diff options
Diffstat (limited to 'include/linux/dcache.h')
| -rw-r--r-- | include/linux/dcache.h | 297 |
1 files changed, 148 insertions, 149 deletions
diff --git a/include/linux/dcache.h b/include/linux/dcache.h index 6f95c3300cbb..e29823c701ac 100644 --- a/include/linux/dcache.h +++ b/include/linux/dcache.h @@ -4,6 +4,7 @@ #include <linux/atomic.h> #include <linux/list.h> +#include <linux/math.h> #include <linux/rculist.h> #include <linux/rculist_bl.h> #include <linux/spinlock.h> @@ -15,6 +16,7 @@ #include <linux/wait.h> struct path; +struct file; struct vfsmount; /* @@ -55,19 +57,12 @@ struct qstr { }; #define QSTR_INIT(n,l) { { { .len = l } }, .name = 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; - -struct dentry_stat_t { - long nr_dentry; - long nr_unused; - long age_limit; /* age in seconds */ - long want_pages; /* pages requested by system */ - long nr_negative; /* # of unused negative dentries */ - long dummy; /* Reserved for future use */ -}; -extern struct dentry_stat_t dentry_stat; +extern const struct qstr dotdot_name; /* * Try to keep struct dentry aligned on 64 byte cachelines (this will @@ -75,16 +70,24 @@ extern struct dentry_stat_t dentry_stat; * large memory footprint increase). */ #ifdef CONFIG_64BIT -# define DNAME_INLINE_LEN 32 /* 192 bytes */ +# define DNAME_INLINE_WORDS 5 /* 192 bytes */ #else # ifdef CONFIG_SMP -# define DNAME_INLINE_LEN 36 /* 128 bytes */ +# define DNAME_INLINE_WORDS 9 /* 128 bytes */ # else -# define DNAME_INLINE_LEN 40 /* 128 bytes */ +# define DNAME_INLINE_WORDS 11 /* 128 bytes */ # endif #endif +#define DNAME_INLINE_LEN (DNAME_INLINE_WORDS*sizeof(unsigned long)) + +union shortname_store { + unsigned char string[DNAME_INLINE_LEN]; + unsigned long words[DNAME_INLINE_WORDS]; +}; + #define d_lock d_lockref.lock +#define d_iname d_shortname.string struct dentry { /* RCU lookup touched fields */ @@ -95,21 +98,26 @@ struct dentry { struct qstr d_name; struct inode *d_inode; /* Where the name belongs to - NULL is * negative */ - unsigned char d_iname[DNAME_INLINE_LEN]; /* small names */ + union shortname_store d_shortname; + /* --- cacheline 1 boundary (64 bytes) was 32 bytes ago --- */ /* Ref lookup also touches following */ - struct lockref d_lockref; /* per-dentry lock and refcount */ const struct dentry_operations *d_op; struct super_block *d_sb; /* The root of the dentry tree */ unsigned long d_time; /* used by d_revalidate */ void *d_fsdata; /* fs-specific data */ + /* --- cacheline 2 boundary (128 bytes) --- */ + struct lockref d_lockref; /* per-dentry lock and refcount + * keep separate from RCU lookup area if + * possible! + */ union { struct list_head d_lru; /* LRU list */ wait_queue_head_t *d_wait; /* in-lookup ones only */ }; - struct list_head d_child; /* child of parent list */ - struct list_head d_subdirs; /* our children */ + struct hlist_node d_sib; /* child of parent list */ + struct hlist_head d_children; /* our children */ /* * d_alias and d_rcu can share memory */ @@ -118,7 +126,7 @@ struct dentry { struct hlist_bl_node d_in_lookup_hash; /* only for in-lookup ones */ struct rcu_head d_rcu; } d_u; -} __randomize_layout; +}; /* * dentry->d_lock spinlock nesting subclasses: @@ -132,8 +140,14 @@ enum dentry_d_lock_class DENTRY_D_LOCK_NESTED }; +enum d_real_type { + D_REAL_DATA, + D_REAL_METADATA, +}; + struct dentry_operations { - int (*d_revalidate)(struct dentry *, unsigned int); + int (*d_revalidate)(struct inode *, const struct qstr *, + struct dentry *, unsigned int); int (*d_weak_revalidate)(struct dentry *, unsigned int); int (*d_hash)(const struct dentry *, struct qstr *); int (*d_compare)(const struct dentry *, @@ -146,7 +160,9 @@ struct dentry_operations { char *(*d_dname)(struct dentry *, char *, int); struct vfsmount *(*d_automount)(struct path *); int (*d_manage)(const struct path *, bool); - struct dentry *(*d_real)(struct dentry *, const struct inode *); + struct dentry *(*d_real)(struct dentry *, enum d_real_type type); + bool (*d_unalias_trylock)(const struct dentry *); + void (*d_unalias_unlock)(const struct dentry *); } ____cacheline_aligned; /* @@ -158,68 +174,59 @@ struct dentry_operations { */ /* d_flags entries */ -#define DCACHE_OP_HASH 0x00000001 -#define DCACHE_OP_COMPARE 0x00000002 -#define DCACHE_OP_REVALIDATE 0x00000004 -#define DCACHE_OP_DELETE 0x00000008 -#define DCACHE_OP_PRUNE 0x00000010 - -#define DCACHE_DISCONNECTED 0x00000020 - /* 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 0x00000040 /* Recently used, don't discard. */ - -#define DCACHE_DONTCACHE 0x00000080 /* Purge from memory on final dput() */ - -#define DCACHE_CANT_MOUNT 0x00000100 -#define DCACHE_GENOCIDE 0x00000200 -#define DCACHE_SHRINK_LIST 0x00000400 - -#define DCACHE_OP_WEAK_REVALIDATE 0x00000800 - -#define DCACHE_NFSFS_RENAMED 0x00001000 - /* this dentry has been "silly renamed" and has to be deleted on the last - * dput() */ -#define DCACHE_COOKIE 0x00002000 /* For use by dcookie subsystem */ -#define DCACHE_FSNOTIFY_PARENT_WATCHED 0x00004000 - /* Parent inode is watched by some fsnotify listener */ - -#define DCACHE_DENTRY_KILLED 0x00008000 - -#define DCACHE_MOUNTED 0x00010000 /* is a mountpoint */ -#define DCACHE_NEED_AUTOMOUNT 0x00020000 /* handle automount on this dir */ -#define DCACHE_MANAGE_TRANSIT 0x00040000 /* 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_GENOCIDE = BIT(9), + 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 */ +}; + #define DCACHE_MANAGED_DENTRY \ (DCACHE_MOUNTED|DCACHE_NEED_AUTOMOUNT|DCACHE_MANAGE_TRANSIT) -#define DCACHE_LRU_LIST 0x00080000 - -#define DCACHE_ENTRY_TYPE 0x00700000 -#define DCACHE_MISS_TYPE 0x00000000 /* Negative dentry (maybe fallthru to nowhere) */ -#define DCACHE_WHITEOUT_TYPE 0x00100000 /* Whiteout dentry (stop pathwalk) */ -#define DCACHE_DIRECTORY_TYPE 0x00200000 /* Normal directory */ -#define DCACHE_AUTODIR_TYPE 0x00300000 /* Lookupless directory (presumed automount) */ -#define DCACHE_REGULAR_TYPE 0x00400000 /* Regular file type (or fallthru to such) */ -#define DCACHE_SPECIAL_TYPE 0x00500000 /* Other file type (or fallthru to such) */ -#define DCACHE_SYMLINK_TYPE 0x00600000 /* Symlink (or fallthru to such) */ - -#define DCACHE_MAY_FREE 0x00800000 -#define DCACHE_FALLTHRU 0x01000000 /* Fall through to lower layer */ -#define DCACHE_NOKEY_NAME 0x02000000 /* Encrypted name encoded without key */ -#define DCACHE_OP_REAL 0x04000000 - -#define DCACHE_PAR_LOOKUP 0x10000000 /* being looked up (with parent locked shared) */ -#define DCACHE_DENTRY_CURSOR 0x20000000 -#define DCACHE_NORCU 0x40000000 /* No RCU delay for freeing */ - extern seqlock_t rename_lock; /* @@ -227,8 +234,6 @@ extern seqlock_t rename_lock; */ extern void d_instantiate(struct dentry *, struct inode *); extern void d_instantiate_new(struct dentry *, struct inode *); -extern struct dentry * d_instantiate_unique(struct dentry *, struct inode *); -extern struct dentry * d_instantiate_anon(struct dentry *, struct inode *); extern void __d_drop(struct dentry *dentry); extern void d_drop(struct dentry *dentry); extern void d_delete(struct dentry *); @@ -241,26 +246,26 @@ extern struct dentry * d_alloc_parallel(struct dentry *, const struct qstr *, wait_queue_head_t *); extern struct dentry * d_splice_alias(struct inode *, struct dentry *); extern struct dentry * d_add_ci(struct dentry *, struct inode *, struct qstr *); -extern struct dentry * d_exact_alias(struct dentry *, struct inode *); +extern bool d_same_name(const struct dentry *dentry, const struct dentry *parent, + const struct qstr *name); extern struct dentry *d_find_any_alias(struct inode *inode); extern struct dentry * d_obtain_alias(struct inode *); extern struct dentry * d_obtain_root(struct inode *); extern void shrink_dcache_sb(struct super_block *); extern void shrink_dcache_parent(struct dentry *); -extern void shrink_dcache_for_umount(struct