/* * 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/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/slab.h> #include <linux/pagemap.h> #include <linux/smp_lock.h> #include <linux/aio.h> #include <asm/uaccess.h> #include <asm/system.h> #include "delegation.h" #include "internal.h" #include "iostat.h" #define NFSDBG_FACILITY NFSDBG_FILE static int nfs_file_open(struct inode *, struct file *); static int nfs_file_release(struct inode *, struct file *); static loff_t nfs_file_llseek(struct file *file, loff_t offset, int origin); static int nfs_file_mmap(struct file *, struct vm_area_struct *); static ssize_t nfs_file_splice_read(struct file *filp, loff_t *ppos, struct pipe_inode_info *pipe, size_t count, unsigned int flags); static ssize_t nfs_file_read(struct kiocb *, const struct iovec *iov, unsigned long nr_segs, loff_t pos); static ssize_t nfs_file_write(struct kiocb *, const struct iovec *iov, unsigned long nr_segs, loff_t pos); static int nfs_file_flush(struct file *, fl_owner_t id); static int nfs_file_fsync(struct file *, struct dentry *dentry, int datasync); static int nfs_check_flags(int flags); static int nfs_lock(struct file *filp, int cmd, struct file_lock *fl); static int nfs_flock(struct file *filp, int cmd, struct file_lock *fl); static int nfs_setlease(struct file *file, long arg, struct file_lock **fl); static struct vm_operations_struct nfs_file_vm_ops; const struct file_operations nfs_file_operations = { .llseek = nfs_file_llseek, .read = do_sync_read, .write = do_sync_write, .aio_read = nfs_file_read, .aio_write = nfs_file_write, #ifdef CONFIG_MMU .mmap = nfs_file_mmap, #else .mmap = generic_file_mmap, #endif .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, .check_flags = nfs_check_flags, .setlease = nfs_setlease, }; const struct inode_operations nfs_file_inode_operations = { .permission = nfs_permission, .getattr = nfs_getattr, .setattr = nfs_setattr, }; #ifdef CONFIG_NFS_V3 const struct inode_operations nfs3_file_inode_operations = { .permission = nfs_permission, .getattr = nfs_getattr, .setattr = nfs_setattr, .listxattr = nfs3_listxattr, .getxattr = nfs3_getxattr, .setxattr = nfs3_setxattr, .removexattr = nfs3_removexattr, }; #endif /* CONFIG_NFS_v3 */ /* Hack for future NFS swap support */ #ifndef IS_SWAPFILE # define IS_SWAPFILE(inode) (0) #endif static int nfs_check_flags(int flags) { if ((flags & (O_APPEND | O_DIRECT)) == (O_APPEND | O_DIRECT)) return -EINVAL; return 0; } /* * Open file */ static int nfs_file_open(struct inode *inode, struct file *filp) { int res; dprintk("NFS: open file(%s/%s)\n", filp->f_path.dentry->d_parent->d_name.name, filp->f_path.dentry->d_name.name); res = nfs_check_flags(filp->f_flags); if (res) return res; nfs_inc_stats(inode, NFSIOS_VFSOPEN); res = nfs_open(inode, filp); return res; } static int nfs_file_release(struct inode *inode, struct file *filp) { struct dentry *dentry = filp->f_path.dentry; dprintk("NFS: release(%s/%s)\n", dentry->d_parent->d_name.name, dentry->d_name.name); /* Ensure that dirty pages are flushed out with the right creds */ if (filp->f_mode & FMODE_WRITE) nfs_wb_all(dentry->d_inode); nfs_inc_stats(inode, NFSIOS_VFSRELEASE); return nfs_release(inode, filp); } /** * 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 (server->flags & NFS_MOUNT_NOAC) goto force_reval; if (filp->f_flags & O_DIRECT) goto force_reval; if (nfsi->npages != 0) return 0; if (!