cregit-Linux how code gets into the kernel

Release 4.18 fs/dcache.c

Directory: fs
/*
 * fs/dcache.c
 *
 * Complete reimplementation
 * (C) 1997 Thomas Schoebel-Theuer,
 * with heavy changes by Linus Torvalds
 */

/*
 * Notes on the allocation strategy:
 *
 * The dcache is a master of the icache - whenever a dcache entry
 * exists, the inode will always exist. "iput()" is done either when
 * the dcache entry is deleted or garbage collected.
 */

#include <linux/ratelimit.h>
#include <linux/string.h>
#include <linux/mm.h>
#include <linux/fs.h>
#include <linux/fsnotify.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/hash.h>
#include <linux/cache.h>
#include <linux/export.h>
#include <linux/security.h>
#include <linux/seqlock.h>
#include <linux/bootmem.h>
#include <linux/bit_spinlock.h>
#include <linux/rculist_bl.h>
#include <linux/list_lru.h>
#include "internal.h"
#include "mount.h"

/*
 * Usage:
 * dcache->d_inode->i_lock protects:
 *   - i_dentry, d_u.d_alias, d_inode of aliases
 * dcache_hash_bucket lock protects:
 *   - the dcache hash table
 * s_roots bl list spinlock protects:
 *   - the s_roots list (see __d_drop)
 * dentry->d_sb->s_dentry_lru_lock protects:
 *   - the dcache lru lists and counters
 * d_lock protects:
 *   - d_flags
 *   - d_name
 *   - d_lru
 *   - d_count
 *   - d_unhashed()
 *   - d_parent and d_subdirs
 *   - childrens' d_child and d_parent
 *   - d_u.d_alias, d_inode
 *
 * Ordering:
 * dentry->d_inode->i_lock
 *   dentry->d_lock
 *     dentry->d_sb->s_dentry_lru_lock
 *     dcache_hash_bucket lock
 *     s_roots lock
 *
 * If there is an ancestor relationship:
 * dentry->d_parent->...->d_parent->d_lock
 *   ...
 *     dentry->d_parent->d_lock
 *       dentry->d_lock
 *
 * If no ancestor relationship:
 * arbitrary, since it's serialized on rename_lock
 */

int sysctl_vfs_cache_pressure __read_mostly = 100;
EXPORT_SYMBOL_GPL(sysctl_vfs_cache_pressure);

__cacheline_aligned_in_smp DEFINE_SEQLOCK(rename_lock);

EXPORT_SYMBOL(rename_lock);


static struct kmem_cache *dentry_cache __read_mostly;


const struct qstr empty_name = QSTR_INIT("", 0);
EXPORT_SYMBOL(empty_name);

const struct qstr slash_name = QSTR_INIT("/", 1);
EXPORT_SYMBOL(slash_name);

/*
 * This is the single most critical data structure when it comes
 * to the dcache: the hashtable for lookups. Somebody should try
 * to make this good - I've just made it work.
 *
 * This hash-function tries to avoid losing too many bits of hash
 * information, yet avoid using a prime hash-size or similar.
 */


static unsigned int d_hash_shift __read_mostly;


static struct hlist_bl_head *dentry_hashtable __read_mostly;


static inline struct hlist_bl_head *d_hash(unsigned int hash) { return dentry_hashtable + (hash >> d_hash_shift); }

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Nicholas Piggin1672.73%120.00%
Linus Torvalds313.64%360.00%
George Spelvin313.64%120.00%
Total22100.00%5100.00%

#define IN_LOOKUP_SHIFT 10 static struct hlist_bl_head in_lookup_hashtable[1 << IN_LOOKUP_SHIFT];
static inline struct hlist_bl_head *in_lookup_hash(const struct dentry *parent, unsigned int hash) { hash += (unsigned long) parent / L1_CACHE_BYTES; return in_lookup_hashtable + hash_32(hash, IN_LOOKUP_SHIFT); }

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Al Viro39100.00%1100.00%
Total39100.00%1100.00%

/* Statistics gathering. */ struct dentry_stat_t dentry_stat = { .age_limit = 45, }; static DEFINE_PER_CPU(long, nr_dentry); static DEFINE_PER_CPU(long, nr_dentry_unused); #if defined(CONFIG_SYSCTL) && defined(CONFIG_PROC_FS) /* * Here we resort to our own counters instead of using generic per-cpu counters * for consistency with what the vfs inode code does. We are expected to harvest * better code and performance by having our own specialized counters. * * Please note that the loop is done over all possible CPUs, not over all online * CPUs. The reason for this is that we don't want to play games with CPUs going * on and off. If one of them goes off, we will just keep their counters. * * glommer: See cffbc8a for details, and if you ever intend to change this, * please update all vfs counters to match. */
static long get_nr_dentry(void) { int i; long sum = 0; for_each_possible_cpu(i) sum += per_cpu(nr_dentry, i); return sum < 0 ? 0 : sum; }

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Nicholas Piggin3694.74%150.00%
Glauber de Oliveira Costa25.26%150.00%
Total38100.00%2100.00%


static long get_nr_dentry_unused(void) { int i; long sum = 0; for_each_possible_cpu(i) sum += per_cpu(nr_dentry_unused, i); return sum < 0 ? 0 : sum; }

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Dave Chinner38100.00%1100.00%
Total38100.00%1100.00%


int proc_nr_dentry(struct ctl_table *table, int write, void __user *buffer, size_t *lenp, loff_t *ppos) { dentry_stat.nr_dentry = get_nr_dentry(); dentry_stat.nr_unused = get_nr_dentry_unused(); return proc_doulongvec_minmax(table, write, buffer, lenp, ppos); }

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Christoph Hellwig4379.63%120.00%
Dave Chinner712.96%120.00%
Nicholas Piggin23.70%120.00%
Glauber de Oliveira Costa11.85%120.00%
Joe Perches11.85%120.00%
Total54100.00%5100.00%

#endif /* * Compare 2 name strings, return 0 if they match, otherwise non-zero. * The strings are both count bytes long, and count is non-zero. */ #ifdef CONFIG_DCACHE_WORD_ACCESS #include <asm/word-at-a-time.h> /* * NOTE! 'cs' and 'scount' come from a dentry, so it has a * aligned allocation for this particular component. We don't * strictly need the load_unaligned_zeropad() safety, but it * doesn't hurt either. * * In contrast, 'ct' and 'tcount' can be from a pathname, and do * need the careful unaligned handling. */
static inline int dentry_string_cmp(const unsigned char *cs, const unsigned char *ct, unsigned tcount) { unsigned long a,b,mask; for (;;) { a = read_word_at_a_time(cs); b = load_unaligned_zeropad(ct); if (tcount < sizeof(unsigned long)) break; if (unlikely(a != b)) return 1; cs += sizeof(unsigned long); ct += sizeof(unsigned long); tcount -= sizeof(unsigned long); if (!tcount) return 0; } mask = bytemask_from_count(tcount); return unlikely(!!((a ^ b) & mask)); }

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Linus Torvalds12395.35%571.43%
Andrey Ryabinin32.33%114.29%
Will Deacon32.33%114.29%
Total129100.00%7100.00%

#else
static inline int dentry_string_cmp(const unsigned char *cs, const unsigned char *ct, unsigned tcount) { do { if (*cs != *ct) return 1; cs++; ct++; tcount--; } while (tcount); return 0; }

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Linus Torvalds53100.00%4100.00%
Total53100.00%4100.00%

#endif
static inline int dentry_cmp(const struct dentry *dentry, const unsigned char *ct, unsigned tcount) { /* * Be careful about RCU walk racing with rename: * use 'READ_ONCE' to fetch the name pointer. * * NOTE! Even if a rename will mean that the length * was not loaded atomically, we don't care. The * RCU walk will check the sequence count eventually, * and catch it. And we won't overrun the buffer, * because we're reading the name pointer atomically, * and a dentry name is guaranteed to be properly * terminated with a NUL byte. * * End result: even if 'len' is wrong, we'll exit * early because the data cannot match (there can * be no NUL in the ct/tcount data) */ const unsigned char *cs = READ_ONCE(dentry->d_name.name); return dentry_string_cmp(cs, ct, tcount); }

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Linus Torvalds4491.67%250.00%
He Kuang24.17%125.00%
Will Deacon24.17%125.00%
Total48100.00%4100.00%

struct external_name { union { atomic_t count; struct rcu_head head; } u; unsigned char name[]; };
static inline struct external_name *external_name(struct dentry *dentry) { return container_of(dentry->d_name.name, struct external_name, name[0]); }

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Al Viro32100.00%1100.00%
Total32100.00%1100.00%


static void __d_free(struct rcu_head *head) { struct dentry *dentry = container_of(head, struct dentry, d_u.d_rcu); kmem_cache_free(dentry_cache, dentry); }

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Christoph Hellwig1954.29%133.33%
Eric Dumazet1131.43%133.33%
Al Viro514.29%133.33%
Total35100.00%3100.00%


static void __d_free_external_name(struct rcu_head *head) { struct external_name *name = container_of(head, struct external_name, u.head); mod_node_page_state(page_pgdat(virt_to_page(name)), NR_INDIRECTLY_RECLAIMABLE_BYTES, -ksize(name)); kfree(name); }

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Roman Gushchin52100.00%1100.00%
Total52100.00%1100.00%


static void __d_free_external(struct rcu_head *head) { struct dentry *dentry = container_of(head, struct dentry, d_u.d_rcu); __d_free_external_name(&external_name(dentry)->u.head); kmem_cache_free(dentry_cache, dentry); }

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Al Viro2960.42%133.33%
Eric Dumazet1327.08%133.33%
Roman Gushchin612.50%133.33%
Total48100.00%3100.00%


static inline int dname_external(const struct dentry *dentry) { return dentry->d_name.name != dentry->d_iname; }

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Al Viro24100.00%1100.00%
Total24100.00%1100.00%


void take_dentry_name_snapshot(struct name_snapshot *name, struct dentry *dentry) { spin_lock(&dentry->d_lock); if (unlikely(dname_external(dentry))) { struct external_name *p = external_name(dentry); atomic_inc(&p->u.count); spin_unlock(&dentry->d_lock); name->name = p->name; } else { memcpy(name->inline_name, dentry->d_iname, DNAME_INLINE_LEN); spin_unlock(&dentry->d_lock); name->name = name->inline_name; } }

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Al Viro103100.00%1100.00%
Total103100.00%1100.00%

EXPORT_SYMBOL(take_dentry_name_snapshot);
void release_dentry_name_snapshot(struct name_snapshot *name) { if (unlikely(name->name != name->inline_name)) { struct external_name *p; p = container_of(name->name, struct external_name, name[0]); if (unlikely(atomic_dec_and_test(&p->u.count))) call_rcu(&p->u.head, __d_free_external_name); } }

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Al Viro6993.24%150.00%
Roman Gushchin56.76%150.00%
Total74100.00%2100.00%

EXPORT_SYMBOL(release_dentry_name_snapshot);
static inline void __d_set_inode_and_type(struct dentry *dentry, struct inode *inode, unsigned type_flags) { unsigned flags; dentry->d_inode = inode; flags = READ_ONCE(dentry->d_flags); flags &= ~(DCACHE_ENTRY_TYPE | DCACHE_FALLTHRU); flags |= type_flags; WRITE_ONCE(dentry->d_flags, flags); }

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David Howells60100.00%1100.00%
Total60100.00%1100.00%


static inline void __d_clear_type_and_inode(struct dentry *dentry) { unsigned flags = READ_ONCE(dentry->d_flags); flags &= ~(DCACHE_ENTRY_TYPE | DCACHE_FALLTHRU); WRITE_ONCE(dentry->d_flags, flags); dentry->d_inode = NULL; }

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David Howells46100.00%1100.00%
Total46100.00%1100.00%


static void dentry_free(struct dentry *dentry) { WARN_ON(!hlist_unhashed(&dentry->d_u.d_alias)); if (unlikely(dname_external(dentry))) { struct external_name *p = external_name(dentry); if (likely(atomic_dec_and_test(&p->u.count))) { call_rcu(&dentry->d_u.d_rcu, __d_free_external); return; } } /* if dentry was never visible to RCU, immediate free is OK */ if (!(dentry->d_flags & DCACHE_RCUACCESS)) __d_free(&dentry->d_u.d_rcu); else call_rcu(&dentry->d_u.d_rcu, __d_free); }

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Al Viro112100.00%3100.00%
Total112100.00%3100.00%

/* * Release the dentry's inode, using the filesystem * d_iput() operation if defined. */
static void dentry_unlink_inode(struct dentry * dentry) __releases(dentry->d_lock) __releases(dentry->d_inode->i_lock) { struct inode *inode = dentry->d_inode; raw_write_seqcount_begin(&dentry->d_seq); __d_clear_type_and_inode(dentry); hlist_del_init(&dentry->d_u.d_alias); raw_write_seqcount_end(&dentry->d_seq); spin_unlock(&dentry->d_lock); spin_unlock(&inode->i_lock); if (!inode->i_nlink) fsnotify_inoderemove(inode); if (dentry->d_op && dentry->d_op->d_iput) dentry->d_op->d_iput(dentry, inode); else iput(inode); }

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PersonTokensPropCommitsCommitProp
Nicholas Piggin7561.48%327.27%
Linus Torvalds (pre-git)1814.75%19.09%
Al Viro1613.11%436.36%
Miklos Szeredi86.56%19.09%
David Howells54.10%218.18%
Total122100.00%11100.00%

/* * The DCACHE_LRU_LIST bit is set whenever the 'd_lru' entry * is in use - which includes both the "real" per-superblock * LRU list _and_ the DCACHE_SHRINK_LIST use. * * The DCACHE_SHRINK_LIST bit is set whenever the dentry is * on the shrink list (ie not on the superblock LRU list). * * The per-cpu "nr_dentry_unused" counters are updated with * the DCACHE_LRU_LIST bit. * * These helper functions make sure we always follow the * rules. d_lock must be held by the caller. */ #define D_FLAG_VERIFY(dentry,x) WARN_ON_ONCE(((dentry)->d_flags & (DCACHE_LRU_LIST | DCACHE_SHRINK_LIST)) != (x))
static void d_lru_add(struct dentry *dentry) { D_FLAG_VERIFY(dentry, 0); dentry->d_flags |= DCACHE_LRU_LIST; this_cpu_inc(nr_dentry_unused); WARN_ON_ONCE(!list_lru_add(&dentry->d_sb->s_dentry_lru, &dentry->d_lru)); }

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Linus Torvalds2143.75%233.33%
Kentaro Makita2041.67%116.67%
Nicholas Piggin510.42%116.67%
Christoph Hellwig12.08%116.67%
Dave Chinner12.08%116.67%
Total48100.00%6100.00%


static void d_lru_del(struct dentry *dentry) { D_FLAG_VERIFY(dentry, DCACHE_LRU_LIST); dentry->d_flags &= ~DCACHE_LRU_LIST; this_cpu_dec(nr_dentry_unused); WARN_ON_ONCE(!list_lru_del(&dentry->d_sb->s_dentry_lru, &dentry->d_lru)); }

