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linux-next/include/linux/fuse.h
John Muir 451d0f5999 FUSE: Notifying the kernel of deletion. 
Allows a FUSE file-system to tell the kernel when a file or directory is
deleted. If the specified dentry has the specified inode number, the kernel will
unhash it.

The current 'fuse_notify_inval_entry' does not cause the kernel to clean up
directories that are in use properly, and as a result the users of those
directories see incorrect semantics from the file-system. The error condition
seen when 'fuse_notify_inval_entry' is used to notify of a deleted directory is
avoided when 'fuse_notify_delete' is used instead.

The following scenario demonstrates the difference:
1. User A chdirs into 'testdir' and starts reading 'testfile'.
2. User B rm -rf 'testdir'.
3. User B creates 'testdir'.
4. User C chdirs into 'testdir'.

If you run the above within the same machine on any file-system (including fuse
file-systems), there is no problem: user C is able to chdir into the new
testdir. The old testdir is removed from the dentry tree, but still open by user
A.

If operations 2 and 3 are performed via the network such that the fuse
file-system uses one of the notify functions to tell the kernel that the nodes
are gone, then the following error occurs for user C while user A holds the
original directory open:

muirj@empacher:~> ls /test/testdir
ls: cannot access /test/testdir: No such file or directory

The issue here is that the kernel still has a dentry for testdir, and so it is
requesting the attributes for the old directory, while the file-system is
responding that the directory no longer exists.

If on the other hand, if the file-system can notify the kernel that the
directory is deleted using the new 'fuse_notify_delete' function, then the above
ls will find the new directory as expected.

Signed-off-by: John Muir <john@jmuir.com>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
2011-12-13 11:58:49 +01:00

