#include <linux/prefetch.h>
#include <linux/ratelimit.h>
#include "internal.h"
+#include "mount.h"
/*
* Usage:
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--;
}
}
}
-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);
}
}
/**
- * __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);
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;
shrink_dentry_list(&tmp);
}
-/**
- * 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
* 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;
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
*
* 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);
}
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;
{
struct dentry *dentry = path->dentry;
struct vfsmount *vfsmnt = path->mnt;
+ struct mount *mnt = real_mount(vfsmnt);
bool slash = false;
int error = 0;
if (dentry == vfsmnt->mnt_root || IS_ROOT(dentry)) {
/* Global root? */
- if (vfsmnt->mnt_parent == vfsmnt) {
+ if (!mnt_has_parent(mnt))
goto global_root;
- }
- dentry = vfsmnt->mnt_mountpoint;
- vfsmnt = vfsmnt->mnt_parent;
+ dentry = mnt->mnt_mountpoint;
+ mnt = mnt->mnt_parent;
+ vfsmnt = &mnt->mnt;
continue;
}
parent = dentry->d_parent;
if (!slash)
error = prepend(buffer, buflen, "/", 1);
if (!error)
- error = vfsmnt->mnt_ns ? 1 : 2;
+ error = real_mount(vfsmnt)->mnt_ns ? 1 : 2;
goto out;
}
return result;
}
-int path_is_under(struct path *path1, struct path *path2)
-{
- struct vfsmount *mnt = path1->mnt;
- struct dentry *dentry = path1->dentry;
- int res;
-
- br_read_lock(vfsmount_lock);
- if (mnt != path2->mnt) {
- for (;;) {
- if (mnt->mnt_parent == mnt) {
- br_read_unlock(vfsmount_lock);
- return 0;
- }
- if (mnt->mnt_parent == path2->mnt)
- break;
- mnt = mnt->mnt_parent;
- }
- dentry = mnt->mnt_mountpoint;
- }
- res = is_subdir(dentry, path2->dentry);
- br_read_unlock(vfsmount_lock);
- return res;
-}
-EXPORT_SYMBOL(path_is_under);
-
void d_genocide(struct dentry *root)
{
struct dentry *this_parent;
git.openpandora.org / pandora-kernel.git / blobdiff