addr.c 32.1 KB
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#include "ceph_debug.h"

#include <linux/backing-dev.h>
#include <linux/fs.h>
#include <linux/mm.h>
#include <linux/pagemap.h>
#include <linux/writeback.h>	/* generic_writepages */
#include <linux/pagevec.h>
#include <linux/task_io_accounting_ops.h>

#include "super.h"
#include "osd_client.h"

/*
 * Ceph address space ops.
 *
 * There are a few funny things going on here.
 *
 * The page->private field is used to reference a struct
 * ceph_snap_context for _every_ dirty page.  This indicates which
 * snapshot the page was logically dirtied in, and thus which snap
 * context needs to be associated with the osd write during writeback.
 *
 * Similarly, struct ceph_inode_info maintains a set of counters to
 * count dirty pages on the inode.  In the absense of snapshots,
 * i_wrbuffer_ref == i_wrbuffer_ref_head == the dirty page count.
 *
 * When a snapshot is taken (that is, when the client receives
 * notification that a snapshot was taken), each inode with caps and
 * with dirty pages (dirty pages implies there is a cap) gets a new
 * ceph_cap_snap in the i_cap_snaps list (which is sorted in ascending
 * order, new snaps go to the tail).  The i_wrbuffer_ref_head count is
 * moved to capsnap->dirty. (Unless a sync write is currently in
 * progress.  In that case, the capsnap is said to be "pending", new
 * writes cannot start, and the capsnap isn't "finalized" until the
 * write completes (or fails) and a final size/mtime for the inode for
 * that snap can be settled upon.)  i_wrbuffer_ref_head is reset to 0.
 *
 * On writeback, we must submit writes to the osd IN SNAP ORDER.  So,
 * we look for the first capsnap in i_cap_snaps and write out pages in
 * that snap context _only_.  Then we move on to the next capsnap,
 * eventually reaching the "live" or "head" context (i.e., pages that
 * are not yet snapped) and are writing the most recently dirtied
 * pages.
 *
 * Invalidate and so forth must take care to ensure the dirty page
 * accounting is preserved.
 */

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#define CONGESTION_ON_THRESH(congestion_kb) (congestion_kb >> (PAGE_SHIFT-10))
#define CONGESTION_OFF_THRESH(congestion_kb)				\
	(CONGESTION_ON_THRESH(congestion_kb) -				\
	 (CONGESTION_ON_THRESH(congestion_kb) >> 2))


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/*
 * Dirty a page.  Optimistically adjust accounting, on the assumption
 * that we won't race with invalidate.  If we do, readjust.
 */
static int ceph_set_page_dirty(struct page *page)
{
	struct address_space *mapping = page->mapping;
	struct inode *inode;
	struct ceph_inode_info *ci;
	int undo = 0;
	struct ceph_snap_context *snapc;

	if (unlikely(!mapping))
		return !TestSetPageDirty(page);

	if (TestSetPageDirty(page)) {
		dout("%p set_page_dirty %p idx %lu -- already dirty\n",
		     mapping->host, page, page->index);
		return 0;
	}

	inode = mapping->host;
	ci = ceph_inode(inode);

	/*
	 * Note that we're grabbing a snapc ref here without holding
	 * any locks!
	 */
	snapc = ceph_get_snap_context(ci->i_snap_realm->cached_context);

	/* dirty the head */
	spin_lock(&inode->i_lock);
	if (ci->i_wrbuffer_ref_head == 0)
		ci->i_head_snapc = ceph_get_snap_context(snapc);
	++ci->i_wrbuffer_ref_head;
	if (ci->i_wrbuffer_ref == 0)
		igrab(inode);
	++ci->i_wrbuffer_ref;
	dout("%p set_page_dirty %p idx %lu head %d/%d -> %d/%d "
	     "snapc %p seq %lld (%d snaps)\n",
	     mapping->host, page, page->index,
	     ci->i_wrbuffer_ref-1, ci->i_wrbuffer_ref_head-1,
	     ci->i_wrbuffer_ref, ci->i_wrbuffer_ref_head,
	     snapc, snapc->seq, snapc->num_snaps);
	spin_unlock(&inode->i_lock);

	/* now adjust page */
	spin_lock_irq(&mapping->tree_lock);
	if (page->mapping) {	/* Race with truncate? */
		WARN_ON_ONCE(!PageUptodate(page));

		if (mapping_cap_account_dirty(mapping)) {
			__inc_zone_page_state(page, NR_FILE_DIRTY);
			__inc_bdi_stat(mapping->backing_dev_info,
					BDI_RECLAIMABLE);
			task_io_account_write(PAGE_CACHE_SIZE);
		}
		radix_tree_tag_set(&mapping->page_tree,
				page_index(page), PAGECACHE_TAG_DIRTY);

		/*
		 * Reference snap context in page->private.  Also set
		 * PagePrivate so that we get invalidatepage callback.
		 */
		page->private = (unsigned long)snapc;
		SetPagePrivate(page);
	} else {
		dout("ANON set_page_dirty %p (raced truncate?)\n", page);
		undo = 1;
	}

	spin_unlock_irq(&mapping->tree_lock);

	if (undo)
		/* whoops, we failed to dirty the page */
		ceph_put_wrbuffer_cap_refs(ci, 1, snapc);

