kmem_cache_free(dentry_cache, dentry);
}
+static inline int dname_external(const struct dentry *dentry)
+{
+ return dentry->d_name.name != dentry->d_iname;
+}
+
static void dentry_free(struct dentry *dentry)
{
if (unlikely(dname_external(dentry))) {
* inform the fs via d_prune that this dentry is about to be
* unhashed and destroyed.
*/
- if ((dentry->d_flags & DCACHE_OP_PRUNE) && !d_unhashed(dentry))
+ if (dentry->d_flags & DCACHE_OP_PRUNE)
dentry->d_op->d_prune(dentry);
if (dentry->d_flags & DCACHE_LRU_LIST) {
}
EXPORT_SYMBOL(dput);
-/**
- * d_invalidate - invalidate a dentry
- * @dentry: dentry to invalidate
- *
- * Try to invalidate the dentry if it turns out to be
- * possible. If there are other dentries that can be
- * reached through this one we can't delete it and we
- * return -EBUSY. On success we return 0.
- *
- * no dcache lock.
- */
-
-int d_invalidate(struct dentry * dentry)
-{
- /*
- * If it's already been dropped, return OK.
- */
- spin_lock(&dentry->d_lock);
- if (d_unhashed(dentry)) {
- spin_unlock(&dentry->d_lock);
- return 0;
- }
- /*
- * Check whether to do a partial shrink_dcache
- * to get rid of unused child entries.
- */
- if (!list_empty(&dentry->d_subdirs)) {
- spin_unlock(&dentry->d_lock);
- shrink_dcache_parent(dentry);
- spin_lock(&dentry->d_lock);
- }
-
- /*
- * Somebody else still using it?
- *
- * If it's a directory, we can't drop it
- * for fear of somebody re-populating it
- * with children (even though dropping it
- * would make it unreachable from the root,
- * we might still populate it if it was a
- * working directory or similar).
- * We also need to leave mountpoints alone,
- * directory or not.
- */
- if (dentry->d_lockref.count > 1 && dentry->d_inode) {
- if (S_ISDIR(dentry->d_inode->i_mode) || d_mountpoint(dentry)) {
- spin_unlock(&dentry->d_lock);
- return -EBUSY;
- }
- }
-
- __d_drop(dentry);
- spin_unlock(&dentry->d_lock);
- return 0;
-}
-EXPORT_SYMBOL(d_invalidate);
/* This must be called with d_lock held */
static inline void __dget_dlock(struct dentry *dentry)
hlist_for_each_entry(dentry, &inode->i_dentry, d_alias) {
spin_lock(&dentry->d_lock);
if (!dentry->d_lockref.count) {
- /*
- * inform the fs via d_prune that this dentry
- * is about to be unhashed and destroyed.
- */
- if ((dentry->d_flags & DCACHE_OP_PRUNE) &&
- !d_unhashed(dentry))
- dentry->d_op->d_prune(dentry);
-
- __dget_dlock(dentry);
- __d_drop(dentry);
- spin_unlock(&dentry->d_lock);
- spin_unlock(&inode->i_lock);
- dput(dentry);
- goto restart;
+ struct dentry *parent = lock_parent(dentry);
+ if (likely(!dentry->d_lockref.count)) {
+ __dentry_kill(dentry);
+ goto restart;
+ }
+ if (parent)
+ spin_unlock(&parent->d_lock);
}
spin_unlock(&dentry->d_lock);
}
* reachable (e.g. NFS can unhash a directory dentry and then the complete
* subtree can become unreachable).
*
- * Only one of check_submounts_and_drop() and d_set_mounted() must succeed. For
+ * Only one of d_invalidate() and d_set_mounted() must succeed. For
* this reason take rename_lock and d_lock on dentry and ancestors.
