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linux/fs/overlayfs/overlayfs.h
Linus Torvalds bb93c5ed45 vfs-6.8.rw 
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Merge tag 'vfs-6.8.rw' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

Pull vfs rw updates from Christian Brauner:
 "This contains updates from Amir for read-write backing file helpers
  for stacking filesystems such as overlayfs:

   - Fanotify is currently in the process of introducing pre content
     events. Roughly, a new permission event will be added indicating
     that it is safe to write to the file being accessed. These events
     are used by hierarchical storage managers to e.g., fill the content
     of files on first access.

     During that work we noticed that our current permission checking is
     inconsistent in rw_verify_area() and remap_verify_area().
     Especially in the splice code permission checking is done multiple
     times. For example, one time for the whole range and then again for
     partial ranges inside the iterator.

     In addition, we mostly do permission checking before we call
     file_start_write() except for a few places where we call it after.
     For pre-content events we need such permission checking to be done
     before file_start_write(). So this is a nice reason to clean this
     all up.

     After this series, all permission checking is done before
     file_start_write().

     As part of this cleanup we also massaged the splice code a bit. We
     got rid of a few helpers because we are alredy drowning in special
     read-write helpers. We also cleaned up the return types for splice
     helpers.

   - Introduce generic read-write helpers for backing files. This lifts
     some overlayfs code to common code so it can be used by the FUSE
     passthrough work coming in over the next cycles. Make Amir and
     Miklos the maintainers for this new subsystem of the vfs"

* tag 'vfs-6.8.rw' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (30 commits)
  fs: fix __sb_write_started() kerneldoc formatting
  fs: factor out backing_file_mmap() helper
  fs: factor out backing_file_splice_{read,write}() helpers
  fs: factor out backing_file_{read,write}_iter() helpers
  fs: prepare for stackable filesystems backing file helpers
  fsnotify: optionally pass access range in file permission hooks
  fsnotify: assert that file_start_write() is not held in permission hooks
  fsnotify: split fsnotify_perm() into two hooks
  fs: use splice_copy_file_range() inline helper
  splice: return type ssize_t from all helpers
  fs: use do_splice_direct() for nfsd/ksmbd server-side-copy
  fs: move file_start_write() into direct_splice_actor()
  fs: fork splice_file_range() from do_splice_direct()
  fs: create {sb,file}_write_not_started() helpers
  fs: create file_write_started() helper
  fs: create __sb_write_started() helper
  fs: move kiocb_start_write() into vfs_iocb_iter_write()
  fs: move permission hook out of do_iter_read()
  fs: move permission hook out of do_iter_write()
  fs: move file_start_write() into vfs_iter_write()
  ...
2024-01-08 11:11:51 -08:00

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/* 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 <linux/fsverity.h>
#include <linux/namei.h>
#include <linux/posix_acl.h>
#include <linux/posix_acl_xattr.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_NAMESPACE "overlay."
