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* [PATCH] fs: btrfs: support sparse extents
@ 2020-03-30 16:41 Marek Behún
  2020-03-30 17:06 ` Marek Behun
  0 siblings, 1 reply; 2+ messages in thread
From: Marek Behún @ 2020-03-30 16:41 UTC (permalink / raw)
  To: u-boot

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 <marek.behun@nic.cz>
---
 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..53899bf79a 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, dlen);
+		return dlen;
+	}
+
 	physical = btrfs_map_logical_to_physical(extent->disk_bytenr);
 	if (physical == -1ULL)
 		return -1ULL;
-- 
2.24.1

^ permalink raw reply related	[flat|nested] 2+ messages in thread

* [PATCH] fs: btrfs: support sparse extents
  2020-03-30 16:41 [PATCH] fs: btrfs: support sparse extents Marek Behún
@ 2020-03-30 17:06 ` Marek Behun
  0 siblings, 0 replies; 2+ messages in thread
From: Marek Behun @ 2020-03-30 17:06 UTC (permalink / raw)
  To: u-boot

Sorry, dont apply this. I've sent v2.
Marek

^ permalink raw reply	[flat|nested] 2+ messages in thread

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