Commit a9b2e0de authored by Omar Sandoval's avatar Omar Sandoval Committed by David Sterba
Browse files

btrfs: send: get rid of i_size logic in send_write() 



send_write()/fill_read_buf() have some logic for avoiding reading past
i_size. However, everywhere that we call
send_write()/send_extent_data(), we've already clamped the length down
to i_size. Get rid of the i_size handling, which simplifies the next
change.

Reviewed-by: default avatarFilipe Manana <fdmanana@suse.com>
Reviewed-by: default avatarJosef Bacik <josef@toxicpanda.com>
Signed-off-by: default avatarOmar Sandoval <osandov@fb.com>
Signed-off-by: default avatarDavid Sterba <dsterba@suse.com>
parent 0cbb5bdf

fs/btrfs/send.c

+10 −27
Original line number Diff line number Diff line
@@ -4794,7 +4794,7 @@ static int process_all_new_xattrs(struct send_ctx *sctx) 
	return ret;

}



static ssize_t fill_read_buf(struct send_ctx *sctx, u64 offset, u32 len)

static int fill_read_buf(struct send_ctx *sctx, u64 offset, u32 len)

{

	struct btrfs_root *root = sctx->send_root;

	struct btrfs_fs_info *fs_info = root->fs_info;
@@ -4804,21 +4804,13 @@ static ssize_t fill_read_buf(struct send_ctx *sctx, u64 offset, u32 len) 
	pgoff_t index = offset >> PAGE_SHIFT;

	pgoff_t last_index;

	unsigned pg_offset = offset_in_page(offset);

	ssize_t ret = 0;

	int ret = 0;

	size_t read = 0;



	inode = btrfs_iget(fs_info->sb, sctx->cur_ino, root);

	if (IS_ERR(inode))

		return PTR_ERR(inode);



	if (offset + len > i_size_read(inode)) {

		if (offset > i_size_read(inode))

			len = 0;

		else

			len = offset - i_size_read(inode);

	}

	if (len == 0)

		goto out;



	last_index = (offset + len - 1) >> PAGE_SHIFT;



	/* initial readahead */
@@ -4859,16 +4851,15 @@ static ssize_t fill_read_buf(struct send_ctx *sctx, u64 offset, u32 len) 
		}



		addr = kmap(page);

		memcpy(sctx->read_buf + ret, addr + pg_offset, cur_len);

		memcpy(sctx->read_buf + read, addr + pg_offset, cur_len);

		kunmap(page);

		unlock_page(page);

		put_page(page);

		index++;

		pg_offset = 0;

		len -= cur_len;

		ret += cur_len;

		read += cur_len;

	}

out:

	iput(inode);

	return ret;

}
@@ -4882,7 +4873,6 @@ static int send_write(struct send_ctx *sctx, u64 offset, u32 len) 
	struct btrfs_fs_info *fs_info = sctx->send_root->fs_info;

	int ret = 0;

	struct fs_path *p;

	ssize_t num_read = 0;



	p = fs_path_alloc();

	if (!p)
@@ -4890,12 +4880,9 @@ static int send_write(struct send_ctx *sctx, u64 offset, u32 len) 


	btrfs_debug(fs_info, "send_write offset=%llu, len=%d", offset, len);



	num_read = fill_read_buf(sctx, offset, len);

	if (num_read <= 0) {

		if (num_read < 0)

			ret = num_read;

	ret = fill_read_buf(sctx, offset, len);

	if (ret < 0)

		goto out;

	}



	ret = begin_cmd(sctx, BTRFS_SEND_C_WRITE);

	if (ret < 0)
@@ -4907,16 +4894,14 @@ static int send_write(struct send_ctx *sctx, u64 offset, u32 len) 


	TLV_PUT_PATH(sctx, BTRFS_SEND_A_PATH, p);

	TLV_PUT_U64(sctx, BTRFS_SEND_A_FILE_OFFSET, offset);

	TLV_PUT(sctx, BTRFS_SEND_A_DATA, sctx->read_buf, num_read);

	TLV_PUT(sctx, BTRFS_SEND_A_DATA, sctx->read_buf, len);



	ret = send_cmd(sctx);



tlv_put_failure:

out:

	fs_path_free(p);

	if (ret < 0)

	return ret;

	return num_read;

}



/*
@@ -5095,9 +5080,7 @@ static int send_extent_data(struct send_ctx *sctx, 
		ret = send_write(sctx, offset + sent, size);

		if (ret < 0)

			return ret;

		if (!ret)

			break;

		sent += ret;

		sent += size;

	}

	return 0;

}