xref: /openbmc/linux/fs/ceph/addr.c (revision e63dc5c7)
11d3576fdSSage Weil #include "ceph_debug.h"
21d3576fdSSage Weil 
31d3576fdSSage Weil #include <linux/backing-dev.h>
41d3576fdSSage Weil #include <linux/fs.h>
51d3576fdSSage Weil #include <linux/mm.h>
61d3576fdSSage Weil #include <linux/pagemap.h>
71d3576fdSSage Weil #include <linux/writeback.h>	/* generic_writepages */
81d3576fdSSage Weil #include <linux/pagevec.h>
91d3576fdSSage Weil #include <linux/task_io_accounting_ops.h>
101d3576fdSSage Weil 
111d3576fdSSage Weil #include "super.h"
121d3576fdSSage Weil #include "osd_client.h"
131d3576fdSSage Weil 
141d3576fdSSage Weil /*
151d3576fdSSage Weil  * Ceph address space ops.
161d3576fdSSage Weil  *
171d3576fdSSage Weil  * There are a few funny things going on here.
181d3576fdSSage Weil  *
191d3576fdSSage Weil  * The page->private field is used to reference a struct
201d3576fdSSage Weil  * ceph_snap_context for _every_ dirty page.  This indicates which
211d3576fdSSage Weil  * snapshot the page was logically dirtied in, and thus which snap
221d3576fdSSage Weil  * context needs to be associated with the osd write during writeback.
231d3576fdSSage Weil  *
241d3576fdSSage Weil  * Similarly, struct ceph_inode_info maintains a set of counters to
251d3576fdSSage Weil  * count dirty pages on the inode.  In the absense of snapshots,
261d3576fdSSage Weil  * i_wrbuffer_ref == i_wrbuffer_ref_head == the dirty page count.
271d3576fdSSage Weil  *
281d3576fdSSage Weil  * When a snapshot is taken (that is, when the client receives
291d3576fdSSage Weil  * notification that a snapshot was taken), each inode with caps and
301d3576fdSSage Weil  * with dirty pages (dirty pages implies there is a cap) gets a new
311d3576fdSSage Weil  * ceph_cap_snap in the i_cap_snaps list (which is sorted in ascending
321d3576fdSSage Weil  * order, new snaps go to the tail).  The i_wrbuffer_ref_head count is
331d3576fdSSage Weil  * moved to capsnap->dirty. (Unless a sync write is currently in
341d3576fdSSage Weil  * progress.  In that case, the capsnap is said to be "pending", new
351d3576fdSSage Weil  * writes cannot start, and the capsnap isn't "finalized" until the
361d3576fdSSage Weil  * write completes (or fails) and a final size/mtime for the inode for
371d3576fdSSage Weil  * that snap can be settled upon.)  i_wrbuffer_ref_head is reset to 0.
381d3576fdSSage Weil  *
391d3576fdSSage Weil  * On writeback, we must submit writes to the osd IN SNAP ORDER.  So,
401d3576fdSSage Weil  * we look for the first capsnap in i_cap_snaps and write out pages in
411d3576fdSSage Weil  * that snap context _only_.  Then we move on to the next capsnap,
421d3576fdSSage Weil  * eventually reaching the "live" or "head" context (i.e., pages that
431d3576fdSSage Weil  * are not yet snapped) and are writing the most recently dirtied
441d3576fdSSage Weil  * pages.
451d3576fdSSage Weil  *
461d3576fdSSage Weil  * Invalidate and so forth must take care to ensure the dirty page
471d3576fdSSage Weil  * accounting is preserved.
481d3576fdSSage Weil  */
491d3576fdSSage Weil 
502baba250SYehuda Sadeh #define CONGESTION_ON_THRESH(congestion_kb) (congestion_kb >> (PAGE_SHIFT-10))
512baba250SYehuda Sadeh #define CONGESTION_OFF_THRESH(congestion_kb)				\
522baba250SYehuda Sadeh 	(CONGESTION_ON_THRESH(congestion_kb) -				\
532baba250SYehuda Sadeh 	 (CONGESTION_ON_THRESH(congestion_kb) >> 2))
542baba250SYehuda Sadeh 
552baba250SYehuda Sadeh 
561d3576fdSSage Weil 
571d3576fdSSage Weil /*
581d3576fdSSage Weil  * Dirty a page.  Optimistically adjust accounting, on the assumption
591d3576fdSSage Weil  * that we won't race with invalidate.  If we do, readjust.
601d3576fdSSage Weil  */
611d3576fdSSage Weil static int ceph_set_page_dirty(struct page *page)
621d3576fdSSage Weil {
631d3576fdSSage Weil 	struct address_space *mapping = page->mapping;
641d3576fdSSage Weil 	struct inode *inode;
651d3576fdSSage Weil 	struct ceph_inode_info *ci;
661d3576fdSSage Weil 	int undo = 0;
671d3576fdSSage Weil 	struct ceph_snap_context *snapc;
681d3576fdSSage Weil 
691d3576fdSSage Weil 	if (unlikely(!mapping))
701d3576fdSSage Weil 		return !TestSetPageDirty(page);
711d3576fdSSage Weil 
721d3576fdSSage Weil 	if (TestSetPageDirty(page)) {
731d3576fdSSage Weil 		dout("%p set_page_dirty %p idx %lu -- already dirty\n",
741d3576fdSSage Weil 		     mapping->host, page, page->index);
751d3576fdSSage Weil 		return 0;
761d3576fdSSage Weil 	}
771d3576fdSSage Weil 
781d3576fdSSage Weil 	inode = mapping->host;
791d3576fdSSage Weil 	ci = ceph_inode(inode);
801d3576fdSSage Weil 
811d3576fdSSage Weil 	/*
821d3576fdSSage Weil 	 * Note that we're grabbing a snapc ref here without holding
831d3576fdSSage Weil 	 * any locks!
841d3576fdSSage Weil 	 */
851d3576fdSSage Weil 	snapc = ceph_get_snap_context(ci->i_snap_realm->cached_context);
861d3576fdSSage Weil 
871d3576fdSSage Weil 	/* dirty the head */
881d3576fdSSage Weil 	spin_lock(&inode->i_lock);
891d3576fdSSage Weil 	if (ci->i_wrbuffer_ref_head == 0)
901d3576fdSSage Weil 		ci->i_head_snapc = ceph_get_snap_context(snapc);
911d3576fdSSage Weil 	++ci->i_wrbuffer_ref_head;
921d3576fdSSage Weil 	if (ci->i_wrbuffer_ref == 0)
931d3576fdSSage Weil 		igrab(inode);
941d3576fdSSage Weil 	++ci->i_wrbuffer_ref;
951d3576fdSSage Weil 	dout("%p set_page_dirty %p idx %lu head %d/%d -> %d/%d "
961d3576fdSSage Weil 	     "snapc %p seq %lld (%d snaps)\n",
971d3576fdSSage Weil 	     mapping->host, page, page->index,
981d3576fdSSage Weil 	     ci->i_wrbuffer_ref-1, ci->i_wrbuffer_ref_head-1,
991d3576fdSSage Weil 	     ci->i_wrbuffer_ref, ci->i_wrbuffer_ref_head,
1001d3576fdSSage Weil 	     snapc, snapc->seq, snapc->num_snaps);
1011d3576fdSSage Weil 	spin_unlock(&inode->i_lock);
1021d3576fdSSage Weil 
1031d3576fdSSage Weil 	/* now adjust page */
1041d3576fdSSage Weil 	spin_lock_irq(&mapping->tree_lock);
1051d3576fdSSage Weil 	if (page->mapping) {	/* Race with truncate? */
1061d3576fdSSage Weil 		WARN_ON_ONCE(!PageUptodate(page));
1071d3576fdSSage Weil 
1081d3576fdSSage Weil 		if (mapping_cap_account_dirty(mapping)) {
1091d3576fdSSage Weil 			__inc_zone_page_state(page, NR_FILE_DIRTY);
1101d3576fdSSage Weil 			__inc_bdi_stat(mapping->backing_dev_info,
1111d3576fdSSage Weil 					BDI_RECLAIMABLE);
1121d3576fdSSage Weil 			task_io_account_write(PAGE_CACHE_SIZE);
1131d3576fdSSage Weil 		}
1141d3576fdSSage Weil 		radix_tree_tag_set(&mapping->page_tree,
1151d3576fdSSage Weil 				page_index(page), PAGECACHE_TAG_DIRTY);
1161d3576fdSSage Weil 
1171d3576fdSSage Weil 		/*
1181d3576fdSSage Weil 		 * Reference snap context in page->private.  Also set
1191d3576fdSSage Weil 		 * PagePrivate so that we get invalidatepage callback.
1201d3576fdSSage Weil 		 */
1211d3576fdSSage Weil 		page->private = (unsigned long)snapc;
1221d3576fdSSage Weil 		SetPagePrivate(page);
1231d3576fdSSage Weil 	} else {
1241d3576fdSSage Weil 		dout("ANON set_page_dirty %p (raced truncate?)\n", page);
1251d3576fdSSage Weil 		undo = 1;
1261d3576fdSSage Weil 	}
1271d3576fdSSage Weil 
1281d3576fdSSage Weil 	spin_unlock_irq(&mapping->tree_lock);
1291d3576fdSSage Weil 
1301d3576fdSSage Weil 	if (undo)
1311d3576fdSSage Weil 		/* whoops, we failed to dirty the page */
1321d3576fdSSage Weil 		ceph_put_wrbuffer_cap_refs(ci, 1, snapc);
1331d3576fdSSage Weil 
1341d3576fdSSage Weil 	__mark_inode_dirty(mapping->host, I_DIRTY_PAGES);
1351d3576fdSSage Weil 
1361d3576fdSSage Weil 	BUG_ON(!PageDirty(page));
1371d3576fdSSage Weil 	return 1;
1381d3576fdSSage Weil }
1391d3576fdSSage Weil 
1401d3576fdSSage Weil /*
1411d3576fdSSage Weil  * If we are truncating the full page (i.e. offset == 0), adjust the
1421d3576fdSSage Weil  * dirty page counters appropriately.  Only called if there is private
1431d3576fdSSage Weil  * data on the page.
