X-Git-Url: https://git.whamcloud.com/?p=fs%2Flustre-release.git;a=blobdiff_plain;f=lustre%2Fllite%2Fstatahead.c;h=0f1dfe3ad2e0e1e28f585ee952ed27bd7df32648;hp=cc290aad82d432f198740bd2ca1be48bf066940e;hb=38e6ee6fb779c34c7ef3eb4a010332385b3b84c1;hpb=8e13d34da223e0fc86a7cd269675b067e353f829 diff --git a/lustre/llite/statahead.c b/lustre/llite/statahead.c index cc290aa..0f1dfe3 100644 --- a/lustre/llite/statahead.c +++ b/lustre/llite/statahead.c @@ -15,11 +15,7 @@ * * 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. + * http://www.gnu.org/licenses/gpl-2.0.html * * GPL HEADER END */ @@ -27,7 +23,7 @@ * Copyright (c) 2008, 2010, Oracle and/or its affiliates. All rights reserved. * Use is subject to license terms. * - * Copyright (c) 2011, 2013, Intel Corporation. + * Copyright (c) 2011, 2017, Intel Corporation. */ /* * This file is part of Lustre, http://www.lustre.org/ @@ -36,6 +32,7 @@ #include #include +#include #include #include #include @@ -43,89 +40,85 @@ #define DEBUG_SUBSYSTEM S_LLITE #include -#include #include #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} */ + /** negative values are for error cases */ + SA_ENTRY_INIT = 0, /** init entry */ + SA_ENTRY_SUCC = 1, /** stat succeed */ + SA_ENTRY_INVA = 2, /** invalid entry */ +} se_state_t; + +/* sa_entry is not refcounted: statahead thread allocates it and do async stat, + * and in async stat callback ll_statahead_interpret() will add it into + * sai_interim_entries, later statahead thread will call sa_handle_callback() to + * instantiate entry and move it into sai_entries, and then only scanner process + * can access and free it. */ +struct sa_entry { + /* link into sai_interim_entries or sai_entries */ 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; + __u64 se_index; /* low layer ldlm lock handle */ - __u64 se_handle; + __u64 se_handle; /* entry status */ - se_stat_t se_stat; + se_state_t se_state; /* entry size, contains name */ - int se_size; + 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; + struct inode *se_inode; /* entry name */ - struct qstr se_qstr; + struct qstr se_qstr; + /* entry fid */ + struct lu_fid se_fid; }; static unsigned int sai_generation = 0; static DEFINE_SPINLOCK(sai_generation_lock); -static inline int ll_sa_entry_unhashed(struct ll_sa_entry *entry) +static inline int sa_unhashed(struct 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) +/* sa_entry is ready to use */ +static inline int sa_ready(struct sa_entry *entry) { - smp_rmb(); - return (entry->se_stat != SA_ENTRY_INIT); + smp_rmb(); + return (entry->se_state != SA_ENTRY_INIT); } -static inline int ll_sa_entry_hash(int val) +/* hash value to put in sai_cache */ +static inline int sa_hash(int val) { - return val & LL_SA_CACHE_MASK; + return val & LL_SA_CACHE_MASK; } -/* - * Insert entry to hash SA table. - */ +/* hash entry into sai_cache */ static inline void -ll_sa_entry_enhash(struct ll_statahead_info *sai, struct ll_sa_entry *entry) +sa_rehash(struct ll_statahead_info *sai, struct sa_entry *entry) { - int i = ll_sa_entry_hash(entry->se_qstr.hash); + int i = sa_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. - */ +/* unhash entry from sai_cache */ static inline void -ll_sa_entry_unhash(struct ll_statahead_info *sai, struct ll_sa_entry *entry) +sa_unhash(struct ll_statahead_info *sai, struct sa_entry *entry) { - int i = ll_sa_entry_hash(entry->se_qstr.hash); + int i = sa_hash(entry->se_qstr.hash); spin_lock(&sai->sai_cache_lock[i]); list_del_init(&entry->se_hash); @@ -138,33 +131,28 @@ static inline int agl_should_run(struct ll_statahead_info *sai, 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); + return list_entry(sai->sai_agls.next, struct ll_inode_info, + lli_agl_list); } +/* statahead window is full */ 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) +/* got async stat replies */ +static inline int sa_has_callback(struct ll_statahead_info *sai) { - return list_empty(&sai->sai_entries_received); + return !list_empty(&sai->sai_interim_entries); } static inline int agl_list_empty(struct ll_statahead_info *sai) { - return list_empty(&sai->sai_entries_agl); + return list_empty(&sai->sai_agls); } /** @@ -180,7 +168,7 @@ static inline int sa_low_hit(struct ll_statahead_info *sai) } /* - * If the given index is behind of statahead window more than + * 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) @@ -189,67 +177,42 @@ static inline int is_omitted_entry(struct ll_statahead_info *sai, __u64 index) 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) +/* allocate sa_entry and hash it to allow scanner process to find it */ +static struct sa_entry * +sa_alloc(struct dentry *parent, struct ll_statahead_info *sai, __u64 index, + const char *name, int len, const struct lu_fid *fid) { - 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", + struct ll_inode_info *lli; + struct sa_entry *entry; + int entry_size; + char *dname; + ENTRY; + + entry_size = sizeof(struct 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 %llu\n", len, name, entry, index); - entry->se_index = 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_state = SA_ENTRY_INIT; entry->se_size = entry_size; - dname = (char *)entry + sizeof(struct ll_sa_entry); + dname = (char *)entry + sizeof(struct sa_entry); memcpy(dname, name, len); dname[len] = 0; - entry->se_qstr.hash = full_name_hash(name, len); + entry->se_qstr.hash = ll_full_name_hash(parent, name, len); entry->se_qstr.len = len; entry->se_qstr.name = dname; + entry->se_fid = *fid; + + lli = ll_i2info(sai->sai_dentry->d_inode); - 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); + sa_rehash(sai, entry); spin_unlock(&lli->lli_sa_lock); atomic_inc(&sai->sai_cache_count); @@ -257,187 +220,210 @@ ll_sa_entry_alloc(struct ll_statahead_info *sai, __u64 index, 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) +/* free sa_entry, which should have been unhashed and not in any list */ +static void sa_free(struct ll_statahead_info *sai, struct sa_entry *entry) { - struct ll_sa_entry *entry; - int i = ll_sa_entry_hash(qstr->hash); + CDEBUG(D_READA, "free sa entry %.