From: Neil Brown Date: Thu, 2 Dec 2010 00:14:30 +0000 (+1100) Subject: nfsd: Fix possible BUG_ON firing in set_change_info X-Git-Tag: v2.6.27.58~9 X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=27e4f346bd7900dec3a2bcea269303b9fcd947fe;p=thirdparty%2Fkernel%2Fstable.git nfsd: Fix possible BUG_ON firing in set_change_info commit c1ac3ffcd0bc7e9617f62be8c7043d53ab84deac upstream. If vfs_getattr in fill_post_wcc returns an error, we don't set fh_post_change. For NFSv4, this can result in set_change_info triggering a BUG_ON. i.e. fh_post_saved being zero isn't really a bug. So: - instead of BUGging when fh_post_saved is zero, just clear ->atomic. - if vfs_getattr fails in fill_post_wcc, take a copy of i_ctime anyway. This will be used i seg_change_info, but not overly trusted. - While we are there, remove the pointless 'if' statements in set_change_info. There is no harm setting all the values. Signed-off-by: NeilBrown Signed-off-by: J. Bruce Fields Signed-off-by: Greg Kroah-Hartman Signed-off-by: Willy Tarreau --- diff --git a/fs/nfsd/nfs3xdr.c b/fs/nfsd/nfs3xdr.c index 17d0dd997204a..05569c7d94f94 100644 --- a/fs/nfsd/nfs3xdr.c +++ b/fs/nfsd/nfs3xdr.c @@ -272,9 +272,11 @@ void fill_post_wcc(struct svc_fh *fhp) err = vfs_getattr(fhp->fh_export->ex_path.mnt, fhp->fh_dentry, &fhp->fh_post_attr); - if (err) + if (err) { fhp->fh_post_saved = 0; - else + /* Grab the ctime anyway - set_change_info might use it */ + fhp->fh_post_attr.ctime = fhp->fh_dentry->d_inode->i_ctime; + } else fhp->fh_post_saved = 1; } diff --git a/include/linux/nfsd/xdr4.h b/include/linux/nfsd/xdr4.h index 27bd3e38ec5ad..dca69e339f972 100644 --- a/include/linux/nfsd/xdr4.h +++ b/include/linux/nfsd/xdr4.h @@ -424,8 +424,8 @@ struct nfsd4_compoundres { static inline void set_change_info(struct nfsd4_change_info *cinfo, struct svc_fh *fhp) { - BUG_ON(!fhp->fh_pre_saved || !fhp->fh_post_saved); - cinfo->atomic = 1; + BUG_ON(!fhp->fh_pre_saved); + cinfo->atomic = fhp->fh_post_saved; cinfo->before_ctime_sec = fhp->fh_pre_ctime.tv_sec; cinfo->before_ctime_nsec = fhp->fh_pre_ctime.tv_nsec; cinfo->after_ctime_sec = fhp->fh_post_attr.ctime.tv_sec;