From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 78B71344D92; Fri, 17 Jul 2026 16:53:06 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784307187; cv=none; b=S02RuQHegBLDGkouxTvA5OfEme2BxEPPQDrH/pyDPCP2k2DSJBFlhoAnLZGyIIi5H+rOmyAlvhAitpbtrgeg/WOl6YoYuoOlJRr7UIWm71wSgAj1jYJd7Ua74bIpf7MoeRZxrFDNEM/otjJ5bfOQ8t37FU0bKb8HNpnn6ZhhiRI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784307187; c=relaxed/simple; bh=NdKAuaLuNewy/k63oi5OEDmdnoEMQaYx06SVbYpFGMs=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=mAkw7VhP5UIs7NWo6ItL0dRbF7MfRgeDDuOCbw6U29qLOsndabsKwY6bwFikpw2fuSxzEC2r82+FzQk7qVYlWht3cNbRuyJ9WiKbkMHZe8iuZilDQBiQcmdlRffvWZN8abIfojM+HQsG6Ij1LUBemfTWrBerw0CotH7Ua6hYFrw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=VHy4Gst6; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="VHy4Gst6" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E176C1F00A3D; Fri, 17 Jul 2026 16:53:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1784307186; bh=chNnEUS4ou1ewRr5tiT5ffA/oK+d9tifbMacz+ARlPk=; h=From:Date:Subject:References:In-Reply-To:To:Cc; b=VHy4Gst6qim3PoxXrlkcQdv8iWEI+CusiRKKwfSlfYoFTJADPluWZJgku9QUd25RC NU4b+RKNSF8Va+qCTLaFpKWu3GeJzEDLBenMLMkRMn7qaek841qELSrB75W9+C5rsp oBPIhv74YRu2HE8cbVppPdeMhZJAecythOxT1omH/P0zxmLy03t16wCTZWlaim6cT9 H6yaMInFUS9KaW9vBDTtcAzB6rPtozGpP8PcI715MXxP8rcH3Op7vYYVEoUZdCpwuv EUcsadqaXtUA8bg383nn5LPz7iuNqFb+0laZB1iRUMyA7i22zYPPj6QaLe0eRDMkDs qsebzJ20TadPA== From: Jeff Layton Date: Fri, 17 Jul 2026 12:52:36 -0400 Subject: [PATCH 1/4] btrfs: split btrfs_insert_delayed_dir_index() into prealloc and commit phases Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20260717-btrfs-enomem-v1-1-cdc9c0e265d0@kernel.org> References: <20260717-btrfs-enomem-v1-0-cdc9c0e265d0@kernel.org> In-Reply-To: <20260717-btrfs-enomem-v1-0-cdc9c0e265d0@kernel.org> To: Chris Mason , David Sterba Cc: linux-btrfs@vger.kernel.org, linux-kernel@vger.kernel.org, kernel-team@fb.com, Jeff Layton X-Mailer: b4 0.14.3 X-Developer-Signature: v=1; a=openpgp-sha256; l=8189; i=jlayton@kernel.org; h=from:subject:message-id; bh=NdKAuaLuNewy/k63oi5OEDmdnoEMQaYx06SVbYpFGMs=; b=owEBbQKS/ZANAwAKAQAOaEEZVoIVAcsmYgBqWl3v52jA/vgS/n1Zp/BrUG7LRkB+sl0A1/Sux tNzRRNxxOGJAjMEAAEKAB0WIQRLwNeyRHGyoYTq9dMADmhBGVaCFQUCalpd7wAKCRAADmhBGVaC FUPgD/sE0B06KoUGFgIf1v3+epAUTW+I77MhDtYEQG+9+4Lhg2570qhxGOm0TkHInX3VuM+vV7V PkPxaDKdq8/WarpnPx3v2tLdYf4TDlo8W1pBASqn24E1bUzzME05eOnT0uidbEiuNkIJ4nnI0as 9YBTzs8uXPrNGzM6sWzDnW8E2Bn8mijePQls/yOpa38izfJMWwIuTSDpBNCWMme8arGC613y6EO AaXpoF3Jn7D40EiRDMC/1/c438LyqsX154ssywq+GpySiBshAPXq92ZiF8LgiV4qSrB6wEWMX44 o9mkz3bLpRA8v3BqsrPkpFwJ80TEa90iWVUl7zss7ZQqoVX5WWjdvwI5MIVD4n3qEKH29y6SJre XA8rGPHBV+PXf/rjF/1ybMSMT/HbbP0XJN31dx0CXAKLVumMb12NkucROfuyqkR3o2Rdk8BQJEh Omdli/hRxpHQLy7zdPGgDkaj4UrR0wVmrNxLx6llKriC4IIh4Ls19Bkq1tXO1/mo0xjW8npMZ1r M9Wkbd6t5wH04icpF0lBHuoQ0MFNZwf/KzN0RtcQtusStUgGw/lFfV9cYi/d4/GoVsnIpb0Lf39 nartylHWS91Kaxlzr72AGdqVL3vKkb2ssAkSu6sR7GUa2c07or3JeFTZK/GlEZotZN5L9aOa0jl /0rYlVk+csJ5GUg== X-Developer-Key: i=jlayton@kernel.org; a=openpgp; fpr=4BC0D7B24471B2A184EAF5D3000E684119568215 Split btrfs_insert_delayed_dir_index() into three functions using a new btrfs_dir_index_prealloc struct to bundle the pre-allocated resources: - btrfs_prealloc_delayed_dir_index(): performs the two GFP_NOFS allocations (delayed node + delayed item) that can fail with -ENOMEM. - btrfs_insert_delayed_dir_index_prealloc(): populates the item data, inserts into the rb-tree, and reserves metadata space. Cannot fail with -ENOMEM since all allocations were done in the prealloc