ovl: constant d_ino for non-merge dirs
Impure directories are ones which contain objects with origins (i.e. those
that have been copied up). These are relevant to readdir operation only
because of the d_ino field, no other transformation is necessary. Also a
directory can become impure between two getdents(2) calls.
This patch creates a cache for impure directories. Unlike the cache for
merged directories, this one only contains entries with origin and is not
refcounted but has a its lifetime tied to that of the dentry.
Similarly to the merged cache, the impure cache is invalidated based on a
version number. This version number is incremented when an entry with
origin is added or removed from the directory.
If the cache is empty, then the impure xattr is removed from the directory.
This patch also fixes up handling of d_ino for the ".." entry if the parent
directory is merged.
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
diff --git a/fs/overlayfs/dir.c b/fs/overlayfs/dir.c
index 48b70e6..9cb0c80e 100644
--- a/fs/overlayfs/dir.c
+++ b/fs/overlayfs/dir.c
@@ -155,7 +155,7 @@
static void ovl_instantiate(struct dentry *dentry, struct inode *inode,
struct dentry *newdentry, bool hardlink)
{
- ovl_dentry_version_inc(dentry->d_parent);
+ ovl_dentry_version_inc(dentry->d_parent, false);
ovl_dentry_set_upper_alias(dentry);
if (!hardlink) {
ovl_inode_update(inode, newdentry);
@@ -692,7 +692,7 @@
if (flags)
ovl_cleanup(wdir, upper);
- ovl_dentry_version_inc(dentry->d_parent);
+ ovl_dentry_version_inc(dentry->d_parent, true);
out_d_drop:
d_drop(dentry);
dput(whiteout);
@@ -742,7 +742,7 @@
err = vfs_rmdir(dir, upper);
else
err = vfs_unlink(dir, upper, NULL);
- ovl_dentry_version_inc(dentry->d_parent);
+ ovl_dentry_version_inc(dentry->d_parent, ovl_type_origin(dentry));
/*
* Keeping this dentry hashed would mean having to release
@@ -1089,8 +1089,9 @@
drop_nlink(d_inode(new));
}
- ovl_dentry_version_inc(old->d_parent);
- ovl_dentry_version_inc(new->d_parent);
+ ovl_dentry_version_inc(old->d_parent,
+ !overwrite && ovl_type_origin(new));
+ ovl_dentry_version_inc(new->d_parent, ovl_type_origin(old));
out_dput:
dput(newdentry);
diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h
index e927a62..d4e8c1a 100644
--- a/fs/overlayfs/overlayfs.h
+++ b/fs/overlayfs/overlayfs.h
@@ -204,8 +204,8 @@
struct inode *ovl_inode_upper(struct inode *inode);
struct inode *ovl_inode_lower(struct inode *inode);
struct inode *ovl_inode_real(struct inode *inode);
-struct ovl_dir_cache *ovl_dir_cache(struct dentry *dentry);
-void ovl_set_dir_cache(struct dentry *dentry, struct ovl_dir_cache *cache);
+struct ovl_dir_cache *ovl_dir_cache(struct inode *inode);
+void ovl_set_dir_cache(struct inode *inode, struct ovl_dir_cache *cache);
bool ovl_dentry_is_opaque(struct dentry *dentry);
bool ovl_dentry_is_whiteout(struct dentry *dentry);
void ovl_dentry_set_opaque(struct dentry *dentry);
@@ -217,7 +217,7 @@
void ovl_inode_init(struct inode *inode, struct dentry *upperdentry,
struct dentry *lowerdentry);
void ovl_inode_update(struct inode *inode, struct dentry *upperdentry);
-void ovl_dentry_version_inc(struct dentry *dentry);
+void ovl_dentry_version_inc(struct dentry *dentry, bool impurity);
