diff options
Diffstat (limited to 'fs/ceph/addr.c')
| -rw-r--r-- | fs/ceph/addr.c | 1193 |
1 files changed, 1193 insertions, 0 deletions
diff --git a/fs/ceph/addr.c b/fs/ceph/addr.c new file mode 100644 index 00000000000..4b42c2bb603 --- /dev/null +++ b/fs/ceph/addr.c @@ -0,0 +1,1193 @@ +#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/slab.h> +#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. + */ + +#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_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) +{ + 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)->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. + */ +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_head_snapc) { + 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_client *client; + 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); + client = ceph_inode_to_client(inode); + osdc = &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\n", + inode, page, page->index, page_off, len); + + 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); + + 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); + igrab(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; + struct writeback_control *wbc = req->r_wbc; + __s32 rc = -EIO; + u64 bytes = 0; + struct ceph_client *client = 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(&client->writeback_count); + if (writeback_stat < + CONGESTION_OFF_THRESH(client->mount_args->congestion_kb)) + clear_bdi_congested(&client->backing_dev_info, + BLK_RW_ASYNC); + + if (i >= wrote) { + dout("inode %p skipping page %p\n", inode, page); + wbc->pages_skipped++; + } + 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) == 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_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); + struct ceph_client *client; + 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")); + + 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! */ + } + if (client->mount_args->wsize && client->mount_args->wsize < wsize) + wsize = client->mount_args->wsize; + 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; + 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 = 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); + + 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); + } + + 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); + 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_client *client = ceph_inode_to_client(inode); + struct ceph_mds_client *mdsc = &client->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; +} |