[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)