ocfs2: teach ocfs2_file_aio_write() about sparse files (9517bac6) · Commits · 戴 / test

fs/ocfs2/aops.c

+663 −16

Original line number	Diff line number	Diff line
		@@ -24,6 +24,7 @@
		#include <linux/highmem.h>
		#include <linux/pagemap.h>
		#include <asm/byteorder.h>
		#include <linux/swap.h>

		#define MLOG_MASK_PREFIX ML_FILE_IO
		#include <cluster/masklog.h>
		@@ -37,6 +38,7 @@
		#include "file.h"
		#include "inode.h"
		#include "journal.h"
		#include "suballoc.h"
		#include "super.h"
		#include "symlink.h"

		@@ -645,16 +647,19 @@ static ssize_t ocfs2_direct_IO(int rw,

		mlog_entry_void();

		if (!ocfs2_sparse_alloc(OCFS2_SB(inode->i_sb))) {
		/*
		* We get PR data locks even for O_DIRECT. This allows
		* concurrent O_DIRECT I/O but doesn't let O_DIRECT with
		* extending and buffered zeroing writes race. If they did
		* race then the buffered zeroing could be written back after
		* the O_DIRECT I/O. It's one thing to tell people not to mix
		* buffered and O_DIRECT writes, but expecting them to
		* understand that file extension is also an implicit buffered
		* write is too much. By getting the PR we force writeback of
		* the buffered zeroing before proceeding.
		* We get PR data locks even for O_DIRECT. This
		* allows concurrent O_DIRECT I/O but doesn't let
		* O_DIRECT with extending and buffered zeroing writes
		* race. If they did race then the buffered zeroing
		* could be written back after the O_DIRECT I/O. It's
		* one thing to tell people not to mix buffered and
		* O_DIRECT writes, but expecting them to understand
		* that file extension is also an implicit buffered
		* write is too much. By getting the PR we force
		* writeback of the buffered zeroing before
		* proceeding.
		*/
		ret = ocfs2_data_lock(inode, 0);
		if (ret < 0) {
		@@ -662,6 +667,7 @@ static ssize_t ocfs2_direct_IO(int rw,
		goto out;
		}
		ocfs2_data_unlock(inode, 0);
		}

		ret = blockdev_direct_IO_no_locking(rw, iocb, inode,
		inode->i_sb->s_bdev, iov, offset,
		@@ -673,6 +679,647 @@ out:
		return ret;
		}

		static void ocfs2_figure_cluster_boundaries(struct ocfs2_super *osb,
		u32 cpos,
		unsigned int *start,
		unsigned int *end)
		{
		unsigned int cluster_start = 0, cluster_end = PAGE_CACHE_SIZE;

		if (unlikely(PAGE_CACHE_SHIFT > osb->s_clustersize_bits)) {
		unsigned int cpp;

		cpp = 1 << (PAGE_CACHE_SHIFT - osb->s_clustersize_bits);

		cluster_start = cpos % cpp;
		cluster_start = cluster_start << osb->s_clustersize_bits;

		cluster_end = cluster_start + osb->s_clustersize;
		}

		BUG_ON(cluster_start > PAGE_SIZE);
		BUG_ON(cluster_end > PAGE_SIZE);

		if (start)
		*start = cluster_start;
		if (end)
		*end = cluster_end;
		}

		/*
		* 'from' and 'to' are the region in the page to avoid zeroing.
		*
		* If pagesize > clustersize, this function will avoid zeroing outside
		* of the cluster boundary.
		*
		* from == to == 0 is code for "zero the entire cluster region"
		*/
		static void ocfs2_clear_page_regions(struct page *page,
		struct ocfs2_super *osb, u32 cpos,
		unsigned from, unsigned to)
		{
		void *kaddr;
		unsigned int cluster_start, cluster_end;

		ocfs2_figure_cluster_boundaries(osb, cpos, &cluster_start, &cluster_end);

		kaddr = kmap_atomic(page, KM_USER0);

		if (from \|\| to) {
		if (from > cluster_start)
		memset(kaddr + cluster_start, 0, from - cluster_start);
		if (to < cluster_end)
		memset(kaddr + to, 0, cluster_end - to);
		} else {
		memset(kaddr + cluster_start, 0, cluster_end - cluster_start);
		}