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Linus Torvalds4183.67%233.33%
Nicholas Piggin48.16%116.67%
Dave Chinner24.08%116.67%
Christoph Hellwig12.04%116.67%
Miklos Szeredi12.04%116.67%
Total49100.00%6100.00%


static void d_shrink_del(struct dentry *dentry) { D_FLAG_VERIFY(dentry, DCACHE_SHRINK_LIST | DCACHE_LRU_LIST); list_del_init(&dentry->d_lru); dentry->d_flags &= ~(DCACHE_SHRINK_LIST | DCACHE_LRU_LIST); this_cpu_dec(nr_dentry_unused); }

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Linus Torvalds2147.73%250.00%
Kentaro Makita1636.36%125.00%
Dave Chinner715.91%125.00%
Total44100.00%4100.00%


static void d_shrink_add(struct dentry *dentry, struct list_head *list) { D_FLAG_VERIFY(dentry, 0); list_add(&dentry->d_lru, list); dentry->d_flags |= DCACHE_SHRINK_LIST | DCACHE_LRU_LIST; this_cpu_inc(nr_dentry_unused); }

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Linus Torvalds4189.13%150.00%
Kentaro Makita510.87%150.00%
Total46100.00%2100.00%

/* * These can only be called under the global LRU lock, ie during the * callback for freeing the LRU list. "isolate" removes it from the * LRU lists entirely, while shrink_move moves it to the indicated * private list. */
static void d_lru_isolate(struct list_lru_one *lru, struct dentry *dentry) { D_FLAG_VERIFY(dentry, DCACHE_LRU_LIST); dentry->d_flags &= ~DCACHE_LRU_LIST; this_cpu_dec(nr_dentry_unused); list_lru_isolate(lru, &dentry->d_lru); }

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Linus Torvalds3168.89%133.33%
Vladimir Davydov817.78%133.33%
Christoph Hellwig613.33%133.33%
Total45100.00%3100.00%


static void d_lru_shrink_move(struct list_lru_one *lru, struct dentry *dentry, struct list_head *list) { D_FLAG_VERIFY(dentry, DCACHE_LRU_LIST); dentry->d_flags |= DCACHE_SHRINK_LIST; list_lru_isolate_move(lru, &dentry->d_lru, list); }

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Linus Torvalds3882.61%150.00%
Vladimir Davydov817.39%150.00%
Total46100.00%2100.00%

/** * d_drop - drop a dentry * @dentry: dentry to drop * * d_drop() unhashes the entry from the parent dentry hashes, so that it won't * be found through a VFS lookup any more. Note that this is different from * deleting the dentry - d_delete will try to mark the dentry negative if * possible, giving a successful _negative_ lookup, while d_drop will * just make the cache lookup fail. * * d_drop() is used mainly for stuff that wants to invalidate a dentry for some * reason (NFS timeouts or autofs deletes). * * __d_drop requires dentry->d_lock * ___d_drop doesn't mark dentry as "unhashed" * (dentry->d_hash.pprev will be LIST_POISON2, not NULL). */
static void ___d_drop(struct dentry *dentry) { struct hlist_bl_head *b; /* * Hashed dentries are normally on the dentry hashtable, * with the exception of those newly allocated by * d_obtain_root, which are always IS_ROOT: */ if (unlikely(IS_ROOT(dentry))) b = &dentry->d_sb->s_roots; else b = d_hash(dentry->d_name.hash); hlist_bl_lock(b); __hlist_bl_del(&dentry->d_hash); hlist_bl_unlock(b); }

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Nicholas Piggin4872.73%222.22%
Linus Torvalds913.64%222.22%
Neil Brown34.55%222.22%
J. Bruce Fields34.55%111.11%
Christoph Hellwig23.03%111.11%
Al Viro11.52%111.11%
Total66100.00%9100.00%


void __d_drop(struct dentry *dentry) { if (!d_unhashed(dentry)) { ___d_drop(dentry); dentry->d_hash.pprev = NULL; write_seqcount_invalidate(&dentry->d_seq); } }

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Neil Brown2356.10%150.00%
Al Viro1843.90%150.00%
Total41100.00%2100.00%

EXPORT_SYMBOL(__d_drop);
void d_drop(struct dentry *dentry) { spin_lock(&dentry->d_lock); __d_drop(dentry); spin_unlock(&dentry->d_lock); }

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Nicholas Piggin31100.00%1100.00%
Total31100.00%1100.00%

EXPORT_SYMBOL(d_drop);
static inline void dentry_unlist(struct dentry *dentry, struct dentry *parent) { struct dentry *next; /* * Inform d_walk() and shrink_dentry_list() that we are no longer * attached to the dentry tree */ dentry->d_flags |= DCACHE_DENTRY_KILLED; if (unlikely(list_empty(&dentry->d_child))) return; __list_del_entry(&dentry->d_child); /* * Cursors can move around the list of children. While we'd been * a normal list member, it didn't matter - ->d_child.next would've * been updated. However, from now on it won't be and for the * things like d_walk() it might end up with a nasty surprise. * Normally d_walk() doesn't care about cursors moving around - * ->d_lock on parent prevents that and since a cursor has no children * of its own, we get through it without ever unlocking the parent. * There is one exception, though - if we ascend from a child that * gets killed as soon as we unlock it, the next sibling is found * using the value left in its ->d_child.next. And if _that_ * pointed to a cursor, and cursor got moved (e.g. by lseek()) * before d_walk() regains parent->d_lock, we'll end up skipping * everything the cursor had been moved past. * * Solution: make sure that the pointer left behind in ->d_child.next * points to something that won't be moving around. I.e. skip the * cursors. */ while (dentry->d_child.next != &parent->d_subdirs) { next = list_entry(dentry->d_child.next, struct dentry, d_child); if (likely(!(next->d_flags & DCACHE_DENTRY_CURSOR))) break; dentry->d_child.next = next->d_child.next; } }

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Al Viro110100.00%1100.00%
Total110100.00%1100.00%


static void __dentry_kill(struct dentry *dentry) { struct dentry *parent = NULL; bool can_free = true; if (!IS_ROOT(dentry)) parent = dentry->d_parent; /* * The dentry is now unrecoverably dead to the world. */ lockref_mark_dead(&dentry->d_lockref); /* * inform the fs via d_prune that this dentry is about to be * unhashed and destroyed. */ if (dentry->d_flags & DCACHE_OP_PRUNE) dentry->d_op->d_prune(dentry); if (dentry->d_flags & DCACHE_LRU_LIST) { if (!(dentry->d_flags & DCACHE_SHRINK_LIST)) d_lru_del(dentry); } /* if it was on the hash then remove it */ __d_drop(dentry); dentry_unlist(dentry, parent); if (parent) spin_unlock(&parent->d_lock); if (dentry->d_inode) dentry_unlink_inode(dentry); else spin_unlock(&dentry->d_lock); this_cpu_dec(nr_dentry); if (dentry->d_op && dentry->d_op->d_release) dentry->d_op->d_release(dentry); spin_lock(&dentry->d_lock); if (dentry->d_flags & DCACHE_SHRINK_LIST) { dentry->d_flags |= DCACHE_MAY_FREE; can_free = false; } spin_unlock(&dentry->d_lock); if (likely(can_free)) dentry_free(dentry); cond_resched(); }

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Al Viro14568.40%866.67%
Nicholas Piggin4320.28%18.33%
Zheng Yan188.49%18.33%
Linus Torvalds52.36%18.33%
Waiman Long10.47%18.33%
Total212100.00%12100.00%


static struct dentry *__lock_parent(struct dentry *dentry) { struct dentry *parent; rcu_read_lock(); spin_unlock(&dentry->d_lock); again: parent = READ_ONCE(dentry->d_parent); spin_lock(&parent->d_lock); /* * We can't blindly lock dentry until we are sure * that we won't violate the locking order. * Any changes of dentry->d_parent must have * been done with parent->d_lock held, so * spin_lock() above is enough of a barrier * for checking if it's still our child. */ if (unlikely(parent != dentry->d_parent)) { spin_unlock(&parent->d_lock); goto again; } rcu_read_unlock(); if (parent != dentry) spin_lock_nested(&dentry->d_lock, DENTRY_D_LOCK_NESTED); else parent = NULL; return parent; }

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Al Viro9696.00%466.67%
Linus Torvalds33.00%116.67%
Mark Rutland11.00%116.67%
Total100100.00%6100.00%


static inline struct dentry *lock_parent(struct dentry *dentry) { struct dentry *parent = dentry->d_parent; if (IS_ROOT(dentry)) return NULL; if (likely(spin_trylock(&parent->d_lock))) return parent; return __lock_parent(dentry); }

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Al Viro55100.00%1100.00%
Total55100.00%1100.00%


static inline bool retain_dentry(struct dentry *dentry) { WARN_ON(d_in_lookup(dentry)); /* Unreachable? Get rid of it */ if (unlikely(d_unhashed(dentry))) return false; if (unlikely(dentry->d_flags & DCACHE_DISCONNECTED)) return false; if (unlikely(dentry->d_flags & DCACHE_OP_DELETE)) { if (dentry->d_op->d_delete(dentry)) return false; } /* retain; LRU fodder */ dentry->d_lockref.count--; if (unlikely(!(dentry->d_flags & DCACHE_LRU_LIST))) d_lru_add(dentry); else if (unlikely(!(dentry->d_flags & DCACHE_REFERENCED))) dentry->d_flags |= DCACHE_REFERENCED; return true; }

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Al Viro126100.00%2100.00%
Total126100.00%2100.00%

/* * Finish off a dentry we've decided to kill. * dentry->d_lock must be held, returns with it unlocked. * Returns dentry requiring refcount drop, or NULL if we're done. */
static struct dentry *dentry_kill(struct dentry *dentry) __releases(dentry->d_lock) { struct inode *inode = dentry->d_inode; struct dentry *parent = NULL; if (inode && unlikely(!spin_trylock(&inode->i_lock))) goto slow_positive; if (!IS_ROOT(dentry)) { parent = dentry->d_parent; if (unlikely(!spin_trylock(&parent->d_lock))) { parent = __lock_parent(dentry); if (likely(inode || !dentry->d_inode)) goto got_locks; /* negative that became positive */ if (parent) spin_unlock(&parent->d_lock); inode = dentry->d_inode; goto slow_positive; } } __dentry_kill(dentry); return parent; slow_positive: spin_unlock(&dentry->d_lock); spin_lock(&inode->i_lock); spin_lock(&dentry->d_lock); parent = lock_parent(dentry); got_locks: if (unlikely(dentry->d_lockref.count != 1)) { dentry->d_lockref.count--; } else if (likely(!retain_dentry(dentry))) { __dentry_kill(dentry); return parent; } /* we are keeping it, after all */ if (inode) spin_unlock(&inode->i_lock); if (parent) spin_unlock(&parent->d_lock); spin_unlock(&dentry->d_lock); return NULL; }

Contributors

PersonTokensPropCommitsCommitProp
Al Viro13653.75%150.00%
John Ogness11746.25%150.00%
Total253100.00%2100.00%

/* * Try to do a lockless dput(), and return whether that was successful. * * If unsuccessful, we return false, having already taken the dentry lock. * * The caller needs to hold the RCU read lock, so that the dentry is * guaranteed to stay around even if the refcount goes down to zero! */
static inline bool fast_dput(struct dentry *dentry) { int ret; unsigned int d_flags; /* * If we have a d_op->d_delete() operation, we sould not * let the dentry count go to zero, so use "put_or_lock". */ if (unlikely(dentry->d_flags & DCACHE_OP_DELETE)) return lockref_put_or_lock(&dentry->d_lockref); /* * .. otherwise, we can try to just decrement the * lockref optimistically. */ ret = lockref_put_return(&dentry->d_lockref); /* * If the lockref_put_return() failed due to the lock being held * by somebody else, the fast path has failed. We will need to * get the lock, and then check the count again. */ if (unlikely(ret < 0)) { spin_lock(&dentry->d_lock); if (dentry->d_lockref.count > 1) { dentry->d_lockref.count--; spin_unlock(&dentry->d_lock); return 1; } return 0; } /* * If we weren't the last ref, we're done. */ if (ret) return 1; /* * Careful, careful. The reference count went down * to zero, but we don't hold the dentry lock, so * somebody else could get it again, and do another * dput(), and we need to not race with that. * * However, there is a very special and common case * where we don't care, because there is nothing to * do: the dentry is still hashed, it does not have * a 'delete' op, and it's referenced and already on * the LRU list. * * NOTE! Since we aren't locked, these values are * not "stable". However, it is sufficient that at * some point after we dropped the reference the * dentry was hashed and the flags had the proper * value. Other dentry users may have re-gotten * a reference to the dentry and change that, but * our work is done - we can leave the dentry * around with a zero refcount. */ smp_rmb(); d_flags = READ_ONCE(dentry->d_flags); d_flags &= DCACHE_REFERENCED | DCACHE_LRU_LIST | DCACHE_DISCONNECTED; /* Nothing to do? Dropping the reference was all we needed? */ if (d_flags == (DCACHE_REFERENCED | DCACHE_LRU_LIST) && !d_unhashed(dentry)) return 1; /* * Not the fast normal case? Get the lock. We've already decremented * the refcount, but we'll need to re-check the situation after * getting the lock. */ spin_lock(&dentry->d_lock); /* * Did somebody else grab a reference to it in the meantime, and * we're no longer the last user after all? Alternatively, somebody * else could have killed it and marked it dead. Either way, we * don't need to do anything else. */ if (dentry->d_lockref.count) { spin_unlock(&dentry->d_lock); return 1; } /* * Re-get the reference we optimistically dropped. We hold the * lock, and we just tested that it was zero, so we can just * set it to 1. */ dentry->d_lockref.count = 1; return 0; }

Contributors

PersonTokensPropCommitsCommitProp
Linus Torvalds19297.96%133.33%
Al Viro31.53%133.33%
Mark Rutland10.51%133.33%
Total196100.00%3100.00%

/* * This is dput * * This is complicated by the fact that we do not want to put * dentries that are no longer on any hash chain on the unused * list: we'd much rather just get rid of them immediately. * * However, that implies that we have to traverse the dentry * tree upwards to the parents which might _also_ now be * scheduled for deletion (it may have been only waiting for * its last child to go away). * * This tail recursion is done by hand as we don't want to depend * on the compiler to always get this right (gcc generally doesn't). * Real recursion would eat up our stack space. */ /* * dput - release a dentry * @dentry: dentry to release * * Release a dentry. This will drop the usage count and if appropriate * call the dentry unlink method as well as removing it from the queues and * releasing its resources. If the parent dentries were scheduled for release * they too may now get deleted. */
void dput(struct dentry *dentry) { while (dentry) { might_sleep(); rcu_read_lock(); if (likely(fast_dput(dentry))) { rcu_read_unlock(); return; } /* Slow case: now with the dentry lock held */ rcu_read_unlock(); if (likely(retain_dentry(dentry))) { spin_unlock(&dentry->d_lock); return; } dentry = dentry_kill(dentry); } }

