--- /dev/null
+/*
+ * linux/fs/nfs/file.c
+ *
+ * Copyright (C) 1992 Rick Sladkey
+ *
+ * Changes Copyright (C) 1994 by Florian La Roche
+ * - Do not copy data too often around in the kernel.
+ * - In nfs_file_read the return value of kmalloc wasn't checked.
+ * - Put in a better version of read look-ahead buffering. Original idea
+ * and implementation by Wai S Kok elekokws@ee.nus.sg.
+ *
+ * Expire cache on write to a file by Wai S Kok (Oct 1994).
+ *
+ * Total rewrite of read side for new NFS buffer cache.. Linus.
+ *
+ * nfs regular file handling functions
+ */
+
+#include <linux/module.h>
+#include <linux/time.h>
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/fcntl.h>
+#include <linux/stat.h>
+#include <linux/nfs_fs.h>
+#include <linux/nfs_mount.h>
+#include <linux/mm.h>
+#include <linux/pagemap.h>
+#include <linux/gfp.h>
+#include <linux/swap.h>
+
+#include <asm/uaccess.h>
+
+#include "delegation.h"
+#include "internal.h"
+#include "iostat.h"
+#include "fscache.h"
+#include "pnfs.h"
+
+#include "nfstrace.h"
+
+#define NFSDBG_FACILITY NFSDBG_FILE
+
+static const struct vm_operations_struct nfs_file_vm_ops;
+
+/* Hack for future NFS swap support */
+#ifndef IS_SWAPFILE
+# define IS_SWAPFILE(inode) (0)
+#endif
+
+int nfs_check_flags(int flags)
+{
+ if ((flags & (O_APPEND | O_DIRECT)) == (O_APPEND | O_DIRECT))
+ return -EINVAL;
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(nfs_check_flags);
+
+/*
+ * Open file
+ */
+static int
+nfs_file_open(struct inode *inode, struct file *filp)
+{
+ int res;
+
+ dprintk("NFS: open file(%pD2)\n", filp);
+
+ nfs_inc_stats(inode, NFSIOS_VFSOPEN);
+ res = nfs_check_flags(filp->f_flags);
+ if (res)
+ return res;
+
+ res = nfs_open(inode, filp);
+ return res;
+}
+
+int
+nfs_file_release(struct inode *inode, struct file *filp)
+{
+ dprintk("NFS: release(%pD2)\n", filp);
+
+ nfs_inc_stats(inode, NFSIOS_VFSRELEASE);
+ return nfs_release(inode, filp);
+}
+EXPORT_SYMBOL_GPL(nfs_file_release);
+
+/**
+ * nfs_revalidate_size - Revalidate the file size
+ * @inode - pointer to inode struct
+ * @file - pointer to struct file
+ *
+ * Revalidates the file length. This is basically a wrapper around
+ * nfs_revalidate_inode() that takes into account the fact that we may
+ * have cached writes (in which case we don't care about the server's
+ * idea of what the file length is), or O_DIRECT (in which case we
+ * shouldn't trust the cache).
+ */
+static int nfs_revalidate_file_size(struct inode *inode, struct file *filp)
+{
+ struct nfs_server *server = NFS_SERVER(inode);
+ struct nfs_inode *nfsi = NFS_I(inode);
+
+ if (nfs_have_delegated_attributes(inode))
+ goto out_noreval;
+
+ if (filp->f_flags & O_DIRECT)
+ goto force_reval;
+ if (nfsi->cache_validity & NFS_INO_REVAL_PAGECACHE)
+ goto force_reval;
+ if (nfs_attribute_timeout(inode))
+ goto force_reval;
+out_noreval:
+ return 0;
+force_reval:
+ return __nfs_revalidate_inode(server, inode);
+}
+
+loff_t nfs_file_llseek(struct file *filp, loff_t offset, int whence)
+{
+ dprintk("NFS: llseek file(%pD2, %lld, %d)\n",
+ filp, offset, whence);
+
+ /*
+ * whence == SEEK_END || SEEK_DATA || SEEK_HOLE => we must revalidate
+ * the cached file length
+ */
+ if (whence != SEEK_SET && whence != SEEK_CUR) {
+ struct inode *inode = filp->f_mapping->host;
+
+ int retval = nfs_revalidate_file_size(inode, filp);
+ if (retval < 0)
+ return (loff_t)retval;
+ }
+
+ return generic_file_llseek(filp, offset, whence);
+}
+EXPORT_SYMBOL_GPL(nfs_file_llseek);
+
+/*
+ * Flush all dirty pages, and check for write errors.
