[mirror_ubuntu-bionic-kernel.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"

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