linux/drivers/md/md-bitmap.c

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// SPDX-License-Identifier: GPL-2.0-only
/*
* bitmap.c two-level bitmap (C) Peter T. Breuer (ptb@ot.uc3m.es) 2003
*
* bitmap_create - sets up the bitmap structure
* bitmap_destroy - destroys the bitmap structure
*
* additions, Copyright (C) 2003-2004, Paul Clements, SteelEye Technology, Inc.:
* - added disk storage for bitmap
* - changes to allow various bitmap chunk sizes
*/
/*
* Still to do:
*
* flush after percent set rather than just time based. (maybe both).
*/
#include <linux/blkdev.h>
#include <linux/module.h>
#include <linux/errno.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/timer.h>
#include <linux/sched.h>
#include <linux/list.h>
#include <linux/file.h>
#include <linux/mount.h>
#include <linux/buffer_head.h>
#include <linux/seq_file.h>
#include <trace/events/block.h>
#include "md.h"
#include "md-bitmap.h"
static inline char *bmname(struct bitmap *bitmap)
{
return bitmap->mddev ? mdname(bitmap->mddev) : "mdX";
}
/*
* check a page and, if necessary, allocate it (or hijack it if the alloc fails)
*
* 1) check to see if this page is allocated, if it's not then try to alloc
* 2) if the alloc fails, set the page's hijacked flag so we'll use the
* page pointer directly as a counter
*
* if we find our page, we increment the page's refcount so that it stays
* allocated while we're using it
*/
static int md_bitmap_checkpage(struct bitmap_counts *bitmap,
unsigned long page, int create, int no_hijack)
__releases(bitmap->lock)
__acquires(bitmap->lock)
{
unsigned char *mappage;
if (page >= bitmap->pages) {
/* This can happen if bitmap_start_sync goes beyond
* End-of-device while looking for a whole page.
* It is harmless.
*/
return -EINVAL;
}
if (bitmap->bp[page].hijacked) /* it's hijacked, don't try to alloc */
return 0;
if (bitmap->bp[page].map) /* page is already allocated, just return */
return 0;
if (!create)
return -ENOENT;
/* this page has not been allocated yet */
spin_unlock_irq(&bitmap->lock);
/* It is possible that this is being called inside a
* prepare_to_wait/finish_wait loop from raid5c:make_request().
* In general it is not permitted to sleep in that context as it
* can cause the loop to spin freely.
* That doesn't apply here as we can only reach this point
* once with any loop.
* When this function completes, either bp[page].map or
* bp[page].hijacked. In either case, this function will
* abort before getting to this point again. So there is
* no risk of a free-spin, and so it is safe to assert
* that sleeping here is allowed.
*/
sched_annotate_sleep();
mappage = kzalloc(PAGE_SIZE, GFP_NOIO);
spin_lock_irq(&bitmap->lock);
if (mappage == NULL) {
pr_debug("md/bitmap: map page allocation failed, hijacking\n");
/* We don't support hijack for cluster raid */
if (no_hijack)
return -ENOMEM;
/* failed - set the hijacked flag so that we can use the
* pointer as a counter */
if (!bitmap->bp[page].map)
bitmap->bp[page].hijacked = 1;
} else if (bitmap->bp[page].map ||
bitmap->bp[page].hijacked) {
/* somebody beat us to getting the page */
kfree(mappage);
} else {
/* no page was in place and we have one, so install it */
bitmap->bp[page].map = mappage;
bitmap->missing_pages--;
}
return 0;
}
/* if page is completely empty, put it back on the free list, or dealloc it */
/* if page was hijacked, unmark the flag so it might get alloced next time */
/* Note: lock should be held when calling this */
static void md_bitmap_checkfree(struct bitmap_counts *bitmap, unsigned long page)
{
char *ptr;
if (bitmap->bp[page].count) /* page is still busy */
return;
/* page is no longer in use, it can be released */
if (bitmap->bp[page].hijacked) { /* page was hijacked, undo this now */
bitmap->bp[page].hijacked = 0;
bitmap->bp[page].map = NULL;
} else {
/* normal case, free the page */
ptr = bitmap->bp[page].map;
bitmap->bp[page].map = NULL;
bitmap->missing_pages++;
kfree(ptr);
}
}
/*
* bitmap file handling - read and write the bitmap file and its superblock
*/
/*
* basic page I/O operations
*/
/* IO operations when bitmap is stored near all superblocks */
static int read_sb_page(struct mddev *mddev, loff_t offset,
struct page *page,
unsigned long index, int size)
{
/* choose a good rdev and read the page from there */
struct md_rdev *rdev;
sector_t target;
rdev_for_each(rdev, mddev) {
if (! test_bit(In_sync, &rdev->flags)
|| test_bit(Faulty, &rdev->flags)
|| test_bit(Bitmap_sync, &rdev->flags))
continue;
target = offset + index * (PAGE_SIZE/512);
if (sync_page_io(rdev, target,
roundup(size, bdev_logical_block_size(rdev->bdev)),
page, REQ_OP_READ, 0, true)) {
page->index = index;
return 0;
}
}
return -EIO;
}
static struct md_rdev *next_active_rdev(struct md_rdev *rdev, struct mddev *mddev)
{
/* Iterate the disks of an mddev, using rcu to protect access to the
* linked list, and raising the refcount of devices we return to ensure
* they don't disappear while in use.
* As devices are only added or removed when raid_disk is < 0 and
* nr_pending is 0 and In_sync is clear, the entries we return will
* still be in the same position on the list when we re-enter
* list_for_each_entry_continue_rcu.
*
* Note that if entered with 'rdev == NULL' to start at the
* beginning, we temporarily assign 'rdev' to an address which
* isn't really an rdev, but which can be used by
* list_for_each_entry_continue_rcu() to find the first entry.
*/
rcu_read_lock();
if (rdev == NULL)
/* start at the beginning */
rdev = list_entry(&mddev->disks, struct md_rdev, same_set);
else {
/* release the previous rdev and start from there. */
rdev_dec_pending(rdev, mddev);
}
list_for_each_entry_continue_rcu(rdev, &mddev->disks, same_set) {
if (rdev->raid_disk >= 0 &&
!test_bit(Faulty, &rdev->flags)) {
/* this is a usable devices */
atomic_inc(&rdev->nr_pending);
rcu_read_unlock();
return rdev;
}
}
rcu_read_unlock();
return NULL;
}
static int write_sb_page(struct bitmap *bitmap, struct page *page, int wait)
{
struct md_rdev *rdev;
struct block_device *bdev;
struct mddev *mddev = bitmap->mddev;
struct bitmap_storage *store = &bitmap->storage;
restart:
rdev = NULL;
while ((rdev = next_active_rdev(rdev, mddev)) != NULL) {
int size = PAGE_SIZE;
loff_t offset = mddev->bitmap_info.offset;
bdev = (rdev->meta_bdev) ? rdev->meta_bdev : rdev->bdev;
if (page->index == store->file_pages-1) {
int last_page_size = store->bytes & (PAGE_SIZE-1);
if (last_page_size == 0)
last_page_size = PAGE_SIZE;
size = roundup(last_page_size,
bdev_logical_block_size(bdev));
}
/* Just make sure we aren't corrupting data or
* metadata
*/
if (mddev->external) {
/* Bitmap could be anywhere. */
if (rdev->sb_start + offset + (page->index
* (PAGE_SIZE/512))
> rdev->data_offset
&&
rdev->sb_start + offset
< (rdev->data_offset + mddev->dev_sectors
+ (PAGE_SIZE/512)))
goto bad_alignment;
} else if (offset < 0) {
/* DATA BITMAP METADATA */
if (offset
+ (long)(page->index * (PAGE_SIZE/512))
+ size/512 > 0)
/* bitmap runs in to metadata */
goto bad_alignment;
if (rdev->data_offset + mddev->dev_sectors
> rdev->sb_start + offset)
/* data runs in to bitmap */
goto bad_alignment;
} else if (rdev->sb_start < rdev->data_offset) {
/* METADATA BITMAP DATA */
if (rdev->sb_start
+ offset
+ page->index*(PAGE_SIZE/512) + size/512
> rdev->data_offset)
/* bitmap runs in to data */
goto bad_alignment;
} else {
/* DATA METADATA BITMAP - no problems */
}
md_super_write(mddev, rdev,
rdev->sb_start + offset
+ page->index * (PAGE_SIZE/512),
size,
page);
}
if (wait && md_super_wait(mddev) < 0)
goto restart;
return 0;
bad_alignment:
return -EINVAL;
}
static void md_bitmap_file_kick(struct bitmap *bitmap);
/*
* write out a page to a file
*/
static void write_page(struct bitmap *bitmap, struct page *page, int wait)
{
[PATCH] md/bitmap: change md/bitmap file handling to use bmap to file blocks If md is asked to store a bitmap in a file, it tries to hold onto the page cache pages for that file, manipulate them directly, and call a cocktail of operations to write the file out. I don't believe this is a supportable approach. This patch changes the approach to use the same approach as swap files. i.e. bmap is used to enumerate all the block address of parts of the file and we write directly to those blocks of the device. swapfile only uses parts of the file that provide a full pages at contiguous addresses. We don't have that luxury so we have to cope with pages that are non-contiguous in storage. To handle this we attach buffers to each page, and store the addresses in those buffers. With this approach the pagecache may contain data which is inconsistent with what is on disk. To alleviate the problems this can cause, md invalidates the pagecache when releasing the file. If the file is to be examined while the array is active (a non-critical but occasionally useful function), O_DIRECT io must be used. And new version of mdadm will have support for this. This approach simplifies a lot of code: - we no longer need to keep a list of pages which we need to wait for, as the b_endio function can keep track of how many outstanding writes there are. This saves a mempool. - -EAGAIN returns from write_page are no longer possible (not sure if they ever were actually). Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-26 15:27:48 +08:00
struct buffer_head *bh;
if (bitmap->storage.file == NULL) {
switch (write_sb_page(bitmap, page, wait)) {
case -EINVAL:
set_bit(BITMAP_WRITE_ERROR, &bitmap->flags);
}
} else {
bh = page_buffers(page);
while (bh && bh->b_blocknr) {
atomic_inc(&bitmap->pending_writes);
set_buffer_locked(bh);
set_buffer_mapped(bh);
submit_bh(REQ_OP_WRITE, REQ_SYNC, bh);
bh = bh->b_this_page;
}
[PATCH] md/bitmap: change md/bitmap file handling to use bmap to file blocks If md is asked to store a bitmap in a file, it tries to hold onto the page cache pages for that file, manipulate them directly, and call a cocktail of operations to write the file out. I don't believe this is a supportable approach. This patch changes the approach to use the same approach as swap files. i.e. bmap is used to enumerate all the block address of parts of the file and we write directly to those blocks of the device. swapfile only uses parts of the file that provide a full pages at contiguous addresses. We don't have that luxury so we have to cope with pages that are non-contiguous in storage. To handle this we attach buffers to each page, and store the addresses in those buffers. With this approach the pagecache may contain data which is inconsistent with what is on disk. To alleviate the problems this can cause, md invalidates the pagecache when releasing the file. If the file is to be examined while the array is active (a non-critical but occasionally useful function), O_DIRECT io must be used. And new version of mdadm will have support for this. This approach simplifies a lot of code: - we no longer need to keep a list of pages which we need to wait for, as the b_endio function can keep track of how many outstanding writes there are. This saves a mempool. - -EAGAIN returns from write_page are no longer possible (not sure if they ever were actually). Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-26 15:27:48 +08:00
if (wait)
wait_event(bitmap->write_wait,
atomic_read(&bitmap->pending_writes)==0);
}
if (test_bit(BITMAP_WRITE_ERROR, &bitmap->flags))
md_bitmap_file_kick(bitmap);
[PATCH] md/bitmap: change md/bitmap file handling to use bmap to file blocks If md is asked to store a bitmap in a file, it tries to hold onto the page cache pages for that file, manipulate them directly, and call a cocktail of operations to write the file out. I don't believe this is a supportable approach. This patch changes the approach to use the same approach as swap files. i.e. bmap is used to enumerate all the block address of parts of the file and we write directly to those blocks of the device. swapfile only uses parts of the file that provide a full pages at contiguous addresses. We don't have that luxury so we have to cope with pages that are non-contiguous in storage. To handle this we attach buffers to each page, and store the addresses in those buffers. With this approach the pagecache may contain data which is inconsistent with what is on disk. To alleviate the problems this can cause, md invalidates the pagecache when releasing the file. If the file is to be examined while the array is active (a non-critical but occasionally useful function), O_DIRECT io must be used. And new version of mdadm will have support for this. This approach simplifies a lot of code: - we no longer need to keep a list of pages which we need to wait for, as the b_endio function can keep track of how many outstanding writes there are. This saves a mempool. - -EAGAIN returns from write_page are no longer possible (not sure if they ever were actually). Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-26 15:27:48 +08:00
}
static void end_bitmap_write(struct buffer_head *bh, int uptodate)
{
struct bitmap *bitmap = bh->b_private;
if (!uptodate)
set_bit(BITMAP_WRITE_ERROR, &bitmap->flags);
[PATCH] md/bitmap: change md/bitmap file handling to use bmap to file blocks If md is asked to store a bitmap in a file, it tries to hold onto the page cache pages for that file, manipulate them directly, and call a cocktail of operations to write the file out. I don't believe this is a supportable approach. This patch changes the approach to use the same approach as swap files. i.e. bmap is used to enumerate all the block address of parts of the file and we write directly to those blocks of the device. swapfile only uses parts of the file that provide a full pages at contiguous addresses. We don't have that luxury so we have to cope with pages that are non-contiguous in storage. To handle this we attach buffers to each page, and store the addresses in those buffers. With this approach the pagecache may contain data which is inconsistent with what is on disk. To alleviate the problems this can cause, md invalidates the pagecache when releasing the file. If the file is to be examined while the array is active (a non-critical but occasionally useful function), O_DIRECT io must be used. And new version of mdadm will have support for this. This approach simplifies a lot of code: - we no longer need to keep a list of pages which we need to wait for, as the b_endio function can keep track of how many outstanding writes there are. This saves a mempool. - -EAGAIN returns from write_page are no longer possible (not sure if they ever were actually). Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-26 15:27:48 +08:00
if (atomic_dec_and_test(&bitmap->pending_writes))
wake_up(&bitmap->write_wait);
}
[PATCH] md/bitmap: change md/bitmap file handling to use bmap to file blocks If md is asked to store a bitmap in a file, it tries to hold onto the page cache pages for that file, manipulate them directly, and call a cocktail of operations to write the file out. I don't believe this is a supportable approach. This patch changes the approach to use the same approach as swap files. i.e. bmap is used to enumerate all the block address of parts of the file and we write directly to those blocks of the device. swapfile only uses parts of the file that provide a full pages at contiguous addresses. We don't have that luxury so we have to cope with pages that are non-contiguous in storage. To handle this we attach buffers to each page, and store the addresses in those buffers. With this approach the pagecache may contain data which is inconsistent with what is on disk. To alleviate the problems this can cause, md invalidates the pagecache when releasing the file. If the file is to be examined while the array is active (a non-critical but occasionally useful function), O_DIRECT io must be used. And new version of mdadm will have support for this. This approach simplifies a lot of code: - we no longer need to keep a list of pages which we need to wait for, as the b_endio function can keep track of how many outstanding writes there are. This saves a mempool. - -EAGAIN returns from write_page are no longer possible (not sure if they ever were actually). Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-26 15:27:48 +08:00
static void free_buffers(struct page *page)
{
struct buffer_head *bh;
if (!PagePrivate(page))
return;
bh = page_buffers(page);
[PATCH] md/bitmap: change md/bitmap file handling to use bmap to file blocks If md is asked to store a bitmap in a file, it tries to hold onto the page cache pages for that file, manipulate them directly, and call a cocktail of operations to write the file out. I don't believe this is a supportable approach. This patch changes the approach to use the same approach as swap files. i.e. bmap is used to enumerate all the block address of parts of the file and we write directly to those blocks of the device. swapfile only uses parts of the file that provide a full pages at contiguous addresses. We don't have that luxury so we have to cope with pages that are non-contiguous in storage. To handle this we attach buffers to each page, and store the addresses in those buffers. With this approach the pagecache may contain data which is inconsistent with what is on disk. To alleviate the problems this can cause, md invalidates the pagecache when releasing the file. If the file is to be examined while the array is active (a non-critical but occasionally useful function), O_DIRECT io must be used. And new version of mdadm will have support for this. This approach simplifies a lot of code: - we no longer need to keep a list of pages which we need to wait for, as the b_endio function can keep track of how many outstanding writes there are. This saves a mempool. - -EAGAIN returns from write_page are no longer possible (not sure if they ever were actually). Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-26 15:27:48 +08:00
while (bh) {
struct buffer_head *next = bh->b_this_page;
free_buffer_head(bh);
bh = next;
}
detach_page_private(page);
[PATCH] md/bitmap: change md/bitmap file handling to use bmap to file blocks If md is asked to store a bitmap in a file, it tries to hold onto the page cache pages for that file, manipulate them directly, and call a cocktail of operations to write the file out. I don't believe this is a supportable approach. This patch changes the approach to use the same approach as swap files. i.e. bmap is used to enumerate all the block address of parts of the file and we write directly to those blocks of the device. swapfile only uses parts of the file that provide a full pages at contiguous addresses. We don't have that luxury so we have to cope with pages that are non-contiguous in storage. To handle this we attach buffers to each page, and store the addresses in those buffers. With this approach the pagecache may contain data which is inconsistent with what is on disk. To alleviate the problems this can cause, md invalidates the pagecache when releasing the file. If the file is to be examined while the array is active (a non-critical but occasionally useful function), O_DIRECT io must be used. And new version of mdadm will have support for this. This approach simplifies a lot of code: - we no longer need to keep a list of pages which we need to wait for, as the b_endio function can keep track of how many outstanding writes there are. This saves a mempool. - -EAGAIN returns from write_page are no longer possible (not sure if they ever were actually). Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-26 15:27:48 +08:00
put_page(page);
}
[PATCH] md/bitmap: change md/bitmap file handling to use bmap to file blocks If md is asked to store a bitmap in a file, it tries to hold onto the page cache pages for that file, manipulate them directly, and call a cocktail of operations to write the file out. I don't believe this is a supportable approach. This patch changes the approach to use the same approach as swap files. i.e. bmap is used to enumerate all the block address of parts of the file and we write directly to those blocks of the device. swapfile only uses parts of the file that provide a full pages at contiguous addresses. We don't have that luxury so we have to cope with pages that are non-contiguous in storage. To handle this we attach buffers to each page, and store the addresses in those buffers. With this approach the pagecache may contain data which is inconsistent with what is on disk. To alleviate the problems this can cause, md invalidates the pagecache when releasing the file. If the file is to be examined while the array is active (a non-critical but occasionally useful function), O_DIRECT io must be used. And new version of mdadm will have support for this. This approach simplifies a lot of code: - we no longer need to keep a list of pages which we need to wait for, as the b_endio function can keep track of how many outstanding writes there are. This saves a mempool. - -EAGAIN returns from write_page are no longer possible (not sure if they ever were actually). Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-26 15:27:48 +08:00