#define OVL_XATTR_TRUSTED_PREFIX XATTR_TRUSTED_PREFIX OVL_XATTR_NAMESPACE
#define OVL_XATTR_TRUSTED_PREFIX_LEN (sizeof(OVL_XATTR_TRUSTED_PREFIX) - 1)
#define OVL_XATTR_USER_PREFIX XATTR_USER_PREFIX OVL_XATTR_NAMESPACE
#define OVL_XATTR_USER_PREFIX_LEN (sizeof(OVL_XATTR_USER_PREFIX) - 1)
#define OVL_XATTR_ESCAPE_PREFIX OVL_XATTR_NAMESPACE
#define OVL_XATTR_ESCAPE_PREFIX_LEN (sizeof(OVL_XATTR_ESCAPE_PREFIX) - 1)
#define OVL_XATTR_ESCAPE_TRUSTED_PREFIX OVL_XATTR_TRUSTED_PREFIX OVL_XATTR_ESCAPE_PREFIX
#define OVL_XATTR_ESCAPE_TRUSTED_PREFIX_LEN (sizeof(OVL_XATTR_ESCAPE_TRUSTED_PREFIX) - 1)
#define OVL_XATTR_ESCAPE_USER_PREFIX OVL_XATTR_USER_PREFIX OVL_XATTR_ESCAPE_PREFIX
#define OVL_XATTR_ESCAPE_USER_PREFIX_LEN (sizeof(OVL_XATTR_ESCAPE_USER_PREFIX) - 1)
enum ovl_xattr {
OVL_XATTR_OPAQUE,
OVL_XATTR_REDIRECT,
OVL_XATTR_ORIGIN,
OVL_XATTR_IMPURE,
OVL_XATTR_NLINK,
OVL_XATTR_UPPER,
OVL_XATTR_UUID,
OVL_XATTR_METACOPY,
OVL_XATTR_PROTATTR,
OVL_XATTR_XWHITEOUT,
OVL_XATTR_XWHITEOUTS,
};
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,
OVL_HAS_DIGEST,
OVL_VERIFIED_DIGEST,
};
enum ovl_entry_flag {
OVL_E_UPPER_ALIAS,
OVL_E_OPAQUE,
OVL_E_CONNECTED,
};
enum {
OVL_REDIRECT_OFF, /* "off" mode is never used. In effect */
OVL_REDIRECT_FOLLOW, /* ...it translates to either "follow" */
OVL_REDIRECT_NOFOLLOW, /* ...or "nofollow". */
OVL_REDIRECT_ON,
};
enum {
OVL_UUID_OFF,
OVL_UUID_NULL,
OVL_UUID_AUTO,
OVL_UUID_ON,
};
enum {
OVL_XINO_OFF,
OVL_XINO_AUTO,
OVL_XINO_ON,
};
enum {
OVL_VERITY_OFF,
OVL_VERITY_ON,
OVL_VERITY_REQUIRE,
};
/*
* 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;
DECLARE_FLEX_ARRAY(u8, buf);
};
} __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))
/* On-disk format for "metacopy" xattr (if non-zero size) */
struct ovl_metacopy {
u8 version; /* 0 */
u8 len; /* size of this header + used digest bytes */
u8 flags;
u8 digest_algo; /* FS_VERITY_HASH_ALG_* constant, 0 for no digest */
u8 digest[FS_VERITY_MAX_DIGEST_SIZE]; /* Only the used part on disk */
} __packed;
#define OVL_METACOPY_MAX_SIZE (sizeof(struct ovl_metacopy))
#define OVL_METACOPY_MIN_SIZE (OVL_METACOPY_MAX_SIZE - FS_VERITY_MAX_DIGEST_SIZE)
#define OVL_METACOPY_INIT { 0, OVL_METACOPY_MIN_SIZE }
static inline int ovl_metadata_digest_size(const struct ovl_metacopy *metacopy)
{
if (metacopy->len < OVL_METACOPY_MIN_SIZE)
return 0;
return (int)metacopy->len - OVL_METACOPY_MIN_SIZE;
}
extern const char *const ovl_xattr_table[][2];
static inline const char *ovl_xattr(struct ovl_fs *ofs, enum ovl_xattr ox)
{
return ovl_xattr_table[ox][ofs->config.userxattr];
}
/*
* When changing ownership of an upper object map the intended ownership
* according to the upper layer's idmapping. When an upper mount idmaps files
* that are stored on-disk as owned by id 1001 to id 1000 this means stat on
* this object will report it as being owned by id 1000 when calling stat via
* the upper mount.
* In order to change ownership of an object so stat reports id 1000 when
* called on an idmapped upper mount the value written to disk - i.e., the
* value stored in ia_*id - must 1001. The mount mapping helper will thus take
* care to map 1000 to 1001.
* The mnt idmapping helpers are nops if the upper layer isn't idmapped.
