v4.19.13 snapshot.
diff --git a/fs/ramfs/Makefile b/fs/ramfs/Makefile
new file mode 100644
index 0000000..c71e65d
--- /dev/null
+++ b/fs/ramfs/Makefile
@@ -0,0 +1,9 @@
+#
+# Makefile for the linux ramfs routines.
+#
+
+obj-y += ramfs.o
+
+file-mmu-y := file-nommu.o
+file-mmu-$(CONFIG_MMU) := file-mmu.o
+ramfs-objs += inode.o $(file-mmu-y)
diff --git a/fs/ramfs/file-mmu.c b/fs/ramfs/file-mmu.c
new file mode 100644
index 0000000..12af049
--- /dev/null
+++ b/fs/ramfs/file-mmu.c
@@ -0,0 +1,55 @@
+/* file-mmu.c: ramfs MMU-based file operations
+ *
+ * Resizable simple ram filesystem for Linux.
+ *
+ * Copyright (C) 2000 Linus Torvalds.
+ * 2000 Transmeta Corp.
+ *
+ * Usage limits added by David Gibson, Linuxcare Australia.
+ * This file is released under the GPL.
+ */
+
+/*
+ * NOTE! This filesystem is probably most useful
+ * not as a real filesystem, but as an example of
+ * how virtual filesystems can be written.
+ *
+ * It doesn't get much simpler than this. Consider
+ * that this file implements the full semantics of
+ * a POSIX-compliant read-write filesystem.
+ *
+ * Note in particular how the filesystem does not
+ * need to implement any data structures of its own
+ * to keep track of the virtual data: using the VFS
+ * caches is sufficient.
+ */
+
+#include <linux/fs.h>
+#include <linux/mm.h>
+#include <linux/ramfs.h>
+#include <linux/sched.h>
+
+#include "internal.h"
+
+static unsigned long ramfs_mmu_get_unmapped_area(struct file *file,
+ unsigned long addr, unsigned long len, unsigned long pgoff,
+ unsigned long flags)
+{
+ return current->mm->get_unmapped_area(file, addr, len, pgoff, flags);
+}
+
+const struct file_operations ramfs_file_operations = {
+ .read_iter = generic_file_read_iter,
+ .write_iter = generic_file_write_iter,
+ .mmap = generic_file_mmap,
+ .fsync = noop_fsync,
+ .splice_read = generic_file_splice_read,
+ .splice_write = iter_file_splice_write,
+ .llseek = generic_file_llseek,
+ .get_unmapped_area = ramfs_mmu_get_unmapped_area,
+};
+
+const struct inode_operations ramfs_file_inode_operations = {
+ .setattr = simple_setattr,
+ .getattr = simple_getattr,
+};
diff --git a/fs/ramfs/file-nommu.c b/fs/ramfs/file-nommu.c
new file mode 100644
index 0000000..3ac1f23
--- /dev/null
+++ b/fs/ramfs/file-nommu.c
@@ -0,0 +1,268 @@
+/* file-nommu.c: no-MMU version of ramfs
+ *
+ * Copyright (C) 2005 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#include <linux/module.h>
+#include <linux/fs.h>
+#include <linux/mm.h>
+#include <linux/pagemap.h>
+#include <linux/highmem.h>
+#include <linux/init.h>
+#include <linux/string.h>
+#include <linux/backing-dev.h>
+#include <linux/ramfs.h>
+#include <linux/pagevec.h>
+#include <linux/mman.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+
+#include <linux/uaccess.h>
+#include "internal.h"
+
+static int ramfs_nommu_setattr(struct dentry *, struct iattr *);
+static unsigned long ramfs_nommu_get_unmapped_area(struct file *file,
+ unsigned long addr,
+ unsigned long len,
+ unsigned long pgoff,
+ unsigned long flags);
+static int ramfs_nommu_mmap(struct file *file, struct vm_area_struct *vma);
+
+static unsigned ramfs_mmap_capabilities(struct file *file)
+{
+ return NOMMU_MAP_DIRECT | NOMMU_MAP_COPY | NOMMU_MAP_READ |
+ NOMMU_MAP_WRITE | NOMMU_MAP_EXEC;
+}
+
+const struct file_operations ramfs_file_operations = {
