From: Dave Chinner Date: Wed, 14 Apr 2010 05:47:55 +0000 (+1000) Subject: xfs: make the log ticket transaction id random X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=f983710758218c7aad4aae3e40a7312a21d6f55a;p=GitHub%2Fmt8127%2Fandroid_kernel_alcatel_ttab.git xfs: make the log ticket transaction id random The transaction ID that is written to the log for a transaction is currently set by taking the lower 32 bits of the memory address of the ticket structure. This is not guaranteed to be unique as tickets comes from a slab and slots can be reallocated immediately after being freed. As a result, there is no guarantee of uniqueness in the ticket ID value. Fix this by assigning a random number to the ticket ID field so that it is extremely unlikely that duplicates will occur and remove the possibility of transactions being mixed up during recovery due to duplicate IDs. Signed-off-by: Dave Chinner Reviewed-by: Christoph Hellwig --- diff --git a/fs/xfs/xfs_log.c b/fs/xfs/xfs_log.c index 9edbd67b5a9d..77593c2ead4d 100644 --- a/fs/xfs/xfs_log.c +++ b/fs/xfs/xfs_log.c @@ -3417,7 +3417,7 @@ xlog_ticket_alloc( tic->t_curr_res = unit_bytes; tic->t_cnt = cnt; tic->t_ocnt = cnt; - tic->t_tid = (xlog_tid_t)((__psint_t)tic & 0xffffffff); + tic->t_tid = random32(); tic->t_clientid = client; tic->t_flags = XLOG_TIC_INITED; tic->t_trans_type = 0;