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Date: Thu, 14 Oct 2021 10:30:24 -0400
From: Kent Overstreet <kent.overstreet@...il.com>
To: "heming.zhao@...e.com" <heming.zhao@...e.com>
Cc: Guoqing Jiang <guoqing.jiang@...ux.dev>,
linux-kernel@...r.kernel.org, linux-mm@...ck.org,
akpm@...ux-foundation.org, linux-raid@...r.kernel.org,
linux-block@...r.kernel.org, axboe@...nel.dk,
alexander.h.duyck@...ux.intel.com
Subject: [PATCH v2] md: Kill usage of page->index
On Thu, Oct 14, 2021 at 04:58:46PM +0800, heming.zhao@...e.com wrote:
> Hello all,
>
> The page->index takes an important role for cluster-md module.
> i.e, a two-node HA env, node A bitmap may be managed in first 4K area, then
> node B bitmap is in 8K area (the second page). this patch removes the index
> and fix/hardcode index with value 0, which will only operate first node bitmap.
>
> If this serial patches are important and must be merged in mainline, we should
> redesign code logic for the related code.
>
> Thanks,
> Heming
Can you look at and test the updated patch below? The more I look at the md
bitmap code the more it scares me.
-- >8 --
Subject: [PATCH] md: Kill usage of page->index
As part of the struct page cleanups underway, we want to remove as much
usage of page->mapping and page->index as possible, as frequently they
are known from context - as they are here in the md bitmap code.
Signed-off-by: Kent Overstreet <kent.overstreet@...il.com>
---
drivers/md/md-bitmap.c | 49 ++++++++++++++++++++----------------------
drivers/md/md-bitmap.h | 1 +
2 files changed, 24 insertions(+), 26 deletions(-)
diff --git a/drivers/md/md-bitmap.c b/drivers/md/md-bitmap.c
index e29c6298ef..316e4cd5a7 100644
--- a/drivers/md/md-bitmap.c
+++ b/drivers/md/md-bitmap.c
@@ -165,10 +165,8 @@ static int read_sb_page(struct mddev *mddev, loff_t offset,
if (sync_page_io(rdev, target,
roundup(size, bdev_logical_block_size(rdev->bdev)),
- page, REQ_OP_READ, 0, true)) {
- page->index = index;
+ page, REQ_OP_READ, 0, true))
return 0;
- }
}
return -EIO;
}
@@ -209,7 +207,8 @@ static struct md_rdev *next_active_rdev(struct md_rdev *rdev, struct mddev *mdde
return NULL;
}
-static int write_sb_page(struct bitmap *bitmap, struct page *page, int wait)
+static int write_sb_page(struct bitmap *bitmap, struct page *page,
+ unsigned long index, int wait)
{
struct md_rdev *rdev;
struct block_device *bdev;
@@ -224,7 +223,7 @@ static int write_sb_page(struct bitmap *bitmap, struct page *page, int wait)
bdev = (rdev->meta_bdev) ? rdev->meta_bdev : rdev->bdev;
- if (page->index == store->file_pages-1) {
+ if (index == store->file_pages-1) {
int last_page_size = store->bytes & (PAGE_SIZE-1);
if (last_page_size == 0)
last_page_size = PAGE_SIZE;
@@ -236,8 +235,7 @@ static int write_sb_page(struct bitmap *bitmap, struct page *page, int wait)
*/
if (mddev->external) {
/* Bitmap could be anywhere. */
- if (rdev->sb_start + offset + (page->index
- * (PAGE_SIZE/512))
+ if (rdev->sb_start + offset + index * PAGE_SECTORS
> rdev->data_offset
&&
rdev->sb_start + offset
@@ -247,7 +245,7 @@ static int write_sb_page(struct bitmap *bitmap, struct page *page, int wait)
} else if (offset < 0) {
/* DATA BITMAP METADATA */
if (offset
- + (long)(page->index * (PAGE_SIZE/512))
+ + (long)(index * PAGE_SECTORS)
+ size/512 > 0)
/* bitmap runs in to metadata */
goto bad_alignment;
@@ -259,7 +257,7 @@ static int write_sb_page(struct bitmap *bitmap, struct page *page, int wait)
/* METADATA BITMAP DATA */
if (rdev->sb_start
+ offset
- + page->index*(PAGE_SIZE/512) + size/512
+ + index * PAGE_SECTORS + size/512
> rdev->data_offset)
/* bitmap runs in to data */
goto bad_alignment;
@@ -268,7 +266,7 @@ static int write_sb_page(struct bitmap *bitmap, struct page *page, int wait)
}
md_super_write(mddev, rdev,
rdev->sb_start + offset
- + page->index * (PAGE_SIZE/512),
+ + index * PAGE_SECTORS,
size,
page);
}
@@ -285,12 +283,13 @@ 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)
+static void write_page(struct bitmap *bitmap, struct page *page,
+ unsigned long index, int wait)
{
struct buffer_head *bh;
if (bitmap->storage.file == NULL) {
- switch (write_sb_page(bitmap, page, wait)) {
+ switch (write_sb_page(bitmap, page, index, wait)) {
case -EINVAL:
set_bit(BITMAP_WRITE_ERROR, &bitmap->flags);
}
@@ -399,7 +398,6 @@ static int read_page(struct file *file, unsigned long index,
blk_cur++;
bh = bh->b_this_page;
}
- page->index = index;
