diff options
Diffstat (limited to 'include/linux/dcache.h')
| -rw-r--r-- | include/linux/dcache.h | 56 |
1 files changed, 45 insertions, 11 deletions
diff --git a/include/linux/dcache.h b/include/linux/dcache.h index 898c60d21c92..4b1ff99608e0 100644 --- a/include/linux/dcache.h +++ b/include/linux/dcache.h @@ -88,6 +88,7 @@ union shortname_store { #define d_lock d_lockref.lock #define d_iname d_shortname.string +struct completion_list; struct dentry { /* RCU lookup touched fields */ @@ -115,20 +116,28 @@ struct dentry { * possible! */ - union { - struct list_head d_lru; /* LRU list */ - wait_queue_head_t *d_wait; /* in-lookup ones only */ - }; + struct list_head d_lru; /* LRU list */ struct hlist_node d_sib; /* child of parent list */ struct hlist_head d_children; /* our children */ /* - * d_alias and d_rcu can share memory + * the following members can share memory - their uses are + * mutually exclusive. */ union { - struct hlist_node d_alias; /* inode alias list */ - struct hlist_bl_node d_in_lookup_hash; /* only for in-lookup ones */ + /* positives: inode alias list */ + struct hlist_node d_alias; + /* in-lookup ones (all negative, live): hash chain */ + struct hlist_bl_node d_in_lookup_hash; + /* killed ones: (already negative) used to schedule freeing */ struct rcu_head d_rcu; - } d_u; + /* + * live non-in-lookup negatives: used if shrink_dcache_tree() + * races with eviction by another thread and needs to wait for + * this dentry to get killed . Remains NULL for almost all + * negative dentries. + */ + struct completion_list *waiters; + }; }; /* @@ -198,6 +207,9 @@ enum dentry_flags { DCACHE_REFERENCED = BIT(6), /* Recently used, don't discard. */ DCACHE_DONTCACHE = BIT(7), /* Purge from memory on final dput() */ DCACHE_CANT_MOUNT = BIT(8), + DCACHE_LOOKUP_WAITERS = BIT(9), /* A thread is waiting for + * PAR_LOOKUP to clear + */ DCACHE_SHRINK_LIST = BIT(10), DCACHE_OP_WEAK_REVALIDATE = BIT(11), /* @@ -244,8 +256,7 @@ extern void d_delete(struct dentry *); /* allocate/de-allocate */ extern struct dentry * d_alloc(struct dentry *, const struct qstr *); extern struct dentry * d_alloc_anon(struct super_block *); -extern struct dentry * d_alloc_parallel(struct dentry *, const struct qstr *, - wait_queue_head_t *); +extern struct dentry * d_alloc_parallel(struct dentry *, const struct qstr *); extern struct dentry * d_splice_alias(struct inode *, struct dentry *); /* weird procfs mess; *NOT* exported */ extern struct dentry * d_splice_alias_ops(struct inode *, struct dentry *, @@ -264,11 +275,12 @@ extern void d_invalidate(struct dentry *); extern struct dentry * d_make_root(struct inode *); extern void d_mark_tmpfile(struct file *, struct inode *); +int d_mark_tmpfile_name(struct file *file, const struct qstr *name); extern void d_tmpfile(struct file *, struct inode *); extern struct dentry *d_find_alias(struct inode *); extern void d_prune_aliases(struct inode *); -extern void d_dispose_if_unused(struct dentry *, struct list_head *); +extern bool __move_to_shrink_list(struct dentry *, struct list_head *); extern void shrink_dentry_list(struct list_head *); extern struct dentry *d_find_alias_rcu(struct inode *); @@ -353,6 +365,24 @@ static inline struct dentry *dget(struct dentry *dentry) return dentry; } +/* dentry->d_inode->i_lock must be held by caller */ +static inline bool dget_alias_ilocked(struct dentry *dentry) +{ + if (likely(!(READ_ONCE(dentry->d_flags) & DCACHE_NORCU))) { + lockref_get(&dentry->d_lockref); + return true; + } + // NORCU dentries with zero refcount MUST NOT be grabbed + spin_lock(&dentry->d_lock); + if (dentry->d_lockref.count > 0) { + dget_dlock(dentry); + spin_unlock(&dentry->d_lock); + return true; + } + spin_unlock(&dentry->d_lock); + return false; +} + extern struct dentry *dget_parent(struct dentry *dentry); /** @@ -615,4 +645,8 @@ void set_default_d_op(struct super_block *, const struct dentry_operations *); struct dentry *d_make_persistent(struct dentry *, struct inode *); void d_make_discardable(struct dentry *dentry); +/* inode->i_lock must be held over that */ +#define for_each_alias(dentry, inode) \ + hlist_for_each_entry(dentry, &(inode)->i_dentry, d_alias) + #endif /* __LINUX_DCACHE_H */ |