From c6aeae86b9af577ae84b97e6affcb228f5b9481a Mon Sep 17 00:00:00 2001 From: David Sterba Date: Wed, 4 Jun 2025 11:29:27 +0200 Subject: [PATCH] btrfs: use on-stack variable for block reserve in btrfs_replace_file_extents() We can avoid potential memory allocation failure in btrfs_replace_file_extents() as the block reserve lifetime is limited to the scope of the function. This requires +48 bytes on stack. Signed-off-by: David Sterba --- fs/btrfs/file.c | 29 ++++++++++++----------------- 1 file changed, 12 insertions(+), 17 deletions(-) diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c index 8ce6f45f45e0..2902de88dd1b 100644 --- a/fs/btrfs/file.c +++ b/fs/btrfs/file.c @@ -2341,7 +2341,7 @@ int btrfs_replace_file_extents(struct btrfs_inode *inode, u64 min_size = btrfs_calc_insert_metadata_size(fs_info, 1); u64 ino_size = round_up(inode->vfs_inode.i_size, fs_info->sectorsize); struct btrfs_trans_handle *trans = NULL; - struct btrfs_block_rsv *rsv; + struct btrfs_block_rsv rsv; unsigned int rsv_count; u64 cur_offset; u64 len = end - start; @@ -2350,13 +2350,9 @@ int btrfs_replace_file_extents(struct btrfs_inode *inode, if (end <= start) return -EINVAL; - rsv = btrfs_alloc_block_rsv(fs_info, BTRFS_BLOCK_RSV_TEMP); - if (!rsv) { - ret = -ENOMEM; - goto out; - } - rsv->size = btrfs_calc_insert_metadata_size(fs_info, 1); - rsv->failfast = true; + btrfs_init_metadata_block_rsv(fs_info, &rsv, BTRFS_BLOCK_RSV_TEMP); + rsv.size = btrfs_calc_insert_metadata_size(fs_info, 1); + rsv.failfast = true; /* * 1 - update the inode @@ -2373,14 +2369,14 @@ int btrfs_replace_file_extents(struct btrfs_inode *inode, if (IS_ERR(trans)) { ret = PTR_ERR(trans); trans = NULL; - goto out_free; + goto out_release; } - ret = btrfs_block_rsv_migrate(&fs_info->trans_block_rsv, rsv, + ret = btrfs_block_rsv_migrate(&fs_info->trans_block_rsv, &rsv, min_size, false); if (WARN_ON(ret)) goto out_trans; - trans->block_rsv = rsv; + trans->block_rsv = &rsv; cur_offset = start; drop_args.path = path; @@ -2496,10 +2492,10 @@ int btrfs_replace_file_extents(struct btrfs_inode *inode, } ret = btrfs_block_rsv_migrate(&fs_info->trans_block_rsv, - rsv, min_size, false); + &rsv, min_size, false); if (WARN_ON(ret)) break; - trans->block_rsv = rsv; + trans->block_rsv = &rsv; cur_offset = drop_args.drop_end; len = end - cur_offset; @@ -2576,16 +2572,15 @@ int btrfs_replace_file_extents(struct btrfs_inode *inode, out_trans: if (!trans) - goto out_free; + goto out_release; trans->block_rsv = &fs_info->trans_block_rsv; if (ret) btrfs_end_transaction(trans); else *trans_out = trans; -out_free: - btrfs_free_block_rsv(fs_info, rsv); -out: +out_release: + btrfs_block_rsv_release(fs_info, &rsv, (u64)-1, NULL); return ret; } -- 2.25.1