[linux.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 <linux/namei.h>

#include "internal.h"
#include "nfs4_fs.h"
#include "iostat.h"
#include "delegation.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
 */
static 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.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);
}

/* Cancel a queued async unlink. Called when a sillyrename run fails. */
static void
nfs_cancel_async_unlink(struct dentry *dentry)
{
	spin_lock(&dentry->d_lock);
	if (dentry->d_flags & DCACHE_NFSFS_RENAMED) {
		struct nfs_unlinkdata *data = dentry->d_fsdata;

		dentry->d_flags &= ~DCACHE_NFSFS_RENAMED;
		spin_unlock(&dentry->d_lock);
		nfs_free_unlinkdata(data);
		return;
	}
	spin_unlock(&dentry->d_lock);
}

struct nfs_renamedata {
	struct nfs_renameargs	args;
	struct nfs_renameres	res;
	struct rpc_cred		*cred;
	struct inode		*old_dir;
	struct dentry		*old_dentry;
	struct nfs_fattr	old_fattr;
	struct inode		*new_dir;
	struct dentry		*new_dentry;
	struct nfs_fattr	new_fattr;
};

/**
 * nfs_async_rename_done - Sillyrename post-processing
 * @task: rpc_task of the sillyrename
 * @calldata: nfs_renamedata for the sillyrename
 *
 * Do the directory attribute updates and the d_move
 */
static void nfs_async_rename_done(struct rpc_task *task, void *calldata)
{
	struct nfs_renamedata *data = calldata;
	struct inode *old_dir = data->old_dir;
	struct inode *new_dir = data->new_dir;

	if (!NFS_PROTO(old_dir)->rename_done(task, old_dir, new_dir)) {
		nfs_restart_rpc(task, NFS_SERVER(old_dir)->nfs_client);
		return;
	}

	if (task->tk_status != 0) {
		nfs_cancel_async_unlink(data->old_dentry);
		return;
	}

	nfs_set_verifier(data->old_dentry, nfs_save_change_attribute(old_dir));
	d_move(data->old_dentry, data->new_dentry);
}

/**
 * nfs_async_rename_release - Release the sillyrename data.
 * @calldata: the struct nfs_renamedata to be released
 */
static void nfs_async_rename_release(void *calldata)
{
	struct nfs_renamedata	*data = calldata;
	struct super_block *sb = data->old_dir->i_sb;

	if (data->old_dentry->d_inode)
		nfs_mark_for_revalidate(data->old_dentry->d_inode);

	dput(data->old_dentry);
	dput(data->new_dentry);
	iput(data->old_dir);
	iput(data->new_dir);
	nfs_sb_deactive(sb);
	put_rpccred(data->cred);
	kfree(data);
}

#if defined(CONFIG_NFS_V4_1)
static void nfs_rename_prepare(struct rpc_task *task, void *calldata)
{
	struct nfs_renamedata *data = calldata;
	struct nfs_server *server = NFS_SERVER(data->old_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_rename_ops = {
	.rpc_call_done = nfs_async_rename_done,
	.rpc_release = nfs_async_rename_release,
#if defined(CONFIG_NFS_V4_1)
	.rpc_call_prepare = nfs_rename_prepare,
#endif /* CONFIG_NFS_V4_1 */
};

/**
 * nfs_async_rename - perform an asynchronous rename operation
 * @old_dir: directory that currently holds the dentry to be renamed
 * @new_dir: target directory for the rename
 * @old_dentry: original dentry to be renamed
 * @new_dentry: dentry to which the old_dentry should be renamed
 *
 * It's expected that valid references to the dentries and inodes are held
 */
static struct rpc_task *
nfs_async_rename(struct inode *old_dir, struct inode *new_dir,
		 struct dentry *old_dentry, struct dentry *new_dentry)
{
	struct nfs_renamedata *data;
	struct rpc_message msg = { };
	struct rpc_task_setup task_setup_data = {
		.rpc_message = &msg,
		.callback_ops = &nfs_rename_ops,
		.workqueue = nfsiod_workqueue,
		.rpc_client = NFS_CLIENT(old_dir),
		.flags = RPC_TASK_ASYNC,
	};

	data = kzalloc(sizeof(*data), GFP_KERNEL);
	if (data == NULL)
		return ERR_PTR(-ENOMEM);
	task_setup_data.callback_data = data;

	data->cred = rpc_lookup_cred();
	if (IS_ERR(data->cred)) {
		struct rpc_task *task = ERR_CAST(data->cred);
		kfree(data);
		return task;
	}

	msg.rpc_argp = &data->args;
	msg.rpc_resp = &data->res;
	msg.rpc_cred = data->cred;

