From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794065200; b=qjxaE1eOYu1aIeNiST+FJznDEsZ3Z44fDMM60oGuRqgdvgWp8hM7LRJN7gDeG308eC14 bcxrm1sZJFUru7VBtcB5yf7HEAgXhrcR0d3PYZw9Jacwnme4yFPZbVkfJLa31aarm9pRh jp7lO4TvgAIeqasHBmZYAGq7n/xCuwzqRcJm+94EwBr83Dql4c4tvGPq0JPs74+c9VRyS yZ+k8tu6ZdRsVi0QiPDrW/LzKlFCIO6jwvsOOzZwhZ6fM/Hb0iMeCr8WYU2RYOdgocs3U 5jEkn0GiETxHFCraQRYyxpZSkem31Bhu8Smqq2jcBWwt3tChvG46YwLIzNFXLDoXEww== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794065200; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:User-Agent:X-stable:X-Patchwork-Hint: MIME-Version:Content-Transfer-Encoding; bh=OHScwIbTsfBcu3NPXKk84TmeS8mGVK0qKPnYvo3XrnA=; b=kzr54afdlF/keKxrfZ7oUkVqYKc1QRrkS6bG7IHZWJLbSoOxDuXK4GIAn9MG/E/M8G4i ZehW3ouOSugQD5miVwAbTrAMUuwzOpbVJ0grUylLcZNOOsRLrNwiBKTh3vUXMZsHoxAe4 dnF4gsCOZQ7Q8lT1o0vghZr8HcFph4EizARKALlHju/AuFYgsA3RssLCE2FaAlB+1djcf DdxHjt4u4pcrh0Wj5XXcWNlSSvzXNWikGwKhI90ZPfI6kYzpVD9gC7AE0h6K9fuwnP1mh KQpV7Y8Wj9GRj5qLQbhwwYgt9UGLLVbJ4mGzZW4OdsLYr3wk77HvK9qF+pV4PUh4v+w== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b="iHH2e3j/"; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 03F8E606A32E; Sat, 7 Nov 2026 15:26:40 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=iHH2e3j/ Received: by smtp.kernel.org (Postfix) with ESMTPSA id ADB5B1F0089F; Sat, 7 Nov 2026 15:26:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1794065199; bh=OHScwIbTsfBcu3NPXKk84TmeS8mGVK0qKPnYvo3XrnA=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=iHH2e3j/BcP3lssujmE95H2Xh5XdQghs/+sQwoF3OSil15HmiZ651QL+kDJ2ojiwP fX78Vmw60cdqj8DxQCQqdWdUy24Zp5kErAsgm/W2/pOcPTxEQqJBsNnQaJ0VoKLaBh +ndCrgsUfQYxRAaDZWH0y0VrXOrp/36rCvOUH12M= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Joseph Qi , Andrew Morton , Heming Zhao , Anderson Ferneda , Mark Fasheh , Joel Becker , Sasha Levin Subject: [PATCH 7.3 0999/1257] ocfs2: use the stored hash when checking xattr bucket collision Date: Sat, 7 Nov 2026 08:54:55 -0500 Message-ID: <20261107135006.947172383@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261107134939.434104957@linuxfoundation.org> References: <20261107134939.434104957@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore X-Mailing-List: stable@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 7.3-stable review patch. If anyone has any objections, please let me know. ------------------ From: Joseph Qi [ Upstream commit e39baff18b85cf8956aee138d7944b6581e8ba36 ] ocfs2_check_xattr_bucket_collision() decides whether splitting a full bucket can make room for the entry being set by recomputing the hash of the name: u32 name_hash = ocfs2_xattr_name_hash(inode, name, strlen(name)); if (name_hash != le32_to_cpu(xh->xh_entries[0].xe_name_hash)) return 0; For a new entry that is the hash it will be stored under, so comparing it is correct. An existing entry keeps the hash it already has: an update never rewrites xe_name_hash, since ocfs2_xa_add_entry() is the only writer of that field for a real entry and ocfs2_xa_prepare_entry() calls it only when loc->xl_entry is NULL. An entry stored by a kernel that sign-extended the name bytes when hashing can still be updated, because ocfs2_xattr_find_entry() searches a non-indexed xattr block by memcmp on the name and never looks at xe_name_hash. Growing it past the space left in the block converts the block into a tree, ocfs2_cp_xattr_block_to_bucket() fills the bucket in stored hash order, and the update runs out of room in the bucket too. The collision check then compares the unsigned hash against the legacy hashes in the bucket and reports no collision. ocfs2_xattr_set_entry_index_block() goes