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readdir.c
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readdir.c
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// SPDX-License-Identifier: GPL-2.0-only
/*
*
* Copyright (C) 2011 Novell Inc.
*/
#include <linux/fs.h>
#include <linux/slab.h>
#include <linux/namei.h>
#include <linux/file.h>
#include <linux/xattr.h>
#include <linux/rbtree.h>
#include <linux/security.h>
#include <linux/cred.h>
#include <linux/ratelimit.h>
#include "overlayfs.h"
struct ovl_cache_entry {
unsigned int len;
unsigned int type;
u64 real_ino;
u64 ino;
struct list_head l_node;
struct rb_node node;
struct ovl_cache_entry *next_maybe_whiteout;
bool is_upper;
bool is_whiteout;
char name[];
};
struct ovl_dir_cache {
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 list_head *list;
struct list_head middle;
struct ovl_cache_entry *first_maybe_whiteout;
int count;
int err;
bool is_upper;
bool d_type_supported;
};
struct ovl_dir_file {
bool is_real;
bool is_upper;
struct ovl_dir_cache *cache;
struct list_head *cursor;
struct file *realfile;
struct file *upperfile;
};
static struct ovl_cache_entry *ovl_cache_entry_from_node(struct rb_node *n)
{
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,
const char *name, int len)
{
struct rb_node *node = root->rb_node;
int cmp;
while (node) {
struct ovl_cache_entry *p = ovl_cache_entry_from_node(node);
cmp = strncmp(name, p->name, len);
if (cmp > 0)
node = p->node.rb_right;
else if (cmp < 0 || len < p->len)
node = p->node.rb_left;
else
return p;
}
return NULL;
}
static bool ovl_calc_d_ino(struct ovl_readdir_data *rdd,
struct ovl_cache_entry *p)
{
/* Don't care if not doing ovl_iter() */
if (!rdd->dentry)
return false;
/* Always recalc d_ino when remapping lower inode numbers */
if (ovl_xino_bits(rdd->dentry->d_sb))
return true;
/* Always recalc d_ino for parent */
if (strcmp(p->name, "..") == 0)
return true;
/* If this is lower, then native d_ino will do */
if (!rdd->is_upper)
return false;
/*
* Recalc d_ino for '.' and for all entries if dir is impure (contains
* copied up entries)
*/
if ((p->name[0] == '.' && p->len == 1) ||
ovl_test_flag(OVL_IMPURE, d_inode(rdd->dentry)))
return true;
return false;
}
static struct ovl_cache_entry *ovl_cache_entry_new(struct ovl_readdir_data *rdd,
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)
return NULL;
memcpy(p->name, name, len);
p->name[len] = '\0';
p->len = len;
p->type = d_type;
p->real_ino = ino;
p->ino = ino;
/* Defer setting d_ino for upper entry to ovl_iterate() */
if (ovl_calc_d_ino(rdd, p))
p->ino = 0;
p->is_upper = rdd->is_upper;
p->is_whiteout = false;
if (d_type == DT_CHR) {
p->next_maybe_whiteout = rdd->first_maybe_whiteout;
rdd->first_maybe_whiteout = p;
}
return p;
}
static int ovl_cache_entry_add_rb(struct ovl_readdir_data *rdd,
const char *name, int len, u64 ino,
unsigned int d_type)
{
struct rb_node **newp = &rdd->root->rb_node;
struct rb_node *parent = NULL;
struct ovl_cache_entry *p;
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) {
rdd->err = -ENOMEM;
return -ENOMEM;
}
list_add_tail(&p->l_node, rdd->list);
rb_link_node(&p->node, parent, newp);
rb_insert_color(&p->node, rdd->root);
return 0;
}
static int ovl_fill_lowest(struct ovl_readdir_data *rdd,
const char *name, int namelen,
loff_t offset, u64 ino, unsigned int d_type)
{
struct ovl_cache_entry *p;
p = ovl_cache_entry_find(rdd->root, name, namelen);
