return copied;
}
+/**
+ * populate_page - copy data nodes into a page for bulk-read.
+ * @c: UBIFS file-system description object
+ * @page: page
+ * @bu: bulk-read information
+ * @n: next zbranch slot
+ *
+ * This function returns %0 on success and a negative error code on failure.
+ */
+static int populate_page(struct ubifs_info *c, struct page *page,
+ struct bu_info *bu, int *n)
+{
+ int i = 0, nn = *n, offs = bu->zbranch[0].offs, hole = 1, read = 0;
+ struct inode *inode = page->mapping->host;
+ loff_t i_size = i_size_read(inode);
+ unsigned int page_block;
+ void *addr, *zaddr;
+ pgoff_t end_index;
+
+ dbg_gen("ino %lu, pg %lu, i_size %lld, flags %#lx",
+ inode->i_ino, page->index, i_size, page->flags);
+
+ addr = zaddr = kmap(page);
+
+ end_index = (i_size + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT;
+ if (!i_size || page->index > end_index) {
+ memset(addr, 0, PAGE_CACHE_SIZE);
+ goto out_hole;
+ }
+
+ page_block = page->index << UBIFS_BLOCKS_PER_PAGE_SHIFT;
+ while (1) {
+ int err, len, out_len, dlen;
+
+ if (nn >= bu->cnt ||
+ key_block(c, &bu->zbranch[nn].key) != page_block)
+ memset(addr, 0, UBIFS_BLOCK_SIZE);
+ else {
+ struct ubifs_data_node *dn;
+
+ dn = bu->buf + (bu->zbranch[nn].offs - offs);
+
+ ubifs_assert(dn->ch.sqnum >
+ ubifs_inode(inode)->creat_sqnum);
+
+ len = le32_to_cpu(dn->size);
+ if (len <= 0 || len > UBIFS_BLOCK_SIZE)
+ goto out_err;
+
+ dlen = le32_to_cpu(dn->ch.len) - UBIFS_DATA_NODE_SZ;
+ out_len = UBIFS_BLOCK_SIZE;
+ err = ubifs_decompress(&dn->data, dlen, addr, &out_len,
+ le16_to_cpu(dn->compr_type));
+ if (err || len != out_len)
+ goto out_err;
+
+ if (len < UBIFS_BLOCK_SIZE)
+ memset(addr + len, 0, UBIFS_BLOCK_SIZE - len);
+
+ nn += 1;
+ hole = 0;
+ read = (i << UBIFS_BLOCK_SHIFT) + len;
+ }
+ if (++i >= UBIFS_BLOCKS_PER_PAGE)
+ break;
+ addr += UBIFS_BLOCK_SIZE;
+ page_block += 1;
+ }
+
+ if (end_index == page->index) {
+ int len = i_size & (PAGE_CACHE_SIZE - 1);
+
+ if (len < read)
+ memset(zaddr + len, 0, read - len);
+ }
+
+out_hole:
+ if (hole) {
+ SetPageChecked(page);
+ dbg_gen("hole");
+ }
+
+ SetPageUptodate(page);
+ ClearPageError(page);
+ flush_dcache_page(page);
+ kunmap(page);
+ *n = nn;
+ return 0;
+
+out_err:
+ ClearPageUptodate(page);
+ SetPageError(page);
+ flush_dcache_page(page);
+ kunmap(page);
+ ubifs_err("bad data node (block %u, inode %lu)",
+ page_block, inode->i_ino);
+ return -EINVAL;
+}
+
+/**
+ * ubifs_do_bulk_read - do bulk-read.
+ * @c: UBIFS file-system description object
+ * @page1: first page
+ *
+ * This function returns %1 if the bulk-read is done, otherwise %0 is returned.