+ */
+int
+nfs_file_flush(struct file *file, fl_owner_t id)
+{
+ struct inode *inode = file_inode(file);
+
+ dprintk("NFS: flush(%pD2)\n", file);
+
+ nfs_inc_stats(inode, NFSIOS_VFSFLUSH);
+ if ((file->f_mode & FMODE_WRITE) == 0)
+ return 0;
+
+ /*
+ * If we're holding a write delegation, then just start the i/o
+ * but don't wait for completion (or send a commit).
+ */
+ if (NFS_PROTO(inode)->have_delegation(inode, FMODE_WRITE))
+ return filemap_fdatawrite(file->f_mapping);
+
+ /* Flush writes to the server and return any errors */
+ return vfs_fsync(file, 0);
+}
+EXPORT_SYMBOL_GPL(nfs_file_flush);
+
+ssize_t
+nfs_file_read(struct kiocb *iocb, struct iov_iter *to)
+{
+ struct inode *inode = file_inode(iocb->ki_filp);
+ ssize_t result;
+
+ if (iocb->ki_flags & IOCB_DIRECT)
+ return nfs_file_direct_read(iocb, to, iocb->ki_pos);
+
+ dprintk("NFS: read(%pD2, %zu@%lu)\n",
+ iocb->ki_filp,
+ iov_iter_count(to), (unsigned long) iocb->ki_pos);
+
+ result = nfs_revalidate_mapping_protected(inode, iocb->ki_filp->f_mapping);
+ if (!result) {
+ result = generic_file_read_iter(iocb, to);
+ if (result > 0)
+ nfs_add_stats(inode, NFSIOS_NORMALREADBYTES, result);
+ }
+ return result;
+}
+EXPORT_SYMBOL_GPL(nfs_file_read);
+
+ssize_t
+nfs_file_splice_read(struct file *filp, loff_t *ppos,
+ struct pipe_inode_info *pipe, size_t count,
+ unsigned int flags)
+{
+ struct inode *inode = file_inode(filp);
+ ssize_t res;
+
+ dprintk("NFS: splice_read(%pD2, %lu@%Lu)\n",
+ filp, (unsigned long) count, (unsigned long long) *ppos);
+
+ res = nfs_revalidate_mapping_protected(inode, filp->f_mapping);
+ if (!res) {
+ res = generic_file_splice_read(filp, ppos, pipe, count, flags);
+ if (res > 0)
+ nfs_add_stats(inode, NFSIOS_NORMALREADBYTES, res);
+ }
+ return res;
+}
+EXPORT_SYMBOL_GPL(nfs_file_splice_read);
+
+int
+nfs_file_mmap(struct file * file, struct vm_area_struct * vma)
+{
+ struct inode *inode = file_inode(file);
+ int status;
+
+ dprintk("NFS: mmap(%pD2)\n", file);
+
+ /* Note: generic_file_mmap() returns ENOSYS on nommu systems
+ * so we call that before revalidating the mapping
+ */
+ status = generic_file_mmap(file, vma);
+ if (!status) {
+ vma->vm_ops = &nfs_file_vm_ops;
+ status = nfs_revalidate_mapping(inode, file->f_mapping);
+ }
+ return status;
+}
+EXPORT_SYMBOL_GPL(nfs_file_mmap);
+
+/*
+ * Flush any dirty pages for this process, and check for write errors.
+ * The return status from this call provides a reliable indication of
+ * whether any write errors occurred for this process.
+ *
+ * Notice that it clears the NFS_CONTEXT_ERROR_WRITE before synching to
+ * disk, but it retrieves and clears ctx->error after synching, despite
+ * the two being set at the same time in nfs_context_set_write_error().
+ * This is because the former is used to notify the _next_ call to
+ * nfs_file_write() that a write error occurred, and hence cause it to
+ * fall back to doing a synchronous write.
