[BUG]
When btrfs-check is executed on even newly created fs, it can report
tree blocks crossing 64K page boundary like this:
Opening filesystem to check...
Checking filesystem on /dev/test/test
UUID: 80d734c8-dcbc-411b-9623-a10bd9e7767f
[1/7] checking root items
[2/7] checking extents
WARNING: tree block [30523392, 30539776) crosses 64K page boudnary, may cause
problem for 64K page system
[3/7] checking free space cache
[4/7] checking fs roots
[5/7] checking only csums items (without verifying data)
[6/7] checking root refs
[7/7] checking quota groups skipped (not enabled on this FS)
found 131072 bytes used, no error found
total csum bytes: 0
total tree bytes: 131072
total fs tree bytes: 32768
total extent tree bytes: 16384
btree space waste bytes: 125199
file data blocks allocated: 0
referenced 0
[CAUSE]
Tree block [30523392, 30539776) is at the last 16K slot of page.
As 30523392 % 65536 = 49152, and 30539776 % 65536 = 0.
The cross boundary check is using exclusive end, which causes false
alerts.
[FIX]
Use inclusive end to do the cross 64K boundary check.
Reported-by: Wang Yugui <wangyu...@e16-tech.com>
Fixes: fc38ae7f4826 ("btrfs-progs: check: detect and warn about tree blocks
crossing 64K page boundary")
Signed-off-by: Qu Wenruo <w...@suse.com>
---
check/mode-common.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/check/mode-common.h b/check/mode-common.h
index 8fdeb7f6be0a..3107b00c48bf 100644
--- a/check/mode-common.h
+++ b/check/mode-common.h
@@ -186,7 +186,7 @@ int get_extent_item_generation(u64 bytenr, u64 *gen_ret);
static inline void btrfs_check_subpage_eb_alignment(u64 start, u32 len)
{
if (start / BTRFS_MAX_METADATA_BLOCKSIZE !=
- (start + len) / BTRFS_MAX_METADATA_BLOCKSIZE)
+ (start + len - 1) / BTRFS_MAX_METADATA_BLOCKSIZE)
warning(
"tree block [%llu, %llu) crosses 64K page boudnary, may cause problem for 64K
page system",
start, start + len);
--
2.30.1
