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authorOmar Sandoval <osandov@fb.com>2016-07-15 12:12:48 -0700
committerDavid Sterba <dsterba@suse.com>2016-07-26 18:35:05 +0200
commit1d6c7cb725bb7d25981d44915b316e24751b7b72 (patch)
tree7199982cc55d2a8631191bcd98ac9cbabd54f3b9 /extent_io.h
parent029772be1152bbdf921ee74b95cfcde4003f5e46 (diff)
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btrfs-progs: fix btrfsck of space_cache=v2 bitmaps on big-endian
Copy le_test_bit() from the kernel and use that for the free space tree bitmaps. Signed-off-by: Omar Sandoval <osandov@fb.com> Signed-off-by: David Sterba <dsterba@suse.com>
Diffstat (limited to 'extent_io.h')
-rw-r--r--extent_io.h19
1 files changed, 19 insertions, 0 deletions
diff --git a/extent_io.h b/extent_io.h
index a9a7353..94a42bf 100644
--- a/extent_io.h
+++ b/extent_io.h
@@ -49,6 +49,25 @@
#define BLOCK_GROUP_DIRTY EXTENT_DIRTY
+/*
+ * The extent buffer bitmap operations are done with byte granularity instead of
+ * word granularity for two reasons:
+ * 1. The bitmaps must be little-endian on disk.
+ * 2. Bitmap items are not guaranteed to be aligned to a word and therefore a
+ * single word in a bitmap may straddle two pages in the extent buffer.
+ */
+#define BIT_BYTE(nr) ((nr) / BITS_PER_BYTE)
+#define BYTE_MASK ((1 << BITS_PER_BYTE) - 1)
+#define BITMAP_FIRST_BYTE_MASK(start) \
+ ((BYTE_MASK << ((start) & (BITS_PER_BYTE - 1))) & BYTE_MASK)
+#define BITMAP_LAST_BYTE_MASK(nbits) \
+ (BYTE_MASK >> (-(nbits) & (BITS_PER_BYTE - 1)))
+
+static inline int le_test_bit(int nr, const u8 *addr)
+{
+ return 1U & (addr[BIT_BYTE(nr)] >> (nr & (BITS_PER_BYTE-1)));
+}
+
struct btrfs_fs_info;
struct extent_io_tree {