Commit a654b9d8 authored by NeilBrown's avatar NeilBrown Committed by Linus Torvalds

[PATCH] md: allow md intent bitmap to be stored near the superblock.

This provides an alternate to storing the bitmap in a separate file.  The
bitmap can be stored at a given offset from the superblock.  Obviously the
creator of the array must make sure this doesn't intersect with data....
After is good for version-0.90 superblocks.
Signed-off-by: default avatarNeil Brown <neilb@cse.unsw.edu.au>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 3d310eb7
......@@ -116,7 +116,7 @@ static unsigned char *bitmap_alloc_page(struct bitmap *bitmap)
if (!page)
printk("%s: bitmap_alloc_page FAILED\n", bmname(bitmap));
else
printk("%s: bitmap_alloc_page: allocated page at %p\n",
PRINTK("%s: bitmap_alloc_page: allocated page at %p\n",
bmname(bitmap), page);
return page;
}
......@@ -258,13 +258,61 @@ char *file_path(struct file *file, char *buf, int count)
* basic page I/O operations
*/
/* IO operations when bitmap is stored near all superblocks */
static struct page *read_sb_page(mddev_t *mddev, long offset, unsigned long index)
{
/* choose a good rdev and read the page from there */
mdk_rdev_t *rdev;
struct list_head *tmp;
struct page *page = alloc_page(GFP_KERNEL);
sector_t target;
if (!page)
return ERR_PTR(-ENOMEM);
do {
ITERATE_RDEV(mddev, rdev, tmp)
if (rdev->in_sync && !rdev->faulty)
goto found;
return ERR_PTR(-EIO);
found:
target = (rdev->sb_offset << 1) + offset + index * (PAGE_SIZE/512);
} while (!sync_page_io(rdev->bdev, target, PAGE_SIZE, page, READ));
page->index = index;
return page;
}
static int write_sb_page(mddev_t *mddev, long offset, struct page *page, int wait)
{
mdk_rdev_t *rdev;
struct list_head *tmp;
ITERATE_RDEV(mddev, rdev, tmp)
if (rdev->in_sync && !rdev->faulty)
md_super_write(mddev, rdev,
(rdev->sb_offset<<1) + offset
+ page->index * (PAGE_SIZE/512),
PAGE_SIZE,
page);
if (wait)
wait_event(mddev->sb_wait, atomic_read(&mddev->pending_writes)==0);
return 0;
}
/*
* write out a page
* write out a page to a file
*/
static int write_page(struct bitmap *bitmap, struct page *page, int wait)
{
int ret = -ENOMEM;
if (bitmap->file == NULL)
return write_sb_page(bitmap->mddev, bitmap->offset, page, wait);
lock_page(page);
ret = page->mapping->a_ops->prepare_write(NULL, page, 0, PAGE_SIZE);
......@@ -394,7 +442,12 @@ static int bitmap_read_sb(struct bitmap *bitmap)
int err = -EINVAL;
/* page 0 is the superblock, read it... */
bitmap->sb_page = read_page(bitmap->file, 0, &bytes_read);
if (bitmap->file)
bitmap->sb_page = read_page(bitmap->file, 0, &bytes_read);
else {
bitmap->sb_page = read_sb_page(bitmap->mddev, bitmap->offset, 0);
bytes_read = PAGE_SIZE;
}
if (IS_ERR(bitmap->sb_page)) {
err = PTR_ERR(bitmap->sb_page);
bitmap->sb_page = NULL;
......@@ -625,14 +678,16 @@ static void bitmap_file_kick(struct bitmap *bitmap)
bitmap_mask_state(bitmap, BITMAP_STALE, MASK_SET);
bitmap_update_sb(bitmap);
path = kmalloc(PAGE_SIZE, GFP_KERNEL);
if (path)
ptr = file_path(bitmap->file, path, PAGE_SIZE);
if (bitmap->file) {
path = kmalloc(PAGE_SIZE, GFP_KERNEL);
if (path)
ptr = file_path(bitmap->file, path, PAGE_SIZE);
printk(KERN_ALERT "%s: kicking failed bitmap file %s from array!\n",
bmname(bitmap), ptr ? ptr : "");
printk(KERN_ALERT "%s: kicking failed bitmap file %s from array!\n",
bmname(bitmap), ptr ? ptr : "");
kfree(path);
kfree(path);
}
bitmap_file_put(bitmap);
