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linux/fs/jbd2/commit.c
Linus Torvalds 7e0e7bd60d Merge tag 'vfs-7.2-rc1.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs 
Pull misc vfs updates from Christian Brauner:
 "Features:

   - Reduce pipe->mutex contention by pre-allocating pages outside the
     lock in anon_pipe_write().

     anon_pipe_write() called alloc_page() once per page while holding
     pipe->mutex. The allocation can sleep doing direct reclaim and runs
     memcg charging, which extends the critical section and stalls any
     concurrent reader on the same mutex. Now up to 8 pages are
     pre-allocated before the mutex is taken, leftovers are recycled
     into the per-pipe tmp_page[] cache before unlock, and any remainder
     is released after unlock, keeping the allocator out of the critical
     section on both sides. On a writers x readers sweep with 64KB
     writes against a 1 MB pipe throughput improves 6-28% and average
     write latency drops 5-22%; under memory pressure - when the cost of
     holding the mutex across reclaim is highest - throughput improves
     21-48% and latency drops 17-33%. The microbenchmark is added to
     selftests.

   - uaccess/sockptr: fix the ignored_trailing logic in
     copy_struct_to_user() to behave as documented and the usize check
     in copy_struct_from_sockptr() for user pointers, and add
     copy_struct_{from,to}_bounce_buffer() and copy_struct_to_sockptr()
     helpers for upcoming users (IPPROTO_SMBDIRECT, IPPROTO_QUIC).

   - bpf: add a sleepable bpf_real_inode() kfunc that resolves the real
     inode backing a dentry via d_real_inode(). On overlayfs the inode
     attached to the dentry doesn't carry the underlying device
     information; this is used by the filesystem restriction BPF program
     that was merged into systemd.

   - docs: add guidelines for submitting new filesystems, motivated by
     the maintenance burden abandoned and untestable filesystems impose
     on VFS developers, blocking infrastructure work like folio
     conversions and iomap migration.

  Fixes:

   - libfs: set SB_I_NOEXEC and SB_I_NODEV by default in init_pseudo()
     and drop the now-redundant assignments in callers. This began as a
     one-line dma-buf fix for a path_noexec() warning; a pseudo
     filesystem has no reason not to set SB_I_NOEXEC. All init_pseudo()
     callers were audited: the only visible effect is on dma-buf where
     SB_I_NOEXEC silences the warning.

   - Handle set_blocksize() failures in legacy filesystems (bfs, hpfs,
     qnx4, jfs, befs, affs, isofs, minix, ntfs3, omfs). Mounting a
     device with a sector size > PAGE_SIZE crashed roughly half of them;
     the rest had the same missing error handling pattern. Plus a
     follow-up releasing the superblock buffer_head when setting the
     minix v3 block size fails.

   - mount: honour SB_NOUSER in the new mount API.

   - fs/fcntl: fix a SOFTIRQ-unsafe lock order in fasync signaling by
     switching the process-group paths of send_sigio() and send_sigurg()
     from read_lock(&tasklist_lock) to RCU, matching the single-PID
     path.

   - vfs: add an FS_USERNS_DELEGATABLE flag and set it for NFS, fixing
     delegated NFS mounts (fsopen() in a container with the mount
     performed by a privileged daemon) that broke when non-init
     s_user_ns was tied to FS_USERNS_MOUNT.

   - selftests/namespaces: fix a hang in nsid_test where an unreaped
     grandchild kept the TAP pipe write-end open, a waitpid(-1) race in
     listns_efault_test, and a false FAIL on kernels without listns()
     where the tests should SKIP.

   - filelock: fix the break_lease() stub signature for
     CONFIG_FILE_LOCKING=n.

   - init/initramfs_test: wait for the async initramfs unpacking before
     running; the test and do_populate_rootfs() share the parser state.

   - fs/coredump: reduce redundant log noise in
     validate_coredump_safety().

   - iomap: pass the correct length to fserror_report_io() in
     __iomap_write_begin().

   - backing-file: fix the backing_file_open() kerneldoc.

  Cleanups:

   - initramfs: refactor the cpio hex header parsing to use hex2bin()
     instead of the hand-rolled simple_strntoul() which is reverted, and
     extend the initramfs KUnit tests to cover header fields with 0x
     prefixes.

   - Replace __get_free_pages() and friends with kmalloc()/kzalloc()
     across quota, proc, ocfs2/dlm, nilfs2, nfs, nfsd, libfs, jfs, jbd2,
     isofs, fuse, select, namespace, configfs, binfmt_misc, bfs, and the
     do_mounts init code - part of the larger work of replacing page
     allocator calls with kmalloc().

   - Use clear_and_wake_up_bit() in unlock_buffer() and
     journal_end_buffer_io_sync() instead of open-coding the sequence.

   - Drop unused VFS exports: unexport drop_super_exclusive(), remove
     start_removing_user_path_at(), and fold __start_removing_path()
     into start_removing_path().

   - fs/read_write: narrow the __kernel_write() export with
     EXPORT_SYMBOL_FOR_MODULES().

   - vfs: uapi: retire octal and hex constants in favor of (1 << n) for
     the O_ flags. Finding a free bit for a new flag across the
     architectures was needlessly hard with the mixed bases.

   - dcache: add extra sanity checks of dead dentries in dentry_free()
     via a new DENTRY_WARN_ONCE() that also prints d_flags.

   - iov_iter: use kmemdup_array() in dup_iter() to harden the
     allocation against multiplication overflow.

   - fs/pipe: write to ->poll_usage only once.

   - vfs: remove an always-taken if-branch in find_next_fd().

   - dcache: use kmalloc_flex() for struct external_name in __d_alloc().

   - namei: use QSTR() instead of QSTR_INIT() in path_pts().

   - sync_file_range: delete dead S_ISLNK code.

