[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"

/**
 * 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_prepare(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 void nfs_unlink_prepare(struct rpc_task *task, void *calldata)
{
	struct nfs_unlinkdata *data = calldata;
	NFS_PROTO(data->dir)->unlink_rpc_prepare(task, data);
}

static const struct rpc_call_ops nfs_unlink_ops = {
	.rpc_call_done = nfs_async_unlink_done,
	.rpc_release = nfs_async_unlink_release,
	.rpc_call_prepare = nfs_unlink_prepare,
};

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;
		void *devname_garbage = NULL;

		/*
		 * Hey, we raced with lookup... See if we need to transfer
		 * the sillyrename information to the aliased dentry.
		 */
		nfs_free_dname(data);
		ret = nfs_copy_dname(alias, data);
		spin_lock(&alias->d_lock);
		if (ret == 0 && alias->d_inode != NULL &&
		    !(alias->d_flags & DCACHE_NFSFS_RENAMED)) {
			devname_garbage = alias->d_fsdata;
			alias->d_fsdata = data;
			alias->d_flags |= DCACHE_NFSFS_RENAMED;
			ret = 1;
		} else
			ret = 0;
		spin_unlock(&alias->d_lock);
		nfs_dec_sillycount(dir);
		dput(alias);
		/*
		 * If we'd displaced old cached devname, free it.  At that
		 * point dentry is definitely not a root, so we won't need
		 * that anymore.
		 */
		kfree(devname_garbage);
		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_async(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;
	/* 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;
	void *devname_garbage = NULL;

	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;
	devname_garbage = dentry->d_fsdata;
	dentry->d_fsdata = data;
	spin_unlock(&dentry->d_lock);
	/*
	 * If we'd displaced old cached devname, free it.  At that
	 * point dentry is definitely not a root, so we won't need
	 * that anymore.
	 */
	if (devname_garbage)
		kfree(devname_garbage);
	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;
		dentry->d_fsdata = NULL;
	}
	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;
		dentry->d_fsdata = NULL;
		spin_unlock(&dentry->d_lock);
		nfs_free_unlinkdata(data);
		return;
	}
	spin_unlock(&dentry->d_lock);
}

/**
 * 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;
	struct dentry *old_dentry = data->old_dentry;
	struct dentry *new_dentry = data->new_dentry;

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

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

	d_drop(old_dentry);
	d_drop(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);
}

static void nfs_rename_prepare(struct rpc_task *task, void *calldata)
{
	struct nfs_renamedata *data = calldata;
	NFS_PROTO(data->old_dir)->rename_rpc_prepare(task, data);
}

static const struct rpc_call_ops nfs_rename_ops = {
	.rpc_call_done = nfs_async_rename_done,
	.rpc_release = nfs_async_rename_release,
	.rpc_call_prepare = nfs_rename_prepare,
};

/**
 * 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.
 *
 * (Note: NFSv4 is stateful, and has opens, so in theory an NFSv4 server
 * could take responsibility for keeping open files referenced.  The server
 * would also need to ensure that opened-but-deleted files were kept over
 * reboots.  However, we may not assume a server does so.  (RFC 5661
 * does provide an OPEN4_RESULT_PRESERVE_UNLINKED flag that a server can
 * use to advertise that it does this; some day we may take advantage of
 * it.))
 */
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_PROTO(dentry->d_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;

