#define BH_ENTRY(list) list_entry((list), struct buffer_head, b_assoc_buffers)
-inline void
-init_buffer(struct buffer_head *bh, bh_end_io_t *handler, void *private)
+void init_buffer(struct buffer_head *bh, bh_end_io_t *handler, void *private)
{
bh->b_end_io = handler;
bh->b_private = private;
*/
int sync_mapping_buffers(struct address_space *mapping)
{
- struct address_space *buffer_mapping = mapping->assoc_mapping;
+ struct address_space *buffer_mapping = mapping->private_data;
if (buffer_mapping == NULL || list_empty(&mapping->private_list))
return 0;
struct address_space *buffer_mapping = bh->b_page->mapping;
mark_buffer_dirty(bh);
- if (!mapping->assoc_mapping) {
- mapping->assoc_mapping = buffer_mapping;
+ if (!mapping->private_data) {
+ mapping->private_data = buffer_mapping;
} else {
- BUG_ON(mapping->assoc_mapping != buffer_mapping);
+ BUG_ON(mapping->private_data != buffer_mapping);
}
if (!bh->b_assoc_map) {
spin_lock(&buffer_mapping->private_lock);
if (inode_has_buffers(inode)) {
struct address_space *mapping = &inode->i_data;
struct list_head *list = &mapping->private_list;
- struct address_space *buffer_mapping = mapping->assoc_mapping;
+ struct address_space *buffer_mapping = mapping->private_data;
spin_lock(&buffer_mapping->private_lock);
while (!list_empty(list))
if (inode_has_buffers(inode)) {
struct address_space *mapping = &inode->i_data;
struct list_head *list = &mapping->private_list;
- struct address_space *buffer_mapping = mapping->assoc_mapping;
+ struct address_space *buffer_mapping = mapping->private_data;
spin_lock(&buffer_mapping->private_lock);
while (!list_empty(list)) {
if (!bh)
goto no_grow;
- bh->b_bdev = NULL;
bh->b_this_page = head;
bh->b_blocknr = -1;
head = bh;
- bh->b_state = 0;
- atomic_set(&bh->b_count, 0);
bh->b_size = size;
/* Link the buffer to its page */
attach_page_buffers(page, head);
}
+static sector_t blkdev_max_block(struct block_device *bdev, unsigned int size)
+{
+ sector_t retval = ~((sector_t)0);
+ loff_t sz = i_size_read(bdev->bd_inode);
+
+ if (sz) {
+ unsigned int sizebits = blksize_bits(size);
+ retval = (sz >> sizebits);
+ }
+ return retval;
+}
+
/*
* Initialise the state of a blockdev page's buffers.
*/
struct buffer_head *head = page_buffers(page);
struct buffer_head *bh = head;
int uptodate = PageUptodate(page);
- sector_t end_block = blkdev_max_block(I_BDEV(bdev->bd_inode));
+ sector_t end_block = blkdev_max_block(I_BDEV(bdev->bd_inode), size);
do {
if (!buffer_mapped(bh)) {
}
EXPORT_SYMBOL(unmap_underlying_metadata);
+/*
+ * Size is a power-of-two in the range 512..PAGE_SIZE,
+ * and the case we care about most is PAGE_SIZE.
+ *
+ * So this *could* possibly be written with those
+ * constraints in mind (relevant mostly if some
+ * architecture has a slow bit-scan instruction)
+ */
+static inline int block_size_bits(unsigned int blocksize)
+{
+ return ilog2(blocksize);
+}
+
+static struct buffer_head *create_page_buffers(struct page *page, struct inode *inode, unsigned int b_state)
+{
+ BUG_ON(!PageLocked(page));
+
+ if (!page_has_buffers(page))
+ create_empty_buffers(page, 1 << ACCESS_ONCE(inode->i_blkbits), b_state);
+ return page_buffers(page);
+}
+
/*
* NOTE! All mapped/uptodate combinations are valid:
*
sector_t block;
sector_t last_block;
struct buffer_head *bh, *head;
- const unsigned blocksize = 1 << inode->i_blkbits;
+ unsigned int blocksize, bbits;
int nr_underway = 0;
int write_op = (wbc->sync_mode == WB_SYNC_ALL ?
WRITE_SYNC : WRITE);
- BUG_ON(!PageLocked(page));
-
- last_block = (i_size_read(inode) - 1) >> inode->i_blkbits;
-
- if (!page_has_buffers(page)) {
- create_empty_buffers(page, blocksize,
+ head = create_page_buffers(page, inode,
(1 << BH_Dirty)|(1 << BH_Uptodate));
- }
/*
* Be very careful. We have no exclusion from __set_page_dirty_buffers
* handle that here by just cleaning them.
