--- /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) 2008, 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.
+ */
+
+#include <linux/fs.h>
+#include <linux/sched.h>
+#include <linux/mm.h>
+#include <linux/highmem.h>
+#include <linux/pagemap.h>
+
+#define DEBUG_SUBSYSTEM S_LLITE
+
+#include "../include/obd_support.h"
+#include "../include/lustre_lite.h"
+#include "../include/lustre_dlm.h"
+#include "llite_internal.h"
+
+#define SA_OMITTED_ENTRY_MAX 8ULL
+
+typedef enum {
+ /** negative values are for error cases */
+ SA_ENTRY_INIT = 0, /** init entry */
+ SA_ENTRY_SUCC = 1, /** stat succeed */
+ SA_ENTRY_INVA = 2, /** invalid entry */
+ SA_ENTRY_DEST = 3, /** entry to be destroyed */
+} se_stat_t;
+
+struct ll_sa_entry {
+ /* link into sai->sai_entries */
+ struct list_head se_link;
+ /* link into sai->sai_entries_{received,stated} */
+ struct list_head se_list;
+ /* link into sai hash table locally */
+ struct list_head se_hash;
+ /* entry reference count */
+ atomic_t se_refcount;
+ /* entry index in the sai */
+ __u64 se_index;
+ /* low layer ldlm lock handle */
+ __u64 se_handle;
+ /* entry status */
+ se_stat_t se_stat;
+ /* entry size, contains name */
+ int se_size;
+ /* pointer to async getattr enqueue info */
+ struct md_enqueue_info *se_minfo;
+ /* pointer to the async getattr request */
+ struct ptlrpc_request *se_req;
+ /* pointer to the target inode */
+ struct inode *se_inode;
+ /* entry name */
+ struct qstr se_qstr;
+};
+
+static unsigned int sai_generation;
+static DEFINE_SPINLOCK(sai_generation_lock);
+
+static inline int ll_sa_entry_unhashed(struct ll_sa_entry *entry)
+{
+ return list_empty(&entry->se_hash);
+}
+
+/*
+ * The entry only can be released by the caller, it is necessary to hold lock.
+ */
+static inline int ll_sa_entry_stated(struct ll_sa_entry *entry)
+{
+ smp_rmb();
+ return (entry->se_stat != SA_ENTRY_INIT);
+}
+
+static inline int ll_sa_entry_hash(int val)
+{
+ return val & LL_SA_CACHE_MASK;
+}
+
+/*
+ * Insert entry to hash SA table.
+ */
+static inline void
+ll_sa_entry_enhash(struct ll_statahead_info *sai, struct ll_sa_entry *entry)
+{
+ int i = ll_sa_entry_hash(entry->se_qstr.hash);
+
+ spin_lock(&sai->sai_cache_lock[i]);
+ list_add_tail(&entry->se_hash, &sai->sai_cache[i]);
+ spin_unlock(&sai->sai_cache_lock[i]);
+}
+
+/*
+ * Remove entry from SA table.
+ */
+static inline void
+ll_sa_entry_unhash(struct ll_statahead_info *sai, struct ll_sa_entry *entry)
+{
+ int i = ll_sa_entry_hash(entry->se_qstr.hash);
+
+ spin_lock(&sai->sai_cache_lock[i]);
+ list_del_init(&entry->se_hash);
+ spin_unlock(&sai->sai_cache_lock[i]);
+}
+
+static inline int agl_should_run(struct ll_statahead_info *sai,
+ struct inode *inode)
+{
+ return (inode != NULL && S_ISREG(inode->i_mode) && sai->sai_agl_valid);
+}
+
+static inline struct ll_sa_entry *
+sa_first_received_entry(struct ll_statahead_info *sai)
+{
+ return list_entry(sai->sai_entries_received.next,
+ struct ll_sa_entry, se_list);
+}
+
+static inline struct ll_inode_info *
+agl_first_entry(struct ll_statahead_info *sai)
+{
+ return list_entry(sai->sai_entries_agl.next,
+ struct ll_inode_info, lli_agl_list);
+}
+
+static inline int sa_sent_full(struct ll_statahead_info *sai)
+{
+ return atomic_read(&sai->sai_cache_count) >= sai->sai_max;
+}
+
+static inline int sa_received_empty(struct ll_statahead_info *sai)
+{
+ return list_empty(&sai->sai_entries_received);
+}
+
+static inline int agl_list_empty(struct ll_statahead_info *sai)
+{
+ return list_empty(&sai->sai_entries_agl);
+}
+
+/**
+ * (1) hit ratio less than 80%
+ * or
+ * (2) consecutive miss more than 8
+ * then means low hit.
+ */
+static inline int sa_low_hit(struct ll_statahead_info *sai)
+{
+ return ((sai->sai_hit > 7 && sai->sai_hit < 4 * sai->sai_miss) ||
+ (sai->sai_consecutive_miss > 8));
+}
+
+/*
+ * If the given index is behind of statahead window more than
+ * SA_OMITTED_ENTRY_MAX, then it is old.
+ */
+static inline int is_omitted_entry(struct ll_statahead_info *sai, __u64 index)
+{
+ return ((__u64)sai->sai_max + index + SA_OMITTED_ENTRY_MAX <
+ sai->sai_index);
+}
+
+/*
+ * Insert it into sai_entries tail when init.
+ */
+static struct ll_sa_entry *
+ll_sa_entry_alloc(struct ll_statahead_info *sai, __u64 index,
+ const char *name, int len)
+{
+ struct ll_inode_info *lli;
+ struct ll_sa_entry *entry;
+ int entry_size;
+ char *dname;
+
+ entry_size = sizeof(struct ll_sa_entry) + (len & ~3) + 4;
+ entry = kzalloc(entry_size, GFP_NOFS);
+ if (unlikely(!entry))
+ return ERR_PTR(-ENOMEM);
+
+ CDEBUG(D_READA, "alloc sa entry %.*s(%p) index %llu\n",
+ len, name, entry, index);
+
+ entry->se_index = index;
+
+ /*
+ * Statahead entry reference rules:
+ *
+ * 1) When statahead entry is initialized, its reference is set as 2.
+ * One reference is used by the directory scanner. When the scanner
+ * searches the statahead cache for the given name, it can perform
+ * lockless hash lookup (only the scanner can remove entry from hash
+ * list), and once found, it needn't to call "atomic_inc()" for the
+ * entry reference. So the performance is improved. After using the
+ * statahead entry, the scanner will call "atomic_dec()" to drop the
+ * reference held when initialization. If it is the last reference,
+ * the statahead entry will be freed.
+ *
+ * 2) All other threads, including statahead thread and ptlrpcd thread,
+ * when they process the statahead entry, the reference for target
+ * should be held to guarantee the entry will not be released by the
+ * directory scanner. After processing the entry, these threads will
+ * drop the entry reference. If it is the last reference, the entry
+ * will be freed.
+ *
+ * The second reference when initializes the statahead entry is used
+ * by the statahead thread, following the rule 2).
+ */
+ atomic_set(&entry->se_refcount, 2);
+ entry->se_stat = SA_ENTRY_INIT;
+ entry->se_size = entry_size;
+ dname = (char *)entry + sizeof(struct ll_sa_entry);
+ memcpy(dname, name, len);
+ dname[len] = 0;
+ entry->se_qstr.hash = full_name_hash(name, len);
+ entry->se_qstr.len = len;
+ entry->se_qstr.name = dname;
+
+ lli = ll_i2info(sai->sai_inode);
+ spin_lock(&lli->lli_sa_lock);
+ list_add_tail(&entry->se_link, &sai->sai_entries);
+ INIT_LIST_HEAD(&entry->se_list);
+ ll_sa_entry_enhash(sai, entry);
+ spin_unlock(&lli->lli_sa_lock);
+
+ atomic_inc(&sai->sai_cache_count);
+
+ return entry;
+}
+
+/*
+ * Used by the directory scanner to search entry with name.
