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Commit 1ba37268 authored by Yongqiang Yang's avatar Yongqiang Yang Committed by Theodore Ts'o
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jbd2: clear revoked flag on buffers before a new transaction started 



Currently, we clear revoked flag only when a block is reused.  However,
this can tigger a false journal error.  Consider a situation when a block
is used as a meta block and is deleted(revoked) in ordered mode, then the
block is allocated as a data block to a file.  At this moment, user changes
the file's journal mode from ordered to journaled and truncates the file.
The block will be considered re-revoked by journal because it has revoked
flag still pending from the last transaction and an assertion triggers.

We fix the problem by keeping the revoked status more uptodate - we clear
revoked flag when switching revoke tables to reflect there is no revoked
buffers in current transaction any more.

Signed-off-by: default avatarYongqiang Yang <xiaoqiangnk@gmail.com>
Signed-off-by: default avatar"Theodore Ts'o" <tytso@mit.edu>
parent 5872ddaa

fs/jbd2/commit.c

+6 −0
Original line number Diff line number Diff line
@@ -429,6 +429,12 @@ void jbd2_journal_commit_transaction(journal_t *journal) 


	jbd_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.

	 */

fs/jbd2/revoke.c

+34 −0
Original line number Diff line number Diff line
@@ -47,6 +47,10 @@ 
 *   overwriting the new data.  We don't even need to clear the revoke

 *   bit here.

 *

 * We cache revoke status of a buffer in the current transaction in b_states

 * bits.  As the name says, revokevalid flag indicates that the cached revoke

 * status of a buffer is valid and we can rely on the cached status.

 *

 * Revoke information on buffers is a tri-state value:

 *

 * RevokeValid clear:	no cached revoke status, need to look it up
@@ -478,6 +482,36 @@ int jbd2_journal_cancel_revoke(handle_t *handle, struct journal_head *jh) 
	return did_revoke;

}



/*

 * journal_clear_revoked_flag clears revoked flag of buffers in

 * revoke table to reflect there is no revoked buffers in the next

 * transaction which is going to be started.

 */

void jbd2_clear_buffer_revoked_flags(journal_t *journal)

{

	struct jbd2_revoke_table_s *revoke = journal->j_revoke;

	int i = 0;



	for (i = 0; i < revoke->hash_size; i++) {

		struct list_head *hash_list;

		struct list_head *list_entry;

		hash_list = &revoke->hash_table[i];



		list_for_each(list_entry, hash_list) {

			struct jbd2_revoke_record_s *record;

			struct buffer_head *bh;

			record = (struct jbd2_revoke_record_s *)list_entry;

			bh = __find_get_block(journal->j_fs_dev,

					      record->blocknr,

					      journal->j_blocksize);

			if (bh) {

				clear_buffer_revoked(bh);

				__brelse(bh);

			}

		}

	}

}



/* journal_switch_revoke table select j_revoke for next transaction

 * we do not want to suspend any processing until all revokes are

 * written -bzzz

include/linux/jbd2.h

+1 −0
Original line number Diff line number Diff line
@@ -1151,6 +1151,7 @@ extern int jbd2_journal_set_revoke(journal_t *, unsigned long long, tid_t); 
extern int	jbd2_journal_test_revoke(journal_t *, unsigned long long, tid_t);

extern void	jbd2_journal_clear_revoke(journal_t *);

extern void	jbd2_journal_switch_revoke_table(journal_t *journal);

extern void	jbd2_clear_buffer_revoked_flags(journal_t *journal);



/*

 * The log thread user interface: