[linux-block.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;
};

/**
 * 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))
		nfs4_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->nfs_client, &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;

	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;
1da177e4 LT	26	};
1da177e4 LT	27
1da177e4	28	/**
e4eff1a6	29	* nfs_free_unlinkdata - release data from a sillydelete operation.
1da177e4 LT	30	* @data: pointer to unlink structure.
	31	*/
	32	static void
e4eff1a6	33	nfs_free_unlinkdata(struct nfs_unlinkdata *data)
1da177e4	34	{
e4eff1a6 TM	35	iput(data->dir);
	36	put_rpccred(data->cred);
	37	kfree(data->args.name.name);
	38	kfree(data);
1da177e4 LT	39	}
	40
	41	#define NAME_ALLOC_LEN(len) ((len+16) & ~15)
	42	/**
	43	* nfs_copy_dname - copy dentry name to data structure
	44	* @dentry: pointer to dentry
	45	* @data: nfs_unlinkdata
	46	*/
e4eff1a6	47	static int nfs_copy_dname(struct dentry dentry, struct nfs_unlinkdata data)
1da177e4 LT	48	{
	49	char *str;
	50	int len = dentry->d_name.len;
	51
e4eff1a6	52	str = kmemdup(dentry->d_name.name, NAME_ALLOC_LEN(len), GFP_KERNEL);
1da177e4	53	if (!str)
e4eff1a6 TM	54	return -ENOMEM;
	55	data->args.name.len = len;
	56	data->args.name.name = str;
	57	return 0;
1da177e4 LT	58	}
1da177e4 LT	59
565277f6 TM	60	static void nfs_free_dname(struct nfs_unlinkdata *data)
	61	{
	62	kfree(data->args.name.name);
	63	data->args.name.name = NULL;
	64	data->args.name.len = 0;
	65	}
	66
	67	static void nfs_dec_sillycount(struct inode *dir)
	68	{
	69	struct nfs_inode *nfsi = NFS_I(dir);
	70	if (atomic_dec_return(&nfsi->silly_count) == 1)
	71	wake_up(&nfsi->waitqueue);
	72	}
	73
1da177e4 LT	74	/**
	75	* nfs_async_unlink_done - Sillydelete post-processing
	76	* @task: rpc_task of the sillydelete
	77	*
	78	* Do the directory attribute update.
	79	*/
963d8fe5	80	static void nfs_async_unlink_done(struct rpc_task task, void calldata)
1da177e4	81	{
e4eff1a6 TM	82	struct nfs_unlinkdata *data = calldata;
	83	struct inode *dir = data->dir;
	84
	85	if (!NFS_PROTO(dir)->unlink_done(task, dir))
eedc020e	86	nfs4_restart_rpc(task, NFS_SERVER(dir)->nfs_client);
1da177e4 LT	87	}
	88
	89	/**
	90	* nfs_async_unlink_release - Release the sillydelete data.
	91	* @task: rpc_task of the sillydelete
	92	*
	93	* We need to call nfs_put_unlinkdata as a 'tk_release' task since the
	94	* rpc_task would be freed too.