+ *
+ * Only the caller can remove the entry from hash, so it is unnecessary to hold
+ * hash lock. It is caller's duty to release the init refcount on the entry, so
+ * it is also unnecessary to increase refcount on the entry.
+ */
+static struct ll_sa_entry *
+ll_sa_entry_get_byname(struct ll_statahead_info *sai, const struct qstr *qstr)
+{
+ struct ll_sa_entry *entry;
+ int i = ll_sa_entry_hash(qstr->hash);
+
+ list_for_each_entry(entry, &sai->sai_cache[i], se_hash) {
+ if (entry->se_qstr.hash == qstr->hash &&
+ entry->se_qstr.len == qstr->len &&
+ memcmp(entry->se_qstr.name, qstr->name, qstr->len) == 0)
+ return entry;
+ }
+ return NULL;
+}
+
+/*
+ * Used by the async getattr request callback to find entry with index.
+ *
+ * Inside lli_sa_lock to prevent others to change the list during the search.
+ * It needs to increase entry refcount before returning to guarantee that the
+ * entry cannot be freed by others.
+ */
+static struct ll_sa_entry *
+ll_sa_entry_get_byindex(struct ll_statahead_info *sai, __u64 index)
+{
+ struct ll_sa_entry *entry;
+
+ list_for_each_entry(entry, &sai->sai_entries, se_link) {
+ if (entry->se_index == index) {
+ LASSERT(atomic_read(&entry->se_refcount) > 0);
+ atomic_inc(&entry->se_refcount);
+ return entry;
+ }
+ if (entry->se_index > index)
+ break;
+ }
+ return NULL;
+}
+
+static void ll_sa_entry_cleanup(struct ll_statahead_info *sai,
+ struct ll_sa_entry *entry)
+{
+ struct md_enqueue_info *minfo = entry->se_minfo;
+ struct ptlrpc_request *req = entry->se_req;
+
+ if (minfo) {
+ entry->se_minfo = NULL;
+ ll_intent_release(&minfo->mi_it);
+ iput(minfo->mi_dir);
+ OBD_FREE_PTR(minfo);
+ }
+
+ if (req) {
+ entry->se_req = NULL;
+ ptlrpc_req_finished(req);
+ }
+}
+
+static void ll_sa_entry_put(struct ll_statahead_info *sai,
+ struct ll_sa_entry *entry)
+{
+ if (atomic_dec_and_test(&entry->se_refcount)) {
+ CDEBUG(D_READA, "free sa entry %.*s(%p) index %llu\n",
+ entry->se_qstr.len, entry->se_qstr.name, entry,
+ entry->se_index);
+
+ LASSERT(list_empty(&entry->se_link));
+ LASSERT(list_empty(&entry->se_list));
+ LASSERT(ll_sa_entry_unhashed(entry));
+
+ ll_sa_entry_cleanup(sai, entry);
+ iput(entry->se_inode);
+
+ OBD_FREE(entry, entry->se_size);
+ atomic_dec(&sai->sai_cache_count);
+ }
+}
+
+static inline void
+do_sa_entry_fini(struct ll_statahead_info *sai, struct ll_sa_entry *entry)
+{
+ struct ll_inode_info *lli = ll_i2info(sai->sai_inode);
+
+ LASSERT(!ll_sa_entry_unhashed(entry));
+ LASSERT(!list_empty(&entry->se_link));
+
+ ll_sa_entry_unhash(sai, entry);
+
+ spin_lock(&lli->lli_sa_lock);
+ entry->se_stat = SA_ENTRY_DEST;
+ list_del_init(&entry->se_link);
+ if (likely(!list_empty(&entry->se_list)))
+ list_del_init(&entry->se_list);
+ spin_unlock(&lli->lli_sa_lock);
+
+ ll_sa_entry_put(sai, entry);
+}
+
+/*
+ * Delete it from sai_entries_stated list when fini.
+ */
+static void
+ll_sa_entry_fini(struct ll_statahead_info *sai, struct ll_sa_entry *entry)
+{
+ struct ll_sa_entry *pos, *next;
+
+ if (entry)
+ do_sa_entry_fini(sai, entry);
+
+ /* drop old entry, only 'scanner' process does this, no need to lock */
+ list_for_each_entry_safe(pos, next, &sai->sai_entries, se_link) {
+ if (!is_omitted_entry(sai, pos->se_index))
+ break;
+ do_sa_entry_fini(sai, pos);
+ }
+}
+
+/*
+ * Inside lli_sa_lock.
+ */
+static void
+do_sa_entry_to_stated(struct ll_statahead_info *sai,
+ struct ll_sa_entry *entry, se_stat_t stat)
+{
+ struct ll_sa_entry *se;
+ struct list_head *pos = &sai->sai_entries_stated;
+
+ if (!list_empty(&entry->se_list))
+ list_del_init(&entry->se_list);
+
+ list_for_each_entry_reverse(se, &sai->sai_entries_stated, se_list) {
+ if (se->se_index < entry->se_index) {
+ pos = &se->se_list;
+ break;
+ }
+ }
+
+ list_add(&entry->se_list, pos);
+ entry->se_stat = stat;
+}
+
+/*
+ * Move entry to sai_entries_stated and sort with the index.
+ * \retval 1 -- entry to be destroyed.
+ * \retval 0 -- entry is inserted into stated list.
+ */
+static int
+ll_sa_entry_to_stated(struct ll_statahead_info *sai,
+ struct ll_sa_entry *entry, se_stat_t stat)
+{
+ struct ll_inode_info *lli = ll_i2info(sai->sai_inode);
+ int ret = 1;
+
+ ll_sa_entry_cleanup(sai, entry);
+
+ spin_lock(&lli->lli_sa_lock);
+ if (likely(entry->se_stat != SA_ENTRY_DEST)) {
+ do_sa_entry_to_stated(sai, entry, stat);
+ ret = 0;
+ }
+ spin_unlock(&lli->lli_sa_lock);
+
+ return ret;
+}
+
+/*
+ * Insert inode into the list of sai_entries_agl.