+ .mmap_capabilities = ramfs_mmap_capabilities,
+ .mmap = ramfs_nommu_mmap,
+ .get_unmapped_area = ramfs_nommu_get_unmapped_area,
+ .read_iter = generic_file_read_iter,
+ .write_iter = generic_file_write_iter,
+ .fsync = noop_fsync,
+ .splice_read = generic_file_splice_read,
+ .splice_write = iter_file_splice_write,
+ .llseek = generic_file_llseek,
+};
+
+const struct inode_operations ramfs_file_inode_operations = {
+ .setattr = ramfs_nommu_setattr,
+ .getattr = simple_getattr,
+};
+
+/*****************************************************************************/
+/*
+ * add a contiguous set of pages into a ramfs inode when it's truncated from
+ * size 0 on the assumption that it's going to be used for an mmap of shared
+ * memory
+ */
+int ramfs_nommu_expand_for_mapping(struct inode *inode, size_t newsize)
+{
+ unsigned long npages, xpages, loop;
+ struct page *pages;
+ unsigned order;
+ void *data;
+ int ret;
+ gfp_t gfp = mapping_gfp_mask(inode->i_mapping);
+
+ /* make various checks */
+ order = get_order(newsize);
+ if (unlikely(order >= MAX_ORDER))
+ return -EFBIG;
+
+ ret = inode_newsize_ok(inode, newsize);
+ if (ret)
+ return ret;
+
+ i_size_write(inode, newsize);
+
+ /* allocate enough contiguous pages to be able to satisfy the
+ * request */
+ pages = alloc_pages(gfp, order);
+ if (!pages)
+ return -ENOMEM;
+
+ /* split the high-order page into an array of single pages */
+ xpages = 1UL << order;
+ npages = (newsize + PAGE_SIZE - 1) >> PAGE_SHIFT;
+
+ split_page(pages, order);
+
+ /* trim off any pages we don't actually require */
+ for (loop = npages; loop < xpages; loop++)
+ __free_page(pages + loop);
+
+ /* clear the memory we allocated */
+ newsize = PAGE_SIZE * npages;
+ data = page_address(pages);
+ memset(data, 0, newsize);
+
+ /* attach all the pages to the inode's address space */
+ for (loop = 0; loop < npages; loop++) {
+ struct page *page = pages + loop;
+
+ ret = add_to_page_cache_lru(page, inode->i_mapping, loop,
+ gfp);
+ if (ret < 0)
+ goto add_error;
+
+ /* prevent the page from being discarded on memory pressure */
+ SetPageDirty(page);
+ SetPageUptodate(page);
+
+ unlock_page(page);
+ put_page(page);
+ }
+
+ return 0;
+
+add_error:
+ while (loop < npages)
+ __free_page(pages + loop++);
+ return ret;
+}
+
+/*****************************************************************************/
+/*
+ *
+ */
+static int ramfs_nommu_resize(struct inode *inode, loff_t newsize, loff_t size)
+{
+ int ret;
+
+ /* assume a truncate from zero size is going to be for the purposes of
+ * shared mmap */
+ if (size == 0) {
+ if (unlikely(newsize >> 32))
+ return -EFBIG;
+
+ return ramfs_nommu_expand_for_mapping(inode, newsize);
+ }
+
+ /* check that a decrease in size doesn't cut off any shared mappings */
+ if (newsize < size) {
+ ret = nommu_shrink_inode_mappings(inode, size, newsize);
+ if (ret < 0)
+ return ret;
+ }
+
+ truncate_setsize(inode, newsize);
+ return 0;
+}
+
+/*****************************************************************************/
+/*
+ * handle a change of attributes
+ * - we're specifically interested in a change of size
+ */
+static int ramfs_nommu_setattr(struct dentry *dentry, struct iattr *ia)
+{
+ struct inode *inode = d_inode(dentry);
+ unsigned int old_ia_valid = ia->ia_valid;
+ int ret = 0;
+
+ /* POSIX UID/GID verification for setting inode attributes */
