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-rw-r--r--drivers/md/bitmap.c283
-rw-r--r--include/linux/raid/bitmap.h7
2 files changed, 139 insertions, 151 deletions
diff --git a/drivers/md/bitmap.c b/drivers/md/bitmap.c
index e40d3e4b8d27..bedd66e9e8ac 100644
--- a/drivers/md/bitmap.c
+++ b/drivers/md/bitmap.c
@@ -67,7 +67,6 @@ static inline char * bmname(struct bitmap *bitmap)
return bitmap->mddev ? mdname(bitmap->mddev) : "mdX";
}
-#define WRITE_POOL_SIZE 256
/*
* just a placeholder - calls kmalloc for bitmap pages
@@ -279,75 +278,137 @@ static int write_sb_page(mddev_t *mddev, long offset, struct page *page, int wai
*/
static int write_page(struct bitmap *bitmap, struct page *page, int wait)
{
- int ret = -ENOMEM;
+ struct buffer_head *bh;
if (bitmap->file == NULL)
return write_sb_page(bitmap->mddev, bitmap->offset, page, wait);
- flush_dcache_page(page); /* make sure visible to anyone reading the file */
+ bh = page_buffers(page);
- if (wait)
- lock_page(page);
- else {
- if (TestSetPageLocked(page))
- return -EAGAIN; /* already locked */
- if (PageWriteback(page)) {
- unlock_page(page);
- return -EAGAIN;
- }
+ while (bh && bh->b_blocknr) {
+ atomic_inc(&bitmap->pending_writes);
+ set_buffer_locked(bh);
+ set_buffer_mapped(bh);
+ submit_bh(WRITE, bh);
+ bh = bh->b_this_page;
+ }
+
+ if (wait) {
+ wait_event(bitmap->write_wait,
+ atomic_read(&bitmap->pending_writes)==0);
+ return (bitmap->flags & BITMAP_WRITE_ERROR) ? -EIO : 0;
}
+ return 0;
+}
+
+static void end_bitmap_write(struct buffer_head *bh, int uptodate)
+{
+ struct bitmap *bitmap = bh->b_private;
+ unsigned long flags;
- ret = page->mapping->a_ops->prepare_write(bitmap->file, page, 0, PAGE_SIZE);
- if (!ret)
- ret = page->mapping->a_ops->commit_write(bitmap->file, page, 0,
- PAGE_SIZE);
- if (ret) {
- unlock_page(page);
- return ret;
+ if (!uptodate) {
+ spin_lock_irqsave(&bitmap->lock, flags);
+ bitmap->flags |= BITMAP_WRITE_ERROR;
+ spin_unlock_irqrestore(&bitmap->lock, flags);
}
+ if (atomic_dec_and_test(&bitmap->pending_writes))
+ wake_up(&bitmap->write_wait);
+}
- set_page_dirty(page); /* force it to be written out */
+/* copied from buffer.c */
+static void
+__clear_page_buffers(struct page *page)
+{
+ ClearPagePrivate(page);
+ set_page_private(page, 0);
+ page_cache_release(page);
+}
+static void free_buffers(struct page *page)
+{
+ struct buffer_head *bh = page_buffers(page);
- if (!wait) {
- /* add to list to be waited for */
- struct page_list *item = mempool_alloc(bitmap->write_pool, GFP_NOIO);
- item->page = page;
- spin_lock(&bitmap->write_lock);
- list_add(&item->list, &bitmap->complete_pages);
- spin_unlock(&bitmap->write_lock);
+ while (bh) {
+ struct buffer_head *next = bh->b_this_page;
+ free_buffer_head(bh);
+ bh = next;
}
- return write_one_page(page, wait);
+ __clear_page_buffers(page);
+ put_page(page);
}
-/* read a page from a file, pinning it into cache, and return bytes_read */
+/* read a page from a file.
+ * We both read the page, and attach buffers to the page to record the
+ * address of each block (using bmap). These addresses will be used
+ * to write the block later, completely bypassing the filesystem.
+ * This usage is similar to how swap files are handled, and allows us
+ * to write to a file with no concerns of memory allocation failing.
