[net-next-2.6.git] / fs / nfs / unlink.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"
#include "nfs4_fs.h"

struct nfs_unlinkdata {
	struct hlist_node list;
	struct nfs_removeargs args;
	struct nfs_removeres res;
	struct inode *dir;
	struct rpc_cred	*cred;
	struct nfs_fattr dir_attr;
};

/**
 * 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))
		nfs_restart_rpc(task, NFS_SERVER(dir)->nfs_client);
}

/**
 * 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);
}

#if defined(CONFIG_NFS_V4_1)
void nfs_unlink_prepare(struct rpc_task *task, void *calldata)
{
	struct nfs_unlinkdata *data = calldata;
	struct nfs_server *server = NFS_SERVER(data->dir);

	if (nfs4_setup_sequence(server, &data->args.seq_args,
				&data->res.seq_res, 1, task))
		return;
	rpc_call_start(task);
}
#endif /* CONFIG_NFS_V4_1 */

static const struct rpc_call_ops nfs_unlink_ops = {
	.rpc_call_done = nfs_async_unlink_done,
	.rpc_release = nfs_async_unlink_release,
#if defined(CONFIG_NFS_V4_1)
	.rpc_call_prepare = nfs_unlink_prepare,
#endif /* CONFIG_NFS_V4_1 */
};

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;
	}
	data->res.seq_res.sr_slotid = NFS4_MAX_SLOT_TABLE;
	data->res.dir_attr = &data->dir_attr;