*/
static inline int ovl_do_notify_change(struct ovl_fs *ofs,
struct dentry *upperdentry,
struct iattr *attr)
{
return notify_change(ovl_upper_mnt_idmap(ofs), upperdentry, attr, NULL);
}
static inline int ovl_do_rmdir(struct ovl_fs *ofs,
struct inode *dir, struct dentry *dentry)
{
int err = vfs_rmdir(ovl_upper_mnt_idmap(ofs), dir, dentry);
pr_debug("rmdir(%pd2) = %i\n", dentry, err);
return err;
}
static inline int ovl_do_unlink(struct ovl_fs *ofs, struct inode *dir,
struct dentry *dentry)
{
int err = vfs_unlink(ovl_upper_mnt_idmap(ofs), dir, dentry, NULL);
pr_debug("unlink(%pd2) = %i\n", dentry, err);
return err;
}
static inline int ovl_do_link(struct ovl_fs *ofs, struct dentry *old_dentry,
struct inode *dir, struct dentry *new_dentry)
{
int err = vfs_link(old_dentry, ovl_upper_mnt_idmap(ofs), 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 ovl_fs *ofs,
struct inode *dir, struct dentry *dentry,
umode_t mode)
{
int err = vfs_create(ovl_upper_mnt_idmap(ofs), dir, dentry, mode, true);
pr_debug("create(%pd2, 0%o) = %i\n", dentry, mode, err);
return err;
}
static inline int ovl_do_mkdir(struct ovl_fs *ofs,
struct inode *dir, struct dentry *dentry,
umode_t mode)
{
int err = vfs_mkdir(ovl_upper_mnt_idmap(ofs), dir, dentry, mode);
pr_debug("mkdir(%pd2, 0%o) = %i\n", dentry, mode, err);
return err;
}
static inline int ovl_do_mknod(struct ovl_fs *ofs,
struct inode *dir, struct dentry *dentry,
umode_t mode, dev_t dev)
{
int err = vfs_mknod(ovl_upper_mnt_idmap(ofs), 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 ovl_fs *ofs,
struct inode *dir, struct dentry *dentry,
const char *oldname)
{
int err = vfs_symlink(ovl_upper_mnt_idmap(ofs), dir, dentry, oldname);
pr_debug("symlink(\"%s\", %pd2) = %i\n", oldname, dentry, err);
return err;
}
static inline ssize_t ovl_do_getxattr(const struct path *path, const char *name,
void *value, size_t size)
{
int err, len;
WARN_ON(path->dentry->d_sb != path->mnt->mnt_sb);
err = vfs_getxattr(mnt_idmap(path->mnt), path->dentry,
name, value, size);
len = (value && err > 0) ? err : 0;
pr_debug("getxattr(%pd2, \"%s\", \"%*pE\", %zu, 0) = %i\n",
path->dentry, name, min(len, 48), value, size, err);
return err;
}
static inline ssize_t ovl_getxattr_upper(struct ovl_fs *ofs,
struct dentry *upperdentry,
enum ovl_xattr ox, void *value,
size_t size)
{
struct path upperpath = {
.dentry = upperdentry,
.mnt = ovl_upper_mnt(ofs),
};
return ovl_do_getxattr(&upperpath, ovl_xattr(ofs, ox), value, size);
}
static inline ssize_t ovl_path_getxattr(struct ovl_fs *ofs,
const struct path *path,
enum ovl_xattr ox, void *value,
size_t size)
{
return ovl_do_getxattr(path, ovl_xattr(ofs, ox), value, size);
}
static inline int ovl_do_setxattr(struct ovl_fs *ofs, struct dentry *dentry,
const char *name, const void *value,
size_t size, int flags)
{
int err = vfs_setxattr(ovl_upper_mnt_idmap(ofs), dentry, name,
value, size, flags);
pr_debug("setxattr(%pd2, \"%s\", \"%*pE\", %zu, %d) = %i\n",
dentry, name, min((int)size, 48), value, size, flags, err);
return err;
}
static inline int ovl_setxattr(struct ovl_fs *ofs, struct dentry *dentry,
enum ovl_xattr ox, const void *value,
size_t size)
{
return ovl_do_setxattr(ofs, dentry, ovl_xattr(ofs, ox), value, size, 0);
}
static inline int ovl_do_removexattr(struct ovl_fs *ofs, struct dentry *dentry,
const char *name)
{
int err = vfs_removexattr(ovl_upper_mnt_idmap(ofs), dentry, name);