+ ret = setattr_prepare(dentry, ia);
+ if (ret)
+ return ret;
+
+ /* pick out size-changing events */
+ if (ia->ia_valid & ATTR_SIZE) {
+ loff_t size = inode->i_size;
+
+ if (ia->ia_size != size) {
+ ret = ramfs_nommu_resize(inode, ia->ia_size, size);
+ if (ret < 0 || ia->ia_valid == ATTR_SIZE)
+ goto out;
+ } else {
+ /* we skipped the truncate but must still update
+ * timestamps
+ */
+ ia->ia_valid |= ATTR_MTIME|ATTR_CTIME;
+ }
+ }
+
+ setattr_copy(inode, ia);
+ out:
+ ia->ia_valid = old_ia_valid;
+ return ret;
+}
+
+/*****************************************************************************/
+/*
+ * try to determine where a shared mapping can be made
+ * - we require that:
+ * - the pages to be mapped must exist
+ * - the pages be physically contiguous in sequence
+ */
+static unsigned long ramfs_nommu_get_unmapped_area(struct file *file,
+ unsigned long addr, unsigned long len,
+ unsigned long pgoff, unsigned long flags)
+{
+ unsigned long maxpages, lpages, nr, loop, ret;
+ struct inode *inode = file_inode(file);
+ struct page **pages = NULL, **ptr, *page;
+ loff_t isize;
+
+ /* the mapping mustn't extend beyond the EOF */
+ lpages = (len + PAGE_SIZE - 1) >> PAGE_SHIFT;
+ isize = i_size_read(inode);
+
+ ret = -ENOSYS;
+ maxpages = (isize + PAGE_SIZE - 1) >> PAGE_SHIFT;
+ if (pgoff >= maxpages)
+ goto out;
+
+ if (maxpages - pgoff < lpages)
+ goto out;
+
+ /* gang-find the pages */
+ pages = kcalloc(lpages, sizeof(struct page *), GFP_KERNEL);
+ if (!pages)
+ goto out_free;
+
+ nr = find_get_pages(inode->i_mapping, &pgoff, lpages, pages);
+ if (nr != lpages)
+ goto out_free_pages; /* leave if some pages were missing */
+
+ /* check the pages for physical adjacency */
+ ptr = pages;
+ page = *ptr++;
+ page++;
+ for (loop = lpages; loop > 1; loop--)
+ if (*ptr++ != page++)
+ goto out_free_pages;
+
+ /* okay - all conditions fulfilled */
+ ret = (unsigned long) page_address(pages[0]);
+
+out_free_pages:
+ ptr = pages;
+ for (loop = nr; loop > 0; loop--)
+ put_page(*ptr++);
+out_free:
+ kfree(pages);
+out:
+ return ret;
+}
+
+/*****************************************************************************/
+/*
+ * set up a mapping for shared memory segments
+ */
+static int ramfs_nommu_mmap(struct file *file, struct vm_area_struct *vma)
+{
+ if (!(vma->vm_flags & (VM_SHARED | VM_MAYSHARE)))
+ return -ENOSYS;
+
+ file_accessed(file);
+ vma->vm_ops = &generic_file_vm_ops;
+ return 0;
+}
diff --git a/fs/ramfs/inode.c b/fs/ramfs/inode.c
new file mode 100644
index 0000000..11201b2
--- /dev/null
+++ b/fs/ramfs/inode.c
@@ -0,0 +1,277 @@
+/*
+ * Resizable simple ram filesystem for Linux.
+ *
+ * Copyright (C) 2000 Linus Torvalds.
+ * 2000 Transmeta Corp.
+ *
+ * Usage limits added by David Gibson, Linuxcare Australia.
+ * This file is released under the GPL.
+ */
+
+/*
+ * NOTE! This filesystem is probably most useful
+ * not as a real filesystem, but as an example of
+ * how virtual filesystems can be written.
+ *
+ * It doesn't get much simpler than this. Consider
+ * that this file implements the full semantics of
+ * a POSIX-compliant read-write filesystem.
+ *
+ * Note in particular how the filesystem does not
+ * need to implement any data structures of its own
+ * to keep track of the virtual data: using the VFS
+ * caches is sufficient.