if (p) {
list_move_tail(&p->l_node, &rdd->middle);
} else {
p = ovl_cache_entry_new(rdd, name, namelen, ino, d_type);
if (p == NULL)
rdd->err = -ENOMEM;
else
list_add_tail(&p->l_node, &rdd->middle);
}
return rdd->err;
}
void ovl_cache_free(struct list_head *list)
{
struct ovl_cache_entry *p;
struct ovl_cache_entry *n;
list_for_each_entry_safe(p, n, list, l_node)
kfree(p);
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;
WARN_ON(cache->refcount <= 0);
cache->refcount--;
if (!cache->refcount) {
if (ovl_dir_cache(d_inode(dentry)) == cache)
ovl_set_dir_cache(d_inode(dentry), NULL);
ovl_cache_free(&cache->entries);
kfree(cache);
}
}
static int ovl_fill_merge(struct dir_context *ctx, const char *name,
int namelen, loff_t offset, u64 ino,
unsigned int d_type)
{
struct ovl_readdir_data *rdd =
container_of(ctx, struct ovl_readdir_data, ctx);
rdd->count++;
if (!rdd->is_lowest)
return ovl_cache_entry_add_rb(rdd, name, namelen, ino, d_type);
else
return ovl_fill_lowest(rdd, name, namelen, offset, ino, d_type);
}
static int ovl_check_whiteouts(struct dentry *dir, struct ovl_readdir_data *rdd)
{
int err;
struct ovl_cache_entry *p;
struct dentry *dentry;
const struct cred *old_cred;
old_cred = ovl_override_creds(rdd->dentry->d_sb);
err = down_write_killable(&dir->d_inode->i_rwsem);
if (!err) {
while (rdd->first_maybe_whiteout) {
p = rdd->first_maybe_whiteout;
rdd->first_maybe_whiteout = p->next_maybe_whiteout;
dentry = lookup_one_len(p->name, dir, p->len);
if (!IS_ERR(dentry)) {
p->is_whiteout = ovl_is_whiteout(dentry);
dput(dentry);
}
}
inode_unlock(dir->d_inode);
}
revert_creds(old_cred);
return err;
}
static inline int ovl_dir_read(struct path *realpath,
struct ovl_readdir_data *rdd)
{
struct file *realfile;
int err;
realfile = ovl_path_open(realpath, O_RDONLY | O_LARGEFILE);
if (IS_ERR(realfile))
return PTR_ERR(realfile);
rdd->first_maybe_whiteout = NULL;
rdd->ctx.pos = 0;
do {
rdd->count = 0;
rdd->err = 0;
err = iterate_dir(realfile, &rdd->ctx);
if (err >= 0)
err = rdd->err;
} while (!err && rdd->count);
if (!err && rdd->first_maybe_whiteout && rdd->dentry)
err = ovl_check_whiteouts(realpath->dentry, rdd);
fput(realfile);
return err;
}
static void ovl_dir_reset(struct file *file)
{
struct ovl_dir_file *od = file->private_data;
struct ovl_dir_cache *cache = od->cache;
struct dentry *dentry = file->f_path.dentry;
bool is_real;
if (cache && ovl_dentry_version_get(dentry) != cache->version) {
ovl_cache_put(od, dentry);
od->cache = NULL;
od->cursor = NULL;
}
is_real = ovl_dir_is_real(dentry);
if (od->is_real != is_real) {
/* is_real can only become false when dir is copied up */
if (WARN_ON(is_real))
return;
od->is_real = false;
}
}
static int ovl_dir_read_merged(struct dentry *dentry, struct list_head *list,
struct rb_root *root)
{
int err;
struct path realpath;
struct ovl_readdir_data rdd = {
.ctx.actor = ovl_fill_merge,
.dentry = dentry,
.list = list,
.root = root,
.is_lowest = false,
};
int idx, next;
for (idx = 0; idx != -1; idx = next) {
next = ovl_path_next(idx, dentry, &realpath);
rdd.is_upper = ovl_dentry_upper(dentry) == realpath.dentry;
if (next != -1) {
err = ovl_dir_read(&realpath, &rdd);
if (err)
break;
} else {
/*
* Insert lowest layer entries before upper ones, this
* allows offsets to be reasonably constant
*/
list_add(&rdd.middle, rdd.list);
rdd.is_lowest = true;
err = ovl_dir_read(&realpath, &rdd);
list_del(&rdd.middle);
}
}
return err;
}
