From 62dd0f98a0e5668424270b47a0c2e973795faba7 Mon Sep 17 00:00:00 2001 From: Andrew Price Date: Mon, 15 Mar 2021 12:24:00 +0000 Subject: gfs2: Flag a withdraw if init_threads() fails Interrupting mount with ^C quickly enough can cause the kthread_run() calls in gfs2's init_threads() to fail and the error path leads to a deadlock on the s_umount rwsem. The abridged chain of events is: [mount path] get_tree_bdev() sget_fc() alloc_super() down_write_nested(&s->s_umount, SINGLE_DEPTH_NESTING); [acquired] gfs2_fill_super() gfs2_make_fs_rw() init_threads() kthread_run() ( Interrupted ) [Error path] gfs2_gl_hash_clear() flush_workqueue(glock_workqueue) wait_for_completion() [workqueue context] glock_work_func() run_queue() do_xmote() freeze_go_sync() freeze_super() down_write(&sb->s_umount) [deadlock] In freeze_go_sync() there is a gfs2_withdrawn() check that we can use to make sure freeze_super() is not called in the error path, so add a gfs2_withdraw_delayed() call when init_threads() fails. Ref: https://bugzilla.kernel.org/show_bug.cgi?id=212231 Reported-by: Alexander Aring Signed-off-by: Andrew Price Signed-off-by: Andreas Gruenbacher --- fs/gfs2/super.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'fs/gfs2') diff --git a/fs/gfs2/super.c b/fs/gfs2/super.c index 97076d3f562f..9e91c9d92bd6 100644 --- a/fs/gfs2/super.c +++ b/fs/gfs2/super.c @@ -162,8 +162,10 @@ int gfs2_make_fs_rw(struct gfs2_sbd *sdp) int error; error = init_threads(sdp); - if (error) + if (error) { + gfs2_withdraw_delayed(sdp); return error; + } j_gl->gl_ops->go_inval(j_gl, DIO_METADATA); if (gfs2_withdrawn(sdp)) { -- cgit v1.2.3 From ff132c5f93c06bd4432bbab5c369e468653bdec4 Mon Sep 17 00:00:00 2001 From: Bob Peterson Date: Thu, 25 Mar 2021 08:51:13 -0400 Subject: gfs2: report "already frozen/thawed" errors Before this patch, gfs2's freeze function failed to report an error when the target file system was already frozen as it should (and as generic vfs function freeze_super does. Similarly, gfs2's thaw function failed to report an error when trying to thaw a file system that is not frozen, as vfs function thaw_super does. The errors were checked, but it always returned a 0 return code. This patch adds the missing error return codes to gfs2 freeze and thaw. Signed-off-by: Bob Peterson Signed-off-by: Andreas Gruenbacher --- fs/gfs2/super.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) (limited to 'fs/gfs2') diff --git a/fs/gfs2/super.c b/fs/gfs2/super.c index 9e91c9d92bd6..8fb9602d79b4 100644 --- a/fs/gfs2/super.c +++ b/fs/gfs2/super.c @@ -752,11 +752,13 @@ void gfs2_freeze_func(struct work_struct *work) static int gfs2_freeze(struct super_block *sb) { struct gfs2_sbd *sdp = sb->s_fs_info; - int error = 0; + int error; mutex_lock(&sdp->sd_freeze_mutex); - if (atomic_read(&sdp->sd_freeze_state) != SFS_UNFROZEN) + if (atomic_read(&sdp->sd_freeze_state) != SFS_UNFROZEN) { + error = -EBUSY; goto out; + } for (;;) { if (gfs2_withdrawn(sdp)) { @@ -797,10 +799,10 @@ static int gfs2_unfreeze(struct super_block *sb) struct gfs2_sbd *sdp = sb->s_fs_info; mutex_lock(&sdp->sd_freeze_mutex); - if (atomic_read(&sdp->sd_freeze_state) != SFS_FROZEN || + if (atomic_read(&sdp->sd_freeze_state) != SFS_FROZEN || !gfs2_holder_initialized(&sdp->sd_freeze_gh)) { mutex_unlock(&sdp->sd_freeze_mutex); - return 0; + return -EINVAL; } gfs2_freeze_unlock(&sdp->sd_freeze_gh); -- cgit v1.2.3