--- /dev/null
+/*
+ * GPL HEADER START
+ *
+ * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 only,
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License version 2 for more details (a copy is included
+ * in the LICENSE file that accompanied this code).
+ *
+ * You should have received a copy of the GNU General Public License
+ * version 2 along with this program; If not, see
+ * http://www.sun.com/software/products/lustre/docs/GPLv2.pdf
+ *
+ * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
+ * CA 95054 USA or visit www.sun.com if you need additional information or
+ * have any questions.
+ *
+ * GPL HEADER END
+ */
+/*
+ * Copyright (c) 2002, 2010, Oracle and/or its affiliates. All rights reserved.
+ * Use is subject to license terms.
+ *
+ * Copyright (c) 2011, 2012, Intel Corporation.
+ */
+/*
+ * This file is part of Lustre, http://www.lustre.org/
+ * Lustre is a trademark of Sun Microsystems, Inc.
+ *
+ * lustre/llite/rw.c
+ *
+ * Lustre Lite I/O page cache routines shared by different kernel revs
+ */
+
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/string.h>
+#include <linux/stat.h>
+#include <linux/errno.h>
+#include <linux/unistd.h>
+#include <linux/writeback.h>
+#include <linux/uaccess.h>
+
+#include <linux/fs.h>
+#include <linux/pagemap.h>
+/* current_is_kswapd() */
+#include <linux/swap.h>
+
+#define DEBUG_SUBSYSTEM S_LLITE
+
+#include "../include/lustre_lite.h"
+#include "../include/obd_cksum.h"
+#include "llite_internal.h"
+#include "../include/linux/lustre_compat25.h"
+
+/**
+ * Finalizes cl-data before exiting typical address_space operation. Dual to
+ * ll_cl_init().
+ */
+static void ll_cl_fini(struct ll_cl_context *lcc)
+{
+ struct lu_env *env = lcc->lcc_env;
+ struct cl_io *io = lcc->lcc_io;
+ struct cl_page *page = lcc->lcc_page;
+
+ LASSERT(lcc->lcc_cookie == current);
+ LASSERT(env != NULL);
+
+ if (page != NULL) {
+ lu_ref_del(&page->cp_reference, "cl_io", io);
+ cl_page_put(env, page);
+ }
+
+ cl_env_put(env, &lcc->lcc_refcheck);
+}
+
+/**
+ * Initializes common cl-data at the typical address_space operation entry
+ * point.
+ */
+static struct ll_cl_context *ll_cl_init(struct file *file,
+ struct page *vmpage, int create)
+{
+ struct ll_cl_context *lcc;
+ struct lu_env *env;
+ struct cl_io *io;
+ struct cl_object *clob;
+ struct ccc_io *cio;
+
+ int refcheck;
+ int result = 0;
+
+ clob = ll_i2info(vmpage->mapping->host)->lli_clob;
+ LASSERT(clob != NULL);
+
+ env = cl_env_get(&refcheck);
+ if (IS_ERR(env))
+ return ERR_CAST(env);
+
+ lcc = &vvp_env_info(env)->vti_io_ctx;
+ memset(lcc, 0, sizeof(*lcc));
+ lcc->lcc_env = env;
+ lcc->lcc_refcheck = refcheck;
+ lcc->lcc_cookie = current;
+
+ cio = ccc_env_io(env);
+ io = cio->cui_cl.cis_io;
+ if (io == NULL && create) {
+ struct inode *inode = vmpage->mapping->host;
+ loff_t pos;
+
+ if (mutex_trylock(&inode->i_mutex)) {
+ mutex_unlock(&(inode)->i_mutex);
+
+ /* this is too bad. Someone is trying to write the
+ * page w/o holding inode mutex. This means we can
+ * add dirty pages into cache during truncate */
+ CERROR("Proc %s is dirtying page w/o inode lock, this will break truncate\n",
+ current->comm);
+ dump_stack();
+ LBUG();
+ return ERR_PTR(-EIO);
+ }
+
+ /*
+ * Loop-back driver calls ->prepare_write().
+ * methods directly, bypassing file system ->write() operation,
+ * so cl_io has to be created here.
+ */
+ io = ccc_env_thread_io(env);
+ ll_io_init(io, file, 1);
+
+ /* No lock at all for this kind of IO - we can't do it because
+ * we have held page lock, it would cause deadlock.
+ * XXX: This causes poor performance to loop device - One page
+ * per RPC.
+ * In order to get better performance, users should use
+ * lloop driver instead.
+ */
+ io->ci_lockreq = CILR_NEVER;
+
+ pos = vmpage->index << PAGE_CACHE_SHIFT;
+
+ /* Create a temp IO to serve write. */
+ result = cl_io_rw_init(env, io, CIT_WRITE, pos, PAGE_CACHE_SIZE);
+ if (result == 0) {
+ cio->cui_fd = LUSTRE_FPRIVATE(file);
+ cio->cui_iter = NULL;
+ result = cl_io_iter_init(env, io);
+ if (result == 0) {
+ result = cl_io_lock(env, io);
+ if (result == 0)
+ result = cl_io_start(env, io);
+ }
+ } else
+ result = io->ci_result;
+ }
+
+ lcc->lcc_io = io;
+ if (io == NULL)
+ result = -EIO;
+ if (result == 0) {
+ struct cl_page *page;
+
+ LASSERT(io != NULL);
+ LASSERT(io->ci_state == CIS_IO_GOING);
+ LASSERT(cio->cui_fd == LUSTRE_FPRIVATE(file));
+ page = cl_page_find(env, clob, vmpage->index, vmpage,
+ CPT_CACHEABLE);
+ if (!IS_ERR(page)) {
+ lcc->lcc_page = page;
+ lu_ref_add(&page->cp_reference, "cl_io", io);
+ result = 0;
+ } else
+ result = PTR_ERR(page);
+ }
+ if (result) {
+ ll_cl_fini(lcc);
+ lcc = ERR_PTR(result);
+ }
+
+ CDEBUG(D_VFSTRACE, "%lu@"DFID" -> %d %p %p\n",
+ vmpage->index, PFID(lu_object_fid(&clob->co_lu)), result,
+ env, io);
+ return lcc;
+}
+
+static struct ll_cl_context *ll_cl_get(void)
+{
+ struct ll_cl_context *lcc;
+ struct lu_env *env;
+ int refcheck;
+
+ env = cl_env_get(&refcheck);
+ LASSERT(!IS_ERR(env));
+ lcc = &vvp_env_info(env)->vti_io_ctx;
+ LASSERT(env == lcc->lcc_env);
+ LASSERT(current == lcc->lcc_cookie);
+ cl_env_put(env, &refcheck);
+
+ /* env has got in ll_cl_init, so it is still usable. */
+ return lcc;
+}
+
+/**
+ * ->prepare_write() address space operation called by generic_file_write()
+ * for every page during write.