......@@ -676,7 +731,7 @@ static void bitmap_file_set_bit(struct bitmap *bitmap, sector_t block)
void *kaddr;
unsigned long chunk = block >> CHUNK_BLOCK_SHIFT(bitmap);
if (!bitmap->file || !bitmap->filemap) {
if (!bitmap->filemap) {
return;
}
......@@ -715,7 +770,7 @@ int bitmap_unplug(struct bitmap *bitmap)
* flushed out to disk */
for (i = 0; i < bitmap->file_pages; i++) {
spin_lock_irqsave(&bitmap->lock, flags);
if (!bitmap->file || !bitmap->filemap) {
if (!bitmap->filemap) {
spin_unlock_irqrestore(&bitmap->lock, flags);
return 0;
}
......@@ -732,11 +787,15 @@ int bitmap_unplug(struct bitmap *bitmap)
return 1;
}
if (wait) { /* if any writes were performed, we need to wait on them */
spin_lock_irq(&bitmap->write_lock);
wait_event_lock_irq(bitmap->write_wait,
list_empty(&bitmap->complete_pages), bitmap->write_lock,
wake_up_process(bitmap->writeback_daemon->tsk));
spin_unlock_irq(&bitmap->write_lock);
if (bitmap->file) {
spin_lock_irq(&bitmap->write_lock);
wait_event_lock_irq(bitmap->write_wait,
list_empty(&bitmap->complete_pages), bitmap->write_lock,
wake_up_process(bitmap->writeback_daemon->tsk));
spin_unlock_irq(&bitmap->write_lock);
} else
wait_event(bitmap->mddev->sb_wait,
atomic_read(&bitmap->mddev->pending_writes)==0);
}
return 0;
}
......@@ -764,7 +823,7 @@ static int bitmap_init_from_disk(struct bitmap *bitmap, int in_sync)
chunks = bitmap->chunks;
file = bitmap->file;
BUG_ON(!file);
BUG_ON(!file && !bitmap->offset);
#if INJECT_FAULTS_3
outofdate = 1;
......@@ -779,7 +838,7 @@ static int bitmap_init_from_disk(struct bitmap *bitmap, int in_sync)
num_pages = (bytes + sizeof(bitmap_super_t) + PAGE_SIZE - 1) / PAGE_SIZE;
if (i_size_read(file->f_mapping->host) < bytes + sizeof(bitmap_super_t)) {
if (file && i_size_read(file->f_mapping->host) < bytes + sizeof(bitmap_super_t)) {
printk(KERN_INFO "%s: bitmap file too short %lu < %lu\n",
bmname(bitmap),
(unsigned long) i_size_read(file->f_mapping->host),
......@@ -816,14 +875,18 @@ static int bitmap_init_from_disk(struct bitmap *bitmap, int in_sync)
*/
page = bitmap->sb_page;
offset = sizeof(bitmap_super_t);
} else {
} else if (file) {
page = read_page(file, index, &dummy);
if (IS_ERR(page)) { /* read error */
ret = PTR_ERR(page);
goto out;
}
offset = 0;
} else {
page = read_sb_page(bitmap->mddev, bitmap->offset, index);
offset = 0;
}
if (IS_ERR(page)) { /* read error */
ret = PTR_ERR(page);
goto out;
}
oldindex = index;
oldpage = page;
kmap(page);
......@@ -874,6 +937,19 @@ static int bitmap_init_from_disk(struct bitmap *bitmap, int in_sync)
return ret;
}
void bitmap_write_all(struct bitmap *bitmap)
{
/* We don't actually write all bitmap blocks here,
* just flag them as needing to be written
*/
unsigned long chunks = bitmap->chunks;
unsigned long bytes = (chunks+7)/8 + sizeof(bitmap_super_t);
unsigned long num_pages = (bytes + PAGE_SIZE-1) / PAGE_SIZE;
while (num_pages--)
bitmap->filemap_attr[num_pages] |= BITMAP_PAGE_NEEDWRITE;
}
static void bitmap_count_page(struct bitmap *bitmap, sector_t offset, int inc)
{
......@@ -913,7 +989,7 @@ int bitmap_daemon_work(struct bitmap *bitmap)
for (j = 0; j < bitmap->chunks; j++) {
bitmap_counter_t *bmc;
spin_lock_irqsave(&bitmap->lock, flags);
if (!bitmap->file || !bitmap->filemap) {
if (!bitmap->filemap) {
/* error or shutdown */
spin_unlock_irqrestore(&bitmap->lock, flags);
break;
......@@ -1072,6 +1148,7 @@ static int bitmap_start_daemon(struct bitmap *bitmap, mdk_thread_t **ptr,
