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Commit 82f2e547 authored by Bryan Schumaker's avatar Bryan Schumaker Committed by Trond Myklebust
Browse files

NFS: Readdir plus in v4 



By requsting more attributes during a readdir, we can mimic the readdir plus
operation that was in NFSv3.

To test, I ran the command `ls -lU --color=none` on directories with various
numbers of files.  Without readdir plus, I see this:

n files |    100    |   1,000   |  10,000   |  100,000  | 1,000,000
--------+-----------+-----------+-----------+-----------+----------
real    | 0m00.153s | 0m00.589s | 0m05.601s | 0m56.691s | 9m59.128s
user    | 0m00.007s | 0m00.007s | 0m00.077s | 0m00.703s | 0m06.800s
sys     | 0m00.010s | 0m00.070s | 0m00.633s | 0m06.423s | 1m10.005s
access  | 3         | 1         | 1         | 4         | 31
getattr | 2         | 1         | 1         | 1         | 1
lookup  | 104       | 1,003     | 10,003    | 100,003   | 1,000,003
readdir | 2         | 16        | 158       | 1,575     | 15,749
total   | 111       | 1,021     | 10,163    | 101,583   | 1,015,784

With readdir plus enabled, I see this:

n files |    100    |   1,000   |  10,000   |  100,000  | 1,000,000
--------+-----------+-----------+-----------+-----------+----------
real    | 0m00.115s | 0m00.206s | 0m01.079s | 0m12.521s | 2m07.528s
user    | 0m00.003s | 0m00.003s | 0m00.040s | 0m00.290s | 0m03.296s
sys     | 0m00.007s | 0m00.020s | 0m00.120s | 0m01.357s | 0m17.556s
access  | 3         | 1         | 1         | 1         | 7
getattr | 2         | 1         | 1         | 1         | 1
lookup  | 4         | 3         | 3         | 3         | 3
readdir | 6         | 62        | 630       | 6,300     | 62,993
total   | 15        | 67        | 635       | 6,305     | 63,004

Readdir plus disabled has about a 16x increase in the number of rpc calls and
is 4 - 5 times slower on large directories.

Signed-off-by: default avatarBryan Schumaker <bjschuma@netapp.com>
Signed-off-by: default avatarTrond Myklebust <Trond.Myklebust@netapp.com>
parent ae42c70a

fs/nfs/client.c

+3 −2
Original line number Diff line number Diff line
@@ -1358,8 +1358,9 @@ static int nfs4_init_server(struct nfs_server *server, 


	/* Initialise the client representation from the mount data */

	server->flags = data->flags;

	server->caps |= NFS_CAP_ATOMIC_OPEN|NFS_CAP_CHANGE_ATTR|

		NFS_CAP_POSIX_LOCK;

	server->caps |= NFS_CAP_ATOMIC_OPEN|NFS_CAP_CHANGE_ATTR|NFS_CAP_POSIX_LOCK;

	if (!(data->flags & NFS_MOUNT_NORDIRPLUS))

			server->caps |= NFS_CAP_READDIRPLUS;

	server->options = data->options;



	/* Get a client record */

fs/nfs/dir.c

+2 −2
Original line number Diff line number Diff line
@@ -172,7 +172,7 @@ struct nfs_cache_array { 


#define MAX_READDIR_ARRAY ((PAGE_SIZE - sizeof(struct nfs_cache_array)) / sizeof(struct nfs_cache_array_entry))



typedef __be32 * (*decode_dirent_t)(struct xdr_stream *, struct nfs_entry *, int);

typedef __be32 * (*decode_dirent_t)(struct xdr_stream *, struct nfs_entry *, struct nfs_server *, int);

typedef struct {

	struct file	*file;

	struct page	*page;
@@ -360,7 +360,7 @@ int nfs_readdir_xdr_filler(struct page **pages, nfs_readdir_descriptor_t *desc, 
static

int xdr_decode(nfs_readdir_descriptor_t *desc, struct nfs_entry *entry, struct xdr_stream *stream)

{

	__be32 *p = desc->decode(stream, entry, desc->plus);

	__be32 *p = desc->decode(stream, entry, NFS_SERVER(desc->file->f_path.dentry->d_inode), desc->plus);

	if (IS_ERR(p))

		return PTR_ERR(p);

fs/nfs/internal.h

+3 −3
Original line number Diff line number Diff line
@@ -187,15 +187,15 @@ extern void nfs_destroy_directcache(void); 
/* nfs2xdr.c */

extern int nfs_stat_to_errno(int);

extern struct rpc_procinfo nfs_procedures[];

extern __be32 *nfs_decode_dirent(struct xdr_stream *, struct nfs_entry *, int);

extern __be32 *nfs_decode_dirent(struct xdr_stream *, struct nfs_entry *, struct nfs_server *, int);



/* nfs3xdr.c */

extern struct rpc_procinfo nfs3_procedures[];

extern __be32 *nfs3_decode_dirent(struct xdr_stream *, struct nfs_entry *, int);

extern __be32 *nfs3_decode_dirent(struct xdr_stream *, struct nfs_entry *, struct nfs_server *, int);



/* nfs4xdr.c */

#ifdef CONFIG_NFS_V4

extern __be32 *nfs4_decode_dirent(struct xdr_stream *, struct nfs_entry *entry, int plus);

extern __be32 *nfs4_decode_dirent(struct xdr_stream *, struct nfs_entry *, struct nfs_server *, int);

#endif

#ifdef CONFIG_NFS_V4_1

extern const u32 nfs41_maxread_overhead;

fs/nfs/nfs2xdr.c

+1 −1
Original line number Diff line number Diff line
@@ -454,7 +454,7 @@ static void print_overflow_msg(const char *func, const struct xdr_stream *xdr) 
}



__be32 *

nfs_decode_dirent(struct xdr_stream *xdr, struct nfs_entry *entry, int plus)

nfs_decode_dirent(struct xdr_stream *xdr, struct nfs_entry *entry, struct nfs_server *server, int plus)

{

	__be32 *p;

	p = xdr_inline_decode(xdr, 4);

fs/nfs/nfs3xdr.c

+1 −1
Original line number Diff line number Diff line
@@ -590,7 +590,7 @@ nfs3_xdr_readdirres(struct rpc_rqst *req, __be32 *p, struct nfs3_readdirres *res 
}



__be32 *

nfs3_decode_dirent(struct xdr_stream *xdr, struct nfs_entry *entry, int plus)

nfs3_decode_dirent(struct xdr_stream *xdr, struct nfs_entry *entry, struct nfs_server *server, int plus)

{

	__be32 *p;

	struct nfs_entry old = *entry;