+ */
+static void ll_agl_add(struct ll_statahead_info *sai,
+ struct inode *inode, int index)
+{
+ struct ll_inode_info *child = ll_i2info(inode);
+ struct ll_inode_info *parent = ll_i2info(sai->sai_inode);
+ int added = 0;
+
+ spin_lock(&child->lli_agl_lock);
+ if (child->lli_agl_index == 0) {
+ child->lli_agl_index = index;
+ spin_unlock(&child->lli_agl_lock);
+
+ LASSERT(list_empty(&child->lli_agl_list));
+
+ igrab(inode);
+ spin_lock(&parent->lli_agl_lock);
+ if (agl_list_empty(sai))
+ added = 1;
+ list_add_tail(&child->lli_agl_list, &sai->sai_entries_agl);
+ spin_unlock(&parent->lli_agl_lock);
+ } else {
+ spin_unlock(&child->lli_agl_lock);
+ }
+
+ if (added > 0)
+ wake_up(&sai->sai_agl_thread.t_ctl_waitq);
+}
+
+static struct ll_statahead_info *ll_sai_alloc(void)
+{
+ struct ll_statahead_info *sai;
+ int i;
+
+ sai = kzalloc(sizeof(*sai), GFP_NOFS);
+ if (!sai)
+ return NULL;
+
+ atomic_set(&sai->sai_refcount, 1);
+
+ spin_lock(&sai_generation_lock);
+ sai->sai_generation = ++sai_generation;
+ if (unlikely(sai_generation == 0))
+ sai->sai_generation = ++sai_generation;
+ spin_unlock(&sai_generation_lock);
+
+ sai->sai_max = LL_SA_RPC_MIN;
+ sai->sai_index = 1;
+ init_waitqueue_head(&sai->sai_waitq);
+ init_waitqueue_head(&sai->sai_thread.t_ctl_waitq);
+ init_waitqueue_head(&sai->sai_agl_thread.t_ctl_waitq);
+
+ INIT_LIST_HEAD(&sai->sai_entries);
+ INIT_LIST_HEAD(&sai->sai_entries_received);
+ INIT_LIST_HEAD(&sai->sai_entries_stated);
+ INIT_LIST_HEAD(&sai->sai_entries_agl);
+
+ for (i = 0; i < LL_SA_CACHE_SIZE; i++) {
+ INIT_LIST_HEAD(&sai->sai_cache[i]);
+ spin_lock_init(&sai->sai_cache_lock[i]);
+ }
+ atomic_set(&sai->sai_cache_count, 0);
+
+ return sai;
+}
+
+static inline struct ll_statahead_info *
+ll_sai_get(struct ll_statahead_info *sai)
+{
+ atomic_inc(&sai->sai_refcount);
+ return sai;
+}
+
+static void ll_sai_put(struct ll_statahead_info *sai)
+{
+ struct inode *inode = sai->sai_inode;
+ struct ll_inode_info *lli = ll_i2info(inode);
+
+ if (atomic_dec_and_lock(&sai->sai_refcount, &lli->lli_sa_lock)) {
+ struct ll_sa_entry *entry, *next;
+
+ if (unlikely(atomic_read(&sai->sai_refcount) > 0)) {
+ /* It is race case, the interpret callback just hold
+ * a reference count */
+ spin_unlock(&lli->lli_sa_lock);
+ return;
+ }
+
+ LASSERT(lli->lli_opendir_key == NULL);
+ LASSERT(thread_is_stopped(&sai->sai_thread));
+ LASSERT(thread_is_stopped(&sai->sai_agl_thread));
+
+ lli->lli_sai = NULL;
+ lli->lli_opendir_pid = 0;
+ spin_unlock(&lli->lli_sa_lock);
+
+ if (sai->sai_sent > sai->sai_replied)
+ CDEBUG(D_READA, "statahead for dir "DFID
+ " does not finish: [sent:%llu] [replied:%llu]\n",
+ PFID(&lli->lli_fid),
+ sai->sai_sent, sai->sai_replied);
+
+ list_for_each_entry_safe(entry, next,
+ &sai->sai_entries, se_link)
+ do_sa_entry_fini(sai, entry);
+
+ LASSERT(list_empty(&sai->sai_entries));
+ LASSERT(sa_received_empty(sai));
+ LASSERT(list_empty(&sai->sai_entries_stated));
+
+ LASSERT(atomic_read(&sai->sai_cache_count) == 0);
+ LASSERT(agl_list_empty(sai));
+
+ iput(inode);
+ OBD_FREE_PTR(sai);
+ }
+}
+
+/* Do NOT forget to drop inode refcount when into sai_entries_agl. */
+static void ll_agl_trigger(struct inode *inode, struct ll_statahead_info *sai)
+{
+ struct ll_inode_info *lli = ll_i2info(inode);
+ __u64 index = lli->lli_agl_index;
+ int rc;
+
+ LASSERT(list_empty(&lli->lli_agl_list));
+
+ /* AGL maybe fall behind statahead with one entry */
+ if (is_omitted_entry(sai, index + 1)) {
+ lli->lli_agl_index = 0;
+ iput(inode);
+ return;
+ }
+
+ /* Someone is in glimpse (sync or async), do nothing. */
+ rc = down_write_trylock(&lli->lli_glimpse_sem);
+ if (rc == 0) {
+ lli->lli_agl_index = 0;
+ iput(inode);
+ return;
+ }
+
+ /*
+ * Someone triggered glimpse within 1 sec before.
+ * 1) The former glimpse succeeded with glimpse lock granted by OST, and
+ * if the lock is still cached on client, AGL needs to do nothing. If
+ * it is cancelled by other client, AGL maybe cannot obtain new lock
+ * for no glimpse callback triggered by AGL.
+ * 2) The former glimpse succeeded, but OST did not grant glimpse lock.
+ * Under such case, it is quite possible that the OST will not grant
+ * glimpse lock for AGL also.
+ * 3) The former glimpse failed, compared with other two cases, it is
+ * relative rare. AGL can ignore such case, and it will not muchly
+ * affect the performance.
+ */
+ if (lli->lli_glimpse_time != 0 &&
+ time_before(cfs_time_shift(-1), lli->lli_glimpse_time)) {
+ up_write(&lli->lli_glimpse_sem);
+ lli->lli_agl_index = 0;
+ iput(inode);
+ return;
+ }
+
+ CDEBUG(D_READA, "Handling (init) async glimpse: inode = "
+ DFID", idx = %llu\n", PFID(&lli->lli_fid), index);
+
+ cl_agl(inode);
+ lli->lli_agl_index = 0;
+ lli->lli_glimpse_time = cfs_time_current();
+ up_write(&lli->lli_glimpse_sem);
+
+ CDEBUG(D_READA, "Handled (init) async glimpse: inode= "
+ DFID", idx = %llu, rc = %d\n",
+ PFID(&lli->lli_fid), index, rc);
+
+ iput(inode);
+}
+
+static void ll_post_statahead(struct ll_statahead_info *sai)
+{
+ struct inode *dir = sai->sai_inode;
+ struct inode *child;
+ struct ll_inode_info *lli = ll_i2info(dir);
+ struct ll_sa_entry *entry;
+ struct md_enqueue_info *minfo;
+ struct lookup_intent *it;
+ struct ptlrpc_request *req;
+ struct mdt_body *body;
+ int rc = 0;
+
+ spin_lock(&lli->lli_sa_lock);
+ if (unlikely(sa_received_empty(sai))) {
+ spin_unlock(&lli->lli_sa_lock);
+ return;
+ }
+ entry = sa_first_received_entry(sai);
+ atomic_inc(&entry->se_refcount);
+ list_del_init(&entry->se_list);
+ spin_unlock(&lli->lli_sa_lock);
+
+ LASSERT(entry->se_handle != 0);
+
+ minfo = entry->se_minfo;
+ it = &minfo->mi_it;
+ req = entry->se_req;
+ body = req_capsule_server_get(&req->rq_pill, &RMF_MDT_BODY);
+ if (body == NULL) {
+ rc = -EFAULT;
+ goto out;
+ }
+
+ child = entry->se_inode;
+ if (child == NULL) {
+ /*
+ * lookup.
+ */
+ LASSERT(fid_is_zero(&minfo->mi_data.op_fid2));
+
+ /* XXX: No fid in reply, this is probably cross-ref case.
+ * SA can't handle it yet. */
+ if (body->valid & OBD_MD_MDS) {
+ rc = -EAGAIN;
+ goto out;
+ }
+ } else {
+ /*
+ * revalidate.
