From e5fd91f1ef340da553f7a79da9540c3db711c937 Mon Sep 17 00:00:00 2001 From: André Fabian Silva Delgado Date: Tue, 8 Sep 2015 01:01:14 -0300 Subject: Linux-libre 4.2-gnu --- fs/overlayfs/inode.c | 60 ++++++++++++------------- fs/overlayfs/overlayfs.h | 1 + fs/overlayfs/super.c | 114 +++++++++++++++++++++++++++++++++++++---------- 3 files changed, 120 insertions(+), 55 deletions(-) (limited to 'fs/overlayfs') diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c index 04f124884..d9da5a4e9 100644 --- a/fs/overlayfs/inode.c +++ b/fs/overlayfs/inode.c @@ -140,11 +140,12 @@ struct ovl_link_data { void *cookie; }; -static void *ovl_follow_link(struct dentry *dentry, struct nameidata *nd) +static const char *ovl_follow_link(struct dentry *dentry, void **cookie) { - void *ret; struct dentry *realdentry; struct inode *realinode; + struct ovl_link_data *data = NULL; + const char *ret; realdentry = ovl_dentry_real(dentry); realinode = realdentry->d_inode; @@ -152,28 +153,28 @@ static void *ovl_follow_link(struct dentry *dentry, struct nameidata *nd) if (WARN_ON(!realinode->i_op->follow_link)) return ERR_PTR(-EPERM); - ret = realinode->i_op->follow_link(realdentry, nd); - if (IS_ERR(ret)) - return ret; - if (realinode->i_op->put_link) { - struct ovl_link_data *data; - data = kmalloc(sizeof(struct ovl_link_data), GFP_KERNEL); - if (!data) { - realinode->i_op->put_link(realdentry, nd, ret); + if (!data) return ERR_PTR(-ENOMEM); - } data->realdentry = realdentry; - data->cookie = ret; + } - return data; - } else { - return NULL; + ret = realinode->i_op->follow_link(realdentry, cookie); + if (IS_ERR_OR_NULL(ret)) { + kfree(data); + return ret; } + + if (data) + data->cookie = *cookie; + + *cookie = data; + + return ret; } -static void ovl_put_link(struct dentry *dentry, struct nameidata *nd, void *c) +static void ovl_put_link(struct inode *unused, void *c) { struct inode *realinode; struct ovl_link_data *data = c; @@ -182,7 +183,7 @@ static void ovl_put_link(struct dentry *dentry, struct nameidata *nd, void *c) return; realinode = data->realdentry->d_inode; - realinode->i_op->put_link(data->realdentry, nd, data->cookie); + realinode->i_op->put_link(realinode, data->cookie); kfree(data); } @@ -336,37 +337,33 @@ static bool ovl_open_need_copy_up(int flags, enum ovl_path_type type, return true; } -static int ovl_dentry_open(struct dentry *dentry, struct file *file, - const struct cred *cred) +struct inode *ovl_d_select_inode(struct dentry *dentry, unsigned file_flags) { int err; struct path realpath; enum ovl_path_type type; - bool want_write = false; + + if (d_is_dir(dentry)) + return d_backing_inode(dentry); type = ovl_path_real(dentry, &realpath); - if (ovl_open_need_copy_up(file->f_flags, type, realpath.dentry)) { - want_write = true; + if (ovl_open_need_copy_up(file_flags, type, realpath.dentry)) { err = ovl_want_write(dentry); if (err) - goto out; + return ERR_PTR(err); - if (file->f_flags & O_TRUNC) + if (file_flags & O_TRUNC) err = ovl_copy_up_last(dentry, NULL, true); else err = ovl_copy_up(dentry); + ovl_drop_write(dentry); if (err) - goto out_drop_write; + return ERR_PTR(err); ovl_path_upper(dentry, &realpath); } - err = vfs_open(&realpath, file, cred); -out_drop_write: - if (want_write) - ovl_drop_write(dentry); -out: - return err; + return d_backing_inode(realpath.dentry); } static const struct inode_operations ovl_file_inode_operations = { @@ -377,7 +374,6 @@ static const struct inode_operations ovl_file_inode_operations = { .getxattr = ovl_getxattr, .listxattr = ovl_listxattr, .removexattr = ovl_removexattr, - .dentry_open = ovl_dentry_open, }; static const struct inode_operations ovl_symlink_inode_operations = { diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h index 17ac5afc9..ea5a40b06 100644 --- a/fs/overlayfs/overlayfs.h +++ b/fs/overlayfs/overlayfs.h @@ -173,6 +173,7 @@ ssize_t ovl_getxattr(struct dentry *dentry, const char *name, void *value, size_t size); ssize_t ovl_listxattr(struct dentry *dentry, char *list, size_t size); int ovl_removexattr(struct dentry *dentry, const char *name); +struct inode *ovl_d_select_inode(struct dentry *dentry, unsigned file_flags); struct inode *ovl_new_inode(struct super_block *sb, umode_t mode, struct ovl_entry *oe); diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c index bf8537c7f..7466ff339 100644 --- a/fs/overlayfs/super.c +++ b/fs/overlayfs/super.c @@ -273,8 +273,56 @@ static void ovl_dentry_release(struct dentry *dentry) } } +static int ovl_dentry_revalidate(struct dentry *dentry, unsigned int flags) +{ + struct ovl_entry *oe = dentry->d_fsdata; + unsigned int i; + int ret = 1; + + for (i = 0; i < oe->numlower; i++) { + struct dentry *d = oe->lowerstack[i].dentry; + + if (d->d_flags & DCACHE_OP_REVALIDATE) { + ret = d->d_op->d_revalidate(d, flags); + if (ret < 0) + return ret; + if (!ret) { + if (!