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994 lines
26 KiB
994 lines
26 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* linux/fs/nfs/direct.c |
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* |
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* Copyright (C) 2003 by Chuck Lever <[email protected]> |
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* |
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* High-performance uncached I/O for the Linux NFS client |
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* |
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* There are important applications whose performance or correctness |
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* depends on uncached access to file data. Database clusters |
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* (multiple copies of the same instance running on separate hosts) |
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* implement their own cache coherency protocol that subsumes file |
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* system cache protocols. Applications that process datasets |
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* considerably larger than the client's memory do not always benefit |
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* from a local cache. A streaming video server, for instance, has no |
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* need to cache the contents of a file. |
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* |
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* When an application requests uncached I/O, all read and write requests |
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* are made directly to the server; data stored or fetched via these |
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* requests is not cached in the Linux page cache. The client does not |
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* correct unaligned requests from applications. All requested bytes are |
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* held on permanent storage before a direct write system call returns to |
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* an application. |
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* |
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* Solaris implements an uncached I/O facility called directio() that |
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* is used for backups and sequential I/O to very large files. Solaris |
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* also supports uncaching whole NFS partitions with "-o forcedirectio," |
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* an undocumented mount option. |
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* |
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* Designed by Jeff Kimmel, Chuck Lever, and Trond Myklebust, with |
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* help from Andrew Morton. |
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* |
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* 18 Dec 2001 Initial implementation for 2.4 --cel |
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* 08 Jul 2002 Version for 2.4.19, with bug fixes --trondmy |
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* 08 Jun 2003 Port to 2.5 APIs --cel |
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* 31 Mar 2004 Handle direct I/O without VFS support --cel |
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* 15 Sep 2004 Parallel async reads --cel |
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* 04 May 2005 support O_DIRECT with aio --cel |
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* |
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*/ |
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|
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#include <linux/errno.h> |
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#include <linux/sched.h> |
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#include <linux/kernel.h> |
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#include <linux/file.h> |
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#include <linux/pagemap.h> |
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#include <linux/kref.h> |
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#include <linux/slab.h> |
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#include <linux/task_io_accounting_ops.h> |
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#include <linux/module.h> |
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|
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#include <linux/nfs_fs.h> |
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#include <linux/nfs_page.h> |
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#include <linux/sunrpc/clnt.h> |
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|
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#include <linux/uaccess.h> |
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#include <linux/atomic.h> |
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|
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#include "internal.h" |
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#include "iostat.h" |
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#include "pnfs.h" |
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#include "fscache.h" |
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|
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#define NFSDBG_FACILITY NFSDBG_VFS |
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|
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static struct kmem_cache *nfs_direct_cachep; |
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|
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struct nfs_direct_req { |
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struct kref kref; /* release manager */ |
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|
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/* I/O parameters */ |
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struct nfs_open_context *ctx; /* file open context info */ |
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struct nfs_lock_context *l_ctx; /* Lock context info */ |
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struct kiocb * iocb; /* controlling i/o request */ |
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struct inode * inode; /* target file of i/o */ |
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|
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/* completion state */ |
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atomic_t io_count; /* i/os we're waiting for */ |
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spinlock_t lock; /* protect completion state */ |
