| // 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; |
| } |
| |
| /* |
| * 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, 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) { |
| 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; |
| } |
| 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); |
| } |
| |
| 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("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; |
| } |
| |
| #define OVL_INCOMPATDIR_NAME "incompat" |
| |
| static int 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, |
| }; |
| bool incompat = false; |
| |
| /* |
| * The "work/incompat" directory is treated specially - if it is not |
| * empty, instead of printing a generic error and mounting read-only, |
| * we will error about incompat features and fail the mount. |
| * |
| * When called from ovl_indexdir_cleanup(), path->dentry->d_name.name |
| * starts with '#'. |
| */ |
| if (level == 2 && |
| !strcmp(path->dentry->d_name.name, OVL_INCOMPATDIR_NAME)) |
| incompat = true; |
| |
| 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; |
| } else if (incompat) { |
| pr_err("overlay with incompat feature '%s' cannot be mounted\n", |
| p->name); |
| err = -EINVAL; |
| break; |
| } |
| dentry = lookup_one_len(p->name, path->dentry, p->len); |
| if (IS_ERR(dentry)) |
| continue; |
| if (dentry->d_inode) |
| err = ovl_workdir_cleanup(dir, path->mnt, dentry, level); |
| dput(dentry); |
| if (err) |
| break; |
| } |
| inode_unlock(dir); |
| out: |
| ovl_cache_free(&list); |
| return err; |
| } |
| |
| int ovl_workdir_cleanup(struct inode *dir, struct vfsmount *mnt, |
| struct dentry *dentry, int level) |
| { |
| int err; |
| |
| if (!d_is_dir(dentry) || level > 1) { |
| return ovl_cleanup(dir, dentry); |
| } |
| |
| err = ovl_do_rmdir(dir, dentry); |
| if (err) { |
| struct path path = { .mnt = mnt, .dentry = dentry }; |
| |
| inode_unlock(dir); |
| err = ovl_workdir_cleanup_recurse(&path, level + 1); |
| inode_lock_nested(dir, I_MUTEX_PARENT); |
| if (!err) |
| err = ovl_cleanup(dir, dentry); |
| } |
| |
| return err; |
| } |
| |
| 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 = ovl_upper_mnt(ofs), .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; |
| } |
| /* Cleanup leftover from index create/cleanup attempt */ |
| if (index->d_name.name[0] == '#') { |
| err = ovl_workdir_cleanup(dir, path.mnt, index, 1); |
| if (err) |
| break; |
| goto next; |
| } |
| 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(ofs, 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("failed index dir cleanup (%i)\n", err); |
| return err; |
| } |