static void ovl_seek_cursor(struct ovl_dir_file *od, loff_t pos)
{
struct list_head *p;
loff_t off = 0;
list_for_each(p, &od->cache->entries) {
if (off >= pos)
break;
off++;
}
/* Cursor is safe since the cache is stable */
od->cursor = p;
}
static struct ovl_dir_cache *ovl_cache_get(struct dentry *dentry)
{
int res;
struct ovl_dir_cache *cache;
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(d_inode(dentry), NULL);
cache = kzalloc(sizeof(struct ovl_dir_cache), GFP_KERNEL);
if (!cache)
return ERR_PTR(-ENOMEM);
cache->refcount = 1;
INIT_LIST_HEAD(&cache->entries);
cache->root = RB_ROOT;
res = ovl_dir_read_merged(dentry, &cache->entries, &cache->root);
if (res) {
ovl_cache_free(&cache->entries);
kfree(cache);
return ERR_PTR(res);
}
cache->version = ovl_dentry_version_get(dentry);
ovl_set_dir_cache(d_inode(dentry), cache);
return cache;
}
/* Map inode number to lower fs unique range */
static u64 ovl_remap_lower_ino(u64 ino, int xinobits, int fsid,
const char *name, int namelen, bool warn)
{
unsigned int xinoshift = 64 - xinobits;
if (unlikely(ino >> xinoshift)) {
if (warn) {
pr_warn_ratelimited("d_ino too big (%.*s, ino=%llu, xinobits=%d)\n",
namelen, name, ino, xinobits);
}
return ino;
}
/*
* The lowest xinobit is reserved for mapping the non-peresistent inode
* numbers range, but this range is only exposed via st_ino, not here.
*/
return ino | ((u64)fsid) << (xinoshift + 1);
}
/*
* Set d_ino for upper entries. Non-upper entries should always report
* the uppermost real inode ino and should not call this function.
*
* When not all layer are on same fs, report real ino also for upper.
*
* When all layers are on the same fs, and upper has a reference to
* copy up origin, call vfs_getattr() on the overlay entry to make
* sure that d_ino will be consistent with st_ino from stat(2).
*/
static int ovl_cache_update_ino(struct path *path, struct ovl_cache_entry *p)
{
struct dentry *dir = path->dentry;
struct dentry *this = NULL;
enum ovl_path_type type;
u64 ino = p->real_ino;
int xinobits = ovl_xino_bits(dir->d_sb);
int err = 0;
if (!ovl_same_dev(dir->d_sb))
goto out;
if (p->name[0] == '.') {
if (p->len == 1) {
this = dget(dir);
goto get;
}
if (p->len == 2 && p->name[1] == '.') {
/* we shall not be moved */
this = dget(dir->d_parent);
goto get;
}
}
this = lookup_one_len(p->name, dir, p->len);
if (IS_ERR_OR_NULL(this) || !this->d_inode) {
/* Mark a stale entry */
p->is_whiteout = true;
if (IS_ERR(this)) {
err = PTR_ERR(this);
this = NULL;
goto fail;
}
goto out;
}
get:
type = ovl_path_type(this);
if (OVL_TYPE_ORIGIN(type)) {
struct kstat stat;
struct path statpath = *path;
statpath.dentry = this;
err = vfs_getattr(&statpath, &stat, STATX_INO, 0);
if (err)
goto fail;
/*
* Directory inode is always on overlay st_dev.
* Non-dir with ovl_same_dev() could be on pseudo st_dev in case
* of xino bits overflow.
*/
WARN_ON_ONCE(S_ISDIR(stat.mode) &&
dir->d_sb->s_dev != stat.dev);
ino = stat.ino;
} else if (xinobits && !OVL_TYPE_UPPER(type)) {
ino = ovl_remap_lower_ino(ino, xinobits,
ovl_layer_lower(this)->fsid,
p->name, p->len,
ovl_xino_warn(dir->d_sb));
}
out:
p->ino = ino;
dput(this);
return err;
fail:
pr_warn_ratelimited("failed to look up (%s) for ino (%i)\n",
p->name, err);
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_fs *ofs = OVL_FS(dentry->d_sb);
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)) {
/*
* A good opportunity to get rid of an unneeded "impure" flag.
