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* [PATCH 1/2] libblkid: Don't check BLKID_PROBE_INTERVAL in blkid_verify
@ 2019-05-13 12:32 Nikolay Borisov
  2019-05-13 12:32 ` [PATCH 2/2] libblkid: Set BLKID_BID_FL_VERIFIED in case revalidation is not needed Nikolay Borisov
  0 siblings, 1 reply; 2+ messages in thread
From: Nikolay Borisov @ 2019-05-13 12:32 UTC (permalink / raw)
  To: kzak; +Cc: util-linux, Nikolay Borisov

That constant is set to 200 seconds and is already check in probe_all().
It essentially controls how often blkid_probe_all can do a full cache
revalidation. Since blkid_verify is called from within probe_all() iff at least 
BLKID_PROBE_INTERVAL seconds have elapsed it makes no sense to check this value 
in blkid_verify. 

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
---
 libblkid/src/verify.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/libblkid/src/verify.c b/libblkid/src/verify.c
index 7f44f5497c8e..49fc11d228b8 100644
--- a/libblkid/src/verify.c
+++ b/libblkid/src/verify.c
@@ -96,8 +96,7 @@ blkid_dev blkid_verify(blkid_cache cache, blkid_dev dev)
 	    st.st_mtime <= dev->bid_time &&
 #endif
 	    (diff < BLKID_PROBE_MIN ||
-		(dev->bid_flags & BLKID_BID_FL_VERIFIED &&
-		 diff < BLKID_PROBE_INTERVAL)))
+		dev->bid_flags & BLKID_BID_FL_VERIFIED)) {
 		return dev;
 
 #ifndef HAVE_STRUCT_STAT_ST_MTIM_TV_NSEC
-- 
2.7.4


^ permalink raw reply	[flat|nested] 2+ messages in thread

* [PATCH 2/2] libblkid: Set BLKID_BID_FL_VERIFIED in case revalidation is not needed
  2019-05-13 12:32 [PATCH 1/2] libblkid: Don't check BLKID_PROBE_INTERVAL in blkid_verify Nikolay Borisov
@ 2019-05-13 12:32 ` Nikolay Borisov
  0 siblings, 0 replies; 2+ messages in thread
From: Nikolay Borisov @ 2019-05-13 12:32 UTC (permalink / raw)
  To: kzak; +Cc: util-linux, Nikolay Borisov

If blkid_verify deems that device revalidation is not needed since BLKID_PROBE_MIN
seconds haven't elapsed since the last revalidation of the device it returns
a blkid_dev. However, if this device has been read from the cache file on disk then 
it wont' have BLKID_BID_FL_VERIFIED bit set. This in turn could lead to a later 
call to blkid_dev_get free this device in case its part of a multi device
configuration. This is particularly relevant to btrfs raid configurations. 

Namely this  was exhibited by btrfs-progs which use blkid for device enumeration.
In case of a multi-device filesystem (i.e raid10) running xfstest btrfs/011
would fail sporadically since cached devices read from cache were not revalidated
due to being recently validated (according to timestamp in the cache file) at 
the same time their in-memory blkid_dev structures didn't have BLKID_BID_FL_VERIFIED
set. This lead to their untimely removal from the cache from blkid_get_dev. 

Fix this by setting the BLKID_BID_FL_VERIFIED when returning from blkid_verify
with a valid device irrespective of whether full revalidation was performed or 
the device is deemed valid due to being recently validated. 

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
---
 libblkid/src/verify.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/libblkid/src/verify.c b/libblkid/src/verify.c
index 49fc11d228b8..58b347751e73 100644
--- a/libblkid/src/verify.c
+++ b/libblkid/src/verify.c
@@ -97,7 +97,9 @@ blkid_dev blkid_verify(blkid_cache cache, blkid_dev dev)
 #endif
 	    (diff < BLKID_PROBE_MIN ||
 		dev->bid_flags & BLKID_BID_FL_VERIFIED)) {
+		dev->bid_flags |= BLKID_BID_FL_VERIFIED;
 		return dev;
+	}
 
 #ifndef HAVE_STRUCT_STAT_ST_MTIM_TV_NSEC
 	DBG(PROBE, ul_debug("need to revalidate %s (cache time %lu, stat time %lu,\t"
-- 
2.7.4


^ permalink raw reply	[flat|nested] 2+ messages in thread

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2019-05-13 12:32 [PATCH 1/2] libblkid: Don't check BLKID_PROBE_INTERVAL in blkid_verify Nikolay Borisov
2019-05-13 12:32 ` [PATCH 2/2] libblkid: Set BLKID_BID_FL_VERIFIED in case revalidation is not needed Nikolay Borisov

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