	95	*/
963d8fe5	96	static void nfs_async_unlink_release(void *calldata)
1da177e4	97	{
963d8fe5	98	struct nfs_unlinkdata *data = calldata;
744d18db	99	struct super_block *sb = data->dir->i_sb;
565277f6 TM	100
565277f6 TM	101	nfs_dec_sillycount(data->dir);
e4eff1a6	102	nfs_free_unlinkdata(data);
1daef0a8	103	nfs_sb_deactive(sb);
1da177e4 LT	104	}
1da177e4 LT	105
472cfbd9 AA	106	#if defined(CONFIG_NFS_V4_1)
	107	void nfs_unlink_prepare(struct rpc_task task, void calldata)
	108	{
	109	struct nfs_unlinkdata *data = calldata;
	110	struct nfs_server *server = NFS_SERVER(data->dir);
	111
	112	if (nfs4_setup_sequence(server->nfs_client, &data->args.seq_args,
	113	&data->res.seq_res, 1, task))
	114	return;
	115	rpc_call_start(task);
	116	}
	117	#endif /* CONFIG_NFS_V4_1 */
	118
963d8fe5 TM	119	static const struct rpc_call_ops nfs_unlink_ops = {
	120	.rpc_call_done = nfs_async_unlink_done,
	121	.rpc_release = nfs_async_unlink_release,
472cfbd9 AA	122	#if defined(CONFIG_NFS_V4_1)
	123	.rpc_call_prepare = nfs_unlink_prepare,
	124	#endif /* CONFIG_NFS_V4_1 */
963d8fe5 TM	125	};
963d8fe5 TM	126
565277f6	127	static int nfs_do_call_unlink(struct dentry parent, struct inode dir, struct nfs_unlinkdata *data)
e4eff1a6	128	{
5138fde0 TM	129	struct rpc_message msg = {
	130	.rpc_argp = &data->args,
	131	.rpc_resp = &data->res,
	132	.rpc_cred = data->cred,
	133	};
c970aa85	134	struct rpc_task_setup task_setup_data = {
5138fde0	135	.rpc_message = &msg,
c970aa85 TM	136	.callback_ops = &nfs_unlink_ops,
c970aa85 TM	137	.callback_data = data,
1daef0a8	138	.workqueue = nfsiod_workqueue,
c970aa85 TM	139	.flags = RPC_TASK_ASYNC,
c970aa85 TM	140	};
e4eff1a6	141	struct rpc_task *task;
565277f6 TM	142	struct dentry *alias;
	143
	144	alias = d_lookup(parent, &data->args.name);
	145	if (alias != NULL) {
	146	int ret = 0;
609005c3	147
565277f6 TM	148	/*
	149	* Hey, we raced with lookup... See if we need to transfer
	150	* the sillyrename information to the aliased dentry.
	151	*/
	152	nfs_free_dname(data);
	153	spin_lock(&alias->d_lock);
609005c3 TM	154	if (alias->d_inode != NULL &&
609005c3 TM	155	!(alias->d_flags & DCACHE_NFSFS_RENAMED)) {
565277f6	156	alias->d_fsdata = data;
fccca7fc	157	alias->d_flags \|= DCACHE_NFSFS_RENAMED;
565277f6 TM	158	ret = 1;
	159	}
	160	spin_unlock(&alias->d_lock);
	161	nfs_dec_sillycount(dir);
	162	dput(alias);
	163	return ret;
	164	}
	165	data->dir = igrab(dir);
	166	if (!data->dir) {
	167	nfs_dec_sillycount(dir);
	168	return 0;
	169	}
1daef0a8	170	nfs_sb_active(dir->i_sb);
565277f6 TM	171	data->args.fh = NFS_FH(dir);
	172	nfs_fattr_init(&data->res.dir_attr);
	173
5138fde0	174	NFS_PROTO(dir)->unlink_setup(&msg, dir);
c970aa85	175
5138fde0	176	task_setup_data.rpc_client = NFS_CLIENT(dir);
c970aa85	177	task = rpc_run_task(&task_setup_data);
565277f6 TM	178	if (!IS_ERR(task))
	179	rpc_put_task(task);
	180	return 1;
	181	}
	182
	183	static int nfs_call_unlink(struct dentry dentry, struct nfs_unlinkdata data)
	184	{
e4eff1a6 TM	185	struct dentry *parent;
e4eff1a6 TM	186	struct inode *dir;
565277f6	187	int ret = 0;
e4eff1a6	188
e4eff1a6 TM	189
	190	parent = dget_parent(dentry);
	191	if (parent == NULL)
	192	goto out_free;
565277f6	193	dir = parent->d_inode;
55b70a03	194	if (nfs_copy_dname(dentry, data) != 0)
565277f6 TM	195	goto out_dput;
	196	/* Non-exclusive lock protects against concurrent lookup() calls */
	197	spin_lock(&dir->i_lock);
	198	if (atomic_inc_not_zero(&NFS_I(dir)->silly_count) == 0) {
