From: Dave Chinner dchinner@redhat.com
mainline-inclusion from mainline-v5.13-rc4 commit b6903358c230c517b29ecdb6123276d96cc0beab category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I4KIAO CVE: NA
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...
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If we are processing callbacks on an iclog, nothing can be concurrently adding callbacks to the loop. We only add callbacks to the iclog when they are in ACTIVE or WANT_SYNC state, and we explicitly do not add callbacks if the iclog is already in IOERROR state.
The only way to have a dequeue racing with an enqueue is to be processing a shutdown without a direct reference to an iclog in ACTIVE or WANT_SYNC state. As the enqueue avoids this race condition, we only ever need a single dequeue operation in xlog_state_do_iclog_callbacks(). Hence we can remove the loop.
Signed-off-by: Dave Chinner dchinner@redhat.com Reviewed-by: Brian Foster bfoster@redhat.com Reviewed-by: Darrick J. Wong djwong@kernel.org Signed-off-by: Darrick J. Wong djwong@kernel.org Signed-off-by: Guo Xuenan guoxuenan@huawei.com Reviewed-by: Lihong Kou koulihong@huawei.com Reviewed-by: Zhang Yi yi.zhang@huawei.com Signed-off-by: Zheng Zengkai zhengzengkai@huawei.com --- fs/xfs/xfs_log.c | 14 ++++---------- 1 file changed, 4 insertions(+), 10 deletions(-)
diff --git a/fs/xfs/xfs_log.c b/fs/xfs/xfs_log.c index 26ace6c12e3a..a68fdae831af 100644 --- a/fs/xfs/xfs_log.c +++ b/fs/xfs/xfs_log.c @@ -2688,19 +2688,13 @@ xlog_state_do_iclog_callbacks( struct xlog *log, struct xlog_in_core *iclog) { - spin_lock(&iclog->ic_callback_lock); - - while (!list_empty(&iclog->ic_callbacks)) { - LIST_HEAD(tmp);
- list_splice_init(&iclog->ic_callbacks, &tmp); - - spin_unlock(&iclog->ic_callback_lock); - xlog_cil_process_committed(&tmp); - spin_lock(&iclog->ic_callback_lock); - } + LIST_HEAD(tmp);
+ spin_lock(&iclog->ic_callback_lock); + list_splice_init(&iclog->ic_callbacks, &tmp); spin_unlock(&iclog->ic_callback_lock); + xlog_cil_process_committed(&tmp); }
STATIC void