on to allocate a bucket that ocfs2_divide_xattr_bucket() cannot fill: a bucket whose entries all share one hash has no divide position, so all it does is append an empty bucket with a sentinel hash one above the last entry's. The re-search that follows depends on where the unsigned hash sorts. Below the legacy ones, it comes back to the full bucket and the set fails with -ENOSPC, having grown the tree for nothing. Above them, it lands on the new empty bucket, which ocfs2_xattr_bucket_find() handles explicitly and ocfs2_find_xe_in_bucket() scans zero times, so the set stores a second copy of the entry under the unsigned hash and returns success. The original stays in the full bucket, listxattr reports the name twice and getxattr returns the new copy. Pass the hash the entry is stored under instead: the stored one for an existing entry, the unsigned one for a new entry. A tree whose entries are all stored under the unsigned hash sees no change, since there the two are the same value. Link: https://lore.kernel.org/20261009083002.2621201-3-joseph.qi@linux.alibaba.com Fixes: 3bc753c06dd0 ("kbuild: treat char as always unsigned") Signed-off-by: Joseph Qi Signed-off-by: Andrew Morton Reviewed-by: Heming Zhao Cc: Anderson Ferneda Cc: Mark Fasheh Cc: Joel Becker Cc: # 6.2+ Signed-off-by: Sasha Levin --- fs/ocfs2/xattr.c | 27 +++++++++++++++++---------- 1 file changed, 17 insertions(+), 10 deletions(-) diff --git a/fs/ocfs2/xattr.c b/fs/ocfs2/xattr.c index 1beb4937fd19c..84a47bf30ed5b 100644 --- a/fs/ocfs2/xattr.c +++ b/fs/ocfs2/xattr.c @@ -5769,16 +5769,14 @@ static int ocfs2_rm_xattr_cluster(struct inode *inode, /* * check whether the xattr bucket is filled up with the same hash value. - * If we want to insert the xattr with the same hash, return -ENOSPC. - * If we want to insert a xattr with different hash value, go ahead - * and ocfs2_divide_xattr_bucket will handle this. + * If the entry being set carries that same hash, return -ENOSPC, since + * ocfs2_divide_xattr_bucket() has no divide position to work with. + * Otherwise go ahead and ocfs2_divide_xattr_bucket() will handle this. */ -static int ocfs2_check_xattr_bucket_collision(struct inode *inode, - struct ocfs2_xattr_bucket *bucket, - const char *name) +static int ocfs2_check_xattr_bucket_collision(struct ocfs2_xattr_bucket *bucket, + u32 name_hash) { struct ocfs2_xattr_header *xh = bucket_xh(bucket); - u32 name_hash = ocfs2_xattr_name_hash(inode, name, strlen(name)); if (name_hash != le32_to_cpu(xh->xh_entries[0].xe_name_hash)) return 0; @@ -5847,6 +5845,7 @@ static int ocfs2_xattr_set_entry_index_block(struct inode *inode, struct ocfs2_xattr_search *xs, struct ocfs2_xattr_set_ctxt *ctxt) { + u32 name_hash; int ret; trace_ocfs2_xattr_set_entry_index_block(xi->xi_name); @@ -5866,10 +5865,18 @@ static int ocfs2_xattr_set_entry_index_block(struct inode *inode, * the maximum number of collisions we will allow for then is * one bucket's worth, so check it here whether we need to * add a new bucket for the insert. + * + * An existing entry keeps the hash it was stored under, and that is + * the hash a split has to work with. A new entry is stored under the + * unsigned one, which is what ocfs2_xa_add_entry() will write. */ - ret = ocfs2_check_xattr_bucket_collision(inode, - xs->bucket, - xi->xi_name); + if (xs->not_found) + name_hash = ocfs2_xattr_name_hash(inode, xi->xi_name, + xi->xi_name_len); + else + name_hash = le32_to_cpu(xs->here->xe_name_hash); + + ret = ocfs2_check_xattr_bucket_collision(xs->bucket, name_hash); if (ret) { mlog_errno(ret); goto out; -- 2.53.0