2022-02-23 23:38:54

by Trond Myklebust

[permalink] [raw]
Subject: [PATCH v7 12/21] NFS: Don't ask for readdirplus unless it can help nfs_getattr()

From: Trond Myklebust <[email protected]>

If attribute caching is turned off, then use of readdirplus is not going
to help stat() performance.
Readdirplus also doesn't help if a file is being written to, since we
will have to flush those writes in order to sync the mtime/ctime.

Signed-off-by: Trond Myklebust <[email protected]>
---
fs/nfs/inode.c | 33 +++++++++++++++++----------------
1 file changed, 17 insertions(+), 16 deletions(-)

diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c
index bbf4357ff727..10d17cfb8639 100644
--- a/fs/nfs/inode.c
+++ b/fs/nfs/inode.c
@@ -780,24 +780,26 @@ void nfs_setattr_update_inode(struct inode *inode, struct iattr *attr,
}
EXPORT_SYMBOL_GPL(nfs_setattr_update_inode);

-static void nfs_readdirplus_parent_cache_miss(struct dentry *dentry)
+/*
+ * Don't request help from readdirplus if the file is being written to,
+ * or if attribute caching is turned off
+ */
+static bool nfs_getattr_readdirplus_enable(const struct inode *inode)
{
- struct dentry *parent;
+ return nfs_server_capable(inode, NFS_CAP_READDIRPLUS) &&
+ !nfs_have_writebacks(inode) && NFS_MAXATTRTIMEO(inode) > 5 * HZ;
+}

- if (!nfs_server_capable(d_inode(dentry), NFS_CAP_READDIRPLUS))
- return;
- parent = dget_parent(dentry);
+static void nfs_readdirplus_parent_cache_miss(struct dentry *dentry)
+{
+ struct dentry *parent = dget_parent(dentry);
nfs_readdir_record_entry_cache_miss(d_inode(parent));
dput(parent);
}

static void nfs_readdirplus_parent_cache_hit(struct dentry *dentry)
{
- struct dentry *parent;
-
- if (!nfs_server_capable(d_inode(dentry), NFS_CAP_READDIRPLUS))
- return;
- parent = dget_parent(dentry);
+ struct dentry *parent = dget_parent(dentry);
nfs_readdir_record_entry_cache_hit(d_inode(parent));
dput(parent);
}
@@ -835,6 +837,7 @@ int nfs_getattr(struct user_namespace *mnt_userns, const struct path *path,
int err = 0;
bool force_sync = query_flags & AT_STATX_FORCE_SYNC;
bool do_update = false;
+ bool readdirplus_enabled = nfs_getattr_readdirplus_enable(inode);

trace_nfs_getattr_enter(inode);

@@ -843,7 +846,8 @@ int nfs_getattr(struct user_namespace *mnt_userns, const struct path *path,
STATX_INO | STATX_SIZE | STATX_BLOCKS;

if ((query_flags & AT_STATX_DONT_SYNC) && !force_sync) {
- nfs_readdirplus_parent_cache_hit(path->dentry);
+ if (readdirplus_enabled)
+ nfs_readdirplus_parent_cache_hit(path->dentry);
goto out_no_revalidate;
}

@@ -893,15 +897,12 @@ int nfs_getattr(struct user_namespace *mnt_userns, const struct path *path,
do_update |= cache_validity & NFS_INO_INVALID_BLOCKS;

if (do_update) {
- /* Update the attribute cache */
- if (!(server->flags & NFS_MOUNT_NOAC))
+ if (readdirplus_enabled)
nfs_readdirplus_parent_cache_miss(path->dentry);
- else
- nfs_readdirplus_parent_cache_hit(path->dentry);
err = __nfs_revalidate_inode(server, inode);
if (err)
goto out;
- } else
+ } else if (readdirplus_enabled)
nfs_readdirplus_parent_cache_hit(path->dentry);
out_no_revalidate:
/* Only return attributes that were revalidated. */
--
2.35.1


2022-02-24 00:52:10

by Trond Myklebust

[permalink] [raw]
Subject: [PATCH v7 13/21] NFSv4: Ask for a full XDR buffer of readdir goodness

From: Trond Myklebust <[email protected]>

Instead of pretending that we know the ratio of directory info vs
readdirplus attribute info, just set the 'dircount' field to the same
value as the 'maxcount' field.

