Commit 205f87f6 authored by Badari Pulavarty's avatar Badari Pulavarty Committed by Linus Torvalds
Browse files

[PATCH] change buffer_head.b_size to size_t 



Increase the size of the buffer_head b_size field (only) for 64 bit platforms.
Update some old and moldy comments in and around the structure as well.

The b_size increase allows us to perform larger mappings and allocations for
large I/O requests from userspace, which tie in with other changes allowing
the get_block_t() interface to map multiple blocks at once.

Signed-off-by: default avatarNathan Scott <nathans@sgi.com>
Signed-off-by: default avatarBadari Pulavarty <pbadari@us.ibm.com>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent d48589bf

fs/buffer.c

+4 −2
Original line number Diff line number Diff line
@@ -426,8 +426,10 @@ __find_get_block_slow(struct block_device *bdev, sector_t block) 
	if (all_mapped) {

		printk("__find_get_block_slow() failed. "

			"block=%llu, b_blocknr=%llu\n",

			(unsigned long long)block, (unsigned long long)bh->b_blocknr);

		printk("b_state=0x%08lx, b_size=%u\n", bh->b_state, bh->b_size);

			(unsigned long long)block,

			(unsigned long long)bh->b_blocknr);

		printk("b_state=0x%08lx, b_size=%zu\n",

			bh->b_state, bh->b_size);

		printk("device blocksize: %d\n", 1 << bd_inode->i_blkbits);

	}

out_unlock:

fs/ocfs2/journal.c

+1 −1
Original line number Diff line number Diff line
@@ -377,7 +377,7 @@ int ocfs2_journal_access(struct ocfs2_journal_handle *handle, 
	BUG_ON(!bh);

	BUG_ON(!(handle->flags & OCFS2_HANDLE_STARTED));



	mlog_entry("bh->b_blocknr=%llu, type=%d (\"%s\"), bh->b_size = %hu\n",

	mlog_entry("bh->b_blocknr=%llu, type=%d (\"%s\"), bh->b_size = %zu\n",

		   (unsigned long long)bh->b_blocknr, type,

		   (type == OCFS2_JOURNAL_ACCESS_CREATE) ?

		   "OCFS2_JOURNAL_ACCESS_CREATE" :

fs/reiserfs/prints.c

+1 −1
Original line number Diff line number Diff line
@@ -143,7 +143,7 @@ static void sprintf_buffer_head(char *buf, struct buffer_head *bh) 
	char b[BDEVNAME_SIZE];



	sprintf(buf,

		"dev %s, size %d, blocknr %llu, count %d, state 0x%lx, page %p, (%s, %s, %s)",

		"dev %s, size %zd, blocknr %llu, count %d, state 0x%lx, page %p, (%s, %s, %s)",

		bdevname(bh->b_bdev, b), bh->b_size,

		(unsigned long long)bh->b_blocknr, atomic_read(&(bh->b_count)),

		bh->b_state, bh->b_page,

include/linux/buffer_head.h

+11 −8
Original line number Diff line number Diff line
@@ -46,25 +46,28 @@ struct address_space; 
typedef void (bh_end_io_t)(struct buffer_head *bh, int uptodate);



/*

 * Keep related fields in common cachelines.  The most commonly accessed

 * field (b_state) goes at the start so the compiler does not generate

 * indexed addressing for it.

 * Historically, a buffer_head was used to map a single block

 * within a page, and of course as the unit of I/O through the

 * filesystem and block layers.  Nowadays the basic I/O unit

 * is the bio, and buffer_heads are used for extracting block

 * mappings (via a get_block_t call), for tracking state within

 * a page (via a page_mapping) and for wrapping bio submission

 * for backward compatibility reasons (e.g. submit_bh).

 */

struct buffer_head {

	/* First cache line: */

	unsigned long b_state;		/* buffer state bitmap (see above) */

	struct buffer_head *b_this_page;/* circular list of page's buffers */

	struct page *b_page;		/* the page this bh is mapped to */

	atomic_t b_count;		/* users using this block */

	u32 b_size;			/* block size */



	sector_t b_blocknr;		/* block number */

	char *b_data;			/* pointer to data block */

	sector_t b_blocknr;		/* start block number */

	size_t b_size;			/* size of mapping */

	char *b_data;			/* pointer to data within the page */



	struct block_device *b_bdev;

	bh_end_io_t *b_end_io;		/* I/O completion */

 	void *b_private;		/* reserved for b_end_io */

	struct list_head b_assoc_buffers; /* associated with another mapping */

	atomic_t b_count;		/* users using this buffer_head */

};



/*

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