pr_debug("removexattr(%pd2, \"%s\") = %i\n", dentry, name, err);
return err;
}
static inline int ovl_removexattr(struct ovl_fs *ofs, struct dentry *dentry,
enum ovl_xattr ox)
{
return ovl_do_removexattr(ofs, dentry, ovl_xattr(ofs, ox));
}
static inline int ovl_do_set_acl(struct ovl_fs *ofs, struct dentry *dentry,
const char *acl_name, struct posix_acl *acl)
{
return vfs_set_acl(ovl_upper_mnt_idmap(ofs), dentry, acl_name, acl);
}
static inline int ovl_do_remove_acl(struct ovl_fs *ofs, struct dentry *dentry,
const char *acl_name)
{
return vfs_remove_acl(ovl_upper_mnt_idmap(ofs), dentry, acl_name);
}
static inline int ovl_do_rename(struct ovl_fs *ofs, struct inode *olddir,
struct dentry *olddentry, struct inode *newdir,
struct dentry *newdentry, unsigned int flags)
{
int err;
struct renamedata rd = {
.old_mnt_idmap = ovl_upper_mnt_idmap(ofs),
.old_dir = olddir,
.old_dentry = olddentry,
.new_mnt_idmap = ovl_upper_mnt_idmap(ofs),
.new_dir = newdir,
.new_dentry = newdentry,
.flags = flags,
};
pr_debug("rename(%pd2, %pd2, 0x%x)\n", olddentry, newdentry, flags);
err = vfs_rename(&rd);
if (err) {
pr_debug("...rename(%pd2, %pd2, ...) = %i\n",
olddentry, newdentry, err);
}
return err;
}
static inline int ovl_do_whiteout(struct ovl_fs *ofs,
struct inode *dir, struct dentry *dentry)
{
int err = vfs_whiteout(ovl_upper_mnt_idmap(ofs), dir, dentry);
pr_debug("whiteout(%pd2) = %i\n", dentry, err);
return err;
}
static inline struct file *ovl_do_tmpfile(struct ovl_fs *ofs,
struct dentry *dentry, umode_t mode)
{
struct path path = { .mnt = ovl_upper_mnt(ofs), .dentry = dentry };
struct file *file = kernel_tmpfile_open(ovl_upper_mnt_idmap(ofs), &path,
mode, O_LARGEFILE | O_WRONLY,
current_cred());
int err = PTR_ERR_OR_ZERO(file);
pr_debug("tmpfile(%pd2, 0%o) = %i\n", dentry, mode, err);
return file;
}
static inline struct dentry *ovl_lookup_upper(struct ovl_fs *ofs,
const char *name,
struct dentry *base, int len)
{
return lookup_one(ovl_upper_mnt_idmap(ofs), name, base, len);
}
static inline bool ovl_open_flags_need_copy_up(int flags)
{
if (!flags)
return false;
return ((OPEN_FMODE(flags) & FMODE_WRITE) || (flags & O_TRUNC));
}
static inline int ovl_do_getattr(const struct path *path, struct kstat *stat,
u32 request_mask, unsigned int flags)
{
if (flags & AT_GETATTR_NOSEC)
return vfs_getattr_nosec(path, stat, request_mask, flags);
return vfs_getattr(path, stat, request_mask, flags);
}
/* util.c */
int ovl_get_write_access(struct dentry *dentry);
void ovl_put_write_access(struct dentry *dentry);
void ovl_start_write(struct dentry *dentry);
void ovl_end_write(struct dentry *dentry);
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);
static inline const struct cred *ovl_creds(struct super_block *sb)
{
return OVL_FS(sb)->creator_cred;
}
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_path *ovl_stack_alloc(unsigned int n);
void ovl_stack_cpy(struct ovl_path *dst, struct ovl_path *src, unsigned int n);
void ovl_stack_put(struct ovl_path *stack, unsigned int n);
void ovl_stack_free(struct ovl_path *stack, unsigned int n);
struct ovl_entry *ovl_alloc_entry(unsigned int numlower);
void ovl_free_entry(struct ovl_entry *oe);
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,
struct ovl_entry *oe);
void ovl_dentry_init_flags(struct dentry *dentry, struct dentry *upperdentry,
struct ovl_entry *oe, 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);