	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);
}
Commit	Line	Data
1da177e4 LT	1	/*
	2	* linux/fs/nfs/unlink.c
	3	*
	4	* nfs sillydelete handling
	5	*
1da177e4 LT	6	*/
	7
	8	#include <linux/slab.h>
	9	#include <linux/string.h>
	10	#include <linux/dcache.h>
	11	#include <linux/sunrpc/sched.h>
	12	#include <linux/sunrpc/clnt.h>
	13	#include <linux/nfs_fs.h>
b35e7041 LT	14	#include <linux/sched.h>
b35e7041 LT	15	#include <linux/wait.h>
1da177e4	16
ef818a28	17	#include "internal.h"
472cfbd9	18	#include "nfs4_fs.h"
ef818a28	19
1da177e4	20	struct nfs_unlinkdata {
565277f6	21	struct hlist_node list;
e4eff1a6 TM	22	struct nfs_removeargs args;
	23	struct nfs_removeres res;
	24	struct inode *dir;
1da177e4	25	struct rpc_cred *cred;
d346890b	26	struct nfs_fattr dir_attr;
1da177e4 LT	27	};
1da177e4 LT	28
1da177e4	29	/**
e4eff1a6	30	* nfs_free_unlinkdata - release data from a sillydelete operation.
1da177e4 LT	31	* @data: pointer to unlink structure.
	32	*/
	33	static void
e4eff1a6	34	nfs_free_unlinkdata(struct nfs_unlinkdata *data)
1da177e4	35	{
e4eff1a6 TM	36	iput(data->dir);
	37	put_rpccred(data->cred);
	38	kfree(data->args.name.name);
	39	kfree(data);
1da177e4 LT	40	}
	41
	42	#define NAME_ALLOC_LEN(len) ((len+16) & ~15)
	43	/**
	44	* nfs_copy_dname - copy dentry name to data structure
	45	* @dentry: pointer to dentry
	46	* @data: nfs_unlinkdata
	47	*/
e4eff1a6	48	static int nfs_copy_dname(struct dentry dentry, struct nfs_unlinkdata data)
1da177e4 LT	49	{
	50	char *str;
	51	int len = dentry->d_name.len;
	52
e4eff1a6	53	str = kmemdup(dentry->d_name.name, NAME_ALLOC_LEN(len), GFP_KERNEL);
1da177e4	54	if (!str)
e4eff1a6 TM	55	return -ENOMEM;
	56	data->args.name.len = len;
	57	data->args.name.name = str;
	58	return 0;
1da177e4 LT	59	}
1da177e4 LT	60
565277f6 TM	61	static void nfs_free_dname(struct nfs_unlinkdata *data)
	62	{
	63	kfree(data->args.name.name);
	64	data->args.name.name = NULL;
	65	data->args.name.len = 0;
	66	}
	67
	68	static void nfs_dec_sillycount(struct inode *dir)
	69	{
	70	struct nfs_inode *nfsi = NFS_I(dir);
	71	if (atomic_dec_return(&nfsi->silly_count) == 1)
	72	wake_up(&nfsi->waitqueue);
	73	}
	74
1da177e4 LT	75	/**
	76	* nfs_async_unlink_done - Sillydelete post-processing
	77	* @task: rpc_task of the sillydelete
	78	*
	79	* Do the directory attribute update.
	80	*/
963d8fe5	81	static void nfs_async_unlink_done(struct rpc_task task, void calldata)
1da177e4	82	{
e4eff1a6 TM	83	struct nfs_unlinkdata *data = calldata;
	84	struct inode *dir = data->dir;
	85
	86	if (!NFS_PROTO(dir)->unlink_done(task, dir))
0110ee15	87	nfs_restart_rpc(task, NFS_SERVER(dir)->nfs_client);
1da177e4 LT	88	}
	89
	90	/**
	91	* nfs_async_unlink_release - Release the sillydelete data.
	92	* @task: rpc_task of the sillydelete
	93	*
	94	* We need to call nfs_put_unlinkdata as a 'tk_release' task since the
	95	* rpc_task would be freed too.
	96	*/
963d8fe5	97	static void nfs_async_unlink_release(void *calldata)
1da177e4	98	{
963d8fe5	99	struct nfs_unlinkdata *data = calldata;
744d18db	100	struct super_block *sb = data->dir->i_sb;
565277f6 TM	101
565277f6 TM	102	nfs_dec_sillycount(data->dir);
e4eff1a6	103	nfs_free_unlinkdata(data);
1daef0a8	104	nfs_sb_deactive(sb);
1da177e4 LT	105	}
1da177e4 LT	106
472cfbd9 AA	107	#if defined(CONFIG_NFS_V4_1)