	__mark_inode_dirty(mapping->host, I_DIRTY_PAGES);

	BUG_ON(!PageDirty(page));
	return 1;
}

/*
 * If we are truncating the full page (i.e. offset == 0), adjust the
 * dirty page counters appropriately.  Only called if there is private
 * data on the page.
 */
static void ceph_invalidatepage(struct page *page, unsigned long offset)
{
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	struct inode *inode;
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	struct ceph_inode_info *ci;
	struct ceph_snap_context *snapc = (void *)page->private;

	BUG_ON(!PageLocked(page));
	BUG_ON(!page->private);
	BUG_ON(!PagePrivate(page));
	BUG_ON(!page->mapping);

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	inode = page->mapping->host;

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	/*
	 * We can get non-dirty pages here due to races between
	 * set_page_dirty and truncate_complete_page; just spit out a
	 * warning, in case we end up with accounting problems later.
	 */
	if (!PageDirty(page))
		pr_err("%p invalidatepage %p page not dirty\n", inode, page);

	if (offset == 0)
		ClearPageChecked(page);

	ci = ceph_inode(inode);
	if (offset == 0) {
		dout("%p invalidatepage %p idx %lu full dirty page %lu\n",
		     inode, page, page->index, offset);
		ceph_put_wrbuffer_cap_refs(ci, 1, snapc);
		ceph_put_snap_context(snapc);
		page->private = 0;
		ClearPagePrivate(page);
	} else {
		dout("%p invalidatepage %p idx %lu partial dirty page\n",
		     inode, page, page->index);
	}
}

/* just a sanity check */
static int ceph_releasepage(struct page *page, gfp_t g)
{
	struct inode *inode = page->mapping ? page->mapping->host : NULL;
	dout("%p releasepage %p idx %lu\n", inode, page, page->index);
	WARN_ON(PageDirty(page));
	WARN_ON(page->private);
	WARN_ON(PagePrivate(page));
	return 0;
}

/*
 * read a single page, without unlocking it.
 */
static int readpage_nounlock(struct file *filp, struct page *page)
{
	struct inode *inode = filp->f_dentry->d_inode;
	struct ceph_inode_info *ci = ceph_inode(inode);
	struct ceph_osd_client *osdc = &ceph_inode_to_client(inode)->osdc;
	int err = 0;
	u64 len = PAGE_CACHE_SIZE;

	dout("readpage inode %p file %p page %p index %lu\n",
	     inode, filp, page, page->index);
	err = ceph_osdc_readpages(osdc, ceph_vino(inode), &ci->i_layout,
				  page->index << PAGE_CACHE_SHIFT, &len,
				  ci->i_truncate_seq, ci->i_truncate_size,
				  &page, 1);
	if (err == -ENOENT)
		err = 0;
	if (err < 0) {
		SetPageError(page);
		goto out;
	} else if (err < PAGE_CACHE_SIZE) {
		/* zero fill remainder of page */
		zero_user_segment(page, err, PAGE_CACHE_SIZE);
	}
	SetPageUptodate(page);

out:
	return err < 0 ? err : 0;
}

static int ceph_readpage(struct file *filp, struct page *page)
{
	int r = readpage_nounlock(filp, page);
	unlock_page(page);
	return r;
}

/*
 * Build a vector of contiguous pages from the provided page list.
 */
static struct page **page_vector_from_list(struct list_head *page_list,
					   unsigned *nr_pages)
{
	struct page **pages;
	struct page *page;
	int next_index, contig_pages = 0;

	/* build page vector */
	pages = kmalloc(sizeof(*pages) * *nr_pages, GFP_NOFS);
	if (!pages)
		return ERR_PTR(-ENOMEM);

	BUG_ON(list_empty(page_list));
	next_index = list_entry(page_list->prev, struct page, lru)->index;
	list_for_each_entry_reverse(page, page_list, lru) {
		if (page->index == next_index) {
			dout("readpages page %d %p\n", contig_pages, page);
			pages[contig_pages] = page;
			contig_pages++;
			next_index++;
		} else {
			break;
		}
	}
	*nr_pages = contig_pages;
	return pages;
}

/*
 * Read multiple pages.  Leave pages we don't read + unlock in page_list;
 * the caller (VM) cleans them up.
 */
static int ceph_readpages(struct file *file, struct address_space *mapping,
			  struct list_head *page_list, unsigned nr_pages)
{
	struct inode *inode = file->f_dentry->d_inode;
	struct ceph_inode_info *ci = ceph_inode(inode);
	struct ceph_osd_client *osdc = &ceph_inode_to_client(inode)->osdc;
	int rc = 0;
	struct page **pages;
	struct pagevec pvec;
	loff_t offset;
	u64 len;

	dout("readpages %p file %p nr_pages %d\n",
	     inode, file, nr_pages);

	pages = page_vector_from_list(page_list, &nr_pages);
	if (IS_ERR(pages))
		return PTR_ERR(pages);