+ */
+int
+nfs_file_fsync_commit(struct file *file, loff_t start, loff_t end, int datasync)
+{
+ struct nfs_open_context *ctx = nfs_file_open_context(file);
+ struct inode *inode = file_inode(file);
+ int have_error, do_resend, status;
+ int ret = 0;
+
+ dprintk("NFS: fsync file(%pD2) datasync %d\n", file, datasync);
+
+ nfs_inc_stats(inode, NFSIOS_VFSFSYNC);
+ do_resend = test_and_clear_bit(NFS_CONTEXT_RESEND_WRITES, &ctx->flags);
+ have_error = test_and_clear_bit(NFS_CONTEXT_ERROR_WRITE, &ctx->flags);
+ status = nfs_commit_inode(inode, FLUSH_SYNC);
+ have_error |= test_bit(NFS_CONTEXT_ERROR_WRITE, &ctx->flags);
+ if (have_error) {
+ ret = xchg(&ctx->error, 0);
+ if (ret)
+ goto out;
+ }
+ if (status < 0) {
+ ret = status;
+ goto out;
+ }
+ do_resend |= test_bit(NFS_CONTEXT_RESEND_WRITES, &ctx->flags);
+ if (do_resend)
+ ret = -EAGAIN;
+out:
+ return ret;
+}
+EXPORT_SYMBOL_GPL(nfs_file_fsync_commit);
+
+static int
+nfs_file_fsync(struct file *file, loff_t start, loff_t end, int datasync)
+{
+ int ret;
+ struct inode *inode = file_inode(file);
+
+ trace_nfs_fsync_enter(inode);
+
+ nfs_inode_dio_wait(inode);
+ do {
+ ret = filemap_write_and_wait_range(inode->i_mapping, start, end);
+ if (ret != 0)
+ break;
+ mutex_lock(&inode->i_mutex);
+ ret = nfs_file_fsync_commit(file, start, end, datasync);
+ mutex_unlock(&inode->i_mutex);
+ /*
+ * If nfs_file_fsync_commit detected a server reboot, then
+ * resend all dirty pages that might have been covered by
+ * the NFS_CONTEXT_RESEND_WRITES flag
+ */
+ start = 0;
+ end = LLONG_MAX;
+ } while (ret == -EAGAIN);
+
+ trace_nfs_fsync_exit(inode, ret);
+ return ret;
+}
+
+/*
+ * Decide whether a read/modify/write cycle may be more efficient
+ * then a modify/write/read cycle when writing to a page in the
+ * page cache.
+ *
+ * The modify/write/read cycle may occur if a page is read before
+ * being completely filled by the writer. In this situation, the
+ * page must be completely written to stable storage on the server
+ * before it can be refilled by reading in the page from the server.
+ * This can lead to expensive, small, FILE_SYNC mode writes being
+ * done.
+ *
+ * It may be more efficient to read the page first if the file is
+ * open for reading in addition to writing, the page is not marked
+ * as Uptodate, it is not dirty or waiting to be committed,
+ * indicating that it was previously allocated and then modified,
+ * that there were valid bytes of data in that range of the file,
+ * and that the new data won't completely replace the old data in
+ * that range of the file.
+ */
+static int nfs_want_read_modify_write(struct file *file, struct page *page,
+ loff_t pos, unsigned len)
+{
+ unsigned int pglen = nfs_page_length(page);
+ unsigned int offset = pos & (PAGE_CACHE_SIZE - 1);
+ unsigned int end = offset + len;
+
+ if (pnfs_ld_read_whole_page(file->f_mapping->host)) {
+ if (!PageUptodate(page))
+ return 1;
+ return 0;
+ }
+
+ if ((file->f_mode & FMODE_READ) && /* open for read? */
+ !PageUptodate(page) && /* Uptodate? */
+ !PagePrivate(page) && /* i/o request already? */
+ pglen && /* valid bytes of file? */
+ (end < pglen || offset)) /* replace all valid bytes? */
+ return 1;
+ return 0;
+}
+
+/*
+ * This does the "real" work of the write. We must allocate and lock the
+ * page to be sent back to the generic routine, which then copies the
+ * data from user space.