*s(%p) index %llu\n", + entry->se_qstr.len, entry->se_qstr.name, entry, + entry->se_index); - 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; + LASSERT(list_empty(&entry->se_list)); + LASSERT(sa_unhashed(entry)); + + OBD_FREE(entry, entry->se_size); + atomic_dec(&sai->sai_cache_count); } /* - * 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. + * find sa_entry by name, used by directory scanner, lock is not needed because + * only scanner can remove the entry from cache. */ -static struct ll_sa_entry * -ll_sa_entry_get_byindex(struct ll_statahead_info *sai, __u64 index) +static struct sa_entry * +sa_get(struct ll_statahead_info *sai, const struct qstr *qstr) { - struct ll_sa_entry *entry; + struct sa_entry *entry; + int i = sa_hash(qstr->hash); - 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); + 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; - } - if (entry->se_index > index) - break; } return NULL; } -static void ll_sa_entry_cleanup(struct ll_statahead_info *sai, - struct ll_sa_entry *entry) +/* unhash and unlink sa_entry, and then free it */ +static inline void +sa_kill(struct ll_statahead_info *sai, struct 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); - } + struct ll_inode_info *lli = ll_i2info(sai->sai_dentry->d_inode); - if (req) { - entry->se_req = NULL; - ptlrpc_req_finished(req); - } -} + LASSERT(!sa_unhashed(entry)); + LASSERT(!list_empty(&entry->se_list)); + LASSERT(sa_ready(entry)); -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); + sa_unhash(sai, entry); - LASSERT(list_empty(&entry->se_link)); - LASSERT(list_empty(&entry->se_list)); - LASSERT(ll_sa_entry_unhashed(entry)); + spin_lock(&lli->lli_sa_lock); + list_del_init(&entry->se_list); + spin_unlock(&lli->lli_sa_lock); - ll_sa_entry_cleanup(sai, entry); - if (entry->se_inode) - iput(entry->se_inode); + if (entry->se_inode != NULL) + iput(entry->se_inode); - OBD_FREE(entry, entry->se_size); - atomic_dec(&sai->sai_cache_count); - } + sa_free(sai, entry); } -static inline void -do_sa_entry_fini(struct ll_statahead_info *sai, struct ll_sa_entry *entry) +/* called by scanner after use, sa_entry will be killed */ +static void +sa_put(struct ll_statahead_info *sai, struct sa_entry *entry) { - struct ll_inode_info *lli = ll_i2info(sai->sai_inode); + struct sa_entry *tmp, *next; - LASSERT(!ll_sa_entry_unhashed(entry)); - LASSERT(!list_empty(&entry->se_link)); + if (entry != NULL && entry->se_state == SA_ENTRY_SUCC) { + struct ll_sb_info *sbi = ll_i2sbi(sai->sai_dentry->d_inode); - ll_sa_entry_unhash(sai, entry); + sai->sai_hit++; + sai->sai_consecutive_miss = 0; + sai->sai_max = min(2 * sai->sai_max, sbi->ll_sa_max); + } else { + sai->sai_miss++; + sai->sai_consecutive_miss++; + } - 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); + if (entry != NULL) + sa_kill(sai, entry); - ll_sa_entry_put(sai, entry); + /* kill old completed entries, only scanner process does this, no need + * to lock */ + list_for_each_entry_safe(tmp, next, &sai->sai_entries, se_list) { + if (!is_omitted_entry(sai, tmp->se_index)) + break; + sa_kill(sai, tmp); + } + + wake_up(&sai->sai_thread.t_ctl_waitq); } -/* - * 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) +/* update state and sort add entry to sai_entries by index, return true if + * scanner is waiting on this entry. */ +static bool +__sa_make_ready(struct ll_statahead_info *sai, struct sa_entry *entry, int ret) { - struct ll_sa_entry *pos, *next; + struct sa_entry *se; + struct list_head *pos = &sai->sai_entries; + __u64 index = entry->se_index; - if (entry) - do_sa_entry_fini(sai, entry); + LASSERT(!sa_ready(entry)); + LASSERT(list_empty(&entry->se_list)); - /* 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)) + list_for_each_entry_reverse(se, &sai->sai_entries, se_list) { + if (se->se_index < entry->se_index) { + pos = &se->se_list; break; - do_sa_entry_fini(sai, pos); + } } + list_add(&entry->se_list, pos); + /* + * LU-9210: ll_statahead_interpet must be able to see this before + * we wake it up + */ + smp_store_release(&entry->se_state, ret < 0 ? SA_ENTRY_INVA : SA_ENTRY_SUCC); + + return (index == sai->sai_index_wait); } +/* finish async stat RPC arguments */ +static void sa_fini_data(struct md_enqueue_info *minfo) +{ + ll_unlock_md_op_lsm(&minfo->mi_data); + iput(minfo->mi_dir); + OBD_FREE_PTR(minfo); +} + +static int ll_statahead_interpret(struct ptlrpc_request *req, + struct md_enqueue_info *minfo, int rc); + /* - * Inside lli_sa_lock. + * prepare arguments for async stat RPC. */ -static void -do_sa_entry_to_stated(struct ll_statahead_info *sai, - struct ll_sa_entry *entry, se_stat_t stat) +static struct md_enqueue_info * +sa_prep_data(struct inode *dir, struct inode *child, struct sa_entry *entry) { - struct ll_sa_entry *se; - struct list_head *pos = &sai->sai_entries_stated; + struct md_enqueue_info *minfo; + struct ldlm_enqueue_info *einfo; + struct md_op_data *op_data; + + OBD_ALLOC_PTR(minfo); + if (minfo == NULL) + return ERR_PTR(-ENOMEM); + + op_data = ll_prep_md_op_data(&minfo->mi_data, dir, child, + entry->se_qstr.name, entry->se_qstr.len, 0, + LUSTRE_OPC_ANY, NULL); + if (IS_ERR(op_data)) { + OBD_FREE_PTR(minfo); + return (struct md_enqueue_info *)op_data; + } - if (!list_empty(&entry->se_list)) - list_del_init(&entry->se_list); + if (child == NULL) + op_data->op_fid2 = entry->se_fid; - list_for_each_entry_reverse(se, &sai->sai_entries_stated, se_list) { - if (se->se_index < entry->se_index) { - pos = &se->se_list; - break; - } - } + minfo->mi_it.it_op = IT_GETATTR; + minfo->mi_dir = igrab(dir); + minfo->mi_cb = ll_statahead_interpret; + minfo->mi_cbdata = entry; - list_add(&entry->se_list, pos); - entry->se_stat = stat; + einfo = &minfo->mi_einfo; + 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; + + return