	/* guess read extent */
	offset = pages[0]->index << PAGE_CACHE_SHIFT;
	len = nr_pages << PAGE_CACHE_SHIFT;
	rc = ceph_osdc_readpages(osdc, ceph_vino(inode), &ci->i_layout,
				 offset, &len,
				 ci->i_truncate_seq, ci->i_truncate_size,
				 pages, nr_pages);
	if (rc == -ENOENT)
		rc = 0;
	if (rc < 0)
		goto out;

	/* set uptodate and add to lru in pagevec-sized chunks */
	pagevec_init(&pvec, 0);
	for (; !list_empty(page_list) && len > 0;
	     rc -= PAGE_CACHE_SIZE, len -= PAGE_CACHE_SIZE) {
		struct page *page =
			list_entry(page_list->prev, struct page, lru);

		list_del(&page->lru);

		if (rc < (int)PAGE_CACHE_SIZE) {
			/* zero (remainder of) page */
			int s = rc < 0 ? 0 : rc;
			zero_user_segment(page, s, PAGE_CACHE_SIZE);
		}

		if (add_to_page_cache(page, mapping, page->index, GFP_NOFS)) {
			page_cache_release(page);
			dout("readpages %p add_to_page_cache failed %p\n",
			     inode, page);
			continue;
		}
		dout("readpages %p adding %p idx %lu\n", inode, page,
		     page->index);
		flush_dcache_page(page);
		SetPageUptodate(page);
		unlock_page(page);
		if (pagevec_add(&pvec, page) == 0)
			pagevec_lru_add_file(&pvec);   /* add to lru */
	}
	pagevec_lru_add_file(&pvec);
	rc = 0;

out:
	kfree(pages);
	return rc;
}

/*
 * Get ref for the oldest snapc for an inode with dirty data... that is, the
 * only snap context we are allowed to write back.
 *
 * Caller holds i_lock.
 */
static struct ceph_snap_context *__get_oldest_context(struct inode *inode,
						      u64 *snap_size)
{
	struct ceph_inode_info *ci = ceph_inode(inode);
	struct ceph_snap_context *snapc = NULL;
	struct ceph_cap_snap *capsnap = NULL;

	list_for_each_entry(capsnap, &ci->i_cap_snaps, ci_item) {
		dout(" cap_snap %p snapc %p has %d dirty pages\n", capsnap,
		     capsnap->context, capsnap->dirty_pages);
		if (capsnap->dirty_pages) {
			snapc = ceph_get_snap_context(capsnap->context);
			if (snap_size)
				*snap_size = capsnap->size;
			break;
		}
	}
	if (!snapc && ci->i_snap_realm) {
		snapc = ceph_get_snap_context(ci->i_snap_realm->cached_context);
		dout(" head snapc %p has %d dirty pages\n",
		     snapc, ci->i_wrbuffer_ref_head);
	}
	return snapc;
}

static struct ceph_snap_context *get_oldest_context(struct inode *inode,
						    u64 *snap_size)
{
	struct ceph_snap_context *snapc = NULL;

	spin_lock(&inode->i_lock);
	snapc = __get_oldest_context(inode, snap_size);
	spin_unlock(&inode->i_lock);
	return snapc;
}

/*
 * Write a single page, but leave the page locked.
 *
 * If we get a write error, set the page error bit, but still adjust the
 * dirty page accounting (i.e., page is no longer dirty).
 */
static int writepage_nounlock(struct page *page, struct writeback_control *wbc)
{
	struct inode *inode;
	struct ceph_inode_info *ci;
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	struct ceph_client *client;
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	struct ceph_osd_client *osdc;
	loff_t page_off = page->index << PAGE_CACHE_SHIFT;
	int len = PAGE_CACHE_SIZE;
	loff_t i_size;
	int err = 0;
	struct ceph_snap_context *snapc;
	u64 snap_size = 0;
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	long writeback_stat;
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	dout("writepage %p idx %lu\n", page, page->index);

	if (!page->mapping || !page->mapping->host) {
		dout("writepage %p - no mapping\n", page);
		return -EFAULT;
	}
	inode = page->mapping->host;
	ci = ceph_inode(inode);
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	client = ceph_inode_to_client(inode);
	osdc = &client->osdc;
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	/* verify this is a writeable snap context */
	snapc = (void *)page->private;
	if (snapc == NULL) {
		dout("writepage %p page %p not dirty?\n", inode, page);
		goto out;
	}
	if (snapc != get_oldest_context(inode, &snap_size)) {
		dout("writepage %p page %p snapc %p not writeable - noop\n",
		     inode, page, (void *)page->private);
		/* we should only noop if called by kswapd */
		WARN_ON((current->flags & PF_MEMALLOC) == 0);
		goto out;
	}

	/* is this a partial page at end of file? */
	if (snap_size)
		i_size = snap_size;
	else
		i_size = i_size_read(inode);
	if (i_size < page_off + len)
		len = i_size - page_off;

	dout("writepage %p page %p index %lu on %llu~%u\n",
	     inode, page, page->index, page_off, len);

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	writeback_stat = atomic_long_inc_return(&client->writeback_count);
	if (writeback_stat >
	    CONGESTION_ON_THRESH(client->mount_args->congestion_kb))
		set_bdi_congested(&client->backing_dev_info, BLK_RW_ASYNC);