	108	void nfs_unlink_prepare(struct rpc_task task, void calldata)
	109	{
	110	struct nfs_unlinkdata *data = calldata;
	111	struct nfs_server *server = NFS_SERVER(data->dir);
	112
035168ab	113	if (nfs4_setup_sequence(server, &data->args.seq_args,
472cfbd9 AA	114	&data->res.seq_res, 1, task))
	115	return;
	116	rpc_call_start(task);
	117	}
	118	#endif /* CONFIG_NFS_V4_1 */
	119
963d8fe5 TM	120	static const struct rpc_call_ops nfs_unlink_ops = {
	121	.rpc_call_done = nfs_async_unlink_done,
	122	.rpc_release = nfs_async_unlink_release,
472cfbd9 AA	123	#if defined(CONFIG_NFS_V4_1)
	124	.rpc_call_prepare = nfs_unlink_prepare,
	125	#endif /* CONFIG_NFS_V4_1 */
963d8fe5 TM	126	};
963d8fe5 TM	127
565277f6	128	static int nfs_do_call_unlink(struct dentry parent, struct inode dir, struct nfs_unlinkdata *data)
e4eff1a6	129	{
5138fde0 TM	130	struct rpc_message msg = {
	131	.rpc_argp = &data->args,
	132	.rpc_resp = &data->res,
	133	.rpc_cred = data->cred,
	134	};
c970aa85	135	struct rpc_task_setup task_setup_data = {
5138fde0	136	.rpc_message = &msg,
c970aa85 TM	137	.callback_ops = &nfs_unlink_ops,
c970aa85 TM	138	.callback_data = data,
1daef0a8	139	.workqueue = nfsiod_workqueue,
c970aa85 TM	140	.flags = RPC_TASK_ASYNC,
c970aa85 TM	141	};
e4eff1a6	142	struct rpc_task *task;
565277f6 TM	143	struct dentry *alias;
	144
	145	alias = d_lookup(parent, &data->args.name);
	146	if (alias != NULL) {
	147	int ret = 0;
609005c3	148
565277f6 TM	149	/*
	150	* Hey, we raced with lookup... See if we need to transfer
	151	* the sillyrename information to the aliased dentry.
	152	*/
	153	nfs_free_dname(data);
	154	spin_lock(&alias->d_lock);
609005c3 TM	155	if (alias->d_inode != NULL &&
609005c3 TM	156	!(alias->d_flags & DCACHE_NFSFS_RENAMED)) {
565277f6	157	alias->d_fsdata = data;
fccca7fc	158	alias->d_flags \|= DCACHE_NFSFS_RENAMED;
565277f6 TM	159	ret = 1;
	160	}
	161	spin_unlock(&alias->d_lock);
	162	nfs_dec_sillycount(dir);
	163	dput(alias);
	164	return ret;
	165	}
	166	data->dir = igrab(dir);
	167	if (!data->dir) {
	168	nfs_dec_sillycount(dir);
	169	return 0;
	170	}
1daef0a8	171	nfs_sb_active(dir->i_sb);
565277f6	172	data->args.fh = NFS_FH(dir);
d346890b	173	nfs_fattr_init(data->res.dir_attr);
565277f6	174
5138fde0	175	NFS_PROTO(dir)->unlink_setup(&msg, dir);
c970aa85	176
5138fde0	177	task_setup_data.rpc_client = NFS_CLIENT(dir);
c970aa85	178	task = rpc_run_task(&task_setup_data);
565277f6 TM	179	if (!IS_ERR(task))
	180	rpc_put_task(task);
	181	return 1;
	182	}
	183
	184	static int nfs_call_unlink(struct dentry dentry, struct nfs_unlinkdata data)
	185	{
e4eff1a6 TM	186	struct dentry *parent;
e4eff1a6 TM	187	struct inode *dir;
565277f6	188	int ret = 0;
e4eff1a6	189
e4eff1a6 TM	190
	191	parent = dget_parent(dentry);
	192	if (parent == NULL)
	193	goto out_free;
565277f6	194	dir = parent->d_inode;
55b70a03	195	if (nfs_copy_dname(dentry, data) != 0)
565277f6 TM	196	goto out_dput;
	197	/* Non-exclusive lock protects against concurrent lookup() calls */
	198	spin_lock(&dir->i_lock);
	199	if (atomic_inc_not_zero(&NFS_I(dir)->silly_count) == 0) {
	200	/* Deferred delete */
	201	hlist_add_head(&data->list, &NFS_I(dir)->silly_list);
	202	spin_unlock(&dir->i_lock);
	203	ret = 1;
	204	goto out_dput;
	205	}
	206	spin_unlock(&dir->i_lock);
