/*
* Usage:
* dcache->d_inode->i_lock protects:
- * - i_dentry, d_alias, d_inode of aliases
+ * - i_dentry, d_u.d_alias, d_inode of aliases
* dcache_hash_bucket lock protects:
* - the dcache hash table
* s_anon bl list spinlock protects:
* - d_unhashed()
* - d_parent and d_subdirs
* - childrens' d_child and d_parent
- * - d_alias, d_inode
+ * - d_u.d_alias, d_inode
*
* Ordering:
* dentry->d_inode->i_lock
* This hash-function tries to avoid losing too many bits of hash
* information, yet avoid using a prime hash-size or similar.
*/
-#define D_HASHBITS d_hash_shift
-#define D_HASHMASK d_hash_mask
static unsigned int d_hash_mask __read_mostly;
static unsigned int d_hash_shift __read_mostly;
unsigned int hash)
{
hash += (unsigned long) parent / L1_CACHE_BYTES;
- hash = hash + (hash >> D_HASHBITS);
- return dentry_hashtable + (hash & D_HASHMASK);
+ return dentry_hashtable + hash_32(hash, d_hash_shift);
}
/* Statistics gathering. */
{
struct dentry *dentry = container_of(head, struct dentry, d_u.d_rcu);
- WARN_ON(!hlist_unhashed(&dentry->d_alias));
if (dname_external(dentry))
kfree(dentry->d_name.name);
kmem_cache_free(dentry_cache, dentry);
*/
static void d_free(struct dentry *dentry)
{
+ WARN_ON(!hlist_unhashed(&dentry->d_u.d_alias));
BUG_ON(dentry->d_count);
this_cpu_dec(nr_dentry);
if (dentry->d_op && dentry->d_op->d_release)
call_rcu(&dentry->d_u.d_rcu, __d_free);
}
+void take_dentry_name_snapshot(struct name_snapshot *name, struct dentry *dentry)
+{
+ spin_lock(&dentry->d_lock);
+ if (unlikely(dname_external(dentry))) {
+ u32 len;
+ char *p;
+ for (;;) {
+ len = dentry->d_name.len;
+ spin_unlock(&dentry->d_lock);
+ p = kmalloc(len + 1, GFP_KERNEL | __GFP_NOFAIL);
+ spin_lock(&dentry->d_lock);
+ if (dentry->d_name.len <= len)
+ break;
+ kfree(p);
+ }
+ memcpy(p, dentry->d_name.name, dentry->d_name.len + 1);
+ spin_unlock(&dentry->d_lock);
+ name->name = p;
+ } else {
+ memcpy(name->inline_name, dentry->d_iname, DNAME_INLINE_LEN);
+ spin_unlock(&dentry->d_lock);
+ name->name = name->inline_name;
+ }
+}
+EXPORT_SYMBOL(take_dentry_name_snapshot);
+ void release_dentry_name_snapshot(struct name_snapshot *name)
+{
+ if (unlikely(name->name != name->inline_name))
+ kfree(name->name);
+}
+EXPORT_SYMBOL(release_dentry_name_snapshot);
+
/**
* dentry_rcuwalk_barrier - invalidate in-progress rcu-walk lookups
* @dentry: the target dentry
struct inode *inode = dentry->d_inode;
if (inode) {
dentry->d_inode = NULL;
- hlist_del_init(&dentry->d_alias);
+ hlist_del_init(&dentry->d_u.d_alias);
spin_unlock(&dentry->d_lock);
spin_unlock(&inode->i_lock);
if (!inode->i_nlink)
{
struct inode *inode = dentry->d_inode;
dentry->d_inode = NULL;
- hlist_del_init(&dentry->d_alias);
+ hlist_del_init(&dentry->d_u.d_alias);
dentry_rcuwalk_barrier(dentry);
spin_unlock(&dentry->d_lock);
spin_unlock(&inode->i_lock);
__releases(parent->d_lock)
__releases(dentry->d_inode->i_lock)
{
- list_del(&dentry->d_u.d_child);
+ __list_del_entry(&dentry->d_child);
/*
- * Inform try_to_ascend() that we are no longer attached to the
+ * Inform ascending readers that we are no longer attached to the
* dentry tree
*/
dentry->d_flags |= DCACHE_DENTRY_KILLED;
return;
}
+ if (unlikely(dentry->d_flags & DCACHE_DISCONNECTED))
+ goto kill_it;
+
if (dentry->d_flags & DCACHE_OP_DELETE) {
if (dentry->d_op->d_delete(dentry))
goto kill_it;
again:
discon_alias = NULL;
- hlist_for_each_entry(alias, &inode->i_dentry, d_alias) {
+ hlist_for_each_entry(alias, &inode->i_dentry, d_u.d_alias) {
spin_lock(&alias->d_lock);
if (S_ISDIR(inode->i_mode) || !d_unhashed(alias)) {
if (IS_ROOT(alias) &&
struct dentry *dentry;
restart:
spin_lock(&inode->i_lock);
- hlist_for_each_entry(dentry, &inode->i_dentry, d_alias) {
+ hlist_for_each_entry(dentry, &inode->i_dentry, d_u.d_alias) {
spin_lock(&dentry->d_lock);
if (!dentry->d_count) {
