From: Benny Halevy Date: Fri, 4 Jul 2008 12:38:41 +0000 (+0300) Subject: nfsd: take file and mnt write in nfs4_upgrade_open X-Git-Tag: v2.6.27-rc1~961^2~9 X-Git-Url: http://www.pilppa.org/gitweb/gitweb.cgi?a=commitdiff_plain;h=e518f0560a191269bd345178c899c790eb1ad4c8;p=linux-2.6-omap-h63xx.git nfsd: take file and mnt write in nfs4_upgrade_open testing with newpynfs revealed this warning: Jul 3 07:32:50 buml kernel: writeable file with no mnt_want_write() Jul 3 07:32:50 buml kernel: ------------[ cut here ]------------ Jul 3 07:32:50 buml kernel: WARNING: at /usr0/export/dev/bhalevy/git/linux-pnfs-bh-nfs41/include/linux/fs.h:855 drop_file_write_access+0x6b/0x7e() Jul 3 07:32:50 buml kernel: Modules linked in: nfsd auth_rpcgss exportfs nfs lockd nfs_acl sunrpc Jul 3 07:32:50 buml kernel: Call Trace: Jul 3 07:32:50 buml kernel: 6eaadc88: [<6002f471>] warn_on_slowpath+0x54/0x8e Jul 3 07:32:50 buml kernel: 6eaadcc8: [<601b790d>] printk+0xa0/0x793 Jul 3 07:32:50 buml kernel: 6eaadd38: [<601b6205>] __mutex_lock_slowpath+0x1db/0x1ea Jul 3 07:32:50 buml kernel: 6eaadd68: [<7107d4d5>] nfs4_preprocess_seqid_op+0x2a6/0x31c [nfsd] Jul 3 07:32:50 buml kernel: 6eaadda8: [<60078dc9>] drop_file_write_access+0x6b/0x7e Jul 3 07:32:50 buml kernel: 6eaaddc8: [<710804e4>] nfsd4_open_downgrade+0x114/0x1de [nfsd] Jul 3 07:32:50 buml kernel: 6eaade08: [<71076215>] nfsd4_proc_compound+0x1ba/0x2dc [nfsd] Jul 3 07:32:50 buml kernel: 6eaade48: [<71068221>] nfsd_dispatch+0xe5/0x1c2 [nfsd] Jul 3 07:32:50 buml kernel: 6eaade88: [<71312f81>] svc_process+0x3fd/0x714 [sunrpc] Jul 3 07:32:50 buml kernel: 6eaadea8: [<60039a81>] kernel_sigprocmask+0xf3/0x100 Jul 3 07:32:50 buml kernel: 6eaadee8: [<7106874b>] nfsd+0x182/0x29b [nfsd] Jul 3 07:32:50 buml kernel: 6eaadf48: [<60021cc9>] run_kernel_thread+0x41/0x4a Jul 3 07:32:50 buml kernel: 6eaadf58: [<710685c9>] nfsd+0x0/0x29b [nfsd] Jul 3 07:32:50 buml kernel: 6eaadf98: [<60021cb0>] run_kernel_thread+0x28/0x4a Jul 3 07:32:50 buml kernel: 6eaadfc8: [<60013829>] new_thread_handler+0x72/0x9c Jul 3 07:32:50 buml kernel: Jul 3 07:32:50 buml kernel: ---[ end trace 2426dd7cb2fba3bf ]--- Bruce Fields suggested this (Thanks!): maybe we need to be doing a mnt_want_write on open_upgrade and mnt_put_write on downgrade? This patch adds a call to mnt_want_write and file_take_write (which is doing the actual work). The counter-calls mnt_drop_write a file_release_write are now being properly called by drop_file_write_access in the exact path printed by the warning above. Signed-off-by: Benny Halevy Signed-off-by: J. Bruce Fields --- diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c index c29b6ed2a0b..1578d7a2667 100644 --- a/fs/nfsd/nfs4state.c +++ b/fs/nfsd/nfs4state.c @@ -1588,6 +1588,10 @@ nfs4_upgrade_open(struct svc_rqst *rqstp, struct svc_fh *cur_fh, struct nfs4_sta int err = get_write_access(inode); if (err) return nfserrno(err); + err = mnt_want_write(cur_fh->fh_export->ex_path.mnt); + if (err) + return nfserrno(err); + file_take_write(filp); } status = nfsd4_truncate(rqstp, cur_fh, open); if (status) {