		kunmap_atomic(kaddr, KM_USER0);
		}

		/*
		* Some of this taken from block_prepare_write(). We already have our
		* mapping by now though, and the entire write will be allocating or
		* it won't, so not much need to use BH_New.
		*
		* This will also skip zeroing, which is handled externally.
		*/
		static int ocfs2_map_page_blocks(struct page page, u64 p_blkno,
		struct inode *inode, unsigned int from,
		unsigned int to, int new)
		{
		int ret = 0;
		struct buffer_head head, bh, wait[2], *wait_bh = wait;
		unsigned int block_end, block_start;
		unsigned int bsize = 1 << inode->i_blkbits;

		if (!page_has_buffers(page))
		create_empty_buffers(page, bsize, 0);

		head = page_buffers(page);
		for (bh = head, block_start = 0; bh != head \|\| !block_start;
		bh = bh->b_this_page, block_start += bsize) {
		block_end = block_start + bsize;

		/*
		* Ignore blocks outside of our i/o range -
		* they may belong to unallocated clusters.
		*/
		if (block_start >= to \|\|
		(block_start + bsize) <= from) {
		if (PageUptodate(page))
		set_buffer_uptodate(bh);
		continue;
		}

		/*
		* For an allocating write with cluster size >= page
		* size, we always write the entire page.
		*/

		if (buffer_new(bh))
		clear_buffer_new(bh);

		if (!buffer_mapped(bh)) {
		map_bh(bh, inode->i_sb, *p_blkno);
		unmap_underlying_metadata(bh->b_bdev, bh->b_blocknr);
		}

		if (PageUptodate(page)) {
		if (!buffer_uptodate(bh))
		set_buffer_uptodate(bh);
		} else if (!buffer_uptodate(bh) && !buffer_delay(bh) &&
		(block_start < from \|\| block_end > to)) {
		ll_rw_block(READ, 1, &bh);
		*wait_bh++=bh;
		}

		p_blkno = p_blkno + 1;
		}

		/*
		* If we issued read requests - let them complete.
		*/
		while(wait_bh > wait) {
		wait_on_buffer(*--wait_bh);
		if (!buffer_uptodate(*wait_bh))
		ret = -EIO;
		}

		if (ret == 0 \|\| !new)
		return ret;

		/*
		* If we get -EIO above, zero out any newly allocated blocks
		* to avoid exposing stale data.
		*/
		bh = head;
		block_start = 0;
		do {
		void *kaddr;

		block_end = block_start + bsize;
		if (block_end <= from)
		goto next_bh;
		if (block_start >= to)
		break;

		kaddr = kmap_atomic(page, KM_USER0);
		memset(kaddr+block_start, 0, bh->b_size);
		flush_dcache_page(page);
		kunmap_atomic(kaddr, KM_USER0);
		set_buffer_uptodate(bh);
		mark_buffer_dirty(bh);

		next_bh:
		block_start = block_end;
		bh = bh->b_this_page;
		} while (bh != head);

		return ret;
		}

		/*
		* This will copy user data from the iovec in the buffered write
		* context.
		*/
		int ocfs2_map_and_write_user_data(struct inode *inode,
		struct ocfs2_write_ctxt wc, u64 p_blkno,
		unsigned int ret_from, unsigned int ret_to)
		{
		int ret;
		unsigned int to, from, cluster_start, cluster_end;
		unsigned long bytes, src_from;
		char *dst;
		struct ocfs2_buffered_write_priv *bp = wc->w_private;
		const struct iovec *cur_iov = bp->b_cur_iov;
		char __user *buf;
		struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);

		ocfs2_figure_cluster_boundaries(osb, wc->w_cpos, &cluster_start,
		&cluster_end);

		buf = cur_iov->iov_base + bp->b_cur_off;
		src_from = (unsigned long)buf & ~PAGE_CACHE_MASK;

		from = wc->w_pos & (PAGE_CACHE_SIZE - 1);

