From: Trond Myklebust Date: Thu, 22 Sep 2016 17:38:52 +0000 (-0400) Subject: NFS: Fix inode corruption in nfs_prime_dcache() X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=7dc72d5f7a0ec97a53e126c46e2cbd2560757955;p=GitHub%2Fmoto-9609%2Fandroid_kernel_motorola_exynos9610.git NFS: Fix inode corruption in nfs_prime_dcache() Due to inode number reuse in filesystems, we can end up corrupting the inode on our client if we apply the file attributes without ensuring that the filehandle matches. Typical symptoms include spurious "mode changed" reports in the syslog. We still do want to ensure that we don't invalidate the dentry if the inode number matches, but we don't have a filehandle. Fixes: fa9233699cc1 ("NFS: Don't require a filehandle to refresh...") Signed-off-by: Trond Myklebust Cc: stable@vger.kernel.org # v4.0+ Tested-by: Oleg Drokin Signed-off-by: Anna Schumaker --- diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c index eb095f77c39d..2bade7909dec 100644 --- a/fs/nfs/dir.c +++ b/fs/nfs/dir.c @@ -435,11 +435,11 @@ int nfs_same_file(struct dentry *dentry, struct nfs_entry *entry) return 0; nfsi = NFS_I(inode); - if (entry->fattr->fileid == nfsi->fileid) - return 1; - if (nfs_compare_fh(entry->fh, &nfsi->fh) == 0) - return 1; - return 0; + if (entry->fattr->fileid != nfsi->fileid) + return 0; + if (entry->fh->size && nfs_compare_fh(entry->fh, &nfsi->fh) != 0) + return 0; + return 1; } static @@ -525,6 +525,8 @@ again: &entry->fattr->fsid)) goto out; if (nfs_same_file(dentry, entry)) { + if (!entry->fh->size) + goto out; nfs_set_verifier(dentry, nfs_save_change_attribute(dir)); status = nfs_refresh_inode(d_inode(dentry), entry->fattr); if (!status) @@ -537,6 +539,10 @@ again: goto again; } } + if (!entry->fh->size) { + d_lookup_done(dentry); + goto out; + } inode = nfs_fhget(dentry->d_sb, entry->fh, entry->fattr, entry->label); alias = d_splice_alias(inode, dentry);