From: trondmy@kernel.org
To: linux-nfs@vger.kernel.org
Subject: [PATCH v10 13/26] NFS: Reduce use of uncached readdir
Date: Sun, 13 Mar 2022 13:05:44 -0400 [thread overview]
Message-ID: <20220313170557.5940-14-trondmy@kernel.org> (raw)
In-Reply-To: <20220313170557.5940-13-trondmy@kernel.org>
From: Trond Myklebust <trond.myklebust@hammerspace.com>
When reading a very large directory, we want to try to keep the page
cache up to date if doing so is inexpensive. With the change to allow
readdir to continue reading even when the cache is incomplete, we no
longer need to fall back to uncached readdir in order to scale to large
directories.
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
---
fs/nfs/dir.c | 23 +++--------------------
1 file changed, 3 insertions(+), 20 deletions(-)
diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index 9d086ab4f889..dc6acfd14fc7 100644
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -999,28 +999,11 @@ static int find_and_lock_cache_page(struct nfs_readdir_descriptor *desc)
return res;
}
-static bool nfs_readdir_dont_search_cache(struct nfs_readdir_descriptor *desc)
-{
- struct address_space *mapping = desc->file->f_mapping;
- struct inode *dir = file_inode(desc->file);
- unsigned int dtsize = NFS_SERVER(dir)->dtsize;
- loff_t size = i_size_read(dir);
-
- /*
- * Default to uncached readdir if the page cache is empty, and
- * we're looking for a non-zero cookie in a large directory.
- */
- return desc->dir_cookie != 0 && mapping->nrpages == 0 && size > dtsize;
-}
-
/* Search for desc->dir_cookie from the beginning of the page cache */
static int readdir_search_pagecache(struct nfs_readdir_descriptor *desc)
{
int res;
- if (nfs_readdir_dont_search_cache(desc))
- return -EBADCOOKIE;
-
do {
if (desc->page_index == 0) {
desc->current_index = 0;
@@ -1273,10 +1256,10 @@ static loff_t nfs_llseek_dir(struct file *filp, loff_t offset, int whence)
}
if (offset != filp->f_pos) {
filp->f_pos = offset;
- if (!nfs_readdir_use_cookie(filp)) {
+ dir_ctx->page_index = 0;
+ if (!nfs_readdir_use_cookie(filp))
dir_ctx->dir_cookie = 0;
- dir_ctx->page_index = 0;
- } else
+ else
dir_ctx->dir_cookie = offset;
if (offset == 0)
memset(dir_ctx->verf, 0, sizeof(dir_ctx->verf));
--
2.35.1
next prev parent reply other threads:[~2022-03-13 17:12 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-03-13 17:05 [PATCH v10 00/26] Readdir improvements trondmy
2022-03-13 17:05 ` [PATCH v10 01/26] NFS: Return valid errors from nfs2/3_decode_dirent() trondmy
2022-03-13 17:05 ` [PATCH v10 02/26] NFS: constify nfs_server_capable() and nfs_have_writebacks() trondmy
2022-03-13 17:05 ` [PATCH v10 03/26] NFS: Trace lookup revalidation failure trondmy
2022-03-13 17:05 ` [PATCH v10 04/26] NFS: Initialise the readdir verifier as best we can in nfs_opendir() trondmy
2022-03-13 17:05 ` [PATCH v10 05/26] NFS: Use kzalloc() to avoid initialising the nfs_open_dir_context trondmy
2022-03-13 17:05 ` [PATCH v10 06/26] NFS: Calculate page offsets algorithmically trondmy
2022-03-13 17:05 ` [PATCH v10 07/26] NFS: Store the change attribute in the directory page cache trondmy
2022-03-13 17:05 ` [PATCH v10 08/26] NFS: Don't re-read the entire page cache to find the next cookie trondmy
2022-03-13 17:05 ` [PATCH v10 09/26] NFS: Don't advance the page pointer unless the page is full trondmy
2022-03-13 17:05 ` [PATCH v10 10/26] NFS: Adjust the amount of readahead performed by NFS readdir trondmy
2022-03-13 17:05 ` [PATCH v10 11/26] NFS: If the cookie verifier changes, we must invalidate the page cache trondmy
2022-03-13 17:05 ` [PATCH v10 12/26] NFS: Simplify nfs_readdir_xdr_to_array() trondmy
2022-03-13 17:05 ` trondmy [this message]
2022-03-13 17:05 ` [PATCH v10 14/26] NFS: Improve heuristic for readdirplus trondmy
2022-03-13 17:05 ` [PATCH v10 15/26] NFS: Don't ask for readdirplus unless it can help nfs_getattr() trondmy
2022-03-13 17:05 ` [PATCH v10 16/26] NFSv4: Ask for a full XDR buffer of readdir goodness trondmy
2022-03-13 17:05 ` [PATCH v10 17/26] NFS: Readdirplus can't help lookup for case insensitive filesystems trondmy
2022-03-13 17:05 ` [PATCH v10 18/26] NFS: Don't request readdirplus when revalidation was forced trondmy
2022-03-13 17:05 ` [PATCH v10 19/26] NFS: Add basic readdir tracing trondmy
2022-03-13 17:05 ` [PATCH v10 20/26] NFS: Trace effects of readdirplus on the dcache trondmy
2022-03-13 17:05 ` [PATCH v10 21/26] NFS: Trace effects of the readdirplus heuristic trondmy
2022-03-13 17:05 ` [PATCH v10 22/26] NFS: Clean up page array initialisation/free trondmy
2022-03-13 17:05 ` [PATCH v10 23/26] NFS: Convert readdir page cache to use a cookie based index trondmy
2022-03-13 17:05 ` [PATCH v10 24/26] NFS: Fix up forced readdirplus trondmy
2022-03-13 17:05 ` [PATCH v10 25/26] NFS: Optimise away the previous cookie field trondmy
2022-03-13 17:05 ` [PATCH v10 26/26] NFS: Cache all entries in the readdirplus reply trondmy
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