Skip to content

Commit

Permalink
md/bitmap: centralise allocation of bitmap file pages.
Browse files Browse the repository at this point in the history 
Instead of allocating pages in read_sb_page, read_page and
bitmap_read_sb, allocate them all in bitmap_init_from disk.

Also replace the hack of calling "attach_page_buffers(page, NULL)" to
ensure that free_buffer() won't complain, by putting a test for
PagePrivate in free_buffer().

Signed-off-by: NeilBrown <neilb@suse.de>
  • Loading branch information
NeilBrown committed May 22, 2012
1 parent ef99bf4 commit 27581e5
Showing 1 changed file with 68 additions and 81 deletions.
149 changes: 68 additions & 81 deletions drivers/md/bitmap.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -130,22 +130,14 @@ static void bitmap_checkfree(struct bitmap *bitmap, unsigned long page)
*/

/* IO operations when bitmap is stored near all superblocks */
static struct page *read_sb_page(struct mddev *mddev, loff_t offset,
struct page *page,
unsigned long index, int size)
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;
int did_alloc = 0;

if (!page) {
page = alloc_page(GFP_KERNEL);
if (!page)
return ERR_PTR(-ENOMEM);
did_alloc = 1;
}

rdev_for_each(rdev, mddev) {
if (! test_bit(In_sync, &rdev->flags)
Expand All @@ -158,15 +150,10 @@ static struct page *read_sb_page(struct mddev *mddev, loff_t offset,
roundup(size, bdev_logical_block_size(rdev->bdev)),
page, READ, true)) {
page->index = index;
attach_page_buffers(page, NULL); /* so that free_buffer will
* quietly no-op */
return page;
return 0;
}
}
if (did_alloc)
put_page(page);
return ERR_PTR(-EIO);

return -EIO;
}

static struct md_rdev *next_active_rdev(struct md_rdev *rdev, struct mddev *mddev)
Expand Down Expand Up @@ -325,8 +312,12 @@ __clear_page_buffers(struct page *page)
}
static void free_buffers(struct page *page)
{
struct buffer_head *bh = page_buffers(page);
struct buffer_head *bh;

if (!PagePrivate(page))
return;

bh = page_buffers(page);
while (bh) {
struct buffer_head *next = bh->b_this_page;
free_buffer_head(bh);
Expand All @@ -343,28 +334,22 @@ static void free_buffers(struct page *page)
* This usage is similar to how swap files are handled, and allows us
* to write to a file with no concerns of memory allocation failing.
*/
static struct page *read_page(struct file *file, unsigned long index,
struct bitmap *bitmap,
unsigned long count)
static int read_page(struct file *file, unsigned long index,
struct bitmap *bitmap,
unsigned long count,
struct page *page)
{
struct page *page = NULL;
int ret = 0;
struct inode *inode = file->f_path.dentry->d_inode;
struct buffer_head *bh;
sector_t block;

pr_debug("read bitmap file (%dB @ %llu)\n", (int)PAGE_SIZE,
(unsigned long long)index << PAGE_SHIFT);

page = alloc_page(GFP_KERNEL);
if (!page)
page = ERR_PTR(-ENOMEM);
if (IS_ERR(page))
goto out;

bh = alloc_page_buffers(page, 1<<inode->i_blkbits, 0);
if (!bh) {
put_page(page);
page = ERR_PTR(-ENOMEM);
ret = -ENOMEM;
goto out;
}
attach_page_buffers(page, bh);
Expand All @@ -376,8 +361,7 @@ static struct page *read_page(struct file *file, unsigned long index,
bh->b_blocknr = bmap(inode, block);
if (bh->b_blocknr == 0) {
/* Cannot use this file! */
free_buffers(page);
page = ERR_PTR(-EINVAL);
ret = -EINVAL;
goto out;
}
bh->b_bdev = inode->i_sb->s_bdev;
Expand All @@ -400,17 +384,15 @@ static struct page *read_page(struct file *file, unsigned long index,

wait_event(bitmap->write_wait,
atomic_read(&bitmap->pending_writes)==0);
if (bitmap->flags & BITMAP_WRITE_ERROR) {
free_buffers(page);
page = ERR_PTR(-EIO);
}
if (bitmap->flags & BITMAP_WRITE_ERROR)
ret = -EIO;
out:
if (IS_ERR(page))
printk(KERN_ALERT "md: bitmap read error: (%dB @ %llu): %ld\n",
if (ret)
printk(KERN_ALERT "md: bitmap read error: (%dB @ %llu): %d\n",
(int)PAGE_SIZE,
(unsigned long long)index << PAGE_SHIFT,
PTR_ERR(page));
return page;
ret);
return ret;
}

