* the dcache entry is deleted or garbage collected.
*/
-#include <linux/config.h>
#include <linux/syscalls.h>
#include <linux/string.h>
#include <linux/mm.h>
#include <linux/seqlock.h>
#include <linux/swap.h>
#include <linux/bootmem.h>
+#include "internal.h"
int sysctl_vfs_cache_pressure __read_mostly = 100;
EXPORT_SYMBOL_GPL(sysctl_vfs_cache_pressure);
__cacheline_aligned_in_smp DEFINE_SPINLOCK(dcache_lock);
-static seqlock_t rename_lock __cacheline_aligned_in_smp = SEQLOCK_UNLOCKED;
+static __cacheline_aligned_in_smp DEFINE_SEQLOCK(rename_lock);
EXPORT_SYMBOL(dcache_lock);
cond_resched_lock(&dcache_lock);
tmp = dentry_unused.prev;
- if (unlikely(sb)) {
+ if (sb) {
/* Try to find a dentry for this sb, but don't try
* too hard, if they aren't near the tail they will
* be moved down again soon
dentry = list_entry(tmp, struct dentry, d_lru);
if (dentry->d_sb != sb)
continue;
- list_del(tmp);
- list_add(tmp, &dentry_unused);
+ list_move(tmp, &dentry_unused);
}
/*
* of the unused list for prune_dcache
*/
if (!atomic_read(&dentry->d_count)) {
- list_add(&dentry->d_lru, dentry_unused.prev);
+ list_add_tail(&dentry->d_lru, &dentry_unused);
dentry_stat.nr_unused++;
found++;
}
* (or otherwise set) by the caller to indicate that it is now
* in use by the dcache.
*/
-struct dentry *d_instantiate_unique(struct dentry *entry, struct inode *inode)
+static struct dentry *__d_instantiate_unique(struct dentry *entry,
+ struct inode *inode)
{
struct dentry *alias;
int len = entry->d_name.len;
const char *name = entry->d_name.name;
unsigned int hash = entry->d_name.hash;
- BUG_ON(!list_empty(&entry->d_alias));
- spin_lock(&dcache_lock);
- if (!inode)
- goto do_negative;
+ if (!inode) {
+ entry->d_inode = NULL;
+ return NULL;
+ }
+
list_for_each_entry(alias, &inode->i_dentry, d_alias) {
struct qstr *qstr = &alias->d_name;
if (memcmp(qstr->name, name, len))
continue;
dget_locked(alias);
- spin_unlock(&dcache_lock);
- BUG_ON(!d_unhashed(alias));
- iput(inode);
return alias;
}
+
list_add(&entry->d_alias, &inode->i_dentry);
-do_negative:
entry->d_inode = inode;
fsnotify_d_instantiate(entry, inode);
- spin_unlock(&dcache_lock);
- security_d_instantiate(entry, inode);
return NULL;
}
+
+struct dentry *d_instantiate_unique(struct dentry *entry, struct inode *inode)
+{
+ struct dentry *result;
+
+ BUG_ON(!list_empty(&entry->d_alias));
+
+ spin_lock(&dcache_lock);
+ result = __d_instantiate_unique(entry, inode);
+ spin_unlock(&dcache_lock);
+
+ if (!result) {
+ security_d_instantiate(entry, inode);
+ return NULL;
+ }
+
+ BUG_ON(!d_unhashed(result));
+ iput(inode);
+ return result;
+}
+
EXPORT_SYMBOL(d_instantiate_unique);
/**
hlist_add_head_rcu(&entry->d_hash, list);
}
+static void _d_rehash(struct dentry * entry)
+{
+ __d_rehash(entry, d_hash(entry->d_parent, entry->d_name.hash));
+}
+
/**
* d_rehash - add an entry back to the hash
* @entry: dentry to add to the hash
void d_rehash(struct dentry * entry)
{
- struct hlist_head *list = d_hash(entry->d_parent, entry->d_name.hash);
-
spin_lock(&dcache_lock);
spin_lock(&entry->d_lock);
- __d_rehash(entry, list);
+ _d_rehash(entry);
spin_unlock(&entry->d_lock);
spin_unlock(&dcache_lock);
}
*/
if (target < dentry) {
spin_lock(&target->d_lock);
- spin_lock(&dentry->d_lock);
+ spin_lock_nested(&dentry->d_lock, DENTRY_D_LOCK_NESTED);
} else {
spin_lock(&dentry->d_lock);
- spin_lock(&target->d_lock);
+ spin_lock_nested(&target->d_lock, DENTRY_D_LOCK_NESTED);
}
/* Move the dentry to the target hash queue, if on different bucket */
spin_unlock(&dcache_lock);
}
+/*
+ * Prepare an anonymous dentry for life in the superblock's dentry tree as a
+ * named dentry in place of the dentry to be replaced.