1441d3576fdSSage Weil  */
1451d3576fdSSage Weil static void ceph_invalidatepage(struct page *page, unsigned long offset)
1461d3576fdSSage Weil {
1471d3576fdSSage Weil 	struct inode *inode = page->mapping->host;
1481d3576fdSSage Weil 	struct ceph_inode_info *ci;
1491d3576fdSSage Weil 	struct ceph_snap_context *snapc = (void *)page->private;
1501d3576fdSSage Weil 
1511d3576fdSSage Weil 	BUG_ON(!PageLocked(page));
1521d3576fdSSage Weil 	BUG_ON(!page->private);
1531d3576fdSSage Weil 	BUG_ON(!PagePrivate(page));
1541d3576fdSSage Weil 	BUG_ON(!page->mapping);
1551d3576fdSSage Weil 
1561d3576fdSSage Weil 	/*
1571d3576fdSSage Weil 	 * We can get non-dirty pages here due to races between
1581d3576fdSSage Weil 	 * set_page_dirty and truncate_complete_page; just spit out a
1591d3576fdSSage Weil 	 * warning, in case we end up with accounting problems later.
1601d3576fdSSage Weil 	 */
1611d3576fdSSage Weil 	if (!PageDirty(page))
1621d3576fdSSage Weil 		pr_err("%p invalidatepage %p page not dirty\n", inode, page);
1631d3576fdSSage Weil 
1641d3576fdSSage Weil 	if (offset == 0)
1651d3576fdSSage Weil 		ClearPageChecked(page);
1661d3576fdSSage Weil 
1671d3576fdSSage Weil 	ci = ceph_inode(inode);
1681d3576fdSSage Weil 	if (offset == 0) {
1691d3576fdSSage Weil 		dout("%p invalidatepage %p idx %lu full dirty page %lu\n",
1701d3576fdSSage Weil 		     inode, page, page->index, offset);
1711d3576fdSSage Weil 		ceph_put_wrbuffer_cap_refs(ci, 1, snapc);
1721d3576fdSSage Weil 		ceph_put_snap_context(snapc);
1731d3576fdSSage Weil 		page->private = 0;
1741d3576fdSSage Weil 		ClearPagePrivate(page);
1751d3576fdSSage Weil 	} else {
1761d3576fdSSage Weil 		dout("%p invalidatepage %p idx %lu partial dirty page\n",
1771d3576fdSSage Weil 		     inode, page, page->index);
1781d3576fdSSage Weil 	}
1791d3576fdSSage Weil }
1801d3576fdSSage Weil 
1811d3576fdSSage Weil /* just a sanity check */
1821d3576fdSSage Weil static int ceph_releasepage(struct page *page, gfp_t g)
1831d3576fdSSage Weil {
1841d3576fdSSage Weil 	struct inode *inode = page->mapping ? page->mapping->host : NULL;
1851d3576fdSSage Weil 	dout("%p releasepage %p idx %lu\n", inode, page, page->index);
1861d3576fdSSage Weil 	WARN_ON(PageDirty(page));
1871d3576fdSSage Weil 	WARN_ON(page->private);
1881d3576fdSSage Weil 	WARN_ON(PagePrivate(page));
1891d3576fdSSage Weil 	return 0;
1901d3576fdSSage Weil }
1911d3576fdSSage Weil 
1921d3576fdSSage Weil /*
1931d3576fdSSage Weil  * read a single page, without unlocking it.
1941d3576fdSSage Weil  */
1951d3576fdSSage Weil static int readpage_nounlock(struct file *filp, struct page *page)
1961d3576fdSSage Weil {
1971d3576fdSSage Weil 	struct inode *inode = filp->f_dentry->d_inode;
1981d3576fdSSage Weil 	struct ceph_inode_info *ci = ceph_inode(inode);
1991d3576fdSSage Weil 	struct ceph_osd_client *osdc = &ceph_inode_to_client(inode)->osdc;
2001d3576fdSSage Weil 	int err = 0;
2011d3576fdSSage Weil 	u64 len = PAGE_CACHE_SIZE;
2021d3576fdSSage Weil 
2031d3576fdSSage Weil 	dout("readpage inode %p file %p page %p index %lu\n",
2041d3576fdSSage Weil 	     inode, filp, page, page->index);
2051d3576fdSSage Weil 	err = ceph_osdc_readpages(osdc, ceph_vino(inode), &ci->i_layout,
2061d3576fdSSage Weil 				  page->index << PAGE_CACHE_SHIFT, &len,
2071d3576fdSSage Weil 				  ci->i_truncate_seq, ci->i_truncate_size,
2081d3576fdSSage Weil 				  &page, 1);
2091d3576fdSSage Weil 	if (err == -ENOENT)
2101d3576fdSSage Weil 		err = 0;
2111d3576fdSSage Weil 	if (err < 0) {
2121d3576fdSSage Weil 		SetPageError(page);
2131d3576fdSSage Weil 		goto out;
2141d3576fdSSage Weil 	} else if (err < PAGE_CACHE_SIZE) {
2151d3576fdSSage Weil 		/* zero fill remainder of page */
2161d3576fdSSage Weil 		zero_user_segment(page, err, PAGE_CACHE_SIZE);
2171d3576fdSSage Weil 	}
2181d3576fdSSage Weil 	SetPageUptodate(page);
2191d3576fdSSage Weil 
2201d3576fdSSage Weil out:
2211d3576fdSSage Weil 	return err < 0 ? err : 0;
2221d3576fdSSage Weil }
2231d3576fdSSage Weil 
2241d3576fdSSage Weil static int ceph_readpage(struct file *filp, struct page *page)
2251d3576fdSSage Weil {
2261d3576fdSSage Weil 	int r = readpage_nounlock(filp, page);
2271d3576fdSSage Weil 	unlock_page(page);
2281d3576fdSSage Weil 	return r;
2291d3576fdSSage Weil }
2301d3576fdSSage Weil 
2311d3576fdSSage Weil /*
2321d3576fdSSage Weil  * Build a vector of contiguous pages from the provided page list.
2331d3576fdSSage Weil  */
2341d3576fdSSage Weil static struct page **page_vector_from_list(struct list_head *page_list,
2351d3576fdSSage Weil 					   unsigned *nr_pages)
2361d3576fdSSage Weil {
2371d3576fdSSage Weil 	struct page **pages;
2381d3576fdSSage Weil 	struct page *page;
2391d3576fdSSage Weil 	int next_index, contig_pages = 0;
2401d3576fdSSage Weil 
2411d3576fdSSage Weil 	/* build page vector */
2421d3576fdSSage Weil 	pages = kmalloc(sizeof(*pages) * *nr_pages, GFP_NOFS);
2431d3576fdSSage Weil 	if (!pages)
2441d3576fdSSage Weil 		return ERR_PTR(-ENOMEM);
2451d3576fdSSage Weil 
2461d3576fdSSage Weil 	BUG_ON(list_empty(page_list));
2471d3576fdSSage Weil 	next_index = list_entry(page_list->prev, struct page, lru)->index;
2481d3576fdSSage Weil 	list_for_each_entry_reverse(page, page_list, lru) {
2491d3576fdSSage Weil 		if (page->index == next_index) {
2501d3576fdSSage Weil 			dout("readpages page %d %p\n", contig_pages, page);
2511d3576fdSSage Weil 			pages[contig_pages] = page;
2521d3576fdSSage Weil 			contig_pages++;
2531d3576fdSSage Weil 			next_index++;
2541d3576fdSSage Weil 		} else {
2551d3576fdSSage Weil 			break;
2561d3576fdSSage Weil 		}
2571d3576fdSSage Weil 	}
2581d3576fdSSage Weil 	*nr_pages = contig_pages;
2591d3576fdSSage Weil 	return pages;
2601d3576fdSSage Weil }
2611d3576fdSSage Weil 
2621d3576fdSSage Weil /*
2631d3576fdSSage Weil  * Read multiple pages.  Leave pages we don't read + unlock in page_list;
2641d3576fdSSage Weil  * the caller (VM) cleans them up.