u64 ovl_dentry_version_get(struct dentry *dentry);
bool ovl_is_whiteout(struct dentry *dentry);
struct file *ovl_path_open(struct path *path, int flags);
@@ -229,6 +229,7 @@
int xerr);
int ovl_set_impure(struct dentry *dentry, struct dentry *upperdentry);
void ovl_set_flag(unsigned long flag, struct inode *inode);
+void ovl_clear_flag(unsigned long flag, struct inode *inode);
bool ovl_test_flag(unsigned long flag, struct inode *inode);
bool ovl_inuse_trylock(struct dentry *dentry);
void ovl_inuse_unlock(struct dentry *dentry);
@@ -256,6 +257,7 @@
int ovl_check_empty_dir(struct dentry *dentry, struct list_head *list);
void ovl_cleanup_whiteouts(struct dentry *upper, struct list_head *list);
void ovl_cache_free(struct list_head *list);
+void ovl_dir_cache_free(struct inode *inode);
int ovl_check_d_type_supported(struct path *realpath);
void ovl_workdir_cleanup(struct inode *dir, struct vfsmount *mnt,
struct dentry *dentry, int level);
diff --git a/fs/overlayfs/readdir.c b/fs/overlayfs/readdir.c
index 2aab370..3e27e45 100644
--- a/fs/overlayfs/readdir.c
+++ b/fs/overlayfs/readdir.c
@@ -34,13 +34,14 @@
long refcount;
u64 version;
struct list_head entries;
+ struct rb_root root;
};
struct ovl_readdir_data {
struct dir_context ctx;
struct dentry *dentry;
bool is_lowest;
- struct rb_root root;
+ struct rb_root *root;
struct list_head *list;
struct list_head middle;
struct ovl_cache_entry *first_maybe_whiteout;
@@ -61,7 +62,33 @@
static struct ovl_cache_entry *ovl_cache_entry_from_node(struct rb_node *n)
{
- return container_of(n, struct ovl_cache_entry, node);
+ return rb_entry(n, struct ovl_cache_entry, node);
+}
+
+static bool ovl_cache_entry_find_link(const char *name, int len,
+ struct rb_node ***link,
+ struct rb_node **parent)
+{
+ bool found = false;
+ struct rb_node **newp = *link;
+
+ while (!found && *newp) {
+ int cmp;
+ struct ovl_cache_entry *tmp;
+
+ *parent = *newp;
+ tmp = ovl_cache_entry_from_node(*newp);
+ cmp = strncmp(name, tmp->name, len);
+ if (cmp > 0)
+ newp = &tmp->node.rb_right;
+ else if (cmp < 0 || len < tmp->len)
+ newp = &tmp->node.rb_left;
+ else
+ found = true;
+ }
+ *link = newp;
+
+ return found;
}
static struct ovl_cache_entry *ovl_cache_entry_find(struct rb_root *root,
@@ -144,24 +171,12 @@
const char *name, int len, u64 ino,
unsigned int d_type)
{
- struct rb_node **newp = &rdd->root.rb_node;
+ struct rb_node **newp = &rdd->root->rb_node;
struct rb_node *parent = NULL;
struct ovl_cache_entry *p;
- while (*newp) {
- int cmp;
- struct ovl_cache_entry *tmp;
-
- parent = *newp;
- tmp = ovl_cache_entry_from_node(*newp);
- cmp = strncmp(name, tmp->name, len);
- if (cmp > 0)
- newp = &tmp->node.rb_right;
- else if (cmp < 0 || len < tmp->len)
- newp = &tmp->node.rb_left;
- else
- return 0;
- }
+ if (ovl_cache_entry_find_link(name, len, &newp, &parent))
+ return 0;
p = ovl_cache_entry_new(rdd, name, len, ino, d_type);
if (p == NULL) {
@@ -171,7 +186,7 @@
list_add_tail(&p->l_node, rdd->list);
rb_link_node(&p->node, parent, newp);
- rb_insert_color(&p->node, &rdd->root);
+ rb_insert_color(&p->node, rdd->root);
return 0;
}
@@ -182,7 +197,7 @@
{
struct ovl_cache_entry *p;
- p = ovl_cache_entry_find(&rdd->root, name, namelen);