*/
int d_set_mounted(struct dentry *dentry)
int ret = -ENOENT;
write_seqlock(&rename_lock);
for (p = dentry->d_parent; !IS_ROOT(p); p = p->d_parent) {
- /* Need exclusion wrt. check_submounts_and_drop() */
+ /* Need exclusion wrt. d_invalidate() */
spin_lock(&p->d_lock);
if (unlikely(d_unhashed(p))) {
spin_unlock(&p->d_lock);
}
}
-static enum d_walk_ret check_and_collect(void *_data, struct dentry *dentry)
+struct detach_data {
+ struct select_data select;
+ struct dentry *mountpoint;
+};
+static enum d_walk_ret detach_and_collect(void *_data, struct dentry *dentry)
{
- struct select_data *data = _data;
+ struct detach_data *data = _data;
if (d_mountpoint(dentry)) {
- data->found = -EBUSY;
+ __dget_dlock(dentry);
+ data->mountpoint = dentry;
return D_WALK_QUIT;
}
- return select_collect(_data, dentry);
+ return select_collect(&data->select, dentry);
}
static void check_and_drop(void *_data)
{
- struct select_data *data = _data;
+ struct detach_data *data = _data;
- if (d_mountpoint(data->start))
- data->found = -EBUSY;
- if (!data->found)
- __d_drop(data->start);
+ if (!data->mountpoint && !data->select.found)
+ __d_drop(data->select.start);
}
/**
- * check_submounts_and_drop - prune dcache, check for submounts and drop
+ * d_invalidate - detach submounts, prune dcache, and drop
+ * @dentry: dentry to invalidate (aka detach, prune and drop)
*
- * All done as a single atomic operation relative to has_unlinked_ancestor().
- * Returns 0 if successfully unhashed @parent. If there were submounts then
- * return -EBUSY.
+ * no dcache lock.
*
- * @dentry: dentry to prune and drop
+ * The final d_drop is done as an atomic operation relative to
+ * rename_lock ensuring there are no races with d_set_mounted. This
+ * ensures there are no unhashed dentries on the path to a mountpoint.
*/
-int check_submounts_and_drop(struct dentry *dentry)
+void d_invalidate(struct dentry *dentry)
{
- int ret = 0;
+ /*
+ * If it's already been dropped, return OK.
+ */
+ spin_lock(&dentry->d_lock);
+ if (d_unhashed(dentry)) {
+ spin_unlock(&dentry->d_lock);
+ return;
+ }
+ spin_unlock(&dentry->d_lock);
/* Negative dentries can be dropped without further checks */
if (!dentry->d_inode) {
d_drop(dentry);
- goto out;
+ return;
}
for (;;) {
- struct select_data data;
+ struct detach_data data;
- INIT_LIST_HEAD(&data.dispose);
- data.start = dentry;
- data.found = 0;
+ data.mountpoint = NULL;
+ INIT_LIST_HEAD(&data.select.dispose);
+ data.select.start = dentry;
+ data.select.found = 0;
- d_walk(dentry, &data, check_and_collect, check_and_drop);
- ret = data.found;
+ d_walk(dentry, &data, detach_and_collect, check_and_drop);
- if (!list_empty(&data.dispose))
- shrink_dentry_list(&data.dispose);
+ if (data.select.found)
+ shrink_dentry_list(&data.select.dispose);
- if (ret <= 0)
+ if (data.mountpoint) {
+ detach_mounts(data.mountpoint);
+ dput(data.mountpoint);
+ }
+
+ if (!data.mountpoint && !data.select.found)
break;
cond_resched();
}
-
-out:
- return ret;
}
-EXPORT_SYMBOL(check_submounts_and_drop);
+EXPORT_SYMBOL(d_invalidate);
/**
* __d_alloc - allocate a dcache entry
struct dentry *dentry;
unsigned seq;
- do {
- seq = read_seqbegin(&rename_lock);
- dentry = __d_lookup(parent, name);
- if (dentry)
+ do {
+ seq = read_seqbegin(&rename_lock);
+ dentry = __d_lookup(parent, name);
+ if (dentry)
break;
} while (read_seqretry(&rename_lock, seq));
return dentry;
goto out_err;
m2 = &alias->d_parent->d_inode->i_mutex;
out_unalias:
- if (likely(!d_mountpoint(alias))) {
- __d_move(alias, dentry, false);
- ret = alias;
- }
+ __d_move(alias, dentry, false);
+ ret = alias;
out_err:
spin_unlock(&inode->i_lock);
if (m2)
projects / firefly-linux-kernel-4.4.55.git / blobdiff