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	set_page_writeback(page);
	err = ceph_osdc_writepages(osdc, ceph_vino(inode),
				   &ci->i_layout, snapc,
				   page_off, len,
				   ci->i_truncate_seq, ci->i_truncate_size,
				   &inode->i_mtime,
				   &page, 1, 0, 0, true);
	if (err < 0) {
		dout("writepage setting page/mapping error %d %p\n", err, page);
		SetPageError(page);
		mapping_set_error(&inode->i_data, err);
		if (wbc)
			wbc->pages_skipped++;
	} else {
		dout("writepage cleaned page %p\n", page);
		err = 0;  /* vfs expects us to return 0 */
	}
	page->private = 0;
	ClearPagePrivate(page);
	end_page_writeback(page);
	ceph_put_wrbuffer_cap_refs(ci, 1, snapc);
	ceph_put_snap_context(snapc);
out:
	return err;
}

static int ceph_writepage(struct page *page, struct writeback_control *wbc)
{
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	int err;
	struct inode *inode = page->mapping->host;
	BUG_ON(!inode);
	igrab(inode);
	err = writepage_nounlock(page, wbc);
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	unlock_page(page);
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	iput(inode);
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	return err;
}


/*
 * lame release_pages helper.  release_pages() isn't exported to
 * modules.
 */
static void ceph_release_pages(struct page **pages, int num)
{
	struct pagevec pvec;
	int i;

	pagevec_init(&pvec, 0);
	for (i = 0; i < num; i++) {
		if (pagevec_add(&pvec, pages[i]) == 0)
			pagevec_release(&pvec);
	}
	pagevec_release(&pvec);
}


/*
 * async writeback completion handler.
 *
 * If we get an error, set the mapping error bit, but not the individual
 * page error bits.
 */
static void writepages_finish(struct ceph_osd_request *req,
			      struct ceph_msg *msg)
{
	struct inode *inode = req->r_inode;
	struct ceph_osd_reply_head *replyhead;
	struct ceph_osd_op *op;
	struct ceph_inode_info *ci = ceph_inode(inode);
	unsigned wrote;
	struct page *page;
	int i;
	struct ceph_snap_context *snapc = req->r_snapc;
	struct address_space *mapping = inode->i_mapping;
	struct writeback_control *wbc = req->r_wbc;
	__s32 rc = -EIO;
	u64 bytes = 0;
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	struct ceph_client *client = ceph_inode_to_client(inode);
	long writeback_stat;
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	unsigned issued = __ceph_caps_issued(ci, NULL);
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	/* parse reply */
	replyhead = msg->front.iov_base;
	WARN_ON(le32_to_cpu(replyhead->num_ops) == 0);
	op = (void *)(replyhead + 1);
	rc = le32_to_cpu(replyhead->result);
	bytes = le64_to_cpu(op->extent.length);

	if (rc >= 0) {
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		/*
		 * Assume we wrote the pages we originally sent.  The
		 * osd might reply with fewer pages if our writeback
		 * raced with a truncation and was adjusted at the osd,
		 * so don't believe the reply.
		 */
		wrote = req->r_num_pages;
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	} else {
		wrote = 0;
		mapping_set_error(mapping, rc);
	}
	dout("writepages_finish %p rc %d bytes %llu wrote %d (pages)\n",
	     inode, rc, bytes, wrote);

	/* clean all pages */
	for (i = 0; i < req->r_num_pages; i++) {
		page = req->r_pages[i];
		BUG_ON(!page);
		WARN_ON(!PageUptodate(page));

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		writeback_stat =
			atomic_long_dec_return(&client->writeback_count);
		if (writeback_stat <
		    CONGESTION_OFF_THRESH(client->mount_args->congestion_kb))
			clear_bdi_congested(&client->backing_dev_info,
					    BLK_RW_ASYNC);

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		if (i >= wrote) {
			dout("inode %p skipping page %p\n", inode, page);
			wbc->pages_skipped++;
		}
		page->private = 0;
		ClearPagePrivate(page);
		ceph_put_snap_context(snapc);
		dout("unlocking %d %p\n", i, page);
		end_page_writeback(page);
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		/*
		 * We lost the cache cap, need to truncate the page before
		 * it is unlocked, otherwise we'd truncate it later in the
		 * page truncation thread, possibly losing some data that
		 * raced its way in
		 */
		if ((issued & CEPH_CAP_FILE_CACHE) == 0)
			generic_error_remove_page(inode->i_mapping, page);

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		unlock_page(page);
	}
	dout("%p wrote+cleaned %d pages\n", inode, wrote);
	ceph_put_wrbuffer_cap_refs(ci, req->r_num_pages, snapc);

	ceph_release_pages(req->r_pages, req->r_num_pages);
	if (req->r_pages_from_pool)
		mempool_free(req->r_pages,
			     ceph_client(inode->i_sb)->wb_pagevec_pool);
	else
		kfree(req->r_pages);
	ceph_osdc_put_request(req);
}