+ p = ovl_cache_entry_find(rdd->root, name, namelen);
if (p) {
list_move_tail(&p->l_node, &rdd->middle);
} else {
@@ -207,6 +222,16 @@
INIT_LIST_HEAD(list);
}
+void ovl_dir_cache_free(struct inode *inode)
+{
+ struct ovl_dir_cache *cache = ovl_dir_cache(inode);
+
+ if (cache) {
+ ovl_cache_free(&cache->entries);
+ kfree(cache);
+ }
+}
+
static void ovl_cache_put(struct ovl_dir_file *od, struct dentry *dentry)
{
struct ovl_dir_cache *cache = od->cache;
@@ -214,8 +239,8 @@
WARN_ON(cache->refcount <= 0);
cache->refcount--;
if (!cache->refcount) {
- if (ovl_dir_cache(dentry) == cache)
- ovl_set_dir_cache(dentry, NULL);
+ if (ovl_dir_cache(d_inode(dentry)) == cache)
+ ovl_set_dir_cache(d_inode(dentry), NULL);
ovl_cache_free(&cache->entries);
kfree(cache);
@@ -308,7 +333,8 @@
od->is_real = false;
}
-static int ovl_dir_read_merged(struct dentry *dentry, struct list_head *list)
+static int ovl_dir_read_merged(struct dentry *dentry, struct list_head *list,
+ struct rb_root *root)
{
int err;
struct path realpath;
@@ -316,7 +342,7 @@
.ctx.actor = ovl_fill_merge,
.dentry = dentry,
.list = list,
- .root = RB_ROOT,
+ .root = root,
.is_lowest = false,
};
int idx, next;
@@ -362,12 +388,13 @@
int res;
struct ovl_dir_cache *cache;
- cache = ovl_dir_cache(dentry);
+ cache = ovl_dir_cache(d_inode(dentry));
if (cache && ovl_dentry_version_get(dentry) == cache->version) {
+ WARN_ON(!cache->refcount);
cache->refcount++;
return cache;
}
- ovl_set_dir_cache(dentry, NULL);
+ ovl_set_dir_cache(d_inode(dentry), NULL);
cache = kzalloc(sizeof(struct ovl_dir_cache), GFP_KERNEL);
if (!cache)
@@ -375,8 +402,9 @@
cache->refcount = 1;
INIT_LIST_HEAD(&cache->entries);
+ cache->root = RB_ROOT;
- res = ovl_dir_read_merged(dentry, &cache->entries);
+ res = ovl_dir_read_merged(dentry, &cache->entries, &cache->root);
if (res) {
ovl_cache_free(&cache->entries);
kfree(cache);
@@ -384,7 +412,7 @@
}
cache->version = ovl_dentry_version_get(dentry);
- ovl_set_dir_cache(dentry, cache);
+ ovl_set_dir_cache(d_inode(dentry), cache);
return cache;
}
@@ -458,6 +486,169 @@
goto out;
}
+static int ovl_fill_plain(struct dir_context *ctx, const char *name,
+ int namelen, loff_t offset, u64 ino,
+ unsigned int d_type)
+{
+ struct ovl_cache_entry *p;
+ struct ovl_readdir_data *rdd =
+ container_of(ctx, struct ovl_readdir_data, ctx);
+
+ rdd->count++;
+ p = ovl_cache_entry_new(rdd, name, namelen, ino, d_type);
+ if (p == NULL) {
+ rdd->err = -ENOMEM;
+ return -ENOMEM;
+ }
+ list_add_tail(&p->l_node, rdd->list);
+
+ return 0;
+}
+
+static int ovl_dir_read_impure(struct path *path, struct list_head *list,
+ struct rb_root *root)
+{
+ int err;
+ struct path realpath;
+ struct ovl_cache_entry *p, *n;
+ struct ovl_readdir_data rdd = {
+ .ctx.actor = ovl_fill_plain,
+ .list = list,
+ .root = root,
+ };
+
+ INIT_LIST_HEAD(list);
+ *root = RB_ROOT;
+ ovl_path_upper(path->dentry, &realpath);
+
+ err = ovl_dir_read(&realpath, &rdd);
+ if (err)
+ return err;
+
+ list_for_each_entry_safe(p, n, list, l_node) {
+ if (strcmp(p->name, ".") != 0 &&
+ strcmp(p->name, "..") != 0) {
+ err = ovl_cache_update_ino(path, p);
+ if (err)
+ return err;
+ }
+ if (p->ino == p->real_ino) {
+ list_del(&p->l_node);
+ kfree(p);