	207	ret = nfs_do_call_unlink(parent, dir, data);
	208	out_dput:
e4eff1a6	209	dput(parent);
565277f6 TM	210	out_free:
	211	return ret;
	212	}
e4eff1a6	213
565277f6 TM	214	void nfs_block_sillyrename(struct dentry *dentry)
	215	{
	216	struct nfs_inode *nfsi = NFS_I(dentry->d_inode);
e4eff1a6	217
565277f6 TM	218	wait_event(nfsi->waitqueue, atomic_cmpxchg(&nfsi->silly_count, 1, 0) == 1);
	219	}
	220
	221	void nfs_unblock_sillyrename(struct dentry *dentry)
	222	{
	223	struct inode *dir = dentry->d_inode;
	224	struct nfs_inode *nfsi = NFS_I(dir);
	225	struct nfs_unlinkdata *data;
	226
	227	atomic_inc(&nfsi->silly_count);
	228	spin_lock(&dir->i_lock);
	229	while (!hlist_empty(&nfsi->silly_list)) {
	230	if (!atomic_inc_not_zero(&nfsi->silly_count))
	231	break;
	232	data = hlist_entry(nfsi->silly_list.first, struct nfs_unlinkdata, list);
	233	hlist_del(&data->list);
	234	spin_unlock(&dir->i_lock);
	235	if (nfs_do_call_unlink(dentry, dir, data) == 0)
	236	nfs_free_unlinkdata(data);
	237	spin_lock(&dir->i_lock);
	238	}
	239	spin_unlock(&dir->i_lock);
e4eff1a6 TM	240	}
e4eff1a6 TM	241
1da177e4 LT	242	/**
1da177e4 LT	243	* nfs_async_unlink - asynchronous unlinking of a file
e4eff1a6	244	* @dir: parent directory of dentry
1da177e4 LT	245	* @dentry: dentry to unlink
	246	*/
	247	int
e4eff1a6	248	nfs_async_unlink(struct inode dir, struct dentry dentry)
1da177e4	249	{
e4eff1a6 TM	250	struct nfs_unlinkdata *data;
e4eff1a6 TM	251	int status = -ENOMEM;
1da177e4	252
bd647545	253	data = kzalloc(sizeof(*data), GFP_KERNEL);
e4eff1a6	254	if (data == NULL)
1da177e4	255	goto out;
1da177e4	256
98a8e323	257	data->cred = rpc_lookup_cred();
1da177e4 LT	258	if (IS_ERR(data->cred)) {
	259	status = PTR_ERR(data->cred);
	260	goto out_free;
	261	}
5f7dbd5c	262	data->res.seq_res.sr_slotid = NFS4_MAX_SLOT_TABLE;
d346890b	263	data->res.dir_attr = &data->dir_attr;
1da177e4	264
e4eff1a6	265	status = -EBUSY;
1da177e4	266	spin_lock(&dentry->d_lock);
e4eff1a6 TM	267	if (dentry->d_flags & DCACHE_NFSFS_RENAMED)
e4eff1a6 TM	268	goto out_unlock;
1da177e4	269	dentry->d_flags \|= DCACHE_NFSFS_RENAMED;
e4eff1a6	270	dentry->d_fsdata = data;
1da177e4	271	spin_unlock(&dentry->d_lock);
e4eff1a6 TM	272	return 0;
	273	out_unlock:
	274	spin_unlock(&dentry->d_lock);
	275	put_rpccred(data->cred);
1da177e4 LT	276	out_free:
1da177e4 LT	277	kfree(data);
e4eff1a6	278	out:
1da177e4 LT	279	return status;
	280	}
	281
	282	/**
	283	* nfs_complete_unlink - Initialize completion of the sillydelete
	284	* @dentry: dentry to delete
e4eff1a6	285	* @inode: inode
1da177e4 LT	286	*
	287	* Since we're most likely to be called by dentry_iput(), we
	288	* only use the dentry to find the sillydelete. We then copy the name
	289	* into the qstr.
	290	*/
	291	void
e4eff1a6	292	nfs_complete_unlink(struct dentry dentry, struct inode inode)
1da177e4	293	{
e4eff1a6	294	struct nfs_unlinkdata *data = NULL;
1da177e4	295
1da177e4	296	spin_lock(&dentry->d_lock);
e4eff1a6 TM	297	if (dentry->d_flags & DCACHE_NFSFS_RENAMED) {
	298	dentry->d_flags &= ~DCACHE_NFSFS_RENAMED;
	299	data = dentry->d_fsdata;
	300	}
1da177e4	301	spin_unlock(&dentry->d_lock);
e4eff1a6 TM	302
	303	if (data != NULL && (NFS_STALE(inode) \|\| !nfs_call_unlink(dentry, data)))
	304	nfs_free_unlinkdata(data);
1da177e4	305	}