linux/fs/nfs/unlink.c
Trond Myklebust 1daef0a868 NFS: Clean up nfs_sb_active/nfs_sb_deactive
Instead of causing umount requests to block on server->active_wq while the
asynchronous sillyrename deletes are executing, we can use the sb->s_active
counter to obtain a reference to the super_block, and then release that
reference in nfs_async_unlink_release().

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
2008-10-06 20:08:26 -04:00

286 lines
6.6 KiB
C

/*
* linux/fs/nfs/unlink.c
*
* nfs sillydelete handling
*
*/
#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>
#include <linux/sched.h>
#include <linux/wait.h>
#include "internal.h"
struct nfs_unlinkdata {
struct hlist_node list;
struct nfs_removeargs args;
struct nfs_removeres res;
struct inode *dir;
struct rpc_cred *cred;
};
/**
* nfs_free_unlinkdata - release data from a sillydelete operation.
* @data: pointer to unlink structure.
*/
static void
nfs_free_unlinkdata(struct nfs_unlinkdata *data)
{
iput(data->dir);
put_rpccred(data->cred);
kfree(data->args.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 int nfs_copy_dname(struct dentry *dentry, struct nfs_unlinkdata *data)
{
char *str;
int len = dentry->d_name.len;
str = kmemdup(dentry->d_name.name, NAME_ALLOC_LEN(len), GFP_KERNEL);
if (!str)
return -ENOMEM;
data->args.name.len = len;
data->args.name.name = str;
return 0;
}
static void nfs_free_dname(struct nfs_unlinkdata *data)
{
kfree(data->args.name.name);
data->args.name.name = NULL;
data->args.name.len = 0;
}
static void nfs_dec_sillycount(struct inode *dir)
{
struct nfs_inode *nfsi = NFS_I(dir);
if (atomic_dec_return(&nfsi->silly_count) == 1)
wake_up(&nfsi->waitqueue);
}
/**
* 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 inode *dir = data->dir;
if (!NFS_PROTO(dir)->unlink_done(task, dir))
rpc_restart_call(task);
}
/**
* 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;
struct super_block *sb = data->dir->i_sb;
nfs_dec_sillycount(data->dir);
nfs_free_unlinkdata(data);
nfs_sb_deactive(sb);
}
static const struct rpc_call_ops nfs_unlink_ops = {
.rpc_call_done = nfs_async_unlink_done,
.rpc_release = nfs_async_unlink_release,
};
static int nfs_do_call_unlink(struct dentry *parent, struct inode *dir, struct nfs_unlinkdata *data)
{
struct rpc_message msg = {
.rpc_argp = &data->args,
.rpc_resp = &data->res,
.rpc_cred = data->cred,
};
struct rpc_task_setup task_setup_data = {
.rpc_message = &msg,
.callback_ops = &nfs_unlink_ops,
.callback_data = data,
.workqueue = nfsiod_workqueue,
.flags = RPC_TASK_ASYNC,
};
struct rpc_task *task;
struct dentry *alias;
alias = d_lookup(parent, &data->args.name);
if (alias != NULL) {
int ret = 0;
/*
* Hey, we raced with lookup... See if we need to transfer
* the sillyrename information to the aliased dentry.
*/
nfs_free_dname(data);
spin_lock(&alias->d_lock);
if (alias->d_inode != NULL &&
!(alias->d_flags & DCACHE_NFSFS_RENAMED)) {
alias->d_fsdata = data;
alias->d_flags |= DCACHE_NFSFS_RENAMED;
ret = 1;
}
spin_unlock(&alias->d_lock);
nfs_dec_sillycount(dir);
dput(alias);
