diff options
Diffstat (limited to 'include/linux/dcache.h')
| -rw-r--r-- | include/linux/dcache.h | 186 |
1 files changed, 110 insertions, 76 deletions
diff --git a/include/linux/dcache.h b/include/linux/dcache.h index 45bff10d3773..4b1ff99608e0 100644 --- a/include/linux/dcache.h +++ b/include/linux/dcache.h @@ -57,7 +57,8 @@ struct qstr { }; #define QSTR_INIT(n,l) { { { .len = l } }, .name = n } -#define QSTR(n) (struct qstr)QSTR_INIT(n, strlen(n)) +#define QSTR_LEN(n,l) (struct qstr)QSTR_INIT(n,l) +#define QSTR(n) QSTR_LEN(n, strlen(n)) extern const struct qstr empty_name; extern const struct qstr slash_name; @@ -87,6 +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 */ @@ -94,7 +96,10 @@ struct dentry { seqcount_spinlock_t d_seq; /* per dentry seqlock */ struct hlist_bl_node d_hash; /* lookup hash list */ struct dentry *d_parent; /* parent directory */ - struct qstr d_name; + union { + struct qstr __d_name; /* for use ONLY in fs/dcache.c */ + const struct qstr d_name; + }; struct inode *d_inode; /* Where the name belongs to - NULL is * negative */ union shortname_store d_shortname; @@ -111,20 +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; + }; }; /* @@ -173,65 +186,62 @@ struct dentry_operations { */ /* d_flags entries */ -#define DCACHE_OP_HASH BIT(0) -#define DCACHE_OP_COMPARE BIT(1) -#define DCACHE_OP_REVALIDATE BIT(2) -#define DCACHE_OP_DELETE BIT(3) -#define DCACHE_OP_PRUNE BIT(4) - -#define DCACHE_DISCONNECTED BIT(5) - /* This dentry is possibly not currently connected to the dcache tree, in - * which case its parent will either be itself, or will have this flag as - * well. nfsd will not use a dentry with this bit set, but will first - * endeavour to clear the bit either by discovering that it is connected, - * or by performing lookup operations. Any filesystem which supports - * nfsd_operations MUST have a lookup function which, if it finds a - * directory inode with a DCACHE_DISCONNECTED dentry, will d_move that - * dentry into place and return that dentry rather than the passed one, - * typically using d_splice_alias. */ - -#define DCACHE_REFERENCED BIT(6) /* Recently used, don't discard. */ - -#define DCACHE_DONTCACHE BIT(7) /* Purge from memory on final dput() */ - -#define DCACHE_CANT_MOUNT BIT(8) -#define DCACHE_GENOCIDE BIT(9) -#define DCACHE_SHRINK_LIST BIT(10) - -#define DCACHE_OP_WEAK_REVALIDATE BIT(11) - -#define DCACHE_NFSFS_RENAMED BIT(12) - /* this dentry has been "silly renamed" and has to be deleted on the last - * dput() */ -#define DCACHE_FSNOTIFY_PARENT_WATCHED BIT(13) - /* Parent inode is watched by some fsnotify listener */ - -#define DCACHE_DENTRY_KILLED BIT(14) - -#define DCACHE_MOUNTED BIT(15) /* is a mountpoint */ -#define DCACHE_NEED_AUTOMOUNT BIT(16) /* handle automount on this dir */ -#define DCACHE_MANAGE_TRANSIT BIT(17) /* manage transit from this dirent */ +enum dentry_flags { + DCACHE_OP_HASH = BIT(0), + DCACHE_OP_COMPARE = BIT(1), + DCACHE_OP_REVALIDATE = BIT(2), + DCACHE_OP_DELETE = BIT(3), + DCACHE_OP_PRUNE = BIT(4), + /* + * This dentry is possibly not currently connected to the dcache tree, + * in which case its parent will either be itself, or will have this + * flag as well. nfsd will not use a dentry with this bit set, but will + * first endeavour to clear the bit either by discovering that it is + * connected, or by performing lookup operations. Any filesystem which + * supports nfsd_operations MUST have a lookup function which, if it + * finds a directory inode with a DCACHE_DISCONNECTED dentry, will + * d_move that dentry into place and return that dentry rather than the + * passed one, typically using d_splice_alias. + */ + DCACHE_DISCONNECTED = BIT(5), + 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), + /* + * this dentry has been "silly renamed" and has to be deleted on the + * last dput() + */ + DCACHE_NFSFS_RENAMED = BIT(12), + DCACHE_FSNOTIFY_PARENT_WATCHED = BIT(13), /* Parent inode is watched by some fsnotify listener */ + DCACHE_DENTRY_KILLED = BIT(14), + DCACHE_MOUNTED = BIT(15), /* is a mountpoint */ + DCACHE_NEED_AUTOMOUNT = BIT(16), /* handle automount on this dir */ + DCACHE_MANAGE_TRANSIT = BIT(17), /* manage transit from this dirent */ + DCACHE_LRU_LIST = BIT(18), + DCACHE_ENTRY_TYPE = (7 << 19), /* bits 19..21 are for storing type: */ + DCACHE_MISS_TYPE = (0 << 19), /* Negative dentry */ + DCACHE_WHITEOUT_TYPE = (1 << 19), /* Whiteout dentry (stop pathwalk) */ + DCACHE_DIRECTORY_TYPE = (2 << 19), /* Normal directory */ + DCACHE_AUTODIR_TYPE = (3 << 19), /* Lookupless directory (presumed automount) */ + DCACHE_REGULAR_TYPE = (4 << 19), /* Regular file type */ + DCACHE_SPECIAL_TYPE = (5 << 19), /* Other file type */ + DCACHE_SYMLINK_TYPE = (6 << 19), /* Symlink */ + DCACHE_NOKEY_NAME = BIT(22), /* Encrypted name encoded without key */ + DCACHE_OP_REAL = BIT(23), + DCACHE_PAR_LOOKUP = BIT(24), /* being looked up (with parent locked shared) */ + DCACHE_DENTRY_CURSOR = BIT(25), + DCACHE_NORCU = BIT(26), /* No RCU delay for freeing */ + DCACHE_PERSISTENT = BIT(27) +}; + #define DCACHE_MANAGED_DENTRY \ (DCACHE_MOUNTED|DCACHE_NEED_AUTOMOUNT|DCACHE_MANAGE_TRANSIT) -#define DCACHE_LRU_LIST BIT(18) - -#define DCACHE_ENTRY_TYPE (7 << 19) /* bits 19..21 are for storing type: */ -#define DCACHE_MISS_TYPE (0 << 19) /* Negative dentry */ -#define DCACHE_WHITEOUT_TYPE (1 << 19) /* Whiteout dentry (stop pathwalk) */ -#define DCACHE_DIRECTORY_TYPE (2 << 19) /* Normal directory */ -#define DCACHE_AUTODIR_TYPE (3 << 19) /* Lookupless directory (presumed automount) */ -#define DCACHE_REGULAR_TYPE (4 << 19) /* Regular file type */ -#define DCACHE_SPECIAL_TYPE (5 << 19) /* Other file type */ -#define DCACHE_SYMLINK_TYPE (6 << 19) /* Symlink */ - -#define DCACHE_NOKEY_NAME BIT(22) /* Encrypted name encoded without key */ -#define DCACHE_OP_REAL BIT(23) - -#define DCACHE_PAR_LOOKUP BIT(24) /* being looked up (with parent locked shared) */ -#define DCACHE_DENTRY_CURSOR BIT(25) -#define DCACHE_NORCU BIT(26) /* No RCU delay for freeing */ - extern seqlock_t rename_lock; /* @@ -242,14 +252,15 @@ extern void d_instantiate_new(struct dentry *, struct inode *); extern void __d_drop(struct dentry *dentry); extern void d_drop(struct dentry *dentry); extern void d_delete(struct dentry *); -extern void d_set_d_op(struct dentry *dentry, const struct dentry_operations *op); /* 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 *, + const struct dentry_operations *); extern struct dentry * d_add_ci(struct dentry *, struct inode *, struct qstr *); extern bool d_same_name(const struct dentry *dentry, const struct dentry *parent, const struct qstr *name); @@ -264,10 +275,13 @@ 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 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 *); @@ -287,7 +301,6 @@ extern void d_exchange(struct dentry *, struct dentry *); extern struct dentry *d_ancestor(struct dentry *, struct dentry *); extern struct dentry *d_lookup(const struct dentry *, const struct qstr *); -extern struct dentry *d_hash_and_lookup(struct dentry *, struct qstr *); static inline unsigned d_count(const struct dentry *dentry) { @@ -352,6 +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); /** @@ -519,12 +550,7 @@ static inline int simple_positive(const struct dentry *dentry) return d_really_is_positive(dentry) && !d_unhashed(dentry); } -extern int sysctl_vfs_cache_pressure; - -static inline unsigned long vfs_pressure_ratio(unsigned long val) -{ - return mult_frac(val, sysctl_vfs_cache_pressure, 100); -} +unsigned long vfs_pressure_ratio(unsigned long val); /** * d_inode - Get the actual inode of this dentry @@ -615,4 +641,12 @@ static inline struct dentry *d_next_sibling(const struct dentry *dentry) return hlist_entry_safe(dentry->d_sib.next, struct dentry, d_sib); } +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 */ |