--- /dev/null
+#include "ceph_debug.h"
+
+#include <linux/backing-dev.h>
+#include <linux/fs.h>
+#include <linux/mm.h>
+#include <linux/pagemap.h>
+#include <linux/writeback.h> /* generic_writepages */
+#include <linux/pagevec.h>
+#include <linux/task_io_accounting_ops.h>
+
+#include "super.h"
+#include "osd_client.h"
+
+/*
+ * Ceph address space ops.
+ *
+ * There are a few funny things going on here.
+ *
+ * The page->private field is used to reference a struct
+ * ceph_snap_context for _every_ dirty page. This indicates which
+ * snapshot the page was logically dirtied in, and thus which snap
+ * context needs to be associated with the osd write during writeback.
+ *
+ * Similarly, struct ceph_inode_info maintains a set of counters to
+ * count dirty pages on the inode. In the absense of snapshots,
+ * i_wrbuffer_ref == i_wrbuffer_ref_head == the dirty page count.
+ *
+ * When a snapshot is taken (that is, when the client receives
+ * notification that a snapshot was taken), each inode with caps and
+ * with dirty pages (dirty pages implies there is a cap) gets a new
+ * ceph_cap_snap in the i_cap_snaps list (which is sorted in ascending
+ * order, new snaps go to the tail). The i_wrbuffer_ref_head count is
+ * moved to capsnap->dirty. (Unless a sync write is currently in
+ * progress. In that case, the capsnap is said to be "pending", new
+ * writes cannot start, and the capsnap isn't "finalized" until the
+ * write completes (or fails) and a final size/mtime for the inode for
+ * that snap can be settled upon.) i_wrbuffer_ref_head is reset to 0.
+ *
+ * On writeback, we must submit writes to the osd IN SNAP ORDER. So,
+ * we look for the first capsnap in i_cap_snaps and write out pages in
+ * that snap context _only_. Then we move on to the next capsnap,
+ * eventually reaching the "live" or "head" context (i.e., pages that
+ * are not yet snapped) and are writing the most recently dirtied
+ * pages.
+ *
+ * Invalidate and so forth must take care to ensure the dirty page
+ * accounting is preserved.
+ */
+
+
+/*
+ * 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 = page->mapping->host;
+ 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);
+
+ /*
+ * We can get non-dirty pages here due to races between
+ * set_page_dirty and truncate_complete_page; just spit out a
+ * warning, in case we end up with accounting problems later.
+ */
+ if (!PageDirty(page))
+ pr_err("%p invalidatepage %p page not dirty\n", inode, page);
+
+ if (offset == 0)
+ ClearPageChecked(page);
+
+ ci = ceph_inode(inode);
+ if (offset == 0) {
+ dout("%p invalidatepage %p idx %lu full dirty page %lu\n",
+ inode, page, page->index, offset);
+ ceph_put_wrbuffer_cap_refs(ci, 1, snapc);
+ ceph_put_snap_context(snapc);
+ page->private = 0;
+ ClearPagePrivate(page);
+ } else {
+ dout("%p invalidatepage %p idx %lu partial dirty page\n",
+ inode, page, page->index);
+ }
+}
+
+/* just a sanity check */
+static int ceph_releasepage(struct page *page, gfp_t g)
+{
+ struct inode *inode = page->mapping ? page->mapping->host : NULL;
+ dout("%p releasepage %p idx %lu\n", inode, page, page->index);
+ WARN_ON(PageDirty(page));
+ WARN_ON(page->private);
+ WARN_ON(PagePrivate(page));
+ return 0;
+}
+
+/*
+ * read a single page, without unlocking it.
