READDIRPLUS max mount option

From: Kyle Rose
Date: Fri Mar 07 2008 - 14:48:44 EST

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I have a very specific use for an NFS mount over a WAN, and allowing for much larger expected READDIRPLUS requests actually improves performance by at least a factor of 10 by eliminating the round-trip latency that results from the application's single-threaded readdir/stat/stat/stat/... behavior. Rather than maintain a hacked kernel on my end, I'd rather the READDIRPLUS limit be a mount option. Hence, the following patch. It defaults to the old behavior (8*PAGE_SIZE), but with a properly-prepared mount binary will allow the client to specify a limit.

I'm not subscribed to the list, so please CC me in any relevant discussion.

Kyle

diff --git a/fs/nfs/client.c b/fs/nfs/client.c
index c5c0175..97cb997 100644
--- a/fs/nfs/client.c
+++ b/fs/nfs/client.c
@@ -675,6 +675,8 @@ static int nfs_init_server(struct nfs_server *server,
server->acdirmin = data->acdirmin * HZ;
server->acdirmax = data->acdirmax * HZ;

+ server->readdirplusmax = data->readdirplusmax;
+
/* Start lockd here, before we might error out */
error = nfs_start_lockd(server);
if (error < 0)
@@ -806,6 +808,7 @@ static void nfs_server_copy_userdata(struct nfs_server *target, struct nfs_serve
target->acregmax = source->acregmax;
target->acdirmin = source->acdirmin;
target->acdirmax = source->acdirmax;
+ target->readdirplusmax = source->readdirplusmax;
target->caps = source->caps;
}

@@ -1062,6 +1065,8 @@ static int nfs4_init_server(struct nfs_server *server,
server->acdirmin = data->acdirmin * HZ;
server->acdirmax = data->acdirmax * HZ;

+ server->readdirplusmax = data->readdirplusmax;
+
error = nfs_init_server_rpcclient(server, &timeparms, data->auth_flavors[0]);

error:
diff --git a/fs/nfs/inode.c b/fs/nfs/inode.c
index 966a885..644239f 100644
--- a/fs/nfs/inode.c
+++ b/fs/nfs/inode.c
@@ -234,9 +234,6 @@ nfs_init_locked(struct inode *inode, void *opaque)
return 0;
}

-/* Don't use READDIRPLUS on directories that we believe are too large */
-#define NFS_LIMIT_READDIRPLUS (8*PAGE_SIZE)
-
/*
* This is our front-end to iget that looks up inodes by file handle
* instead of inode number.
@@ -290,7 +287,7 @@ nfs_fhget(struct super_block *sb, struct nfs_fh *fh, struct nfs_fattr *fattr)
inode->i_op = NFS_SB(sb)->nfs_client->rpc_ops->dir_inode_ops;
inode->i_fop = &nfs_dir_operations;
if (nfs_server_capable(inode, NFS_CAP_READDIRPLUS)
- && fattr->size <= NFS_LIMIT_READDIRPLUS)
+ && (NFS_READDIRPLUS_MAX(inode) == 0 || fattr->size <= NFS_READDIRPLUS_MAX(inode)))
set_bit(NFS_INO_ADVISE_RDPLUS, &NFS_I(inode)->flags);
/* Deal with crossing mountpoints */
if (!nfs_fsid_equal(&NFS_SB(sb)->fsid, &fattr->fsid)) {
diff --git a/fs/nfs/internal.h b/fs/nfs/internal.h
index 9319927..91426a0 100644
--- a/fs/nfs/internal.h
+++ b/fs/nfs/internal.h
@@ -36,6 +36,7 @@ struct nfs_parsed_mount_data {
int timeo, retrans;
int acregmin, acregmax,
acdirmin, acdirmax;
+ int readdirplusmax;
int namlen;
unsigned int bsize;
unsigned int auth_flavor_len;
diff --git a/fs/nfs/nfsroot.c b/fs/nfs/nfsroot.c
index 531379d..c5a9eb5 100644
--- a/fs/nfs/nfsroot.c
+++ b/fs/nfs/nfsroot.c
@@ -119,7 +119,7 @@ static int mount_port __initdata = 0; /* Mount daemon port number */
enum {
/* Options that take integer arguments */
Opt_port, Opt_rsize, Opt_wsize, Opt_timeo, Opt_retrans, Opt_acregmin,
- Opt_acregmax, Opt_acdirmin, Opt_acdirmax,
+ Opt_acregmax, Opt_acdirmin, Opt_acdirmax, Opt_readdirplusmax,
/* Options that take no arguments */
Opt_soft, Opt_hard, Opt_intr,
Opt_nointr, Opt_posix, Opt_noposix, Opt_cto, Opt_nocto, Opt_ac,
@@ -139,6 +139,7 @@ static match_table_t __initdata tokens = {
{Opt_acregmax, "acregmax=%u"},
{Opt_acdirmin, "acdirmin=%u"},
{Opt_acdirmax, "acdirmax=%u"},
+ {Opt_readdirplusmax, "readdirplusmax=%u"},
{Opt_soft, "soft"},
{Opt_hard, "hard"},
{Opt_intr, "intr"},
@@ -221,6 +222,9 @@ static int __init root_nfs_parse(char *name, char *buf)
case Opt_acdirmax:
nfs_data.acdirmax = option;
break;
+ case Opt_readdirplusmax:
+ nfs_data.readdirplusmax = option;
+ break;
case Opt_soft:
nfs_data.flags |= NFS_MOUNT_SOFT;
break;
@@ -292,15 +296,17 @@ static int __init root_nfs_name(char *name)

