diff options
Diffstat (limited to '')
-rw-r--r-- | fs/overlayfs/readdir.c | 112 |
1 files changed, 111 insertions, 1 deletions
diff --git a/fs/overlayfs/readdir.c b/fs/overlayfs/readdir.c index a6cd7b204412..2aab37054027 100644 --- a/fs/overlayfs/readdir.c +++ b/fs/overlayfs/readdir.c @@ -15,11 +15,13 @@ #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; @@ -44,6 +46,7 @@ struct ovl_readdir_data { struct ovl_cache_entry *first_maybe_whiteout; int count; int err; + bool is_upper; bool d_type_supported; }; @@ -82,6 +85,32 @@ static struct ovl_cache_entry *ovl_cache_entry_find(struct rb_root *root, 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 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) @@ -97,7 +126,11 @@ static struct ovl_cache_entry *ovl_cache_entry_new(struct ovl_readdir_data *rdd, 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_whiteout = false; if (d_type == DT_CHR) { @@ -290,6 +323,7 @@ static int ovl_dir_read_merged(struct dentry *dentry, struct list_head *list) 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); @@ -355,11 +389,81 @@ static struct ovl_dir_cache *ovl_cache_get(struct dentry *dentry) return cache; } +/* + * 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 err = 0; + + if (!ovl_same_sb(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; + + WARN_ON_ONCE(dir->d_sb->s_dev != stat.dev); + ino = stat.ino; + } + +out: + p->ino = ino; + dput(this); + return err; + +fail: + pr_warn_ratelimited("overlay: failed to look up (%s) for ino (%i)\n", + p->name, err); + goto out; +} + 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); @@ -380,9 +484,15 @@ static int ovl_iterate(struct file *file, struct dir_context *ctx) while (od->cursor != &od->cache->entries) { p = list_entry(od->cursor, struct ovl_cache_entry, l_node); - if (!p->is_whiteout) + 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++; } |