Contributors

PersonTokensPropCommitsCommitProp
Linus Torvalds (pre-git)2231.43%945.00%
Linus Torvalds2130.00%210.00%
Andrew Morton1115.71%15.00%
Al Viro57.14%210.00%
Wei Fang45.71%15.00%
Nicholas Piggin45.71%315.00%
Ingo Molnar22.86%15.00%
Waiman Long11.43%15.00%
Total70100.00%20100.00%

EXPORT_SYMBOL(dput); /* This must be called with d_lock held */
static inline void __dget_dlock(struct dentry *dentry) { dentry->d_lockref.count++; }

Contributors

PersonTokensPropCommitsCommitProp
Nicholas Piggin1684.21%375.00%
Waiman Long315.79%125.00%
Total19100.00%4100.00%


static inline void __dget(struct dentry *dentry) { lockref_get(&dentry->d_lockref); }

Contributors

PersonTokensPropCommitsCommitProp
Linus Torvalds (pre-git)945.00%120.00%
Nicholas Piggin945.00%360.00%
Waiman Long210.00%120.00%
Total20100.00%5100.00%


struct dentry *dget_parent(struct dentry *dentry) { int gotref; struct dentry *ret; /* * Do optimistic parent lookup without any * locking. */ rcu_read_lock(); ret = READ_ONCE(dentry->d_parent); gotref = lockref_get_not_zero(&ret->d_lockref); rcu_read_unlock(); if (likely(gotref)) { if (likely(ret == READ_ONCE(dentry->d_parent))) return ret; dput(ret); } repeat: /* * Don't need rcu_dereference because we re-check it was correct under * the lock. */ rcu_read_lock(); ret = dentry->d_parent; spin_lock(&ret->d_lock); if (unlikely(ret != dentry->d_parent)) { spin_unlock(&ret->d_lock); rcu_read_unlock(); goto repeat; } rcu_read_unlock(); BUG_ON(!ret->d_lockref.count); ret->d_lockref.count++; spin_unlock(&ret->d_lock); return ret; }

Contributors

PersonTokensPropCommitsCommitProp
Nicholas Piggin8957.42%240.00%
Waiman Long6441.29%240.00%
Mark Rutland21.29%120.00%
Total155100.00%5100.00%

EXPORT_SYMBOL(dget_parent);
static struct dentry * __d_find_any_alias(struct inode *inode) { struct dentry *alias; if (hlist_empty(&inode->i_dentry)) return NULL; alias = hlist_entry(inode->i_dentry.first, struct dentry, d_u.d_alias); __dget(alias); return alias; }

Contributors

PersonTokensPropCommitsCommitProp
Al Viro3052.63%120.00%
Linus Torvalds (pre-git)1933.33%120.00%
Neil Brown58.77%240.00%
Nicholas Piggin35.26%120.00%
Total57100.00%5100.00%

/** * d_find_any_alias - find any alias for a given inode * @inode: inode to find an alias for * * If any aliases exist for the given inode, take and return a * reference for one of them. If no aliases exist, return %NULL. */
struct dentry *d_find_any_alias(struct inode *inode) { struct dentry *de; spin_lock(&inode->i_lock); de = __d_find_any_alias(inode); spin_unlock(&inode->i_lock); return de; }

Contributors

PersonTokensPropCommitsCommitProp
Al Viro2762.79%116.67%
Linus Torvalds (pre-git)716.28%233.33%
Nicholas Piggin613.95%116.67%
Neil Brown36.98%233.33%
Total43100.00%6100.00%

EXPORT_SYMBOL(d_find_any_alias); /** * d_find_alias - grab a hashed alias of inode * @inode: inode in question * * If inode has a hashed alias, or is a directory and has any alias, * acquire the reference to alias and return it. Otherwise return NULL. * Notice that if inode is a directory there can be only one alias and * it can be unhashed only if it has no children, or if it is the root * of a filesystem, or if the directory was renamed and d_revalidate * was the first vfs operation to notice. * * If the inode has an IS_ROOT, DCACHE_DISCONNECTED alias, then prefer * any other hashed alias over that one. */
static struct dentry *__d_find_alias(struct inode *inode) { struct dentry *alias; if (S_ISDIR(inode->i_mode)) return __d_find_any_alias(inode); hlist_for_each_entry(alias, &inode->i_dentry, d_u.d_alias) { spin_lock(&alias->d_lock); if (!d_unhashed(alias)) { __dget_dlock(alias); spin_unlock(&alias->d_lock); return alias; } spin_unlock(&alias->d_lock); } return NULL; }

Contributors

PersonTokensPropCommitsCommitProp
Nicholas Piggin4348.86%240.00%
Al Viro3742.05%120.00%
Neil Brown89.09%240.00%
Total88100.00%5100.00%


struct dentry *d_find_alias(struct inode *inode) { struct dentry *de = NULL; if (!hlist_empty(&inode->i_dentry)) { spin_lock(&inode->i_lock); de = __d_find_alias(inode); spin_unlock(&inode->i_lock); } return de; }

Contributors

PersonTokensPropCommitsCommitProp
Neil Brown2746.55%114.29%
David Howells1424.14%114.29%
Nicholas Piggin1017.24%228.57%
Linus Torvalds (pre-git)610.34%228.57%
Al Viro11.72%114.29%
Total58100.00%7100.00%

EXPORT_SYMBOL(d_find_alias); /* * Try to kill dentries associated with this inode. * WARNING: you must own a reference to inode. */
void d_prune_aliases(struct inode *inode) { struct dentry *dentry; restart: spin_lock(&inode->i_lock); hlist_for_each_entry(dentry, &inode->i_dentry, d_u.d_alias) { spin_lock(&dentry->d_lock); if (!dentry->d_lockref.count) { struct dentry *parent = lock_parent(dentry); if (likely(!dentry->d_lockref.count)) { __dentry_kill(dentry); dput(parent); goto restart; } if (parent) spin_unlock(&parent->d_lock); } spin_unlock(&dentry->d_lock); } spin_unlock(&inode->i_lock); }

Contributors

PersonTokensPropCommitsCommitProp
Linus Torvalds (pre-git)4134.45%215.38%
Al Viro2823.53%323.08%
Jan Blunck2016.81%17.69%
Nicholas Piggin108.40%215.38%
Domen Puncer54.20%17.69%
Yan, Zheng54.20%17.69%
Zheng Yan43.36%17.69%
Andrew Morton32.52%17.69%
Waiman Long32.52%17.69%
Total119100.00%13100.00%

EXPORT_SYMBOL(d_prune_aliases); /* * Lock a dentry from shrink list. * Called under rcu_read_lock() and dentry->d_lock; the former * guarantees that nothing we access will be freed under us. * Note that dentry is *not* protected from concurrent dentry_kill(), * d_delete(), etc. * * Return false if dentry has been disrupted or grabbed, leaving * the caller to kick it off-list. Otherwise, return true and have * that dentry's inode and parent both locked. */
static bool shrink_lock_dentry(struct dentry *dentry) { struct inode *inode; struct dentry *parent; if (dentry->d_lockref.count) return false; inode = dentry->d_inode; if (inode && unlikely(!spin_trylock(&inode->i_lock))) { spin_unlock(&dentry->d_lock); spin_lock(&inode->i_lock); spin_lock(&dentry->d_lock); if (unlikely(dentry->d_lockref.count)) goto out; /* changed inode means that somebody had grabbed it */ if (unlikely(inode != dentry->d_inode)) goto out; } parent = dentry->d_parent; if (IS_ROOT(dentry) || likely(spin_trylock(&parent->d_lock))) return true; spin_unlock(&dentry->d_lock); spin_lock(&parent->d_lock); if (unlikely(parent != dentry->d_parent)) { spin_unlock(&parent->d_lock); spin_lock(&dentry->d_lock); goto out; } spin_lock_nested(&dentry->d_lock, DENTRY_D_LOCK_NESTED); if (likely(!dentry->d_lockref.count)) return true; spin_unlock(&parent->d_lock); out: if (inode) spin_unlock(&inode->i_lock); return false; }

Contributors

PersonTokensPropCommitsCommitProp
Al Viro19482.91%545.45%
Christoph Hellwig208.55%19.09%
Nicholas Piggin114.70%218.18%
Dave Chinner41.71%19.09%
Waiman Long31.28%19.09%
Miklos Szeredi20.85%19.09%
Total234100.00%11100.00%


static void shrink_dentry_list(struct list_head *list) { while (!list_empty(list)) { struct dentry *dentry, *parent; dentry = list_entry(list->prev, struct dentry, d_lru); spin_lock(&dentry->d_lock); rcu_read_lock(); if (!shrink_lock_dentry(dentry)) { bool can_free = false; rcu_read_unlock(); d_shrink_del(dentry); if (dentry->d_lockref.count < 0) can_free = dentry->d_flags & DCACHE_MAY_FREE; spin_unlock(&dentry->d_lock); if (can_free) dentry_free(dentry); continue; } rcu_read_unlock(); d_shrink_del(dentry); parent = dentry->d_parent; __dentry_kill(dentry); if (parent == dentry) continue; /* * We need to prune ancestors too. This is necessary to prevent * quadratic behavior of shrink_dcache_parent(), but is also * expected to be beneficial in reducing dentry cache * fragmentation. */ dentry = parent; while (dentry && !lockref_put_or_lock(&dentry->d_lockref)) dentry = dentry_kill(dentry); } }

Contributors

PersonTokensPropCommitsCommitProp
Al Viro13984.76%450.00%
John Ogness106.10%112.50%
Dave Chinner95.49%112.50%
Nicholas Piggin53.05%112.50%
Christoph Hellwig10.61%112.50%
Total164100.00%8100.00%


static enum lru_status dentry_lru_isolate(struct list_head *item, struct list_lru_one *lru, spinlock_t *lru_lock, void *arg) { struct list_head *freeable = arg; struct dentry *dentry = container_of(item, struct dentry, d_lru); /* * we are inverting the lru lock/dentry->d_lock here, * so use a trylock. If we fail to get the lock, just skip * it */ if (!spin_trylock(&dentry->d_lock)) return LRU_SKIP; /* * Referenced dentries are still in use. If they have active * counts, just remove them from the LRU. Otherwise give them * another pass through the LRU. */ if (dentry->d_lockref.count) { d_lru_isolate(lru, dentry); spin_unlock(&dentry->d_lock); return LRU_REMOVED; } if (dentry->d_flags & DCACHE_REFERENCED) { dentry->d_flags &= ~DCACHE_REFERENCED; spin_unlock(&dentry->d_lock); /* * The list move itself will be made by the common LRU code. At * this point, we've dropped the dentry->d_lock but keep the * lru lock. This is safe to do, since every list movement is * protected by the lru lock even if both locks are held. * * This is guaranteed by the fact that all LRU management * functions are intermediated by the LRU API calls like * list_lru_add and list_lru_del. List movement in this file * only ever occur through this functions or through callbacks * like this one, that are called from the LRU API. * * The only exceptions to this are functions like * shrink_dentry_list, and code that first checks for the * DCACHE_SHRINK_LIST flag. Those are guaranteed to be * operating only with stack provided lists after they are * properly isolated from the main list. It is thus, always a * local access. */ return LRU_ROTATE; } d_lru_shrink_move(lru, dentry, freeable); spin_unlock(&dentry->d_lock); return LRU_REMOVED; }

Contributors

PersonTokensPropCommitsCommitProp
Dave Chinner5640.00%214.29%
Kentaro Makita3021.43%17.14%
Neil Brown139.29%17.14%
Nicholas Piggin128.57%17.14%
Vladimir Davydov96.43%17.14%
Christoph Hellwig75.00%17.14%
Linus Torvalds (pre-git)64.29%428.57%
Andi Kleen32.14%17.14%
Linus Torvalds21.43%17.14%
Andrew Morton21.43%17.14%
Total140100.00%14100.00%

/** * prune_dcache_sb - shrink the dcache * @sb: superblock * @sc: shrink control, passed to list_lru_shrink_walk() * * Attempt to shrink the superblock dcache LRU by @sc->nr_to_scan entries. This * is done when we need more memory and called from the superblock shrinker * function. * * This function may fail to free any resources if all the dentries are in * use. */
long prune_dcache_sb(struct super_block *sb, struct shrink_control *sc) { LIST_HEAD(dispose); long freed; freed = list_lru_shrink_walk(&sb->s_dentry_lru, sc, dentry_lru_isolate, &dispose); shrink_dentry_list(&dispose); return freed; }

Contributors

PersonTokensPropCommitsCommitProp
Dave Chinner2755.10%440.00%
Nicholas Piggin612.24%220.00%
Vladimir Davydov612.24%110.00%
Kentaro Makita510.20%110.00%
Christoph Hellwig48.16%110.00%
Linus Torvalds (pre-git)12.04%110.00%
Total49100.00%10100.00%


static enum lru_status dentry_lru_isolate_shrink(struct list_head *item, struct list_lru_one *lru, spinlock_t *lru_lock, void *arg) { struct list_head *freeable = arg; struct dentry *dentry = container_of(item, struct dentry, d_lru); /* * we are inverting the lru lock/dentry->d_lock here, * so use a trylock. If we fail to get the lock, just skip * it */ if (!spin_trylock(&dentry->d_lock)) return LRU_SKIP; d_lru_shrink_move(lru, dentry, freeable); spin_unlock(&dentry->d_lock); return LRU_REMOVED; }

Contributors

PersonTokensPropCommitsCommitProp
Glauber de Oliveira Costa4048.78%114.29%
Dave Chinner1923.17%114.29%
Kentaro Makita78.54%114.29%
Vladimir Davydov78.54%114.29%
Nicholas Piggin44.88%114.29%
Linus Torvalds (pre-git)44.88%114.29%
Linus Torvalds11.22%114.29%
Total82100.00%7100.00%

/** * shrink_dcache_sb - shrink dcache for a superblock * @sb: superblock * * Shrink the dcache for the specified super block. This is used to free * the dcache before unmounting a file system. */
void shrink_dcache_sb(struct super_block *sb) { long freed; do { LIST_HEAD(dispose); freed = list_lru_walk(&sb->s_dentry_lru, dentry_lru_isolate_shrink, &dispose, 1024); this_cpu_sub(nr_dentry_unused, freed); shrink_dentry_list(&dispose); } while (list_lru_count(&sb->s_dentry_lru) > 0); }

