Commit ce25c31b authored by NeilBrown's avatar NeilBrown Committed by Linus Torvalds
Browse files

[PATCH] md: Change md/bitmap file handling to use bmap to file blocks-fix 



Fix problems with new bmap based access to bitmap files.

1/ When not using a file based bitmap, attach a NULL list of buffers
   to each page so the common free_buffer routine can cope.
2/ Use submit_bh to read as well as write, rather than vfs_read.
   This makes read and write more symetric.
3/ sync the file before reading, to ensure that the page cache has no
   dirty pages that might get written out later.

Signed-off-by: default avatarNeil Brown <neilb@suse.de>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent d785a06a

drivers/md/bitmap.c

+23 −24
Original line number Diff line number Diff line
@@ -247,6 +247,8 @@ static struct page *read_sb_page(mddev_t *mddev, long offset, unsigned long inde 


		if (sync_page_io(rdev->bdev, target, PAGE_SIZE, page, READ)) {

			page->index = index;

			attach_page_buffers(page, NULL); /* so that free_buffer will

							  * quietly no-op */

			return page;

		}

	}
@@ -349,11 +351,8 @@ static struct page *read_page(struct file *file, unsigned long index, 
{

	struct page *page = NULL;

	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);
@@ -364,18 +363,6 @@ static struct page *read_page(struct file *file, unsigned long index, 
	if (IS_ERR(page))

		goto out;



	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);
@@ -403,12 +390,22 @@ static struct page *read_page(struct file *file, unsigned long index, 


			bh->b_end_io = end_bitmap_write;

			bh->b_private = bitmap;

			atomic_inc(&bitmap->pending_writes);

			set_buffer_locked(bh);

			set_buffer_mapped(bh);

			submit_bh(READ, bh);

		}

		block++;

		bh = bh->b_this_page;

	}



	page->index = index;



	wait_event(bitmap->write_wait,

		   atomic_read(&bitmap->pending_writes)==0);

	if (bitmap->flags & BITMAP_WRITE_ERROR) {

		free_buffers(page);

		page = ERR_PTR(-EIO);

	}

out:

	if (IS_ERR(page))

		printk(KERN_ALERT "md: bitmap read error: (%dB @ %Lu): %ld\n",
@@ -1415,15 +1412,20 @@ int bitmap_create(mddev_t *mddev) 
		return -ENOMEM;



	spin_lock_init(&bitmap->lock);

	atomic_set(&bitmap->pending_writes, 0);

	init_waitqueue_head(&bitmap->write_wait);



	bitmap->mddev = mddev;



	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);



	if (file) {

		get_file(file);

		do_sync_file_range(file, 0, LLONG_MAX,

				   SYNC_FILE_RANGE_WAIT_BEFORE |

				   SYNC_FILE_RANGE_WRITE |

				   SYNC_FILE_RANGE_WAIT_AFTER);

	}

	/* read superblock from bitmap file (this sets bitmap->chunksize) */

	err = bitmap_read_sb(bitmap);

	if (err)
@@ -1446,9 +1448,6 @@ 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