/* 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 int read_page(struct file *file, unsigned long index,
struct bitmap *bitmap,
unsigned long count,
struct page *page)
{
int ret = 0;
struct inode *inode = file_inode(file);
[PATCH] md/bitmap: change md/bitmap file handling to use bmap to file blocks If md is asked to store a bitmap in a file, it tries to hold onto the page cache pages for that file, manipulate them directly, and call a cocktail of operations to write the file out. I don't believe this is a supportable approach. This patch changes the approach to use the same approach as swap files. i.e. bmap is used to enumerate all the block address of parts of the file and we write directly to those blocks of the device. swapfile only uses parts of the file that provide a full pages at contiguous addresses. We don't have that luxury so we have to cope with pages that are non-contiguous in storage. To handle this we attach buffers to each page, and store the addresses in those buffers. With this approach the pagecache may contain data which is inconsistent with what is on disk. To alleviate the problems this can cause, md invalidates the pagecache when releasing the file. If the file is to be examined while the array is active (a non-critical but occasionally useful function), O_DIRECT io must be used. And new version of mdadm will have support for this. This approach simplifies a lot of code: - we no longer need to keep a list of pages which we need to wait for, as the b_endio function can keep track of how many outstanding writes there are. This saves a mempool. - -EAGAIN returns from write_page are no longer possible (not sure if they ever were actually). Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-26 15:27:48 +08:00
struct buffer_head *bh;
sector_t block, blk_cur;
unsigned long blocksize = i_blocksize(inode);
pr_debug("read bitmap file (%dB @ %llu)\n", (int)PAGE_SIZE,
(unsigned long long)index << PAGE_SHIFT);
bh = alloc_page_buffers(page, blocksize, false);
[PATCH] md/bitmap: change md/bitmap file handling to use bmap to file blocks If md is asked to store a bitmap in a file, it tries to hold onto the page cache pages for that file, manipulate them directly, and call a cocktail of operations to write the file out. I don't believe this is a supportable approach. This patch changes the approach to use the same approach as swap files. i.e. bmap is used to enumerate all the block address of parts of the file and we write directly to those blocks of the device. swapfile only uses parts of the file that provide a full pages at contiguous addresses. We don't have that luxury so we have to cope with pages that are non-contiguous in storage. To handle this we attach buffers to each page, and store the addresses in those buffers. With this approach the pagecache may contain data which is inconsistent with what is on disk. To alleviate the problems this can cause, md invalidates the pagecache when releasing the file. If the file is to be examined while the array is active (a non-critical but occasionally useful function), O_DIRECT io must be used. And new version of mdadm will have support for this. This approach simplifies a lot of code: - we no longer need to keep a list of pages which we need to wait for, as the b_endio function can keep track of how many outstanding writes there are. This saves a mempool. - -EAGAIN returns from write_page are no longer possible (not sure if they ever were actually). Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-26 15:27:48 +08:00
if (!bh) {
ret = -ENOMEM;
goto out;
}
attach_page_private(page, bh);
blk_cur = index << (PAGE_SHIFT - inode->i_blkbits);
[PATCH] md/bitmap: change md/bitmap file handling to use bmap to file blocks If md is asked to store a bitmap in a file, it tries to hold onto the page cache pages for that file, manipulate them directly, and call a cocktail of operations to write the file out. I don't believe this is a supportable approach. This patch changes the approach to use the same approach as swap files. i.e. bmap is used to enumerate all the block address of parts of the file and we write directly to those blocks of the device. swapfile only uses parts of the file that provide a full pages at contiguous addresses. We don't have that luxury so we have to cope with pages that are non-contiguous in storage. To handle this we attach buffers to each page, and store the addresses in those buffers. With this approach the pagecache may contain data which is inconsistent with what is on disk. To alleviate the problems this can cause, md invalidates the pagecache when releasing the file. If the file is to be examined while the array is active (a non-critical but occasionally useful function), O_DIRECT io must be used. And new version of mdadm will have support for this. This approach simplifies a lot of code: - we no longer need to keep a list of pages which we need to wait for, as the b_endio function can keep track of how many outstanding writes there are. This saves a mempool. - -EAGAIN returns from write_page are no longer possible (not sure if they ever were actually). Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-26 15:27:48 +08:00
while (bh) {
block = blk_cur;
[PATCH] md/bitmap: change md/bitmap file handling to use bmap to file blocks If md is asked to store a bitmap in a file, it tries to hold onto the page cache pages for that file, manipulate them directly, and call a cocktail of operations to write the file out. I don't believe this is a supportable approach. This patch changes the approach to use the same approach as swap files. i.e. bmap is used to enumerate all the block address of parts of the file and we write directly to those blocks of the device. swapfile only uses parts of the file that provide a full pages at contiguous addresses. We don't have that luxury so we have to cope with pages that are non-contiguous in storage. To handle this we attach buffers to each page, and store the addresses in those buffers. With this approach the pagecache may contain data which is inconsistent with what is on disk. To alleviate the problems this can cause, md invalidates the pagecache when releasing the file. If the file is to be examined while the array is active (a non-critical but occasionally useful function), O_DIRECT io must be used. And new version of mdadm will have support for this. This approach simplifies a lot of code: - we no longer need to keep a list of pages which we need to wait for, as the b_endio function can keep track of how many outstanding writes there are. This saves a mempool. - -EAGAIN returns from write_page are no longer possible (not sure if they ever were actually). Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-26 15:27:48 +08:00
if (count == 0)
bh->b_blocknr = 0;
else {
ret = bmap(inode, &block);
if (ret || !block) {
ret = -EINVAL;
bh->b_blocknr = 0;
[PATCH] md/bitmap: change md/bitmap file handling to use bmap to file blocks If md is asked to store a bitmap in a file, it tries to hold onto the page cache pages for that file, manipulate them directly, and call a cocktail of operations to write the file out. I don't believe this is a supportable approach. This patch changes the approach to use the same approach as swap files. i.e. bmap is used to enumerate all the block address of parts of the file and we write directly to those blocks of the device. swapfile only uses parts of the file that provide a full pages at contiguous addresses. We don't have that luxury so we have to cope with pages that are non-contiguous in storage. To handle this we attach buffers to each page, and store the addresses in those buffers. With this approach the pagecache may contain data which is inconsistent with what is on disk. To alleviate the problems this can cause, md invalidates the pagecache when releasing the file. If the file is to be examined while the array is active (a non-critical but occasionally useful function), O_DIRECT io must be used. And new version of mdadm will have support for this. This approach simplifies a lot of code: - we no longer need to keep a list of pages which we need to wait for, as the b_endio function can keep track of how many outstanding writes there are. This saves a mempool. - -EAGAIN returns from write_page are no longer possible (not sure if they ever were actually). Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-26 15:27:48 +08:00
goto out;
}
bh->b_blocknr = block;
[PATCH] md/bitmap: change md/bitmap file handling to use bmap to file blocks If md is asked to store a bitmap in a file, it tries to hold onto the page cache pages for that file, manipulate them directly, and call a cocktail of operations to write the file out. I don't believe this is a supportable approach. This patch changes the approach to use the same approach as swap files. i.e. bmap is used to enumerate all the block address of parts of the file and we write directly to those blocks of the device. swapfile only uses parts of the file that provide a full pages at contiguous addresses. We don't have that luxury so we have to cope with pages that are non-contiguous in storage. To handle this we attach buffers to each page, and store the addresses in those buffers. With this approach the pagecache may contain data which is inconsistent with what is on disk. To alleviate the problems this can cause, md invalidates the pagecache when releasing the file. If the file is to be examined while the array is active (a non-critical but occasionally useful function), O_DIRECT io must be used. And new version of mdadm will have support for this. This approach simplifies a lot of code: - we no longer need to keep a list of pages which we need to wait for, as the b_endio function can keep track of how many outstanding writes there are. This saves a mempool. - -EAGAIN returns from write_page are no longer possible (not sure if they ever were actually). Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-26 15:27:48 +08:00
bh->b_bdev = inode->i_sb->s_bdev;
if (count < blocksize)
[PATCH] md/bitmap: change md/bitmap file handling to use bmap to file blocks If md is asked to store a bitmap in a file, it tries to hold onto the page cache pages for that file, manipulate them directly, and call a cocktail of operations to write the file out. I don't believe this is a supportable approach. This patch changes the approach to use the same approach as swap files. i.e. bmap is used to enumerate all the block address of parts of the file and we write directly to those blocks of the device. swapfile only uses parts of the file that provide a full pages at contiguous addresses. We don't have that luxury so we have to cope with pages that are non-contiguous in storage. To handle this we attach buffers to each page, and store the addresses in those buffers. With this approach the pagecache may contain data which is inconsistent with what is on disk. To alleviate the problems this can cause, md invalidates the pagecache when releasing the file. If the file is to be examined while the array is active (a non-critical but occasionally useful function), O_DIRECT io must be used. And new version of mdadm will have support for this. This approach simplifies a lot of code: - we no longer need to keep a list of pages which we need to wait for, as the b_endio function can keep track of how many outstanding writes there are. This saves a mempool. - -EAGAIN returns from write_page are no longer possible (not sure if they ever were actually). Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-26 15:27:48 +08:00
count = 0;
else
count -= blocksize;
[PATCH] md/bitmap: change md/bitmap file handling to use bmap to file blocks If md is asked to store a bitmap in a file, it tries to hold onto the page cache pages for that file, manipulate them directly, and call a cocktail of operations to write the file out. I don't believe this is a supportable approach. This patch changes the approach to use the same approach as swap files. i.e. bmap is used to enumerate all the block address of parts of the file and we write directly to those blocks of the device. swapfile only uses parts of the file that provide a full pages at contiguous addresses. We don't have that luxury so we have to cope with pages that are non-contiguous in storage. To handle this we attach buffers to each page, and store the addresses in those buffers. With this approach the pagecache may contain data which is inconsistent with what is on disk. To alleviate the problems this can cause, md invalidates the pagecache when releasing the file. If the file is to be examined while the array is active (a non-critical but occasionally useful function), O_DIRECT io must be used. And new version of mdadm will have support for this. This approach simplifies a lot of code: - we no longer need to keep a list of pages which we need to wait for, as the b_endio function can keep track of how many outstanding writes there are. This saves a mempool. - -EAGAIN returns from write_page are no longer possible (not sure if they ever were actually). Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-26 15:27:48 +08:00
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(REQ_OP_READ, 0, bh);
[PATCH] md/bitmap: change md/bitmap file handling to use bmap to file blocks If md is asked to store a bitmap in a file, it tries to hold onto the page cache pages for that file, manipulate them directly, and call a cocktail of operations to write the file out. I don't believe this is a supportable approach. This patch changes the approach to use the same approach as swap files. i.e. bmap is used to enumerate all the block address of parts of the file and we write directly to those blocks of the device. swapfile only uses parts of the file that provide a full pages at contiguous addresses. We don't have that luxury so we have to cope with pages that are non-contiguous in storage. To handle this we attach buffers to each page, and store the addresses in those buffers. With this approach the pagecache may contain data which is inconsistent with what is on disk. To alleviate the problems this can cause, md invalidates the pagecache when releasing the file. If the file is to be examined while the array is active (a non-critical but occasionally useful function), O_DIRECT io must be used. And new version of mdadm will have support for this. This approach simplifies a lot of code: - we no longer need to keep a list of pages which we need to wait for, as the b_endio function can keep track of how many outstanding writes there are. This saves a mempool. - -EAGAIN returns from write_page are no longer possible (not sure if they ever were actually). Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-26 15:27:48 +08:00
}
blk_cur++;
[PATCH] md/bitmap: change md/bitmap file handling to use bmap to file blocks If md is asked to store a bitmap in a file, it tries to hold onto the page cache pages for that file, manipulate them directly, and call a cocktail of operations to write the file out. I don't believe this is a supportable approach. This patch changes the approach to use the same approach as swap files. i.e. bmap is used to enumerate all the block address of parts of the file and we write directly to those blocks of the device. swapfile only uses parts of the file that provide a full pages at contiguous addresses. We don't have that luxury so we have to cope with pages that are non-contiguous in storage. To handle this we attach buffers to each page, and store the addresses in those buffers. With this approach the pagecache may contain data which is inconsistent with what is on disk. To alleviate the problems this can cause, md invalidates the pagecache when releasing the file. If the file is to be examined while the array is active (a non-critical but occasionally useful function), O_DIRECT io must be used. And new version of mdadm will have support for this. This approach simplifies a lot of code: - we no longer need to keep a list of pages which we need to wait for, as the b_endio function can keep track of how many outstanding writes there are. This saves a mempool. - -EAGAIN returns from write_page are no longer possible (not sure if they ever were actually). Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-26 15:27:48 +08:00
bh = bh->b_this_page;
}
page->index = index;
wait_event(bitmap->write_wait,
atomic_read(&bitmap->pending_writes)==0);
if (test_bit(BITMAP_WRITE_ERROR, &bitmap->flags))
ret = -EIO;
out:
if (ret)
pr_err("md: bitmap read error: (%dB @ %llu): %d\n",
(int)PAGE_SIZE,
(unsigned long long)index << PAGE_SHIFT,
ret);
return ret;
}
/*
* bitmap file superblock operations
*/
/*
* md_bitmap_wait_writes() should be called before writing any bitmap
* blocks, to ensure previous writes, particularly from
* md_bitmap_daemon_work(), have completed.
*/
static void md_bitmap_wait_writes(struct bitmap *bitmap)
{
if (bitmap->storage.file)
wait_event(bitmap->write_wait,
atomic_read(&bitmap->pending_writes)==0);
else
/* Note that we ignore the return value. The writes
* might have failed, but that would just mean that
* some bits which should be cleared haven't been,
* which is safe. The relevant bitmap blocks will
* probably get written again, but there is no great
* loss if they aren't.
*/
md_super_wait(bitmap->mddev);
}
/* update the event counter and sync the superblock to disk */
void md_bitmap_update_sb(struct bitmap *bitmap)
{
bitmap_super_t *sb;
if (!bitmap || !bitmap->mddev) /* no bitmap for this array */
return;
if (bitmap->mddev->bitmap_info.external)
return;
if (!bitmap->storage.sb_page) /* no superblock */
return;
sb = kmap_atomic(bitmap->storage.sb_page);
sb->events = cpu_to_le64(bitmap->mddev->events);
if (bitmap->mddev->events < bitmap->events_cleared)
/* rocking back to read-only */
bitmap->events_cleared = bitmap->mddev->events;
sb->events_cleared = cpu_to_le64(bitmap->events_cleared);
/*
* clear BITMAP_WRITE_ERROR bit to protect against the case that
* a bitmap write error occurred but the later writes succeeded.
*/
sb->state = cpu_to_le32(bitmap->flags & ~BIT(BITMAP_WRITE_ERROR));
/* Just in case these have been changed via sysfs: */
sb->daemon_sleep = cpu_to_le32(bitmap->mddev->bitmap_info.daemon_sleep/HZ);
sb->write_behind = cpu_to_le32(bitmap->mddev->bitmap_info.max_write_behind);
/* This might have been changed by a reshape */
sb->sync_size = cpu_to_le64(bitmap->mddev->resync_max_sectors);
sb->chunksize = cpu_to_le32(bitmap->mddev->bitmap_info.chunksize);
sb->nodes = cpu_to_le32(bitmap->mddev->bitmap_info.nodes);
sb->sectors_reserved = cpu_to_le32(bitmap->mddev->
bitmap_info.space);
kunmap_atomic(sb);
write_page(bitmap, bitmap->storage.sb_page, 1);
}
EXPORT_SYMBOL(md_bitmap_update_sb);
/* print out the bitmap file superblock */
void md_bitmap_print_sb(struct bitmap *bitmap)
{
bitmap_super_t *sb;
if (!bitmap || !bitmap->storage.sb_page)
return;
sb = kmap_atomic(bitmap->storage.sb_page);
pr_debug("%s: bitmap file superblock:\n", bmname(bitmap));
pr_debug(" magic: %08x\n", le32_to_cpu(sb->magic));
pr_debug(" version: %d\n", le32_to_cpu(sb->version));
pr_debug(" uuid: %08x.%08x.%08x.%08x\n",
le32_to_cpu(*(__le32 *)(sb->uuid+0)),
le32_to_cpu(*(__le32 *)(sb->uuid+4)),
le32_to_cpu(*(__le32 *)(sb->uuid+8)),
le32_to_cpu(*(__le32 *)(sb->uuid+12)));
pr_debug(" events: %llu\n",
(unsigned long long) le64_to_cpu(sb->events));
pr_debug("events cleared: %llu\n",
(unsigned long long) le64_to_cpu(sb->events_cleared));
pr_debug(" state: %08x\n", le32_to_cpu(sb->state));
pr_debug(" chunksize: %d B\n", le32_to_cpu(sb->chunksize));
pr_debug(" daemon sleep: %ds\n", le32_to_cpu(sb->daemon_sleep));
pr_debug(" sync size: %llu KB\n",
(unsigned long long)le64_to_cpu(sb->sync_size)/2);
pr_debug("max write behind: %d\n", le32_to_cpu(sb->write_behind));
kunmap_atomic(sb);
}
/*
* bitmap_new_disk_sb
* @bitmap
*
* This function is somewhat the reverse of bitmap_read_sb. bitmap_read_sb
* reads and verifies the on-disk bitmap superblock and populates bitmap_info.
