gfs2_log_bmap(sdp));
}
- int i;
+ /**
+ * gfs2_end_log_read - end I/O callback for reads from the log
+ * @bio: The bio
+ *
+ * Simply unlock the pages in the bio. The main thread will wait on them and
+ * process them in order as necessary.
+ */
+
+ static void gfs2_end_log_read(struct bio *bio)
+ {
+ struct page *page;
+ struct bio_vec *bvec;
- bio_for_each_segment_all(bvec, bio, i, iter_all) {
+ struct bvec_iter_all iter_all;
+
++ bio_for_each_segment_all(bvec, bio, iter_all) {
+ page = bvec->bv_page;
+ if (bio->bi_status) {
+ int err = blk_status_to_errno(bio->bi_status);
+
+ SetPageError(page);
+ mapping_set_error(page->mapping, err);
+ }
+ unlock_page(page);
+ }
+
+ bio_put(bio);
+ }
+
+ /**
+ * gfs2_jhead_pg_srch - Look for the journal head in a given page.
+ * @jd: The journal descriptor
+ * @page: The page to look in
+ *
+ * Returns: 1 if found, 0 otherwise.
+ */
+
+ static bool gfs2_jhead_pg_srch(struct gfs2_jdesc *jd,
+ struct gfs2_log_header_host *head,
+ struct page *page)
+ {
+ struct gfs2_sbd *sdp = GFS2_SB(jd->jd_inode);
+ struct gfs2_log_header_host uninitialized_var(lh);
+ void *kaddr = kmap_atomic(page);
+ unsigned int offset;
+ bool ret = false;
+
+ for (offset = 0; offset < PAGE_SIZE; offset += sdp->sd_sb.sb_bsize) {
+ if (!__get_log_header(sdp, kaddr + offset, 0, &lh)) {
+ if (lh.lh_sequence > head->lh_sequence)
+ *head = lh;
+ else {
+ ret = true;
+ break;
+ }
+ }
+ }
+ kunmap_atomic(kaddr);
+ return ret;
+ }
+
+ /**
+ * gfs2_jhead_process_page - Search/cleanup a page
+ * @jd: The journal descriptor
+ * @index: Index of the page to look into
+ * @done: If set, perform only cleanup, else search and set if found.
+ *
+ * Find the page with 'index' in the journal's mapping. Search the page for
+ * the journal head if requested (cleanup == false). Release refs on the
+ * page so the page cache can reclaim it (put_page() twice). We grabbed a
+ * reference on this page two times, first when we did a find_or_create_page()
+ * to obtain the page to add it to the bio and second when we do a
+ * find_get_page() here to get the page to wait on while I/O on it is being
+ * completed.
+ * This function is also used to free up a page we might've grabbed but not
+ * used. Maybe we added it to a bio, but not submitted it for I/O. Or we
+ * submitted the I/O, but we already found the jhead so we only need to drop
+ * our references to the page.
+ */
+
+ static void gfs2_jhead_process_page(struct gfs2_jdesc *jd, unsigned long index,
+ struct gfs2_log_header_host *head,
+ bool *done)
+ {
+ struct page *page;
+
+ page = find_get_page(jd->jd_inode->i_mapping, index);
+ wait_on_page_locked(page);
+
+ if (PageError(page))
+ *done = true;
+
+ if (!*done)
+ *done = gfs2_jhead_pg_srch(jd, head, page);
+
+ put_page(page); /* Once for find_get_page */
+ put_page(page); /* Once more for find_or_create_page */
+ }
+
+ /**
+ * gfs2_find_jhead - find the head of a log
+ * @jd: The journal descriptor
+ * @head: The log descriptor for the head of the log is returned here
+ *
+ * Do a search of a journal by reading it in large chunks using bios and find
+ * the valid log entry with the highest sequence number. (i.e. the log head)
+ *
+ * Returns: 0 on success, errno otherwise
+ */
+ int gfs2_find_jhead(struct gfs2_jdesc *jd, struct gfs2_log_header_host *head,
+ bool keep_cache)
+ {
+ struct gfs2_sbd *sdp = GFS2_SB(jd->jd_inode);
+ struct address_space *mapping = jd->jd_inode->i_mapping;
+ unsigned int block = 0, blocks_submitted = 0, blocks_read = 0;
+ unsigned int bsize = sdp->sd_sb.sb_bsize;
+ unsigned int bsize_shift = sdp->sd_sb.sb_bsize_shift;
+ unsigned int shift = PAGE_SHIFT - bsize_shift;
+ unsigned int readhead_blocks = BIO_MAX_PAGES << shift;
+ struct gfs2_journal_extent *je;
+ int sz, ret = 0;
+ struct bio *bio = NULL;
+ struct page *page = NULL;
+ bool done = false;
+ errseq_t since;
+
+ memset(head, 0, sizeof(*head));
+ if (list_empty(&jd->extent_list))
+ gfs2_map_journal_extents(sdp, jd);
+
+ since = filemap_sample_wb_err(mapping);
+ list_for_each_entry(je, &jd->extent_list, list) {
+ for (; block < je->lblock + je->blocks; block++) {
+ u64 dblock;
+
+ if (!page) {
+ page = find_or_create_page(mapping,
+ block >> shift, GFP_NOFS);
+ if (!page) {
+ ret = -ENOMEM;
+ done = true;
+ goto out;
+ }
+ }
+
+ if (bio) {
+ unsigned int off;
+
+ off = (block << bsize_shift) & ~PAGE_MASK;
+ sz = bio_add_page(bio, page, bsize, off);
+ if (sz == bsize) { /* block added */
+ if (off + bsize == PAGE_SIZE) {
+ page = NULL;
+ goto page_added;
+ }
+ continue;
+ }
+ blocks_submitted = block + 1;
+ submit_bio(bio);
+ bio = NULL;
+ }
+
+ dblock = je->dblock + (block - je->lblock);
+ bio = gfs2_log_alloc_bio(sdp, dblock, gfs2_end_log_read);
+ bio->bi_opf = REQ_OP_READ;
+ sz = bio_add_page(bio, page, bsize, 0);
+ gfs2_assert_warn(sdp, sz == bsize);
+ if (bsize == PAGE_SIZE)
+ page = NULL;
+
+ page_added:
+ if (blocks_submitted < blocks_read + readhead_blocks) {
+ /* Keep at least one bio in flight */
+ continue;
+ }
+
+ gfs2_jhead_process_page(jd, blocks_read >> shift, head, &done);
+ blocks_read += PAGE_SIZE >> bsize_shift;
+ if (done)
+ goto out; /* found */
+ }
+ }
+
+ out:
+ if (bio)
+ submit_bio(bio);
+ while (blocks_read < block) {
+ gfs2_jhead_process_page(jd, blocks_read >> shift, head, &done);
+ blocks_read += PAGE_SIZE >> bsize_shift;
+ }
+
+ if (!ret)
+ ret = filemap_check_wb_err(mapping, since);
+
+ if (!keep_cache)
+ truncate_inode_pages(mapping, 0);
+
+ return ret;
+ }
+
static struct page *gfs2_get_log_desc(struct gfs2_sbd *sdp, u32 ld_type,
u32 ld_length, u32 ld_data1)
{
projects / linux-2.6-block.git / commitdiff