   - Comment fixes: retire a stale comment in fget_task_next() and fix
     assorted spelling mistakes"

* tag 'vfs-7.2-rc1.misc' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (73 commits)
  backing-file: fix backing_file_open() kerneldoc parameter
  iomap: pass the correct len to fserror_report_io in __iomap_write_begin
  vfs: add FS_USERNS_DELEGATABLE flag and set it for NFS
  filelock: fix break_lease() stub signature for CONFIG_FILE_LOCKING=n
  vfs: uapi: retire octal and hex numbers in favor of (1 << n) for O_ flags
  bpf: add bpf_real_inode() kfunc
  fs/read_write: Do not export __kernel_write() to the entire world
  libfs: drop redundant SB_I_NOEXEC/SB_I_NODEV in init_pseudo() callers
  libfs: set SB_I_NOEXEC and SB_I_NODEV by default in init_pseudo()
  mount: honour SB_NOUSER in the new mount API
  fs/fcntl: fix SOFTIRQ-unsafe lock order in fasync signaling
  selftests/pipe: add pipe_bench microbenchmark
  fs/pipe: pre-allocate pages outside pipe->mutex in anon_pipe_write
  fs: retire stale comment in fget_task_next()
  fs: fix spelling mistakes in comment
  bfs: replace get_zeroed_page() with kzalloc()
  binfmt_misc: replace __get_free_page() with kmalloc()
  configfs: replace __get_free_pages() with kzalloc()
  fs/namespace: use __getname() to allocate mntpath buffer
  fs/select: replace __get_free_page() with kmalloc()
  ...
2026-06-15 03:59:45 +05:30

