Commit 5b3a9f34 authored Apr 26, 2019 by Bob Peterson Committed by Andreas Gruenbacher Jun 27, 2019

gfs2: kthread and remount improvements



Before this patch, gfs2 saved the pointers to the two daemon threads
(logd and quotad) in the superblock, but they were never cleared,
even if the threads were stopped (e.g. on remount -o ro). That meant
that certain error conditions (like a withdrawn file system) could
race. For example, xfstests generic/361 caused an IO error during
remount -o ro, which caused the kthreads to be stopped, then the
error flagged. Later, when the test unmounted the file system, it
would try to stop the threads a second time with kthread_stop.

This patch does two things: First, every time it stops the threads
it zeroes out the thread pointer, and also checks whether it's NULL
before trying to stop it. Second, in function gfs2_remount_fs, it
was returning if an error was logged by either of the two functions
for gfs2_make_fs_ro and _rw, which caused it to bypass the online
uevent at the bottom of the function. This removes that bypass in
favor of just running the whole function, then returning the error.
That way, unmounts and remounts won't hang forever.

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>

parent 15a798f7

fs/gfs2/super.c

+14 −7

Original line number	Diff line number	Diff line
		@@ -394,6 +394,7 @@ static int init_threads(struct gfs2_sbd *sdp)

		fail:
		kthread_stop(sdp->sd_logd_process);
		sdp->sd_logd_process = NULL;
		return error;
		}

		@@ -451,8 +452,12 @@ fail:
		freeze_gh.gh_flags \|= GL_NOCACHE;
		gfs2_glock_dq_uninit(&freeze_gh);
		fail_threads:
		if (sdp->sd_quotad_process)
		kthread_stop(sdp->sd_quotad_process);
		sdp->sd_quotad_process = NULL;
		if (sdp->sd_logd_process)
		kthread_stop(sdp->sd_logd_process);
		sdp->sd_logd_process = NULL;
		return error;
		}

		@@ -853,8 +858,12 @@ static int gfs2_make_fs_ro(struct gfs2_sbd *sdp)
		return error;

		flush_workqueue(gfs2_delete_workqueue);
		if (sdp->sd_quotad_process)
		kthread_stop(sdp->sd_quotad_process);
		sdp->sd_quotad_process = NULL;
		if (sdp->sd_logd_process)
		kthread_stop(sdp->sd_logd_process);
		sdp->sd_logd_process = NULL;

		gfs2_quota_sync(sdp->sd_vfs, 0);
		gfs2_statfs_sync(sdp->sd_vfs, 0);
		@@ -1273,8 +1282,6 @@ static int gfs2_remount_fs(struct super_block sb, int flags, char *data)
		error = gfs2_make_fs_ro(sdp);
		else
		error = gfs2_make_fs_rw(sdp);
		if (error)
		return error;
		}

		sdp->sd_args = args;
		@@ -1300,7 +1307,7 @@ static int gfs2_remount_fs(struct super_block sb, int flags, char *data)
		spin_unlock(&gt->gt_spin);

		gfs2_online_uevent(sdp);
		return 0;
		return error;
		}

		/**

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