[PATCH] dcache.{c,h} cleanup

Dan Aloni (da-x@gmx.net)
Fri, 31 May 2002 11:28:06 +0300


include/linux/dcache.h:
+ change __inline__ to inline
+ use list_del_init() instead of list_del() + INIT_LIST_HEAD()
+ remove #define for obsolete shrink_dcache()
+ remove obsolete forward declaration of struct zone_struct.

fs/dcache.c:
+ use d_unhashed() instead of list_empty(&dentry->d_hash)
+ document d_free().
+ renamed dentry_iput() to d_iput(), for naming and prefix consistency.
+ added d_release() in order to refactor dput() and prune_one_dentry().
+ modified dput() to use d_release().
+ modified prune_one_dentry() to use d_release().

--- 2.5.19/include/linux/dcache.h Thu May 30 22:35:11 2002
+++ 2.5.19/include/linux/dcache.h Fri May 31 09:12:33 2002
@@ -44,19 +44,19 @@
#define init_name_hash() 0

/* partial hash update function. Assume roughly 4 bits per character */
-static __inline__ unsigned long partial_name_hash(unsigned long c, unsigned long prevhash)
+static inline unsigned long partial_name_hash(unsigned long c, unsigned long prevhash)
{
return (prevhash + (c << 4) + (c >> 4)) * 11;
}

/* Finally: cut down the number of bits to a int value (and try to avoid losing bits) */
-static __inline__ unsigned long end_name_hash(unsigned long hash)
+static inline unsigned long end_name_hash(unsigned long hash)
{
return (unsigned int) hash;
}

/* Compute the hash for a name string. */
-static __inline__ unsigned int full_name_hash(const unsigned char * name, unsigned int len)
+static inline unsigned int full_name_hash(const unsigned char * name, unsigned int len)
{
unsigned long hash = init_name_hash();
while (len--)
@@ -153,15 +153,14 @@
* timeouts or autofs deletes).
*/

-static __inline__ void d_drop(struct dentry * dentry)
+static inline void d_drop(struct dentry * dentry)
{
spin_lock(&dcache_lock);
- list_del(&dentry->d_hash);
- INIT_LIST_HEAD(&dentry->d_hash);
+ list_del_init(&dentry->d_hash);
spin_unlock(&dcache_lock);
}

-static __inline__ int dname_external(struct dentry *d)
+static inline int dname_external(struct dentry *d)
{
return d->d_name.name != d->d_iname;
}
@@ -181,8 +180,6 @@
extern void shrink_dcache_anon(struct list_head *);
extern int d_invalidate(struct dentry *);

-#define shrink_dcache() prune_dcache(0)
-struct zone_struct;
/* dcache memory management */
extern int shrink_dcache_memory(int, unsigned int);
extern void prune_dcache(int);
@@ -220,7 +217,7 @@
* The entry was actually filled in earlier during d_alloc().
*/

-static __inline__ void d_add(struct dentry * entry, struct inode * inode)
+static inline void d_add(struct dentry * entry, struct inode * inode)
{
d_instantiate(entry, inode);
d_rehash(entry);
@@ -254,7 +251,7 @@
* and call dget_locked() instead of dget().
*/

-static __inline__ struct dentry * dget(struct dentry *dentry)
+static inline struct dentry * dget(struct dentry *dentry)
{
if (dentry) {
if (!atomic_read(&dentry->d_count))
@@ -273,14 +270,14 @@
* Returns true if the dentry passed is not currently hashed.
*/

-static __inline__ int d_unhashed(struct dentry *dentry)
+static inline int d_unhashed(struct dentry *dentry)
{
return list_empty(&dentry->d_hash);
}

extern void dput(struct dentry *);

-static __inline__ int d_mountpoint(struct dentry *dentry)
+static inline int d_mountpoint(struct dentry *dentry)
{
return dentry->d_mounted;
}

--- 2.5.19/fs/dcache.c Thu May 30 22:35:37 2002
+++ 2.5.19/fs/dcache.c Fri May 31 09:12:16 2002
@@ -53,7 +53,13 @@
/* Statistics gathering. */
struct dentry_stat_t dentry_stat = {0, 0, 45, 0,};

-/* no dcache_lock, please */
+/*
+ * Frees the dentry. Calls the filesystem d_release() if defined.
+ * Frees the dentry name and the dentry from the kmem_cache.
+ *
+ * Call restrictions: dcache_lock not helded.
+ * Return state: 'dentry' is invalid.
+ */
static inline void d_free(struct dentry *dentry)
{
if (dentry->d_op && dentry->d_op->d_release)
@@ -67,9 +73,11 @@
/*
* Release the dentry's inode, using the filesystem
* d_iput() operation if defined.
- * Called with dcache_lock held, drops it.
+ *
+ * Call restrictions: dcache_lock held.
+ * Return state; dcache_lock not held.
*/
-static inline void dentry_iput(struct dentry * dentry)
+static inline void d_iput(struct dentry * dentry)
{
struct inode *inode = dentry->d_inode;
if (inode) {
@@ -84,6 +92,30 @@
spin_unlock(&dcache_lock);
}