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|
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loff_t io_start; /* Start offset for I/O */ |
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ssize_t count, /* bytes actually processed */ |
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max_count, /* max expected count */ |
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bytes_left, /* bytes left to be sent */ |
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error; /* any reported error */ |
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struct completion completion; /* wait for i/o completion */ |
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|
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/* commit state */ |
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struct nfs_mds_commit_info mds_cinfo; /* Storage for cinfo */ |
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struct pnfs_ds_commit_info ds_cinfo; /* Storage for cinfo */ |
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struct work_struct work; |
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int flags; |
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/* for write */ |
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#define NFS_ODIRECT_DO_COMMIT (1) /* an unstable reply was received */ |
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#define NFS_ODIRECT_RESCHED_WRITES (2) /* write verification failed */ |
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/* for read */ |
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#define NFS_ODIRECT_SHOULD_DIRTY (3) /* dirty user-space page after read */ |
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#define NFS_ODIRECT_DONE INT_MAX /* write verification failed */ |
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}; |
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|
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static const struct nfs_pgio_completion_ops nfs_direct_write_completion_ops; |
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static const struct nfs_commit_completion_ops nfs_direct_commit_completion_ops; |
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static void nfs_direct_write_complete(struct nfs_direct_req *dreq); |
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static void nfs_direct_write_schedule_work(struct work_struct *work); |
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|
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static inline void get_dreq(struct nfs_direct_req *dreq) |
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{ |
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atomic_inc(&dreq->io_count); |
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} |
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|
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static inline int put_dreq(struct nfs_direct_req *dreq) |
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{ |
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return atomic_dec_and_test(&dreq->io_count); |
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} |
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|
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static void |
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nfs_direct_handle_truncated(struct nfs_direct_req *dreq, |
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const struct nfs_pgio_header *hdr, |
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ssize_t dreq_len) |
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{ |
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if (!(test_bit(NFS_IOHDR_ERROR, &hdr->flags) || |
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test_bit(NFS_IOHDR_EOF, &hdr->flags))) |
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return; |
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if (dreq->max_count >= dreq_len) { |
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dreq->max_count = dreq_len; |
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if (dreq->count > dreq_len) |
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dreq->count = dreq_len; |
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|
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if (test_bit(NFS_IOHDR_ERROR, &hdr->flags)) |
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dreq->error = hdr->error; |
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else /* Clear outstanding error if this is EOF */ |
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dreq->error = 0; |
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} |
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} |
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|
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static void |
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nfs_direct_count_bytes(struct nfs_direct_req *dreq, |
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const struct nfs_pgio_header *hdr) |
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{ |
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loff_t hdr_end = hdr->io_start + hdr->good_bytes; |
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ssize_t dreq_len = 0; |
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|
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if (hdr_end > dreq->io_start) |
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dreq_len = hdr_end - dreq->io_start; |
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nfs_direct_handle_truncated(dreq, hdr, dreq_len); |
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|
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if (dreq_len > dreq->max_count) |
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dreq_len = dreq->max_count; |
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|
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if (dreq->count < dreq_len) |
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dreq->count = dreq_len; |
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} |
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|
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/** |
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* nfs_direct_IO - NFS address space operation for direct I/O |
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* @iocb: target I/O control block |
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* @iter: I/O buffer |
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* |
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* The presence of this routine in the address space ops vector means |
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* the NFS client supports direct I/O. However, for most direct IO, we |
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* shunt off direct read and write requests before the VFS gets them, |
