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NFS: clean up NFS client's a_ops->direct_IO method 

The NFS client's a_ops->direct_IO method, nfs_direct_IO, is required to
be present to allow NFS files to be opened with O_DIRECT, but is never
called because the NFS client shunts reads and writes to files opened
with O_DIRECT directly to its own routines.

Gut the nfs_direct_IO function.  This eliminates the only part of the
NFS client's direct I/O path that requires support for multi-segment
iovs, allowing further simplification in subsequent patches.

Test plan:
Compile the kernel with CONFIG_NFS and CONFIG_NFS_DIRECTIO enabled.  Millions
of fsx-odirect ops.  OraSim.

Signed-off-by: Chuck Lever <cel@netapp.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
This commit is contained in:
Chuck Lever 2006-03-20 13:44:28 -05:00 committed by Trond Myklebust
parent ec06c096ed
commit b8a32e2b8b
1 changed files with 23 additions and 47 deletions
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70
fs/nfs/direct.c
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@ -78,6 +78,29 @@ struct nfs_direct_req {
};
/**
* nfs_direct_IO - NFS address space operation for direct I/O
* @rw: direction (read or write)
* @iocb: target I/O control block
* @iov: array of vectors that define I/O buffer
* @pos: offset in file to begin the operation
* @nr_segs: size of iovec array
*
* The presence of this routine in the address space ops vector means
* the NFS client supports direct I/O. However, we shunt off direct
* read and write requests before the VFS gets them, so this method
* should never be called.
*/
ssize_t nfs_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov, loff_t pos, unsigned long nr_segs)
{
struct dentry *dentry = iocb->ki_filp->f_dentry;
dprintk("NFS: nfs_direct_IO (%s) off/no(%Ld/%lu) EINVAL\n",
dentry->d_name.name, (long long) pos, nr_segs);
return -EINVAL;
}
/**
* nfs_get_user_pages - find and set up pages underlying user's buffer
* rw: direction (read or write)
@ -605,53 +628,6 @@ static ssize_t nfs_direct_write(struct inode *inode,
return tot_bytes;
}
/**
* nfs_direct_IO - NFS address space operation for direct I/O
* rw: direction (read or write)
* @iocb: target I/O control block
* @iov: array of vectors that define I/O buffer
* file_offset: offset in file to begin the operation
* nr_segs: size of iovec array
*
*/
ssize_t
nfs_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov,
loff_t file_offset, unsigned long nr_segs)
{
ssize_t result = -EINVAL;
struct file *file = iocb->ki_filp;
struct nfs_open_context *ctx;
struct dentry *dentry = file->f_dentry;
struct inode *inode = dentry->d_inode;
/*
* No support for async yet
*/
if (!is_sync_kiocb(iocb))
return result;
ctx = (struct nfs_open_context *)file->private_data;
switch (rw) {
case READ:
dprintk("NFS: direct_IO(read) (%s) off/no(%Lu/%lu)\n",
dentry->d_name.name, file_offset, nr_segs);
result = nfs_direct_read(inode, ctx, iov,
file_offset, nr_segs);
break;
case WRITE:
dprintk("NFS: direct_IO(write) (%s) off/no(%Lu/%lu)\n",
dentry->d_name.name, file_offset, nr_segs);
result = nfs_direct_write(inode, ctx, iov,
file_offset, nr_segs);
break;
default:
break;
}
return result;
}
/**
* nfs_file_direct_read - file direct read operation for NFS files
* @iocb: target I/O control block