(nfsi->cache_validity & NFS_INO_REVAL_PAGECACHE) && !nfs_attribute_timeout(inode)) return 0; force_reval: return __nfs_revalidate_inode(server, inode); } static loff_t nfs_file_llseek(struct file *filp, loff_t offset, int origin) { loff_t loff; dprintk("NFS: llseek file(%s/%s, %lld, %d)\n", filp->f_path.dentry->d_parent->d_name.name, filp->f_path.dentry->d_name.name, offset, origin); /* origin == SEEK_END => we must revalidate the cached file length */ if (origin == SEEK_END) { struct inode *inode = filp->f_mapping->host; int retval = nfs_revalidate_file_size(inode, filp); if (retval < 0) return (loff_t)retval; spin_lock(&inode->i_lock); loff = generic_file_llseek_unlocked(filp, offset, origin); spin_unlock(&inode->i_lock); } else loff = generic_file_llseek_unlocked(filp, offset, origin); return loff; } /* * Helper for nfs_file_flush() and nfs_file_fsync() * * 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 occured, and hence cause it to * fall back to doing a synchronous write. */ static int nfs_do_fsync(struct nfs_open_context *ctx, struct inode *inode) { int have_error, status; int ret = 0; have_error = test_and_clear_bit(NFS_CONTEXT_ERROR_WRITE, &ctx->flags); status = nfs_wb_all(inode); have_error |= test_bit(NFS_CONTEXT_ERROR_WRITE, &ctx->flags); if (have_error) ret = xchg(&ctx->error, 0); if (!ret) ret = status; return ret; } /* * Flush all dirty pages, and check for write errors. */ static int nfs_file_flush(struct file *file, fl_owner_t id) { struct nfs_open_context *ctx = nfs_file_open_context(file); struct dentry *dentry = file->f_path.dentry; struct inode *inode = dentry->d_inode; int status; dprintk("NFS: flush(%s/%s)\n", dentry->d_parent->d_name.name, dentry->d_name.name); if ((file->f_mode & FMODE_WRITE) == 0) return 0; nfs_inc_stats(inode, NFSIOS_VFSFLUSH); /* Ensure that data+attribute caches are up to date after close() */ status = nfs_do_fsync(ctx, inode); if (!status) nfs_revalidate_inode(NFS_SERVER(inode), inode); return status; } static ssize_t nfs_file_read(struct kiocb *iocb, const struct iovec *iov, unsigned long nr_segs, loff_t pos) { struct dentry * dentry = iocb->ki_filp->f_path.dentry; struct inode * inode = dentry->d_inode; ssize_t result; size_t count = iov_length(iov, nr_segs); if (iocb->ki_filp->f_flags & O_DIRECT) return nfs_file_direct_read(iocb, iov, nr_segs, pos); dprintk("NFS: read(%s/%s, %lu@%lu)\n", dentry->d_parent->d_name.name, dentry->d_name.name, (unsigned long) count, (unsigned long) pos); result = nfs_revalidate_mapping(inode, iocb->ki_filp->f_mapping); nfs_add_stats(inode, NFSIOS_NORMALREADBYTES, count); if (!result) result = generic_file_aio_read(iocb, iov, nr_segs, pos); return result; } static ssize_t nfs_file_splice_read(struct file *filp, loff_t *ppos, struct pipe_inode_info *pipe, size_t count, unsigned int flags) { struct dentry *dentry = filp->f_path.dentry; struct inode *inode = dentry->d_inode; ssize_t res; dprintk("NFS: splice_read(%s/%s, %lu@%Lu)\n", dentry->d_parent->d_name.name, dentry->d_name.name, (unsigned long) count, (unsigned long long) *ppos); res = nfs_revalidate_mapping(inode, filp->f_mapping); if (!res) res = generic_file_splice_read(filp, ppos, pipe, count, flags); return res; } static int nfs_file_mmap(struct file * file, struct vm_area_struct * vma) { struct dentry *dentry = file->f_path.dentry; struct inode *inode = dentry->d_inode; int status; dprintk("NFS: mmap(%s/%s)\n", dentry->d_parent->d_name.name, dentry->d_name.name); status = nfs_revalidate_mapping(inode, file->f_mapping); if (!status) { vma->vm_ops = &nfs_file_vm_ops; vma->vm_flags |= VM_CAN_NONLINEAR; file_accessed(file); } return status; } /* * 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. */ static int nfs_file_fsync(struct file *file, struct dentry *dentry, int datasync) { struct nfs_open_context *ctx = nfs_file_open_context(file); struct inode *inode = dentry->d_inode; dprintk("NFS: fsync file(%s/%s) datasync %d\n", dentry->d_parent->d_name.name, dentry->d_name.name, datasync); nfs_inc_stats(inode, NFSIOS_VFSFSYNC); return nfs_do_fsync(ctx, inode); } /* * 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; struct page *page; index = pos >> PAGE_CACHE_SHIFT; dfprintk(PAGECACHE, "NFS: write_begin(%s/%s(%ld), %u@%lld)\n", file->f_path.dentry->d_parent->d_name.name, file->f_path.dentry->d_name.name, mapping->host->i_ino, len, (long long) pos); page = __grab_cache_page(mapping, index); if (!page) return -ENOMEM; *pagep = page; ret = nfs_flush_incompatible(file, page); if (ret) { unlock_page(page); page_cache_release(page); } 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); int status; dfprintk(PAGECACHE, "NFS: write_end(%s/%s(%ld), %u@%lld)\n", file->f_path.dentry->d_parent->d_name.name, file->f_path.dentry->d_name.name, 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; return copied; } static void nfs_invalidate_page(struct page *page, unsigned long offset) { dfprintk(PAGECACHE, "NFS: invalidate_page(%p, %lu)\n", page, offset); if (offset != 0) return; /* Cancel any unstarted writes on this page */ nfs_wb_page_cancel(page->mapping->host, page); } static int nfs_release_page(struct page *page, gfp_t gfp) { dfprintk(PAGECACHE, "NFS: release_page(%p)\n", page); /* If PagePrivate() is set, then the page is not freeable */ return 0; } static int nfs_launder_page(struct page *page) { struct inode *inode = page->mapping->host; dfprintk(PAGECACHE, "NFS: launder_page(%ld, %llu)\n", inode->i_ino, (long long)page_offset(page)); return nfs_wb_page(inode, page); } 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, .launder_page = nfs_launder_page, }; static int nfs_vm_page_mkwrite(struct vm_area_struct *vma, struct page *page) { struct file *filp = vma->vm_file; struct dentry *dentry = filp->f_path.dentry; unsigned pagelen; int ret = -EINVAL; struct address_space *mapping; dfprintk(PAGECACHE, "NFS: vm_page_mkwrite(%s/%s(%ld), offset %lld)\n", dentry->d_parent->d_name.name, dentry->d_name.name, filp->f_mapping->host->i_ino, (long long)page_offset(page)); lock_page(page); mapping = page->mapping; if (mapping != dentry->d_inode->i_mapping) goto out_unlock; ret = 0; pagelen = nfs_page_length(page); if (pagelen == 0) goto out_unlock; ret = nfs_flush_incompatible(filp, page); if (ret != 0) goto out_unlock; ret = nfs_updatepage(filp, page, 0, pagelen); if (ret == 0) ret = pagelen; out_unlock: unlock_page(page); return ret; } static struct vm_operations_struct nfs_file_vm_ops = { .fault = filemap_fault, .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_SYNC)) return 1; ctx = nfs_file_open_context(filp); if (test_bit(NFS_CONTEXT_ERROR_WRITE, &ctx->flags)) return 1; return 0; } static ssize_t nfs_file_write(struct kiocb *iocb, const struct iovec *iov, unsigned long nr_segs, loff_t pos) { struct dentry * dentry = iocb->ki_filp->f_path.dentry; struct inode * inode = dentry->d_inode; ssize_t result; size_t count = iov_length(iov, nr_segs); if (iocb->ki_filp->f_flags & O_DIRECT) return nfs_file_direct_write(iocb, iov, nr_segs, pos); dprintk("NFS: write(%s/%s, %lu@%Ld)\n", dentry->d_parent->d_name.name, dentry->d_name.name, (unsigned long) count, (long long) pos); result = -EBUSY; if (IS_SWAPFILE(inode)) goto out_swapfile; /* * O_APPEND implies that we must revalidate the file length. */ if (iocb->ki_filp->f_flags & O_APPEND) { result = nfs_revalidate_file_size(inode, iocb->ki_filp); if (result) goto out; } result = count; if (!count) goto out; nfs_add_stats(inode, NFSIOS_NORMALWRITTENBYTES, count); result = generic_file_aio_write(iocb, iov, nr_segs, pos); /* Return error values for O_SYNC and IS_SYNC() */ if (result >= 0 && nfs_need_sync_write(iocb->ki_filp, inode)) { int err = nfs_do_fsync(nfs_file_open_context(iocb->ki_filp), inode); if (err < 0) result = err; } out: return result; out_swapfile: printk(KERN_INFO "NFS: attempt to write to active swap file!