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* so this method is only ever called for swap. |
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*/ |
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ssize_t nfs_direct_IO(struct kiocb *iocb, struct iov_iter *iter) |
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{ |
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struct inode *inode = iocb->ki_filp->f_mapping->host; |
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|
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/* we only support swap file calling nfs_direct_IO */ |
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if (!IS_SWAPFILE(inode)) |
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return 0; |
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VM_BUG_ON(iov_iter_count(iter) != PAGE_SIZE); |
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|
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if (iov_iter_rw(iter) == READ) |
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return nfs_file_direct_read(iocb, iter); |
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return nfs_file_direct_write(iocb, iter); |
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} |
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|
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static void nfs_direct_release_pages(struct page **pages, unsigned int npages) |
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{ |
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unsigned int i; |
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for (i = 0; i < npages; i++) |
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put_page(pages[i]); |
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} |
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|
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void nfs_init_cinfo_from_dreq(struct nfs_commit_info *cinfo, |
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struct nfs_direct_req *dreq) |
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{ |
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cinfo->inode = dreq->inode; |
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cinfo->mds = &dreq->mds_cinfo; |
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cinfo->ds = &dreq->ds_cinfo; |
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cinfo->dreq = dreq; |
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cinfo->completion_ops = &nfs_direct_commit_completion_ops; |
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} |
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static inline struct nfs_direct_req *nfs_direct_req_alloc(void) |
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{ |
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struct nfs_direct_req *dreq; |
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|
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dreq = kmem_cache_zalloc(nfs_direct_cachep, GFP_KERNEL); |
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if (!dreq) |
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return NULL; |
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kref_init(&dreq->kref); |
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kref_get(&dreq->kref); |
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init_completion(&dreq->completion); |
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INIT_LIST_HEAD(&dreq->mds_cinfo.list); |
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pnfs_init_ds_commit_info(&dreq->ds_cinfo); |
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INIT_WORK(&dreq->work, nfs_direct_write_schedule_work); |
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spin_lock_init(&dreq->lock); |
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return dreq; |
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} |
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static void nfs_direct_req_free(struct kref *kref) |
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{ |
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struct nfs_direct_req *dreq = container_of(kref, struct nfs_direct_req, kref); |
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|
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pnfs_release_ds_info(&dreq->ds_cinfo, dreq->inode); |
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if (dreq->l_ctx != NULL) |
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nfs_put_lock_context(dreq->l_ctx); |
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if (dreq->ctx != NULL) |
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put_nfs_open_context(dreq->ctx); |
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kmem_cache_free(nfs_direct_cachep, dreq); |
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} |
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static void nfs_direct_req_release(struct nfs_direct_req *dreq) |
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{ |
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kref_put(&dreq->kref, nfs_direct_req_free); |
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} |
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ssize_t nfs_dreq_bytes_left(struct nfs_direct_req *dreq) |
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{ |
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return dreq->bytes_left; |
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} |
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EXPORT_SYMBOL_GPL(nfs_dreq_bytes_left); |
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|
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/* |
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* Collects and returns the final error value/byte-count. |
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*/ |
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static ssize_t nfs_direct_wait(struct nfs_direct_req *dreq) |
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{ |
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ssize_t result = -EIOCBQUEUED; |
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|
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/* Async requests don't wait here */ |
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if (dreq->iocb) |
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goto out; |
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result = wait_for_completion_killable(&dreq->completion); |
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if (!result) { |
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result = dreq->count; |
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WARN_ON_ONCE(dreq->count < 0); |
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} |
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if (!result) |