+ */
+int ll_prepare_write(struct file *file, struct page *vmpage, unsigned from,
+ unsigned to)
+{
+ struct ll_cl_context *lcc;
+ int result;
+
+ lcc = ll_cl_init(file, vmpage, 1);
+ if (!IS_ERR(lcc)) {
+ struct lu_env *env = lcc->lcc_env;
+ struct cl_io *io = lcc->lcc_io;
+ struct cl_page *page = lcc->lcc_page;
+
+ cl_page_assume(env, io, page);
+
+ result = cl_io_prepare_write(env, io, page, from, to);
+ if (result == 0) {
+ /*
+ * Add a reference, so that page is not evicted from
+ * the cache until ->commit_write() is called.
+ */
+ cl_page_get(page);
+ lu_ref_add(&page->cp_reference, "prepare_write",
+ current);
+ } else {
+ cl_page_unassume(env, io, page);
+ ll_cl_fini(lcc);
+ }
+ /* returning 0 in prepare assumes commit must be called
+ * afterwards */
+ } else {
+ result = PTR_ERR(lcc);
+ }
+ return result;
+}
+
+int ll_commit_write(struct file *file, struct page *vmpage, unsigned from,
+ unsigned to)
+{
+ struct ll_cl_context *lcc;
+ struct lu_env *env;
+ struct cl_io *io;
+ struct cl_page *page;
+ int result = 0;
+
+ lcc = ll_cl_get();
+ env = lcc->lcc_env;
+ page = lcc->lcc_page;
+ io = lcc->lcc_io;
+
+ LASSERT(cl_page_is_owned(page, io));
+ LASSERT(from <= to);
+ if (from != to) /* handle short write case. */
+ result = cl_io_commit_write(env, io, page, from, to);
+ if (cl_page_is_owned(page, io))
+ cl_page_unassume(env, io, page);
+
+ /*
+ * Release reference acquired by ll_prepare_write().
+ */
+ lu_ref_del(&page->cp_reference, "prepare_write", current);
+ cl_page_put(env, page);
+ ll_cl_fini(lcc);
+ return result;
+}
+
+struct obd_capa *cl_capa_lookup(struct inode *inode, enum cl_req_type crt)
+{
+ __u64 opc;
+
+ opc = crt == CRT_WRITE ? CAPA_OPC_OSS_WRITE : CAPA_OPC_OSS_RW;
+ return ll_osscapa_get(inode, opc);
+}
+
+static void ll_ra_stats_inc_sbi(struct ll_sb_info *sbi, enum ra_stat which);
+
+/**
+ * Get readahead pages from the filesystem readahead pool of the client for a
+ * thread.
+ *
+ * /param sbi superblock for filesystem readahead state ll_ra_info
+ * /param ria per-thread readahead state
+ * /param pages number of pages requested for readahead for the thread.
+ *
+ * WARNING: This algorithm is used to reduce contention on sbi->ll_lock.
+ * It should work well if the ra_max_pages is much greater than the single
+ * file's read-ahead window, and not too many threads contending for
+ * these readahead pages.
+ *
+ * TODO: There may be a 'global sync problem' if many threads are trying
+ * to get an ra budget that is larger than the remaining readahead pages
+ * and reach here at exactly the same time. They will compute /a ret to
+ * consume the remaining pages, but will fail at atomic_add_return() and
+ * get a zero ra window, although there is still ra space remaining. - Jay */
+
+static unsigned long ll_ra_count_get(struct ll_sb_info *sbi,
+ struct ra_io_arg *ria,
+ unsigned long pages)
+{
+ struct ll_ra_info *ra = &sbi->ll_ra_info;
+ long ret;
+
+ /* If read-ahead pages left are less than 1M, do not do read-ahead,
+ * otherwise it will form small read RPC(< 1M), which hurt server
+ * performance a lot. */
+ ret = min(ra->ra_max_pages - atomic_read(&ra->ra_cur_pages), pages);
+ if (ret < 0 || ret < min_t(long, PTLRPC_MAX_BRW_PAGES, pages)) {
+ ret = 0;
+ goto out;
+ }
+
+ /* If the non-strided (ria_pages == 0) readahead window
+ * (ria_start + ret) has grown across an RPC boundary, then trim
+ * readahead size by the amount beyond the RPC so it ends on an
+ * RPC boundary. If the readahead window is already ending on
+ * an RPC boundary (beyond_rpc == 0), or smaller than a full
+ * RPC (beyond_rpc < ret) the readahead size is unchanged.
+ * The (beyond_rpc != 0) check is skipped since the conditional
+ * branch is more expensive than subtracting zero from the result.
