Message-ID: <20101101175854.GA3550@elliptictech.com>
Date:	Mon, 1 Nov 2010 13:58:54 -0400
From:	Nick Bowler <nbowler@...iptictech.com>
To:	linux-kernel@...r.kernel.org
Cc:	Chuck Lever <chuck.lever@...cle.com>,
	"J. Bruce Fields" <bfields@...hat.com>
Subject: Regression, bisected: sqlite locking failure on nfs

After installing 2.6.37-rc1, attempting to use sqlite in any capacity on
NFS gives a locking error:

  % echo 'select * from blah;' | sqlite3 blah.sqlite
  Error: near line 1: database is locked

  % echo 'create table blargh(INT);' | sqlite3 blargh.sqlite
  Error: near line 1: database is locked

The result is that a lot of high-profile applications which make use of
sqlite fail mysteriously.  Bisection reveals the following, and
reverting the implicated commit solves the issue:

9247685088398cf21bcb513bd2832b4cd42516c4 is the first bad commit
commit 9247685088398cf21bcb513bd2832b4cd42516c4
Author: Chuck Lever <chuck.lever@...cle.com>
Date:   Wed Oct 20 11:53:01 2010 -0400

    SUNRPC: Properly initialize sock_xprt.srcaddr in all cases
    
    The source address field in the transport's sock_xprt is initialized
    ONLY IF the RPC application passed a pointer to a source address
    during the call to rpc_create().  However, xs_bind() subsequently uses
    the value of this field without regard to whether the source address
    was initialized during transport creation or not.
    
    So far we've been lucky: the uninitialized value of this field is
    zeroes.  xs_bind(), until recently, used only the sin[6]_addr field in
    this sockaddr, and all zeroes is a valid value for this: it means
    ANYADDR.  This is a happy coincidence.
    
    However, xs_bind() now wants to use the sa_family field as well, and
    expects it to be initialized to something other than zero.
    
    Therefore, the source address sockaddr field should be fully
    initialized at transport create time in _every_ case, not just when
    the RPC application wants to use a specific bind address.
    
    Bruce added a workaround for this missing initialization by adjusting
    commit 6bc9638a, but the "right" way to do this is to ensure that the
    source address sockaddr is always correctly initialized from the
    get-go.
    
    This patch doesn't introduce a behavior change.  It's simply a
    clean-up of Bruce's fix, to prevent future problems of this kind.  It
    may look like overkill, but
    
      a) it clearly documents the default initial value of this field,
    
      b) it doesn't assume that the sockaddr_storage memory is first
         initialized to any particular value, and
    
      c) it will fail verbosely if some unknown address family is passed
         in
    
    Originally introduced by commit d3bc9a1d.
    
    Signed-off-by: Chuck Lever <chuck.lever@...cle.com>
    Signed-off-by: J. Bruce Fields <bfields@...hat.com>

:040000 040000 843e2423b5a45f7bc13b9e30cc8e5bcb072dbb8f 7148b5256ce78fd5c98a01f1bdcac46faa80f773 M	net

git bisect start
# bad: [c8ddb2713c624f432fa5fe3c7ecffcdda46ea0d4] Linux 2.6.37-rc1
git bisect bad c8ddb2713c624f432fa5fe3c7ecffcdda46ea0d4
# good: [f6f94e2ab1b33f0082ac22d71f66385a60d8157f] Linux 2.6.36
git bisect good f6f94e2ab1b33f0082ac22d71f66385a60d8157f
# good: [33081adf8b89d5a716d7e1c60171768d39795b39] Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound-2.6
git bisect good 33081adf8b89d5a716d7e1c60171768d39795b39
# bad: [00ebb6382b8d9c7c15b5f8ad230670d8161d38dd] Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/cjb/mmc
git bisect bad 00ebb6382b8d9c7c15b5f8ad230670d8161d38dd
# bad: [520045db940a381d2bee1c1b2179f7921b40fb10] Merge branches 'upstream/xenfs' and 'upstream/core' of git://git.kernel.org/pub/scm/linux/kernel/git/jeremy/xen
git bisect bad 520045db940a381d2bee1c1b2179f7921b40fb10
# bad: [4390110fef9e5c64e10c6ca19d586932242c9a8a] Merge branch 'for-2.6.37' of git://linux-nfs.org/~bfields/linux
git bisect bad 4390110fef9e5c64e10c6ca19d586932242c9a8a
# good: [7b6181e06841f5ad15c4ff708b967b4db65a64de] Merge branch 'omap-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tmlind/linux-omap-2.6
git bisect good 7b6181e06841f5ad15c4ff708b967b4db65a64de
# good: [e0e170bd7ded2ec16e2813d63c0faff43193fde8] Merge branch 'next' of git://git.monstr.eu/linux-2.6-microblaze
git bisect good e0e170bd7ded2ec16e2813d63c0faff43193fde8
# good: [22f793268de3b4dff8abfcd873ba7afc1f34224f] sunrpc: Factor out v4 sockets creation
git bisect good 22f793268de3b4dff8abfcd873ba7afc1f34224f
# good: [a4dd8dce14014665862ce7911b38cb2c69e366dd] Merge branch 'nfs-for-2.6.37' of git://git.linux-nfs.org/projects/trondmy/nfs-2.6
git bisect good a4dd8dce14014665862ce7911b38cb2c69e366dd
# bad: [cd5b814458e5554457c6e62f17aed122145b065e] nfsd4: don't cache seq_misordered replies
git bisect bad cd5b814458e5554457c6e62f17aed122145b065e
# good: [8c14ff2aaf26d58aa2258a59bd419c906d105938] sunrpc: Remove UDP worker wrappers
git bisect good 8c14ff2aaf26d58aa2258a59bd419c906d105938
# good: [8f3a6de313391b6910aa7db185eb9f3e930a51cf] sunrpc: Turn list_for_each-s into the ..._entry-s
git bisect good 8f3a6de313391b6910aa7db185eb9f3e930a51cf
# good: [4232e8634ad82c5a53389e4016de15a8b15c09c3] SUNRPC: Use conventional switch statement when reclassifying sockets
git bisect good 4232e8634ad82c5a53389e4016de15a8b15c09c3
# bad: [9247685088398cf21bcb513bd2832b4cd42516c4] SUNRPC: Properly initialize sock_xprt.srcaddr in all cases
git bisect bad 9247685088398cf21bcb513bd2832b4cd42516c4

-- 
Nick Bowler, Elliptic Technologies (http://www.elliptictech.com/)
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