return ret;
}
data->dir = igrab(dir);
if (!data->dir) {
nfs_dec_sillycount(dir);
return 0;
}
nfs_sb_active(dir->i_sb);
data->args.fh = NFS_FH(dir);
nfs_fattr_init(&data->res.dir_attr);
NFS_PROTO(dir)->unlink_setup(&msg, dir);
task_setup_data.rpc_client = NFS_CLIENT(dir);
task = rpc_run_task(&task_setup_data);
if (!IS_ERR(task))
rpc_put_task(task);
return 1;
}
static int nfs_call_unlink(struct dentry *dentry, struct nfs_unlinkdata *data)
{
struct dentry *parent;
struct inode *dir;
int ret = 0;
parent = dget_parent(dentry);
if (parent == NULL)
goto out_free;
dir = parent->d_inode;
if (nfs_copy_dname(dentry, data) != 0)
goto out_dput;
/* Non-exclusive lock protects against concurrent lookup() calls */
spin_lock(&dir->i_lock);
if (atomic_inc_not_zero(&NFS_I(dir)->silly_count) == 0) {
/* Deferred delete */
hlist_add_head(&data->list, &NFS_I(dir)->silly_list);
spin_unlock(&dir->i_lock);
ret = 1;
goto out_dput;
}
spin_unlock(&dir->i_lock);
ret = nfs_do_call_unlink(parent, dir, data);
out_dput:
dput(parent);
out_free:
return ret;
}
void nfs_block_sillyrename(struct dentry *dentry)
{
struct nfs_inode *nfsi = NFS_I(dentry->d_inode);
wait_event(nfsi->waitqueue, atomic_cmpxchg(&nfsi->silly_count, 1, 0) == 1);
}
void nfs_unblock_sillyrename(struct dentry *dentry)
{
struct inode *dir = dentry->d_inode;
struct nfs_inode *nfsi = NFS_I(dir);
struct nfs_unlinkdata *data;
atomic_inc(&nfsi->silly_count);
spin_lock(&dir->i_lock);
while (!hlist_empty(&nfsi->silly_list)) {
if (!atomic_inc_not_zero(&nfsi->silly_count))
break;
data = hlist_entry(nfsi->silly_list.first, struct nfs_unlinkdata, list);
hlist_del(&data->list);
spin_unlock(&dir->i_lock);
if (nfs_do_call_unlink(dentry, dir, data) == 0)
nfs_free_unlinkdata(data);
spin_lock(&dir->i_lock);
}
spin_unlock(&dir->i_lock);
}
/**
* nfs_async_unlink - asynchronous unlinking of a file
* @dir: parent directory of dentry
* @dentry: dentry to unlink
*/
int
nfs_async_unlink(struct inode *dir, struct dentry *dentry)
{
struct nfs_unlinkdata *data;
int status = -ENOMEM;
data = kzalloc(sizeof(*data), GFP_KERNEL);
if (data == NULL)
goto out;
data->cred = rpc_lookup_cred();
if (IS_ERR(data->cred)) {
status = PTR_ERR(data->cred);
goto out_free;
}
status = -EBUSY;
spin_lock(&dentry->d_lock);
if (dentry->d_flags & DCACHE_NFSFS_RENAMED)
goto out_unlock;
dentry->d_flags |= DCACHE_NFSFS_RENAMED;
dentry->d_fsdata = data;
spin_unlock(&dentry->d_lock);
return 0;
out_unlock:
spin_unlock(&dentry->d_lock);
put_rpccred(data->cred);
out_free:
kfree(data);
out:
return status;
}
/**
* nfs_complete_unlink - Initialize completion of the sillydelete
* @dentry: dentry to delete
* @inode: inode
*
* 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 inode *inode)
{
struct nfs_unlinkdata *data = NULL;
spin_lock(&dentry->d_lock);
if (dentry->d_flags & DCACHE_NFSFS_RENAMED) {
dentry->d_flags &= ~DCACHE_NFSFS_RENAMED;
data = dentry->d_fsdata;
}
spin_unlock(&dentry->d_lock);
if (data != NULL && (NFS_STALE(inode) || !nfs_call_unlink(dentry, data)))
nfs_free_unlinkdata(data);
}