Btrfs: don't allocate dip->csums when doing writes (98bc3149) · Commits · 戴 / test

When doing direct writes we store the checksums in the ordered sum stuff in the ordered extent for writing them when the write completes, so we don't even use the dip->csums array. So if we're writing, don't bother allocating dip->csums since we won't use it anyway. Thanks, Signed-off-by:

Josef Bacik <josef@redhat.com>

fs/btrfs/inode.c

+5 −2

Original line number	Diff line number	Diff line
		@@ -5944,6 +5944,7 @@ static int btrfs_submit_direct_hook(int rw, struct btrfs_dio_private *dip,
		int nr_pages = 0;
		u32 *csums = dip->csums;
		int ret = 0;
		int write = rw & REQ_WRITE;

		bio = btrfs_dio_bio_alloc(orig_bio->bi_bdev, start_sector, GFP_NOFS);
		if (!bio)
		@@ -5980,7 +5981,8 @@ static int btrfs_submit_direct_hook(int rw, struct btrfs_dio_private *dip,
		goto out_err;
		}

		if (!skip_sum)
		/* Write's use the ordered csums */
		if (!write && !skip_sum)
		csums = csums + nr_pages;
		start_sector += submit_len >> 9;
		file_offset += submit_len;
		@@ -6048,7 +6050,8 @@ static void btrfs_submit_direct(int rw, struct bio bio, struct inode inode,
		}
		dip->csums = NULL;

		if (!skip_sum) {
		/* Write's use the ordered csum stuff, so we don't need dip->csums */
		if (!write && !skip_sum) {
		dip->csums = kmalloc(sizeof(u32) * bio->bi_vcnt, GFP_NOFS);
		if (!dip->csums) {
		kfree(dip);

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