wait_event(bitmap->write_wait,
atomic_read(&bitmap->pending_writes)==0);
@@ -472,7 +470,7 @@ void md_bitmap_update_sb(struct bitmap *bitmap)
sb->sectors_reserved = cpu_to_le32(bitmap->mddev->
bitmap_info.space);
kunmap_atomic(sb);
- write_page(bitmap, bitmap->storage.sb_page, 1);
+ write_page(bitmap, bitmap->storage.sb_page, bitmap->storage.sb_index, 1);
}
EXPORT_SYMBOL(md_bitmap_update_sb);
@@ -524,7 +522,6 @@ static int md_bitmap_new_disk_sb(struct bitmap *bitmap)
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);
@@ -776,7 +773,7 @@ static int md_bitmap_storage_alloc(struct bitmap_storage *store,
unsigned long chunks, int with_super,
int slot_number)
{
- int pnum, offset = 0;
+ int pnum;
unsigned long num_pages;
unsigned long bytes;
@@ -785,7 +782,7 @@ static int md_bitmap_storage_alloc(struct bitmap_storage *store,
bytes += sizeof(bitmap_super_t);
num_pages = DIV_ROUND_UP(bytes, PAGE_SIZE);
- offset = slot_number * num_pages;
+ store->sb_index = slot_number * num_pages;
store->filemap = kmalloc_array(num_pages, sizeof(struct page *),
GFP_KERNEL);
@@ -802,7 +799,6 @@ static int md_bitmap_storage_alloc(struct bitmap_storage *store,
if (store->sb_page) {
store->filemap[0] = store->sb_page;
pnum = 1;
- store->sb_page->index = offset;
}
for ( ; pnum < num_pages; pnum++) {
@@ -811,7 +807,6 @@ static int md_bitmap_storage_alloc(struct bitmap_storage *store,
store->file_pages = pnum;
return -ENOMEM;
}
- store->filemap[pnum]->index = pnum + offset;
}
store->file_pages = pnum;
@@ -929,6 +924,7 @@ static void md_bitmap_file_set_bit(struct bitmap *bitmap, sector_t block)
unsigned long chunk = block >> bitmap->counts.chunkshift;
struct bitmap_storage *store = &bitmap->storage;
unsigned long node_offset = 0;
+ unsigned long index = file_page_index(store, chunk);
if (mddev_is_clustered(bitmap->mddev))
node_offset = bitmap->cluster_slot * store->file_pages;
@@ -945,9 +941,9 @@ static void md_bitmap_file_set_bit(struct bitmap *bitmap, sector_t block)
else
set_bit_le(bit, kaddr);
kunmap_atomic(kaddr);
- pr_debug("set file bit %lu page %lu\n", bit, page->index);
+ pr_debug("set file bit %lu page %lu\n", bit, index);
/* record page number so it gets flushed to disk when unplug occurs */
- set_page_attr(bitmap, page->index - node_offset, BITMAP_PAGE_DIRTY);
+ set_page_attr(bitmap, index - node_offset, BITMAP_PAGE_DIRTY);
}
static void md_bitmap_file_clear_bit(struct bitmap *bitmap, sector_t block)
@@ -958,6 +954,7 @@ static void md_bitmap_file_clear_bit(struct bitmap *bitmap, sector_t block)
unsigned long chunk = block >> bitmap->counts.chunkshift;
struct bitmap_storage *store = &bitmap->storage;
unsigned long node_offset = 0;
+ unsigned long index = file_page_index(store, chunk);
if (mddev_is_clustered(bitmap->mddev))
node_offset = bitmap->cluster_slot * store->file_pages;
@@ -972,8 +969,8 @@ static void md_bitmap_file_clear_bit(struct bitmap *bitmap, sector_t block)
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);
+ if (!test_page_attr(bitmap, index - node_offset, BITMAP_PAGE_NEEDWRITE)) {
+ set_page_attr(bitmap, index - node_offset, BITMAP_PAGE_PENDING);
bitmap->allclean = 0;
}
}
@@ -1027,7 +1024,7 @@ void md_bitmap_unplug(struct bitmap *bitmap)
"md bitmap_unplug");
}
clear_page_attr(bitmap, i, BITMAP_PAGE_PENDING);
- write_page(bitmap, bitmap->storage.filemap[i], 0);
+ write_page(bitmap, bitmap->storage.filemap[i], i, 0);
writing = 1;
}
}
@@ -1137,7 +1134,7 @@ static int md_bitmap_init_from_disk(struct bitmap *bitmap, sector_t start)
memset(paddr + offset, 0xff,
PAGE_SIZE - offset);
kunmap_atomic(paddr);
- write_page(bitmap, page, 1);
+ write_page(bitmap, page, index, 1);
ret = -EIO;
if (test_bit(BITMAP_WRITE_ERROR,
@@ -1336,7 +1333,7 @@ void md_bitmap_daemon_work(struct mddev *mddev)
if (bitmap->storage.filemap &&
test_and_clear_page_attr(bitmap, j,
BITMAP_PAGE_NEEDWRITE)) {
- write_page(bitmap, bitmap->storage.filemap[j], 0);
+ write_page(bitmap, bitmap->storage.filemap[j], j, 0);
}
}
diff --git a/drivers/md/md-bitmap.h b/drivers/md/md-bitmap.h
index cfd7395de8..6e820eea32 100644
--- a/drivers/md/md-bitmap.h
+++ b/drivers/md/md-bitmap.h
@@ -207,6 +207,7 @@ struct bitmap {
* w/ filemap pages */
unsigned long file_pages; /* number of pages in the file*/
unsigned long bytes; /* total bytes in the bitmap */
+ unsigned long sb_index; /* sb page index */
} storage;
unsigned long flags;
--
2.33.0
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