diff options
Diffstat (limited to 'fs/overlayfs/super.c')
| -rw-r--r-- | fs/overlayfs/super.c | 920 |
1 files changed, 676 insertions, 244 deletions
diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c index ac967f1cb6e5..a29a8afe9b26 100644 --- a/fs/overlayfs/super.c +++ b/fs/overlayfs/super.c @@ -15,6 +15,7 @@ #include <linux/seq_file.h> #include <linux/posix_acl_xattr.h> #include <linux/exportfs.h> +#include <linux/file.h> #include "overlayfs.h" MODULE_AUTHOR("Miklos Szeredi <miklos@szeredi.hu>"); @@ -79,7 +80,7 @@ static void ovl_dentry_release(struct dentry *dentry) static struct dentry *ovl_d_real(struct dentry *dentry, const struct inode *inode) { - struct dentry *real; + struct dentry *real = NULL, *lower; /* It's an overlay file */ if (inode && d_inode(dentry) == inode) @@ -98,9 +99,10 @@ static struct dentry *ovl_d_real(struct dentry *dentry, if (real && !inode && ovl_has_upperdata(d_inode(dentry))) return real; - real = ovl_dentry_lowerdata(dentry); - if (!real) + lower = ovl_dentry_lowerdata(dentry); + if (!lower) goto bug; + real = lower; /* Handle recursion */ real = d_real(real, inode); @@ -108,58 +110,61 @@ static struct dentry *ovl_d_real(struct dentry *dentry, if (!inode || inode == d_inode(real)) return real; bug: - WARN(1, "ovl_d_real(%pd4, %s:%lu): real dentry not found\n", dentry, - inode ? inode->i_sb->s_id : "NULL", inode ? inode->i_ino : 0); + WARN(1, "%s(%pd4, %s:%lu): real dentry (%p/%lu) not found\n", + __func__, dentry, inode ? inode->i_sb->s_id : "NULL", + inode ? inode->i_ino : 0, real, + real && d_inode(real) ? d_inode(real)->i_ino : 0); return dentry; } -static int ovl_dentry_revalidate(struct dentry *dentry, unsigned int flags) +static int ovl_revalidate_real(struct dentry *d, unsigned int flags, bool weak) { - 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; - } + if (weak) { + if (d->d_flags & DCACHE_OP_WEAK_REVALIDATE) + ret = d->d_op->d_weak_revalidate(d, flags); + } else if (d->d_flags & DCACHE_OP_REVALIDATE) { + ret = d->d_op->d_revalidate(d, flags); + if (!ret) { + if (!(flags & LOOKUP_RCU)) + d_invalidate(d); + ret = -ESTALE; } } - return 1; + return ret; } -static int ovl_dentry_weak_revalidate(struct dentry *dentry, unsigned int flags) +static int ovl_dentry_revalidate_common(struct dentry *dentry, + unsigned int flags, bool weak) { struct ovl_entry *oe = dentry->d_fsdata; + struct dentry *upper; unsigned int i; int ret = 1; - for (i = 0; i < oe->numlower; i++) { - struct dentry *d = oe->lowerstack[i].dentry; + upper = ovl_dentry_upper(dentry); + if (upper) + ret = ovl_revalidate_real(upper, flags, weak); - if (d->d_flags & DCACHE_OP_WEAK_REVALIDATE) { - ret = d->d_op->d_weak_revalidate(d, flags); - if (ret <= 0) - break; - } + for (i = 0; ret > 0 && i < oe->numlower; i++) { + ret = ovl_revalidate_real(oe->lowerstack[i].dentry, flags, + weak); } return ret; } -static const struct dentry_operations ovl_dentry_operations = { - .d_release = ovl_dentry_release, - .d_real = ovl_d_real, -}; +static int ovl_dentry_revalidate(struct dentry *dentry, unsigned int flags) +{ + return ovl_dentry_revalidate_common(dentry, flags, false); +} + +static int ovl_dentry_weak_revalidate(struct dentry *dentry, unsigned int flags) +{ + return ovl_dentry_revalidate_common(dentry, flags, true); +} -static const struct dentry_operations ovl_reval_dentry_operations = { +static const struct dentry_operations ovl_dentry_operations = { .d_release = ovl_dentry_release, .d_real = ovl_d_real, .d_revalidate = ovl_dentry_revalidate, @@ -170,7 +175,7 @@ static struct kmem_cache *ovl_inode_cachep; static struct inode *ovl_alloc_inode(struct super_block *sb) { - struct ovl_inode *oi = kmem_cache_alloc(ovl_inode_cachep, GFP_KERNEL); + struct ovl_inode *oi = alloc_inode_sb(sb, ovl_inode_cachep, GFP_KERNEL); if (!oi) return NULL; @@ -180,7 +185,8 @@ static struct inode *ovl_alloc_inode(struct super_block *sb) oi->version = 0; oi->flags = 0; oi->__upperdentry = NULL; - oi->lower = NULL; + oi->lowerpath.dentry = NULL; + oi->lowerpath.layer = NULL; oi->lowerdata = NULL; mutex_init(&oi->lock); @@ -201,7 +207,7 @@ static void ovl_destroy_inode(struct inode *inode) struct ovl_inode *oi = OVL_I(inode); dput(oi->__upperdentry); - iput(oi->lower); + dput(oi->lowerpath.dentry); if (S_ISDIR(inode->i_mode)) ovl_dir_cache_free(inode); else @@ -210,24 +216,28 @@ static void ovl_destroy_inode(struct inode *inode) static void ovl_free_fs(struct ovl_fs *ofs) { + struct vfsmount **mounts; unsigned i; iput(ofs->workbasedir_trap); iput(ofs->indexdir_trap); iput(ofs->workdir_trap); - iput(ofs->upperdir_trap); + dput(ofs->whiteout); dput(ofs->indexdir); dput(ofs->workdir); if (ofs->workdir_locked) ovl_inuse_unlock(ofs->workbasedir); dput(ofs->workbasedir); if (ofs->upperdir_locked) - ovl_inuse_unlock(ofs->upper_mnt->mnt_root); - mntput(ofs->upper_mnt); - for (i = 1; i < ofs->numlayer; i++) { + ovl_inuse_unlock(ovl_upper_mnt(ofs)->mnt_root); + + /* Hack! Reuse ofs->layers as a vfsmount array before freeing it */ + mounts = (struct vfsmount **) ofs->layers; + for (i = 0; i < ofs->numlayer; i++) { iput(ofs->layers[i].trap); - mntput(ofs->layers[i].mnt); + mounts[i] = ofs->layers[i].mnt; } + kern_unmount_array(mounts, ofs->numlayer); kfree(ofs->layers); for (i = 0; i < ofs->numfs; i++) free_anon_bdev(ofs->fs[i].pseudo_dev); @@ -256,12 +266,23 @@ static int ovl_sync_fs(struct super_block *sb, int wait) struct super_block *upper_sb; int ret; - if (!ofs->upper_mnt) - return 0; + ret = ovl_sync_status(ofs); + /* + * We have to always set the err, because the return value isn't + * checked in syncfs, and instead indirectly return an error via + * the sb's writeback errseq, which VFS inspects after this call. + */ + if (ret < 0) { + errseq_set(&sb->s_wb_err, -EIO); + return -EIO; + } + + if (!ret) + return ret; /* - * If this is a sync(2) call or an emergency sync, all the super blocks - * will be iterated, including upper_sb, so no need to do anything. + * Not called for sync(2) call or an emergency sync (SB_I_SKIP_SYNC). + * All the super blocks will be