// SPDX-License-Identifier: GPL-2.0-only /* * 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 #include #include #include #include #include #include #include #include #include #include #include #include #include #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; 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); if (res == 0) filp->f_mode |= FMODE_CAN_ODIRECT; return res; } int nfs_file_release(struct inode *inode, struct file *filp) { dprintk("NFS: release(%pD2)\n", filp); nfs_inc_stats(inode, NFSIOS_VFSRELEASE); nfs_file_clear_open_context(filp); nfs_fscache_release_file(inode, filp); return 0; } EXPORT_SYMBOL_GPL(nfs_file_release); /** * nfs_revalidate_file_size - Revalidate the file size * @inode: pointer to inode struct * @filp: 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); if (filp->f_flags & O_DIRECT) goto force_reval; if (nfs_check_cache_invalid(inode, NFS_INO_INVALID_SIZE)) goto force_reval; 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. */ static int nfs_file_flush(struct file *file, fl_owner_t id) { struct inode *inode = file_inode(file); errseq_t since; dprintk("NFS: flush(%pD2)\n", file); nfs_inc_stats(inode, NFSIOS_VFSFLUSH); if ((file->f_mode & FMODE_WRITE) == 0) return 0; /* Flush writes to the server and return any errors */ since = filemap_sample_wb_err(file->f_mapping); nfs_wb_all(inode); return filemap_check_wb_err(file->f_mapping, since); } 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, false); dprintk("NFS: read(%pD2, %zu@%lu)\n", iocb->ki_filp, iov_iter_count(to), (unsigned long) iocb->ki_pos); nfs_start_io_read(inode); result = nfs_revalidate_mapping(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); } nfs_end_io_read(inode); return result; } EXPORT_SYMBOL_GPL(nfs_file_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. */ static int nfs_file_fsync_commit(struct file *file, int datasync) { struct inode *inode = file_inode(file); int ret, ret2; dprintk("NFS: fsync file(%pD2) datasync %d\n", file, datasync); nfs_inc_stats(inode, NFSIOS_VFSFSYNC); ret = nfs_commit_inode(inode, FLUSH_SYNC); ret2 = file_check_and_advance_wb_err(file); if (ret2 < 0) return ret2; return ret; } int nfs_file_fsync(struct file *file, loff_t start, loff_t end, int datasync) { struct inode *inode = file_inode(file); struct nfs_inode *nfsi = NFS_I(inode); long save_nredirtied = atomic_long_read(&nfsi->redirtied_pages); long nredirtied; int ret; trace_nfs_fsync_enter(inode); for (;;) { ret = file_write_and_wait_range(file, start, end); if (ret != 0) break; ret = nfs_file_fsync_commit(file, datasync); if (ret != 0) break; ret = pnfs_sync_inode(inode, !!datasync); if (ret != 0) break; nredirtied = atomic_long_read(&nfsi->redirtied_pages); if (nredirtied == save_nredirtied) break; save_nredirtied = nredirtied; } trace_nfs_fsync_exit(inode, ret); return ret; } EXPORT_SYMBOL_GPL(nfs_file_fsync); /* * 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. * * Some pNFS layout drivers can only read/write at a certain block * granularity like all block devices and therefore we must perform * read/modify/write whenever a page hasn't read yet and the data * to be written there is not aligned to a block boundary and/or * smaller than the block size. * * 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 bool nfs_folio_is_full_write(struct folio *folio, loff_t pos, unsigned int len) { unsigned int pglen = nfs_folio_length(folio); unsigned int offset = offset_in_folio(folio, pos); unsigned int end = offset + len; return !pglen || (end >= pglen && !offset); } static bool nfs_want_read_modify_write(struct file *file, struct folio *folio, loff_t pos, unsigned int len) { /* * Up-to-date pages, those with ongoing or full-page write * don't need read/modify/write */ if (folio_test_uptodate(folio) || folio_test_private(folio) || nfs_folio_is_full_write(folio, pos, len)) return false; if (pnfs_ld_read_whole_page(file_inode(file))) return true; /* Open for reading too? */ if (file->f_mode & FMODE_READ) return true; return false; } /* * 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, struct page **pagep, void **fsdata) { struct folio *folio; int once_thru = 0; int ret; dfprintk(PAGECACHE, "NFS: write_begin(%pD2(%lu), %u@%lld)\n", file, mapping->host->i_ino, len, (long long) pos); start: folio = __filemap_get_folio(mapping, pos >> PAGE_SHIFT, FGP_WRITEBEGIN, mapping_gfp_mask(mapping)); if (IS_ERR(folio)) return PTR_ERR(folio); *pagep = &folio->page; ret = nfs_flush_incompatible(file, folio); if (ret) { folio_unlock(folio); folio_put(folio); } else if (!once_thru && nfs_want_read_modify_write(file, folio, pos, len)) { once_thru = 1; ret = nfs_read_folio(file, folio); folio_put(folio); 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) { struct nfs_open_context *ctx = nfs_file_open_context(file); struct folio *folio = page_folio(page); unsigned offset = offset_in_folio(folio, pos); 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 (!folio_test_uptodate(folio)) { size_t fsize = folio_size(folio); unsigned pglen = nfs_folio_length(folio); unsigned end = offset + copied; if (pglen == 0) { folio_zero_segments(folio, 0, offset, end, fsize); folio_mark_uptodate(folio); } else if (end >= pglen) { folio_zero_segment(folio, end, fsize); if (offset == 0) folio_mark_uptodate(folio); } else folio_zero_segment(folio, pglen, fsize); } status = nfs_update_folio(file, folio, offset, copied); folio_unlock(folio); folio_put(folio); if (status < 0) return status; NFS_I(mapping->host)->write_io += copied; if (nfs_ctx_key_to_expire(ctx, mapping->host)) nfs_wb_all(mapping->host); 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_folio(struct folio *folio, size_t offset, size_t length) { struct inode *inode = folio_file_mapping(folio)->host; dfprintk(PAGECACHE, "NFS: invalidate_folio(%lu, %zu, %zu)\n", folio->index, offset, length); if (offset != 0 || length < folio_size(folio)) return; /* Cancel any unstarted writes on this page */ nfs_wb_folio_cancel(inode, folio); folio_wait_fscache(folio); trace_nfs_invalidate_folio(inode, folio); } /* * Attempt to release the private state associated with a folio * - Called if either private or fscache flags are set on the folio * - Caller holds folio lock * - Return true (may release folio) or false (may not) */ static bool nfs_release_folio(struct folio *folio, gfp_t gfp) { dfprintk(PAGECACHE, "NFS: release_folio(%p)\n", folio); /* If the private flag is set, then the folio is not freeable */ if (folio_test_private(folio)) { if ((current_gfp_context(gfp) & GFP_KERNEL) != GFP_KERNEL || current_is_kswapd()) return false; if (nfs_wb_folio(folio_file_mapping(folio)->host, folio) < 0) return false; } return nfs_fscache_release_folio(folio, gfp); } static void nfs_check_dirty_writeback(struct folio *folio, bool *dirty, bool *writeback) { struct nfs_inode *nfsi; struct address_space *mapping = folio->mapping; /* * Check if an unstable folio is currently being committed and * if so, have the VM treat it as if the folio is under writeback * so it will not block due to folios that will shortly be freeable. */ nfsi = NFS_I(mapping->host); if (atomic_read(&nfsi->commit_info.rpcs_out)) { *writeback = true; return; } /* * If the private flag is set, then the folio 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 (folio_test_private(folio)) *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_folio(struct folio *folio) { struct inode *inode = folio->mapping->host; int ret; dfprintk(PAGECACHE, "NFS: launder_folio(%ld, %llu)\n", inode->i_ino, folio_pos(folio)); folio_wait_fscache(folio); ret = nfs_wb_folio(inode, folio); trace_nfs_launder_folio_done(inode, folio, ret); return ret; } static int nfs_swap_activate(struct swap_info_struct *sis, struct file *file, sector_t *span) { unsigned long blocks; long long isize; int ret; struct inode *inode = file_inode(file); struct rpc_clnt *clnt = NFS_CLIENT(inode); struct nfs_client *cl = NFS_SERVER(inode)->nfs_client; spin_lock(&inode->i_lock); blocks = inode->i_blocks; isize = inode->i_size; spin_unlock(&inode->i_lock); if (blocks*512 < isize) { pr_warn("swap activate: swapfile has holes\n"); return -EINVAL; } ret = rpc_clnt_swap_activate(clnt); if (ret) return ret; ret = add_swap_extent(sis, 0, sis->max, 0); if (ret < 0) { rpc_clnt_swap_deactivate(clnt); return ret; } *span = sis->pages; if (cl->rpc_ops->enable_swap) cl->rpc_ops->enable_swap(inode); sis->flags |= SWP_FS_OPS; return ret; } static void nfs_swap_deactivate(struct file *file) { struct inode *inode = file_inode(file); struct rpc_clnt *clnt = NFS_CLIENT(inode); struct nfs_client *cl = NFS_SERVER(inode)->nfs_client; rpc_clnt_swap_deactivate(clnt); if (cl->rpc_ops->disable_swap) cl->rpc_ops->disable_swap(file_inode(file)); } const struct address_space_operations nfs_file_aops = { .read_folio = nfs_read_folio, .readahead = nfs_readahead, .dirty_folio = filemap_dirty_folio, .writepage = nfs_writepage, .writepages = nfs_writepages, .write_begin = nfs_write_begin, .write_end = nfs_write_end, .invalidate_folio = nfs_invalidate_folio, .release_folio = nfs_release_folio, .migrate_folio = nfs_migrate_folio, .launder_folio = nfs_launder_folio, .is_dirty_writeback = nfs_check_dirty_writeback, .error_remove_page = generic_error_remove_page, .swap_activate = nfs_swap_activate, .swap_deactivate = nfs_swap_deactivate, .swap_rw = nfs_swap_rw, }; /* * 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 vm_fault_t nfs_vm_page_mkwrite(struct vm_fault *vmf) { struct file *filp = vmf->vma->vm_file; struct inode *inode = file_inode(filp); unsigned pagelen; vm_fault_t ret = VM_FAULT_NOPAGE; struct address_space *mapping; struct folio *folio = page_folio(vmf->page); dfprintk(PAGECACHE, "NFS: vm_page_mkwrite(%pD2(%lu), offset %lld)\n", filp, filp->f_mapping->host->i_ino, (long long)folio_file_pos(folio)); sb_start_pagefault(inode->i_sb); /* make sure the cache has finished storing the page */ if (folio_test_fscache(folio) && folio_wait_fscache_killable(folio) < 0) { ret = VM_FAULT_RETRY; goto out; } wait_on_bit_action(&NFS_I(inode)->flags, NFS_INO_INVALIDATING, nfs_wait_bit_killable, TASK_KILLABLE|TASK_FREEZABLE_UNSAFE); folio_lock(folio); mapping = folio_file_mapping(folio); if (mapping != inode->i_mapping) goto out_unlock; folio_wait_writeback(folio); pagelen = nfs_folio_length(folio); if (pagelen == 0) goto out_unlock; ret = VM_FAULT_LOCKED; if (nfs_flush_incompatible(filp, folio) == 0 && nfs_update_folio(filp, folio, 0, pagelen) == 0) goto out; ret = VM_FAULT_SIGBUS; out_unlock: folio_unlock(folio); out: sb_end_pagefault(inode->i_sb); 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, }; 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 int mntflags = NFS_SERVER(inode)->flags; ssize_t result, written; errseq_t since; int error; result = nfs_key_timeout_notify(file, inode); if (result) return result; if (iocb->ki_flags & IOCB_DIRECT) return nfs_file_direct_write(iocb, from, false); dprintk("NFS: write(%pD2, %zu@%Ld)\n", file, iov_iter_count(from), (long long) iocb->ki_pos); if (IS_SWAPFILE(inode)) goto out_swapfile; /* * O_APPEND implies that we must revalidate the file length. */ if (iocb->ki_flags & IOCB_APPEND || iocb->ki_pos > i_size_read(inode)) { result = nfs_revalidate_file_size(inode, file); if (result) return result; } nfs_clear_invalid_mapping(file->f_mapping); since = filemap_sample_wb_err(file->f_mapping); nfs_start_io_write(inode); result = generic_write_checks(iocb, from); if (result > 0) result = generic_perform_write(iocb, from); nfs_end_io_write(inode); if (result <= 0) goto out; written = result; nfs_add_stats(inode, NFSIOS_NORMALWRITTENBYTES, written); if (mntflags & NFS_MOUNT_WRITE_EAGER) { result = filemap_fdatawrite_range(file->f_mapping, iocb->ki_pos - written, iocb->ki_pos - 1); if (result < 0) goto out; } if (mntflags & NFS_MOUNT_WRITE_WAIT) { filemap_fdatawait_range(file->f_mapping, iocb->ki_pos - written, iocb->ki_pos - 1); } result = generic_write_sync(iocb, written); if (result < 0) return result; out: /* Return error values */ error = filemap_check_wb_err(file->f_mapping, since); switch (error) { default: break; case -EDQUOT: case -EFBIG: case -ENOSPC: nfs_wb_all(inode); error = file_check_and_advance_wb_err(file); if (error < 0) result = error; } return result; out_swapfile: printk(KERN_INFO "NFS: attempt to write to active swap file!\n"); return -ETXTBSY; } 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_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.. */ nfs_wb_all(inode); l_ctx = nfs_get_lock_context(nfs_file_open_context(filp)); if (!IS_ERR(l_ctx)) { status = nfs_iocounter_wait(l_ctx); nfs_put_lock_context(l_ctx); /* NOTE: special case * If we're signalled while cleaning up locks on process exit, we * still need to complete the unlock. */ if (status < 0 && !(fl->fl_flags & FL_CLOSE)) return status; } /* * 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 = locks_lock_file_wait(filp, fl); return status; } 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 = locks_lock_file_wait(filp, fl); if (status < 0) goto out; /* * Invalidate cache to prevent missing any changes. If * the file is mapped, clear the page cache as well so * those mappings will be loaded. * * This makes locking act as a cache coherency point. */ nfs_sync_mapping(filp->f_mapping); if (!NFS_PROTO(inode)->have_delegation(inode, FMODE_READ)) { nfs_zap_caches(inode); if (mapping_mapped(filp->f_mapping)) nfs_revalidate_mapping(inode, filp->f_mapping); } 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); if (fl->fl_flags & FL_RECLAIM) return -ENOGRACE; 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; 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 = generic_file_splice_read, .splice_write = iter_file_splice_write, .check_flags = nfs_check_flags, .setlease = simple_nosetlease, }; EXPORT_SYMBOL_GPL(nfs_file_operations);