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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);
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, void *calldata)
{
struct nfs_unlinkdata *data = calldata;
struct dentry *dir = data->dir;
struct rpc_message msg = {
.rpc_cred = data->cred,
};
int status = -ENOENT;
if (!data->name.len)
goto out_err;
status = NFS_PROTO(dir->d_inode)->unlink_setup(&msg, dir, &data->name);
if (status < 0)
goto out_err;
nfs_begin_data_update(dir->d_inode);
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, void *calldata)
{
struct nfs_unlinkdata *data = calldata;
struct dentry *dir = data->dir;
struct inode *dir_i;
if (!dir)
return;
dir_i = dir->d_inode;
nfs_end_data_update(dir_i);
if (NFS_PROTO(dir_i)->unlink_done(dir, task))
return;
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(void *calldata)
{
struct nfs_unlinkdata *data = calldata;
nfs_put_unlinkdata(data);
}
static const struct rpc_call_ops nfs_unlink_ops = {
.rpc_call_prepare = nfs_async_unlink_init,
.rpc_call_done = nfs_async_unlink_done,
.rpc_release = nfs_async_unlink_release,
};
/**
* nfs_async_unlink - asynchronous unlinking of a file
* @dentry: dentry to unlink
*/
int
nfs_async_unlink(struct dentry *dentry)
{
struct dentry *dir = dentry->d_parent;
struct nfs_unlinkdata *data;
struct rpc_clnt *clnt = NFS_CLIENT(dir->d_inode);
int status = -ENOMEM;
data = kzalloc(sizeof(*data), GFP_KERNEL);
if (!data)
goto out;
data->cred = rpcauth_lookupcred(clnt->cl_auth, 0);
if (IS_ERR(data->cred)) {
status = PTR_ERR(data->cred);
goto out_free;
}
data->dir = dget(dir);
data->dentry = dentry;
data->next = nfs_deletes;
nfs_deletes = data;
data->count = 1;
rpc_init_task(&data->task, clnt, RPC_TASK_ASYNC, &nfs_unlink_ops, data);
spin_lock(&dentry->d_lock);
dentry->d_flags |= DCACHE_NFSFS_RENAMED;
spin_unlock(&dentry->d_lock);
rpc_sleep_on(&nfs_delete_queue, &data->task, NULL, NULL);
status = 0;
out:
return status;
out_free:
kfree(data);
return status;
}
/**
* nfs_complete_unlink - 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);
spin_lock(&dentry->d_lock);
dentry->d_flags &= ~DCACHE_NFSFS_RENAMED;
spin_unlock(&dentry->d_lock);
rpc_wake_up_task(&data->task);
nfs_put_unlinkdata(data);
}
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