/*
 * allocate a page vec, either directly, or if necessary, via a the
 * mempool.  we avoid the mempool if we can because req->r_num_pages
 * may be less than the maximum write size.
 */
static void alloc_page_vec(struct ceph_client *client,
			   struct ceph_osd_request *req)
{
	req->r_pages = kmalloc(sizeof(struct page *) * req->r_num_pages,
			       GFP_NOFS);
	if (!req->r_pages) {
		req->r_pages = mempool_alloc(client->wb_pagevec_pool, GFP_NOFS);
		req->r_pages_from_pool = 1;
		WARN_ON(!req->r_pages);
	}
}

/*
 * initiate async writeback
 */
static int ceph_writepages_start(struct address_space *mapping,
				 struct writeback_control *wbc)
{
	struct inode *inode = mapping->host;
	struct backing_dev_info *bdi = mapping->backing_dev_info;
	struct ceph_inode_info *ci = ceph_inode(inode);
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	struct ceph_client *client;
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616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646
	pgoff_t index, start, end;
	int range_whole = 0;
	int should_loop = 1;
	pgoff_t max_pages = 0, max_pages_ever = 0;
	struct ceph_snap_context *snapc = NULL, *last_snapc = NULL;
	struct pagevec pvec;
	int done = 0;
	int rc = 0;
	unsigned wsize = 1 << inode->i_blkbits;
	struct ceph_osd_request *req = NULL;
	int do_sync;
	u64 snap_size = 0;

	/*
	 * Include a 'sync' in the OSD request if this is a data
	 * integrity write (e.g., O_SYNC write or fsync()), or if our
	 * cap is being revoked.
	 */
	do_sync = wbc->sync_mode == WB_SYNC_ALL;
	if (ceph_caps_revoking(ci, CEPH_CAP_FILE_BUFFER))
		do_sync = 1;
	dout("writepages_start %p dosync=%d (mode=%s)\n",
	     inode, do_sync,
	     wbc->sync_mode == WB_SYNC_NONE ? "NONE" :
	     (wbc->sync_mode == WB_SYNC_ALL ? "ALL" : "HOLD"));

	client = ceph_inode_to_client(inode);
	if (client->mount_state == CEPH_MOUNT_SHUTDOWN) {
		pr_warning("writepage_start %p on forced umount\n", inode);
		return -EIO; /* we're in a forced umount, don't write! */
	}
647 648
	if (client->mount_args->wsize && client->mount_args->wsize < wsize)
		wsize = client->mount_args->wsize;
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Sage Weil 已提交
649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707
	if (wsize < PAGE_CACHE_SIZE)
		wsize = PAGE_CACHE_SIZE;
	max_pages_ever = wsize >> PAGE_CACHE_SHIFT;

	pagevec_init(&pvec, 0);

	/* ?? */
	if (wbc->nonblocking && bdi_write_congested(bdi)) {
		dout(" writepages congested\n");
		wbc->encountered_congestion = 1;
		goto out_final;
	}

	/* where to start/end? */
	if (wbc->range_cyclic) {
		start = mapping->writeback_index; /* Start from prev offset */
		end = -1;
		dout(" cyclic, start at %lu\n", start);
	} else {
		start = wbc->range_start >> PAGE_CACHE_SHIFT;
		end = wbc->range_end >> PAGE_CACHE_SHIFT;
		if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX)
			range_whole = 1;
		should_loop = 0;
		dout(" not cyclic, %lu to %lu\n", start, end);
	}
	index = start;

retry:
	/* find oldest snap context with dirty data */
	ceph_put_snap_context(snapc);
	snapc = get_oldest_context(inode, &snap_size);
	if (!snapc) {
		/* hmm, why does writepages get called when there
		   is no dirty data? */
		dout(" no snap context with dirty data?\n");
		goto out;
	}
	dout(" oldest snapc is %p seq %lld (%d snaps)\n",
	     snapc, snapc->seq, snapc->num_snaps);
	if (last_snapc && snapc != last_snapc) {
		/* if we switched to a newer snapc, restart our scan at the
		 * start of the original file range. */
		dout("  snapc differs from last pass, restarting at %lu\n",
		     index);
		index = start;
	}
	last_snapc = snapc;

	while (!done && index <= end) {
		unsigned i;
		int first;
		pgoff_t next;
		int pvec_pages, locked_pages;
		struct page *page;
		int want;
		u64 offset, len;
		struct ceph_osd_request_head *reqhead;
		struct ceph_osd_op *op;
Y
Yehuda Sadeh 已提交
708
		long writeback_stat;
S
Sage Weil 已提交
709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815

		next = 0;
		locked_pages = 0;
		max_pages = max_pages_ever;

get_more_pages:
		first = -1;
		want = min(end - index,
			   min((pgoff_t)PAGEVEC_SIZE,
			       max_pages - (pgoff_t)locked_pages) - 1)
			+ 1;
		pvec_pages = pagevec_lookup_tag(&pvec, mapping, &index,
						PAGECACHE_TAG_DIRTY,
						want);
		dout("pagevec_lookup_tag got %d\n", pvec_pages);
		if (!pvec_pages && !locked_pages)
			break;
		for (i = 0; i < pvec_pages && locked_pages < max_pages; i++) {
			page = pvec.pages[i];
			dout("? %p idx %lu\n", page, page->index);
			if (locked_pages == 0)
				lock_page(page);  /* first page */
			else if (!trylock_page(page))
				break;

