While testing and rearranging pquota/gquota code, I stumbled
on a xfs_shutdown() during a mount. But the mount just hung.
Debugged and found that there is a deadlock involving
&log->l_cilp->xc_ctx_lock.
It is in a code path where &log->l_cilp->xc_ctx_lock is first
acquired in read mode and some levels down the same semaphore
is being acquired in write mode causing a deadlock.
This is the stack:
xfs_log_commit_cil -> acquires &log->l_cilp->xc_ctx_lock in read mode
xlog_print_tic_res
xfs_force_shutdown
xfs_log_force_umount
xlog_cil_force
xlog_cil_force_lsn
xlog_cil_push_foreground
xlog_cil_push - tries to acquire same semaphore in write mode
This patch fixes the deadlock by changing the reason code for
xfs_force_shutdown in xlog_print_tic_res() to SHUTDOWN_LOG_IO_ERROR.
SHUTDOWN_LOG_IO_ERROR is the right reason code to be set since
we are in the log path.
Thanks to Dave for suggesting this solution.
Signed-off-by: Chandra Seetharaman <sekharan@xxxxxxxxxx>
---
fs/xfs/xfs_log.c | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)
diff --git a/fs/xfs/xfs_log.c b/fs/xfs/xfs_log.c
index d852a2b..bf89eb9 100644
--- a/fs/xfs/xfs_log.c
+++ b/fs/xfs/xfs_log.c
@@ -1941,7 +1941,7 @@ xlog_print_tic_res(
xfs_alert_tag(mp, XFS_PTAG_LOGRES,
"xlog_write: reservation ran out. Need to up reservation");
- xfs_force_shutdown(mp, SHUTDOWN_CORRUPT_INCORE);
+ xfs_force_shutdown(mp, SHUTDOWN_LOG_IO_ERROR);
}
/*
--
1.7.1
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