__dget_dlock(dentry);
/* descend to the first leaf in the current subtree */
while (!list_empty(&dentry->d_subdirs))
dentry = list_entry(dentry->d_subdirs.next,
- struct dentry, d_u.d_child);
+ struct dentry, d_child);
/* consume the dentries from this leaf up through its parents
* until we find one with children or run out altogether */
if (IS_ROOT(dentry)) {
parent = NULL;
- list_del(&dentry->d_u.d_child);
+ list_del(&dentry->d_child);
} else {
parent = dentry->d_parent;
parent->d_count--;
- list_del(&dentry->d_u.d_child);
+ list_del(&dentry->d_child);
}
inode = dentry->d_inode;
if (inode) {
dentry->d_inode = NULL;
- hlist_del_init(&dentry->d_alias);
+ hlist_del_init(&dentry->d_u.d_alias);
if (dentry->d_op && dentry->d_op->d_iput)
dentry->d_op->d_iput(dentry, inode);
else
} while (list_empty(&dentry->d_subdirs));
dentry = list_entry(dentry->d_subdirs.next,
- struct dentry, d_u.d_child);
+ struct dentry, d_child);
}
}
}
}
-/*
- * This tries to ascend one level of parenthood, but
- * we can race with renaming, so we need to re-check
- * the parenthood after dropping the lock and check
- * that the sequence number still matches.
- */
-static struct dentry *try_to_ascend(struct dentry *old, int locked, unsigned seq)
-{
- struct dentry *new = old->d_parent;
-
- rcu_read_lock();
- spin_unlock(&old->d_lock);
- spin_lock(&new->d_lock);
-
- /*
- * might go back up the wrong parent if we have had a rename
- * or deletion
- */
- if (new != old->d_parent ||
- (old->d_flags & DCACHE_DENTRY_KILLED) ||
- (!locked && read_seqretry(&rename_lock, seq))) {
- spin_unlock(&new->d_lock);
- new = NULL;
- }
- rcu_read_unlock();
- return new;
-}
-
-
/*
* Search for at least 1 mount point in the dentry's subdirs.
* We descend to the next level whenever the d_subdirs
resume:
while (next != &this_parent->d_subdirs) {
struct list_head *tmp = next;
- struct dentry *dentry = list_entry(tmp, struct dentry, d_u.d_child);
+ struct dentry *dentry = list_entry(tmp, struct dentry, d_child);
next = tmp->next;
spin_lock_nested(&dentry->d_lock, DENTRY_D_LOCK_NESTED);
/*
* All done at this level ... ascend and resume the search.
*/
+ rcu_read_lock();
+ascend:
if (this_parent != parent) {
struct dentry *child = this_parent;
- this_parent = try_to_ascend(this_parent, locked, seq);
- if (!this_parent)
+ this_parent = child->d_parent;
+
+ spin_unlock(&child->d_lock);
+ spin_lock(&this_parent->d_lock);
+
+ /* might go back up the wrong parent if we have had a rename. */
+ if (!locked && read_seqretry(&rename_lock, seq))
goto rename_retry;
- next = child->d_u.d_child.next;
+ /* go into the first sibling still alive */
+ do {
+ next = child->d_child.next;
+ if (next == &this_parent->d_subdirs)
+ goto ascend;
+ child = list_entry(next, struct dentry, d_child);
+ } while (unlikely(child->d_flags & DCACHE_DENTRY_KILLED));
+ rcu_read_unlock();
goto resume;
}
- spin_unlock(&this_parent->d_lock);
if (!locked && read_seqretry(&rename_lock, seq))
goto rename_retry;
+ spin_unlock(&this_parent->d_lock);
+ rcu_read_unlock();
if (locked)
write_sequnlock(&rename_lock);
return 0; /* No mount points found in tree */
positive:
if (!locked && read_seqretry(&rename_lock, seq))
- goto rename_retry;
+ goto rename_retry_unlocked;
if (locked)
write_sequnlock(&rename_lock);
return 1;
rename_retry:
+ spin_unlock(&this_parent->d_lock);
+ rcu_read_unlock();
if (locked)
goto again;
+rename_retry_unlocked:
locked = 1;
write_seqlock(&rename_lock);
goto again;
resume:
while (next != &this_parent->d_subdirs) {
struct list_head *tmp = next;
- struct dentry *dentry = list_entry(tmp, struct dentry, d_u.d_child);
+ struct dentry *dentry = list_entry(tmp, struct dentry, d_child);
next = tmp->next;
spin_lock_nested(&dentry->d_lock, DENTRY_D_LOCK_NESTED);
*/
if (found && need_resched()) {
spin_unlock(&dentry->d_lock);
+ rcu_read_lock();
goto out;
}
/*
* All done at this level ... ascend and resume the search.
