diff options
Diffstat (limited to 'fs/buffer.c')
| -rw-r--r-- | fs/buffer.c | 130 |
1 files changed, 84 insertions, 46 deletions
diff --git a/fs/buffer.c b/fs/buffer.c index b205a629001d..0e87401cf335 100644 --- a/fs/buffer.c +++ b/fs/buffer.c @@ -43,6 +43,7 @@ #include <linux/bitops.h> #include <linux/mpage.h> #include <linux/bit_spinlock.h> +#include <linux/pagevec.h> #include <trace/events/block.h> static int fsync_buffers_list(spinlock_t *lock, struct list_head *list); @@ -753,7 +754,7 @@ static int fsync_buffers_list(spinlock_t *lock, struct list_head *list) * still in flight on potentially older * contents. */ - write_dirty_buffer(bh, WRITE_SYNC); + write_dirty_buffer(bh, REQ_SYNC); /* * Kick off IO for the previous mapping. Note @@ -1604,37 +1605,80 @@ void create_empty_buffers(struct page *page, } EXPORT_SYMBOL(create_empty_buffers); -/* - * We are taking a block for data and we don't want any output from any - * buffer-cache aliases starting from return from that function and - * until the moment when something will explicitly mark the buffer - * dirty (hopefully that will not happen until we will free that block ;-) - * We don't even need to mark it not-uptodate - nobody can expect - * anything from a newly allocated buffer anyway. We used to used - * unmap_buffer() for such invalidation, but that was wrong. We definitely - * don't want to mark the alias unmapped, for example - it would confuse - * anyone who might pick it with bread() afterwards... - * - * Also.. Note that bforget() doesn't lock the buffer. So there can - * be writeout I/O going on against recently-freed buffers. We don't - * wait on that I/O in bforget() - it's more efficient to wait on the I/O - * only if we really need to. That happens here. - */ -void unmap_underlying_metadata(struct block_device *bdev, sector_t block) +/** + * clean_bdev_aliases: clean a range of buffers in block device + * @bdev: Block device to clean buffers in + * @block: Start of a range of blocks to clean + * @len: Number of blocks to clean + * + * We are taking a range of blocks for data and we don't want writeback of any + * buffer-cache aliases starting from return from this function and until the + * moment when something will explicitly mark the buffer dirty (hopefully that + * will not happen until we will free that block ;-) We don't even need to mark + * it not-uptodate - nobody can expect anything from a newly allocated buffer + * anyway. We used to use unmap_buffer() for such invalidation, but that was + * wrong. We definitely don't want to mark the alias unmapped, for example - it + * would confuse anyone who might pick it with bread() afterwards... + * + * Also.. Note that bforget() doesn't lock the buffer. So there can be + * writeout I/O going on against recently-freed buffers. We don't wait on that + * I/O in bforget() - it's more efficient to wait on the I/O only if we really + * need to. That happens here. + */ +void clean_bdev_aliases(struct block_device *bdev, sector_t block, sector_t len) { - struct buffer_head *old_bh; + struct inode *bd_inode = bdev->bd_inode; + struct address_space *bd_mapping = bd_inode->i_mapping; + struct pagevec pvec; + pgoff_t index = block >> (PAGE_SHIFT - bd_inode->i_blkbits); + pgoff_t end; + int i; + struct buffer_head *bh; + struct buffer_head *head; - might_sleep(); + end = (block + len - 1) >> (PAGE_SHIFT - bd_inode->i_blkbits); + pagevec_init(&pvec, 0); + while (index <= end && pagevec_lookup(&pvec, bd_mapping, index, + min(end - index, (pgoff_t)PAGEVEC_SIZE - 1) + 1)) { + for (i = 0; i < pagevec_count(&pvec); i++) { + struct page *page = pvec.pages[i]; - old_bh = __find_get_block_slow(bdev, block); - if (old_bh) { - clear_buffer_dirty(old_bh); - wait_on_buffer(old_bh); - clear_buffer_req(old_bh); - __brelse(old_bh); + index = page->index; + if (index > end) + break; + if (!page_has_buffers(page)) + continue; + /* + * We use page lock instead of bd_mapping->private_lock + * to pin buffers here since we can afford to sleep and + * it scales better than a global spinlock