Date: Thu, 9 Aug 2018 14:10:04 +0300 From: Konstantin Belousov <kostikbel@gmail.com> To: Rick Macklem <rmacklem@uoguelph.ca> Cc: "freebsd-current@FreeBSD.org" <freebsd-current@FreeBSD.org>, "peter@holm.cc" <peter@holm.cc> Subject: Re: ffs_truncate3 panics Message-ID: <20180809111004.GK1884@kib.kiev.ua> In-Reply-To: <YTOPR0101MB18205CDE34ABCC2345C3F172DD250@YTOPR0101MB1820.CANPRD01.PROD.OUTLOOK.COM> References: <YTOPR0101MB18206289DDED97BE9DD38D14DD270@YTOPR0101MB1820.CANPRD01.PROD.OUTLOOK.COM> <20180807131445.GC1884@kib.kiev.ua> <YTOPR0101MB18207C97903D3058A15091FFDD260@YTOPR0101MB1820.CANPRD01.PROD.OUTLOOK.COM> <20180808221647.GH1884@kib.kiev.ua> <YTOPR0101MB18205CDE34ABCC2345C3F172DD250@YTOPR0101MB1820.CANPRD01.PROD.OUTLOOK.COM>
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On Thu, Aug 09, 2018 at 01:39:20AM +0000, Rick Macklem wrote: > Konstantin Belousov wrote: > [stuff snipped] > >> >Can you print the only buffer on the clean queue when the panic occur ? > >> ffst3 vtyp=1 bodirty=0 boclean=1 > >> buf at 0x428a110 > >> b_flags = 0x20001020<vmio,reuse,cache>, b_xflags=0x2<clean>, b_vflags=0x0 > >> b_error = 0, b_bufsize = 4096, b_bcount = 4096, b_resid = 0 > >> b_bufobj = (0xfd8ba94), b_data = 0x5170000, b_blkno = -1, b_lblkno = -1, b_dep = 0 > >> b_kvabase = 0x5170000, b_kvasize = 32768 > >So the buffer was indeed for extended attrs, and never written to the disk. > >I am quite interested what was the inode content prior to the truncation, > >esp. the di_extsize. > Just in case it wasn't clear, this buffer is on the clean list and not the dirty one. > (Does this mean it somehow got onto the "clean list" without being written to disk?) > > >Could you try to formulate a way to reproduce the panic so that Peter > >can recreate it, please ? > I doubt it. It would require him doing a pNFS setup with multiple systems. > (At least that is the only way I reproduce it and I sometimes go a week of testing > before I see them.) > It would be great to have more testers for the pNFS server stuff, but I doubt it > would fit into Peter's setup? > > I can add printf()s anywhere you suggest, but I'm not sure how you would catch > this case sooner? (For example, I could print out di_extsize at the beginning of > ffs_truncate(), if that would help?) May be, add a loop at the beginning of ffs_truncate(), over all buffers on both clean and dirty queues, calculating number of buffers with b_lblkno < 0 and >= -UFS_NXADDR. Print some diagnostic if such buffer is detected but di_extsize is zero. BTW, does NFS server use extended attributes ? What for ? Can you, please, point out the code which does this ?
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