Commit 37d1e4d9 authored by Paolo Bonzini's avatar Paolo Bonzini Committed by Stefan Hajnoczi
Browse files

nfs: do not use aio_context_acquire/release 



Now that all bottom halves and callbacks take care of taking the
AioContext lock, we can migrate some users away from it and to a
specific QemuMutex or CoMutex.

Protect libnfs calls with a QemuMutex.  Callbacks are invoked
using bottom halves, so we don't even have to drop it around
callback invocations.

Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
Message-id: 20170222180725.28611-3-pbonzini@redhat.com
Signed-off-by: default avatarStefan Hajnoczi <stefanha@redhat.com>
parent ba3186c4

block/nfs.c

+19 −4
Original line number Diff line number Diff line
@@ -54,6 +54,7 @@ typedef struct NFSClient { 
    int events;

    bool has_zero_init;

    AioContext *aio_context;

    QemuMutex mutex;

    blkcnt_t st_blocks;

    bool cache_used;

    NFSServer *server;
@@ -191,6 +192,7 @@ static void nfs_parse_filename(const char *filename, QDict *options, 
static void nfs_process_read(void *arg);

static void nfs_process_write(void *arg);



/* Called with QemuMutex held.  */

static void nfs_set_events(NFSClient *client)

{

    int ev = nfs_which_events(client->context);
@@ -209,20 +211,20 @@ static void nfs_process_read(void *arg) 
{

    NFSClient *client = arg;



    aio_context_acquire(client->aio_context);

    qemu_mutex_lock(&client->mutex);

    nfs_service(client->context, POLLIN);

    nfs_set_events(client);

    aio_context_release(client->aio_context);

    qemu_mutex_unlock(&client->mutex);

}



static void nfs_process_write(void *arg)

{

    NFSClient *client = arg;



    aio_context_acquire(client->aio_context);

    qemu_mutex_lock(&client->mutex);

    nfs_service(client->context, POLLOUT);

    nfs_set_events(client);

    aio_context_release(client->aio_context);

    qemu_mutex_unlock(&client->mutex);

}



static void nfs_co_init_task(BlockDriverState *bs, NFSRPC *task)
@@ -242,6 +244,7 @@ static void nfs_co_generic_bh_cb(void *opaque) 
    aio_co_wake(task->co);

}



/* Called (via nfs_service) with QemuMutex held.  */

static void

nfs_co_generic_cb(int ret, struct nfs_context *nfs, void *data,

                  void *private_data)
@@ -273,12 +276,15 @@ static int coroutine_fn nfs_co_preadv(BlockDriverState *bs, uint64_t offset, 
    nfs_co_init_task(bs, &task);

    task.iov = iov;



    qemu_mutex_lock(&client->mutex);

    if (nfs_pread_async(client->context, client->fh,

                        offset, bytes, nfs_co_generic_cb, &task) != 0) {

        qemu_mutex_unlock(&client->mutex);

        return -ENOMEM;

    }



    nfs_set_events(client);

    qemu_mutex_unlock(&client->mutex);

    while (!task.complete) {

        qemu_coroutine_yield();

    }
@@ -317,9 +323,11 @@ static int coroutine_fn nfs_co_pwritev(BlockDriverState *bs, uint64_t offset, 
        buf = iov->iov[0].iov_base;

    }



    qemu_mutex_lock(&client->mutex);

    if (nfs_pwrite_async(client->context, client->fh,

                         offset, bytes, buf,

                         nfs_co_generic_cb, &task) != 0) {

        qemu_mutex_unlock(&client->mutex);

        if (my_buffer) {

            g_free(buf);

        }
@@ -327,6 +335,7 @@ static int coroutine_fn nfs_co_pwritev(BlockDriverState *bs, uint64_t offset, 
    }



    nfs_set_events(client);

    qemu_mutex_unlock(&client->mutex);

    while (!task.complete) {

        qemu_coroutine_yield();

    }
@@ -349,12 +358,15 @@ static int coroutine_fn nfs_co_flush(BlockDriverState *bs) 


    nfs_co_init_task(bs, &task);



    qemu_mutex_lock(&client->mutex);

    if (nfs_fsync_async(client->context, client->fh, nfs_co_generic_cb,

                        &task) != 0) {

        qemu_mutex_unlock(&client->mutex);

        return -ENOMEM;

    }



    nfs_set_events(client);

    qemu_mutex_unlock(&client->mutex);

    while (!task.complete) {

        qemu_coroutine_yield();

    }
@@ -440,6 +452,7 @@ static void nfs_file_close(BlockDriverState *bs) 
{

    NFSClient *client = bs->opaque;

    nfs_client_close(client);

    qemu_mutex_destroy(&client->mutex);

}



static NFSServer *nfs_config(QDict *options, Error **errp)
@@ -647,6 +660,7 @@ static int nfs_file_open(BlockDriverState *bs, QDict *options, int flags, 
    if (ret < 0) {

        return ret;

    }

    qemu_mutex_init(&client->mutex);

    bs->total_sectors = ret;

    ret = 0;

    return ret;
@@ -702,6 +716,7 @@ static int nfs_has_zero_init(BlockDriverState *bs) 
    return client->has_zero_init;

}



/* Called (via nfs_service) with QemuMutex held.  */

static void

nfs_get_allocated_file_size_cb(int ret, struct nfs_context *nfs, void *data,

                               void *private_data)