			/* only dirty pages, or our accounting breaks */
			if (unlikely(!PageDirty(page)) ||
			    unlikely(page->mapping != mapping)) {
				dout("!dirty or !mapping %p\n", page);
				unlock_page(page);
				break;
			}
			if (!wbc->range_cyclic && page->index > end) {
				dout("end of range %p\n", page);
				done = 1;
				unlock_page(page);
				break;
			}
			if (next && (page->index != next)) {
				dout("not consecutive %p\n", page);
				unlock_page(page);
				break;
			}
			if (wbc->sync_mode != WB_SYNC_NONE) {
				dout("waiting on writeback %p\n", page);
				wait_on_page_writeback(page);
			}
			if ((snap_size && page_offset(page) > snap_size) ||
			    (!snap_size &&
			     page_offset(page) > i_size_read(inode))) {
				dout("%p page eof %llu\n", page, snap_size ?
				     snap_size : i_size_read(inode));
				done = 1;
				unlock_page(page);
				break;
			}
			if (PageWriteback(page)) {
				dout("%p under writeback\n", page);
				unlock_page(page);
				break;
			}

			/* only if matching snap context */
			if (snapc != (void *)page->private) {
				dout("page snapc %p != oldest %p\n",
				     (void *)page->private, snapc);
				unlock_page(page);
				if (!locked_pages)
					continue; /* keep looking for snap */
				break;
			}

			if (!clear_page_dirty_for_io(page)) {
				dout("%p !clear_page_dirty_for_io\n", page);
				unlock_page(page);
				break;
			}

			/* ok */
			if (locked_pages == 0) {
				/* prepare async write request */
				offset = page->index << PAGE_CACHE_SHIFT;
				len = wsize;
				req = ceph_osdc_new_request(&client->osdc,
					    &ci->i_layout,
					    ceph_vino(inode),
					    offset, &len,
					    CEPH_OSD_OP_WRITE,
					    CEPH_OSD_FLAG_WRITE |
						    CEPH_OSD_FLAG_ONDISK,
					    snapc, do_sync,
					    ci->i_truncate_seq,
					    ci->i_truncate_size,
					    &inode->i_mtime, true, 1);
				max_pages = req->r_num_pages;

				alloc_page_vec(client, req);
				req->r_callback = writepages_finish;
				req->r_inode = inode;
				req->r_wbc = wbc;
			}

			/* note position of first page in pvec */
			if (first < 0)
				first = i;
			dout("%p will write page %p idx %lu\n",
			     inode, page, page->index);
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Yehuda Sadeh 已提交
816 817 818 819 820 821

			writeback_stat = atomic_long_inc_return(&client->writeback_count);
			if (writeback_stat > CONGESTION_ON_THRESH(client->mount_args->congestion_kb)) {
				set_bdi_congested(&client->backing_dev_info, BLK_RW_ASYNC);
			}

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Sage Weil 已提交
822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921
			set_page_writeback(page);
			req->r_pages[locked_pages] = page;
			locked_pages++;
			next = page->index + 1;
		}

		/* did we get anything? */
		if (!locked_pages)
			goto release_pvec_pages;
		if (i) {
			int j;
			BUG_ON(!locked_pages || first < 0);

			if (pvec_pages && i == pvec_pages &&
			    locked_pages < max_pages) {
				dout("reached end pvec, trying for more\n");
				pagevec_reinit(&pvec);
				goto get_more_pages;
			}

			/* shift unused pages over in the pvec...  we
			 * will need to release them below. */
			for (j = i; j < pvec_pages; j++) {
				dout(" pvec leftover page %p\n",
				     pvec.pages[j]);
				pvec.pages[j-i+first] = pvec.pages[j];
			}
			pvec.nr -= i-first;
		}

		/* submit the write */
		offset = req->r_pages[0]->index << PAGE_CACHE_SHIFT;
		len = min((snap_size ? snap_size : i_size_read(inode)) - offset,
			  (u64)locked_pages << PAGE_CACHE_SHIFT);
		dout("writepages got %d pages at %llu~%llu\n",
		     locked_pages, offset, len);

		/* revise final length, page count */
		req->r_num_pages = locked_pages;
		reqhead = req->r_request->front.iov_base;
		op = (void *)(reqhead + 1);
		op->extent.length = cpu_to_le64(len);
		op->payload_len = cpu_to_le32(len);
		req->r_request->hdr.data_len = cpu_to_le32(len);

		ceph_osdc_start_request(&client->osdc, req, true);
		req = NULL;