+ */
+static void __d_materialise_dentry(struct dentry *dentry, struct dentry *anon)
+{
+ struct dentry *dparent, *aparent;
+
+ switch_names(dentry, anon);
+ do_switch(dentry->d_name.len, anon->d_name.len);
+ do_switch(dentry->d_name.hash, anon->d_name.hash);
+
+ dparent = dentry->d_parent;
+ aparent = anon->d_parent;
+
+ dentry->d_parent = (aparent == anon) ? dentry : aparent;
+ list_del(&dentry->d_u.d_child);
+ if (!IS_ROOT(dentry))
+ list_add(&dentry->d_u.d_child, &dentry->d_parent->d_subdirs);
+ else
+ INIT_LIST_HEAD(&dentry->d_u.d_child);
+
+ anon->d_parent = (dparent == dentry) ? anon : dparent;
+ list_del(&anon->d_u.d_child);
+ if (!IS_ROOT(anon))
+ list_add(&anon->d_u.d_child, &anon->d_parent->d_subdirs);
+ else
+ INIT_LIST_HEAD(&anon->d_u.d_child);
+
+ anon->d_flags &= ~DCACHE_DISCONNECTED;
+}
+
+/**
+ * d_materialise_unique - introduce an inode into the tree
+ * @dentry: candidate dentry
+ * @inode: inode to bind to the dentry, to which aliases may be attached
+ *
+ * Introduces an dentry into the tree, substituting an extant disconnected
+ * root directory alias in its place if there is one
+ */
+struct dentry *d_materialise_unique(struct dentry *dentry, struct inode *inode)
+{
+ struct dentry *alias, *actual;
+
+ BUG_ON(!d_unhashed(dentry));
+
+ spin_lock(&dcache_lock);
+
+ if (!inode) {
+ actual = dentry;
+ dentry->d_inode = NULL;
+ goto found_lock;
+ }
+
+ /* See if a disconnected directory already exists as an anonymous root
+ * that we should splice into the tree instead */
+ if (S_ISDIR(inode->i_mode) && (alias = __d_find_alias(inode, 1))) {
+ spin_lock(&alias->d_lock);
+
+ /* Is this a mountpoint that we could splice into our tree? */
+ if (IS_ROOT(alias))
+ goto connect_mountpoint;
+
+ if (alias->d_name.len == dentry->d_name.len &&
+ alias->d_parent == dentry->d_parent &&
+ memcmp(alias->d_name.name,
+ dentry->d_name.name,
+ dentry->d_name.len) == 0)
+ goto replace_with_alias;
+
+ spin_unlock(&alias->d_lock);
+
+ /* Doh! Seem to be aliasing directories for some reason... */
+ dput(alias);
+ }
+
+ /* Add a unique reference */
+ actual = __d_instantiate_unique(dentry, inode);
+ if (!actual)
+ actual = dentry;
+ else if (unlikely(!d_unhashed(actual)))
+ goto shouldnt_be_hashed;
+
+found_lock:
+ spin_lock(&actual->d_lock);
+found:
+ _d_rehash(actual);
+ spin_unlock(&actual->d_lock);
+ spin_unlock(&dcache_lock);
+
+ if (actual == dentry) {
+ security_d_instantiate(dentry, inode);
+ return NULL;
+ }
+
+ iput(inode);
+ return actual;
+
+ /* Convert the anonymous/root alias into an ordinary dentry */
+connect_mountpoint:
+ __d_materialise_dentry(dentry, alias);
+
+ /* Replace the candidate dentry with the alias in the tree */
+replace_with_alias:
+ __d_drop(alias);
+ actual = alias;
+ goto found;
+
+shouldnt_be_hashed:
+ spin_unlock(&dcache_lock);
+ BUG();
+ goto shouldnt_be_hashed;
+}
+
/**
* d_path - return the path of a dentry
* @dentry: dentry to report
EXPORT_SYMBOL(d_genocide);
-extern void bdev_cache_init(void);
-extern void chrdev_init(void);
-
void __init vfs_caches_init_early(void)
{
dcache_init_early();
EXPORT_SYMBOL(d_invalidate);
EXPORT_SYMBOL(d_lookup);
EXPORT_SYMBOL(d_move);
+EXPORT_SYMBOL_GPL(d_materialise_unique);
EXPORT_SYMBOL(d_path);
EXPORT_SYMBOL(d_prune_aliases);
EXPORT_SYMBOL(d_rehash);
git.openpandora.org / pandora-kernel.git / blobdiff