		/*
		* This is a lot of comparisons, but it reads quite
		* easily, which is important here.
		*/
		/* Stay within the src page */
		bytes = PAGE_SIZE - src_from;
		/* Stay within the vector */
		bytes = min(bytes,
		(unsigned long)(cur_iov->iov_len - bp->b_cur_off));
		/* Stay within count */
		bytes = min(bytes, (unsigned long)wc->w_count);
		/*
		* For clustersize > page size, just stay within
		* target page, otherwise we have to calculate pos
		* within the cluster and obey the rightmost
		* boundary.
		*/
		if (wc->w_large_pages) {
		/*
		* For cluster size < page size, we have to
		* calculate pos within the cluster and obey
		* the rightmost boundary.
		*/
		bytes = min(bytes, (unsigned long)(osb->s_clustersize
		- (wc->w_pos & (osb->s_clustersize - 1))));
		} else {
		/*
		* cluster size > page size is the most common
		* case - we just stay within the target page
		* boundary.
		*/
		bytes = min(bytes, PAGE_CACHE_SIZE - from);
		}

		to = from + bytes;

		if (wc->w_this_page_new)
		ret = ocfs2_map_page_blocks(wc->w_this_page, p_blkno, inode,
		cluster_start, cluster_end, 1);
		else
		ret = ocfs2_map_page_blocks(wc->w_this_page, p_blkno, inode,
		from, to, 0);
		if (ret) {
		mlog_errno(ret);
		goto out;
		}

		BUG_ON(from > PAGE_CACHE_SIZE);
		BUG_ON(to > PAGE_CACHE_SIZE);
		BUG_ON(from > osb->s_clustersize);
		BUG_ON(to > osb->s_clustersize);

		dst = kmap(wc->w_this_page);
		memcpy(dst + from, bp->b_src_buf + src_from, bytes);
		kunmap(wc->w_this_page);

		/*
		* XXX: This is slow, but simple. The caller of
		* ocfs2_buffered_write_cluster() is responsible for
		* passing through the iovecs, so it's difficult to
		* predict what our next step is in here after our
		* initial write. A future version should be pushing
		* that iovec manipulation further down.
		*
		* By setting this, we indicate that a copy from user
		* data was done, and subsequent calls for this
		* cluster will skip copying more data.
		*/
		wc->w_finished_copy = 1;

		*ret_from = from;
		*ret_to = to;
		out:

		return bytes ? (unsigned int)bytes : ret;
		}

		/*
		* Map, fill and write a page to disk.
		*
		* The work of copying data is done via callback. Newly allocated
		* pages which don't take user data will be zero'd (set 'new' to
		* indicate an allocating write)
		*
		* Returns a negative error code or the number of bytes copied into
		* the page.
		*/
		int ocfs2_write_data_page(struct inode inode, handle_t handle,
		u64 p_blkno, struct page page,
		struct ocfs2_write_ctxt *wc, int new)
		{
		int ret, copied = 0;
		unsigned int from = 0, to = 0;
		unsigned int cluster_start, cluster_end;
		unsigned int zero_from = 0, zero_to = 0;

		ocfs2_figure_cluster_boundaries(OCFS2_SB(inode->i_sb), wc->w_cpos,
		&cluster_start, &cluster_end);

		if ((wc->w_pos >> PAGE_CACHE_SHIFT) == page->index
		&& !wc->w_finished_copy) {

		wc->w_this_page = page;
		wc->w_this_page_new = new;
		ret = wc->w_write_data_page(inode, wc, p_blkno, &from, &to);
		if (ret < 0) {
		mlog_errno(ret);
		goto out;
		}

		copied = ret;

		zero_from = from;
		zero_to = to;
		if (new) {
		from = cluster_start;
		to = cluster_end;
		}
		} else {
		/*
		* If we haven't allocated the new page yet, we
		* shouldn't be writing it out without copying user
		* data. This is likely a math error from the caller.
		*/
		BUG_ON(!new);

		from = cluster_start;
		to = cluster_end;

		ret = ocfs2_map_page_blocks(page, p_blkno, inode,
		cluster_start, cluster_end, 1);
		if (ret) {
		mlog_errno(ret);
		goto out;
		}
		}

