[PATCH] VFS: Make d_materialise_unique() enforce directory uniqueness

If the caller tries to instantiate a directory using an inode that already
has a dentry alias, then we attempt to rename the existing dentry instead
of instantiating a new one.  Fail with an ELOOP error if the rename would
affect one of our parent directories.

This behaviour is needed in order to avoid issues such as

  http://bugzilla.kernel.org/show_bug.cgi?id=7178

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: Miklos Szeredi <miklos@szeredi.hu>
Cc: Maneesh Soni <maneesh@in.ibm.com>
Cc: Dipankar Sarma <dipankar@in.ibm.com>
Cc: Neil Brown <neilb@cse.unsw.edu.au>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Trond Myklebust
2006-10-21 10:24:20 -07:00
committed by Linus Torvalds
parent 3f7705eab6
commit 9eaef27b36
2 changed files with 105 additions and 37 deletions

View File

@@ -935,8 +935,11 @@ static struct dentry *nfs_lookup(struct inode *dir, struct dentry * dentry, stru
no_entry:
res = d_materialise_unique(dentry, inode);
if (res != NULL)
if (res != NULL) {
if (IS_ERR(res))
goto out_unlock;
dentry = res;
}
nfs_renew_times(dentry);
nfs_set_verifier(dentry, nfs_save_change_attribute(dir));
out_unlock:
@@ -1132,6 +1135,8 @@ static struct dentry *nfs_readdir_lookup(nfs_readdir_descriptor_t *desc)
alias = d_materialise_unique(dentry, inode);
if (alias != NULL) {
dput(dentry);
if (IS_ERR(alias))
return NULL;
dentry = alias;
}