	/* set up nfs_renamedata */
	data->old_dir = old_dir;
	ihold(old_dir);
	data->new_dir = new_dir;
	ihold(new_dir);
	data->old_dentry = dget(old_dentry);
	data->new_dentry = dget(new_dentry);
	nfs_fattr_init(&data->old_fattr);
	nfs_fattr_init(&data->new_fattr);

	/* set up nfs_renameargs */
	data->args.old_dir = NFS_FH(old_dir);
	data->args.old_name = &old_dentry->d_name;
	data->args.new_dir = NFS_FH(new_dir);
	data->args.new_name = &new_dentry->d_name;

	/* set up nfs_renameres */
	data->res.old_fattr = &data->old_fattr;
	data->res.new_fattr = &data->new_fattr;

	nfs_sb_active(old_dir->i_sb);

	NFS_PROTO(data->old_dir)->rename_setup(&msg, old_dir);

	return rpc_run_task(&task_setup_data);
}

/**
 * nfs_sillyrename - Perform a silly-rename of a dentry
 * @dir: inode of directory that contains dentry
 * @dentry: dentry to be sillyrenamed
 *
 * NFSv2/3 is stateless and the server doesn't know when the client is
 * holding a file open. To prevent application problems when a file is
 * unlinked while it's still open, the client performs a "silly-rename".
 * That is, it renames the file to a hidden file in the same directory,
 * and only performs the unlink once the last reference to it is put.
 *
 * The final cleanup is done during dentry_iput.
 */
int
nfs_sillyrename(struct inode *dir, struct dentry *dentry)
{
	static unsigned int sillycounter;
	const int      fileidsize  = sizeof(NFS_FILEID(dentry->d_inode))*2;
	const int      countersize = sizeof(sillycounter)*2;
	const int      slen        = sizeof(".nfs")+fileidsize+countersize-1;
	char           silly[slen+1];
	struct dentry *sdentry;
	struct rpc_task *task;
	int            error = -EIO;

	dfprintk(VFS, "NFS: silly-rename(%s/%s, ct=%d)\n",
		dentry->d_parent->d_name.name, dentry->d_name.name,
		dentry->d_count);
	nfs_inc_stats(dir, NFSIOS_SILLYRENAME);

	/*
	 * We don't allow a dentry to be silly-renamed twice.
	 */
	error = -EBUSY;
	if (dentry->d_flags & DCACHE_NFSFS_RENAMED)
		goto out;

	sprintf(silly, ".nfs%*.*Lx",
		fileidsize, fileidsize,
		(unsigned long long)NFS_FILEID(dentry->d_inode));

	/* Return delegation in anticipation of the rename */
	nfs_inode_return_delegation(dentry->d_inode);

	sdentry = NULL;
	do {
		char *suffix = silly + slen - countersize;

		dput(sdentry);
		sillycounter++;
		sprintf(suffix, "%*.*x", countersize, countersize, sillycounter);

		dfprintk(VFS, "NFS: trying to rename %s to %s\n",
				dentry->d_name.name, silly);

		sdentry = lookup_one_len(silly, dentry->d_parent, slen);
		/*
		 * N.B. Better to return EBUSY here ... it could be
		 * dangerous to delete the file while it's in use.
		 */
		if (IS_ERR(sdentry))
			goto out;
	} while (sdentry->d_inode != NULL); /* need negative lookup */

	/* queue unlink first. Can't do this from rpc_release as it
	 * has to allocate memory
	 */
	error = nfs_async_unlink(dir, dentry);
	if (error)
		goto out_dput;

