Commit 2e7a4641 authored by Trond Myklebust's avatar Trond Myklebust
Browse files

NFS: Ensure contents of struct nfs_open_dir_context are consistent 



Ensure that the contents of struct nfs_open_dir_context are consistent
by setting them under the file->f_lock from a private copy (that is
known to be consistent).

Signed-off-by: default avatarTrond Myklebust <trond.myklebust@hammerspace.com>
Reviewed-by: default avatarBenjamin Coddington <bcodding@redhat.com>
Tested-by: default avatarBenjamin Coddington <bcodding@redhat.com>
Tested-by: default avatarDave Wysochanski <dwysocha@redhat.com>
parent 05ad9175

fs/nfs/dir.c

+43 −29
Original line number Diff line number Diff line
@@ -144,20 +144,23 @@ struct nfs_cache_array { 
	struct nfs_cache_array_entry array[];

};



typedef struct {

typedef struct nfs_readdir_descriptor {

	struct file	*file;

	struct page	*page;

	struct dir_context *ctx;

	unsigned long	page_index;

	u64		*dir_cookie;

	u64		dir_cookie;

	u64		last_cookie;

	u64		dup_cookie;

	loff_t		current_index;

	loff_t		prev_index;



	unsigned long	dir_verifier;

	unsigned long	timestamp;

	unsigned long	gencount;

	unsigned long	attr_gencount;

	unsigned int	cache_entry_index;

	signed char duped;

	bool plus;

	bool eof;

} nfs_readdir_descriptor_t;
@@ -273,7 +276,7 @@ int nfs_readdir_search_for_pos(struct nfs_cache_array *array, nfs_readdir_descri 
	}



	index = (unsigned int)diff;

	*desc->dir_cookie = array->array[index].cookie;

	desc->dir_cookie = array->array[index].cookie;

	desc->cache_entry_index = index;

	return 0;

out_eof:
@@ -298,33 +301,32 @@ int nfs_readdir_search_for_cookie(struct nfs_cache_array *array, nfs_readdir_des 
	int status = -EAGAIN;



	for (i = 0; i < array->size; i++) {

		if (array->array[i].cookie == *desc->dir_cookie) {

		if (array->array[i].cookie == desc->dir_cookie) {

			struct nfs_inode *nfsi = NFS_I(file_inode(desc->file));

			struct nfs_open_dir_context *ctx = desc->file->private_data;



			new_pos = desc->current_index + i;

			if (ctx->attr_gencount != nfsi->attr_gencount ||

			if (desc->attr_gencount != nfsi->attr_gencount ||

			    !nfs_readdir_inode_mapping_valid(nfsi)) {

				ctx->duped = 0;

				ctx->attr_gencount = nfsi->attr_gencount;

				desc->duped = 0;

				desc->attr_gencount = nfsi->attr_gencount;

			} else if (new_pos < desc->prev_index) {

				if (ctx->duped > 0

				    && ctx->dup_cookie == *desc->dir_cookie) {

				if (desc->duped > 0

				    && desc->dup_cookie == desc->dir_cookie) {

					if (printk_ratelimit()) {

						pr_notice("NFS: directory %pD2 contains a readdir loop."

								"Please contact your server vendor.  "

								"The file: %.*s has duplicate cookie %llu\n",

								desc->file, array->array[i].string.len,

								array->array[i].string.name, *desc->dir_cookie);

								array->array[i].string.name, desc->dir_cookie);

					}

					status = -ELOOP;

					goto out;

				}

				ctx->dup_cookie = *desc->dir_cookie;

				ctx->duped = -1;

				desc->dup_cookie = desc->dir_cookie;

				desc->duped = -1;

			}

			if (nfs_readdir_use_cookie(desc->file))

				desc->ctx->pos = *desc->dir_cookie;

				desc->ctx->pos = desc->dir_cookie;

			else

				desc->ctx->pos = new_pos;

			desc->prev_index = new_pos;
@@ -334,7 +336,7 @@ int nfs_readdir_search_for_cookie(struct nfs_cache_array *array, nfs_readdir_des 
	}

	if (array->eof_index >= 0) {

		status = -EBADCOOKIE;

		if (*desc->dir_cookie == array->last_cookie)

		if (desc->dir_cookie == array->last_cookie)

			desc->eof = true;