minfo; } /* - * 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. + * release resources used in async stat RPC, update entry state and wakeup if + * scanner process it waiting on this entry. */ -static int -ll_sa_entry_to_stated(struct ll_statahead_info *sai, - struct ll_sa_entry *entry, se_stat_t stat) +static void +sa_make_ready(struct ll_statahead_info *sai, struct sa_entry *entry, int ret) { - struct ll_inode_info *lli = ll_i2info(sai->sai_inode); - int ret = 1; + struct ll_inode_info *lli = ll_i2info(sai->sai_dentry->d_inode); + struct md_enqueue_info *minfo = entry->se_minfo; + struct ptlrpc_request *req = entry->se_req; + bool wakeup; + + /* release resources used in RPC */ + if (minfo) { + entry->se_minfo = NULL; + ll_intent_release(&minfo->mi_it); + sa_fini_data(minfo); + } - ll_sa_entry_cleanup(sai, entry); + if (req) { + entry->se_req = NULL; + ptlrpc_req_finished(req); + } spin_lock(&lli->lli_sa_lock); - if (likely(entry->se_stat != SA_ENTRY_DEST)) { - do_sa_entry_to_stated(sai, entry, stat); - ret = 0; - } + wakeup = __sa_make_ready(sai, entry, ret); spin_unlock(&lli->lli_sa_lock); - return ret; + if (wakeup) + wake_up(&sai->sai_waitq); } -/* - * Insert inode into the list of sai_entries_agl. - */ +/* insert inode into the list of sai_agls */ 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); + struct ll_inode_info *parent = ll_i2info(sai->sai_dentry->d_inode); int added = 0; spin_lock(&child->lli_agl_lock); @@ -451,7 +437,7 @@ static void ll_agl_add(struct ll_statahead_info *sai, spin_lock(&parent->lli_agl_lock); if (agl_list_empty(sai)) added = 1; - list_add_tail(&child->lli_agl_list, &sai->sai_entries_agl); + list_add_tail(&child->lli_agl_list, &sai->sai_agls); spin_unlock(&parent->lli_agl_lock); } else { spin_unlock(&child->lli_agl_lock); @@ -461,34 +447,29 @@ static void ll_agl_add(struct ll_statahead_info *sai, wake_up(&sai->sai_agl_thread.t_ctl_waitq); } -static struct ll_statahead_info *ll_sai_alloc(void) +/* allocate sai */ +static struct ll_statahead_info *ll_sai_alloc(struct dentry *dentry) { struct ll_statahead_info *sai; - int i; + struct ll_inode_info *lli = ll_i2info(dentry->d_inode); + int i; ENTRY; OBD_ALLOC_PTR(sai); if (!sai) RETURN(NULL); + sai->sai_dentry = dget(dentry); 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_interim_entries); 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); + INIT_LIST_HEAD(&sai->sai_agls); for (i = 0; i < LL_SA_CACHE_SIZE; i++) { INIT_LIST_HEAD(&sai->sai_cache[i]); @@ -496,72 +477,82 @@ static struct ll_statahead_info *ll_sai_alloc(void) } atomic_set(&sai->sai_cache_count, 0); + spin_lock(&sai_generation_lock); + lli->lli_sa_generation = ++sai_generation; + if (unlikely(sai_generation == 0)) + lli->lli_sa_generation = ++sai_generation; + spin_unlock(&sai_generation_lock); + RETURN(sai); } -static inline struct ll_statahead_info * -ll_sai_get(struct ll_statahead_info *sai) +/* free sai */ +static inline void ll_sai_free(struct ll_statahead_info *sai) { - atomic_inc(&sai->sai_refcount); + LASSERT(sai->sai_dentry != NULL); + dput(sai->sai_dentry); + OBD_FREE_PTR(sai); +} + +/* + * take refcount of sai if sai for @dir exists, which means statahead is on for + * this directory. + */ +static inline struct ll_statahead_info *ll_sai_get(struct inode *dir) +{ + struct ll_inode_info *lli = ll_i2info(dir); + struct ll_statahead_info *sai = NULL; + + spin_lock(&lli->lli_sa_lock); + sai = lli->lli_sai; + if (sai != NULL) + atomic_inc(&sai->sai_refcount); + spin_unlock(&lli->lli_sa_lock); + return sai; } +/* + * put sai refcount after use, if refcount reaches zero, free sai and sa_entries + * attached to it. + */ 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; + struct ll_inode_info *lli = ll_i2info(sai->sai_dentry->d_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_EXIT; - } - - LASSERT(lli->lli_opendir_key == NULL); - LASSERT(thread_is_stopped(&sai->sai_thread)); - LASSERT(thread_is_stopped(&sai->sai_agl_thread)); + struct sa_entry *entry, *next; + struct ll_sb_info *sbi = ll_i2sbi(sai->sai_dentry->d_inode); 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(thread_is_stopped(&sai->sai_thread)); + LASSERT(thread_is_stopped(&sai->sai_agl_thread)); + LASSERT(sai->sai_sent == sai->sai_replied); + LASSERT(!sa_has_callback(sai)); - LASSERT(list_empty(&sai->sai_entries)); - LASSERT(sa_received_empty(sai)); - LASSERT(list_empty(&sai->sai_entries_stated)); + list_for_each_entry_safe(entry, next, &sai->sai_entries, + se_list) + sa_kill(sai, entry); LASSERT(atomic_read(&sai->sai_cache_count) == 0); LASSERT(agl_list_empty(sai)); - iput(inode); - OBD_FREE_PTR(sai); + ll_sai_free(sai); + atomic_dec(&sbi->ll_sa_running); } - - EXIT; } -/* Do NOT forget to drop inode refcount when into sai_entries_agl. */ +/* Do NOT forget to drop inode refcount when into sai_agls. */ 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; + struct ll_inode_info *lli = ll_i2info(inode); + u64 index = lli->lli_agl_index; + ktime_t expire; + int rc; + ENTRY; LASSERT(list_empty(&lli->lli_agl_list)); /* AGL maybe fall behind statahead with one entry */ @@ -571,6 +562,18 @@ static void ll_agl_trigger(struct inode *inode, struct ll_statahead_info *sai) RETURN_EXIT; } + /* In case of restore, the MDT has the right size and has already + * sent it back without granting the layout lock, inode is up-to-date. + * Then AGL (async glimpse lock) is useless. + * Also to glimpse we need the layout, in case of a runninh restore + * the MDT holds the layout lock so the glimpse will block up to the + * end of restore (statahead/agl will block) */ + if (ll_file_test_flag(lli, LLIF_FILE_RESTORING)) { + 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) { @@ -592,8 +595,9 @@ static void ll_agl_trigger(struct inode *inode, struct ll_statahead_info *sai) * 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)) { + expire = ktime_sub_ns(ktime_get(), NSEC_PER_SEC); + if (ktime_to_ns(lli->lli_glimpse_time) && + ktime_before(expire, lli->lli_glimpse_time)) { up_write(&lli->lli_glimpse_sem); lli->lli_agl_index = 0; iput(inode); @@ -601,15 +605,15 @@ static void ll_agl_trigger(struct inode *inode, struct ll_statahead_info *sai) } CDEBUG(D_READA, "Handling (init) async glimpse: inode = " - DFID", idx = "LPU64"\n", PFID(&lli->lli_fid), index); + DFID", idx = %llu\n", PFID(&lli->lli_fid), index); cl_agl(inode); lli->lli_agl_index = 0; - lli->lli_glimpse_time = cfs_time_current(); + lli->lli_glimpse_time = ktime_get(); up_write(&lli->lli_glimpse_sem); CDEBUG(D_READA, "Handled (init) async glimpse: inode= " - DFID", idx = "LPU64", rc = %d\n", + DFID", idx = %llu, rc = %d\n", PFID(&lli->lli_fid), index, rc); iput(inode); @@ -617,369 +621,277 @@ static void ll_agl_trigger(struct inode *inode, struct ll_statahead_info *sai) EXIT; } -static void ll_post_statahead(struct ll_statahead_info *sai) +/* + * prepare inode for sa entry, add it into agl list, now sa_entry is ready + * to be used by scanner process. + */ +static void sa_instantiate(struct ll_statahead_info *sai, + struct sa_entry *entry) { - 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; + struct inode *dir = sai->sai_dentry->d_inode; + struct inode *child; + 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); - 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->mbo_valid & OBD_MD_MDS) - GOTO(out, rc = -EAGAIN); - } else { - /* - * revalidate. - */ - /* unlinked and re-created with the same name */ + 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) { + /* revalidate; unlinked and re-created with the same name */ if (unlikely(!lu_fid_eq(&minfo->mi_data.op_fid2, &body->mbo_fid1))) { - entry->se_inode = NULL; - iput(child); - child = NULL; - } - } + entry->se_inode = NULL; + iput(child); + child = NULL; + } + } - it->d.lustre.it_lock_handle = entry->se_handle; + it->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); + if (rc != 1) + GOTO(out, rc = -EAGAIN); - rc = ll_prep_inode(&child, req, dir->i_sb, it); - if (rc) - GOTO(out, rc); + rc = ll_prep_inode(&child, req, dir->i_sb, it); + if (rc) + GOTO(out, rc); - CDEBUG(D_DLMTRACE, "%s: setting l_data to inode "DFID"(%p)\n", - ll_get_fsname(child->i_sb, NULL, 0), - PFID(ll_inode2fid(child)), child); - ll_set_lock_data(ll_i2sbi(dir)->ll_md_exp, child, it, NULL); + CDEBUG(D_READA, "%s: setting %.*s"DFID" l_data to inode %p\n", + ll_i2sbi(dir)->ll_fsname, entry->se_qstr.len, + entry->se_qstr.name, PFID(ll_inode2fid(child)), child); + ll_set_lock_data(ll_i2sbi(dir)->ll_md_exp, child, it, NULL); - entry->se_inode = child; + entry->se_inode = child; - if (agl_should_run(sai, child)) - ll_agl_add(sai, child, entry->se_index); + if (agl_should_run(sai, child)) + ll_agl_add(sai, child, entry->se_index); - EXIT; + 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); + /* sa_make_ready() will drop ldlm ibits lock refcount by calling + * ll_intent_drop_lock() in spite of failures. Do not worry about + * calling ll_intent_drop_lock() more than once. */ + sa_make_ready(sai, entry, rc); } -static int ll_statahead_interpret(struct ptlrpc_request *req, - struct md_enqueue_info *minfo, int rc) +/* once there are async stat replies, instantiate sa_entry from replies */ +static void sa_handle_callback(struct ll_statahead_info *sai) { - 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; + struct ll_inode_info *lli; - if (it_disposition(it, DISP_LOOKUP_NEG)) - rc = -ENOENT; + lli = ll_i2info(sai->sai_dentry->d_inode); spin_lock(&lli->lli_sa_lock); - /* stale entry */ - if (unlikely(lli->lli_sai == NULL || - lli->lli_sai->sai_generation != minfo->mi_generation)) { + while (sa_has_callback(sai)) { + struct sa_entry *entry; + + entry = list_entry(sai->sai_interim_entries.next, + struct sa_entry, se_list); + list_del_init(&entry->se_list); 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); - } + sa_instantiate(sai, entry); + spin_lock(&lli->lli_sa_lock); + } + spin_unlock(&lli->lli_sa_lock); +} - 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); +/* + * callback for async stat RPC, because this is called in ptlrpcd context, we + * only put sa_entry in sai_interim_entries, and wake up statahead thread to + * really prepare inode and instantiate sa_entry later. + */ +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 = lli->lli_sai; + struct sa_entry *entry = (struct sa_entry *)minfo->mi_cbdata; + __u64 handle = 0; + wait_queue_head_t *waitq = NULL; + ENTRY; - ll_sa_entry_put(sai, entry); - if (wakeup) - wake_up(&sai->sai_thread.t_ctl_waitq); - } + if (it_disposition(it, DISP_LOOKUP_NEG)) + rc = -ENOENT; - EXIT; + /* because statahead thread will wait for all inflight RPC to finish, + * sai should be always valid, no need to refcount */ + LASSERT(sai != NULL); + LASSERT(!thread_is_stopped(&sai->sai_thread)); + LASSERT(entry != NULL); -out: - if (rc != 0) { - ll_intent_release(it); - iput(dir); - OBD_FREE_PTR(minfo); - } - if (sai != NULL) - ll_sai_put(sai); - return rc; -} + CDEBUG(D_READA, "sa_entry %.*s rc %d\n", + entry->se_qstr.len, entry->se_qstr.name, 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); -} + if (rc != 0) { + ll_intent_release(it); + sa_fini_data(minfo); + } else { + /* 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->it_lock_handle; + ll_intent_drop_lock(it); + ll_unlock_md_op_lsm(&minfo->mi_data); + } -/** - * 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; - } + spin_lock(&lli->lli_sa_lock); + if (rc != 0) { + if (__sa_make_ready(sai, entry, rc)) + waitq = &sai->sai_waitq; + } 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; + if (!sa_has_callback(sai)) + waitq = &sai->sai_thread.t_ctl_waitq; + + list_add_tail(&entry->se_list, &sai->sai_interim_entries); + } + sai->sai_replied++; - 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); - } + if (waitq != NULL) + wake_up(waitq); + spin_unlock(&lli->lli_sa_lock); - 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; + RETURN(rc); } -static