Contributors

PersonTokensPropCommitsCommitProp
Glauber de Oliveira Costa1828.12%110.00%
Christoph Hellwig1320.31%110.00%
Kentaro Makita1015.62%110.00%
Sahitya Tummala812.50%110.00%
Nicholas Piggin710.94%220.00%
Dave Chinner69.38%220.00%
Linus Torvalds (pre-git)23.12%220.00%
Total64100.00%10100.00%

EXPORT_SYMBOL(shrink_dcache_sb); /** * enum d_walk_ret - action to talke during tree walk * @D_WALK_CONTINUE: contrinue walk * @D_WALK_QUIT: quit walk * @D_WALK_NORETRY: quit when retry is needed * @D_WALK_SKIP: skip this dentry and its children */ enum d_walk_ret { D_WALK_CONTINUE, D_WALK_QUIT, D_WALK_NORETRY, D_WALK_SKIP, }; /** * d_walk - walk the dentry tree * @parent: start of walk * @data: data passed to @enter() and @finish() * @enter: callback when first entering the dentry * * The @enter() callbacks are called with d_lock held. */ static void d_walk(struct dentry *parent, void *data, enum d_walk_ret (*enter)(void *, struct dentry *)) { struct dentry *this_parent; struct list_head *next; unsigned seq = 0; enum d_walk_ret ret; bool retry = true; again: read_seqbegin_or_lock(&rename_lock, &seq); this_parent = parent; spin_lock(&this_parent->d_lock); ret = enter(data, this_parent); switch (ret) { case D_WALK_CONTINUE: break; case D_WALK_QUIT: case D_WALK_SKIP: goto out_unlock; case D_WALK_NORETRY: retry = false; break; } repeat: next = this_parent->d_subdirs.next; resume: while (next != &this_parent->d_subdirs) { struct list_head *tmp = next; struct dentry *dentry = list_entry(tmp, struct dentry, d_child); next = tmp->next; if (unlikely(dentry->d_flags & DCACHE_DENTRY_CURSOR)) continue; spin_lock_nested(&dentry->d_lock, DENTRY_D_LOCK_NESTED); ret = enter(data, dentry); switch (ret) { case D_WALK_CONTINUE: break; case D_WALK_QUIT: spin_unlock(&dentry->d_lock); goto out_unlock; case D_WALK_NORETRY: retry = false; break; case D_WALK_SKIP: spin_unlock(&dentry->d_lock); continue; } if (!list_empty(&dentry->d_subdirs)) { spin_unlock(&this_parent->d_lock); spin_release(&dentry->d_lock.dep_map, 1, _RET_IP_); this_parent = dentry; spin_acquire(&this_parent->d_lock.dep_map, 0, 1, _RET_IP_); goto repeat; } spin_unlock(&dentry->d_lock); } /* * All done at this level ... ascend and resume the search. */ rcu_read_lock(); ascend: if (this_parent != parent) { struct dentry *child = this_parent; this_parent = child->d_parent; spin_unlock(&child->d_lock); spin_lock(&this_parent->d_lock); /* might go back up the wrong parent if we have had a rename. */ if (need_seqretry(&rename_lock, seq)) goto rename_retry; /* go into the first sibling still alive */ do { next = child->d_child.next; if (next == &this_parent->d_subdirs) goto ascend; child = list_entry(next, struct dentry, d_child); } while (unlikely(child->d_flags & DCACHE_DENTRY_KILLED)); rcu_read_unlock(); goto resume; } if (need_seqretry(&rename_lock, seq)) goto rename_retry; rcu_read_unlock(); out_unlock: spin_unlock(&this_parent->d_lock); done_seqretry(&rename_lock, seq); return; rename_retry: spin_unlock(&this_parent->d_lock); rcu_read_unlock(); BUG_ON(seq & 1); if (!retry) return; seq = 1; goto again; } struct check_mount { struct vfsmount *mnt; unsigned int mounted; };
static enum d_walk_ret path_check_mount(void *data, struct dentry *dentry) { struct check_mount *info = data; struct path path = { .mnt = info->mnt, .dentry = dentry }; if (likely(!d_mountpoint(dentry))) return D_WALK_CONTINUE; if (__path_is_mountpoint(&path)) { info->mounted = 1; return D_WALK_QUIT; } return D_WALK_CONTINUE; }

Contributors

PersonTokensPropCommitsCommitProp
Ian Kent77100.00%1100.00%
Total77100.00%1100.00%

/** * path_has_submounts - check for mounts over a dentry in the * current namespace. * @parent: path to check. * * Return true if the parent or its subdirectories contain * a mount point in the current namespace. */
int path_has_submounts(const struct path *parent) { struct check_mount data = { .mnt = parent->mnt, .mounted = 0 }; read_seqlock_excl(&mount_lock); d_walk(parent->dentry, &data, path_check_mount); read_sequnlock_excl(&mount_lock); return data.mounted; }

Contributors

PersonTokensPropCommitsCommitProp
Ian Kent58100.00%1100.00%
Total58100.00%1100.00%

EXPORT_SYMBOL(path_has_submounts); /* * Called by mount code to set a mountpoint and check if the mountpoint is * reachable (e.g. NFS can unhash a directory dentry and then the complete * subtree can become unreachable). * * Only one of d_invalidate() and d_set_mounted() must succeed. For * this reason take rename_lock and d_lock on dentry and ancestors. */
int d_set_mounted(struct dentry *dentry) { struct dentry *p; int ret = -ENOENT; write_seqlock(&rename_lock); for (p = dentry->d_parent; !IS_ROOT(p); p = p->d_parent) { /* Need exclusion wrt. d_invalidate() */ spin_lock(&p->d_lock); if (unlikely(d_unhashed(p))) { spin_unlock(&p->d_lock); goto out; } spin_unlock(&p->d_lock); } spin_lock(&dentry->d_lock); if (!d_unlinked(dentry)) { ret = -EBUSY; if (!d_mountpoint(dentry)) { dentry->d_flags |= DCACHE_MOUNTED; ret = 0; } } spin_unlock(&dentry->d_lock); out: write_sequnlock(&rename_lock); return ret; }

Contributors

PersonTokensPropCommitsCommitProp
Miklos Szeredi13589.40%133.33%
Eric W. Biedermann1610.60%266.67%
Total151100.00%3100.00%

/* * Search the dentry child list of the specified parent, * and move any unused dentries to the end of the unused * list for prune_dcache(). We descend to the next level * whenever the d_subdirs list is non-empty and continue * searching. * * It returns zero iff there are no unused children, * otherwise it returns the number of children moved to * the end of the unused list. This may not be the total * number of unused children, because select_parent can * drop the lock and return early due to latency * constraints. */ struct select_data { struct dentry *start; struct list_head dispose; int found; };
static enum d_walk_ret select_collect(void *_data, struct dentry *dentry) { struct select_data *data = _data; enum d_walk_ret ret = D_WALK_CONTINUE; if (data->start == dentry) goto out; if (dentry->d_flags & DCACHE_SHRINK_LIST) { data->found++; } else { if (dentry->d_flags & DCACHE_LRU_LIST) d_lru_del(dentry); if (!dentry->d_lockref.count) { d_shrink_add(dentry, &data->dispose); data->found++; } } /* * We can return to the caller if we have found some (this * ensures forward progress). We'll be coming back to find * the rest. */ if (!list_empty(&data->dispose)) ret = need_resched() ? D_WALK_QUIT : D_WALK_NORETRY; out: return ret; }

Contributors

PersonTokensPropCommitsCommitProp
Al Viro123100.00%2100.00%
Total123100.00%2100.00%

/** * shrink_dcache_parent - prune dcache * @parent: parent of entries to prune * * Prune the dcache to remove unused children of the parent dentry. */
void shrink_dcache_parent(struct dentry *parent) { for (;;) { struct select_data data; INIT_LIST_HEAD(&data.dispose); data.start = parent; data.found = 0; d_walk(parent, &data, select_collect); if (!list_empty(&data.dispose)) { shrink_dentry_list(&data.dispose); continue; } cond_resched(); if (!data.found) break; } }

Contributors

PersonTokensPropCommitsCommitProp
Al Viro8196.43%266.67%
Miklos Szeredi33.57%133.33%
Total84100.00%3100.00%

EXPORT_SYMBOL(shrink_dcache_parent);
static enum d_walk_ret umount_check(void *_data, struct dentry *dentry) { /* it has busy descendents; complain about those instead */ if (!list_empty(&dentry->d_subdirs)) return D_WALK_CONTINUE; /* root with refcount 1 is fine */ if (dentry == _data && dentry->d_lockref.count == 1) return D_WALK_CONTINUE; printk(KERN_ERR "BUG: Dentry %p{i=%lx,n=%pd} " " still in use (%d) [unmount of %s %s]\n", dentry, dentry->d_inode ? dentry->d_inode->i_ino : 0UL, dentry, dentry->d_lockref.count, dentry->d_sb->s_type->name, dentry->d_sb->s_id); WARN_ON(1); return D_WALK_CONTINUE; }

Contributors

PersonTokensPropCommitsCommitProp
Al Viro7171.00%233.33%
Linus Torvalds (pre-git)1414.00%116.67%
Miklos Szeredi1111.00%116.67%
Waiman Long33.00%116.67%
Nicholas Piggin11.00%116.67%
Total100100.00%6100.00%


static void do_one_tree(struct dentry *dentry) { shrink_dcache_parent(dentry); d_walk(dentry, dentry, umount_check); d_drop(dentry); dput(dentry); }

Contributors

PersonTokensPropCommitsCommitProp
Al Viro2262.86%228.57%
Dave Chinner411.43%114.29%
Christoph Hellwig411.43%114.29%
Miklos Szeredi38.57%228.57%
Nicholas Piggin25.71%114.29%
Total35100.00%7100.00%

/* * destroy the dentries attached to a superblock on unmounting */
void shrink_dcache_for_umount(struct super_block *sb) { struct dentry *dentry; WARN(down_read_trylock(&sb->s_umount), "s_umount should've been locked"); dentry = sb->s_root; sb->s_root = NULL; do_one_tree(dentry); while (!hlist_bl_empty(&sb->s_roots)) { dentry = dget(hlist_bl_entry(hlist_bl_first(&sb->s_roots), struct dentry, d_hash)); do_one_tree(dentry); } }

Contributors

PersonTokensPropCommitsCommitProp
Al Viro6880.95%233.33%
Miklos Szeredi78.33%116.67%
Nicholas Piggin67.14%116.67%
Neil Brown22.38%116.67%
Linus Torvalds (pre-git)11.19%116.67%
Total84100.00%6100.00%


static enum d_walk_ret find_submount(void *_data, struct dentry *dentry) { struct dentry **victim = _data; if (d_mountpoint(dentry)) { __dget_dlock(dentry); *victim = dentry; return D_WALK_QUIT; } return D_WALK_CONTINUE; }

Contributors

PersonTokensPropCommitsCommitProp
Miklos Szeredi3673.47%133.33%
Al Viro714.29%133.33%
Eric W. Biedermann612.24%133.33%
Total49100.00%3100.00%

/** * d_invalidate - detach submounts, prune dcache, and drop * @dentry: dentry to invalidate (aka detach, prune and drop) */
void d_invalidate(struct dentry *dentry) { bool had_submounts = false; spin_lock(&dentry->d_lock); if (d_unhashed(dentry)) { spin_unlock(&dentry->d_lock); return; } __d_drop(dentry); spin_unlock(&dentry->d_lock); /* Negative dentries can be dropped without further checks */ if (!dentry->d_inode) return; shrink_dcache_parent(dentry); for (;;) { struct dentry *victim = NULL; d_walk(dentry, &victim, find_submount); if (!victim) { if (had_submounts) shrink_dcache_parent(dentry); return; } had_submounts = true; detach_mounts(victim); dput(victim); } }

Contributors

PersonTokensPropCommitsCommitProp
Eric W. Biedermann4536.59%350.00%
Miklos Szeredi3931.71%116.67%
Al Viro3931.71%233.33%
Total123100.00%6100.00%

EXPORT_SYMBOL(d_invalidate); /** * __d_alloc - allocate a dcache entry * @sb: filesystem it will belong to * @name: qstr of the name * * Allocates a dentry. It returns %NULL if there is insufficient memory * available. On a success the dentry is returned. The name passed in is * copied and the copy passed in may be reused after this call. */
struct dentry *__d_alloc(struct super_block *sb, const struct qstr *name) { struct external_name *ext = NULL; struct dentry *dentry; char *dname; int err; dentry = kmem_cache_alloc(dentry_cache, GFP_KERNEL); if (!dentry) return NULL; /* * We guarantee that the inline name is always NUL-terminated. * This way the memcpy() done by the name switching in rename * will still always have a NUL at the end, even if we might * be overwriting an internal NUL character */ dentry->d_iname[DNAME_INLINE_LEN-1] = 0; if (unlikely(!name)) { name = &slash_name; dname = dentry->d_iname; } else if (name->len > DNAME_INLINE_LEN-1) { size_t size = offsetof(struct external_name, name[1]); ext = kmalloc(size + name->len, GFP_KERNEL_ACCOUNT); if (!ext) { kmem_cache_free(dentry_cache, dentry); return NULL; } atomic_set(&ext->u.count, 1); dname = ext->name; } else { dname = dentry->d_iname; } dentry->d_name.len = name->len; dentry->d_name.hash = name->hash; memcpy(dname, name->name, name->len); dname[name->len] = 0; /* Make sure we always see the terminating NUL character */ smp_store_release(&dentry->d_name.name, dname); /* ^^^ */ dentry->d_lockref.count = 1; dentry->d_flags = 0; spin_lock_init(&dentry->d_lock); seqcount_init(&dentry->d_seq); dentry->d_inode = NULL; dentry->d_parent = dentry; dentry->d_sb = sb; dentry->d_op = NULL; dentry->d_fsdata = NULL; INIT_HLIST_BL_NODE(&dentry->d_hash); INIT_LIST_HEAD(&dentry->d_lru); INIT_LIST_HEAD(&dentry->d_subdirs); INIT_HLIST_NODE(&dentry->d_u.d_alias); INIT_LIST_HEAD(&dentry->d_child); d_set_d_op(dentry, dentry->d_sb->s_d_op); if (dentry->d_op && dentry->d_op->d_init) { err = dentry->d_op->d_init(dentry); if (err) { if (dname_external(dentry)) kfree(external_name(dentry)); kmem_cache_free(dentry_cache, dentry); return NULL; } } if (unlikely(ext)) { pg_data_t *pgdat = page_pgdat(virt_to_page(ext)); mod_node_page_state(pgdat, NR_INDIRECTLY_RECLAIMABLE_BYTES, ksize(ext)); } this_cpu_inc(nr_dentry); return dentry; }

