struct list_head l_node;
struct rb_node node;
bool is_whiteout;
- bool is_cursor;
char name[];
};
struct rb_root root;
struct list_head *list;
struct list_head middle;
+ struct dentry *dir;
int count;
int err;
};
bool is_real;
bool is_upper;
struct ovl_dir_cache *cache;
- struct ovl_cache_entry cursor;
+ struct list_head *cursor;
struct file *realfile;
struct file *upperfile;
};
return NULL;
}
-static struct ovl_cache_entry *ovl_cache_entry_new(const char *name, int len,
+static struct ovl_cache_entry *ovl_cache_entry_new(struct dentry *dir,
+ const char *name, int len,
u64 ino, unsigned int d_type)
{
struct ovl_cache_entry *p;
size_t size = offsetof(struct ovl_cache_entry, name[len + 1]);
p = kmalloc(size, GFP_KERNEL);
- if (p) {
- memcpy(p->name, name, len);
- p->name[len] = '\0';
- p->len = len;
- p->type = d_type;
- p->ino = ino;
- p->is_whiteout = false;
- p->is_cursor = false;
- }
+ if (!p)
+ return NULL;
+
+ memcpy(p->name, name, len);
+ p->name[len] = '\0';
+ p->len = len;
+ p->type = d_type;
+ p->ino = ino;
+ p->is_whiteout = false;
+
+ if (d_type == DT_CHR) {
+ struct dentry *dentry;
+ const struct cred *old_cred;
+ struct cred *override_cred;
+
+ override_cred = prepare_creds();
+ if (!override_cred) {
+ kfree(p);
+ return NULL;
+ }
+
+ /*
+ * CAP_DAC_OVERRIDE for lookup
+ */
+ cap_raise(override_cred->cap_effective, CAP_DAC_OVERRIDE);
+ old_cred = override_creds(override_cred);
+ dentry = lookup_one_len(name, dir, len);
+ if (!IS_ERR(dentry)) {
+ p->is_whiteout = ovl_is_whiteout(dentry);
+ dput(dentry);
+ }
+ revert_creds(old_cred);
+ put_cred(override_cred);
+ }
return p;
}
return 0;
}
- p = ovl_cache_entry_new(name, len, ino, d_type);
+ p = ovl_cache_entry_new(rdd->dir, name, len, ino, d_type);
if (p == NULL)
return -ENOMEM;
if (p) {
list_move_tail(&p->l_node, &rdd->middle);
} else {
- p = ovl_cache_entry_new(name, namelen, ino, d_type);
+ p = ovl_cache_entry_new(rdd->dir, name, namelen, ino, d_type);
if (p == NULL)
rdd->err = -ENOMEM;
else
{
struct ovl_dir_cache *cache = od->cache;
- list_del_init(&od->cursor.l_node);
WARN_ON(cache->refcount <= 0);
cache->refcount--;
if (!cache->refcount) {
if (IS_ERR(realfile))
return PTR_ERR(realfile);
+ rdd->dir = realpath->dentry;
rdd->ctx.pos = 0;
do {
rdd->count = 0;
if (cache && ovl_dentry_version_get(dentry) != cache->version) {
ovl_cache_put(od, dentry);
od->cache = NULL;
+ od->cursor = NULL;
}
- WARN_ON(!od->is_real && type != OVL_PATH_MERGE);
- if (od->is_real && type == OVL_PATH_MERGE)
+ WARN_ON(!od->is_real && !OVL_TYPE_MERGE(type));
+ if (od->is_real && OVL_TYPE_MERGE(type))
od->is_real = false;
}
-static int ovl_dir_mark_whiteouts(struct dentry *dir,
- struct ovl_readdir_data *rdd)
-{
- struct ovl_cache_entry *p;
- struct dentry *dentry;
- const struct cred *old_cred;
- struct cred *override_cred;
-
- override_cred = prepare_creds();
- if (!override_cred) {
- ovl_cache_free(rdd->list);
- return -ENOMEM;
- }
-
- /*
- * CAP_DAC_OVERRIDE for lookup
- */
- cap_raise(override_cred->cap_effective, CAP_DAC_OVERRIDE);
- old_cred = override_creds(override_cred);
-
- mutex_lock(&dir->d_inode->i_mutex);
- list_for_each_entry(p, rdd->list, l_node) {
- if (p->is_cursor)
- continue;
-
- if (p->type != DT_CHR)
- continue;
-
- dentry = lookup_one_len(p->name, dir, p->len);
- if (IS_ERR(dentry))
- continue;
-
- p->is_whiteout = ovl_is_whiteout(dentry);
