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/*

 *  linux/fs/nfs/unlink.c

 *

 * nfs sillydelete handling

 *

 * NOTE: we rely on holding the BKL for list manipulation protection.

 */

#include <linux/slab.h>

#include <linux/string.h>

#include <linux/dcache.h>

#include <linux/sunrpc/sched.h>

#include <linux/sunrpc/clnt.h>

#include <linux/nfs_fs.h>

struct nfs_unlinkdata {

        struct nfs_unlinkdata   *next;

        struct dentry   *dir, *dentry;

        struct qstr     name;

        struct rpc_task task;

        struct rpc_cred *cred;

        unsigned int    count;

};

static struct nfs_unlinkdata    *nfs_deletes;

static RPC_WAITQ(nfs_delete_queue, "nfs_delete_queue");

/**

 * nfs_detach_unlinkdata - Remove asynchronous unlink from global list

 * @data: pointer to descriptor

 */

static inline void

nfs_detach_unlinkdata(struct nfs_unlinkdata *data)

{

        struct nfs_unlinkdata   **q;

        for (q = &nfs_deletes; *q != NULL; q = &((*q)->next)) {

                if (*q == data) {

                        *q = data->next;

                        break;

                }

        }

}

/**

 * nfs_put_unlinkdata - release data from a sillydelete operation.

 * @data: pointer to unlink structure.

 */

static void

nfs_put_unlinkdata(struct nfs_unlinkdata *data)

{

        if (--data->count == 0) {

                nfs_detach_unlinkdata(data);

                if (data->name.name != NULL)

                        kfree(data->name.name);

                kfree(data);

        }

}

#define NAME_ALLOC_LEN(len)     ((len+16) & ~15)

/**

 * nfs_copy_dname - copy dentry name to data structure

 * @dentry: pointer to dentry

 * @data: nfs_unlinkdata

 */

static inline void

nfs_copy_dname(struct dentry *dentry, struct nfs_unlinkdata *data)

{

        char            *str;

        int             len = dentry->d_name.len;

        str = kmalloc(NAME_ALLOC_LEN(len), GFP_KERNEL);

        if (!str)

                return;

        memcpy(str, dentry->d_name.name, len);

        if (!data->name.len) {

                data->name.len = len;

                data->name.name = str;

        } else

                kfree(str);

}

/**

 * nfs_async_unlink_init - Initialize the RPC info

 * @task: rpc_task of the sillydelete

 *

 * We delay initializing RPC info until after the call to dentry_iput()

 * in order to minimize races against rename().

 */

static void

nfs_async_unlink_init(struct rpc_task *task)

{

        struct nfs_unlinkdata   *data = (struct nfs_unlinkdata *)task->tk_calldata;

        struct dentry           *dir = data->dir;

        struct rpc_message      msg;

        int                     status = -ENOENT;

        if (!data->name.len)

                goto out_err;

        memset(&msg, 0, sizeof(msg));

        msg.rpc_cred = data->cred;

        status = NFS_PROTO(dir->d_inode)->unlink_setup(&msg, dir, &data->name);

        if (status < 0)

                goto out_err;

        rpc_call_setup(task, &msg, 0);

        return;

 out_err:

        rpc_exit(task, status);

}

/**

 * nfs_async_unlink_done - Sillydelete post-processing

 * @task: rpc_task of the sillydelete

 *

 * Do the directory attribute update.

 */

static void

nfs_async_unlink_done(struct rpc_task *task)

{

        struct nfs_unlinkdata   *data = (struct nfs_unlinkdata *)task->tk_calldata;

        struct dentry           *dir = data->dir;

        struct inode            *dir_i;

        if (nfs_async_handle_jukebox(task))

                return;

        if (!dir)

                return;

        dir_i = dir->d_inode;

        nfs_zap_caches(dir_i);

        NFS_PROTO(dir_i)->unlink_done(dir, &task->tk_msg);

        put_rpccred(data->cred);

        data->cred = NULL;

        dput(dir);

}

/**

 * nfs_async_unlink_release - Release the sillydelete data.

 * @task: rpc_task of the sillydelete

 *

 * We need to call nfs_put_unlinkdata as a 'tk_release' task since the

 * rpc_task would be freed too.

 */

static void

nfs_async_unlink_release(struct rpc_task *task)

{

        struct nfs_unlinkdata   *data = (struct nfs_unlinkdata *)task->tk_calldata;

        nfs_put_unlinkdata(data);

}

/**

 * nfs_async_unlink - asynchronous unlinking of a file

 * @dir: directory in which the file resides.

 * @name: name of the file to unlink.

 */

int

nfs_async_unlink(struct dentry *dentry)

{

        struct dentry   *dir = dentry->d_parent;

        struct nfs_unlinkdata   *data;

        struct rpc_task *task;

        struct rpc_clnt *clnt = NFS_CLIENT(dir->d_inode);

        int             status = -ENOMEM;

        data = kmalloc(sizeof(*data), GFP_KERNEL);

        if (!data)

                goto out;

        memset(data, 0, sizeof(*data));

        data->dir = dget(dir);

        data->dentry = dentry;

        data->next = nfs_deletes;

        nfs_deletes = data;

        data->count = 1;

        task = &data->task;

        rpc_init_task(task, clnt, nfs_async_unlink_done , RPC_TASK_ASYNC);

        task->tk_calldata = data;

        task->tk_action = nfs_async_unlink_init;

        task->tk_release = nfs_async_unlink_release;

        dentry->d_flags |= DCACHE_NFSFS_RENAMED;

        data->cred = rpcauth_lookupcred(clnt->cl_auth, 0);

        rpc_sleep_on(&nfs_delete_queue, task, NULL, NULL);

        status = 0;

 out:

        return status;

}

/**

 * nfs_complete_remove - Initialize completion of the sillydelete

 * @dentry: dentry to delete

 *

 * Since we're most likely to be called by dentry_iput(), we

 * only use the dentry to find the sillydelete. We then copy the name

 * into the qstr.

 */

void

nfs_complete_unlink(struct dentry *dentry)

{

        struct nfs_unlinkdata   *data;

        for(data = nfs_deletes; data != NULL; data = data->next) {

                if (dentry == data->dentry)

                        break;

        }

        if (!data)

                return;

        data->count++;

        nfs_copy_dname(dentry, data);

        dentry->d_flags &= ~DCACHE_NFSFS_RENAMED;

        if (data->task.tk_rpcwait == &nfs_delete_queue)

                rpc_wake_up_task(&data->task);

        nfs_put_unlinkdata(data);

}