diff options
Diffstat (limited to 'drivers/staging/lustre/lustre/llite/statahead.c')
| -rw-r--r-- | drivers/staging/lustre/lustre/llite/statahead.c | 1722 |
1 files changed, 1722 insertions, 0 deletions
diff --git a/drivers/staging/lustre/lustre/llite/statahead.c b/drivers/staging/lustre/lustre/llite/statahead.c new file mode 100644 index 000000000000..7747f8f2079d --- /dev/null +++ b/drivers/staging/lustre/lustre/llite/statahead.c @@ -0,0 +1,1722 @@ +/* + * 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 <obd_support.h> +#include <lustre_lite.h> +#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 = 0; +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; + + entry_size = sizeof(struct ll_sa_entry) + (len & ~3) + 4; + OBD_ALLOC(entry, entry_size); + if (unlikely(entry == NULL)) + RETURN(ERR_PTR(-ENOMEM)); + + CDEBUG(D_READA, "alloc sa entry %.*s(%p) index "LPU64"\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 "LPU64"\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); + if (entry->se_inode) + 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; + ENTRY; + + OBD_ALLOC_PTR(sai); + 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); + ENTRY; + + 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_EXIT; + } + + 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:"LPU64"] [replied:"LPU64"]\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); + } + + EXIT; +} + +/* 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; + ENTRY; + + 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_EXIT; + } + + /* 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_EXIT; + } + + /* + * 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 obtaion 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 && + cfs_time_before(cfs_time_shift(-1), lli->lli_glimpse_time)) { + up_write(&lli->lli_glimpse_sem); + lli->lli_agl_index = 0; + iput(inode); + RETURN_EXIT; + } + + CDEBUG(D_READA, "Handling (init) async glimpse: inode = " + DFID", idx = "LPU64"\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 = "LPU64", rc = %d\n", + PFID(&lli->lli_fid), index, rc); + + iput(inode); + + EXIT; +} + +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; + ENTRY; + + spin_lock(&lli->lli_sa_lock); + if (unlikely(sa_received_empty(sai))) { + spin_unlock(&lli->lli_sa_lock); + RETURN_EXIT; + } + 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) + GOTO(out, rc = -EFAULT); + + child = entry->se_inode; + if (child == NULL) { + /* + * lookup. + */ + LASSERT(fid_is_zero(&minfo->mi_data.op_fid2)); + + /* XXX: No fid in reply, this is probaly cross-ref case. + * SA can't handle it yet. */ + if (body->valid & OBD_MD_MDS) + GOTO(out, rc = -EAGAIN); + } 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) + GOTO(out, rc = -EAGAIN); + + rc = ll_prep_inode(&child, req, dir->i_sb, it); + if (rc) + GOTO(out, rc); + + 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); + + EXIT; + +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; + int wakeup; + ENTRY; + + if (it_disposition(it, DISP_LOOKUP_NEG)) + rc = -ENOENT; + + 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); + GOTO(out, rc = -ESTALE); + } 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); + GOTO(out, rc = -EBADFD); + } + + entry = ll_sa_entry_get_byindex(sai, minfo->mi_cbdata); + if (entry == NULL) { + sai->sai_replied++; + spin_unlock(&lli->lli_sa_lock); + GOTO(out, rc = -EIDRM); + } + + 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 = it->d.lustre.it_lock_handle; + ll_intent_drop_lock(it); + 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); + } + + EXIT; + +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; + + OBD_ALLOC_PTR(einfo); + if (einfo == NULL) + return -ENOMEM; + + OBD_ALLOC_PTR(minfo); + if (minfo == NULL) { + 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; + ENTRY; + + 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 = dentry->d_inode; + 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; + ENTRY; + + if (unlikely(inode == NULL)) + RETURN(1); + + if (d_mountpoint(dentry)) + RETURN(1); + + if (unlikely(dentry == dentry->d_sb->s_root)) + 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 = parent->d_inode; + 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; + + entry = ll_sa_entry_alloc(sai, sai->sai_index, entry_name, + entry_name_len); + if (IS_ERR(entry)) + RETURN_EXIT; + + 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, dentry->d_inode)) + ll_agl_add(sai, dentry->d_inode, 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); + + EXIT; +} + +static int ll_agl_thread(void *arg) +{ + struct dentry *parent = (struct dentry *)arg; + struct inode *dir = parent->d_inode; + 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 }; + ENTRY; + + CDEBUG(D_READA, "agl thread started: [pid %d] [parent %.