+/*
+ * Releases a dentry - unlink from parent, free the inode,
+ * free the entry, and return the parent.
+ * This requires that the LRU list has already been removed.
+ *
+ * Call restrictions: dcache_lock held.
+ * Return state; dcache_lock not held.
+ */
+static inline struct dentry *d_release(struct dentry *dentry)
+{
+ struct dentry *parent;
+
+ list_del_init(&dentry->d_hash);
+ list_del(&dentry->d_child);
+
+ /* drops the lock, at that point nobody can reach this dentry */
+ d_iput(dentry);
+
+ parent = dentry->d_parent;
+ d_free(dentry);
+
+ return parent;
+}
+
/*
* This is dput
*
@@ -115,6 +147,8 @@

void dput(struct dentry *dentry)
{
+ struct dentry *parent;
+
if (!dentry)
return;

@@ -130,31 +164,23 @@
*/
if (dentry->d_op && dentry->d_op->d_delete) {
if (dentry->d_op->d_delete(dentry))
- goto unhash_it;
+ goto kill_it;
}
/* Unreachable? Get rid of it */
- if (list_empty(&dentry->d_hash))
+ if (d_unhashed(dentry))
goto kill_it;
list_add(&dentry->d_lru, &dentry_unused);
dentry_stat.nr_unused++;
spin_unlock(&dcache_lock);
return;

-unhash_it:
- list_del_init(&dentry->d_hash);
+kill_it:
+ parent = d_release(dentry);
+ if (dentry == parent)
+ return;

-kill_it: {
- struct dentry *parent;
- list_del(&dentry->d_child);
- /* drops the lock, at that point nobody can reach this dentry */
- dentry_iput(dentry);
- parent = dentry->d_parent;
- d_free(dentry);
- if (dentry == parent)
- return;
- dentry = parent;
- goto repeat;
- }
+ dentry = parent;
+ goto repeat;
}

/**
@@ -175,7 +201,7 @@
* If it's already been dropped, return OK.
*/
spin_lock(&dcache_lock);
- if (list_empty(&dentry->d_hash)) {
+ if (d_unhashed(dentry)) {
spin_unlock(&dcache_lock);
return 0;
}
@@ -253,7 +279,7 @@
tmp = next;
next = tmp->next;
alias = list_entry(tmp, struct dentry, d_alias);
- if (!list_empty(&alias->d_hash)) {
+ if (!d_unhashed(alias)) {
if (alias->d_flags & DCACHE_DISCONNECTED)
discon_alias = alias;
else {
@@ -302,11 +328,7 @@
{
struct dentry * parent;

- list_del_init(&dentry->d_hash);
- list_del(&dentry->d_child);
- dentry_iput(dentry);
- parent = dentry->d_parent;
- d_free(dentry);
+ parent = d_release(dentry);
if (parent != dentry)
dput(parent);
spin_lock(&dcache_lock);
@@ -589,7 +611,7 @@
* Nasty deadlock avoidance.
*
* ext2_new_block->getblk->GFP->shrink_dcache_memory->prune_dcache->
- * prune_one_dentry->dput->dentry_iput->iput->inode->i_sb->s_op->
+ * prune_one_dentry->dput->d_iput->iput->inode->i_sb->s_op->
* put_inode->ext2_discard_prealloc->ext2_free_blocks->lock_super->
* DEADLOCK.
*
@@ -960,7 +982,7 @@
*/
spin_lock(&dcache_lock);
if (atomic_read(&dentry->d_count) == 1) {
- dentry_iput(dentry);
+ d_iput(dentry);
return;
}
spin_unlock(&dcache_lock);
@@ -982,7 +1004,7 @@
void d_rehash(struct dentry * entry)
{
struct list_head *list = d_hash(entry->d_parent, entry->d_name.hash);
- if (!list_empty(&entry->d_hash)) BUG();
+ if (!d_unhashed(entry)) BUG();
spin_lock(&dcache_lock);
list_add(&entry->d_hash, list);
spin_unlock(&dcache_lock);
@@ -1106,7 +1128,7 @@

*--end = '\0';
buflen--;
- if (!IS_ROOT(dentry) && list_empty(&dentry->d_hash)) {
+ if (!IS_ROOT(dentry) && d_unhashed(dentry)) {
buflen -= 10;
end -= 10;
memcpy(end, " (deleted)", 10);
@@ -1189,7 +1211,7 @@
error = -ENOENT;
/* Has the current directory has been unlinked? */
spin_lock(&dcache_lock);
- if (pwd->d_parent == pwd || !list_empty(&pwd->d_hash)) {
+ if (pwd->d_parent == pwd || !d_unhashed(pwd)) {
unsigned long len;
char * cwd;

-- 
Dan Aloni
da-x@gmx.net
-
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