spin_lock_irqsave(&bitmap->lock, flags);
*ptr = NULL;
if (!bitmap->file) /* no need for daemon if there's no backing file */
goto out_unlock;
......@@ -1416,9 +1493,11 @@ int bitmap_create(mddev_t *mddev)
BUG_ON(sizeof(bitmap_super_t) != 256);
if (!file) /* bitmap disabled, nothing to do */
if (!file && !mddev->bitmap_offset) /* bitmap disabled, nothing to do */
return 0;
BUG_ON(file && mddev->bitmap_offset);
bitmap = kmalloc(sizeof(*bitmap), GFP_KERNEL);
if (!bitmap)
return -ENOMEM;
......@@ -1438,7 +1517,8 @@ int bitmap_create(mddev_t *mddev)
return -ENOMEM;
bitmap->file = file;
get_file(file);
bitmap->offset = mddev->bitmap_offset;
if (file) get_file(file);
/* read superblock from bitmap file (this sets bitmap->chunksize) */
err = bitmap_read_sb(bitmap);
if (err)
......
......@@ -337,7 +337,7 @@ static int bi_complete(struct bio *bio, unsigned int bytes_done, int error)
return 0;
}
static int sync_page_io(struct block_device *bdev, sector_t sector, int size,
int sync_page_io(struct block_device *bdev, sector_t sector, int size,
struct page *page, int rw)
{
struct bio *bio = bio_alloc(GFP_NOIO, 1);
......@@ -609,6 +609,17 @@ static int super_90_validate(mddev_t *mddev, mdk_rdev_t *rdev)
memcpy(mddev->uuid+12,&sb->set_uuid3, 4);
mddev->max_disks = MD_SB_DISKS;
if (sb->state & (1<<MD_SB_BITMAP_PRESENT) &&
mddev->bitmap_file == NULL) {
if (mddev->level != 1) {
/* FIXME use a better test */
printk(KERN_WARNING "md: bitmaps only support for raid1\n");
return -EINVAL;
}
mddev->bitmap_offset = (MD_SB_BYTES >> 9);
}
} else if (mddev->pers == NULL) {
/* Insist on good event counter while assembling */
__u64 ev1 = md_event(sb);
......@@ -702,6 +713,9 @@ static void super_90_sync(mddev_t *mddev, mdk_rdev_t *rdev)
sb->layout = mddev->layout;
sb->chunk_size = mddev->chunk_size;
if (mddev->bitmap && mddev->bitmap_file == NULL)
sb->state |= (1<<MD_SB_BITMAP_PRESENT);
sb->disks[0].state = (1<<MD_DISK_REMOVED);
ITERATE_RDEV(mddev,rdev2,tmp) {
mdp_disk_t *d;
......@@ -898,6 +912,15 @@ static int super_1_validate(mddev_t *mddev, mdk_rdev_t *rdev)
memcpy(mddev->uuid, sb->set_uuid, 16);
mddev->max_disks = (4096-256)/2;
if ((le32_to_cpu(sb->feature_map) & 1) &&
mddev->bitmap_file == NULL ) {
if (mddev->level != 1) {
printk(KERN_WARNING "md: bitmaps only supported for raid1\n");
return -EINVAL;
}
mddev->bitmap_offset = (__s32)le32_to_cpu(sb->bitmap_offset);
}
} else if (mddev->pers == NULL) {
/* Insist of good event counter while assembling */
__u64 ev1 = le64_to_cpu(sb->events);
......@@ -960,6 +983,11 @@ static void super_1_sync(mddev_t *mddev, mdk_rdev_t *rdev)
else
sb->resync_offset = cpu_to_le64(0);
if (mddev->bitmap && mddev->bitmap_file == NULL) {
sb->bitmap_offset = cpu_to_le32((__u32)mddev->bitmap_offset);
sb->feature_map = cpu_to_le32(1);
}
max_dev = 0;
ITERATE_RDEV(mddev,rdev2,tmp)
if (rdev2->desc_nr+1 > max_dev)
......@@ -2406,7 +2434,8 @@ static int set_bitmap_file(mddev_t *mddev, int fd)
mdname(mddev));
fput(mddev->bitmap_file);
mddev->bitmap_file = NULL;
}
} else
mddev->bitmap_offset = 0; /* file overrides offset */
return err;
}
......@@ -3774,6 +3803,13 @@ void md_check_recovery(mddev_t *mddev)
set_bit(MD_RECOVERY_RUNNING, &mddev->recovery);
if (!spares)
set_bit(MD_RECOVERY_SYNC, &mddev->recovery);
if (spares && mddev->bitmap && ! mddev->bitmap->file) {
/* We are adding a device or devices to an array
* which has the bitmap stored on all devices.