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/*
FUSE: Filesystem in Userspace
Copyright (C) 2001-2008 Miklos Szeredi <miklos@szeredi.hu>
This program can be distributed under the terms of the GNU GPL.
See the file COPYING.
*/
/*
* This file defines the kernel interface of FUSE
*
* Protocol changelog:
*
* 7.9:
* - new fuse_getattr_in input argument of GETATTR
* - add lk_flags in fuse_lk_in
* - add lock_owner field to fuse_setattr_in, fuse_read_in and fuse_write_in
* - add blksize field to fuse_attr
* - add file flags field to fuse_read_in and fuse_write_in
*
* 7.10
* - add nonseekable open flag
*
* 7.11
* - add IOCTL message
* - add unsolicited notification support
* - add POLL message and NOTIFY_POLL notification
*
* 7.12
* - add umask flag to input argument of open, mknod and mkdir
* - add notification messages for invalidation of inodes and
* directory entries
*
* 7.13
* - make max number of background requests and congestion threshold
* tunables
*
* 7.14
* - add splice support to fuse device
*
* 7.15
* - add store notify
* - add retrieve notify
*
* 7.16
* - add BATCH_FORGET request
* - FUSE_IOCTL_UNRESTRICTED shall now return with array of 'struct
* fuse_ioctl_iovec' instead of ambiguous 'struct iovec'
* - add FUSE_IOCTL_32BIT flag
*
* 7.17
* - add FUSE_FLOCK_LOCKS and FUSE_RELEASE_FLOCK_UNLOCK
*
* 7.18
* - add FUSE_IOCTL_DIR flag
* - add FUSE_NOTIFY_DELETE
*/
#ifndef _LINUX_FUSE_H
#define _LINUX_FUSE_H
#include <linux/types.h>
/*
* Version negotiation:
*
* Both the kernel and userspace send the version they support in the
* INIT request and reply respectively.
*
* If the major versions match then both shall use the smallest
* of the two minor versions for communication.
*
* If the kernel supports a larger major version, then userspace shall
* reply with the major version it supports, ignore the rest of the
* INIT message and expect a new INIT message from the kernel with a
* matching major version.
*
* If the library supports a larger major version, then it shall fall
* back to the major protocol version sent by the kernel for
* communication and reply with that major version (and an arbitrary
* supported minor version).
*/
/** Version number of this interface */
#define FUSE_KERNEL_VERSION 7
/** Minor version number of this interface */
#define FUSE_KERNEL_MINOR_VERSION 18
/** The node ID of the root inode */
#define FUSE_ROOT_ID 1
/* Make sure all structures are padded to 64bit boundary, so 32bit
userspace works under 64bit kernels */
struct fuse_attr {
__u64 ino;
__u64 size;
__u64 blocks;
__u64 atime;
__u64 mtime;
__u64 ctime;
__u32 atimensec;
__u32 mtimensec;
__u32 ctimensec;
__u32 mode;
__u32 nlink;
__u32 uid;
__u32 gid;
__u32 rdev;
__u32 blksize;
__u32 padding;
};
struct fuse_kstatfs {
__u64 blocks;
__u64 bfree;
__u64 bavail;
__u64 files;
__u64 ffree;
__u32 bsize;
__u32 namelen;
__u32 frsize;
__u32 padding;
__u32 spare[6];
};
struct fuse_file_lock {
__u64 start;
__u64 end;
__u32 type;
__u32 pid; /* tgid */
};
/**
* Bitmasks for fuse_setattr_in.valid
*/
#define FATTR_MODE (1 << 0)
#define FATTR_UID (1 << 1)
#define FATTR_GID (1 << 2)
#define FATTR_SIZE (1 << 3)
#define FATTR_ATIME (1 << 4)
#define FATTR_MTIME (1 << 5)
#define FATTR_FH (1 << 6)
#define FATTR_ATIME_NOW (1 << 7)
#define FATTR_MTIME_NOW (1 << 8)
#define FATTR_LOCKOWNER (1 << 9)
/**
* Flags returned by the OPEN request
*
* FOPEN_DIRECT_IO: bypass page cache for this open file
* FOPEN_KEEP_CACHE: don't invalidate the data cache on open
* FOPEN_NONSEEKABLE: the file is not seekable
*/
#define FOPEN_DIRECT_IO (1 << 0)
#define FOPEN_KEEP_CACHE (1 << 1)
#define FOPEN_NONSEEKABLE (1 << 2)
/**
* INIT request/reply flags
*
* FUSE_POSIX_LOCKS: remote locking for POSIX file locks
* FUSE_EXPORT_SUPPORT: filesystem handles lookups of "." and ".."
