Commit b0365ccb authored by Trond Myklebust's avatar Trond Myklebust
Browse files

NFS: Fix up forced readdirplus 



Avoid clearing the entire readdir page cache if we're just doing forced
readdirplus for the 'ls -l' heuristic.

Signed-off-by: default avatarTrond Myklebust <trond.myklebust@hammerspace.com>
parent f648022f

fs/nfs/dir.c

+39 −17
Original line number Diff line number Diff line
@@ -170,6 +170,7 @@ struct nfs_readdir_descriptor { 
	unsigned int	cache_entry_index;

	unsigned int	buffer_fills;

	unsigned int	dtsize;

	bool clear_cache;

	bool plus;

	bool eob;

	bool eof;
@@ -227,6 +228,13 @@ static void nfs_readdir_clear_array(struct page *page) 
	kunmap_atomic(array);

}



static void nfs_readdir_page_reinit_array(struct page *page, u64 last_cookie,

					  u64 change_attr)

{

	nfs_readdir_clear_array(page);

	nfs_readdir_page_init_array(page, last_cookie, change_attr);

}



static struct page *

nfs_readdir_page_array_alloc(u64 last_cookie, gfp_t gfp_flags)

{
@@ -428,12 +436,11 @@ static struct page *nfs_readdir_page_get_next(struct address_space *mapping, 
	struct page *page;



	page = nfs_readdir_page_get_locked(mapping, cookie, change_attr);

	if (page) {

		if (nfs_readdir_page_last_cookie(page) == cookie)

			return page;

		nfs_readdir_page_unlock_and_put(page);

	}

	if (!page)

		return NULL;

	if (nfs_readdir_page_last_cookie(page) != cookie)

		nfs_readdir_page_reinit_array(page, cookie, change_attr);

	return page;

}



static inline
@@ -960,9 +967,15 @@ nfs_readdir_page_get_cached(struct nfs_readdir_descriptor *desc) 
{

	struct address_space *mapping = desc->file->f_mapping;

	u64 change_attr = inode_peek_iversion_raw(mapping->host);

	u64 cookie = desc->last_cookie;

	struct page *page;



	return nfs_readdir_page_get_locked(mapping, desc->last_cookie,

					   change_attr);

	page = nfs_readdir_page_get_locked(mapping, cookie, change_attr);

	if (!page)

		return NULL;

	if (desc->clear_cache && !nfs_readdir_page_needs_filling(page))

		nfs_readdir_page_reinit_array(page, cookie, change_attr);

	return page;

}



/*
@@ -1013,6 +1026,7 @@ static int find_and_lock_cache_page(struct nfs_readdir_descriptor *desc) 
			trace_nfs_readdir_invalidate_cache_range(

				inode, 1, MAX_LFS_FILESIZE);

		}

		desc->clear_cache = false;

	}

	res = nfs_readdir_search_array(desc);

	if (res == 0)
@@ -1147,16 +1161,17 @@ static int uncached_readdir(struct nfs_readdir_descriptor *desc) 


#define NFS_READDIR_CACHE_MISS_THRESHOLD (16UL)



static void nfs_readdir_handle_cache_misses(struct inode *inode,

static bool nfs_readdir_handle_cache_misses(struct inode *inode,

					    struct nfs_readdir_descriptor *desc,

					    unsigned int cache_misses)

					    unsigned int cache_misses,

					    bool force_clear)

{

	if (desc->ctx->pos == 0 ||

	    cache_misses <= NFS_READDIR_CACHE_MISS_THRESHOLD)

		return;

	if (invalidate_mapping_pages(inode->i_mapping, 0, -1) == 0)

		return;

	trace_nfs_readdir_invalidate_cache_range(inode, 0, MAX_LFS_FILESIZE);

	if (desc->ctx->pos == 0 || !desc->plus)

		return false;

	if (cache_misses <= NFS_READDIR_CACHE_MISS_THRESHOLD && !force_clear)

		return false;

	trace_nfs_readdir_force_readdirplus(inode);

	return true;

}



/* The file offset position represents the dirent entry number.  A
@@ -1171,6 +1186,7 @@ static int nfs_readdir(struct file *file, struct dir_context *ctx) 
	struct nfs_open_dir_context *dir_ctx = file->private_data;

	struct nfs_readdir_descriptor *desc;

	unsigned int cache_hits, cache_misses;

	bool force_clear;

	int res;



	dfprintk(FILE, "NFS: readdir(%pD2) starting at cookie %llu\n",
@@ -1203,6 +1219,7 @@ static int nfs_readdir(struct file *file, struct dir_context *ctx) 
	memcpy(desc->verf, dir_ctx->verf, sizeof(desc->verf));

	cache_hits = atomic_xchg(&dir_ctx->cache_hits, 0);

	cache_misses = atomic_xchg(&dir_ctx->cache_misses, 0);

	force_clear = dir_ctx->force_clear;

	spin_unlock(&file->f_lock);



	if (desc->eof) {
@@ -1211,7 +1228,9 @@ static int nfs_readdir(struct file *file, struct dir_context *ctx) 
	}



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

	nfs_readdir_handle_cache_misses(inode, desc, cache_misses);

	force_clear = nfs_readdir_handle_cache_misses(inode, desc, cache_misses,

						      force_clear);

	desc->clear_cache = force_clear;



	do {

		res = readdir_search_pagecache(desc);
@@ -1240,6 +1259,8 @@ static int nfs_readdir(struct file *file, struct dir_context *ctx) 


		nfs_do_filldir(desc, nfsi->cookieverf);

		nfs_readdir_page_unlock_and_put_cached(desc);

		if (desc->page_index == desc->page_index_max)

			desc->clear_cache = force_clear;

	} while (!desc->eob && !desc->eof);



	spin_lock(&file->f_lock);
@@ -1247,6 +1268,7 @@ static int nfs_readdir(struct file *file, struct dir_context *ctx) 
	dir_ctx->last_cookie = desc->last_cookie;

	dir_ctx->attr_gencount = desc->attr_gencount;

	dir_ctx->page_index = desc->page_index;

	dir_ctx->force_clear = force_clear;

	dir_ctx->eof = desc->eof;

	dir_ctx->dtsize = desc->dtsize;

	memcpy(dir_ctx->verf, desc->verf, sizeof(dir_ctx->verf));

fs/nfs/nfstrace.h

+1 −0
Original line number Diff line number Diff line
@@ -160,6 +160,7 @@ DEFINE_NFS_INODE_EVENT(nfs_fsync_enter); 
DEFINE_NFS_INODE_EVENT_DONE(nfs_fsync_exit);

DEFINE_NFS_INODE_EVENT(nfs_access_enter);

DEFINE_NFS_INODE_EVENT_DONE(nfs_set_cache_invalid);

DEFINE_NFS_INODE_EVENT(nfs_readdir_force_readdirplus);

DEFINE_NFS_INODE_EVENT_DONE(nfs_readdir_cache_fill_done);

DEFINE_NFS_INODE_EVENT_DONE(nfs_readdir_uncached_done);

include/linux/nfs_fs.h

+1 −0
Original line number Diff line number Diff line
@@ -109,6 +109,7 @@ struct nfs_open_dir_context { 
	__u64 last_cookie;

	pgoff_t page_index;

	unsigned int dtsize;

	bool force_clear;

	bool eof;

	struct rcu_head rcu_head;

};