int do_sa_lookup(struct inode *dir, struct ll_sa_entry *entry) +/* async stat for file not found in dcache */ +static int sa_lookup(struct inode *dir, struct 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); - } + struct md_enqueue_info *minfo; + int rc; + ENTRY; + + minfo = sa_prep_data(dir, NULL, entry); + if (IS_ERR(minfo)) + RETURN(PTR_ERR(minfo)); + + rc = md_intent_getattr_async(ll_i2mdexp(dir), minfo); + if (rc < 0) + sa_fini_data(minfo); - RETURN(rc); + 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 + * async stat for file found in dcache, similar to .revalidate + * + * \retval 1 dentry valid, no RPC sent + * \retval 0 dentry invalid, will send async stat RPC + * \retval negative number upon error */ -static int do_sa_revalidate(struct inode *dir, struct ll_sa_entry *entry, - struct dentry *dentry) +static int sa_revalidate(struct inode *dir, struct 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); - - 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); - } + struct inode *inode = dentry->d_inode; + struct lookup_intent it = { .it_op = IT_GETATTR, + .it_lock_handle = 0 }; + struct md_enqueue_info *minfo; + int rc; + ENTRY; - rc = sa_args_init(dir, inode, entry, &minfo, &einfo, capas); - if (rc) { - entry->se_inode = NULL; - iput(inode); - RETURN(rc); - } + if (unlikely(inode == NULL)) + RETURN(1); - 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); - } + if (d_mountpoint(dentry)) + RETURN(1); + + minfo = sa_prep_data(dir, inode, entry); + if (IS_ERR(minfo)) + RETURN(PTR_ERR(minfo)); + + entry->se_inode = igrab(inode); + rc = md_revalidate_lock(ll_i2mdexp(dir), &it, ll_inode2fid(inode), + NULL); + if (rc == 1) { + entry->se_handle = it.it_lock_handle; + ll_intent_release(&it); + sa_fini_data(minfo); + RETURN(1); + } + + rc = md_intent_getattr_async(ll_i2mdexp(dir), minfo); + if (rc < 0) { + entry->se_inode = NULL; + iput(inode); + sa_fini_data(minfo); + } - RETURN(rc); + RETURN(rc); } -static void ll_statahead_one(struct dentry *parent, const char* entry_name, - int entry_name_len) +/* async stat for file with @name */ +static void sa_statahead(struct dentry *parent, const char *name, int len, + const struct lu_fid *fid) { - 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); - } + 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 sa_entry *entry; + int rc; + ENTRY; - if (dentry != NULL) - dput(dentry); + entry = sa_alloc(parent, sai, sai->sai_index, name, len, fid); + if (IS_ERR(entry)) + RETURN_EXIT; - 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); + dentry = d_lookup(parent, &entry->se_qstr); + if (!dentry) { + rc = sa_lookup(dir, entry); } else { - sai->sai_sent++; + rc = 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); } - sai->sai_index++; - /* drop one refcount on entry by ll_sa_entry_alloc */ - ll_sa_entry_put(sai, entry); + if (dentry != NULL) + dput(dentry); - EXIT; + if (rc != 0) + sa_make_ready(sai, entry, rc); + else + sai->sai_sent++; + + sai->sai_index++; + + EXIT; } +/* async glimpse (agl) thread main function */ 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; + 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; + struct ptlrpc_thread *thread; + ENTRY; + sai = ll_sai_get(dir); + thread = &sai->sai_agl_thread; thread->t_pid = current_pid(); CDEBUG(D_READA, "agl thread started: sai %p, parent %.*s\n", sai, parent->d_name.len, parent->d_name.name); @@ -995,14 +907,12 @@ static int ll_agl_thread(void *arg) 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; + while (1) { + wait_event_idle(thread->t_ctl_waitq, + !agl_list_empty(sai) || + !thread_is_running(thread)); + if (!thread_is_running(thread)) + break; spin_lock(&plli->lli_agl_lock); /* The statahead thread maybe help to process AGL entries, @@ -1012,6 +922,7 @@ static int ll_agl_thread(void *arg) list_del_init(&clli->lli_agl_list); spin_unlock(&plli->lli_agl_lock); ll_agl_trigger(&clli->lli_vfs_inode, sai); + cond_resched(); } else { spin_unlock(&plli->lli_agl_lock); } @@ -1036,10 +947,10 @@ static int ll_agl_thread(void *arg) RETURN(0); } +/* start agl thread */ 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; ENTRY; @@ -1056,76 +967,87 @@ static void ll_start_agl(struct dentry *parent, struct ll_statahead_info *sai) RETURN_EXIT; } - l_wait_event(thread->t_ctl_waitq, - thread_is_running(thread) || thread_is_stopped(thread), - &lwi); + wait_event_idle(thread->t_ctl_waitq, + thread_is_running(thread) || thread_is_stopped(thread)); EXIT; } +/* statahead thread main function */ 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; - int first = 0; - int rc = 0; - struct md_op_data *op_data; - struct ll_dir_chain chain; - struct l_wait_info lwi = { 0 }; - struct page *page = NULL; - __u64 pos = 0; + struct dentry *parent = (struct dentry *)arg; + struct inode *dir = parent->d_inode; + struct ll_inode_info *lli = ll_i2info(dir); + struct ll_sb_info *sbi = ll_i2sbi(dir); + struct ll_statahead_info *sai; + struct ptlrpc_thread *sa_thread; + struct ptlrpc_thread *agl_thread; + int first = 0; + struct md_op_data *op_data; + struct ll_dir_chain chain; + struct page *page = NULL; + __u64 pos = 0; + int rc = 0; ENTRY; - thread->t_pid = current_pid(); + sai = ll_sai_get(dir); + sa_thread = &sai->sai_thread; + agl_thread = &sai->sai_agl_thread; + sa_thread->t_pid = current_pid(); CDEBUG(D_READA, "statahead thread starting: sai %p, parent %.