* This function verifies 'bitmap_info' and populates the on-disk bitmap
* structure, which is to be written to disk.
*
* Returns: 0 on success, -Exxx on error
*/
static int md_bitmap_new_disk_sb(struct bitmap *bitmap)
{
bitmap_super_t *sb;
unsigned long chunksize, daemon_sleep, write_behind;
bitmap->storage.sb_page = alloc_page(GFP_KERNEL | __GFP_ZERO);
if (bitmap->storage.sb_page == NULL)
return -ENOMEM;
bitmap->storage.sb_page->index = 0;
sb = kmap_atomic(bitmap->storage.sb_page);
sb->magic = cpu_to_le32(BITMAP_MAGIC);
sb->version = cpu_to_le32(BITMAP_MAJOR_HI);
chunksize = bitmap->mddev->bitmap_info.chunksize;
BUG_ON(!chunksize);
if (!is_power_of_2(chunksize)) {
kunmap_atomic(sb);
pr_warn("bitmap chunksize not a power of 2\n");
return -EINVAL;
}
sb->chunksize = cpu_to_le32(chunksize);
daemon_sleep = bitmap->mddev->bitmap_info.daemon_sleep;
if (!daemon_sleep || (daemon_sleep > MAX_SCHEDULE_TIMEOUT)) {
pr_debug("Choosing daemon_sleep default (5 sec)\n");
daemon_sleep = 5 * HZ;
}
sb->daemon_sleep = cpu_to_le32(daemon_sleep);
bitmap->mddev->bitmap_info.daemon_sleep = daemon_sleep;
/*
* FIXME: write_behind for RAID1. If not specified, what
* is a good choice? We choose COUNTER_MAX / 2 arbitrarily.
*/
write_behind = bitmap->mddev->bitmap_info.max_write_behind;
if (write_behind > COUNTER_MAX)
write_behind = COUNTER_MAX / 2;
sb->write_behind = cpu_to_le32(write_behind);
bitmap->mddev->bitmap_info.max_write_behind = write_behind;
/* keep the array size field of the bitmap superblock up to date */
sb->sync_size = cpu_to_le64(bitmap->mddev->resync_max_sectors);
memcpy(sb->uuid, bitmap->mddev->uuid, 16);
set_bit(BITMAP_STALE, &bitmap->flags);
sb->state = cpu_to_le32(bitmap->flags);
bitmap->events_cleared = bitmap->mddev->events;
sb->events_cleared = cpu_to_le64(bitmap->mddev->events);
bitmap->mddev->bitmap_info.nodes = 0;
kunmap_atomic(sb);
return 0;
}
/* read the superblock from the bitmap file and initialize some bitmap fields */
static int md_bitmap_read_sb(struct bitmap *bitmap)
{
char *reason = NULL;
bitmap_super_t *sb;
unsigned long chunksize, daemon_sleep, write_behind;
unsigned long long events;
int nodes = 0;
unsigned long sectors_reserved = 0;
int err = -EINVAL;
struct page *sb_page;
loff_t offset = bitmap->mddev->bitmap_info.offset;
if (!bitmap->storage.file && !bitmap->mddev->bitmap_info.offset) {
chunksize = 128 * 1024 * 1024;
daemon_sleep = 5 * HZ;
write_behind = 0;
set_bit(BITMAP_STALE, &bitmap->flags);
err = 0;
goto out_no_sb;
}
/* page 0 is the superblock, read it... */
sb_page = alloc_page(GFP_KERNEL);
if (!sb_page)
return -ENOMEM;
bitmap->storage.sb_page = sb_page;
re_read:
/* If cluster_slot is set, the cluster is setup */
if (bitmap->cluster_slot >= 0) {
sector_t bm_blocks = bitmap->mddev->resync_max_sectors;
bm_blocks = DIV_ROUND_UP_SECTOR_T(bm_blocks,
(bitmap->mddev->bitmap_info.chunksize >> 9));
/* bits to bytes */
bm_blocks = ((bm_blocks+7) >> 3) + sizeof(bitmap_super_t);
/* to 4k blocks */
bm_blocks = DIV_ROUND_UP_SECTOR_T(bm_blocks, 4096);
offset = bitmap->mddev->bitmap_info.offset + (bitmap->cluster_slot * (bm_blocks << 3));
pr_debug("%s:%d bm slot: %d offset: %llu\n", __func__, __LINE__,
bitmap->cluster_slot, offset);
}
if (bitmap->storage.file) {
loff_t isize = i_size_read(bitmap->storage.file->f_mapping->host);
int bytes = isize > PAGE_SIZE ? PAGE_SIZE : isize;
err = read_page(bitmap->storage.file, 0,
bitmap, bytes, sb_page);
} else {
err = read_sb_page(bitmap->mddev,
offset,
sb_page,
0, sizeof(bitmap_super_t));
}
if (err)
return err;
err = -EINVAL;
sb = kmap_atomic(sb_page);
chunksize = le32_to_cpu(sb->chunksize);
daemon_sleep = le32_to_cpu(sb->daemon_sleep) * HZ;
write_behind = le32_to_cpu(sb->write_behind);
sectors_reserved = le32_to_cpu(sb->sectors_reserved);
/* Setup nodes/clustername only if bitmap version is
* cluster-compatible
*/
if (sb->version == cpu_to_le32(BITMAP_MAJOR_CLUSTERED)) {
nodes = le32_to_cpu(sb->nodes);
strlcpy(bitmap->mddev->bitmap_info.cluster_name,
sb->cluster_name, 64);
}
/* verify that the bitmap-specific fields are valid */
if (sb->magic != cpu_to_le32(BITMAP_MAGIC))
reason = "bad magic";
else if (le32_to_cpu(sb->version) < BITMAP_MAJOR_LO ||
le32_to_cpu(sb->version) > BITMAP_MAJOR_CLUSTERED)
reason = "unrecognized superblock version";
else if (chunksize < 512)
reason = "bitmap chunksize too small";
else if (!is_power_of_2(chunksize))
reason = "bitmap chunksize not a power of 2";
else if (daemon_sleep < 1 || daemon_sleep > MAX_SCHEDULE_TIMEOUT)
reason = "daemon sleep period out of range";
else if (write_behind > COUNTER_MAX)
reason = "write-behind limit out of range (0 - 16383)";
if (reason) {
pr_warn("%s: invalid bitmap file superblock: %s\n",
bmname(bitmap), reason);
goto out;
}
/* keep the array size field of the bitmap superblock up to date */
sb->sync_size = cpu_to_le64(bitmap->mddev->resync_max_sectors);
if (bitmap->mddev->persistent) {
/*
* We have a persistent array superblock, so compare the
* bitmap's UUID and event counter to the mddev's
*/
if (memcmp(sb->uuid, bitmap->mddev->uuid, 16)) {
pr_warn("%s: bitmap superblock UUID mismatch\n",
bmname(bitmap));
goto out;
}
events = le64_to_cpu(sb->events);
if (!nodes && (events < bitmap->mddev->events)) {
pr_warn("%s: bitmap file is out of date (%llu < %llu) -- forcing full recovery\n",
bmname(bitmap), events,
(unsigned long long) bitmap->mddev->events);
set_bit(BITMAP_STALE, &bitmap->flags);
}
}
/* assign fields using values from superblock */
bitmap->flags |= le32_to_cpu(sb->state);
if (le32_to_cpu(sb->version) == BITMAP_MAJOR_HOSTENDIAN)
set_bit(BITMAP_HOSTENDIAN, &bitmap->flags);
bitmap->events_cleared = le64_to_cpu(sb->events_cleared);
strlcpy(bitmap->mddev->bitmap_info.cluster_name, sb->cluster_name, 64);
err = 0;
out:
kunmap_atomic(sb);
/* Assigning chunksize is required for "re_read" */
bitmap->mddev->bitmap_info.chunksize = chunksize;
if (err == 0 && nodes && (bitmap->cluster_slot < 0)) {
err = md_setup_cluster(bitmap->mddev, nodes);
if (err) {
pr_warn("%s: Could not setup cluster service (%d)\n",
bmname(bitmap), err);
goto out_no_sb;
}
bitmap->cluster_slot = md_cluster_ops->slot_number(bitmap->mddev);
goto re_read;
}
out_no_sb:
if (test_bit(BITMAP_STALE, &bitmap->flags))
bitmap->events_cleared = bitmap->mddev->events;
bitmap->mddev->bitmap_info.chunksize = chunksize;
bitmap->mddev->bitmap_info.daemon_sleep = daemon_sleep;
bitmap->mddev->bitmap_info.max_write_behind = write_behind;
bitmap->mddev->bitmap_info.nodes = nodes;
if (bitmap->mddev->bitmap_info.space == 0 ||
bitmap->mddev->bitmap_info.space > sectors_reserved)
bitmap->mddev->bitmap_info.space = sectors_reserved;
if (err) {
md_bitmap_print_sb(bitmap);
if (bitmap->cluster_slot < 0)
md_cluster_stop(bitmap->mddev);
}
return err;
}
/*
* general bitmap file operations
*/
/*
* on-disk bitmap:
*
* Use one bit per "chunk" (block set). We do the disk I/O on the bitmap
* file a page at a time. There's a superblock at the start of the file.
*/
/* calculate the index of the page that contains this bit */
static inline unsigned long file_page_index(struct bitmap_storage *store,
unsigned long chunk)
{
if (store->sb_page)
chunk += sizeof(bitmap_super_t) << 3;
return chunk >> PAGE_BIT_SHIFT;
}
/* calculate the (bit) offset of this bit within a page */
static inline unsigned long file_page_offset(struct bitmap_storage *store,
unsigned long chunk)
{
if (store->sb_page)
chunk += sizeof(bitmap_super_t) << 3;
return chunk & (PAGE_BITS - 1);
}
/*
* return a pointer to the page in the filemap that contains the given bit
*
*/
static inline struct page *filemap_get_page(struct bitmap_storage *store,
unsigned long chunk)
{
if (file_page_index(store, chunk) >= store->file_pages)
return NULL;
return store->filemap[file_page_index(store, chunk)];
}
static int md_bitmap_storage_alloc(struct bitmap_storage *store,
unsigned long chunks, int with_super,
int slot_number)
{
int pnum, offset = 0;
unsigned long num_pages;
unsigned long bytes;
bytes = DIV_ROUND_UP(chunks, 8);
if (with_super)
bytes += sizeof(bitmap_super_t);
num_pages = DIV_ROUND_UP(bytes, PAGE_SIZE);
offset = slot_number * num_pages;
treewide: kmalloc() -> kmalloc_array() The kmalloc() function has a 2-factor argument form, kmalloc_array(). This patch replaces cases of: kmalloc(a * b, gfp) with: kmalloc_array(a * b, gfp) as well as handling cases of: kmalloc(a * b * c, gfp) with: kmalloc(array3_size(a, b, c), gfp) as it's slightly less ugly than: kmalloc_array(array_size(a, b), c, gfp) This does, however, attempt to ignore constant size factors like: kmalloc(4 * 1024, gfp) though any constants defined via macros get caught up in the conversion. Any factors with a sizeof() of "unsigned char", "char", and "u8" were dropped, since they're redundant. The tools/ directory was manually excluded, since it has its own implementation of kmalloc(). The Coccinelle script used for this was: // Fix redundant parens around sizeof(). @@ type TYPE; expression THING, E; @@ ( kmalloc( - (sizeof(TYPE)) * E + sizeof(TYPE) * E , ...) | kmalloc( - (sizeof(THING)) * E + sizeof(THING) * E , ...) ) // Drop single-byte sizes and redundant parens. @@ expression COUNT; typedef u8; typedef __u8; @@ ( kmalloc( - sizeof(u8) * (COUNT) + COUNT , ...) | kmalloc( - sizeof(__u8) * (COUNT) + COUNT , ...) | kmalloc( - sizeof(char) * (COUNT) + COUNT , ...) | kmalloc( - sizeof(unsigned char) * (COUNT) + COUNT , ...) | kmalloc( - sizeof(u8) * COUNT + COUNT , ...) | kmalloc( - sizeof(__u8) * COUNT + COUNT , ...) | kmalloc( - sizeof(char) * COUNT + COUNT , ...) | kmalloc( - sizeof(unsigned char) * COUNT + COUNT , ...) ) // 2-factor product with sizeof(type/expression) and identifier or constant. @@ type TYPE; expression THING; identifier COUNT_ID; constant COUNT_CONST; @@ ( - kmalloc + kmalloc_array ( - sizeof(TYPE) * (COUNT_ID) + COUNT_ID, sizeof(TYPE) , ...) | - kmalloc + kmalloc_array ( - sizeof(TYPE) * COUNT_ID + COUNT_ID, sizeof(TYPE) , ...) | - kmalloc + kmalloc_array ( - sizeof(TYPE) * (COUNT_CONST) + COUNT_CONST, sizeof(TYPE) , ...) | - kmalloc + kmalloc_array ( - sizeof(TYPE) * COUNT_CONST + COUNT_CONST, sizeof(TYPE) , ...) | - kmalloc + kmalloc_array ( - sizeof(THING) * (COUNT_ID) + COUNT_ID, sizeof(THING) , ...) | - kmalloc + kmalloc_array ( - sizeof(THING) * COUNT_ID + COUNT_ID, sizeof(THING) , ...) | - kmalloc + kmalloc_array ( - sizeof(THING) * (COUNT_CONST) + COUNT_CONST, sizeof(THING) , ...) | - kmalloc + kmalloc_array ( - sizeof(THING) * COUNT_CONST + COUNT_CONST, sizeof(THING) , ...) ) // 2-factor product, only identifiers. @@ identifier SIZE, COUNT; @@ - kmalloc + kmalloc_array ( - SIZE * COUNT + COUNT, SIZE , ...) // 3-factor product with 1 sizeof(type) or sizeof(expression), with // redundant parens removed. @@ expression THING; identifier STRIDE, COUNT; type TYPE; @@ ( kmalloc( - sizeof(TYPE) * (COUNT) * (STRIDE) + array3_size(COUNT, STRIDE, sizeof(TYPE)) , ...) | kmalloc( - sizeof(TYPE) * (COUNT) * STRIDE + array3_size(COUNT, STRIDE, sizeof(TYPE)) , ...) | kmalloc( - sizeof(TYPE) * COUNT * (STRIDE) + array3_size(COUNT, STRIDE, sizeof(TYPE)) , ...) | kmalloc( - sizeof(TYPE) * COUNT * STRIDE + array3_size(COUNT, STRIDE, sizeof(TYPE)) , ...) | kmalloc( - sizeof(THING) * (COUNT) * (STRIDE) + array3_size(COUNT, STRIDE, sizeof(THING)) , ...) | kmalloc( - sizeof(THING) * (COUNT) * STRIDE + array3_size(COUNT, STRIDE, sizeof(THING)) , ...) | kmalloc( - sizeof(THING) * COUNT * (STRIDE) + array3_size(COUNT, STRIDE, sizeof(THING)) , ...) | kmalloc( - sizeof(THING) * COUNT * STRIDE + array3_size(COUNT, STRIDE, sizeof(THING)) , ...) ) // 3-factor product with 2 sizeof(variable), with redundant parens removed. @@ expression THING1, THING2; identifier COUNT; type TYPE1, TYPE2; @@ ( kmalloc( - sizeof(TYPE1) * sizeof(TYPE2) * COUNT + array3_size(COUNT, sizeof(TYPE1), sizeof(TYPE2)) , ...) | kmalloc( - sizeof(TYPE1) * sizeof(THING2) * (COUNT) + array3_size(COUNT, sizeof(TYPE1), sizeof(TYPE2)) , ...) | kmalloc( - sizeof(THING1) * sizeof(THING2) * COUNT + array3_size(COUNT, sizeof(THING1), sizeof(THING2)) , ...) | kmalloc( - sizeof(THING1) * sizeof(THING2) * (COUNT) + array3_size(COUNT, sizeof(THING1), sizeof(THING2)) , ...) | kmalloc( - sizeof(TYPE1) * sizeof(THING2) * COUNT + array3_size(COUNT, sizeof(TYPE1), sizeof(THING2)) , ...) | kmalloc( - sizeof(TYPE1) * sizeof(THING2) * (COUNT) + array3_size(COUNT, sizeof(TYPE1), sizeof(THING2)) , ...) ) // 3-factor product, only identifiers, with redundant parens removed. @@ identifier STRIDE, SIZE, COUNT; @@ ( kmalloc( - (COUNT) * STRIDE * SIZE + array3_size(COUNT, STRIDE, SIZE) , ...) | kmalloc( - COUNT * (STRIDE) * SIZE + array3_size(COUNT, STRIDE, SIZE) , ...) | kmalloc( - COUNT * STRIDE * (SIZE) + array3_size(COUNT, STRIDE, SIZE) , ...) | kmalloc( - (COUNT) * (STRIDE) * SIZE + array3_size(COUNT, STRIDE, SIZE) , ...) | kmalloc( - COUNT * (STRIDE) * (SIZE) + array3_size(COUNT, STRIDE, SIZE) , ...) | kmalloc( - (COUNT) * STRIDE * (SIZE) + array3_size(COUNT, STRIDE, SIZE) , ...) | kmalloc( - (COUNT) * (STRIDE) * (SIZE) + array3_size(COUNT, STRIDE, SIZE) , ...) | kmalloc( - COUNT * STRIDE * SIZE + array3_size(COUNT, STRIDE, SIZE) , ...) ) // Any remaining multi-factor products, first at least 3-factor products, // when they're not all constants... @@ expression E1, E2, E3; constant C1, C2, C3; @@ ( kmalloc(C1 * C2 * C3, ...) | kmalloc( - (E1) * E2 * E3 + array3_size(E1, E2, E3) , ...) | kmalloc( - (E1) * (E2) * E3 + array3_size(E1, E2, E3) , ...) | kmalloc( - (E1) * (E2) * (E3) + array3_size(E1, E2, E3) , ...) | kmalloc( - E1 * E2 * E3 + array3_size(E1, E2, E3) , ...) ) // And then all remaining 2 factors products when they're not all constants, // keeping sizeof() as the second factor argument. @@ expression THING, E1, E2; type TYPE; constant C1, C2, C3; @@ ( kmalloc(sizeof(THING) * C2, ...) | kmalloc(sizeof(TYPE) * C2, ...) | kmalloc(C1 * C2 * C3, ...) | kmalloc(C1 * C2, ...) | - kmalloc + kmalloc_array ( - sizeof(TYPE) * (E2) + E2, sizeof(TYPE) , ...) | - kmalloc + kmalloc_array ( - sizeof(TYPE) * E2 + E2, sizeof(TYPE) , ...) | - kmalloc + kmalloc_array ( - sizeof(THING) * (E2) + E2, sizeof(THING) , ...) | - kmalloc + kmalloc_array ( - sizeof(THING) * E2 + E2, sizeof(THING) , ...) | - kmalloc + kmalloc_array ( - (E1) * E2 + E1, E2 , ...) | - kmalloc + kmalloc_array ( - (E1) * (E2) + E1, E2 , ...) | - kmalloc + kmalloc_array ( - E1 * E2 + E1, E2 , ...) ) Signed-off-by: Kees Cook <keescook@chromium.org>