+ *
+ * Strided read is left unaligned to avoid small fragments beyond
+ * the RPC boundary from needing an extra read RPC. */
+ if (ria->ria_pages == 0) {
+ long beyond_rpc = (ria->ria_start + ret) % PTLRPC_MAX_BRW_PAGES;
+ if (/* beyond_rpc != 0 && */ beyond_rpc < ret)
+ ret -= beyond_rpc;
+ }
+
+ if (atomic_add_return(ret, &ra->ra_cur_pages) > ra->ra_max_pages) {
+ atomic_sub(ret, &ra->ra_cur_pages);
+ ret = 0;
+ }
+
+out:
+ return ret;
+}
+
+void ll_ra_count_put(struct ll_sb_info *sbi, unsigned long len)
+{
+ struct ll_ra_info *ra = &sbi->ll_ra_info;
+ atomic_sub(len, &ra->ra_cur_pages);
+}
+
+static void ll_ra_stats_inc_sbi(struct ll_sb_info *sbi, enum ra_stat which)
+{
+ LASSERTF(which >= 0 && which < _NR_RA_STAT, "which: %u\n", which);
+ lprocfs_counter_incr(sbi->ll_ra_stats, which);
+}
+
+void ll_ra_stats_inc(struct address_space *mapping, enum ra_stat which)
+{
+ struct ll_sb_info *sbi = ll_i2sbi(mapping->host);
+ ll_ra_stats_inc_sbi(sbi, which);
+}
+
+#define RAS_CDEBUG(ras) \
+ CDEBUG(D_READA, \
+ "lrp %lu cr %lu cp %lu ws %lu wl %lu nra %lu r %lu ri %lu" \
+ "csr %lu sf %lu sp %lu sl %lu \n", \
+ ras->ras_last_readpage, ras->ras_consecutive_requests, \
+ ras->ras_consecutive_pages, ras->ras_window_start, \
+ ras->ras_window_len, ras->ras_next_readahead, \
+ ras->ras_requests, ras->ras_request_index, \
+ ras->ras_consecutive_stride_requests, ras->ras_stride_offset, \
+ ras->ras_stride_pages, ras->ras_stride_length)
+
+static int index_in_window(unsigned long index, unsigned long point,
+ unsigned long before, unsigned long after)
+{
+ unsigned long start = point - before, end = point + after;
+
+ if (start > point)
+ start = 0;
+ if (end < point)
+ end = ~0;
+
+ return start <= index && index <= end;
+}
+
+static struct ll_readahead_state *ll_ras_get(struct file *f)
+{
+ struct ll_file_data *fd;
+
+ fd = LUSTRE_FPRIVATE(f);
+ return &fd->fd_ras;
+}
+
+void ll_ra_read_in(struct file *f, struct ll_ra_read *rar)
+{
+ struct ll_readahead_state *ras;
+
+ ras = ll_ras_get(f);
+
+ spin_lock(&ras->ras_lock);
+ ras->ras_requests++;
+ ras->ras_request_index = 0;
+ ras->ras_consecutive_requests++;
+ rar->lrr_reader = current;
+
+ list_add(&rar->lrr_linkage, &ras->ras_read_beads);
+ spin_unlock(&ras->ras_lock);
+}
+
+void ll_ra_read_ex(struct file *f, struct ll_ra_read *rar)
+{
+ struct ll_readahead_state *ras;
+
+ ras = ll_ras_get(f);
+
+ spin_lock(&ras->ras_lock);
+ list_del_init(&rar->lrr_linkage);
+ spin_unlock(&ras->ras_lock);
+}
+
+static struct ll_ra_read *ll_ra_read_get_locked(struct ll_readahead_state *ras)
+{
+ struct ll_ra_read *scan;
+
+ list_for_each_entry(scan, &ras->ras_read_beads, lrr_linkage) {
+ if (scan->lrr_reader == current)
+ return scan;
+ }
+ return NULL;
+}
+
+struct ll_ra_read *ll_ra_read_get(struct file *f)
+{
+ struct ll_readahead_state *ras;
+ struct ll_ra_read *bead;
+
+ ras = ll_ras_get(f);
+
+ spin_lock(&ras->ras_lock);
+ bead = ll_ra_read_get_locked(ras);
+ spin_unlock(&ras->ras_lock);
+ return bead;
+}
+
+static int cl_read_ahead_page(const struct lu_env *env, struct cl_io *io,
+ struct cl_page_list *queue, struct cl_page *page,
+ struct page *vmpage)
+{
+ struct ccc_page *cp;
+ int rc;
+
+ rc = 0;
+ cl_page_assume(env, io, page);
+ lu_ref_add(&page->cp_reference, "ra", current);
+ cp = cl2ccc_page(cl_page_at(page, &vvp_device_type));
+ if (!cp->cpg_defer_uptodate && !PageUptodate(vmpage)) {
+ rc = cl_page_is_under_lock(env, io, page);
+ if (rc == -EBUSY) {
+ cp->cpg_defer_uptodate = 1;
+ cp->cpg_ra_used = 0;
+ cl_page_list_add(queue, page);
+ rc = 1;
+ } else {
+ cl_page_delete(env, page);
+ rc = -ENOLCK;
+ }
+ } else {
+ /* skip completed pages */
+ cl_page_unassume(env, io, page);
+ }
+ lu_ref_del(&page->cp_reference, "ra", current);
+ cl_page_put(env, page);
+ return rc;
+}
+
+/**
+ * Initiates read-ahead of a page with given index.
+ *
+ * \retval +ve: page was added to \a queue.
+ *
+ * \retval -ENOLCK: there is no extent lock for this part of a file, stop
+ * read-ahead.
+ *
+ * \retval -ve, 0: page wasn't added to \a queue for other reason.