iterated, including upper_sb. * * If this is a syncfs(2) call, then we do need to call * sync_filesystem() on upper_sb, but enough if we do it when being @@ -270,7 +291,7 @@ static int ovl_sync_fs(struct super_block *sb, int wait) if (!wait) return 0; - upper_sb = ofs->upper_mnt->mnt_sb; + upper_sb = ovl_upper_mnt(ofs)->mnt_sb; down_read(&upper_sb->s_umount); ret = sync_filesystem(upper_sb); @@ -281,7 +302,7 @@ static int ovl_sync_fs(struct super_block *sb, int wait) /** * ovl_statfs - * @sb: The overlayfs super block + * @dentry: The dentry to query * @buf: The struct kstatfs to fill in with stats * * Get the filesystem statistics. As writes always target the upper layer @@ -308,7 +329,7 @@ static int ovl_statfs(struct dentry *dentry, struct kstatfs *buf) /* Will this overlay be forced to mount/remount ro? */ static bool ovl_force_readonly(struct ovl_fs *ofs) { - return (!ofs->upper_mnt || !ofs->workdir); + return (!ovl_upper_mnt(ofs) || !ofs->workdir); } static const char *ovl_redirect_mode_def(void) @@ -316,12 +337,6 @@ static const char *ovl_redirect_mode_def(void) return ovl_redirect_dir_def ? "on" : "off"; } -enum { - OVL_XINO_OFF, - OVL_XINO_AUTO, - OVL_XINO_ON, -}; - static const char * const ovl_xino_str[] = { "off", "auto", @@ -335,6 +350,8 @@ static inline int ovl_xino_def(void) /** * ovl_show_options + * @m: the seq_file handle + * @dentry: The dentry to query * * Prints the mount options for a given superblock. * Returns zero; does not fail. @@ -355,6 +372,8 @@ static int ovl_show_options(struct seq_file *m, struct dentry *dentry) seq_printf(m, ",redirect_dir=%s", ofs->config.redirect_mode); if (ofs->config.index != ovl_index_def) seq_printf(m, ",index=%s", ofs->config.index ? "on" : "off"); + if (!ofs->config.uuid) + seq_puts(m, ",uuid=off"); if (ofs->config.nfs_export != ovl_nfs_export_def) seq_printf(m, ",nfs_export=%s", ofs->config.nfs_export ? "on" : "off"); @@ -363,17 +382,32 @@ static int ovl_show_options(struct seq_file *m, struct dentry *dentry) if (ofs->config.metacopy != ovl_metacopy_def) seq_printf(m, ",metacopy=%s", ofs->config.metacopy ? "on" : "off"); + if (ofs->config.ovl_volatile) + seq_puts(m, ",volatile"); + if (ofs->config.userxattr) + seq_puts(m, ",userxattr"); return 0; } static int ovl_remount(struct super_block *sb, int *flags, char *data) { struct ovl_fs *ofs = sb->s_fs_info; + struct super_block *upper_sb; + int ret = 0; if (!(*flags & SB_RDONLY) && ovl_force_readonly(ofs)) return -EROFS; - return 0; + if (*flags & SB_RDONLY && !sb_rdonly(sb)) { + upper_sb = ovl_upper_mnt(ofs)->mnt_sb; + if (ovl_should_sync(ofs)) { + down_read(&upper_sb->s_umount); + ret = sync_filesystem(upper_sb); + up_read(&upper_sb->s_umount); + } + } + + return ret; } static const struct super_operations ovl_super_operations = { @@ -396,13 +430,17 @@ enum { OPT_REDIRECT_DIR, OPT_INDEX_ON, OPT_INDEX_OFF, + OPT_UUID_ON, + OPT_UUID_OFF, OPT_NFS_EXPORT_ON, + OPT_USERXATTR, OPT_NFS_EXPORT_OFF, OPT_XINO_ON, OPT_XINO_OFF, OPT_XINO_AUTO, OPT_METACOPY_ON, OPT_METACOPY_OFF, + OPT_VOLATILE, OPT_ERR, }; @@ -414,6 +452,9 @@ static const match_table_t ovl_tokens = { {OPT_REDIRECT_DIR, "redirect_dir=%s"}, {OPT_INDEX_ON, "index=on"}, {OPT_INDEX_OFF, "index=off"}, + {OPT_USERXATTR, "userxattr"}, + {OPT_UUID_ON, "uuid=on"}, + {OPT_UUID_OFF, "uuid=off"}, {OPT_NFS_EXPORT_ON, "nfs_export=on"}, {OPT_NFS_EXPORT_OFF, "nfs_export=off"}, {OPT_XINO_ON, "xino=on"}, @@ -421,6 +462,7 @@ static const match_table_t ovl_tokens = { {OPT_XINO_AUTO, "xino=auto"}, {OPT_METACOPY_ON, "metacopy=on"}, {OPT_METACOPY_OFF, "metacopy=off"}, + {OPT_VOLATILE, "volatile"}, {OPT_ERR, NULL} }; @@ -475,6 +517,7 @@ static int ovl_parse_opt(char *opt, struct ovl_config *config) char *p; int err; bool metacopy_opt = false, redirect_opt = false; + bool nfs_export_opt = false, index_opt = false; config->redirect_mode = kstrdup(ovl_redirect_mode_def(), GFP_KERNEL); if (!config->redirect_mode) @@ -524,18 +567,30 @@ static int ovl_parse_opt(char *opt, struct ovl_config *config) case OPT_INDEX_ON: config->index = true; + index_opt = true; break; case OPT_INDEX_OFF: config->index = false; + index_opt = true; + break; + + case OPT_UUID_ON: + config->uuid = true; + break; + + case OPT_UUID_OFF: + config->uuid = false; break; case OPT_NFS_EXPORT_ON: config->nfs_export = true; + nfs_export_opt = true; break; case OPT_NFS_EXPORT_OFF: config->nfs_export = false; + nfs_export_opt = true; break; case OPT_XINO_ON: @@ -557,6 +612,15 @@ static int ovl_parse_opt(char *opt, struct ovl_config *config) case OPT_METACOPY_OFF: config->metacopy = false; + metacopy_opt = true; + break; + + case OPT_VOLATILE: + config->ovl_volatile = true; + break; + + case OPT_USERXATTR: + config->userxattr = true; break; default: @@ -566,12 +630,24 @@ static int ovl_parse_opt(char *opt, struct ovl_config *config) } } - /* Workdir is useless in non-upper mount */ - if (!config->upperdir && config->workdir) { - pr_info("option \"workdir=%s\" is useless in a non-upper mount, ignore\n", - config->workdir); - kfree(config->workdir); - config->workdir = NULL; + /* Workdir/index are useless in non-upper mount */ + if (!config->upperdir) { + if (config->workdir) { + pr_info("option \"workdir=%s\" is useless in a non-upper mount, ignore\n", + config->workdir); + kfree(config->workdir); + config->workdir = NULL; + } + if (config->index && index_opt) { + pr_info("option \"index=on\" is useless in a non-upper mount, ignore\n"); + index_opt = false; + } + config->index = false; + } + + if (!config->upperdir && config->ovl_volatile) { + pr_info("option \"volatile\" is meaningless in a non-upper mount, ignoring it.\n"); + config->ovl_volatile = false; } err = ovl_parse_redirect_mode(config, config->redirect_mode); @@ -606,6 +682,72 @@ static int ovl_parse_opt(char *opt, struct ovl_config *config) } } + /* Resolve nfs_export -> index dependency */ + if (config->nfs_export && !config->index) { + if (!config->upperdir && config->redirect_follow) { + pr_info("NFS export requires \"redirect_dir=nofollow\" on non-upper mount, falling back to nfs_export=off.