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authorTrond Myklebust <trond.myklebust@primarydata.com>2015-02-22 16:35:36 -0500
committerTrond Myklebust <trond.myklebust@primarydata.com>2015-03-01 23:23:06 -0500
commit6c441c254eea2354d686be7f5544bcd79fb6a61f (patch)
treeb5b45b9dc69afbb1bbd91ec2eeaee0a0553ac540 /fs/nfs
parent3235b40303b6f609c446275d0e7f6f9f4fe94156 (diff)
NFS: Don't invalidate a submounted dentry in nfs_prime_dcache()
If we're traversing a directory which contains a submounted filesystem, or one that has a referral, the NFS server that is processing the READDIR request will often return information for the underlying (mounted-on) directory. It may, or may not, also return filehandle information. If this happens, and the lookup in nfs_prime_dcache() returns the dentry for the submounted directory, the filehandle comparison will fail, and we call d_invalidate(). Post-commit 8ed936b5671bf ("vfs: Lazily remove mounts on unlinked files and directories."), this means the entire subtree is unmounted. The following minimal patch addresses this problem by punting on the invalidation if there is a submount. Kudos to Neil Brown <neilb@suse.de> for having tracked down this issue (see link). Reported-by: Nix <nix@esperi.org.uk> Link: http://lkml.kernel.org/r/87iofju9ht.fsf@spindle.srvr.nix Cc: stable@vger.kernel.org # 3.18+ Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Diffstat (limited to 'fs/nfs')
-rw-r--r--fs/nfs/dir.c6
1 files changed, 6 insertions, 0 deletions
diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index 9b0c55cb2a2e..4ad7fff9ccaf 100644
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -469,6 +469,8 @@ void nfs_prime_dcache(struct dentry *parent, struct nfs_entry *entry)
struct inode *inode;
int status;
+ if (!(entry->fattr->valid & NFS_ATTR_FATTR_FSID))
+ return;
if (filename.name[0] == '.') {
if (filename.len == 1)
return;
@@ -479,6 +481,10 @@ void nfs_prime_dcache(struct dentry *parent, struct nfs_entry *entry)
dentry = d_lookup(parent, &filename);
if (dentry != NULL) {
+ /* Is there a mountpoint here? If so, just exit */
+ if (!nfs_fsid_equal(&NFS_SB(dentry->d_sb)->fsid,
+ &entry->fattr->fsid))
+ goto out;
if (nfs_same_file(dentry, entry)) {
nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
status = nfs_refresh_inode(dentry->d_inode, entry->fattr);