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qemu-e2k/hw/9pfs/9p.h
Greg Kurz 0e44a0fd3f virtio-9p: add reset handler 
Virtio devices should implement the VirtIODevice->reset() function to
perform necessary cleanup actions and to bring the device to a quiescent
state.

In the case of the virtio-9p device, this means:
- emptying the list of active PDUs (i.e. draining all in-flight I/O)
- freeing all fids (i.e. close open file descriptors and free memory)

That's what this patch does.

The reset handler first waits for all active PDUs to complete. Since
completion happens in the QEMU global aio context, we just have to
loop around aio_poll() until the active list is empty.

The freeing part involves some actions to be performed on the backend,
like closing file descriptors or flushing extended attributes to the
underlying filesystem. The virtfs_reset() function already does the
job: it calls free_fid() for all open fids not involved in an ongoing
I/O operation. We are sure this is the case since we have drained
the PDU active list.

The current code implements all backend accesses with coroutines, but we
want to stay synchronous on the reset path. We can either change the
current code to be able to run when not in coroutine context, or create
a coroutine context and wait for virtfs_reset() to complete. This patch
goes for the latter because it results in simpler code.

Note that we also need to create a dummy PDU because it is also an API
to pass the FsContext pointer to all backend callbacks.

Signed-off-by: Greg Kurz <groug@kaod.org>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
2016-10-17 14:13:58 +02:00