+ */
+ /* unlinked and re-created with the same name */
+ if (unlikely(!lu_fid_eq(&minfo->mi_data.op_fid2, &body->fid1))){
+ entry->se_inode = NULL;
+ iput(child);
+ child = NULL;
+ }
+ }
+
+ it->d.lustre.it_lock_handle = entry->se_handle;
+ rc = md_revalidate_lock(ll_i2mdexp(dir), it, ll_inode2fid(dir), NULL);
+ if (rc != 1) {
+ rc = -EAGAIN;
+ goto out;
+ }
+
+ rc = ll_prep_inode(&child, req, dir->i_sb, it);
+ if (rc)
+ goto out;
+
+ CDEBUG(D_DLMTRACE, "setting l_data to inode %p (%lu/%u)\n",
+ child, child->i_ino, child->i_generation);
+ ll_set_lock_data(ll_i2sbi(dir)->ll_md_exp, child, it, NULL);
+
+ entry->se_inode = child;
+
+ if (agl_should_run(sai, child))
+ ll_agl_add(sai, child, entry->se_index);
+
+out:
+ /* The "ll_sa_entry_to_stated()" will drop related ldlm ibits lock
+ * reference count by calling "ll_intent_drop_lock()" in spite of the
+ * above operations failed or not. Do not worry about calling
+ * "ll_intent_drop_lock()" more than once. */
+ rc = ll_sa_entry_to_stated(sai, entry,
+ rc < 0 ? SA_ENTRY_INVA : SA_ENTRY_SUCC);
+ if (rc == 0 && entry->se_index == sai->sai_index_wait)
+ wake_up(&sai->sai_waitq);
+ ll_sa_entry_put(sai, entry);
+}
+
+static int ll_statahead_interpret(struct ptlrpc_request *req,
+ struct md_enqueue_info *minfo, int rc)
+{
+ struct lookup_intent *it = &minfo->mi_it;
+ struct inode *dir = minfo->mi_dir;
+ struct ll_inode_info *lli = ll_i2info(dir);
+ struct ll_statahead_info *sai = NULL;
+ struct ll_sa_entry *entry;
+ __u64 handle = 0;
+ int wakeup;
+
+ if (it_disposition(it, DISP_LOOKUP_NEG))
+ rc = -ENOENT;
+
+ if (rc == 0) {
+ /* release ibits lock ASAP to avoid deadlock when statahead
+ * thread enqueues lock on parent in readdir and another
+ * process enqueues lock on child with parent lock held, eg.
+ * unlink. */
+ handle = it->d.lustre.it_lock_handle;
+ ll_intent_drop_lock(it);
+ }
+
+ spin_lock(&lli->lli_sa_lock);
+ /* stale entry */
+ if (unlikely(lli->lli_sai == NULL ||
+ lli->lli_sai->sai_generation != minfo->mi_generation)) {
+ spin_unlock(&lli->lli_sa_lock);
+ rc = -ESTALE;
+ goto out;
+ } else {
+ sai = ll_sai_get(lli->lli_sai);
+ if (unlikely(!thread_is_running(&sai->sai_thread))) {
+ sai->sai_replied++;
+ spin_unlock(&lli->lli_sa_lock);
+ rc = -EBADFD;
+ goto out;
+ }
+
+ entry = ll_sa_entry_get_byindex(sai, minfo->mi_cbdata);
+ if (entry == NULL) {
+ sai->sai_replied++;
+ spin_unlock(&lli->lli_sa_lock);
+ rc = -EIDRM;
+ goto out;
+ }
+
+ if (rc != 0) {
+ do_sa_entry_to_stated(sai, entry, SA_ENTRY_INVA);
+ wakeup = (entry->se_index == sai->sai_index_wait);
+ } else {
+ entry->se_minfo = minfo;
+ entry->se_req = ptlrpc_request_addref(req);
+ /* Release the async ibits lock ASAP to avoid deadlock
+ * when statahead thread tries to enqueue lock on parent
+ * for readpage and other tries to enqueue lock on child
+ * with parent's lock held, for example: unlink. */
+ entry->se_handle = handle;
+ wakeup = sa_received_empty(sai);
+ list_add_tail(&entry->se_list,
+ &sai->sai_entries_received);
+ }
+ sai->sai_replied++;
+ spin_unlock(&lli->lli_sa_lock);
+
+ ll_sa_entry_put(sai, entry);
+ if (wakeup)
+ wake_up(&sai->sai_thread.t_ctl_waitq);
+ }
+
+out:
+ if (rc != 0) {
+ ll_intent_release(it);
+ iput(dir);
+ OBD_FREE_PTR(minfo);
+ }
+ if (sai != NULL)
+ ll_sai_put(sai);
+ return rc;
+}
+
+static void sa_args_fini(struct md_enqueue_info *minfo,
+ struct ldlm_enqueue_info *einfo)
+{
+ LASSERT(minfo && einfo);
+ iput(minfo->mi_dir);
+ capa_put(minfo->mi_data.op_capa1);
+ capa_put(minfo->mi_data.op_capa2);
+ OBD_FREE_PTR(minfo);
+ OBD_FREE_PTR(einfo);
+}
+
+/**
+ * There is race condition between "capa_put" and "ll_statahead_interpret" for
+ * accessing "op_data.op_capa[1,2]" as following:
+ * "capa_put" releases "op_data.op_capa[1,2]"'s reference count after calling
+ * "md_intent_getattr_async". But "ll_statahead_interpret" maybe run first, and
+ * fill "op_data.op_capa[1,2]" as POISON, then cause "capa_put" access invalid
+ * "ocapa". So here reserve "op_data.op_capa[1,2]" in "pcapa" before calling
+ * "md_intent_getattr_async".
+ */
+static int sa_args_init(struct inode *dir, struct inode *child,
+ struct ll_sa_entry *entry, struct md_enqueue_info **pmi,
+ struct ldlm_enqueue_info **pei,
+ struct obd_capa **pcapa)
+{
+ struct qstr *qstr = &entry->se_qstr;
+ struct ll_inode_info *lli = ll_i2info(dir);
+ struct md_enqueue_info *minfo;
+ struct ldlm_enqueue_info *einfo;
+ struct md_op_data *op_data;
+
+ einfo = kzalloc(sizeof(*einfo), GFP_NOFS);
+ if (!einfo)
+ return -ENOMEM;
+
+ minfo = kzalloc(sizeof(*minfo), GFP_NOFS);
+ if (!minfo) {
+ OBD_FREE_PTR(einfo);
+ return -ENOMEM;
+ }
+
+ op_data = ll_prep_md_op_data(&minfo->mi_data, dir, child, qstr->name,
+ qstr->len, 0, LUSTRE_OPC_ANY, NULL);
+ if (IS_ERR(op_data)) {
+ OBD_FREE_PTR(einfo);
+ OBD_FREE_PTR(minfo);
+ return PTR_ERR(op_data);
+ }
+
+ minfo->mi_it.it_op = IT_GETATTR;
+ minfo->mi_dir = igrab(dir);
+ minfo->mi_cb = ll_statahead_interpret;
+ minfo->mi_generation = lli->lli_sai->sai_generation;
+ minfo->mi_cbdata = entry->se_index;
+
+ einfo->ei_type = LDLM_IBITS;
+ einfo->ei_mode = it_to_lock_mode(&minfo->mi_it);
+ einfo->ei_cb_bl = ll_md_blocking_ast;
+ einfo->ei_cb_cp = ldlm_completion_ast;
+ einfo->ei_cb_gl = NULL;
+ einfo->ei_cbdata = NULL;
+
+ *pmi = minfo;
+ *pei = einfo;
+ pcapa[0] = op_data->op_capa1;
+ pcapa[1] = op_data->op_capa2;
+
+ return 0;
+}
+
+static int do_sa_lookup(struct inode *dir, struct ll_sa_entry *entry)
+{
+ struct md_enqueue_info *minfo;
+ struct ldlm_enqueue_info *einfo;
+ struct obd_capa *capas[2];
+ int rc;
+
+ rc = sa_args_init(dir, NULL, entry, &minfo, &einfo, capas);
+ if (rc)
+ return rc;
+
+ rc = md_intent_getattr_async(ll_i2mdexp(dir), minfo, einfo);
+ if (!rc) {
+ capa_put(capas[0]);
+ capa_put(capas[1]);
+ } else {
+ sa_args_fini(minfo, einfo);
+ }
+
+ return rc;
+}
+
+/**
+ * similar to ll_revalidate_it().