/*
Expand Down Expand Up @@ -552,6 +534,7 @@ static int bitmap_read_sb(struct bitmap *bitmap)
unsigned long chunksize, daemon_sleep, write_behind;
unsigned long long events;
int err = -EINVAL;
struct page *sb_page;

if (!bitmap->file && !bitmap->mddev->bitmap_info.offset) {
chunksize = 128 * 1024 * 1024;
Expand All @@ -562,24 +545,27 @@ static int bitmap_read_sb(struct bitmap *bitmap)
goto out_no_sb;
}
/* page 0 is the superblock, read it... */
sb_page = alloc_page(GFP_KERNEL);
if (!sb_page)
return -ENOMEM;
bitmap->sb_page = sb_page;

if (bitmap->file) {
loff_t isize = i_size_read(bitmap->file->f_mapping->host);
int bytes = isize > PAGE_SIZE ? PAGE_SIZE : isize;

bitmap->sb_page = read_page(bitmap->file, 0, bitmap, bytes);
err = read_page(bitmap->file, 0,
bitmap, bytes, sb_page);
} else {
bitmap->sb_page = read_sb_page(bitmap->mddev,
bitmap->mddev->bitmap_info.offset,
NULL,
0, sizeof(bitmap_super_t));
err = read_sb_page(bitmap->mddev,
bitmap->mddev->bitmap_info.offset,
sb_page,
0, sizeof(bitmap_super_t));
}
if (IS_ERR(bitmap->sb_page)) {
err = PTR_ERR(bitmap->sb_page);
bitmap->sb_page = NULL;
if (err)
return err;
}

sb = kmap_atomic(bitmap->sb_page);
sb = kmap_atomic(sb_page);

chunksize = le32_to_cpu(sb->chunksize);
daemon_sleep = le32_to_cpu(sb->daemon_sleep) * HZ;
Expand Down Expand Up @@ -948,7 +934,8 @@ static void bitmap_set_memory_bits(struct bitmap *bitmap, sector_t offset, int n
static int bitmap_init_from_disk(struct bitmap *bitmap, sector_t start)
{
unsigned long i, chunks, index, oldindex, bit;
struct page *page = NULL, *oldpage = NULL;
int pnum;
struct page *page = NULL;
unsigned long num_pages, bit_cnt = 0;
struct file *file;
unsigned long bytes, offset;
Expand Down Expand Up @@ -999,6 +986,22 @@ static int bitmap_init_from_disk(struct bitmap *bitmap, sector_t start)
if (!bitmap->filemap)
goto err;

pnum = 0;
offset = 0;
if (bitmap->sb_page) {
bitmap->filemap[0] = bitmap->sb_page;
pnum = 1;
offset = sizeof(bitmap_super_t);
}
for ( ; pnum < num_pages; pnum++) {
bitmap->filemap[pnum] = alloc_page(GFP_KERNEL);
if (!bitmap->filemap[pnum]) {
bitmap->file_pages = pnum;
goto err;
}
}
bitmap->file_pages = pnum;

/* We need 4 bits per page, rounded up to a multiple of sizeof(unsigned long) */
bitmap->filemap_attr = kzalloc(
roundup(DIV_ROUND_UP(num_pages*4, 8), sizeof(unsigned long)),
Expand All @@ -1019,39 +1022,22 @@ static int bitmap_init_from_disk(struct bitmap *bitmap, sector_t start)
count = bytes - index * PAGE_SIZE;
else
count = PAGE_SIZE;
if (index == 0 && bitmap->sb_page) {
/*
* if we're here then the superblock page
* contains some bits (PAGE_SIZE != sizeof sb)
* we've already read it in, so just use it
*/
page = bitmap->sb_page;
offset = sizeof(bitmap_super_t);
if (!file)
page = read_sb_page(
bitmap->mddev,
bitmap->mddev->bitmap_info.offset,
page,
index, count);
} else if (file) {
page = read_page(file, index, bitmap, count);
offset = 0;
} else {
page = read_sb_page(bitmap->mddev,
bitmap->mddev->bitmap_info.offset,
NULL,
index, count);
offset = 0;
}
if (IS_ERR(page)) { /* read error */
ret = PTR_ERR(page);
page = bitmap->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, count);

if (ret)
goto err;
}

oldindex = index;
oldpage = page;

bitmap->filemap[bitmap->file_pages++] = page;
bitmap->last_page_size = count;

if (outofdate) {
Expand Down Expand Up @@ -1085,6 +1071,7 @@ static int bitmap_init_from_disk(struct bitmap *bitmap, sector_t start)
needed);
bit_cnt++;
}
offset = 0;
}

printk(KERN_INFO "%s: bitmap initialized from disk: "
Expand Down

0 comments on commit 27581e5

Please sign in to comment.