Contributors

PersonTokensPropCommitsCommitProp
Linus Torvalds (pre-git)15535.47%1438.89%
Al Viro8118.54%513.89%
Miklos Szeredi5913.50%12.78%
Roman Gushchin4610.53%12.78%
Andrew Morton388.70%38.33%
Linus Torvalds255.72%38.33%
Nicholas Piggin184.12%411.11%
Paul E. McKenney61.37%12.78%
Thomas Gleixner40.92%12.78%
Waiman Long30.69%12.78%
Vladimir Davydov10.23%12.78%
David Howells10.23%12.78%
Total437100.00%36100.00%

/** * d_alloc - allocate a dcache entry * @parent: parent of entry to allocate * @name: qstr of the name * * Allocates a dentry. It returns %NULL if there is insufficient memory * available. On a success the dentry is returned. The name passed in is * copied and the copy passed in may be reused after this call. */
struct dentry *d_alloc(struct dentry * parent, const struct qstr *name) { struct dentry *dentry = __d_alloc(parent->d_sb, name); if (!dentry) return NULL; dentry->d_flags |= DCACHE_RCUACCESS; spin_lock(&parent->d_lock); /* * don't need child lock because it is not subject * to concurrency here */ __dget_dlock(parent); dentry->d_parent = parent; list_add(&dentry->d_child, &parent->d_subdirs); spin_unlock(&parent->d_lock); return dentry; }

Contributors

PersonTokensPropCommitsCommitProp
Al Viro4044.44%222.22%
Nicholas Piggin2426.67%222.22%
Linus Torvalds (pre-git)2123.33%444.44%
Andrew Morton55.56%111.11%
Total90100.00%9100.00%

EXPORT_SYMBOL(d_alloc);
struct dentry *d_alloc_anon(struct super_block *sb) { return __d_alloc(sb, NULL); }

Contributors

PersonTokensPropCommitsCommitProp
Miklos Szeredi20100.00%1100.00%
Total20100.00%1100.00%

EXPORT_SYMBOL(d_alloc_anon);
struct dentry *d_alloc_cursor(struct dentry * parent) { struct dentry *dentry = d_alloc_anon(parent->d_sb); if (dentry) { dentry->d_flags |= DCACHE_RCUACCESS | DCACHE_DENTRY_CURSOR; dentry->d_parent = dget(parent); } return dentry; }

Contributors

PersonTokensPropCommitsCommitProp
Al Viro4998.00%150.00%
Miklos Szeredi12.00%150.00%
Total50100.00%2100.00%

/** * d_alloc_pseudo - allocate a dentry (for lookup-less filesystems) * @sb: the superblock * @name: qstr of the name * * For a filesystem that just pins its dentries in memory and never * performs lookups at all, return an unhashed IS_ROOT dentry. */
struct dentry *d_alloc_pseudo(struct super_block *sb, const struct qstr *name) { return __d_alloc(sb, name); }

Contributors

PersonTokensPropCommitsCommitProp
Nicholas Piggin2388.46%133.33%
Al Viro27.69%133.33%
J. Bruce Fields13.85%133.33%
Total26100.00%3100.00%

EXPORT_SYMBOL(d_alloc_pseudo);
struct dentry *d_alloc_name(struct dentry *parent, const char *name) { struct qstr q; q.name = name; q.hash_len = hashlen_string(parent, name); return d_alloc(parent, &q); }

Contributors

PersonTokensPropCommitsCommitProp
James Morris4391.49%133.33%
George Spelvin24.26%133.33%
Linus Torvalds24.26%133.33%
Total47100.00%3100.00%

EXPORT_SYMBOL(d_alloc_name);
void d_set_d_op(struct dentry *dentry, const struct dentry_operations *op) { WARN_ON_ONCE(dentry->d_op); WARN_ON_ONCE(dentry->d_flags & (DCACHE_OP_HASH | DCACHE_OP_COMPARE | DCACHE_OP_REVALIDATE | DCACHE_OP_WEAK_REVALIDATE | DCACHE_OP_DELETE | DCACHE_OP_REAL)); dentry->d_op = op; if (!op) return; if (op->d_hash) dentry->d_flags |= DCACHE_OP_HASH; if (op->d_compare) dentry->d_flags |= DCACHE_OP_COMPARE; if (op->d_revalidate) dentry->d_flags |= DCACHE_OP_REVALIDATE; if (op->d_weak_revalidate) dentry->d_flags |= DCACHE_OP_WEAK_REVALIDATE; if (op->d_delete) dentry->d_flags |= DCACHE_OP_DELETE; if (op->d_prune) dentry->d_flags |= DCACHE_OP_PRUNE; if (op->d_real) dentry->d_flags |= DCACHE_OP_REAL; }

Contributors

PersonTokensPropCommitsCommitProp
Nicholas Piggin9870.00%116.67%
Jeff Layton1410.00%116.67%
Sage Weil128.57%116.67%
Miklos Szeredi96.43%116.67%
David Howells53.57%116.67%
Linus Torvalds21.43%116.67%
Total140100.00%6100.00%

EXPORT_SYMBOL(d_set_d_op); /* * d_set_fallthru - Mark a dentry as falling through to a lower layer * @dentry - The dentry to mark * * Mark a dentry as falling through to the lower layer (as set with * d_pin_lower()). This flag may be recorded on the medium. */
void d_set_fallthru(struct dentry *dentry) { spin_lock(&dentry->d_lock); dentry->d_flags |= DCACHE_FALLTHRU; spin_unlock(&dentry->d_lock); }

Contributors

PersonTokensPropCommitsCommitProp
David Howells32100.00%1100.00%
Total32100.00%1100.00%

EXPORT_SYMBOL(d_set_fallthru);
static unsigned d_flags_for_inode(struct inode *inode) { unsigned add_flags = DCACHE_REGULAR_TYPE; if (!inode) return DCACHE_MISS_TYPE; if (S_ISDIR(inode->i_mode)) { add_flags = DCACHE_DIRECTORY_TYPE; if (unlikely(!(inode->i_opflags & IOP_LOOKUP))) { if (unlikely(!inode->i_op->lookup)) add_flags = DCACHE_AUTODIR_TYPE; else inode->i_opflags |= IOP_LOOKUP; } goto type_determined; } if (unlikely(!(inode->i_opflags & IOP_NOFOLLOW))) { if (unlikely(inode->i_op->get_link)) { add_flags = DCACHE_SYMLINK_TYPE; goto type_determined; } inode->i_opflags |= IOP_NOFOLLOW; } if (unlikely(!S_ISREG(inode->i_mode))) add_flags = DCACHE_SPECIAL_TYPE; type_determined: if (unlikely(IS_AUTOMOUNT(inode))) add_flags |= DCACHE_NEED_AUTOMOUNT; return add_flags; }

Contributors

PersonTokensPropCommitsCommitProp
David Howells14188.68%337.50%
Linus Torvalds (pre-git)116.92%225.00%
Nicholas Piggin53.14%112.50%
Hirofumi Ogawa10.63%112.50%
Al Viro10.63%112.50%
Total159100.00%8100.00%


static void __d_instantiate(struct dentry *dentry, struct inode *inode) { unsigned add_flags = d_flags_for_inode(inode); WARN_ON(d_in_lookup(dentry)); spin_lock(&dentry->d_lock); hlist_add_head(&dentry->d_u.d_alias, &inode->i_dentry); raw_write_seqcount_begin(&dentry->d_seq); __d_set_inode_and_type(dentry, inode, add_flags); raw_write_seqcount_end(&dentry->d_seq); fsnotify_update_flags(dentry); spin_unlock(&dentry->d_lock); }

Contributors

PersonTokensPropCommitsCommitProp
Al Viro2830.11%642.86%
Linus Torvalds (pre-git)2526.88%214.29%
Nicholas Piggin1718.28%321.43%
David Howells1415.05%214.29%
Hirofumi Ogawa99.68%17.14%
Total93100.00%14100.00%

/** * d_instantiate - fill in inode information for a dentry * @entry: dentry to complete * @inode: inode to attach to this dentry * * Fill in inode information in the entry. * * This turns negative dentries into productive full members * of society. * * NOTE! This assumes that the inode count has been incremented * (or otherwise set) by the caller to indicate that it is now * in use by the dcache. */
void d_instantiate(struct dentry *entry, struct inode * inode) { BUG_ON(!hlist_unhashed(&entry->d_u.d_alias)); if (inode) { security_d_instantiate(entry, inode); spin_lock(&inode->i_lock); __d_instantiate(entry, inode); spin_unlock(&inode->i_lock); } }

Contributors

PersonTokensPropCommitsCommitProp
Hirofumi Ogawa2640.00%19.09%
Nicholas Piggin2335.38%436.36%
Al Viro1218.46%436.36%
Linus Torvalds (pre-git)46.15%218.18%
Total65100.00%11100.00%

EXPORT_SYMBOL(d_instantiate); /* * This should be equivalent to d_instantiate() + unlock_new_inode(), * with lockdep-related part of unlock_new_inode() done before * anything else. Use that instead of open-coding d_instantiate()/ * unlock_new_inode() combinations. */
void d_instantiate_new(struct dentry *entry, struct inode *inode) { BUG_ON(!hlist_unhashed(&entry->d_u.d_alias)); BUG_ON(!inode); lockdep_annotate_inode_mutex_key(inode); security_d_instantiate(entry, inode); spin_lock(&inode->i_lock); __d_instantiate(entry, inode); WARN_ON(!(inode->i_state & I_NEW)); inode->i_state &= ~I_NEW; smp_mb(); wake_up_bit(&inode->i_state, __I_NEW); spin_unlock(&inode->i_lock); }

Contributors

PersonTokensPropCommitsCommitProp
Al Viro102100.00%1100.00%
Total102100.00%1100.00%

EXPORT_SYMBOL(d_instantiate_new); /** * d_instantiate_no_diralias - instantiate a non-aliased dentry * @entry: dentry to complete * @inode: inode to attach to this dentry * * Fill in inode information in the entry. If a directory alias is found, then * return an error (and drop inode). Together with d_materialise_unique() this * guarantees that a directory inode may never have more than one alias. */
int d_instantiate_no_diralias(struct dentry *entry, struct inode *inode) { BUG_ON(!hlist_unhashed(&entry->d_u.d_alias)); security_d_instantiate(entry, inode); spin_lock(&inode->i_lock); if (S_ISDIR(inode->i_mode) && !hlist_empty(&inode->i_dentry)) { spin_unlock(&inode->i_lock); iput(inode); return -EBUSY; } __d_instantiate(entry, inode); spin_unlock(&inode->i_lock); return 0; }

Contributors

PersonTokensPropCommitsCommitProp
Miklos Szeredi9090.91%133.33%
Al Viro99.09%266.67%
Total99100.00%3100.00%

EXPORT_SYMBOL(d_instantiate_no_diralias);
struct dentry *d_make_root(struct inode *root_inode) { struct dentry *res = NULL; if (root_inode) { res = d_alloc_anon(root_inode->i_sb); if (res) { res->d_flags |= DCACHE_RCUACCESS; d_instantiate(res, root_inode); } else { iput(root_inode); } } return res; }

Contributors

PersonTokensPropCommitsCommitProp
Al Viro6398.44%266.67%
Miklos Szeredi11.56%133.33%
Total64100.00%3100.00%

EXPORT_SYMBOL(d_make_root);
static struct dentry *__d_instantiate_anon(struct dentry *dentry, struct inode *inode, bool disconnected) { struct dentry *res; unsigned add_flags; security_d_instantiate(dentry, inode); spin_lock(&inode->i_lock); res = __d_find_any_alias(inode); if (res) { spin_unlock(&inode->i_lock); dput(dentry); goto out_iput; } /* attach a disconnected dentry */ add_flags = d_flags_for_inode(inode); if (disconnected) add_flags |= DCACHE_DISCONNECTED; spin_lock(&dentry->d_lock); __d_set_inode_and_type(dentry, inode, add_flags); hlist_add_head(&dentry->d_u.d_alias, &inode->i_dentry); if (!disconnected) { hlist_bl_lock(&dentry->d_sb->s_roots); hlist_bl_add_head(&dentry->d_hash, &dentry->d_sb->s_roots); hlist_bl_unlock(&dentry->d_sb->s_roots); } spin_unlock(&dentry->d_lock); spin_unlock(&inode->i_lock); return dentry; out_iput: iput(inode); return res; }

Contributors

PersonTokensPropCommitsCommitProp
Neil Brown5528.65%313.04%
Nicholas Piggin3216.67%417.39%
Miklos Szeredi3015.62%14.35%
David Howells178.85%28.70%
Christoph Hellwig147.29%313.04%
Andrew Morton136.77%14.35%
Linus Torvalds (pre-git)115.73%313.04%
J. Bruce Fields105.21%28.70%
Al Viro94.69%313.04%
Fengguang Wu10.52%14.35%
Total192100.00%23100.00%


struct dentry *d_instantiate_anon(struct dentry *dentry, struct inode *inode) { return __d_instantiate_anon(dentry, inode, true); }

Contributors

PersonTokensPropCommitsCommitProp
Miklos Szeredi27100.00%1100.00%
Total27100.00%1100.00%

EXPORT_SYMBOL(d_instantiate_anon);
static struct dentry *__d_obtain_alias(struct inode *inode, bool disconnected) { struct dentry *tmp; struct dentry *res; if (!inode) return ERR_PTR(-ESTALE); if (IS_ERR(inode)) return ERR_CAST(inode); res = d_find_any_alias(inode); if (res) goto out_iput; tmp = d_alloc_anon(inode->i_sb); if (!tmp) { res = ERR_PTR(-ENOMEM); goto out_iput; } return __d_instantiate_anon(tmp, inode, disconnected); out_iput: iput(inode); return res; }

Contributors

PersonTokensPropCommitsCommitProp
Miklos Szeredi9988.39%133.33%
Christoph Hellwig1311.61%266.67%
Total112100.00%3100.00%

/** * d_obtain_alias - find or allocate a DISCONNECTED dentry for a given inode * @inode: inode to allocate the dentry for * * Obtain a dentry for an inode resulting from NFS filehandle conversion or * similar open by handle operations. The returned dentry may be anonymous, * or may have a full name (if the inode was already in the cache). * * When called on a directory inode, we must ensure that the inode only ever * has one dentry. If a dentry is found, that is returned instead of * allocating a new one. * * On successful return, the reference to the inode has been transferred * to the dentry. In case of an error the reference on the inode is released. * To make it easier to use in export operations a %NULL or IS_ERR inode may * be passed in and the error will be propagated to the return value, * with a %NULL @inode replaced by ERR_PTR(-ESTALE). */
struct dentry *d_obtain_alias(struct inode *inode) { return __d_obtain_alias(inode, true); }

Contributors

PersonTokensPropCommitsCommitProp
J. Bruce Fields1995.00%150.00%
Miklos Szeredi15.00%150.00%
Total20100.00%2100.00%

