2015-04-03 18:36:04

by Anna Schumaker

[permalink] [raw]
Subject: [PATCH] nfs: Fetch MOUNTED_ON_FILEID when updating an inode

2ef47eb1 (NFS: Fix use of nfs_attr_use_mounted_on_fileid()) was a good
start to fixing a circular directory structure warning for NFS v4
"junctioned" mountpoints. Unfortunately, further testing continued to
generate this error.

My server is configured like this:

anna@nfsd ~ % df
Filesystem Size Used Avail Use% Mounted on
/dev/vda1 9.1G 2.0G 6.5G 24% /
/dev/vdc1 1014M 33M 982M 4% /exports
/dev/vdc2 1014M 33M 982M 4% /exports/vol1
/dev/vdc3 1014M 33M 982M 4% /exports/vol1/vol2

anna@nfsd ~ % cat /etc/exports
/exports/ *(rw,async,no_subtree_check,no_root_squash)
/exports/vol1/ *(rw,async,no_subtree_check,no_root_squash)
/exports/vol1/vol2 *(rw,async,no_subtree_check,no_root_squash)

I've been running chown across the entire mountpoint twice in a row to
hit this problem. The first run succeeds, but the second one fails with
the circular directory warning along with:

anna@client ~ % dmesg
[Apr 3 14:28] NFS: server 192.168.100.204 error: fileid changed
fsid 0:39: expected fileid 0x100080, got 0x80

WHere 0x80 is the mountpoint's fileid and 0x100080 is the mounted-on
fileid.

This patch fixes the issue by requesting an updated mounted-on fileid
from the server during nfs_update_inode(), and then checking that the
fileid stored in the nfs_inode matches either the fileid or mounted-on
fileid returned by the server.

Signed-off-by: Anna Schumaker <[email protected]>
---
fs/nfs/inode.c | 15 ++++++++++++++-
fs/nfs/nfs4proc.c | 3 ++-
2 files changed, 16 insertions(+), 2 deletions(-)

diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c
index d42dff6..0d1deb0 100644
--- a/fs/nfs/inode.c
+++ b/fs/nfs/inode.c
@@ -1588,6 +1588,19 @@ int nfs_post_op_update_inode_force_wcc(struct inode *inode, struct nfs_fattr *fa
}
EXPORT_SYMBOL_GPL(nfs_post_op_update_inode_force_wcc);

+
+static inline bool nfs_fileid_valid(struct nfs_inode *nfsi,
+ struct nfs_fattr *fattr)
+{
+ bool ret1 = true, ret2 = true;
+
+ if (fattr->valid & NFS_ATTR_FATTR_FILEID)
+ ret1 = (nfsi->fileid == fattr->fileid);
+ if (fattr->valid & NFS_ATTR_FATTR_MOUNTED_ON_FILEID)
+ ret2 = (nfsi->fileid == fattr->mounted_on_fileid);
+ return ret1 || ret2;
+}
+
/*
* Many nfs protocol calls return the new file attributes after
* an operation. Here we update the inode to reflect the state
@@ -1614,7 +1627,7 @@ static int nfs_update_inode(struct inode *inode, struct nfs_fattr *fattr)
nfs_display_fhandle_hash(NFS_FH(inode)),
atomic_read(&inode->i_count), fattr->valid);

- if ((fattr->valid & NFS_ATTR_FATTR_FILEID) && nfsi->fileid != fattr->fileid) {
+ if (!nfs_fileid_valid(nfsi, fattr)) {
printk(KERN_ERR "NFS: server %s error: fileid changed\n"
"fsid %s: expected fileid 0x%Lx, got 0x%Lx\n",
NFS_SERVER(inode)->nfs_client->cl_hostname,
diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index 9ff8c63..6d48f37 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -185,7 +185,8 @@ const u32 nfs4_fattr_bitmap[3] = {
| FATTR4_WORD1_SPACE_USED
| FATTR4_WORD1_TIME_ACCESS
| FATTR4_WORD1_TIME_METADATA
- | FATTR4_WORD1_TIME_MODIFY,
+ | FATTR4_WORD1_TIME_MODIFY
+ | FATTR4_WORD1_MOUNTED_ON_FILEID,
#ifdef CONFIG_NFS_V4_SECURITY_LABEL
FATTR4_WORD2_SECURITY_LABEL
#endif
--
2.3.5