From a26a6bedafcf3ddacb90ec4353306c2f8a5e36dc Mon Sep 17 00:00:00 2001 From: Qu Wenruo Date: Wed, 24 Jun 2020 18:03:09 +0200 Subject: fs: btrfs: Introduce btrfs_read_extent_inline() and btrfs_read_extent_reg() MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit These two functions are used to do sector aligned read, which will be later used to implement btrfs_file_read(). Signed-off-by: Qu Wenruo Reviewed-by: Marek Behún --- fs/btrfs/disk-io.c | 36 ++++++++++++++++++++++++++++++++++++ 1 file changed, 36 insertions(+) (limited to 'fs/btrfs/disk-io.c') diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c index 4d08b0204a..4da1b80038 100644 --- a/fs/btrfs/disk-io.c +++ b/fs/btrfs/disk-io.c @@ -565,6 +565,42 @@ struct extent_buffer* read_tree_block(struct btrfs_fs_info *fs_info, u64 bytenr, return ERR_PTR(ret); } +int read_extent_data(struct btrfs_fs_info *fs_info, char *data, u64 logical, + u64 *len, int mirror) +{ + u64 offset = 0; + struct btrfs_multi_bio *multi = NULL; + struct btrfs_device *device; + int ret = 0; + u64 max_len = *len; + + ret = btrfs_map_block(fs_info, READ, logical, len, &multi, mirror, + NULL); + if (ret) { + fprintf(stderr, "Couldn't map the block %llu\n", + logical + offset); + goto err; + } + device = multi->stripes[0].dev; + + if (*len > max_len) + *len = max_len; + if (!device->desc || !device->part) { + ret = -EIO; + goto err; + } + + ret = __btrfs_devread(device->desc, device->part, data, *len, + multi->stripes[0].physical); + if (ret != *len) + ret = -EIO; + else + ret = 0; +err: + kfree(multi); + return ret; +} + void btrfs_setup_root(struct btrfs_root *root, struct btrfs_fs_info *fs_info, u64 objectid) { -- cgit v1.2.3