	/* populate unlinkdata with the right dname */
	error = nfs_copy_dname(sdentry,
				(struct nfs_unlinkdata *)dentry->d_fsdata);
	if (error) {
		nfs_cancel_async_unlink(dentry);
		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	/**
e4eff1a6	24	* nfs_free_unlinkdata - release data from a sillydelete operation.
1da177e4 LT	25	* @data: pointer to unlink structure.
	26	*/
	27	static void
e4eff1a6	28	nfs_free_unlinkdata(struct nfs_unlinkdata *data)
1da177e4	29	{
e4eff1a6 TM	30	iput(data->dir);
	31	put_rpccred(data->cred);
	32	kfree(data->args.name.name);
	33	kfree(data);
1da177e4 LT	34	}
	35
	36	#define NAME_ALLOC_LEN(len) ((len+16) & ~15)
	37	/**
	38	* nfs_copy_dname - copy dentry name to data structure
	39	* @dentry: pointer to dentry
	40	* @data: nfs_unlinkdata
	41	*/
e4eff1a6	42	static int nfs_copy_dname(struct dentry dentry, struct nfs_unlinkdata data)
1da177e4 LT	43	{
	44	char *str;
	45	int len = dentry->d_name.len;
	46
e4eff1a6	47	str = kmemdup(dentry->d_name.name, NAME_ALLOC_LEN(len), GFP_KERNEL);
1da177e4	48	if (!str)
e4eff1a6 TM	49	return -ENOMEM;
	50	data->args.name.len = len;
	51	data->args.name.name = str;
	52	return 0;
1da177e4 LT	53	}
1da177e4 LT	54
565277f6 TM	55	static void nfs_free_dname(struct nfs_unlinkdata *data)
	56	{
	57	kfree(data->args.name.name);
	58	data->args.name.name = NULL;
	59	data->args.name.len = 0;
	60	}
	61
	62	static void nfs_dec_sillycount(struct inode *dir)
	63	{
	64	struct nfs_inode *nfsi = NFS_I(dir);
	65	if (atomic_dec_return(&nfsi->silly_count) == 1)
	66	wake_up(&nfsi->waitqueue);
	67	}
	68
1da177e4 LT	69	/**
	70	* nfs_async_unlink_done - Sillydelete post-processing
	71	* @task: rpc_task of the sillydelete
	72	*
	73	* Do the directory attribute update.
	74	*/
963d8fe5	75	static void nfs_async_unlink_done(struct rpc_task task, void calldata)
1da177e4	76	{
e4eff1a6 TM	77	struct nfs_unlinkdata *data = calldata;
	78	struct inode *dir = data->dir;
	79
	80	if (!NFS_PROTO(dir)->unlink_done(task, dir))
d00c5d43	81	rpc_restart_call_prepare(task);
1da177e4 LT	82	}
	83
	84	/**
	85	* nfs_async_unlink_release - Release the sillydelete data.
	86	* @task: rpc_task of the sillydelete
	87	*
	88	* We need to call nfs_put_unlinkdata as a 'tk_release' task since the
	89	* rpc_task would be freed too.
	90	*/
963d8fe5	91	static void nfs_async_unlink_release(void *calldata)
1da177e4	92	{
963d8fe5	93	struct nfs_unlinkdata *data = calldata;
744d18db	94	struct super_block *sb = data->dir->i_sb;
565277f6 TM	95
565277f6 TM	96	nfs_dec_sillycount(data->dir);
e4eff1a6	97	nfs_free_unlinkdata(data);
1daef0a8	98	nfs_sb_deactive(sb);
1da177e4 LT	99	}
1da177e4 LT	100
17280175	101	static void nfs_unlink_prepare(struct rpc_task task, void calldata)
472cfbd9 AA	102	{
472cfbd9 AA	103	struct nfs_unlinkdata *data = calldata;
34e137cc	104	NFS_PROTO(data->dir)->unlink_rpc_prepare(task, data);
472cfbd9	105	}
472cfbd9	106
963d8fe5 TM	107	static const struct rpc_call_ops nfs_unlink_ops = {