*s\n", sai, parent->d_name.len, parent->d_name.name); - op_data = ll_prep_md_op_data(NULL, dir, dir, NULL, 0, 0, - LUSTRE_OPC_ANY, dir); - if (IS_ERR(op_data)) - GOTO(out_put, rc = PTR_ERR(op_data)); - - op_data->op_max_pages = ll_i2sbi(dir)->ll_md_brw_pages; + OBD_ALLOC_PTR(op_data); + if (!op_data) + GOTO(out, rc = -ENOMEM); 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)) + spin_lock(&lli->lli_sa_lock); + if (thread_is_init(sa_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); + thread_set_flags(sa_thread, SVC_RUNNING); + spin_unlock(&lli->lli_sa_lock); + wake_up(&sa_thread->t_ctl_waitq); ll_dir_chain_init(&chain); - page = ll_get_dir_page(dir, op_data, pos, &chain); - while (1) { + while (pos != MDS_DIR_END_OFF && thread_is_running(sa_thread)) { struct lu_dirpage *dp; struct lu_dirent *ent; + op_data = ll_prep_md_op_data(op_data, dir, dir, NULL, 0, 0, + LUSTRE_OPC_ANY, dir); + if (IS_ERR(op_data)) { + rc = PTR_ERR(op_data); + break; + } + + sai->sai_in_readpage = 1; + page = ll_get_dir_page(dir, op_data, pos, &chain); + ll_unlock_md_op_lsm(op_data); + sai->sai_in_readpage = 0; if (IS_ERR(page)) { rc = PTR_ERR(page); - CDEBUG(D_READA, "error reading dir "DFID" at "LPU64 - "/"LPU64" opendir_pid = %u: rc = %d\n", + CDEBUG(D_READA, "error reading dir "DFID" at %llu" + "/%llu opendir_pid = %u: rc = %d\n", PFID(ll_inode2fid(dir)), pos, sai->sai_index, - plli->lli_opendir_pid, rc); - GOTO(out, rc); + lli->lli_opendir_pid, rc); + break; } dp = page_address(page); - for (ent = lu_dirent_start(dp); ent != NULL; + for (ent = lu_dirent_start(dp); + ent != NULL && thread_is_running(sa_thread) && + !sa_low_hit(sai); ent = lu_dirent_next(ent)) { __u64 hash; int namelen; char *name; + struct lu_fid fid; hash = le64_to_cpu(ent->lde_hash); if (unlikely(hash < pos)) @@ -1168,211 +1090,189 @@ static int ll_statahead_thread(void *arg) 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(dir, page, false); - GOTO(out, rc = 0); - } + fid_le_to_cpu(&fid, &ent->lde_fid); - /* 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); + /* wait for spare statahead window */ + do { + wait_event_idle(sa_thread->t_ctl_waitq, + !sa_sent_full(sai) || + sa_has_callback(sai) || + !agl_list_empty(sai) || + !thread_is_running(sa_thread)); - if (!sa_received_empty(sai)) - goto interpret_it; + sa_handle_callback(sai); - if (unlikely( - !thread_is_running(thread))) { - ll_release_page(dir, page, - false); - GOTO(out, rc = 0); - } + spin_lock(&lli->lli_agl_lock); + while (sa_sent_full(sai) && + !agl_list_empty(sai)) { + struct ll_inode_info *clli; - if (!sa_sent_full(sai)) - goto do_it; + clli = agl_first_entry(sai); + list_del_init(&clli->lli_agl_list); + spin_unlock(&lli->lli_agl_lock); - spin_lock(&plli->lli_agl_lock); + ll_agl_trigger(&clli->lli_vfs_inode, + sai); + cond_resched(); + spin_lock(&lli->lli_agl_lock); } - spin_unlock(&plli->lli_agl_lock); + spin_unlock(&lli->lli_agl_lock); + } while (sa_sent_full(sai) && + thread_is_running(sa_thread)); - goto keep_it; - } -do_it: - ll_statahead_one(parent, name, namelen); + sa_statahead(parent, name, namelen, &fid); } pos = le64_to_cpu(dp->ldp_hash_end); - if (pos == MDS_DIR_END_OFF) { - /* - * End of directory reached. - */ - ll_release_page(dir, page, false); - 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); + ll_release_page(dir, page, + le32_to_cpu(dp->ldp_flags) & LDF_COLLIDE); - GOTO(out, rc = 0); - } else { - /* - * chain is exhausted. - * Normal case: continue to the next page. - */ - ll_release_page(dir, page, le32_to_cpu(dp->ldp_flags) & - LDF_COLLIDE); - sai->sai_in_readpage = 1; - page = ll_get_dir_page(dir, op_data, pos, &chain); - sai->sai_in_readpage = 0; + if (sa_low_hit(sai)) { + rc = -EFAULT; + 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: pid %d\n", + PFID(&lli->lli_fid), sai->sai_hit, + sai->sai_miss, sai->sai_sent, + sai->sai_replied, current_pid()); + break; } } -out: - EXIT; ll_dir_chain_fini(&chain); ll_finish_md_op_data(op_data); -out_put: - if (sai->sai_agl_valid) { - spin_lock(&plli->lli_agl_lock); + + if (rc < 0) { + spin_lock(&lli->lli_sa_lock); + thread_set_flags(sa_thread, SVC_STOPPING); + lli->lli_sa_enabled = 0; + spin_unlock(&lli->lli_sa_lock); + } + + /* statahead is finished, but statahead entries need to be cached, wait + * for file release to stop me. */ + while (thread_is_running(sa_thread)) { + wait_event_idle(sa_thread->t_ctl_waitq, + sa_has_callback(sai) || + !thread_is_running(sa_thread)); + + sa_handle_callback(sai); + } + + EXIT; +out: + if (sai->sai_agl_valid) { + spin_lock(&lli->lli_agl_lock); thread_set_flags(agl_thread, SVC_STOPPING); - spin_unlock(&plli->lli_agl_lock); + spin_unlock(&lli->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); - } - 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); + wait_event_idle(agl_thread->t_ctl_waitq, + thread_is_stopped(agl_thread)); + } else { + /* Set agl_thread flags anyway. */ + thread_set_flags(agl_thread, SVC_STOPPED); + } - spin_lock(&plli->lli_sa_lock); + /* wait for inflight statahead RPCs to finish, and then we can free sai + * safely because statahead RPC will access sai data */ + while (sai->sai_sent != sai->sai_replied) { + /* in case we're not woken up, timeout wait */ + wait_event_idle_timeout(sa_thread->t_ctl_waitq, + sai->sai_sent == sai->sai_replied, + cfs_time_seconds(1) >> 3); } - 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); + + /* release resources held by statahead RPCs */ + sa_handle_callback(sai); + + spin_lock(&lli->lli_sa_lock); + thread_set_flags(sa_thread, SVC_STOPPED); + spin_unlock(&lli->lli_sa_lock); + CDEBUG(D_READA, "statahead thread stopped: sai %p, parent %.