+ */
static struct page *read_page(struct file *file, unsigned long index,
- unsigned long *bytes_read)
+ struct bitmap *bitmap,
+ unsigned long count)
{
- struct inode *inode = file->f_mapping->host;
struct page *page = NULL;
- loff_t isize = i_size_read(inode);
- unsigned long end_index = isize >> PAGE_SHIFT;
+ struct inode *inode = file->f_dentry->d_inode;
+ loff_t pos = index << PAGE_SHIFT;
+ int ret;
+ struct buffer_head *bh;
+ sector_t block;
+ mm_segment_t oldfs;
PRINTK("read bitmap file (%dB @ %Lu)\n", (int)PAGE_SIZE,
(unsigned long long)index << PAGE_SHIFT);
- page = read_cache_page(inode->i_mapping, index,
- (filler_t *)inode->i_mapping->a_ops->readpage, file);
+ page = alloc_page(GFP_KERNEL);
+ if (!page)
+ page = ERR_PTR(-ENOMEM);
if (IS_ERR(page))
goto out;
- wait_on_page_locked(page);
- if (!PageUptodate(page) || PageError(page)) {
+
+ oldfs = get_fs();
+ set_fs(KERNEL_DS);
+ ret = vfs_read(file, (char __user*) page_address(page), count, &pos);
+ set_fs(oldfs);
+
+ if (ret >= 0 && ret != count)
+ ret = -EIO;
+ if (ret < 0) {
+ put_page(page);
+ page = ERR_PTR(ret);
+ goto out;
+ }
+ bh = alloc_page_buffers(page, 1<<inode->i_blkbits, 0);
+ if (!bh) {
put_page(page);
- page = ERR_PTR(-EIO);
+ page = ERR_PTR(-ENOMEM);
goto out;
}
+ attach_page_buffers(page, bh);
+ block = index << (PAGE_SHIFT - inode->i_blkbits);
+ while (bh) {
+ if (count == 0)
+ bh->b_blocknr = 0;
+ else {
+ bh->b_blocknr = bmap(inode, block);
+ if (bh->b_blocknr == 0) {
+ /* Cannot use this file! */
+ free_buffers(page);
+ page = ERR_PTR(-EINVAL);
+ goto out;
+ }
+ bh->b_bdev = inode->i_sb->s_bdev;
+ if (count < (1<<inode->i_blkbits))
+ count = 0;
+ else
+ count -= (1<<inode->i_blkbits);
+
+ bh->b_end_io = end_bitmap_write;
+ bh->b_private = bitmap;
+ }
+ block++;
+ bh = bh->b_this_page;
+ }
- if (index > end_index) /* we have read beyond EOF */
- *bytes_read = 0;
- else if (index == end_index) /* possible short read */
- *bytes_read = isize & ~PAGE_MASK;
- else
- *bytes_read = PAGE_SIZE; /* got a full page */
+ page->index = index;
out:
if (IS_ERR(page))
printk(KERN_ALERT "md: bitmap read error: (%dB @ %Lu): %ld\n",
@@ -418,16 +479,14 @@ static int bitmap_read_sb(struct bitmap *bitmap)
char *reason = NULL;
bitmap_super_t *sb;
unsigned long chunksize, daemon_sleep, write_behind;
- unsigned long bytes_read;
unsigned long long events;
int err = -EINVAL;
/* page 0 is the superblock, read it... */
if (bitmap->file)
- bitmap->sb_page = read_page(bitmap->file, 0, &bytes_read);
+ bitmap->sb_page = read_page(bitmap->file, 0, bitmap, PAGE_SIZE);
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);
@@ -437,13 +496,6 @@ static int bitmap_read_sb(struct bitmap *bitmap)
sb = (bitmap_super_t *)kmap_atomic(bitmap->sb_page, KM_USER0);
- if (bytes_read < sizeof(*sb)) { /* short read */
- printk(KERN_INFO "%s: bitmap file superblock truncated\n",
- bmname(bitmap));
- err = -ENOSPC;
- goto out;
- }
-
chunksize = le32_to_cpu(sb->chunksize);
daemon_sleep = le32_to_cpu(sb->daemon_sleep);
write_behind = le32_to_cpu(sb->write_behind);
@@ -589,37 +641,12 @@ static void bitmap_file_unmap(struct bitmap *bitmap)
while (pages--)
if (map[pages]->index != 0) /* 0 is sb_page, release it below */
- put_page(map[pages]);
+ free_buffers(map[pages]);
kfree(map);
kfree(attr);
- safe_put_page(sb_page);
-}
-
-/* dequeue the next item in a page list -- don't call from irq context */
-static struct page_list *dequeue_page(struct bitmap *bitmap)
-{
- struct page_list *item = NULL;
- struct list_head *head = &bitmap->complete_pages;