	108	.rpc_call_done = nfs_async_unlink_done,
	109	.rpc_release = nfs_async_unlink_release,
472cfbd9	110	.rpc_call_prepare = nfs_unlink_prepare,
963d8fe5 TM	111	};
963d8fe5 TM	112
565277f6	113	static int nfs_do_call_unlink(struct dentry parent, struct inode dir, struct nfs_unlinkdata *data)
e4eff1a6	114	{
5138fde0 TM	115	struct rpc_message msg = {
	116	.rpc_argp = &data->args,
	117	.rpc_resp = &data->res,
	118	.rpc_cred = data->cred,
	119	};
c970aa85	120	struct rpc_task_setup task_setup_data = {
5138fde0	121	.rpc_message = &msg,
c970aa85 TM	122	.callback_ops = &nfs_unlink_ops,
c970aa85 TM	123	.callback_data = data,
1daef0a8	124	.workqueue = nfsiod_workqueue,
c970aa85 TM	125	.flags = RPC_TASK_ASYNC,
c970aa85 TM	126	};
e4eff1a6	127	struct rpc_task *task;
565277f6 TM	128	struct dentry *alias;
	129
	130	alias = d_lookup(parent, &data->args.name);
	131	if (alias != NULL) {
73ca1001	132	int ret;
b1942c5f	133	void *devname_garbage = NULL;
609005c3	134
565277f6 TM	135	/*
	136	* Hey, we raced with lookup... See if we need to transfer
	137	* the sillyrename information to the aliased dentry.
	138	*/
	139	nfs_free_dname(data);
73ca1001	140	ret = nfs_copy_dname(alias, data);
565277f6	141	spin_lock(&alias->d_lock);
73ca1001	142	if (ret == 0 && alias->d_inode != NULL &&
609005c3	143	!(alias->d_flags & DCACHE_NFSFS_RENAMED)) {
b1942c5f	144	devname_garbage = alias->d_fsdata;
565277f6	145	alias->d_fsdata = data;
fccca7fc	146	alias->d_flags \|= DCACHE_NFSFS_RENAMED;
565277f6	147	ret = 1;
73ca1001 JL	148	} else
73ca1001 JL	149	ret = 0;
565277f6 TM	150	spin_unlock(&alias->d_lock);
	151	nfs_dec_sillycount(dir);
	152	dput(alias);
b1942c5f AV	153	/*
	154	* If we'd displaced old cached devname, free it. At that
	155	* point dentry is definitely not a root, so we won't need
	156	* that anymore.
	157	*/
73ca1001	158	kfree(devname_garbage);
565277f6 TM	159	return ret;
	160	}
	161	data->dir = igrab(dir);
	162	if (!data->dir) {
	163	nfs_dec_sillycount(dir);
	164	return 0;
	165	}
1daef0a8	166	nfs_sb_active(dir->i_sb);
565277f6	167	data->args.fh = NFS_FH(dir);
d346890b	168	nfs_fattr_init(data->res.dir_attr);
565277f6	169
5138fde0	170	NFS_PROTO(dir)->unlink_setup(&msg, dir);
c970aa85	171
5138fde0	172	task_setup_data.rpc_client = NFS_CLIENT(dir);
c970aa85	173	task = rpc_run_task(&task_setup_data);
565277f6	174	if (!IS_ERR(task))
bf294b41	175	rpc_put_task_async(task);
565277f6 TM	176	return 1;
	177	}
	178
	179	static int nfs_call_unlink(struct dentry dentry, struct nfs_unlinkdata data)
	180	{
e4eff1a6 TM	181	struct dentry *parent;
e4eff1a6 TM	182	struct inode *dir;
565277f6	183	int ret = 0;
e4eff1a6	184
e4eff1a6 TM	185
	186	parent = dget_parent(dentry);
	187	if (parent == NULL)
	188	goto out_free;
565277f6	189	dir = parent->d_inode;
565277f6 TM	190	/* Non-exclusive lock protects against concurrent lookup() calls */
	191	spin_lock(&dir->i_lock);
	192	if (atomic_inc_not_zero(&NFS_I(dir)->silly_count) == 0) {
	193	/* Deferred delete */