2651d3576fdSSage Weil  */
2661d3576fdSSage Weil static int ceph_readpages(struct file *file, struct address_space *mapping,
2671d3576fdSSage Weil 			  struct list_head *page_list, unsigned nr_pages)
2681d3576fdSSage Weil {
2691d3576fdSSage Weil 	struct inode *inode = file->f_dentry->d_inode;
2701d3576fdSSage Weil 	struct ceph_inode_info *ci = ceph_inode(inode);
2711d3576fdSSage Weil 	struct ceph_osd_client *osdc = &ceph_inode_to_client(inode)->osdc;
2721d3576fdSSage Weil 	int rc = 0;
2731d3576fdSSage Weil 	struct page **pages;
2741d3576fdSSage Weil 	struct pagevec pvec;
2751d3576fdSSage Weil 	loff_t offset;
2761d3576fdSSage Weil 	u64 len;
2771d3576fdSSage Weil 
2781d3576fdSSage Weil 	dout("readpages %p file %p nr_pages %d\n",
2791d3576fdSSage Weil 	     inode, file, nr_pages);
2801d3576fdSSage Weil 
2811d3576fdSSage Weil 	pages = page_vector_from_list(page_list, &nr_pages);
2821d3576fdSSage Weil 	if (IS_ERR(pages))
2831d3576fdSSage Weil 		return PTR_ERR(pages);
2841d3576fdSSage Weil 
2851d3576fdSSage Weil 	/* guess read extent */
2861d3576fdSSage Weil 	offset = pages[0]->index << PAGE_CACHE_SHIFT;
2871d3576fdSSage Weil 	len = nr_pages << PAGE_CACHE_SHIFT;
2881d3576fdSSage Weil 	rc = ceph_osdc_readpages(osdc, ceph_vino(inode), &ci->i_layout,
2891d3576fdSSage Weil 				 offset, &len,
2901d3576fdSSage Weil 				 ci->i_truncate_seq, ci->i_truncate_size,
2911d3576fdSSage Weil 				 pages, nr_pages);
2921d3576fdSSage Weil 	if (rc == -ENOENT)
2931d3576fdSSage Weil 		rc = 0;
2941d3576fdSSage Weil 	if (rc < 0)
2951d3576fdSSage Weil 		goto out;
2961d3576fdSSage Weil 
2971d3576fdSSage Weil 	/* set uptodate and add to lru in pagevec-sized chunks */
2981d3576fdSSage Weil 	pagevec_init(&pvec, 0);
2991d3576fdSSage Weil 	for (; !list_empty(page_list) && len > 0;
3001d3576fdSSage Weil 	     rc -= PAGE_CACHE_SIZE, len -= PAGE_CACHE_SIZE) {
3011d3576fdSSage Weil 		struct page *page =
3021d3576fdSSage Weil 			list_entry(page_list->prev, struct page, lru);
3031d3576fdSSage Weil 
3041d3576fdSSage Weil 		list_del(&page->lru);
3051d3576fdSSage Weil 
3061d3576fdSSage Weil 		if (rc < (int)PAGE_CACHE_SIZE) {
3071d3576fdSSage Weil 			/* zero (remainder of) page */
3081d3576fdSSage Weil 			int s = rc < 0 ? 0 : rc;
3091d3576fdSSage Weil 			zero_user_segment(page, s, PAGE_CACHE_SIZE);
3101d3576fdSSage Weil 		}
3111d3576fdSSage Weil 
3121d3576fdSSage Weil 		if (add_to_page_cache(page, mapping, page->index, GFP_NOFS)) {
3131d3576fdSSage Weil 			page_cache_release(page);
3141d3576fdSSage Weil 			dout("readpages %p add_to_page_cache failed %p\n",
3151d3576fdSSage Weil 			     inode, page);
3161d3576fdSSage Weil 			continue;
3171d3576fdSSage Weil 		}
3181d3576fdSSage Weil 		dout("readpages %p adding %p idx %lu\n", inode, page,
3191d3576fdSSage Weil 		     page->index);
3201d3576fdSSage Weil 		flush_dcache_page(page);
3211d3576fdSSage Weil 		SetPageUptodate(page);
3221d3576fdSSage Weil 		unlock_page(page);
3231d3576fdSSage Weil 		if (pagevec_add(&pvec, page) == 0)
3241d3576fdSSage Weil 			pagevec_lru_add_file(&pvec);   /* add to lru */
3251d3576fdSSage Weil 	}
3261d3576fdSSage Weil 	pagevec_lru_add_file(&pvec);
3271d3576fdSSage Weil 	rc = 0;
3281d3576fdSSage Weil 
3291d3576fdSSage Weil out:
3301d3576fdSSage Weil 	kfree(pages);
3311d3576fdSSage Weil 	return rc;
3321d3576fdSSage Weil }
3331d3576fdSSage Weil 
3341d3576fdSSage Weil /*
3351d3576fdSSage Weil  * Get ref for the oldest snapc for an inode with dirty data... that is, the
3361d3576fdSSage Weil  * only snap context we are allowed to write back.
3371d3576fdSSage Weil  *
3381d3576fdSSage Weil  * Caller holds i_lock.
3391d3576fdSSage Weil  */
3401d3576fdSSage Weil static struct ceph_snap_context *__get_oldest_context(struct inode *inode,
3411d3576fdSSage Weil 						      u64 *snap_size)
3421d3576fdSSage Weil {
3431d3576fdSSage Weil 	struct ceph_inode_info *ci = ceph_inode(inode);
3441d3576fdSSage Weil 	struct ceph_snap_context *snapc = NULL;
3451d3576fdSSage Weil 	struct ceph_cap_snap *capsnap = NULL;
3461d3576fdSSage Weil 
3471d3576fdSSage Weil 	list_for_each_entry(capsnap, &ci->i_cap_snaps, ci_item) {
3481d3576fdSSage Weil 		dout(" cap_snap %p snapc %p has %d dirty pages\n", capsnap,
3491d3576fdSSage Weil 		     capsnap->context, capsnap->dirty_pages);
3501d3576fdSSage Weil 		if (capsnap->dirty_pages) {
3511d3576fdSSage Weil 			snapc = ceph_get_snap_context(capsnap->context);
3521d3576fdSSage Weil 			if (snap_size)
3531d3576fdSSage Weil 				*snap_size = capsnap->size;
3541d3576fdSSage Weil 			break;
3551d3576fdSSage Weil 		}
3561d3576fdSSage Weil 	}
3571d3576fdSSage Weil 	if (!snapc && ci->i_snap_realm) {
3581d3576fdSSage Weil 		snapc = ceph_get_snap_context(ci->i_snap_realm->cached_context);
3591d3576fdSSage Weil 		dout(" head snapc %p has %d dirty pages\n",
3601d3576fdSSage Weil 		     snapc, ci->i_wrbuffer_ref_head);
3611d3576fdSSage Weil 	}
3621d3576fdSSage Weil 	return snapc;
3631d3576fdSSage Weil }
3641d3576fdSSage Weil 
3651d3576fdSSage Weil static struct ceph_snap_context *get_oldest_context(struct inode *inode,
3661d3576fdSSage Weil 						    u64 *snap_size)
3671d3576fdSSage Weil {
3681d3576fdSSage Weil 	struct ceph_snap_context *snapc = NULL;
3691d3576fdSSage Weil 
3701d3576fdSSage Weil 	spin_lock(&inode->i_lock);
3711d3576fdSSage Weil 	snapc = __get_oldest_context(inode, snap_size);
3721d3576fdSSage Weil 	spin_unlock(&inode->i_lock);
3731d3576fdSSage Weil 	return snapc;
3741d3576fdSSage Weil }
3751d3576fdSSage Weil 
3761d3576fdSSage Weil /*
3771d3576fdSSage Weil  * Write a single page, but leave the page locked.
3781d3576fdSSage Weil  *
3791d3576fdSSage Weil  * If we get a write error, set the page error bit, but still adjust the
3801d3576fdSSage Weil  * dirty page accounting (i.e., page is no longer dirty).
3811d3576fdSSage Weil  */
3821d3576fdSSage Weil static int writepage_nounlock(struct page *page, struct writeback_control *wbc)
3831d3576fdSSage Weil {
3841d3576fdSSage Weil 	struct inode *inode;
3851d3576fdSSage Weil 	struct ceph_inode_info *ci;
3862baba250SYehuda Sadeh 	struct ceph_client *client;
3871d3576fdSSage Weil 	struct ceph_osd_client *osdc;
3881d3576fdSSage Weil 	loff_t page_off = page->index << PAGE_CACHE_SHIFT;
3891d3576fdSSage Weil 	int len = PAGE_CACHE_SIZE;
3901d3576fdSSage Weil 	loff_t i_size;
3911d3576fdSSage Weil 	int err = 0;
3921d3576fdSSage Weil 	struct ceph_snap_context *snapc;
3931d3576fdSSage Weil 	u64 snap_size = 0;
3942baba250SYehuda Sadeh 	long writeback_stat;
3951d3576fdSSage Weil 
3961d3576fdSSage Weil 	dout("writepage %p idx %lu\n", page, page->index);
3971d3576fdSSage Weil 
3981d3576fdSSage Weil 	if (!page->mapping || !page->mapping->host) {
3991d3576fdSSage Weil 		dout("writepage %p - no mapping\n", page);
4001d3576fdSSage Weil 		return -EFAULT;
4011d3576fdSSage Weil 	}
4021d3576fdSSage Weil 	inode = page->mapping->host;
4031d3576fdSSage Weil 	ci = ceph_inode(inode);
4042baba250SYehuda Sadeh 	client = ceph_inode_to_client(inode);
4052baba250SYehuda Sadeh 	osdc = &client->osdc;
4061d3576fdSSage Weil 
4071d3576fdSSage Weil 	/* verify this is a writeable snap context */
4081d3576fdSSage Weil 	snapc = (void *)page->private;
4091d3576fdSSage Weil 	if (snapc == NULL) {
4101d3576fdSSage Weil 		dout("writepage %p page %p not dirty?\n", inode, page);
4111d3576fdSSage Weil 		goto out;
4121d3576fdSSage Weil 	}
4131d3576fdSSage Weil 	if (snapc != get_oldest_context(inode, &snap_size)) {
4141d3576fdSSage Weil 		dout("writepage %p page %p snapc %p not writeable - noop\n",
4151d3576fdSSage Weil 		     inode, page, (void *)page->private);
4161d3576fdSSage Weil 		/* we should only noop if called by kswapd */
4171d3576fdSSage Weil 		WARN_ON((current->flags & PF_MEMALLOC) == 0);
4181d3576fdSSage Weil 		goto out;
4191d3576fdSSage Weil 	}
4201d3576fdSSage Weil 
4211d3576fdSSage Weil 	/* is this a partial page at end of file? */
4221d3576fdSSage Weil 	if (snap_size)
4231d3576fdSSage Weil 		i_size = snap_size;
4241d3576fdSSage Weil 	else
4251d3576fdSSage Weil 		i_size = i_size_read(inode);
4261d3576fdSSage Weil 	if (i_size < page_off + len)
4271d3576fdSSage Weil 		len = i_size - page_off;
4281d3576fdSSage Weil 
4291d3576fdSSage Weil 	dout("writepage %p page %p index %lu on %llu~%u\n",
4301d3576fdSSage Weil 	     inode, page, page->index, page_off, len);
4311d3576fdSSage Weil 
4322baba250SYehuda Sadeh 	writeback_stat = atomic_long_inc_return(&client->writeback_count);
4332baba250SYehuda Sadeh 	if (writeback_stat >
4342baba250SYehuda Sadeh 	    CONGESTION_ON_THRESH(client->mount_args->congestion_kb))
4352baba250SYehuda Sadeh 		set_bdi_congested(&client->backing_dev_info, BLK_RW_ASYNC);
4362baba250SYehuda Sadeh 
4371d3576fdSSage Weil 	set_page_writeback(page);
4381d3576fdSSage Weil 	err = ceph_osdc_writepages(osdc, ceph_vino(inode),
4391d3576fdSSage Weil 				   &ci->i_layout, snapc,
4401d3576fdSSage Weil 				   page_off, len,
4411d3576fdSSage Weil 				   ci->i_truncate_seq, ci->i_truncate_size,
4421d3576fdSSage Weil 				   &inode->i_mtime,
4431d3576fdSSage Weil 				   &page, 1, 0, 0, true);
4441d3576fdSSage Weil 	if (err < 0) {
4451d3576fdSSage Weil 		dout("writepage setting page/mapping error %d %p\n", err, page);
4461d3576fdSSage Weil 		SetPageError(page);
4471d3576fdSSage Weil 		mapping_set_error(&inode->i_data, err);
4481d3576fdSSage Weil 		if (wbc)
4491d3576fdSSage Weil 			wbc->pages_skipped++;
4501d3576fdSSage Weil 	} else {
4511d3576fdSSage Weil 		dout("writepage cleaned page %p\n", page);
4521d3576fdSSage Weil 		err = 0;  /* vfs expects us to return 0 */
4531d3576fdSSage Weil 	}
4541d3576fdSSage Weil 	page->private = 0;
4551d3576fdSSage Weil 	ClearPagePrivate(page);
4561d3576fdSSage Weil 	end_page_writeback(page);
4571d3576fdSSage Weil 	ceph_put_wrbuffer_cap_refs(ci, 1, snapc);
4581d3576fdSSage Weil 	ceph_put_snap_context(snapc);
4591d3576fdSSage Weil out:
4601d3576fdSSage Weil 	return err;
4611d3576fdSSage Weil }
4621d3576fdSSage Weil 
4631d3576fdSSage Weil static int ceph_writepage(struct page *page, struct writeback_control *wbc)
4641d3576fdSSage Weil {
465dbd646a8SYehuda Sadeh 	int err;
466dbd646a8SYehuda Sadeh 	struct inode *inode = page->mapping->host;
467dbd646a8SYehuda Sadeh 	BUG_ON(!inode);
468dbd646a8SYehuda Sadeh 	igrab(inode);
469dbd646a8SYehuda Sadeh 	err = writepage_nounlock(page, wbc);
4701d3576fdSSage Weil 	unlock_page(page);
471dbd646a8SYehuda Sadeh 	iput(inode);
4721d3576fdSSage Weil 	return err;
4731d3576fdSSage Weil }
4741d3576fdSSage Weil 
4751d3576fdSSage Weil 
4761d3576fdSSage Weil /*
4771d3576fdSSage Weil  * lame release_pages helper.  release_pages() isn't exported to
4781d3576fdSSage Weil  * modules.
