| From | Paul Gortmaker <> | Subject | [34-longterm 163/209] nfsd: Fix possible BUG_ON firing in set_change_info | Date | Thu, 14 Apr 2011 13:55:21 -0400 |
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From: Neil Brown <neilb@suse.de>
===================================================================== | This is a commit scheduled for the next v2.6.34 longterm release. | | If you see a problem with using this for longterm, please comment.| =====================================================================
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 <neilb@suse.de> Signed-off-by: J. Bruce Fields <bfields@redhat.com> Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com> --- fs/nfsd/nfs3xdr.c | 6 ++++-- fs/nfsd/xdr4.h | 21 ++++++++++----------- 2 files changed, 14 insertions(+), 13 deletions(-)
diff --git a/fs/nfsd/nfs3xdr.c b/fs/nfsd/nfs3xdr.c index 2a533a0..7e84a85 100644 --- a/fs/nfsd/nfs3xdr.c +++ b/fs/nfsd/nfs3xdr.c @@ -260,9 +260,11 @@ void fill_post_wcc(struct svc_fh *fhp) err = vfs_getattr(fhp->fh_export->ex_path.mnt, fhp->fh_dentry, &fhp->fh_post_attr); fhp->fh_post_change = fhp->fh_dentry->d_inode->i_version; - 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/fs/nfsd/xdr4.h b/fs/nfsd/xdr4.h index efa3377..c1aed78 100644 --- a/fs/nfsd/xdr4.h +++ b/fs/nfsd/xdr4.h @@ -479,18 +479,17 @@ static inline bool nfsd4_not_cached(struct nfsd4_compoundres *resp) 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->change_supported = IS_I_VERSION(fhp->fh_dentry->d_inode); - if (cinfo->change_supported) { - cinfo->before_change = fhp->fh_pre_change; - cinfo->after_change = fhp->fh_post_change; - } else { - 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; - cinfo->after_ctime_nsec = fhp->fh_post_attr.ctime.tv_nsec; - } + + cinfo->before_change = fhp->fh_pre_change; + cinfo->after_change = fhp->fh_post_change; + 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; + cinfo->after_ctime_nsec = fhp->fh_post_attr.ctime.tv_nsec; + } int nfs4svc_encode_voidres(struct svc_rqst *, __be32 *, void *); -- 1.7.4.4
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