	194	hlist_add_head(&data->list, &NFS_I(dir)->silly_list);
	195	spin_unlock(&dir->i_lock);
	196	ret = 1;
	197	goto out_dput;
	198	}
	199	spin_unlock(&dir->i_lock);
	200	ret = nfs_do_call_unlink(parent, dir, data);
	201	out_dput:
e4eff1a6	202	dput(parent);
565277f6 TM	203	out_free:
	204	return ret;
	205	}
e4eff1a6	206
565277f6 TM	207	void nfs_block_sillyrename(struct dentry *dentry)
	208	{
	209	struct nfs_inode *nfsi = NFS_I(dentry->d_inode);
e4eff1a6	210
565277f6 TM	211	wait_event(nfsi->waitqueue, atomic_cmpxchg(&nfsi->silly_count, 1, 0) == 1);
	212	}
	213
	214	void nfs_unblock_sillyrename(struct dentry *dentry)
	215	{
	216	struct inode *dir = dentry->d_inode;
	217	struct nfs_inode *nfsi = NFS_I(dir);
	218	struct nfs_unlinkdata *data;
	219
	220	atomic_inc(&nfsi->silly_count);
	221	spin_lock(&dir->i_lock);
	222	while (!hlist_empty(&nfsi->silly_list)) {
	223	if (!atomic_inc_not_zero(&nfsi->silly_count))
	224	break;
	225	data = hlist_entry(nfsi->silly_list.first, struct nfs_unlinkdata, list);
	226	hlist_del(&data->list);
	227	spin_unlock(&dir->i_lock);
	228	if (nfs_do_call_unlink(dentry, dir, data) == 0)
	229	nfs_free_unlinkdata(data);
	230	spin_lock(&dir->i_lock);
	231	}
	232	spin_unlock(&dir->i_lock);
e4eff1a6 TM	233	}
e4eff1a6 TM	234
1da177e4 LT	235	/**
1da177e4 LT	236	* nfs_async_unlink - asynchronous unlinking of a file
e4eff1a6	237	* @dir: parent directory of dentry
1da177e4 LT	238	* @dentry: dentry to unlink
1da177e4 LT	239	*/
779c5179	240	static int
e4eff1a6	241	nfs_async_unlink(struct inode dir, struct dentry dentry)
1da177e4	242	{
e4eff1a6 TM	243	struct nfs_unlinkdata *data;
e4eff1a6 TM	244	int status = -ENOMEM;
b1942c5f	245	void *devname_garbage = NULL;
1da177e4	246
bd647545	247	data = kzalloc(sizeof(*data), GFP_KERNEL);
e4eff1a6	248	if (data == NULL)
1da177e4	249	goto out;
1da177e4	250
98a8e323	251	data->cred = rpc_lookup_cred();
1da177e4 LT	252	if (IS_ERR(data->cred)) {
	253	status = PTR_ERR(data->cred);
	254	goto out_free;
	255	}
d346890b	256	data->res.dir_attr = &data->dir_attr;
1da177e4	257
e4eff1a6	258	status = -EBUSY;
1da177e4	259	spin_lock(&dentry->d_lock);
e4eff1a6 TM	260	if (dentry->d_flags & DCACHE_NFSFS_RENAMED)
e4eff1a6 TM	261	goto out_unlock;
1da177e4	262	dentry->d_flags \|= DCACHE_NFSFS_RENAMED;
b1942c5f	263	devname_garbage = dentry->d_fsdata;
e4eff1a6	264	dentry->d_fsdata = data;
1da177e4	265	spin_unlock(&dentry->d_lock);
b1942c5f AV	266	/*
	267	* If we'd displaced old cached devname, free it. At that
	268	* point dentry is definitely not a root, so we won't need
	269	* that anymore.
	270	*/
	271	if (devname_garbage)
	272	kfree(devname_garbage);
e4eff1a6 TM	273	return 0;
	274	out_unlock:
	275	spin_unlock(&dentry->d_lock);
	276	put_rpccred(data->cred);
1da177e4 LT	277	out_free:
1da177e4 LT	278	kfree(data);
e4eff1a6	279	out:
1da177e4 LT	280	return status;
	281	}
	282
	283	/**
	284	* nfs_complete_unlink - Initialize completion of the sillydelete
	285	* @dentry: dentry to delete
e4eff1a6	286	* @inode: inode