2018-06-13 04:55:00 +08:00
store->filemap = kmalloc_array(num_pages, sizeof(struct page *),
GFP_KERNEL);
if (!store->filemap)
return -ENOMEM;
if (with_super && !store->sb_page) {
store->sb_page = alloc_page(GFP_KERNEL|__GFP_ZERO);
if (store->sb_page == NULL)
return -ENOMEM;
}
pnum = 0;
if (store->sb_page) {
store->filemap[0] = store->sb_page;
pnum = 1;
store->sb_page->index = offset;
}
for ( ; pnum < num_pages; pnum++) {
store->filemap[pnum] = alloc_page(GFP_KERNEL|__GFP_ZERO);
if (!store->filemap[pnum]) {
store->file_pages = pnum;
return -ENOMEM;
}
store->filemap[pnum]->index = pnum + offset;
}
store->file_pages = pnum;
/* We need 4 bits per page, rounded up to a multiple
* of sizeof(unsigned long) */
store->filemap_attr = kzalloc(
roundup(DIV_ROUND_UP(num_pages*4, 8), sizeof(unsigned long)),
GFP_KERNEL);
if (!store->filemap_attr)
return -ENOMEM;
store->bytes = bytes;
return 0;
}
static void md_bitmap_file_unmap(struct bitmap_storage *store)
{
struct page **map, *sb_page;
int pages;
struct file *file;
file = store->file;
map = store->filemap;
pages = store->file_pages;
sb_page = store->sb_page;
while (pages--)
if (map[pages] != sb_page) /* 0 is sb_page, release it below */
[PATCH] md/bitmap: change md/bitmap file handling to use bmap to file blocks If md is asked to store a bitmap in a file, it tries to hold onto the page cache pages for that file, manipulate them directly, and call a cocktail of operations to write the file out. I don't believe this is a supportable approach. This patch changes the approach to use the same approach as swap files. i.e. bmap is used to enumerate all the block address of parts of the file and we write directly to those blocks of the device. swapfile only uses parts of the file that provide a full pages at contiguous addresses. We don't have that luxury so we have to cope with pages that are non-contiguous in storage. To handle this we attach buffers to each page, and store the addresses in those buffers. With this approach the pagecache may contain data which is inconsistent with what is on disk. To alleviate the problems this can cause, md invalidates the pagecache when releasing the file. If the file is to be examined while the array is active (a non-critical but occasionally useful function), O_DIRECT io must be used. And new version of mdadm will have support for this. This approach simplifies a lot of code: - we no longer need to keep a list of pages which we need to wait for, as the b_endio function can keep track of how many outstanding writes there are. This saves a mempool. - -EAGAIN returns from write_page are no longer possible (not sure if they ever were actually). Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-26 15:27:48 +08:00
free_buffers(map[pages]);
kfree(map);
kfree(store->filemap_attr);
[PATCH] md/bitmap: change md/bitmap file handling to use bmap to file blocks If md is asked to store a bitmap in a file, it tries to hold onto the page cache pages for that file, manipulate them directly, and call a cocktail of operations to write the file out. I don't believe this is a supportable approach. This patch changes the approach to use the same approach as swap files. i.e. bmap is used to enumerate all the block address of parts of the file and we write directly to those blocks of the device. swapfile only uses parts of the file that provide a full pages at contiguous addresses. We don't have that luxury so we have to cope with pages that are non-contiguous in storage. To handle this we attach buffers to each page, and store the addresses in those buffers. With this approach the pagecache may contain data which is inconsistent with what is on disk. To alleviate the problems this can cause, md invalidates the pagecache when releasing the file. If the file is to be examined while the array is active (a non-critical but occasionally useful function), O_DIRECT io must be used. And new version of mdadm will have support for this. This approach simplifies a lot of code: - we no longer need to keep a list of pages which we need to wait for, as the b_endio function can keep track of how many outstanding writes there are. This saves a mempool. - -EAGAIN returns from write_page are no longer possible (not sure if they ever were actually). Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-26 15:27:48 +08:00
if (sb_page)
free_buffers(sb_page);
[PATCH] md/bitmap: change md/bitmap file handling to use bmap to file blocks If md is asked to store a bitmap in a file, it tries to hold onto the page cache pages for that file, manipulate them directly, and call a cocktail of operations to write the file out. I don't believe this is a supportable approach. This patch changes the approach to use the same approach as swap files. i.e. bmap is used to enumerate all the block address of parts of the file and we write directly to those blocks of the device. swapfile only uses parts of the file that provide a full pages at contiguous addresses. We don't have that luxury so we have to cope with pages that are non-contiguous in storage. To handle this we attach buffers to each page, and store the addresses in those buffers. With this approach the pagecache may contain data which is inconsistent with what is on disk. To alleviate the problems this can cause, md invalidates the pagecache when releasing the file. If the file is to be examined while the array is active (a non-critical but occasionally useful function), O_DIRECT io must be used. And new version of mdadm will have support for this. This approach simplifies a lot of code: - we no longer need to keep a list of pages which we need to wait for, as the b_endio function can keep track of how many outstanding writes there are. This saves a mempool. - -EAGAIN returns from write_page are no longer possible (not sure if they ever were actually). Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-26 15:27:48 +08:00
if (file) {
struct inode *inode = file_inode(file);
invalidate_mapping_pages(inode->i_mapping, 0, -1);
fput(file);
[PATCH] md/bitmap: change md/bitmap file handling to use bmap to file blocks If md is asked to store a bitmap in a file, it tries to hold onto the page cache pages for that file, manipulate them directly, and call a cocktail of operations to write the file out. I don't believe this is a supportable approach. This patch changes the approach to use the same approach as swap files. i.e. bmap is used to enumerate all the block address of parts of the file and we write directly to those blocks of the device. swapfile only uses parts of the file that provide a full pages at contiguous addresses. We don't have that luxury so we have to cope with pages that are non-contiguous in storage. To handle this we attach buffers to each page, and store the addresses in those buffers. With this approach the pagecache may contain data which is inconsistent with what is on disk. To alleviate the problems this can cause, md invalidates the pagecache when releasing the file. If the file is to be examined while the array is active (a non-critical but occasionally useful function), O_DIRECT io must be used. And new version of mdadm will have support for this. This approach simplifies a lot of code: - we no longer need to keep a list of pages which we need to wait for, as the b_endio function can keep track of how many outstanding writes there are. This saves a mempool. - -EAGAIN returns from write_page are no longer possible (not sure if they ever were actually). Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-26 15:27:48 +08:00
}
}
/*
* bitmap_file_kick - if an error occurs while manipulating the bitmap file
* then it is no longer reliable, so we stop using it and we mark the file
* as failed in the superblock
*/
static void md_bitmap_file_kick(struct bitmap *bitmap)
{
char *path, *ptr = NULL;
if (!test_and_set_bit(BITMAP_STALE, &bitmap->flags)) {
md_bitmap_update_sb(bitmap);
if (bitmap->storage.file) {
path = kmalloc(PAGE_SIZE, GFP_KERNEL);
if (path)
ptr = file_path(bitmap->storage.file,
path, PAGE_SIZE);
pr_warn("%s: kicking failed bitmap file %s from array!\n",
bmname(bitmap), IS_ERR(ptr) ? "" : ptr);
kfree(path);
} else
pr_warn("%s: disabling internal bitmap due to errors\n",
bmname(bitmap));
}
}
enum bitmap_page_attr {
BITMAP_PAGE_DIRTY = 0, /* there are set bits that need to be synced */
BITMAP_PAGE_PENDING = 1, /* there are bits that are being cleaned.
* i.e. counter is 1 or 2. */
BITMAP_PAGE_NEEDWRITE = 2, /* there are cleared bits that need to be synced */
};
static inline void set_page_attr(struct bitmap *bitmap, int pnum,
enum bitmap_page_attr attr)
{
set_bit((pnum<<2) + attr, bitmap->storage.filemap_attr);
}
static inline void clear_page_attr(struct bitmap *bitmap, int pnum,
enum bitmap_page_attr attr)
{
clear_bit((pnum<<2) + attr, bitmap->storage.filemap_attr);
}
static inline int test_page_attr(struct bitmap *bitmap, int pnum,
enum bitmap_page_attr attr)
{
return test_bit((pnum<<2) + attr, bitmap->storage.filemap_attr);
}
static inline int test_and_clear_page_attr(struct bitmap *bitmap, int pnum,
enum bitmap_page_attr attr)
{
return test_and_clear_bit((pnum<<2) + attr,
bitmap->storage.filemap_attr);
}
/*
* bitmap_file_set_bit -- called before performing a write to the md device
* to set (and eventually sync) a particular bit in the bitmap file
*
* we set the bit immediately, then we record the page number so that
* when an unplug occurs, we can flush the dirty pages out to disk
*/
static void md_bitmap_file_set_bit(struct bitmap *bitmap, sector_t block)
{
unsigned long bit;
struct page *page;
void *kaddr;
unsigned long chunk = block >> bitmap->counts.chunkshift;
struct bitmap_storage *store = &bitmap->storage;
unsigned long node_offset = 0;
if (mddev_is_clustered(bitmap->mddev))
node_offset = bitmap->cluster_slot * store->file_pages;
page = filemap_get_page(&bitmap->storage, chunk);
if (!page)
return;
bit = file_page_offset(&bitmap->storage, chunk);
/* set the bit */
kaddr = kmap_atomic(page);
if (test_bit(BITMAP_HOSTENDIAN, &bitmap->flags))
set_bit(bit, kaddr);
else
set_bit_le(bit, kaddr);
kunmap_atomic(kaddr);
pr_debug("set file bit %lu page %lu\n", bit, page->index);
/* record page number so it gets flushed to disk when unplug occurs */
set_page_attr(bitmap, page->index - node_offset, BITMAP_PAGE_DIRTY);
}
static void md_bitmap_file_clear_bit(struct bitmap *bitmap, sector_t block)
{
unsigned long bit;
struct page *page;
void *paddr;
unsigned long chunk = block >> bitmap->counts.chunkshift;
struct bitmap_storage *store = &bitmap->storage;
unsigned long node_offset = 0;
if (mddev_is_clustered(bitmap->mddev))
node_offset = bitmap->cluster_slot * store->file_pages;
page = filemap_get_page(&bitmap->storage, chunk);
if (!page)
return;
bit = file_page_offset(&bitmap->storage, chunk);
paddr = kmap_atomic(page);
if (test_bit(BITMAP_HOSTENDIAN, &bitmap->flags))
clear_bit(bit, paddr);
else
clear_bit_le(bit, paddr);
kunmap_atomic(paddr);
if (!test_page_attr(bitmap, page->index - node_offset, BITMAP_PAGE_NEEDWRITE)) {
set_page_attr(bitmap, page->index - node_offset, BITMAP_PAGE_PENDING);
bitmap->allclean = 0;
}
}
static int md_bitmap_file_test_bit(struct bitmap *bitmap, sector_t block)
{
unsigned long bit;
struct page *page;
void *paddr;
unsigned long chunk = block >> bitmap->counts.chunkshift;
int set = 0;
page = filemap_get_page(&bitmap->storage, chunk);
if (!page)
return -EINVAL;
bit = file_page_offset(&bitmap->storage, chunk);
paddr = kmap_atomic(page);
if (test_bit(BITMAP_HOSTENDIAN, &bitmap->flags))
set = test_bit(bit, paddr);
else
set = test_bit_le(bit, paddr);
kunmap_atomic(paddr);
return set;
}
/* 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 */
void md_bitmap_unplug(struct bitmap *bitmap)
{
unsigned long i;
int dirty, need_write;
int writing = 0;
if (!bitmap || !bitmap->storage.filemap ||
test_bit(BITMAP_STALE, &bitmap->flags))
return;
/* look at each page to see if there are any set bits that need to be
* flushed out to disk */
for (i = 0; i < bitmap->storage.file_pages; i++) {
dirty = test_and_clear_page_attr(bitmap, i, BITMAP_PAGE_DIRTY);
need_write = test_and_clear_page_attr(bitmap, i,
BITMAP_PAGE_NEEDWRITE);
if (dirty || need_write) {
if (!writing) {
md_bitmap_wait_writes(bitmap);
if (bitmap->mddev->queue)
blk_add_trace_msg(bitmap->mddev->queue,
"md bitmap_unplug");
}
clear_page_attr(bitmap, i, BITMAP_PAGE_PENDING);
write_page(bitmap, bitmap->storage.filemap[i], 0);
writing = 1;
}
}
if (writing)
md_bitmap_wait_writes(bitmap);
if (test_bit(BITMAP_WRITE_ERROR, &bitmap->flags))
md_bitmap_file_kick(bitmap);
}
EXPORT_SYMBOL(md_bitmap_unplug);
static void md_bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset, int needed);
/* * bitmap_init_from_disk -- called at bitmap_create time to initialize
* the in-memory bitmap from the on-disk bitmap -- also, sets up the
* memory mapping of the bitmap file
* Special cases:
* if there's no bitmap file, or if the bitmap file had been
* previously kicked from the array, we mark all the bits as
* 1's in order to cause a full resync.
*
* We ignore all bits for sectors that end earlier than 'start'.
* This is used when reading an out-of-date bitmap...