+ */
+static int ll_read_ahead_page(const struct lu_env *env, struct cl_io *io,
+ struct cl_page_list *queue,
+ pgoff_t index, struct address_space *mapping)
+{
+ struct page *vmpage;
+ struct cl_object *clob = ll_i2info(mapping->host)->lli_clob;
+ struct cl_page *page;
+ enum ra_stat which = _NR_RA_STAT; /* keep gcc happy */
+ int rc = 0;
+ const char *msg = NULL;
+
+ vmpage = grab_cache_page_nowait(mapping, index);
+ if (vmpage != NULL) {
+ /* Check if vmpage was truncated or reclaimed */
+ if (vmpage->mapping == mapping) {
+ page = cl_page_find(env, clob, vmpage->index,
+ vmpage, CPT_CACHEABLE);
+ if (!IS_ERR(page)) {
+ rc = cl_read_ahead_page(env, io, queue,
+ page, vmpage);
+ if (rc == -ENOLCK) {
+ which = RA_STAT_FAILED_MATCH;
+ msg = "lock match failed";
+ }
+ } else {
+ which = RA_STAT_FAILED_GRAB_PAGE;
+ msg = "cl_page_find failed";
+ }
+ } else {
+ which = RA_STAT_WRONG_GRAB_PAGE;
+ msg = "g_c_p_n returned invalid page";
+ }
+ if (rc != 1)
+ unlock_page(vmpage);
+ page_cache_release(vmpage);
+ } else {
+ which = RA_STAT_FAILED_GRAB_PAGE;
+ msg = "g_c_p_n failed";
+ }
+ if (msg != NULL) {
+ ll_ra_stats_inc(mapping, which);
+ CDEBUG(D_READA, "%s\n", msg);
+ }
+ return rc;
+}
+
+#define RIA_DEBUG(ria) \
+ CDEBUG(D_READA, "rs %lu re %lu ro %lu rl %lu rp %lu\n", \
+ ria->ria_start, ria->ria_end, ria->ria_stoff, ria->ria_length,\
+ ria->ria_pages)
+
+/* Limit this to the blocksize instead of PTLRPC_BRW_MAX_SIZE, since we don't
+ * know what the actual RPC size is. If this needs to change, it makes more
+ * sense to tune the i_blkbits value for the file based on the OSTs it is
+ * striped over, rather than having a constant value for all files here. */
+
+/* RAS_INCREASE_STEP should be (1UL << (inode->i_blkbits - PAGE_CACHE_SHIFT)).
+ * Temporarily set RAS_INCREASE_STEP to 1MB. After 4MB RPC is enabled
+ * by default, this should be adjusted corresponding with max_read_ahead_mb
+ * and max_read_ahead_per_file_mb otherwise the readahead budget can be used
+ * up quickly which will affect read performance significantly. See LU-2816 */
+#define RAS_INCREASE_STEP(inode) (ONE_MB_BRW_SIZE >> PAGE_CACHE_SHIFT)
+
+static inline int stride_io_mode(struct ll_readahead_state *ras)
+{
+ return ras->ras_consecutive_stride_requests > 1;
+}
+/* The function calculates how much pages will be read in
+ * [off, off + length], in such stride IO area,
+ * stride_offset = st_off, stride_length = st_len,
+ * stride_pages = st_pgs
+ *
+ * |------------------|*****|------------------|*****|------------|*****|....
+ * st_off
+ * |--- st_pgs ---|
+ * |----- st_len -----|
+ *
+ * How many pages it should read in such pattern
+ * |-------------------------------------------------------------|
+ * off
+ * |<------ length ------->|
+ *
+ * = |<----->| + |-------------------------------------| + |---|
+ * start_left st_pgs * i end_left
+ */
+static unsigned long
+stride_pg_count(pgoff_t st_off, unsigned long st_len, unsigned long st_pgs,
+ unsigned long off, unsigned long length)
+{
+ __u64 start = off > st_off ? off - st_off : 0;
+ __u64 end = off + length > st_off ? off + length - st_off : 0;
+ unsigned long start_left = 0;
+ unsigned long end_left = 0;
+ unsigned long pg_count;
+
+ if (st_len == 0 || length == 0 || end == 0)
+ return length;
+
+ start_left = do_div(start, st_len);
+ if (start_left < st_pgs)
+ start_left = st_pgs - start_left;
+ else
+ start_left = 0;
+
+ end_left = do_div(end, st_len);
+ if (end_left > st_pgs)
+ end_left = st_pgs;
+
+ CDEBUG(D_READA, "start %llu, end %llu start_left %lu end_left %lu \n",
+ start, end, start_left, end_left);
+
+ if (start == end)
+ pg_count = end_left - (st_pgs - start_left);
+ else
+ pg_count = start_left + st_pgs * (end - start - 1) + end_left;
+
+ CDEBUG(D_READA, "st_off %lu, st_len %lu st_pgs %lu off %lu length %lu pgcount %lu\n",
+ st_off, st_len, st_pgs, off, length, pg_count);
+
+ return pg_count;
+}
+
+static int ria_page_count(struct ra_io_arg *ria)
+{
+ __u64 length = ria->ria_end >= ria->ria_start ?
+ ria->ria_end - ria->ria_start + 1 : 0;
+
+ return stride_pg_count(ria->ria_stoff, ria->ria_length,
+ ria->ria_pages, ria->ria_start,
+ length);
+}
+
+/*Check whether the index is in the defined ra-window */
+static int ras_inside_ra_window(unsigned long idx, struct ra_io_arg *ria)
+{
+ /* If ria_length == ria_pages, it means non-stride I/O mode,
+ * idx should always inside read-ahead window in this case
+ * For stride I/O mode, just check whether the idx is inside
+ * the ria_pages. */
+ return ria->ria_length == 0 || ria->ria_length == ria->ria_pages ||
+ (idx >= ria->ria_stoff && (idx - ria->ria_stoff) %
+ ria->ria_length < ria->ria_pages);
+}
+
+static int ll_read_ahead_pages(const struct lu_env *env,
+ struct cl_io *io, struct cl_page_list *queue,
+ struct ra_io_arg *ria,