\n"); + config->nfs_export = false; + } else if (nfs_export_opt && index_opt) { + pr_err("conflicting options: nfs_export=on,index=off\n"); + return -EINVAL; + } else if (index_opt) { + /* + * There was an explicit index=off that resulted + * in this conflict. + */ + pr_info("disabling nfs_export due to index=off\n"); + config->nfs_export = false; + } else { + /* Automatically enable index otherwise. */ + config->index = true; + } + } + + /* Resolve nfs_export -> !metacopy dependency */ + if (config->nfs_export && config->metacopy) { + if (nfs_export_opt && metacopy_opt) { + pr_err("conflicting options: nfs_export=on,metacopy=on\n"); + return -EINVAL; + } + if (metacopy_opt) { + /* + * There was an explicit metacopy=on that resulted + * in this conflict. + */ + pr_info("disabling nfs_export due to metacopy=on\n"); + config->nfs_export = false; + } else { + /* + * There was an explicit nfs_export=on that resulted + * in this conflict. + */ + pr_info("disabling metacopy due to nfs_export=on\n"); + config->metacopy = false; + } + } + + + /* Resolve userxattr -> !redirect && !metacopy dependency */ + if (config->userxattr) { + if (config->redirect_follow && redirect_opt) { + pr_err("conflicting options: userxattr,redirect_dir=%s\n", + config->redirect_mode); + return -EINVAL; + } + if (config->metacopy && metacopy_opt) { + pr_err("conflicting options: userxattr,metacopy=on\n"); + return -EINVAL; + } + /* + * Silently disable default setting of redirect and metacopy. + * This shall be the default in the future as well: these + * options must be explicitly enabled if used together with + * userxattr. + */ + config->redirect_dir = config->redirect_follow = false; + config->metacopy = false; + } + return 0; } @@ -616,17 +758,14 @@ static struct dentry *ovl_workdir_create(struct ovl_fs *ofs, const char *name, bool persist) { struct inode *dir = ofs->workbasedir->d_inode; - struct vfsmount *mnt = ofs->upper_mnt; + struct vfsmount *mnt = ovl_upper_mnt(ofs); struct dentry *work; int err; bool retried = false; - bool locked = false; inode_lock_nested(dir, I_MUTEX_PARENT); - locked = true; - retry: - work = lookup_one_len(name, ofs->workbasedir, strlen(name)); + work = ovl_lookup_upper(ofs, name, ofs->workbasedir, strlen(name)); if (!IS_ERR(work)) { struct iattr attr = { @@ -643,15 +782,23 @@ retry: goto out_unlock; retried = true; - ovl_workdir_cleanup(dir, mnt, work, 0); + err = ovl_workdir_cleanup(ofs, dir, mnt, work, 0); dput(work); + if (err == -EINVAL) { + work = ERR_PTR(err); + goto out_unlock; + } goto retry; } - work = ovl_create_real(dir, work, OVL_CATTR(attr.ia_mode)); - err = PTR_ERR(work); - if (IS_ERR(work)) - goto out_err; + err = ovl_mkdir_real(ofs, dir, &work, attr.ia_mode); + if (err) + goto out_dput; + + /* Weird filesystem returning with hashed negative (kernfs)? */ + err = -EINVAL; + if (d_really_is_negative(work)) + goto out_dput; /* * Try to remove POSIX ACL xattrs from workdir. We are good if: @@ -666,17 +813,19 @@ retry: * allowed as upper are limited to "normal" ones, where checking * for the above two errors is sufficient. */ - err = vfs_removexattr(work, XATTR_NAME_POSIX_ACL_DEFAULT); + err = ovl_do_removexattr(ofs, work, + XATTR_NAME_POSIX_ACL_DEFAULT); if (err && err != -ENODATA && err != -EOPNOTSUPP) goto out_dput; - err = vfs_removexattr(work, XATTR_NAME_POSIX_ACL_ACCESS); + err = ovl_do_removexattr(ofs, work, + XATTR_NAME_POSIX_ACL_ACCESS); if (err && err != -ENODATA && err != -EOPNOTSUPP) goto out_dput; /* Clear any inherited mode bits */ inode_lock(work->d_inode); - err = notify_change(work, &attr, NULL); + err = ovl_do_notify_change(ofs, work, &attr); inode_unlock(work->d_inode); if (err) goto out_dput; @@ -685,9 +834,7 @@ retry: goto out_err; } out_unlock: - if (locked) - inode_unlock(dir); - + inode_unlock(dir); return work; out_dput: @@ -751,19 +898,18 @@ static int ovl_mount_dir(const char *name, struct path *path) ovl_unescape(tmp); err = ovl_mount_dir_noesc(tmp, path); - if (!err) - if (ovl_dentry_remote(path->dentry)) { - pr_err("filesystem on '%s' not supported as upperdir\n", - tmp); - path_put_init(path); - err = -EINVAL; - } + if (!err && path->dentry->d_flags & DCACHE_OP_REAL) { + pr_err("filesystem on '%s' not supported as upperdir\n", + tmp); + path_put_init(path); + err = -EINVAL; + } kfree(tmp); } return err; } -static int ovl_check_namelen(struct path *path, struct ovl_fs *ofs, +static int ovl_check_namelen(const struct path *path, struct ovl_fs *ofs, const char *name) { struct kstatfs statfs; @@ -778,24 +924,21 @@ static int ovl_check_namelen(struct path *path, struct ovl_fs *ofs, } static int ovl_lower_dir(const char *name, struct path *path, - struct ovl_fs *ofs, int *stack_depth, bool *remote) + struct ovl_fs *ofs, int *stack_depth) { int fh_type; int err; err = ovl_mount_dir_noesc(name, path); if (err) - goto out; + return err; err = ovl_check_namelen(path, ofs, name); if (err) - goto out_put; + return err; *stack_depth = max(*stack_depth, path->mnt->mnt_sb->s_stack_depth); - if (ovl_dentry_remote(path->dentry)) - *remote = true; - /* * The inodes index feature and NFS export need to encode and decode * file handles, so they require that all layers support them. @@ -808,17 +951,22 @@ static int ovl_lower_dir(const char *name, struct path *path, pr_warn("fs on '%s' does not support file handles, falling back to index=off,nfs_export=off.\n", name); } + /* + * Decoding origin file handle is required for persistent st_ino. + * Without persistent st_ino, xino=auto falls back to xino=off. + */ + if (ofs->config.xino == OVL_XINO_AUTO && + ofs->config.upperdir && !fh_type) { + ofs->config.xino = OVL_XINO_OFF; + pr_warn("fs on '%s' does not support file handles, falling back to xino=off.