lock. + */ + lock_page(page); + /* Recheck when the page is locked which pins bhs */ + if (!page_has_buffers(page)) + goto unlock_page; + head = page_buffers(page); + bh = head; + do { + if (!buffer_mapped(bh) || (bh->b_blocknr < block)) + goto next; + if (bh->b_blocknr >= block + len) + break; + clear_buffer_dirty(bh); + wait_on_buffer(bh); + clear_buffer_req(bh); +next: + bh = bh->b_this_page; + } while (bh != head); +unlock_page: + unlock_page(page); + } + pagevec_release(&pvec); + cond_resched(); + index++; } } -EXPORT_SYMBOL(unmap_underlying_metadata); +EXPORT_SYMBOL(clean_bdev_aliases); /* * Size is a power-of-two in the range 512..PAGE_SIZE, @@ -1684,7 +1728,7 @@ static struct buffer_head *create_page_buffers(struct page *page, struct inode * * prevents this contention from occurring. * * If block_write_full_page() is called with wbc->sync_mode == - * WB_SYNC_ALL, the writes are posted using WRITE_SYNC; this + * WB_SYNC_ALL, the writes are posted using REQ_SYNC; this * causes the writes to be flagged as synchronous writes. */ int __block_write_full_page(struct inode *inode, struct page *page, @@ -1697,7 +1741,7 @@ int __block_write_full_page(struct inode *inode, struct page *page, struct buffer_head *bh, *head; unsigned int blocksize, bbits; int nr_underway = 0; - int write_flags = (wbc->sync_mode == WB_SYNC_ALL ? WRITE_SYNC : 0); + int write_flags = wbc_to_write_flags(wbc); head = create_page_buffers(page, inode, (1 << BH_Dirty)|(1 << BH_Uptodate)); @@ -1745,8 +1789,7 @@ int __block_write_full_page(struct inode *inode, struct page *page, if (buffer_new(bh)) { /* blockdev mappings never come here */ clear_buffer_new(bh); - unmap_underlying_metadata(bh->b_bdev, - bh->b_blocknr); + clean_bdev_bh_alias(bh); } } bh = bh->b_this_page; @@ -1992,8 +2035,7 @@ int __block_write_begin_int(struct page *page, loff_t pos, unsigned len, } if (buffer_new(bh)) { - unmap_underlying_metadata(bh->b_bdev, - bh->b_blocknr); + clean_bdev_bh_alias(bh); if (PageUptodate(page)) { clear_buffer_new(bh); set_buffer_uptodate(bh); @@ -2633,7 +2675,7 @@ int nobh_write_begin(struct address_space *mapping, if (!buffer_mapped(bh)) is_mapped_to_disk = 0; if (buffer_new(bh)) - unmap_underlying_metadata(bh->b_bdev, bh->b_blocknr); + clean_bdev_bh_alias(bh); if (PageUptodate(page)) { set_buffer_uptodate(bh); continue; @@ -3118,7 +3160,7 @@ EXPORT_SYMBOL(submit_bh); /** * ll_rw_block: low-level access to block devices (DEPRECATED) * @op: whether to %READ or %WRITE - * @op_flags: rq_flag_bits + * @op_flags: req_flag_bits * @nr: number of &struct buffer_heads in the array * @bhs: array of pointers to &struct buffer_head * @@ -3210,7 +3252,7 @@ EXPORT_SYMBOL(__sync_dirty_buffer); int sync_dirty_buffer(struct buffer_head *bh) { - return __sync_dirty_buffer(bh, WRITE_SYNC); + return __sync_dirty_buffer(bh, REQ_SYNC); } EXPORT_SYMBOL(sync_dirty_buffer); @@ -3403,7 +3445,7 @@ void free_buffer_head(struct buffer_head *bh) } EXPORT_SYMBOL(free_buffer_head); -static void buffer_exit_cpu(int cpu) +static int buffer_exit_cpu_dead(unsigned int cpu) { int i; struct bh_lru *b = &per_cpu(bh_lrus, cpu); @@ -3414,14 +3456,7 @@ static void buffer_exit_cpu(int cpu) } this_cpu_add(bh_accounting.nr, per_cpu(bh_accounting, cpu).nr); per_cpu(bh_accounting, cpu).nr = 0; -} - -static int buffer_cpu_notify(struct notifier_block *self, - unsigned long action, void *hcpu) -{ - if (action == CPU_DEAD || action == CPU_DEAD_FROZEN) - buffer_exit_cpu((unsigned long)hcpu); - return NOTIFY_OK; + return 0; } /** @@ -3471,6 +3506,7 @@ EXPORT_SYMBOL(bh_submit_read); void __init buffer_init(void) { unsigned long nrpages; + int ret; bh_cachep = kmem_cache_create("buffer_head", sizeof(struct buffer_head), 0, @@ -3483,5 +3519,7 @@ void __init buffer_init(void) */ nrpages = (nr_free_buffer_pages() * 10) / 100; max_buffer_heads = nrpages * (PAGE_SIZE / sizeof(struct buffer_head)); - hotcpu_notifier(buffer_cpu_notify, 0); + ret = cpuhp_setup_state_nocalls(CPUHP_FS_BUFF_DEAD, "fs/buffer:dead", + NULL, buffer_exit_cpu_dead); + WARN_ON(ret < 0); } |