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Commit c1ac3ffc authored by Neil Brown's avatar Neil Brown Committed by J. Bruce Fields
Browse files

nfsd: Fix possible BUG_ON firing in set_change_info 



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: default avatarNeilBrown <neilb@suse.de>
Cc: stable@kernel.org
Signed-off-by: default avatarJ. Bruce Fields <bfields@redhat.com>
parent ed2849d3

fs/nfsd/nfs3xdr.c

+4 −2
Original line number Diff line number Diff line
@@ -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;

}

fs/nfsd/xdr4.h

+10 −11
Original line number Diff line number Diff line
@@ -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;

	}



}



int nfs4svc_encode_voidres(struct svc_rqst *, __be32 *, void *);