+ *
+ * If the writer ends up delaying the write, the writer needs to
+ * increment the page use counts until he is done with the page.
+ */
+static int nfs_write_begin(struct file *file, struct address_space *mapping,
+ loff_t pos, unsigned len, unsigned flags,
+ struct page **pagep, void **fsdata)
+{
+ int ret;
+ pgoff_t index = pos >> PAGE_CACHE_SHIFT;
+ struct page *page;
+ int once_thru = 0;
+
+ dfprintk(PAGECACHE, "NFS: write_begin(%pD2(%lu), %u@%lld)\n",
+ file, mapping->host->i_ino, len, (long long) pos);
+
+start:
+ /*
+ * Prevent starvation issues if someone is doing a consistency
+ * sync-to-disk
+ */
+ ret = wait_on_bit_action(&NFS_I(mapping->host)->flags, NFS_INO_FLUSHING,
+ nfs_wait_bit_killable, TASK_KILLABLE);
+ if (ret)
+ return ret;
+ /*
+ * Wait for O_DIRECT to complete
+ */
+ nfs_inode_dio_wait(mapping->host);
+
+ page = grab_cache_page_write_begin(mapping, index, flags);
+ if (!page)
+ return -ENOMEM;
+ *pagep = page;
+
+ ret = nfs_flush_incompatible(file, page);
+ if (ret) {
+ unlock_page(page);
+ page_cache_release(page);
+ } else if (!once_thru &&
+ nfs_want_read_modify_write(file, page, pos, len)) {
+ once_thru = 1;
+ ret = nfs_readpage(file, page);
+ page_cache_release(page);
+ if (!ret)
+ goto start;
+ }
+ return ret;
+}
+
+static int nfs_write_end(struct file *file, struct address_space *mapping,
+ loff_t pos, unsigned len, unsigned copied,
+ struct page *page, void *fsdata)
+{
+ unsigned offset = pos & (PAGE_CACHE_SIZE - 1);
+ struct nfs_open_context *ctx = nfs_file_open_context(file);
+ int status;
+
+ dfprintk(PAGECACHE, "NFS: write_end(%pD2(%lu), %u@%lld)\n",
+ file, mapping->host->i_ino, len, (long long) pos);
+
+ /*
+ * Zero any uninitialised parts of the page, and then mark the page
+ * as up to date if it turns out that we're extending the file.
+ */
+ if (!PageUptodate(page)) {
+ unsigned pglen = nfs_page_length(page);
+ unsigned end = offset + len;
+
+ if (pglen == 0) {
+ zero_user_segments(page, 0, offset,
+ end, PAGE_CACHE_SIZE);
+ SetPageUptodate(page);
+ } else if (end >= pglen) {
+ zero_user_segment(page, end, PAGE_CACHE_SIZE);
+ if (offset == 0)
+ SetPageUptodate(page);
+ } else
+ zero_user_segment(page, pglen, PAGE_CACHE_SIZE);
+ }
+
+ status = nfs_updatepage(file, page, offset, copied);
+
+ unlock_page(page);
+ page_cache_release(page);
+
+ if (status < 0)
+ return status;
+ NFS_I(mapping->host)->write_io += copied;
+
+ if (nfs_ctx_key_to_expire(ctx)) {
+ status = nfs_wb_all(mapping->host);
+ if (status < 0)
+ return status;
+ }
+
+ return copied;
+}
+
+/*
+ * Partially or wholly invalidate a page
+ * - Release the private state associated with a page if undergoing complete
+ * page invalidation
+ * - Called if either PG_private or PG_fscache is set on the page
+ * - Caller holds page lock
+ */
+static void nfs_invalidate_page(struct page *page, unsigned int offset,
+ unsigned int length)
+{
+ dfprintk(PAGECACHE, "NFS: invalidate_page(%p, %u, %u)\n",
+ page, offset, length);
+
+ if (offset != 0 || length < PAGE_CACHE_SIZE)
+ return;
+ /* Cancel any unstarted writes on this page */
+ nfs_wb_page_cancel(page_file_mapping(page)->host, page);
+
+ nfs_fscache_invalidate_page(page, page->mapping->host);
+}
+
+/*
+ * Attempt to release the private state associated with a page
+ * - Called if either PG_private or PG_fscache is set on the page
+ * - Caller holds page lock
+ * - Return true (may release page) or false (may not)
+ */
+static int nfs_release_page(struct page *page, gfp_t gfp)
+{
+ struct address_space *mapping = page->mapping;
+
+ dfprintk(PAGECACHE, "NFS: release_page(%p)\n", page);
+
+ /* Always try to initiate a 'commit' if relevant, but only
+ * wait for it if __GFP_WAIT is set. Even then, only wait 1
+ * second and only if the 'bdi' is not congested.