* So make sure all bitmap pages get written
*/
bitmap_write_all(mddev->bitmap);
}
mddev->sync_thread = md_register_thread(md_do_sync,
mddev,
"%s_resync");
......
......@@ -217,6 +217,7 @@ struct bitmap {
/* bitmap spinlock */
spinlock_t lock;
long offset; /* offset from superblock if file is NULL */
struct file *file; /* backing disk file */
struct page *sb_page; /* cached copy of the bitmap file superblock */
struct page **filemap; /* list of cache pages for the file */
......@@ -255,6 +256,7 @@ void bitmap_print_sb(struct bitmap *bitmap);
int bitmap_update_sb(struct bitmap *bitmap);
int bitmap_setallbits(struct bitmap *bitmap);
void bitmap_write_all(struct bitmap *bitmap);
/* these are exported */
int bitmap_startwrite(struct bitmap *bitmap, sector_t offset, unsigned long sectors);
......
......@@ -60,7 +60,14 @@
*/
#define MD_MAJOR_VERSION 0
#define MD_MINOR_VERSION 90
#define MD_PATCHLEVEL_VERSION 1
/*
* MD_PATCHLEVEL_VERSION indicates kernel functionality.
* >=1 means different superblock formats are selectable using SET_ARRAY_INFO
* and major_version/minor_version accordingly
* >=2 means that Internal bitmaps are supported by setting MD_SB_BITMAP_PRESENT
* in the super status byte
*/
#define MD_PATCHLEVEL_VERSION 2
extern int register_md_personality (int p_num, mdk_personality_t *p);
extern int unregister_md_personality (int p_num);
......@@ -78,6 +85,12 @@ extern void md_unplug_mddev(mddev_t *mddev);
extern void md_print_devices (void);
extern void md_super_write(mddev_t *mddev, mdk_rdev_t *rdev,
sector_t sector, int size, struct page *page);
extern int sync_page_io(struct block_device *bdev, sector_t sector, int size,
struct page *page, int rw);
#define MD_BUG(x...) { printk("md: bug in file %s, line %d\n", __FILE__, __LINE__); md_print_devices(); }
#endif
......
......@@ -273,6 +273,10 @@ struct mddev_s
struct bitmap *bitmap; /* the bitmap for the device */
struct file *bitmap_file; /* the bitmap file */
long bitmap_offset; /* offset from superblock of
* start of bitmap. May be
* negative, but not '0'
*/
struct list_head all_mddevs;
};
......
......@@ -96,6 +96,7 @@ typedef struct mdp_device_descriptor_s {
#define MD_SB_CLEAN 0
#define MD_SB_ERRORS 1
#define MD_SB_BITMAP_PRESENT 8 /* bitmap may be present nearby */
typedef struct mdp_superblock_s {
/*
* Constant generic information
......@@ -184,7 +185,7 @@ struct mdp_superblock_1 {
/* constant array information - 128 bytes */
__u32 magic; /* MD_SB_MAGIC: 0xa92b4efc - little endian */
__u32 major_version; /* 1 */
__u32 feature_map; /* 0 for now */
__u32 feature_map; /* bit 0 set if 'bitmap_offset' is meaningful */
__u32 pad0; /* always set to 0 when writing */
__u8 set_uuid[16]; /* user-space generated. */
......@@ -197,6 +198,10 @@ struct mdp_superblock_1 {
__u32 chunksize; /* in 512byte sectors */
__u32 raid_disks;
__u32 bitmap_offset; /* sectors after start of superblock that bitmap starts
* NOTE: signed, so bitmap can be before superblock
* only meaningful of feature_map[0] is set.
*/
__u8 pad1[128-96]; /* set to 0 when written */
/* constant this-device information - 64 bytes */
......
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