+ } else {
+ struct rb_node **newp = &root->rb_node;
+ struct rb_node *parent = NULL;
+
+ if (WARN_ON(ovl_cache_entry_find_link(p->name, p->len,
+ &newp, &parent)))
+ return -EIO;
+
+ rb_link_node(&p->node, parent, newp);
+ rb_insert_color(&p->node, root);
+ }
+ }
+ return 0;
+}
+
+static struct ovl_dir_cache *ovl_cache_get_impure(struct path *path)
+{
+ int res;
+ struct dentry *dentry = path->dentry;
+ struct ovl_dir_cache *cache;
+
+ cache = ovl_dir_cache(d_inode(dentry));
+ if (cache && ovl_dentry_version_get(dentry) == cache->version)
+ return cache;
+
+ /* Impure cache is not refcounted, free it here */
+ ovl_dir_cache_free(d_inode(dentry));
+ ovl_set_dir_cache(d_inode(dentry), NULL);
+
+ cache = kzalloc(sizeof(struct ovl_dir_cache), GFP_KERNEL);
+ if (!cache)
+ return ERR_PTR(-ENOMEM);
+
+ res = ovl_dir_read_impure(path, &cache->entries, &cache->root);
+ if (res) {
+ ovl_cache_free(&cache->entries);
+ kfree(cache);
+ return ERR_PTR(res);
+ }
+ if (list_empty(&cache->entries)) {
+ /* Good oportunity to get rid of an unnecessary "impure" flag */
+ ovl_do_removexattr(ovl_dentry_upper(dentry), OVL_XATTR_IMPURE);
+ ovl_clear_flag(OVL_IMPURE, d_inode(dentry));
+ kfree(cache);
+ return NULL;
+ }
+
+ cache->version = ovl_dentry_version_get(dentry);
+ ovl_set_dir_cache(d_inode(dentry), cache);
+
+ return cache;
+}
+
+struct ovl_readdir_translate {
+ struct dir_context *orig_ctx;
+ struct ovl_dir_cache *cache;
+ struct dir_context ctx;
+ u64 parent_ino;
+};
+
+static int ovl_fill_real(struct dir_context *ctx, const char *name,
+ int namelen, loff_t offset, u64 ino,
+ unsigned int d_type)
+{
+ struct ovl_readdir_translate *rdt =
+ container_of(ctx, struct ovl_readdir_translate, ctx);
+ struct dir_context *orig_ctx = rdt->orig_ctx;
+
+ if (rdt->parent_ino && strcmp(name, "..") == 0)
+ ino = rdt->parent_ino;
+ else if (rdt->cache) {
+ struct ovl_cache_entry *p;
+
+ p = ovl_cache_entry_find(&rdt->cache->root, name, namelen);
+ if (p)
+ ino = p->ino;
+ }
+
+ return orig_ctx->actor(orig_ctx, name, namelen, offset, ino, d_type);
+}
+
+static int ovl_iterate_real(struct file *file, struct dir_context *ctx)
+{
+ int err;
+ struct ovl_dir_file *od = file->private_data;
+ struct dentry *dir = file->f_path.dentry;
+ struct ovl_readdir_translate rdt = {
+ .ctx.actor = ovl_fill_real,
+ .orig_ctx = ctx,
+ };
+
+ if (OVL_TYPE_MERGE(ovl_path_type(dir->d_parent))) {
+ struct kstat stat;
+ struct path statpath = file->f_path;
+
+ statpath.dentry = dir->d_parent;
+ err = vfs_getattr(&statpath, &stat, STATX_INO, 0);
+ if (err)
+ return err;
+
+ WARN_ON_ONCE(dir->d_sb->s_dev != stat.dev);
+ rdt.parent_ino = stat.ino;
+ }
+
+ if (ovl_test_flag(OVL_IMPURE, d_inode(dir))) {
+ rdt.cache = ovl_cache_get_impure(&file->f_path);
+ if (IS_ERR(rdt.cache))
+ return PTR_ERR(rdt.cache);
+ }
+
+ return iterate_dir(od->realfile, &rdt.ctx);
+}
+
+
static int ovl_iterate(struct file *file, struct dir_context *ctx)
{
struct ovl_dir_file *od = file->private_data;
@@ -468,8 +659,19 @@
if (!ctx->pos)
ovl_dir_reset(file);
- if (od->is_real)
+ if (od->is_real) {
+ /*
+ * If parent is merge, then need to adjust d_ino for '..', if
+ * dir is impure then need to adjust d_ino for copied up
+ * entries.
