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nfsd: Fix possible BUG_ON firing in set_change_info

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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>
Cc: stable@kernel.org
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
This commit is contained in:
Neil Brown 2010-12-02 11:14:30 +11:00 committed by J. Bruce Fields
parent ed2849d3ec
commit c1ac3ffcd0
2 changed files with 14 additions and 13 deletions
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6
fs/nfsd/nfs3xdr.c
View file

@ -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;
}

21
fs/nfsd/xdr4.h
View file

@ -484,18 +484,17 @@ 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 *);