\n", + name); + } /* Check if lower fs has 32bit inode numbers */ if (fh_type != FILEID_INO32_GEN) ofs->xino_mode = -1; return 0; - -out_put: - path_put_init(path); -out: - return err; } /* Workdir should not be subdir of upperdir and vice versa */ @@ -863,6 +1011,7 @@ ovl_posix_acl_xattr_get(const struct xattr_handler *handler, static int __maybe_unused ovl_posix_acl_xattr_set(const struct xattr_handler *handler, + struct user_namespace *mnt_userns, struct dentry *dentry, struct inode *inode, const char *name, const void *value, size_t size, int flags) @@ -874,7 +1023,20 @@ ovl_posix_acl_xattr_set(const struct xattr_handler *handler, /* Check that everything is OK before copy-up */ if (value) { - acl = posix_acl_from_xattr(&init_user_ns, value, size); + /* The above comment can be understood in two ways: + * + * 1. We just want to check whether the basic POSIX ACL format + * is ok. For example, if the header is correct and the size + * is sane. + * 2. We want to know whether the ACL_{GROUP,USER} entries can + * be mapped according to the underlying filesystem. + * + * Currently, we only check 1. If we wanted to check 2. we + * would need to pass the mnt_userns and the fs_userns of the + * underlying filesystem. But frankly, I think checking 1. is + * enough to start the copy-up. + */ + acl = vfs_set_acl_prepare(&init_user_ns, &init_user_ns, value, size); if (IS_ERR(acl)) return PTR_ERR(acl); } @@ -888,7 +1050,7 @@ ovl_posix_acl_xattr_set(const struct xattr_handler *handler, goto out_acl_release; } err = -EPERM; - if (!inode_owner_or_capable(inode)) + if (!inode_owner_or_capable(&init_user_ns, inode)) goto out_acl_release; posix_acl_release(acl); @@ -900,18 +1062,15 @@ ovl_posix_acl_xattr_set(const struct xattr_handler *handler, if (unlikely(inode->i_mode & S_ISGID) && handler->flags == ACL_TYPE_ACCESS && !in_group_p(inode->i_gid) && - !capable_wrt_inode_uidgid(inode, CAP_FSETID)) { + !capable_wrt_inode_uidgid(&init_user_ns, inode, CAP_FSETID)) { struct iattr iattr = { .ia_valid = ATTR_KILL_SGID }; - err = ovl_setattr(dentry, &iattr); + err = ovl_setattr(&init_user_ns, dentry, &iattr); if (err) return err; } err = ovl_xattr_set(dentry, inode, handler->name, value, size, flags); - if (!err) - ovl_copyattr(ovl_inode_real(inode), inode); - return err; out_acl_release: @@ -927,6 +1086,7 @@ static int ovl_own_xattr_get(const struct xattr_handler *handler, } static int ovl_own_xattr_set(const struct xattr_handler *handler, + struct user_namespace *mnt_userns, struct dentry *dentry, struct inode *inode, const char *name, const void *value, size_t size, int flags) @@ -942,6 +1102,7 @@ static int ovl_other_xattr_get(const struct xattr_handler *handler, } static int ovl_other_xattr_set(const struct xattr_handler *handler, + struct user_namespace *mnt_userns, struct dentry *dentry, struct inode *inode, const char *name, const void *value, size_t size, int flags) @@ -965,8 +1126,14 @@ ovl_posix_acl_default_xattr_handler = { .set = ovl_posix_acl_xattr_set, }; -static const struct xattr_handler ovl_own_xattr_handler = { - .prefix = OVL_XATTR_PREFIX, +static const struct xattr_handler ovl_own_trusted_xattr_handler = { + .prefix = OVL_XATTR_TRUSTED_PREFIX, + .get = ovl_own_xattr_get, + .set = ovl_own_xattr_set, +}; + +static const struct xattr_handler ovl_own_user_xattr_handler = { + .prefix = OVL_XATTR_USER_PREFIX, .get = ovl_own_xattr_get, .set = ovl_own_xattr_set, }; @@ -977,12 +1144,22 @@ static const struct xattr_handler ovl_other_xattr_handler = { .set = ovl_other_xattr_set, }; -static const struct xattr_handler *ovl_xattr_handlers[] = { +static const struct xattr_handler *ovl_trusted_xattr_handlers[] = { #ifdef CONFIG_FS_POSIX_ACL &ovl_posix_acl_access_xattr_handler, &ovl_posix_acl_default_xattr_handler, #endif - &ovl_own_xattr_handler, + &ovl_own_trusted_xattr_handler, + &ovl_other_xattr_handler, + NULL +}; + +static const struct xattr_handler *ovl_user_xattr_handlers[] = { +#ifdef CONFIG_FS_POSIX_ACL + &ovl_posix_acl_access_xattr_handler, + &ovl_posix_acl_default_xattr_handler, +#endif + &ovl_own_user_xattr_handler, &ovl_other_xattr_handler, NULL }; @@ -1025,7 +1202,7 @@ static int ovl_report_in_use(struct ovl_fs *ofs, const char *name) } static int ovl_get_upper(struct super_block *sb, struct ovl_fs *ofs, - struct path *upperpath) + struct ovl_layer *upper_layer, struct path *upperpath) { struct vfsmount *upper_mnt; int err; @@ -1034,8 +1211,8 @@ static int ovl_get_upper(struct super_block *sb, struct ovl_fs *ofs, if (err) goto out; - /* Upper fs should not be r/o */ - if (sb_rdonly(upperpath->mnt->mnt_sb)) { + /* Upperdir path should not be r/o */ + if (__mnt_is_readonly(upperpath->mnt)) { pr_err("upper fs is r/o, try multi-lower layers mount\n"); err = -EINVAL; goto out; @@ -1045,7 +1222,7 @@ static int ovl_get_upper(struct super_block *sb, struct ovl_fs *ofs, if (err) goto out; - err = ovl_setup_trap(sb, upperpath->dentry, &ofs->upperdir_trap, + err = ovl_setup_trap(sb, upperpath->dentry, &upper_layer->trap, "upperdir"); if (err) goto out; @@ -1059,9 +1236,23 @@ static int ovl_get_upper(struct super_block *sb, struct ovl_fs *ofs, /* Don't inherit atime flags */ upper_mnt->mnt_flags &= ~(MNT_NOATIME | MNT_NODIRATIME | MNT_RELATIME); - ofs->upper_mnt = upper_mnt; + upper_layer->mnt = upper_mnt; + upper_layer->idx = 0; + upper_layer->fsid = 0; + + /* + * Inherit SB_NOSEC flag from upperdir. + * + * This optimization changes behavior when a security related attribute + * (suid/sgid/security.*) is changed on an underlying layer. This is + * okay because we don't yet have guarantees in that case, but it will + * need careful treatment once we want to honour changes to underlying + * filesystems. + */ + if (upper_mnt->mnt_sb->s_flags & SB_NOSEC) + sb->s_flags |= SB_NOSEC; - if (ovl_inuse_trylock(ofs->upper_mnt->mnt_root)) { + if (ovl_inuse_trylock(ovl_upper_mnt(ofs)->mnt_root)) { ofs->upperdir_locked = true; } else { err = ovl_report_in_use(ofs, "upperdir"); @@ -1074,11 +1265,115 @@ out: return err; } -static int ovl_make_workdir(struct super_block *sb, struct ovl_fs *ofs, - struct path *workpath) +/* + * Returns 1 if RENAME_WHITEOUT is supported, 0 if not supported and + * negative values if error is encountered. + */ +static int ovl_check_rename_whiteout(struct ovl_fs *ofs) { - struct vfsmount *mnt = ofs->upper_mnt; + struct dentry *workdir = ofs->workdir; + struct inode *dir = d_inode(workdir); struct dentry *temp; + struct dentry *dest; + struct dentry *whiteout; + struct name_snapshot name; + int err; + + inode_lock_nested(dir, I_MUTEX_PARENT); + + temp = ovl_create_temp(ofs, workdir, OVL_CATTR(S_IFREG | 0)); + err = PTR_ERR(temp); + if (IS_ERR(temp)) + goto out_unlock; + + dest = ovl_lookup_temp(ofs, workdir); + err = PTR_ERR(dest); + if (IS_ERR(dest)) { + dput(temp); + goto out_unlock; + } + + /* Name is inline and stable - using snapshot as a copy helper */ + take_dentry_name_snapshot(&name, temp); + err = ovl_do_rename(ofs, dir, temp, dir, dest, RENAME_WHITEOUT); + if (err) { + if (err == -EINVAL) + err = 0; + goto cleanup_temp; + } + + whiteout = ovl_lookup_upper(ofs, name.name.name, workdir, name.name.len); + err = PTR_ERR(whiteout); + if (IS_ERR(whiteout)) + goto cleanup_temp; + + err = ovl_is_whiteout(whiteout); + + /* Best effort cleanup of whiteout and temp file */ + if (err) + ovl_cleanup(ofs, dir, whiteout); + dput(whiteout); + +cleanup_temp: + ovl_cleanup(ofs, dir, temp); + release_dentry_name_snapshot(&name); + dput(temp); + dput(dest); + +out_unlock: + inode_unlock(dir); + + return err; +} + +static struct dentry *ovl_lookup_or_create(struct ovl_fs *ofs, + struct dentry *parent, + const char *name, umode_t mode) +{ + size_t len = strlen(name); + struct dentry *child; + + inode_lock_nested(parent->d_inode, I_MUTEX_PARENT); + child = ovl_lookup_upper(ofs, name, parent, len); + if (!IS_ERR(child) && !child->d_inode) + child = ovl_create_real(ofs, parent->d_inode, child, + OVL_CATTR(mode)); + inode_unlock(parent->d_inode); + dput(parent); + + return child; +} + +/* + * Creates $workdir/work/incompat/volatile/dirty file if it is not already + * present. + */ +static int ovl_create_volatile_dirty(struct ovl_fs *ofs) +{ + unsigned int ctr; + struct dentry *d = dget(ofs->workbasedir); + static const char *const volatile_path[] = { + OVL_WORKDIR_NAME, "incompat", "volatile", "dirty" + }; + const char *const *name = volatile_path; + + for (ctr = ARRAY_SIZE(volatile_path); ctr; ctr--, name++) { + d = ovl_lookup_or_create(ofs, d, *name, ctr > 1 ? S_IFDIR : S_IFREG); + if (IS_ERR(d)) + return PTR_ERR(d); + } + dput(d); + return 0; +} + +static int ovl_make_workdir(struct super_block *sb, struct ovl_fs *ofs, + const struct path *workpath) +{ + struct vfsmount *mnt = ovl_upper_mnt(ofs); + struct dentry *workdir; + struct file *tmpfile; + bool rename_whiteout; + bool d_type; int fh_type; int err; @@ -1086,10 +1381,13 @@ static int ovl_make_workdir(struct super_block *sb, struct ovl_fs *ofs, if (err) return err; - ofs->workdir = ovl_workdir_create(ofs, OVL_WORKDIR_NAME, false); - if (!ofs->workdir) + workdir = ovl_workdir_create(ofs, OVL_WORKDIR_NAME, false); + err = PTR_ERR(workdir); + if (IS_ERR_OR_NULL(workdir)) goto out; + ofs->workdir = workdir; + err = ovl_setup_trap(sb, ofs->workdir, &ofs->workdir_trap, "workdir"); if (err) goto out; @@ -1104,33 +1402,77 @@ static int ovl_make_workdir(struct super_block *sb, struct ovl_fs *ofs, if (err < 0) goto out; - /* - * We allowed this configuration and don't want to break users over - * kernel upgrade. So warn instead of erroring out. - */ - if (!err) + d_type = err; + if (!d_type) pr_warn("upper fs needs to support d_type.\n"); /* Check if upper/work fs supports O_TMPFILE */ - temp = ovl_do_tmpfile(ofs->workdir, S_IFREG | 0); - ofs->tmpfile = !IS_ERR(temp); + tmpfile = ovl_do_tmpfile(ofs, ofs->workdir, S_IFREG | 0); + ofs->tmpfile = !IS_ERR(tmpfile); if (ofs->tmpfile) - dput(temp); + fput(tmpfile); else pr_warn("upper fs does not support tmpfile.\n"); + + /* Check if upper/work fs supports RENAME_WHITEOUT */ + err = ovl_check_rename_whiteout(ofs); + if (err < 0) + goto out; + + rename_whiteout = err; + if (!rename_whiteout) + pr_warn("upper fs does not support RENAME_WHITEOUT.\n"); + /* - * Check if upper/work fs supports trusted.overlay.* xattr + * Check if upper/work fs supports (trusted|user).overlay.* xattr */ - err = ovl_do_setxattr(ofs->workdir, OVL_XATTR_OPAQUE, "0", 1, 0); + err = ovl_setxattr(ofs, ofs->workdir, OVL_XATTR_OPAQUE, "0", 1); if (err) { + pr_warn("failed to set xattr on upper\n"); ofs->noxattr = true; - ofs->config.index = false; - ofs->config.metacopy = false; - pr_warn("upper fs does not support xattr, falling back to index=off and metacopy=off.\n"); + if (ofs->config.index || ofs->config.metacopy) { + ofs->config.index = false; + ofs->config.metacopy = false; + pr_warn("...falling back to index=off,metacopy=off.\n"); + } + /* + * xattr support is required for persistent st_ino. + * Without persistent st_ino, xino=auto falls back to xino=off. + */ + if (ofs->config.xino == OVL_XINO_AUTO) { + ofs->config.xino = OVL_XINO_OFF; + pr_warn("...falling back to xino=off.\n"); + } + if (err == -EPERM && !ofs->config.userxattr) + pr_info("try mounting with 'userxattr' option\n"); err = 0; } else { - vfs_removexattr(ofs->workdir, OVL_XATTR_OPAQUE); + ovl_removexattr(ofs, ofs->workdir, OVL_XATTR_OPAQUE); + } + + /* + * We allowed sub-optimal upper fs configuration and don't want to break + * users over kernel upgrade, but we never allowed remote upper fs, so + * we can enforce strict requirements for remote upper fs. + */ + if (ovl_dentry_remote(ofs->workdir) && + (!d_type || !rename_whiteout || ofs->noxattr)) { + pr_err("upper fs missing required features.\n"); + err = -EINVAL; + goto out; + } + + /* + * For volatile mount, create a incompat/volatile/dirty file to keep + * track of it. + */ + if (ofs->config.ovl_volatile) { + err = ovl_create_volatile_dirty(ofs); + if (err < 0) { + pr_err("Failed to create volatile/dirty file.