EXPORT_SYMBOL(d_obtain_alias); /** * d_obtain_root - find or allocate a dentry for a given inode * @inode: inode to allocate the dentry for * * Obtain an IS_ROOT dentry for the root of a filesystem. * * We must ensure that directory inodes only ever have one dentry. If a * dentry is found, that is returned instead of allocating a new one. * * On successful return, the reference to the inode has been transferred * to the dentry. In case of an error the reference on the inode is * released. A %NULL or IS_ERR inode may be passed in and will be the * error will be propagate to the return value, with a %NULL @inode * replaced by ERR_PTR(-ESTALE). */
struct dentry *d_obtain_root(struct inode *inode) { return __d_obtain_alias(inode, false); }

Contributors

PersonTokensPropCommitsCommitProp
J. Bruce Fields1995.00%150.00%
Miklos Szeredi15.00%150.00%
Total20100.00%2100.00%

EXPORT_SYMBOL(d_obtain_root); /** * d_add_ci - lookup or allocate new dentry with case-exact name * @inode: the inode case-insensitive lookup has found * @dentry: the negative dentry that was passed to the parent's lookup func * @name: the case-exact name to be associated with the returned dentry * * This is to avoid filling the dcache with case-insensitive names to the * same inode, only the actual correct case is stored in the dcache for * case-insensitive filesystems. * * For a case-insensitive lookup match and if the the case-exact dentry * already exists in in the dcache, use it and return it. * * If no entry exists with the exact case name, allocate new dentry with * the exact case, and return the spliced entry. */
struct dentry *d_add_ci(struct dentry *dentry, struct inode *inode, struct qstr *name) { struct dentry *found, *res; /* * First check if a dentry matching the name already exists, * if not go ahead and create it now. */ found = d_hash_and_lookup(dentry->d_parent, name); if (found) { iput(inode); return found; } if (d_in_lookup(dentry)) { found = d_alloc_parallel(dentry->d_parent, name, dentry->d_wait); if (IS_ERR(found) || !d_in_lookup(found)) { iput(inode); return found; } } else { found = d_alloc(dentry->d_parent, name); if (!found) { iput(inode); return ERR_PTR(-ENOMEM); } } res = d_splice_alias(inode, found); if (res) { dput(found); return res; } return found; }

Contributors

PersonTokensPropCommitsCommitProp
Barry Naujok7948.77%114.29%
Al Viro7848.15%457.14%
Christoph Hellwig53.09%228.57%
Total162100.00%7100.00%

EXPORT_SYMBOL(d_add_ci);
static inline bool d_same_name(const struct dentry *dentry, const struct dentry *parent, const struct qstr *name) { if (likely(!(parent->d_flags & DCACHE_OP_COMPARE))) { if (dentry->d_name.len != name->len) return false; return dentry_cmp(dentry, name->name, name->len) == 0; } return parent->d_op->d_compare(dentry, dentry->d_name.len, dentry->d_name.name, name) == 0; }

Contributors

PersonTokensPropCommitsCommitProp
Al Viro5354.08%150.00%
Linus Torvalds4545.92%150.00%
Total98100.00%2100.00%

/** * __d_lookup_rcu - search for a dentry (racy, store-free) * @parent: parent dentry * @name: qstr of name we wish to find * @seqp: returns d_seq value at the point where the dentry was found * Returns: dentry, or NULL * * __d_lookup_rcu is the dcache lookup function for rcu-walk name * resolution (store-free path walking) design described in * Documentation/filesystems/path-lookup.txt. * * This is not to be used outside core vfs. * * __d_lookup_rcu must only be used in rcu-walk mode, ie. with vfsmount lock * held, and rcu_read_lock held. The returned dentry must not be stored into * without taking d_lock and checking d_seq sequence count against @seq * returned here. * * A refcount may be taken on the found dentry with the d_rcu_to_refcount * function. * * Alternatively, __d_lookup_rcu may be called again to look up the child of * the returned dentry, so long as its parent's seqlock is checked after the * child is looked up. Thus, an interlocking stepping of sequence lock checks * is formed, giving integrity down the path walk. * * NOTE! The caller *has* to check the resulting dentry against the sequence * number we've returned before using any of the resulting dentry state! */
struct dentry *__d_lookup_rcu(const struct dentry *parent, const struct qstr *name, unsigned *seqp) { u64 hashlen = name->hash_len; const unsigned char *str = name->name; struct hlist_bl_head *b = d_hash(hashlen_hash(hashlen)); struct hlist_bl_node *node; struct dentry *dentry; /* * Note: There is significant duplication with __d_lookup_rcu which is * required to prevent single threaded performance regressions * especially on architectures where smp_rmb (in seqcounts) are costly. * Keep the two functions in sync. */ /* * The hash list is protected using RCU. * * Carefully use d_seq when comparing a candidate dentry, to avoid * races with d_move(). * * It is possible that concurrent renames can mess up our list * walk here and result in missing our dentry, resulting in the * false-negative result. d_lookup() protects against concurrent * renames using rename_lock seqlock. * * See Documentation/filesystems/path-lookup.txt for more details. */ hlist_bl_for_each_entry_rcu(dentry, node, b, d_hash) { unsigned seq; seqretry: /* * The dentry sequence count protects us from concurrent * renames, and thus protects parent and name fields. * * The caller must perform a seqcount check in order * to do anything useful with the returned dentry. * * NOTE! We do a "raw" seqcount_begin here. That means that * we don't wait for the sequence count to stabilize if it * is in the middle of a sequence change. If we do the slow * dentry compare, we will do seqretries until it is stable, * and if we end up with a successful lookup, we actually * want to exit RCU lookup anyway. * * Note that raw_seqcount_begin still *does* smp_rmb(), so * we are still guaranteed NUL-termination of ->d_name.name. */ seq = raw_seqcount_begin(&dentry->d_seq); if (dentry->d_parent != parent) continue; if (d_unhashed(dentry)) continue; if (unlikely(parent->d_flags & DCACHE_OP_COMPARE)) { int tlen; const char *tname; if (dentry->d_name.hash != hashlen_hash(hashlen)) continue; tlen = dentry->d_name.len; tname = dentry->d_name.name; /* we want a consistent (name,len) pair */ if (read_seqcount_retry(&dentry->d_seq, seq)) { cpu_relax(); goto seqretry; } if (parent->d_op->d_compare(dentry, tlen, tname, name) != 0) continue; } else { if (dentry->d_name.hash_len != hashlen) continue; if (dentry_cmp(dentry, str, hashlen_len(hashlen)) != 0) continue; } *seqp = seq; return dentry; } return NULL; }

Contributors

PersonTokensPropCommitsCommitProp
Nicholas Piggin11547.13%428.57%
Linus Torvalds6526.64%857.14%
Al Viro6325.82%17.14%
Namhyung Kim10.41%17.14%
Total244100.00%14100.00%

/** * d_lookup - search for a dentry * @parent: parent dentry * @name: qstr of name we wish to find * Returns: dentry, or NULL * * d_lookup searches the children of the parent dentry for the name in * question. If the dentry is found its reference count is incremented and the * dentry is returned. The caller must use dput to free the entry when it has * finished using it. %NULL is returned if the dentry does not exist. */
struct dentry *d_lookup(const struct dentry *parent, const struct qstr *name) { struct dentry *dentry; unsigned seq; do { seq = read_seqbegin(&rename_lock); dentry = __d_lookup(parent, name); if (dentry) break; } while (read_seqretry(&rename_lock, seq)); return dentry; }

Contributors

PersonTokensPropCommitsCommitProp
Andrew Morton4872.73%133.33%
Neil Brown1624.24%133.33%
Al Viro23.03%133.33%
Total66100.00%3100.00%

EXPORT_SYMBOL(d_lookup); /** * __d_lookup - search for a dentry (racy) * @parent: parent dentry * @name: qstr of name we wish to find * Returns: dentry, or NULL * * __d_lookup is like d_lookup, however it may (rarely) return a * false-negative result due to unrelated rename activity. * * __d_lookup is slightly faster by avoiding rename_lock read seqlock, * however it must be used carefully, eg. with a following d_lookup in * the case of failure. * * __d_lookup callers must be commented. */
struct dentry *__d_lookup(const struct dentry *parent, const struct qstr *name) { unsigned int hash = name->hash; struct hlist_bl_head *b = d_hash(hash); struct hlist_bl_node *node; struct dentry *found = NULL; struct dentry *dentry; /* * Note: There is significant duplication with __d_lookup_rcu which is * required to prevent single threaded performance regressions * especially on architectures where smp_rmb (in seqcounts) are costly. * Keep the two functions in sync. */ /* * The hash list is protected using RCU. * * Take d_lock when comparing a candidate dentry, to avoid races * with d_move(). * * It is possible that concurrent renames can mess up our list * walk here and result in missing our dentry, resulting in the * false-negative result. d_lookup() protects against concurrent * renames using rename_lock seqlock. * * See Documentation/filesystems/path-lookup.txt for more details. */ rcu_read_lock(); hlist_bl_for_each_entry_rcu(dentry, node, b, d_hash) { if (dentry->d_name.hash != hash) continue; spin_lock(&dentry->d_lock); if (dentry->d_parent != parent) goto next; if (d_unhashed(dentry)) goto next; if (!d_same_name(dentry, parent, name)) goto next; dentry->d_lockref.count++; found = dentry; spin_unlock(&dentry->d_lock); break; next: spin_unlock(&dentry->d_lock); } rcu_read_unlock(); return found; }

Contributors

PersonTokensPropCommitsCommitProp
Andrew Morton8049.38%419.05%
Neil Brown2616.05%14.76%
Linus Torvalds (pre-git)148.64%419.05%
Linus Torvalds127.41%29.52%
Nicholas Piggin116.79%419.05%
Paul E. McKenney84.94%14.76%
Al Viro53.09%29.52%
Waiman Long31.85%14.76%
Andi Kleen21.23%14.76%
Namhyung Kim10.62%14.76%
Total162100.00%21100.00%

/** * d_hash_and_lookup - hash the qstr then search for a dentry * @dir: Directory to search in * @name: qstr of name we wish to find * * On lookup failure NULL is returned; on bad name - ERR_PTR(-error) */
struct dentry *d_hash_and_lookup(struct dentry *dir, struct qstr *name) { /* * Check for a fs-specific hash function. Note that we must * calculate the standard hash first, as the d_op->d_hash() * routine may choose to leave the hash value unchanged. */ name->hash = full_name_hash(dir, name->name, name->len); if (dir->d_flags & DCACHE_OP_HASH) { int err = dir->d_op->d_hash(dir, name); if (unlikely(err < 0)) return ERR_PTR(err); } return d_lookup(dir, name); }

Contributors

PersonTokensPropCommitsCommitProp
Eric W. Biedermann6073.17%125.00%
Al Viro1720.73%125.00%
Nicholas Piggin33.66%125.00%
Linus Torvalds22.44%125.00%
Total82100.00%4100.00%

EXPORT_SYMBOL(d_hash_and_lookup); /* * When a file is deleted, we have two options: * - turn this dentry into a negative dentry * - unhash this dentry and free it. * * Usually, we want to just turn this into * a negative dentry, but if anybody else is * currently using the dentry or the inode * we can't do that and we fall back on removing * it from the hash queues and waiting for * it to be deleted later when it has no users */ /** * d_delete - delete a dentry * @dentry: The dentry to delete * * Turn the dentry into a negative dentry if possible, otherwise * remove it from the hash queues so it can be deleted later */
void d_delete(struct dentry * dentry) { struct inode *inode = dentry->d_inode; int isdir = d_is_dir(dentry); spin_lock(&inode->i_lock); spin_lock(&dentry->d_lock); /* * Are we the only user? */ if (dentry->d_lockref.count == 1) { dentry->d_flags &= ~DCACHE_CANT_MOUNT; dentry_unlink_inode(dentry); } else { __d_drop(dentry); spin_unlock(&dentry->d_lock); spin_unlock(&inode->i_lock); } fsnotify_nameremove(dentry, isdir); }

Contributors

PersonTokensPropCommitsCommitProp
Al Viro3333.33%214.29%
Linus Torvalds (pre-git)2828.28%642.86%
John McCutchan1515.15%17.14%
Nicholas Piggin1212.12%321.43%
Andrew Morton88.08%17.14%
Waiman Long33.03%17.14%
Total99100.00%14100.00%

EXPORT_SYMBOL(d_delete);
static void __d_rehash(struct dentry *entry) { struct hlist_bl_head *b = d_hash(entry->d_name.hash); hlist_bl_lock(b); hlist_bl_add_head_rcu(&entry->d_hash, b); hlist_bl_unlock(b); }

Contributors

PersonTokensPropCommitsCommitProp
Dipankar Sarma1942.22%120.00%
Al Viro1226.67%120.00%
Nicholas Piggin1124.44%120.00%
Christoph Hellwig24.44%120.00%
Linus Torvalds12.22%120.00%
Total45100.00%5100.00%

/** * d_rehash - add an entry back to the hash * @entry: dentry to add to the hash * * Adds a dentry to the hash according to its name. */
void d_rehash(struct dentry * entry) { spin_lock(&entry->d_lock); __d_rehash(entry); spin_unlock(&entry->d_lock); }

Contributors

PersonTokensPropCommitsCommitProp
Andrew Morton1135.48%225.00%
David Howells929.03%112.50%
Linus Torvalds (pre-git)722.58%337.50%
Dipankar Sarma39.68%112.50%
Al Viro13.23%112.50%
Total31100.00%8100.00%

EXPORT_SYMBOL(d_rehash);
static inline unsigned start_dir_add(struct inode *dir) { for (;;) { unsigned n = dir->i_dir_seq; if (!(n & 1) && cmpxchg(&dir->i_dir_seq, n, n + 1) == n) return n; cpu_relax(); } }

Contributors

PersonTokensPropCommitsCommitProp
Al Viro57100.00%1100.00%
Total57100.00%1100.00%


static inline void end_dir_add(struct inode *dir, unsigned n) { smp_store_release(&dir->i_dir_seq, n + 2); }

Contributors

PersonTokensPropCommitsCommitProp
Al Viro27100.00%1100.00%
Total27100.00%1100.00%


static void d_wait_lookup(struct dentry *dentry) { if (d_in_lookup(dentry)) { DECLARE_WAITQUEUE(wait, current); add_wait_queue(dentry->d_wait, &wait); do { set_current_state(TASK_UNINTERRUPTIBLE); spin_unlock(&dentry->d_lock); schedule(); spin_lock(&dentry->d_lock); } while (d_in_lookup(dentry)); } }

