[PATCH] fuse: fix dereferencing dentry parent
There's no locking for ->d_revalidate, so fuse_dentry_revalidate() should use dget_parent() instead of simply dereferencing ->d_parent. Due to topology changes in the directory tree the parent could become negative or be destroyed while being used. There hasn't been any reports about this yet. Signed-off-by: Miklos Szeredi <miklos@szeredi.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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@ -138,6 +138,7 @@ static int fuse_dentry_revalidate(struct dentry *entry, struct nameidata *nd)
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struct fuse_entry_out outarg;
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struct fuse_conn *fc;
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struct fuse_req *req;
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struct dentry *parent;
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/* Doesn't hurt to "reset" the validity timeout */
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fuse_invalidate_entry_cache(entry);
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@ -151,8 +152,10 @@ static int fuse_dentry_revalidate(struct dentry *entry, struct nameidata *nd)
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if (IS_ERR(req))
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return 0;
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fuse_lookup_init(req, entry->d_parent->d_inode, entry, &outarg);
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parent = dget_parent(entry);
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fuse_lookup_init(req, parent->d_inode, entry, &outarg);
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request_send(fc, req);
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dput(parent);
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err = req->out.h.error;
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/* Zero nodeid is same as -ENOENT */
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if (!err && !outarg.nodeid)
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