*/
+ rcu_read_lock();
+ascend:
if (this_parent != parent) {
struct dentry *child = this_parent;
- this_parent = try_to_ascend(this_parent, locked, seq);
- if (!this_parent)
+ this_parent = child->d_parent;
+
+ spin_unlock(&child->d_lock);
+ spin_lock(&this_parent->d_lock);
+
+ /* might go back up the wrong parent if we have had a rename. */
+ if (!locked && read_seqretry(&rename_lock, seq))
goto rename_retry;
- next = child->d_u.d_child.next;
+ /* go into the first sibling still alive */
+ do {
+ next = child->d_child.next;
+ if (next == &this_parent->d_subdirs)
+ goto ascend;
+ child = list_entry(next, struct dentry, d_child);
+ } while (unlikely(child->d_flags & DCACHE_DENTRY_KILLED));
+ rcu_read_unlock();
goto resume;
}
out:
- spin_unlock(&this_parent->d_lock);
if (!locked && read_seqretry(&rename_lock, seq))
goto rename_retry;
+ spin_unlock(&this_parent->d_lock);
+ rcu_read_unlock();
if (locked)
write_sequnlock(&rename_lock);
return found;
rename_retry:
+ spin_unlock(&this_parent->d_lock);
+ rcu_read_unlock();
if (found)
return found;
if (locked)
INIT_HLIST_BL_NODE(&dentry->d_hash);
INIT_LIST_HEAD(&dentry->d_lru);
INIT_LIST_HEAD(&dentry->d_subdirs);
- INIT_HLIST_NODE(&dentry->d_alias);
- INIT_LIST_HEAD(&dentry->d_u.d_child);
+ INIT_HLIST_NODE(&dentry->d_u.d_alias);
+ INIT_LIST_HEAD(&dentry->d_child);
d_set_d_op(dentry, dentry->d_sb->s_d_op);
this_cpu_inc(nr_dentry);
struct dentry *dentry = __d_alloc(parent->d_sb, name);
if (!dentry)
return NULL;
-
+ dentry->d_flags |= DCACHE_RCUACCESS;
spin_lock(&parent->d_lock);
/*
* don't need child lock because it is not subject
*/
__dget_dlock(parent);
dentry->d_parent = parent;
- list_add(&dentry->d_u.d_child, &parent->d_subdirs);
+ list_add(&dentry->d_child, &parent->d_subdirs);
spin_unlock(&parent->d_lock);
return dentry;
if (inode) {
if (unlikely(IS_AUTOMOUNT(inode)))
dentry->d_flags |= DCACHE_NEED_AUTOMOUNT;
- hlist_add_head(&dentry->d_alias, &inode->i_dentry);
+ hlist_add_head(&dentry->d_u.d_alias, &inode->i_dentry);
}
dentry->d_inode = inode;
dentry_rcuwalk_barrier(dentry);
void d_instantiate(struct dentry *entry, struct inode * inode)
{
- BUG_ON(!hlist_unhashed(&entry->d_alias));
+ BUG_ON(!hlist_unhashed(&entry->d_u.d_alias));
if (inode)
spin_lock(&inode->i_lock);
__d_instantiate(entry, inode);
return NULL;
}
- hlist_for_each_entry(alias, &inode->i_dentry, d_alias) {
+ hlist_for_each_entry(alias, &inode->i_dentry, d_u.d_alias) {
/*
* Don't need alias->d_lock here, because aliases with
* d_parent == entry->d_parent are not subject to name or
{
struct dentry *result;
- BUG_ON(!hlist_unhashed(&entry->d_alias));
+ BUG_ON(!hlist_unhashed(&entry->d_u.d_alias));
if (inode)
spin_lock(&inode->i_lock);
if (hlist_empty(&inode->i_dentry))
return NULL;
- alias = hlist_entry(inode->i_dentry.first, struct dentry, d_alias);
+ alias = hlist_entry(inode->i_dentry.first, struct dentry, d_u.d_alias);
__dget(alias);
return alias;
}
spin_lock(&tmp->d_lock);
tmp->d_inode = inode;
tmp->d_flags |= DCACHE_DISCONNECTED;
- hlist_add_head(&tmp->d_alias, &inode->i_dentry);
+ hlist_add_head(&tmp->d_u.d_alias, &inode->i_dentry);
hlist_bl_lock(&tmp->d_sb->s_anon);
hlist_bl_add_head(&tmp->d_hash, &tmp->d_sb->s_anon);
hlist_bl_unlock(&tmp->d_sb->s_anon);
struct dentry *child;
spin_lock(&dparent->d_lock);
- list_for_each_entry(child, &dparent->d_subdirs, d_u.d_child) {