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// SPDX-License-Identifier: GPL-2.0+
/*
* linux/fs/jbd2/commit.c
*
* Written by Stephen C. Tweedie <sct@redhat.com>, 1998
*
* Copyright 1998 Red Hat corp --- All Rights Reserved
*
* Journal commit routines for the generic filesystem journaling code;
* part of the ext2fs journaling system.
*/
#include <linux/time.h>
#include <linux/fs.h>
#include <linux/jbd2.h>
#include <linux/errno.h>
#include <linux/slab.h>
#include <linux/mm.h>
#include <linux/pagemap.h>
#include <linux/jiffies.h>
#include <linux/crc32.h>
#include <linux/writeback.h>
#include <linux/backing-dev.h>
#include <linux/bio.h>
#include <linux/blkdev.h>
#include <linux/bitops.h>
#include <trace/events/jbd2.h>
/*
* IO end handler for temporary buffer_heads handling writes to the journal.
*/
static void journal_end_buffer_io_sync(struct bio *bio)
{
struct buffer_head *bh;
bool uptodate = bio_endio_bh(bio, &bh);
struct buffer_head *orig_bh = bh->b_private;
BUFFER_TRACE(bh, "");
if (uptodate)
set_buffer_uptodate(bh);
else
clear_buffer_uptodate(bh);
if (orig_bh) {
clear_and_wake_up_bit(BH_Shadow, &orig_bh->b_state);
}
unlock_buffer(bh);
}
/*
* When an ext4 file is truncated, it is possible that some pages are not
* successfully freed, because they are attached to a committing transaction.
* After the transaction commits, these pages are left on the LRU, with no
* ->mapping, and with attached buffers. These pages are trivially reclaimable
* by the VM, but their apparent absence upsets the VM accounting, and it makes
* the numbers in /proc/meminfo look odd.
*
* So here, we have a buffer which has just come off the forget list. Look to
* see if we can strip all buffers from the backing page.
*
* Called under j_list_lock. The caller provided us with a ref against the
* buffer, and we drop that here.
*/
static void release_buffer_page(struct buffer_head *bh)
{
struct folio *folio;
if (buffer_dirty(bh))
goto nope;
if (atomic_read(&bh->b_count) != 1)
goto nope;
folio = bh->b_folio;
if (folio->mapping)
goto nope;
/* OK, it's a truncated page */
if (!folio_trylock(folio))
goto nope;
folio_get(folio);
__brelse(bh);
try_to_free_buffers(folio);
folio_unlock(folio);
folio_put(folio);
return;
nope:
__brelse(bh);
}
static void jbd2_commit_block_csum_set(journal_t *j, struct buffer_head *bh)
{
struct commit_header *h;
__u32 csum;
if (!jbd2_journal_has_csum_v2or3(j))
return;
h = (struct commit_header *)(bh->b_data);
h->h_chksum_type = 0;
h->h_chksum_size = 0;
h->h_chksum[0] = 0;
csum = jbd2_chksum(j->j_csum_seed, bh->b_data, j->j_blocksize);
h->h_chksum[0] = cpu_to_be32(csum);
}
/*
* Done it all: now submit the commit record. We should have
* cleaned up our previous buffers by now, so if we are in abort
* mode we can now just skip the rest of the journal write
* entirely.
*
* Returns 1 if the journal needs to be aborted or 0 on success
*/
static int journal_submit_commit_record(journal_t *journal,
transaction_t *commit_transaction,
struct buffer_head **cbh,
__u32 crc32_sum)
{
struct commit_header *tmp;
struct buffer_head *bh;
struct timespec64 now;
blk_opf_t write_flags = REQ_OP_WRITE | JBD2_JOURNAL_REQ_FLAGS;
*cbh = NULL;
if (is_journal_aborted(journal))
return 0;
bh = jbd2_journal_get_descriptor_buffer(commit_transaction,
JBD2_COMMIT_BLOCK);
if (!bh)
return 1;
tmp = (struct commit_header *)bh->b_data;
ktime_get_coarse_real_ts64(&now);
tmp->h_commit_sec = cpu_to_be64(now.tv_sec);
tmp->h_commit_nsec = cpu_to_be32(now.tv_nsec);
if (jbd2_has_feature_checksum(journal)) {
tmp->h_chksum_type = JBD2_CRC32_CHKSUM;
tmp->h_chksum_size = JBD2_CRC32_CHKSUM_SIZE;
tmp->h_chksum[0] = cpu_to_be32(crc32_sum);
}
jbd2_commit_block_csum_set(journal, bh);
BUFFER_TRACE(bh, "submit commit block");
lock_buffer(bh);
clear_buffer_dirty(bh);
set_buffer_uptodate(bh);
if (journal->j_flags & JBD2_BARRIER &&
!jbd2_has_feature_async_commit(journal))
write_flags |= REQ_PREFLUSH | REQ_FUA;
bh_submit(bh, write_flags, journal_end_buffer_io_sync);
*cbh = bh;
return 0;
}
/*
* This function along with journal_submit_commit_record
* allows to write the commit record asynchronously.
*/
static int journal_wait_on_commit_record(journal_t *journal,
struct buffer_head *bh)
{
int ret = 0;
clear_buffer_dirty(bh);
wait_on_buffer(bh);
if (unlikely(!buffer_uptodate(bh)))
ret = -EIO;
put_bh(bh); /* One for getblk() */
return ret;
}
/* Send all the data buffers related to an inode */
int jbd2_submit_inode_data(journal_t *journal, struct jbd2_inode *jinode)
{
unsigned long flags;
if (!jinode)
return 0;
flags = READ_ONCE(jinode->i_flags);
if (!(flags & JI_WRITE_DATA))
return 0;
trace_jbd2_submit_inode_data(jinode->i_vfs_inode);
return journal->j_submit_inode_data_buffers(jinode);
}
EXPORT_SYMBOL(jbd2_submit_inode_data);
int jbd2_wait_inode_data(journal_t *journal, struct jbd2_inode *jinode)
{
struct address_space *mapping;
struct inode *inode;
unsigned long flags;
loff_t start_byte, end_byte;
if (!jinode)
return 0;
flags = READ_ONCE(jinode->i_flags);
if (!(flags & JI_WAIT_DATA))
return 0;
inode = jinode->i_vfs_inode;
if (!inode)
return 0;
mapping = inode->i_mapping;
if (!mapping)
return 0;
if (!jbd2_jinode_get_dirty_range(jinode, &start_byte, &end_byte))
return 0;
return filemap_fdatawait_range_keep_errors(
mapping, start_byte, end_byte);
}
EXPORT_SYMBOL(jbd2_wait_inode_data);
/*
* Submit all the data buffers of inode associated with the transaction to
* disk.
*
* We are in a committing transaction. Therefore no new inode can be added to
* our inode list. We use JI_COMMIT_RUNNING flag to protect inode we currently
* operate on from being released while we write out pages.
*/
static int journal_submit_data_buffers(journal_t *journal,
