From mboxrd@z Thu Jan 1 00:00:00 1970 From: NeilBrown Subject: Re: [BUG] MD/RAID1 hung forever on freeze_array Date: Fri, 09 Dec 2016 17:01:51 +1100 Message-ID: <87inqt1vzk.fsf@notabene.neil.brown.name> References: <519e773d-e6e6-5d79-7224-ef94ef7c7a93@suse.de> <871sxj2jpd.fsf@notabene.neil.brown.name> Mime-Version: 1.0 Content-Type: multipart/signed; boundary="=-=-="; micalg=pgp-sha256; protocol="application/pgp-signature" Return-path: In-Reply-To: Sender: linux-raid-owner@vger.kernel.org To: Jinpu Wang Cc: Coly Li , linux-raid@vger.kernel.org, Shaohua Li , Nate Dailey List-Id: linux-raid.ids --=-=-= Content-Type: text/plain On Thu, Dec 08 2016, Jinpu Wang wrote: This number: > nr_pending = { > counter = 1 > }, and this number: > nr_pending = { > counter = 856 > }, might be interesting. There are 855 requested on the list. Add the one that is currently being retried give 856, which is nr_pending for the device that failed. But nr_pending on the device that didn't fail is 1. I would expect zero. When a read or write requests succeeds, rdev_dec_pending() is called immediately so this should quickly go to zero. It seems as though there must be a request to the loop device that is stuck somewhere between the atomic_inc(&rdev->nr_pending) (possibly inside read_balance) and the call to generic_make_request(). I cannot yet see how that would happen. Can you check if the is a repeatable observation? Is nr_pending.counter always '1' on the loop device? Thanks, NeilBrown --=-=-= Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQIzBAEBCAAdFiEEG8Yp69OQ2HB7X0l6Oeye3VZigbkFAlhKSM8ACgkQOeye3VZi gbkTgQ//cESL8mIe6QiKgcO9gWYvFP6VIXUUBXm8uleeNQF1ybG/TWHNEPiMjikI Xw/cmeHbZR1waTjHdt16SEB/9iJZBTz01yc5931OrPEo2aYPz/C9hvVm4itu7+lb Sh5BVnTW+HI+ItTr71UIhB2zwNXrVxQvIloeIbLZv/SyOxWtVw2OSs4TY/kTMDi2 o9nirZIIPbHadqIivDiUrLhCnzsIst6wsO4FxoJC3D04vbyusJavSjtw4jvdxo8J D+0N8gnP4NoV7DVEKpT8w0dDq1npyT6bCrCC53mqJlw/nX4rL+nbew3QF0Qop3S+ 2SCL0nqefVieFNBh3eL2vJQNPykqVm/DwJ/geNyVQ3GzdAZcvKjSLenPBmehUBNp TnklxsVTsixgjgIulD1s4c0//qby+s1PnnWI3rno0nk93RzLD2YPc4QqLxT2ovMU J3oC9oAE690Wpe/cnvsZoZQJ8VKFtYKZhVrd1wjD9nuDLBbhfrPjKTxHt4M8KR5H WgYqiMI5cbDG3fDs8wG3zOinIqihvxciWIlBJ/FR+n5Km0BXVcMktZgB5NWGwgRL SNhhpkeA2V7/k+DiN0hFZeFDwBbbdRR/OK7K3ohXkW9di2Qv8grjIiNx04nKkkIr ZEZa05pwfiTpGoyso6yUPsheqbrlFD6sfpHOjp1zzr58V2nXwUU= =FlF/ -----END PGP SIGNATURE----- --=-=-=--