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linux-next/fs/ext4/ext4_jbd2.c
Jan Kara a413036791 ext4: Provide function to handle transaction restarts
Provide ext4_journal_ensure_credits_fn() function to ensure transaction
has given amount of credits and call helper function to prepare for
restarting a transaction. This allows to remove some boilerplate code
from various places, add proper error handling for the case where
transaction extension or restart fails, and reduces following changes
needed for proper revoke record reservation tracking.

Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20191105164437.32602-10-jack@suse.cz
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
2019-11-05 16:00:48 -05:00

344 lines
8.3 KiB
C

// SPDX-License-Identifier: GPL-2.0
/*
* Interface between ext4 and JBD
*/
#include "ext4_jbd2.h"
#include <trace/events/ext4.h>
/* Just increment the non-pointer handle value */
static handle_t *ext4_get_nojournal(void)
{
handle_t *handle = current->journal_info;
unsigned long ref_cnt = (unsigned long)handle;
BUG_ON(ref_cnt >= EXT4_NOJOURNAL_MAX_REF_COUNT);
ref_cnt++;
handle = (handle_t *)ref_cnt;
current->journal_info = handle;
return handle;
}
/* Decrement the non-pointer handle value */
static void ext4_put_nojournal(handle_t *handle)
{
unsigned long ref_cnt = (unsigned long)handle;
BUG_ON(ref_cnt == 0);
ref_cnt--;
handle = (handle_t *)ref_cnt;
current->journal_info = handle;
}
/*
* Wrappers for jbd2_journal_start/end.
*/
static int ext4_journal_check_start(struct super_block *sb)
{
journal_t *journal;
might_sleep();
if (unlikely(ext4_forced_shutdown(EXT4_SB(sb))))
return -EIO;
if (sb_rdonly(sb))
return -EROFS;
WARN_ON(sb->s_writers.frozen == SB_FREEZE_COMPLETE);
journal = EXT4_SB(sb)->s_journal;
/*
* Special case here: if the journal has aborted behind our
* backs (eg. EIO in the commit thread), then we still need to
* take the FS itself readonly cleanly.
*/
if (journal && is_journal_aborted(journal)) {
ext4_abort(sb, "Detected aborted journal");
return -EROFS;
}
return 0;
}
handle_t *__ext4_journal_start_sb(struct super_block *sb, unsigned int line,
int type, int blocks, int rsv_blocks)
{
journal_t *journal;
int err;
trace_ext4_journal_start(sb, blocks, rsv_blocks, _RET_IP_);
err = ext4_journal_check_start(sb);
if (err < 0)
return ERR_PTR(err);
journal = EXT4_SB(sb)->s_journal;
if (!journal)
return ext4_get_nojournal();
return jbd2__journal_start(journal, blocks, rsv_blocks, GFP_NOFS,
type, line);
}
int __ext4_journal_stop(const char *where, unsigned int line, handle_t *handle)
{
struct super_block *sb;
int err;
int rc;
if (!ext4_handle_valid(handle)) {
ext4_put_nojournal(handle);
return 0;
}
err = handle->h_err;
if (!handle->h_transaction) {
rc = jbd2_journal_stop(handle);
return err ? err : rc;
}
sb = handle->h_transaction->t_journal->j_private;
rc = jbd2_journal_stop(handle);
if (!err)
err = rc;
if (err)
__ext4_std_error(sb, where, line, err);
return err;
}
handle_t *__ext4_journal_start_reserved(handle_t *handle, unsigned int line,
int type)
{
struct super_block *sb;
int err;
if (!ext4_handle_valid(handle))
return ext4_get_nojournal();
sb = handle->h_journal->j_private;
trace_ext4_journal_start_reserved(sb, handle->h_buffer_credits,
_RET_IP_);
err = ext4_journal_check_start(sb);
if (err < 0) {
jbd2_journal_free_reserved(handle);
return ERR_PTR(err);
}
err = jbd2_journal_start_reserved(handle, type, line);
if (err < 0)
return ERR_PTR(err);
return handle;
}
int __ext4_journal_ensure_credits(handle_t *handle, int check_cred,
int extend_cred)
{
if (!ext4_handle_valid(handle))
return 0;
if (handle->h_buffer_credits >= check_cred)
return 0;
return ext4_journal_extend(handle,
extend_cred - handle->h_buffer_credits);
}
static void ext4_journal_abort_handle(const char *caller, unsigned int line,
const char *err_fn,
struct buffer_head *bh,
handle_t *handle, int err)
{
char nbuf[16];
const char *errstr = ext4_decode_error(NULL, err, nbuf);
BUG_ON(!ext4_handle_valid(handle));
if (bh)
BUFFER_TRACE(bh, "abort");
if (!handle->h_err)
handle->h_err = err;
if (is_handle_aborted(handle))
return;
printk(KERN_ERR "EXT4-fs: %s:%d: aborting transaction: %s in %s\n",
caller, line, errstr, err_fn);
jbd2_journal_abort_handle(handle);
}
int __ext4_journal_get_write_access(const char *where, unsigned int line,