4791d3576fdSSage Weil  */
4801d3576fdSSage Weil static void ceph_release_pages(struct page **pages, int num)
4811d3576fdSSage Weil {
4821d3576fdSSage Weil 	struct pagevec pvec;
4831d3576fdSSage Weil 	int i;
4841d3576fdSSage Weil 
4851d3576fdSSage Weil 	pagevec_init(&pvec, 0);
4861d3576fdSSage Weil 	for (i = 0; i < num; i++) {
4871d3576fdSSage Weil 		if (pagevec_add(&pvec, pages[i]) == 0)
4881d3576fdSSage Weil 			pagevec_release(&pvec);
4891d3576fdSSage Weil 	}
4901d3576fdSSage Weil 	pagevec_release(&pvec);
4911d3576fdSSage Weil }
4921d3576fdSSage Weil 
4931d3576fdSSage Weil 
4941d3576fdSSage Weil /*
4951d3576fdSSage Weil  * async writeback completion handler.
4961d3576fdSSage Weil  *
4971d3576fdSSage Weil  * If we get an error, set the mapping error bit, but not the individual
4981d3576fdSSage Weil  * page error bits.
4991d3576fdSSage Weil  */
5001d3576fdSSage Weil static void writepages_finish(struct ceph_osd_request *req,
5011d3576fdSSage Weil 			      struct ceph_msg *msg)
5021d3576fdSSage Weil {
5031d3576fdSSage Weil 	struct inode *inode = req->r_inode;
5041d3576fdSSage Weil 	struct ceph_osd_reply_head *replyhead;
5051d3576fdSSage Weil 	struct ceph_osd_op *op;
5061d3576fdSSage Weil 	struct ceph_inode_info *ci = ceph_inode(inode);
5071d3576fdSSage Weil 	unsigned wrote;
5081d3576fdSSage Weil 	struct page *page;
5091d3576fdSSage Weil 	int i;
5101d3576fdSSage Weil 	struct ceph_snap_context *snapc = req->r_snapc;
5111d3576fdSSage Weil 	struct address_space *mapping = inode->i_mapping;
5121d3576fdSSage Weil 	struct writeback_control *wbc = req->r_wbc;
5131d3576fdSSage Weil 	__s32 rc = -EIO;
5141d3576fdSSage Weil 	u64 bytes = 0;
5152baba250SYehuda Sadeh 	struct ceph_client *client = ceph_inode_to_client(inode);
5162baba250SYehuda Sadeh 	long writeback_stat;
517e63dc5c7SYehuda Sadeh 	unsigned issued = __ceph_caps_issued(ci, NULL);
5181d3576fdSSage Weil 
5191d3576fdSSage Weil 	/* parse reply */
5201d3576fdSSage Weil 	replyhead = msg->front.iov_base;
5211d3576fdSSage Weil 	WARN_ON(le32_to_cpu(replyhead->num_ops) == 0);
5221d3576fdSSage Weil 	op = (void *)(replyhead + 1);
5231d3576fdSSage Weil 	rc = le32_to_cpu(replyhead->result);
5241d3576fdSSage Weil 	bytes = le64_to_cpu(op->extent.length);
5251d3576fdSSage Weil 
5261d3576fdSSage Weil 	if (rc >= 0) {
52779788c69SSage Weil 		/*
52879788c69SSage Weil 		 * Assume we wrote the pages we originally sent.  The
52979788c69SSage Weil 		 * osd might reply with fewer pages if our writeback
53079788c69SSage Weil 		 * raced with a truncation and was adjusted at the osd,
53179788c69SSage Weil 		 * so don't believe the reply.
53279788c69SSage Weil 		 */
53379788c69SSage Weil 		wrote = req->r_num_pages;
5341d3576fdSSage Weil 	} else {
5351d3576fdSSage Weil 		wrote = 0;
5361d3576fdSSage Weil 		mapping_set_error(mapping, rc);
5371d3576fdSSage Weil 	}
5381d3576fdSSage Weil 	dout("writepages_finish %p rc %d bytes %llu wrote %d (pages)\n",
5391d3576fdSSage Weil 	     inode, rc, bytes, wrote);
5401d3576fdSSage Weil 
5411d3576fdSSage Weil 	/* clean all pages */
5421d3576fdSSage Weil 	for (i = 0; i < req->r_num_pages; i++) {
5431d3576fdSSage Weil 		page = req->r_pages[i];
5441d3576fdSSage Weil 		BUG_ON(!page);
5451d3576fdSSage Weil 		WARN_ON(!PageUptodate(page));
5461d3576fdSSage Weil 
5472baba250SYehuda Sadeh 		writeback_stat =
5482baba250SYehuda Sadeh 			atomic_long_dec_return(&client->writeback_count);
5492baba250SYehuda Sadeh 		if (writeback_stat <
5502baba250SYehuda Sadeh 		    CONGESTION_OFF_THRESH(client->mount_args->congestion_kb))
5512baba250SYehuda Sadeh 			clear_bdi_congested(&client->backing_dev_info,
5522baba250SYehuda Sadeh 					    BLK_RW_ASYNC);
5532baba250SYehuda Sadeh 
5541d3576fdSSage Weil 		if (i >= wrote) {
5551d3576fdSSage Weil 			dout("inode %p skipping page %p\n", inode, page);
5561d3576fdSSage Weil 			wbc->pages_skipped++;
5571d3576fdSSage Weil 		}
5581d3576fdSSage Weil 		page->private = 0;
5591d3576fdSSage Weil 		ClearPagePrivate(page);
5601d3576fdSSage Weil 		ceph_put_snap_context(snapc);
5611d3576fdSSage Weil 		dout("unlocking %d %p\n", i, page);
5621d3576fdSSage Weil 		end_page_writeback(page);
563e63dc5c7SYehuda Sadeh 
564e63dc5c7SYehuda Sadeh 		/*
565e63dc5c7SYehuda Sadeh 		 * We lost the cache cap, need to truncate the page before
566e63dc5c7SYehuda Sadeh 		 * it is unlocked, otherwise we'd truncate it later in the
567e63dc5c7SYehuda Sadeh 		 * page truncation thread, possibly losing some data that
568e63dc5c7SYehuda Sadeh 		 * raced its way in
569e63dc5c7SYehuda Sadeh 		 */
570e63dc5c7SYehuda Sadeh 		if ((issued & CEPH_CAP_FILE_CACHE) == 0)
571e63dc5c7SYehuda Sadeh 			generic_error_remove_page(inode->i_mapping, page);
572e63dc5c7SYehuda Sadeh 
5731d3576fdSSage Weil 		unlock_page(page);
5741d3576fdSSage Weil 	}
5751d3576fdSSage Weil 	dout("%p wrote+cleaned %d pages\n", inode, wrote);
5761d3576fdSSage Weil 	ceph_put_wrbuffer_cap_refs(ci, req->r_num_pages, snapc);
5771d3576fdSSage Weil 
5781d3576fdSSage Weil 	ceph_release_pages(req->r_pages, req->r_num_pages);
5791d3576fdSSage Weil 	if (req->r_pages_from_pool)
5801d3576fdSSage Weil 		mempool_free(req->r_pages,
5811d3576fdSSage Weil 			     ceph_client(inode->i_sb)->wb_pagevec_pool);
5821d3576fdSSage Weil 	else
5831d3576fdSSage Weil 		kfree(req->r_pages);
5841d3576fdSSage Weil 	ceph_osdc_put_request(req);
5851d3576fdSSage Weil }
5861d3576fdSSage Weil 
5871d3576fdSSage Weil /*
5881d3576fdSSage Weil  * allocate a page vec, either directly, or if necessary, via a the
5891d3576fdSSage Weil  * mempool.  we avoid the mempool if we can because req->r_num_pages
5901d3576fdSSage Weil  * may be less than the maximum write size.