* Removing the "impure" xattr is best effort.
*/
if (!ovl_want_write(dentry)) {
ovl_do_removexattr(ofs, ovl_dentry_upper(dentry),
OVL_XATTR_IMPURE);
ovl_drop_write(dentry);
}
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;
int fsid;
int xinobits;
bool xinowarn;
};
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;
} else if (rdt->xinobits) {
ino = ovl_remap_lower_ino(ino, rdt->xinobits, rdt->fsid,
name, namelen, rdt->xinowarn);
}
return orig_ctx->actor(orig_ctx, name, namelen, offset, ino, d_type);
}
static bool ovl_is_impure_dir(struct file *file)
{
struct ovl_dir_file *od = file->private_data;
struct inode *dir = d_inode(file->f_path.dentry);
/*
* Only upper dir can be impure, but if we are in the middle of
* iterating a lower real dir, dir could be copied up and marked
* impure. We only want the impure cache if we started iterating
* a real upper dir to begin with.
*/
return od->is_upper && ovl_test_flag(OVL_IMPURE, dir);
}
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;
const struct ovl_layer *lower_layer = ovl_layer_lower(dir);
struct ovl_readdir_translate rdt = {
.ctx.actor = ovl_fill_real,
.orig_ctx = ctx,
.xinobits = ovl_xino_bits(dir->d_sb),
.xinowarn = ovl_xino_warn(dir->d_sb),
};
if (rdt.xinobits && lower_layer)
rdt.fsid = lower_layer->fsid;
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_is_impure_dir(file)) {
rdt.cache = ovl_cache_get_impure(&file->f_path);
if (IS_ERR(rdt.cache))
return PTR_ERR(rdt.cache);
}
err = iterate_dir(od->realfile, &rdt.ctx);
ctx->pos = rdt.ctx.pos;
return err;
}
static int ovl_iterate(struct file *file, struct dir_context *ctx)
{
struct ovl_dir_file *od = file->private_data;
struct dentry *dentry = file->f_path.dentry;
struct ovl_cache_entry *p;
const struct cred *old_cred;
int err;
old_cred = ovl_override_creds(dentry->d_sb);
if (!ctx->pos)
ovl_dir_reset(file);
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_xino_bits(dentry->d_sb) ||
(ovl_same_fs(dentry->d_sb) &&
(ovl_is_impure_dir(file) ||
OVL_TYPE_MERGE(ovl_path_type(dentry->d_parent))))) {
err = ovl_iterate_real(file, ctx);
} else {
err = iterate_dir(od->realfile, ctx);
}
goto out;
}
if (!od->cache) {
struct ovl_dir_cache *cache;
cache = ovl_cache_get(dentry);
err = PTR_ERR(cache);
if (IS_ERR(cache))
goto out;
od->cache = cache;
ovl_seek_cursor(od, ctx->pos);
}
while (od->cursor != &od->cache->entries) {
p = list_entry(od->cursor, struct ovl_cache_entry, l_node);
if (!p->is_whiteout) {
if (!p->ino) {
err = ovl_cache_update_ino(&file->f_path, p);
if (err)
goto out;
}
}
/* ovl_cache_update_ino() sets is_whiteout on stale entry */
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++;
}
err = 0;
out:
revert_creds(old_cred);
return err;
}
static loff_t ovl_dir_llseek(struct file *file, loff_t offset, int origin)
{
loff_t res;
struct ovl_dir_file *od = file->private_data;
inode_lock(file_inode(file));
if (!file->f_pos)
ovl_dir_reset(file);
if (od->is_real) {
res = vfs_llseek(od->realfile, offset, origin);
file->f_pos = od->realfile->f_pos;
} else {
res = -EINVAL;
switch (origin) {
case SEEK_CUR:
offset += file->f_pos;
break;
case SEEK_SET:
break;
default:
goto out_unlock;
}
if (offset < 0)
goto out_unlock;
if (offset != file->f_pos) {
file->f_pos = offset;
if (od->cache)
ovl_seek_cursor(od, offset);
}
res = offset;
}
out_unlock:
inode_unlock(file_inode(file));
return res;
}
static struct file *ovl_dir_open_realfile(const struct file *file,
struct path *realpath)
{
struct file *res;
const struct cred *old_cred;
old_cred = ovl_override_creds(file_inode(file)->i_sb);
res = ovl_path_open(realpath, O_RDONLY | (file->f_flags & O_LARGEFILE));
revert_creds(old_cred);
return res;
}
/*
* Like ovl_real_fdget(), returns upperfile if dir was copied up since open.