		/*
		* Parts of newly allocated pages need to be zero'd.
		*
		* Above, we have also rewritten 'to' and 'from' - as far as
		* the rest of the function is concerned, the entire cluster
		* range inside of a page needs to be written.
		*
		* We can skip this if the page is up to date - it's already
		* been zero'd from being read in as a hole.
		*/
		if (new && !PageUptodate(page))
		ocfs2_clear_page_regions(page, OCFS2_SB(inode->i_sb),
		wc->w_cpos, zero_from, zero_to);

		flush_dcache_page(page);

		if (ocfs2_should_order_data(inode)) {
		ret = walk_page_buffers(handle,
		page_buffers(page),
		from, to, NULL,
		ocfs2_journal_dirty_data);
		if (ret < 0)
		mlog_errno(ret);
		}

		/*
		* We don't use generic_commit_write() because we need to
		* handle our own i_size update.
		*/
		ret = block_commit_write(page, from, to);
		if (ret)
		mlog_errno(ret);
		out:

		return copied ? copied : ret;
		}

		/*
		* Do the actual write of some data into an inode. Optionally allocate
		* in order to fulfill the write.
		*
		* cpos is the logical cluster offset within the file to write at
		*
		* 'phys' is the physical mapping of that offset. a 'phys' value of
		* zero indicates that allocation is required. In this case, data_ac
		* and meta_ac should be valid (meta_ac can be null if metadata
		* allocation isn't required).
		*/
		static ssize_t ocfs2_write(struct file file, u32 phys, handle_t handle,
		struct buffer_head *di_bh,
		struct ocfs2_alloc_context *data_ac,
		struct ocfs2_alloc_context *meta_ac,
		struct ocfs2_write_ctxt *wc)
		{
		int ret, i, numpages = 1, new;
		unsigned int copied = 0;
		u32 tmp_pos;
		u64 v_blkno, p_blkno;
		struct address_space *mapping = file->f_mapping;
		struct inode *inode = mapping->host;
		unsigned int cbits = OCFS2_SB(inode->i_sb)->s_clustersize_bits;
		unsigned long index, start;
		struct page **cpages;

		new = phys == 0 ? 1 : 0;

		/*
		* Figure out how many pages we'll be manipulating here. For
		* non-allocating write, or any writes where cluster size is
		* less than page size, we only need one page. Otherwise,
		* allocating writes of cluster size larger than page size
		* need cluster size pages.
		*/
		if (new && !wc->w_large_pages)
		numpages = (1 << cbits) / PAGE_SIZE;

		cpages = kzalloc(sizeof(cpages) numpages, GFP_NOFS);
		if (!cpages) {
		ret = -ENOMEM;
		mlog_errno(ret);
		return ret;
		}

		/*
		* Fill our page array first. That way we've grabbed enough so
		* that we can zero and flush if we error after adding the
		* extent.
		*/
		if (new) {
		start = ocfs2_align_clusters_to_page_index(inode->i_sb,
		wc->w_cpos);
		v_blkno = ocfs2_clusters_to_blocks(inode->i_sb, wc->w_cpos);
		} else {
		start = wc->w_pos >> PAGE_CACHE_SHIFT;
		v_blkno = wc->w_pos >> inode->i_sb->s_blocksize_bits;
		}

		for(i = 0; i < numpages; i++) {
		index = start + i;

		cpages[i] = grab_cache_page(mapping, index);
		if (!cpages[i]) {
		ret = -ENOMEM;
		mlog_errno(ret);
		goto out;
		}
		}

		if (new) {
		/*
		* This is safe to call with the page locks - it won't take
		* any additional semaphores or cluster locks.
		*/
		tmp_pos = wc->w_cpos;
		ret = ocfs2_do_extend_allocation(OCFS2_SB(inode->i_sb), inode,
		&tmp_pos, 1, di_bh, handle,
		data_ac, meta_ac, NULL);
		/*
		* This shouldn't happen because we must have already
		* calculated the correct meta data allocation required. The
		* internal tree allocation code should know how to increase
		* transaction credits itself.
		*
		* If need be, we could handle -EAGAIN for a
		* RESTART_TRANS here.
		*/
		mlog_bug_on_msg(ret == -EAGAIN,
		"Inode %llu: EAGAIN return during allocation.\n",
		(unsigned long long)OCFS2_I(inode)->ip_blkno);
		if (ret < 0) {
		mlog_errno(ret);
		goto out;
		}
		}

		ret = ocfs2_extent_map_get_blocks(inode, v_blkno, &p_blkno, NULL);
		if (ret < 0) {