\n"); goto out; } static int do_getlk(struct file *filp, int cmd, struct file_lock *fl) { struct inode *inode = filp->f_mapping->host; int status = 0; lock_kernel(); /* Try local locking first */ posix_test_lock(filp, fl); if (fl->fl_type != F_UNLCK) { /* found a conflict */ goto out; } if (nfs_have_delegation(inode, FMODE_READ)) goto out_noconflict; if (NFS_SERVER(inode)->flags & NFS_MOUNT_NONLM) goto out_noconflict; status = NFS_PROTO(inode)->lock(filp, cmd, fl); out: unlock_kernel(); 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(); } if (res < 0) dprintk(KERN_WARNING "%s: VFS is out of sync with lock manager" " - error %d!\n", __func__, res); return res; } static int do_unlk(struct file *filp, int cmd, struct file_lock *fl) { struct inode *inode = filp->f_mapping->host; int status; /* * Flush all pending writes before doing anything * with locks.. */ nfs_sync_mapping(filp->f_mapping); /* NOTE: special case * If we're signalled while cleaning up locks on process exit, we * still need to complete the unlock. */ lock_kernel(); /* Use local locking if mounted with "-onolock" */ if (!(NFS_SERVER(inode)->flags & NFS_MOUNT_NONLM)) status = NFS_PROTO(inode)->lock(filp, cmd, fl); else status = do_vfs_lock(filp, fl); unlock_kernel(); return status; } static int do_setlk(struct file *filp, int cmd, struct file_lock *fl) { 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; lock_kernel(); /* Use local locking if mounted with "-onolock" */ if (!(NFS_SERVER(inode)->flags & NFS_MOUNT_NONLM)) status = NFS_PROTO(inode)->lock(filp, cmd, fl); else status = do_vfs_lock(filp, fl); unlock_kernel(); if (status < 0) goto out; /* * Make sure we clear the cache whenever we try to get the lock. * This makes locking act as a cache coherency point. */ nfs_sync_mapping(filp->f_mapping); if (!nfs_have_delegation(inode, FMODE_READ)) nfs_zap_caches(inode); out: return status; } /* * Lock a (portion of) a file */ static int nfs_lock(struct file *filp, int cmd, struct file_lock *fl) { struct inode *inode = filp->f_mapping->host; int ret = -ENOLCK; dprintk("NFS: lock(%s/%s, t=%x, fl=%x, r=%lld:%lld)\n", filp->f_path.dentry->d_parent->d_name.name, filp->f_path.dentry->d_name.name, 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_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); else if (fl->fl_type == F_UNLCK) ret = do_unlk(filp, cmd, fl); else ret = do_setlk(filp, cmd, fl); out_err: return ret; } /* * Lock a (portion of) a file */ static int nfs_flock(struct file *filp, int cmd, struct file_lock *fl) { dprintk("NFS: flock(%s/%s, t=%x, fl=%x)\n", filp->f_path.dentry->d_parent->d_name.name, filp->f_path.dentry->d_name.name, fl->fl_type, fl->fl_flags); if (!(fl->fl_flags & FL_FLOCK)) return -ENOLCK; /* We're simulating flock() locks using posix locks on the server */ fl->fl_owner = (fl_owner_t)filp; fl->fl_start = 0; fl->fl_end = OFFSET_MAX; if (fl->fl_type == F_UNLCK) return do_unlk(filp, cmd, fl); return do_setlk(filp, cmd, fl); } /* * There is no protocol support for leases, so we have no way to implement * them correctly in the face of opens by other clients. */ static int nfs_setlease(struct file *file, long arg, struct file_lock **fl) { dprintk("NFS: setlease(%s/%s, arg=%ld)\n", file->f_path.dentry->d_parent->d_name.name, file->f_path.dentry->d_name.name, arg); return -EINVAL; }