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.
Unified · Split
| @@ -426,8 +426,10 @@ __find_get_block_slow(struct block_device *bdev, sector_t block) · 425 unmodified lines | |||
| 426 | if (all_mapped) { | 426 | if (all_mapped) { |
| 427 | printk("__find_get_block_slow() failed. " | 427 | printk("__find_get_block_slow() failed. " |
| 428 | "block=%llu, b_blocknr=%llu\n", | 428 | "block=%llu, b_blocknr=%llu\n", |
| 429 | (unsigned long long)block, (unsigned long long)bh->b_blocknr); | 429 | (unsigned long long)block, |
| 430 | printk("b_state=0x%08lx, b_size=%u\n", bh->b_state, bh->b_size); | 430 | (unsigned long long)bh->b_blocknr); |
| 431 | printk("b_state=0x%08lx, b_size=%zu\n", | ||
| 432 | bh->b_state, bh->b_size); | ||
| 431 | printk("device blocksize: %d\n", 1 << bd_inode->i_blkbits); | 433 | printk("device blocksize: %d\n", 1 << bd_inode->i_blkbits); |
| 432 | } | 434 | } |
| 433 | out_unlock: | 435 | out_unlock: |
| @@ -377,7 +377,7 @@ int ocfs2_journal_access(struct ocfs2_journal_handle *handle, · 376 unmodified lines | |||
| 377 | BUG_ON(!bh); | 377 | BUG_ON(!bh); |
| 378 | BUG_ON(!(handle->flags & OCFS2_HANDLE_STARTED)); | 378 | BUG_ON(!(handle->flags & OCFS2_HANDLE_STARTED)); |
| 379 | 379 | ||
| 380 | mlog_entry("bh->b_blocknr=%llu, type=%d (\"%s\"), bh->b_size = %hu\n", | 380 | mlog_entry("bh->b_blocknr=%llu, type=%d (\"%s\"), bh->b_size = %zu\n", |
| 381 | (unsigned long long)bh->b_blocknr, type, | 381 | (unsigned long long)bh->b_blocknr, type, |
| 382 | (type == OCFS2_JOURNAL_ACCESS_CREATE) ? | 382 | (type == OCFS2_JOURNAL_ACCESS_CREATE) ? |
| 383 | "OCFS2_JOURNAL_ACCESS_CREATE" : | 383 | "OCFS2_JOURNAL_ACCESS_CREATE" : |
| @@ -143,7 +143,7 @@ static void sprintf_buffer_head(char *buf, struct buffer_head *bh) · 142 unmodified lines | |||
| 143 | char b[BDEVNAME_SIZE]; | 143 | char b[BDEVNAME_SIZE]; |
| 144 | 144 | ||
| 145 | sprintf(buf, | 145 | sprintf(buf, |
| 146 | "dev %s, size %d, blocknr %llu, count %d, state 0x%lx, page %p, (%s, %s, %s)", | 146 | "dev %s, size %zd, blocknr %llu, count %d, state 0x%lx, page %p, (%s, %s, %s)", |
| 147 | bdevname(bh->b_bdev, b), bh->b_size, | 147 | bdevname(bh->b_bdev, b), bh->b_size, |
| 148 | (unsigned long long)bh->b_blocknr, atomic_read(&(bh->b_count)), | 148 | (unsigned long long)bh->b_blocknr, atomic_read(&(bh->b_count)), |
| 149 | bh->b_state, bh->b_page, | 149 | bh->b_state, bh->b_page, |
| @@ -46,25 +46,28 @@ struct address_space; · 45 unmodified lines | |||
| 46 | typedef void (bh_end_io_t)(struct buffer_head *bh, int uptodate); | 46 | typedef void (bh_end_io_t)(struct buffer_head *bh, int uptodate); |
| 47 | 47 | ||
| 48 | /* | 48 | /* |
| 49 | * Keep related fields in common cachelines. The most commonly accessed | 49 | * Historically, a buffer_head was used to map a single block |
| 50 | * field (b_state) goes at the start so the compiler does not generate | 50 | * within a page, and of course as the unit of I/O through the |
| 51 | * indexed addressing for it. | 51 | * filesystem and block layers. Nowadays the basic I/O unit |
| 52 | * is the bio, and buffer_heads are used for extracting block | ||
| 53 | * mappings (via a get_block_t call), for tracking state within | ||
| 54 | * a page (via a page_mapping) and for wrapping bio submission | ||
| 55 | * for backward compatibility reasons (e.g. submit_bh). | ||
| 52 | */ | 56 | */ |
| 53 | struct buffer_head { | 57 | struct buffer_head { |
| 54 | /* First cache line: */ | ||
| 55 | unsigned long b_state; /* buffer state bitmap (see above) */ | 58 | unsigned long b_state; /* buffer state bitmap (see above) */ |
| 56 | struct buffer_head *b_this_page;/* circular list of page's buffers */ | 59 | struct buffer_head *b_this_page;/* circular list of page's buffers */ |
| 57 | struct page *b_page; /* the page this bh is mapped to */ | 60 | struct page *b_page; /* the page this bh is mapped to */ |
| 58 | atomic_t b_count; /* users using this block */ | ||
| 59 | u32 b_size; /* block size */ | ||
| 60 | 61 | ||
| 61 | sector_t b_blocknr; /* block number */ | 62 | sector_t b_blocknr; /* start block number */ |
| 62 | char *b_data; /* pointer to data block */ | 63 | size_t b_size; /* size of mapping */ |
| 64 | char *b_data; /* pointer to data within the page */ | ||
| 63 | 65 | ||
| 64 | struct block_device *b_bdev; | 66 | struct block_device *b_bdev; |
| 65 | bh_end_io_t *b_end_io; /* I/O completion */ | 67 | bh_end_io_t *b_end_io; /* I/O completion */ |
| 66 | void *b_private; /* reserved for b_end_io */ | 68 | void *b_private; /* reserved for b_end_io */ |
| 67 | struct list_head b_assoc_buffers; /* associated with another mapping */ | 69 | struct list_head b_assoc_buffers; /* associated with another mapping */ |
| 70 | atomic_t b_count; /* users using this buffer_head */ | ||
| 68 | }; | 71 | }; |
| 69 | 72 | ||
| 70 | /* | 73 | /* |