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Diffstat (limited to 'fs/dcache.c')
-rw-r--r--fs/dcache.c106
1 files changed, 58 insertions, 48 deletions
diff --git a/fs/dcache.c b/fs/dcache.c
index 9791b1e7eee..16a53cc2cc0 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -243,6 +243,7 @@ static void dentry_lru_add(struct dentry *dentry)
static void __dentry_lru_del(struct dentry *dentry)
{
list_del_init(&dentry->d_lru);
+ dentry->d_flags &= ~DCACHE_SHRINK_LIST;
dentry->d_sb->s_nr_dentry_unused--;
dentry_stat.nr_unused--;
}
@@ -276,15 +277,15 @@ static void dentry_lru_prune(struct dentry *dentry)
}
}
-static void dentry_lru_move_tail(struct dentry *dentry)
+static void dentry_lru_move_list(struct dentry *dentry, struct list_head *list)
{
spin_lock(&dcache_lru_lock);
if (list_empty(&dentry->d_lru)) {
- list_add_tail(&dentry->d_lru, &dentry->d_sb->s_dentry_lru);
+ list_add_tail(&dentry->d_lru, list);
dentry->d_sb->s_nr_dentry_unused++;
dentry_stat.nr_unused++;
} else {
- list_move_tail(&dentry->d_lru, &dentry->d_sb->s_dentry_lru);
+ list_move_tail(&dentry->d_lru, list);
}
spin_unlock(&dcache_lru_lock);
}
@@ -770,14 +771,18 @@ static void shrink_dentry_list(struct list_head *list)
}
/**
- * __shrink_dcache_sb - shrink the dentry LRU on a given superblock
- * @sb: superblock to shrink dentry LRU.
- * @count: number of entries to prune
- * @flags: flags to control the dentry processing
+ * prune_dcache_sb - shrink the dcache
+ * @sb: superblock
+ * @count: number of entries to try to free
+ *
+ * Attempt to shrink the superblock dcache LRU by @count entries. This is
+ * done when we need more memory an called from the superblock shrinker
+ * function.
*
- * If flags contains DCACHE_REFERENCED reference dentries will not be pruned.
+ * This function may fail to free any resources if all the dentries are in
+ * use.
*/
-static void __shrink_dcache_sb(struct super_block *sb, int count, int flags)
+void prune_dcache_sb(struct super_block *sb, int count)
{
struct dentry *dentry;
LIST_HEAD(referenced);
@@ -796,18 +801,13 @@ relock:
goto relock;
}
- /*
- * If we are honouring the DCACHE_REFERENCED flag and the
- * dentry has this flag set, don't free it. Clear the flag
- * and put it back on the LRU.
- */
- if (flags & DCACHE_REFERENCED &&
- dentry->d_flags & DCACHE_REFERENCED) {
+ if (dentry->d_flags & DCACHE_REFERENCED) {
dentry->d_flags &= ~DCACHE_REFERENCED;
list_move(&dentry->d_lru, &referenced);
spin_unlock(&dentry->d_lock);
} else {
list_move_tail(&dentry->d_lru, &tmp);
+ dentry->d_flags |= DCACHE_SHRINK_LIST;
spin_unlock(&dentry->d_lock);
if (!--count)
break;
@@ -822,23 +822,6 @@ relock:
}
/**
- * prune_dcache_sb - shrink the dcache
- * @sb: superblock
- * @nr_to_scan: number of entries to try to free
- *
- * Attempt to shrink the superblock dcache LRU by @nr_to_scan entries. This is
- * done when we need more memory an called from the superblock shrinker
- * function.
- *
- * This function may fail to free any resources if all the dentries are in
- * use.
- */
-void prune_dcache_sb(struct super_block *sb, int nr_to_scan)
-{
- __shrink_dcache_sb(sb, nr_to_scan, DCACHE_REFERENCED);
-}
-
-/**
* shrink_dcache_sb - shrink dcache for a superblock
* @sb: superblock
*
@@ -1092,7 +1075,7 @@ EXPORT_SYMBOL(have_submounts);
* drop the lock and return early due to latency
* constraints.
*/
-static int select_parent(struct dentry * parent)
+static int select_parent(struct dentry *parent, struct list_head *dispose)
{
struct dentry *this_parent;
struct list_head *next;
@@ -1114,17 +1097,21 @@ resume:
spin_lock_nested(&dentry->d_lock, DENTRY_D_LOCK_NESTED);
- /*
- * move only zero ref count dentries to the end
- * of the unused list for prune_dcache
+ /*
+ * move only zero ref count dentries to the dispose list.
+ *
+ * Those which are presently on the shrink list, being processed
+ * by shrink_dentry_list(), shouldn't be moved. Otherwise the
+ * loop in shrink_dcache_parent() might not make any progress
+ * and loop forever.
*/
- if (!dentry->d_count) {
- dentry_lru_move_tail(dentry);
- found++;
- } else {
+ if (dentry->d_count) {
dentry_lru_del(dentry);
+ } else if (!(dentry->d_flags & DCACHE_SHRINK_LIST)) {
+ dentry_lru_move_list(dentry, dispose);
+ dentry->d_flags |= DCACHE_SHRINK_LIST;
+ found++;
}
-
/*
* We can return to the caller if we have found some (this
* ensures forward progress). We'll be coming back to find
@@ -1181,14 +1168,13 @@ rename_retry:
*
* Prune the dcache to remove unused children of the parent dentry.
*/
-
void shrink_dcache_parent(struct dentry * parent)
{
- struct super_block *sb = parent->d_sb;
+ LIST_HEAD(dispose);
int found;
- while ((found = select_parent(parent)) != 0)
- __shrink_dcache_sb(sb, found, 0);
+ while ((found = select_parent(parent, &dispose)) != 0)
+ shrink_dentry_list(&dispose);
}
EXPORT_SYMBOL(shrink_dcache_parent);
@@ -1461,6 +1447,23 @@ struct dentry * d_alloc_root(struct inode * root_inode)
}
EXPORT_SYMBOL(d_alloc_root);
+struct dentry *d_make_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);
+ else
+ iput(root_inode);
+ }
+ return res;
+}
+EXPORT_SYMBOL(d_make_root);
+
static struct dentry * __d_find_any_alias(struct inode *inode)
{
struct dentry *alias;
@@ -1472,7 +1475,14 @@ static struct dentry * __d_find_any_alias(struct inode *inode)
return alias;
}
-static struct dentry * d_find_any_alias(struct inode *inode)
+/**
+ * d_find_any_alias - find any alias for a given inode
+ * @inode: inode to find an alias for
+ *
+ * If any aliases exist for the given inode, take and return a
+ * reference for one of them. If no aliases exist, return %NULL.
+ */
+struct dentry *d_find_any_alias(struct inode *inode)
{
struct dentry *de;
@@ -1481,7 +1491,7 @@ static struct dentry * d_find_any_alias(struct inode *inode)
spin_unlock(&inode->i_lock);
return de;
}
-
+EXPORT_SYMBOL(d_find_any_alias);
/**
* d_obtain_alias - find or allocate a dentry for a given inode