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- /*
- *
- * Copyright (C) 2011 Novell Inc.
- *
- * This program is free software; you can redistribute it and/or modify it
- * under the terms of the GNU General Public License version 2 as published by
- * the Free Software Foundation.
- */
- #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_DIRECTORY);
- 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;
- }
- /*
- * Can we iterate real dir directly?
- *
- * Non-merge dir may contain whiteouts from a time it was a merge upper, before
- * lower dir was removed under it and possibly before it was rotated from upper
- * to lower layer.
- */
- static bool ovl_dir_is_real(struct dentry *dir)
- {
- return !ovl_test_flag(OVL_WHITEOUTS, d_inode(dir));
- }
- 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)
- {
- if (ino >> (64 - xinobits)) {
- pr_warn_ratelimited("overlayfs: d_ino too big (%.*s, ino=%llu, xinobits=%d)\n",
- namelen, name, ino, xinobits);
- return ino;
- }
- return ino | ((u64)fsid) << (64 - xinobits);
- }
- /*
- * 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_sb(dir->d_sb) && !xinobits)
- 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) {
- 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);
- }
- out:
- p->ino = ino;
- dput(this);
- return err;
- fail:
- pr_warn_ratelimited("overlayfs: 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_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(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;
- };
- 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);
- }
- 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;
- 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),
- };
- 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;
- int err;
- 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_sb(dentry->d_sb) &&
- (ovl_is_impure_dir(file) ||
- 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;
- cache = ovl_cache_get(dentry);
- if (IS_ERR(cache))
- return PTR_ERR(cache);
- 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)
- return err;
- }
- if (!dir_emit(ctx, p->name, p->len, p->ino, p->type))
- break;
- }
- od->cursor = p->l_node.next;
- ctx->pos++;
- }
- return 0;
- }
- 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 int ovl_dir_fsync(struct file *file, loff_t start, loff_t end,
- int datasync)
- {
- struct ovl_dir_file *od = file->private_data;
- struct dentry *dentry = file->f_path.dentry;
- struct file *realfile = od->realfile;
- /* Nothing to sync for lower */
- if (!OVL_TYPE_UPPER(ovl_path_type(dentry)))
- return 0;
- /*
- * Need to check if we started out being a lower dir, but got copied up
- */
- if (!od->is_upper) {
- struct inode *inode = file_inode(file);
- realfile = READ_ONCE(od->upperfile);
- if (!realfile) {
- struct path upperpath;
- ovl_path_upper(dentry, &upperpath);
- realfile = ovl_path_open(&upperpath, O_RDONLY);
- inode_lock(inode);
- if (!od->upperfile) {
- if (IS_ERR(realfile)) {
- inode_unlock(inode);
- return PTR_ERR(realfile);
- }
- smp_store_release(&od->upperfile, realfile);
- } else {
- /* somebody has beaten us to it */
- if (!IS_ERR(realfile))
- fput(realfile);
- realfile = od->upperfile;
- }
- inode_unlock(inode);
- }
- }
- 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_path_open(&realpath, file->f_flags);
- 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);
- }
- return err;
- }
- void ovl_cleanup_whiteouts(struct dentry *upper, struct list_head *list)
- {
- struct ovl_cache_entry *p;
- inode_lock_nested(upper->d_inode, I_MUTEX_CHILD);
- list_for_each_entry(p, list, l_node) {
- struct dentry *dentry;
- if (WARN_ON(!p->is_whiteout || !p->is_upper))
- continue;
- dentry = lookup_one_len(p->name, upper, p->len);
- if (IS_ERR(dentry)) {
- pr_err("overlayfs: lookup '%s/%.*s' failed (%i)\n",
- upper->d_name.name, p->len, p->name,
- (int) PTR_ERR(dentry));
- continue;
- }
- if (dentry->d_inode)
- ovl_cleanup(upper->d_inode, dentry);
- dput(dentry);
- }
- inode_unlock(upper->d_inode);
- }
- static int ovl_check_d_type(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);
- /* Even if d_type is not supported, DT_DIR is returned for . and .. */
- if (!strncmp(name, ".", namelen) || !strncmp(name, "..", namelen))
- return 0;
- if (d_type != DT_UNKNOWN)
- rdd->d_type_supported = true;
- return 0;
- }
- /*
- * Returns 1 if d_type is supported, 0 not supported/unknown. Negative values
- * if error is encountered.
