFP_NOFS);
}
}
return ret;
}
static void journal_free_journal_head(struct journal_head *jh)
{
#ifdef CONFIG_JBD2_DEBUG
atomic_dec(&nr_journal_heads);
memset(jh, JBD2_POISON_FREE, sizeof(*jh));
#endif
kmem_cache_free(jbd2_journal_head_cache, jh);
}
/*
* A journal_head is attached to a buffer_head whenever JBD has an
* interest in the buffer.
*
* Whenever a buffer has an attached journal_head, its ->b_state:BH_JBD bit
* is set. This bit is tested in core kernel code where we need to take
* JBD-specific actions. Testing the zeroness of ->b_private is not reliable
* there.
*
* When a buffer has its BH_JBD bit set, its ->b_count is elevated by one.
*
* When a buffer has its BH_JBD bit set it is immune from being released by
* core kernel code, mainly via ->b_count.
*
* A journal_head is detached from its buffer_head when the journal_head's
* b_jcount reaches zero. Running transaction (b_transaction) and checkpoint
* transaction (b_cp_transaction) hold their references to b_jcount.
*
* Various places in the kernel want to attach a journal_head to a buffer_head
* _before_ attaching the journal_head to a transaction. To protect the
* journal_head in this situation, jbd2_journal_add_journal_head elevates the
* journal_head's b_jcount refcount by one. The caller must call
* jbd2_journal_put_journal_head() to undo this.
*
* So the typical usage would be:
*
* (Attach a journal_head if needed. Increments b_jcount)
* struct journal_head *jh = jbd2_journal_add_journal_head(bh);
* ...
* (Get another reference for transaction)
* jbd2_journal_grab_journal_head(bh);
* jh->b_transaction = xxx;
* (Put original reference)
* jbd2_journal_put_journal_head(jh);
*/
/*
* Give a buffer_head a journal_head.
*
* May sleep.
*/
struct journal_head *jbd2_journal_add_journal_head(struct buffer_head *bh)
{
struct journal_head *jh;
struct journal_head *new_jh = NULL;
repeat:
if (!buffer_jbd(bh))
new_jh = journal_alloc_journal_head();
jbd_lock_bh_journal_head(bh);
if (buffer_jbd(bh)) {
jh = bh2jh(bh);
} else {
J_ASSERT_BH(bh,
(atomic_read(&bh->b_count) > 0) ||
(bh->b_page && bh->b_page->mapping));
if (!new_jh) {
jbd_unlock_bh_journal_head(bh);
goto repeat;
}
jh = new_jh;
new_jh = NULL; /* We consumed it */
set_buffer_jbd(bh);
bh->b_private = jh;
jh->b_bh = bh;
get_bh(bh);
BUFFER_TRACE(bh, "added journal_head");
}
jh->b_jcount++;
jbd_unlock_bh_journal_head(bh);
if (new_jh)
journal_free_journal_head(new_jh);
return bh->b_private;
}
/*
* Grab a ref against this buffer_head's journal_head. If it ended up not
* having a journal_head, return NULL
*/
struct journal_head *jbd2_journal_grab_journal_head(struct buffer_head *bh)
{
struct journal_head *jh = NULL;
jbd_lock_bh_journal_head(bh);
if (buffer_jbd(bh)) {
jh = bh2jh(bh);
jh->b_jcount++;
}
jbd_unlock_bh_journal_head(bh);
return jh;
}
static void __journal_remove_journal_head(struct buffer_head *bh)
{
struct journal_head *jh = bh2jh(bh);
J_ASSERT_JH(jh, jh->b_jcount >= 0);
J_ASSERT_JH(jh, jh->b_transaction == NULL);
J_ASSERT_JH(jh, jh->b_next_transaction == NULL);
J_ASSERT_JH(jh, jh->b_cp_transaction == NULL);
J_ASSERT_JH(jh, jh->b_jlist == BJ_None);
J_ASSERT_BH(bh, buffer_jbd(bh));
J_ASSERT_BH(bh, jh2bh(jh) == bh);
BUFFER_TRACE(bh, "remove journal_head");
if (jh->b_frozen_data) {
printk(KERN_WARNING "%s: freeing b_frozen_data\n", __func__);
jbd2_free(jh->b_frozen_data, bh->b_size);
}
if (jh->b_committed_data) {
printk(KERN_WARNING "%s: freeing b_committed_data\n", __func__);
jbd2_free(jh->b_committed_data, bh->b_size);
}
bh->b_private = NULL;
jh->b_bh = NULL; /* debug, really */
clear_buffer_jbd(bh);
journal_free_journal_head(jh);
}
/*
* Drop a reference on the passed journal_head. If it fell to zero then
* release the journal_head from the buffer_head.