		/*
		* XXX: Should we go readonly here?
		*/

		mlog_errno(ret);
		goto out;
		}

		BUG_ON(p_blkno == 0);

		for(i = 0; i < numpages; i++) {
		ret = ocfs2_write_data_page(inode, handle, &p_blkno, cpages[i],
		wc, new);
		if (ret < 0) {
		mlog_errno(ret);
		goto out;
		}

		copied += ret;
		}

		out:
		for(i = 0; i < numpages; i++) {
		unlock_page(cpages[i]);
		mark_page_accessed(cpages[i]);
		page_cache_release(cpages[i]);
		}
		kfree(cpages);

		return copied ? copied : ret;
		}

		static void ocfs2_write_ctxt_init(struct ocfs2_write_ctxt *wc,
		struct ocfs2_super *osb, loff_t pos,
		size_t count, ocfs2_page_writer *cb,
		void *cb_priv)
		{
		wc->w_count = count;
		wc->w_pos = pos;
		wc->w_cpos = wc->w_pos >> osb->s_clustersize_bits;
		wc->w_finished_copy = 0;

		if (unlikely(PAGE_CACHE_SHIFT > osb->s_clustersize_bits))
		wc->w_large_pages = 1;
		else
		wc->w_large_pages = 0;

		wc->w_write_data_page = cb;
		wc->w_private = cb_priv;
		}

		/*
		* Write a cluster to an inode. The cluster may not be allocated yet,
		* in which case it will be. This only exists for buffered writes -
		* O_DIRECT takes a more "traditional" path through the kernel.
		*
		* The caller is responsible for incrementing pos, written counts, etc
		*
		* For file systems that don't support sparse files, pre-allocation
		* and page zeroing up until cpos should be done prior to this
		* function call.
		*
		* Callers should be holding i_sem, and the rw cluster lock.
		*
		* Returns the number of user bytes written, or less than zero for
		* error.
		*/
		ssize_t ocfs2_buffered_write_cluster(struct file *file, loff_t pos,
		size_t count, ocfs2_page_writer *actor,
		void *priv)
		{
		int ret, credits = OCFS2_INODE_UPDATE_CREDITS;
		ssize_t written = 0;
		u32 phys;
		struct inode *inode = file->f_mapping->host;
		struct ocfs2_super *osb = OCFS2_SB(inode->i_sb);
		struct buffer_head *di_bh = NULL;
		struct ocfs2_dinode *di;
		struct ocfs2_alloc_context *data_ac = NULL;
		struct ocfs2_alloc_context *meta_ac = NULL;
		handle_t *handle;
		struct ocfs2_write_ctxt wc;

		ocfs2_write_ctxt_init(&wc, osb, pos, count, actor, priv);

		ret = ocfs2_meta_lock(inode, &di_bh, 1);
		if (ret) {
		mlog_errno(ret);
		goto out;
		}
		di = (struct ocfs2_dinode *)di_bh->b_data;

		/*
		* Take alloc sem here to prevent concurrent lookups. That way
		* the mapping, zeroing and tree manipulation within
		* ocfs2_write() will be safe against ->readpage(). This
		* should also serve to lock out allocation from a shared
		* writeable region.
		*/
		down_write(&OCFS2_I(inode)->ip_alloc_sem);

		ret = ocfs2_get_clusters(inode, wc.w_cpos, &phys, NULL);
		if (ret) {
		mlog_errno(ret);
		goto out_meta;
		}

		/* phys == 0 means that allocation is required. */
		if (phys == 0) {
		ret = ocfs2_lock_allocators(inode, di, 1, &data_ac, &meta_ac);
		if (ret) {
		mlog_errno(ret);
		goto out_meta;
		}

		credits = ocfs2_calc_extend_credits(inode->i_sb, di, 1);
		}

		ret = ocfs2_data_lock(inode, 1);
		if (ret) {
		mlog_errno(ret);
		goto out_meta;
		}

		handle = ocfs2_start_trans(osb, credits);
		if (IS_ERR(handle)) {
		ret = PTR_ERR(handle);
		mlog_errno(ret);
		goto out_data;
		}

		written = ocfs2_write(file, phys, handle, di_bh, data_ac,
		meta_ac, &wc);
		if (written < 0) {
		ret = written;
		mlog_errno(ret);
		goto out_commit;
		}