+ * \retval 1 -- dentry valid
+ * \retval 0 -- will send stat-ahead request
+ * \retval others -- prepare stat-ahead request failed
+ */
+static int do_sa_revalidate(struct inode *dir, struct ll_sa_entry *entry,
+ struct dentry *dentry)
+{
+ struct inode *inode = d_inode(dentry);
+ struct lookup_intent it = { .it_op = IT_GETATTR,
+ .d.lustre.it_lock_handle = 0 };
+ struct md_enqueue_info *minfo;
+ struct ldlm_enqueue_info *einfo;
+ struct obd_capa *capas[2];
+ int rc;
+
+ if (unlikely(inode == NULL))
+ return 1;
+
+ if (d_mountpoint(dentry))
+ return 1;
+
+ entry->se_inode = igrab(inode);
+ rc = md_revalidate_lock(ll_i2mdexp(dir), &it, ll_inode2fid(inode),
+ NULL);
+ if (rc == 1) {
+ entry->se_handle = it.d.lustre.it_lock_handle;
+ ll_intent_release(&it);
+ return 1;
+ }
+
+ rc = sa_args_init(dir, inode, entry, &minfo, &einfo, capas);
+ if (rc) {
+ entry->se_inode = NULL;
+ iput(inode);
+ return rc;
+ }
+
+ rc = md_intent_getattr_async(ll_i2mdexp(dir), minfo, einfo);
+ if (!rc) {
+ capa_put(capas[0]);
+ capa_put(capas[1]);
+ } else {
+ entry->se_inode = NULL;
+ iput(inode);
+ sa_args_fini(minfo, einfo);
+ }
+
+ return rc;
+}
+
+static void ll_statahead_one(struct dentry *parent, const char *entry_name,
+ int entry_name_len)
+{
+ struct inode *dir = d_inode(parent);
+ struct ll_inode_info *lli = ll_i2info(dir);
+ struct ll_statahead_info *sai = lli->lli_sai;
+ struct dentry *dentry = NULL;
+ struct ll_sa_entry *entry;
+ int rc;
+ int rc1;
+
+ entry = ll_sa_entry_alloc(sai, sai->sai_index, entry_name,
+ entry_name_len);
+ if (IS_ERR(entry))
+ return;
+
+ dentry = d_lookup(parent, &entry->se_qstr);
+ if (!dentry) {
+ rc = do_sa_lookup(dir, entry);
+ } else {
+ rc = do_sa_revalidate(dir, entry, dentry);
+ if (rc == 1 && agl_should_run(sai, d_inode(dentry)))
+ ll_agl_add(sai, d_inode(dentry), entry->se_index);
+ }
+
+ if (dentry != NULL)
+ dput(dentry);
+
+ if (rc) {
+ rc1 = ll_sa_entry_to_stated(sai, entry,
+ rc < 0 ? SA_ENTRY_INVA : SA_ENTRY_SUCC);
+ if (rc1 == 0 && entry->se_index == sai->sai_index_wait)
+ wake_up(&sai->sai_waitq);
+ } else {
+ sai->sai_sent++;
+ }
+
+ sai->sai_index++;
+ /* drop one refcount on entry by ll_sa_entry_alloc */
+ ll_sa_entry_put(sai, entry);
+}
+
+static int ll_agl_thread(void *arg)
+{
+ struct dentry *parent = (struct dentry *)arg;
+ struct inode *dir = d_inode(parent);
+ struct ll_inode_info *plli = ll_i2info(dir);
+ struct ll_inode_info *clli;
+ struct ll_sb_info *sbi = ll_i2sbi(dir);
+ struct ll_statahead_info *sai = ll_sai_get(plli->lli_sai);
+ struct ptlrpc_thread *thread = &sai->sai_agl_thread;
+ struct l_wait_info lwi = { 0 };
+
+ thread->t_pid = current_pid();
+ CDEBUG(D_READA, "agl thread started: sai %p, parent %pd\n",
+ sai, parent);
+
+ atomic_inc(&sbi->ll_agl_total);
+ spin_lock(&plli->lli_agl_lock);
+ sai->sai_agl_valid = 1;
+ if (thread_is_init(thread))
+ /* If someone else has changed the thread state
+ * (e.g. already changed to SVC_STOPPING), we can't just
+ * blindly overwrite that setting. */
+ thread_set_flags(thread, SVC_RUNNING);
+ spin_unlock(&plli->lli_agl_lock);
+ wake_up(&thread->t_ctl_waitq);
+
+ while (1) {
+ l_wait_event(thread->t_ctl_waitq,
+ !agl_list_empty(sai) ||
+ !thread_is_running(thread),
+ &lwi);
+
+ if (!thread_is_running(thread))
+ break;
+
+ spin_lock(&plli->lli_agl_lock);
+ /* The statahead thread maybe help to process AGL entries,
+ * so check whether list empty again. */
+ if (!agl_list_empty(sai)) {
+ clli = agl_first_entry(sai);
+ list_del_init(&clli->lli_agl_list);
+ spin_unlock(&plli->lli_agl_lock);
+ ll_agl_trigger(&clli->lli_vfs_inode, sai);
+ } else {
+ spin_unlock(&plli->lli_agl_lock);
+ }
+ }
+
+ spin_lock(&plli->lli_agl_lock);
+ sai->sai_agl_valid = 0;
+ while (!agl_list_empty(sai)) {
+ clli = agl_first_entry(sai);
+ list_del_init(&clli->lli_agl_list);
+ spin_unlock(&plli->lli_agl_lock);
+ clli->lli_agl_index = 0;
+ iput(&clli->lli_vfs_inode);
+ spin_lock(&plli->lli_agl_lock);
+ }
+ thread_set_flags(thread, SVC_STOPPED);
+ spin_unlock(&plli->lli_agl_lock);
+ wake_up(&thread->t_ctl_waitq);
+ ll_sai_put(sai);
+ CDEBUG(D_READA, "agl thread stopped: sai %p, parent %pd\n",
+ sai, parent);
+ return 0;
+}
+
+static void ll_start_agl(struct dentry *parent, struct ll_statahead_info *sai)
+{
+ struct ptlrpc_thread *thread = &sai->sai_agl_thread;
+ struct l_wait_info lwi = { 0 };
+ struct ll_inode_info *plli;
+ struct task_struct *task;
+
+ CDEBUG(D_READA, "start agl thread: sai %p, parent %pd\n",
+ sai, parent);
+
+ plli = ll_i2info(d_inode(parent));
+ task = kthread_run(ll_agl_thread, parent,
+ "ll_agl_%u", plli->lli_opendir_pid);
+ if (IS_ERR(task)) {
+ CERROR("can't start ll_agl thread, rc: %ld\n", PTR_ERR(task));
+ thread_set_flags(thread, SVC_STOPPED);
+ return;
+ }
+
+ l_wait_event(thread->t_ctl_waitq,
+ thread_is_running(thread) || thread_is_stopped(thread),
+ &lwi);
+}
+
+static int ll_statahead_thread(void *arg)
+{
+ struct dentry *parent = (struct dentry *)arg;
+ struct inode *dir = d_inode(parent);
+ struct ll_inode_info *plli = ll_i2info(dir);
+ struct ll_inode_info *clli;
+ struct ll_sb_info *sbi = ll_i2sbi(dir);
+ struct ll_statahead_info *sai = ll_sai_get(plli->lli_sai);
+ struct ptlrpc_thread *thread = &sai->sai_thread;
+ struct ptlrpc_thread *agl_thread = &sai->sai_agl_thread;
+ struct page *page;
+ __u64 pos = 0;
+ int first = 0;
+ int rc = 0;
+ struct ll_dir_chain chain;
+ struct l_wait_info lwi = { 0 };
+
+ thread->t_pid = current_pid();
+ CDEBUG(D_READA, "statahead thread starting: sai %p, parent %pd\n",
+ sai, parent);
+
+ if (sbi->ll_flags & LL_SBI_AGL_ENABLED)
+ ll_start_agl(parent, sai);
+
+ atomic_inc(&sbi->ll_sa_total);
+ spin_lock(&plli->lli_sa_lock);
+ if (thread_is_init(thread))
+ /* If someone else has changed the thread state
+ * (e.g. already changed to SVC_STOPPING), we can't just
+ * blindly overwrite that setting. */
+ thread_set_flags(thread, SVC_RUNNING);
+ spin_unlock(&plli->lli_sa_lock);
+ wake_up(&thread->t_ctl_waitq);
+
+ ll_dir_chain_init(&chain);
+ page = ll_get_dir_page(dir, pos, &chain);
+
+ while (1) {
+ struct lu_dirpage *dp;
+ struct lu_dirent *ent;
+
+ if (IS_ERR(page)) {
+ rc = PTR_ERR(page);
+ CDEBUG(D_READA, "error reading dir "DFID" at %llu/%llu: [rc %d] [parent %u]\n",
+ PFID(ll_inode2fid(dir)), pos, sai->sai_index,
+ rc, plli->lli_opendir_pid);
+ goto out;
+ }
+
+ dp = page_address(page);
+ for (ent = lu_dirent_start(dp); ent != NULL;
+ ent = lu_dirent_next(ent)) {
+ __u64 hash;
+ int namelen;
+ char *name;
+
+ hash = le64_to_cpu(ent->lde_hash);
+ if (unlikely(hash < pos))
+ /*
+ * Skip until we find target hash value.
