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NFS: Fix up forced readdirplus

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

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
This commit is contained in:
Trond Myklebust 2022-02-23 13:29:59 -05:00
parent f648022faa
commit b0365ccb07
3 changed files with 41 additions and 17 deletions
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56
fs/nfs/dir.c
View File

@ -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);
}
return NULL;
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 @@ out:
#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));

1
fs/nfs/nfstrace.h
View File

@ -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);

1
include/linux/nfs_fs.h
View File

@ -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;
};