		/* continue? */
		index = next;
		wbc->nr_to_write -= locked_pages;
		if (wbc->nr_to_write <= 0)
			done = 1;

release_pvec_pages:
		dout("pagevec_release on %d pages (%p)\n", (int)pvec.nr,
		     pvec.nr ? pvec.pages[0] : NULL);
		pagevec_release(&pvec);

		if (locked_pages && !done)
			goto retry;
	}

	if (should_loop && !done) {
		/* more to do; loop back to beginning of file */
		dout("writepages looping back to beginning of file\n");
		should_loop = 0;
		index = 0;
		goto retry;
	}

	if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0))
		mapping->writeback_index = index;

out:
	if (req)
		ceph_osdc_put_request(req);
	if (rc > 0)
		rc = 0;  /* vfs expects us to return 0 */
	ceph_put_snap_context(snapc);
	dout("writepages done, rc = %d\n", rc);
out_final:
	return rc;
}



/*
 * See if a given @snapc is either writeable, or already written.
 */
static int context_is_writeable_or_written(struct inode *inode,
					   struct ceph_snap_context *snapc)
{
	struct ceph_snap_context *oldest = get_oldest_context(inode, NULL);
	return !oldest || snapc->seq <= oldest->seq;
}

/*
 * We are only allowed to write into/dirty the page if the page is
 * clean, or already dirty within the same snap context.
922 923 924 925
 *
 * called with page locked.
 * return success with page locked,
 * or any failure (incl -EAGAIN) with page unlocked.
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Sage Weil 已提交
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 */
927 928 929
static int ceph_update_writeable_page(struct file *file,
			    loff_t pos, unsigned len,
			    struct page *page)
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{
	struct inode *inode = file->f_dentry->d_inode;
	struct ceph_inode_info *ci = ceph_inode(inode);
	struct ceph_mds_client *mdsc = &ceph_inode_to_client(inode)->mdsc;
	loff_t page_off = pos & PAGE_CACHE_MASK;
	int pos_in_page = pos & ~PAGE_CACHE_MASK;
	int end_in_page = pos_in_page + len;
	loff_t i_size;
	struct ceph_snap_context *snapc;
	int r;

retry_locked:
	/* writepages currently holds page lock, but if we change that later, */
	wait_on_page_writeback(page);

	/* check snap context */
	BUG_ON(!ci->i_snap_realm);
	down_read(&mdsc->snap_rwsem);
	BUG_ON(!ci->i_snap_realm->cached_context);
	if (page->private &&
	    (void *)page->private != ci->i_snap_realm->cached_context) {
		/*
		 * this page is already dirty in another (older) snap
		 * context!  is it writeable now?
		 */
		snapc = get_oldest_context(inode, NULL);
		up_read(&mdsc->snap_rwsem);

		if (snapc != (void *)page->private) {
			dout(" page %p snapc %p not current or oldest\n",
			     page, (void *)page->private);
			/*
			 * queue for writeback, and wait for snapc to
			 * be writeable or written
			 */
			snapc = ceph_get_snap_context((void *)page->private);
			unlock_page(page);
967
			ceph_queue_writeback(inode);
968
			r = wait_event_interruptible(ci->i_cap_wq,
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Sage Weil 已提交
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			       context_is_writeable_or_written(inode, snapc));
			ceph_put_snap_context(snapc);
971 972
			if (r == -ERESTARTSYS)
				return r;
973
			return -EAGAIN;
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		}

		/* yay, writeable, do it now (without dropping page lock) */
		dout(" page %p snapc %p not current, but oldest\n",
		     page, snapc);
		if (!clear_page_dirty_for_io(page))
			goto retry_locked;
		r = writepage_nounlock(page, NULL);
		if (r < 0)
			goto fail_nosnap;
		goto retry_locked;
	}

	if (PageUptodate(page)) {
		dout(" page %p already uptodate\n", page);
		return 0;
	}

	/* full page? */
	if (pos_in_page == 0 && len == PAGE_CACHE_SIZE)
		return 0;

	/* past end of file? */
	i_size = inode->i_size;   /* caller holds i_mutex */

	if (i_size + len > inode->i_sb->s_maxbytes) {
		/* file is too big */
		r = -EINVAL;
		goto fail;
	}

	if (page_off >= i_size ||
	    (pos_in_page == 0 && (pos+len) >= i_size &&
	     end_in_page - pos_in_page != PAGE_CACHE_SIZE)) {
		dout(" zeroing %p 0 - %d and %d - %d\n",
		     page, pos_in_page, end_in_page, (int)PAGE_CACHE_SIZE);
		zero_user_segments(page,
				   0, pos_in_page,
				   end_in_page, PAGE_CACHE_SIZE);
		return 0;
	}

	/* we need to read it. */
	up_read(&mdsc->snap_rwsem);
	r = readpage_nounlock(file, page);
	if (r < 0)
		goto fail_nosnap;
	goto retry_locked;

fail:
	up_read(&mdsc->snap_rwsem);
fail_nosnap:
	unlock_page(page);
	return r;
}

1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043
/*
 * We are only allowed to write into/dirty the page if the page is
 * clean, or already dirty within the same snap context.
 */
static int ceph_write_begin(struct file *file, struct address_space *mapping,
			    loff_t pos, unsigned len, unsigned flags,
			    struct page **pagep, void **fsdata)
{
	struct inode *inode = file->f_dentry->d_inode;
	struct page *page;
	pgoff_t index = pos >> PAGE_CACHE_SHIFT;
	int r;

