[Cluster-devel] [PATCH] gfs2: fix race between gfs2_freeze_func and unmount
Abhi Das
adas at redhat.com
Tue Apr 30 17:48:30 UTC 2019
gfs2_unfreee() doesn't wait for gfs2_freeze_func() to complete. If a
umount is issued right after unfreeze, it could result in an
inconsistent filesystem because some journal data (statfs update)
wasn't written out.
This patch causes gfs2_unfreeze() to wait for gfs2_freeze_func() to
complete before returning to the user.
Signed-off-by: Abhi Das <adas at redhat.com>
---
fs/gfs2/incore.h | 1 +
fs/gfs2/super.c | 8 +++++---
2 files changed, 6 insertions(+), 3 deletions(-)
diff --git a/fs/gfs2/incore.h b/fs/gfs2/incore.h
index 78c8e761b321..b15755068593 100644
--- a/fs/gfs2/incore.h
+++ b/fs/gfs2/incore.h
@@ -621,6 +621,7 @@ enum {
SDF_SKIP_DLM_UNLOCK = 8,
SDF_FORCE_AIL_FLUSH = 9,
SDF_AIL1_IO_ERROR = 10,
+ SDF_FS_FROZEN = 11,
};
enum gfs2_freeze_state {
diff --git a/fs/gfs2/super.c b/fs/gfs2/super.c
index a6a325b2a78b..a81d7a5afe39 100644
--- a/fs/gfs2/super.c
+++ b/fs/gfs2/super.c
@@ -973,8 +973,7 @@ void gfs2_freeze_func(struct work_struct *work)
if (error) {
printk(KERN_INFO "GFS2: couldn't get freeze lock : %d\n", error);
gfs2_assert_withdraw(sdp, 0);
- }
- else {
+ } else {
atomic_set(&sdp->sd_freeze_state, SFS_UNFROZEN);
error = thaw_super(sb);
if (error) {
@@ -987,6 +986,8 @@ void gfs2_freeze_func(struct work_struct *work)
gfs2_glock_dq_uninit(&freeze_gh);
}
deactivate_super(sb);
+ clear_bit(SDF_FS_FROZEN, &sdp->sd_flags);
+ wake_up_bit(&sdp->sd_flags, SDF_FS_FROZEN);
return;
}
@@ -1029,6 +1030,7 @@ static int gfs2_freeze(struct super_block *sb)
msleep(1000);
}
error = 0;
+ set_bit(SDF_FS_FROZEN, &sdp->sd_flags);
out:
mutex_unlock(&sdp->sd_freeze_mutex);
return error;
@@ -1053,7 +1055,7 @@ static int gfs2_unfreeze(struct super_block *sb)
gfs2_glock_dq_uninit(&sdp->sd_freeze_gh);
mutex_unlock(&sdp->sd_freeze_mutex);
- return 0;
+ return wait_on_bit(&sdp->sd_flags, SDF_FS_FROZEN, TASK_INTERRUPTIBLE);
}
/**
--
2.20.1
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