	}

out:
@@ -349,7 +351,7 @@ int nfs_readdir_search_array(nfs_readdir_descriptor_t *desc) 


	array = kmap(desc->page);



	if (*desc->dir_cookie == 0)

	if (desc->dir_cookie == 0)

		status = nfs_readdir_search_for_pos(array, desc);

	else

		status = nfs_readdir_search_for_cookie(array, desc);
@@ -801,7 +803,6 @@ int nfs_do_filldir(nfs_readdir_descriptor_t *desc) 
	int i = 0;

	int res = 0;

	struct nfs_cache_array *array = NULL;

	struct nfs_open_dir_context *ctx = file->private_data;



	array = kmap(desc->page);

	for (i = desc->cache_entry_index; i < array->size; i++) {
@@ -814,22 +815,22 @@ int nfs_do_filldir(nfs_readdir_descriptor_t *desc) 
			break;

		}

		if (i < (array->size-1))

			*desc->dir_cookie = array->array[i+1].cookie;

			desc->dir_cookie = array->array[i+1].cookie;

		else

			*desc->dir_cookie = array->last_cookie;

			desc->dir_cookie = array->last_cookie;

		if (nfs_readdir_use_cookie(file))

			desc->ctx->pos = *desc->dir_cookie;

			desc->ctx->pos = desc->dir_cookie;

		else

			desc->ctx->pos++;

		if (ctx->duped != 0)

			ctx->duped = 1;

		if (desc->duped != 0)

			desc->duped = 1;

	}

	if (array->eof_index >= 0)

		desc->eof = true;



	kunmap(desc->page);

	dfprintk(DIRCACHE, "NFS: nfs_do_filldir() filling ended @ cookie %Lu; returning = %d\n",

			(unsigned long long)*desc->dir_cookie, res);

			(unsigned long long)desc->dir_cookie, res);

	return res;

}
@@ -851,10 +852,9 @@ int uncached_readdir(nfs_readdir_descriptor_t *desc) 
	struct page	*page = NULL;

	int		status;

	struct inode *inode = file_inode(desc->file);

	struct nfs_open_dir_context *ctx = desc->file->private_data;



	dfprintk(DIRCACHE, "NFS: uncached_readdir() searching for cookie %Lu\n",

			(unsigned long long)*desc->dir_cookie);

			(unsigned long long)desc->dir_cookie);



	page = alloc_page(GFP_HIGHUSER);

	if (!page) {
@@ -863,9 +863,9 @@ int uncached_readdir(nfs_readdir_descriptor_t *desc) 
	}



	desc->page_index = 0;

	desc->last_cookie = *desc->dir_cookie;

	desc->last_cookie = desc->dir_cookie;

	desc->page = page;

	ctx->duped = 0;

	desc->duped = 0;



	status = nfs_readdir_xdr_to_array(desc, page, inode);

	if (status < 0)
@@ -894,7 +894,6 @@ static int nfs_readdir(struct file *file, struct dir_context *ctx) 
	nfs_readdir_descriptor_t my_desc = {

		.file = file,

		.ctx = ctx,

		.dir_cookie = &dir_ctx->dir_cookie,

		.plus = nfs_use_readdirplus(inode, ctx),

	},

			*desc = &my_desc;
@@ -915,13 +914,20 @@ static int nfs_readdir(struct file *file, struct dir_context *ctx) 
	if (res < 0)

		goto out;



	spin_lock(&file->f_lock);

	desc->dir_cookie = dir_ctx->dir_cookie;

	desc->dup_cookie = dir_ctx->dup_cookie;

	desc->duped = dir_ctx->duped;

	desc->attr_gencount = dir_ctx->attr_gencount;

	spin_unlock(&file->f_lock);



	do {

		res = readdir_search_pagecache(desc);



		if (res == -EBADCOOKIE) {

			res = 0;

			/* This means either end of directory */

			if (*desc->dir_cookie && !desc->eof) {

			if (desc->dir_cookie && !desc->eof) {

				/* Or that the server has 'lost' a cookie */

				res = uncached_readdir(desc);

				if (res == 0)
@@ -946,6 +952,14 @@ static int nfs_readdir(struct file *file, struct dir_context *ctx) 
		if (res < 0)

			break;

	} while (!desc->eof);



	spin_lock(&file->f_lock);

	dir_ctx->dir_cookie = desc->dir_cookie;

	dir_ctx->dup_cookie = desc->dup_cookie;

	dir_ctx->duped = desc->duped;

	dir_ctx->attr_gencount = desc->attr_gencount;

	spin_unlock(&file->f_lock);



out:

	if (res > 0)

		res = 0;