	/* run the rename task, undo unlink if it fails */
	task = nfs_async_rename(dir, dir, dentry, sdentry);
	if (IS_ERR(task)) {
		error = -EBUSY;
		nfs_cancel_async_unlink(dentry);
		goto out_dput;
	}

	/* wait for the RPC task to complete, unless a SIGKILL intervenes */
	error = rpc_wait_for_completion_task(task);
	if (error == 0)
		error = task->tk_status;
	rpc_put_task(task);
out_dput:
	dput(sdentry);
out:
	return error;
}
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>
779c5179	16	#include <linux/namei.h>
1da177e4	17
ef818a28	18	#include "internal.h"
472cfbd9	19	#include "nfs4_fs.h"
779c5179 JL	20	#include "iostat.h"
779c5179 JL	21	#include "delegation.h"
ef818a28	22
1da177e4	23	struct nfs_unlinkdata {
565277f6	24	struct hlist_node list;
e4eff1a6 TM	25	struct nfs_removeargs args;
	26	struct nfs_removeres res;
	27	struct inode *dir;
1da177e4	28	struct rpc_cred *cred;
d346890b	29	struct nfs_fattr dir_attr;
1da177e4 LT	30	};
1da177e4 LT	31
1da177e4	32	/**
e4eff1a6	33	* nfs_free_unlinkdata - release data from a sillydelete operation.
1da177e4 LT	34	* @data: pointer to unlink structure.
	35	*/
	36	static void
e4eff1a6	37	nfs_free_unlinkdata(struct nfs_unlinkdata *data)
1da177e4	38	{
e4eff1a6 TM	39	iput(data->dir);
	40	put_rpccred(data->cred);
	41	kfree(data->args.name.name);
	42	kfree(data);
1da177e4 LT	43	}
	44
	45	#define NAME_ALLOC_LEN(len) ((len+16) & ~15)
	46	/**
	47	* nfs_copy_dname - copy dentry name to data structure
	48	* @dentry: pointer to dentry
	49	* @data: nfs_unlinkdata
	50	*/
e4eff1a6	51	static int nfs_copy_dname(struct dentry dentry, struct nfs_unlinkdata data)
1da177e4 LT	52	{
	53	char *str;
	54	int len = dentry->d_name.len;
	55
e4eff1a6	56	str = kmemdup(dentry->d_name.name, NAME_ALLOC_LEN(len), GFP_KERNEL);
1da177e4	57	if (!str)
e4eff1a6 TM	58	return -ENOMEM;
	59	data->args.name.len = len;
	60	data->args.name.name = str;
	61	return 0;
1da177e4 LT	62	}
1da177e4 LT	63
565277f6 TM	64	static void nfs_free_dname(struct nfs_unlinkdata *data)
	65	{
	66	kfree(data->args.name.name);
	67	data->args.name.name = NULL;
	68	data->args.name.len = 0;
	69	}
	70
	71	static void nfs_dec_sillycount(struct inode *dir)
	72	{
	73	struct nfs_inode *nfsi = NFS_I(dir);
	74	if (atomic_dec_return(&nfsi->silly_count) == 1)
	75	wake_up(&nfsi->waitqueue);
	76	}
	77
1da177e4 LT	78	/**
	79	* nfs_async_unlink_done - Sillydelete post-processing
	80	* @task: rpc_task of the sillydelete
	81	*
	82	* Do the directory attribute update.
	83	*/
963d8fe5	84	static void nfs_async_unlink_done(struct rpc_task task, void calldata)
1da177e4	85	{
e4eff1a6 TM	86	struct nfs_unlinkdata *data = calldata;
	87	struct inode *dir = data->dir;
	88
	89	if (!NFS_PROTO(dir)->unlink_done(task, dir))
0110ee15	90	nfs_restart_rpc(task, NFS_SERVER(dir)->nfs_client);
1da177e4 LT	91	}
	92
	93	/**
	94	* nfs_async_unlink_release - Release the sillydelete data.
	95	* @task: rpc_task of the sillydelete
	96	*
	97	* We need to call nfs_put_unlinkdata as a 'tk_release' task since the
	98	* rpc_task would be freed too.