-
- spin_lock(&bitmap->write_lock);
- if (list_empty(head))
- goto out;
- item = list_entry(head->prev, struct page_list, list);
- list_del(head->prev);
-out:
- spin_unlock(&bitmap->write_lock);
- return item;
-}
-
-static void drain_write_queues(struct bitmap *bitmap)
-{
- struct page_list *item;
-
- while ((item = dequeue_page(bitmap))) {
- /* don't bother to wait */
- mempool_free(item, bitmap->write_pool);
- }
+ if (sb_page)
+ free_buffers(sb_page);
}
static void bitmap_file_put(struct bitmap *bitmap)
@@ -632,12 +659,16 @@ static void bitmap_file_put(struct bitmap *bitmap)
bitmap->file = NULL;
spin_unlock_irqrestore(&bitmap->lock, flags);
- drain_write_queues(bitmap);
-
+ if (file)
+ wait_event(bitmap->write_wait,
+ atomic_read(&bitmap->pending_writes)==0);
bitmap_file_unmap(bitmap);
- if (file)
+ if (file) {
+ struct inode *inode = file->f_dentry->d_inode;
+ invalidate_inode_pages(inode->i_mapping);
fput(file);
+ }
}
@@ -728,8 +759,6 @@ static void bitmap_file_set_bit(struct bitmap *bitmap, sector_t block)
}
-static void bitmap_writeback(struct bitmap *bitmap);
-
/* this gets called when the md device is ready to unplug its underlying
* (slave) device queues -- before we let any writes go down, we need to
* sync the dirty pages of the bitmap file to disk */
@@ -761,24 +790,18 @@ int bitmap_unplug(struct bitmap *bitmap)
wait = 1;
spin_unlock_irqrestore(&bitmap->lock, flags);
- if (dirty | need_write) {
+ if (dirty | need_write)
err = write_page(bitmap, page, 0);
- if (err == -EAGAIN) {
- if (dirty)
- err = write_page(bitmap, page, 1);
- else
- err = 0;
- }
- if (err)
- return 1;
- }
}
if (wait) { /* if any writes were performed, we need to wait on them */
if (bitmap->file)
- bitmap_writeback(bitmap);
+ wait_event(bitmap->write_wait,
+ atomic_read(&bitmap->pending_writes)==0);
else
md_super_wait(bitmap->mddev);
}
+ if (bitmap->flags & BITMAP_WRITE_ERROR)
+ bitmap_file_kick(bitmap);
return 0;
}
@@ -800,7 +823,7 @@ static int bitmap_init_from_disk(struct bitmap *bitmap, sector_t start)
struct page *page = NULL, *oldpage = NULL;
unsigned long num_pages, bit_cnt = 0;
struct file *file;
- unsigned long bytes, offset, dummy;
+ unsigned long bytes, offset;
int outofdate;
int ret = -ENOSPC;
void *paddr;
@@ -853,7 +876,12 @@ static int bitmap_init_from_disk(struct bitmap *bitmap, sector_t start)
index = file_page_index(i);
bit = file_page_offset(i);
if (index != oldindex) { /* this is a new page, read it in */
+ int count;
/* unmap the old page, we're done with it */
+ if (index == num_pages-1)
+ count = bytes - index * PAGE_SIZE;
+ else
+ count = PAGE_SIZE;
if (index == 0) {
/*
* if we're here then the superblock page
@@ -863,7 +891,7 @@ static int bitmap_init_from_disk(struct bitmap *bitmap, sector_t start)
page = bitmap->sb_page;
offset = sizeof(bitmap_super_t);
} else if (file) {
- page = read_page(file, index, &dummy);
+ page = read_page(file, index, bitmap, count);
offset = 0;
} else {
page = read_sb_page(bitmap->mddev, bitmap->offset, index);
@@ -999,9 +1027,6 @@ int bitmap_daemon_work(struct bitmap *bitmap)
spin_unlock_irqrestore(&bitmap->lock, flags);
if (need_write) {
switch (write_page(bitmap, page, 0)) {
- case -EAGAIN:
- set_page_attr(bitmap, page, BITMAP_PAGE_NEEDWRITE);
- break;
case 0:
break;
default:
@@ -1017,10 +1042,6 @@ int bitmap_daemon_work(struct bitmap *bitmap)
clear_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
spin_unlock_irqrestore(&bitmap->lock, flags);
err = write_page(bitmap, lastpage, 0);
- if (err == -EAGAIN) {
- err = 0;