Signed-off-by: Trond Myklebust <[email protected]>
---
fs/nfs/nfs3xdr.c | 7 ++++---
fs/nfs/nfs4xdr.c | 6 +++---
2 files changed, 7 insertions(+), 6 deletions(-)

diff --git a/fs/nfs/nfs3xdr.c b/fs/nfs/nfs3xdr.c
index 54a1d21cbcc6..296320f91579 100644
--- a/fs/nfs/nfs3xdr.c
+++ b/fs/nfs/nfs3xdr.c
@@ -1261,6 +1261,8 @@ static void nfs3_xdr_enc_readdir3args(struct rpc_rqst *req,
static void encode_readdirplus3args(struct xdr_stream *xdr,
const struct nfs3_readdirargs *args)
{
+ uint32_t dircount = args->count;
+ uint32_t maxcount = args->count;
__be32 *p;

encode_nfs_fh3(xdr, args->fh);
@@ -1273,9 +1275,8 @@ static void encode_readdirplus3args(struct xdr_stream *xdr,
* readdirplus: need dircount + buffer size.
* We just make sure we make dircount big enough
*/
- *p++ = cpu_to_be32(args->count >> 3);
-
- *p = cpu_to_be32(args->count);
+ *p++ = cpu_to_be32(dircount);
+ *p = cpu_to_be32(maxcount);
}

static void nfs3_xdr_enc_readdirplus3args(struct rpc_rqst *req,
diff --git a/fs/nfs/nfs4xdr.c b/fs/nfs/nfs4xdr.c
index 8e70b92df4cc..b7780b97dc4d 100644
--- a/fs/nfs/nfs4xdr.c
+++ b/fs/nfs/nfs4xdr.c
@@ -1605,7 +1605,8 @@ static void encode_readdir(struct xdr_stream *xdr, const struct nfs4_readdir_arg
FATTR4_WORD0_RDATTR_ERROR,
FATTR4_WORD1_MOUNTED_ON_FILEID,
};
- uint32_t dircount = readdir->count >> 1;
+ uint32_t dircount = readdir->count;
+ uint32_t maxcount = readdir->count;
__be32 *p, verf[2];
uint32_t attrlen = 0;
unsigned int i;
@@ -1618,7 +1619,6 @@ static void encode_readdir(struct xdr_stream *xdr, const struct nfs4_readdir_arg
FATTR4_WORD1_SPACE_USED|FATTR4_WORD1_TIME_ACCESS|
FATTR4_WORD1_TIME_METADATA|FATTR4_WORD1_TIME_MODIFY;
attrs[2] |= FATTR4_WORD2_SECURITY_LABEL;
- dircount >>= 1;
}
/* Use mounted_on_fileid only if the server supports it */
if (!(readdir->bitmask[1] & FATTR4_WORD1_MOUNTED_ON_FILEID))
@@ -1634,7 +1634,7 @@ static void encode_readdir(struct xdr_stream *xdr, const struct nfs4_readdir_arg
encode_nfs4_verifier(xdr, &readdir->verifier);
p = reserve_space(xdr, 12 + (attrlen << 2));
*p++ = cpu_to_be32(dircount);
- *p++ = cpu_to_be32(readdir->count);
+ *p++ = cpu_to_be32(maxcount);
*p++ = cpu_to_be32(attrlen);
for (i = 0; i < attrlen; i++)
*p++ = cpu_to_be32(attrs[i]);
--
2.35.1

2022-02-24 01:42:02

by Trond Myklebust

[permalink] [raw]
Subject: [PATCH v7 14/21] NFS: Readdirplus can't help lookup for case insensitive filesystems

From: Trond Myklebust <[email protected]>

If the filesystem is case insensitive, then readdirplus can't help with
cache misses, since it won't return case folded variants of the filename.

Signed-off-by: Trond Myklebust <[email protected]>
---
fs/nfs/dir.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index e7942fbe3f50..a9098d5a9fc8 100644
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -684,6 +684,8 @@ void nfs_readdir_record_entry_cache_miss(struct inode *dir)

static void nfs_lookup_advise_force_readdirplus(struct inode *dir)
{
+ if (nfs_server_capable(dir, NFS_CAP_CASE_INSENSITIVE))
+ return;
nfs_readdir_record_entry_cache_miss(dir);
}

--
2.35.1