+ list_for_each_entry(child, &dparent->d_subdirs, d_child) {
if (dentry == child) {
spin_lock_nested(&dentry->d_lock, DENTRY_D_LOCK_NESTED);
__dget_dlock(dentry);
{
BUG_ON(!d_unhashed(entry));
hlist_bl_lock(b);
- entry->d_flags |= DCACHE_RCUACCESS;
hlist_bl_add_head_rcu(&entry->d_hash, b);
hlist_bl_unlock(b);
}
/* Unhash the target: dput() will then get rid of it */
__d_drop(target);
- list_del(&dentry->d_u.d_child);
- list_del(&target->d_u.d_child);
+ list_del(&dentry->d_child);
+ list_del(&target->d_child);
/* Switch the names.. */
switch_names(dentry, target);
/* ... and switch the parents */
if (IS_ROOT(dentry)) {
+ dentry->d_flags |= DCACHE_RCUACCESS;
dentry->d_parent = target->d_parent;
target->d_parent = target;
- INIT_LIST_HEAD(&target->d_u.d_child);
+ INIT_LIST_HEAD(&target->d_child);
} else {
swap(dentry->d_parent, target->d_parent);
/* And add them back to the (new) parent lists */
- list_add(&target->d_u.d_child, &target->d_parent->d_subdirs);
+ list_add(&target->d_child, &target->d_parent->d_subdirs);
}
- list_add(&dentry->d_u.d_child, &dentry->d_parent->d_subdirs);
+ list_add(&dentry->d_child, &dentry->d_parent->d_subdirs);
write_seqcount_end(&target->d_seq);
write_seqcount_end(&dentry->d_seq);
switch_names(dentry, anon);
swap(dentry->d_name.hash, anon->d_name.hash);
+ dentry->d_flags |= DCACHE_RCUACCESS;
dentry->d_parent = dentry;
- list_del_init(&dentry->d_u.d_child);
+ list_del_init(&dentry->d_child);
anon->d_parent = dparent;
- list_move(&anon->d_u.d_child, &dparent->d_subdirs);
+ if (likely(!d_unhashed(anon))) {
+ hlist_bl_lock(&anon->d_sb->s_anon);
+ __hlist_bl_del(&anon->d_hash);
+ anon->d_hash.pprev = NULL;
+ hlist_bl_unlock(&anon->d_sb->s_anon);
+ }
+ list_move(&anon->d_child, &dparent->d_subdirs);
write_seqcount_end(&dentry->d_seq);
write_seqcount_end(&anon->d_seq);
* could splice into our tree? */
__d_materialise_dentry(dentry, alias);
write_sequnlock(&rename_lock);
- __d_drop(alias);
goto found;
} else {
/* Nope, but we must(!) avoid directory
struct dentry *dentry = path->dentry;
struct vfsmount *vfsmnt = path->mnt;
struct mount *mnt = real_mount(vfsmnt);
+ char *orig_buffer = *buffer;
+ int orig_len = *buflen;
bool slash = false;
int error = 0;
struct dentry * parent;
if (dentry == vfsmnt->mnt_root || IS_ROOT(dentry)) {
+ /* Escaped? */
+ if (dentry != vfsmnt->mnt_root) {
+ *buffer = orig_buffer;
+ *buflen = orig_len;
+ slash = false;
+ error = 3;
+ goto global_root;
+ }
/* Global root? */
if (!mnt_has_parent(mnt))
goto global_root;
return error;
global_root:
- /*
- * Filesystems needing to implement special "root names"
- * should do so with ->d_dname()
- */
- if (IS_ROOT(dentry) &&
- (dentry->d_name.len != 1 || dentry->d_name.name[0] != '/')) {
- WARN(1, "Root dentry has weird name <%.*s>\n",
- (int) dentry->d_name.len, dentry->d_name.name);
- }
if (!slash)
error = prepend(buffer, buflen, "/", 1);
if (!error)
* thus don't need to be hashed. They also don't need a name until a
* user wants to identify the object in /proc/pid/fd/. The little hack
* below allows us to generate a name for these objects on demand:
+ *
+ * Some pseudo inodes are mountable. When they are mounted
+ * path->dentry == path->mnt->mnt_root. In that case don't call d_dname
+ * and instead have d_path return the mounted path.
