From patchwork Mon Mar 30 16:48:42 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: =?utf-8?q?Marek_Beh=C3=BAn?= X-Patchwork-Id: 244558 List-Id: U-Boot discussion From: marek.behun at nic.cz (=?UTF-8?q?Marek=20Beh=C3=BAn?=) Date: Mon, 30 Mar 2020 18:48:42 +0200 Subject: [PATCH v2] fs: btrfs: support sparse extents Message-ID: <20200330164842.12391-1-marek.behun@nic.cz> When logical address of a regular extent is 0, the extent is sparse and consists of all zeros. Without this when sparse extents are used in a file reading fails with Cannot map logical address 0 to physical Signed-off-by: Marek Beh?n --- fs/btrfs/extent-io.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/fs/btrfs/extent-io.c b/fs/btrfs/extent-io.c index 66d0e1c7d6..2e4599cf64 100644 --- a/fs/btrfs/extent-io.c +++ b/fs/btrfs/extent-io.c @@ -78,6 +78,12 @@ u64 btrfs_read_extent_reg(struct btrfs_path *path, if (size > dlen - offset) size = dlen - offset; + /* sparse extent */ + if (extent->disk_bytenr == 0) { + memset(out, 0, size); + return size; + } + physical = btrfs_map_logical_to_physical(extent->disk_bytenr); if (physical == -1ULL) return -1ULL;