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: Yongqiang Yang <xiaoqiangnk@xxxxxxxxx>
---
fs/jbd/commit.c | 6 ++++++
fs/jbd/revoke.c | 34 ++++++++++++++++++++++++++++++++++
include/linux/jbd.h | 1 +
3 files changed, 41 insertions(+), 0 deletions(-)
diff --git a/fs/jbd/commit.c b/fs/jbd/commit.c
index 8799207..f2b9a57 100644
--- a/fs/jbd/commit.c
+++ b/fs/jbd/commit.c
@@ -392,6 +392,12 @@ void journal_commit_transaction(journal_t *journal)
jbd_debug (3, "JBD: commit phase 1\n");
/*
+ * Clear revoked flag to reflect there is no revoked buffers
+ * in the next transaction which is going to be started.
+ */
+ journal_clear_buffer_revoked_flags(journal);
+
+ /*
* Switch to a new revoke table.
*/
journal_switch_revoke_table(journal);
diff --git a/fs/jbd/revoke.c b/fs/jbd/revoke.c
index 034eb82..501d363 100644
--- a/fs/jbd/revoke.c
+++ b/fs/jbd/revoke.c
@@ -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
@@ -474,6 +478,36 @@ int 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 journal_clear_buffer_revoked_flags(journal_t *journal)
+{
+ struct jbd_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 jbd_revoke_record_s *record;
+ struct buffer_head *bh;
+ record = (struct jbd_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
diff --git a/include/linux/jbd.h b/include/linux/jbd.h
index 0f9f0b6..5aa964e 100644
--- a/include/linux/jbd.h
+++ b/include/linux/jbd.h
@@ -918,6 +918,7 @@ extern int journal_set_revoke(journal_t *, unsigned int, tid_t);
extern int journal_test_revoke(journal_t *, unsigned int, tid_t);
extern void journal_clear_revoke(journal_t *);
extern void journal_switch_revoke_table(journal_t *journal);
+extern void journal_clear_buffer_revoked_flags(journal_t *journal);
/*
* The log thread user interface:
--
1.7.5.1
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