*/
static int md_bitmap_init_from_disk(struct bitmap *bitmap, sector_t start)
{
unsigned long i, chunks, index, oldindex, bit, node_offset = 0;
struct page *page = NULL;
unsigned long bit_cnt = 0;
struct file *file;
unsigned long offset;
int outofdate;
int ret = -ENOSPC;
void *paddr;
struct bitmap_storage *store = &bitmap->storage;
chunks = bitmap->counts.chunks;
file = store->file;
if (!file && !bitmap->mddev->bitmap_info.offset) {
/* No permanent bitmap - fill with '1s'. */
store->filemap = NULL;
store->file_pages = 0;
for (i = 0; i < chunks ; i++) {
/* if the disk bit is set, set the memory bit */
int needed = ((sector_t)(i+1) << (bitmap->counts.chunkshift)
>= start);
md_bitmap_set_memory_bits(bitmap,
(sector_t)i << bitmap->counts.chunkshift,
needed);
}
return 0;
}
outofdate = test_bit(BITMAP_STALE, &bitmap->flags);
if (outofdate)
pr_warn("%s: bitmap file is out of date, doing full recovery\n", bmname(bitmap));
if (file && i_size_read(file->f_mapping->host) < store->bytes) {
pr_warn("%s: bitmap file too short %lu < %lu\n",
bmname(bitmap),
(unsigned long) i_size_read(file->f_mapping->host),
store->bytes);
goto err;
}
oldindex = ~0L;
offset = 0;
if (!bitmap->mddev->bitmap_info.external)
offset = sizeof(bitmap_super_t);
if (mddev_is_clustered(bitmap->mddev))
node_offset = bitmap->cluster_slot * (DIV_ROUND_UP(store->bytes, PAGE_SIZE));
for (i = 0; i < chunks; i++) {
int b;
index = file_page_index(&bitmap->storage, i);
bit = file_page_offset(&bitmap->storage, i);
if (index != oldindex) { /* this is a new page, read it in */
[PATCH] md/bitmap: change md/bitmap file handling to use bmap to file blocks If md is asked to store a bitmap in a file, it tries to hold onto the page cache pages for that file, manipulate them directly, and call a cocktail of operations to write the file out. I don't believe this is a supportable approach. This patch changes the approach to use the same approach as swap files. i.e. bmap is used to enumerate all the block address of parts of the file and we write directly to those blocks of the device. swapfile only uses parts of the file that provide a full pages at contiguous addresses. We don't have that luxury so we have to cope with pages that are non-contiguous in storage. To handle this we attach buffers to each page, and store the addresses in those buffers. With this approach the pagecache may contain data which is inconsistent with what is on disk. To alleviate the problems this can cause, md invalidates the pagecache when releasing the file. If the file is to be examined while the array is active (a non-critical but occasionally useful function), O_DIRECT io must be used. And new version of mdadm will have support for this. This approach simplifies a lot of code: - we no longer need to keep a list of pages which we need to wait for, as the b_endio function can keep track of how many outstanding writes there are. This saves a mempool. - -EAGAIN returns from write_page are no longer possible (not sure if they ever were actually). Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-26 15:27:48 +08:00
int count;
/* unmap the old page, we're done with it */
if (index == store->file_pages-1)
count = store->bytes - index * PAGE_SIZE;
[PATCH] md/bitmap: change md/bitmap file handling to use bmap to file blocks If md is asked to store a bitmap in a file, it tries to hold onto the page cache pages for that file, manipulate them directly, and call a cocktail of operations to write the file out. I don't believe this is a supportable approach. This patch changes the approach to use the same approach as swap files. i.e. bmap is used to enumerate all the block address of parts of the file and we write directly to those blocks of the device. swapfile only uses parts of the file that provide a full pages at contiguous addresses. We don't have that luxury so we have to cope with pages that are non-contiguous in storage. To handle this we attach buffers to each page, and store the addresses in those buffers. With this approach the pagecache may contain data which is inconsistent with what is on disk. To alleviate the problems this can cause, md invalidates the pagecache when releasing the file. If the file is to be examined while the array is active (a non-critical but occasionally useful function), O_DIRECT io must be used. And new version of mdadm will have support for this. This approach simplifies a lot of code: - we no longer need to keep a list of pages which we need to wait for, as the b_endio function can keep track of how many outstanding writes there are. This saves a mempool. - -EAGAIN returns from write_page are no longer possible (not sure if they ever were actually). Signed-off-by: Neil Brown <neilb@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-06-26 15:27:48 +08:00
else
count = PAGE_SIZE;
page = store->filemap[index];
if (file)
ret = read_page(file, index, bitmap,
count, page);
else
ret = read_sb_page(
bitmap->mddev,
bitmap->mddev->bitmap_info.offset,
page,
index + node_offset, count);
if (ret)
goto err;
oldindex = index;
if (outofdate) {
/*
* if bitmap is out of date, dirty the
* whole page and write it out
*/
paddr = kmap_atomic(page);
memset(paddr + offset, 0xff,
PAGE_SIZE - offset);
kunmap_atomic(paddr);
write_page(bitmap, page, 1);
ret = -EIO;
if (test_bit(BITMAP_WRITE_ERROR,
&bitmap->flags))
goto err;
}
}
paddr = kmap_atomic(page);
if (test_bit(BITMAP_HOSTENDIAN, &bitmap->flags))
b = test_bit(bit, paddr);
else
b = test_bit_le(bit, paddr);
kunmap_atomic(paddr);
if (b) {
/* if the disk bit is set, set the memory bit */
int needed = ((sector_t)(i+1) << bitmap->counts.chunkshift
>= start);
md_bitmap_set_memory_bits(bitmap,
(sector_t)i << bitmap->counts.chunkshift,
needed);
bit_cnt++;
}
offset = 0;
}
pr_debug("%s: bitmap initialized from disk: read %lu pages, set %lu of %lu bits\n",
bmname(bitmap), store->file_pages,
bit_cnt, chunks);
return 0;
err:
pr_warn("%s: bitmap initialisation failed: %d\n",
bmname(bitmap), ret);
return ret;
}
void md_bitmap_write_all(struct bitmap *bitmap)
{
/* We don't actually write all bitmap blocks here,
* just flag them as needing to be written
*/
int i;
if (!bitmap || !bitmap->storage.filemap)
return;
if (bitmap->storage.file)
/* Only one copy, so nothing needed */
return;
for (i = 0; i < bitmap->storage.file_pages; i++)
set_page_attr(bitmap, i,
BITMAP_PAGE_NEEDWRITE);
bitmap->allclean = 0;
}
static void md_bitmap_count_page(struct bitmap_counts *bitmap,
sector_t offset, int inc)
{
sector_t chunk = offset >> bitmap->chunkshift;
unsigned long page = chunk >> PAGE_COUNTER_SHIFT;
bitmap->bp[page].count += inc;
md_bitmap_checkfree(bitmap, page);
}
static void md_bitmap_set_pending(struct bitmap_counts *bitmap, sector_t offset)
{
sector_t chunk = offset >> bitmap->chunkshift;
unsigned long page = chunk >> PAGE_COUNTER_SHIFT;
struct bitmap_page *bp = &bitmap->bp[page];
if (!bp->pending)
bp->pending = 1;
}
static bitmap_counter_t *md_bitmap_get_counter(struct bitmap_counts *bitmap,
sector_t offset, sector_t *blocks,
int create);
/*
* bitmap daemon -- periodically wakes up to clean bits and flush pages
* out to disk
*/
void md_bitmap_daemon_work(struct mddev *mddev)
{
struct bitmap *bitmap;
unsigned long j;
unsigned long nextpage;
sector_t blocks;
struct bitmap_counts *counts;
/* Use a mutex to guard daemon_work against
* bitmap_destroy.
*/
mutex_lock(&mddev->bitmap_info.mutex);
bitmap = mddev->bitmap;
if (bitmap == NULL) {
mutex_unlock(&mddev->bitmap_info.mutex);
return;
}
if (time_before(jiffies, bitmap->daemon_lastrun
+ mddev->bitmap_info.daemon_sleep))
goto done;
bitmap->daemon_lastrun = jiffies;
if (bitmap->allclean) {
mddev->thread->timeout = MAX_SCHEDULE_TIMEOUT;
goto done;
}
bitmap->allclean = 1;
if (bitmap->mddev->queue)
blk_add_trace_msg(bitmap->mddev->queue,
"md bitmap_daemon_work");
/* Any file-page which is PENDING now needs to be written.
* So set NEEDWRITE now, then after we make any last-minute changes
* we will write it.
*/
for (j = 0; j < bitmap->storage.file_pages; j++)
if (test_and_clear_page_attr(bitmap, j,
BITMAP_PAGE_PENDING))
set_page_attr(bitmap, j,
BITMAP_PAGE_NEEDWRITE);
if (bitmap->need_sync &&
mddev->bitmap_info.external == 0) {
/* Arrange for superblock update as well as
* other changes */
bitmap_super_t *sb;
bitmap->need_sync = 0;
if (bitmap->storage.filemap) {
sb = kmap_atomic(bitmap->storage.sb_page);
sb->events_cleared =
cpu_to_le64(bitmap->events_cleared);
kunmap_atomic(sb);
set_page_attr(bitmap, 0,
BITMAP_PAGE_NEEDWRITE);
}
}
/* Now look at the bitmap counters and if any are '2' or '1',
* decrement and handle accordingly.
*/
counts = &bitmap->counts;
spin_lock_irq(&counts->lock);
nextpage = 0;
for (j = 0; j < counts->chunks; j++) {
bitmap_counter_t *bmc;
sector_t block = (sector_t)j << counts->chunkshift;
if (j == nextpage) {
nextpage += PAGE_COUNTER_RATIO;
if (!counts->bp[j >> PAGE_COUNTER_SHIFT].pending) {
j |= PAGE_COUNTER_MASK;
continue;
}
counts->bp[j >> PAGE_COUNTER_SHIFT].pending = 0;
}
bmc = md_bitmap_get_counter(counts, block, &blocks, 0);
if (!bmc) {
j |= PAGE_COUNTER_MASK;
continue;
}
if (*bmc == 1 && !bitmap->need_sync) {
/* We can clear the bit */
*bmc = 0;
md_bitmap_count_page(counts, block, -1);
md_bitmap_file_clear_bit(bitmap, block);
} else if (*bmc && *bmc <= 2) {
*bmc = 1;
md_bitmap_set_pending(counts, block);
bitmap->allclean = 0;
}
}
spin_unlock_irq(&counts->lock);
md_bitmap_wait_writes(bitmap);
/* Now start writeout on any page in NEEDWRITE that isn't DIRTY.
* DIRTY pages need to be written by bitmap_unplug so it can wait
* for them.
* If we find any DIRTY page we stop there and let bitmap_unplug
* handle all the rest. This is important in the case where
* the first blocking holds the superblock and it has been updated.
* We mustn't write any other blocks before the superblock.
*/
for (j = 0;
j < bitmap->storage.file_pages
&& !test_bit(BITMAP_STALE, &bitmap->flags);
j++) {
if (test_page_attr(bitmap, j,
BITMAP_PAGE_DIRTY))
/* bitmap_unplug will handle the rest */
break;
if (bitmap->storage.filemap &&
test_and_clear_page_attr(bitmap, j,
BITMAP_PAGE_NEEDWRITE)) {
write_page(bitmap, bitmap->storage.filemap[j], 0);
}
}
done:
if (bitmap->allclean == 0)
mddev->thread->timeout =
mddev->bitmap_info.daemon_sleep;
mutex_unlock(&mddev->bitmap_info.mutex);
}
static bitmap_counter_t *md_bitmap_get_counter(struct bitmap_counts *bitmap,
sector_t offset, sector_t *blocks,
int create)
__releases(bitmap->lock)
__acquires(bitmap->lock)
{
/* If 'create', we might release the lock and reclaim it.
* The lock must have been taken with interrupts enabled.
* If !create, we don't release the lock.
*/
sector_t chunk = offset >> bitmap->chunkshift;
unsigned long page = chunk >> PAGE_COUNTER_SHIFT;
unsigned long pageoff = (chunk & PAGE_COUNTER_MASK) << COUNTER_BYTE_SHIFT;
sector_t csize;
int err;
err = md_bitmap_checkpage(bitmap, page, create, 0);
if (bitmap->bp[page].hijacked ||
bitmap->bp[page].map == NULL)
csize = ((sector_t)1) << (bitmap->chunkshift +
PAGE_COUNTER_SHIFT);
else
csize = ((sector_t)1) << bitmap->chunkshift;
*blocks = csize - (offset & (csize - 1));
if (err < 0)
return NULL;
/* now locked ... */
if (bitmap->bp[page].hijacked) { /* hijacked pointer */
/* should we use the first or second counter field
* of the hijacked pointer? */
int hi = (pageoff > PAGE_COUNTER_MASK);
return &((bitmap_counter_t *)
&bitmap->bp[page].map)[hi];
} else /* page is allocated */
return (bitmap_counter_t *)
&(bitmap->bp[page].map[pageoff]);
}
int md_bitmap_startwrite(struct bitmap *bitmap, sector_t offset, unsigned long sectors, int behind)
{
if (!bitmap)
return 0;
if (behind) {
int bw;
atomic_inc(&bitmap->behind_writes);
bw = atomic_read(&bitmap->behind_writes);
if (bw > bitmap->behind_writes_used)
bitmap->behind_writes_used = bw;
pr_debug("inc write-behind count %d/%lu\n",
bw, bitmap->mddev->bitmap_info.max_write_behind);
}
while (sectors) {
sector_t blocks;
bitmap_counter_t *bmc;
spin_lock_irq(&bitmap->counts.lock);
bmc = md_bitmap_get_counter(&bitmap->counts, offset, &blocks, 1);
if (!bmc) {
spin_unlock_irq(&bitmap->counts.lock);
return 0;
}
if (unlikely(COUNTER(*bmc) == COUNTER_MAX)) {
DEFINE_WAIT(__wait);
/* note that it is safe to do the prepare_to_wait
* after the test as long as we do it before dropping
* the spinlock.
*/
prepare_to_wait(&bitmap->overflow_wait, &__wait,
TASK_UNINTERRUPTIBLE);
spin_unlock_irq(&bitmap->counts.lock);
schedule();
finish_wait(&bitmap->overflow_wait, &__wait);
continue;
}
switch (*bmc) {
case 0:
md_bitmap_file_set_bit(bitmap, offset);
md_bitmap_count_page(&bitmap->counts, offset, 1);
fallthrough;
case 1:
*bmc = 2;
}
(*bmc)++;
spin_unlock_irq(&bitmap->counts.lock);
offset += blocks;
if (sectors > blocks)
sectors -= blocks;
else
sectors = 0;
}
return 0;
}
EXPORT_SYMBOL(md_bitmap_startwrite);
void md_bitmap_endwrite(struct bitmap *bitmap, sector_t offset,
unsigned long sectors, int success, int behind)
{
if (!bitmap)
return;
if (behind) {
if (atomic_dec_and_test(&bitmap->behind_writes))
wake_up(&bitmap->behind_wait);
pr_debug("dec write-behind count %d/%lu\n",
atomic_read(&bitmap->behind_writes),
bitmap->mddev->bitmap_info.max_write_behind);
}
while (sectors) {
sector_t blocks;
unsigned long flags;
bitmap_counter_t *bmc;
spin_lock_irqsave(&bitmap->counts.lock, flags);
bmc = md_bitmap_get_counter(&bitmap->counts, offset, &blocks, 0);
if (!bmc) {
spin_unlock_irqrestore(&bitmap->counts.lock, flags);
return;
}
if (success && !bitmap->mddev->degraded &&
bitmap->events_cleared < bitmap->mddev->events) {
bitmap->events_cleared = bitmap->mddev->events;
bitmap->need_sync = 1;
sysfs_notify_dirent_safe(bitmap->sysfs_can_clear);
}
if (!success && !NEEDED(*bmc))
*bmc |= NEEDED_MASK;
if (COUNTER(*bmc) == COUNTER_MAX)
wake_up(&bitmap->overflow_wait);
(*bmc)--;
if (*bmc <= 2) {
md_bitmap_set_pending(&bitmap->counts, offset);
bitmap->allclean = 0;
}
spin_unlock_irqrestore(&bitmap->counts.lock, flags);
offset += blocks;
if (sectors > blocks)
sectors -= blocks;
else
sectors = 0;
}
}
EXPORT_SYMBOL(md_bitmap_endwrite);
static int __bitmap_start_sync(struct bitmap *bitmap, sector_t offset, sector_t *blocks,
int degraded)
{
bitmap_counter_t *bmc;
int rv;
if (bitmap == NULL) {/* FIXME or bitmap set as 'failed' */
*blocks = 1024;
return 1; /* always resync if no bitmap */
}
spin_lock_irq(&bitmap->counts.lock);
bmc = md_bitmap_get_counter(&bitmap->counts, offset, blocks, 0);
rv = 0;
if (bmc) {
/* locked */
if (RESYNC(*bmc))
rv = 1;
else if (NEEDED(*bmc)) {
rv = 1;
if (!degraded) { /* don't set/clear bits if degraded */
*bmc |= RESYNC_MASK;
*bmc &= ~NEEDED_MASK;
}
}
}
spin_unlock_irq(&bitmap->counts.lock);
return rv;
}
int md_bitmap_start_sync(struct bitmap *bitmap, sector_t offset, sector_t *blocks,
int degraded)
{
/* bitmap_start_sync must always report on multiples of whole
* pages, otherwise resync (which is very PAGE_SIZE based) will
* get confused.
* So call __bitmap_start_sync repeatedly (if needed) until
* At least PAGE_SIZE>>9 blocks are covered.
* Return the 'or' of the result.
