Date: Tue, 26 Oct 2021 23:46:59 +0000 From: bugzilla-noreply@freebsd.org To: bugs@FreeBSD.org Subject: [Bug 259071] Read past EoF in NFS client and fusefs Message-ID: <bug-259071-227-66i9nmYIao@https.bugs.freebsd.org/bugzilla/> In-Reply-To: <bug-259071-227@https.bugs.freebsd.org/bugzilla/> References: <bug-259071-227@https.bugs.freebsd.org/bugzilla/>
next in thread | previous in thread | raw e-mail | index | archive | help
https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D259071 --- Comment #7 from Rick Macklem <rmacklem@FreeBSD.org> --- Created attachment 229053 --> https://bugs.freebsd.org/bugzilla/attachment.cgi?id=3D229053&action= =3Dedit timestamp file mods so Lookup can discard stale attributes against Writing Similar to attachment #228973, I believe there could be a race between the = NFS client VOP_LOOKUP() and file Writing that could result in stale file attributes being loaded into the NFS vnode by VOP_LOOKUP(). I have not been able to reproduce a failure due to this race, but I believe that there are two possibilities: The Lookup RPC happens while VOP_WRITE() is being executed and loads stale = file attributes after VOP_WRITE() returns when it has already completed the Write/Commit RPC(s).=20 --> For this case, setting the local modify timestamp at the end of VOP_WRI= TE()=20 should ensure that stale file attributes are not loaded. The Lookup RPC occurs after VOP_WRITE() has returned, while asynchronous=20 Write/Commit RPCs are in progress and then is blocked by the vnode held by VOP_OPEN/VOP_CLOSE/VOP_FSYNC which will flush writes via ncl_flush() or ncl_vinvalbuf(), clearing the NMODIFIED flag (which indicates Writes-in-progress). The VOP_LOOKUP() then acquires the NFS vnode lock and fills in stale file attributes.=20 --> Setting the local modify timestamp in ncl_flsuh() and ncl_vinvalbuf() w= hen=20 they clear NMODIFIED should ensure that stale file attributes are not=20 loaded. This patch does the above. --=20 You are receiving this mail because: You are the assignee for the bug.=
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?bug-259071-227-66i9nmYIao>