(flags & LOOKUP_RCU)) + d_invalidate(d); + return -ESTALE; + } + } + } + return 1; +} + +static int ovl_dentry_weak_revalidate(struct dentry *dentry, unsigned int flags) +{ + struct ovl_entry *oe = dentry->d_fsdata; + unsigned int i; + int ret = 1; + + for (i = 0; i < oe->numlower; i++) { + struct dentry *d = oe->lowerstack[i].dentry; + + if (d->d_flags & DCACHE_OP_WEAK_REVALIDATE) { + ret = d->d_op->d_weak_revalidate(d, flags); + if (ret <= 0) + break; + } + } + return ret; +} + static const struct dentry_operations ovl_dentry_operations = { .d_release = ovl_dentry_release, + .d_select_inode = ovl_d_select_inode, +}; + +static const struct dentry_operations ovl_reval_dentry_operations = { + .d_release = ovl_dentry_release, + .d_revalidate = ovl_dentry_revalidate, + .d_weak_revalidate = ovl_dentry_weak_revalidate, }; static struct ovl_entry *ovl_alloc_entry(unsigned int numlower) @@ -288,6 +336,20 @@ static struct ovl_entry *ovl_alloc_entry(unsigned int numlower) return oe; } +static bool ovl_dentry_remote(struct dentry *dentry) +{ + return dentry->d_flags & + (DCACHE_OP_REVALIDATE | DCACHE_OP_WEAK_REVALIDATE); +} + +static bool ovl_dentry_weird(struct dentry *dentry) +{ + return dentry->d_flags & (DCACHE_NEED_AUTOMOUNT | + DCACHE_MANAGE_TRANSIT | + DCACHE_OP_HASH | + DCACHE_OP_COMPARE); +} + static inline struct dentry *ovl_lookup_real(struct dentry *dir, struct qstr *name) { @@ -303,6 +365,10 @@ static inline struct dentry *ovl_lookup_real(struct dentry *dir, } else if (!dentry->d_inode) { dput(dentry); dentry = NULL; + } else if (ovl_dentry_weird(dentry)) { + dput(dentry); + /* Don't support traversing automounts and other weirdness */ + dentry = ERR_PTR(-EREMOTE); } return dentry; } @@ -350,6 +416,11 @@ struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry, goto out; if (this) { + if (unlikely(ovl_dentry_remote(this))) { + dput(this); + err = -EREMOTE; + goto out; + } if (ovl_is_whiteout(this)) { dput(this); this = NULL; @@ -694,25 +765,6 @@ static void ovl_unescape(char *s) } } -static bool ovl_is_allowed_fs_type(struct dentry *root) -{ - const struct dentry_operations *dop = root->d_op; - - /* - * We don't support: - * - automount filesystems - * - filesystems with revalidate (FIXME for lower layer) - * - filesystems with case insensitive names - */ - if (dop && - (dop->d_manage || dop->d_automount || - dop->d_revalidate || dop->d_weak_revalidate || - dop->d_compare || dop->d_hash)) { - return false; - } - return true; -} - static int ovl_mount_dir_noesc(const char *name, struct path *path) { int err = -EINVAL; @@ -727,7 +779,7 @@ static int ovl_mount_dir_noesc(const char *name, struct path *path) goto out; } err = -EINVAL; - if (!ovl_is_allowed_fs_type(path->dentry)) { + if (ovl_dentry_weird(path->dentry)) { pr_err("overlayfs: filesystem on '%s' not supported\n", name); goto out_put; } @@ -751,13 +803,21 @@ static int ovl_mount_dir(const char *name, struct path *path) if (tmp) { ovl_unescape(tmp); err = ovl_mount_dir_noesc(tmp, path); + + if (!err) + if (ovl_dentry_remote(path->dentry)) { + pr_err("overlayfs: filesystem on '%s' not supported as upperdir\n", + tmp); + path_put(path); + err = -EINVAL; + } kfree(tmp); } return err; } static int ovl_lower_dir(const char *name, struct path *path, long *namelen, - int *stack_depth) + int *stack_depth, bool *remote) { int err; struct kstatfs statfs; @@ -774,6 +834,9 @@ static int ovl_lower_dir(const char *name, struct path *path, long *namelen, *namelen = max(*namelen, statfs.f_namelen); *stack_depth = max(*stack_depth, path->mnt->mnt_sb->s_stack_depth); + if (ovl_dentry_remote(path->dentry)) + *remote = true; + return 0; out_put: @@ -827,6 +890,7 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent) unsigned int numlower; unsigned int stacklen = 0; unsigned int i; + bool remote = false; int err; err = -ENOMEM; @@ -900,7 +964,8 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent) lower = lowertmp; for (numlower = 0; numlower < stacklen; numlower++) { err = ovl_lower_dir(lower, &stack[numlower], - &ufs->lower_namelen, &sb->s_stack_depth); + &ufs->lower_namelen, &sb->s_stack_depth, + &remote); if (err) goto out_put_lowerpath; @@ -958,7 +1023,10 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent) if (!ufs->upper_mnt) sb->s_flags |= MS_RDONLY; - sb->s_d_op = &ovl_dentry_operations; + if (remote) + sb->s_d_op = &ovl_reval_dentry_operations; + else + sb->s_d_op = &ovl_dentry_operations; err = -ENOMEM; oe = ovl_alloc_entry(numlower); -- cgit v1.2.3-54-g00ecf