\n"); + goto out; + } } /* Check if upper/work fs supports file handles */ @@ -1155,7 +1497,7 @@ out: } static int ovl_get_workdir(struct super_block *sb, struct ovl_fs *ofs, - struct path *upperpath) + const struct path *upperpath) { int err; struct path workpath = { }; @@ -1198,9 +1540,10 @@ out: } static int ovl_get_indexdir(struct super_block *sb, struct ovl_fs *ofs, - struct ovl_entry *oe, struct path *upperpath) + struct ovl_entry *oe, const struct path *upperpath) { - struct vfsmount *mnt = ofs->upper_mnt; + struct vfsmount *mnt = ovl_upper_mnt(ofs); + struct dentry *indexdir; int err; err = mnt_want_write(mnt); @@ -1208,15 +1551,25 @@ static int ovl_get_indexdir(struct super_block *sb, struct ovl_fs *ofs, return err; /* Verify lower root is upper root origin */ - err = ovl_verify_origin(upperpath->dentry, oe->lowerstack[0].dentry, - true); + err = ovl_verify_origin(ofs, upperpath->dentry, + oe->lowerstack[0].dentry, true); if (err) { pr_err("failed to verify upper root origin\n"); goto out; } - ofs->indexdir = ovl_workdir_create(ofs, OVL_INDEXDIR_NAME, true); - if (ofs->indexdir) { + /* index dir will act also as workdir */ + iput(ofs->workdir_trap); + ofs->workdir_trap = NULL; + dput(ofs->workdir); + ofs->workdir = NULL; + indexdir = ovl_workdir_create(ofs, OVL_INDEXDIR_NAME, true); + if (IS_ERR(indexdir)) { + err = PTR_ERR(indexdir); + } else if (indexdir) { + ofs->indexdir = indexdir; + ofs->workdir = dget(indexdir); + err = ovl_setup_trap(sb, ofs->indexdir, &ofs->indexdir_trap, "indexdir"); if (err) @@ -1224,19 +1577,21 @@ static int ovl_get_indexdir(struct super_block *sb, struct ovl_fs *ofs, /* * Verify upper root is exclusively associated with index dir. - * Older kernels stored upper fh in "trusted.overlay.origin" + * Older kernels stored upper fh in ".overlay.origin" * xattr. If that xattr exists, verify that it is a match to * upper dir file handle. In any case, verify or set xattr - * "trusted.overlay.upper" to indicate that index may have + * ".overlay.upper" to indicate that index may have * directory entries. */ - if (ovl_check_origin_xattr(ofs->indexdir)) { - err = ovl_verify_set_fh(ofs->indexdir, OVL_XATTR_ORIGIN, + if (ovl_check_origin_xattr(ofs, ofs->indexdir)) { + err = ovl_verify_set_fh(ofs, ofs->indexdir, + OVL_XATTR_ORIGIN, upperpath->dentry, true, false); if (err) pr_err("failed to verify index dir 'origin' xattr\n"); } - err = ovl_verify_upper(ofs->indexdir, upperpath->dentry, true); + err = ovl_verify_upper(ofs, ofs->indexdir, upperpath->dentry, + true); if (err) pr_err("failed to verify index dir 'upper' xattr\n"); @@ -1256,9 +1611,20 @@ static bool ovl_lower_uuid_ok(struct ovl_fs *ofs, const uuid_t *uuid) { unsigned int i; - if (!ofs->config.nfs_export && !ofs->upper_mnt) + if (!ofs->config.nfs_export && !ovl_upper_mnt(ofs)) return true; + /* + * We allow using single lower with null uuid for index and nfs_export + * for example to support those features with single lower squashfs. + * To avoid regressions in setups of overlay with re-formatted lower + * squashfs, do not allow decoding origin with lower null uuid unless + * user opted-in to one of the new features that require following the + * lower inode of non-dir upper. + */ + if (ovl_allow_offline_changes(ofs) && uuid_is_null(uuid)) + return false; + for (i = 0; i < ofs->numfs; i++) { /* * We use uuid to associate an overlay lower file handle with a @@ -1284,6 +1650,7 @@ static int ovl_get_fsid(struct ovl_fs *ofs, const struct path *path) dev_t dev; int err; bool bad_uuid = false; + bool warn = false; for (i = 0; i < ofs->numfs; i++) { if (ofs->fs[i].sb == sb) @@ -1292,13 +1659,20 @@ static int ovl_get_fsid(struct ovl_fs *ofs, const struct path *path) if (!ovl_lower_uuid_ok(ofs, &sb->s_uuid)) { bad_uuid = true; + if (ofs->config.xino == OVL_XINO_AUTO) { + ofs->config.xino = OVL_XINO_OFF; + warn = true; + } if (ofs->config.index || ofs->config.nfs_export) { ofs->config.index = false; ofs->config.nfs_export = false; - pr_warn("%s uuid detected in lower fs '%pd2', falling back to index=off,nfs_export=off.\n", + warn = true; + } + if (warn) { + pr_warn("%s uuid detected in lower fs '%pd2', falling back to xino=%s,index=off,nfs_export=off.\n", uuid_is_null(&sb->s_uuid) ? "null" : "conflicting", - path->dentry); + path->dentry, ovl_xino_str[ofs->config.xino]); } } @@ -1316,18 +1690,13 @@ static int ovl_get_fsid(struct ovl_fs *ofs, const struct path *path) } static int ovl_get_layers(struct super_block *sb, struct ovl_fs *ofs, - struct path *stack, unsigned int numlower) + struct path *stack, unsigned int numlower, + struct ovl_layer *layers) { int err; unsigned int i; - struct ovl_layer *layers; err = -ENOMEM; - layers = kcalloc(numlower + 1, sizeof(struct ovl_layer), GFP_KERNEL); - if (!layers) - goto out; - ofs->layers = layers; - ofs->fs = kcalloc(numlower + 1, sizeof(struct ovl_sb), GFP_KERNEL); if (ofs->fs == NULL) goto out; @@ -1335,11 +1704,6 @@ static int ovl_get_layers(struct super_block *sb, struct ovl_fs *ofs, /* idx/fsid 0 are reserved for upper fs even with lower only overlay */ ofs->numfs++; - layers[0].mnt = ofs->upper_mnt; - layers[0].idx = 0; - layers[0].fsid = 0; - ofs->numlayer = 1; - /* * All lower layers that share the same fs as upper layer, use the same * pseudo_dev as upper layer. Allocate fs[0].pseudo_dev even for lower @@ -1352,8 +1716,8 @@ static int ovl_get_layers(struct super_block *sb, struct ovl_fs *ofs, goto out; } - if (ofs->upper_mnt) { - ofs->fs[0].sb = ofs->upper_mnt->mnt_sb; + if (ovl_upper_mnt(ofs)) { + ofs->fs[0].sb = ovl_upper_mnt(ofs)->mnt_sb; ofs->fs[0].is_lower = false; } @@ -1366,14 +1730,23 @@ static int ovl_get_layers(struct super_block *sb, struct ovl_fs *ofs, if (err < 0) goto out; + /* + * Check if lower root conflicts with this overlay layers before + * checking if it is in-use as upperdir/workdir of "another" + * mount, because we do not bother to check in ovl_is_inuse() if + * the upperdir/workdir is in fact in-use by our + * upperdir/workdir. + */ err = ovl_setup_trap(sb, stack[i].dentry, &trap, "lowerdir"); if (err) goto out; if (ovl_is_inuse(stack[i].dentry)) { err = ovl_report_in_use(ofs, "lowerdir"); - if (err) + if (err) { + iput(trap); goto out; + } } mnt = clone_private_mount(&stack[i]); @@ -1401,26 +1774,29 @@ static int ovl_get_layers(struct super_block *sb, struct ovl_fs *ofs, /* * When all layers on same fs, overlay can use real inode numbers. - * With mount option "xino=on", mounter declares that there are enough - * free high bits in underlying fs to hold the unique fsid. + * With mount option "xino=<on|auto>", mounter declares that there are + * enough free high bits in underlying fs to hold the unique fsid. * If overlayfs does encounter underlying inodes using the high xino * bits reserved for fsid, it emits a warning and uses the original - * inode number. + * inode number or a non persistent inode number allocated from a + * dedicated range. */ - if (ofs->numfs - !ofs->upper_mnt == 1) { + if (ofs->numfs - !ovl_upper_mnt(ofs) == 1) { if (ofs->config.xino == OVL_XINO_ON) pr_info("\"xino=on\" is useless with all layers on same fs, ignore.