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#ifndef QEMU_9P_H
#define QEMU_9P_H
#include <dirent.h>
#include <utime.h>
#include <sys/resource.h>
#include "fsdev/file-op-9p.h"
#include "fsdev/9p-iov-marshal.h"
#include "qemu/thread.h"
#include "qemu/coroutine.h"
enum {
P9_TLERROR = 6,
P9_RLERROR,
P9_TSTATFS = 8,
P9_RSTATFS,
P9_TLOPEN = 12,
P9_RLOPEN,
P9_TLCREATE = 14,
P9_RLCREATE,
P9_TSYMLINK = 16,
P9_RSYMLINK,
P9_TMKNOD = 18,
P9_RMKNOD,
P9_TRENAME = 20,
P9_RRENAME,
P9_TREADLINK = 22,
P9_RREADLINK,
P9_TGETATTR = 24,
P9_RGETATTR,
P9_TSETATTR = 26,
P9_RSETATTR,
P9_TXATTRWALK = 30,
P9_RXATTRWALK,
P9_TXATTRCREATE = 32,
P9_RXATTRCREATE,
P9_TREADDIR = 40,
P9_RREADDIR,
P9_TFSYNC = 50,
P9_RFSYNC,
P9_TLOCK = 52,
P9_RLOCK,
P9_TGETLOCK = 54,
P9_RGETLOCK,
P9_TLINK = 70,
P9_RLINK,
P9_TMKDIR = 72,
P9_RMKDIR,
P9_TRENAMEAT = 74,
P9_RRENAMEAT,
P9_TUNLINKAT = 76,
P9_RUNLINKAT,
P9_TVERSION = 100,
P9_RVERSION,
P9_TAUTH = 102,
P9_RAUTH,
P9_TATTACH = 104,
P9_RATTACH,
P9_TERROR = 106,
P9_RERROR,
P9_TFLUSH = 108,
P9_RFLUSH,
P9_TWALK = 110,
P9_RWALK,
P9_TOPEN = 112,
P9_ROPEN,
P9_TCREATE = 114,
P9_RCREATE,
P9_TREAD = 116,
P9_RREAD,
P9_TWRITE = 118,
P9_RWRITE,
P9_TCLUNK = 120,
P9_RCLUNK,
P9_TREMOVE = 122,
P9_RREMOVE,
P9_TSTAT = 124,
P9_RSTAT,
P9_TWSTAT = 126,
P9_RWSTAT,
};
/* qid.types */
enum {
P9_QTDIR = 0x80,
P9_QTAPPEND = 0x40,
P9_QTEXCL = 0x20,
P9_QTMOUNT = 0x10,
P9_QTAUTH = 0x08,
P9_QTTMP = 0x04,
P9_QTSYMLINK = 0x02,
P9_QTLINK = 0x01,
P9_QTFILE = 0x00,
};
enum p9_proto_version {
V9FS_PROTO_2000U = 0x01,
V9FS_PROTO_2000L = 0x02,
};
#define P9_NOTAG (u16)(~0)
#define P9_NOFID (u32)(~0)
#define P9_MAXWELEM 16
#define FID_REFERENCED 0x1
#define FID_NON_RECLAIMABLE 0x2
static inline char *rpath(FsContext *ctx, const char *path)
{
return g_strdup_printf("%s/%s", ctx->fs_root, path);
}
/*
* ample room for Twrite/Rread header
* size[4] Tread/Twrite tag[2] fid[4] offset[8] count[4]
*/
#define P9_IOHDRSZ 24
typedef struct V9fsPDU V9fsPDU;
struct V9fsState;
struct V9fsPDU
{
uint32_t size;
uint16_t tag;
uint8_t id;
uint8_t cancelled;
CoQueue complete;
struct V9fsState *s;
QLIST_ENTRY(V9fsPDU) next;
uint32_t idx;
};
/* FIXME
* 1) change user needs to set groups and stuff
*/
#define MAX_REQ 128
#define MAX_TAG_LEN 32
#define BUG_ON(cond) assert(!(cond))
typedef struct V9fsFidState V9fsFidState;
enum {
P9_FID_NONE = 0,
P9_FID_FILE,
P9_FID_DIR,
P9_FID_XATTR,
};
typedef struct V9fsConf
{
/* tag name for the device */
char *tag;
char *fsdev_id;
} V9fsConf;
typedef struct V9fsXattr
{
int64_t copied_len;
int64_t len;
void *value;
V9fsString name;
int flags;
} V9fsXattr;
typedef struct V9fsDir {
DIR *stream;
QemuMutex readdir_mutex;
} V9fsDir;
static inline void v9fs_readdir_lock(V9fsDir *dir)
{
qemu_mutex_lock(&dir->readdir_mutex);
}
static inline void v9fs_readdir_unlock(V9fsDir *dir)
{
qemu_mutex_unlock(&dir->readdir_mutex);
}
static inline void v9fs_readdir_init(V9fsDir *dir)
{
qemu_mutex_init(&dir->readdir_mutex);
}
/*
* Filled by fs driver on open and other
* calls.
*/
union V9fsFidOpenState {
int fd;
V9fsDir dir;
V9fsXattr xattr;
/*
* private pointer for fs drivers, that
* have its own internal representation of
* open files.
*/
void *private;
};
struct V9fsFidState
{
int fid_type;
int32_t fid;
V9fsPath path;
V9fsFidOpenState fs;
V9fsFidOpenState fs_reclaim;
int flags;
int open_flags;
uid_t uid;
int ref;
int clunked;
V9fsFidState *next;
V9fsFidState *rclm_lst;
};
typedef struct V9fsState
{
QLIST_HEAD(, V9fsPDU) free_list;
QLIST_HEAD(, V9fsPDU) active_list;
V9fsFidState *fid_list;
FileOperations *ops;
FsContext ctx;
char *tag;
enum p9_proto_version proto_version;
int32_t msize;
/*
* lock ensuring atomic path update
* on rename.
*/
CoRwlock rename_lock;
int32_t root_fid;
Error *migration_blocker;
V9fsConf fsconf;
V9fsQID root_qid;
} V9fsState;
/* 9p2000.L open flags */
#define P9_DOTL_RDONLY 00000000
#define P9_DOTL_WRONLY 00000001
#define P9_DOTL_RDWR 00000002
#define P9_DOTL_NOACCESS 00000003
#define P9_DOTL_CREATE 00000100
#define P9_DOTL_EXCL 00000200
#define P9_DOTL_NOCTTY 00000400
#define P9_DOTL_TRUNC 00001000
#define P9_DOTL_APPEND 00002000
#define P9_DOTL_NONBLOCK 00004000
#define P9_DOTL_DSYNC 00010000
#define P9_DOTL_FASYNC 00020000
#define P9_DOTL_DIRECT 00040000
#define P9_DOTL_LARGEFILE 00100000
#define P9_DOTL_DIRECTORY 00200000
#define P9_DOTL_NOFOLLOW 00400000
#define P9_DOTL_NOATIME 01000000
#define P9_DOTL_CLOEXEC 02000000
#define P9_DOTL_SYNC 04000000
/* 9p2000.L at flags */
#define P9_DOTL_AT_REMOVEDIR 0x200
/* 9P2000.L lock type */
#define P9_LOCK_TYPE_RDLCK 0
#define P9_LOCK_TYPE_WRLCK 1
#define P9_LOCK_TYPE_UNLCK 2
#define P9_LOCK_SUCCESS 0
#define P9_LOCK_BLOCKED 1
#define P9_LOCK_ERROR 2
#define P9_LOCK_GRACE 3
#define P9_LOCK_FLAGS_BLOCK 1
#define P9_LOCK_FLAGS_RECLAIM 2
typedef struct V9fsFlock
{
uint8_t type;
uint32_t flags;
uint64_t start; /* absolute offset */
uint64_t length;
uint32_t proc_id;
V9fsString client_id;
} V9fsFlock;
typedef struct V9fsGetlock
{
uint8_t type;
uint64_t start; /* absolute offset */
uint64_t length;
uint32_t proc_id;
V9fsString client_id;
} V9fsGetlock;
extern int open_fd_hw;
extern int total_open_fd;
static inline void v9fs_path_write_lock(V9fsState *s)
{
if (s->ctx.export_flags & V9FS_PATHNAME_FSCONTEXT) {
qemu_co_rwlock_wrlock(&s->rename_lock);
}
}
static inline void v9fs_path_read_lock(V9fsState *s)
{
if (s->ctx.export_flags & V9FS_PATHNAME_FSCONTEXT) {
qemu_co_rwlock_rdlock(&s->rename_lock);
}
}
static inline void v9fs_path_unlock(V9fsState *s)
{
if (s->ctx.export_flags & V9FS_PATHNAME_FSCONTEXT) {
qemu_co_rwlock_unlock(&s->rename_lock);
}
}
static inline uint8_t v9fs_request_cancelled(V9fsPDU *pdu)
{
return pdu->cancelled;
}
void coroutine_fn v9fs_reclaim_fd(V9fsPDU *pdu);
void v9fs_path_init(V9fsPath *path);
void v9fs_path_free(V9fsPath *path);
void v9fs_path_sprintf(V9fsPath *path, const char *fmt, ...);
void v9fs_path_copy(V9fsPath *lhs, V9fsPath *rhs);
int v9fs_name_to_path(V9fsState *s, V9fsPath *dirpath,
const char *name, V9fsPath *path);
int v9fs_device_realize_common(V9fsState *s, Error **errp);
void v9fs_device_unrealize_common(V9fsState *s, Error **errp);
ssize_t pdu_marshal(V9fsPDU *pdu, size_t offset, const char *fmt, ...);
ssize_t pdu_unmarshal(V9fsPDU *pdu, size_t offset, const char *fmt, ...);
V9fsPDU *pdu_alloc(V9fsState *s);
void pdu_free(V9fsPDU *pdu);
void pdu_submit(V9fsPDU *pdu);
void v9fs_reset(V9fsState *s);
#endif
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