diff options
Diffstat (limited to 'fs/dcache.c')
| -rw-r--r-- | fs/dcache.c | 101 |
1 files changed, 62 insertions, 39 deletions
diff --git a/fs/dcache.c b/fs/dcache.c index 16a53cc2cc02..b60ddc41d783 100644 --- a/fs/dcache.c +++ b/fs/dcache.c @@ -23,7 +23,7 @@ #include <linux/init.h> #include <linux/hash.h> #include <linux/cache.h> -#include <linux/module.h> +#include <linux/export.h> #include <linux/mount.h> #include <linux/file.h> #include <asm/uaccess.h> @@ -104,11 +104,11 @@ 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(struct dentry *parent, - unsigned long hash) +static inline struct hlist_bl_head *d_hash(const struct dentry *parent, + unsigned int hash) { - hash += ((unsigned long) parent ^ GOLDEN_RATIO_PRIME) / L1_CACHE_BYTES; - hash = hash ^ ((hash ^ GOLDEN_RATIO_PRIME) >> D_HASHBITS); + hash += (unsigned long) parent / L1_CACHE_BYTES; + hash = hash + (hash >> D_HASHBITS); return dentry_hashtable + (hash & D_HASHMASK); } @@ -137,6 +137,49 @@ int proc_nr_dentry(ctl_table *table, int write, void __user *buffer, } #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. + */ +static inline int dentry_cmp(const unsigned char *cs, size_t scount, + const unsigned char *ct, size_t tcount) +{ +#ifdef CONFIG_DCACHE_WORD_ACCESS + unsigned long a,b,mask; + + if (unlikely(scount != tcount)) + return 1; + + for (;;) { + a = *(unsigned long *)cs; + b = *(unsigned long *)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 = ~(~0ul << tcount*8); + return unlikely(!!((a ^ b) & mask)); +#else + if (scount != tcount) + return 1; + + do { + if (*cs != *ct) + return 1; + cs++; + ct++; + tcount--; + } while (tcount); + return 0; +#endif +} + static void __d_free(struct rcu_head *head) { struct dentry *dentry = container_of(head, struct dentry, d_u.d_rcu); @@ -1423,30 +1466,6 @@ struct dentry *d_instantiate_unique(struct dentry *entry, struct inode *inode) EXPORT_SYMBOL(d_instantiate_unique); -/** - * d_alloc_root - allocate root dentry - * @root_inode: inode to allocate the root for - * - * Allocate a root ("/") dentry for the inode given. The inode is - * instantiated and returned. %NULL is returned if there is insufficient - * memory or the inode passed is %NULL. - */ - -struct dentry * d_alloc_root(struct inode * root_inode) -{ - struct dentry *res = NULL; - - if (root_inode) { - static const struct qstr name = { .name = "/", .len = 1 }; - - res = __d_alloc(root_inode->i_sb, &name); - if (res) - d_instantiate(res, root_inode); - } - return res; -} -EXPORT_SYMBOL(d_alloc_root); - struct dentry *d_make_root(struct inode *root_inode) { struct dentry *res = NULL; @@ -1694,7 +1713,7 @@ EXPORT_SYMBOL(d_add_ci); * __d_lookup_rcu - search for a dentry (racy, store-free) * @parent: parent dentry * @name: qstr of name we wish to find - * @seq: returns d_seq value at the point where the dentry was found + * @seqp: returns d_seq value at the point where the dentry was found * @inode: returns dentry->d_inode when the inode was found valid. * Returns: dentry, or NULL * @@ -1717,8 +1736,9 @@ EXPORT_SYMBOL(d_add_ci); * child is looked up. Thus, an interlocking stepping of sequence lock checks * is formed, giving integrity down the path walk. */ -struct dentry *__d_lookup_rcu(struct dentry *parent, struct qstr *name, - unsigned *seq, struct inode **inode) +struct dentry *__d_lookup_rcu(const struct dentry *parent, + const struct qstr *name, + unsigned *seqp, struct inode **inode) { unsigned int len = name->len; unsigned int hash = name->hash; @@ -1748,6 +1768,7 @@ struct dentry *__d_lookup_rcu(struct dentry *parent, struct qstr *name, * See Documentation/filesystems/path-lookup.txt for more details. */ hlist_bl_for_each_entry_rcu(dentry, node, b, d_hash) { + unsigned seq; struct inode *i; const char *tname; int tlen; @@ -1756,7 +1777,7 @@ struct dentry *__d_lookup_rcu(struct dentry *parent, struct qstr *name, continue; seqretry: - *seq = read_seqcount_begin(&dentry->d_seq); + seq = read_seqcount_begin(&dentry->d_seq); if (dentry->d_parent != parent) continue; if (d_unhashed(dentry)) @@ -1771,7 +1792,7 @@ seqretry: * edge of memory when walking. If we could load this * atomically some other way, we could drop this check. */ - if (read_seqcount_retry(&dentry->d_seq, *seq)) + if (read_seqcount_retry(&dentry->d_seq, seq)) goto seqretry; if (unlikely(parent->d_flags & DCACHE_OP_COMPARE)) { if (parent->d_op->d_compare(parent, *inode, @@ -1788,6 +1809,7 @@ seqretry: * order to do anything useful with the returned dentry * anyway. */ + *seqp = seq; *inode = i; return dentry; } @@ -2382,6 +2404,7 @@ struct dentry *d_materialise_unique(struct dentry *dentry, struct inode *inode) if (d_ancestor(alias, dentry)) { /* Check for loops */ actual = ERR_PTR(-ELOOP); + spin_unlock(&inode->i_lock); } else if (IS_ROOT(alias)) { /* Is this an anonymous mountpoint that we * could splice into our tree? */ @@ -2391,7 +2414,7 @@ struct dentry *d_materialise_unique(struct dentry *dentry, struct inode *inode) goto found; } else { /* Nope, but we must(!) avoid directory - * aliasing */ + * aliasing. This drops inode->i_lock */ actual = __d_unalias(inode, dentry, alias); } write_sequnlock(&rename_lock); @@ -2968,7 +2991,7 @@ __setup("dhash_entries=", set_dhash_entries); static void __init dcache_init_early(void) { - int loop; + unsigned int loop; /* If hashes are distributed across NUMA nodes, defer * hash allocation until vmalloc space is available. @@ -2986,13 +3009,13 @@ static void __init dcache_init_early(void) &d_hash_mask, 0); - for (loop = 0; loop < (1 << d_hash_shift); loop++) + for (loop = 0; loop < (1U << d_hash_shift); loop++) INIT_HLIST_BL_HEAD(dentry_hashtable + loop); } static void __init dcache_init(void) { - int loop; + unsigned int loop; /* * A constructor could be added for stable state like the lists, @@ -3016,7 +3039,7 @@ static void __init dcache_init(void) &d_hash_mask, 0); - for (loop = 0; loop < (1 << d_hash_shift); loop++) + for (loop = 0; loop < (1U << d_hash_shift); loop++) INIT_HLIST_BL_HEAD(dentry_hashtable + loop); } |
