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nfs: merge nfs_direct_read into nfs_file_direct_read 

Simple code cleanup to prepare for later fixes.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
This commit is contained in:
Christoph Hellwig 2013-11-14 08:50:31 -08:00 committed by Trond Myklebust
parent 1f90ee2746
commit 14a3ec7943
1 changed files with 49 additions and 58 deletions
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107
fs/nfs/direct.c
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@ -458,14 +458,55 @@ static ssize_t nfs_direct_read_schedule_iovec(struct nfs_direct_req *dreq,
return 0; return 0;
} }
static ssize_t nfs_direct_read(struct kiocb *iocb, const struct iovec *iov, /**
unsigned long nr_segs, loff_t pos, bool uio) * nfs_file_direct_read - file direct read operation for NFS files
* @iocb: target I/O control block
* @iov: vector of user buffers into which to read data
* @nr_segs: size of iov vector
* @pos: byte offset in file where reading starts
*
* We use this function for direct reads instead of calling
* generic_file_aio_read() in order to avoid gfar's check to see if
* the request starts before the end of the file. For that check
* to work, we must generate a GETATTR before each direct read, and
* even then there is a window between the GETATTR and the subsequent
* READ where the file size could change. Our preference is simply
* to do all reads the application wants, and the server will take
* care of managing the end of file boundary.
*
* This function also eliminates unnecessarily updating the file's
* atime locally, as the NFS server sets the file's atime, and this
* client must read the updated atime from the server back into its
* cache.
*/
ssize_t nfs_file_direct_read(struct kiocb *iocb, const struct iovec *iov,
unsigned long nr_segs, loff_t pos, bool uio)
{ {
ssize_t result = -ENOMEM; struct file *file = iocb->ki_filp;
struct inode *inode = iocb->ki_filp->f_mapping->host; struct address_space *mapping = file->f_mapping;
struct inode *inode = mapping->host;
struct nfs_direct_req *dreq; struct nfs_direct_req *dreq;
struct nfs_lock_context *l_ctx; struct nfs_lock_context *l_ctx;
ssize_t result = -EINVAL;
size_t count;
count = iov_length(iov, nr_segs);
nfs_add_stats(mapping->host, NFSIOS_DIRECTREADBYTES, count);
dfprintk(FILE, "NFS: direct read(%pD2, %zd@%Ld)\n",
file, count, (long long) pos);
result = 0;
if (!count)
goto out;
result = nfs_sync_mapping(mapping);
if (result)
goto out;
task_io_account_read(count);
result = -ENOMEM;
dreq = nfs_direct_req_alloc(); dreq = nfs_direct_req_alloc();
if (dreq == NULL) if (dreq == NULL)
goto out; goto out;
@ -484,8 +525,11 @@ static ssize_t nfs_direct_read(struct kiocb *iocb, const struct iovec *iov,
NFS_I(inode)->read_io += iov_length(iov, nr_segs); NFS_I(inode)->read_io += iov_length(iov, nr_segs);
result = nfs_direct_read_schedule_iovec(dreq, iov, nr_segs, pos, uio); result = nfs_direct_read_schedule_iovec(dreq, iov, nr_segs, pos, uio);
if (!result) if (!result) {
result = nfs_direct_wait(dreq); result = nfs_direct_wait(dreq);
if (result > 0)
iocb->ki_pos = pos + result;
}
out_release: out_release:
nfs_direct_req_release(dreq); nfs_direct_req_release(dreq);
out: out:
@ -888,59 +932,6 @@ out:
return result; return result;
} }
/**
* nfs_file_direct_read - file direct read operation for NFS files
* @iocb: target I/O control block
* @iov: vector of user buffers into which to read data
* @nr_segs: size of iov vector
* @pos: byte offset in file where reading starts
*
* We use this function for direct reads instead of calling
* generic_file_aio_read() in order to avoid gfar's check to see if
* the request starts before the end of the file. For that check
* to work, we must generate a GETATTR before each direct read, and
* even then there is a window between the GETATTR and the subsequent
* READ where the file size could change. Our preference is simply
* to do all reads the application wants, and the server will take
* care of managing the end of file boundary.
*
* This function also eliminates unnecessarily updating the file's
* atime locally, as the NFS server sets the file's atime, and this
* client must read the updated atime from the server back into its
* cache.
*/
ssize_t nfs_file_direct_read(struct kiocb *iocb, const struct iovec *iov,
unsigned long nr_segs, loff_t pos, bool uio)
{
ssize_t retval = -EINVAL;
struct file *file = iocb->ki_filp;
struct address_space *mapping = file->f_mapping;
size_t count;
count = iov_length(iov, nr_segs);
nfs_add_stats(mapping->host, NFSIOS_DIRECTREADBYTES, count);
dfprintk(FILE, "NFS: direct read(%pD2, %zd@%Ld)\n",
file, count, (long long) pos);
retval = 0;
if (!count)
goto out;
retval = nfs_sync_mapping(mapping);
if (retval)
goto out;
task_io_account_read(count);
retval = nfs_direct_read(iocb, iov, nr_segs, pos, uio);
if (retval > 0)
iocb->ki_pos = pos + retval;
out:
return retval;
}
/** /**
* nfs_file_direct_write - file direct write operation for NFS files * nfs_file_direct_write - file direct write operation for NFS files
* @iocb: target I/O control block * @iocb: target I/O control block