+ * Waiting indefinitely can cause deadlocks when the NFS
+ * server is on this machine, when a new TCP connection is
+ * needed and in other rare cases. There is no particular
+ * need to wait extensively here. A short wait has the
+ * benefit that someone else can worry about the freezer.
+ */
+ if (mapping) {
+ struct nfs_server *nfss = NFS_SERVER(mapping->host);
+ nfs_commit_inode(mapping->host, 0);
+ if ((gfp & __GFP_WAIT) &&
+ !bdi_write_congested(&nfss->backing_dev_info)) {
+ wait_on_page_bit_killable_timeout(page, PG_private,
+ HZ);
+ if (PagePrivate(page))
+ set_bdi_congested(&nfss->backing_dev_info,
+ BLK_RW_ASYNC);
+ }
+ }
+ /* If PagePrivate() is set, then the page is not freeable */
+ if (PagePrivate(page))
+ return 0;
+ return nfs_fscache_release_page(page, gfp);
+}
+
+static void nfs_check_dirty_writeback(struct page *page,
+ bool *dirty, bool *writeback)
+{
+ struct nfs_inode *nfsi;
+ struct address_space *mapping = page_file_mapping(page);
+
+ if (!mapping || PageSwapCache(page))
+ return;
+
+ /*
+ * Check if an unstable page is currently being committed and
+ * if so, have the VM treat it as if the page is under writeback
+ * so it will not block due to pages that will shortly be freeable.
+ */
+ nfsi = NFS_I(mapping->host);
+ if (test_bit(NFS_INO_COMMIT, &nfsi->flags)) {
+ *writeback = true;
+ return;
+ }
+
+ /*
+ * If PagePrivate() is set, then the page is not freeable and as the
+ * inode is not being committed, it's not going to be cleaned in the
+ * near future so treat it as dirty
+ */
+ if (PagePrivate(page))
+ *dirty = true;
+}
+
+/*
+ * Attempt to clear the private state associated with a page when an error
+ * occurs that requires the cached contents of an inode to be written back or
+ * destroyed
+ * - Called if either PG_private or fscache is set on the page
+ * - Caller holds page lock
+ * - Return 0 if successful, -error otherwise
+ */
+static int nfs_launder_page(struct page *page)
+{
+ struct inode *inode = page_file_mapping(page)->host;
+ struct nfs_inode *nfsi = NFS_I(inode);
+
+ dfprintk(PAGECACHE, "NFS: launder_page(%ld, %llu)\n",
+ inode->i_ino, (long long)page_offset(page));
+
+ nfs_fscache_wait_on_page_write(nfsi, page);
+ return nfs_wb_page(inode, page);
+}
+
+#ifdef CONFIG_NFS_SWAP
+static int nfs_swap_activate(struct swap_info_struct *sis, struct file *file,
+ sector_t *span)
+{
+ int ret;
+ struct rpc_clnt *clnt = NFS_CLIENT(file->f_mapping->host);
+
+ *span = sis->pages;
+
+ rcu_read_lock();
+ ret = xs_swapper(rcu_dereference(clnt->cl_xprt), 1);
+ rcu_read_unlock();
+
+ return ret;
+}
+
+static void nfs_swap_deactivate(struct file *file)
+{
+ struct rpc_clnt *clnt = NFS_CLIENT(file->f_mapping->host);
+
+ rcu_read_lock();
+ xs_swapper(rcu_dereference(clnt->cl_xprt), 0);
+ rcu_read_unlock();
+}
+#endif
+
+const struct address_space_operations nfs_file_aops = {
+ .readpage = nfs_readpage,
+ .readpages = nfs_readpages,
+ .set_page_dirty = __set_page_dirty_nobuffers,
