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Merge branch 'dcache-cleanup'

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* dcache-cleanup:
  vfs: get rid of insane dentry hashing rules
This commit is contained in:
Linus Torvalds
2011-04-24 08:51:15 -07:00
parent 8f7544682c dea3667bc3
commit 5dd12af05c
2 changed files with 18 additions and 28 deletions
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42
fs/dcache.c
View File

@@ -164,8 +164,8 @@ static void d_free(struct dentry *dentry)
if (dentry->d_op && dentry->d_op->d_release) if (dentry->d_op && dentry->d_op->d_release)
dentry->d_op->d_release(dentry); dentry->d_op->d_release(dentry);
/* if dentry was never inserted into hash, immediate free is OK */ /* if dentry was never visible to RCU, immediate free is OK */
if (hlist_bl_unhashed(&dentry->d_hash)) if (!(dentry->d_flags & DCACHE_RCUACCESS))
__d_free(&dentry->d_u.d_rcu); __d_free(&dentry->d_u.d_rcu);
else else
call_rcu(&dentry->d_u.d_rcu, __d_free); call_rcu(&dentry->d_u.d_rcu, __d_free);
@@ -327,28 +327,19 @@ static struct dentry *d_kill(struct dentry *dentry, struct dentry *parent)
*/ */
void __d_drop(struct dentry *dentry) void __d_drop(struct dentry *dentry)
{ {
if (!(dentry->d_flags & DCACHE_UNHASHED)) { if (!d_unhashed(dentry)) {
struct hlist_bl_head *b; struct hlist_bl_head *b;
if (unlikely(dentry->d_flags & DCACHE_DISCONNECTED)) { if (unlikely(dentry->d_flags & DCACHE_DISCONNECTED))
b = &dentry->d_sb->s_anon; b = &dentry->d_sb->s_anon;
spin_lock_bucket(b); else
dentry->d_flags |= DCACHE_UNHASHED;
hlist_bl_del_init(&dentry->d_hash);
spin_unlock_bucket(b);
} else {
struct hlist_bl_head *b;
b = d_hash(dentry->d_parent, dentry->d_name.hash); b = d_hash(dentry->d_parent, dentry->d_name.hash);
spin_lock_bucket(b);
/* spin_lock_bucket(b);
* We may not actually need to put DCACHE_UNHASHED __hlist_bl_del(&dentry->d_hash);
* manipulations under the hash lock, but follow dentry->d_hash.pprev = NULL;
* the principle of least surprise. spin_unlock_bucket(b);
*/
dentry->d_flags |= DCACHE_UNHASHED; dentry_rcuwalk_barrier(dentry);
hlist_bl_del_rcu(&dentry->d_hash);
spin_unlock_bucket(b);
dentry_rcuwalk_barrier(dentry);
}
} }
} }
EXPORT_SYMBOL(__d_drop); EXPORT_SYMBOL(__d_drop);
@@ -1301,7 +1292,7 @@ struct dentry *d_alloc(struct dentry * parent, const struct qstr *name)
dname[name->len] = 0; dname[name->len] = 0;
dentry->d_count = 1; dentry->d_count = 1;
dentry->d_flags = DCACHE_UNHASHED; dentry->d_flags = 0;
spin_lock_init(&dentry->d_lock); spin_lock_init(&dentry->d_lock);
seqcount_init(&dentry->d_seq); seqcount_init(&dentry->d_seq);
dentry->d_inode = NULL; dentry->d_inode = NULL;
@@ -1603,10 +1594,9 @@ struct dentry *d_obtain_alias(struct inode *inode)
tmp->d_inode = inode; tmp->d_inode = inode;
tmp->d_flags |= DCACHE_DISCONNECTED; tmp->d_flags |= DCACHE_DISCONNECTED;
list_add(&tmp->d_alias, &inode->i_dentry); list_add(&tmp->d_alias, &inode->i_dentry);
bit_spin_lock(0, (unsigned long *)&tmp->d_sb->s_anon.first); spin_lock_bucket(&tmp->d_sb->s_anon);
tmp->d_flags &= ~DCACHE_UNHASHED;
hlist_bl_add_head(&tmp->d_hash, &tmp->d_sb->s_anon); hlist_bl_add_head(&tmp->d_hash, &tmp->d_sb->s_anon);
__bit_spin_unlock(0, (unsigned long *)&tmp->d_sb->s_anon.first); spin_unlock_bucket(&tmp->d_sb->s_anon);
spin_unlock(&tmp->d_lock); spin_unlock(&tmp->d_lock);
spin_unlock(&inode->i_lock); spin_unlock(&inode->i_lock);
security_d_instantiate(tmp, inode); security_d_instantiate(tmp, inode);
@@ -2087,7 +2077,7 @@ static void __d_rehash(struct dentry * entry, struct hlist_bl_head *b)
{ {
BUG_ON(!d_unhashed(entry)); BUG_ON(!d_unhashed(entry));
spin_lock_bucket(b); spin_lock_bucket(b);
entry->d_flags &= ~DCACHE_UNHASHED; entry->d_flags |= DCACHE_RCUACCESS;
hlist_bl_add_head_rcu(&entry->d_hash, b); hlist_bl_add_head_rcu(&entry->d_hash, b);
spin_unlock_bucket(b); spin_unlock_bucket(b);
} }

4
include/linux/dcache.h
View File

@@ -197,7 +197,7 @@ struct dentry_operations {
* typically using d_splice_alias. */ * typically using d_splice_alias. */
#define DCACHE_REFERENCED 0x0008 /* Recently used, don't discard. */ #define DCACHE_REFERENCED 0x0008 /* Recently used, don't discard. */
#define DCACHE_UNHASHED 0x0010 #define DCACHE_RCUACCESS 0x0010 /* Entry has ever been RCU-visible */
#define DCACHE_INOTIFY_PARENT_WATCHED 0x0020 #define DCACHE_INOTIFY_PARENT_WATCHED 0x0020
/* Parent inode is watched by inotify */ /* Parent inode is watched by inotify */
@@ -384,7 +384,7 @@ extern struct dentry *dget_parent(struct dentry *dentry);
static inline int d_unhashed(struct dentry *dentry) static inline int d_unhashed(struct dentry *dentry)
{ {
return (dentry->d_flags & DCACHE_UNHASHED); return hlist_bl_unhashed(&dentry->d_hash);
} }
static inline int d_unlinked(struct dentry *dentry) static inline int d_unlinked(struct dentry *dentry)