This patch implements the read_iter and write_iter file operations which allow kernel code to initiate directIO. This allows the loop device to read and write directly to the server, bypassing the page cache.
Signed-off-by: Dave Kleikamp <[email protected]> Cc: Zach Brown <[email protected]> Cc: Trond Myklebust <[email protected]> Cc: [email protected] --- fs/nfs/direct.c | 169 +++++++++++++++++++++++++++++++++---------------- fs/nfs/file.c | 48 ++++++++++---- fs/nfs/internal.h | 2 + fs/nfs/nfs4file.c | 2 + include/linux/nfs_fs.h | 6 +- 5 files changed, 155 insertions(+), 72 deletions(-) diff --git a/fs/nfs/direct.c b/fs/nfs/direct.c index 4532781..b1fda1c 100644 --- a/fs/nfs/direct.c +++ b/fs/nfs/direct.c @@ -90,6 +90,7 @@ struct nfs_direct_req { int flags; #define NFS_ODIRECT_DO_COMMIT (1) /* an unstable reply was received */ #define NFS_ODIRECT_RESCHED_WRITES (2) /* write verification failed */ +#define NFS_ODIRECT_MARK_DIRTY (4) /* mark read pages dirty */ struct nfs_writeverf verf; /* unstable write verifier */ }; @@ -131,15 +132,13 @@ ssize_t nfs_direct_IO(int rw, struct kiocb *iocb, struct iov_iter *iter, return -EINVAL; #else - const struct iovec *iov = iov_iter_iovec(iter); - VM_BUG_ON(iocb->ki_left != PAGE_SIZE); VM_BUG_ON(iocb->ki_nbytes != PAGE_SIZE); if (rw == READ || rw == KERNEL_READ) - return nfs_file_direct_read(iocb, iov, iter->nr_segs, pos, + return nfs_file_direct_read(iocb, iter, pos, rw == READ ? true : false); - return nfs_file_direct_write(iocb, iov, iter->nr_segs, pos, + return nfs_file_direct_write(iocb, iter, pos, rw == WRITE ? true : false); #endif /* CONFIG_NFS_SWAP */ } @@ -277,7 +276,8 @@ static void nfs_direct_read_completion(struct nfs_pgio_header *hdr) hdr->good_bytes & ~PAGE_MASK, PAGE_SIZE); } - if (!PageCompound(page)) { + if ((dreq->flags & NFS_ODIRECT_MARK_DIRTY) && + !PageCompound(page)) { if (test_bit(NFS_IOHDR_ERROR, &hdr->flags)) { if (bytes < hdr->good_bytes) set_page_dirty(page); @@ -414,10 +414,9 @@ static ssize_t nfs_direct_read_schedule_segment(struct nfs_pageio_descriptor *de return result < 0 ? (ssize_t) result : -EFAULT; } -static ssize_t nfs_direct_read_schedule_iovec(struct nfs_direct_req *dreq, - const struct iovec *iov, - unsigned long nr_segs, - loff_t pos, bool uio) +static ssize_t nfs_direct_read_schedule(struct nfs_direct_req *dreq, + struct iov_iter *iter, loff_t pos, + bool uio) { struct nfs_pageio_descriptor desc; ssize_t result = -EINVAL; @@ -429,16 +428,47 @@ static ssize_t nfs_direct_read_schedule_iovec(struct nfs_direct_req *dreq, get_dreq(dreq); desc.pg_dreq = dreq; - for (seg = 0; seg < nr_segs; seg++) { - const struct iovec *vec = &iov[seg]; - result = nfs_direct_read_schedule_segment(&desc, vec, pos, uio); - if (result < 0) - break; - requested_bytes += result; - if ((size_t)result < vec->iov_len) - break; - pos += vec->iov_len; - } + if (iov_iter_has_iovec(iter)) { + const struct iovec *iov = iov_iter_iovec(iter); + if (uio) + dreq->flags = NFS_ODIRECT_MARK_DIRTY; + for (seg = 0; seg < iter->nr_segs; seg++) { + const struct iovec *vec = &iov[seg]; + result = nfs_direct_read_schedule_segment(&desc, vec, + pos, uio); + if (result < 0) + break; + requested_bytes += result; + if ((size_t)result < vec->iov_len) + break; + pos += vec->iov_len; + } + } else if (iov_iter_has_bvec(iter)) { + struct nfs_open_context *ctx = dreq->ctx; + struct inode *inode = ctx->dentry->d_inode; + struct bio_vec *bvec = iov_iter_bvec(iter); + for (seg = 0; seg < iter->nr_segs; seg++) { + struct nfs_page *req; + unsigned int req_len = bvec[seg].bv_len; + req = nfs_create_request(ctx, inode, + bvec[seg].bv_page, + bvec[seg].bv_offset, req_len); + if (IS_ERR(req)) { + result = PTR_ERR(req); + break; + } + req->wb_index = pos >> PAGE_SHIFT; + req->wb_offset = pos & ~PAGE_MASK; + if (!nfs_pageio_add_request(&desc, req)) { + result = desc.pg_error; + nfs_release_request(req); + break; + } + requested_bytes += req_len; + pos += req_len; + } + } else + BUG(); nfs_pageio_complete(&desc); @@ -456,8 +486,8 @@ static ssize_t nfs_direct_read_schedule_iovec(struct nfs_direct_req *dreq, return 0; } -static ssize_t nfs_direct_read(struct kiocb *iocb, const struct iovec *iov, - unsigned long nr_segs, loff_t pos, bool uio) +static ssize_t nfs_direct_read(struct kiocb *iocb, struct iov_iter *iter, + loff_t pos, bool uio) { ssize_t result = -ENOMEM; struct inode *inode = iocb->ki_filp->f_mapping->host; @@ -469,7 +499,7 @@ static ssize_t nfs_direct_read(struct kiocb *iocb, const struct iovec *iov, goto out; dreq->inode = inode; - dreq->bytes_left = iov_length(iov, nr_segs); + dreq->bytes_left = iov_iter_count(iter); dreq->ctx = get_nfs_open_context(nfs_file_open_context(iocb->ki_filp)); l_ctx = nfs_get_lock_context(dreq->ctx); if (IS_ERR(l_ctx)) { @@ -480,8 +510,8 @@ static ssize_t nfs_direct_read(struct kiocb *iocb, const struct iovec *iov, if (!is_sync_kiocb(iocb)) dreq->iocb = iocb; - NFS_I(inode)->read_io += iov_length(iov, nr_segs); - result = nfs_direct_read_schedule_iovec(dreq, iov, nr_segs, pos, uio); + NFS_I(inode)->read_io += iov_iter_count(iter); + result = nfs_direct_read_schedule(dreq, iter, pos, uio); if (!result) result = nfs_direct_wait(dreq); out_release: @@ -815,10 +845,9 @@ static const struct nfs_pgio_completion_ops nfs_direct_write_completion_ops = { .completion = nfs_direct_write_completion, }; -static ssize_t nfs_direct_write_schedule_iovec(struct nfs_direct_req *dreq, - const struct iovec *iov, - unsigned long nr_segs, - loff_t pos, bool uio) +static ssize_t nfs_direct_write_schedule(struct nfs_direct_req *dreq, + struct iov_iter *iter, loff_t pos, + bool uio) { struct nfs_pageio_descriptor desc; struct inode *inode = dreq->inode; @@ -832,17 +861,48 @@ static ssize_t nfs_direct_write_schedule_iovec(struct nfs_direct_req *dreq, get_dreq(dreq); atomic_inc(&inode->i_dio_count); - NFS_I(dreq->inode)->write_io += iov_length(iov, nr_segs); - for (seg = 0; seg < nr_segs; seg++) { - const struct iovec *vec = &iov[seg]; - result = nfs_direct_write_schedule_segment(&desc, vec, pos, uio); - if (result < 0) - break; - requested_bytes += result; - if ((size_t)result < vec->iov_len) - break; - pos += vec->iov_len; - } + NFS_I(dreq->inode)->write_io += iov_iter_count(iter); + + if (iov_iter_has_iovec(iter)) { + const struct iovec *iov = iov_iter_iovec(iter); + for (seg = 0; seg < iter->nr_segs; seg++) { + const struct iovec *vec = &iov[seg]; + result = nfs_direct_write_schedule_segment(&desc, vec, + pos, uio); + if (result < 