5911d3576fdSSage Weil  */
5921d3576fdSSage Weil static void alloc_page_vec(struct ceph_client *client,
5931d3576fdSSage Weil 			   struct ceph_osd_request *req)
5941d3576fdSSage Weil {
5951d3576fdSSage Weil 	req->r_pages = kmalloc(sizeof(struct page *) * req->r_num_pages,
5961d3576fdSSage Weil 			       GFP_NOFS);
5971d3576fdSSage Weil 	if (!req->r_pages) {
5981d3576fdSSage Weil 		req->r_pages = mempool_alloc(client->wb_pagevec_pool, GFP_NOFS);
5991d3576fdSSage Weil 		req->r_pages_from_pool = 1;
6001d3576fdSSage Weil 		WARN_ON(!req->r_pages);
6011d3576fdSSage Weil 	}
6021d3576fdSSage Weil }
6031d3576fdSSage Weil 
6041d3576fdSSage Weil /*
6051d3576fdSSage Weil  * initiate async writeback
6061d3576fdSSage Weil  */
6071d3576fdSSage Weil static int ceph_writepages_start(struct address_space *mapping,
6081d3576fdSSage Weil 				 struct writeback_control *wbc)
6091d3576fdSSage Weil {
6101d3576fdSSage Weil 	struct inode *inode = mapping->host;
6111d3576fdSSage Weil 	struct backing_dev_info *bdi = mapping->backing_dev_info;
6121d3576fdSSage Weil 	struct ceph_inode_info *ci = ceph_inode(inode);
613ec7384ecSJulia Lawall 	struct ceph_client *client;
6141d3576fdSSage Weil 	pgoff_t index, start, end;
6151d3576fdSSage Weil 	int range_whole = 0;
6161d3576fdSSage Weil 	int should_loop = 1;
6171d3576fdSSage Weil 	pgoff_t max_pages = 0, max_pages_ever = 0;
6181d3576fdSSage Weil 	struct ceph_snap_context *snapc = NULL, *last_snapc = NULL;
6191d3576fdSSage Weil 	struct pagevec pvec;
6201d3576fdSSage Weil 	int done = 0;
6211d3576fdSSage Weil 	int rc = 0;
6221d3576fdSSage Weil 	unsigned wsize = 1 << inode->i_blkbits;
6231d3576fdSSage Weil 	struct ceph_osd_request *req = NULL;
6241d3576fdSSage Weil 	int do_sync;
6251d3576fdSSage Weil 	u64 snap_size = 0;
6261d3576fdSSage Weil 
6271d3576fdSSage Weil 	/*
6281d3576fdSSage Weil 	 * Include a 'sync' in the OSD request if this is a data
6291d3576fdSSage Weil 	 * integrity write (e.g., O_SYNC write or fsync()), or if our
6301d3576fdSSage Weil 	 * cap is being revoked.
6311d3576fdSSage Weil 	 */
6321d3576fdSSage Weil 	do_sync = wbc->sync_mode == WB_SYNC_ALL;
6331d3576fdSSage Weil 	if (ceph_caps_revoking(ci, CEPH_CAP_FILE_BUFFER))
6341d3576fdSSage Weil 		do_sync = 1;
6351d3576fdSSage Weil 	dout("writepages_start %p dosync=%d (mode=%s)\n",
6361d3576fdSSage Weil 	     inode, do_sync,
6371d3576fdSSage Weil 	     wbc->sync_mode == WB_SYNC_NONE ? "NONE" :
6381d3576fdSSage Weil 	     (wbc->sync_mode == WB_SYNC_ALL ? "ALL" : "HOLD"));
6391d3576fdSSage Weil 
6401d3576fdSSage Weil 	client = ceph_inode_to_client(inode);
6411d3576fdSSage Weil 	if (client->mount_state == CEPH_MOUNT_SHUTDOWN) {
6421d3576fdSSage Weil 		pr_warning("writepage_start %p on forced umount\n", inode);
6431d3576fdSSage Weil 		return -EIO; /* we're in a forced umount, don't write! */
6441d3576fdSSage Weil 	}
6456b805185SSage Weil 	if (client->mount_args->wsize && client->mount_args->wsize < wsize)
6466b805185SSage Weil 		wsize = client->mount_args->wsize;
6471d3576fdSSage Weil 	if (wsize < PAGE_CACHE_SIZE)
6481d3576fdSSage Weil 		wsize = PAGE_CACHE_SIZE;
6491d3576fdSSage Weil 	max_pages_ever = wsize >> PAGE_CACHE_SHIFT;
6501d3576fdSSage Weil 
6511d3576fdSSage Weil 	pagevec_init(&pvec, 0);
6521d3576fdSSage Weil 
6531d3576fdSSage Weil 	/* ?? */
6541d3576fdSSage Weil 	if (wbc->nonblocking && bdi_write_congested(bdi)) {
6551d3576fdSSage Weil 		dout(" writepages congested\n");
6561d3576fdSSage Weil 		wbc->encountered_congestion = 1;
6571d3576fdSSage Weil 		goto out_final;
6581d3576fdSSage Weil 	}
6591d3576fdSSage Weil 
6601d3576fdSSage Weil 	/* where to start/end? */
6611d3576fdSSage Weil 	if (wbc->range_cyclic) {
6621d3576fdSSage Weil 		start = mapping->writeback_index; /* Start from prev offset */
6631d3576fdSSage Weil 		end = -1;
6641d3576fdSSage Weil 		dout(" cyclic, start at %lu\n", start);
6651d3576fdSSage Weil 	} else {
6661d3576fdSSage Weil 		start = wbc->range_start >> PAGE_CACHE_SHIFT;
6671d3576fdSSage Weil 		end = wbc->range_end >> PAGE_CACHE_SHIFT;
6681d3576fdSSage Weil 		if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX)
6691d3576fdSSage Weil 			range_whole = 1;
6701d3576fdSSage Weil 		should_loop = 0;
6711d3576fdSSage Weil 		dout(" not cyclic, %lu to %lu\n", start, end);
6721d3576fdSSage Weil 	}
6731d3576fdSSage Weil 	index = start;
6741d3576fdSSage Weil 
6751d3576fdSSage Weil retry:
6761d3576fdSSage Weil 	/* find oldest snap context with dirty data */
6771d3576fdSSage Weil 	ceph_put_snap_context(snapc);
6781d3576fdSSage Weil 	snapc = get_oldest_context(inode, &snap_size);
6791d3576fdSSage Weil 	if (!snapc) {
6801d3576fdSSage Weil 		/* hmm, why does writepages get called when there
6811d3576fdSSage Weil 		   is no dirty data? */
6821d3576fdSSage Weil 		dout(" no snap context with dirty data?\n");
6831d3576fdSSage Weil 		goto out;
6841d3576fdSSage Weil 	}
6851d3576fdSSage Weil 	dout(" oldest snapc is %p seq %lld (%d snaps)\n",
6861d3576fdSSage Weil 	     snapc, snapc->seq, snapc->num_snaps);
6871d3576fdSSage Weil 	if (last_snapc && snapc != last_snapc) {
6881d3576fdSSage Weil 		/* if we switched to a newer snapc, restart our scan at the
6891d3576fdSSage Weil 		 * start of the original file range. */
6901d3576fdSSage Weil 		dout("  snapc differs from last pass, restarting at %lu\n",
6911d3576fdSSage Weil 		     index);
6921d3576fdSSage Weil 		index = start;
6931d3576fdSSage Weil 	}
6941d3576fdSSage Weil 	last_snapc = snapc;
6951d3576fdSSage Weil 
6961d3576fdSSage Weil 	while (!done && index <= end) {
6971d3576fdSSage Weil 		unsigned i;
6981d3576fdSSage Weil 		int first;
6991d3576fdSSage Weil 		pgoff_t next;
7001d3576fdSSage Weil 		int pvec_pages, locked_pages;
7011d3576fdSSage Weil 		struct page *page;
7021d3576fdSSage Weil 		int want;
7031d3576fdSSage Weil 		u64 offset, len;
7041d3576fdSSage Weil 		struct ceph_osd_request_head *reqhead;
7051d3576fdSSage Weil 		struct ceph_osd_op *op;
7062baba250SYehuda Sadeh 		long writeback_stat;
7071d3576fdSSage Weil 
7081d3576fdSSage Weil 		next = 0;
7091d3576fdSSage Weil 		locked_pages = 0;
7101d3576fdSSage Weil 		max_pages = max_pages_ever;
7111d3576fdSSage Weil 
7121d3576fdSSage Weil get_more_pages:
7131d3576fdSSage Weil 		first = -1;
7141d3576fdSSage Weil 		want = min(end - index,
7151d3576fdSSage Weil 			   min((pgoff_t)PAGEVEC_SIZE,
7161d3576fdSSage Weil 			       max_pages - (pgoff_t)locked_pages) - 1)
7171d3576fdSSage Weil 			+ 1;
7181d3576fdSSage Weil 		pvec_pages = pagevec_lookup_tag(&pvec, mapping, &index,
7191d3576fdSSage Weil 						PAGECACHE_TAG_DIRTY,
7201d3576fdSSage Weil 						want);
7211d3576fdSSage Weil 		dout("pagevec_lookup_tag got %d\n", pvec_pages);
7221d3576fdSSage Weil 		if (!pvec_pages && !locked_pages)
7231d3576fdSSage Weil 			break;
7241d3576fdSSage Weil 		for (i = 0; i < pvec_pages && locked_pages < max_pages; i++) {
7251d3576fdSSage Weil 			page = pvec.pages[i];
7261d3576fdSSage Weil 			dout("? %p idx %lu\n", page, page->index);
7271d3576fdSSage Weil 			if (locked_pages == 0)
7281d3576fdSSage Weil 				lock_page(page);  /* first page */
7291d3576fdSSage Weil 			else if (!trylock_page(page))
7301d3576fdSSage Weil 				break;
7311d3576fdSSage Weil 
7321d3576fdSSage Weil 			/* only dirty pages, or our accounting breaks */
7331d3576fdSSage Weil 			if (unlikely(!PageDirty(page)) ||
7341d3576fdSSage Weil 			    unlikely(page->mapping != mapping)) {
7351d3576fdSSage Weil 				dout("!dirty or !mapping %p\n", page);
7361d3576fdSSage Weil 				unlock_page(page);
7371d3576fdSSage Weil 				break;
7381d3576fdSSage Weil 			}
7391d3576fdSSage Weil 			if (!wbc->range_cyclic && page->index > end) {
7401d3576fdSSage Weil 				dout("end of range %p\n", page);
7411d3576fdSSage Weil 				done = 1;
7421d3576fdSSage Weil 				unlock_page(page);
7431d3576fdSSage Weil 				break;
7441d3576fdSSage Weil 			}
7451d3576fdSSage Weil 			if (next && (page->index != next)) {
7461d3576fdSSage Weil 				dout("not consecutive %p\n", page);
7471d3576fdSSage Weil 				unlock_page(page);
7481d3576fdSSage Weil 				break;
7491d3576fdSSage Weil 			}
7501d3576fdSSage Weil 			if (wbc->sync_mode != WB_SYNC_NONE) {
7511d3576fdSSage Weil 				dout("waiting on writeback %p\n", page);
7521d3576fdSSage Weil 				wait_on_page_writeback(page);
7531d3576fdSSage Weil 			}
7541d3576fdSSage Weil 			if ((snap_size && page_offset(page) > snap_size) ||
7551d3576fdSSage Weil 			    (!snap_size &&
7561d3576fdSSage Weil 			     page_offset(page) > i_size_read(inode))) {
7571d3576fdSSage Weil 				dout("%p page eof %llu\n", page, snap_size ?
