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Code Issues Releases Wiki Activity

fix nfs O_DIRECT advancing iov_iter too much

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It leaves the iterator advanced by the amount of IO it has requested
instead of the amount actually transferred.  Among other things,
that confuses the hell out of generic_file_splice_read().

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2017-04-13 09:31:51 -04:00
parent 71d6ad0837
commit 85128b2be6
1 changed files with 18 additions and 9 deletions
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27
fs/nfs/direct.c
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@ -537,7 +537,7 @@ static ssize_t nfs_direct_read_schedule_iovec(struct nfs_direct_req *dreq,
if (put_dreq(dreq))
nfs_direct_complete(dreq);
return 0;
return requested_bytes;
}
/**
@ -566,7 +566,7 @@ ssize_t nfs_file_direct_read(struct kiocb *iocb, struct iov_iter *iter)
struct inode *inode = mapping->host;
struct nfs_direct_req *dreq;
struct nfs_lock_context *l_ctx;
ssize_t result = -EINVAL;
ssize_t result = -EINVAL, requested;
size_t count = iov_iter_count(iter);
nfs_add_stats(mapping->host, NFSIOS_DIRECTREADBYTES, count);
@ -600,14 +600,19 @@ ssize_t nfs_file_direct_read(struct kiocb *iocb, struct iov_iter *iter)
nfs_start_io_direct(inode);
NFS_I(inode)->read_io += count;
result = nfs_direct_read_schedule_iovec(dreq, iter, iocb->ki_pos);
requested = nfs_direct_read_schedule_iovec(dreq, iter, iocb->ki_pos);
nfs_end_io_direct(inode);
if (!result) {
if (requested > 0) {
result = nfs_direct_wait(dreq);
if (result > 0)
if (result > 0) {
requested -= result;
iocb->ki_pos += result;
}
iov_iter_revert(iter, requested);
} else {
result = requested;
}
out_release:
@ -954,7 +959,7 @@ static ssize_t nfs_direct_write_schedule_iovec(struct nfs_direct_req *dreq,
if (put_dreq(dreq))
nfs_direct_write_complete(dreq);
return 0;
return requested_bytes;
}
/**
@ -979,7 +984,7 @@ static ssize_t nfs_direct_write_schedule_iovec(struct nfs_direct_req *dreq,
*/
ssize_t nfs_file_direct_write(struct kiocb *iocb, struct iov_iter *iter)
{
ssize_t result = -EINVAL;
ssize_t result = -EINVAL, requested;
size_t count;
struct file *file = iocb->ki_filp;
struct address_space *mapping = file->f_mapping;
@ -1022,7 +1027,7 @@ ssize_t nfs_file_direct_write(struct kiocb *iocb, struct iov_iter *iter)
nfs_start_io_direct(inode);
result = nfs_direct_write_schedule_iovec(dreq, iter, pos);
requested = nfs_direct_write_schedule_iovec(dreq, iter, pos);
if (mapping->nrpages) {
invalidate_inode_pages2_range(mapping,
@ -1031,13 +1036,17 @@ ssize_t nfs_file_direct_write(struct kiocb *iocb, struct iov_iter *iter)
nfs_end_io_direct(inode);
if (!result) {
if (requested > 0) {
result = nfs_direct_wait(dreq);
if (result > 0) {
requested -= result;
iocb->ki_pos = pos + result;
/* XXX: should check the generic_write_sync retval */
generic_write_sync(iocb, result);
}
iov_iter_revert(iter, requested);
} else {
result = requested;
}
out_release:
nfs_direct_req_release(dreq);