transaction_t *commit_transaction)
{
struct jbd2_inode *jinode;
int err, ret = 0;
spin_lock(&journal->j_list_lock);
list_for_each_entry(jinode, &commit_transaction->t_inode_list, i_list) {
if (!(jinode->i_flags & JI_WRITE_DATA))
continue;
WRITE_ONCE(jinode->i_flags,
jinode->i_flags | JI_COMMIT_RUNNING);
spin_unlock(&journal->j_list_lock);
/* submit the inode data buffers. */
trace_jbd2_submit_inode_data(jinode->i_vfs_inode);
if (journal->j_submit_inode_data_buffers) {
err = journal->j_submit_inode_data_buffers(jinode);
if (!ret)
ret = err;
}
spin_lock(&journal->j_list_lock);
J_ASSERT(jinode->i_transaction == commit_transaction);
WRITE_ONCE(jinode->i_flags,
jinode->i_flags & ~JI_COMMIT_RUNNING);
smp_mb();
wake_up_bit(&jinode->i_flags, __JI_COMMIT_RUNNING);
}
spin_unlock(&journal->j_list_lock);
return ret;
}
int jbd2_journal_finish_inode_data_buffers(struct jbd2_inode *jinode)
{
struct address_space *mapping = jinode->i_vfs_inode->i_mapping;
loff_t start_byte, end_byte;
if (!jbd2_jinode_get_dirty_range(jinode, &start_byte, &end_byte))
return 0;
return filemap_fdatawait_range_keep_errors(mapping,
start_byte, end_byte);
}
/*
* Wait for data submitted for writeout, refile inodes to proper
* transaction if needed.
*
*/
static int journal_finish_inode_data_buffers(journal_t *journal,
transaction_t *commit_transaction)
{
struct jbd2_inode *jinode, *next_i;
int err, ret = 0;
/* For locking, see the comment in journal_submit_data_buffers() */
spin_lock(&journal->j_list_lock);
list_for_each_entry(jinode, &commit_transaction->t_inode_list, i_list) {
if (!(jinode->i_flags & JI_WAIT_DATA))
continue;
WRITE_ONCE(jinode->i_flags, jinode->i_flags | JI_COMMIT_RUNNING);
spin_unlock(&journal->j_list_lock);
/* wait for the inode data buffers writeout. */
if (journal->j_finish_inode_data_buffers) {
err = journal->j_finish_inode_data_buffers(jinode);
if (!ret)
ret = err;
}
cond_resched();
spin_lock(&journal->j_list_lock);
WRITE_ONCE(jinode->i_flags, jinode->i_flags & ~JI_COMMIT_RUNNING);
smp_mb();
wake_up_bit(&jinode->i_flags, __JI_COMMIT_RUNNING);
}
/* Now refile inode to proper lists */
list_for_each_entry_safe(jinode, next_i,
&commit_transaction->t_inode_list, i_list) {
list_del(&jinode->i_list);
if (jinode->i_next_transaction) {
jinode->i_transaction = jinode->i_next_transaction;
jinode->i_next_transaction = NULL;
list_add(&jinode->i_list,
&jinode->i_transaction->t_inode_list);
} else {
jinode->i_transaction = NULL;
WRITE_ONCE(jinode->i_dirty_start_page, 0);
WRITE_ONCE(jinode->i_dirty_end_page, 0);
}
}
spin_unlock(&journal->j_list_lock);
return ret;
}
static __u32 jbd2_checksum_data(__u32 crc32_sum, struct buffer_head *bh)
{
char *addr;
__u32 checksum;
addr = kmap_local_folio(bh->b_folio, bh_offset(bh));
checksum = crc32_be(crc32_sum, addr, bh->b_size);
kunmap_local(addr);
return checksum;
}
static void write_tag_block(journal_t *j, journal_block_tag_t *tag,
unsigned long long block)
{
tag->t_blocknr = cpu_to_be32(block & (u32)~0);
if (jbd2_has_feature_64bit(j))
tag->t_blocknr_high = cpu_to_be32((block >> 31) >> 1);
}
static void jbd2_block_tag_csum_set(journal_t *j, journal_block_tag_t *tag,
struct buffer_head *bh, __u32 sequence)
{
journal_block_tag3_t *tag3 = (journal_block_tag3_t *)tag;
__u8 *addr;
__u32 csum32;
__be32 seq;
if (!jbd2_journal_has_csum_v2or3(j))
return;
seq = cpu_to_be32(sequence);
addr = kmap_local_folio(bh->b_folio, bh_offset(bh));
csum32 = jbd2_chksum(j->j_csum_seed, (__u8 *)&seq, sizeof(seq));
csum32 = jbd2_chksum(csum32, addr, bh->b_size);
kunmap_local(addr);
if (jbd2_has_feature_csum3(j))
tag3->t_checksum = cpu_to_be32(csum32);
else
tag->t_checksum = cpu_to_be16(csum32);
}
/*
* jbd2_journal_commit_transaction
*
* The primary function for committing a transaction to the log. This
* function is called by the journal thread to begin a complete commit.
*/
void jbd2_journal_commit_transaction(journal_t *journal)
{
struct transaction_stats_s stats;
transaction_t *commit_transaction;
struct journal_head *jh;
struct buffer_head *descriptor;
struct buffer_head **wbuf = journal->j_wbuf;
int bufs;
int escape;
int err;
unsigned long long blocknr;
ktime_t start_time;
u64 commit_time;
char *tagp = NULL;
journal_block_tag_t *tag = NULL;
int space_left = 0;
int first_tag = 0;
int tag_flag;
int i;
int tag_bytes = journal_tag_bytes(journal);
struct buffer_head *cbh = NULL; /* For transactional checksums */
__u32 crc32_sum = ~0;
struct blk_plug plug;
/* Tail of the journal */
unsigned long first_block;
tid_t first_tid;
int update_tail;
int csum_size = 0;
LIST_HEAD(io_bufs);
LIST_HEAD(log_bufs);
if (jbd2_journal_has_csum_v2or3(journal))
csum_size = sizeof(struct jbd2_journal_block_tail);
/*
* First job: lock down the current transaction and wait for
* all outstanding updates to complete.
*/
/* Do we need to erase the effects of a prior jbd2_journal_flush? */
if (journal->j_flags & JBD2_FLUSHED) {
jbd2_debug(3, "super block updated\n");
mutex_lock_io(&journal->j_checkpoint_mutex);
/*
* We hold j_checkpoint_mutex so tail cannot change under us.
* We don't need any special data guarantees for writing sb
* since journal is empty and it is ok for write to be
* flushed only with transaction commit.
*/
jbd2_journal_update_sb_log_tail(journal,
journal->j_tail_sequence,
journal->j_tail, 0);
mutex_unlock(&journal->j_checkpoint_mutex);
} else {
jbd2_debug(3, "superblock not updated\n");
}
J_ASSERT(journal->j_running_transaction != NULL);
J_ASSERT(journal->j_committing_transaction == NULL);
write_lock(&journal->j_state_lock);
journal->j_flags |= JBD2_FULL_COMMIT_ONGOING;
while (journal->j_flags & JBD2_FAST_COMMIT_ONGOING) {
DEFINE_WAIT(wait);