struct inode *ovl_i_path_real(struct inode *inode, struct path *path);
enum ovl_path_type ovl_path_real(struct dentry *dentry, struct path *path);
enum ovl_path_type ovl_path_realdata(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);
int ovl_dentry_set_lowerdata(struct dentry *dentry, struct ovl_path *datapath);
const struct ovl_layer *ovl_i_layer_lower(struct inode *inode);
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);
const char *ovl_lowerdata_redirect(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);
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_inode_version_get(struct inode *inode);
bool ovl_is_whiteout(struct dentry *dentry);
bool ovl_path_is_whiteout(struct ovl_fs *ofs, const struct path *path);
struct file *ovl_path_open(const 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_path_check_dir_xattr(struct ovl_fs *ofs, const struct path *path,
enum ovl_xattr ox);
bool ovl_path_check_origin_xattr(struct ovl_fs *ofs, const struct path *path);
bool ovl_path_check_xwhiteout_xattr(struct ovl_fs *ofs, const struct path *path);
bool ovl_path_check_xwhiteouts_xattr(struct ovl_fs *ofs, const struct path *path);
bool ovl_init_uuid_xattr(struct super_block *sb, struct ovl_fs *ofs,
const struct path *upperpath);
static inline bool ovl_upper_is_whiteout(struct ovl_fs *ofs,
struct dentry *upperdentry)
{
struct path upperpath = {
.dentry = upperdentry,
.mnt = ovl_upper_mnt(ofs),
};
return ovl_path_is_whiteout(ofs, &upperpath);
}
static inline bool ovl_check_origin_xattr(struct ovl_fs *ofs,
struct dentry *upperdentry)
{
struct path upperpath = {
.dentry = upperdentry,
.mnt = ovl_upper_mnt(ofs),
};
return ovl_path_check_origin_xattr(ofs, &upperpath);
}
int ovl_check_setxattr(struct ovl_fs *ofs, 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, const struct path *path,
struct ovl_metacopy *data);
int ovl_set_metacopy_xattr(struct ovl_fs *ofs, struct dentry *d,
struct ovl_metacopy *metacopy);
bool ovl_is_metacopy_dentry(struct dentry *dentry);
char *ovl_get_redirect_xattr(struct ovl_fs *ofs, const struct path *path, int padding);
int ovl_ensure_verity_loaded(struct path *path);
int ovl_get_verity_xattr(struct ovl_fs *ofs, const struct path *path,
u8 *digest_buf, int *buf_length);
int ovl_validate_verity(struct ovl_fs *ofs,
struct path *metapath,
struct path *datapath);
int ovl_get_verity_digest(struct ovl_fs *ofs, struct path *src,
struct ovl_metacopy *metacopy);
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 *upperdentry)
{
struct ovl_fs *ofs = OVL_FS(sb);
struct path upperpath = {
.dentry = upperdentry,
.mnt = ovl_upper_mnt(ofs),
};
return ovl_path_check_dir_xattr(ofs, &upperpath, OVL_XATTR_IMPURE);
}
static inline bool ovl_redirect_follow(struct ovl_fs *ofs)
{
return ofs->config.redirect_mode != OVL_REDIRECT_NOFOLLOW;
}
static inline bool ovl_redirect_dir(struct ovl_fs *ofs)
{
return ofs->config.redirect_mode == OVL_REDIRECT_ON;
}
static inline bool ovl_origin_uuid(struct ovl_fs *ofs)
{
return ofs->config.uuid != OVL_UUID_OFF;
}
static inline bool ovl_has_fsid(struct ovl_fs *ofs)
{
return ofs->config.uuid == OVL_UUID_ON ||
ofs->config.uuid == OVL_UUID_AUTO;
}
/*
* 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 ovl_fs *ofs)
{
return ofs->config.xino == OVL_XINO_ON;
}
/*
* To avoid regressions in existing setups with overlay lower offline changes,
* we allow lower changes only if none of the new features are used.