/* Set some default values */
memset(&nfs_data, 0, sizeof(nfs_data));
- nfs_port = -1;
- nfs_data.version = NFS_MOUNT_VERSION;
- nfs_data.flags = NFS_MOUNT_NONLM; /* No lockd in nfs root yet */
- nfs_data.rsize = NFS_DEF_FILE_IO_SIZE;
- nfs_data.wsize = NFS_DEF_FILE_IO_SIZE;
- nfs_data.acregmin = 3;
- nfs_data.acregmax = 60;
- nfs_data.acdirmin = 30;
- nfs_data.acdirmax = 60;
+ nfs_port = -1;
+ nfs_data.version = NFS_MOUNT_VERSION;
+ nfs_data.flags = NFS_MOUNT_NONLM; /* No lockd in nfs root yet */
+ nfs_data.rsize = NFS_DEF_FILE_IO_SIZE;
+ nfs_data.wsize = NFS_DEF_FILE_IO_SIZE;
+ nfs_data.acregmin = 3;
+ nfs_data.acregmax = 60;
+ nfs_data.acdirmin = 30;
+ nfs_data.acdirmax = 60;
+ nfs_data.readdirplusmax = 8*PAGE_SIZE;
+
strcpy(buf, NFS_ROOT);

/* Process options received from the remote server */
@@ -348,6 +354,8 @@ static void __init root_nfs_print(void)
printk(KERN_NOTICE "Root-NFS: acreg (min,max) = (%d,%d), acdir (min,max) = (%d,%d)\n",
nfs_data.acregmin, nfs_data.acregmax,
nfs_data.acdirmin, nfs_data.acdirmax);
+ printk(KERN_NOTICE "Root-NFS: readdirplusmax = %d\n",
+ nfs_data.readdirplusmax);
printk(KERN_NOTICE "Root-NFS: nfsd port = %d, mountd port = %d, flags = %08x\n",
nfs_port, mount_port, nfs_data.flags);
}
diff --git a/fs/nfs/super.c b/fs/nfs/super.c
index fcf4b98..87dfdfb 100644
--- a/fs/nfs/super.c
+++ b/fs/nfs/super.c
@@ -83,6 +83,7 @@ enum {
Opt_acregmin, Opt_acregmax,
Opt_acdirmin, Opt_acdirmax,
Opt_actimeo,
+ Opt_readdirplusmax,
Opt_namelen,
Opt_mountport,
Opt_mountvers,
@@ -136,6 +137,7 @@ static match_table_t nfs_mount_option_tokens = {
{ Opt_acdirmin, "acdirmin=%u" },
{ Opt_acdirmax, "acdirmax=%u" },
{ Opt_actimeo, "actimeo=%u" },
+ { Opt_readdirplusmax, "readdirplusmax=%u" },
{ Opt_userspace, "retry=%u" },
{ Opt_namelen, "namlen=%u" },
{ Opt_mountport, "mountport=%u" },
@@ -474,6 +476,7 @@ static void nfs_show_mount_options(struct seq_file *m, struct nfs_server *nfss,
seq_printf(m, ",acdirmin=%d", nfss->acdirmin/HZ);
if (nfss->acdirmax != 60*HZ || showdefaults)
seq_printf(m, ",acdirmax=%d", nfss->acdirmax/HZ);
+ seq_printf(m, ",readdirplusmax=%d", nfss->readdirplusmax);
for (nfs_infop = nfs_info; nfs_infop->flag; nfs_infop++) {
if (nfss->flags & nfs_infop->flag)
seq_puts(m, nfs_infop->str);
@@ -851,6 +854,10 @@ static int nfs_parse_mount_options(char *raw,
mnt->acdirmin =
mnt->acdirmax = option;
break;
+ case Opt_readdirplusmax:
+ if (match_int(args, &mnt->readdirplusmax))
+ return 0;
+ break;
case Opt_namelen:
if (match_int(args, &mnt->namlen))
return 0;
@@ -1190,6 +1197,8 @@ static int nfs_validate_mount_data(void *options,
case 5:
memset(data->context, 0, sizeof(data->context));
case 6:
+ data->readdirplusmax = 8*PAGE_SIZE;
+ case 7:
if (data->flags & NFS_MOUNT_VER3)
mntfh->size = data->root.size;
else
@@ -1217,6 +1226,7 @@ static int nfs_validate_mount_data(void *options,
args->acregmax = data->acregmax;
args->acdirmin = data->acdirmin;
args->acdirmax = data->acdirmax;
+ args->readdirplusmax = data->readdirplusmax;