prepare_to_wait(&journal->j_fc_wait, &wait,
TASK_UNINTERRUPTIBLE);
write_unlock(&journal->j_state_lock);
schedule();
write_lock(&journal->j_state_lock);
finish_wait(&journal->j_fc_wait, &wait);
/*
* TODO: by blocking fast commits here, we are increasing
* fsync() latency slightly. Strictly speaking, we don't need
* to block fast commits until the transaction enters T_FLUSH
* state. So an optimization is possible where we block new fast
* commits here and wait for existing ones to complete
* just before we enter T_FLUSH. That way, the existing fast
* commits and this full commit can proceed parallely.
*/
}
write_unlock(&journal->j_state_lock);
commit_transaction = journal->j_running_transaction;
trace_jbd2_start_commit(journal, commit_transaction);
jbd2_debug(1, "JBD2: starting commit of transaction %d\n",
commit_transaction->t_tid);
write_lock(&journal->j_state_lock);
journal->j_fc_off = 0;
J_ASSERT(commit_transaction->t_state == T_RUNNING);
commit_transaction->t_state = T_LOCKED;
trace_jbd2_commit_locking(journal, commit_transaction);
stats.run.rs_wait = commit_transaction->t_max_wait;
stats.run.rs_request_delay = 0;
stats.run.rs_locked = jiffies;
if (commit_transaction->t_requested)
stats.run.rs_request_delay =
jbd2_time_diff(commit_transaction->t_requested,
stats.run.rs_locked);
stats.run.rs_running = jbd2_time_diff(commit_transaction->t_start,
stats.run.rs_locked);
// waits for any t_updates to finish
jbd2_journal_wait_updates(journal);
commit_transaction->t_state = T_SWITCH;
J_ASSERT (atomic_read(&commit_transaction->t_outstanding_credits) <=
journal->j_max_transaction_buffers);
/*
* First thing we are allowed to do is to discard any remaining
* BJ_Reserved buffers. Note, it is _not_ permissible to assume
* that there are no such buffers: if a large filesystem
* operation like a truncate needs to split itself over multiple
* transactions, then it may try to do a jbd2_journal_restart() while
* there are still BJ_Reserved buffers outstanding. These must
* be released cleanly from the current transaction.
*
* In this case, the filesystem must still reserve write access
* again before modifying the buffer in the new transaction, but
* we do not require it to remember exactly which old buffers it
* has reserved. This is consistent with the existing behaviour
* that multiple jbd2_journal_get_write_access() calls to the same
* buffer are perfectly permissible.
* We use journal->j_state_lock here to serialize processing of
* t_reserved_list with eviction of buffers from journal_unmap_buffer().
*/
while (commit_transaction->t_reserved_list) {
jh = commit_transaction->t_reserved_list;
JBUFFER_TRACE(jh, "reserved, unused: refile");
/*
* A jbd2_journal_get_undo_access()+jbd2_journal_release_buffer() may
* leave undo-committed data.
*/
if (jh->b_committed_data) {
struct buffer_head *bh = jh2bh(jh);
spin_lock(&jh->b_state_lock);
jbd2_free(jh->b_committed_data, bh->b_size);
jh->b_committed_data = NULL;
spin_unlock(&jh->b_state_lock);
}
jbd2_journal_refile_buffer(journal, jh);
}
write_unlock(&journal->j_state_lock);
/*
* Now try to drop any written-back buffers from the journal's
* checkpoint lists. We do this *before* commit because it potentially
* frees some memory
*/
spin_lock(&journal->j_list_lock);
__jbd2_journal_clean_checkpoint_list(journal, JBD2_SHRINK_BUSY_STOP);
spin_unlock(&journal->j_list_lock);
jbd2_debug(3, "JBD2: commit phase 1\n");
/*
* Clear revoked flag to reflect there is no revoked buffers
* in the next transaction which is going to be started.
*/
jbd2_clear_buffer_revoked_flags(journal);
/*
* Switch to a new revoke table.
*/
jbd2_journal_switch_revoke_table(journal);
write_lock(&journal->j_state_lock);
/*
* Reserved credits cannot be claimed anymore, free them
*/
atomic_sub(atomic_read(&journal->j_reserved_credits),
&commit_transaction->t_outstanding_credits);
trace_jbd2_commit_flushing(journal, commit_transaction);
stats.run.rs_flushing = jiffies;
stats.run.rs_locked = jbd2_time_diff(stats.run.rs_locked,
stats.run.rs_flushing);
commit_transaction->t_state = T_FLUSH;
journal->j_committing_transaction = commit_transaction;
journal->j_running_transaction = NULL;
start_time = ktime_get();
commit_transaction->t_log_start = journal->j_head;
wake_up_all(&journal->j_wait_transaction_locked);
write_unlock(&journal->j_state_lock);
jbd2_debug(3, "JBD2: commit phase 2a\n");
/*
* Now start flushing things to disk, in the order they appear
* on the transaction lists. Data blocks go first.
*/
err = journal_submit_data_buffers(journal, commit_transaction);
if (err)
jbd2_journal_abort(journal, err);
blk_start_plug(&plug);
jbd2_journal_write_revoke_records(commit_transaction, &log_bufs);
jbd2_debug(3, "JBD2: commit phase 2b\n");
/*
* Way to go: we have now written out all of the data for a
* transaction! Now comes the tricky part: we need to write out
* metadata. Loop over the transaction's entire buffer list:
*/
write_lock(&journal->j_state_lock);
commit_transaction->t_state = T_COMMIT;
write_unlock(&journal->j_state_lock);
trace_jbd2_commit_logging(journal, commit_transaction);
stats.run.rs_logging = jiffies;
stats.run.rs_flushing = jbd2_time_diff(stats.run.rs_flushing,
stats.run.rs_logging);
stats.run.rs_blocks = commit_transaction->t_nr_buffers;
stats.run.rs_blocks_logged = 0;
J_ASSERT(commit_transaction->t_nr_buffers <=
atomic_read(&commit_transaction->t_outstanding_credits));
bufs = 0;
descriptor = NULL;
while (commit_transaction->t_buffers) {
/* Find the next buffer to be journaled... */
jh = commit_transaction->t_buffers;
/* If we're in abort mode, we just un-journal the buffer and
release it. */
if (is_journal_aborted(journal)) {
clear_buffer_jbddirty(jh2bh(jh));