Contributors

PersonTokensPropCommitsCommitProp
Al Viro72100.00%1100.00%
Total72100.00%1100.00%


struct dentry *d_alloc_parallel(struct dentry *parent, const struct qstr *name, wait_queue_head_t *wq) { unsigned int hash = name->hash; struct hlist_bl_head *b = in_lookup_hash(parent, hash); struct hlist_bl_node *node; struct dentry *new = d_alloc(parent, name); struct dentry *dentry; unsigned seq, r_seq, d_seq; if (unlikely(!new)) return ERR_PTR(-ENOMEM); retry: rcu_read_lock(); seq = smp_load_acquire(&parent->d_inode->i_dir_seq); r_seq = read_seqbegin(&rename_lock); dentry = __d_lookup_rcu(parent, name, &d_seq); if (unlikely(dentry)) { if (!lockref_get_not_dead(&dentry->d_lockref)) { rcu_read_unlock(); goto retry; } if (read_seqcount_retry(&dentry->d_seq, d_seq)) { rcu_read_unlock(); dput(dentry); goto retry; } rcu_read_unlock(); dput(new); return dentry; } if (unlikely(read_seqretry(&rename_lock, r_seq))) { rcu_read_unlock(); goto retry; } if (unlikely(seq & 1)) { rcu_read_unlock(); goto retry; } hlist_bl_lock(b); if (unlikely(READ_ONCE(parent->d_inode->i_dir_seq) != seq)) { hlist_bl_unlock(b); rcu_read_unlock(); goto retry; } /* * No changes for the parent since the beginning of d_lookup(). * Since all removals from the chain happen with hlist_bl_lock(), * any potential in-lookup matches are going to stay here until * we unlock the chain. All fields are stable in everything * we encounter. */ hlist_bl_for_each_entry(dentry, node, b, d_u.d_in_lookup_hash) { if (dentry->d_name.hash != hash) continue; if (dentry->d_parent != parent) continue; if (!d_same_name(dentry, parent, name)) continue; hlist_bl_unlock(b); /* now we can try to grab a reference */ if (!lockref_get_not_dead(&dentry->d_lockref)) { rcu_read_unlock(); goto retry; } rcu_read_unlock(); /* * somebody is likely to be still doing lookup for it; * wait for them to finish */ spin_lock(&dentry->d_lock); d_wait_lookup(dentry); /* * it's not in-lookup anymore; in principle we should repeat * everything from dcache lookup, but it's likely to be what * d_lookup() would've found anyway. If it is, just return it; * otherwise we really have to repeat the whole thing. */ if (unlikely(dentry->d_name.hash != hash)) goto mismatch; if (unlikely(dentry->d_parent != parent)) goto mismatch; if (unlikely(d_unhashed(dentry))) goto mismatch; if (unlikely(!d_same_name(dentry, parent, name))) goto mismatch; /* OK, it *is* a hashed match; return it */ spin_unlock(&dentry->d_lock); dput(new); return dentry; } rcu_read_unlock(); /* we can't take ->d_lock here; it's OK, though. */ new->d_flags |= DCACHE_PAR_LOOKUP; new->d_wait = wq; hlist_bl_add_head_rcu(&new->d_u.d_in_lookup_hash, b); hlist_bl_unlock(b); return new; mismatch: spin_unlock(&dentry->d_lock); dput(dentry); goto retry; }

Contributors

PersonTokensPropCommitsCommitProp
Al Viro46095.83%571.43%
Will Deacon204.17%228.57%
Total480100.00%7100.00%

EXPORT_SYMBOL(d_alloc_parallel);
void __d_lookup_done(struct dentry *dentry) { struct hlist_bl_head *b = in_lookup_hash(dentry->d_parent, dentry->d_name.hash); hlist_bl_lock(b); dentry->d_flags &= ~DCACHE_PAR_LOOKUP; __hlist_bl_del(&dentry->d_u.d_in_lookup_hash); wake_up_all(dentry->d_wait); dentry->d_wait = NULL; hlist_bl_unlock(b); INIT_HLIST_NODE(&dentry->d_u.d_alias); INIT_LIST_HEAD(&dentry->d_lru); }

Contributors

PersonTokensPropCommitsCommitProp
Al Viro86100.00%3100.00%
Total86100.00%3100.00%

EXPORT_SYMBOL(__d_lookup_done); /* inode->i_lock held if inode is non-NULL */
static inline void __d_add(struct dentry *dentry, struct inode *inode) { struct inode *dir = NULL; unsigned n; spin_lock(&dentry->d_lock); if (unlikely(d_in_lookup(dentry))) { dir = dentry->d_parent->d_inode; n = start_dir_add(dir); __d_lookup_done(dentry); } if (inode) { unsigned add_flags = d_flags_for_inode(inode); hlist_add_head(&dentry->d_u.d_alias, &inode->i_dentry); raw_write_seqcount_begin(&dentry->d_seq); __d_set_inode_and_type(dentry, inode, add_flags); raw_write_seqcount_end(&dentry->d_seq); fsnotify_update_flags(dentry); } __d_rehash(dentry); if (dir) end_dir_add(dir, n); spin_unlock(&dentry->d_lock); if (inode) spin_unlock(&inode->i_lock); }

Contributors

PersonTokensPropCommitsCommitProp
Al Viro162100.00%6100.00%
Total162100.00%6100.00%

/** * d_add - add dentry to hash queues * @entry: dentry to add * @inode: The inode to attach to this dentry * * This adds the entry to the hash queues and initializes @inode. * The entry was actually filled in earlier during d_alloc(). */
void d_add(struct dentry *entry, struct inode *inode) { if (inode) { security_d_instantiate(entry, inode); spin_lock(&inode->i_lock); } __d_add(entry, inode); }

Contributors

PersonTokensPropCommitsCommitProp
Al Viro43100.00%3100.00%
Total43100.00%3100.00%

EXPORT_SYMBOL(d_add); /** * d_exact_alias - find and hash an exact unhashed alias * @entry: dentry to add * @inode: The inode to go with this dentry * * If an unhashed dentry with the same name/parent and desired * inode already exists, hash and return it. Otherwise, return * NULL. * * Parent directory should be locked. */
struct dentry *d_exact_alias(struct dentry *entry, struct inode *inode) { struct dentry *alias; unsigned int hash = entry->d_name.hash; spin_lock(&inode->i_lock); hlist_for_each_entry(alias, &inode->i_dentry, d_u.d_alias) { /* * Don't need alias->d_lock here, because aliases with * d_parent == entry->d_parent are not subject to name or * parent changes, because the parent inode i_mutex is held. */ if (alias->d_name.hash != hash) continue; if (alias->d_parent != entry->d_parent) continue; if (!d_same_name(alias, entry->d_parent, &entry->d_name)) continue; spin_lock(&alias->d_lock); if (!d_unhashed(alias)) { spin_unlock(&alias->d_lock); alias = NULL; } else { __dget_dlock(alias); __d_rehash(alias); spin_unlock(&alias->d_lock); } spin_unlock(&inode->i_lock); return alias; } spin_unlock(&inode->i_lock); return NULL; }

Contributors

PersonTokensPropCommitsCommitProp
Al Viro164100.00%3100.00%
Total164100.00%3100.00%

EXPORT_SYMBOL(d_exact_alias); /** * dentry_update_name_case - update case insensitive dentry with a new name * @dentry: dentry to be updated * @name: new name * * Update a case insensitive dentry with new case of name. * * dentry must have been returned by d_lookup with name @name. Old and new * name lengths must match (ie. no d_compare which allows mismatched name * lengths). * * Parent inode i_mutex must be held over d_lookup and into this call (to * keep renames and concurrent inserts, and readdir(2) away). */
void dentry_update_name_case(struct dentry *dentry, const struct qstr *name) { BUG_ON(!inode_is_locked(dentry->d_parent->d_inode)); BUG_ON(dentry->d_name.len != name->len); /* d_lookup gives this */ spin_lock(&dentry->d_lock); write_seqcount_begin(&dentry->d_seq); memcpy((unsigned char *)dentry->d_name.name, name->name, name->len); write_seqcount_end(&dentry->d_seq); spin_unlock(&dentry->d_lock); }

Contributors

PersonTokensPropCommitsCommitProp
Nicholas Piggin9395.88%240.00%
Linus Torvalds22.06%120.00%
Al Viro22.06%240.00%
Total97100.00%5100.00%

EXPORT_SYMBOL(dentry_update_name_case);
static void swap_names(struct dentry *dentry, struct dentry *target) { if (unlikely(dname_external(target))) { if (unlikely(dname_external(dentry))) { /* * Both external: swap the pointers */ swap(target->d_name.name, dentry->d_name.name); } else { /* * dentry:internal, target:external. Steal target's * storage and make target internal. */ memcpy(target->d_iname, dentry->d_name.name, dentry->d_name.len + 1); dentry->d_name.name = target->d_name.name; target->d_name.name = target->d_iname; } } else { if (unlikely(dname_external(dentry))) { /* * dentry:external, target:internal. Give dentry's * storage to target and make dentry internal */ memcpy(dentry->d_iname, target->d_name.name, target->d_name.len + 1); target->d_name.name = dentry->d_name.name; dentry->d_name.name = dentry->d_iname; } else { /* * Both are internal. */ unsigned int i; BUILD_BUG_ON(!IS_ALIGNED(DNAME_INLINE_LEN, sizeof(long))); for (i = 0; i < DNAME_INLINE_LEN / sizeof(long); i++) { swap(((long *) &dentry->d_iname)[i], ((long *) &target->d_iname)[i]); } } } swap(dentry->d_name.hash_len, target->d_name.hash_len); }

Contributors

PersonTokensPropCommitsCommitProp
Andrew Morton6726.80%222.22%
Miklos Szeredi6124.40%111.11%
Linus Torvalds (pre-git)5220.80%111.11%
Nicholas Piggin3614.40%111.11%
J. Bruce Fields218.40%111.11%
Al Viro104.00%111.11%
Linus Torvalds20.80%111.11%
Fengguang Wu10.40%111.11%
Total250100.00%9100.00%


static void copy_name(struct dentry *dentry, struct dentry *target) { struct external_name *old_name = NULL; if (unlikely(dname_external(dentry))) old_name = external_name(dentry); if (unlikely(dname_external(target))) { atomic_inc(&external_name(target)->u.count); dentry->d_name = target->d_name; } else { memcpy(dentry->d_iname, target->d_name.name, target->d_name.len + 1); dentry->d_name.name = dentry->d_iname; dentry->d_name.hash_len = target->d_name.hash_len; } if (old_name && likely(atomic_dec_and_test(&old_name->u.count))) call_rcu(&old_name->u.head, __d_free_external_name); }

Contributors

PersonTokensPropCommitsCommitProp
Al Viro14396.62%150.00%
Roman Gushchin53.38%150.00%
Total148100.00%2100.00%

/* * __d_move - move a dentry * @dentry: entry to move * @target: new dentry * @exchange: exchange the two dentries * * Update the dcache to reflect the move of a file name. Negative * dcache entries should not be moved in this way. Caller must hold * rename_lock, the i_mutex of the source and target directories, * and the sb->s_vfs_rename_mutex if they differ. See lock_rename(). */
static void __d_move(struct dentry *dentry, struct dentry *target, bool exchange) { struct dentry *old_parent, *p; struct inode *dir = NULL; unsigned n; WARN_ON(!dentry->d_inode); if (WARN_ON(dentry == target)) return; BUG_ON(d_ancestor(target, dentry)); old_parent = dentry->d_parent; p = d_ancestor(old_parent, target); if (IS_ROOT(dentry)) { BUG_ON(p); spin_lock(&target->d_parent->d_lock); } else if (!p) { /* target is not a descendent of dentry->d_parent */ spin_lock(&target->d_parent->d_lock); spin_lock_nested(&old_parent->d_lock, DENTRY_D_LOCK_NESTED); } else { BUG_ON(p == dentry); spin_lock(&old_parent->d_lock); if (p != target) spin_lock_nested(&target->d_parent->d_lock, DENTRY_D_LOCK_NESTED); } spin_lock_nested(&dentry->d_lock, 2); spin_lock_nested(&target->d_lock, 3); if (unlikely(d_in_lookup(target))) { dir = target->d_parent->d_inode; n = start_dir_add(dir); __d_lookup_done(target); } write_seqcount_begin(&dentry->d_seq); write_seqcount_begin_nested(&target->d_seq, DENTRY_D_LOCK_NESTED); /* unhash both */ if (!d_unhashed(dentry)) ___d_drop(dentry); if (!d_unhashed(target)) ___d_drop(target); /* ... and switch them in the tree */ dentry->d_parent = target->d_parent; if (!exchange) { copy_name(dentry, target); target->d_hash.pprev = NULL; dentry->d_parent->d_lockref.count++; if (dentry == old_parent) dentry->d_flags |= DCACHE_RCUACCESS; else WARN_ON(!--old_parent->d_lockref.count); } else { target->d_parent = old_parent; swap_names(dentry, target); list_move(&target->d_child, &target->d_parent->d_subdirs); __d_rehash(target); fsnotify_update_flags(target); } list_move(&dentry->d_child, &dentry->d_parent->d_subdirs); __d_rehash(dentry); fsnotify_update_flags(dentry); write_seqcount_end(&target->d_seq); write_seqcount_end(&dentry->d_seq); if (dir) end_dir_add(dir, n); if (dentry->d_parent != old_parent) spin_unlock(&dentry->d_parent->d_lock); if (dentry != old_parent) spin_unlock(&old_parent->d_lock); spin_unlock(&target->d_lock); spin_unlock(&dentry->d_lock); }

Contributors

PersonTokensPropCommitsCommitProp
Al Viro27758.81%1252.17%
Nicholas Piggin13428.45%28.70%
Linus Torvalds (pre-git)316.58%521.74%
Neil Brown224.67%28.70%
Andrew Morton40.85%14.35%
John Stultz30.64%14.35%
Total471100.00%23100.00%

/* * d_move - move a dentry * @dentry: entry to move * @target: new dentry * * Update the dcache to reflect the move of a file name. Negative * dcache entries should not be moved in this way. See the locking * requirements for __d_move. */
void d_move(struct dentry *dentry, struct dentry *target) { write_seqlock(&rename_lock); __d_move(dentry, target, false); write_sequnlock(&rename_lock); }

Contributors

PersonTokensPropCommitsCommitProp
Al Viro2775.00%125.00%
Andrew Morton616.67%125.00%
Miklos Szeredi25.56%125.00%
Trond Myklebust12.78%125.00%
Total36100.00%4100.00%

EXPORT_SYMBOL(d_move); /* * d_exchange - exchange two dentries * @dentry1: first dentry * @dentry2: second dentry */
void d_exchange(struct dentry *dentry1, struct dentry *dentry2) { write_seqlock(&rename_lock); WARN_ON(!dentry1->d_inode); WARN_ON(!dentry2->d_inode); WARN_ON(IS_ROOT(dentry1)); WARN_ON(IS_ROOT(dentry2)); __d_move(dentry1, dentry2, true); write_sequnlock(&rename_lock); }