*/
void jbd2_journal_put_journal_head(struct journal_head *jh)
{
struct buffer_head *bh = jh2bh(jh);
jbd_lock_bh_journal_head(bh);
J_ASSERT_JH(jh, jh->b_jcount > 0);
--jh->b_jcount;
if (!jh->b_jcount) {
__journal_remove_journal_head(bh);
jbd_unlock_bh_journal_head(bh);
__brelse(bh);
} else
jbd_unlock_bh_journal_head(bh);
}
/*
* Initialize jbd inode head
*/
void jbd2_journal_init_jbd_inode(struct jbd2_inode *jinode, struct inode *inode)
{
jinode->i_transaction = NULL;
jinode->i_next_transaction = NULL;
jinode->i_vfs_inode = inode;
jinode->i_flags = 0;
INIT_LIST_HEAD(&jinode->i_list);
}
/*
* Function to be called before we start removing inode from memory (i.e.,
* clear_inode() is a fine place to be called from). It removes inode from
* transaction's lists.
*/
void jbd2_journal_release_jbd_inode(journal_t *journal,
struct jbd2_inode *jinode)
{
if (!journal)
return;
restart:
spin_lock(&journal->j_list_lock);
/* Is commit writing out inode - we have to wait */
if (test_bit(__JI_COMMIT_RUNNING, &jinode->i_flags)) {
wait_queue_head_t *wq;
DEFINE_WAIT_BIT(wait, &jinode->i_flags, __JI_COMMIT_RUNNING);
wq = bit_waitqueue(&jinode->i_flags, __JI_COMMIT_RUNNING);
prepare_to_wait(wq, &wait.wait, TASK_UNINTERRUPTIBLE);
spin_unlock(&journal->j_list_lock);
schedule();
finish_wait(wq, &wait.wait);
goto restart;
}
if (jinode->i_transaction) {
list_del(&jinode->i_list);
jinode->i_transaction = NULL;
}
spin_unlock(&journal->j_list_lock);
}
#ifdef CONFIG_PROC_FS
#define JBD2_STATS_PROC_NAME "fs/jbd2"
static void __init jbd2_create_jbd_stats_proc_entry(void)
{
proc_jbd2_stats = proc_mkdir(JBD2_STATS_PROC_NAME, NULL);
}
static void __exit jbd2_remove_jbd_stats_proc_entry(void)
{
if (proc_jbd2_stats)
remove_proc_entry(JBD2_STATS_PROC_NAME, NULL);
}
#else
#define jbd2_create_jbd_stats_proc_entry() do {} while (0)
#define jbd2_remove_jbd_stats_proc_entry() do {} while (0)
#endif
struct kmem_cache *jbd2_handle_cache, *jbd2_inode_cache;
static int __init jbd2_journal_init_handle_cache(void)
{
jbd2_handle_cache = KMEM_CACHE(jbd2_journal_handle, SLAB_TEMPORARY);
if (jbd2_handle_cache == NULL) {
printk(KERN_EMERG "JBD2: failed to create handle cache\n");
return -ENOMEM;
}
jbd2_inode_cache = KMEM_CACHE(jbd2_inode, 0);
if (jbd2_inode_cache == NULL) {
printk(KERN_EMERG "JBD2: failed to create inode cache\n");
kmem_cache_destroy(jbd2_handle_cache);
return -ENOMEM;
}
return 0;
}
static void jbd2_journal_destroy_handle_cache(void)
{
if (jbd2_handle_cache)
kmem_cache_destroy(jbd2_handle_cache);
if (jbd2_inode_cache)
kmem_cache_destroy(jbd2_inode_cache);
}
/*
* Module startup and shutdown
*/
static int __init journal_init_caches(void)
{
int ret;
ret = jbd2_journal_init_revoke_caches();
if (ret == 0)
ret = jbd2_journal_init_journal_head_cache();
if (ret == 0)
ret = jbd2_journal_init_handle_cache();
if (ret == 0)
ret = jbd2_journal_init_transaction_cache();
return ret;
}
static void jbd2_journal_destroy_caches(void)
{
jbd2_journal_destroy_revoke_caches();
jbd2_journal_destroy_journal_head_cache();
jbd2_journal_destroy_handle_cache();
jbd2_journal_destroy_transaction_cache();
jbd2_journal_destroy_slabs();
}
static int __init journal_init(void)
{
int ret;
BUILD_BUG_ON(sizeof(struct journal_superblock_s) != 1024);
ret = journal_init_caches();
if (ret == 0) {
jbd2_create_jbd_stats_proc_entry();
} else {
jbd2_journal_destroy_caches();
}
return ret;
}
static void __exit journal_exit(void)
{
#ifdef CONFIG_JBD2_DEBUG
int n = atomic_read(&nr_journal_heads);
if (n)
printk(KERN_EMERG "JBD2: leaked %d journal_heads!\n", n);
#endif
jbd2_remove_jbd_stats_proc_entry();
jbd2_journal_destroy_caches();
}
MODULE_LICENSE("GPL");
module_init(journal_init);
module_exit(journal_exit);
Reference in New Issue View Git Blame Copy Permalink