+ */
+static int readpage_nounlock(struct file *filp, struct page *page)
+{
+ struct inode *inode = filp->f_dentry->d_inode;
+ struct ceph_inode_info *ci = ceph_inode(inode);
+ struct ceph_osd_client *osdc = &ceph_inode_to_client(inode)->osdc;
+ int err = 0;
+ u64 len = PAGE_CACHE_SIZE;
+
+ dout("readpage inode %p file %p page %p index %lu\n",
+ inode, filp, page, page->index);
+ err = ceph_osdc_readpages(osdc, ceph_vino(inode), &ci->i_layout,
+ page->index << PAGE_CACHE_SHIFT, &len,
+ ci->i_truncate_seq, ci->i_truncate_size,
+ &page, 1);
+ if (err == -ENOENT)
+ err = 0;
+ if (err < 0) {
+ SetPageError(page);
+ goto out;
+ } else if (err < PAGE_CACHE_SIZE) {
+ /* zero fill remainder of page */
+ zero_user_segment(page, err, PAGE_CACHE_SIZE);
+ }
+ SetPageUptodate(page);
+
+out:
+ return err < 0 ? err : 0;
+}
+
+static int ceph_readpage(struct file *filp, struct page *page)
+{
+ int r = readpage_nounlock(filp, page);
+ unlock_page(page);
+ return r;
+}
+
+/*
+ * Build a vector of contiguous pages from the provided page list.
+ */
+static struct page **page_vector_from_list(struct list_head *page_list,
+ unsigned *nr_pages)
+{
+ struct page **pages;
+ struct page *page;
+ int next_index, contig_pages = 0;
+
+ /* build page vector */
+ pages = kmalloc(sizeof(*pages) * *nr_pages, GFP_NOFS);
+ if (!pages)
+ return ERR_PTR(-ENOMEM);
+
+ BUG_ON(list_empty(page_list));
+ next_index = list_entry(page_list->prev, struct page, lru)->index;
+ list_for_each_entry_reverse(page, page_list, lru) {
+ if (page->index == next_index) {
+ dout("readpages page %d %p\n", contig_pages, page);
+ pages[contig_pages] = page;
+ contig_pages++;
+ next_index++;
+ } else {
+ break;
+ }
+ }
+ *nr_pages = contig_pages;
+ return pages;
+}
+
+/*
+ * Read multiple pages. Leave pages we don't read + unlock in page_list;
+ * the caller (VM) cleans them up.
+ */
+static int ceph_readpages(struct file *file, struct address_space *mapping,
+ struct list_head *page_list, unsigned nr_pages)
+{
+ struct inode *inode = file->f_dentry->d_inode;
+ struct ceph_inode_info *ci = ceph_inode(inode);
+ struct ceph_osd_client *osdc = &ceph_inode_to_client(inode)->osdc;
+ int rc = 0;
+ struct page **pages;
+ struct pagevec pvec;
+ loff_t offset;
+ u64 len;
+
+ dout("readpages %p file %p nr_pages %d\n",
+ inode, file, nr_pages);
+
+ pages = page_vector_from_list(page_list, &nr_pages);
+ if (IS_ERR(pages))
+ return PTR_ERR(pages);
+
+ /* guess read extent */
+ offset = pages[0]->index << PAGE_CACHE_SHIFT;
+ len = nr_pages << PAGE_CACHE_SHIFT;
+ rc = ceph_osdc_readpages(osdc, ceph_vino(inode), &ci->i_layout,
+ offset, &len,
+ ci->i_truncate_seq, ci->i_truncate_size,
+ pages, nr_pages);
+ if (rc == -ENOENT)
+ rc = 0;
+ if (rc < 0)
+ goto out;
+
+ /* set uptodate and add to lru in pagevec-sized chunks */
+ pagevec_init(&pvec, 0);
+ for (; !list_empty(page_list) && len > 0;
+ rc -= PAGE_CACHE_SIZE, len -= PAGE_CACHE_SIZE) {
+ struct page *page =
+ list_entry(page_list->prev, struct page, lru);
+
+ list_del(&page->lru);
+
+ if (rc < (int)PAGE_CACHE_SIZE) {
+ /* zero (remainder of) page */
+ int s = rc < 0 ? 0 : rc;
+ zero_user_segment(page, s, PAGE_CACHE_SIZE);
+ }
+
+ if (add_to_page_cache(page, mapping, page->index, GFP_NOFS)) {
+ page_cache_release(page);
+ dout("readpages %p add_to_page_cache failed %p\n",
+ inode, page);
+ continue;
+ }
+ dout("readpages %p adding %p idx %lu\n", inode, page,
+ page->index);
+ flush_dcache_page(page);
+ SetPageUptodate(page);
+ unlock_page(page);
+ if (pagevec_add(&pvec, page) == 0)
+ pagevec_lru_add_file(&pvec); /* add to lru */
+ }
+ pagevec_lru_add_file(&pvec);
+ rc = 0;
+
+out:
+ kfree(pages);
+ return rc;
+}
+
+/*
+ * Get ref for the oldest snapc for an inode with dirty data... that is, the
+ * only snap context we are allowed to write back.