+ unsigned long *reserved_pages,
+ struct address_space *mapping,
+ unsigned long *ra_end)
+{
+ int rc, count = 0, stride_ria;
+ unsigned long page_idx;
+
+ LASSERT(ria != NULL);
+ RIA_DEBUG(ria);
+
+ stride_ria = ria->ria_length > ria->ria_pages && ria->ria_pages > 0;
+ for (page_idx = ria->ria_start; page_idx <= ria->ria_end &&
+ *reserved_pages > 0; page_idx++) {
+ if (ras_inside_ra_window(page_idx, ria)) {
+ /* If the page is inside the read-ahead window*/
+ rc = ll_read_ahead_page(env, io, queue,
+ page_idx, mapping);
+ if (rc == 1) {
+ (*reserved_pages)--;
+ count ++;
+ } else if (rc == -ENOLCK)
+ break;
+ } else if (stride_ria) {
+ /* If it is not in the read-ahead window, and it is
+ * read-ahead mode, then check whether it should skip
+ * the stride gap */
+ pgoff_t offset;
+ /* FIXME: This assertion only is valid when it is for
+ * forward read-ahead, it will be fixed when backward
+ * read-ahead is implemented */
+ LASSERTF(page_idx > ria->ria_stoff, "Invalid page_idx %lu rs %lu re %lu ro %lu rl %lu rp %lu\n",
+ page_idx,
+ ria->ria_start, ria->ria_end, ria->ria_stoff,
+ ria->ria_length, ria->ria_pages);
+ offset = page_idx - ria->ria_stoff;
+ offset = offset % (ria->ria_length);
+ if (offset > ria->ria_pages) {
+ page_idx += ria->ria_length - offset;
+ CDEBUG(D_READA, "i %lu skip %lu \n", page_idx,
+ ria->ria_length - offset);
+ continue;
+ }
+ }
+ }
+ *ra_end = page_idx;
+ return count;
+}
+
+int ll_readahead(const struct lu_env *env, struct cl_io *io,
+ struct ll_readahead_state *ras, struct address_space *mapping,
+ struct cl_page_list *queue, int flags)
+{
+ struct vvp_io *vio = vvp_env_io(env);
+ struct vvp_thread_info *vti = vvp_env_info(env);
+ struct cl_attr *attr = ccc_env_thread_attr(env);
+ unsigned long start = 0, end = 0, reserved;
+ unsigned long ra_end, len;
+ struct inode *inode;
+ struct ll_ra_read *bead;
+ struct ra_io_arg *ria = &vti->vti_ria;
+ struct ll_inode_info *lli;
+ struct cl_object *clob;
+ int ret = 0;
+ __u64 kms;
+
+ inode = mapping->host;
+ lli = ll_i2info(inode);
+ clob = lli->lli_clob;
+
+ memset(ria, 0, sizeof(*ria));
+
+ cl_object_attr_lock(clob);
+ ret = cl_object_attr_get(env, clob, attr);
+ cl_object_attr_unlock(clob);
+
+ if (ret != 0)
+ return ret;
+ kms = attr->cat_kms;
+ if (kms == 0) {
+ ll_ra_stats_inc(mapping, RA_STAT_ZERO_LEN);
+ return 0;
+ }
+
+ spin_lock(&ras->ras_lock);
+ if (vio->cui_ra_window_set)
+ bead = &vio->cui_bead;
+ else
+ bead = NULL;
+
+ /* Enlarge the RA window to encompass the full read */
+ if (bead != NULL && ras->ras_window_start + ras->ras_window_len <
+ bead->lrr_start + bead->lrr_count) {
+ ras->ras_window_len = bead->lrr_start + bead->lrr_count -
+ ras->ras_window_start;
+ }
+ /* Reserve a part of the read-ahead window that we'll be issuing */
+ if (ras->ras_window_len) {
+ start = ras->ras_next_readahead;
+ end = ras->ras_window_start + ras->ras_window_len - 1;
+ }
+ if (end != 0) {
+ unsigned long rpc_boundary;
+ /*
+ * Align RA window to an optimal boundary.
+ *
+ * XXX This would be better to align to cl_max_pages_per_rpc
+ * instead of PTLRPC_MAX_BRW_PAGES, because the RPC size may
+ * be aligned to the RAID stripe size in the future and that
+ * is more important than the RPC size.
+ */
+ /* Note: we only trim the RPC, instead of extending the RPC
+ * to the boundary, so to avoid reading too much pages during
+ * random reading. */
+ rpc_boundary = (end + 1) & (~(PTLRPC_MAX_BRW_PAGES - 1));
+ if (rpc_boundary > 0)
+ rpc_boundary--;
+
+ if (rpc_boundary > start)
+ end = rpc_boundary;
+
+ /* Truncate RA window to end of file */
+ end = min(end, (unsigned long)((kms - 1) >> PAGE_CACHE_SHIFT));
+
+ ras->ras_next_readahead = max(end, end + 1);
+ RAS_CDEBUG(ras);
+ }
+ ria->ria_start = start;
+ ria->ria_end = end;
+ /* If stride I/O mode is detected, get stride window*/
+ if (stride_io_mode(ras)) {
+ ria->ria_stoff = ras->ras_stride_offset;
+ ria->ria_length = ras->ras_stride_length;
+ ria->ria_pages = ras->ras_stride_pages;
+ }
+ spin_unlock(&ras->ras_lock);
+
+ if (end == 0) {
+ ll_ra_stats_inc(mapping, RA_STAT_ZERO_WINDOW);
+ return 0;
+ }
+ len = ria_page_count(ria);
+ if (len == 0)
+ return 0;
+
+ reserved = ll_ra_count_get(ll_i2sbi(inode), ria, len);
+ if (reserved < len)
+ ll_ra_stats_inc(mapping, RA_STAT_MAX_IN_FLIGHT);
+
+ CDEBUG(D_READA, "reserved page %lu ra_cur %d ra_max %lu\n", reserved,
+ atomic_read(&ll_i2sbi(inode)->ll_ra_info.ra_cur_pages),
+ ll_i2sbi(inode)->ll_ra_info.ra_max_pages);
+
+ ret = ll_read_ahead_pages(env, io, queue,
+ ria, &reserved, mapping, &ra_end);
+
+ LASSERTF(reserved >= 0, "reserved %lu\n", reserved);
+ if (reserved != 0)
+ ll_ra_count_put(ll_i2sbi(inode), reserved);
+
+ if (ra_end == end + 1 && ra_end == (kms >> PAGE_CACHE_SHIFT))
+ ll_ra_stats_inc(mapping, RA_STAT_EOF);
+