	99	*/
963d8fe5	100	static void nfs_async_unlink_release(void *calldata)
1da177e4	101	{
963d8fe5	102	struct nfs_unlinkdata *data = calldata;
744d18db	103	struct super_block *sb = data->dir->i_sb;
565277f6 TM	104
565277f6 TM	105	nfs_dec_sillycount(data->dir);
e4eff1a6	106	nfs_free_unlinkdata(data);
1daef0a8	107	nfs_sb_deactive(sb);
1da177e4 LT	108	}
1da177e4 LT	109
472cfbd9 AA	110	#if defined(CONFIG_NFS_V4_1)
	111	void nfs_unlink_prepare(struct rpc_task task, void calldata)
	112	{
	113	struct nfs_unlinkdata *data = calldata;
	114	struct nfs_server *server = NFS_SERVER(data->dir);
	115
035168ab	116	if (nfs4_setup_sequence(server, &data->args.seq_args,
472cfbd9 AA	117	&data->res.seq_res, 1, task))
	118	return;
	119	rpc_call_start(task);
	120	}
	121	#endif /* CONFIG_NFS_V4_1 */
	122
963d8fe5 TM	123	static const struct rpc_call_ops nfs_unlink_ops = {
	124	.rpc_call_done = nfs_async_unlink_done,
	125	.rpc_release = nfs_async_unlink_release,
472cfbd9 AA	126	#if defined(CONFIG_NFS_V4_1)
	127	.rpc_call_prepare = nfs_unlink_prepare,
	128	#endif /* CONFIG_NFS_V4_1 */
963d8fe5 TM	129	};
963d8fe5 TM	130
565277f6	131	static int nfs_do_call_unlink(struct dentry parent, struct inode dir, struct nfs_unlinkdata *data)
e4eff1a6	132	{
5138fde0 TM	133	struct rpc_message msg = {
	134	.rpc_argp = &data->args,
	135	.rpc_resp = &data->res,
	136	.rpc_cred = data->cred,
	137	};
c970aa85	138	struct rpc_task_setup task_setup_data = {
5138fde0	139	.rpc_message = &msg,
c970aa85 TM	140	.callback_ops = &nfs_unlink_ops,
c970aa85 TM	141	.callback_data = data,
1daef0a8	142	.workqueue = nfsiod_workqueue,
c970aa85 TM	143	.flags = RPC_TASK_ASYNC,
c970aa85 TM	144	};
e4eff1a6	145	struct rpc_task *task;
565277f6 TM	146	struct dentry *alias;
	147
	148	alias = d_lookup(parent, &data->args.name);
	149	if (alias != NULL) {
	150	int ret = 0;
609005c3	151
565277f6 TM	152	/*
	153	* Hey, we raced with lookup... See if we need to transfer
	154	* the sillyrename information to the aliased dentry.
	155	*/
	156	nfs_free_dname(data);
	157	spin_lock(&alias->d_lock);
609005c3 TM	158	if (alias->d_inode != NULL &&
609005c3 TM	159	!(alias->d_flags & DCACHE_NFSFS_RENAMED)) {
565277f6	160	alias->d_fsdata = data;
fccca7fc	161	alias->d_flags \|= DCACHE_NFSFS_RENAMED;
565277f6 TM	162	ret = 1;
	163	}
	164	spin_unlock(&alias->d_lock);
	165	nfs_dec_sillycount(dir);
	166	dput(alias);
	167	return ret;
	168	}
	169	data->dir = igrab(dir);
	170	if (!data->dir) {
	171	nfs_dec_sillycount(dir);
	172	return 0;
	173	}
1daef0a8	174	nfs_sb_active(dir->i_sb);
565277f6	175	data->args.fh = NFS_FH(dir);
d346890b	176	nfs_fattr_init(data->res.dir_attr);
565277f6	177
5138fde0	178	NFS_PROTO(dir)->unlink_setup(&msg, dir);
c970aa85	179
5138fde0	180	task_setup_data.rpc_client = NFS_CLIENT(dir);
c970aa85	181	task = rpc_run_task(&task_setup_data);
565277f6 TM	182	if (!IS_ERR(task))
	183	rpc_put_task(task);
	184	return 1;
	185	}
	186
	187	static int nfs_call_unlink(struct dentry dentry, struct nfs_unlinkdata data)
	188	{
