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| author | Trond Myklebust <trond.myklebust@primarydata.com> | 2015-02-22 22:35:36 +0100 |
|---|---|---|
| committer | Trond Myklebust <trond.myklebust@primarydata.com> | 2015-03-02 05:23:06 +0100 |
| commit | 6c441c254eea2354d686be7f5544bcd79fb6a61f (patch) | |
| tree | b5b45b9dc69afbb1bbd91ec2eeaee0a0553ac540 /fs | |
| parent | NFSv4: Set a barrier in the update_changeattr() helper (diff) | |
| download | linux-6c441c254eea2354d686be7f5544bcd79fb6a61f.tar.xz linux-6c441c254eea2354d686be7f5544bcd79fb6a61f.zip | |
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')
| -rw-r--r-- | fs/nfs/dir.c | 6 |
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); |