super_block *); extern void d_invalidate(struct dentry *); /* only used at mount-time */ extern struct dentry * d_make_root(struct inode *); -/* <clickety>-<click> the ramfs-type tree */ -extern void d_genocide(struct dentry *); - -extern void d_tmpfile(struct dentry *, struct inode *); +extern void d_mark_tmpfile(struct file *, struct inode *); +extern void d_tmpfile(struct file *, struct inode *); extern struct dentry *d_find_alias(struct inode *); extern void d_prune_aliases(struct inode *); +extern struct dentry *d_find_alias_rcu(struct inode *); + /* test whether we have any submounts in a subdir tree */ extern int path_has_submounts(const struct path *); @@ -276,47 +281,64 @@ extern void d_move(struct dentry *, struct dentry *); extern void d_exchange(struct dentry *, struct dentry *); extern struct dentry *d_ancestor(struct dentry *, struct dentry *); -/* appendix may either be NULL or be used for transname suffixes */ extern struct dentry *d_lookup(const struct dentry *, const struct qstr *); -extern struct dentry *d_hash_and_lookup(struct dentry *, struct qstr *); -extern struct dentry *__d_lookup(const struct dentry *, const struct qstr *); -extern struct dentry *__d_lookup_rcu(const struct dentry *parent, - const struct qstr *name, unsigned *seq); static inline unsigned d_count(const struct dentry *dentry) { return dentry->d_lockref.count; } +ino_t d_parent_ino(struct dentry *dentry); + /* * helper function for dentry_operations.d_dname() members */ -extern __printf(4, 5) -char *dynamic_dname(struct dentry *, char *, int, const char *, ...); +extern __printf(3, 4) +char *dynamic_dname(char *, int, const char *, ...); extern char *__d_path(const struct path *, const struct path *, char *, int); extern char *d_absolute_path(const struct path *, char *, int); extern char *d_path(const struct path *, char *, int); -extern char *dentry_path_raw(struct dentry *, char *, int); -extern char *dentry_path(struct dentry *, char *, int); +extern char *dentry_path_raw(const struct dentry *, char *, int); +extern char *dentry_path(const struct dentry *, char *, int); /* Allocation counts.. */ /** - * dget, dget_dlock - get a reference to a dentry - * @dentry: dentry to get a reference to + * dget_dlock - get a reference to a dentry + * @dentry: dentry to get a reference to * - * Given a dentry or %NULL pointer increment the reference count - * if appropriate and return the dentry. A dentry will not be - * destroyed when it has references. + * Given a live dentry, increment the reference count and return the dentry. + * Caller must hold @dentry->d_lock. Making sure that dentry is alive is + * caller's resonsibility. There are many conditions sufficient to guarantee + * that; e.g. anything with non-negative refcount is alive, so's anything + * hashed, anything positive, anyone's parent, etc. */ static inline struct dentry *dget_dlock(struct dentry *dentry) { - if (dentry) - dentry->d_lockref.count++; + dentry->d_lockref.count++; return dentry; } + +/** + * dget - get a reference to a dentry + * @dentry: dentry to get a reference to + * + * Given a dentry or %NULL pointer increment the reference count + * if appropriate and return the dentry. A dentry will not be + * destroyed when it has references. Conversely, a dentry with + * no references can disappear for any number of reasons, starting + * with memory pressure. In other words, that primitive is + * used to clone an existing reference; using it on something with + * zero refcount is a bug. + * + * NOTE: it will spin if @dentry->d_lock is held. From the deadlock + * avoidance point of view it is equivalent to spin_lock()/increment + * refcount/spin_unlock(), so calling it under @dentry->d_lock is + * always a bug; so's calling it under ->d_lock on any of its descendents. + * + */ static inline struct dentry *dget(struct dentry *dentry) { if (dentry) @@ -327,12 +349,11 @@ static inline struct