iv/linux
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Updated locking documentation for transaction_t

Browse Source 
Some members of transaction_t are allowed to be read without any lock
being held if accessed from the correct context.  We used LockDoc's
findings to determine those members.  Each member of them is marked
with a short comment: "no lock needed for jbd2 thread".

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/20210211171410.17984-1-alexander.lochmann@tu-dortmund.de
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
This commit is contained in:
Alexander Lochmann 2021-02-11 18:14:10 +01:00 committed by Theodore Ts'o
parent d699ae4fc2
commit 3042b1b45c
1 changed files with 12 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

18
include/linux/jbd2.h
View File

@ -594,18 +594,22 @@ struct transaction_s
*/
unsigned long t_log_start;
/* Number of buffers on the t_buffers list [j_list_lock] */
/*
* Number of buffers on the t_buffers list [j_list_lock, no locks
* needed for jbd2 thread]
*/
int t_nr_buffers;
/*
* Doubly-linked circular list of all buffers reserved but not yet
* modified by this transaction [j_list_lock]
* modified by this transaction [j_list_lock, no locks needed fo
* jbd2 thread]
*/
struct journal_head *t_reserved_list;
/*
* Doubly-linked circular list of all metadata buffers owned by this
* transaction [j_list_lock]
* transaction [j_list_lock, no locks needed for jbd2 thread]
*/
struct journal_head *t_buffers;
@ -629,9 +633,11 @@ struct transaction_s
struct journal_head *t_checkpoint_io_list;
/*
* Doubly-linked circular list of metadata buffers being shadowed by log
* IO. The IO buffers on the iobuf list and the shadow buffers on this
* list match each other one for one at all times. [j_list_lock]
* Doubly-linked circular list of metadata buffers being
* shadowed by log IO. The IO buffers on the iobuf list and
* the shadow buffers on this list match each other one for
* one at all times. [j_list_lock, no locks needed for jbd2
* thread]
*/
struct journal_head *t_shadow_list;