	199	/* Deferred delete */
	200	hlist_add_head(&data->list, &NFS_I(dir)->silly_list);
	201	spin_unlock(&dir->i_lock);
	202	ret = 1;
	203	goto out_dput;
	204	}
	205	spin_unlock(&dir->i_lock);
	206	ret = nfs_do_call_unlink(parent, dir, data);
	207	out_dput:
e4eff1a6	208	dput(parent);
565277f6 TM	209	out_free:
	210	return ret;
	211	}
e4eff1a6	212
565277f6 TM	213	void nfs_block_sillyrename(struct dentry *dentry)
	214	{
	215	struct nfs_inode *nfsi = NFS_I(dentry->d_inode);
e4eff1a6	216
565277f6 TM	217	wait_event(nfsi->waitqueue, atomic_cmpxchg(&nfsi->silly_count, 1, 0) == 1);
	218	}
	219
	220	void nfs_unblock_sillyrename(struct dentry *dentry)
	221	{
	222	struct inode *dir = dentry->d_inode;
	223	struct nfs_inode *nfsi = NFS_I(dir);
	224	struct nfs_unlinkdata *data;
	225
	226	atomic_inc(&nfsi->silly_count);
	227	spin_lock(&dir->i_lock);
	228	while (!hlist_empty(&nfsi->silly_list)) {
	229	if (!atomic_inc_not_zero(&nfsi->silly_count))
	230	break;
	231	data = hlist_entry(nfsi->silly_list.first, struct nfs_unlinkdata, list);
	232	hlist_del(&data->list);
	233	spin_unlock(&dir->i_lock);
	234	if (nfs_do_call_unlink(dentry, dir, data) == 0)
	235	nfs_free_unlinkdata(data);
	236	spin_lock(&dir->i_lock);
	237	}
	238	spin_unlock(&dir->i_lock);
e4eff1a6 TM	239	}
e4eff1a6 TM	240
1da177e4 LT	241	/**
1da177e4 LT	242	* nfs_async_unlink - asynchronous unlinking of a file
e4eff1a6	243	* @dir: parent directory of dentry
1da177e4 LT	244	* @dentry: dentry to unlink
	245	*/
	246	int
e4eff1a6	247	nfs_async_unlink(struct inode dir, struct dentry dentry)
1da177e4	248	{
e4eff1a6 TM	249	struct nfs_unlinkdata *data;
e4eff1a6 TM	250	int status = -ENOMEM;
1da177e4	251
bd647545	252	data = kzalloc(sizeof(*data), GFP_KERNEL);
e4eff1a6	253	if (data == NULL)
1da177e4	254	goto out;
1da177e4	255
98a8e323	256	data->cred = rpc_lookup_cred();
1da177e4 LT	257	if (IS_ERR(data->cred)) {
	258	status = PTR_ERR(data->cred);
	259	goto out_free;
	260	}
5f7dbd5c	261	data->res.seq_res.sr_slotid = NFS4_MAX_SLOT_TABLE;
1da177e4	262
e4eff1a6	263	status = -EBUSY;
1da177e4	264	spin_lock(&dentry->d_lock);
e4eff1a6 TM	265	if (dentry->d_flags & DCACHE_NFSFS_RENAMED)
e4eff1a6 TM	266	goto out_unlock;
1da177e4	267	dentry->d_flags \|= DCACHE_NFSFS_RENAMED;
e4eff1a6	268	dentry->d_fsdata = data;
1da177e4	269	spin_unlock(&dentry->d_lock);
e4eff1a6 TM	270	return 0;
	271	out_unlock:
	272	spin_unlock(&dentry->d_lock);
	273	put_rpccred(data->cred);
1da177e4 LT	274	out_free:
1da177e4 LT	275	kfree(data);
e4eff1a6	276	out:
1da177e4 LT	277	return status;
	278	}
	279
	280	/**
	281	* nfs_complete_unlink - Initialize completion of the sillydelete
	282	* @dentry: dentry to delete
e4eff1a6	283	* @inode: inode
1da177e4 LT	284	*
	285	* Since we're most likely to be called by dentry_iput(), we
	286	* only use the dentry to find the sillydelete. We then copy the name
	287	* into the qstr.
	288	*/
	289	void
e4eff1a6	290	nfs_complete_unlink(struct dentry dentry, struct inode inode)
1da177e4	291	{
e4eff1a6	292	struct nfs_unlinkdata *data = NULL;
1da177e4	293
1da177e4	294	spin_lock(&dentry->d_lock);
e4eff1a6 TM	295	if (dentry->d_flags & DCACHE_NFSFS_RENAMED) {
	296	dentry->d_flags &= ~DCACHE_NFSFS_RENAMED;
	297	data = dentry->d_fsdata;
	298	}
1da177e4	299	spin_unlock(&dentry->d_lock);
e4eff1a6 TM	300
	301	if (data != NULL && (NFS_STALE(inode) \|\| !nfs_call_unlink(dentry, data)))
	302	nfs_free_unlinkdata(data);
1da177e4	303	}