\n"); ofs->xino_mode = 0; } else if (ofs->config.xino == OVL_XINO_OFF) { ofs->xino_mode = -1; - } else if (ofs->config.xino == OVL_XINO_ON && ofs->xino_mode < 0) { + } else if (ofs->xino_mode < 0) { /* * This is a roundup of number of bits needed for encoding - * fsid, where fsid 0 is reserved for upper fs even with - * lower only overlay. + * fsid, where fsid 0 is reserved for upper fs (even with + * lower only overlay) +1 extra bit is reserved for the non + * persistent inode number range that is used for resolving + * xino lower bits overflow. */ - BUILD_BUG_ON(ilog2(OVL_MAX_STACK) > 31); - ofs->xino_mode = ilog2(ofs->numfs - 1) + 1; + BUILD_BUG_ON(ilog2(OVL_MAX_STACK) > 30); + ofs->xino_mode = ilog2(ofs->numfs - 1) + 2; } if (ofs->xino_mode > 0) { @@ -1434,45 +1810,26 @@ out: } static struct ovl_entry *ovl_get_lowerstack(struct super_block *sb, - struct ovl_fs *ofs) + const char *lower, unsigned int numlower, + struct ovl_fs *ofs, struct ovl_layer *layers) { int err; - char *lowertmp, *lower; struct path *stack = NULL; - unsigned int stacklen, numlower = 0, i; - bool remote = false; + unsigned int i; struct ovl_entry *oe; - err = -ENOMEM; - lowertmp = kstrdup(ofs->config.lowerdir, GFP_KERNEL); - if (!lowertmp) - goto out_err; - - err = -EINVAL; - stacklen = ovl_split_lowerdirs(lowertmp); - if (stacklen > OVL_MAX_STACK) { - pr_err("too many lower directories, limit is %d\n", - OVL_MAX_STACK); - goto out_err; - } else if (!ofs->config.upperdir && stacklen == 1) { + if (!ofs->config.upperdir && numlower == 1) { pr_err("at least 2 lowerdir are needed while upperdir nonexistent\n"); - goto out_err; - } else if (!ofs->config.upperdir && ofs->config.nfs_export && - ofs->config.redirect_follow) { - pr_warn("NFS export requires \"redirect_dir=nofollow\" on non-upper mount, falling back to nfs_export=off.\n"); - ofs->config.nfs_export = false; + return ERR_PTR(-EINVAL); } - err = -ENOMEM; - stack = kcalloc(stacklen, sizeof(struct path), GFP_KERNEL); + stack = kcalloc(numlower, sizeof(struct path), GFP_KERNEL); if (!stack) - goto out_err; + return ERR_PTR(-ENOMEM); err = -EINVAL; - lower = lowertmp; - for (numlower = 0; numlower < stacklen; numlower++) { - err = ovl_lower_dir(lower, &stack[numlower], ofs, - &sb->s_stack_depth, &remote); + for (i = 0; i < numlower; i++) { + err = ovl_lower_dir(lower, &stack[i], ofs, &sb->s_stack_depth); if (err) goto out_err; @@ -1486,7 +1843,7 @@ static struct ovl_entry *ovl_get_lowerstack(struct super_block *sb, goto out_err; } - err = ovl_get_layers(sb, ofs, stack, numlower); + err = ovl_get_layers(sb, ofs, stack, numlower, layers); if (err) goto out_err; @@ -1500,16 +1857,10 @@ static struct ovl_entry *ovl_get_lowerstack(struct super_block *sb, oe->lowerstack[i].layer = &ofs->layers[i+1]; } - if (remote) - sb->s_d_op = &ovl_reval_dentry_operations; - else - sb->s_d_op = &ovl_dentry_operations; - out: for (i = 0; i < numlower; i++) path_put(&stack[i]); kfree(stack); - kfree(lowertmp); return oe; @@ -1524,7 +1875,8 @@ out_err: * - upper/work dir of any overlayfs instance */ static int ovl_check_layer(struct super_block *sb, struct ovl_fs *ofs, - struct dentry *dentry, const char *name) + struct dentry *dentry, const char *name, + bool is_lower) { struct dentry *next = dentry, *parent; int err = 0; @@ -1536,7 +1888,7 @@ static int ovl_check_layer(struct super_block *sb, struct ovl_fs *ofs, /* Walk back ancestors to root (inclusive) looking for traps */ while (!err && parent != next) { - if (ovl_lookup_trap_inode(sb, parent)) { + if (is_lower && ovl_lookup_trap_inode(sb, parent)) { err = -ELOOP; pr_err("overlapping %s path\n", name); } else if (ovl_is_inuse(parent)) { @@ -1560,9 +1912,9 @@ static int ovl_check_overlapping_layers(struct super_block *sb, { int i, err; - if (ofs->upper_mnt) { - err = ovl_check_layer(sb, ofs, ofs->upper_mnt->mnt_root, - "upperdir"); + if (ovl_upper_mnt(ofs)) { + err = ovl_check_layer(sb, ofs, ovl_upper_mnt(ofs)->mnt_root, + "upperdir", false); if (err) return err; @@ -1573,7 +1925,8 @@ static int ovl_check_overlapping_layers(struct super_block *sb, * workbasedir. In that case, we already have their traps in * inode cache and we will catch that case on lookup. */ - err = ovl_check_layer(sb, ofs, ofs->workbasedir, "workdir"); + err = ovl_check_layer(sb, ofs, ofs->workbasedir, "workdir", + false); if (err) return err; } @@ -1581,7 +1934,7 @@ static int ovl_check_overlapping_layers(struct super_block *sb, for (i = 1; i < ofs->numlayer; i++) { err = ovl_check_layer(sb, ofs, ofs->layers[i].mnt->mnt_root, - "lowerdir"); + "lowerdir", true); if (err) return err; } @@ -1589,25 +1942,77 @@ static int ovl_check_overlapping_layers(struct super_block *sb, return 0; } +static struct dentry *ovl_get_root(struct super_block *sb, + struct dentry *upperdentry, + struct ovl_entry *oe) +{ + struct dentry *root; + struct ovl_path *lowerpath = &oe->lowerstack[0]; + unsigned long ino = d_inode(lowerpath->dentry)->i_ino; + int fsid = lowerpath->layer->fsid; + struct ovl_inode_params oip = { + .upperdentry = upperdentry, + .lowerpath = lowerpath, + }; + + root = d_make_root(ovl_new_inode(sb, S_IFDIR, 0)); + if (!root) + return NULL; + + root->d_fsdata = oe; + + if (upperdentry) { + /* Root inode uses upper st_ino/i_ino */ + ino = d_inode(upperdentry)->i_ino; + fsid = 0; + ovl_dentry_set_upper_alias(root); + if (ovl_is_impuredir(sb, upperdentry)) + ovl_set_flag(OVL_IMPURE, d_inode(root)); + } + + /* Root is always