2008-02-14 20:58:07

by Chuck Lever III

[permalink] [raw]
Subject: [PATCH 1/8] NFS: Always enable NFS direct I/O

Since O_DIRECT is a standard feature that is enabled in most distros,
eliminate the CONFIG_NFS_DIRECTIO build option, and change the
fs/nfs/Makefile to always build in the NFS direct I/O engine.

Signed-off-by: Chuck Lever <[email protected]>
---

fs/Kconfig | 24 ------------------------
fs/nfs/Makefile | 3 +--
fs/nfs/file.c | 6 ------
fs/nfs/internal.h | 5 -----
4 files changed, 1 insertions(+), 37 deletions(-)

diff --git a/fs/Kconfig b/fs/Kconfig
index 1704e31..63b02d9 100644
--- a/fs/Kconfig
+++ b/fs/Kconfig
@@ -1638,30 +1638,6 @@ config NFS_V4

If unsure, say N.

-config NFS_DIRECTIO
- bool "Allow direct I/O on NFS files"
- depends on NFS_FS
- help
- This option enables applications to perform uncached I/O on files
- in NFS file systems using the O_DIRECT open() flag. When O_DIRECT
- is set for a file, its data is not cached in the system's page
- cache. Data is moved to and from user-level application buffers
- directly. Unlike local disk-based file systems, NFS O_DIRECT has
- no alignment restrictions.
-
- Unless your program is designed to use O_DIRECT properly, you are
- much better off allowing the NFS client to manage data caching for
- you. Misusing O_DIRECT can cause poor server performance or network
- storms. This kernel build option defaults OFF to avoid exposing
- system administrators unwittingly to a potentially hazardous
- feature.
-
- For more details on NFS O_DIRECT, see fs/nfs/direct.c.
-
- If unsure, say N. This reduces the size of the NFS client, and
- causes open() to return EINVAL if a file residing in NFS is
- opened with the O_DIRECT flag.
-
config NFSD
tristate "NFS server support"
depends on INET
diff --git a/fs/nfs/Makefile b/fs/nfs/Makefile
index f54c4d7..344bccb 100644
--- a/fs/nfs/Makefile
+++ b/fs/nfs/Makefile
@@ -8,7 +8,7 @@ EXTRA_CFLAGS = -W -Wall -Wextra -Wsign-compare \
obj-$(CONFIG_NFS_FS) += nfs.o

nfs-y := client.o dir.o file.o getroot.o inode.o super.o nfs2xdr.o \
- pagelist.o proc.o read.o symlink.o unlink.o \
+ direct.o pagelist.o proc.o read.o symlink.o unlink.o \
write.o namespace.o mount_clnt.o
nfs-$(CONFIG_ROOT_NFS) += nfsroot.o
nfs-$(CONFIG_NFS_V3) += nfs3proc.o nfs3xdr.o
@@ -17,5 +17,4 @@ nfs-$(CONFIG_NFS_V4) += nfs4proc.o nfs4xdr.o nfs4state.o nfs4renewd.o \
delegation.o idmap.o \
callback.o callback_xdr.o callback_proc.o \
nfs4namespace.o
-nfs-$(CONFIG_NFS_DIRECTIO) += direct.o
nfs-$(CONFIG_SYSCTL) += sysctl.o
diff --git a/fs/nfs/file.c b/fs/nfs/file.c
index ef57a5a..10e8b80 100644
--- a/fs/nfs/file.c
+++ b/fs/nfs/file.c
@@ -234,10 +234,8 @@ nfs_file_read(struct kiocb *iocb, const struct iovec *iov,
ssize_t result;
size_t count = iov_length(iov, nr_segs);

-#ifdef CONFIG_NFS_DIRECTIO
if (iocb->ki_filp->f_flags & O_DIRECT)
return nfs_file_direct_read(iocb, iov, nr_segs, pos);
-#endif

dfprintk(VFS, "nfs: read(%s/%s, %[email protected]%lu)\n",
dentry->d_parent->d_name.name, dentry->d_name.name,
@@ -383,9 +381,7 @@ const struct address_space_operations nfs_file_aops = {
.write_end = nfs_write_end,
.invalidatepage = nfs_invalidate_page,
.releasepage = nfs_release_page,
-#ifdef CONFIG_NFS_DIRECTIO
.direct_IO = nfs_direct_IO,
-#endif
.launder_page = nfs_launder_page,
};

@@ -443,10 +439,8 @@ static ssize_t nfs_file_write(struct kiocb *iocb, const struct iovec *iov,
ssize_t result;
size_t count = iov_length(iov, nr_segs);

-#ifdef CONFIG_NFS_DIRECTIO
if (iocb->ki_filp->f_flags & O_DIRECT)
return nfs_file_direct_write(iocb, iov, nr_segs, pos);
-#endif

dfprintk(VFS, "nfs: write(%s/%s(%ld), %[email protected]%Ld)\n",
dentry->d_parent->d_name.name, dentry->d_name.name,
diff --git a/fs/nfs/internal.h b/fs/nfs/internal.h
index fbe5ba4..13f43d6 100644
--- a/fs/nfs/internal.h
+++ b/fs/nfs/internal.h
@@ -113,13 +113,8 @@ extern void nfs_destroy_readpagecache(void);
extern int __init nfs_init_writepagecache(void);
extern void nfs_destroy_writepagecache(void);

-#ifdef CONFIG_NFS_DIRECTIO
extern int __init nfs_init_directcache(void);
extern void nfs_destroy_directcache(void);
-#else
-#define nfs_init_directcache() (0)
-#define nfs_destroy_directcache() do {} while(0)
-#endif

/* nfs2xdr.c */
extern int nfs_stat_to_errno(int);