2021-01-20 17:03:53

by Benjamin Coddington

[permalink] [raw]
Subject: [PATCH v1 03/10] NFS: Add a struct to track readdir pagecache location

Directory entries in the NFS readdir pagecache are referenced by their
cookie value and offset. By defining a structure to group these values,
we'll simplify changes to validate pagecache pages in patches that follow.

Signed-off-by: Benjamin Coddington <[email protected]>
---
fs/nfs/dir.c | 34 +++++++++++++++++-----------------
include/linux/nfs_fs.h | 6 ++++++
2 files changed, 23 insertions(+), 17 deletions(-)

diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index ade73ca42a52..6626aff9f54d 100644
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -154,10 +154,9 @@ struct nfs_readdir_descriptor {
struct file *file;
struct page *page;
struct dir_context *ctx;
- pgoff_t page_index;
u64 dir_cookie;
- u64 last_cookie;
u64 dup_cookie;
+ struct nfs_dir_page_cursor pgc;
loff_t current_index;
loff_t prev_index;

@@ -166,7 +165,6 @@ struct nfs_readdir_descriptor {
unsigned long timestamp;
unsigned long gencount;
unsigned long attr_gencount;
- unsigned int cache_entry_index;
signed char duped;
bool plus;
bool eof;
@@ -426,7 +424,7 @@ static int nfs_readdir_search_for_pos(struct nfs_cache_array *array,

index = (unsigned int)diff;
desc->dir_cookie = array->array[index].cookie;
- desc->cache_entry_index = index;
+ desc->pgc.entry_index = index;
return 0;
out_eof:
desc->eof = true;
@@ -494,7 +492,7 @@ static int nfs_readdir_search_for_cookie(struct nfs_cache_array *array,
else
desc->ctx->pos = new_pos;
desc->prev_index = new_pos;
- desc->cache_entry_index = i;
+ desc->pgc.entry_index = i;
return 0;
}
}
@@ -521,9 +519,9 @@ static int nfs_readdir_search_array(struct nfs_readdir_descriptor *desc)
status = nfs_readdir_search_for_cookie(array, desc);

if (status == -EAGAIN) {
- desc->last_cookie = array->last_cookie;
+ desc->pgc.index_cookie = array->last_cookie;
desc->current_index += array->size;
- desc->page_index++;
+ desc->pgc.page_index++;
}
kunmap_atomic(array);
return status;
@@ -927,8 +925,8 @@ static struct page *
nfs_readdir_page_get_cached(struct nfs_readdir_descriptor *desc)
{
return nfs_readdir_page_get_locked(desc->file->f_mapping,
- desc->page_index,
- desc->last_cookie);
+ desc->pgc.page_index,
+ desc->pgc.index_cookie);
}

/*
@@ -952,7 +950,7 @@ static int find_and_lock_cache_page(struct nfs_readdir_descriptor *desc)
nfs_readdir_page_unlock_and_put_cached(desc);
if (res == -EBADCOOKIE || res == -ENOTSYNC) {
invalidate_inode_pages2(desc->file->f_mapping);
- desc->page_index = 0;
+ desc->pgc.page_index = 0;
return -EAGAIN;
}
return res;
@@ -961,7 +959,7 @@ static int find_and_lock_cache_page(struct nfs_readdir_descriptor *desc)
}
res = nfs_readdir_search_array(desc);
if (res == 0) {
- nfsi->page_index = desc->page_index;
+ nfsi->page_index = desc->pgc.page_index;
return 0;
}
nfs_readdir_page_unlock_and_put_cached(desc);
@@ -991,10 +989,10 @@ static int readdir_search_pagecache(struct nfs_readdir_descriptor *desc)
return -EBADCOOKIE;

do {
- if (desc->page_index == 0) {
+ if (desc->pgc.page_index == 0) {
desc->current_index = 0;
desc->prev_index = 0;
- desc->last_cookie = 0;
+ desc->pgc.index_cookie = 0;
}
res = find_and_lock_cache_page(desc);
} while (res == -EAGAIN);
@@ -1012,7 +1010,7 @@ static void nfs_do_filldir(struct nfs_readdir_descriptor *desc)
unsigned int i = 0;

array = kmap(desc->page);
- for (i = desc->cache_entry_index; i < array->size; i++) {
+ for (i = desc->pgc.entry_index; i < array->size; i++) {
struct nfs_cache_array_entry *ent;

ent = &array->array[i];
@@ -1070,8 +1068,10 @@ static int uncached_readdir(struct nfs_readdir_descriptor *desc)
if (!arrays[0])
goto out;

- desc->page_index = 0;
- desc->last_cookie = desc->dir_cookie;
+ /* These values aren't referenced until we return, move/remove? */
+ desc->pgc.page_index = 0;
+ desc->pgc.index_cookie = desc->dir_cookie;
+
desc->duped = 0;

status = nfs_readdir_xdr_to_array(desc, desc->verf, verf, arrays, sz);
@@ -1154,7 +1154,7 @@ static int nfs_readdir(struct file *file, struct dir_context *ctx)
if (res == -ETOOSMALL && desc->plus) {
clear_bit(NFS_INO_ADVISE_RDPLUS, &NFS_I(inode)->flags);
nfs_zap_caches(inode);
- desc->page_index = 0;
+ desc->pgc.page_index = 0;
desc->plus = false;
desc->eof = false;
continue;
diff --git a/include/linux/nfs_fs.h b/include/linux/nfs_fs.h
index 681ed98e4ba8..557e54b7d555 100644
--- a/include/linux/nfs_fs.h
+++ b/include/linux/nfs_fs.h
@@ -91,6 +91,12 @@ struct nfs_open_context {
struct rcu_head rcu_head;
};

+struct nfs_dir_page_cursor {
+ __u64 index_cookie;
+ pgoff_t page_index;
+ unsigned int entry_index;
+};
+
struct nfs_open_dir_context {
struct list_head list;
unsigned long attr_gencount;
--
2.25.4