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authorAlexander Lochmann <alexander.lochmann@tu-dortmund.de>2021-02-11 10:51:55 +0100
committerTheodore Ts'o <tytso@mit.edu>2021-04-02 11:37:58 -0400
commitd699ae4fc27496d01e8bc5ab2106bd79d1e7be92 (patch)
treeb101b797e7a5a68c7dcdcc0fc865b169001d29bc /include/linux/jbd2.h
parentbd256fda92efe97b692dc72e246d35fa724d42d8 (diff)
ext4: updated locking documentation for journal_t
Some members of transaction_t are allowed to be read without any lock being held if consistency doesn't matter. Based on LockDoc's findings, we extended the locking documentation of those members. Each one of them is marked with a short comment: "no lock for quick racy checks". Signed-off-by: Alexander Lochmann <alexander.lochmann@tu-dortmund.de> Signed-off-by: Horst Schirmeier <horst.schirmeier@tu-dortmund.de> Reviewed-by: Jan Kara <jack@suse.cz> Link: https://lore.kernel.org/r/ad82c7a9-a624-4ed5-5ada-a6410c44c0b3@tu-dortmund.de Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Diffstat (limited to 'include/linux/jbd2.h')
-rw-r--r--include/linux/jbd2.h13
1 files changed, 8 insertions, 5 deletions
diff --git a/include/linux/jbd2.h b/include/linux/jbd2.h
index 99d3cd051ac3..74710bb231a6 100644
--- a/include/linux/jbd2.h
+++ b/include/linux/jbd2.h
@@ -768,7 +768,8 @@ enum passtype {PASS_SCAN, PASS_REVOKE, PASS_REPLAY};
struct journal_s
{
/**
- * @j_flags: General journaling state flags [j_state_lock]
+ * @j_flags: General journaling state flags [j_state_lock,
+ * no lock for quick racy checks]
*/
unsigned long j_flags;
@@ -808,7 +809,8 @@ struct journal_s
/**
* @j_barrier_count:
*
- * Number of processes waiting to create a barrier lock [j_state_lock]
+ * Number of processes waiting to create a barrier lock [j_state_lock,
+ * no lock for quick racy checks]
*/
int j_barrier_count;
@@ -821,7 +823,8 @@ struct journal_s
* @j_running_transaction:
*
* Transactions: The current running transaction...
- * [j_state_lock] [caller holding open handle]
+ * [j_state_lock, no lock for quick racy checks] [caller holding
+ * open handle]
*/
transaction_t *j_running_transaction;
@@ -1033,7 +1036,7 @@ struct journal_s
* @j_commit_sequence:
*
* Sequence number of the most recently committed transaction
- * [j_state_lock].
+ * [j_state_lock, no lock for quick racy checks]
*/
tid_t j_commit_sequence;
@@ -1041,7 +1044,7 @@ struct journal_s
* @j_commit_request:
*
* Sequence number of the most recent transaction wanting commit
- * [j_state_lock]
+ * [j_state_lock, no lock for quick racy checks]
*/
tid_t j_commit_request;