*/
static inline bool ovl_allow_offline_changes(struct ovl_fs *ofs)
{
return (!ofs->config.index && !ofs->config.metacopy &&
!ovl_redirect_dir(ofs) && !ovl_xino_warn(ofs));
}
/* All layers on same fs? */
static inline bool ovl_same_fs(struct ovl_fs *ofs)
{
return ofs->xino_mode == 0;
}
/* All overlay inodes have same st_dev? */
static inline bool ovl_same_dev(struct ovl_fs *ofs)
{
return ofs->xino_mode >= 0;
}
static inline unsigned int ovl_xino_bits(struct ovl_fs *ofs)
{
return ovl_same_dev(ofs) ? ofs->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_fs *ofs, 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, const struct ovl_fh *fh,
bool is_upper, bool set);
int ovl_verify_origin_xattr(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,
bool connected);
int ovl_verify_index(struct ovl_fs *ofs, struct dentry *index);
int ovl_get_index_name_fh(const struct ovl_fh *fh, struct qstr *name);
int ovl_get_index_name(struct ovl_fs *ofs, 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);
int ovl_verify_lowerdata(struct dentry *dentry);
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_fh(struct ovl_fs *ofs, struct dentry *upper,
const struct ovl_fh *fh, bool set)
{
return ovl_verify_set_fh(ofs, upper, OVL_XATTR_ORIGIN, fh, false, set);
}
static inline int ovl_verify_origin(struct ovl_fs *ofs, struct dentry *upper,
struct dentry *origin, bool set)
{
return ovl_verify_origin_xattr(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_origin_xattr(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 ovl_fs *ofs, 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(const struct path *realpath);
int ovl_workdir_cleanup(struct ovl_fs *ofs, 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 inode *dir)
{
return !ovl_test_flag(OVL_WHITEOUTS, 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_permission(struct mnt_idmap *idmap, struct inode *inode,
int mask);
#ifdef CONFIG_FS_POSIX_ACL
struct posix_acl *do_ovl_get_acl(struct mnt_idmap *idmap,
struct inode *inode, int type,
bool rcu, bool noperm);
static inline struct posix_acl *ovl_get_inode_acl(struct inode *inode, int type,
bool rcu)
{
return do_ovl_get_acl(&nop_mnt_idmap, inode, type, rcu, true);
}
static inline struct posix_acl *ovl_get_acl(struct mnt_idmap *idmap,
struct dentry *dentry, int type)
{
return do_ovl_get_acl(idmap, d_inode(dentry), type, false, false);
}
int ovl_set_acl(struct mnt_idmap *idmap, struct dentry *dentry,
struct posix_acl *acl, int type);
struct posix_acl *ovl_get_acl_path(const struct path *path,
const char *acl_name, bool noperm);
#else
#define ovl_get_inode_acl NULL
#define ovl_get_acl NULL
#define ovl_set_acl NULL
static inline struct posix_acl *ovl_get_acl_path(const struct path *path,
const char *acl_name,
bool noperm)
{
return NULL;
}
#endif
int ovl_update_time(struct inode *inode, 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_entry *oe;
bool index;
char *redirect;
char *lowerdata_redirect;
};
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);
void ovl_copyattr(struct inode *to);
/* vfs inode flags copied from real to ovl inode */
#define OVL_COPY_I_FLAGS_MASK (S_SYNC | S_NOATIME | S_APPEND | S_IMMUTABLE)
/* vfs inode flags read from overlay.protattr xattr to ovl inode */
#define OVL_PROT_I_FLAGS_MASK (S_APPEND | S_IMMUTABLE)
/*
* fileattr flags copied from lower to upper inode on copy up.