handle_t *handle, struct buffer_head *bh)
{
int err = 0;
might_sleep();
if (ext4_handle_valid(handle)) {
err = jbd2_journal_get_write_access(handle, bh);
if (err)
ext4_journal_abort_handle(where, line, __func__, bh,
handle, err);
}
return err;
}
/*
* The ext4 forget function must perform a revoke if we are freeing data
* which has been journaled. Metadata (eg. indirect blocks) must be
* revoked in all cases.
*
* "bh" may be NULL: a metadata block may have been freed from memory
* but there may still be a record of it in the journal, and that record
* still needs to be revoked.
*
* If the handle isn't valid we're not journaling, but we still need to
* call into ext4_journal_revoke() to put the buffer head.
*/
int __ext4_forget(const char *where, unsigned int line, handle_t *handle,
int is_metadata, struct inode *inode,
struct buffer_head *bh, ext4_fsblk_t blocknr)
{
int err;
might_sleep();
trace_ext4_forget(inode, is_metadata, blocknr);
BUFFER_TRACE(bh, "enter");
jbd_debug(4, "forgetting bh %p: is_metadata = %d, mode %o, "
"data mode %x\n",
bh, is_metadata, inode->i_mode,
test_opt(inode->i_sb, DATA_FLAGS));
/* In the no journal case, we can just do a bforget and return */
if (!ext4_handle_valid(handle)) {
bforget(bh);
return 0;
}
/* Never use the revoke function if we are doing full data
* journaling: there is no need to, and a V1 superblock won't
* support it. Otherwise, only skip the revoke on un-journaled
* data blocks. */
if (test_opt(inode->i_sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA ||
(!is_metadata && !ext4_should_journal_data(inode))) {
if (bh) {
BUFFER_TRACE(bh, "call jbd2_journal_forget");
err = jbd2_journal_forget(handle, bh);
if (err)
ext4_journal_abort_handle(where, line, __func__,
bh, handle, err);
return err;
}
return 0;
}
/*
* data!=journal && (is_metadata || should_journal_data(inode))
*/
BUFFER_TRACE(bh, "call jbd2_journal_revoke");
err = jbd2_journal_revoke(handle, blocknr, bh);
if (err) {
ext4_journal_abort_handle(where, line, __func__,
bh, handle, err);
__ext4_abort(inode->i_sb, where, line,
"error %d when attempting revoke", err);
}
BUFFER_TRACE(bh, "exit");
return err;
}
int __ext4_journal_get_create_access(const char *where, unsigned int line,
handle_t *handle, struct buffer_head *bh)
{
int err = 0;
if (ext4_handle_valid(handle)) {
err = jbd2_journal_get_create_access(handle, bh);
if (err)
ext4_journal_abort_handle(where, line, __func__,
bh, handle, err);
}
return err;
}
int __ext4_handle_dirty_metadata(const char *where, unsigned int line,
handle_t *handle, struct inode *inode,
struct buffer_head *bh)
{
int err = 0;
might_sleep();
set_buffer_meta(bh);
set_buffer_prio(bh);
if (ext4_handle_valid(handle)) {
err = jbd2_journal_dirty_metadata(handle, bh);
/* Errors can only happen due to aborted journal or a nasty bug */
if (!is_handle_aborted(handle) && WARN_ON_ONCE(err)) {
ext4_journal_abort_handle(where, line, __func__, bh,
handle, err);
if (inode == NULL) {
pr_err("EXT4: jbd2_journal_dirty_metadata "
"failed: handle type %u started at "
"line %u, credits %u/%u, errcode %d",
handle->h_type,
handle->h_line_no,
handle->h_requested_credits,
handle->h_buffer_credits, err);
return err;
}
ext4_error_inode(inode, where, line,
bh->b_blocknr,
"journal_dirty_metadata failed: "
"handle type %u started at line %u, "
"credits %u/%u, errcode %d",
handle->h_type,
handle->h_line_no,
handle->h_requested_credits,
handle->h_buffer_credits, err);
}
} else {
if (inode)
mark_buffer_dirty_inode(bh, inode);
else
mark_buffer_dirty(bh);
if (inode && inode_needs_sync(inode)) {
sync_dirty_buffer(bh);
if (buffer_req(bh) && !buffer_uptodate(bh)) {
struct ext4_super_block *es;
es = EXT4_SB(inode->i_sb)->s_es;
es->s_last_error_block =
cpu_to_le64(bh->b_blocknr);
ext4_error_inode(inode, where, line,
bh->b_blocknr,
"IO error syncing itable block");
err = -EIO;
}
}
}
return err;
}
int __ext4_handle_dirty_super(const char *where, unsigned int line,
handle_t *handle, struct super_block *sb)
{
struct buffer_head *bh = EXT4_SB(sb)->s_sbh;
int err = 0;
ext4_superblock_csum_set(sb);
if (ext4_handle_valid(handle)) {
err = jbd2_journal_dirty_metadata(handle, bh);
if (err)
ext4_journal_abort_handle(where, line, __func__,
bh, handle, err);
} else
mark_buffer_dirty(bh);
return err;
}