Commit 6b75cf9e authored by Trond Myklebust's avatar Trond Myklebust
Browse files

NFS: Reduce readdir stack usage 



The descriptor and the struct nfs_entry are both large structures,
so don't allocate them from the stack.

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 dbeaf8c9

fs/nfs/dir.c

+33 −25
Original line number Diff line number Diff line
@@ -761,23 +761,24 @@ static 
int nfs_readdir_xdr_to_array(nfs_readdir_descriptor_t *desc, struct page *page, struct inode *inode)

{

	struct page **pages;

	struct nfs_entry entry;

	struct nfs_entry *entry;

	size_t array_size;

	size_t dtsize = NFS_SERVER(inode)->dtsize;

	int status = -ENOMEM;



	entry.prev_cookie = 0;

	entry.cookie = nfs_readdir_page_last_cookie(page);

	entry.eof = 0;

	entry.fh = nfs_alloc_fhandle();

	entry.fattr = nfs_alloc_fattr();

	entry.server = NFS_SERVER(inode);

	if (entry.fh == NULL || entry.fattr == NULL)

	entry = kzalloc(sizeof(*entry), GFP_KERNEL);

	if (!entry)

		return -ENOMEM;

	entry->cookie = nfs_readdir_page_last_cookie(page);

	entry->fh = nfs_alloc_fhandle();

	entry->fattr = nfs_alloc_fattr();

	entry->server = NFS_SERVER(inode);

	if (entry->fh == NULL || entry->fattr == NULL)

		goto out;



	entry.label = nfs4_label_alloc(NFS_SERVER(inode), GFP_NOWAIT);

	if (IS_ERR(entry.label)) {

		status = PTR_ERR(entry.label);

	entry->label = nfs4_label_alloc(NFS_SERVER(inode), GFP_NOWAIT);

	if (IS_ERR(entry->label)) {

		status = PTR_ERR(entry->label);

		goto out;

	}
@@ -788,7 +789,7 @@ int nfs_readdir_xdr_to_array(nfs_readdir_descriptor_t *desc, struct page *page, 


	do {

		unsigned int pglen;

		status = nfs_readdir_xdr_filler(desc, entry.cookie,

		status = nfs_readdir_xdr_filler(desc, entry->cookie,

						pages, dtsize);

		if (status < 0)

			break;
@@ -799,15 +800,16 @@ int nfs_readdir_xdr_to_array(nfs_readdir_descriptor_t *desc, struct page *page, 
			break;

		}



		status = nfs_readdir_page_filler(desc, &entry, pages, page, pglen);

		status = nfs_readdir_page_filler(desc, entry, pages, page, pglen);

	} while (!status && nfs_readdir_page_needs_filling(page));



	nfs_readdir_free_pages(pages, array_size);

out_release_label:

	nfs4_label_free(entry.label);

	nfs4_label_free(entry->label);

out:

	nfs_free_fattr(entry.fattr);

	nfs_free_fhandle(entry.fh);

	nfs_free_fattr(entry->fattr);

	nfs_free_fhandle(entry->fh);

	kfree(entry);

	return status;

}
@@ -974,13 +976,8 @@ static int nfs_readdir(struct file *file, struct dir_context *ctx) 
	struct dentry	*dentry = file_dentry(file);

	struct inode	*inode = d_inode(dentry);

	struct nfs_open_dir_context *dir_ctx = file->private_data;

	nfs_readdir_descriptor_t my_desc = {

		.file = file,

		.ctx = ctx,

		.plus = nfs_use_readdirplus(inode, ctx),

	},

			*desc = &my_desc;

	int res = 0;

	struct nfs_readdir_descriptor *desc;

	int res;



	dfprintk(FILE, "NFS: readdir(%pD2) starting at cookie %llu\n",

			file, (long long)ctx->pos);
@@ -992,10 +989,19 @@ static int nfs_readdir(struct file *file, struct dir_context *ctx) 
	 * to either find the entry with the appropriate number or

	 * revalidate the cookie.

	 */

	if (ctx->pos == 0 || nfs_attribute_cache_expired(inode))

	if (ctx->pos == 0 || nfs_attribute_cache_expired(inode)) {

		res = nfs_revalidate_mapping(inode, file->f_mapping);

		if (res < 0)

			goto out;

	}



	res = -ENOMEM;

	desc = kzalloc(sizeof(*desc), GFP_KERNEL);

	if (!desc)

		goto out;

	desc->file = file;

	desc->ctx = ctx;

	desc->plus = nfs_use_readdirplus(inode, ctx);



	spin_lock(&file->f_lock);

	desc->dir_cookie = dir_ctx->dir_cookie;
@@ -1040,6 +1046,8 @@ static int nfs_readdir(struct file *file, struct dir_context *ctx) 
	dir_ctx->attr_gencount = desc->attr_gencount;

	spin_unlock(&file->f_lock);



	kfree(desc);



out:

	dfprintk(FILE, "NFS: readdir(%pD2) returns %d\n", file, res);

	return res;