#include <linux/ceph/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/slab.h> #include <linux/pagevec.h> #include <linux/task_io_accounting_ops.h> #include "super.h" #include "mds_client.h" #include <linux/ceph/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 absence 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. */ #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)) /* * 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_head_snapc == NULL) ci->i_head_snapc = ceph_get_snap_context(snapc); ++ci->i_wrbuffer_ref_head; if (ci->i_wrbuffer_ref == 0) ihold(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)); account_page_dirtied(page, page->mapping); 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) { struct inode *inode; 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); inode = page->mapping->host; /* * 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)->client->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, 0); 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)->client->osdc; int rc = 0; struct page **pages; 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, 0); if (rc == -ENOENT) rc = 0; if (rc < 0) goto out; 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_lru(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); page_cache_release(page); } 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. */ 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; spin_lock(&inode->i_lock); 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_wrbuffer_ref_head) { snapc = ceph_get_snap_context(ci->i_head_snapc); dout(" head snapc %p has %d dirty pages\n", snapc, ci->i_wrbuffer_ref_head); } 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; struct ceph_fs_client *fsc; 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, *oldest; u64 snap_size = 0; long writeback_stat; 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); fsc = ceph_inode_to_client(inode); osdc = &fsc->client->osdc; /* 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; } oldest = get_oldest_context(inode, &snap_size); if (snapc->seq > oldest->seq) { 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); ceph_put_snap_context(oldest); goto out; } ceph_put_snap_context(oldest); /* 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 snapc %p\n", inode, page, page->index, page_off, len, snapc); writeback_stat = atomic_long_inc_return(&fsc->writeback_count); if (writeback_stat > CONGESTION_ON_THRESH(fsc->mount_options->congestion_kb)) set_bdi_congested(&fsc->backing_dev_info, BLK_RW_ASYNC); 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); /* page's reference */ out: return err; } static int ceph_writepage(struct page *page, struct writeback_control *wbc) { int err; struct inode *inode = page->mapping->host; BUG_ON(!inode); ihold(inode); err = writepage_nounlock(page, wbc); unlock_page(page); iput(inode); 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; __s32 rc = -EIO; u64 bytes = 0; struct ceph_fs_client *fsc = ceph_inode_to_client(inode); long writeback_stat; unsigned issued = ceph_caps_issued(ci); /* 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) { /* * 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; } 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)); writeback_stat = atomic_long_dec_return(&fsc->writeback_count); if (writeback_stat < CONGESTION_OFF_THRESH(fsc->mount_options->congestion_kb)) clear_bdi_congested(&fsc->backing_dev_info, BLK_RW_ASYNC); ceph_put_snap_context((void *)page->private); page->private = 0; ClearPagePrivate(page); dout("unlocking %d %p\n", i, page); end_page_writeback(page); /* * 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|CEPH_CAP_FILE_LAZYIO)) == 0) generic_error_remove_page(inode->i_mapping, page); 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_sb_to_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_fs_client *fsc, 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(fsc->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 ceph_inode_info *ci = ceph_inode(inode); struct ceph_fs_client *fsc; 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, *pgsnapc; 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")); fsc = ceph_inode_to_client(inode); if (fsc->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! */ } if (fsc->mount_options->wsize && fsc->mount_options->wsize < wsize) wsize = fsc->mount_options->wsize; if (wsize < PAGE_CACHE_SIZE) wsize = PAGE_CACHE_SIZE; max_pages_ever = wsize >> PAGE_CACHE_SHIFT; pagevec_init(&pvec, 0); /* 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; long writeback_stat; 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 */ pgsnapc = (void *)page->private; if (pgsnapc->seq > snapc->seq) { dout("page snapc %p %lld > oldest %p %lld\n", pgsnapc, pgsnapc->seq, snapc, snapc->seq); 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 = (unsigned long long)page->index << PAGE_CACHE_SHIFT; len = wsize; req = ceph_osdc_new_request(&fsc->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, 0); if (!req) { rc = -ENOMEM; unlock_page(page); break; } max_pages = req->r_num_pages; alloc_page_vec(fsc, req); req->r_callback = writepages_finish; req->r_inode = inode; } /* 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); writeback_stat = atomic_long_inc_return(&fsc->writeback_count); if (writeback_stat > CONGESTION_ON_THRESH( fsc->mount_options->congestion_kb)) { set_bdi_congested(&fsc->backing_dev_info, BLK_RW_ASYNC); } 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); rc = ceph_osdc_start_request(&fsc->client->osdc, req, true); BUG_ON(rc); 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); ceph_put_snap_context(snapc); dout("writepages done, rc = %d\n", rc); 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); int ret = !oldest || snapc->seq <= oldest->seq; ceph_put_snap_context(oldest); return ret; } /* * We are only allowed to write into/dirty the page if the page is * clean, or already dirty within the same snap context. * * called with page locked. * return success with page locked, * or any failure (incl -EAGAIN) with page unlocked. */ static int ceph_update_writeable_page(struct file *file, loff_t pos, unsigned len, struct page *page) { 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; int r; struct ceph_snap_context *snapc, *oldest; 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); snapc = (void *)page->private; if (snapc && snapc != ci->i_head_snapc) { /* * this page is already dirty in another (older) snap * context! is it writeable now? */ oldest = get_oldest_context(inode, NULL); up_read(&mdsc->snap_rwsem); if (snapc->seq > oldest->seq) { ceph_put_snap_context(oldest); dout(" page %p snapc %p not current or oldest\n", page, snapc); /* * queue for writeback, and wait for snapc to * be writeable or written */ snapc = ceph_get_snap_context(snapc); unlock_page(page); ceph_queue_writeback(inode); r = wait_event_interruptible(ci->i_cap_wq, context_is_writeable_or_written(inode, snapc)); ceph_put_snap_context(snapc); if (r == -ERESTARTSYS) return r; return -EAGAIN; } ceph_put_snap_context(oldest); /* 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; } /* * 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 { /* get a page */ 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; } /* * 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; struct ceph_fs_client *fsc = ceph_inode_to_client(inode); struct ceph_mds_client *mdsc = fsc->mdsc; 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); 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. */ set_page_dirty(page); up_read(&mdsc->snap_rwsem); ret = VM_FAULT_LOCKED; } else { if (ret == -ENOMEM) ret = VM_FAULT_OOM; else ret = VM_FAULT_SIGBUS; } out: dout("page_mkwrite %p %llu~%llu = %d\n", inode, off, len, ret); if (ret != VM_FAULT_LOCKED) unlock_page(page); 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; }