+ /* if we didn't get to the end of the region we reserved from
+ * the ras we need to go back and update the ras so that the
+ * next read-ahead tries from where we left off. we only do so
+ * if the region we failed to issue read-ahead on is still ahead
+ * of the app and behind the next index to start read-ahead from */
+ CDEBUG(D_READA, "ra_end %lu end %lu stride end %lu \n",
+ ra_end, end, ria->ria_end);
+
+ if (ra_end != end + 1) {
+ spin_lock(&ras->ras_lock);
+ if (ra_end < ras->ras_next_readahead &&
+ index_in_window(ra_end, ras->ras_window_start, 0,
+ ras->ras_window_len)) {
+ ras->ras_next_readahead = ra_end;
+ RAS_CDEBUG(ras);
+ }
+ spin_unlock(&ras->ras_lock);
+ }
+
+ return ret;
+}
+
+static void ras_set_start(struct inode *inode, struct ll_readahead_state *ras,
+ unsigned long index)
+{
+ ras->ras_window_start = index & (~(RAS_INCREASE_STEP(inode) - 1));
+}
+
+/* called with the ras_lock held or from places where it doesn't matter */
+static void ras_reset(struct inode *inode, struct ll_readahead_state *ras,
+ unsigned long index)
+{
+ ras->ras_last_readpage = index;
+ ras->ras_consecutive_requests = 0;
+ ras->ras_consecutive_pages = 0;
+ ras->ras_window_len = 0;
+ ras_set_start(inode, ras, index);
+ ras->ras_next_readahead = max(ras->ras_window_start, index);
+
+ RAS_CDEBUG(ras);
+}
+
+/* called with the ras_lock held or from places where it doesn't matter */
+static void ras_stride_reset(struct ll_readahead_state *ras)
+{
+ ras->ras_consecutive_stride_requests = 0;
+ ras->ras_stride_length = 0;
+ ras->ras_stride_pages = 0;
+ RAS_CDEBUG(ras);
+}
+
+void ll_readahead_init(struct inode *inode, struct ll_readahead_state *ras)
+{
+ spin_lock_init(&ras->ras_lock);
+ ras_reset(inode, ras, 0);
+ ras->ras_requests = 0;
+ INIT_LIST_HEAD(&ras->ras_read_beads);
+}
+
+/*
+ * Check whether the read request is in the stride window.
+ * If it is in the stride window, return 1, otherwise return 0.
+ */
+static int index_in_stride_window(struct ll_readahead_state *ras,
+ unsigned long index)
+{
+ unsigned long stride_gap;
+
+ if (ras->ras_stride_length == 0 || ras->ras_stride_pages == 0 ||
+ ras->ras_stride_pages == ras->ras_stride_length)
+ return 0;
+
+ stride_gap = index - ras->ras_last_readpage - 1;
+
+ /* If it is contiguous read */
+ if (stride_gap == 0)
+ return ras->ras_consecutive_pages + 1 <= ras->ras_stride_pages;
+
+ /* Otherwise check the stride by itself */
+ return (ras->ras_stride_length - ras->ras_stride_pages) == stride_gap &&
+ ras->ras_consecutive_pages == ras->ras_stride_pages;
+}
+
+static void ras_update_stride_detector(struct ll_readahead_state *ras,
+ unsigned long index)
+{
+ unsigned long stride_gap = index - ras->ras_last_readpage - 1;
+
+ if (!stride_io_mode(ras) && (stride_gap != 0 ||
+ ras->ras_consecutive_stride_requests == 0)) {
+ ras->ras_stride_pages = ras->ras_consecutive_pages;
+ ras->ras_stride_length = stride_gap +ras->ras_consecutive_pages;
+ }
+ LASSERT(ras->ras_request_index == 0);
+ LASSERT(ras->ras_consecutive_stride_requests == 0);
+
+ if (index <= ras->ras_last_readpage) {
+ /*Reset stride window for forward read*/
+ ras_stride_reset(ras);
+ return;
+ }
+
+ ras->ras_stride_pages = ras->ras_consecutive_pages;
+ ras->ras_stride_length = stride_gap +ras->ras_consecutive_pages;
+
+ RAS_CDEBUG(ras);
+ return;
+}
+
+static unsigned long
+stride_page_count(struct ll_readahead_state *ras, unsigned long len)
+{
+ return stride_pg_count(ras->ras_stride_offset, ras->ras_stride_length,
+ ras->ras_stride_pages, ras->ras_stride_offset,
+ len);
+}
+
+/* Stride Read-ahead window will be increased inc_len according to
+ * stride I/O pattern */
+static void ras_stride_increase_window(struct ll_readahead_state *ras,
+ struct ll_ra_info *ra,
+ unsigned long inc_len)
+{
+ unsigned long left, step, window_len;
+ unsigned long stride_len;
+
+ LASSERT(ras->ras_stride_length > 0);
+ LASSERTF(ras->ras_window_start + ras->ras_window_len
+ >= ras->ras_stride_offset, "window_start %lu, window_len %lu stride_offset %lu\n",
+ ras->ras_window_start,
+ ras->ras_window_len, ras->ras_stride_offset);
+
+ stride_len = ras->ras_window_start + ras->ras_window_len -
+ ras->ras_stride_offset;
+
+ left = stride_len % ras->ras_stride_length;
+ window_len = ras->ras_window_len - left;
+
+ if (left < ras->ras_stride_pages)
+ left += inc_len;
+ else
+ left = ras->ras_stride_pages + inc_len;
+
+ LASSERT(ras->ras_stride_pages != 0);
+
+ step = left / ras->ras_stride_pages;
+ left %= ras->ras_stride_pages;
+
+ window_len += step * ras->ras_stride_length + left;
+
+ if (stride_page_count(ras, window_len) <= ra->ra_max_pages_per_file)
+ ras->ras_window_len = window_len;
+
+ RAS_CDEBUG(ras);
+}
+
+static void ras_increase_window(struct inode *inode,
+ struct ll_readahead_state *ras,
+ struct ll_ra_info *ra)
+{