+ */
+ continue;
+
+ namelen = le16_to_cpu(ent->lde_namelen);
+ if (unlikely(namelen == 0))
+ /*
+ * Skip dummy record.
+ */
+ continue;
+
+ name = ent->lde_name;
+ if (name[0] == '.') {
+ if (namelen == 1) {
+ /*
+ * skip "."
+ */
+ continue;
+ } else if (name[1] == '.' && namelen == 2) {
+ /*
+ * skip ".."
+ */
+ continue;
+ } else if (!sai->sai_ls_all) {
+ /*
+ * skip hidden files.
+ */
+ sai->sai_skip_hidden++;
+ continue;
+ }
+ }
+
+ /*
+ * don't stat-ahead first entry.
+ */
+ if (unlikely(++first == 1))
+ continue;
+
+keep_it:
+ l_wait_event(thread->t_ctl_waitq,
+ !sa_sent_full(sai) ||
+ !sa_received_empty(sai) ||
+ !agl_list_empty(sai) ||
+ !thread_is_running(thread),
+ &lwi);
+
+interpret_it:
+ while (!sa_received_empty(sai))
+ ll_post_statahead(sai);
+
+ if (unlikely(!thread_is_running(thread))) {
+ ll_release_page(page, 0);
+ rc = 0;
+ goto out;
+ }
+
+ /* If no window for metadata statahead, but there are
+ * some AGL entries to be triggered, then try to help
+ * to process the AGL entries. */
+ if (sa_sent_full(sai)) {
+ spin_lock(&plli->lli_agl_lock);
+ while (!agl_list_empty(sai)) {
+ clli = agl_first_entry(sai);
+ list_del_init(&clli->lli_agl_list);
+ spin_unlock(&plli->lli_agl_lock);
+ ll_agl_trigger(&clli->lli_vfs_inode,
+ sai);
+
+ if (!sa_received_empty(sai))
+ goto interpret_it;
+
+ if (unlikely(
+ !thread_is_running(thread))) {
+ ll_release_page(page, 0);
+ rc = 0;
+ goto out;
+ }
+
+ if (!sa_sent_full(sai))
+ goto do_it;
+
+ spin_lock(&plli->lli_agl_lock);
+ }
+ spin_unlock(&plli->lli_agl_lock);
+
+ goto keep_it;
+ }
+
+do_it:
+ ll_statahead_one(parent, name, namelen);
+ }
+ pos = le64_to_cpu(dp->ldp_hash_end);
+ if (pos == MDS_DIR_END_OFF) {
+ /*
+ * End of directory reached.
+ */
+ ll_release_page(page, 0);
+ while (1) {
+ l_wait_event(thread->t_ctl_waitq,
+ !sa_received_empty(sai) ||
+ sai->sai_sent == sai->sai_replied||
+ !thread_is_running(thread),
+ &lwi);
+
+ while (!sa_received_empty(sai))
+ ll_post_statahead(sai);
+
+ if (unlikely(!thread_is_running(thread))) {
+ rc = 0;
+ goto out;
+ }
+
+ if (sai->sai_sent == sai->sai_replied &&
+ sa_received_empty(sai))
+ break;
+ }
+
+ spin_lock(&plli->lli_agl_lock);
+ while (!agl_list_empty(sai) &&
+ thread_is_running(thread)) {
+ clli = agl_first_entry(sai);
+ list_del_init(&clli->lli_agl_list);
+ spin_unlock(&plli->lli_agl_lock);
+ ll_agl_trigger(&clli->lli_vfs_inode, sai);
+ spin_lock(&plli->lli_agl_lock);
+ }
+ spin_unlock(&plli->lli_agl_lock);
+
+ rc = 0;
+ goto out;
+ } else if (1) {
+ /*
+ * chain is exhausted.
+ * Normal case: continue to the next page.
+ */
+ ll_release_page(page, le32_to_cpu(dp->ldp_flags) &
+ LDF_COLLIDE);
+ page = ll_get_dir_page(dir, pos, &chain);
+ } else {
+ LASSERT(le32_to_cpu(dp->ldp_flags) & LDF_COLLIDE);
+ ll_release_page(page, 1);
+ /*
+ * go into overflow page.
+ */
+ }
+ }
+
+out:
+ if (sai->sai_agl_valid) {
+ spin_lock(&plli->lli_agl_lock);
+ thread_set_flags(agl_thread, SVC_STOPPING);
+ spin_unlock(&plli->lli_agl_lock);
+ wake_up(&agl_thread->t_ctl_waitq);
+
+ CDEBUG(D_READA, "stop agl thread: sai %p pid %u\n",
+ sai, (unsigned int)agl_thread->t_pid);
+ l_wait_event(agl_thread->t_ctl_waitq,
+ thread_is_stopped(agl_thread),
+ &lwi);
+ } else {
+ /* Set agl_thread flags anyway. */
+ thread_set_flags(&sai->sai_agl_thread, SVC_STOPPED);
+ }
+ ll_dir_chain_fini(&chain);
+ spin_lock(&plli->lli_sa_lock);
+ if (!sa_received_empty(sai)) {
+ thread_set_flags(thread, SVC_STOPPING);
+ spin_unlock(&plli->lli_sa_lock);
+
+ /* To release the resources held by received entries. */
+ while (!sa_received_empty(sai))
+ ll_post_statahead(sai);
+
+ spin_lock(&plli->lli_sa_lock);
+ }
+ thread_set_flags(thread, SVC_STOPPED);
+ spin_unlock(&plli->lli_sa_lock);
+ wake_up(&sai->sai_waitq);
+ wake_up(&thread->t_ctl_waitq);
+ ll_sai_put(sai);
+ dput(parent);
+ CDEBUG(D_READA, "statahead thread stopped: sai %p, parent %pd\n",
+ sai, parent);
+ return rc;
+}
+
+/**
+ * called in ll_file_release().