*s\n", sai, parent->d_name.len, parent->d_name.name); - dput(parent); + + wake_up(&sai->sai_waitq); + wake_up(&sa_thread->t_ctl_waitq); + ll_sai_put(sai); + return rc; } -/** - * called in ll_file_release(). - */ -void ll_stop_statahead(struct inode *dir, void *key) +/* authorize opened dir handle @key to statahead */ +void ll_authorize_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_opendir_key == NULL && lli->lli_sai == NULL) { + /* + * if lli_sai is not NULL, it means previous statahead is not + * finished yet, we'd better not start a new statahead for now. + */ + LASSERT(lli->lli_opendir_pid == 0); + lli->lli_opendir_key = key; + lli->lli_opendir_pid = current_pid(); + lli->lli_sa_enabled = 1; + } + spin_unlock(&lli->lli_sa_lock); +} - if (lli->lli_sai) { - struct l_wait_info lwi = { 0 }; - struct ptlrpc_thread *thread = &lli->lli_sai->sai_thread; +/* + * deauthorize opened dir handle @key to statahead, and notify statahead thread + * to quit if it's running. + */ +void ll_deauthorize_statahead(struct inode *dir, void *key) +{ + struct ll_inode_info *lli = ll_i2info(dir); + struct ll_statahead_info *sai; - if (!thread_is_stopped(thread)) { - thread_set_flags(thread, SVC_STOPPING); - spin_unlock(&lli->lli_sa_lock); - wake_up(&thread->t_ctl_waitq); + LASSERT(lli->lli_opendir_key == key); + LASSERT(lli->lli_opendir_pid != 0); - 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); - } + CDEBUG(D_READA, "deauthorize statahead for "DFID"\n", + PFID(&lli->lli_fid)); + spin_lock(&lli->lli_sa_lock); + lli->lli_opendir_key = NULL; + lli->lli_opendir_pid = 0; + lli->lli_sa_enabled = 0; + sai = lli->lli_sai; + if (sai != NULL && thread_is_running(&sai->sai_thread)) { /* - * Put the ref which was held when first statahead_enter. - * It maybe not the last ref for some statahead requests - * maybe inflight. + * statahead thread may not quit yet because it needs to cache + * entries, now it's time to tell it to quit. + * + * In case sai is released, wake_up() is called inside spinlock, + * so we have to call smp_mb() explicitely to serialize ops. */ - ll_sai_put(lli->lli_sai); - } else { - lli->lli_opendir_pid = 0; - spin_unlock(&lli->lli_sa_lock); + thread_set_flags(&sai->sai_thread, SVC_STOPPING); + smp_mb(); + wake_up(&sai->sai_thread.t_ctl_waitq); } + 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 + /** + * not first dirent, or is "." + */ + LS_NOT_FIRST_DE = 0, + /** + * the first non-hidden dirent + */ + LS_FIRST_DE, + /** + * the first hidden dirent, that is "." + */ + LS_FIRST_DOT_DE }; +/* file is first dirent under @dir */ static int is_first_dirent(struct inode *dir, struct dentry *dentry) { struct ll_dir_chain chain; @@ -1380,7 +1280,7 @@ static int is_first_dirent(struct inode *dir, struct dentry *dentry) struct md_op_data *op_data; int dot_de; struct page *page = NULL; - int rc = LS_NONE_FIRST_DE; + int rc = LS_NOT_FIRST_DE; __u64 pos = 0; ENTRY; @@ -1391,8 +1291,6 @@ static int is_first_dirent(struct inode *dir, struct dentry *dentry) /** *FIXME choose the start offset of the readdir */ - op_data->op_stripe_offset = 0; - op_data->op_max_pages = ll_i2sbi(dir)->ll_md_brw_pages; ll_dir_chain_init(&chain); page = ll_get_dir_page(dir, op_data, 0, &chain); @@ -1405,9 +1303,8 @@ static int is_first_dirent(struct inode *dir, struct dentry *dentry) struct ll_inode_info *lli = ll_i2info(dir); rc = PTR_ERR(page); - CERROR("%s: reading dir "DFID" at "LPU64 - "opendir_pid = %u : rc = %d\n", - ll_get_fsname(dir->i_sb, NULL, 0), + CERROR("%s: reading dir "DFID" at %llu opendir_pid = %u : rc = %d\n", + ll_i2sbi(dir)->ll_fsname, PFID(ll_inode2fid(dir)), pos, lli->lli_opendir_pid, rc); break; @@ -1460,7 +1357,7 @@ static int is_first_dirent(struct inode *dir, struct dentry *dentry) if (target->len != namelen || memcmp(target->name, name, namelen) != 0) - rc = LS_NONE_FIRST_DE; + rc = LS_NOT_FIRST_DE; else if (!dot_de) rc = LS_FIRST_DE; else @@ -1493,267 +1390,274 @@ out: return rc; } -static void -ll_sai_unplug(struct ll_statahead_info *sai, struct ll_sa_entry *entry) +/** + * revalidate @dentryp from statahead cache + * + * \param[in] dir parent directory + * \param[in] sai sai structure + * \param[out] dentryp pointer to dentry which will be revalidated + * \param[in] unplug unplug statahead window only (normally for negative + * dentry) + * \retval 1 on success, dentry is saved in @dentryp + * \retval 0 if revalidation failed (no proper lock on client) + * \retval negative number upon error + */ +static int revalidate_statahead_dentry(struct inode *dir, + struct ll_statahead_info *sai, + struct dentry **dentryp, + bool unplug) { - 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); + struct sa_entry *entry = NULL; + struct ll_dentry_data *ldd; + struct ll_inode_info *lli = ll_i2info(dir); + int rc = 0; + ENTRY; - 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\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 ((*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); } } - if (!thread_is_stopped(thread)) - wake_up(&thread->t_ctl_waitq); + if (unplug) + GOTO(out, rc = 1); - EXIT; -} + entry = sa_get(sai, &(*dentryp)->d_name); + if (entry == NULL) + GOTO(out, rc = -EAGAIN); -/** - * 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 }; - struct task_struct *task; - int rc = 0; - struct ll_inode_info *plli; - ENTRY; + /* if statahead is busy in readdir, help it do post-work */ + if (!sa_ready(entry) && sai->sai_in_readpage) + sa_handle_callback(sai); + + if (!sa_ready(entry)) { + spin_lock(&lli->lli_sa_lock); + sai->sai_index_wait = entry->se_index; + spin_unlock(&lli->lli_sa_lock); + rc = wait_event_idle_timeout(sai->sai_waitq, sa_ready(entry), + cfs_time_seconds(30)); + if (rc == 0) { + /* + * entry may not be ready, so it may be used by inflight + * statahead RPC, don't free it. + */ + entry = NULL; + GOTO(out, rc = -EAGAIN); + } + } - 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) { - 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 ((*dentryp)->d_inode != inode) { - /* revalidate, but inode is recreated */ - CDEBUG(D_READA, - "%s: stale dentry %.*s inode " - DFID", statahead inode "DFID - "\n", - ll_get_fsname((*dentryp)->d_inode->i_sb, NULL, 0), - (*dentryp)->d_name.len, - (*dentryp)->d_name.name, - PFID(ll_inode2fid((*dentryp)->d_inode)), - PFID(ll_inode2fid(inode))); + /* + * We need to see the value that was set immediately before we + * were woken up. + */ + if (smp_load_acquire(&entry->se_state) == SA_ENTRY_SUCC && + entry->se_inode) { + struct inode *inode = entry->se_inode; + struct lookup_intent it = { .it_op = IT_GETATTR, + .