+ *
+ * Caller holds i_lock.
+ */
+static struct ceph_snap_context *__get_oldest_context(struct inode *inode,
+ u64 *snap_size)
+{
+ struct ceph_inode_info *ci = ceph_inode(inode);
+ struct ceph_snap_context *snapc = NULL;
+ struct ceph_cap_snap *capsnap = NULL;
+
+ list_for_each_entry(capsnap, &ci->i_cap_snaps, ci_item) {
+ dout(" cap_snap %p snapc %p has %d dirty pages\n", capsnap,
+ capsnap->context, capsnap->dirty_pages);
+ if (capsnap->dirty_pages) {
+ snapc = ceph_get_snap_context(capsnap->context);
+ if (snap_size)
+ *snap_size = capsnap->size;
+ break;
+ }
+ }
+ if (!snapc && ci->i_snap_realm) {
+ snapc = ceph_get_snap_context(ci->i_snap_realm->cached_context);
+ dout(" head snapc %p has %d dirty pages\n",
+ snapc, ci->i_wrbuffer_ref_head);
+ }
+ return snapc;
+}
+
+static struct ceph_snap_context *get_oldest_context(struct inode *inode,
+ u64 *snap_size)
+{
+ struct ceph_snap_context *snapc = NULL;
+
+ spin_lock(&inode->i_lock);
+ snapc = __get_oldest_context(inode, snap_size);
+ spin_unlock(&inode->i_lock);
+ return snapc;
+}
+
+/*
+ * Write a single page, but leave the page locked.
+ *
+ * If we get a write error, set the page error bit, but still adjust the
+ * dirty page accounting (i.e., page is no longer dirty).
+ */
+static int writepage_nounlock(struct page *page, struct writeback_control *wbc)
+{
+ struct inode *inode;
+ struct ceph_inode_info *ci;
+ struct ceph_osd_client *osdc;
+ loff_t page_off = page->index << PAGE_CACHE_SHIFT;
+ int len = PAGE_CACHE_SIZE;
+ loff_t i_size;
+ int err = 0;
+ struct ceph_snap_context *snapc;
+ u64 snap_size = 0;
+
+ 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);
+ osdc = &ceph_inode_to_client(inode)->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;
+ }
+ if (snapc != get_oldest_context(inode, &snap_size)) {
+ dout("writepage %p page %p snapc %p not writeable - noop\n",
+ inode, page, (void *)page->private);
+ /* we should only noop if called by kswapd */
+ WARN_ON((current->flags & PF_MEMALLOC) == 0);
+ goto out;
+ }
+
+ /* is this a partial page at end of file? */
+ if (snap_size)
+ i_size = snap_size;
+ else
+ i_size = i_size_read(inode);
+ if (i_size < page_off + len)
+ len = i_size - page_off;
+
+ dout("writepage %p page %p index %lu on %llu~%u\n",
+ inode, page, page->index, page_off, len);
+
+ set_page_writeback(page);
+ err = ceph_osdc_writepages(osdc, ceph_vino(inode),
+ &ci->i_layout, snapc,
+ page_off, len,
+ ci->i_truncate_seq, ci->i_truncate_size,
+ &inode->i_mtime,
+ &page, 1, 0, 0, true);
+ if (err < 0) {
+ dout("writepage setting page/mapping error %d %p\n", err, page);
+ SetPageError(page);
+ mapping_set_error(&inode->i_data, err);
+ if (wbc)
+ wbc->pages_skipped++;
+ } else {
+ dout("writepage cleaned page %p\n", page);
+ err = 0; /* vfs expects us to return 0 */
+ }
+ page->private = 0;
+ ClearPagePrivate(page);
+ end_page_writeback(page);
+ ceph_put_wrbuffer_cap_refs(ci, 1, snapc);
+ ceph_put_snap_context(snapc);
+out:
+ return err;
+}
+
+static int ceph_writepage(struct page *page, struct writeback_control *wbc)
+{
+ int err = writepage_nounlock(page, wbc);
+ unlock_page(page);