0) + break; + requested_bytes += result; + if ((size_t)result < vec->iov_len) + break; + pos += vec->iov_len; + } + } else if (iov_iter_has_bvec(iter)) { + struct nfs_open_context *ctx = dreq->ctx; + struct bio_vec *bvec = iov_iter_bvec(iter); + for (seg = 0; seg < iter->nr_segs; seg++) { + struct nfs_page *req; + unsigned int req_len = bvec[seg].bv_len; + + req = nfs_create_request(ctx, inode, bvec[seg].bv_page, + bvec[seg].bv_offset, req_len); + if (IS_ERR(req)) { + result = PTR_ERR(req); + break; + } + nfs_lock_request(req); + req->wb_index = pos >> PAGE_SHIFT; + req->wb_offset = pos & ~PAGE_MASK; + if (!nfs_pageio_add_request(&desc, req)) { + result = desc.pg_error; + nfs_unlock_and_release_request(req); + break; + } + requested_bytes += req_len; + pos += req_len; + } + } else + BUG(); + nfs_pageio_complete(&desc); /* @@ -860,9 +920,8 @@ static ssize_t nfs_direct_write_schedule_iovec(struct nfs_direct_req *dreq, return 0; } -static ssize_t nfs_direct_write(struct kiocb *iocb, const struct iovec *iov, - unsigned long nr_segs, loff_t pos, - size_t count, bool uio) +static ssize_t nfs_direct_write(struct kiocb *iocb, struct iov_iter *iter, + loff_t pos, bool uio) { ssize_t result = -ENOMEM; struct inode *inode = iocb->ki_filp->f_mapping->host; @@ -874,7 +933,7 @@ static ssize_t nfs_direct_write(struct kiocb *iocb, const struct iovec *iov, goto out; dreq->inode = inode; - dreq->bytes_left = count; + dreq->bytes_left = iov_iter_count(iter); dreq->ctx = get_nfs_open_context(nfs_file_open_context(iocb->ki_filp)); l_ctx = nfs_get_lock_context(dreq->ctx); if (IS_ERR(l_ctx)) { @@ -885,7 +944,7 @@ static ssize_t nfs_direct_write(struct kiocb *iocb, const struct iovec *iov, if (!is_sync_kiocb(iocb)) dreq->iocb = iocb; - result = nfs_direct_write_schedule_iovec(dreq, iov, nr_segs, pos, uio); + result = nfs_direct_write_schedule(dreq, iter, pos, uio); if (!result) result = nfs_direct_wait(dreq); out_release: @@ -897,8 +956,7 @@ out: /** * 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 + * @iter: vector of buffers into which to read data * @pos: byte offset in file where reading starts * * We use this function for direct reads instead of calling @@ -915,15 +973,15 @@ out: * 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 nfs_file_direct_read(struct kiocb *iocb, struct iov_iter *iter, + 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); + count = iov_iter_count(iter); nfs_add_stats(mapping->host, NFSIOS_DIRECTREADBYTES, count); dfprintk(FILE, "NFS: direct read(%s/%s, %zd@%Ld)\n", @@ -941,7 +999,7 @@ ssize_t nfs_file_direct_read(struct kiocb *iocb, const struct iovec *iov, task_io_account_read(count); - retval = nfs_direct_read(iocb, iov, nr_segs, pos, uio); + retval = nfs_direct_read(iocb, iter, pos, uio); if (retval > 0) iocb->ki_pos = pos + retval; @@ -952,8 +1010,7 @@ out: /** * nfs_file_direct_write - file direct write operation for NFS files * @iocb: target I/O control block - * @iov: vector of user buffers from which to write data - * @nr_segs: size of iov vector + * @iter: vector of buffers from which to write data * @pos: byte offset in file where writing starts * * We use this function for direct writes instead of calling @@ -971,15 +1028,15 @@ out: * Note that O_APPEND is not