JBUFFER_TRACE(jh, "journal is aborting: refile");
jbd2_buffer_abort_trigger(jh,
jh->b_frozen_data ?
jh->b_frozen_triggers :
jh->b_triggers);
jbd2_journal_refile_buffer(journal, jh);
/* If that was the last one, we need to clean up
* any descriptor buffers which may have been
* already allocated, even if we are now
* aborting. */
if (!commit_transaction->t_buffers)
goto start_journal_io;
continue;
}
/* Make sure we have a descriptor block in which to
record the metadata buffer. */
if (!descriptor) {
J_ASSERT (bufs == 0);
jbd2_debug(4, "JBD2: get descriptor\n");
descriptor = jbd2_journal_get_descriptor_buffer(
commit_transaction,
JBD2_DESCRIPTOR_BLOCK);
if (!descriptor) {
jbd2_journal_abort(journal, -EIO);
continue;
}
jbd2_debug(4, "JBD2: got buffer %llu (%p)\n",
(unsigned long long)descriptor->b_blocknr,
descriptor->b_data);
tagp = &descriptor->b_data[sizeof(journal_header_t)];
space_left = descriptor->b_size -
sizeof(journal_header_t);
first_tag = 1;
set_buffer_jwrite(descriptor);
set_buffer_dirty(descriptor);
wbuf[bufs++] = descriptor;
/* Record it so that we can wait for IO
completion later */
BUFFER_TRACE(descriptor, "ph3: file as descriptor");
jbd2_file_log_bh(&log_bufs, descriptor);
}
/* Where is the buffer to be written? */
err = jbd2_journal_next_log_block(journal, &blocknr);
/* If the block mapping failed, just abandon the buffer
and repeat this loop: we'll fall into the
refile-on-abort condition above. */
if (err) {
jbd2_journal_abort(journal, err);
continue;
}
/*
* start_this_handle() uses t_outstanding_credits to determine
* the free space in the log.
*/
atomic_dec(&commit_transaction->t_outstanding_credits);
/* Bump b_count to prevent truncate from stumbling over
the shadowed buffer! @@@ This can go if we ever get
rid of the shadow pairing of buffers. */
atomic_inc(&jh2bh(jh)->b_count);
/*
* Make a temporary IO buffer with which to write it out
* (this will requeue the metadata buffer to BJ_Shadow).
*/
set_bit(BH_JWrite, &jh2bh(jh)->b_state);
JBUFFER_TRACE(jh, "ph3: write metadata");
escape = jbd2_journal_write_metadata_buffer(commit_transaction,
jh, &wbuf[bufs], blocknr);
jbd2_file_log_bh(&io_bufs, wbuf[bufs]);
/* Record the new block's tag in the current descriptor
buffer */
tag_flag = 0;
if (escape)
tag_flag |= JBD2_FLAG_ESCAPE;
if (!first_tag)
tag_flag |= JBD2_FLAG_SAME_UUID;
tag = (journal_block_tag_t *) tagp;
write_tag_block(journal, tag, jh2bh(jh)->b_blocknr);
tag->t_flags = cpu_to_be16(tag_flag);
jbd2_block_tag_csum_set(journal, tag, wbuf[bufs],
commit_transaction->t_tid);
tagp += tag_bytes;
space_left -= tag_bytes;
bufs++;
if (first_tag) {
memcpy (tagp, journal->j_uuid, 16);
tagp += 16;
space_left -= 16;
first_tag = 0;
}
/* If there's no more to do, or if the descriptor is full,
let the IO rip! */
if (bufs == journal->j_wbufsize ||
commit_transaction->t_buffers == NULL ||
space_left < tag_bytes + 16 + csum_size) {
jbd2_debug(4, "JBD2: Submit %d IOs\n", bufs);
/* Write an end-of-descriptor marker before
submitting the IOs. "tag" still points to
the last tag we set up. */
tag->t_flags |= cpu_to_be16(JBD2_FLAG_LAST_TAG);
start_journal_io:
if (descriptor)
jbd2_descriptor_block_csum_set(journal,
descriptor);
for (i = 0; i < bufs; i++) {
struct buffer_head *bh = wbuf[i];
/*
* Compute checksum.
*/
if (jbd2_has_feature_checksum(journal)) {
crc32_sum =
jbd2_checksum_data(crc32_sum, bh);
}
lock_buffer(bh);
clear_buffer_dirty(bh);
set_buffer_uptodate(bh);
bh_submit(bh,
REQ_OP_WRITE | JBD2_JOURNAL_REQ_FLAGS,
journal_end_buffer_io_sync);
}
cond_resched();
/* Force a new descriptor to be generated next
time round the loop. */
descriptor = NULL;
bufs = 0;
}
}
err = journal_finish_inode_data_buffers(journal, commit_transaction);
if (err) {
printk(KERN_WARNING
"JBD2: Detected IO errors %d while flushing file data on %s\n",
err, journal->j_devname);
err = 0;
}
/*
* Get current oldest transaction in the log before we issue flush
* to the filesystem device. After the flush we can be sure that
* blocks of all older transactions are checkpointed to persistent
* storage and we will be safe to update journal start in the
* superblock with the numbers we get here.
*/
update_tail =
jbd2_journal_get_log_tail(journal, &first_tid, &first_block);
write_lock(&journal->j_state_lock);
if (update_tail) {
long freed = first_block - journal->j_tail;
if (first_block < journal->j_tail)
freed += journal->j_last - journal->j_first;
/* Update tail only if we free significant amount of space */
if (freed < journal->j_max_transaction_buffers)
update_tail = 0;
}
J_ASSERT(commit_transaction->t_state == T_COMMIT);
commit_transaction->t_state = T_COMMIT_DFLUSH;
write_unlock(&journal->j_state_lock);
/*
* If the journal is not located on the file system device,
* then we must flush the file system device before we issue
* the commit record and update the journal tail sequence.
*/
if ((commit_transaction->t_need_data_flush || update_tail) &&
(journal->j_fs_dev != journal->j_dev) &&
(journal->j_flags & JBD2_BARRIER))
blkdev_issue_flush(journal->j_fs_dev);
/* Done it all: now write the commit record asynchronously. */
if (jbd2_has_feature_async_commit(journal)) {
err = journal_submit_commit_record(journal, commit_transaction,
&cbh, crc32_sum);
if (err)
jbd2_journal_abort(journal, err);
}
blk_finish_plug(&plug);
/* Lo and behold: we have just managed to send a transaction to
the log. Before we can commit it, wait for the IO so far to
complete. Control buffers being written are on the
transaction's t_log_list queue, and metadata buffers are on
the io_bufs list.
Wait for the buffers in reverse order. That way we are
less likely to be woken up until all IOs have completed, and
so we incur less scheduling load.
