diff options
Diffstat (limited to 'fs/overlayfs/overlayfs.h')
| -rw-r--r-- | fs/overlayfs/overlayfs.h | 550 |
1 files changed, 550 insertions, 0 deletions
diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h new file mode 100644 index 000000000..26f91868f --- /dev/null +++ b/fs/overlayfs/overlayfs.h @@ -0,0 +1,550 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * + * Copyright (C) 2011 Novell Inc. + */ + +#include <linux/kernel.h> +#include <linux/uuid.h> +#include <linux/fs.h> +#include "ovl_entry.h" + +#undef pr_fmt +#define pr_fmt(fmt) "overlayfs: " fmt + +enum ovl_path_type { + __OVL_PATH_UPPER = (1 << 0), + __OVL_PATH_MERGE = (1 << 1), + __OVL_PATH_ORIGIN = (1 << 2), +}; + +#define OVL_TYPE_UPPER(type) ((type) & __OVL_PATH_UPPER) +#define OVL_TYPE_MERGE(type) ((type) & __OVL_PATH_MERGE) +#define OVL_TYPE_ORIGIN(type) ((type) & __OVL_PATH_ORIGIN) + +#define OVL_XATTR_PREFIX XATTR_TRUSTED_PREFIX "overlay." + +enum ovl_xattr { + OVL_XATTR_OPAQUE, + OVL_XATTR_REDIRECT, + OVL_XATTR_ORIGIN, + OVL_XATTR_IMPURE, + OVL_XATTR_NLINK, + OVL_XATTR_UPPER, + OVL_XATTR_METACOPY, +}; + +enum ovl_inode_flag { + /* Pure upper dir that may contain non pure upper entries */ + OVL_IMPURE, + /* Non-merge dir that may contain whiteout entries */ + OVL_WHITEOUTS, + OVL_INDEX, + OVL_UPPERDATA, + /* Inode number will remain constant over copy up. */ + OVL_CONST_INO, +}; + +enum ovl_entry_flag { + OVL_E_UPPER_ALIAS, + OVL_E_OPAQUE, + OVL_E_CONNECTED, +}; + +enum { + OVL_XINO_OFF, + OVL_XINO_AUTO, + OVL_XINO_ON, +}; + +/* + * The tuple (fh,uuid) is a universal unique identifier for a copy up origin, + * where: + * origin.fh - exported file handle of the lower file + * origin.uuid - uuid of the lower filesystem + */ +#define OVL_FH_VERSION 0 +#define OVL_FH_MAGIC 0xfb + +/* CPU byte order required for fid decoding: */ +#define OVL_FH_FLAG_BIG_ENDIAN (1 << 0) +#define OVL_FH_FLAG_ANY_ENDIAN (1 << 1) +/* Is the real inode encoded in fid an upper inode? */ +#define OVL_FH_FLAG_PATH_UPPER (1 << 2) + +#define OVL_FH_FLAG_ALL (OVL_FH_FLAG_BIG_ENDIAN | OVL_FH_FLAG_ANY_ENDIAN | \ + OVL_FH_FLAG_PATH_UPPER) + +#if defined(__LITTLE_ENDIAN) +#define OVL_FH_FLAG_CPU_ENDIAN 0 +#elif defined(__BIG_ENDIAN) +#define OVL_FH_FLAG_CPU_ENDIAN OVL_FH_FLAG_BIG_ENDIAN +#else +#error Endianness not defined +#endif + +/* The type used to be returned by overlay exportfs for misaligned fid */ +#define OVL_FILEID_V0 0xfb +/* The type returned by overlay exportfs for 32bit aligned fid */ +#define OVL_FILEID_V1 0xf8 + +/* On-disk format for "origin" file handle */ +struct ovl_fb { + u8 version; /* 0 */ + u8 magic; /* 0xfb */ + u8 len; /* size of this header + size of fid */ + u8 flags; /* OVL_FH_FLAG_* */ + u8 type; /* fid_type of fid */ + uuid_t uuid; /* uuid of filesystem */ + u32 fid[]; /* file identifier should be 32bit aligned in-memory */ +} __packed; + +/* In-memory and on-wire format for overlay file handle */ +struct ovl_fh { + u8 padding[3]; /* make sure fb.fid is 32bit aligned */ + union { + struct ovl_fb fb; + u8 buf[0]; + }; +} __packed; + +#define OVL_FH_WIRE_OFFSET offsetof(struct ovl_fh, fb) +#define OVL_FH_LEN(fh) (OVL_FH_WIRE_OFFSET + (fh)->fb.len) +#define OVL_FH_FID_OFFSET (OVL_FH_WIRE_OFFSET + \ + offsetof(struct ovl_fb, fid)) + +extern const char *ovl_xattr_table[]; +static inline const char *ovl_xattr(struct ovl_fs *ofs, enum ovl_xattr ox) +{ + return ovl_xattr_table[ox]; +} + +static inline int ovl_do_rmdir(struct inode *dir, struct dentry *dentry) +{ + int err = vfs_rmdir(dir, dentry); + + pr_debug("rmdir(%pd2) = %i\n", dentry, err); + return err; +} + +static inline int ovl_do_unlink(struct inode *dir, struct dentry *dentry) +{ + int err = vfs_unlink(dir, dentry, NULL); + + pr_debug("unlink(%pd2) = %i\n", dentry, err); + return err; +} + +static inline int ovl_do_link(struct dentry *old_dentry, struct inode *dir, + struct dentry *new_dentry) +{ + int err = vfs_link(old_dentry, dir, new_dentry, NULL); + + pr_debug("link(%pd2, %pd2) = %i\n", old_dentry, new_dentry, err); + return err; +} + +static inline int ovl_do_create(struct inode *dir, struct dentry *dentry, + umode_t mode) +{ + int err = vfs_create(dir, dentry, mode, true); + + pr_debug("create(%pd2, 0%o) = %i\n", dentry, mode, err); + return err; +} + +static inline int ovl_do_mkdir(struct inode *dir, struct dentry *dentry, + umode_t mode) +{ + int err = vfs_mkdir(dir, dentry, mode); + pr_debug("mkdir(%pd2, 0%o) = %i\n", dentry, mode, err); + return err; +} + +static inline int ovl_do_mknod(struct inode *dir, struct dentry *dentry, + umode_t mode, dev_t dev) +{ + int err = vfs_mknod(dir, dentry, mode, dev); + + pr_debug("mknod(%pd2, 0%o, 0%o) = %i\n", dentry, mode, dev, err); + return err; +} + +static inline int ovl_do_symlink(struct inode *dir, struct dentry *dentry, + const char *oldname) +{ + int err = vfs_symlink(dir, dentry, oldname); + + pr_debug("symlink(\"%s\", %pd2) = %i\n", oldname, dentry, err); + return err; +} + +static inline ssize_t ovl_do_getxattr(struct ovl_fs *ofs, struct dentry *dentry, + enum ovl_xattr ox, void *value, + size_t size) +{ + const char *name = ovl_xattr(ofs, ox); + return vfs_getxattr(dentry, name, value, size); +} + +static inline int ovl_do_setxattr(struct ovl_fs *ofs, struct dentry *dentry, + enum ovl_xattr ox, const void *value, + size_t size) +{ + const char *name = ovl_xattr(ofs, ox); + int err = vfs_setxattr(dentry, name, value, size, 0); + pr_debug("setxattr(%pd2, \"%s\", \"%*pE\", %zu, 0) = %i\n", + dentry, name, min((int)size, 48), value, size, err); + return err; +} + +static inline int ovl_do_removexattr(struct ovl_fs *ofs, struct dentry *dentry, + enum ovl_xattr ox) +{ + const char *name = ovl_xattr(ofs, ox); + int err = vfs_removexattr(dentry, name); + pr_debug("removexattr(%pd2, \"%s\") = %i\n", dentry, name, err); + return err; +} + +static inline int ovl_do_rename(struct inode *olddir, struct dentry *olddentry, + struct inode *newdir, struct dentry *newdentry, + unsigned int flags) +{ + int err; + + pr_debug("rename(%pd2, %pd2, 0x%x)\n", olddentry, newdentry, flags); + err = vfs_rename(olddir, olddentry, newdir, newdentry, NULL, flags); + if (err) { + pr_debug("...rename(%pd2, %pd2, ...) = %i\n", + olddentry, newdentry, err); + } + return err; +} + +static inline int ovl_do_whiteout(struct inode *dir, struct dentry *dentry) +{ + int err = vfs_whiteout(dir, dentry); + pr_debug("whiteout(%pd2) = %i\n", dentry, err); + return err; +} + +static inline struct dentry *ovl_do_tmpfile(struct dentry *dentry, umode_t mode) +{ + struct dentry *ret = vfs_tmpfile(dentry, mode, 0); + int err = PTR_ERR_OR_ZERO(ret); + + pr_debug("tmpfile(%pd2, 0%o) = %i\n", dentry, mode, err); + return ret; +} + +static inline bool ovl_open_flags_need_copy_up(int flags) +{ + if (!flags) + return false; + + return ((OPEN_FMODE(flags) & FMODE_WRITE) || (flags & O_TRUNC)); +} + +/* util.c */ +int ovl_want_write(struct dentry *dentry); +void ovl_drop_write(struct dentry *dentry); +struct dentry *ovl_workdir(struct dentry *dentry); +const struct cred *ovl_override_creds(struct super_block *sb); +int ovl_can_decode_fh(struct super_block *sb); +struct dentry *ovl_indexdir(struct super_block *sb); +bool ovl_index_all(struct super_block *sb); +bool ovl_verify_lower(struct super_block *sb); +struct ovl_entry *ovl_alloc_entry(unsigned int numlower); +bool ovl_dentry_remote(struct dentry *dentry); +void ovl_dentry_update_reval(struct dentry *dentry, struct dentry *realdentry); +void ovl_dentry_init_reval(struct dentry *dentry, struct dentry *upperdentry); +void ovl_dentry_init_flags(struct dentry *dentry, struct dentry *upperdentry, + unsigned int mask); +bool ovl_dentry_weird(struct dentry *dentry); +enum ovl_path_type ovl_path_type(struct dentry *dentry); +void ovl_path_upper(struct dentry *dentry, struct path *path); +void ovl_path_lower(struct dentry *dentry, struct path *path); +void ovl_path_lowerdata(struct dentry *dentry, struct path *path); +enum ovl_path_type ovl_path_real(struct dentry *dentry, struct path *path); +struct dentry *ovl_dentry_upper(struct dentry *dentry); +struct dentry *ovl_dentry_lower(struct dentry *dentry); +struct dentry *ovl_dentry_lowerdata(struct dentry *dentry); +const struct ovl_layer *ovl_layer_lower(struct dentry *dentry); +struct dentry *ovl_dentry_real(struct dentry *dentry); +struct dentry *ovl_i_dentry_upper(struct inode *inode); +struct inode *ovl_inode_upper(struct inode *inode); +struct inode *ovl_inode_lower(struct inode *inode); +struct inode *ovl_inode_lowerdata(struct inode *inode); +struct inode *ovl_inode_real(struct inode *inode); +struct inode *ovl_inode_realdata(struct inode *inode); +struct ovl_dir_cache *ovl_dir_cache(struct inode *inode); +void ovl_set_dir_cache(struct inode *inode, struct ovl_dir_cache *cache); +void ovl_dentry_set_flag(unsigned long flag, struct dentry *dentry); +void ovl_dentry_clear_flag(unsigned long flag, struct dentry *dentry); +bool ovl_dentry_test_flag(unsigned long flag, struct dentry *dentry); +bool ovl_dentry_is_opaque(struct dentry *dentry); +bool ovl_dentry_is_whiteout(struct dentry *dentry); +void ovl_dentry_set_opaque(struct dentry *dentry); +bool ovl_dentry_has_upper_alias(struct dentry *dentry); +void ovl_dentry_set_upper_alias(struct dentry *dentry); +bool ovl_dentry_needs_data_copy_up(struct dentry *dentry, int flags); +bool ovl_dentry_needs_data_copy_up_locked(struct dentry *dentry, int flags); +bool ovl_has_upperdata(struct inode *inode); +void ovl_set_upperdata(struct inode *inode); +bool ovl_redirect_dir(struct super_block *sb); +const char *ovl_dentry_get_redirect(struct dentry *dentry); +void ovl_dentry_set_redirect(struct dentry *dentry, const char *redirect); +void ovl_inode_update(struct inode *inode, struct dentry *upperdentry); +void ovl_dir_modified(struct dentry *dentry, bool impurity); +u64 ovl_dentry_version_get(struct dentry *dentry); +bool ovl_is_whiteout(struct dentry *dentry); +struct file *ovl_path_open(struct path *path, int flags); +int ovl_copy_up_start(struct dentry *dentry, int flags); +void ovl_copy_up_end(struct dentry *dentry); +bool ovl_already_copied_up(struct dentry *dentry, int flags); +bool ovl_check_origin_xattr(struct ovl_fs *ofs, struct dentry *dentry); +bool ovl_check_dir_xattr(struct super_block *sb, struct dentry *dentry, + enum ovl_xattr ox); +int ovl_check_setxattr(struct dentry *dentry, struct dentry *upperdentry, + enum ovl_xattr ox, const void *value, size_t size, + int xerr); +int ovl_set_impure(struct dentry *dentry, struct dentry *upperdentry); +bool ovl_inuse_trylock(struct dentry *dentry); +void ovl_inuse_unlock(struct dentry *dentry); +bool ovl_is_inuse(struct dentry *dentry); +bool ovl_need_index(struct dentry *dentry); +int ovl_nlink_start(struct dentry *dentry); +void ovl_nlink_end(struct dentry *dentry); +int ovl_lock_rename_workdir(struct dentry *workdir, struct dentry *upperdir); +int ovl_check_metacopy_xattr(struct ovl_fs *ofs, struct dentry *dentry); +bool ovl_is_metacopy_dentry(struct dentry *dentry); +char *ovl_get_redirect_xattr(struct ovl_fs *ofs, struct dentry *dentry, + int padding); +int ovl_sync_status(struct ovl_fs *ofs); + +static inline void ovl_set_flag(unsigned long flag, struct inode *inode) +{ + set_bit(flag, &OVL_I(inode)->flags); +} + +static inline void ovl_clear_flag(unsigned long flag, struct inode *inode) +{ + clear_bit(flag, &OVL_I(inode)->flags); +} + +static inline bool ovl_test_flag(unsigned long flag, struct inode *inode) +{ + return test_bit(flag, &OVL_I(inode)->flags); +} + +static inline bool ovl_is_impuredir(struct super_block *sb, + struct dentry *dentry) +{ + return ovl_check_dir_xattr(sb, dentry, OVL_XATTR_IMPURE); +} + +/* + * With xino=auto, we do best effort to keep all inodes on same st_dev and + * d_ino consistent with st_ino. + * With xino=on, we do the same effort but we warn if we failed. + */ +static inline bool ovl_xino_warn(struct super_block *sb) +{ + return OVL_FS(sb)->config.xino == OVL_XINO_ON; +} + +/* All layers on same fs? */ +static inline bool ovl_same_fs(struct super_block *sb) +{ + return OVL_FS(sb)->xino_mode == 0; +} + +/* All overlay inodes have same st_dev? */ +static inline bool ovl_same_dev(struct super_block *sb) +{ + return OVL_FS(sb)->xino_mode >= 0; +} + +static inline unsigned int ovl_xino_bits(struct super_block *sb) +{ + return ovl_same_dev(sb) ? OVL_FS(sb)->xino_mode : 0; +} + +static inline void ovl_inode_lock(struct inode *inode) +{ + mutex_lock(&OVL_I(inode)->lock); +} + +static inline int ovl_inode_lock_interruptible(struct inode *inode) +{ + return mutex_lock_interruptible(&OVL_I(inode)->lock); +} + +static