e4eff1a6 TM	189	struct dentry *parent;
e4eff1a6 TM	190	struct inode *dir;
565277f6	191	int ret = 0;
e4eff1a6	192
e4eff1a6 TM	193
	194	parent = dget_parent(dentry);
	195	if (parent == NULL)
	196	goto out_free;
565277f6	197	dir = parent->d_inode;
55b70a03	198	if (nfs_copy_dname(dentry, data) != 0)
565277f6 TM	199	goto out_dput;
	200	/* Non-exclusive lock protects against concurrent lookup() calls */
	201	spin_lock(&dir->i_lock);
	202	if (atomic_inc_not_zero(&NFS_I(dir)->silly_count) == 0) {
	203	/* Deferred delete */
	204	hlist_add_head(&data->list, &NFS_I(dir)->silly_list);
	205	spin_unlock(&dir->i_lock);
	206	ret = 1;
	207	goto out_dput;
	208	}
	209	spin_unlock(&dir->i_lock);
	210	ret = nfs_do_call_unlink(parent, dir, data);
	211	out_dput:
e4eff1a6	212	dput(parent);
565277f6 TM	213	out_free:
	214	return ret;
	215	}
e4eff1a6	216
565277f6 TM	217	void nfs_block_sillyrename(struct dentry *dentry)
	218	{
	219	struct nfs_inode *nfsi = NFS_I(dentry->d_inode);
e4eff1a6	220
565277f6 TM	221	wait_event(nfsi->waitqueue, atomic_cmpxchg(&nfsi->silly_count, 1, 0) == 1);
	222	}
	223
	224	void nfs_unblock_sillyrename(struct dentry *dentry)
	225	{
	226	struct inode *dir = dentry->d_inode;
	227	struct nfs_inode *nfsi = NFS_I(dir);
	228	struct nfs_unlinkdata *data;
	229
	230	atomic_inc(&nfsi->silly_count);
	231	spin_lock(&dir->i_lock);
	232	while (!hlist_empty(&nfsi->silly_list)) {
	233	if (!atomic_inc_not_zero(&nfsi->silly_count))
	234	break;
	235	data = hlist_entry(nfsi->silly_list.first, struct nfs_unlinkdata, list);
	236	hlist_del(&data->list);
	237	spin_unlock(&dir->i_lock);
	238	if (nfs_do_call_unlink(dentry, dir, data) == 0)
	239	nfs_free_unlinkdata(data);
	240	spin_lock(&dir->i_lock);
	241	}
	242	spin_unlock(&dir->i_lock);
e4eff1a6 TM	243	}
e4eff1a6 TM	244
1da177e4 LT	245	/**
1da177e4 LT	246	* nfs_async_unlink - asynchronous unlinking of a file
e4eff1a6	247	* @dir: parent directory of dentry
1da177e4 LT	248	* @dentry: dentry to unlink
1da177e4 LT	249	*/
779c5179	250	static int
e4eff1a6	251	nfs_async_unlink(struct inode dir, struct dentry dentry)
1da177e4	252	{
e4eff1a6 TM	253	struct nfs_unlinkdata *data;
e4eff1a6 TM	254	int status = -ENOMEM;
1da177e4	255
bd647545	256	data = kzalloc(sizeof(*data), GFP_KERNEL);
e4eff1a6	257	if (data == NULL)
1da177e4	258	goto out;
1da177e4	259
98a8e323	260	data->cred = rpc_lookup_cred();
1da177e4 LT	261	if (IS_ERR(data->cred)) {
	262	status = PTR_ERR(data->cred);
	263	goto out_free;
	264	}
d346890b	265	data->res.dir_attr = &data->dir_attr;
1da177e4	266
e4eff1a6	267	status = -EBUSY;
1da177e4	268	spin_lock(&dentry->d_lock);
e4eff1a6 TM	269	if (dentry->d_flags & DCACHE_NFSFS_RENAMED)
e4eff1a6 TM	270	goto out_unlock;
1da177e4	271	dentry->d_flags \|= DCACHE_NFSFS_RENAMED;
e4eff1a6	272	dentry->d_fsdata = data;
1da177e4	273	spin_unlock(&dentry->d_lock);
e4eff1a6 TM	274	return 0;
	275	out_unlock:
	276	spin_unlock(&dentry->d_lock);
	277	put_rpccred(data->cred);
1da177e4 LT	278	out_free:
1da177e4 LT	279	kfree(data);
e4eff1a6	280	out:
1da177e4 LT	281	return status;
