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authorAl Viro <viro@zeniv.linux.org.uk>2018-05-11 17:03:19 -0400
committerAl Viro <viro@zeniv.linux.org.uk>2018-05-21 14:30:10 -0400
commit3819bb0d79f50b05910db5bdc6d9ef512184e3b1 (patch)
tree471f4930a15a15c6e482fc0284fef824e02dcee4 /fs/nfsd
parent9c3e9025a3f7ed25c99a0add8af65431c8043800 (diff)
downloadblackbird-op-linux-3819bb0d79f50b05910db5bdc6d9ef512184e3b1.tar.gz
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nfsd: vfs_mkdir() might succeed leaving dentry negative unhashed
That can (and does, on some filesystems) happen - ->mkdir() (and thus vfs_mkdir()) can legitimately leave its argument negative and just unhash it, counting upon the lookup to pick the object we'd created next time we try to look at that name. Some vfs_mkdir() callers forget about that possibility... Acked-by: J. Bruce Fields <bfields@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'fs/nfsd')
-rw-r--r--fs/nfsd/vfs.c22
1 files changed, 22 insertions, 0 deletions
diff --git a/fs/nfsd/vfs.c b/fs/nfsd/vfs.c
index 2410b093a2e6..b0555d7d8200 100644
--- a/fs/nfsd/vfs.c
+++ b/fs/nfsd/vfs.c
@@ -1201,6 +1201,28 @@ nfsd_create_locked(struct svc_rqst *rqstp, struct svc_fh *fhp,
break;
case S_IFDIR:
host_err = vfs_mkdir(dirp, dchild, iap->ia_mode);
+ if (!host_err && unlikely(d_unhashed(dchild))) {
+ struct dentry *d;
+ d = lookup_one_len(dchild->d_name.name,
+ dchild->d_parent,
+ dchild->d_name.len);
+ if (IS_ERR(d)) {
+ host_err = PTR_ERR(d);
+ break;
+ }
+ if (unlikely(d_is_negative(d))) {
+ dput(d);
+ err = nfserr_serverfault;
+ goto out;
+ }
+ dput(resfhp->fh_dentry);
+ resfhp->fh_dentry = dget(d);
+ err = fh_update(resfhp);
+ dput(dchild);
+ dchild = d;
+ if (err)
+ goto out;
+ }
break;
case S_IFCHR:
case S_IFBLK:
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