Contributors

PersonTokensPropCommitsCommitProp
Miklos Szeredi68100.00%1100.00%
Total68100.00%1100.00%

/** * d_ancestor - search for an ancestor * @p1: ancestor dentry * @p2: child dentry * * Returns the ancestor dentry of p2 which is a child of p1, if p1 is * an ancestor of p2, else NULL. */
struct dentry *d_ancestor(struct dentry *p1, struct dentry *p2) { struct dentry *p; for (p = p2; !IS_ROOT(p); p = p->d_parent) { if (p->d_parent == p1) return p; } return NULL; }

Contributors

PersonTokensPropCommitsCommitProp
Trond Myklebust4682.14%133.33%
Hirofumi Ogawa1017.86%266.67%
Total56100.00%3100.00%

/* * This helper attempts to cope with remotely renamed directories * * It assumes that the caller is already holding * dentry->d_parent->d_inode->i_mutex, and rename_lock * * Note: If ever the locking in lock_rename() changes, then please * remember to update this too... */
static int __d_unalias(struct inode *inode, struct dentry *dentry, struct dentry *alias) { struct mutex *m1 = NULL; struct rw_semaphore *m2 = NULL; int ret = -ESTALE; /* If alias and dentry share a parent, then no extra locks required */ if (alias->d_parent == dentry->d_parent) goto out_unalias; /* See lock_rename() */ if (!mutex_trylock(&dentry->d_sb->s_vfs_rename_mutex)) goto out_err; m1 = &dentry->d_sb->s_vfs_rename_mutex; if (!inode_trylock_shared(alias->d_parent->d_inode)) goto out_err; m2 = &alias->d_parent->d_inode->i_rwsem; out_unalias: __d_move(alias, dentry, false); ret = 0; out_err: if (m2) up_read(m2); if (m1) mutex_unlock(m1); return ret; }

Contributors

PersonTokensPropCommitsCommitProp
Trond Myklebust12485.52%111.11%
Al Viro128.28%444.44%
Nicholas Piggin53.45%111.11%
Miklos Szeredi21.38%111.11%
J. Bruce Fields10.69%111.11%
Linus Torvalds (pre-git)10.69%111.11%
Total145100.00%9100.00%

/** * d_splice_alias - splice a disconnected dentry into the tree if one exists * @inode: the inode which may have a disconnected dentry * @dentry: a negative dentry which we want to point to the inode. * * If inode is a directory and has an IS_ROOT alias, then d_move that in * place of the given dentry and return it, else simply d_add the inode * to the dentry and return NULL. * * If a non-IS_ROOT directory is found, the filesystem is corrupt, and * we should error out: directories can't have multiple aliases. * * This is needed in the lookup routine of any filesystem that is exportable * (via knfsd) so that we can build dcache paths to directories effectively. * * If a dentry was found and moved, then it is returned. Otherwise NULL * is returned. This matches the expected return value of ->lookup. * * Cluster filesystems may call this function with a negative, hashed dentry. * In that case, we know that the inode will be a regular file, and also this * will only occur during atomic_open. So we need to check for the dentry * being already hashed only in the final case. */
struct dentry *d_splice_alias(struct inode *inode, struct dentry *dentry) { if (IS_ERR(inode)) return ERR_CAST(inode); BUG_ON(!d_unhashed(dentry)); if (!inode) goto out; security_d_instantiate(dentry, inode); spin_lock(&inode->i_lock); if (S_ISDIR(inode->i_mode)) { struct dentry *new = __d_find_any_alias(inode); if (unlikely(new)) { /* The reference to new ensures it remains an alias */ spin_unlock(&inode->i_lock); write_seqlock(&rename_lock); if (unlikely(d_ancestor(new, dentry))) { write_sequnlock(&rename_lock); dput(new); new = ERR_PTR(-ELOOP); pr_warn_ratelimited( "VFS: Lookup of '%s' in %s %s" " would have caused loop\n", dentry->d_name.name, inode->i_sb->s_type->name, inode->i_sb->s_id); } else if (!IS_ROOT(new)) { struct dentry *old_parent = dget(new->d_parent); int err = __d_unalias(inode, dentry, new); write_sequnlock(&rename_lock); if (err) { dput(new); new = ERR_PTR(err); } dput(old_parent); } else { __d_move(new, dentry, false); write_sequnlock(&rename_lock); } iput(inode); return new; } } out: __d_add(dentry, inode); return NULL; }

Contributors

PersonTokensPropCommitsCommitProp
Al Viro14052.24%847.06%
J. Bruce Fields8732.46%423.53%
David Howells207.46%15.88%
Eric W. Biedermann93.36%15.88%
Trond Myklebust72.61%15.88%
Michel Lespinasse31.12%15.88%
Hirofumi Ogawa20.75%15.88%
Total268100.00%17100.00%

EXPORT_SYMBOL(d_splice_alias); /* * Test whether new_dentry is a subdirectory of old_dentry. * * Trivially implemented using the dcache structure */ /** * is_subdir - is new dentry a subdirectory of old_dentry * @new_dentry: new dentry * @old_dentry: old dentry * * Returns true if new_dentry is a subdirectory of the parent (at any depth). * Returns false otherwise. * Caller must ensure that "new_dentry" is pinned before calling is_subdir() */
bool is_subdir(struct dentry *new_dentry, struct dentry *old_dentry) { bool result; unsigned seq; if (new_dentry == old_dentry) return true; do { /* for restarting inner loop in case of seq retry */ seq = read_seqbegin(&rename_lock); /* * Need rcu_readlock to protect against the d_parent trashing * due to d_move */ rcu_read_lock(); if (d_ancestor(old_dentry, new_dentry)) result = true; else result = false; rcu_read_unlock(); } while (read_seqretry(&rename_lock, seq)); return result; }

Contributors

PersonTokensPropCommitsCommitProp
Linus Torvalds (pre-git)2834.57%114.29%
Andrew Morton2632.10%228.57%
Hirofumi Ogawa1518.52%228.57%
Nicholas Piggin78.64%114.29%
Yaowei Bai56.17%114.29%
Total81100.00%7100.00%

EXPORT_SYMBOL(is_subdir);
static enum d_walk_ret d_genocide_kill(void *data, struct dentry *dentry) { struct dentry *root = data; if (dentry != root) { if (d_unhashed(dentry) || !dentry->d_inode) return D_WALK_SKIP; if (!(dentry->d_flags & DCACHE_GENOCIDE)) { dentry->d_flags |= DCACHE_GENOCIDE; dentry->d_lockref.count--; } } return D_WALK_CONTINUE; }

Contributors

PersonTokensPropCommitsCommitProp
Miklos Szeredi4357.33%250.00%
Linus Torvalds (pre-git)3040.00%125.00%
Nicholas Piggin22.67%125.00%
Total75100.00%4100.00%


void d_genocide(struct dentry *parent) { d_walk(parent, parent, d_genocide_kill); }

Contributors

PersonTokensPropCommitsCommitProp
Miklos Szeredi1052.63%120.00%
Nicholas Piggin631.58%240.00%
Linus Torvalds210.53%120.00%
Linus Torvalds (pre-git)15.26%120.00%
Total19100.00%5100.00%

EXPORT_SYMBOL(d_genocide);
void d_tmpfile(struct dentry *dentry, struct inode *inode) { inode_dec_link_count(inode); BUG_ON(dentry->d_name.name != dentry->d_iname || !hlist_unhashed(&dentry->d_u.d_alias) || !d_unlinked(dentry)); spin_lock(&dentry->d_parent->d_lock); spin_lock_nested(&dentry->d_lock, DENTRY_D_LOCK_NESTED); dentry->d_name.len = sprintf(dentry->d_iname, "#%llu", (unsigned long long)inode->i_ino); spin_unlock(&dentry->d_lock); spin_unlock(&dentry->d_parent->d_lock); d_instantiate(dentry, inode); }

Contributors

PersonTokensPropCommitsCommitProp
Al Viro9075.63%375.00%
Linus Torvalds (pre-git)2924.37%125.00%
Total119100.00%4100.00%

EXPORT_SYMBOL(d_tmpfile); static __initdata unsigned long dhash_entries;
static int __init set_dhash_entries(char *str) { if (!str) return 0; dhash_entries = simple_strtoul(str, &str, 0); return 1; }

Contributors

PersonTokensPropCommitsCommitProp
Andrew Morton34100.00%1100.00%
Total34100.00%1100.00%

__setup("dhash_entries=", set_dhash_entries);
static void __init dcache_init_early(void) { /* If hashes are distributed across NUMA nodes, defer * hash allocation until vmalloc space is available. */ if (hashdist) return; dentry_hashtable = alloc_large_system_hash("Dentry cache", sizeof(struct hlist_bl_head), dhash_entries, 13, HASH_EARLY | HASH_ZERO, &d_hash_shift, NULL, 0, 0); d_hash_shift = 32 - d_hash_shift; }

Contributors

PersonTokensPropCommitsCommitProp
Linus Torvalds (pre-git)1529.41%533.33%
David Howells1019.61%16.67%
Brent Casavant917.65%213.33%
Alexey Dobriyan713.73%213.33%
Andrew Morton59.80%213.33%
Pavel Tatashin23.92%16.67%
Tim Bird23.92%16.67%
Linus Torvalds11.96%16.67%
Total51100.00%15100.00%


static void __init dcache_init(void) { /* * A constructor could be added for stable state like the lists, * but it is probably not worth it because of the cache nature * of the dcache. */ dentry_cache = KMEM_CACHE_USERCOPY(dentry, SLAB_RECLAIM_ACCOUNT|SLAB_PANIC|SLAB_MEM_SPREAD|SLAB_ACCOUNT, d_iname); /* Hash may have been set up in dcache_init_early */ if (!hashdist) return; dentry_hashtable = alloc_large_system_hash("Dentry cache", sizeof(struct hlist_bl_head), dhash_entries, 13, HASH_ZERO, &d_hash_shift, NULL, 0, 0); d_hash_shift = 32 - d_hash_shift; }

Contributors

PersonTokensPropCommitsCommitProp
Brent Casavant3044.12%17.14%
David Howells1319.12%17.14%
Alexey Dobriyan710.29%214.29%
Linus Torvalds (pre-git)57.35%321.43%
David Windsor34.41%17.14%
Vladimir Davydov22.94%17.14%
Pavel Tatashin22.94%17.14%
Paul Jackson22.94%17.14%
Tim Bird22.94%17.14%
Linus Torvalds11.47%17.14%
Cheng Renquan11.47%17.14%
Total68100.00%14100.00%

/* SLAB cache for __getname() consumers */ struct kmem_cache *names_cachep __read_mostly; EXPORT_SYMBOL(names_cachep);
void __init vfs_caches_init_early(void) { int i; for (i = 0; i < ARRAY_SIZE(in_lookup_hashtable); i++) INIT_HLIST_BL_HEAD(&in_lookup_hashtable[i]); dcache_init_early(); inode_init_early(); }

Contributors

PersonTokensPropCommitsCommitProp
Sebastian Andrzej Siewior2866.67%150.00%
David Howells1433.33%150.00%
Total42100.00%2100.00%


void __init vfs_caches_init(void) { names_cachep = kmem_cache_create_usercopy("names_cache", PATH_MAX, 0, SLAB_HWCACHE_ALIGN|SLAB_PANIC, 0, PATH_MAX, NULL); dcache_init(); inode_init(); files_init(); files_maxfiles_init(); mnt_init(); bdev_cache_init(); chrdev_init(); }

Contributors

PersonTokensPropCommitsCommitProp
Linus Torvalds (pre-git)2346.00%220.00%
Linus Torvalds1020.00%330.00%
David Windsor510.00%110.00%
Mel Gorman510.00%110.00%
Cheng Renquan36.00%110.00%
Andrew Morton24.00%110.00%
Andi Kleen24.00%110.00%
Total50100.00%10100.00%


Overall Contributors

PersonTokensPropCommitsCommitProp
Al Viro466739.42%8825.36%
Nicholas Piggin136811.56%257.20%
Miklos Szeredi9277.83%133.75%
Linus Torvalds8577.24%3610.37%
Linus Torvalds (pre-git)7996.75%4011.53%
David Howells4533.83%123.46%
Andrew Morton3943.33%174.90%
Neil Brown2041.72%72.02%
Dave Chinner1891.60%61.73%
Trond Myklebust1781.50%10.29%
Christoph Hellwig1741.47%92.59%
J. Bruce Fields1701.44%113.17%
Ian Kent1551.31%10.29%
Eric W. Biedermann1391.17%61.73%
John Ogness1291.09%20.58%
Roman Gushchin1140.96%10.29%
Kentaro Makita930.79%10.29%
Waiman Long890.75%20.58%
Barry Naujok800.68%10.29%
H Hartley Sweeten700.59%20.58%
Hirofumi Ogawa650.55%30.86%
Glauber de Oliveira Costa630.53%20.58%
James Morris430.36%10.29%
Vladimir Davydov420.35%30.86%
Brent Casavant390.33%20.58%
Eric Dumazet290.24%20.58%
Sebastian Andrzej Siewior280.24%10.29%
Will Deacon250.21%41.15%
Dipankar Sarma220.19%10.29%
Zheng Yan220.19%20.58%
Jan Blunck200.17%10.29%
John McCutchan180.15%10.29%
Jeff Layton150.13%20.58%
Paul E. McKenney140.12%20.58%
Alexey Dobriyan140.12%20.58%
Sage Weil120.10%10.29%
Sahitya Tummala80.07%10.29%
David Windsor80.07%20.58%
Ingo Molnar70.06%20.58%
Andi Kleen70.06%20.58%
Yaowei Bai60.05%10.29%
Mel Gorman50.04%10.29%
Amir Goldstein50.04%10.29%
Domen Puncer50.04%10.29%
Yan, Zheng50.04%10.29%
George Spelvin50.04%20.58%
Christoph Lameter40.03%10.29%
Tim Bird40.03%10.29%
Cheng Renquan40.03%10.29%
Thomas Gleixner40.03%10.29%
Dave Jones40.03%10.29%
Mark Rutland40.03%10.29%
Wei Fang40.03%10.29%
Pavel Tatashin40.03%10.29%
Andrey Ryabinin30.03%10.29%
Michel Lespinasse30.03%10.29%
John Stultz30.03%10.29%
Arnaldo Carvalho de Melo20.02%10.29%
Arnd Bergmann20.02%10.29%
He Kuang20.02%10.29%
Namhyung Kim20.02%10.29%
Fengguang Wu20.02%20.58%
Paul Jackson20.02%10.29%
Stephen D. Smalley10.01%10.29%
Benny Halevy10.01%10.29%
Joe Perches10.01%10.29%
Paul Gortmaker10.01%10.29%
Total11838100.00%347100.00%
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