memcpy(&args->nfs_server.address, &data->addr,
sizeof(data->addr));
@@ -1428,6 +1438,8 @@ static int nfs_compare_mount_options(const struct super_block *s, const struct n
goto Ebusy;
if (a->acdirmax != b->acdirmax)
goto Ebusy;
+ if (a->readdirplusmax != b->readdirplusmax)
+ goto Ebusy;
if (clnt_a->cl_auth->au_flavor != clnt_b->cl_auth->au_flavor)
goto Ebusy;
return 1;
@@ -1757,6 +1769,8 @@ static int nfs4_validate_mount_data(void *options,

switch (data->version) {
case 1:
+ data->readdirplusmax = 8*PAGE_SIZE;
+ case 2:
ap = (struct sockaddr_in *)&args->nfs_server.address;
if (data->host_addrlen > sizeof(args->nfs_server.address))
goto out_no_address;
@@ -1816,6 +1830,7 @@ static int nfs4_validate_mount_data(void *options,
args->acregmax = data->acregmax;
args->acdirmin = data->acdirmin;
args->acdirmax = data->acdirmax;
+ args->readdirplusmax = data->readdirplusmax;
args->nfs_server.protocol = data->proto;

break;
diff --git a/include/linux/nfs4_mount.h b/include/linux/nfs4_mount.h
index a0dcf66..ee9c21d 100644
--- a/include/linux/nfs4_mount.h
+++ b/include/linux/nfs4_mount.h
@@ -16,7 +16,7 @@
* mount-to-kernel version compatibility. Some of these aren't used yet
* but here they are anyway.
*/
-#define NFS4_MOUNT_VERSION 1
+#define NFS4_MOUNT_VERSION 2

struct nfs_string {
unsigned int len;
@@ -53,6 +53,8 @@ struct nfs4_mount_data {
/* Pseudo-flavours to use for authentication. See RFC2623 */
int auth_flavourlen; /* 1 */
int __user *auth_flavours; /* 1 */
+
+ int readdirplusmax; /* 2 */
};

/* bits in the flags field */
diff --git a/include/linux/nfs_fs.h b/include/linux/nfs_fs.h
index a69ba80..d7401b4 100644
--- a/include/linux/nfs_fs.h
+++ b/include/linux/nfs_fs.h
@@ -274,6 +274,11 @@ static inline int nfs_server_capable(struct inode *inode, int cap)
return NFS_SERVER(inode)->caps & cap;
}

+static inline unsigned int NFS_READDIRPLUS_MAX(struct inode *inode)
+{
+ return NFS_SERVER(inode)->readdirplusmax;
+}
+
static inline int NFS_USE_READDIRPLUS(struct inode *inode)
{
return test_bit(NFS_INO_ADVISE_RDPLUS, &NFS_I(inode)->flags);
diff --git a/include/linux/nfs_fs_sb.h b/include/linux/nfs_fs_sb.h
index 3423c67..d596065 100644
--- a/include/linux/nfs_fs_sb.h
+++ b/include/linux/nfs_fs_sb.h
@@ -99,6 +99,8 @@ struct nfs_server {
unsigned int acdirmin;
unsigned int acdirmax;
unsigned int namelen;
+ unsigned int readdirplusmax; /* max believed dir size for
+ READDIRPLUS */

struct nfs_fsid fsid;
__u64 maxfilesize; /* maximum file size */
diff --git a/include/linux/nfs_mount.h b/include/linux/nfs_mount.h
index df7c6b7..686d185 100644
--- a/include/linux/nfs_mount.h
+++ b/include/linux/nfs_mount.h
@@ -20,7 +20,7 @@
* mount-to-kernel version compatibility. Some of these aren't used yet
* but here they are anyway.
*/
-#define NFS_MOUNT_VERSION 6
+#define NFS_MOUNT_VERSION 7
#define NFS_MAX_CONTEXT_LEN 256

struct nfs_mount_data {
@@ -43,6 +43,7 @@ struct nfs_mount_data {
struct nfs3_fh root; /* 4 */
int pseudoflavor; /* 5 */
char context[NFS_MAX_CONTEXT_LEN + 1]; /* 6 */
+ int readdirplusmax; /* 7 */
};

/* bits in the flags field */

Next message: Christian Kujau: "Re: WARNING: at drivers/usb/host/ehci-hcd.c:287"
Previous message: Andrea Arcangeli: "Re: [PATCH] 3/4 combine RCU with seqlock to allow mmu notifiermethods to sleep (#v9 was 1/4)"
Next in thread: Trond Myklebust: "Re: READDIRPLUS max mount option"
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