* We cannot copy up immutable/append-only flags, because that would prevent
* linking temp inode to upper dir, so we store them in xattr instead.
*/
#define OVL_COPY_FS_FLAGS_MASK (FS_SYNC_FL | FS_NOATIME_FL)
#define OVL_COPY_FSX_FLAGS_MASK (FS_XFLAG_SYNC | FS_XFLAG_NOATIME)
#define OVL_PROT_FS_FLAGS_MASK (FS_APPEND_FL | FS_IMMUTABLE_FL)
#define OVL_PROT_FSX_FLAGS_MASK (FS_XFLAG_APPEND | FS_XFLAG_IMMUTABLE)
void ovl_check_protattr(struct inode *inode, struct dentry *upper);
int ovl_set_protattr(struct inode *inode, struct dentry *upper,
struct fileattr *fa);
static inline void ovl_copyflags(struct inode *from, struct inode *to)
{
unsigned int mask = OVL_COPY_I_FLAGS_MASK;
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 ovl_fs *ofs, struct inode *dir,
struct dentry **newdentry, umode_t mode);
struct dentry *ovl_create_real(struct ovl_fs *ofs,
struct inode *dir, struct dentry *newdentry,
struct ovl_cattr *attr);
int ovl_cleanup(struct ovl_fs *ofs, struct inode *dir, struct dentry *dentry);
struct dentry *ovl_lookup_temp(struct ovl_fs *ofs, struct dentry *workdir);
struct dentry *ovl_create_temp(struct ovl_fs *ofs, struct dentry *workdir,
struct ovl_cattr *attr);
/* file.c */
extern const struct file_operations ovl_file_operations;
int ovl_real_fileattr_get(const struct path *realpath, struct fileattr *fa);
int ovl_real_fileattr_set(const struct path *realpath, struct fileattr *fa);
int ovl_fileattr_get(struct dentry *dentry, struct fileattr *fa);
int ovl_fileattr_set(struct mnt_idmap *idmap,
struct dentry *dentry, struct fileattr *fa);
/* 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, const struct path *path, struct dentry *new);
int ovl_set_attr(struct ovl_fs *ofs, struct dentry *upper, struct kstat *stat);
struct ovl_fh *ovl_encode_real_fh(struct ovl_fs *ofs, struct dentry *real,
bool is_upper);
struct ovl_fh *ovl_get_origin_fh(struct ovl_fs *ofs, struct dentry *origin);
int ovl_set_origin_fh(struct ovl_fs *ofs, const struct ovl_fh *fh,
struct dentry *upper);
/* export.c */
extern const struct export_operations ovl_export_operations;
extern const struct export_operations ovl_export_fid_operations;
/* super.c */
int ovl_fill_super(struct super_block *sb, struct fs_context *fc);
/* Will this overlay be forced to mount/remount ro? */
static inline bool ovl_force_readonly(struct ovl_fs *ofs)
{
return (!ovl_upper_mnt(ofs) || !ofs->workdir);
}
/* xattr.c */
const struct xattr_handler * const *ovl_xattr_handlers(struct ovl_fs *ofs);
int ovl_setattr(struct mnt_idmap *idmap, struct dentry *dentry,
struct iattr *attr);
int ovl_getattr(struct mnt_idmap *idmap, const struct path *path,
struct kstat *stat, u32 request_mask, unsigned int flags);
ssize_t ovl_listxattr(struct dentry *dentry, char *list, size_t size);
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