+ */
+ if (ovl_same_sb(dentry->d_sb) &&
+ (ovl_test_flag(OVL_IMPURE, d_inode(dentry)) ||
+ OVL_TYPE_MERGE(ovl_path_type(dentry->d_parent)))) {
+ return ovl_iterate_real(file, ctx);
+ }
return iterate_dir(od->realfile, ctx);
+ }
if (!od->cache) {
struct ovl_dir_cache *cache;
@@ -634,8 +836,9 @@
{
int err;
struct ovl_cache_entry *p;
+ struct rb_root root = RB_ROOT;
- err = ovl_dir_read_merged(dentry, list);
+ err = ovl_dir_read_merged(dentry, list, &root);
if (err)
return err;
@@ -724,12 +927,13 @@
int err;
struct inode *dir = path->dentry->d_inode;
LIST_HEAD(list);
+ struct rb_root root = RB_ROOT;
struct ovl_cache_entry *p;
struct ovl_readdir_data rdd = {
.ctx.actor = ovl_fill_merge,
.dentry = NULL,
.list = &list,
- .root = RB_ROOT,
+ .root = &root,
.is_lowest = false,
};
@@ -787,12 +991,13 @@
struct inode *dir = dentry->d_inode;
struct path path = { .mnt = mnt, .dentry = dentry };
LIST_HEAD(list);
+ struct rb_root root = RB_ROOT;
struct ovl_cache_entry *p;
struct ovl_readdir_data rdd = {
.ctx.actor = ovl_fill_merge,
.dentry = NULL,
.list = &list,
- .root = RB_ROOT,
+ .root = &root,
.is_lowest = false,
};
diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
index d86e89f..40d4939 100644
--- a/fs/overlayfs/super.c
+++ b/fs/overlayfs/super.c
@@ -198,6 +198,7 @@
dput(oi->__upperdentry);
kfree(oi->redirect);
+ ovl_dir_cache_free(inode);
mutex_destroy(&oi->lock);
call_rcu(&inode->i_rcu, ovl_i_callback);
diff --git a/fs/overlayfs/util.c b/fs/overlayfs/util.c
index f46ad75..1177945 100644
--- a/fs/overlayfs/util.c
+++ b/fs/overlayfs/util.c
@@ -180,14 +180,14 @@
}
-struct ovl_dir_cache *ovl_dir_cache(struct dentry *dentry)
+struct ovl_dir_cache *ovl_dir_cache(struct inode *inode)
{
- return OVL_I(d_inode(dentry))->cache;
+ return OVL_I(inode)->cache;
}
-void ovl_set_dir_cache(struct dentry *dentry, struct ovl_dir_cache *cache)
+void ovl_set_dir_cache(struct inode *inode, struct ovl_dir_cache *cache)
{
- OVL_I(d_inode(dentry))->cache = cache;
+ OVL_I(inode)->cache = cache;
}
bool ovl_dentry_is_opaque(struct dentry *dentry)
@@ -275,12 +275,19 @@
}
}
-void ovl_dentry_version_inc(struct dentry *dentry)
+void ovl_dentry_version_inc(struct dentry *dentry, bool impurity)
{
struct inode *inode = d_inode(dentry);
WARN_ON(!inode_is_locked(inode));
- OVL_I(inode)->version++;
+ /*
+ * Version is used by readdir code to keep cache consistent. For merge
+ * dirs all changes need to be noted. For non-merge dirs, cache only
+ * contains impure (ones which have been copied up and have origins)
+ * entries, so only need to note changes to impure entries.
+ */
+ if (OVL_TYPE_MERGE(ovl_path_type(dentry)) || impurity)
+ OVL_I(inode)->version++;
}
u64 ovl_dentry_version_get(struct dentry *dentry)
@@ -382,6 +389,11 @@
set_bit(flag, &OVL_I(inode)->flags);
}
+void ovl_clear_flag(unsigned long flag, struct inode *inode)
+{
+ clear_bit(flag, &OVL_I(inode)->flags);
+}
+
bool ovl_test_flag(unsigned long flag, struct inode *inode)
{
return test_bit(flag, &OVL_I(inode)->flags);