*/
- if (path->dentry->d_op && path->dentry->d_op->d_dname)
+ if (path->dentry->d_op && path->dentry->d_op->d_dname &&
+ (!IS_ROOT(path->dentry) || path->dentry != path->mnt->mnt_root))
return path->dentry->d_op->d_dname(path->dentry, buf, buflen);
get_fs_root(current->fs, &root);
return memcpy(buffer, temp, sz);
}
+char *simple_dname(struct dentry *dentry, char *buffer, int buflen)
+{
+ char *end = buffer + buflen;
+ /* these dentries are never renamed, so d_lock is not needed */
+ if (prepend(&end, &buflen, " (deleted)", 11) ||
+ prepend_name(&end, &buflen, &dentry->d_name) ||
+ prepend(&end, &buflen, "/", 1))
+ end = ERR_PTR(-ENAMETOOLONG);
+ return end;
+}
+
/*
* Write full pathname from the root of the filesystem into the buffer.
*/
resume:
while (next != &this_parent->d_subdirs) {
struct list_head *tmp = next;
- struct dentry *dentry = list_entry(tmp, struct dentry, d_u.d_child);
+ struct dentry *dentry = list_entry(tmp, struct dentry, d_child);
next = tmp->next;
spin_lock_nested(&dentry->d_lock, DENTRY_D_LOCK_NESTED);
}
spin_unlock(&dentry->d_lock);
}
+ rcu_read_lock();
+ascend:
if (this_parent != root) {
struct dentry *child = this_parent;
if (!(this_parent->d_flags & DCACHE_GENOCIDE)) {
this_parent->d_flags |= DCACHE_GENOCIDE;
this_parent->d_count--;
}
- this_parent = try_to_ascend(this_parent, locked, seq);
- if (!this_parent)
+ this_parent = child->d_parent;
+
+ spin_unlock(&child->d_lock);
+ spin_lock(&this_parent->d_lock);
+
+ /* might go back up the wrong parent if we have had a rename. */
+ if (!locked && read_seqretry(&rename_lock, seq))
goto rename_retry;
- next = child->d_u.d_child.next;
+ /* go into the first sibling still alive */
+ do {
+ next = child->d_child.next;
+ if (next == &this_parent->d_subdirs)
+ goto ascend;
+ child = list_entry(next, struct dentry, d_child);
+ } while (unlikely(child->d_flags & DCACHE_DENTRY_KILLED));
+ rcu_read_unlock();
goto resume;
}
- spin_unlock(&this_parent->d_lock);
if (!locked && read_seqretry(&rename_lock, seq))
goto rename_retry;
+ spin_unlock(&this_parent->d_lock);
+ rcu_read_unlock();
if (locked)
write_sequnlock(&rename_lock);
return;
rename_retry:
+ spin_unlock(&this_parent->d_lock);
+ rcu_read_unlock();
if (locked)
goto again;
locked = 1;
goto again;
}
+void d_tmpfile(struct dentry *dentry, struct inode *inode)
+{
+ inode_dec_link_count(inode);
+ BUG_ON(dentry->d_name.name != dentry->d_iname ||
+ !hlist_unhashed(&dentry->d_u.d_alias) ||
+ !d_unlinked(dentry));
+ spin_lock(&dentry->d_parent->d_lock);
+ spin_lock_nested(&dentry->d_lock, DENTRY_D_LOCK_NESTED);
+ dentry->d_name.len = sprintf(dentry->d_iname, "#%llu",
+ (unsigned long long)inode->i_ino);
+ spin_unlock(&dentry->d_lock);
+ spin_unlock(&dentry->d_parent->d_lock);
+ d_instantiate(dentry, inode);
+}
+EXPORT_SYMBOL(d_tmpfile);
+
/**
* find_inode_number - check for dentry with name
* @dir: directory to check
projects / GitHub / LineageOS / android_kernel_samsung_universal7580.git / blobdiff