dentry *dget(struct dentry *dentry) extern struct dentry *dget_parent(struct dentry *dentry); /** - * d_unhashed - is dentry hashed - * @dentry: entry to check + * d_unhashed - is dentry hashed + * @dentry: entry to check * - * Returns true if the dentry passed is not currently hashed. + * Returns true if the dentry passed is not currently hashed. */ - static inline int d_unhashed(const struct dentry *dentry) { return hlist_bl_unhashed(&dentry->d_hash); @@ -355,7 +376,7 @@ static inline void dont_mount(struct dentry *dentry) spin_unlock(&dentry->d_lock); } -extern void __d_lookup_done(struct dentry *); +extern void __d_lookup_unhash_wake(struct dentry *dentry); static inline int d_in_lookup(const struct dentry *dentry) { @@ -364,11 +385,8 @@ static inline int d_in_lookup(const struct dentry *dentry) static inline void d_lookup_done(struct dentry *dentry) { - if (unlikely(d_in_lookup(dentry))) { - spin_lock(&dentry->d_lock); - __d_lookup_done(dentry); - spin_unlock(&dentry->d_lock); - } + if (unlikely(d_in_lookup(dentry))) + __d_lookup_unhash_wake(dentry); } extern void dput(struct dentry *); @@ -495,20 +513,7 @@ static inline int simple_positive(const struct dentry *dentry) return d_really_is_positive(dentry) && !d_unhashed(dentry); } -extern void d_set_fallthru(struct dentry *dentry); - -static inline bool d_is_fallthru(const struct dentry *dentry) -{ - return dentry->d_flags & DCACHE_FALLTHRU; -} - - -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 @@ -552,41 +557,25 @@ static inline struct inode *d_backing_inode(const struct dentry *upper) } /** - * d_backing_dentry - Get upper or lower dentry we should be using - * @upper: The upper layer - * - * This is the helper that should be used to get the dentry of the inode that - * will be used if this dentry were opened as a file. It may be the upper - * dentry or it may be a lower dentry pinned by the upper. - * - * Normal filesystems should not use this to access their own dentries. - */ -static inline struct dentry *d_backing_dentry(struct dentry *upper) -{ - return upper; -} - -/** * d_real - Return the real dentry * @dentry: the dentry to query - * @inode: inode to select the dentry from multiple layers (can be NULL) + * @type: the type of real dentry (data or metadata) * * If dentry is on a union/overlay, then return the underlying, real dentry. * Otherwise return the dentry itself. * * See also: Documentation/filesystems/vfs.rst */ -static inline struct dentry *d_real(struct dentry *dentry, - const struct inode *inode) +static inline struct dentry *d_real(struct dentry *dentry, enum d_real_type type) { if (unlikely(dentry->d_flags & DCACHE_OP_REAL)) - return dentry->d_op->d_real(dentry, inode); + return dentry->d_op->d_real(dentry, type); else return dentry; } /** - * d_real_inode - Return the real inode + * d_real_inode - Return the real inode hosting the data * @dentry: The dentry to query * * If dentry is on a union/overlay, then return the underlying, real inode. @@ -595,14 +584,24 @@ static inline struct dentry *d_real(struct dentry *dentry, static inline struct inode *d_real_inode(const struct dentry *dentry) { /* This usage of d_real() results in const dentry */ - return d_backing_inode(d_real((struct dentry *) dentry, NULL)); + return d_inode(d_real((struct dentry *) dentry, D_REAL_DATA)); } struct name_snapshot { struct qstr name; - unsigned char inline_name[DNAME_INLINE_LEN]; + union shortname_store inline_name; }; void take_dentry_name_snapshot(struct name_snapshot *, struct dentry *); void release_dentry_name_snapshot(struct name_snapshot *); +static inline struct dentry *d_first_child(const struct dentry *dentry) +{ + return hlist_entry_safe(dentry->d_children.first, struct dentry, d_sib); +} + +static inline struct dentry *d_next_sibling(const struct dentry *dentry) +{ + return hlist_entry_safe(dentry->d_sib.next, struct dentry, d_sib); +} + #endif /* __LINUX_DCACHE_H */ |