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) { + struct dentry *alias; + + alias = ll_splice_alias(inode, *dentryp); + if (IS_ERR(alias)) { ll_intent_release(&it); - ll_sai_unplug(sai, entry); - RETURN(-ESTALE); - } else { - iput(inode); + GOTO(out, rc = PTR_ERR(alias)); } + *dentryp = alias; + /* statahead prepared this inode, transfer inode + * refcount from sa_entry to dentry */ entry->se_inode = NULL; + } else if ((*dentryp)->d_inode != inode) { + /* revalidate, but inode is recreated */ + CDEBUG(D_READA, + "%s: stale dentry %.*s inode " + DFID", statahead inode "DFID + "\n", + ll_i2sbi(inode)->ll_fsname, + (*dentryp)->d_name.len, + (*dentryp)->d_name.name, + PFID(ll_inode2fid((*dentryp)->d_inode)), + PFID(ll_inode2fid(inode))); + ll_intent_release(&it); + GOTO(out, rc = -ESTALE); + } - if ((bits & MDS_INODELOCK_LOOKUP) && - d_lustre_invalid(*dentryp)) - d_lustre_revalidate(*dentryp); - ll_intent_release(&it); - } - } + if ((bits & MDS_INODELOCK_LOOKUP) && + d_lustre_invalid(*dentryp)) + d_lustre_revalidate(*dentryp); + ll_intent_release(&it); + } + } +out: + /* + * statahead cached sa_entry can be used only once, and will be killed + * right after use, so if lookup/revalidate accessed statahead cache, + * set dentry ldd_sa_generation to parent lli_sa_generation, later if we + * stat this file again, we know we've done statahead before, see + * dentry_may_statahead(). + */ + ldd = ll_d2d(*dentryp); + /* ldd can be NULL if llite lookup failed. */ + if (ldd != NULL) + ldd->lld_sa_generation = lli->lli_sa_generation; + sa_put(sai, entry); - ll_sai_unplug(sai, entry); - RETURN(rc); - } + 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); - } +/** + * start statahead thread + * + * \param[in] dir parent directory + * \param[in] dentry dentry that triggers statahead, normally the first + * dirent under @dir + * \retval -EAGAIN on success, because when this function is + * called, it's already in lookup call, so client should + * do it itself instead of waiting for statahead thread + * to do it asynchronously. + * \retval negative number upon error + */ +static int start_statahead_thread(struct inode *dir, struct dentry *dentry) +{ + struct ll_inode_info *lli = ll_i2info(dir); + struct ll_statahead_info *sai = NULL; + struct dentry *parent = dentry->d_parent; + struct ptlrpc_thread *thread; + struct task_struct *task; + struct ll_sb_info *sbi = ll_i2sbi(parent->d_inode); + int first = LS_FIRST_DE; + int rc = 0; + ENTRY; - /* 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); - } + /* I am the "lli_opendir_pid" owner, only me can set "lli_sai". */ + first = is_first_dirent(dir, dentry); + if (first == LS_NOT_FIRST_DE) + /* It is not "ls -{a}l" operation, no need statahead for it. */ + GOTO(out, rc = -EFAULT); + + if (unlikely(atomic_inc_return(&sbi->ll_sa_running) > + sbi->ll_sa_running_max)) { + CDEBUG(D_READA, + "Too many concurrent statahead instances, " + "avoid new statahead instance temporarily.\n"); + GOTO(out, rc = -EMFILE); + } - CDEBUG(D_READA, "start statahead thread: sai %p, parent %.*s\n", - sai, parent->d_name.len, parent->d_name.name); + sai = ll_sai_alloc(parent); + if (sai == NULL) + GOTO(out, rc = -ENOMEM); - /* 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; + sai->sai_ls_all = (first == LS_FIRST_DOT_DE); + + /* if current lli_opendir_key was deauthorized, or dir re-opened by + * another process, don't start statahead, otherwise the newly spawned + * statahead thread won't be notified to quit. */ + spin_lock(&lli->lli_sa_lock); + if (unlikely(lli->lli_sai != NULL || + lli->lli_opendir_key == NULL || + lli->lli_opendir_pid != current->pid)) { + spin_unlock(&lli->lli_sa_lock); + GOTO(out, rc = -EPERM); + } + lli->lli_sai = sai; + spin_unlock(&lli->lli_sa_lock); + + CDEBUG(D_READA, "start statahead 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_statahead_thread, parent, "ll_sa_%u", - plli->lli_opendir_pid); + lli->lli_opendir_pid); thread = &sai->sai_thread; if (IS_ERR(task)) { + spin_lock(&lli->lli_sa_lock); + lli->lli_sai = NULL; + spin_unlock(&lli->lli_sa_lock); rc = PTR_ERR(task); - CERROR("cannot 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); - } + CERROR("can't start ll_sa thread, rc: %d\n", rc); + GOTO(out, rc); + } - l_wait_event(thread->t_ctl_waitq, - thread_is_running(thread) || thread_is_stopped(thread), - &lwi); + wait_event_idle(thread->t_ctl_waitq, + thread_is_running(thread) || thread_is_stopped(thread)); ll_sai_put(sai); - /* - * We don't stat-ahead for the first dirent since we are already in - * lookup. - */ - RETURN(-EAGAIN); + /* + * 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); + /* once we start statahead thread failed, disable statahead so that + * subsequent stat won't waste time to try it. */ spin_lock(&lli->lli_sa_lock); - lli->lli_opendir_key = NULL; - lli->lli_opendir_pid = 0; + if (lli->lli_opendir_pid == current->pid) + lli->lli_sa_enabled = 0; spin_unlock(&lli->lli_sa_lock); - return rc; + + if (sai != NULL) + ll_sai_free(sai); + if (first != LS_NOT_FIRST_DE) + atomic_dec(&sbi->ll_sa_running); + + RETURN(rc); +} + +/** + * statahead entry function, this is called when client getattr on a file, it + * will start statahead thread if this is the first dir entry, else revalidate + * dentry from statahead cache. + * + * \param[in] dir parent directory + * \param[out] dentryp dentry to getattr + * \param[in] unplug unplug statahead window only (normally for negative + * dentry) + * \retval 1 on success + * \retval 0 revalidation from statahead cache failed, caller needs + * to getattr from server directly + * \retval negative number on error, caller often ignores this and + * then getattr from server + */ +int ll_statahead(struct inode *dir, struct dentry **dentryp, bool unplug) +{ + struct ll_statahead_info *sai; + + sai = ll_sai_get(dir); + if (sai != NULL) { + int rc; + + rc = revalidate_statahead_dentry(dir, sai, dentryp, unplug); + CDEBUG(D_READA, "revalidate statahead %.*s: %d.\n", + (*dentryp)->d_name.len, (*dentryp)->d_name.name, rc); + ll_sai_put(sai); + return rc; + } + return start_statahead_thread(dir, *dentryp); }