1da177e4 LT	287	*
	288	* Since we're most likely to be called by dentry_iput(), we
	289	* only use the dentry to find the sillydelete. We then copy the name
	290	* into the qstr.
	291	*/
	292	void
e4eff1a6	293	nfs_complete_unlink(struct dentry dentry, struct inode inode)
1da177e4	294	{
e4eff1a6	295	struct nfs_unlinkdata *data = NULL;
1da177e4	296
1da177e4	297	spin_lock(&dentry->d_lock);
e4eff1a6 TM	298	if (dentry->d_flags & DCACHE_NFSFS_RENAMED) {
	299	dentry->d_flags &= ~DCACHE_NFSFS_RENAMED;
	300	data = dentry->d_fsdata;
b1942c5f	301	dentry->d_fsdata = NULL;
e4eff1a6	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;
b1942c5f	318	dentry->d_fsdata = NULL;
d3d4152a JL	319	spin_unlock(&dentry->d_lock);
	320	nfs_free_unlinkdata(data);
	321	return;
	322	}
	323	spin_unlock(&dentry->d_lock);
	324	}
	325
d3d4152a JL	326	/**
	327	* nfs_async_rename_done - Sillyrename post-processing
	328	* @task: rpc_task of the sillyrename
	329	* @calldata: nfs_renamedata for the sillyrename
	330	*
	331	* Do the directory attribute updates and the d_move
	332	*/
	333	static void nfs_async_rename_done(struct rpc_task task, void calldata)
	334	{
	335	struct nfs_renamedata *data = calldata;
	336	struct inode *old_dir = data->old_dir;
	337	struct inode *new_dir = data->new_dir;
73ca1001 JL	338	struct dentry *old_dentry = data->old_dentry;
73ca1001 JL	339	struct dentry *new_dentry = data->new_dentry;
d3d4152a JL	340
d3d4152a JL	341	if (!NFS_PROTO(old_dir)->rename_done(task, old_dir, new_dir)) {
d00c5d43	342	rpc_restart_call_prepare(task);
d3d4152a JL	343	return;
	344	}
	345
	346	if (task->tk_status != 0) {
73ca1001	347	nfs_cancel_async_unlink(old_dentry);
d3d4152a JL	348	return;
	349	}
	350
73ca1001 JL	351	d_drop(old_dentry);
73ca1001 JL	352	d_drop(new_dentry);
d3d4152a JL	353	}
	354
	355	/**
	356	* nfs_async_rename_release - Release the sillyrename data.
	357	* @calldata: the struct nfs_renamedata to be released
	358	*/
	359	static void nfs_async_rename_release(void *calldata)
	360	{
	361	struct nfs_renamedata *data = calldata;
	362	struct super_block *sb = data->old_dir->i_sb;
	363
	364	if (data->old_dentry->d_inode)
	365	nfs_mark_for_revalidate(data->old_dentry->d_inode);
	366
	367	dput(data->old_dentry);
	368	dput(data->new_dentry);
	369	iput(data->old_dir);
	370	iput(data->new_dir);
	371	nfs_sb_deactive(sb);
	372	put_rpccred(data->cred);
	373	kfree(data);
	374	}
	375
d3d4152a JL	376	static void nfs_rename_prepare(struct rpc_task task, void calldata)
	377	{
	378	struct nfs_renamedata *data = calldata;
c6bfa1a1	379	NFS_PROTO(data->old_dir)->rename_rpc_prepare(task, data);
d3d4152a	380	}
d3d4152a JL	381
	382	static const struct rpc_call_ops nfs_rename_ops = {
	383	.rpc_call_done = nfs_async_rename_done,
	384	.rpc_release = nfs_async_rename_release,
d3d4152a	385	.rpc_call_prepare = nfs_rename_prepare,
d3d4152a JL	386	};
	387
	388	/**
	389	* nfs_async_rename - perform an asynchronous rename operation