* FUSE_DONT_MASK: don't apply umask to file mode on create operations
* FUSE_FLOCK_LOCKS: remote locking for BSD style file locks
*/
#define FUSE_ASYNC_READ (1 << 0)
#define FUSE_POSIX_LOCKS (1 << 1)
#define FUSE_FILE_OPS (1 << 2)
#define FUSE_ATOMIC_O_TRUNC (1 << 3)
#define FUSE_EXPORT_SUPPORT (1 << 4)
#define FUSE_BIG_WRITES (1 << 5)
#define FUSE_DONT_MASK (1 << 6)
#define FUSE_FLOCK_LOCKS (1 << 10)
/**
* CUSE INIT request/reply flags
*
* CUSE_UNRESTRICTED_IOCTL: use unrestricted ioctl
*/
#define CUSE_UNRESTRICTED_IOCTL (1 << 0)
/**
* Release flags
*/
#define FUSE_RELEASE_FLUSH (1 << 0)
#define FUSE_RELEASE_FLOCK_UNLOCK (1 << 1)
/**
* Getattr flags
*/
#define FUSE_GETATTR_FH (1 << 0)
/**
* Lock flags
*/
#define FUSE_LK_FLOCK (1 << 0)
/**
* WRITE flags
*
* FUSE_WRITE_CACHE: delayed write from page cache, file handle is guessed
* FUSE_WRITE_LOCKOWNER: lock_owner field is valid
*/
#define FUSE_WRITE_CACHE (1 << 0)
#define FUSE_WRITE_LOCKOWNER (1 << 1)
/**
* Read flags
*/
#define FUSE_READ_LOCKOWNER (1 << 1)
/**
* Ioctl flags
*
* FUSE_IOCTL_COMPAT: 32bit compat ioctl on 64bit machine
* FUSE_IOCTL_UNRESTRICTED: not restricted to well-formed ioctls, retry allowed
* FUSE_IOCTL_RETRY: retry with new iovecs
* FUSE_IOCTL_32BIT: 32bit ioctl
* FUSE_IOCTL_DIR: is a directory
*
* FUSE_IOCTL_MAX_IOV: maximum of in_iovecs + out_iovecs
*/
#define FUSE_IOCTL_COMPAT (1 << 0)
#define FUSE_IOCTL_UNRESTRICTED (1 << 1)
#define FUSE_IOCTL_RETRY (1 << 2)
#define FUSE_IOCTL_32BIT (1 << 3)
#define FUSE_IOCTL_DIR (1 << 4)
#define FUSE_IOCTL_MAX_IOV 256
/**
* Poll flags
*
* FUSE_POLL_SCHEDULE_NOTIFY: request poll notify
*/
#define FUSE_POLL_SCHEDULE_NOTIFY (1 << 0)
enum fuse_opcode {
FUSE_LOOKUP = 1,
FUSE_FORGET = 2, /* no reply */
FUSE_GETATTR = 3,
FUSE_SETATTR = 4,
FUSE_READLINK = 5,
FUSE_SYMLINK = 6,
FUSE_MKNOD = 8,
FUSE_MKDIR = 9,
FUSE_UNLINK = 10,
FUSE_RMDIR = 11,
FUSE_RENAME = 12,
FUSE_LINK = 13,
FUSE_OPEN = 14,
FUSE_READ = 15,
FUSE_WRITE = 16,
FUSE_STATFS = 17,
FUSE_RELEASE = 18,
FUSE_FSYNC = 20,
FUSE_SETXATTR = 21,
FUSE_GETXATTR = 22,
FUSE_LISTXATTR = 23,
FUSE_REMOVEXATTR = 24,
FUSE_FLUSH = 25,
FUSE_INIT = 26,
FUSE_OPENDIR = 27,
FUSE_READDIR = 28,
FUSE_RELEASEDIR = 29,
FUSE_FSYNCDIR = 30,
FUSE_GETLK = 31,
FUSE_SETLK = 32,
FUSE_SETLKW = 33,
FUSE_ACCESS = 34,
FUSE_CREATE = 35,
FUSE_INTERRUPT = 36,
FUSE_BMAP = 37,
FUSE_DESTROY = 38,
FUSE_IOCTL = 39,
FUSE_POLL = 40,
FUSE_NOTIFY_REPLY = 41,
FUSE_BATCH_FORGET = 42,
/* CUSE specific operations */
CUSE_INIT = 4096,
};
enum fuse_notify_code {
FUSE_NOTIFY_POLL = 1,
FUSE_NOTIFY_INVAL_INODE = 2,
FUSE_NOTIFY_INVAL_ENTRY = 3,
FUSE_NOTIFY_STORE = 4,
FUSE_NOTIFY_RETRIEVE = 5,
FUSE_NOTIFY_DELETE = 6,
FUSE_NOTIFY_CODE_MAX,
};
/* The read buffer is required to be at least 8k, but may be much larger */
#define FUSE_MIN_READ_BUFFER 8192
#define FUSE_COMPAT_ENTRY_OUT_SIZE 120
struct fuse_entry_out {
__u64 nodeid; /* Inode ID */
__u64 generation; /* Inode generation: nodeid:gen must
be unique for the fs's lifetime */
__u64 entry_valid; /* Cache timeout for the name */
__u64 attr_valid; /* Cache timeout for the attributes */
__u32 entry_valid_nsec;
__u32 attr_valid_nsec;
struct fuse_attr attr;
};
struct fuse_forget_in {
__u64 nlookup;
};
struct fuse_forget_one {
__u64 nodeid;
__u64 nlookup;
};
struct fuse_batch_forget_in {
__u32 count;
__u32 dummy;
};
struct fuse_getattr_in {
__u32 getattr_flags;
__u32 dummy;
__u64 fh;
};
#define FUSE_COMPAT_ATTR_OUT_SIZE 96
struct fuse_attr_out {
__u64 attr_valid; /* Cache timeout for the attributes */
__u32 attr_valid_nsec;
__u32 dummy;
struct fuse_attr attr;
};
#define FUSE_COMPAT_MKNOD_IN_SIZE 8
struct fuse_mknod_in {
__u32 mode;
__u32 rdev;
__u32 umask;
__u32 padding;
};
struct fuse_mkdir_in {
__u32 mode;
__u32 umask;
};
struct fuse_rename_in {
__u64 newdir;
};
struct fuse_link_in {
__u64 oldnodeid;
};