merge -> can have whiteouts */ + ovl_set_flag(OVL_WHITEOUTS, d_inode(root)); + ovl_dentry_set_flag(OVL_E_CONNECTED, root); + ovl_set_upperdata(d_inode(root)); + ovl_inode_init(d_inode(root), &oip, ino, fsid); + ovl_dentry_update_reval(root, upperdentry, DCACHE_OP_WEAK_REVALIDATE); + + return root; +} + static int ovl_fill_super(struct super_block *sb, void *data, int silent) { struct path upperpath = { }; struct dentry *root_dentry; struct ovl_entry *oe; struct ovl_fs *ofs; + struct ovl_layer *layers; struct cred *cred; + char *splitlower = NULL; + unsigned int numlower; int err; + err = -EIO; + if (WARN_ON(sb->s_user_ns != current_user_ns())) + goto out; + + sb->s_d_op = &ovl_dentry_operations; + err = -ENOMEM; ofs = kzalloc(sizeof(struct ovl_fs), GFP_KERNEL); if (!ofs) goto out; + err = -ENOMEM; ofs->creator_cred = cred = prepare_creds(); if (!cred) goto out_err; + /* Is there a reason anyone would want not to share whiteouts? */ + ofs->share_whiteout = true; + ofs->config.index = ovl_index_def; + ofs->config.uuid = true; ofs->config.nfs_export = ovl_nfs_export_def; ofs->config.xino = ovl_xino_def(); ofs->config.metacopy = ovl_metacopy_def; @@ -1622,9 +2027,32 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent) goto out_err; } + err = -ENOMEM; + splitlower = kstrdup(ofs->config.lowerdir, GFP_KERNEL); + if (!splitlower) + goto out_err; + + err = -EINVAL; + numlower = ovl_split_lowerdirs(splitlower); + if (numlower > OVL_MAX_STACK) { + pr_err("too many lower directories, limit is %d\n", + OVL_MAX_STACK); + goto out_err; + } + + err = -ENOMEM; + layers = kcalloc(numlower + 1, sizeof(struct ovl_layer), GFP_KERNEL); + if (!layers) + goto out_err; + + ofs->layers = layers; + /* Layer 0 is reserved for upper even if there's no upper */ + ofs->numlayer = 1; + sb->s_stack_depth = 0; sb->s_maxbytes = MAX_LFS_FILESIZE; - /* Assume underlaying fs uses 32bit inodes unless proven otherwise */ + atomic_long_set(&ofs->last_ino, 1); + /* Assume underlying fs uses 32bit inodes unless proven otherwise */ if (ofs->config.xino != OVL_XINO_OFF) { ofs->xino_mode = BITS_PER_LONG - 32; if (!ofs->xino_mode) { @@ -1637,15 +2065,28 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent) sb->s_op = &ovl_super_operations; if (ofs->config.upperdir) { + struct super_block *upper_sb; + + err = -EINVAL; if (!ofs->config.workdir) { pr_err("missing 'workdir'\n"); goto out_err; } - err = ovl_get_upper(sb, ofs, &upperpath); + err = ovl_get_upper(sb, ofs, &layers[0], &upperpath); if (err) goto out_err; + upper_sb = ovl_upper_mnt(ofs)->mnt_sb; + if (!ovl_should_sync(ofs)) { + ofs->errseq = errseq_sample(&upper_sb->s_wb_err); + if (errseq_check(&upper_sb->s_wb_err, ofs->errseq)) { + err = -EIO; + pr_err("Cannot mount volatile when upperdir has an unseen error. Sync upperdir fs to clear state.\n"); + goto out_err; + } + } + err = ovl_get_workdir(sb, ofs, &upperpath); if (err) goto out_err; @@ -1653,31 +2094,31 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent) if (!ofs->workdir) sb->s_flags |= SB_RDONLY; - sb->s_stack_depth = ofs->upper_mnt->mnt_sb->s_stack_depth; - sb->s_time_gran = ofs->upper_mnt->mnt_sb->s_time_gran; - + sb->s_stack_depth = upper_sb->s_stack_depth; + sb->s_time_gran = upper_sb->s_time_gran; } - oe = ovl_get_lowerstack(sb, ofs); + oe = ovl_get_lowerstack(sb, splitlower, numlower, ofs, layers); err = PTR_ERR(oe); if (IS_ERR(oe)) goto out_err; /* If the upper fs is nonexistent, we mark overlayfs r/o too */ - if (!ofs->upper_mnt) + if (!ovl_upper_mnt(ofs)) sb->s_flags |= SB_RDONLY; - if (!(ovl_force_readonly(ofs)) && ofs->config.index) { + if (!ofs->config.uuid && ofs->numfs > 1) { + pr_warn("The uuid=off requires a single fs for lower and upper, falling back to uuid=on.\n"); + ofs->config.uuid = true; + } + + if (!ovl_force_readonly(ofs) && ofs->config.index) { err = ovl_get_indexdir(sb, ofs, oe, &upperpath); if (err) goto out_free_oe; /* Force r/o mount with no index dir */ - if (!ofs->indexdir) { - dput(ofs->workdir); - ofs->workdir = NULL; + if (!ofs->indexdir) sb->s_flags |= SB_RDONLY; - } - } err = ovl_check_overlapping_layers(sb, ofs); @@ -1687,7 +2128,7 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent) /* Show index=off in /proc/mounts for forced r/o mount */ if (!ofs->indexdir) { ofs->config.index = false; - if (ofs->upper_mnt && ofs->config.nfs_export) { + if (ovl_upper_mnt(ofs) && ofs->config.nfs_export) { pr_warn("NFS export requires an index dir, falling back to nfs_export=off.\n"); ofs->config.nfs_export = false; } @@ -1705,30 +2146,19 @@ static int ovl_fill_super(struct super_block *sb, void *data, int silent) cap_lower(cred->cap_effective, CAP_SYS_RESOURCE); sb->s_magic = OVERLAYFS_SUPER_MAGIC; - sb->s_xattr = ovl_xattr_handlers; + sb->s_xattr = ofs->config.userxattr ? ovl_user_xattr_handlers : + ovl_trusted_xattr_handlers; sb->s_fs_info = ofs; sb->s_flags |= SB_POSIXACL; + sb->s_iflags |= SB_I_SKIP_SYNC; err = -ENOMEM; - root_dentry = d_make_root(ovl_new_inode(sb, S_IFDIR, 0)); + root_dentry = ovl_get_root(sb, upperpath.dentry, oe); if (!root_dentry) goto out_free_oe; - root_dentry->d_fsdata = oe; - mntput(upperpath.mnt); - if (upperpath.dentry) { - ovl_dentry_set_upper_alias(root_dentry); - if (ovl_is_impuredir(upperpath.dentry)) - ovl_set_flag(OVL_IMPURE, d_inode(root_dentry)); - } - - /* Root is always merge -> can have whiteouts */ - ovl_set_flag(OVL_WHITEOUTS, d_inode(root_dentry)); - ovl_dentry_set_flag(OVL_E_CONNECTED, root_dentry); - ovl_set_upperdata(d_inode(root_dentry)); - ovl_inode_init(d_inode(root_dentry), upperpath.dentry, - ovl_dentry_lower(root_dentry), NULL); + kfree(splitlower); sb->s_root = root_dentry; @@ -1738,6 +2168,7 @@ out_free_oe: ovl_entry_stack_free(oe); kfree(oe); out_err: + kfree(splitlower); path_put(&upperpath); ovl_free_fs(ofs); out: @@ -1753,6 +2184,7 @@ static struct dentry *ovl_mount(struct file_system_type *fs_type, int flags, static struct file_system_type ovl_fs_type = { .owner = THIS_MODULE, .name = "overlay", + .fs_flags = FS_USERNS_MOUNT, .mount = ovl_mount, .kill_sb = kill_anon_super, }; |