+ .writepage = nfs_writepage,
+ .writepages = nfs_writepages,
+ .write_begin = nfs_write_begin,
+ .write_end = nfs_write_end,
+ .invalidatepage = nfs_invalidate_page,
+ .releasepage = nfs_release_page,
+ .direct_IO = nfs_direct_IO,
+ .migratepage = nfs_migrate_page,
+ .launder_page = nfs_launder_page,
+ .is_dirty_writeback = nfs_check_dirty_writeback,
+ .error_remove_page = generic_error_remove_page,
+#ifdef CONFIG_NFS_SWAP
+ .swap_activate = nfs_swap_activate,
+ .swap_deactivate = nfs_swap_deactivate,
+#endif
+};
+
+/*
+ * Notification that a PTE pointing to an NFS page is about to be made
+ * writable, implying that someone is about to modify the page through a
+ * shared-writable mapping
+ */
+static int nfs_vm_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
+{
+ struct page *page = vmf->page;
+ struct file *filp = vma->vm_file;
+ struct inode *inode = file_inode(filp);
+ unsigned pagelen;
+ int ret = VM_FAULT_NOPAGE;
+ struct address_space *mapping;
+
+ dfprintk(PAGECACHE, "NFS: vm_page_mkwrite(%pD2(%lu), offset %lld)\n",
+ filp, filp->f_mapping->host->i_ino,
+ (long long)page_offset(page));
+
+ /* make sure the cache has finished storing the page */
+ nfs_fscache_wait_on_page_write(NFS_I(inode), page);
+
+ wait_on_bit_action(&NFS_I(inode)->flags, NFS_INO_INVALIDATING,
+ nfs_wait_bit_killable, TASK_KILLABLE);
+
+ lock_page(page);
+ mapping = page_file_mapping(page);
+ if (mapping != inode->i_mapping)
+ goto out_unlock;
+
+ wait_on_page_writeback(page);
+
+ pagelen = nfs_page_length(page);
+ if (pagelen == 0)
+ goto out_unlock;
+
+ ret = VM_FAULT_LOCKED;
+ if (nfs_flush_incompatible(filp, page) == 0 &&
+ nfs_updatepage(filp, page, 0, pagelen) == 0)
+ goto out;
+
+ ret = VM_FAULT_SIGBUS;
+out_unlock:
+ unlock_page(page);
+out:
+ return ret;
+}
+
+static const struct vm_operations_struct nfs_file_vm_ops = {
+ .fault = filemap_fault,
+ .map_pages = filemap_map_pages,
+ .page_mkwrite = nfs_vm_page_mkwrite,
+};
+
+static int nfs_need_sync_write(struct file *filp, struct inode *inode)
+{
+ struct nfs_open_context *ctx;
+
+ if (IS_SYNC(inode) || (filp->f_flags & O_DSYNC))
+ return 1;
+ ctx = nfs_file_open_context(filp);
+ if (test_bit(NFS_CONTEXT_ERROR_WRITE, &ctx->flags) ||
+ nfs_ctx_key_to_expire(ctx))
+ return 1;
+ return 0;
+}
+
+ssize_t nfs_file_write(struct kiocb *iocb, struct iov_iter *from)
+{
+ struct file *file = iocb->ki_filp;
+ struct inode *inode = file_inode(file);
+ unsigned long written = 0;
+ ssize_t result;
+ size_t count = iov_iter_count(from);
+
+ result = nfs_key_timeout_notify(file, inode);
+ if (result)
+ return result;
+
+ if (iocb->ki_flags & IOCB_DIRECT) {
+ result = generic_write_checks(iocb, from);
+ if (result <= 0)
+ return result;
+ return nfs_file_direct_write(iocb, from);
+ }
+
+ dprintk("NFS: write(%pD2, %zu@%Ld)\n",
+ file, count, (long long) iocb->ki_pos);
+
+ result = -EBUSY;
+ if (IS_SWAPFILE(inode))
+ goto out_swapfile;
+ /*
+ * O_APPEND implies that we must revalidate the file length.
