From bf5091c8d69e95c34dab2224b98a9cb0ccff1aa8 Mon Sep 17 00:00:00 2001 From: David Sterba Date: Fri, 11 May 2018 17:57:54 +0200 Subject: [PATCH] btrfs: use kvzalloc for EXTENT_SAME temporary data The dedupe range is 16 MiB, with 4 KiB pages and 8 byte pointers, the arrays can be 32KiB large. To avoid allocation failures due to fragmented memory, use the allocation with fallback to vmalloc. The arrays are allocated and freed only inside btrfs_extent_same and reused for all the ranges. Reviewed-by: Nikolay Borisov Signed-off-by: David Sterba --- fs/btrfs/ioctl.c | 16 +++++++++------- 1 file changed, 9 insertions(+), 7 deletions(-) diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c index 99eab7b3..aeef6cd 100644 --- a/fs/btrfs/ioctl.c +++ b/fs/btrfs/ioctl.c @@ -3144,12 +3144,13 @@ static int btrfs_extent_same(struct inode *src, u64 loff, u64 olen, * locking. We use an array for the page pointers. Size of the array is * bounded by len, which is in turn bounded by BTRFS_MAX_DEDUPE_LEN. */ - cmp.src_pages = kcalloc(num_pages, sizeof(struct page *), GFP_KERNEL); - cmp.dst_pages = kcalloc(num_pages, sizeof(struct page *), GFP_KERNEL); + cmp.src_pages = kvmalloc_array(num_pages, sizeof(struct page *), + GFP_KERNEL | __GFP_ZERO); + cmp.dst_pages = kvmalloc_array(num_pages, sizeof(struct page *), + GFP_KERNEL | __GFP_ZERO); if (!cmp.src_pages || !cmp.dst_pages) { - kfree(cmp.src_pages); - kfree(cmp.dst_pages); - return -ENOMEM; + ret = -ENOMEM; + goto out_free; } for (i = 0; i < chunk_count; i++) { @@ -3172,8 +3173,9 @@ out_unlock: else btrfs_double_inode_unlock(src, dst); - kfree(cmp.src_pages); - kfree(cmp.dst_pages); +out_free: + kvfree(cmp.src_pages); + kvfree(cmp.dst_pages); return ret; } -- 2.7.4