*/
- block = (sector_t)page->index << (PAGE_CACHE_SHIFT - inode->i_blkbits);
- head = page_buffers(page);
bh = head;
+ blocksize = bh->b_size;
+ bbits = block_size_bits(blocksize);
+
+ block = (sector_t)page->index << (PAGE_CACHE_SHIFT - bbits);
+ last_block = (i_size_read(inode) - 1) >> bbits;
/*
* Get all the dirty buffers mapped to disk addresses and
BUG_ON(to > PAGE_CACHE_SIZE);
BUG_ON(from > to);
- blocksize = 1 << inode->i_blkbits;
- if (!page_has_buffers(page))
- create_empty_buffers(page, blocksize, 0);
- head = page_buffers(page);
+ head = create_page_buffers(page, inode, 0);
+ blocksize = head->b_size;
+ bbits = block_size_bits(blocksize);
- bbits = inode->i_blkbits;
block = (sector_t)page->index << (PAGE_CACHE_SHIFT - bbits);
for(bh = head, block_start = 0; bh != head || !block_start;
unsigned blocksize;
struct buffer_head *bh, *head;
- blocksize = 1 << inode->i_blkbits;
+ bh = head = page_buffers(page);
+ blocksize = bh->b_size;
- for(bh = head = page_buffers(page), block_start = 0;
- bh != head || !block_start;
- block_start=block_end, bh = bh->b_this_page) {
+ block_start = 0;
+ do {
block_end = block_start + blocksize;
if (block_end <= from || block_start >= to) {
if (!buffer_uptodate(bh))
mark_buffer_dirty(bh);
}
clear_buffer_new(bh);
- }
+
+ block_start = block_end;
+ bh = bh->b_this_page;
+ } while (bh != head);
/*
* If this is a partial write which happened to make all buffers
int block_is_partially_uptodate(struct page *page, read_descriptor_t *desc,
unsigned long from)
{
- struct inode *inode = page->mapping->host;
unsigned block_start, block_end, blocksize;
unsigned to;
struct buffer_head *bh, *head;
if (!page_has_buffers(page))
return 0;
- blocksize = 1 << inode->i_blkbits;
+ head = page_buffers(page);
+ blocksize = head->b_size;
to = min_t(unsigned, PAGE_CACHE_SIZE - from, desc->count);
to = from + to;
if (from < blocksize && to > PAGE_CACHE_SIZE - blocksize)
return 0;
- head = page_buffers(page);
bh = head;
block_start = 0;
do {
struct inode *inode = page->mapping->host;
sector_t iblock, lblock;
struct buffer_head *bh, *head, *arr[MAX_BUF_PER_PAGE];
- unsigned int blocksize;
+ unsigned int blocksize, bbits;
int nr, i;
int fully_mapped = 1;
- BUG_ON(!PageLocked(page));
- blocksize = 1 << inode->i_blkbits;
- if (!page_has_buffers(page))
- create_empty_buffers(page, blocksize, 0);
- head = page_buffers(page);
+ head = create_page_buffers(page, inode, 0);
+ blocksize = head->b_size;
+ bbits = block_size_bits(blocksize);
- iblock = (sector_t)page->index << (PAGE_CACHE_SHIFT - inode->i_blkbits);
- lblock = (i_size_read(inode)+blocksize-1) >> inode->i_blkbits;
+ iblock = (sector_t)page->index << (PAGE_CACHE_SHIFT - bbits);
+ lblock = (i_size_read(inode)+blocksize-1) >> bbits;
bh = head;
nr = 0;
i = 0;
bio_put(bio);
}
+/*
+ * This allows us to do IO even on the odd last sectors
+ * of a device, even if the bh block size is some multiple
+ * of the physical sector size.
+ *
+ * We'll just truncate the bio to the size of the device,
+ * and clear the end of the buffer head manually.
+ *
+ * Truly out-of-range accesses will turn into actual IO
+ * errors, this only handles the "we need to be able to
+ * do IO at the final sector" case.
+ */
+static void guard_bh_eod(int rw, struct bio *bio, struct buffer_head *bh)
+{
+ sector_t maxsector;
+ unsigned bytes;
+
+ maxsector = i_size_read(bio->bi_bdev->bd_inode) >> 9;
+ if (!maxsector)
+ return;
+
+ /*
+ * If the *whole* IO is past the end of the device,
+ * let it through, and the IO layer will turn it into
+ * an EIO.
+ */
+ if (unlikely(bio->bi_sector >= maxsector))
+ return;
+
+ maxsector -= bio->bi_sector;
+ bytes = bio->bi_size;
+ if (likely((bytes >> 9) <= maxsector))
+ return;
+
+ /* Uhhuh. We've got a bh that straddles the device size! */
+ bytes = maxsector << 9;
+
+ /* Truncate the bio.. */
+ bio->bi_size = bytes;
+ bio->bi_io_vec[0].bv_len = bytes;
+
+ /* ..and clear the end of the buffer for reads */
+ if ((rw & RW_MASK) == READ) {
+ void *kaddr = kmap_atomic(bh->b_page);
+ memset(kaddr + bh_offset(bh) + bytes, 0, bh->b_size - bytes);
+ kunmap_atomic(kaddr);
+ }
+}
+
int submit_bh(int rw, struct buffer_head * bh)
{
struct bio *bio;
bio->bi_end_io = end_bio_bh_io_sync;
bio->bi_private = bh;
+ /* Take care of bh's that straddle the end of the device */
+ guard_bh_eod(rw, bio, bh);
+
bio_get(bio);
submit_bio(rw, bio);
projects / can-eth-gw-linux.git / blobdiff