	390	* @old_dir: directory that currently holds the dentry to be renamed
	391	* @new_dir: target directory for the rename
	392	* @old_dentry: original dentry to be renamed
	393	* @new_dentry: dentry to which the old_dentry should be renamed
	394	*
	395	* It's expected that valid references to the dentries and inodes are held
	396	*/
	397	static struct rpc_task *
	398	nfs_async_rename(struct inode old_dir, struct inode new_dir,
	399	struct dentry old_dentry, struct dentry new_dentry)
	400	{
	401	struct nfs_renamedata *data;
	402	struct rpc_message msg = { };
	403	struct rpc_task_setup task_setup_data = {
	404	.rpc_message = &msg,
	405	.callback_ops = &nfs_rename_ops,
	406	.workqueue = nfsiod_workqueue,
	407	.rpc_client = NFS_CLIENT(old_dir),
	408	.flags = RPC_TASK_ASYNC,
	409	};
d3d4152a	410
dfb4f309	411	data = kzalloc(sizeof(*data), GFP_KERNEL);
d3d4152a JL	412	if (data == NULL)
d3d4152a JL	413	return ERR_PTR(-ENOMEM);
1174dd1f	414	task_setup_data.callback_data = data;
d3d4152a JL	415
	416	data->cred = rpc_lookup_cred();
	417	if (IS_ERR(data->cred)) {
f7732d65	418	struct rpc_task *task = ERR_CAST(data->cred);
d3d4152a JL	419	kfree(data);
	420	return task;
	421	}
	422
	423	msg.rpc_argp = &data->args;
	424	msg.rpc_resp = &data->res;
	425	msg.rpc_cred = data->cred;
	426
	427	/* set up nfs_renamedata */
	428	data->old_dir = old_dir;
a4118ee1	429	ihold(old_dir);
d3d4152a	430	data->new_dir = new_dir;
a4118ee1	431	ihold(new_dir);
d3d4152a JL	432	data->old_dentry = dget(old_dentry);
	433	data->new_dentry = dget(new_dentry);
	434	nfs_fattr_init(&data->old_fattr);
	435	nfs_fattr_init(&data->new_fattr);
	436
	437	/* set up nfs_renameargs */
	438	data->args.old_dir = NFS_FH(old_dir);
	439	data->args.old_name = &old_dentry->d_name;
	440	data->args.new_dir = NFS_FH(new_dir);
	441	data->args.new_name = &new_dentry->d_name;
	442
	443	/* set up nfs_renameres */
	444	data->res.old_fattr = &data->old_fattr;
	445	data->res.new_fattr = &data->new_fattr;
	446
	447	nfs_sb_active(old_dir->i_sb);
	448
	449	NFS_PROTO(data->old_dir)->rename_setup(&msg, old_dir);
	450
f7732d65	451	return rpc_run_task(&task_setup_data);
d3d4152a JL	452	}
d3d4152a JL	453
779c5179 JL	454	/**
	455	* nfs_sillyrename - Perform a silly-rename of a dentry
	456	* @dir: inode of directory that contains dentry
	457	* @dentry: dentry to be sillyrenamed
	458	*
	459	* NFSv2/3 is stateless and the server doesn't know when the client is
	460	* holding a file open. To prevent application problems when a file is
	461	* unlinked while it's still open, the client performs a "silly-rename".
	462	* That is, it renames the file to a hidden file in the same directory,
	463	* and only performs the unlink once the last reference to it is put.
	464	*
	465	* The final cleanup is done during dentry_iput.
674e405b BF	466	*
	467	* (Note: NFSv4 is stateful, and has opens, so in theory an NFSv4 server
	468	* could take responsibility for keeping open files referenced. The server
