Commit ecfc555a authored by Chuck Lever's avatar Chuck Lever Committed by Trond Myklebust

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: default avatarChuck Lever <chuck.lever@oracle.com>
Signed-off-by: default avatarTrond Myklebust <Trond.Myklebust@netapp.com>
parent 82d101d5
......@@ -1637,30 +1637,6 @@ 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
......
......@@ -5,7 +5,7 @@
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-$(CONFIG_NFS_V3) += nfs3proc.o nfs3xdr.o
......@@ -14,5 +14,4 @@ nfs-$(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
......@@ -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, %lu@%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), %lu@%Ld)\n",
dentry->d_parent->d_name.name, dentry->d_name.name,
......
......@@ -116,13 +116,8 @@ 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);
......
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