*/
int rv = 0;
sector_t blocks1;
*blocks = 0;
while (*blocks < (PAGE_SIZE>>9)) {
rv |= __bitmap_start_sync(bitmap, offset,
&blocks1, degraded);
offset += blocks1;
*blocks += blocks1;
}
return rv;
}
EXPORT_SYMBOL(md_bitmap_start_sync);
void md_bitmap_end_sync(struct bitmap *bitmap, sector_t offset, sector_t *blocks, int aborted)
{
bitmap_counter_t *bmc;
unsigned long flags;
if (bitmap == NULL) {
*blocks = 1024;
return;
}
spin_lock_irqsave(&bitmap->counts.lock, flags);
bmc = md_bitmap_get_counter(&bitmap->counts, offset, blocks, 0);
if (bmc == NULL)
goto unlock;
/* locked */
if (RESYNC(*bmc)) {
*bmc &= ~RESYNC_MASK;
if (!NEEDED(*bmc) && aborted)
*bmc |= NEEDED_MASK;
else {
if (*bmc <= 2) {
md_bitmap_set_pending(&bitmap->counts, offset);
bitmap->allclean = 0;
}
}
}
unlock:
spin_unlock_irqrestore(&bitmap->counts.lock, flags);
}
EXPORT_SYMBOL(md_bitmap_end_sync);
void md_bitmap_close_sync(struct bitmap *bitmap)
{
/* Sync has finished, and any bitmap chunks that weren't synced
* properly have been aborted. It remains to us to clear the
* RESYNC bit wherever it is still on
*/
sector_t sector = 0;
sector_t blocks;
if (!bitmap)
return;
while (sector < bitmap->mddev->resync_max_sectors) {
md_bitmap_end_sync(bitmap, sector, &blocks, 0);
sector += blocks;
}
}
EXPORT_SYMBOL(md_bitmap_close_sync);
void md_bitmap_cond_end_sync(struct bitmap *bitmap, sector_t sector, bool force)
{
sector_t s = 0;
sector_t blocks;
if (!bitmap)
return;
if (sector == 0) {
bitmap->last_end_sync = jiffies;
return;
}
if (!force && time_before(jiffies, (bitmap->last_end_sync
+ bitmap->mddev->bitmap_info.daemon_sleep)))
return;
wait_event(bitmap->mddev->recovery_wait,
atomic_read(&bitmap->mddev->recovery_active) == 0);
bitmap->mddev->curr_resync_completed = sector;
set_bit(MD_SB_CHANGE_CLEAN, &bitmap->mddev->sb_flags);
sector &= ~((1ULL << bitmap->counts.chunkshift) - 1);
s = 0;
while (s < sector && s < bitmap->mddev->resync_max_sectors) {
md_bitmap_end_sync(bitmap, s, &blocks, 0);
s += blocks;
}
bitmap->last_end_sync = jiffies;
md: fix deadlock causing by sysfs_notify The following deadlock was captured. The first process is holding 'kernfs_mutex' and hung by io. The io was staging in 'r1conf.pending_bio_list' of raid1 device, this pending bio list would be flushed by second process 'md127_raid1', but it was hung by 'kernfs_mutex'. Using sysfs_notify_dirent_safe() to replace sysfs_notify() can fix it. There were other sysfs_notify() invoked from io path, removed all of them. PID: 40430 TASK: ffff8ee9c8c65c40 CPU: 29 COMMAND: "probe_file" #0 [ffffb87c4df37260] __schedule at ffffffff9a8678ec #1 [ffffb87c4df372f8] schedule at ffffffff9a867f06 #2 [ffffb87c4df37310] io_schedule at ffffffff9a0c73e6 #3 [ffffb87c4df37328] __dta___xfs_iunpin_wait_3443 at ffffffffc03a4057 [xfs] #4 [ffffb87c4df373a0] xfs_iunpin_wait at ffffffffc03a6c79 [xfs] #5 [ffffb87c4df373b0] __dta_xfs_reclaim_inode_3357 at ffffffffc039a46c [xfs] #6 [ffffb87c4df37400] xfs_reclaim_inodes_ag at ffffffffc039a8b6 [xfs] #7 [ffffb87c4df37590] xfs_reclaim_inodes_nr at ffffffffc039bb33 [xfs] #8 [ffffb87c4df375b0] xfs_fs_free_cached_objects at ffffffffc03af0e9 [xfs] #9 [ffffb87c4df375c0] super_cache_scan at ffffffff9a287ec7 #10 [ffffb87c4df37618] shrink_slab at ffffffff9a1efd93 #11 [ffffb87c4df37700] shrink_node at ffffffff9a1f5968 #12 [ffffb87c4df37788] do_try_to_free_pages at ffffffff9a1f5ea2 #13 [ffffb87c4df377f0] try_to_free_mem_cgroup_pages at ffffffff9a1f6445 #14 [ffffb87c4df37880] try_charge at ffffffff9a26cc5f #15 [ffffb87c4df37920] memcg_kmem_charge_memcg at ffffffff9a270f6a #16 [ffffb87c4df37958] new_slab at ffffffff9a251430 #17 [ffffb87c4df379c0] ___slab_alloc at ffffffff9a251c85 #18 [ffffb87c4df37a80] __slab_alloc at ffffffff9a25635d #19 [ffffb87c4df37ac0] kmem_cache_alloc at ffffffff9a251f89 #20 [ffffb87c4df37b00] alloc_inode at ffffffff9a2a2b10 #21 [ffffb87c4df37b20] iget_locked at ffffffff9a2a4854 #22 [ffffb87c4df37b60] kernfs_get_inode at ffffffff9a311377 #23 [ffffb87c4df37b80] kernfs_iop_lookup at ffffffff9a311e2b #24 [ffffb87c4df37ba8] lookup_slow at ffffffff9a290118 #25 [ffffb87c4df37c10] walk_component at ffffffff9a291e83 #26 [ffffb87c4df37c78] path_lookupat at ffffffff9a293619 #27 [ffffb87c4df37cd8] filename_lookup at ffffffff9a2953af #28 [ffffb87c4df37de8] user_path_at_empty at ffffffff9a295566 #29 [ffffb87c4df37e10] vfs_statx at ffffffff9a289787 #30 [ffffb87c4df37e70] SYSC_newlstat at ffffffff9a289d5d #31 [ffffb87c4df37f18] sys_newlstat at ffffffff9a28a60e #32 [ffffb87c4df37f28] do_syscall_64 at ffffffff9a003949 #33 [ffffb87c4df37f50] entry_SYSCALL_64_after_hwframe at ffffffff9aa001ad RIP: 00007f617a5f2905 RSP: 00007f607334f838 RFLAGS: 00000246 RAX: ffffffffffffffda RBX: 00007f6064044b20 RCX: 00007f617a5f2905 RDX: 00007f6064044b20 RSI: 00007f6064044b20 RDI: 00007f6064005890 RBP: 00007f6064044aa0 R8: 0000000000000030 R9: 000000000000011c R10: 0000000000000013 R11: 0000000000000246 R12: 00007f606417e6d0 R13: 00007f6064044aa0 R14: 00007f6064044b10 R15: 00000000ffffffff ORIG_RAX: 0000000000000006 CS: 0033 SS: 002b PID: 927 TASK: ffff8f15ac5dbd80 CPU: 42 COMMAND: "md127_raid1" #0 [ffffb87c4df07b28] __schedule at ffffffff9a8678ec #1 [ffffb87c4df07bc0] schedule at ffffffff9a867f06 #2 [ffffb87c4df07bd8] schedule_preempt_disabled at ffffffff9a86825e #3 [ffffb87c4df07be8] __mutex_lock at ffffffff9a869bcc #4 [ffffb87c4df07ca0] __mutex_lock_slowpath at ffffffff9a86a013 #5 [ffffb87c4df07cb0] mutex_lock at ffffffff9a86a04f #6 [ffffb87c4df07cc8] kernfs_find_and_get_ns at ffffffff9a311d83 #7 [ffffb87c4df07cf0] sysfs_notify at ffffffff9a314b3a #8 [ffffb87c4df07d18] md_update_sb at ffffffff9a688696 #9 [ffffb87c4df07d98] md_update_sb at ffffffff9a6886d5 #10 [ffffb87c4df07da8] md_check_recovery at ffffffff9a68ad9c #11 [ffffb87c4df07dd0] raid1d at ffffffffc01f0375 [raid1] #12 [ffffb87c4df07ea0] md_thread at ffffffff9a680348 #13 [ffffb87c4df07f08] kthread at ffffffff9a0b8005 #14 [ffffb87c4df07f50] ret_from_fork at ffffffff9aa00344 Signed-off-by: Junxiao Bi <junxiao.bi@oracle.com> Signed-off-by: Song Liu <songliubraving@fb.com>
2020-07-15 07:10:26 +08:00
sysfs_notify_dirent_safe(bitmap->mddev->sysfs_completed);
}
EXPORT_SYMBOL(md_bitmap_cond_end_sync);
void md_bitmap_sync_with_cluster(struct mddev *mddev,
sector_t old_lo, sector_t old_hi,
sector_t new_lo, sector_t new_hi)
{
struct bitmap *bitmap = mddev->bitmap;
sector_t sector, blocks = 0;
for (sector = old_lo; sector < new_lo; ) {
md_bitmap_end_sync(bitmap, sector, &blocks, 0);
sector += blocks;
}
WARN((blocks > new_lo) && old_lo, "alignment is not correct for lo\n");
for (sector = old_hi; sector < new_hi; ) {
md_bitmap_start_sync(bitmap, sector, &blocks, 0);
sector += blocks;
}
WARN((blocks > new_hi) && old_hi, "alignment is not correct for hi\n");
}
EXPORT_SYMBOL(md_bitmap_sync_with_cluster);
static void md_bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset, int needed)
{
/* For each chunk covered by any of these sectors, set the
* counter to 2 and possibly set resync_needed. They should all
* be 0 at this point
*/
sector_t secs;
bitmap_counter_t *bmc;
spin_lock_irq(&bitmap->counts.lock);
bmc = md_bitmap_get_counter(&bitmap->counts, offset, &secs, 1);
if (!bmc) {
spin_unlock_irq(&bitmap->counts.lock);
return;
}
if (!*bmc) {
*bmc = 2;
md_bitmap_count_page(&bitmap->counts, offset, 1);
md_bitmap_set_pending(&bitmap->counts, offset);
bitmap->allclean = 0;
}
if (needed)
*bmc |= NEEDED_MASK;
spin_unlock_irq(&bitmap->counts.lock);
}
/* dirty the memory and file bits for bitmap chunks "s" to "e" */
void md_bitmap_dirty_bits(struct bitmap *bitmap, unsigned long s, unsigned long e)
{
unsigned long chunk;
for (chunk = s; chunk <= e; chunk++) {
sector_t sec = (sector_t)chunk << bitmap->counts.chunkshift;
md_bitmap_set_memory_bits(bitmap, sec, 1);
md_bitmap_file_set_bit(bitmap, sec);
if (sec < bitmap->mddev->recovery_cp)
/* We are asserting that the array is dirty,
* so move the recovery_cp address back so
* that it is obvious that it is dirty
*/
bitmap->mddev->recovery_cp = sec;
}
}
/*
* flush out any pending updates
*/
void md_bitmap_flush(struct mddev *mddev)
{
struct bitmap *bitmap = mddev->bitmap;
long sleep;
if (!bitmap) /* there was no bitmap */
return;
/* run the daemon_work three time to ensure everything is flushed
* that can be
*/
sleep = mddev->bitmap_info.daemon_sleep * 2;
bitmap->daemon_lastrun -= sleep;
md_bitmap_daemon_work(mddev);
bitmap->daemon_lastrun -= sleep;
md_bitmap_daemon_work(mddev);
bitmap->daemon_lastrun -= sleep;
md_bitmap_daemon_work(mddev);
md/bitmap: wait for external bitmap writes to complete during tear down NULL pointer dereference was observed in super_written() when it tries to access the mddev structure. [The below stack trace is from an older kernel, but the problem described in this patch applies to the mainline kernel.] [ 1194.474861] task: ffff8fdd20858000 task.stack: ffffb99d40790000 [ 1194.488000] RIP: 0010:super_written+0x29/0xe1 [ 1194.499688] RSP: 0018:ffff8ffb7fcc3c78 EFLAGS: 00010046 [ 1194.512477] RAX: 0000000000000000 RBX: ffff8ffb7bf4a000 RCX: ffff8ffb78991048 [ 1194.527325] RDX: 0000000000000001 RSI: 0000000000000000 RDI: ffff8ffb56b8a200 [ 1194.542576] RBP: ffff8ffb7fcc3c90 R08: 000000000000000b R09: 0000000000000000 [ 1194.558001] R10: ffff8ffb56b8a298 R11: 0000000000000000 R12: ffff8ffb56b8a200 [ 1194.573070] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 [ 1194.588117] FS: 0000000000000000(0000) GS:ffff8ffb7fcc0000(0000) knlGS:0000000000000000 [ 1194.604264] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 1194.617375] CR2: 00000000000002b8 CR3: 00000021e040a002 CR4: 00000000007606e0 [ 1194.632327] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 1194.647865] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 1194.663316] PKRU: 55555554 [ 1194.674090] Call Trace: [ 1194.683735] <IRQ> [ 1194.692948] bio_endio+0xae/0x135 [ 1194.703580] blk_update_request+0xad/0x2fa [ 1194.714990] blk_update_bidi_request+0x20/0x72 [ 1194.726578] __blk_end_bidi_request+0x2c/0x4d [ 1194.738373] __blk_end_request_all+0x31/0x49 [ 1194.749344] blk_flush_complete_seq+0x377/0x383 [ 1194.761550] flush_end_io+0x1dd/0x2a7 [ 1194.772910] blk_finish_request+0x9f/0x13c [ 1194.784544] scsi_end_request+0x180/0x25c [ 1194.796149] scsi_io_completion+0xc8/0x610 [ 1194.807503] scsi_finish_command+0xdc/0x125 [ 1194.818897] scsi_softirq_done+0x81/0xde [ 1194.830062] blk_done_softirq+0xa4/0xcc [ 1194.841008] __do_softirq+0xd9/0x29f [ 1194.851257] irq_exit+0xe6/0xeb [ 1194.861290] do_IRQ+0x59/0xe3 [ 1194.871060] common_interrupt+0x1c6/0x382 [ 1194.881988] </IRQ> [ 1194.890646] RIP: 0010:cpuidle_enter_state+0xdd/0x2a5 [ 1194.902532] RSP: 0018:ffffb99d40793e68 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff43 [ 1194.917317] RAX: ffff8ffb7fce27c0 RBX: ffff8ffb7fced800 RCX: 000000000000001f [ 1194.932056] RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000000 [ 1194.946428] RBP: ffffb99d40793ea0 R08: 0000000000000004 R09: 0000000000002ed2 [ 1194.960508] R10: 0000000000002664 R11: 0000000000000018 R12: 0000000000000003 [ 1194.974454] R13: 000000000000000b R14: ffffffff925715a0 R15: 0000011610120d5a [ 1194.988607] ? cpuidle_enter_state+0xcc/0x2a5 [ 1194.999077] cpuidle_enter+0x17/0x19 [ 1195.008395] call_cpuidle+0x23/0x3a [ 1195.017718] do_idle+0x172/0x1d5 [ 1195.026358] cpu_startup_entry+0x73/0x75 [ 1195.035769] start_secondary+0x1b9/0x20b [ 1195.044894] secondary_startup_64+0xa5/0xa5 [ 1195.084921] RIP: super_written+0x29/0xe1 RSP: ffff8ffb7fcc3c78 [ 1195.096354] CR2: 00000000000002b8 bio in the above stack is a bitmap write whose completion is invoked after the tear down sequence sets the mddev structure to NULL in rdev. During tear down, there is an attempt to flush the bitmap writes, but for external bitmaps, there is no explicit wait for all the bitmap writes to complete. For instance, md_bitmap_flush() is called to flush the bitmap writes, but the last call to md_bitmap_daemon_work() in md_bitmap_flush() could generate new bitmap writes for which there is no explicit wait to complete those writes. The call to md_bitmap_update_sb() will return simply for external bitmaps and the follow-up call to md_update_sb() is conditional and may not get called for external bitmaps. This results in a kernel panic when the completion routine, super_written() is called which tries to reference mddev in the rdev that has been set to NULL(in unbind_rdev_from_array() by tear down sequence). The solution is to call md_super_wait() for external bitmaps after the last call to md_bitmap_daemon_work() in md_bitmap_flush() to ensure there are no pending bitmap writes before proceeding with the tear down. Cc: stable@vger.kernel.org Signed-off-by: Sudhakar Panneerselvam <sudhakar.panneerselvam@oracle.com> Reviewed-by: Zhao Heming <heming.zhao@suse.com> Signed-off-by: Song Liu <song@kernel.org>
2021-04-13 12:08:29 +08:00
if (mddev->bitmap_info.external)
md_super_wait(mddev);
md_bitmap_update_sb(bitmap);
}
/*
* free memory that was allocated
*/
void md_bitmap_free(struct bitmap *bitmap)
{
unsigned long k, pages;
struct bitmap_page *bp;
if (!bitmap) /* there was no bitmap */
return;
if (bitmap->sysfs_can_clear)
sysfs_put(bitmap->sysfs_can_clear);
if (mddev_is_clustered(bitmap->mddev) && bitmap->mddev->cluster_info &&
bitmap->cluster_slot == md_cluster_ops->slot_number(bitmap->mddev))
md_cluster_stop(bitmap->mddev);
/* Shouldn't be needed - but just in case.... */
wait_event(bitmap->write_wait,
atomic_read(&bitmap->pending_writes) == 0);
/* release the bitmap file */
md_bitmap_file_unmap(&bitmap->storage);
bp = bitmap->counts.bp;
pages = bitmap->counts.pages;
/* free all allocated memory */
if (bp) /* deallocate the page memory */
for (k = 0; k < pages; k++)
if (bp[k].map && !bp[k].hijacked)
kfree(bp[k].map);
kfree(bp);
kfree(bitmap);
}
EXPORT_SYMBOL(md_bitmap_free);
void md_bitmap_wait_behind_writes(struct mddev *mddev)
{
struct bitmap *bitmap = mddev->bitmap;
/* wait for behind writes to complete */
if (bitmap && atomic_read(&bitmap->behind_writes) > 0) {
pr_debug("md:%s: behind writes in progress - waiting to stop.\n",
mdname(mddev));
/* need to kick something here to make sure I/O goes? */
wait_event(bitmap->behind_wait,
atomic_read(&bitmap->behind_writes) == 0);
}
}
void md_bitmap_destroy(struct mddev *mddev)
{
struct bitmap *bitmap = mddev->bitmap;
if (!bitmap) /* there was no bitmap */
return;
md_bitmap_wait_behind_writes(mddev);
if (!mddev->serialize_policy)
mddev_destroy_serial_pool(mddev, NULL, true);
mutex_lock(&mddev->bitmap_info.mutex);
spin_lock(&mddev->lock);
mddev->bitmap = NULL; /* disconnect from the md device */
spin_unlock(&mddev->lock);
mutex_unlock(&mddev->bitmap_info.mutex);
if (mddev->thread)
mddev->thread->timeout = MAX_SCHEDULE_TIMEOUT;
md_bitmap_free(bitmap);
}
/*
* initialize the bitmap structure
* if this returns an error, bitmap_destroy must be called to do clean up
* once mddev->bitmap is set
*/
struct bitmap *md_bitmap_create(struct mddev *mddev, int slot)
{
struct bitmap *bitmap;
sector_t blocks = mddev->resync_max_sectors;
struct file *file = mddev->bitmap_info.file;
int err;
struct kernfs_node *bm = NULL;
BUILD_BUG_ON(sizeof(bitmap_super_t) != 256);
BUG_ON(file && mddev->bitmap_info.offset);
if (test_bit(MD_HAS_JOURNAL, &mddev->flags)) {
pr_notice("md/raid:%s: array with journal cannot have bitmap\n",
mdname(mddev));
return ERR_PTR(-EBUSY);
}
bitmap = kzalloc(sizeof(*bitmap), GFP_KERNEL);
if (!bitmap)
return ERR_PTR(-ENOMEM);
spin_lock_init(&bitmap->counts.lock);
atomic_set(&bitmap->pending_writes, 0);
init_waitqueue_head(&bitmap->write_wait);
init_waitqueue_head(&bitmap->overflow_wait);
init_waitqueue_head(&bitmap->behind_wait);
bitmap->mddev = mddev;
bitmap->cluster_slot = slot;
if (mddev->kobj.sd)
bm = sysfs_get_dirent(mddev->kobj.sd, "bitmap");
if (bm) {
bitmap->sysfs_can_clear = sysfs_get_dirent(bm, "can_clear");
sysfs_put(bm);
} else
bitmap->sysfs_can_clear = NULL;
bitmap->storage.file = file;
if (file) {
get_file(file);
/* As future accesses to this file will use bmap,
* and bypass the page cache, we must sync the file
* first.
*/
vfs_fsync(file, 1);
}
/* read superblock from bitmap file (this sets mddev->bitmap_info.chunksize) */
if (!mddev->bitmap_info.external) {
/*
* If 'MD_ARRAY_FIRST_USE' is set, then device-mapper is
* instructing us to create a new on-disk bitmap instance.