+ /* The stretch of ra-window should be aligned with max rpc_size
+ * but current clio architecture does not support retrieve such
+ * information from lower layer. FIXME later
+ */
+ if (stride_io_mode(ras))
+ ras_stride_increase_window(ras, ra, RAS_INCREASE_STEP(inode));
+ else
+ ras->ras_window_len = min(ras->ras_window_len +
+ RAS_INCREASE_STEP(inode),
+ ra->ra_max_pages_per_file);
+}
+
+void ras_update(struct ll_sb_info *sbi, struct inode *inode,
+ struct ll_readahead_state *ras, unsigned long index,
+ unsigned hit)
+{
+ struct ll_ra_info *ra = &sbi->ll_ra_info;
+ int zero = 0, stride_detect = 0, ra_miss = 0;
+
+ spin_lock(&ras->ras_lock);
+
+ ll_ra_stats_inc_sbi(sbi, hit ? RA_STAT_HIT : RA_STAT_MISS);
+
+ /* reset the read-ahead window in two cases. First when the app seeks
+ * or reads to some other part of the file. Secondly if we get a
+ * read-ahead miss that we think we've previously issued. This can
+ * be a symptom of there being so many read-ahead pages that the VM is
+ * reclaiming it before we get to it. */
+ if (!index_in_window(index, ras->ras_last_readpage, 8, 8)) {
+ zero = 1;
+ ll_ra_stats_inc_sbi(sbi, RA_STAT_DISTANT_READPAGE);
+ } else if (!hit && ras->ras_window_len &&
+ index < ras->ras_next_readahead &&
+ index_in_window(index, ras->ras_window_start, 0,
+ ras->ras_window_len)) {
+ ra_miss = 1;
+ ll_ra_stats_inc_sbi(sbi, RA_STAT_MISS_IN_WINDOW);
+ }
+
+ /* On the second access to a file smaller than the tunable
+ * ra_max_read_ahead_whole_pages trigger RA on all pages in the
+ * file up to ra_max_pages_per_file. This is simply a best effort
+ * and only occurs once per open file. Normal RA behavior is reverted
+ * to for subsequent IO. The mmap case does not increment
+ * ras_requests and thus can never trigger this behavior. */
+ if (ras->ras_requests == 2 && !ras->ras_request_index) {
+ __u64 kms_pages;
+
+ kms_pages = (i_size_read(inode) + PAGE_CACHE_SIZE - 1) >>
+ PAGE_CACHE_SHIFT;
+
+ CDEBUG(D_READA, "kmsp %llu mwp %lu mp %lu\n", kms_pages,
+ ra->ra_max_read_ahead_whole_pages, ra->ra_max_pages_per_file);
+
+ if (kms_pages &&
+ kms_pages <= ra->ra_max_read_ahead_whole_pages) {
+ ras->ras_window_start = 0;
+ ras->ras_last_readpage = 0;
+ ras->ras_next_readahead = 0;
+ ras->ras_window_len = min(ra->ra_max_pages_per_file,
+ ra->ra_max_read_ahead_whole_pages);
+ goto out_unlock;
+ }
+ }
+ if (zero) {
+ /* check whether it is in stride I/O mode*/
+ if (!index_in_stride_window(ras, index)) {
+ if (ras->ras_consecutive_stride_requests == 0 &&
+ ras->ras_request_index == 0) {
+ ras_update_stride_detector(ras, index);
+ ras->ras_consecutive_stride_requests++;
+ } else {
+ ras_stride_reset(ras);
+ }
+ ras_reset(inode, ras, index);
+ ras->ras_consecutive_pages++;
+ goto out_unlock;
+ } else {
+ ras->ras_consecutive_pages = 0;
+ ras->ras_consecutive_requests = 0;
+ if (++ras->ras_consecutive_stride_requests > 1)
+ stride_detect = 1;
+ RAS_CDEBUG(ras);
+ }
+ } else {
+ if (ra_miss) {
+ if (index_in_stride_window(ras, index) &&
+ stride_io_mode(ras)) {
+ /*If stride-RA hit cache miss, the stride dector
+ *will not be reset to avoid the overhead of
+ *redetecting read-ahead mode */
+ if (index != ras->ras_last_readpage + 1)
+ ras->ras_consecutive_pages = 0;
+ ras_reset(inode, ras, index);
+ RAS_CDEBUG(ras);
+ } else {
+ /* Reset both stride window and normal RA
+ * window */
+ ras_reset(inode, ras, index);
+ ras->ras_consecutive_pages++;
+ ras_stride_reset(ras);
+ goto out_unlock;
+ }
+ } else if (stride_io_mode(ras)) {
+ /* If this is contiguous read but in stride I/O mode
+ * currently, check whether stride step still is valid,
+ * if invalid, it will reset the stride ra window*/
+ if (!index_in_stride_window(ras, index)) {
+ /* Shrink stride read-ahead window to be zero */
+ ras_stride_reset(ras);
+ ras->ras_window_len = 0;
+ ras->ras_next_readahead = index;
+ }
+ }
+ }
+ ras->ras_consecutive_pages++;
+ ras->ras_last_readpage = index;
+ ras_set_start(inode, ras, index);
+
+ if (stride_io_mode(ras))
+ /* Since stride readahead is sensitive to the offset
+ * of read-ahead, so we use original offset here,
+ * instead of ras_window_start, which is RPC aligned */
+ ras->ras_next_readahead = max(index, ras->ras_next_readahead);
+ else
+ ras->ras_next_readahead = max(ras->ras_window_start,
+ ras->ras_next_readahead);
+ RAS_CDEBUG(ras);
+
+ /* Trigger RA in the mmap case where ras_consecutive_requests
+ * is not incremented and thus can't be used to trigger RA */
+ if (!ras->ras_window_len && ras->ras_consecutive_pages == 4) {
+ ras->ras_window_len = RAS_INCREASE_STEP(inode);
+ goto out_unlock;
+ }
+
+ /* Initially reset the stride window offset to next_readahead*/
+ if (ras->ras_consecutive_stride_requests == 2 && stride_detect) {
+ /**
+ * Once stride IO mode is detected, next_readahead should be