*/
jbd2_debug(3, "JBD2: commit phase 3\n");
while (!list_empty(&io_bufs)) {
struct buffer_head *bh = list_entry(io_bufs.prev,
struct buffer_head,
b_assoc_buffers);
wait_on_buffer(bh);
cond_resched();
if (unlikely(!buffer_uptodate(bh)))
err = -EIO;
jbd2_unfile_log_bh(bh);
stats.run.rs_blocks_logged++;
/*
* The list contains temporary buffer heads created by
* jbd2_journal_write_metadata_buffer().
*/
BUFFER_TRACE(bh, "dumping temporary bh");
__brelse(bh);
J_ASSERT_BH(bh, atomic_read(&bh->b_count) == 0);
free_buffer_head(bh);
/* We also have to refile the corresponding shadowed buffer */
jh = commit_transaction->t_shadow_list->b_tprev;
bh = jh2bh(jh);
clear_buffer_jwrite(bh);
J_ASSERT_BH(bh, buffer_jbddirty(bh));
J_ASSERT_BH(bh, !buffer_shadow(bh));
/* The metadata is now released for reuse, but we need
to remember it against this transaction so that when
we finally commit, we can do any checkpointing
required. */
JBUFFER_TRACE(jh, "file as BJ_Forget");
jbd2_journal_file_buffer(jh, commit_transaction, BJ_Forget);
JBUFFER_TRACE(jh, "brelse shadowed buffer");
__brelse(bh);
}
J_ASSERT (commit_transaction->t_shadow_list == NULL);
jbd2_debug(3, "JBD2: commit phase 4\n");
/* Here we wait for the revoke record and descriptor record buffers */
while (!list_empty(&log_bufs)) {
struct buffer_head *bh;
bh = list_entry(log_bufs.prev, struct buffer_head, b_assoc_buffers);
wait_on_buffer(bh);
cond_resched();
if (unlikely(!buffer_uptodate(bh)))
err = -EIO;
BUFFER_TRACE(bh, "ph5: control buffer writeout done: unfile");
clear_buffer_jwrite(bh);
jbd2_unfile_log_bh(bh);
stats.run.rs_blocks_logged++;
__brelse(bh); /* One for getblk */
/* AKPM: bforget here */
}
if (err)
jbd2_journal_abort(journal, err);
jbd2_debug(3, "JBD2: commit phase 5\n");
write_lock(&journal->j_state_lock);
J_ASSERT(commit_transaction->t_state == T_COMMIT_DFLUSH);
commit_transaction->t_state = T_COMMIT_JFLUSH;
write_unlock(&journal->j_state_lock);
if (!jbd2_has_feature_async_commit(journal)) {
err = journal_submit_commit_record(journal, commit_transaction,
&cbh, crc32_sum);
if (err)
jbd2_journal_abort(journal, err);
}
if (cbh)
err = journal_wait_on_commit_record(journal, cbh);
stats.run.rs_blocks_logged++;
if (jbd2_has_feature_async_commit(journal) &&
journal->j_flags & JBD2_BARRIER) {
blkdev_issue_flush(journal->j_dev);
}
if (err)
jbd2_journal_abort(journal, err);
WARN_ON_ONCE(
atomic_read(&commit_transaction->t_outstanding_credits) < 0);
/*
* Now disk caches for filesystem device are flushed so we are safe to
* erase checkpointed transactions from the log by updating journal
* superblock.
*/
if (update_tail)
jbd2_update_log_tail(journal, first_tid, first_block);
/* End of a transaction! Finally, we can do checkpoint
processing: any buffers committed as a result of this
transaction can be removed from any checkpoint list it was on
before. */
jbd2_debug(3, "JBD2: commit phase 6\n");
J_ASSERT(list_empty(&commit_transaction->t_inode_list));
J_ASSERT(commit_transaction->t_buffers == NULL);
J_ASSERT(commit_transaction->t_checkpoint_list == NULL);
J_ASSERT(commit_transaction->t_shadow_list == NULL);
restart_loop:
/*
* As there are other places (journal_unmap_buffer()) adding buffers
* to this list we have to be careful and hold the j_list_lock.
*/
spin_lock(&journal->j_list_lock);
while (commit_transaction->t_forget) {
transaction_t *cp_transaction;
struct buffer_head *bh;
int try_to_free = 0;
bool drop_ref;
jh = commit_transaction->t_forget;
spin_unlock(&journal->j_list_lock);
bh = jh2bh(jh);
/*
* Get a reference so that bh cannot be freed before we are
* done with it.
*/
get_bh(bh);
spin_lock(&jh->b_state_lock);
J_ASSERT_JH(jh, jh->b_transaction == commit_transaction);
/*
* If there is undo-protected committed data against
* this buffer, then we can remove it now. If it is a
* buffer needing such protection, the old frozen_data
* field now points to a committed version of the
* buffer, so rotate that field to the new committed
* data.
*
* Otherwise, we can just throw away the frozen data now.
*
* We also know that the frozen data has already fired
* its triggers if they exist, so we can clear that too.
*/
if (jh->b_committed_data) {
jbd2_free(jh->b_committed_data, bh->b_size);
jh->b_committed_data = NULL;
if (jh->b_frozen_data) {
jh->b_committed_data = jh->b_frozen_data;
jh->b_frozen_data = NULL;
jh->b_frozen_triggers = NULL;
}
} else if (jh->b_frozen_data) {
jbd2_free(jh->b_frozen_data, bh->b_size);
jh->b_frozen_data = NULL;
jh->b_frozen_triggers = NULL;
}
spin_lock(&journal->j_list_lock);
cp_transaction = jh->b_cp_transaction;
if (cp_transaction) {
JBUFFER_TRACE(jh, "remove from old cp transaction");
cp_transaction->t_chp_stats.cs_dropped++;
__jbd2_journal_remove_checkpoint(jh);
}
/* Only re-checkpoint the buffer_head if it is marked
* dirty. If the buffer was added to the BJ_Forget list
* by jbd2_journal_forget, it may no longer be dirty and
* there's no point in keeping a checkpoint record for
* it. */
/*
* A buffer which has been freed while still being journaled
* by a previous transaction, refile the buffer to BJ_Forget of
* the running transaction. If the just committed transaction
* contains "add to orphan" operation, we can completely
* invalidate the buffer now. We are rather through in that
* since the buffer may be still accessible when blocksize <
* pagesize and it is attached to the last partial page.
*/
if (buffer_freed(bh) && !jh->b_next_transaction) {
struct address_space *mapping;
clear_buffer_freed(bh);
clear_buffer_jbddirty(bh);
/*
* Block device buffers need to stay mapped all the
* time, so it is enough to clear buffer_jbddirty and
* buffer_freed bits. For the file mapping buffers (i.e.
