From 7dc72d5f7a0ec97a53e126c46e2cbd2560757955 Mon Sep 17 00:00:00 2001 From: Trond Myklebust Date: Thu, 22 Sep 2016 13:38:52 -0400 Subject: [PATCH] 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 --- fs/nfs/dir.c | 16 +++++++++++----- 1 file changed, 11 insertions(+), 5 deletions(-) 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); -- 2.20.1