+ * reset to make sure next_readahead > stride offset
+ */
+ ras->ras_next_readahead = max(index, ras->ras_next_readahead);
+ ras->ras_stride_offset = index;
+ ras->ras_window_len = RAS_INCREASE_STEP(inode);
+ }
+
+ /* The initial ras_window_len is set to the request size. To avoid
+ * uselessly reading and discarding pages for random IO the window is
+ * only increased once per consecutive request received. */
+ if ((ras->ras_consecutive_requests > 1 || stride_detect) &&
+ !ras->ras_request_index)
+ ras_increase_window(inode, ras, ra);
+out_unlock:
+ RAS_CDEBUG(ras);
+ ras->ras_request_index++;
+ spin_unlock(&ras->ras_lock);
+ return;
+}
+
+int ll_writepage(struct page *vmpage, struct writeback_control *wbc)
+{
+ struct inode *inode = vmpage->mapping->host;
+ struct ll_inode_info *lli = ll_i2info(inode);
+ struct lu_env *env;
+ struct cl_io *io;
+ struct cl_page *page;
+ struct cl_object *clob;
+ struct cl_env_nest nest;
+ bool redirtied = false;
+ bool unlocked = false;
+ int result;
+
+ LASSERT(PageLocked(vmpage));
+ LASSERT(!PageWriteback(vmpage));
+
+ LASSERT(ll_i2dtexp(inode) != NULL);
+
+ env = cl_env_nested_get(&nest);
+ if (IS_ERR(env)) {
+ result = PTR_ERR(env);
+ goto out;
+ }
+
+ clob = ll_i2info(inode)->lli_clob;
+ LASSERT(clob != NULL);
+
+ io = ccc_env_thread_io(env);
+ io->ci_obj = clob;
+ io->ci_ignore_layout = 1;
+ result = cl_io_init(env, io, CIT_MISC, clob);
+ if (result == 0) {
+ page = cl_page_find(env, clob, vmpage->index,
+ vmpage, CPT_CACHEABLE);
+ if (!IS_ERR(page)) {
+ lu_ref_add(&page->cp_reference, "writepage",
+ current);
+ cl_page_assume(env, io, page);
+ result = cl_page_flush(env, io, page);
+ if (result != 0) {
+ /*
+ * Re-dirty page on error so it retries write,
+ * but not in case when IO has actually
+ * occurred and completed with an error.
+ */
+ if (!PageError(vmpage)) {
+ redirty_page_for_writepage(wbc, vmpage);
+ result = 0;
+ redirtied = true;
+ }
+ }
+ cl_page_disown(env, io, page);
+ unlocked = true;
+ lu_ref_del(&page->cp_reference,
+ "writepage", current);
+ cl_page_put(env, page);
+ } else {
+ result = PTR_ERR(page);
+ }
+ }
+ cl_io_fini(env, io);
+
+ if (redirtied && wbc->sync_mode == WB_SYNC_ALL) {
+ loff_t offset = cl_offset(clob, vmpage->index);
+
+ /* Flush page failed because the extent is being written out.
+ * Wait for the write of extent to be finished to avoid
+ * breaking kernel which assumes ->writepage should mark
+ * PageWriteback or clean the page. */
+ result = cl_sync_file_range(inode, offset,
+ offset + PAGE_CACHE_SIZE - 1,
+ CL_FSYNC_LOCAL, 1);
+ if (result > 0) {
+ /* actually we may have written more than one page.
+ * decreasing this page because the caller will count
+ * it. */
+ wbc->nr_to_write -= result - 1;
+ result = 0;
+ }
+ }
+
+ cl_env_nested_put(&nest, env);
+ goto out;
+
+out:
+ if (result < 0) {
+ if (!lli->lli_async_rc)
+ lli->lli_async_rc = result;
+ SetPageError(vmpage);
+ if (!unlocked)
+ unlock_page(vmpage);
+ }
+ return result;
+}
+
+int ll_writepages(struct address_space *mapping, struct writeback_control *wbc)
+{
+ struct inode *inode = mapping->host;
+ struct ll_sb_info *sbi = ll_i2sbi(inode);
+ loff_t start;
+ loff_t end;
+ enum cl_fsync_mode mode;
+ int range_whole = 0;
+ int result;
+ int ignore_layout = 0;
+
+ if (wbc->range_cyclic) {
+ start = mapping->writeback_index << PAGE_CACHE_SHIFT;
+ end = OBD_OBJECT_EOF;
+ } else {
+ start = wbc->range_start;
+ end = wbc->range_end;
+ if (end == LLONG_MAX) {
+ end = OBD_OBJECT_EOF;
+ range_whole = start == 0;
+ }
+ }
+
+ mode = CL_FSYNC_NONE;
+ if (wbc->sync_mode == WB_SYNC_ALL)
+ mode = CL_FSYNC_LOCAL;
+
+ if (sbi->ll_umounting)
+ /* if the mountpoint is being umounted, all pages have to be
+ * evicted to avoid hitting LBUG when truncate_inode_pages()
+ * is called later on. */
+ ignore_layout = 1;
+ result = cl_sync_file_range(inode, start, end, mode, ignore_layout);
+ if (result > 0) {
+ wbc->nr_to_write -= result;
+ result = 0;
+ }
+
+ if (wbc->range_cyclic || (range_whole && wbc->nr_to_write > 0)) {
+ if (end == OBD_OBJECT_EOF)
+ end = i_size_read(inode);
+ mapping->writeback_index = (end >> PAGE_CACHE_SHIFT) + 1;
+ }
+ return result;
+}
+
+int ll_readpage(struct file *file, struct page *vmpage)
+{
+ struct ll_cl_context *lcc;
+ int result;
+
+ lcc = ll_cl_init(file, vmpage, 0);
+ if (!IS_ERR(lcc)) {
+ struct lu_env *env = lcc->lcc_env;
+ struct cl_io *io = lcc->lcc_io;
+ struct cl_page *page = lcc->lcc_page;
+
+ LASSERT(page->cp_type == CPT_CACHEABLE);
+ if (likely(!PageUptodate(vmpage))) {
+ cl_page_assume(env, io, page);
+ result = cl_io_read_page(env, io, page);
+ } else {
+ /* Page from a non-object file. */
+ unlock_page(vmpage);
+ result = 0;
+ }
+ ll_cl_fini(lcc);
+ } else {
+ unlock_page(vmpage);
+ result = PTR_ERR(lcc);
+ }
+ return result;
+}
Code Review / kvmfornfv.git / blobdiff