struct fuse_setattr_in {
__u32 valid;
__u32 padding;
__u64 fh;
__u64 size;
__u64 lock_owner;
__u64 atime;
__u64 mtime;
__u64 unused2;
__u32 atimensec;
__u32 mtimensec;
__u32 unused3;
__u32 mode;
__u32 unused4;
__u32 uid;
__u32 gid;
__u32 unused5;
};
struct fuse_open_in {
__u32 flags;
__u32 unused;
};
struct fuse_create_in {
__u32 flags;
__u32 mode;
__u32 umask;
__u32 padding;
};
struct fuse_open_out {
__u64 fh;
__u32 open_flags;
__u32 padding;
};
struct fuse_release_in {
__u64 fh;
__u32 flags;
__u32 release_flags;
__u64 lock_owner;
};
struct fuse_flush_in {
__u64 fh;
__u32 unused;
__u32 padding;
__u64 lock_owner;
};
struct fuse_read_in {
__u64 fh;
__u64 offset;
__u32 size;
__u32 read_flags;
__u64 lock_owner;
__u32 flags;
__u32 padding;
};
#define FUSE_COMPAT_WRITE_IN_SIZE 24
struct fuse_write_in {
__u64 fh;
__u64 offset;
__u32 size;
__u32 write_flags;
__u64 lock_owner;
__u32 flags;
__u32 padding;
};
struct fuse_write_out {
__u32 size;
__u32 padding;
};
#define FUSE_COMPAT_STATFS_SIZE 48
struct fuse_statfs_out {
struct fuse_kstatfs st;
};
struct fuse_fsync_in {
__u64 fh;
__u32 fsync_flags;
__u32 padding;
};
struct fuse_setxattr_in {
__u32 size;
__u32 flags;
};
struct fuse_getxattr_in {
__u32 size;
__u32 padding;
};
struct fuse_getxattr_out {
__u32 size;
__u32 padding;
};
struct fuse_lk_in {
__u64 fh;
__u64 owner;
struct fuse_file_lock lk;
__u32 lk_flags;
__u32 padding;
};
struct fuse_lk_out {
struct fuse_file_lock lk;
};
struct fuse_access_in {
__u32 mask;
__u32 padding;
};
struct fuse_init_in {
__u32 major;
__u32 minor;
__u32 max_readahead;
__u32 flags;
};
struct fuse_init_out {
__u32 major;
__u32 minor;
__u32 max_readahead;
__u32 flags;
__u16 max_background;
__u16 congestion_threshold;
__u32 max_write;
};
#define CUSE_INIT_INFO_MAX 4096
struct cuse_init_in {
__u32 major;
__u32 minor;
__u32 unused;
__u32 flags;
};
struct cuse_init_out {
__u32 major;
__u32 minor;
__u32 unused;
__u32 flags;
__u32 max_read;
__u32 max_write;
__u32 dev_major; /* chardev major */
__u32 dev_minor; /* chardev minor */
__u32 spare[10];
};
struct fuse_interrupt_in {
__u64 unique;
};
struct fuse_bmap_in {
__u64 block;
__u32 blocksize;
__u32 padding;
};
struct fuse_bmap_out {
__u64 block;
};
struct fuse_ioctl_in {
__u64 fh;
__u32 flags;
__u32 cmd;
__u64 arg;
__u32 in_size;
__u32 out_size;
};
struct fuse_ioctl_iovec {
__u64 base;
__u64 len;
};
struct fuse_ioctl_out {
__s32 result;
__u32 flags;
__u32 in_iovs;
__u32 out_iovs;
};
struct fuse_poll_in {
__u64 fh;
__u64 kh;
__u32 flags;
__u32 padding;
};
struct fuse_poll_out {
__u32 revents;
__u32 padding;
};
struct fuse_notify_poll_wakeup_out {
__u64 kh;
};
struct fuse_in_header {
__u32 len;
__u32 opcode;
__u64 unique;
__u64 nodeid;
__u32 uid;
__u32 gid;
__u32 pid;
__u32 padding;
};
struct fuse_out_header {
__u32 len;
__s32 error;
__u64 unique;
};
struct fuse_dirent {
__u64 ino;
__u64 off;
__u32 namelen;
__u32 type;
char name[0];
};
#define FUSE_NAME_OFFSET offsetof(struct fuse_dirent, name)
#define FUSE_DIRENT_ALIGN(x) (((x) + sizeof(__u64) - 1) & ~(sizeof(__u64) - 1))
#define FUSE_DIRENT_SIZE(d) \
FUSE_DIRENT_ALIGN(FUSE_NAME_OFFSET + (d)->namelen)
struct fuse_notify_inval_inode_out {
__u64 ino;
__s64 off;
__s64 len;
};
struct fuse_notify_inval_entry_out {
__u64 parent;
__u32 namelen;
__u32 padding;
};
struct fuse_notify_delete_out {
__u64 parent;
__u64 child;
__u32 namelen;
__u32 padding;
};
struct fuse_notify_store_out {
__u64 nodeid;
__u64 offset;
__u32 size;
__u32 padding;
};
struct fuse_notify_retrieve_out {
__u64 notify_unique;
__u64 nodeid;
__u64 offset;
__u32 size;
__u32 padding;
};
/* Matches the size of fuse_write_in */
struct fuse_notify_retrieve_in {
__u64 dummy1;
__u64 offset;
__u32 size;
__u32 dummy2;
__u64 dummy3;
__u64 dummy4;
};
#endif /* _LINUX_FUSE_H */
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