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jbd2: move escape handle to futher improve jbd2_journal_write_metadata_buffer 

Move escape handle to futher improve code readability and remove some
repeat check.

Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Zhang Yi <yi.zhang@huawei.com>
Link: https://patch.msgid.link/20240801013815.2393869-7-shikemeng@huaweicloud.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
pull/959/head
Kemeng Shi 2024-08-01 09:38:13 +08:00 committed by Theodore Ts'o
parent 7c48e7d5a1
commit f47aa3ebe3
1 changed files with 24 additions and 25 deletions
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49
fs/jbd2/journal.c
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@ -281,6 +281,16 @@ static void journal_kill_thread(journal_t *journal)
write_unlock(&journal->j_state_lock);
}
static inline bool jbd2_data_needs_escaping(char *data)
{
return *((__be32 *)data) == cpu_to_be32(JBD2_MAGIC_NUMBER);
}
static inline void jbd2_data_do_escape(char *data)
{
*((unsigned int *)data) = 0;
}
/*
* jbd2_journal_write_metadata_buffer: write a metadata buffer to the journal.
*
@ -319,7 +329,6 @@ int jbd2_journal_write_metadata_buffer(transaction_t *transaction,
sector_t blocknr)
{
int do_escape = 0;
char *mapped_data;
struct buffer_head *new_bh;
struct folio *new_folio;
unsigned int new_offset;
@ -350,8 +359,13 @@ int jbd2_journal_write_metadata_buffer(transaction_t *transaction,
if (jh_in->b_frozen_data) {
new_folio = virt_to_folio(jh_in->b_frozen_data);
new_offset = offset_in_folio(new_folio, jh_in->b_frozen_data);
mapped_data = jh_in->b_frozen_data;
do_escape = jbd2_data_needs_escaping(jh_in->b_frozen_data);
if (do_escape)
jbd2_data_do_escape(jh_in->b_frozen_data);
} else {
char *tmp;
char *mapped_data;
new_folio = bh_in->b_folio;
new_offset = offset_in_folio(new_folio, bh_in->b_data);
mapped_data = kmap_local_folio(new_folio, new_offset);
@ -363,21 +377,13 @@ int jbd2_journal_write_metadata_buffer(transaction_t *transaction,
*/
jbd2_buffer_frozen_trigger(jh_in, mapped_data,
jh_in->b_triggers);
}
/*
* Check for escaping
*/
if (*((__be32 *)mapped_data) == cpu_to_be32(JBD2_MAGIC_NUMBER))
do_escape = 1;
if (!jh_in->b_frozen_data)
do_escape = jbd2_data_needs_escaping(mapped_data);
kunmap_local(mapped_data);
/*
* Do we need to do a data copy?
*/
if (do_escape && !jh_in->b_frozen_data) {
char *tmp;
/*
* Do we need to do a data copy?
*/
if (!do_escape)
goto escape_done;
spin_unlock(&jh_in->b_state_lock);
tmp = jbd2_alloc(bh_in->b_size, GFP_NOFS);
@ -404,17 +410,10 @@ int jbd2_journal_write_metadata_buffer(transaction_t *transaction,
copy_done:
new_folio = virt_to_folio(jh_in->b_frozen_data);
new_offset = offset_in_folio(new_folio, jh_in->b_frozen_data);
jbd2_data_do_escape(jh_in->b_frozen_data);
}
/*
* Did we need to do an escaping? Now we've done all the
* copying, we can finally do so.
* b_frozen_data is from jbd2_alloc() which always provides an
* address from the direct kernels mapping.
*/
if (do_escape)
*((unsigned int *)jh_in->b_frozen_data) = 0;
escape_done:
folio_set_bh(new_bh, new_folio, new_offset);
new_bh->b_size = bh_in->b_size;
new_bh->b_bdev = journal->j_dev;