		ret = ocfs2_journal_access(handle, inode, di_bh,
		OCFS2_JOURNAL_ACCESS_WRITE);
		if (ret) {
		mlog_errno(ret);
		goto out_commit;
		}

		pos += written;
		if (pos > inode->i_size) {
		i_size_write(inode, pos);
		mark_inode_dirty(inode);
		}
		inode->i_blocks = ocfs2_align_bytes_to_sectors((u64)(i_size_read(inode)));
		di->i_size = cpu_to_le64((u64)i_size_read(inode));
		inode->i_mtime = inode->i_ctime = CURRENT_TIME;
		di->i_mtime = di->i_ctime = cpu_to_le64(inode->i_mtime.tv_sec);
		di->i_mtime_nsec = di->i_ctime_nsec = cpu_to_le32(inode->i_mtime.tv_nsec);

		ret = ocfs2_journal_dirty(handle, di_bh);
		if (ret)
		mlog_errno(ret);

		out_commit:
		ocfs2_commit_trans(osb, handle);

		out_data:
		ocfs2_data_unlock(inode, 1);

		out_meta:
		up_write(&OCFS2_I(inode)->ip_alloc_sem);
		ocfs2_meta_unlock(inode, 1);

		out:
		brelse(di_bh);
		if (data_ac)
		ocfs2_free_alloc_context(data_ac);
		if (meta_ac)
		ocfs2_free_alloc_context(meta_ac);

		return written ? written : ret;
		}

		const struct address_space_operations ocfs2_aops = {
		.readpage = ocfs2_readpage,
		.writepage = ocfs2_writepage,

fs/ocfs2/aops.h

+38 −0

Original line number	Diff line number	Diff line
		@@ -30,6 +30,44 @@ handle_t ocfs2_start_walk_page_trans(struct inode inode,
		unsigned from,
		unsigned to);

		struct ocfs2_write_ctxt;
		typedef int (ocfs2_page_writer)(struct inode , struct ocfs2_write_ctxt ,
		u64 , unsigned int , unsigned int *);

		ssize_t ocfs2_buffered_write_cluster(struct file *file, loff_t pos,
		size_t count, ocfs2_page_writer *actor,
		void *priv);

		struct ocfs2_write_ctxt {
		size_t w_count;
		loff_t w_pos;
		u32 w_cpos;
		unsigned int w_finished_copy;

		/* This is true if page_size > cluster_size */
		unsigned int w_large_pages;

		/* Filler callback and private data */
		ocfs2_page_writer *w_write_data_page;
		void *w_private;

		/* Only valid for the filler callback */
		struct page *w_this_page;
		unsigned int w_this_page_new;
		};

		struct ocfs2_buffered_write_priv {
		char *b_src_buf;
		const struct iovec b_cur_iov; / Current iovec */
		size_t b_cur_off; /* Offset in the
		* current iovec */
		};
		int ocfs2_map_and_write_user_data(struct inode *inode,
		struct ocfs2_write_ctxt *wc,
		u64 *p_blkno,
		unsigned int *ret_from,
		unsigned int *ret_to);

		/* all ocfs2_dio_end_io()'s fault */
		#define ocfs2_iocb_is_rw_locked(iocb) \
		test_bit(0, (unsigned long *)&iocb->private)

fs/ocfs2/extent_map.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -67,7 +67,7 @@ static int ocfs2_search_extent_list(struct ocfs2_extent_list *el,
		return ret;
		}

		static int ocfs2_get_clusters(struct inode *inode, u32 v_cluster,
		int ocfs2_get_clusters(struct inode *inode, u32 v_cluster,
		u32 p_cluster, u32 num_clusters)
		{
		int ret, i;

fs/ocfs2/extent_map.h

+2 −0

Original line number	Diff line number	Diff line
		@@ -25,6 +25,8 @@
		#ifndef _EXTENT_MAP_H
		#define _EXTENT_MAP_H

		int ocfs2_get_clusters(struct inode inode, u32 v_cluster, u32 p_cluster,
		u32 *num_clusters);
		int ocfs2_extent_map_get_blocks(struct inode inode, u64 v_blkno, u64 p_blkno,
		int *ret_count);

fs/ocfs2/file.c

+335 −39

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