+ 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;
+ loff_t offset = req->r_pages[0]->index << PAGE_CACHE_SHIFT;
+ 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;
+
+ /* 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) {
+ wrote = (bytes + (offset & ~PAGE_CACHE_MASK) + ~PAGE_CACHE_MASK)
+ >> PAGE_CACHE_SHIFT;
+ WARN_ON(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));
+
+ if (i >= wrote) {
+ dout("inode %p skipping page %p\n", inode, page);
+ wbc->pages_skipped++;
+ }
+ page->private = 0;
+ ClearPagePrivate(page);
+ ceph_put_snap_context(snapc);
+ dout("unlocking %d %p\n", i, page);
+ end_page_writeback(page);
+ 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 = ceph_inode_to_client(inode);
+ pgoff_t index, start, end;
+ int range_whole = 0;
+ int should_loop = 1;
+ pgoff_t max_pages = 0, max_pages_ever = 0;
+ struct ceph_snap_context *snapc = NULL, *last_snapc = NULL;
+ struct pagevec pvec;
+ int done = 0;
+ int rc = 0;
+ unsigned wsize = 1 << inode->i_blkbits;
+ struct ceph_osd_request *req = NULL;
+ int do_sync;
+ u64 snap_size = 0;
+
+ /*
+ * Include a 'sync' in the OSD request if this is a data
+ * integrity write (e.g., O_SYNC write or fsync()), or if our
+ * cap is being revoked.
+ */
+ do_sync = wbc->sync_mode == WB_SYNC_ALL;
+ if (ceph_caps_revoking(ci, CEPH_CAP_FILE_BUFFER))
+ do_sync = 1;
+ dout("writepages_start %p dosync=%d (mode=%s)\n",
+ inode, do_sync,
+ wbc->sync_mode == WB_SYNC_NONE ? "NONE" :
+ (wbc->sync_mode == WB_SYNC_ALL ? "ALL" : "HOLD"));
+
+ client = ceph_inode_to_client(inode);
+ if (client->mount_state == CEPH_MOUNT_SHUTDOWN) {
+ pr_warning("writepage_start %p on forced umount\n", inode);
+ return -EIO; /* we're in a forced umount, don't write! */
+ }
+ 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;
+
+ next = 0;
+ locked_pages = 0;
+ max_pages = max_pages_ever;
+
+get_more_pages:
+ first = -1;
+ want = min(end - index,
+ min((pgoff_t)PAGEVEC_SIZE,
+ max_pages - (pgoff_t)locked_pages) - 1)
+ + 1;
+ pvec_pages = pagevec_lookup_tag(&pvec, mapping, &index,
+ PAGECACHE_TAG_DIRTY,
+ want);
+ dout("pagevec_lookup_tag got %d\n", pvec_pages);
+ if (!pvec_pages && !locked_pages)
+ break;
+ for (i = 0; i < pvec_pages && locked_pages < max_pages; i++) {
+ page = pvec.pages[i];
+ dout("? %p idx %lu\n", page, page->index);
+ if (locked_pages == 0)
+ lock_page(page); /* first page */
+ else if (!trylock_page(page))
+ break;
+
+ /* only dirty pages, or our accounting breaks */
+ if (unlikely(!PageDirty(page)) ||
+ unlikely(page->mapping != mapping)) {
+ dout("!dirty or !mapping %p\n", page);
+ unlock_page(page);
+ break;
+ }
+ if (!wbc->range_cyclic && page->index > end) {
+ dout("end of range %p\n", page);
+ done = 1;
+ unlock_page(page);
+ break;
+ }
+ if (next && (page->index != next)) {
+ dout("not consecutive %p\n", page);
+ unlock_page(page);
+ break;
+ }
+ if (wbc->sync_mode != WB_SYNC_NONE) {
+ dout("waiting on writeback %p\n", page);
+ wait_on_page_writeback(page);
+ }
+ if ((snap_size && page_offset(page) > snap_size) ||
+ (!snap_size &&
+ page_offset(page) > i_size_read(inode))) {
+ dout("%p page eof %llu\n", page, snap_size ?