- set_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
- }
} else {
set_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
spin_unlock_irqrestore(&bitmap->lock, flags);
@@ -1070,10 +1091,6 @@ int bitmap_daemon_work(struct bitmap *bitmap)
clear_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
spin_unlock_irqrestore(&bitmap->lock, flags);
err = write_page(bitmap, lastpage, 0);
- if (err == -EAGAIN) {
- set_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
- err = 0;
- }
} else {
set_page_attr(bitmap, lastpage, BITMAP_PAGE_NEEDWRITE);
spin_unlock_irqrestore(&bitmap->lock, flags);
@@ -1083,32 +1100,6 @@ int bitmap_daemon_work(struct bitmap *bitmap)
return err;
}
-static void bitmap_writeback(struct bitmap *bitmap)
-{
- struct page *page;
- struct page_list *item;
- int err = 0;
-
- PRINTK("%s: bitmap writeback daemon woke up...\n", bmname(bitmap));
- /* wait on bitmap page writebacks */
- while ((item = dequeue_page(bitmap))) {
- page = item->page;
- mempool_free(item, bitmap->write_pool);
- PRINTK("wait on page writeback: %p\n", page);
- wait_on_page_writeback(page);
- PRINTK("finished page writeback: %p\n", page);
-
- err = PageError(page);
- if (err) {
- printk(KERN_WARNING "%s: bitmap file writeback "
- "failed (page %lu): %d\n",
- bmname(bitmap), page->index, err);
- bitmap_file_kick(bitmap);
- break;
- }
- }
-}
-
static bitmap_counter_t *bitmap_get_counter(struct bitmap *bitmap,
sector_t offset, int *blocks,
int create)
@@ -1377,8 +1368,6 @@ static void bitmap_free(struct bitmap *bitmap)
/* free all allocated memory */
- mempool_destroy(bitmap->write_pool);
-
if (bp) /* deallocate the page memory */
for (k = 0; k < pages; k++)
if (bp[k].map && !bp[k].hijacked)
@@ -1428,17 +1417,13 @@ int bitmap_create(mddev_t *mddev)
spin_lock_init(&bitmap->lock);
bitmap->mddev = mddev;
- spin_lock_init(&bitmap->write_lock);
- INIT_LIST_HEAD(&bitmap->complete_pages);
- bitmap->write_pool = mempool_create_kmalloc_pool(WRITE_POOL_SIZE,
- sizeof(struct page_list));
- err = -ENOMEM;
- if (!bitmap->write_pool)
- goto error;
-
bitmap->file = file;
bitmap->offset = mddev->bitmap_offset;
if (file) get_file(file);
+
+ /* Ensure we read fresh data */
+ invalidate_inode_pages(file->f_dentry->d_inode->i_mapping);
+
/* read superblock from bitmap file (this sets bitmap->chunksize) */
err = bitmap_read_sb(bitmap);
if (err)
@@ -1461,6 +1446,9 @@ int bitmap_create(mddev_t *mddev)
bitmap->syncchunk = ~0UL;
+ atomic_set(&bitmap->pending_writes, 0);
+ init_waitqueue_head(&bitmap->write_wait);
+
#ifdef INJECT_FATAL_FAULT_1
bitmap->bp = NULL;
#else
@@ -1503,4 +1491,3 @@ EXPORT_SYMBOL(bitmap_start_sync);
EXPORT_SYMBOL(bitmap_end_sync);
EXPORT_SYMBOL(bitmap_unplug);
EXPORT_SYMBOL(bitmap_close_sync);
-EXPORT_SYMBOL(bitmap_daemon_work);
diff --git a/include/linux/raid/bitmap.h b/include/linux/raid/bitmap.h
index 9c8907ca60a7..63df898fe2e9 100644
--- a/include/linux/raid/bitmap.h
+++ b/include/linux/raid/bitmap.h
@@ -140,6 +140,7 @@ typedef __u16 bitmap_counter_t;
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_WRITE_ERROR = 0x004, /* A write error has occurred */
BITMAP_HOSTENDIAN = 0x8000,
};
@@ -244,9 +245,9 @@ struct bitmap {
unsigned long daemon_lastrun; /* jiffies of last run */
unsigned long daemon_sleep; /* how many seconds between updates? */
- spinlock_t write_lock;
- struct list_head complete_pages;
- mempool_t *write_pool;
+ atomic_t pending_writes; /* pending writes to the bitmap file */
+ wait_queue_head_t write_wait;
+
};
/* the bitmap API */
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.