* journalled data) we need to unmap buffer and clear
* more bits. We also need to be careful about the check
* because the data page mapping can get cleared under
* our hands. Note that if mapping == NULL, we don't
* need to make buffer unmapped because the page is
* already detached from the mapping and buffers cannot
* get reused.
*/
mapping = READ_ONCE(bh->b_folio->mapping);
if (mapping && !sb_is_blkdev_sb(mapping->host->i_sb)) {
clear_buffer_mapped(bh);
clear_buffer_new(bh);
clear_buffer_req(bh);
bh->b_bdev = NULL;
}
}
if (buffer_jbddirty(bh)) {
JBUFFER_TRACE(jh, "add to new checkpointing trans");
__jbd2_journal_insert_checkpoint(jh, commit_transaction);
if (is_journal_aborted(journal))
clear_buffer_jbddirty(bh);
} else {
J_ASSERT_BH(bh, !buffer_dirty(bh));
/*
* The buffer on BJ_Forget list and not jbddirty means
* it has been freed by this transaction and hence it
* could not have been reallocated until this
* transaction has committed. *BUT* it could be
* reallocated once we have written all the data to
* disk and before we process the buffer on BJ_Forget
* list.
*/
if (!jh->b_next_transaction)
try_to_free = 1;
}
JBUFFER_TRACE(jh, "refile or unfile buffer");
drop_ref = __jbd2_journal_refile_buffer(jh);
spin_unlock(&jh->b_state_lock);
if (drop_ref)
jbd2_journal_put_journal_head(jh);
if (try_to_free)
release_buffer_page(bh); /* Drops bh reference */
else
__brelse(bh);
cond_resched_lock(&journal->j_list_lock);
}
spin_unlock(&journal->j_list_lock);
/*
* This is a bit sleazy. We use j_list_lock to protect transition
* of a transaction into T_FINISHED state and calling
* __jbd2_journal_drop_transaction(). Otherwise we could race with
* other checkpointing code processing the transaction...
*/
write_lock(&journal->j_state_lock);
spin_lock(&journal->j_list_lock);
/*
* Now recheck if some buffers did not get attached to the transaction
* while the lock was dropped...
*/
if (commit_transaction->t_forget) {
spin_unlock(&journal->j_list_lock);
write_unlock(&journal->j_state_lock);
goto restart_loop;
}
/* Add the transaction to the checkpoint list
* __journal_remove_checkpoint() can not destroy transaction
* under us because it is not marked as T_FINISHED yet */
if (journal->j_checkpoint_transactions == NULL) {
journal->j_checkpoint_transactions = commit_transaction;
commit_transaction->t_cpnext = commit_transaction;
commit_transaction->t_cpprev = commit_transaction;
} else {
commit_transaction->t_cpnext =
journal->j_checkpoint_transactions;
commit_transaction->t_cpprev =
commit_transaction->t_cpnext->t_cpprev;
commit_transaction->t_cpnext->t_cpprev =
commit_transaction;
commit_transaction->t_cpprev->t_cpnext =
commit_transaction;
}
spin_unlock(&journal->j_list_lock);
/* Done with this transaction! */
jbd2_debug(3, "JBD2: commit phase 7\n");
J_ASSERT(commit_transaction->t_state == T_COMMIT_JFLUSH);
commit_transaction->t_start = jiffies;
stats.run.rs_logging = jbd2_time_diff(stats.run.rs_logging,
commit_transaction->t_start);
/*
* File the transaction statistics
*/
stats.ts_tid = commit_transaction->t_tid;
stats.run.rs_handle_count =
atomic_read(&commit_transaction->t_handle_count);
trace_jbd2_run_stats(journal->j_fs_dev->bd_dev,
commit_transaction->t_tid, &stats.run);
stats.ts_requested = (commit_transaction->t_requested) ? 1 : 0;
commit_transaction->t_state = T_COMMIT_CALLBACK;
J_ASSERT(commit_transaction == journal->j_committing_transaction);
WRITE_ONCE(journal->j_commit_sequence, commit_transaction->t_tid);
journal->j_committing_transaction = NULL;
commit_time = ktime_to_ns(ktime_sub(ktime_get(), start_time));
/*
* weight the commit time higher than the average time so we don't
* react too strongly to vast changes in the commit time
*/
if (likely(journal->j_average_commit_time))
journal->j_average_commit_time = (commit_time +
journal->j_average_commit_time*3) / 4;
else
journal->j_average_commit_time = commit_time;
write_unlock(&journal->j_state_lock);
if (journal->j_commit_callback)
journal->j_commit_callback(journal, commit_transaction);
if (journal->j_fc_cleanup_callback)
journal->j_fc_cleanup_callback(journal, 1, commit_transaction->t_tid);
trace_jbd2_end_commit(journal, commit_transaction);
jbd2_debug(1, "JBD2: commit %d complete, head %d\n",
journal->j_commit_sequence, journal->j_tail_sequence);
write_lock(&journal->j_state_lock);
journal->j_flags &= ~JBD2_FULL_COMMIT_ONGOING;
journal->j_flags &= ~JBD2_FAST_COMMIT_ONGOING;
spin_lock(&journal->j_list_lock);
commit_transaction->t_state = T_FINISHED;
/* Check if the transaction can be dropped now that we are finished */
if (commit_transaction->t_checkpoint_list == NULL) {
__jbd2_journal_drop_transaction(journal, commit_transaction);
jbd2_journal_free_transaction(commit_transaction);
}
spin_unlock(&journal->j_list_lock);
write_unlock(&journal->j_state_lock);
wake_up(&journal->j_wait_done_commit);
wake_up(&journal->j_fc_wait);
/*
* Calculate overall stats
*/
spin_lock(&journal->j_history_lock);
journal->j_stats.ts_tid++;
journal->j_stats.ts_requested += stats.ts_requested;
journal->j_stats.run.rs_wait += stats.run.rs_wait;
journal->j_stats.run.rs_request_delay += stats.run.rs_request_delay;
journal->j_stats.run.rs_running += stats.run.rs_running;
journal->j_stats.run.rs_locked += stats.run.rs_locked;
journal->j_stats.run.rs_flushing += stats.run.rs_flushing;
journal->j_stats.run.rs_logging += stats.run.rs_logging;
journal->j_stats.run.rs_handle_count += stats.run.rs_handle_count;
journal->j_stats.run.rs_blocks += stats.run.rs_blocks;
journal->j_stats.run.rs_blocks_logged += stats.run.rs_blocks_logged;
spin_unlock(&journal->j_history_lock);
}
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