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result = dreq->error; |
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out: |
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return (ssize_t) result; |
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} |
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|
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/* |
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* Synchronous I/O uses a stack-allocated iocb. Thus we can't trust |
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* the iocb is still valid here if this is a synchronous request. |
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*/ |
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static void nfs_direct_complete(struct nfs_direct_req *dreq) |
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{ |
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struct inode *inode = dreq->inode; |
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inode_dio_end(inode); |
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if (dreq->iocb) { |
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long res = (long) dreq->error; |
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if (dreq->count != 0) { |
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res = (long) dreq->count; |
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WARN_ON_ONCE(dreq->count < 0); |
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} |
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dreq->iocb->ki_complete(dreq->iocb, res); |
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} |
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complete(&dreq->completion); |
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nfs_direct_req_release(dreq); |
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} |
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static void nfs_direct_read_completion(struct nfs_pgio_header *hdr) |
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{ |
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unsigned long bytes = 0; |
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struct nfs_direct_req *dreq = hdr->dreq; |
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spin_lock(&dreq->lock); |
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if (test_bit(NFS_IOHDR_REDO, &hdr->flags)) { |
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spin_unlock(&dreq->lock); |
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goto out_put; |
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} |
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nfs_direct_count_bytes(dreq, hdr); |
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spin_unlock(&dreq->lock); |
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while (!list_empty(&hdr->pages)) { |
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struct nfs_page *req = nfs_list_entry(hdr->pages.next); |
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struct page *page = req->wb_page; |
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|
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if (!PageCompound(page) && bytes < hdr->good_bytes && |
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(dreq->flags == NFS_ODIRECT_SHOULD_DIRTY)) |
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set_page_dirty(page); |
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bytes += req->wb_bytes; |
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nfs_list_remove_request(req); |
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nfs_release_request(req); |
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} |
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out_put: |
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if (put_dreq(dreq)) |
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nfs_direct_complete(dreq); |
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hdr->release(hdr); |
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} |
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static void nfs_read_sync_pgio_error(struct list_head *head, int error) |
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{ |
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struct nfs_page *req; |
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|
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while (!list_empty(head)) { |
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req = nfs_list_entry(head->next); |
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nfs_list_remove_request(req); |
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nfs_release_request(req); |
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} |
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} |
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static void nfs_direct_pgio_init(struct nfs_pgio_header *hdr) |
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{ |
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get_dreq(hdr->dreq); |
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} |
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static const struct nfs_pgio_completion_ops nfs_direct_read_completion_ops = { |
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.error_cleanup = nfs_read_sync_pgio_error, |
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.init_hdr = nfs_direct_pgio_init, |
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.completion = nfs_direct_read_completion, |
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}; |
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|
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/* |
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* For each rsize'd chunk of the user's buffer, dispatch an NFS READ |
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* operation. If nfs_readdata_alloc() or get_user_pages() fails, |
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* bail and stop sending more reads. Read length accounting is |
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* handled automatically by nfs_direct_read_result(). Otherwise, if |
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* no requests have been sent, just return an error. |
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*/ |
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|
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static ssize_t nfs_direct_read_schedule_iovec(struct nfs_direct_req *dreq, |
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struct iov_iter *iter, |
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loff_t pos) |
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{ |
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struct nfs_pageio_descriptor desc; |