- */
- int ovl_check_d_type_supported(struct path *realpath)
- {
- int err;
- struct ovl_readdir_data rdd = {
- .ctx.actor = ovl_check_d_type,
- .d_type_supported = false,
- };
- err = ovl_dir_read(realpath, &rdd);
- if (err)
- return err;
- return rdd.d_type_supported;
- }
- static void ovl_workdir_cleanup_recurse(struct path *path, int level)
- {
- 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 = &root,
- .is_lowest = false,
- };
- err = ovl_dir_read(path, &rdd);
- if (err)
- goto out;
- inode_lock_nested(dir, I_MUTEX_PARENT);
- list_for_each_entry(p, &list, l_node) {
- struct dentry *dentry;
- if (p->name[0] == '.') {
- if (p->len == 1)
- continue;
- if (p->len == 2 && p->name[1] == '.')
- continue;
- }
- dentry = lookup_one_len(p->name, path->dentry, p->len);
- if (IS_ERR(dentry))
- continue;
- if (dentry->d_inode)
- ovl_workdir_cleanup(dir, path->mnt, dentry, level);
- dput(dentry);
- }
- inode_unlock(dir);
- out:
- ovl_cache_free(&list);
- }
- void ovl_workdir_cleanup(struct inode *dir, struct vfsmount *mnt,
- struct dentry *dentry, int level)
- {
- int err;
- if (!d_is_dir(dentry) || level > 1) {
- ovl_cleanup(dir, dentry);
- return;
- }
- err = ovl_do_rmdir(dir, dentry);
- if (err) {
- struct path path = { .mnt = mnt, .dentry = dentry };
- inode_unlock(dir);
- ovl_workdir_cleanup_recurse(&path, level + 1);
- inode_lock_nested(dir, I_MUTEX_PARENT);
- ovl_cleanup(dir, dentry);
- }
- }
- int ovl_indexdir_cleanup(struct ovl_fs *ofs)
- {
- int err;
- struct dentry *indexdir = ofs->indexdir;
- struct dentry *index = NULL;
- struct inode *dir = indexdir->d_inode;
- struct path path = { .mnt = ofs->upper_mnt, .dentry = indexdir };
- 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 = &root,
- .is_lowest = false,
- };
- err = ovl_dir_read(&path, &rdd);
- if (err)
- goto out;
- inode_lock_nested(dir, I_MUTEX_PARENT);
- list_for_each_entry(p, &list, l_node) {
- if (p->name[0] == '.') {
- if (p->len == 1)
- continue;
- if (p->len == 2 && p->name[1] == '.')
- continue;
- }
- index = lookup_one_len(p->name, indexdir, p->len);
- if (IS_ERR(index)) {
- err = PTR_ERR(index);
- index = NULL;
- break;
- }
- err = ovl_verify_index(ofs, index);
- if (!err) {
- goto next;
- } else if (err == -ESTALE) {
- /* Cleanup stale index entries */
- err = ovl_cleanup(dir, index);
- } else if (err != -ENOENT) {
- /*
- * Abort mount to avoid corrupting the index if
- * an incompatible index entry was found or on out
- * of memory.
- */
- break;
- } else if (ofs->config.nfs_export) {
- /*
- * Whiteout orphan index to block future open by
- * handle after overlay nlink dropped to zero.
- */
- err = ovl_cleanup_and_whiteout(indexdir, dir, index);
- } else {
- /* Cleanup orphan index entries */
- err = ovl_cleanup(dir, index);
- }
- if (err)
- break;
- next:
- dput(index);
- index = NULL;
- }
- dput(index);
- inode_unlock(dir);
- out:
- ovl_cache_free(&list);
- if (err)
- pr_err("overlayfs: failed index dir cleanup (%i)\n", err);
- return err;
- }
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