+ */
+ if (iocb->ki_flags & IOCB_APPEND) {
+ result = nfs_revalidate_file_size(inode, file);
+ if (result)
+ goto out;
+ }
+
+ result = count;
+ if (!count)
+ goto out;
+
+ result = generic_file_write_iter(iocb, from);
+ if (result > 0)
+ written = result;
+
+ /* Return error values for O_DSYNC and IS_SYNC() */
+ if (result >= 0 && nfs_need_sync_write(file, inode)) {
+ int err = vfs_fsync(file, 0);
+ if (err < 0)
+ result = err;
+ }
+ if (result > 0)
+ nfs_add_stats(inode, NFSIOS_NORMALWRITTENBYTES, written);
+out:
+ return result;
+
+out_swapfile:
+ printk(KERN_INFO "NFS: attempt to write to active swap file!\n");
+ goto out;
+}
+EXPORT_SYMBOL_GPL(nfs_file_write);
+
+static int
+do_getlk(struct file *filp, int cmd, struct file_lock *fl, int is_local)
+{
+ struct inode *inode = filp->f_mapping->host;
+ int status = 0;
+ unsigned int saved_type = fl->fl_type;
+
+ /* Try local locking first */
+ posix_test_lock(filp, fl);
+ if (fl->fl_type != F_UNLCK) {
+ /* found a conflict */
+ goto out;
+ }
+ fl->fl_type = saved_type;
+
+ if (NFS_PROTO(inode)->have_delegation(inode, FMODE_READ))
+ goto out_noconflict;
+
+ if (is_local)
+ goto out_noconflict;
+
+ status = NFS_PROTO(inode)->lock(filp, cmd, fl);
+out:
+ return status;
+out_noconflict:
+ fl->fl_type = F_UNLCK;
+ goto out;
+}
+
+static int do_vfs_lock(struct file *file, struct file_lock *fl)
+{
+ int res = 0;
+ switch (fl->fl_flags & (FL_POSIX|FL_FLOCK)) {
+ case FL_POSIX:
+ res = posix_lock_file_wait(file, fl);
+ break;
+ case FL_FLOCK:
+ res = flock_lock_file_wait(file, fl);
+ break;
+ default:
+ BUG();
+ }
+ return res;
+}
+
+static int
+do_unlk(struct file *filp, int cmd, struct file_lock *fl, int is_local)
+{
+ struct inode *inode = filp->f_mapping->host;
+ struct nfs_lock_context *l_ctx;
+ int status;
+
+ /*
+ * Flush all pending writes before doing anything
+ * with locks..
+ */
+ vfs_fsync(filp, 0);
+
+ l_ctx = nfs_get_lock_context(nfs_file_open_context(filp));
+ if (!IS_ERR(l_ctx)) {
+ status = nfs_iocounter_wait(&l_ctx->io_count);
+ nfs_put_lock_context(l_ctx);
+ if (status < 0)
+ return status;
+ }
+
+ /* NOTE: special case
+ * If we're signalled while cleaning up locks on process exit, we
+ * still need to complete the unlock.
+ */
+ /*
+ * Use local locking if mounted with "-onolock" or with appropriate
+ * "-olocal_lock="
+ */
+ if (!is_local)
+ status = NFS_PROTO(inode)->lock(filp, cmd, fl);
+ else
+ status = do_vfs_lock(filp, fl);
+ return status;
+}
+
+static int
+is_time_granular(struct timespec *ts) {
+ return ((ts->tv_sec == 0) && (ts->tv_nsec <= 1000));
+}
+
+static int
+do_setlk(struct file *filp, int cmd, struct file_lock *fl, int is_local)
+{
+ struct inode *inode = filp->f_mapping->host;
+ int status;
+
+ /*
+ * Flush all pending writes before doing anything
+ * with locks..
+ */
+ status = nfs_sync_mapping(filp->f_mapping);
+ if (status != 0)
+ goto out;
+
+ /*
+ * Use local locking if mounted with "-onolock" or with appropriate
+ * "-olocal_lock="
+ */
+ if (!is_local)
+ status = NFS_PROTO(inode)->lock(filp, cmd, fl);
+ else
+ status = do_vfs_lock(filp, fl);
+ if (status < 0)
+ goto out;
+
+ /*
+ * Revalidate the cache if the server has time stamps granular
+ * enough to detect subsecond changes. Otherwise, clear the
+ * cache to prevent missing any changes.
+ *
+ * This makes locking act as a cache coherency point.
+ */
+ nfs_sync_mapping(filp->f_mapping);
+ if (!NFS_PROTO(inode)->have_delegation(inode, FMODE_READ)) {
+ if (is_time_granular(&NFS_SERVER(inode)->time_delta))
+ __nfs_revalidate_inode(NFS_SERVER(inode), inode);
+ else
+ nfs_zap_caches(inode);
+ }
+out:
+ return status;
+}
+
+/*
+ * Lock a (portion of) a file
+ */
+int nfs_lock(struct file *filp, int cmd, struct file_lock *fl)
+{
+ struct inode *inode = filp->f_mapping->host;
+ int ret = -ENOLCK;
+ int is_local = 0;
+
+ dprintk("NFS: lock(%pD2, t=%x, fl=%x, r=%lld:%lld)\n",
+ filp, fl->fl_type, fl->fl_flags,
+ (long long)fl->fl_start, (long long)fl->fl_end);
+
+ nfs_inc_stats(inode, NFSIOS_VFSLOCK);
+
+ /* No mandatory locks over NFS */
+ if (__mandatory_lock(inode) && fl->fl_type != F_UNLCK)
+ goto out_err;
+
+ if (NFS_SERVER(inode)->flags & NFS_MOUNT_LOCAL_FCNTL)
+ is_local = 1;
+
+ if (NFS_PROTO(inode)->lock_check_bounds != NULL) {
+ ret = NFS_PROTO(inode)->lock_check_bounds(fl);
+ if (ret < 0)
+ goto out_err;
+ }
+
+ if (IS_GETLK(cmd))
+ ret = do_getlk(filp, cmd, fl, is_local);
+ else if (fl->fl_type == F_UNLCK)
+ ret = do_unlk(filp, cmd, fl, is_local);
+ else
+ ret = do_setlk(filp, cmd, fl, is_local);
+out_err:
+ return ret;
+}
+EXPORT_SYMBOL_GPL(nfs_lock);
+
+/*
+ * Lock a (portion of) a file
+ */
+int nfs_flock(struct file *filp, int cmd, struct file_lock *fl)
+{
+ struct inode *inode = filp->f_mapping->host;
+ int is_local = 0;
+
+ dprintk("NFS: flock(%pD2, t=%x, fl=%x)\n",
+ filp, fl->fl_type, fl->fl_flags);
+
+ if (!(fl->fl_flags & FL_FLOCK))
+ return -ENOLCK;
+
+ /*
+ * The NFSv4 protocol doesn't support LOCK_MAND, which is not part of
+ * any standard. In principle we might be able to support LOCK_MAND
+ * on NFSv2/3 since NLMv3/4 support DOS share modes, but for now the
+ * NFS code is not set up for it.
+ */
+ if (fl->fl_type & LOCK_MAND)
+ return -EINVAL;
+
+ if (NFS_SERVER(inode)->flags & NFS_MOUNT_LOCAL_FLOCK)
+ is_local = 1;
+
+ /* We're simulating flock() locks using posix locks on the server */
+ if (fl->fl_type == F_UNLCK)
+ return do_unlk(filp, cmd, fl, is_local);
+ return do_setlk(filp, cmd, fl, is_local);
+}
+EXPORT_SYMBOL_GPL(nfs_flock);
+
+const struct file_operations nfs_file_operations = {
+ .llseek = nfs_file_llseek,
+ .read_iter = nfs_file_read,
+ .write_iter = nfs_file_write,
+ .mmap = nfs_file_mmap,
+ .open = nfs_file_open,
+ .flush = nfs_file_flush,
+ .release = nfs_file_release,
+ .fsync = nfs_file_fsync,
+ .lock = nfs_lock,
+ .flock = nfs_flock,
+ .splice_read = nfs_file_splice_read,
+ .splice_write = iter_file_splice_write,
+ .check_flags = nfs_check_flags,
+ .setlease = simple_nosetlease,
+};
+EXPORT_SYMBOL_GPL(nfs_file_operations);
Code Review / kvmfornfv.git / blobdiff