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struct inode *inode = dreq->inode; |
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ssize_t result = -EINVAL; |
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size_t requested_bytes = 0; |
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size_t rsize = max_t(size_t, NFS_SERVER(inode)->rsize, PAGE_SIZE); |
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|
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nfs_pageio_init_read(&desc, dreq->inode, false, |
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&nfs_direct_read_completion_ops); |
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get_dreq(dreq); |
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desc.pg_dreq = dreq; |
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inode_dio_begin(inode); |
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|
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while (iov_iter_count(iter)) { |
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struct page **pagevec; |
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size_t bytes; |
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size_t pgbase; |
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unsigned npages, i; |
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|
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result = iov_iter_get_pages_alloc(iter, &pagevec, |
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rsize, &pgbase); |
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if (result < 0) |
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break; |
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bytes = result; |
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iov_iter_advance(iter, bytes); |
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npages = (result + pgbase + PAGE_SIZE - 1) / PAGE_SIZE; |
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for (i = 0; i < npages; i++) { |
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struct nfs_page *req; |
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unsigned int req_len = min_t(size_t, bytes, PAGE_SIZE - pgbase); |
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/* XXX do we need to do the eof zeroing found in async_filler? */ |
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req = nfs_create_request(dreq->ctx, pagevec[i], |
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pgbase, req_len); |
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if (IS_ERR(req)) { |
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result = PTR_ERR(req); |
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break; |
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} |
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req->wb_index = pos >> PAGE_SHIFT; |
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req->wb_offset = pos & ~PAGE_MASK; |
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if (!nfs_pageio_add_request(&desc, req)) { |
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result = desc.pg_error; |
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nfs_release_request(req); |
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break; |
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} |
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pgbase = 0; |
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bytes -= req_len; |
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requested_bytes += req_len; |
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pos += req_len; |
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dreq->bytes_left -= req_len; |
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} |
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nfs_direct_release_pages(pagevec, npages); |
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kvfree(pagevec); |
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if (result < 0) |
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break; |
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} |
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nfs_pageio_complete(&desc); |
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|
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/* |
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* If no bytes were started, return the error, and let the |
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* generic layer handle the completion. |
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*/ |
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if (requested_bytes == 0) { |
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inode_dio_end(inode); |
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nfs_direct_req_release(dreq); |
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return result < 0 ? result : -EIO; |
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} |
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|
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if (put_dreq(dreq)) |
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nfs_direct_complete(dreq); |
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return requested_bytes; |
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} |
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|
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/** |
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* nfs_file_direct_read - file direct read operation for NFS files |
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* @iocb: target I/O control block |
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* @iter: vector of user buffers into which to read data |
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* |
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* We use this function for direct reads instead of calling |
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* generic_file_aio_read() in order to avoid gfar's check to see if |
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* the request starts before the end of the file. For that check |
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* to work, we must generate a GETATTR before each direct read, and |
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* even then there is a window between the GETATTR and the subsequent |
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* READ where the file size could change. Our preference is simply |
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* to do all reads the application wants, and the server will take |
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* care of managing the end of file boundary. |
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* |
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* This function also eliminates unnecessarily updating the file's |
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* atime locally, as the NFS server sets the file's atime, and this |
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* client must read the updated atime from the server back into its |
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* cache. |
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*/ |
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ssize_t nfs_file_direct_read(struct kiocb *iocb, struct iov_iter *iter) |
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{ |
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struct file *file = iocb->ki_filp; |
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struct address_space *mapping = file->f_mapping; |
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struct inode *inode = mapping->host; |
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struct nfs_direct_req *dreq; |
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struct nfs_lock_context *l_ctx; |
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ssize_t result, requested; |
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size_t count = iov_iter_count(iter); |
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nfs_add_stats(mapping->host, NFSIOS_DIRECTREADBYTES, count); |
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|
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dfprintk(FILE, "NFS: direct read(%pD2, %zd@%Ld)\n", |
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file, count, (long long) iocb->ki_pos); |
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|
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result = 0; |
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if (!count) |
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goto out; |
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|
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task_io_account_read(count); |
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|
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result = -ENOMEM; |
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dreq = nfs_direct_req_alloc(); |
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if (dreq == NULL) |
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goto out; |
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|
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dreq->inode = inode; |
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dreq->bytes_left = dreq->max_count = count; |
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dreq->io_start = iocb->ki_pos; |
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dreq->ctx = get_nfs_open_context(nfs_file_open_context(iocb->ki_filp)); |
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l_ctx = nfs_get_lock_context(dreq->ctx); |
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if (IS_ERR(l_ctx)) { |
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result = PTR_ERR(l_ctx); |
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nfs_direct_req_release(dreq); |
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goto out_release; |
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} |
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dreq->l_ctx = l_ctx; |
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if (!is_sync_kiocb(iocb)) |
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dreq->iocb = iocb; |
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|
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if (iter_is_iovec(iter)) |
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dreq->flags = NFS_ODIRECT_SHOULD_DIRTY; |
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|
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nfs_start_io_direct(inode); |
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|
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NFS_I(inode)->read_io += count; |
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requested = nfs_direct_read_schedule_iovec(dreq, iter, iocb->ki_pos); |
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|
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nfs_end_io_direct(inode); |
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|
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if (requested > 0) { |
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result = nfs_direct_wait(dreq); |
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if (result > 0) { |
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requested -= result; |
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iocb->ki_pos += result; |
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} |
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iov_iter_revert(iter, requested); |
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} else { |
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result = requested; |
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} |
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|
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out_release: |
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nfs_direct_req_release(dreq); |
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out: |
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return result; |
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} |
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|
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static void |
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nfs_direct_join_group(struct list_head *list, struct inode *inode) |
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{ |
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struct nfs_page *req, *next; |
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|
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list_for_each_entry(req, list, wb_list) { |
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if (req->wb_head != req || req->wb_this_page == req) |
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continue; |
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for (next = req->wb_this_page; |
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next != req->wb_head; |
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next = next->wb_this_page) { |
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nfs_list_remove_request(next); |
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nfs_release_request(next); |
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} |
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nfs_join_page_group(req, inode); |
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} |
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} |
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|
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static void |
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nfs_direct_write_scan_commit_list(struct inode *inode, |
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struct list_head *list, |
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struct nfs_commit_info *cinfo) |
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{ |
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mutex_lock(&NFS_I(cinfo->inode)->commit_mutex); |
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pnfs_recover_commit_reqs(list, cinfo); |
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nfs_scan_commit_list(&cinfo->mds->list, list, cinfo, 0); |
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mutex_unlock(&NFS_I(cinfo->inode)->commit_mutex); |
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} |
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|
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static void nfs_direct_write_reschedule(struct nfs_direct_req *dreq) |
|
{ |
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struct nfs_pageio_descriptor desc; |
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struct nfs_page *req, *tmp; |
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LIST_HEAD(reqs); |
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struct nfs_commit_info cinfo; |
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LIST_HEAD(failed); |
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|
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nfs_init_cinfo_from_dreq(&cinfo, dreq); |
|
nfs_direct_write_scan_commit_list(dreq->inode, &reqs, &cinfo); |
|
|
|
nfs_direct_join_group(&reqs, dreq->inode); |
|
|
|
dreq->count = 0; |
|
dreq->max_count = 0; |
|
list_for_each_entry(req, &reqs, wb_list) |
|
dreq->max_count += req->wb_bytes; |
|
nfs_clear_pnfs_ds_commit_verifiers(&dreq->ds_cinfo); |
|
get_dreq(dreq); |
|
|
|
nfs_pageio_init_write(&desc, dreq->inode, FLUSH_STABLE, false, |
|
&nfs_direct_write_completion_ops); |
|
desc.pg_dreq = dreq; |
|
|
|
list_for_each_entry_safe(req, tmp, &reqs, wb_list) { |
|
/* Bump the transmission count */ |
|
req->wb_nio++; |
|
if (!nfs_pageio_add_request(&desc, req)) { |
|
nfs_list_move_request(req, &failed); |
|
spin_lock(&cinfo.inode->i_lock); |
|
dreq->flags = 0; |
|
if (desc.pg_error < 0) |
|
dreq->error = desc.pg_error; |
|
else |
|
dreq->error = -EIO; |
|
spin_unlock(&cinfo.inode->i_lock); |
|
} |
|
nfs_release_request(req); |
|
} |
|
nfs_pageio_complete(&desc); |
|
|
|
while (!list_empty(&failed)) { |
|
req = nfs_list_entry(failed.next); |
|
nfs_list_remove_request(req); |
|
nfs_unlock_and_release_request(req); |
|
} |
|
|
|
if (put_dreq(dreq)) |
|
nfs_direct_write_complete(dreq); |
|
} |
|
|
|
static void nfs_direct_commit_complete(struct nfs_commit_data *data) |
|
{ |
|
const struct nfs_writeverf *verf = data->res.verf; |
|
struct nfs_direct_req *dreq = data->dreq; |
|
struct nfs_commit_info cinfo; |
|
struct nfs_page *req; |
|
int status = data->task.tk_status; |
|
|
|
if (status < 0) { |
|
/* Errors in commit are fatal */ |
|
dreq->error = status; |
|
dreq->max_count = 0; |
|
dreq->count = 0; |
|
dreq->flags = NFS_ODIRECT_DONE; |
|
} else if (dreq->flags == NFS_ODIRECT_DONE) |
|
status = dreq->error; |
|
|
|
nfs_init_cinfo_from_dreq(&cinfo, dreq); |
|
|
|
while (!list_empty(&data->pages)) { |
|
req = nfs_list_entry(data->pages.next); |
|
nfs_list_remove_request(req); |
|
if (status >= 0 && !nfs_write_match_verf(verf, req)) { |
|
dreq->flags = NFS_ODIRECT_RESCHED_WRITES; |
|
/* |
|
* Despite the reboot, the write was successful, |
|
* so reset wb_nio. |
|
*/ |
|
req->wb_nio = 0; |
|
nfs_mark_request_commit(req, NULL, &cinfo, 0); |
|
} else /* Error or match */ |
|
nfs_release_request(req); |
|
nfs_unlock_and_release_request(req); |
|
} |
|
|
|
if (nfs_commit_end(cinfo.mds)) |
|
nfs_direct_write_complete(dreq); |
|
} |
|
|
|
static void nfs_direct_resched_write(struct nfs_commit_info *cinfo, |
|
struct nfs_page *req) |
|
{ |
|
struct nfs_direct_req *dreq = cinfo->dreq; |
|
|
|
spin_lock(&dreq->lock); |
|
if (dreq->flags != NFS_ODIRECT_DONE) |
|
dreq->flags = NFS_ODIRECT_RESCHED_WRITES; |
|
spin_unlock(&dreq->lock); |
|
nfs_mark_request_commit(req, NULL, cinfo, 0); |
|
} |
|
|
|
static const struct nfs_commit_completion_ops nfs_direct_commit_completion_ops = { |
|
.completion = nfs_direct_commit_complete, |
|
.resched_write = nfs_direct_resched_write, |
|
}; |
|
|
|
static void nfs_direct_commit_schedule(struct nfs_direct_req *dreq) |
|
{ |
|
int res; |
|
struct nfs_commit_info cinfo; |
|
LIST_HEAD(mds_list); |
|
|
|
nfs_init_cinfo_from_dreq(&cinfo, dreq); |
|
nfs_scan_commit(dreq->inode, &mds_list, &cinfo); |
|
res = nfs_generic_commit_list(dreq->inode, &mds_list, 0, &cinfo); |
|
if (res < 0) /* res == -ENOMEM */ |
|
nfs_direct_write_reschedule(dreq); |
|
} |
|
|
|
static void nfs_direct_write_clear_reqs(struct nfs_direct_req *dreq) |
|
{ |
|
struct nfs_commit_info cinfo; |
|
struct nfs_page *req; |
|
LIST_HEAD(reqs); |
|
|
|
nfs_init_cinfo_from_dreq(&cinfo, dreq); |
|
nfs_direct_write_scan_commit_list(dreq->inode, &reqs, &cinfo); |
|
|
|
while (!list_empty(&reqs)) { |
|
req = nfs_list_entry(reqs.next); |
|
nfs_list_remove_request(req); |
|
nfs_release_request(req); |
|
nfs_unlock_and_release_request(req); |
|
} |
|
} |
|
|
|
static void nfs_direct_write_schedule_work(struct work_struct *work) |
|
{ |
|
struct nfs_direct_req *dreq = container_of(work, struct nfs_direct_req, work); |
|
int flags = dreq->flags; |
|
|
|
dreq->flags = 0; |
|
switch (flags) { |
|
case NFS_ODIRECT_DO_COMMIT: |
|
nfs_direct_commit_schedule(dreq); |
|
break; |
|
case NFS_ODIRECT_RESCHED_WRITES: |
|
nfs_direct_write_reschedule(dreq); |
|
break; |
|
default: |
|
nfs_direct_write_clear_reqs(dreq); |
|
nfs_zap_mapping(dreq->inode, dreq->inode->i_mapping); |
|
nfs_direct_complete(dreq); |
|
} |
|
} |
|
|
|
static void nfs_direct_write_complete(struct nfs_direct_req *dreq) |
|
{ |
|
queue_work(nfsiod_workqueue, &dreq->work); /* Calls nfs_direct_write_schedule_work */ |
|
} |
|
|
|
static void nfs_direct_write_completion(struct nfs_pgio_header *hdr) |
|
{ |
|
struct nfs_direct_req *dreq = hdr->dreq; |
|
struct nfs_commit_info cinfo; |
|
struct nfs_page *req = nfs_list_entry(hdr->pages.next); |
|
int flags = NFS_ODIRECT_DONE; |
|
|
|
nfs_init_cinfo_from_dreq(&cinfo, dreq); |
|
|
|
spin_lock(&dreq->lock); |
|
if (test_bit(NFS_IOHDR_REDO, &hdr->flags)) { |
|
spin_unlock(&dreq->lock); |
|
goto out_put; |
|
} |
|
|
|
nfs_direct_count_bytes(dreq, hdr); |
|
if (hdr->good_bytes != 0 && nfs_write_need_commit(hdr)) { |
|
if (!dreq->flags) |
|
dreq->flags = NFS_ODIRECT_DO_COMMIT; |
|
flags = dreq->flags; |
|
} |
|
spin_unlock(&dreq->lock); |
|
|
|
while (!list_empty(&hdr->pages)) { |
|
|
|
req = nfs_list_entry(hdr->pages.next); |
|
nfs_list_remove_request(req); |
|
if (flags == NFS_ODIRECT_DO_COMMIT) { |
|
kref_get(&req->wb_kref); |
|
memcpy(&req->wb_verf, &hdr->verf.verifier, |
|
sizeof(req->wb_verf)); |
|
nfs_mark_request_commit(req, hdr->lseg, &cinfo, |
|
hdr->ds_commit_idx); |
|
} else if (flags == NFS_ODIRECT_RESCHED_WRITES) { |
|
kref_get(&req->wb_kref); |
|
nfs_mark_request_commit(req, NULL, &cinfo, 0); |
|
} |
|
nfs_unlock_and_release_request(req); |
|
} |
|
|
|
out_put: |
|
if (put_dreq(dreq)) |
|
nfs_direct_write_complete(dreq); |
|
hdr->release(hdr); |
|
} |
|
|
|
static void nfs_write_sync_pgio_error(struct list_head *head, int error) |
|
{ |
|
struct nfs_page *req; |
|
|
|
while (!list_empty(head)) { |
|
req = nfs_list_entry(head->next); |
|
nfs_list_remove_request(req); |
|
nfs_unlock_and_release_request(req); |
|
} |
|
} |
|
|
|
static void nfs_direct_write_reschedule_io(struct nfs_pgio_header *hdr) |
|
{ |
|
struct nfs_direct_req *dreq = hdr->dreq; |
|
|
|
spin_lock(&dreq->lock); |
|
if (dreq->error == 0) { |
|
dreq->flags = NFS_ODIRECT_RESCHED_WRITES; |
|
/* fake unstable write to let common nfs resend pages */ |
|
hdr->verf.committed = NFS_UNSTABLE; |
|
hdr->good_bytes = hdr->args.offset + hdr->args.count - |
|
hdr->io_start; |
|
} |
|
spin_unlock(&dreq->lock); |
|
} |
|
|
|
static const struct nfs_pgio_completion_ops nfs_direct_write_completion_ops = { |
|
.error_cleanup = nfs_write_sync_pgio_error, |
|
.init_hdr = nfs_direct_pgio_init, |
|
.completion = nfs_direct_write_completion, |
|
.reschedule_io = nfs_direct_write_reschedule_io, |
|
}; |
|
|
|
|
|
/* |
|
* NB: Return the value of the first error return code. Subsequent |
|
* errors after the first one are ignored. |
|
*/ |
|
/* |
|
* For each wsize'd chunk of the user's buffer, dispatch an NFS WRITE |
|
* operation. If nfs_writedata_alloc() or get_user_pages() fails, |
|
* bail and stop sending more writes. Write length accounting is |
|
* handled automatically by nfs_direct_write_result(). Otherwise, if |
|
* no requests have been sent, just return an error. |
|
*/ |
|
static ssize_t nfs_direct_write_schedule_iovec(struct nfs_direct_req *dreq, |
|
struct iov_iter *iter, |
|
loff_t pos) |
|
{ |
|
struct nfs_pageio_descriptor desc; |
|
struct inode *inode = dreq->inode; |
|
ssize_t result = 0; |
|
size_t requested_bytes = 0; |
|
size_t wsize = max_t(size_t, NFS_SERVER(inode)->wsize, PAGE_SIZE); |
|
|
|
nfs_pageio_init_write(&desc, inode, FLUSH_COND_STABLE, false, |
|
&nfs_direct_write_completion_ops); |
|
desc.pg_dreq = dreq; |
|
get_dreq(dreq); |
|
inode_dio_begin(inode); |
|
|
|
NFS_I(inode)->write_io += iov_iter_count(iter); |
|
while (iov_iter_count(iter)) { |
|
struct page **pagevec; |
|
size_t bytes; |
|
size_t pgbase; |
|
unsigned npages, i; |
|
|
|
result = iov_iter_get_pages_alloc(iter, &pagevec, |
|
wsize, &pgbase); |
|
if (result < 0) |
|
break; |
|
|
|
bytes = result; |
|
iov_iter_advance(iter, bytes); |
|
npages = (result + pgbase + PAGE_SIZE - 1) / PAGE_SIZE; |
|
for (i = 0; i < npages; i++) { |
|
struct nfs_page *req; |
|
unsigned int req_len = min_t(size_t, bytes, PAGE_SIZE - pgbase); |
|
|
|
req = nfs_create_request(dreq->ctx, pagevec[i], |
|
pgbase, req_len); |
|
if (IS_ERR(req)) { |
|
result = PTR_ERR(req); |
|
break; |
|
} |
|
|
|
if (desc.pg_error < 0) { |
|
nfs_free_request(req); |
|
result = desc.pg_error; |
|
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; |
|
} |
|
pgbase = 0; |
|
bytes -= req_len; |
|
requested_bytes += req_len; |
|
pos += req_len; |
|
dreq->bytes_left -= req_len; |
|
} |
|
nfs_direct_release_pages(pagevec, npages); |
|
kvfree(pagevec); |
|
if (result < 0) |
|
break; |
|
} |
|
nfs_pageio_complete(&desc); |
|
|
|
/* |
|
* If no bytes were started, return the error, and let the |
|
* generic layer handle the completion. |
|
*/ |
|
if (requested_bytes == 0) { |
|
inode_dio_end(inode); |
|
nfs_direct_req_release(dreq); |
|
return result < 0 ? result : -EIO; |
|
} |
|
|
|
if (put_dreq(dreq)) |
|
nfs_direct_write_complete(dreq); |
|
return requested_bytes; |
|
} |
|
|
|
/** |
|
* nfs_file_direct_write - file direct write operation for NFS files |
|
* @iocb: target I/O control block |
|
* @iter: vector of user buffers from which to write data |
|
* |
|
* We use this function for direct writes instead of calling |
|
* generic_file_aio_write() in order to avoid taking the inode |
|
* semaphore and updating the i_size. The NFS server will set |
|
* the new i_size and this client must read the updated size |
|
* back into its cache. We let the server do generic write |
|
* parameter checking and report problems. |
|
* |
|
* We eliminate local atime updates, see direct read above. |
|
* |
|
* We avoid unnecessary page cache invalidations for normal cached |
|
* readers of this file. |
|
* |
|
* 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, struct iov_iter *iter) |
|
{ |
|
ssize_t result, requested; |
|
size_t count; |
|
struct file *file = iocb->ki_filp; |
|
struct address_space *mapping = file->f_mapping; |
|
struct inode *inode = mapping->host; |
|
struct nfs_direct_req *dreq; |
|
struct nfs_lock_context *l_ctx; |
|
loff_t pos, end; |
|
|
|
dfprintk(FILE, "NFS: direct write(%pD2, %zd@%Ld)\n", |
|
file, iov_iter_count(iter), (long long) iocb->ki_pos); |
|
|
|
result = generic_write_checks(iocb, iter); |
|
if (result <= 0) |
|
return result; |
|
count = result; |
|
nfs_add_stats(mapping->host, NFSIOS_DIRECTWRITTENBYTES, count); |
|
|
|
pos = iocb->ki_pos; |
|
end = (pos + iov_iter_count(iter) - 1) >> PAGE_SHIFT; |
|
|
|
task_io_account_write(count); |
|
|
|
result = -ENOMEM; |
|
dreq = nfs_direct_req_alloc(); |
|
if (!dreq) |
|
goto out; |
|
|
|
dreq->inode = inode; |
|
dreq->bytes_left = dreq->max_count = count; |
|
dreq->io_start = pos; |
|
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)) { |
|
result = PTR_ERR(l_ctx); |
|
nfs_direct_req_release(dreq); |
|
goto out_release; |
|
} |
|
dreq->l_ctx = l_ctx; |
|
if (!is_sync_kiocb(iocb)) |
|
dreq->iocb = iocb; |
|
pnfs_init_ds_commit_info_ops(&dreq->ds_cinfo, inode); |
|
|
|
nfs_start_io_direct(inode); |
|
|
|
requested = nfs_direct_write_schedule_iovec(dreq, iter, pos); |
|
|
|
if (mapping->nrpages) { |
|
invalidate_inode_pages2_range(mapping, |
|
pos >> PAGE_SHIFT, end); |
|
} |
|
|
|
nfs_end_io_direct(inode); |
|
|
|
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; |
|
} |
|
nfs_fscache_invalidate(inode, FSCACHE_INVAL_DIO_WRITE); |
|
out_release: |
|
nfs_direct_req_release(dreq); |
|
out: |
|
return result; |
|
} |
|
|
|
/** |
|
* nfs_init_directcache - create a slab cache for nfs_direct_req structures |
|
* |
|
*/ |
|
int __init nfs_init_directcache(void) |
|
{ |
|
nfs_direct_cachep = kmem_cache_create("nfs_direct_cache", |
|
sizeof(struct nfs_direct_req), |
|
0, (SLAB_RECLAIM_ACCOUNT| |
|
SLAB_MEM_SPREAD), |
|
NULL); |
|
if (nfs_direct_cachep == NULL) |
|
return -ENOMEM; |
|
|
|
return 0; |
|
} |
|
|
|
/** |
|
* nfs_destroy_directcache - destroy the slab cache for nfs_direct_req structures |
|
* |
|
*/ |
|
void nfs_destroy_directcache(void) |
|
{ |
|
kmem_cache_destroy(nfs_direct_cachep); |
|
}
|
|
|