From 7ca4be45a0255ac8f08c05491c6add2dd87dd4f8 Mon Sep 17 00:00:00 2001 From: Chris Mason Date: Tue, 31 Jan 2012 20:19:02 -0500 Subject: [PATCH] Btrfs: don't use crc items bigger than 4KB With the big metadata blocks, we can have crc items that are much bigger than a page. There are a few places that we try to kmalloc memory to hold the items during a split. Items bigger than 4KB don't really have a huge benefit in efficiency, but they do trigger larger order allocations. This commits changes the csums to make sure they stay under 4KB. This is not a format change, just a #define to limit huge items. Signed-off-by: Chris Mason --- fs/btrfs/file-item.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/fs/btrfs/file-item.c b/fs/btrfs/file-item.c index a14dbca..cab0ffb 100644 --- a/fs/btrfs/file-item.c +++ b/fs/btrfs/file-item.c @@ -25,10 +25,12 @@ #include "transaction.h" #include "print-tree.h" -#define MAX_CSUM_ITEMS(r, size) ((((BTRFS_LEAF_DATA_SIZE(r) - \ +#define __MAX_CSUM_ITEMS(r, size) ((((BTRFS_LEAF_DATA_SIZE(r) - \ sizeof(struct btrfs_item) * 2) / \ size) - 1)) +#define MAX_CSUM_ITEMS(r, size) (min(__MAX_CSUM_ITEMS(r, size), PAGE_CACHE_SIZE)) + #define MAX_ORDERED_SUM_BYTES(r) ((PAGE_SIZE - \ sizeof(struct btrfs_ordered_sum)) / \ sizeof(struct btrfs_sector_sum) * \ -- 2.7.4