	282	}
	283
	284	/**
	285	* nfs_complete_unlink - Initialize completion of the sillydelete
	286	* @dentry: dentry to delete
e4eff1a6	287	* @inode: inode
1da177e4 LT	288	*
	289	* Since we're most likely to be called by dentry_iput(), we
	290	* only use the dentry to find the sillydelete. We then copy the name
	291	* into the qstr.
	292	*/
	293	void
e4eff1a6	294	nfs_complete_unlink(struct dentry dentry, struct inode inode)
1da177e4	295	{
e4eff1a6	296	struct nfs_unlinkdata *data = NULL;
1da177e4	297
1da177e4	298	spin_lock(&dentry->d_lock);
e4eff1a6 TM	299	if (dentry->d_flags & DCACHE_NFSFS_RENAMED) {
	300	dentry->d_flags &= ~DCACHE_NFSFS_RENAMED;
	301	data = dentry->d_fsdata;
	302	}
1da177e4	303	spin_unlock(&dentry->d_lock);
e4eff1a6 TM	304
	305	if (data != NULL && (NFS_STALE(inode) \|\| !nfs_call_unlink(dentry, data)))
	306	nfs_free_unlinkdata(data);
1da177e4	307	}
779c5179	308
d3d4152a JL	309	/* Cancel a queued async unlink. Called when a sillyrename run fails. */
	310	static void
	311	nfs_cancel_async_unlink(struct dentry *dentry)
	312	{
	313	spin_lock(&dentry->d_lock);
	314	if (dentry->d_flags & DCACHE_NFSFS_RENAMED) {
	315	struct nfs_unlinkdata *data = dentry->d_fsdata;
	316
	317	dentry->d_flags &= ~DCACHE_NFSFS_RENAMED;
	318	spin_unlock(&dentry->d_lock);
	319	nfs_free_unlinkdata(data);
	320	return;
	321	}
	322	spin_unlock(&dentry->d_lock);
	323	}
	324
	325	struct nfs_renamedata {
	326	struct nfs_renameargs args;
	327	struct nfs_renameres res;
	328	struct rpc_cred *cred;
	329	struct inode *old_dir;
	330	struct dentry *old_dentry;
	331	struct nfs_fattr old_fattr;
	332	struct inode *new_dir;
	333	struct dentry *new_dentry;
	334	struct nfs_fattr new_fattr;
	335	};
	336
	337	/**
	338	* nfs_async_rename_done - Sillyrename post-processing
	339	* @task: rpc_task of the sillyrename
	340	* @calldata: nfs_renamedata for the sillyrename
	341	*
	342	* Do the directory attribute updates and the d_move
	343	*/
	344	static void nfs_async_rename_done(struct rpc_task task, void calldata)
	345	{
	346	struct nfs_renamedata *data = calldata;
	347	struct inode *old_dir = data->old_dir;
	348	struct inode *new_dir = data->new_dir;
	349
	350	if (!NFS_PROTO(old_dir)->rename_done(task, old_dir, new_dir)) {
	351	nfs_restart_rpc(task, NFS_SERVER(old_dir)->nfs_client);
	352	return;
	353	}
	354
	355	if (task->tk_status != 0) {
	356	nfs_cancel_async_unlink(data->old_dentry);
	357	return;
	358	}
	359
	360	nfs_set_verifier(data->old_dentry, nfs_save_change_attribute(old_dir));
	361	d_move(data->old_dentry, data->new_dentry);
	362	}
	363
	364	/**
	365	* nfs_async_rename_release - Release the sillyrename data.
	366	* @calldata: the struct nfs_renamedata to be released
	367	*/
	368	static void nfs_async_rename_release(void *calldata)
	369	{
	370	struct nfs_renamedata *data = calldata;
	371	struct super_block *sb = data->old_dir->i_sb;
	372
373	if (data->old_dentry->d_inode)
374	nfs_mark_for_revalidate(data->old_dentry->d_inode);
375
376	dput(data->old_dentry);