- dput(dentry);
- }
- mutex_unlock(&dir->d_inode->i_mutex);
-
- revert_creds(old_cred);
- put_cred(override_cred);
-
- return 0;
-}
-
static int ovl_dir_read_merged(struct dentry *dentry, struct list_head *list)
{
int err;
- struct path lowerpath;
- struct path upperpath;
+ struct path realpath;
struct ovl_readdir_data rdd = {
.ctx.actor = ovl_fill_merge,
.list = list,
.root = RB_ROOT,
.is_merge = false,
};
+ int idx, next;
- ovl_path_lower(dentry, &lowerpath);
- ovl_path_upper(dentry, &upperpath);
+ for (idx = 0; idx != -1; idx = next) {
+ next = ovl_path_next(idx, dentry, &realpath);
- if (upperpath.dentry) {
- err = ovl_dir_read(&upperpath, &rdd);
- if (err)
- goto out;
-
- if (lowerpath.dentry) {
- err = ovl_dir_mark_whiteouts(upperpath.dentry, &rdd);
+ if (next != -1) {
+ err = ovl_dir_read(&realpath, &rdd);
if (err)
- goto out;
+ break;
+ } else {
+ /*
+ * Insert lowest layer entries before upper ones, this
+ * allows offsets to be reasonably constant
+ */
+ list_add(&rdd.middle, rdd.list);
+ rdd.is_merge = true;
+ err = ovl_dir_read(&realpath, &rdd);
+ list_del(&rdd.middle);
}
}
- if (lowerpath.dentry) {
- /*
- * Insert lowerpath entries before upperpath ones, this allows
- * offsets to be reasonably constant
- */
- list_add(&rdd.middle, rdd.list);
- rdd.is_merge = true;
- err = ovl_dir_read(&lowerpath, &rdd);
- list_del(&rdd.middle);
- }
-out:
return err;
}
static void ovl_seek_cursor(struct ovl_dir_file *od, loff_t pos)
{
- struct ovl_cache_entry *p;
+ struct list_head *p;
loff_t off = 0;
- list_for_each_entry(p, &od->cache->entries, l_node) {
- if (p->is_cursor)
- continue;
+ list_for_each(p, &od->cache->entries) {
if (off >= pos)
break;
off++;
}
- list_move_tail(&od->cursor.l_node, &p->l_node);
+ /* Cursor is safe since the cache is stable */
+ od->cursor = p;
}
static struct ovl_dir_cache *ovl_cache_get(struct dentry *dentry)
{
struct ovl_dir_file *od = file->private_data;
struct dentry *dentry = file->f_path.dentry;
+ struct ovl_cache_entry *p;
if (!ctx->pos)
ovl_dir_reset(file);
ovl_seek_cursor(od, ctx->pos);
}
- while (od->cursor.l_node.next != &od->cache->entries) {
- struct ovl_cache_entry *p;
-
- p = list_entry(od->cursor.l_node.next, struct ovl_cache_entry, l_node);
- /* Skip cursors */
- if (!p->is_cursor) {
- if (!p->is_whiteout) {
- if (!dir_emit(ctx, p->name, p->len, p->ino, p->type))
- break;
- }
- ctx->pos++;
- }
- list_move(&od->cursor.l_node, &p->l_node);
+ while (od->cursor != &od->cache->entries) {
+ p = list_entry(od->cursor, struct ovl_cache_entry, l_node);
+ if (!p->is_whiteout)
+ if (!dir_emit(ctx, p->name, p->len, p->ino, p->type))
+ break;
+ od->cursor = p->l_node.next;
+ ctx->pos++;
}
return 0;
}
/*
* Need to check if we started out being a lower dir, but got copied up
*/
- if (!od->is_upper && ovl_path_type(dentry) != OVL_PATH_LOWER) {
+ if (!od->is_upper && OVL_TYPE_UPPER(ovl_path_type(dentry))) {
struct inode *inode = file_inode(file);
realfile = lockless_dereference(od->upperfile);
kfree(od);
return PTR_ERR(realfile);
}
- INIT_LIST_HEAD(&od->cursor.l_node);
od->realfile = realfile;
- od->is_real = (type != OVL_PATH_MERGE);
- od->is_upper = (type != OVL_PATH_LOWER);
- od->cursor.is_cursor = true;
+ od->is_real = !OVL_TYPE_MERGE(type);
+ od->is_upper = OVL_TYPE_UPPER(type);
file->private_data = od;
return 0;
projects / cascardo / linux.git / blobdiff