step. - btrfs_free_delayed_dir_index_prealloc(): frees pre-allocated resources when the caller's btree insertion fails. The original btrfs_insert_delayed_dir_index() is refactored into a thin wrapper that calls the prealloc and commit functions. This split allows callers to move the fallible memory allocations before the point of no return (the DIR_ITEM btree insertion), so that -ENOMEM can be returned cleanly without aborting the transaction. Assisted-by: LLM Signed-off-by: Jeff Layton --- fs/btrfs/delayed-inode.c | 109 ++++++++++++++++++++++++++++++++++++----------- fs/btrfs/delayed-inode.h | 17 ++++++++ 2 files changed, 102 insertions(+), 24 deletions(-) diff --git a/fs/btrfs/delayed-inode.c b/fs/btrfs/delayed-inode.c index 09795439b9fb..9d7343934eea 100644 --- a/fs/btrfs/delayed-inode.c +++ b/fs/btrfs/delayed-inode.c @@ -1469,35 +1469,73 @@ static void btrfs_release_dir_index_item_space(struct btrfs_trans_handle *trans) trans->bytes_reserved -= bytes; } -/* Will return 0, -ENOMEM or -EEXIST (index number collision, unexpected). */ -int btrfs_insert_delayed_dir_index(struct btrfs_trans_handle *trans, - const char *name, int name_len, - struct btrfs_inode *dir, - const struct btrfs_disk_key *disk_key, u8 flags, - u64 index) +/* + * Pre-allocate a delayed node and delayed item for a dir index insertion. + * Call this before modifying the btree so that ENOMEM can be returned + * before any on-disk state has changed. + * + * Returns 0 on success, -ENOMEM on allocation failure. + */ +int btrfs_prealloc_delayed_dir_index(struct btrfs_inode *dir, + const char *name, int name_len, + struct btrfs_dir_index_prealloc *prealloc) +{ + struct btrfs_delayed_node *node; + struct btrfs_delayed_item *item; + + node = btrfs_get_or_create_delayed_node(dir, &prealloc->tracker); + if (IS_ERR(node)) + return PTR_ERR(node); + + item = btrfs_alloc_delayed_item(sizeof(struct btrfs_dir_item) + name_len, + node, BTRFS_DELAYED_INSERTION_ITEM); + if (!item) { + btrfs_release_delayed_node(node, &prealloc->tracker); + return -ENOMEM; + } + + prealloc->node = node; + prealloc->item = item; + return 0; +} + +/* + * Free resources from btrfs_prealloc_delayed_dir_index() when the btree + * insertion failed and we will not commit the delayed dir index. + */ +void btrfs_free_delayed_dir_index_prealloc(struct btrfs_trans_handle *trans, + struct btrfs_dir_index_prealloc *prealloc) { + btrfs_release_delayed_item(prealloc->item); + btrfs_release_dir_index_item_space(trans); + btrfs_release_delayed_node(prealloc->node, &prealloc->tracker); +} + +/* + * Commit a pre-allocated delayed dir index item. The delayed node and item + * must have been returned by btrfs_prealloc_delayed_dir_index(). This + * populates the item, adds it to the delayed node's rb-tree, and reserves + * metadata space. It cannot fail with ENOMEM. + * + * Will return 0 or -EEXIST (index number collision, unexpected). + */ +int btrfs_insert_delayed_dir_index_prealloc(struct btrfs_trans_handle *trans, + struct btrfs_inode *dir, + struct btrfs_dir_index_prealloc *prealloc, + const struct btrfs_disk_key *disk_key, + u8 flags, u64 index) +{ + struct btrfs_delayed_node *delayed_node = prealloc->node; + struct btrfs_ref_tracker *tracker = &prealloc->tracker; + struct btrfs_delayed_item *delayed_item = prealloc->item; struct btrfs_fs_info *fs_info = trans->fs_info; const unsigned int leaf_data_size = BTRFS_LEAF_DATA_SIZE(fs_info); - struct btrfs_delayed_node *delayed_node; - struct btrfs_ref_tracker delayed_node_tracker; - struct btrfs_delayed_item *delayed_item; + const int name_len = delayed_item->data_len - sizeof(struct btrfs_dir_item); struct btrfs_dir_item *dir_item; bool reserve_leaf_space; u32 data_len; int ret; - delayed_node = btrfs_get_or_create_delayed_node(dir, &delayed_node_tracker); - if (IS_ERR(delayed_node)) - return PTR_ERR(delayed_node); - - delayed_item = btrfs_alloc_delayed_item(sizeof(*dir_item) + name_len, - delayed_node, - BTRFS_DELAYED_INSERTION_ITEM); - if (!delayed_item) { - ret = -ENOMEM; - goto release_node; - } - delayed_item->index = index; dir_item = (struct btrfs_dir_item *)delayed_item->data; @@ -1506,7 +1544,7 @@ int btrfs_insert_delayed_dir_index(struct btrfs_trans_handle *trans, btrfs_set_stack_dir_data_len(dir_item, 0); btrfs_set_stack_dir_name_len(dir_item, name_len); btrfs_set_stack_dir_flags(dir_item, flags); - memcpy((char *)(dir_item + 1), name, name_len); + /* Name was already copied into delayed_item->data by the caller. */ data_len = delayed_item->data_len + sizeof(struct btrfs_item); @@ -1524,7 +1562,9 @@ int btrfs_insert_delayed_dir_index(struct btrfs_trans_handle *trans, if (unlikely(ret)) { btrfs_err(trans->fs_info, "error adding delayed dir index item, name: %.*s, index: %llu, root: %llu, dir: %llu, dir->index_cnt: %llu, delayed_node->index_cnt: %llu, error: %d", - name_len, name, index, btrfs_root_id(delayed_node->root), + name_len, + (const char *)(dir_item + 1), + index, btrfs_root_id(delayed_node->root), delayed_node->inode_id, dir->index_cnt, delayed_node->index_cnt, ret); btrfs_release_delayed_item(delayed_item); @@ -1562,10 +1602,31 @@ int btrfs_insert_delayed_dir_index(struct btrfs_trans_handle *trans, mutex_unlock(&delayed_node->mutex); release_node: - btrfs_release_delayed_node(delayed_node, &delayed_node_tracker); + btrfs_release_delayed_node(delayed_node, tracker); return ret; } +/* Will return 0, -ENOMEM or -EEXIST (index number collision, unexpected). */ +int btrfs_insert_delayed_dir_index(struct btrfs_trans_handle *trans, + const char *name, int name_len, + struct btrfs_inode *dir, + const struct btrfs_disk_key *disk_key, u8 flags, + u64 index) +{ + struct btrfs_dir_index_prealloc prealloc; + int ret; + + ret = btrfs_prealloc_delayed_dir_index(dir, name, name_len, &prealloc); + if (ret) + return ret; + + memcpy(prealloc.item->data + sizeof(struct btrfs_dir_item), name, + name_len); + + return btrfs_insert_delayed_dir_index_prealloc(trans, dir, &prealloc, + disk_key, flags, index); +} + static bool btrfs_delete_delayed_insertion_item(struct btrfs_delayed_node *node, u64 index) { diff --git a/fs/btrfs/delayed-inode.h b/fs/btrfs/delayed-inode.h index fc752863f89b..e310a257c9a6 100644 --- a/fs/btrfs/delayed-inode.h +++ b/fs/btrfs/delayed-inode.h @@ -121,6 +121,23 @@ int btrfs_insert_delayed_dir_index(struct btrfs_trans_handle *trans, const struct btrfs_disk_key *disk_key, u8 flags, u64 index); +struct btrfs_dir_index_prealloc { + struct btrfs_delayed_node *node; + struct btrfs_ref_tracker tracker; + struct btrfs_delayed_item *item; +}; + +int btrfs_prealloc_delayed_dir_index(struct btrfs_inode *dir, + const char *name, int name_len, + struct btrfs_dir_index_prealloc *prealloc); +void btrfs_free_delayed_dir_index_prealloc(struct btrfs_trans_handle *trans, + struct btrfs_dir_index_prealloc *prealloc); +int btrfs_insert_delayed_dir_index_prealloc(struct btrfs_trans_handle *trans, + struct btrfs_inode *dir, + struct btrfs_dir_index_prealloc *prealloc, + const struct btrfs_disk_key *disk_key, + u8 flags, u64 index); + int btrfs_delete_delayed_dir_index(struct btrfs_trans_handle *trans, struct btrfs_inode *dir, u64 index); -- 2.55.0