diff options
Diffstat (limited to 'drivers/staging/lustre/lustre/llite/rw.c')
| -rw-r--r-- | drivers/staging/lustre/lustre/llite/rw.c | 1314 |
1 files changed, 1314 insertions, 0 deletions
diff --git a/drivers/staging/lustre/lustre/llite/rw.c b/drivers/staging/lustre/lustre/llite/rw.c new file mode 100644 index 000000000000..fac117889011 --- /dev/null +++ b/drivers/staging/lustre/lustre/llite/rw.c @@ -0,0 +1,1314 @@ +/* + * 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 <asm/uaccess.h> + +#include <linux/fs.h> +#include <linux/stat.h> +#include <asm/uaccess.h> +#include <linux/mm.h> +#include <linux/pagemap.h> +/* current_is_kswapd() */ +#include <linux/swap.h> + +#define DEBUG_SUBSYSTEM S_LLITE + +#include <lustre_lite.h> +#include <obd_cksum.h> +#include "llite_internal.h" +#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); + } + + if (io && lcc->lcc_created) { + cl_io_end(env, io); + cl_io_unlock(env, io); + cl_io_iter_fini(env, io); + cl_io_fini(env, io); + } + 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_PTR(PTR_ERR(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 dirting page w/o inode lock, this" + "will break truncate.\n", current->comm); + libcfs_debug_dumpstack(NULL); + LBUG(); + return ERR_PTR(-EIO); + } + + /* + * Loop-back driver calls ->prepare_write() and ->sendfile() + * 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_iov = NULL; + cio->cui_nrsegs = 0; + 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_created = 1; + } + + 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; + ENTRY; + + 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; + ENTRY; + + 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; + ENTRY; + + /* 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)) + GOTO(out, ret = 0); + + /* 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; + + ENTRY; + + 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 */ + unsigned int gfp_mask; + int rc = 0; + const char *msg = NULL; + + ENTRY; + + gfp_mask = GFP_HIGHUSER & ~__GFP_WAIT; +#ifdef __GFP_NOWARN + gfp_mask |= __GFP_NOWARN; +#endif + 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)). + * Temprarily 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 siginificantly. 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_lengh = 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 "LPU64", end "LPU64" 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; + ENTRY; + + 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; + ENTRY; + + 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 "LPU64" 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, 0); + } + } + 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, 0); + } 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, 0); + } + } 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 sentivite 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, 0); + } + + /* 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); + EXIT; +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; + ENTRY; + + LASSERT(PageLocked(vmpage)); + LASSERT(!PageWriteback(vmpage)); + + LASSERT(ll_i2dtexp(inode) != NULL); + + env = cl_env_nested_get(&nest); + if (IS_ERR(env)) + GOTO(out, result = PTR_ERR(env)); + + 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, result); + +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; + ENTRY; + + 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; + ENTRY; + + 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); +} |