+ snap_size : i_size_read(inode));
+ done = 1;
+ unlock_page(page);
+ break;
+ }
+ if (PageWriteback(page)) {
+ dout("%p under writeback\n", page);
+ unlock_page(page);
+ break;
+ }
+
+ /* only if matching snap context */
+ if (snapc != (void *)page->private) {
+ dout("page snapc %p != oldest %p\n",
+ (void *)page->private, snapc);
+ unlock_page(page);
+ if (!locked_pages)
+ continue; /* keep looking for snap */
+ break;
+ }
+
+ if (!clear_page_dirty_for_io(page)) {
+ dout("%p !clear_page_dirty_for_io\n", page);
+ unlock_page(page);
+ break;
+ }
+
+ /* ok */
+ if (locked_pages == 0) {
+ /* prepare async write request */
+ offset = page->index << PAGE_CACHE_SHIFT;
+ len = wsize;
+ req = ceph_osdc_new_request(&client->osdc,
+ &ci->i_layout,
+ ceph_vino(inode),
+ offset, &len,
+ CEPH_OSD_OP_WRITE,
+ CEPH_OSD_FLAG_WRITE |
+ CEPH_OSD_FLAG_ONDISK,
+ snapc, do_sync,
+ ci->i_truncate_seq,
+ ci->i_truncate_size,
+ &inode->i_mtime, true, 1);
+ max_pages = req->r_num_pages;
+
+ alloc_page_vec(client, req);
+ req->r_callback = writepages_finish;
+ req->r_inode = inode;
+ req->r_wbc = wbc;
+ }
+
+ /* note position of first page in pvec */
+ if (first < 0)
+ first = i;
+ dout("%p will write page %p idx %lu\n",
+ inode, page, page->index);
+ set_page_writeback(page);
+ req->r_pages[locked_pages] = page;
+ locked_pages++;
+ next = page->index + 1;
+ }
+
+ /* did we get anything? */
+ if (!locked_pages)
+ goto release_pvec_pages;
+ if (i) {
+ int j;
+ BUG_ON(!locked_pages || first < 0);
+
+ if (pvec_pages && i == pvec_pages &&
+ locked_pages < max_pages) {
+ dout("reached end pvec, trying for more\n");
+ pagevec_reinit(&pvec);
+ goto get_more_pages;
+ }
+
+ /* shift unused pages over in the pvec... we
+ * will need to release them below. */
+ for (j = i; j < pvec_pages; j++) {
+ dout(" pvec leftover page %p\n",
+ pvec.pages[j]);
+ pvec.pages[j-i+first] = pvec.pages[j];
+ }
+ pvec.nr -= i-first;
+ }
+
+ /* submit the write */
+ offset = req->r_pages[0]->index << PAGE_CACHE_SHIFT;
+ len = min((snap_size ? snap_size : i_size_read(inode)) - offset,
+ (u64)locked_pages << PAGE_CACHE_SHIFT);
+ dout("writepages got %d pages at %llu~%llu\n",
+ locked_pages, offset, len);
+
+ /* revise final length, page count */
+ req->r_num_pages = locked_pages;
+ reqhead = req->r_request->front.iov_base;
+ op = (void *)(reqhead + 1);
+ op->extent.length = cpu_to_le64(len);
+ op->payload_len = cpu_to_le32(len);
+ req->r_request->hdr.data_len = cpu_to_le32(len);
+
+ ceph_osdc_start_request(&client->osdc, req, true);
+ req = NULL;
+
+ /* continue? */
+ index = next;
+ wbc->nr_to_write -= locked_pages;
+ if (wbc->nr_to_write <= 0)
+ done = 1;
+
+release_pvec_pages:
+ dout("pagevec_release on %d pages (%p)\n", (int)pvec.nr,
+ pvec.nr ? pvec.pages[0] : NULL);
+ pagevec_release(&pvec);
+
+ if (locked_pages && !done)
+ goto retry;
+ }
+
+ if (should_loop && !done) {
+ /* more to do; loop back to beginning of file */
+ dout("writepages looping back to beginning of file\n");
+ should_loop = 0;
+ index = 0;
+ goto retry;
+ }
+
+ if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0))
+ mapping->writeback_index = index;
+
+out:
+ if (req)
+ ceph_osdc_put_request(req);
+ if (rc > 0)
+ rc = 0; /* vfs expects us to return 0 */
+ ceph_put_snap_context(snapc);
+ dout("writepages done, rc = %d\n", rc);
+out_final:
+ return rc;
+}
+
+
+
+/*
+ * See if a given @snapc is either writeable, or already written.