7581d3576fdSSage Weil 				     snap_size : i_size_read(inode));
7591d3576fdSSage Weil 				done = 1;
7601d3576fdSSage Weil 				unlock_page(page);
7611d3576fdSSage Weil 				break;
7621d3576fdSSage Weil 			}
7631d3576fdSSage Weil 			if (PageWriteback(page)) {
7641d3576fdSSage Weil 				dout("%p under writeback\n", page);
7651d3576fdSSage Weil 				unlock_page(page);
7661d3576fdSSage Weil 				break;
7671d3576fdSSage Weil 			}
7681d3576fdSSage Weil 
7691d3576fdSSage Weil 			/* only if matching snap context */
7701d3576fdSSage Weil 			if (snapc != (void *)page->private) {
7711d3576fdSSage Weil 				dout("page snapc %p != oldest %p\n",
7721d3576fdSSage Weil 				     (void *)page->private, snapc);
7731d3576fdSSage Weil 				unlock_page(page);
7741d3576fdSSage Weil 				if (!locked_pages)
7751d3576fdSSage Weil 					continue; /* keep looking for snap */
7761d3576fdSSage Weil 				break;
7771d3576fdSSage Weil 			}
7781d3576fdSSage Weil 
7791d3576fdSSage Weil 			if (!clear_page_dirty_for_io(page)) {
7801d3576fdSSage Weil 				dout("%p !clear_page_dirty_for_io\n", page);
7811d3576fdSSage Weil 				unlock_page(page);
7821d3576fdSSage Weil 				break;
7831d3576fdSSage Weil 			}
7841d3576fdSSage Weil 
7851d3576fdSSage Weil 			/* ok */
7861d3576fdSSage Weil 			if (locked_pages == 0) {
7871d3576fdSSage Weil 				/* prepare async write request */
7881d3576fdSSage Weil 				offset = page->index << PAGE_CACHE_SHIFT;
7891d3576fdSSage Weil 				len = wsize;
7901d3576fdSSage Weil 				req = ceph_osdc_new_request(&client->osdc,
7911d3576fdSSage Weil 					    &ci->i_layout,
7921d3576fdSSage Weil 					    ceph_vino(inode),
7931d3576fdSSage Weil 					    offset, &len,
7941d3576fdSSage Weil 					    CEPH_OSD_OP_WRITE,
7951d3576fdSSage Weil 					    CEPH_OSD_FLAG_WRITE |
7961d3576fdSSage Weil 						    CEPH_OSD_FLAG_ONDISK,
7971d3576fdSSage Weil 					    snapc, do_sync,
7981d3576fdSSage Weil 					    ci->i_truncate_seq,
7991d3576fdSSage Weil 					    ci->i_truncate_size,
8001d3576fdSSage Weil 					    &inode->i_mtime, true, 1);
8011d3576fdSSage Weil 				max_pages = req->r_num_pages;
8021d3576fdSSage Weil 
8031d3576fdSSage Weil 				alloc_page_vec(client, req);
8041d3576fdSSage Weil 				req->r_callback = writepages_finish;
8051d3576fdSSage Weil 				req->r_inode = inode;
8061d3576fdSSage Weil 				req->r_wbc = wbc;
8071d3576fdSSage Weil 			}
8081d3576fdSSage Weil 
8091d3576fdSSage Weil 			/* note position of first page in pvec */
8101d3576fdSSage Weil 			if (first < 0)
8111d3576fdSSage Weil 				first = i;
8121d3576fdSSage Weil 			dout("%p will write page %p idx %lu\n",
8131d3576fdSSage Weil 			     inode, page, page->index);
8142baba250SYehuda Sadeh 
8152baba250SYehuda Sadeh 			writeback_stat = atomic_long_inc_return(&client->writeback_count);
8162baba250SYehuda Sadeh 			if (writeback_stat > CONGESTION_ON_THRESH(client->mount_args->congestion_kb)) {
8172baba250SYehuda Sadeh 				set_bdi_congested(&client->backing_dev_info, BLK_RW_ASYNC);
8182baba250SYehuda Sadeh 			}
8192baba250SYehuda Sadeh 
8201d3576fdSSage Weil 			set_page_writeback(page);
8211d3576fdSSage Weil 			req->r_pages[locked_pages] = page;
8221d3576fdSSage Weil 			locked_pages++;
8231d3576fdSSage Weil 			next = page->index + 1;
8241d3576fdSSage Weil 		}
8251d3576fdSSage Weil 
8261d3576fdSSage Weil 		/* did we get anything? */
8271d3576fdSSage Weil 		if (!locked_pages)
8281d3576fdSSage Weil 			goto release_pvec_pages;
8291d3576fdSSage Weil 		if (i) {
8301d3576fdSSage Weil 			int j;
8311d3576fdSSage Weil 			BUG_ON(!locked_pages || first < 0);
8321d3576fdSSage Weil 
8331d3576fdSSage Weil 			if (pvec_pages && i == pvec_pages &&
8341d3576fdSSage Weil 			    locked_pages < max_pages) {
8351d3576fdSSage Weil 				dout("reached end pvec, trying for more\n");
8361d3576fdSSage Weil 				pagevec_reinit(&pvec);
8371d3576fdSSage Weil 				goto get_more_pages;
8381d3576fdSSage Weil 			}
8391d3576fdSSage Weil 
8401d3576fdSSage Weil 			/* shift unused pages over in the pvec...  we
8411d3576fdSSage Weil 			 * will need to release them below. */
8421d3576fdSSage Weil 			for (j = i; j < pvec_pages; j++) {
8431d3576fdSSage Weil 				dout(" pvec leftover page %p\n",
8441d3576fdSSage Weil 				     pvec.pages[j]);
8451d3576fdSSage Weil 				pvec.pages[j-i+first] = pvec.pages[j];
8461d3576fdSSage Weil 			}
8471d3576fdSSage Weil 			pvec.nr -= i-first;
8481d3576fdSSage Weil 		}
8491d3576fdSSage Weil 
8501d3576fdSSage Weil 		/* submit the write */
8511d3576fdSSage Weil 		offset = req->r_pages[0]->index << PAGE_CACHE_SHIFT;
8521d3576fdSSage Weil 		len = min((snap_size ? snap_size : i_size_read(inode)) - offset,
8531d3576fdSSage Weil 			  (u64)locked_pages << PAGE_CACHE_SHIFT);
8541d3576fdSSage Weil 		dout("writepages got %d pages at %llu~%llu\n",
8551d3576fdSSage Weil 		     locked_pages, offset, len);
8561d3576fdSSage Weil 
8571d3576fdSSage Weil 		/* revise final length, page count */
8581d3576fdSSage Weil 		req->r_num_pages = locked_pages;
8591d3576fdSSage Weil 		reqhead = req->r_request->front.iov_base;
8601d3576fdSSage Weil 		op = (void *)(reqhead + 1);
8611d3576fdSSage Weil 		op->extent.length = cpu_to_le64(len);
8621d3576fdSSage Weil 		op->payload_len = cpu_to_le32(len);
8631d3576fdSSage Weil 		req->r_request->hdr.data_len = cpu_to_le32(len);
8641d3576fdSSage Weil 
8651d3576fdSSage Weil 		ceph_osdc_start_request(&client->osdc, req, true);
8661d3576fdSSage Weil 		req = NULL;
8671d3576fdSSage Weil 
8681d3576fdSSage Weil 		/* continue? */
8691d3576fdSSage Weil 		index = next;
8701d3576fdSSage Weil 		wbc->nr_to_write -= locked_pages;
8711d3576fdSSage Weil 		if (wbc->nr_to_write <= 0)
8721d3576fdSSage Weil 			done = 1;
8731d3576fdSSage Weil 
8741d3576fdSSage Weil release_pvec_pages:
8751d3576fdSSage Weil 		dout("pagevec_release on %d pages (%p)\n", (int)pvec.nr,
8761d3576fdSSage Weil 		     pvec.nr ? pvec.pages[0] : NULL);
8771d3576fdSSage Weil 		pagevec_release(&pvec);
8781d3576fdSSage Weil 
8791d3576fdSSage Weil 		if (locked_pages && !done)
8801d3576fdSSage Weil 			goto retry;
8811d3576fdSSage Weil 	}
8821d3576fdSSage Weil 
8831d3576fdSSage Weil 	if (should_loop && !done) {
8841d3576fdSSage Weil 		/* more to do; loop back to beginning of file */
8851d3576fdSSage Weil 		dout("writepages looping back to beginning of file\n");
8861d3576fdSSage Weil 		should_loop = 0;
8871d3576fdSSage Weil 		index = 0;
8881d3576fdSSage Weil 		goto retry;
8891d3576fdSSage Weil 	}
8901d3576fdSSage Weil 
8911d3576fdSSage Weil 	if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0))
8921d3576fdSSage Weil 		mapping->writeback_index = index;
8931d3576fdSSage Weil 
8941d3576fdSSage Weil out:
8951d3576fdSSage Weil 	if (req)
8961d3576fdSSage Weil 		ceph_osdc_put_request(req);
8971d3576fdSSage Weil 	if (rc > 0)
8981d3576fdSSage Weil 		rc = 0;  /* vfs expects us to return 0 */
8991d3576fdSSage Weil 	ceph_put_snap_context(snapc);
9001d3576fdSSage Weil 	dout("writepages done, rc = %d\n", rc);
9011d3576fdSSage Weil out_final:
9021d3576fdSSage Weil 	return rc;
9031d3576fdSSage Weil }
9041d3576fdSSage Weil 
9051d3576fdSSage Weil 
9061d3576fdSSage Weil 
9071d3576fdSSage Weil /*
9081d3576fdSSage Weil  * See if a given @snapc is either writeable, or already written.