+ */
+void ll_stop_statahead(struct inode *dir, void *key)
+{
+ struct ll_inode_info *lli = ll_i2info(dir);
+
+ if (unlikely(key == NULL))
+ return;
+
+ spin_lock(&lli->lli_sa_lock);
+ if (lli->lli_opendir_key != key || lli->lli_opendir_pid == 0) {
+ spin_unlock(&lli->lli_sa_lock);
+ return;
+ }
+
+ lli->lli_opendir_key = NULL;
+
+ if (lli->lli_sai) {
+ struct l_wait_info lwi = { 0 };
+ struct ptlrpc_thread *thread = &lli->lli_sai->sai_thread;
+
+ if (!thread_is_stopped(thread)) {
+ thread_set_flags(thread, SVC_STOPPING);
+ spin_unlock(&lli->lli_sa_lock);
+ wake_up(&thread->t_ctl_waitq);
+
+ CDEBUG(D_READA, "stop statahead thread: sai %p pid %u\n",
+ lli->lli_sai, (unsigned int)thread->t_pid);
+ l_wait_event(thread->t_ctl_waitq,
+ thread_is_stopped(thread),
+ &lwi);
+ } else {
+ spin_unlock(&lli->lli_sa_lock);
+ }
+
+ /*
+ * Put the ref which was held when first statahead_enter.
+ * It maybe not the last ref for some statahead requests
+ * maybe inflight.
+ */
+ ll_sai_put(lli->lli_sai);
+ } else {
+ lli->lli_opendir_pid = 0;
+ spin_unlock(&lli->lli_sa_lock);
+ }
+}
+
+enum {
+ /**
+ * not first dirent, or is "."
+ */
+ LS_NONE_FIRST_DE = 0,
+ /**
+ * the first non-hidden dirent
+ */
+ LS_FIRST_DE,
+ /**
+ * the first hidden dirent, that is "."
+ */
+ LS_FIRST_DOT_DE
+};
+
+static int is_first_dirent(struct inode *dir, struct dentry *dentry)
+{
+ struct ll_dir_chain chain;
+ struct qstr *target = &dentry->d_name;
+ struct page *page;
+ __u64 pos = 0;
+ int dot_de;
+ int rc = LS_NONE_FIRST_DE;
+
+ ll_dir_chain_init(&chain);
+ page = ll_get_dir_page(dir, pos, &chain);
+
+ while (1) {
+ struct lu_dirpage *dp;
+ struct lu_dirent *ent;
+
+ if (IS_ERR(page)) {
+ struct ll_inode_info *lli = ll_i2info(dir);
+
+ rc = PTR_ERR(page);
+ CERROR("error reading dir "DFID" at %llu: [rc %d] [parent %u]\n",
+ PFID(ll_inode2fid(dir)), pos,
+ rc, lli->lli_opendir_pid);
+ break;
+ }
+
+ dp = page_address(page);
+ for (ent = lu_dirent_start(dp); ent != NULL;
+ ent = lu_dirent_next(ent)) {
+ __u64 hash;
+ int namelen;
+ char *name;
+
+ hash = le64_to_cpu(ent->lde_hash);
+ /* The ll_get_dir_page() can return any page containing
+ * the given hash which may be not the start hash. */
+ if (unlikely(hash < pos))
+ continue;
+
+ namelen = le16_to_cpu(ent->lde_namelen);
+ if (unlikely(namelen == 0))
+ /*
+ * skip dummy record.
+ */
+ continue;
+
+ name = ent->lde_name;
+ if (name[0] == '.') {
+ if (namelen == 1)
+ /*
+ * skip "."
+ */
+ continue;
+ else if (name[1] == '.' && namelen == 2)
+ /*
+ * skip ".."
+ */
+ continue;
+ else
+ dot_de = 1;
+ } else {
+ dot_de = 0;
+ }
+
+ if (dot_de && target->name[0] != '.') {
+ CDEBUG(D_READA, "%.*s skip hidden file %.*s\n",
+ target->len, target->name,
+ namelen, name);
+ continue;
+ }
+
+ if (target->len != namelen ||
+ memcmp(target->name, name, namelen) != 0)
+ rc = LS_NONE_FIRST_DE;
+ else if (!dot_de)
+ rc = LS_FIRST_DE;
+ else
+ rc = LS_FIRST_DOT_DE;
+
+ ll_release_page(page, 0);
+ goto out;
+ }
+ pos = le64_to_cpu(dp->ldp_hash_end);
+ if (pos == MDS_DIR_END_OFF) {
+ /*
+ * End of directory reached.
+ */
+ ll_release_page(page, 0);
+ break;
+ } else if (1) {
+ /*
+ * chain is exhausted
+ * Normal case: continue to the next page.
+ */
+ ll_release_page(page, le32_to_cpu(dp->ldp_flags) &
+ LDF_COLLIDE);
+ page = ll_get_dir_page(dir, pos, &chain);
+ } else {
+ /*
+ * go into overflow page.
+ */
+ LASSERT(le32_to_cpu(dp->ldp_flags) & LDF_COLLIDE);
+ ll_release_page(page, 1);
+ }
+ }
+
+out:
+ ll_dir_chain_fini(&chain);
+ return rc;
+}
+
+static void
+ll_sai_unplug(struct ll_statahead_info *sai, struct ll_sa_entry *entry)
+{
+ struct ptlrpc_thread *thread = &sai->sai_thread;
+ struct ll_sb_info *sbi = ll_i2sbi(sai->sai_inode);
+ int hit;
+
+ if (entry != NULL && entry->se_stat == SA_ENTRY_SUCC)
+ hit = 1;
+ else
+ hit = 0;
+
+ ll_sa_entry_fini(sai, entry);
+ if (hit) {
+ sai->sai_hit++;
+ sai->sai_consecutive_miss = 0;
+ sai->sai_max = min(2 * sai->sai_max, sbi->ll_sa_max);
+ } else {
+ struct ll_inode_info *lli = ll_i2info(sai->sai_inode);
+
+ sai->sai_miss++;
+ sai->sai_consecutive_miss++;
+ if (sa_low_hit(sai) && thread_is_running(thread)) {
+ atomic_inc(&sbi->ll_sa_wrong);
+ CDEBUG(D_READA, "Statahead for dir " DFID " hit ratio too low: hit/miss %llu/%llu, sent/replied %llu/%llu, stopping statahead thread\n",
+ PFID(&lli->lli_fid), sai->sai_hit,
+ sai->sai_miss, sai->sai_sent,
+ sai->sai_replied);
+ spin_lock(&lli->lli_sa_lock);
+ if (!thread_is_stopped(thread))
+ thread_set_flags(thread, SVC_STOPPING);
+ spin_unlock(&lli->lli_sa_lock);
+ }
+ }
+
+ if (!thread_is_stopped(thread))
+ wake_up(&thread->t_ctl_waitq);
+}
+
+/**
+ * Start statahead thread if this is the first dir entry.
+ * Otherwise if a thread is started already, wait it until it is ahead of me.
+ * \retval 1 -- find entry with lock in cache, the caller needs to do
+ * nothing.
+ * \retval 0 -- find entry in cache, but without lock, the caller needs
+ * refresh from MDS.
+ * \retval others -- the caller need to process as non-statahead.