* Unlike ovl_real_fdget(), this caches upperfile in file->private_data.
*
* TODO: use same abstract type for file->private_data of dir and file so
* upperfile could also be cached for files as well.
*/
struct file *ovl_dir_real_file(const struct file *file, bool want_upper)
{
struct ovl_dir_file *od = file->private_data;
struct dentry *dentry = file->f_path.dentry;
struct file *old, *realfile = od->realfile;
if (!OVL_TYPE_UPPER(ovl_path_type(dentry)))
return want_upper ? NULL : realfile;
/*
* Need to check if we started out being a lower dir, but got copied up
*/
if (!od->is_upper) {
realfile = READ_ONCE(od->upperfile);
if (!realfile) {
struct path upperpath;
ovl_path_upper(dentry, &upperpath);
realfile = ovl_dir_open_realfile(file, &upperpath);
if (IS_ERR(realfile))
return realfile;
old = cmpxchg_release(&od->upperfile, NULL, realfile);
if (old) {
fput(realfile);
realfile = old;
}
}
}
return realfile;
}
static int ovl_dir_fsync(struct file *file, loff_t start, loff_t end,
int datasync)
{
struct file *realfile;
int err;
err = ovl_sync_status(OVL_FS(file->f_path.dentry->d_sb));
if (err <= 0)
return err;
realfile = ovl_dir_real_file(file, true);
err = PTR_ERR_OR_ZERO(realfile);
/* Nothing to sync for lower */
if (!realfile || err)
return err;
return vfs_fsync_range(realfile, start, end, datasync);
}
static int ovl_dir_release(struct inode *inode, struct file *file)
{
struct ovl_dir_file *od = file->private_data;
if (od->cache) {
inode_lock(inode);
ovl_cache_put(od, file->f_path.dentry);
inode_unlock(inode);
}
fput(od->realfile);
if (od->upperfile)
fput(od->upperfile);
kfree(od);
return 0;
}
static int ovl_dir_open(struct inode *inode, struct file *file)
{
struct path realpath;
struct file *realfile;
struct ovl_dir_file *od;
enum ovl_path_type type;
od = kzalloc(sizeof(struct ovl_dir_file), GFP_KERNEL);
if (!od)
return -ENOMEM;
type = ovl_path_real(file->f_path.dentry, &realpath);
realfile = ovl_dir_open_realfile(file, &realpath);
if (IS_ERR(realfile)) {
kfree(od);
return PTR_ERR(realfile);
}
od->realfile = realfile;
od->is_real = ovl_dir_is_real(file->f_path.dentry);
od->is_upper = OVL_TYPE_UPPER(type);
file->private_data = od;
return 0;
}
const struct file_operations ovl_dir_operations = {
.read = generic_read_dir,
.open = ovl_dir_open,
.iterate = ovl_iterate,
.llseek = ovl_dir_llseek,
.fsync = ovl_dir_fsync,
.release = ovl_dir_release,
};
int ovl_check_empty_dir(struct dentry *dentry, struct list_head *list)
{
int err;
struct ovl_cache_entry *p, *n;
struct rb_root root = RB_ROOT;
const struct cred *old_cred;
old_cred = ovl_override_creds(dentry->d_sb);
err = ovl_dir_read_merged(dentry, list, &root);
revert_creds(old_cred);
if (err)
return err;
err = 0;
list_for_each_entry_safe(p, n, list, l_node) {
/*
* Select whiteouts in upperdir, they should
* be cleared when deleting this directory.
*/
if (p->is_whiteout) {
if (p->is_upper)
continue;
goto del_entry;
}
if (p->name[0] == '.') {
if (p->len == 1)
goto del_entry;
if (p->len == 2 && p->name[1] == '.')
goto del_entry;
}
err = -ENOTEMPTY;
break;
del_entry:
list_del(&p->l_node);
kfree(p);
}