9091d3576fdSSage Weil  */
9101d3576fdSSage Weil static int context_is_writeable_or_written(struct inode *inode,
9111d3576fdSSage Weil 					   struct ceph_snap_context *snapc)
9121d3576fdSSage Weil {
9131d3576fdSSage Weil 	struct ceph_snap_context *oldest = get_oldest_context(inode, NULL);
9141d3576fdSSage Weil 	return !oldest || snapc->seq <= oldest->seq;
9151d3576fdSSage Weil }
9161d3576fdSSage Weil 
9171d3576fdSSage Weil /*
9181d3576fdSSage Weil  * We are only allowed to write into/dirty the page if the page is
9191d3576fdSSage Weil  * clean, or already dirty within the same snap context.
9201d3576fdSSage Weil  */
9214af6b225SYehuda Sadeh static int ceph_update_writeable_page(struct file *file,
9224af6b225SYehuda Sadeh 			    loff_t pos, unsigned len,
9234af6b225SYehuda Sadeh 			    struct page *page)
9241d3576fdSSage Weil {
9251d3576fdSSage Weil 	struct inode *inode = file->f_dentry->d_inode;
9261d3576fdSSage Weil 	struct ceph_inode_info *ci = ceph_inode(inode);
9271d3576fdSSage Weil 	struct ceph_mds_client *mdsc = &ceph_inode_to_client(inode)->mdsc;
9281d3576fdSSage Weil 	loff_t page_off = pos & PAGE_CACHE_MASK;
9291d3576fdSSage Weil 	int pos_in_page = pos & ~PAGE_CACHE_MASK;
9301d3576fdSSage Weil 	int end_in_page = pos_in_page + len;
9311d3576fdSSage Weil 	loff_t i_size;
9321d3576fdSSage Weil 	struct ceph_snap_context *snapc;
9331d3576fdSSage Weil 	int r;
9341d3576fdSSage Weil 
9351d3576fdSSage Weil retry_locked:
9361d3576fdSSage Weil 	/* writepages currently holds page lock, but if we change that later, */
9371d3576fdSSage Weil 	wait_on_page_writeback(page);
9381d3576fdSSage Weil 
9391d3576fdSSage Weil 	/* check snap context */
9401d3576fdSSage Weil 	BUG_ON(!ci->i_snap_realm);
9411d3576fdSSage Weil 	down_read(&mdsc->snap_rwsem);
9421d3576fdSSage Weil 	BUG_ON(!ci->i_snap_realm->cached_context);
9431d3576fdSSage Weil 	if (page->private &&
9441d3576fdSSage Weil 	    (void *)page->private != ci->i_snap_realm->cached_context) {
9451d3576fdSSage Weil 		/*
9461d3576fdSSage Weil 		 * this page is already dirty in another (older) snap
9471d3576fdSSage Weil 		 * context!  is it writeable now?
9481d3576fdSSage Weil 		 */
9491d3576fdSSage Weil 		snapc = get_oldest_context(inode, NULL);
9501d3576fdSSage Weil 		up_read(&mdsc->snap_rwsem);
9511d3576fdSSage Weil 
9521d3576fdSSage Weil 		if (snapc != (void *)page->private) {
9531d3576fdSSage Weil 			dout(" page %p snapc %p not current or oldest\n",
9541d3576fdSSage Weil 			     page, (void *)page->private);
9551d3576fdSSage Weil 			/*
9561d3576fdSSage Weil 			 * queue for writeback, and wait for snapc to
9571d3576fdSSage Weil 			 * be writeable or written
9581d3576fdSSage Weil 			 */
9591d3576fdSSage Weil 			snapc = ceph_get_snap_context((void *)page->private);
9601d3576fdSSage Weil 			unlock_page(page);
9613c6f6b79SSage Weil 			ceph_queue_writeback(inode);
9621d3576fdSSage Weil 			wait_event_interruptible(ci->i_cap_wq,
9631d3576fdSSage Weil 			       context_is_writeable_or_written(inode, snapc));
9641d3576fdSSage Weil 			ceph_put_snap_context(snapc);
9654af6b225SYehuda Sadeh 			return -EAGAIN;
9661d3576fdSSage Weil 		}
9671d3576fdSSage Weil 
9681d3576fdSSage Weil 		/* yay, writeable, do it now (without dropping page lock) */
9691d3576fdSSage Weil 		dout(" page %p snapc %p not current, but oldest\n",
9701d3576fdSSage Weil 		     page, snapc);
9711d3576fdSSage Weil 		if (!clear_page_dirty_for_io(page))
9721d3576fdSSage Weil 			goto retry_locked;
9731d3576fdSSage Weil 		r = writepage_nounlock(page, NULL);
9741d3576fdSSage Weil 		if (r < 0)
9751d3576fdSSage Weil 			goto fail_nosnap;
9761d3576fdSSage Weil 		goto retry_locked;
9771d3576fdSSage Weil 	}
9781d3576fdSSage Weil 
9791d3576fdSSage Weil 	if (PageUptodate(page)) {
9801d3576fdSSage Weil 		dout(" page %p already uptodate\n", page);
9811d3576fdSSage Weil 		return 0;
9821d3576fdSSage Weil 	}
9831d3576fdSSage Weil 
9841d3576fdSSage Weil 	/* full page? */
9851d3576fdSSage Weil 	if (pos_in_page == 0 && len == PAGE_CACHE_SIZE)
9861d3576fdSSage Weil 		return 0;
9871d3576fdSSage Weil 
9881d3576fdSSage Weil 	/* past end of file? */
9891d3576fdSSage Weil 	i_size = inode->i_size;   /* caller holds i_mutex */
9901d3576fdSSage Weil 
9911d3576fdSSage Weil 	if (i_size + len > inode->i_sb->s_maxbytes) {
9921d3576fdSSage Weil 		/* file is too big */
9931d3576fdSSage Weil 		r = -EINVAL;
9941d3576fdSSage Weil 		goto fail;
9951d3576fdSSage Weil 	}
9961d3576fdSSage Weil 
9971d3576fdSSage Weil 	if (page_off >= i_size ||
9981d3576fdSSage Weil 	    (pos_in_page == 0 && (pos+len) >= i_size &&
9991d3576fdSSage Weil 	     end_in_page - pos_in_page != PAGE_CACHE_SIZE)) {
10001d3576fdSSage Weil 		dout(" zeroing %p 0 - %d and %d - %d\n",
10011d3576fdSSage Weil 		     page, pos_in_page, end_in_page, (int)PAGE_CACHE_SIZE);
10021d3576fdSSage Weil 		zero_user_segments(page,
10031d3576fdSSage Weil 				   0, pos_in_page,
10041d3576fdSSage Weil 				   end_in_page, PAGE_CACHE_SIZE);
10051d3576fdSSage Weil 		return 0;
10061d3576fdSSage Weil 	}
10071d3576fdSSage Weil 
10081d3576fdSSage Weil 	/* we need to read it. */
10091d3576fdSSage Weil 	up_read(&mdsc->snap_rwsem);
10101d3576fdSSage Weil 	r = readpage_nounlock(file, page);
10111d3576fdSSage Weil 	if (r < 0)
10121d3576fdSSage Weil 		goto fail_nosnap;
10131d3576fdSSage Weil 	goto retry_locked;
10141d3576fdSSage Weil 
10151d3576fdSSage Weil fail:
10161d3576fdSSage Weil 	up_read(&mdsc->snap_rwsem);
10171d3576fdSSage Weil fail_nosnap:
10181d3576fdSSage Weil 	unlock_page(page);
10191d3576fdSSage Weil 	return r;
10201d3576fdSSage Weil }
10211d3576fdSSage Weil 
10221d3576fdSSage Weil /*
10234af6b225SYehuda Sadeh  * We are only allowed to write into/dirty the page if the page is
10244af6b225SYehuda Sadeh  * clean, or already dirty within the same snap context.