377	dput(data->new_dentry);
378	iput(data->old_dir);
379	iput(data->new_dir);
380	nfs_sb_deactive(sb);
381	put_rpccred(data->cred);
382	kfree(data);
383	}
384
385	#if defined(CONFIG_NFS_V4_1)
386	static void nfs_rename_prepare(struct rpc_task task, void calldata)
387	{
388	struct nfs_renamedata *data = calldata;
389	struct nfs_server *server = NFS_SERVER(data->old_dir);
390
391	if (nfs4_setup_sequence(server, &data->args.seq_args,
392	&data->res.seq_res, 1, task))
393	return;
394	rpc_call_start(task);
395	}
396	#endif /* CONFIG_NFS_V4_1 */
397
398	static const struct rpc_call_ops nfs_rename_ops = {
399	.rpc_call_done = nfs_async_rename_done,
400	.rpc_release = nfs_async_rename_release,
401	#if defined(CONFIG_NFS_V4_1)
402	.rpc_call_prepare = nfs_rename_prepare,
403	#endif /* CONFIG_NFS_V4_1 */
404	};
405
406	/**
407	* nfs_async_rename - perform an asynchronous rename operation
408	* @old_dir: directory that currently holds the dentry to be renamed
409	* @new_dir: target directory for the rename
410	* @old_dentry: original dentry to be renamed
411	* @new_dentry: dentry to which the old_dentry should be renamed
412	*
413	* It's expected that valid references to the dentries and inodes are held
414	*/
415	static struct rpc_task *
416	nfs_async_rename(struct inode old_dir, struct inode new_dir,
417	struct dentry old_dentry, struct dentry new_dentry)
418	{
419	struct nfs_renamedata *data;
420	struct rpc_message msg = { };
421	struct rpc_task_setup task_setup_data = {
422	.rpc_message = &msg,
423	.callback_ops = &nfs_rename_ops,
424	.workqueue = nfsiod_workqueue,
425	.rpc_client = NFS_CLIENT(old_dir),
426	.flags = RPC_TASK_ASYNC,
427	};
d3d4152a	428
dfb4f309	429	data = kzalloc(sizeof(*data), GFP_KERNEL);
d3d4152a JL	430	if (data == NULL)
d3d4152a JL	431	return ERR_PTR(-ENOMEM);
1174dd1f	432	task_setup_data.callback_data = data;
d3d4152a JL	433
	434	data->cred = rpc_lookup_cred();
	435	if (IS_ERR(data->cred)) {
f7732d65	436	struct rpc_task *task = ERR_CAST(data->cred);
d3d4152a JL	437	kfree(data);
	438	return task;
	439	}
	440
	441	msg.rpc_argp = &data->args;
	442	msg.rpc_resp = &data->res;
	443	msg.rpc_cred = data->cred;
	444
	445	/* set up nfs_renamedata */
	446	data->old_dir = old_dir;
a4118ee1	447	ihold(old_dir);
d3d4152a	448	data->new_dir = new_dir;
a4118ee1	449	ihold(new_dir);
d3d4152a JL	450	data->old_dentry = dget(old_dentry);
	451	data->new_dentry = dget(new_dentry);
	452	nfs_fattr_init(&data->old_fattr);
	453	nfs_fattr_init(&data->new_fattr);
	454
	455	/* set up nfs_renameargs */
	456	data->args.old_dir = NFS_FH(old_dir);
	457	data->args.old_name = &old_dentry->d_name;
	458	data->args.new_dir = NFS_FH(new_dir);
	459	data->args.new_name = &new_dentry->d_name;
	460
	461	/* set up nfs_renameres */
	462	data->res.old_fattr = &data->old_fattr;
	463	data->res.new_fattr = &data->new_fattr;
	464
	465	nfs_sb_active(old_dir->i_sb);
	466
	467	NFS_PROTO(data->old_dir)->rename_setup(&msg, old_dir);
	468
f7732d65	469	return rpc_run_task(&task_setup_data);
d3d4152a JL	470	}