+ */
+int do_statahead_enter(struct inode *dir, struct dentry **dentryp,
+ int only_unplug)
+{
+ struct ll_inode_info *lli = ll_i2info(dir);
+ struct ll_statahead_info *sai = lli->lli_sai;
+ struct dentry *parent;
+ struct ll_sa_entry *entry;
+ struct ptlrpc_thread *thread;
+ struct l_wait_info lwi = { 0 };
+ int rc = 0;
+ struct ll_inode_info *plli;
+
+ LASSERT(lli->lli_opendir_pid == current_pid());
+
+ if (sai) {
+ thread = &sai->sai_thread;
+ if (unlikely(thread_is_stopped(thread) &&
+ list_empty(&sai->sai_entries_stated))) {
+ /* to release resource */
+ ll_stop_statahead(dir, lli->lli_opendir_key);
+ return -EAGAIN;
+ }
+
+ if ((*dentryp)->d_name.name[0] == '.') {
+ if (sai->sai_ls_all ||
+ sai->sai_miss_hidden >= sai->sai_skip_hidden) {
+ /*
+ * Hidden dentry is the first one, or statahead
+ * thread does not skip so many hidden dentries
+ * before "sai_ls_all" enabled as below.
+ */
+ } else {
+ if (!sai->sai_ls_all)
+ /*
+ * It maybe because hidden dentry is not
+ * the first one, "sai_ls_all" was not
+ * set, then "ls -al" missed. Enable
+ * "sai_ls_all" for such case.
+ */
+ sai->sai_ls_all = 1;
+
+ /*
+ * Such "getattr" has been skipped before
+ * "sai_ls_all" enabled as above.
+ */
+ sai->sai_miss_hidden++;
+ return -EAGAIN;
+ }
+ }
+
+ entry = ll_sa_entry_get_byname(sai, &(*dentryp)->d_name);
+ if (entry == NULL || only_unplug) {
+ ll_sai_unplug(sai, entry);
+ return entry ? 1 : -EAGAIN;
+ }
+
+ if (!ll_sa_entry_stated(entry)) {
+ sai->sai_index_wait = entry->se_index;
+ lwi = LWI_TIMEOUT_INTR(cfs_time_seconds(30), NULL,
+ LWI_ON_SIGNAL_NOOP, NULL);
+ rc = l_wait_event(sai->sai_waitq,
+ ll_sa_entry_stated(entry) ||
+ thread_is_stopped(thread),
+ &lwi);
+ if (rc < 0) {
+ ll_sai_unplug(sai, entry);
+ return -EAGAIN;
+ }
+ }
+
+ if (entry->se_stat == SA_ENTRY_SUCC &&
+ entry->se_inode != NULL) {
+ struct inode *inode = entry->se_inode;
+ struct lookup_intent it = { .it_op = IT_GETATTR,
+ .d.lustre.it_lock_handle =
+ entry->se_handle };
+ __u64 bits;
+
+ rc = md_revalidate_lock(ll_i2mdexp(dir), &it,
+ ll_inode2fid(inode), &bits);
+ if (rc == 1) {
+ if (d_inode(*dentryp) == NULL) {
+ struct dentry *alias;
+
+ alias = ll_splice_alias(inode,
+ *dentryp);
+ if (IS_ERR(alias)) {
+ ll_sai_unplug(sai, entry);
+ return PTR_ERR(alias);
+ }
+ *dentryp = alias;
+ } else if (d_inode(*dentryp) != inode) {
+ /* revalidate, but inode is recreated */
+ CDEBUG(D_READA,
+ "stale dentry %pd inode %lu/%u, statahead inode %lu/%u\n",
+ *dentryp,
+ d_inode(*dentryp)->i_ino,
+ d_inode(*dentryp)->i_generation,
+ inode->i_ino,
+ inode->i_generation);
+ ll_sai_unplug(sai, entry);
+ return -ESTALE;
+ } else {
+ iput(inode);
+ }
+ entry->se_inode = NULL;
+
+ if ((bits & MDS_INODELOCK_LOOKUP) &&
+ d_lustre_invalid(*dentryp))
+ d_lustre_revalidate(*dentryp);
+ ll_intent_release(&it);
+ }
+ }
+
+ ll_sai_unplug(sai, entry);
+ return rc;
+ }
+
+ /* I am the "lli_opendir_pid" owner, only me can set "lli_sai". */
+ rc = is_first_dirent(dir, *dentryp);
+ if (rc == LS_NONE_FIRST_DE) {
+ /* It is not "ls -{a}l" operation, no need statahead for it. */
+ rc = -EAGAIN;
+ goto out;
+ }
+
+ sai = ll_sai_alloc();
+ if (sai == NULL) {
+ rc = -ENOMEM;
+ goto out;
+ }
+
+ sai->sai_ls_all = (rc == LS_FIRST_DOT_DE);
+ sai->sai_inode = igrab(dir);
+ if (unlikely(sai->sai_inode == NULL)) {
+ CWARN("Do not start stat ahead on dying inode "DFID"\n",
+ PFID(&lli->lli_fid));
+ rc = -ESTALE;
+ goto out;
+ }
+
+ /* get parent reference count here, and put it in ll_statahead_thread */
+ parent = dget((*dentryp)->d_parent);
+ if (unlikely(sai->sai_inode != d_inode(parent))) {
+ struct ll_inode_info *nlli = ll_i2info(d_inode(parent));
+
+ CWARN("Race condition, someone changed %pd just now: old parent "DFID", new parent "DFID"\n",
+ *dentryp,
+ PFID(&lli->lli_fid), PFID(&nlli->lli_fid));
+ dput(parent);
+ iput(sai->sai_inode);
+ rc = -EAGAIN;
+ goto out;
+ }
+
+ CDEBUG(D_READA, "start statahead thread: sai %p, parent %pd\n",
+ sai, parent);
+
+ /* The sai buffer already has one reference taken at allocation time,
+ * but as soon as we expose the sai by attaching it to the lli that
+ * default reference can be dropped by another thread calling
+ * ll_stop_statahead. We need to take a local reference to protect
+ * the sai buffer while we intend to access it. */
+ ll_sai_get(sai);
+ lli->lli_sai = sai;
+
+ plli = ll_i2info(d_inode(parent));
+ rc = PTR_ERR(kthread_run(ll_statahead_thread, parent,
+ "ll_sa_%u", plli->lli_opendir_pid));
+ thread = &sai->sai_thread;
+ if (IS_ERR_VALUE(rc)) {
+ CERROR("can't start ll_sa thread, rc: %d\n", rc);
+ dput(parent);
+ lli->lli_opendir_key = NULL;
+ thread_set_flags(thread, SVC_STOPPED);
+ thread_set_flags(&sai->sai_agl_thread, SVC_STOPPED);
+ /* Drop both our own local reference and the default
+ * reference from allocation time. */
+ ll_sai_put(sai);
+ ll_sai_put(sai);
+ LASSERT(lli->lli_sai == NULL);
+ return -EAGAIN;
+ }
+
+ l_wait_event(thread->t_ctl_waitq,
+ thread_is_running(thread) || thread_is_stopped(thread),
+ &lwi);
+ ll_sai_put(sai);
+
+ /*
+ * We don't stat-ahead for the first dirent since we are already in
+ * lookup.
+ */
+ return -EAGAIN;
+
+out:
+ if (sai != NULL)
+ OBD_FREE_PTR(sai);
+ spin_lock(&lli->lli_sa_lock);
+ lli->lli_opendir_key = NULL;
+ lli->lli_opendir_pid = 0;
+ spin_unlock(&lli->lli_sa_lock);
+ return rc;
+}
Code Review / kvmfornfv.git / blobdiff