	do {
1044
		/* get a page */
1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058
		page = grab_cache_page_write_begin(mapping, index, 0);
		if (!page)
			return -ENOMEM;
		*pagep = page;

		dout("write_begin file %p inode %p page %p %d~%d\n", file,
	     	inode, page, (int)pos, (int)len);

		r = ceph_update_writeable_page(file, pos, len, page);
	} while (r == -EAGAIN);

	return r;
}

S
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1059 1060 1061 1062 1063 1064 1065 1066 1067 1068
/*
 * we don't do anything in here that simple_write_end doesn't do
 * except adjust dirty page accounting and drop read lock on
 * mdsc->snap_rwsem.
 */
static int ceph_write_end(struct file *file, struct address_space *mapping,
			  loff_t pos, unsigned len, unsigned copied,
			  struct page *page, void *fsdata)
{
	struct inode *inode = file->f_dentry->d_inode;
Y
Yehuda Sadeh 已提交
1069 1070
	struct ceph_client *client = ceph_inode_to_client(inode);
	struct ceph_mds_client *mdsc = &client->mdsc;
S
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1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151
	unsigned from = pos & (PAGE_CACHE_SIZE - 1);
	int check_cap = 0;

	dout("write_end file %p inode %p page %p %d~%d (%d)\n", file,
	     inode, page, (int)pos, (int)copied, (int)len);

	/* zero the stale part of the page if we did a short copy */
	if (copied < len)
		zero_user_segment(page, from+copied, len);

	/* did file size increase? */
	/* (no need for i_size_read(); we caller holds i_mutex */
	if (pos+copied > inode->i_size)
		check_cap = ceph_inode_set_size(inode, pos+copied);

	if (!PageUptodate(page))
		SetPageUptodate(page);

	set_page_dirty(page);

	unlock_page(page);
	up_read(&mdsc->snap_rwsem);
	page_cache_release(page);

	if (check_cap)
		ceph_check_caps(ceph_inode(inode), CHECK_CAPS_AUTHONLY, NULL);

	return copied;
}

/*
 * we set .direct_IO to indicate direct io is supported, but since we
 * intercept O_DIRECT reads and writes early, this function should
 * never get called.
 */
static ssize_t ceph_direct_io(int rw, struct kiocb *iocb,
			      const struct iovec *iov,
			      loff_t pos, unsigned long nr_segs)
{
	WARN_ON(1);
	return -EINVAL;
}

const struct address_space_operations ceph_aops = {
	.readpage = ceph_readpage,
	.readpages = ceph_readpages,
	.writepage = ceph_writepage,
	.writepages = ceph_writepages_start,
	.write_begin = ceph_write_begin,
	.write_end = ceph_write_end,
	.set_page_dirty = ceph_set_page_dirty,
	.invalidatepage = ceph_invalidatepage,
	.releasepage = ceph_releasepage,
	.direct_IO = ceph_direct_io,
};


/*
 * vm ops
 */

/*
 * Reuse write_begin here for simplicity.
 */
static int ceph_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
{
	struct inode *inode = vma->vm_file->f_dentry->d_inode;
	struct page *page = vmf->page;
	struct ceph_mds_client *mdsc = &ceph_inode_to_client(inode)->mdsc;
	loff_t off = page->index << PAGE_CACHE_SHIFT;
	loff_t size, len;
	int ret;

	size = i_size_read(inode);
	if (off + PAGE_CACHE_SIZE <= size)
		len = PAGE_CACHE_SIZE;
	else
		len = size & ~PAGE_CACHE_MASK;

	dout("page_mkwrite %p %llu~%llu page %p idx %lu\n", inode,
	     off, len, page, page->index);
1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162

	lock_page(page);

	ret = VM_FAULT_NOPAGE;
	if ((off > size) ||
	    (page->mapping != inode->i_mapping))
		goto out;

	ret = ceph_update_writeable_page(vma->vm_file, off, len, page);
	if (ret == 0) {
		/* success.  we'll keep the page locked. */
S
Sage Weil 已提交
1163 1164 1165 1166
		set_page_dirty(page);
		up_read(&mdsc->snap_rwsem);
		ret = VM_FAULT_LOCKED;
	} else {
1167 1168 1169 1170
		if (ret == -ENOMEM)
			ret = VM_FAULT_OOM;
		else
			ret = VM_FAULT_SIGBUS;
S
Sage Weil 已提交
1171
	}
1172
out:
S
Sage Weil 已提交
1173
	dout("page_mkwrite %p %llu~%llu = %d\n", inode, off, len, ret);
1174 1175
	if (ret != VM_FAULT_LOCKED)
		unlock_page(page);
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1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194
	return ret;
}

static struct vm_operations_struct ceph_vmops = {
	.fault		= filemap_fault,
	.page_mkwrite	= ceph_page_mkwrite,
};

int ceph_mmap(struct file *file, struct vm_area_struct *vma)
{
	struct address_space *mapping = file->f_mapping;

	if (!mapping->a_ops->readpage)
		return -ENOEXEC;
	file_accessed(file);
	vma->vm_ops = &ceph_vmops;
	vma->vm_flags |= VM_CAN_NONLINEAR;
	return 0;
}