Btrfs: dummy extent buffers for tree mod log

[~andy/linux] / fs / dcache.c

diff --git a/fs/dcache.c b/fs/dcache.c
index 16a53cc2cc02e079554742bfcd95c1f92d3608d4..bcbdb33fcc205aad37110be50752131aae894062 100644 (file)
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -104,7 +104,7 @@ 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,
+static inline struct hlist_bl_head *d_hash(const struct dentry *parent,
                                        unsigned long hash)
 {
        hash += ((unsigned long) parent ^ GOLDEN_RATIO_PRIME) / L1_CACHE_BYTES;
@@ -137,6 +137,26 @@ 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)
+{
+       if (scount != tcount)
+               return 1;
+
+       do {
+               if (*cs != *ct)
+                       return 1;
+               cs++;
+               ct++;
+               tcount--;
+       } while (tcount);
+       return 0;
+}
+
 static void __d_free(struct rcu_head *head)
 {
        struct dentry *dentry = container_of(head, struct dentry, d_u.d_rcu);
@@ -1717,8 +1737,9 @@ 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 +1769,7 @@ 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 +1778,7 @@ 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 +1793,7 @@ 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 +1810,7 @@ seqretry:
                 * order to do anything useful with the returned dentry
                 * anyway.
                 */
+               *seqp = seq;
                *inode = i;
                return dentry;
        }
@@ -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);
 }