	469	* would also need to ensure that opened-but-deleted files were kept over
	470	* reboots. However, we may not assume a server does so. (RFC 5661
	471	* does provide an OPEN4_RESULT_PRESERVE_UNLINKED flag that a server can
	472	* use to advertise that it does this; some day we may take advantage of
	473	* it.))
779c5179 JL	474	*/
	475	int
	476	nfs_sillyrename(struct inode dir, struct dentry dentry)
	477	{
	478	static unsigned int sillycounter;
	479	const int fileidsize = sizeof(NFS_FILEID(dentry->d_inode))*2;
	480	const int countersize = sizeof(sillycounter)*2;
	481	const int slen = sizeof(".nfs")+fileidsize+countersize-1;
	482	char silly[slen+1];
779c5179	483	struct dentry *sdentry;
d3d4152a	484	struct rpc_task *task;
779c5179 JL	485	int error = -EIO;
	486
	487	dfprintk(VFS, "NFS: silly-rename(%s/%s, ct=%d)\n",
	488	dentry->d_parent->d_name.name, dentry->d_name.name,
b7ab39f6	489	dentry->d_count);
779c5179 JL	490	nfs_inc_stats(dir, NFSIOS_SILLYRENAME);
	491
	492	/*
	493	* We don't allow a dentry to be silly-renamed twice.
	494	*/
	495	error = -EBUSY;
	496	if (dentry->d_flags & DCACHE_NFSFS_RENAMED)
	497	goto out;
	498
	499	sprintf(silly, ".nfs%.Lx",
	500	fileidsize, fileidsize,
	501	(unsigned long long)NFS_FILEID(dentry->d_inode));
	502
	503	/* Return delegation in anticipation of the rename */
57ec14c5	504	NFS_PROTO(dentry->d_inode)->return_delegation(dentry->d_inode);
779c5179 JL	505
	506	sdentry = NULL;
	507	do {
	508	char *suffix = silly + slen - countersize;
	509
	510	dput(sdentry);
	511	sillycounter++;
	512	sprintf(suffix, "%.x", countersize, countersize, sillycounter);
	513
	514	dfprintk(VFS, "NFS: trying to rename %s to %s\n",
	515	dentry->d_name.name, silly);
	516
	517	sdentry = lookup_one_len(silly, dentry->d_parent, slen);
	518	/*
	519	* N.B. Better to return EBUSY here ... it could be
	520	* dangerous to delete the file while it's in use.
	521	*/
	522	if (IS_ERR(sdentry))
	523	goto out;
	524	} while (sdentry->d_inode != NULL); /* need negative lookup */
	525
d3d4152a JL	526	/* queue unlink first. Can't do this from rpc_release as it
	527	* has to allocate memory
	528	*/
	529	error = nfs_async_unlink(dir, dentry);
	530	if (error)
	531	goto out_dput;
	532
73ca1001 JL	533	/* populate unlinkdata with the right dname */
	534	error = nfs_copy_dname(sdentry,
	535	(struct nfs_unlinkdata *)dentry->d_fsdata);
	536	if (error) {
	537	nfs_cancel_async_unlink(dentry);
	538	goto out_dput;
	539	}
	540
d3d4152a JL	541	/* run the rename task, undo unlink if it fails */
	542	task = nfs_async_rename(dir, dir, dentry, sdentry);
	543	if (IS_ERR(task)) {
	544	error = -EBUSY;
	545	nfs_cancel_async_unlink(dentry);
	546	goto out_dput;
779c5179	547	}
d3d4152a JL	548
	549	/* wait for the RPC task to complete, unless a SIGKILL intervenes */
	550	error = rpc_wait_for_completion_task(task);
	551	if (error == 0)
	552	error = task->tk_status;
	553	rpc_put_task(task);
	554	out_dput:
779c5179 JL	555	dput(sdentry);
	556	out:
	557	return error;
	558	}