10254af6b225SYehuda Sadeh  */
10264af6b225SYehuda Sadeh static int ceph_write_begin(struct file *file, struct address_space *mapping,
10274af6b225SYehuda Sadeh 			    loff_t pos, unsigned len, unsigned flags,
10284af6b225SYehuda Sadeh 			    struct page **pagep, void **fsdata)
10294af6b225SYehuda Sadeh {
10304af6b225SYehuda Sadeh 	struct inode *inode = file->f_dentry->d_inode;
10314af6b225SYehuda Sadeh 	struct page *page;
10324af6b225SYehuda Sadeh 	pgoff_t index = pos >> PAGE_CACHE_SHIFT;
10334af6b225SYehuda Sadeh 	int r;
10344af6b225SYehuda Sadeh 
10354af6b225SYehuda Sadeh 	do {
10364af6b225SYehuda Sadeh 		/* get a page*/
10374af6b225SYehuda Sadeh 		page = grab_cache_page_write_begin(mapping, index, 0);
10384af6b225SYehuda Sadeh 		if (!page)
10394af6b225SYehuda Sadeh 			return -ENOMEM;
10404af6b225SYehuda Sadeh 		*pagep = page;
10414af6b225SYehuda Sadeh 
10424af6b225SYehuda Sadeh 		dout("write_begin file %p inode %p page %p %d~%d\n", file,
10434af6b225SYehuda Sadeh 	     	inode, page, (int)pos, (int)len);
10444af6b225SYehuda Sadeh 
10454af6b225SYehuda Sadeh 		r = ceph_update_writeable_page(file, pos, len, page);
10464af6b225SYehuda Sadeh 	} while (r == -EAGAIN);
10474af6b225SYehuda Sadeh 
10484af6b225SYehuda Sadeh 	return r;
10494af6b225SYehuda Sadeh }
10504af6b225SYehuda Sadeh 
10514af6b225SYehuda Sadeh /*
10521d3576fdSSage Weil  * we don't do anything in here that simple_write_end doesn't do
10531d3576fdSSage Weil  * except adjust dirty page accounting and drop read lock on
10541d3576fdSSage Weil  * mdsc->snap_rwsem.
10551d3576fdSSage Weil  */
10561d3576fdSSage Weil static int ceph_write_end(struct file *file, struct address_space *mapping,
10571d3576fdSSage Weil 			  loff_t pos, unsigned len, unsigned copied,
10581d3576fdSSage Weil 			  struct page *page, void *fsdata)
10591d3576fdSSage Weil {
10601d3576fdSSage Weil 	struct inode *inode = file->f_dentry->d_inode;
10612baba250SYehuda Sadeh 	struct ceph_client *client = ceph_inode_to_client(inode);
10622baba250SYehuda Sadeh 	struct ceph_mds_client *mdsc = &client->mdsc;
10631d3576fdSSage Weil 	unsigned from = pos & (PAGE_CACHE_SIZE - 1);
10641d3576fdSSage Weil 	int check_cap = 0;
10651d3576fdSSage Weil 
10661d3576fdSSage Weil 	dout("write_end file %p inode %p page %p %d~%d (%d)\n", file,
10671d3576fdSSage Weil 	     inode, page, (int)pos, (int)copied, (int)len);
10681d3576fdSSage Weil 
10691d3576fdSSage Weil 	/* zero the stale part of the page if we did a short copy */
10701d3576fdSSage Weil 	if (copied < len)
10711d3576fdSSage Weil 		zero_user_segment(page, from+copied, len);
10721d3576fdSSage Weil 
10731d3576fdSSage Weil 	/* did file size increase? */
10741d3576fdSSage Weil 	/* (no need for i_size_read(); we caller holds i_mutex */
10751d3576fdSSage Weil 	if (pos+copied > inode->i_size)
10761d3576fdSSage Weil 		check_cap = ceph_inode_set_size(inode, pos+copied);
10771d3576fdSSage Weil 
10781d3576fdSSage Weil 	if (!PageUptodate(page))
10791d3576fdSSage Weil 		SetPageUptodate(page);
10801d3576fdSSage Weil 
10811d3576fdSSage Weil 	set_page_dirty(page);
10821d3576fdSSage Weil 
10831d3576fdSSage Weil 	unlock_page(page);
10841d3576fdSSage Weil 	up_read(&mdsc->snap_rwsem);
10851d3576fdSSage Weil 	page_cache_release(page);
10861d3576fdSSage Weil 
10871d3576fdSSage Weil 	if (check_cap)
10881d3576fdSSage Weil 		ceph_check_caps(ceph_inode(inode), CHECK_CAPS_AUTHONLY, NULL);
10891d3576fdSSage Weil 
10901d3576fdSSage Weil 	return copied;
10911d3576fdSSage Weil }
10921d3576fdSSage Weil 
10931d3576fdSSage Weil /*
10941d3576fdSSage Weil  * we set .direct_IO to indicate direct io is supported, but since we
10951d3576fdSSage Weil  * intercept O_DIRECT reads and writes early, this function should
10961d3576fdSSage Weil  * never get called.
10971d3576fdSSage Weil  */
10981d3576fdSSage Weil static ssize_t ceph_direct_io(int rw, struct kiocb *iocb,
10991d3576fdSSage Weil 			      const struct iovec *iov,
11001d3576fdSSage Weil 			      loff_t pos, unsigned long nr_segs)
11011d3576fdSSage Weil {
11021d3576fdSSage Weil 	WARN_ON(1);
11031d3576fdSSage Weil 	return -EINVAL;
11041d3576fdSSage Weil }
11051d3576fdSSage Weil 
11061d3576fdSSage Weil const struct address_space_operations ceph_aops = {
11071d3576fdSSage Weil 	.readpage = ceph_readpage,
11081d3576fdSSage Weil 	.readpages = ceph_readpages,
11091d3576fdSSage Weil 	.writepage = ceph_writepage,
11101d3576fdSSage Weil 	.writepages = ceph_writepages_start,
11111d3576fdSSage Weil 	.write_begin = ceph_write_begin,
11121d3576fdSSage Weil 	.write_end = ceph_write_end,
11131d3576fdSSage Weil 	.set_page_dirty = ceph_set_page_dirty,
11141d3576fdSSage Weil 	.invalidatepage = ceph_invalidatepage,
11151d3576fdSSage Weil 	.releasepage = ceph_releasepage,
11161d3576fdSSage Weil 	.direct_IO = ceph_direct_io,
11171d3576fdSSage Weil };
11181d3576fdSSage Weil 
11191d3576fdSSage Weil 
11201d3576fdSSage Weil /*
11211d3576fdSSage Weil  * vm ops
11221d3576fdSSage Weil  */
11231d3576fdSSage Weil 
11241d3576fdSSage Weil /*
11251d3576fdSSage Weil  * Reuse write_begin here for simplicity.
11261d3576fdSSage Weil  */
11271d3576fdSSage Weil static int ceph_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
11281d3576fdSSage Weil {
11291d3576fdSSage Weil 	struct inode *inode = vma->vm_file->f_dentry->d_inode;
11301d3576fdSSage Weil 	struct page *page = vmf->page;
11311d3576fdSSage Weil 	struct ceph_mds_client *mdsc = &ceph_inode_to_client(inode)->mdsc;
11321d3576fdSSage Weil 	loff_t off = page->index << PAGE_CACHE_SHIFT;
11331d3576fdSSage Weil 	loff_t size, len;
11341d3576fdSSage Weil 	int ret;
11351d3576fdSSage Weil 
11361d3576fdSSage Weil 	size = i_size_read(inode);
11371d3576fdSSage Weil 	if (off + PAGE_CACHE_SIZE <= size)
11381d3576fdSSage Weil 		len = PAGE_CACHE_SIZE;
11391d3576fdSSage Weil 	else
11401d3576fdSSage Weil 		len = size & ~PAGE_CACHE_MASK;
11411d3576fdSSage Weil 
11421d3576fdSSage Weil 	dout("page_mkwrite %p %llu~%llu page %p idx %lu\n", inode,
11431d3576fdSSage Weil 	     off, len, page, page->index);
11444af6b225SYehuda Sadeh 
11454af6b225SYehuda Sadeh 	lock_page(page);
11464af6b225SYehuda Sadeh 
11474af6b225SYehuda Sadeh 	ret = VM_FAULT_NOPAGE;
11484af6b225SYehuda Sadeh 	if ((off > size) ||
11494af6b225SYehuda Sadeh 	    (page->mapping != inode->i_mapping))
11504af6b225SYehuda Sadeh 		goto out;
11514af6b225SYehuda Sadeh 
11524af6b225SYehuda Sadeh 	ret = ceph_update_writeable_page(vma->vm_file, off, len, page);
11534af6b225SYehuda Sadeh 	if (ret == 0) {
11544af6b225SYehuda Sadeh 		/* success.  we'll keep the page locked. */
11551d3576fdSSage Weil 		set_page_dirty(page);
11561d3576fdSSage Weil 		up_read(&mdsc->snap_rwsem);
11571d3576fdSSage Weil 		ret = VM_FAULT_LOCKED;
11581d3576fdSSage Weil 	} else {
11594af6b225SYehuda Sadeh 		if (ret == -ENOMEM)
11604af6b225SYehuda Sadeh 			ret = VM_FAULT_OOM;
11614af6b225SYehuda Sadeh 		else
11621d3576fdSSage Weil 			ret = VM_FAULT_SIGBUS;
11631d3576fdSSage Weil 	}
11644af6b225SYehuda Sadeh out:
11651d3576fdSSage Weil 	dout("page_mkwrite %p %llu~%llu = %d\n", inode, off, len, ret);
11664af6b225SYehuda Sadeh 	if (ret != VM_FAULT_LOCKED)
11674af6b225SYehuda Sadeh 		unlock_page(page);
11681d3576fdSSage Weil 	return ret;
11691d3576fdSSage Weil }
11701d3576fdSSage Weil 
11711d3576fdSSage Weil static struct vm_operations_struct ceph_vmops = {
11721d3576fdSSage Weil 	.fault		= filemap_fault,
11731d3576fdSSage Weil 	.page_mkwrite	= ceph_page_mkwrite,
11741d3576fdSSage Weil };
11751d3576fdSSage Weil 
11761d3576fdSSage Weil int ceph_mmap(struct file *file, struct vm_area_struct *vma)
11771d3576fdSSage Weil {
11781d3576fdSSage Weil 	struct address_space *mapping = file->f_mapping;
11791d3576fdSSage Weil 
11801d3576fdSSage Weil 	if (!mapping->a_ops->readpage)
11811d3576fdSSage Weil 		return -ENOEXEC;
11821d3576fdSSage Weil 	file_accessed(file);
11831d3576fdSSage Weil 	vma->vm_ops = &ceph_vmops;
11841d3576fdSSage Weil 	vma->vm_flags |= VM_CAN_NONLINEAR;
11851d3576fdSSage Weil 	return 0;
11861d3576fdSSage Weil }
1187