*s]\n", + current_pid(), parent->d_name.len, parent->d_name.name); + + atomic_inc(&sbi->ll_agl_total); + spin_lock(&plli->lli_agl_lock); + sai->sai_agl_valid = 1; + 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: [pid %d] [parent %.*s]\n", + current_pid(), parent->d_name.len, parent->d_name.name); + 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; + task_t *task; + ENTRY; + + CDEBUG(D_READA, "start agl thread: [pid %d] [parent %.*s]\n", + current_pid(), parent->d_name.len, parent->d_name.name); + + plli = ll_i2info(parent->d_inode); + 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_EXIT; + } + + l_wait_event(thread->t_ctl_waitq, + thread_is_running(thread) || thread_is_stopped(thread), + &lwi); + EXIT; +} + +static int ll_statahead_thread(void *arg) +{ + struct dentry *parent = (struct dentry *)arg; + struct inode *dir = parent->d_inode; + 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 }; + ENTRY; + + CDEBUG(D_READA, "statahead thread started: [pid %d] [parent %.*s]\n", + current_pid(), parent->d_name.len, parent->d_name.name); + + 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); + 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 "LPU64 + "/"LPU64": [rc %d] [parent %u]\n", + PFID(ll_inode2fid(dir)), pos, sai->sai_index, + rc, plli->lli_opendir_pid); + GOTO(out, rc); + } + + 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); + GOTO(out, rc = 0); + } + + /* 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); + GOTO(out, rc = 0); + } + + 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))) + GOTO(out, rc = 0); + + 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); + + GOTO(out, rc = 0); + } 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); + sai->sai_in_readpage = 1; + page = ll_get_dir_page(dir, pos, &chain); + sai->sai_in_readpage = 0; + } else { + LASSERT(le32_to_cpu(dp->ldp_flags) & LDF_COLLIDE); + ll_release_page(page, 1); + /* + * go into overflow page. + */ + } + } + EXIT; + +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: [pid %d]\n", + current_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: [pid %d] [parent %.*s]\n", + current_pid(), parent->d_name.len, parent->d_name.name); + 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: [pid %d]\n", + current_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; + ENTRY; + + 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 "LPU64": " + "[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, rc); + } + 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); + } + } + EXIT; + +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; + ENTRY; + + 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 "LPU64"/"LPU64 + ", sent/replied "LPU64"/"LPU64", stopping " + "statahead thread: pid %d\n", + PFID(&lli->lli_fid), sai->sai_hit, + sai->sai_miss, sai->sai_sent, + sai->sai_replied, current_pid()); + 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); + + EXIT; +} + +/** + * 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; + ENTRY; + + 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 statahead is busy in readdir, help it do post-work */ + while (!ll_sa_entry_stated(entry) && + sai->sai_in_readpage && + !sa_received_empty(sai)) + ll_post_statahead(sai); + + 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 ((*dentryp)->d_inode == NULL) { + *dentryp = ll_splice_alias(inode, + *dentryp); + } else if ((*dentryp)->d_inode != inode) { + /* revalidate, but inode is recreated */ + CDEBUG(D_READA, + "stale dentry %.*s inode %lu/%u, " + "statahead inode %lu/%u\n", + (*dentryp)->d_name.len, + (*dentryp)->d_name.name, + (*dentryp)->d_inode->i_ino, + (*dentryp)->d_inode->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. */ + GOTO(out, rc = -EAGAIN); + + sai = ll_sai_alloc(); + if (sai == NULL) + GOTO(out, rc = -ENOMEM); + + 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)); + GOTO(out, rc = -ESTALE); + } + + /* get parent reference count here, and put it in ll_statahead_thread */ + parent = dget((*dentryp)->d_parent); + if (unlikely(sai->sai_inode != parent->d_inode)) { + struct ll_inode_info *nlli = ll_i2info(parent->d_inode); + + CWARN("Race condition, someone changed %.*s just now: " + "old parent "DFID", new parent "DFID"\n", + (*dentryp)->d_name.len, (*dentryp)->d_name.name, + PFID(&lli->lli_fid), PFID(&nlli->lli_fid)); + dput(parent); + iput(sai->sai_inode); + GOTO(out, rc = -EAGAIN); + } + + CDEBUG(D_READA, "start statahead thread: [pid %d] [parent %.*s]\n", + current_pid(), parent->d_name.len, parent->d_name.name); + + lli->lli_sai = sai; + + plli = ll_i2info(parent->d_inode); + 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); + 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); + + /* + * 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; +} |