d3d4152a JL	471
779c5179 JL	472	/**
	473	* nfs_sillyrename - Perform a silly-rename of a dentry
	474	* @dir: inode of directory that contains dentry
	475	* @dentry: dentry to be sillyrenamed
	476	*
	477	* NFSv2/3 is stateless and the server doesn't know when the client is
	478	* holding a file open. To prevent application problems when a file is
	479	* unlinked while it's still open, the client performs a "silly-rename".
	480	* That is, it renames the file to a hidden file in the same directory,
	481	* and only performs the unlink once the last reference to it is put.
	482	*
	483	* The final cleanup is done during dentry_iput.
	484	*/
	485	int
	486	nfs_sillyrename(struct inode dir, struct dentry dentry)
	487	{
	488	static unsigned int sillycounter;
	489	const int fileidsize = sizeof(NFS_FILEID(dentry->d_inode))*2;
	490	const int countersize = sizeof(sillycounter)*2;
	491	const int slen = sizeof(".nfs")+fileidsize+countersize-1;
	492	char silly[slen+1];
779c5179	493	struct dentry *sdentry;
d3d4152a	494	struct rpc_task *task;
779c5179 JL	495	int error = -EIO;
	496
	497	dfprintk(VFS, "NFS: silly-rename(%s/%s, ct=%d)\n",
	498	dentry->d_parent->d_name.name, dentry->d_name.name,
b7ab39f6	499	dentry->d_count);
779c5179 JL	500	nfs_inc_stats(dir, NFSIOS_SILLYRENAME);
	501
	502	/*
	503	* We don't allow a dentry to be silly-renamed twice.
	504	*/
	505	error = -EBUSY;
	506	if (dentry->d_flags & DCACHE_NFSFS_RENAMED)
	507	goto out;
	508
	509	sprintf(silly, ".nfs%.Lx",
	510	fileidsize, fileidsize,
	511	(unsigned long long)NFS_FILEID(dentry->d_inode));
	512
	513	/* Return delegation in anticipation of the rename */
	514	nfs_inode_return_delegation(dentry->d_inode);
	515
	516	sdentry = NULL;
	517	do {
	518	char *suffix = silly + slen - countersize;
	519
	520	dput(sdentry);
	521	sillycounter++;
	522	sprintf(suffix, "%.x", countersize, countersize, sillycounter);
	523
	524	dfprintk(VFS, "NFS: trying to rename %s to %s\n",
	525	dentry->d_name.name, silly);
	526
	527	sdentry = lookup_one_len(silly, dentry->d_parent, slen);
	528	/*
	529	* N.B. Better to return EBUSY here ... it could be
	530	* dangerous to delete the file while it's in use.
	531	*/
	532	if (IS_ERR(sdentry))
	533	goto out;
	534	} while (sdentry->d_inode != NULL); /* need negative lookup */
	535
d3d4152a JL	536	/* queue unlink first. Can't do this from rpc_release as it
	537	* has to allocate memory
	538	*/
	539	error = nfs_async_unlink(dir, dentry);
	540	if (error)
	541	goto out_dput;
	542
	543	/* run the rename task, undo unlink if it fails */
	544	task = nfs_async_rename(dir, dir, dentry, sdentry);
	545	if (IS_ERR(task)) {
	546	error = -EBUSY;
	547	nfs_cancel_async_unlink(dentry);
	548	goto out_dput;
779c5179	549	}
d3d4152a JL	550
	551	/* wait for the RPC task to complete, unless a SIGKILL intervenes */
	552	error = rpc_wait_for_completion_task(task);
	553	if (error == 0)
	554	error = task->tk_status;
	555	rpc_put_task(task);
	556	out_dput:
779c5179 JL	557	dput(sdentry);
	558	out:
	559	return error;
	560	}