supported for NFS direct writes, as there * is no atomic O_APPEND write facility in the NFS protocol. */ -ssize_t nfs_file_direct_write(struct kiocb *iocb, const struct iovec *iov, - unsigned long nr_segs, loff_t pos, bool uio) +ssize_t nfs_file_direct_write(struct kiocb *iocb, struct iov_iter *iter, + 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); + count = iov_iter_count(iter); nfs_add_stats(mapping->host, NFSIOS_DIRECTWRITTENBYTES, count); dfprintk(FILE, "NFS: direct write(%s/%s, %zd@%Ld)\n", @@ -1004,7 +1061,7 @@ ssize_t nfs_file_direct_write(struct kiocb *iocb, const struct iovec *iov, task_io_account_write(count); - retval = nfs_direct_write(iocb, iov, nr_segs, pos, count, uio); + retval = nfs_direct_write(iocb, iter, pos, uio); if (retval > 0) { struct inode *inode = mapping->host; diff --git a/fs/nfs/file.c b/fs/nfs/file.c index 582bb88..b4bf6ef 100644 --- a/fs/nfs/file.c +++ b/fs/nfs/file.c @@ -172,28 +172,39 @@ nfs_file_flush(struct file *file, fl_owner_t id) EXPORT_SYMBOL_GPL(nfs_file_flush); ssize_t -nfs_file_read(struct kiocb *iocb, const struct iovec *iov, - unsigned long nr_segs, loff_t pos) +nfs_file_read_iter(struct kiocb *iocb, struct iov_iter *iter, loff_t pos) { struct dentry * dentry = iocb->ki_filp->f_path.dentry; struct inode * inode = dentry->d_inode; ssize_t result; if (iocb->ki_filp->f_flags & O_DIRECT) - return nfs_file_direct_read(iocb, iov, nr_segs, pos, true); + return nfs_file_direct_read(iocb, iter, pos, true); - dprintk("NFS: read(%s/%s, %lu@%lu)\n", + dprintk("NFS: read_iter(%s/%s, %lu@%lu)\n", dentry->d_parent->d_name.name, dentry->d_name.name, - (unsigned long) iov_length(iov, nr_segs), (unsigned long) pos); + (unsigned long) iov_iter_count(iter), (unsigned long) pos); result = nfs_revalidate_mapping(inode, iocb->ki_filp->f_mapping); if (!result) { - result = generic_file_aio_read(iocb, iov, nr_segs, pos); + result = generic_file_read_iter(iocb, iter, pos); if (result > 0) nfs_add_stats(inode, NFSIOS_NORMALREADBYTES, result); } return result; } +EXPORT_SYMBOL_GPL(nfs_file_read_iter); + +ssize_t +nfs_file_read(struct kiocb *iocb, const struct iovec *iov, + unsigned long nr_segs, loff_t pos) +{ + struct iov_iter iter; + + iov_iter_init(&iter, iov, nr_segs, iov_length(iov, nr_segs), 0); + + return nfs_file_read_iter(iocb, &iter, pos); +} EXPORT_SYMBOL_GPL(nfs_file_read); ssize_t @@ -610,19 +621,19 @@ static int nfs_need_sync_write(struct file *filp, struct inode *inode) return 0; } -ssize_t nfs_file_write(struct kiocb *iocb, const struct iovec *iov, - unsigned long nr_segs, loff_t pos) +ssize_t nfs_file_write_iter(struct kiocb *iocb, struct iov_iter *iter, + loff_t pos) { struct dentry * dentry = iocb->ki_filp->f_path.dentry; struct inode * inode = dentry->d_inode; unsigned long written = 0; ssize_t result; - size_t count = iov_length(iov, nr_segs); + size_t count = iov_iter_count(iter); if (iocb->ki_filp->f_flags & O_DIRECT) - return nfs_file_direct_write(iocb, iov, nr_segs, pos, true); + return nfs_file_direct_write(iocb, iter, pos, true); - dprintk("NFS: write(%s/%s, %lu@%Ld)\n", + dprintk("NFS: write_iter(%s/%s, %lu@%lld)\n", dentry->d_parent->d_name.name, dentry->d_name.name, (unsigned long) count, (long long) pos); @@ -642,7 +653,7 @@ ssize_t nfs_file_write(struct kiocb *iocb, const struct iovec *iov, if (!count) goto out; - result = generic_file_aio_write(iocb, iov, nr_segs, pos); + result = generic_file_write_iter(iocb, iter, pos); if (result > 0) written = result; @@ -661,6 +672,17 @@ out_swapfile: printk(KERN_INFO "NFS: attempt to write to active swap file!