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OpenCloudOS-Kernel
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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 <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This commit is contained in:
David Sterba 2018-05-11 17:57:54 +02:00
parent 67b07bd4be
commit bf5091c8d6
1 changed files with 9 additions and 7 deletions
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16
fs/btrfs/ioctl.c
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@ -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;
}