inline void ovl_inode_unlock(struct inode *inode) +{ + mutex_unlock(&OVL_I(inode)->lock); +} + + +/* namei.c */ +int ovl_check_fb_len(struct ovl_fb *fb, int fb_len); + +static inline int ovl_check_fh_len(struct ovl_fh *fh, int fh_len) +{ + if (fh_len < sizeof(struct ovl_fh)) + return -EINVAL; + + return ovl_check_fb_len(&fh->fb, fh_len - OVL_FH_WIRE_OFFSET); +} + +struct dentry *ovl_decode_real_fh(struct ovl_fh *fh, struct vfsmount *mnt, + bool connected); +int ovl_check_origin_fh(struct ovl_fs *ofs, struct ovl_fh *fh, bool connected, + struct dentry *upperdentry, struct ovl_path **stackp); +int ovl_verify_set_fh(struct ovl_fs *ofs, struct dentry *dentry, + enum ovl_xattr ox, struct dentry *real, bool is_upper, + bool set); +struct dentry *ovl_index_upper(struct ovl_fs *ofs, struct dentry *index); +int ovl_verify_index(struct ovl_fs *ofs, struct dentry *index); +int ovl_get_index_name(struct dentry *origin, struct qstr *name); +struct dentry *ovl_get_index_fh(struct ovl_fs *ofs, struct ovl_fh *fh); +struct dentry *ovl_lookup_index(struct ovl_fs *ofs, struct dentry *upper, + struct dentry *origin, bool verify); +int ovl_path_next(int idx, struct dentry *dentry, struct path *path); +struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry, + unsigned int flags); +bool ovl_lower_positive(struct dentry *dentry); + +static inline int ovl_verify_origin(struct ovl_fs *ofs, struct dentry *upper, + struct dentry *origin, bool set) +{ + return ovl_verify_set_fh(ofs, upper, OVL_XATTR_ORIGIN, origin, + false, set); +} + +static inline int ovl_verify_upper(struct ovl_fs *ofs, struct dentry *index, + struct dentry *upper, bool set) +{ + return ovl_verify_set_fh(ofs, index, OVL_XATTR_UPPER, upper, true, set); +} + +/* readdir.c */ +extern const struct file_operations ovl_dir_operations; +struct file *ovl_dir_real_file(const struct file *file, bool want_upper); +int ovl_check_empty_dir(struct dentry *dentry, struct list_head *list); +void ovl_cleanup_whiteouts(struct dentry *upper, struct list_head *list); +void ovl_cache_free(struct list_head *list); +void ovl_dir_cache_free(struct inode *inode); +int ovl_check_d_type_supported(struct path *realpath); +int ovl_workdir_cleanup(struct inode *dir, struct vfsmount *mnt, + struct dentry *dentry, int level); +int ovl_indexdir_cleanup(struct ovl_fs *ofs); + +/* + * 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 inline bool ovl_dir_is_real(struct dentry *dir) +{ + return !ovl_test_flag(OVL_WHITEOUTS, d_inode(dir)); +} + +/* inode.c */ +int ovl_set_nlink_upper(struct dentry *dentry); +int ovl_set_nlink_lower(struct dentry *dentry); +unsigned int ovl_get_nlink(struct ovl_fs *ofs, struct dentry *lowerdentry, + struct dentry *upperdentry, + unsigned int fallback); +int ovl_setattr(struct dentry *dentry, struct iattr *attr); +int ovl_getattr(const struct path *path, struct kstat *stat, + u32 request_mask, unsigned int flags); +int ovl_permission(struct inode *inode, int mask); +int ovl_xattr_set(struct dentry *dentry, struct inode *inode, const char *name, + const void *value, size_t size, int flags); +int ovl_xattr_get(struct dentry *dentry, struct inode *inode, const char *name, + void *value, size_t size); +ssize_t ovl_listxattr(struct dentry *dentry, char *list, size_t size); +struct posix_acl *ovl_get_acl(struct inode *inode, int type); +int ovl_update_time(struct inode *inode, struct timespec64 *ts, int flags); +bool ovl_is_private_xattr(struct super_block *sb, const char *name); + +struct ovl_inode_params { + struct inode *newinode; + struct dentry *upperdentry; + struct ovl_path *lowerpath; + bool index; + unsigned int numlower; + char *redirect; + struct dentry *lowerdata; +}; +void ovl_inode_init(struct inode *inode, struct ovl_inode_params *oip, + unsigned long ino, int fsid); +struct inode *ovl_new_inode(struct super_block *sb, umode_t mode, dev_t rdev); +struct inode *ovl_lookup_inode(struct super_block *sb, struct dentry *real, + bool is_upper); +bool ovl_lookup_trap_inode(struct super_block *sb, struct dentry *dir); +struct inode *ovl_get_trap_inode(struct super_block *sb, struct dentry *dir); +struct inode *ovl_get_inode(struct super_block *sb, + struct ovl_inode_params *oip); +static inline void ovl_copyattr(struct inode *from, struct inode *to) +{ + to->i_uid = from->i_uid; + to->i_gid = from->i_gid; + to->i_mode = from->i_mode; + to->i_atime = from->i_atime; + to->i_mtime = from->i_mtime; + to->i_ctime = from->i_ctime; + i_size_write(to, i_size_read(from)); +} + +static inline void ovl_copyflags(struct inode *from, struct inode *to) +{ + unsigned int mask = S_SYNC | S_IMMUTABLE | S_APPEND | S_NOATIME; + + inode_set_flags(to, from->i_flags & mask, mask); +} + +/* dir.c */ +extern const struct inode_operations ovl_dir_inode_operations; +int ovl_cleanup_and_whiteout(struct ovl_fs *ofs, struct inode *dir, + struct dentry *dentry); +struct ovl_cattr { + dev_t rdev; + umode_t mode; + const char *link; + struct dentry *hardlink; +}; + +#define OVL_CATTR(m) (&(struct ovl_cattr) { .mode = (m) }) + +int ovl_mkdir_real(struct inode *dir, struct dentry **newdentry, umode_t mode); +struct dentry *ovl_create_real(struct inode *dir, struct dentry *newdentry, + struct ovl_cattr *attr); +int ovl_cleanup(struct inode *dir, struct dentry *dentry); +struct dentry *ovl_lookup_temp(struct dentry *workdir); +struct dentry *ovl_create_temp(struct dentry *workdir, struct ovl_cattr *attr); + +/* file.c */ +extern const struct file_operations ovl_file_operations; +int __init ovl_aio_request_cache_init(void); +void ovl_aio_request_cache_destroy(void); +long ovl_ioctl(struct file *file, unsigned int cmd, unsigned long arg); +long ovl_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg); + +/* copy_up.c */ +int ovl_copy_up(struct dentry *dentry); +int ovl_copy_up_with_data(struct dentry *dentry); +int ovl_maybe_copy_up(struct dentry *dentry, int flags); +int ovl_copy_xattr(struct super_block *sb, struct dentry *old, + struct dentry *new); +int ovl_set_attr(struct dentry *upper, struct kstat *stat); +struct ovl_fh *ovl_encode_real_fh(struct dentry *real, bool is_upper); +int ovl_set_origin(struct dentry *dentry, struct dentry *lower, + struct dentry *upper); + +/* export.c */ +extern const struct export_operations ovl_export_operations; |