From bd926c63b7a6843d3ce2728396c0891e54fce5c4 Mon Sep 17 00:00:00 2001 From: NeilBrown Date: Tue, 8 Nov 2005 21:39:32 -0800 Subject: [PATCH] [PATCH] md: make md on-disk bitmaps not host-endian Current bitmaps use set_bit et.al and so are host-endian, which means not-portable. Oops. Define a new version number (4) for which bitmaps are little-endian. Signed-off-by: Neil Brown Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/md/bitmap.c | 22 ++++++++++++++++++---- drivers/md/md.c | 2 +- include/linux/raid/bitmap.h | 11 +++++++++-- include/linux/raid/md.h | 4 +++- 4 files changed, 31 insertions(+), 8 deletions(-) diff --git a/drivers/md/bitmap.c b/drivers/md/bitmap.c index c5fa4c2..220273e 100644 --- a/drivers/md/bitmap.c +++ b/drivers/md/bitmap.c @@ -482,7 +482,8 @@ static int bitmap_read_sb(struct bitmap *bitmap) /* verify that the bitmap-specific fields are valid */ if (sb->magic != cpu_to_le32(BITMAP_MAGIC)) reason = "bad magic"; - else if (sb->version != cpu_to_le32(BITMAP_MAJOR)) + else if (le32_to_cpu(sb->version) < BITMAP_MAJOR_LO || + le32_to_cpu(sb->version) > BITMAP_MAJOR_HI) reason = "unrecognized superblock version"; else if (chunksize < 512 || chunksize > (1024 * 1024 * 4)) reason = "bitmap chunksize out of range (512B - 4MB)"; @@ -527,6 +528,8 @@ success: bitmap->daemon_lastrun = jiffies; bitmap->max_write_behind = write_behind; bitmap->flags |= sb->state; + if (le32_to_cpu(sb->version) == BITMAP_MAJOR_HOSTENDIAN) + bitmap->flags |= BITMAP_HOSTENDIAN; bitmap->events_cleared = le64_to_cpu(sb->events_cleared); if (sb->state & BITMAP_STALE) bitmap->events_cleared = bitmap->mddev->events; @@ -764,7 +767,10 @@ static void bitmap_file_set_bit(struct bitmap *bitmap, sector_t block) /* set the bit */ kaddr = kmap_atomic(page, KM_USER0); - set_bit(bit, kaddr); + if (bitmap->flags & BITMAP_HOSTENDIAN) + set_bit(bit, kaddr); + else + ext2_set_bit(bit, kaddr); kunmap_atomic(kaddr, KM_USER0); PRINTK("set file bit %lu page %lu\n", bit, page->index); @@ -891,6 +897,7 @@ static int bitmap_init_from_disk(struct bitmap *bitmap, sector_t start) oldindex = ~0L; for (i = 0; i < chunks; i++) { + int b; index = file_page_index(i); bit = file_page_offset(i); if (index != oldindex) { /* this is a new page, read it in */ @@ -939,7 +946,11 @@ static int bitmap_init_from_disk(struct bitmap *bitmap, sector_t start) bitmap->filemap[bitmap->file_pages++] = page; } - if (test_bit(bit, page_address(page))) { + if (bitmap->flags & BITMAP_HOSTENDIAN) + b = test_bit(bit, page_address(page)); + else + b = ext2_test_bit(bit, page_address(page)); + if (b) { /* if the disk bit is set, set the memory bit */ bitmap_set_memory_bits(bitmap, i << CHUNK_BLOCK_SHIFT(bitmap), ((i+1) << (CHUNK_BLOCK_SHIFT(bitmap)) >= start) @@ -1097,7 +1108,10 @@ int bitmap_daemon_work(struct bitmap *bitmap) -1); /* clear the bit */ - clear_bit(file_page_offset(j), page_address(page)); + if (bitmap->flags & BITMAP_HOSTENDIAN) + clear_bit(file_page_offset(j), page_address(page)); + else + ext2_clear_bit(file_page_offset(j), page_address(page)); } } spin_unlock_irqrestore(&bitmap->lock, flags); diff --git a/drivers/md/md.c b/drivers/md/md.c index 9dfa063..caa4add 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -4281,7 +4281,7 @@ static int __init md_init(void) " MD_SB_DISKS=%d\n", MD_MAJOR_VERSION, MD_MINOR_VERSION, MD_PATCHLEVEL_VERSION, MAX_MD_DEVS, MD_SB_DISKS); - printk(KERN_INFO "md: bitmap version %d.%d\n", BITMAP_MAJOR, + printk(KERN_INFO "md: bitmap version %d.%d\n", BITMAP_MAJOR_HI, BITMAP_MINOR); if (register_blkdev(MAJOR_NR, "md")) diff --git a/include/linux/raid/bitmap.h b/include/linux/raid/bitmap.h index 9de9919..8994378 100644 --- a/include/linux/raid/bitmap.h +++ b/include/linux/raid/bitmap.h @@ -6,7 +6,13 @@ #ifndef BITMAP_H #define BITMAP_H 1 -#define BITMAP_MAJOR 3 +#define BITMAP_MAJOR_LO 3 +/* version 4 insists the bitmap is in little-endian order + * with version 3, it is host-endian which is non-portable + */ +#define BITMAP_MAJOR_HI 4 +#define BITMAP_MAJOR_HOSTENDIAN 3 + #define BITMAP_MINOR 39 /* @@ -133,7 +139,8 @@ typedef __u16 bitmap_counter_t; /* use these for bitmap->flags and bitmap->sb->state bit-fields */ enum bitmap_state { BITMAP_ACTIVE = 0x001, /* the bitmap is in use */ - BITMAP_STALE = 0x002 /* the bitmap file is out of date or had -EIO */ + BITMAP_STALE = 0x002, /* the bitmap file is out of date or had -EIO */ + BITMAP_HOSTENDIAN = 0x8000, }; /* the superblock at the front of the bitmap file -- little endian */ diff --git a/include/linux/raid/md.h b/include/linux/raid/md.h index ffa316c..91467a3 100644 --- a/include/linux/raid/md.h +++ b/include/linux/raid/md.h @@ -66,8 +66,10 @@ * and major_version/minor_version accordingly * >=2 means that Internal bitmaps are supported by setting MD_SB_BITMAP_PRESENT * in the super status byte + * >=3 means that bitmap superblock version 4 is supported, which uses + * little-ending representation rather than host-endian */ -#define MD_PATCHLEVEL_VERSION 2 +#define MD_PATCHLEVEL_VERSION 3 extern int register_md_personality (int p_num, mdk_personality_t *p); extern int unregister_md_personality (int p_num); -- 2.7.4