*/
if (test_and_clear_bit(MD_ARRAY_FIRST_USE, &mddev->flags))
err = md_bitmap_new_disk_sb(bitmap);
else
err = md_bitmap_read_sb(bitmap);
} else {
err = 0;
if (mddev->bitmap_info.chunksize == 0 ||
mddev->bitmap_info.daemon_sleep == 0)
/* chunksize and time_base need to be
* set first. */
err = -EINVAL;
}
if (err)
goto error;
bitmap->daemon_lastrun = jiffies;
err = md_bitmap_resize(bitmap, blocks, mddev->bitmap_info.chunksize, 1);
if (err)
goto error;
pr_debug("created bitmap (%lu pages) for device %s\n",
bitmap->counts.pages, bmname(bitmap));
err = test_bit(BITMAP_WRITE_ERROR, &bitmap->flags) ? -EIO : 0;
if (err)
goto error;
return bitmap;
error:
md_bitmap_free(bitmap);
return ERR_PTR(err);
}
int md_bitmap_load(struct mddev *mddev)
{
int err = 0;
sector_t start = 0;
sector_t sector = 0;
struct bitmap *bitmap = mddev->bitmap;
struct md_rdev *rdev;
if (!bitmap)
goto out;
rdev_for_each(rdev, mddev)
mddev_create_serial_pool(mddev, rdev, true);
if (mddev_is_clustered(mddev))
md_cluster_ops->load_bitmaps(mddev, mddev->bitmap_info.nodes);
/* Clear out old bitmap info first: Either there is none, or we
* are resuming after someone else has possibly changed things,
* so we should forget old cached info.
* All chunks should be clean, but some might need_sync.
*/
while (sector < mddev->resync_max_sectors) {
sector_t blocks;
md_bitmap_start_sync(bitmap, sector, &blocks, 0);
sector += blocks;
}
md_bitmap_close_sync(bitmap);
if (mddev->degraded == 0
|| bitmap->events_cleared == mddev->events)
/* no need to keep dirty bits to optimise a
* re-add of a missing device */
start = mddev->recovery_cp;
mutex_lock(&mddev->bitmap_info.mutex);
err = md_bitmap_init_from_disk(bitmap, start);
mutex_unlock(&mddev->bitmap_info.mutex);
if (err)
goto out;
clear_bit(BITMAP_STALE, &bitmap->flags);
/* Kick recovery in case any bits were set */
set_bit(MD_RECOVERY_NEEDED, &bitmap->mddev->recovery);
mddev->thread->timeout = mddev->bitmap_info.daemon_sleep;
md_wakeup_thread(mddev->thread);
md_bitmap_update_sb(bitmap);
if (test_bit(BITMAP_WRITE_ERROR, &bitmap->flags))
err = -EIO;
out:
return err;
}
EXPORT_SYMBOL_GPL(md_bitmap_load);
/* caller need to free returned bitmap with md_bitmap_free() */
struct bitmap *get_bitmap_from_slot(struct mddev *mddev, int slot)
{
int rv = 0;
struct bitmap *bitmap;
bitmap = md_bitmap_create(mddev, slot);
if (IS_ERR(bitmap)) {
rv = PTR_ERR(bitmap);
return ERR_PTR(rv);
}
rv = md_bitmap_init_from_disk(bitmap, 0);
if (rv) {
md_bitmap_free(bitmap);
return ERR_PTR(rv);
}
return bitmap;
}
EXPORT_SYMBOL(get_bitmap_from_slot);
/* Loads the bitmap associated with slot and copies the resync information
* to our bitmap
*/
int md_bitmap_copy_from_slot(struct mddev *mddev, int slot,
sector_t *low, sector_t *high, bool clear_bits)
{
int rv = 0, i, j;
sector_t block, lo = 0, hi = 0;
struct bitmap_counts *counts;
struct bitmap *bitmap;
bitmap = get_bitmap_from_slot(mddev, slot);
if (IS_ERR(bitmap)) {
pr_err("%s can't get bitmap from slot %d\n", __func__, slot);
return -1;
}
counts = &bitmap->counts;
for (j = 0; j < counts->chunks; j++) {
block = (sector_t)j << counts->chunkshift;
if (md_bitmap_file_test_bit(bitmap, block)) {
if (!lo)
lo = block;
hi = block;
md_bitmap_file_clear_bit(bitmap, block);
md_bitmap_set_memory_bits(mddev->bitmap, block, 1);
md_bitmap_file_set_bit(mddev->bitmap, block);
}
}
if (clear_bits) {
md_bitmap_update_sb(bitmap);
/* BITMAP_PAGE_PENDING is set, but bitmap_unplug needs
* BITMAP_PAGE_DIRTY or _NEEDWRITE to write ... */
for (i = 0; i < bitmap->storage.file_pages; i++)
if (test_page_attr(bitmap, i, BITMAP_PAGE_PENDING))
set_page_attr(bitmap, i, BITMAP_PAGE_NEEDWRITE);
md_bitmap_unplug(bitmap);
}
md_bitmap_unplug(mddev->bitmap);
*low = lo;
*high = hi;
md_bitmap_free(bitmap);
return rv;
}
EXPORT_SYMBOL_GPL(md_bitmap_copy_from_slot);
void md_bitmap_status(struct seq_file *seq, struct bitmap *bitmap)
{
unsigned long chunk_kb;
struct bitmap_counts *counts;
if (!bitmap)
return;
counts = &bitmap->counts;
chunk_kb = bitmap->mddev->bitmap_info.chunksize >> 10;
seq_printf(seq, "bitmap: %lu/%lu pages [%luKB], "
"%lu%s chunk",
counts->pages - counts->missing_pages,
counts->pages,
(counts->pages - counts->missing_pages)
<< (PAGE_SHIFT - 10),
chunk_kb ? chunk_kb : bitmap->mddev->bitmap_info.chunksize,
chunk_kb ? "KB" : "B");
if (bitmap->storage.file) {
seq_printf(seq, ", file: ");
seq_file_path(seq, bitmap->storage.file, " \t\n");
}
seq_printf(seq, "\n");
}
int md_bitmap_resize(struct bitmap *bitmap, sector_t blocks,
int chunksize, int init)
{
/* If chunk_size is 0, choose an appropriate chunk size.
* Then possibly allocate new storage space.
* Then quiesce, copy bits, replace bitmap, and re-start
*
* This function is called both to set up the initial bitmap
* and to resize the bitmap while the array is active.
* If this happens as a result of the array being resized,
* chunksize will be zero, and we need to choose a suitable
* chunksize, otherwise we use what we are given.
*/
struct bitmap_storage store;
struct bitmap_counts old_counts;
unsigned long chunks;
sector_t block;
sector_t old_blocks, new_blocks;
int chunkshift;
int ret = 0;
long pages;
struct bitmap_page *new_bp;
if (bitmap->storage.file && !init) {
pr_info("md: cannot resize file-based bitmap\n");
return -EINVAL;
}
if (chunksize == 0) {
/* If there is enough space, leave the chunk size unchanged,
* else increase by factor of two until there is enough space.
*/
long bytes;
long space = bitmap->mddev->bitmap_info.space;
if (space == 0) {
/* We don't know how much space there is, so limit
* to current size - in sectors.
*/
bytes = DIV_ROUND_UP(bitmap->counts.chunks, 8);
if (!bitmap->mddev->bitmap_info.external)
bytes += sizeof(bitmap_super_t);
space = DIV_ROUND_UP(bytes, 512);
bitmap->mddev->bitmap_info.space = space;
}
chunkshift = bitmap->counts.chunkshift;
chunkshift--;
do {
/* 'chunkshift' is shift from block size to chunk size */
chunkshift++;
chunks = DIV_ROUND_UP_SECTOR_T(blocks, 1 << chunkshift);
bytes = DIV_ROUND_UP(chunks, 8);
if (!bitmap->mddev->bitmap_info.external)
bytes += sizeof(bitmap_super_t);
} while (bytes > (space << 9));
} else
chunkshift = ffz(~chunksize) - BITMAP_BLOCK_SHIFT;
chunks = DIV_ROUND_UP_SECTOR_T(blocks, 1 << chunkshift);
memset(&store, 0, sizeof(store));
if (bitmap->mddev->bitmap_info.offset || bitmap->mddev->bitmap_info.file)
ret = md_bitmap_storage_alloc(&store, chunks,
!bitmap->mddev->bitmap_info.external,
mddev_is_clustered(bitmap->mddev)
? bitmap->cluster_slot : 0);
if (ret) {
md_bitmap_file_unmap(&store);
goto err;
}
pages = DIV_ROUND_UP(chunks, PAGE_COUNTER_RATIO);
treewide: kzalloc() -> kcalloc() The kzalloc() function has a 2-factor argument form, kcalloc(). This patch replaces cases of: kzalloc(a * b, gfp) with: kcalloc(a * b, gfp) as well as handling cases of: kzalloc(a * b * c, gfp) with: kzalloc(array3_size(a, b, c), gfp) as it's slightly less ugly than: kzalloc_array(array_size(a, b), c, gfp) This does, however, attempt to ignore constant size factors like: kzalloc(4 * 1024, gfp) though any constants defined via macros get caught up in the conversion. Any factors with a sizeof() of "unsigned char", "char", and "u8" were dropped, since they're redundant. The Coccinelle script used for this was: // Fix redundant parens around sizeof(). @@ type TYPE; expression THING, E; @@ ( kzalloc( - (sizeof(TYPE)) * E + sizeof(TYPE) * E , ...) | kzalloc( - (sizeof(THING)) * E + sizeof(THING) * E , ...) ) // Drop single-byte sizes and redundant parens. @@ expression COUNT; typedef u8; typedef __u8; @@ ( kzalloc( - sizeof(u8) * (COUNT) + COUNT , ...) | kzalloc( - sizeof(__u8) * (COUNT) + COUNT , ...) | kzalloc( - sizeof(char) * (COUNT) + COUNT , ...) | kzalloc( - sizeof(unsigned char) * (COUNT) + COUNT , ...) | kzalloc( - sizeof(u8) * COUNT + COUNT , ...) | kzalloc( - sizeof(__u8) * COUNT + COUNT , ...) | kzalloc( - sizeof(char) * COUNT + COUNT , ...) | kzalloc( - sizeof(unsigned char) * COUNT + COUNT , ...) ) // 2-factor product with sizeof(type/expression) and identifier or constant. @@ type TYPE; expression THING; identifier COUNT_ID; constant COUNT_CONST; @@ ( - kzalloc + kcalloc ( - sizeof(TYPE) * (COUNT_ID) + COUNT_ID, sizeof(TYPE) , ...) | - kzalloc + kcalloc ( - sizeof(TYPE) * COUNT_ID + COUNT_ID, sizeof(TYPE) , ...) | - kzalloc + kcalloc ( - sizeof(TYPE) * (COUNT_CONST) + COUNT_CONST, sizeof(TYPE) , ...) | - kzalloc + kcalloc ( - sizeof(TYPE) * COUNT_CONST + COUNT_CONST, sizeof(TYPE) , ...) | - kzalloc + kcalloc ( - sizeof(THING) * (COUNT_ID) + COUNT_ID, sizeof(THING) , ...) | - kzalloc + kcalloc ( - sizeof(THING) * COUNT_ID + COUNT_ID, sizeof(THING) , ...) | - kzalloc + kcalloc ( - sizeof(THING) * (COUNT_CONST) + COUNT_CONST, sizeof(THING) , ...) | - kzalloc + kcalloc ( - sizeof(THING) * COUNT_CONST + COUNT_CONST, sizeof(THING) , ...) ) // 2-factor product, only identifiers. @@ identifier SIZE, COUNT; @@ - kzalloc + kcalloc ( - SIZE * COUNT + COUNT, SIZE , ...) // 3-factor product with 1 sizeof(type) or sizeof(expression), with // redundant parens removed. @@ expression THING; identifier STRIDE, COUNT; type TYPE; @@ ( kzalloc( - sizeof(TYPE) * (COUNT) * (STRIDE) + array3_size(COUNT, STRIDE, sizeof(TYPE)) , ...) | kzalloc( - sizeof(TYPE) * (COUNT) * STRIDE + array3_size(COUNT, STRIDE, sizeof(TYPE)) , ...) | kzalloc( - sizeof(TYPE) * COUNT * (STRIDE) + array3_size(COUNT, STRIDE, sizeof(TYPE)) , ...) | kzalloc( - sizeof(TYPE) * COUNT * STRIDE + array3_size(COUNT, STRIDE, sizeof(TYPE)) , ...) | kzalloc( - sizeof(THING) * (COUNT) * (STRIDE) + array3_size(COUNT, STRIDE, sizeof(THING)) , ...) | kzalloc( - sizeof(THING) * (COUNT) * STRIDE + array3_size(COUNT, STRIDE, sizeof(THING)) , ...) | kzalloc( - sizeof(THING) * COUNT * (STRIDE) + array3_size(COUNT, STRIDE, sizeof(THING)) , ...) | kzalloc( - sizeof(THING) * COUNT * STRIDE + array3_size(COUNT, STRIDE, sizeof(THING)) , ...) ) // 3-factor product with 2 sizeof(variable), with redundant parens removed. @@ expression THING1, THING2; identifier COUNT; type TYPE1, TYPE2; @@ ( kzalloc( - sizeof(TYPE1) * sizeof(TYPE2) * COUNT + array3_size(COUNT, sizeof(TYPE1), sizeof(TYPE2)) , ...) | kzalloc( - sizeof(TYPE1) * sizeof(THING2) * (COUNT) + array3_size(COUNT, sizeof(TYPE1), sizeof(TYPE2)) , ...) | kzalloc( - sizeof(THING1) * sizeof(THING2) * COUNT + array3_size(COUNT, sizeof(THING1), sizeof(THING2)) , ...) | kzalloc( - sizeof(THING1) * sizeof(THING2) * (COUNT) + array3_size(COUNT, sizeof(THING1), sizeof(THING2)) , ...) | kzalloc( - sizeof(TYPE1) * sizeof(THING2) * COUNT + array3_size(COUNT, sizeof(TYPE1), sizeof(THING2)) , ...) | kzalloc( - sizeof(TYPE1) * sizeof(THING2) * (COUNT) + array3_size(COUNT, sizeof(TYPE1), sizeof(THING2)) , ...) ) // 3-factor product, only identifiers, with redundant parens removed. @@ identifier STRIDE, SIZE, COUNT; @@ ( kzalloc( - (COUNT) * STRIDE * SIZE + array3_size(COUNT, STRIDE, SIZE) , ...) | kzalloc( - COUNT * (STRIDE) * SIZE + array3_size(COUNT, STRIDE, SIZE) , ...) | kzalloc( - COUNT * STRIDE * (SIZE) + array3_size(COUNT, STRIDE, SIZE) , ...) | kzalloc( - (COUNT) * (STRIDE) * SIZE + array3_size(COUNT, STRIDE, SIZE) , ...) | kzalloc( - COUNT * (STRIDE) * (SIZE) + array3_size(COUNT, STRIDE, SIZE) , ...) | kzalloc( - (COUNT) * STRIDE * (SIZE) + array3_size(COUNT, STRIDE, SIZE) , ...) | kzalloc( - (COUNT) * (STRIDE) * (SIZE) + array3_size(COUNT, STRIDE, SIZE) , ...) | kzalloc( - COUNT * STRIDE * SIZE + array3_size(COUNT, STRIDE, SIZE) , ...) ) // Any remaining multi-factor products, first at least 3-factor products, // when they're not all constants... @@ expression E1, E2, E3; constant C1, C2, C3; @@ ( kzalloc(C1 * C2 * C3, ...) | kzalloc( - (E1) * E2 * E3 + array3_size(E1, E2, E3) , ...) | kzalloc( - (E1) * (E2) * E3 + array3_size(E1, E2, E3) , ...) | kzalloc( - (E1) * (E2) * (E3) + array3_size(E1, E2, E3) , ...) | kzalloc( - E1 * E2 * E3 + array3_size(E1, E2, E3) , ...) ) // And then all remaining 2 factors products when they're not all constants, // keeping sizeof() as the second factor argument. @@ expression THING, E1, E2; type TYPE; constant C1, C2, C3; @@ ( kzalloc(sizeof(THING) * C2, ...) | kzalloc(sizeof(TYPE) * C2, ...) | kzalloc(C1 * C2 * C3, ...) | kzalloc(C1 * C2, ...) | - kzalloc + kcalloc ( - sizeof(TYPE) * (E2) + E2, sizeof(TYPE) , ...) | - kzalloc + kcalloc ( - sizeof(TYPE) * E2 + E2, sizeof(TYPE) , ...) | - kzalloc + kcalloc ( - sizeof(THING) * (E2) + E2, sizeof(THING) , ...) | - kzalloc + kcalloc ( - sizeof(THING) * E2 + E2, sizeof(THING) , ...) | - kzalloc + kcalloc ( - (E1) * E2 + E1, E2 , ...) | - kzalloc + kcalloc ( - (E1) * (E2) + E1, E2 , ...) | - kzalloc + kcalloc ( - E1 * E2 + E1, E2 , ...) ) Signed-off-by: Kees Cook <keescook@chromium.org>
2018-06-13 05:03:40 +08:00
new_bp = kcalloc(pages, sizeof(*new_bp), GFP_KERNEL);
ret = -ENOMEM;
if (!new_bp) {
md_bitmap_file_unmap(&store);
goto err;
}
if (!init)
bitmap->mddev->pers->quiesce(bitmap->mddev, 1);
store.file = bitmap->storage.file;
bitmap->storage.file = NULL;
if (store.sb_page && bitmap->storage.sb_page)
memcpy(page_address(store.sb_page),
page_address(bitmap->storage.sb_page),
sizeof(bitmap_super_t));
