[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: Neil Brown <neilb@cse.unsw.edu.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/drivers/md/bitmap.c b/drivers/md/bitmap.c
index 204564d..030d686 100644
--- a/drivers/md/bitmap.c
+++ b/drivers/md/bitmap.c
@@ -116,7 +116,7 @@
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 @@
* 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 @@
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 @@
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 @@
void *kaddr;
unsigned long chunk = block >> CHUNK_BLOCK_SHIFT(bitmap);
- if (!bitmap->file || !bitmap->filemap) {
+ if (!bitmap->filemap) {
return;
}
@@ -715,7 +770,7 @@
* 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 @@
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 @@
chunks = bitmap->chunks;
file = bitmap->file;
- BUG_ON(!file);
+ BUG_ON(!file && !bitmap->offset);
#if INJECT_FAULTS_3
outofdate = 1;
@@ -779,7 +838,7 @@
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 @@
*/
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 @@
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 @@
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 @@
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 @@
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 @@
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)
diff --git a/drivers/md/md.c b/drivers/md/md.c
index 7075beb..fde8acf 100644
--- a/drivers/md/md.c
+++ b/drivers/md/md.c
@@ -337,7 +337,7 @@
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 @@
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 @@
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 @@
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 @@
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 @@
mdname(mddev));
fput(mddev->bitmap_file);
mddev->bitmap_file = NULL;
- }
+ } else
+ mddev->bitmap_offset = 0; /* file overrides offset */
return err;
}
@@ -3774,6 +3803,13 @@
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");
diff --git a/include/linux/raid/bitmap.h b/include/linux/raid/bitmap.h
index cfe60cf..e24b74b 100644
--- a/include/linux/raid/bitmap.h
+++ b/include/linux/raid/bitmap.h
@@ -217,6 +217,7 @@
/* 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 @@
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);
diff --git a/include/linux/raid/md.h b/include/linux/raid/md.h
index 75f41d8..ffa316c 100644
--- a/include/linux/raid/md.h
+++ b/include/linux/raid/md.h
@@ -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_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
diff --git a/include/linux/raid/md_k.h b/include/linux/raid/md_k.h
index 3e97702..a3725b5 100644
--- a/include/linux/raid/md_k.h
+++ b/include/linux/raid/md_k.h
@@ -273,6 +273,10 @@
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;
};
diff --git a/include/linux/raid/md_p.h b/include/linux/raid/md_p.h
index 8ba95d6..8e592a2 100644
--- a/include/linux/raid/md_p.h
+++ b/include/linux/raid/md_p.h
@@ -96,6 +96,7 @@
#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 @@
/* 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 @@
__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 */