+ */
+static int ubifs_do_bulk_read(struct ubifs_info *c, struct page *page1)
+{
+ pgoff_t offset = page1->index, end_index;
+ struct address_space *mapping = page1->mapping;
+ struct inode *inode = mapping->host;
+ struct ubifs_inode *ui = ubifs_inode(inode);
+ struct bu_info *bu;
+ int err, page_idx, page_cnt, ret = 0, n = 0;
+ loff_t isize;
+
+ bu = kmalloc(sizeof(struct bu_info), GFP_NOFS);
+ if (!bu)
+ return 0;
+
+ bu->buf_len = c->bulk_read_buf_size;
+ bu->buf = kmalloc(bu->buf_len, GFP_NOFS);
+ if (!bu->buf)
+ goto out_free;
+
+ data_key_init(c, &bu->key, inode->i_ino,
+ offset << UBIFS_BLOCKS_PER_PAGE_SHIFT);
+
+ err = ubifs_tnc_get_bu_keys(c, bu);
+ if (err)
+ goto out_warn;
+
+ if (bu->eof) {
+ /* Turn off bulk-read at the end of the file */
+ ui->read_in_a_row = 1;
+ ui->bulk_read = 0;
+ }
+
+ page_cnt = bu->blk_cnt >> UBIFS_BLOCKS_PER_PAGE_SHIFT;
+ if (!page_cnt) {
+ /*
+ * This happens when there are multiple blocks per page and the
+ * blocks for the first page we are looking for, are not
+ * together. If all the pages were like this, bulk-read would
+ * reduce performance, so we turn it off for a while.
+ */
+ ui->read_in_a_row = 0;
+ ui->bulk_read = 0;
+ goto out_free;
+ }
+
+ if (bu->cnt) {
+ err = ubifs_tnc_bulk_read(c, bu);
+ if (err)
+ goto out_warn;
+ }
+
+ err = populate_page(c, page1, bu, &n);
+ if (err)
+ goto out_warn;
+
+ unlock_page(page1);
+ ret = 1;
+
+ isize = i_size_read(inode);
+ if (isize == 0)
+ goto out_free;
+ end_index = ((isize - 1) >> PAGE_CACHE_SHIFT);
+
+ for (page_idx = 1; page_idx < page_cnt; page_idx++) {
+ pgoff_t page_offset = offset + page_idx;
+ struct page *page;
+
+ if (page_offset > end_index)
+ break;
+ page = find_or_create_page(mapping, page_offset,
+ GFP_NOFS | __GFP_COLD);
+ if (!page)
+ break;
+ if (!PageUptodate(page))
+ err = populate_page(c, page, bu, &n);
+ unlock_page(page);
+ page_cache_release(page);
+ if (err)
+ break;
+ }
+
+ ui->last_page_read = offset + page_idx - 1;
+
+out_free:
+ kfree(bu->buf);
+ kfree(bu);
+ return ret;
+
+out_warn:
+ ubifs_warn("ignoring error %d and skipping bulk-read", err);
+ goto out_free;
+}
+
+/**
+ * ubifs_bulk_read - determine whether to bulk-read and, if so, do it.
+ * @page: page from which to start bulk-read.
+ *
+ * Some flash media are capable of reading sequentially at faster rates. UBIFS
+ * bulk-read facility is designed to take advantage of that, by reading in one
+ * go consecutive data nodes that are also located consecutively in the same
+ * LEB. This function returns %1 if a bulk-read is done and %0 otherwise.
+ */
+static int ubifs_bulk_read(struct page *page)
+{
+ struct inode *inode = page->mapping->host;
+ struct ubifs_info *c = inode->i_sb->s_fs_info;
+ struct ubifs_inode *ui = ubifs_inode(inode);
+ pgoff_t index = page->index, last_page_read = ui->last_page_read;
+ int ret = 0;
+
+ ui->last_page_read = index;
+
+ if (!c->bulk_read)
+ return 0;
+ /*
+ * Bulk-read is protected by ui_mutex, but it is an optimization, so
+ * don't bother if we cannot lock the mutex.
+ */
+ if (!mutex_trylock(&ui->ui_mutex))
+ return 0;
+ if (index != last_page_read + 1) {
+ /* Turn off bulk-read if we stop reading sequentially */
+ ui->read_in_a_row = 1;
+ if (ui->bulk_read)
+ ui->bulk_read = 0;
+ goto out_unlock;
+ }
+ if (!ui->bulk_read) {
+ ui->read_in_a_row += 1;
+ if (ui->read_in_a_row < 3)
+ goto out_unlock;
+ /* Three reads in a row, so switch on bulk-read */
+ ui->bulk_read = 1;
+ }
+ ret = ubifs_do_bulk_read(c, page);
+out_unlock:
+ mutex_unlock(&ui->ui_mutex);
+ return ret;
+}
+
static int ubifs_readpage(struct file *file, struct page *page)
{
+ if (ubifs_bulk_read(page))
+ return 0;
do_readpage(page);
unlock_page(page);
return 0;
projects / linux-2.6-omap-h63xx.git / blobdiff