md/bitmap: avoid race window between md_bitmap_resize and bitmap_file_clear_bit We need to move "spin_lock_irq(&bitmap->counts.lock)" before unmap previous storage, otherwise panic like belows could happen as follows. [ 902.353802] sdl: detected capacity change from 1077936128 to 3221225472 [ 902.616948] general protection fault: 0000 [#1] SMP [snip] [ 902.618588] CPU: 12 PID: 33698 Comm: md0_raid1 Tainted: G O 4.14.144-1-pserver #4.14.144-1.1~deb10 [ 902.618870] Hardware name: Supermicro SBA-7142G-T4/BHQGE, BIOS 3.00 10/24/2012 [ 902.619120] task: ffff9ae1860fc600 task.stack: ffffb52e4c704000 [ 902.619301] RIP: 0010:bitmap_file_clear_bit+0x90/0xd0 [md_mod] [ 902.619464] RSP: 0018:ffffb52e4c707d28 EFLAGS: 00010087 [ 902.619626] RAX: ffe8008b0d061000 RBX: ffff9ad078c87300 RCX: 0000000000000000 [ 902.619792] RDX: ffff9ad986341868 RSI: 0000000000000803 RDI: ffff9ad078c87300 [ 902.619986] RBP: ffff9ad0ed7a8000 R08: 0000000000000000 R09: 0000000000000000 [ 902.620154] R10: ffffb52e4c707ec0 R11: ffff9ad987d1ed44 R12: ffff9ad0ed7a8360 [ 902.620320] R13: 0000000000000003 R14: 0000000000060000 R15: 0000000000000800 [ 902.620487] FS: 0000000000000000(0000) GS:ffff9ad987d00000(0000) knlGS:0000000000000000 [ 902.620738] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 902.620901] CR2: 000055ff12aecec0 CR3: 0000001005207000 CR4: 00000000000406e0 [ 902.621068] Call Trace: [ 902.621256] bitmap_daemon_work+0x2dd/0x360 [md_mod] [ 902.621429] ? find_pers+0x70/0x70 [md_mod] [ 902.621597] md_check_recovery+0x51/0x540 [md_mod] [ 902.621762] raid1d+0x5c/0xeb0 [raid1] [ 902.621939] ? try_to_del_timer_sync+0x4d/0x80 [ 902.622102] ? del_timer_sync+0x35/0x40 [ 902.622265] ? schedule_timeout+0x177/0x360 [ 902.622453] ? call_timer_fn+0x130/0x130 [ 902.622623] ? find_pers+0x70/0x70 [md_mod] [ 902.622794] ? md_thread+0x94/0x150 [md_mod] [ 902.622959] md_thread+0x94/0x150 [md_mod] [ 902.623121] ? wait_woken+0x80/0x80 [ 902.623280] kthread+0x119/0x130 [ 902.623437] ? kthread_create_on_node+0x60/0x60 [ 902.623600] ret_from_fork+0x22/0x40 [ 902.624225] RIP: bitmap_file_clear_bit+0x90/0xd0 [md_mod] RSP: ffffb52e4c707d28 Because mdadm was running on another cpu to do resize, so bitmap_resize was called to replace bitmap as below shows. PID: 38801 TASK: ffff9ad074a90e00 CPU: 0 COMMAND: "mdadm" [exception RIP: queued_spin_lock_slowpath+56] [snip] -- <NMI exception stack> -- #5 [ffffb52e60f17c58] queued_spin_lock_slowpath at ffffffff9c0b27b8 #6 [ffffb52e60f17c58] bitmap_resize at ffffffffc0399877 [md_mod] #7 [ffffb52e60f17d30] raid1_resize at ffffffffc0285bf9 [raid1] #8 [ffffb52e60f17d50] update_size at ffffffffc038a31a [md_mod] #9 [ffffb52e60f17d70] md_ioctl at ffffffffc0395ca4 [md_mod] And the procedure to keep resize bitmap safe is allocate new storage space, then quiesce, copy bits, replace bitmap, and re-start. However the daemon (bitmap_daemon_work) could happen even the array is quiesced, which means when bitmap_file_clear_bit is triggered by raid1d, then it thinks it should be fine to access store->filemap since counts->lock is held, but resize could change the storage without the protection of the lock. Cc: Jack Wang <jinpu.wang@cloud.ionos.com> Cc: NeilBrown <neilb@suse.com> Signed-off-by: Guoqing Jiang <guoqing.jiang@cloud.ionos.com> Signed-off-by: Song Liu <songliubraving@fb.com>
2019-09-26 19:53:50 +08:00
spin_lock_irq(&bitmap->counts.lock);
md_bitmap_file_unmap(&bitmap->storage);
bitmap->storage = store;
old_counts = bitmap->counts;
bitmap->counts.bp = new_bp;
bitmap->counts.pages = pages;
bitmap->counts.missing_pages = pages;
bitmap->counts.chunkshift = chunkshift;
bitmap->counts.chunks = chunks;
bitmap->mddev->bitmap_info.chunksize = 1 << (chunkshift +
BITMAP_BLOCK_SHIFT);
blocks = min(old_counts.chunks << old_counts.chunkshift,
chunks << chunkshift);
/* For cluster raid, need to pre-allocate bitmap */
if (mddev_is_clustered(bitmap->mddev)) {
unsigned long page;
for (page = 0; page < pages; page++) {
ret = md_bitmap_checkpage(&bitmap->counts, page, 1, 1);
if (ret) {
unsigned long k;
/* deallocate the page memory */
for (k = 0; k < page; k++) {
kfree(new_bp[k].map);
}
kfree(new_bp);
/* restore some fields from old_counts */
bitmap->counts.bp = old_counts.bp;
bitmap->counts.pages = old_counts.pages;
bitmap->counts.missing_pages = old_counts.pages;
bitmap->counts.chunkshift = old_counts.chunkshift;
bitmap->counts.chunks = old_counts.chunks;
bitmap->mddev->bitmap_info.chunksize = 1 << (old_counts.chunkshift +
BITMAP_BLOCK_SHIFT);
blocks = old_counts.chunks << old_counts.chunkshift;
pr_warn("Could not pre-allocate in-memory bitmap for cluster raid\n");
break;
} else
bitmap->counts.bp[page].count += 1;
}
}
for (block = 0; block < blocks; ) {
bitmap_counter_t *bmc_old, *bmc_new;
int set;
bmc_old = md_bitmap_get_counter(&old_counts, block, &old_blocks, 0);
set = bmc_old && NEEDED(*bmc_old);
if (set) {
bmc_new = md_bitmap_get_counter(&bitmap->counts, block, &new_blocks, 1);
if (*bmc_new == 0) {
/* need to set on-disk bits too. */
sector_t end = block + new_blocks;
sector_t start = block >> chunkshift;
start <<= chunkshift;
while (start < end) {
md_bitmap_file_set_bit(bitmap, block);
start += 1 << chunkshift;
}
*bmc_new = 2;
md_bitmap_count_page(&bitmap->counts, block, 1);
md_bitmap_set_pending(&bitmap->counts, block);
}
*bmc_new |= NEEDED_MASK;
if (new_blocks < old_blocks)
old_blocks = new_blocks;
}
block += old_blocks;
}
if (bitmap->counts.bp != old_counts.bp) {
unsigned long k;
for (k = 0; k < old_counts.pages; k++)
if (!old_counts.bp[k].hijacked)
kfree(old_counts.bp[k].map);
kfree(old_counts.bp);
}
if (!init) {
int i;
while (block < (chunks << chunkshift)) {
bitmap_counter_t *bmc;
bmc = md_bitmap_get_counter(&bitmap->counts, block, &new_blocks, 1);
if (bmc) {
/* new space. It needs to be resynced, so
* we set NEEDED_MASK.
*/
if (*bmc == 0) {
*bmc = NEEDED_MASK | 2;
md_bitmap_count_page(&bitmap->counts, block, 1);
md_bitmap_set_pending(&bitmap->counts, block);
}
}
block += new_blocks;
}
for (i = 0; i < bitmap->storage.file_pages; i++)
set_page_attr(bitmap, i, BITMAP_PAGE_DIRTY);
}
spin_unlock_irq(&bitmap->counts.lock);
if (!init) {
md_bitmap_unplug(bitmap);
bitmap->mddev->pers->quiesce(bitmap->mddev, 0);
}
ret = 0;
err:
return ret;
}
EXPORT_SYMBOL_GPL(md_bitmap_resize);
static ssize_t
location_show(struct mddev *mddev, char *page)
{
ssize_t len;
if (mddev->bitmap_info.file)
len = sprintf(page, "file");
else if (mddev->bitmap_info.offset)
len = sprintf(page, "%+lld", (long long)mddev->bitmap_info.offset);
else
len = sprintf(page, "none");
len += sprintf(page+len, "\n");
return len;
}
static ssize_t
location_store(struct mddev *mddev, const char *buf, size_t len)
{
int rv;
rv = mddev_lock(mddev);
if (rv)
return rv;
if (mddev->pers) {
if (!mddev->pers->quiesce) {
rv = -EBUSY;
goto out;
}
if (mddev->recovery || mddev->sync_thread) {
rv = -EBUSY;
goto out;
}
}
if (mddev->bitmap || mddev->bitmap_info.file ||
mddev->bitmap_info.offset) {
/* bitmap already configured. Only option is to clear it */
if (strncmp(buf, "none", 4) != 0) {
rv = -EBUSY;
goto out;
}
if (mddev->pers) {
mddev_suspend(mddev);
md_bitmap_destroy(mddev);
mddev_resume(mddev);
}
mddev->bitmap_info.offset = 0;
if (mddev->bitmap_info.file) {
struct file *f = mddev->bitmap_info.file;
mddev->bitmap_info.file = NULL;
fput(f);
}
} else {
/* No bitmap, OK to set a location */
long long offset;
if (strncmp(buf, "none", 4) == 0)
/* nothing to be done */;
else if (strncmp(buf, "file:", 5) == 0) {
/* Not supported yet */
rv = -EINVAL;
goto out;
} else {
if (buf[0] == '+')
rv = kstrtoll(buf+1, 10, &offset);
else
rv = kstrtoll(buf, 10, &offset);
if (rv)
goto out;
if (offset == 0) {
rv = -EINVAL;
goto out;
}
if (mddev->bitmap_info.external == 0 &&
mddev->major_version == 0 &&
offset != mddev->bitmap_info.default_offset) {
rv = -EINVAL;
goto out;
}
mddev->bitmap_info.offset = offset;
if (mddev->pers) {
struct bitmap *bitmap;
bitmap = md_bitmap_create(mddev, -1);
mddev_suspend(mddev);
if (IS_ERR(bitmap))
rv = PTR_ERR(bitmap);
else {
mddev->bitmap = bitmap;
rv = md_bitmap_load(mddev);
if (rv)
mddev->bitmap_info.offset = 0;
}
if (rv) {
md_bitmap_destroy(mddev);
mddev_resume(mddev);
goto out;
}
mddev_resume(mddev);
}
}
}
if (!mddev->external) {
/* Ensure new bitmap info is stored in
* metadata promptly.
*/
set_bit(MD_SB_CHANGE_DEVS, &mddev->sb_flags);
md_wakeup_thread(mddev->thread);
}
rv = 0;
out:
mddev_unlock(mddev);
if (rv)
return rv;
return len;
}
static struct md_sysfs_entry bitmap_location =
__ATTR(location, S_IRUGO|S_IWUSR, location_show, location_store);
/* 'bitmap/space' is the space available at 'location' for the
* bitmap. This allows the kernel to know when it is safe to
* resize the bitmap to match a resized array.
*/
static ssize_t
space_show(struct mddev *mddev, char *page)
{
return sprintf(page, "%lu\n", mddev->bitmap_info.space);
}
static ssize_t
space_store(struct mddev *mddev, const char *buf, size_t len)
{
unsigned long sectors;
int rv;
rv = kstrtoul(buf, 10, &sectors);
if (rv)
return rv;
if (sectors == 0)
return -EINVAL;
if (mddev->bitmap &&
sectors < (mddev->bitmap->storage.bytes + 511) >> 9)
return -EFBIG; /* Bitmap is too big for this small space */
/* could make sure it isn't too big, but that isn't really
* needed - user-space should be careful.
*/
mddev->bitmap_info.space = sectors;
return len;
}
static struct md_sysfs_entry bitmap_space =
__ATTR(space, S_IRUGO|S_IWUSR, space_show, space_store);
static ssize_t
timeout_show(struct mddev *mddev, char *page)
{
ssize_t len;
unsigned long secs = mddev->bitmap_info.daemon_sleep / HZ;
unsigned long jifs = mddev->bitmap_info.daemon_sleep % HZ;
len = sprintf(page, "%lu", secs);
if (jifs)
len += sprintf(page+len, ".%03u", jiffies_to_msecs(jifs));
len += sprintf(page+len, "\n");
return len;
}
static ssize_t
timeout_store(struct mddev *mddev, const char *buf, size_t len)
{
/* timeout can be set at any time */
unsigned long timeout;
int rv = strict_strtoul_scaled(buf, &timeout, 4);
if (rv)
return rv;
/* just to make sure we don't overflow... */
if (timeout >= LONG_MAX / HZ)
return -EINVAL;
timeout = timeout * HZ / 10000;
if (timeout >= MAX_SCHEDULE_TIMEOUT)
timeout = MAX_SCHEDULE_TIMEOUT-1;
if (timeout < 1)
timeout = 1;
mddev->bitmap_info.daemon_sleep = timeout;
if (mddev->thread) {
/* if thread->timeout is MAX_SCHEDULE_TIMEOUT, then
* the bitmap is all clean and we don't need to
* adjust the timeout right now
*/
if (mddev->thread->timeout < MAX_SCHEDULE_TIMEOUT) {
mddev->thread->timeout = timeout;
md_wakeup_thread(mddev->thread);
}
}
return len;
}
static struct md_sysfs_entry bitmap_timeout =
__ATTR(time_base, S_IRUGO|S_IWUSR, timeout_show, timeout_store);
static ssize_t
backlog_show(struct mddev *mddev, char *page)
{
return sprintf(page, "%lu\n", mddev->bitmap_info.max_write_behind);
}
static ssize_t
backlog_store(struct mddev *mddev, const char *buf, size_t len)
{
unsigned long backlog;
unsigned long old_mwb = mddev->bitmap_info.max_write_behind;
int rv = kstrtoul(buf, 10, &backlog);
if (rv)
return rv;
if (backlog > COUNTER_MAX)
return -EINVAL;
mddev->bitmap_info.max_write_behind = backlog;
if (!backlog && mddev->serial_info_pool) {
/* serial_info_pool is not needed if backlog is zero */
if (!mddev->serialize_policy)
mddev_destroy_serial_pool(mddev, NULL, false);
} else if (backlog && !mddev->serial_info_pool) {
/* serial_info_pool is needed since backlog is not zero */
struct md_rdev *rdev;
rdev_for_each(rdev, mddev)
mddev_create_serial_pool(mddev, rdev, false);
}
if (old_mwb != backlog)
md_bitmap_update_sb(mddev->bitmap);
return len;
}
static struct md_sysfs_entry bitmap_backlog =
__ATTR(backlog, S_IRUGO|S_IWUSR, backlog_show, backlog_store);
static ssize_t
chunksize_show(struct mddev *mddev, char *page)
{
return sprintf(page, "%lu\n", mddev->bitmap_info.chunksize);
}
static ssize_t
chunksize_store(struct mddev *mddev, const char *buf, size_t len)
{
/* Can only be changed when no bitmap is active */
int rv;
unsigned long csize;
if (mddev->bitmap)
return -EBUSY;
rv = kstrtoul(buf, 10, &csize);
if (rv)
return rv;
if (csize < 512 ||
!is_power_of_2(csize))
return -EINVAL;
mddev->bitmap_info.chunksize = csize;
return len;
}
static struct md_sysfs_entry bitmap_chunksize =
__ATTR(chunksize, S_IRUGO|S_IWUSR, chunksize_show, chunksize_store);
static ssize_t metadata_show(struct mddev *mddev, char *page)
{
if (mddev_is_clustered(mddev))
return sprintf(page, "clustered\n");
return sprintf(page, "%s\n", (mddev->bitmap_info.external
? "external" : "internal"));
}
static ssize_t metadata_store(struct mddev *mddev, const char *buf, size_t len)
{
if (mddev->bitmap ||
mddev->bitmap_info.file ||
mddev->bitmap_info.offset)
return -EBUSY;
if (strncmp(buf, "external", 8) == 0)
mddev->bitmap_info.external = 1;
else if ((strncmp(buf, "internal", 8) == 0) ||
(strncmp(buf, "clustered", 9) == 0))
mddev->bitmap_info.external = 0;
else
return -EINVAL;
return len;
}
static struct md_sysfs_entry bitmap_metadata =
__ATTR(metadata, S_IRUGO|S_IWUSR, metadata_show, metadata_store);
static ssize_t can_clear_show(struct mddev *mddev, char *page)
{
int len;
spin_lock(&mddev->lock);
if (mddev->bitmap)
len = sprintf(page, "%s\n", (mddev->bitmap->need_sync ?
"false" : "true"));
else
len = sprintf(page, "\n");
spin_unlock(&mddev->lock);
return len;
}
static ssize_t can_clear_store(struct mddev *mddev, const char *buf, size_t len)
{
if (mddev->bitmap == NULL)
return -ENOENT;
if (strncmp(buf, "false", 5) == 0)
mddev->bitmap->need_sync = 1;
else if (strncmp(buf, "true", 4) == 0) {
if (mddev->degraded)
return -EBUSY;
mddev->bitmap->need_sync = 0;
} else
return -EINVAL;
return len;
}
static struct md_sysfs_entry bitmap_can_clear =
__ATTR(can_clear, S_IRUGO|S_IWUSR, can_clear_show, can_clear_store);
static ssize_t
behind_writes_used_show(struct mddev *mddev, char *page)
{
ssize_t ret;
spin_lock(&mddev->lock);
if (mddev->bitmap == NULL)
ret = sprintf(page, "0\n");
else
ret = sprintf(page, "%lu\n",
mddev->bitmap->behind_writes_used);
spin_unlock(&mddev->lock);
return ret;
}
static ssize_t
behind_writes_used_reset(struct mddev *mddev, const char *buf, size_t len)
{
if (mddev->bitmap)
mddev->bitmap->behind_writes_used = 0;
return len;
}
static struct md_sysfs_entry max_backlog_used =
__ATTR(max_backlog_used, S_IRUGO | S_IWUSR,
behind_writes_used_show, behind_writes_used_reset);
static struct attribute *md_bitmap_attrs[] = {
&bitmap_location.attr,
&bitmap_space.attr,
&bitmap_timeout.attr,
&bitmap_backlog.attr,
&bitmap_chunksize.attr,
&bitmap_metadata.attr,
&bitmap_can_clear.attr,
&max_backlog_used.attr,
NULL
};
struct attribute_group md_bitmap_group = {
.name = "bitmap",
.attrs = md_bitmap_attrs,
};