+ */
+static int context_is_writeable_or_written(struct inode *inode,
+ struct ceph_snap_context *snapc)
+{
+ struct ceph_snap_context *oldest = get_oldest_context(inode, NULL);
+ return !oldest || snapc->seq <= oldest->seq;
+}
+
+/*
+ * We are only allowed to write into/dirty the page if the page is
+ * clean, or already dirty within the same snap context.
+ */
+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 ceph_inode_info *ci = ceph_inode(inode);
+ struct ceph_mds_client *mdsc = &ceph_inode_to_client(inode)->mdsc;
+ struct page *page;
+ pgoff_t index = pos >> PAGE_CACHE_SHIFT;
+ loff_t page_off = pos & PAGE_CACHE_MASK;
+ int pos_in_page = pos & ~PAGE_CACHE_MASK;
+ int end_in_page = pos_in_page + len;
+ loff_t i_size;
+ struct ceph_snap_context *snapc;
+ int r;
+
+ /* get a page*/
+retry:
+ 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);
+
+retry_locked:
+ /* writepages currently holds page lock, but if we change that later, */
+ wait_on_page_writeback(page);
+
+ /* check snap context */
+ BUG_ON(!ci->i_snap_realm);
+ down_read(&mdsc->snap_rwsem);
+ BUG_ON(!ci->i_snap_realm->cached_context);
+ if (page->private &&
+ (void *)page->private != ci->i_snap_realm->cached_context) {
+ /*
+ * this page is already dirty in another (older) snap
+ * context! is it writeable now?
+ */
+ snapc = get_oldest_context(inode, NULL);
+ up_read(&mdsc->snap_rwsem);
+
+ if (snapc != (void *)page->private) {
+ dout(" page %p snapc %p not current or oldest\n",
+ page, (void *)page->private);
+ /*
+ * queue for writeback, and wait for snapc to
+ * be writeable or written
+ */
+ snapc = ceph_get_snap_context((void *)page->private);
+ unlock_page(page);
+ if (ceph_queue_writeback(inode))
+ igrab(inode);
+ wait_event_interruptible(ci->i_cap_wq,
+ context_is_writeable_or_written(inode, snapc));
+ ceph_put_snap_context(snapc);
+ goto retry;
+ }
+
+ /* 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 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_mds_client *mdsc = &ceph_inode_to_client(inode)->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;
+ struct page *locked_page = NULL;
+ void *fsdata = NULL;
+ 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);
+ ret = ceph_write_begin(vma->vm_file, inode->i_mapping, off, len, 0,
+ &locked_page, &fsdata);
+ WARN_ON(page != locked_page);
+ if (!ret) {
+ /*
+ * doing the following, instead of calling
+ * ceph_write_end. Note that we keep the
+ * page locked
+ */
+ set_page_dirty(page);
+ up_read(&mdsc->snap_rwsem);
+ page_cache_release(page);
+ ret = VM_FAULT_LOCKED;
+ } else {
+ ret = VM_FAULT_SIGBUS;
+ }
+ dout("page_mkwrite %p %llu~%llu = %d\n", inode, off, len, ret);
+ 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;
+}
projects / GitHub / moto-9609 / android_kernel_motorola_exynos9610.git / commitdiff