\n"); goto out; } +EXPORT_SYMBOL_GPL(nfs_file_write_iter); + +ssize_t nfs_file_write(struct kiocb *iocb, const struct iovec *iov, + unsigned long nr_segs, loff_t pos) +{ + struct iov_iter iter; + + iov_iter_init(&iter, iov, nr_segs, iov_length(iov, nr_segs), 0); + + return nfs_file_write_iter(iocb, &iter, pos); +} EXPORT_SYMBOL_GPL(nfs_file_write); ssize_t nfs_file_splice_write(struct pipe_inode_info *pipe, @@ -914,6 +936,8 @@ const struct file_operations nfs_file_operations = { .write = do_sync_write, .aio_read = nfs_file_read, .aio_write = nfs_file_write, + .read_iter = nfs_file_read_iter, + .write_iter = nfs_file_write_iter, .mmap = nfs_file_mmap, .open = nfs_file_open, .flush = nfs_file_flush, diff --git a/fs/nfs/internal.h b/fs/nfs/internal.h index 59b133c..8db3b11 100644 --- a/fs/nfs/internal.h +++ b/fs/nfs/internal.h @@ -302,10 +302,12 @@ int nfs_file_fsync_commit(struct file *, loff_t, loff_t, int); loff_t nfs_file_llseek(struct file *, loff_t, int); int nfs_file_flush(struct file *, fl_owner_t); ssize_t nfs_file_read(struct kiocb *, const struct iovec *, unsigned long, loff_t); +ssize_t nfs_file_read_iter(struct kiocb *, struct iov_iter *, loff_t); ssize_t nfs_file_splice_read(struct file *, loff_t *, struct pipe_inode_info *, size_t, unsigned int); int nfs_file_mmap(struct file *, struct vm_area_struct *); ssize_t nfs_file_write(struct kiocb *, const struct iovec *, unsigned long, loff_t); +ssize_t nfs_file_write_iter(struct kiocb *, struct iov_iter *, loff_t); int nfs_file_release(struct inode *, struct file *); int nfs_lock(struct file *, int, struct file_lock *); int nfs_flock(struct file *, int, struct file_lock *); diff --git a/fs/nfs/nfs4file.c b/fs/nfs/nfs4file.c index afddd66..195188e 100644 --- a/fs/nfs/nfs4file.c +++ b/fs/nfs/nfs4file.c @@ -123,6 +123,8 @@ const struct file_operations nfs4_file_operations = { .write = do_sync_write, .aio_read = nfs_file_read, .aio_write = nfs_file_write, + .read_iter = nfs_file_read_iter, + .write_iter = nfs_file_write_iter, .mmap = nfs_file_mmap, .open = nfs4_file_open, .flush = nfs_file_flush, diff --git a/include/linux/nfs_fs.h b/include/linux/nfs_fs.h index 4913e3c..9f8e8a9 100644 --- a/include/linux/nfs_fs.h +++ b/include/linux/nfs_fs.h @@ -445,11 +445,9 @@ extern int nfs3_removexattr (struct dentry *, const char *name); * linux/fs/nfs/direct.c */ extern ssize_t nfs_direct_IO(int, struct kiocb *, struct iov_iter *, loff_t); -extern ssize_t nfs_file_direct_read(struct kiocb *iocb, - const struct iovec *iov, unsigned long nr_segs, +extern ssize_t nfs_file_direct_read(struct kiocb *iocb, struct iov_iter *iter, loff_t pos, bool uio); -extern ssize_t nfs_file_direct_write(struct kiocb *iocb, - const struct iovec *iov, unsigned long nr_segs, +extern ssize_t nfs_file_direct_write(struct kiocb *iocb, struct iov_iter *iter, loff_t pos, bool uio); /* -- 1.7.12.3 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
