From 82cc3ee88ba238ec3ba96f4673d8a184588b82a4 Mon Sep 17 00:00:00 2001 From: "M. Mohan Kumar" Date: Wed, 8 Sep 2010 02:19:32 +0530 Subject: [PATCH] [virto-9p] Implement TLOCK Synopsis size[4] TLock tag[2] fid[4] flock[n] size[4] RLock tag[2] status[1] Description Tlock is used to acquire/release byte range posix locks on a file identified by given fid. The reply contains status of the lock request flock structure: type[1] - Type of lock: F_RDLCK, F_WRLCK, F_UNLCK flags[4] - Flags could be either of P9_LOCK_FLAGS_BLOCK(1) - Blocked lock request, if there is a conflicting lock exists, wait for that lock to be released. P9_LOCK_FLAGS_RECLAIM(2) - Reclaim lock request, used when client is trying to reclaim a lock after a server restrart (due to crash) start[8] - Starting offset for lock length[8] - Number of bytes to lock If length is 0, lock all bytes starting at the location 'start' through to the end of file pid[4] - PID of the process that wants to take lock client_id[4] - Unique client id status[1] - Status of the lock request, can be P9_LOCK_SUCCESS(0), P9_LOCK_BLOCKED(1), P9_LOCK_ERROR(2) or P9_LOCK_GRACE(3) P9_LOCK_SUCCESS - Request was successful P9_LOCK_BLOCKED - A conflicting lock is held by another process P9_LOCK_ERROR - Error while processing the lock request P9_LOCK_GRACE - Server is in grace period, it can't accept new lock requests in this period (except locks with P9_LOCK_FLAGS_RECLAIM flag set) Signed-off-by: M. Mohan Kumar Signed-off-by: Aneesh Kumar K.V Signed-off-by: Venkateswararao Jujjuri --- hw/virtio-9p-debug.c | 14 ++++++++++++++ hw/virtio-9p.c | 50 ++++++++++++++++++++++++++++++++++++++++++++++++++ hw/virtio-9p.h | 30 ++++++++++++++++++++++++++++++ 3 files changed, 94 insertions(+) diff --git a/hw/virtio-9p-debug.c b/hw/virtio-9p-debug.c index 6f6a0ec..045774f 100644 --- a/hw/virtio-9p-debug.c +++ b/hw/virtio-9p-debug.c @@ -588,6 +588,20 @@ void pprint_pdu(V9fsPDU *pdu) case P9_RXATTRCREATE: fprintf(llogfile, "RXATTRCREATE: ("); break; + case P9_TLOCK: + fprintf(llogfile, "TLOCK: ("); + pprint_int32(pdu, 0, &offset, "fid"); + pprint_int8(pdu, 0, &offset, ", type"); + pprint_int32(pdu, 0, &offset, ", flags"); + pprint_int64(pdu, 0, &offset, ", start"); + pprint_int64(pdu, 0, &offset, ", length"); + pprint_int32(pdu, 0, &offset, ", proc_id"); + pprint_str(pdu, 0, &offset, ", client_id"); + break; + case P9_RLOCK: + fprintf(llogfile, "RLOCK: ("); + pprint_int8(pdu, 0, &offset, "status"); + break; default: fprintf(llogfile, "unknown(%d): (", pdu->id); break; diff --git a/hw/virtio-9p.c b/hw/virtio-9p.c index 3379a30..20acb5b 100644 --- a/hw/virtio-9p.c +++ b/hw/virtio-9p.c @@ -3154,6 +3154,55 @@ out: qemu_free(vs); } +/* + * Implement posix byte range locking code + * Server side handling of locking code is very simple, because 9p server in + * QEMU can handle only one client. And most of the lock handling + * (like conflict, merging) etc is done by the VFS layer itself, so no need to + * do any thing in * qemu 9p server side lock code path. + * So when a TLOCK request comes, always return success + */ + +static void v9fs_lock(V9fsState *s, V9fsPDU *pdu) +{ + int32_t fid, err = 0; + V9fsLockState *vs; + + vs = qemu_mallocz(sizeof(*vs)); + vs->pdu = pdu; + vs->offset = 7; + + vs->flock = qemu_malloc(sizeof(*vs->flock)); + pdu_unmarshal(vs->pdu, vs->offset, "dbdqqds", &fid, &vs->flock->type, + &vs->flock->flags, &vs->flock->start, &vs->flock->length, + &vs->flock->proc_id, &vs->flock->client_id); + + vs->status = P9_LOCK_ERROR; + + /* We support only block flag now (that too ignored currently) */ + if (vs->flock->flags & ~P9_LOCK_FLAGS_BLOCK) { + err = -EINVAL; + goto out; + } + vs->fidp = lookup_fid(s, fid); + if (vs->fidp == NULL) { + err = -ENOENT; + goto out; + } + + err = v9fs_do_fstat(s, vs->fidp->fs.fd, &vs->stbuf); + if (err < 0) { + err = -errno; + goto out; + } + vs->status = P9_LOCK_SUCCESS; +out: + vs->offset += pdu_marshal(vs->pdu, vs->offset, "b", vs->status); + complete_pdu(s, vs->pdu, err); + qemu_free(vs->flock); + qemu_free(vs); +} + static void v9fs_mkdir_post_lstat(V9fsState *s, V9fsMkState *vs, int err) { if (err == -1) { @@ -3416,6 +3465,7 @@ static pdu_handler_t *pdu_handlers[] = { [P9_TXATTRCREATE] = v9fs_xattrcreate, [P9_TMKNOD] = v9fs_mknod, [P9_TRENAME] = v9fs_rename, + [P9_TLOCK] = v9fs_lock, [P9_TMKDIR] = v9fs_mkdir, [P9_TVERSION] = v9fs_version, [P9_TLOPEN] = v9fs_open, diff --git a/hw/virtio-9p.h b/hw/virtio-9p.h index 0816ad6..4555f39 100644 --- a/hw/virtio-9p.h +++ b/hw/virtio-9p.h @@ -37,6 +37,8 @@ enum { P9_RXATTRCREATE, P9_TREADDIR = 40, P9_RREADDIR, + P9_TLOCK = 52, + P9_RLOCK, P9_TLINK = 70, P9_RLINK, P9_TMKDIR = 72, @@ -434,6 +436,34 @@ typedef struct V9fsXattrState void *value; } V9fsXattrState; +#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 V9fsLockState +{ + V9fsPDU *pdu; + size_t offset; + int8_t status; + struct stat stbuf; + V9fsFidState *fidp; + V9fsFlock *flock; +} V9fsLockState; + extern size_t pdu_packunpack(void *addr, struct iovec *sg, int sg_count, size_t offset, size_t size, int pack); -- 2.7.4