+ */
+
+#include <linux/fs.h>
+#include <linux/pagemap.h>
+#include <linux/highmem.h>
+#include <linux/time.h>
+#include <linux/init.h>
+#include <linux/string.h>
+#include <linux/backing-dev.h>
+#include <linux/ramfs.h>
+#include <linux/sched.h>
+#include <linux/parser.h>
+#include <linux/magic.h>
+#include <linux/slab.h>
+#include <linux/uaccess.h>
+#include "internal.h"
+
+struct ramfs_mount_opts {
+ umode_t mode;
+};
+
+struct ramfs_fs_info {
+ struct ramfs_mount_opts mount_opts;
+};
+
+#define RAMFS_DEFAULT_MODE 0755
+
+static const struct super_operations ramfs_ops;
+static const struct inode_operations ramfs_dir_inode_operations;
+
+static const struct address_space_operations ramfs_aops = {
+ .readpage = simple_readpage,
+ .write_begin = simple_write_begin,
+ .write_end = simple_write_end,
+ .set_page_dirty = __set_page_dirty_no_writeback,
+};
+
+struct inode *ramfs_get_inode(struct super_block *sb,
+ const struct inode *dir, umode_t mode, dev_t dev)
+{
+ struct inode * inode = new_inode(sb);
+
+ if (inode) {
+ inode->i_ino = get_next_ino();
+ inode_init_owner(inode, dir, mode);
+ inode->i_mapping->a_ops = &ramfs_aops;
+ mapping_set_gfp_mask(inode->i_mapping, GFP_HIGHUSER);
+ mapping_set_unevictable(inode->i_mapping);
+ inode->i_atime = inode->i_mtime = inode->i_ctime = current_time(inode);
+ switch (mode & S_IFMT) {
+ default:
+ init_special_inode(inode, mode, dev);
+ break;
+ case S_IFREG:
+ inode->i_op = &ramfs_file_inode_operations;
+ inode->i_fop = &ramfs_file_operations;
+ break;
+ case S_IFDIR:
+ inode->i_op = &ramfs_dir_inode_operations;
+ inode->i_fop = &simple_dir_operations;
+
+ /* directory inodes start off with i_nlink == 2 (for "." entry) */
+ inc_nlink(inode);
+ break;
+ case S_IFLNK:
+ inode->i_op = &page_symlink_inode_operations;
+ inode_nohighmem(inode);
+ break;
+ }
+ }
+ return inode;
+}
+
+/*
+ * File creation. Allocate an inode, and we're done..
+ */
+/* SMP-safe */
+static int
+ramfs_mknod(struct inode *dir, struct dentry *dentry, umode_t mode, dev_t dev)
+{
+ struct inode * inode = ramfs_get_inode(dir->i_sb, dir, mode, dev);
+ int error = -ENOSPC;
+
+ if (inode) {
+ d_instantiate(dentry, inode);
+ dget(dentry); /* Extra count - pin the dentry in core */
+ error = 0;
+ dir->i_mtime = dir->i_ctime = current_time(dir);
+ }
+ return error;
+}
+
+static int ramfs_mkdir(struct inode * dir, struct dentry * dentry, umode_t mode)
+{
+ int retval = ramfs_mknod(dir, dentry, mode | S_IFDIR, 0);
+ if (!retval)
+ inc_nlink(dir);
+ return retval;
+}
+
+static int ramfs_create(struct inode *dir, struct dentry *dentry, umode_t mode, bool excl)
+{
+ return ramfs_mknod(dir, dentry, mode | S_IFREG, 0);
+}
+
+static int ramfs_symlink(struct inode * dir, struct dentry *dentry, const char * symname)
+{
+ struct inode *inode;
+ int error = -ENOSPC;
+
+ inode = ramfs_get_inode(dir->i_sb, dir, S_IFLNK|S_IRWXUGO, 0);
+ if (inode) {
+ int l = strlen(symname)+1;
+ error = page_symlink(inode, symname, l);
+ if (!error) {
+ d_instantiate(dentry, inode);
+ dget(dentry);
+ dir->i_mtime = dir->i_ctime = current_time(dir);
+ } else
+ iput(inode);
+ }
+ return error;
+}
+
+static const struct inode_operations ramfs_dir_inode_operations = {
+ .create = ramfs_create,
+ .lookup = simple_lookup,
+ .link = simple_link,
+ .unlink = simple_unlink,
+ .symlink = ramfs_symlink,
+ .mkdir = ramfs_mkdir,
+ .rmdir = simple_rmdir,
+ .mknod = ramfs_mknod,
+ .rename = simple_rename,
+};
+
+/*
+ * Display the mount options in /proc/mounts.
+ */
+static int ramfs_show_options(struct seq_file *m, struct dentry *root)
+{
+ struct ramfs_fs_info *fsi = root->d_sb->s_fs_info;
+
+ if (fsi->mount_opts.mode != RAMFS_DEFAULT_MODE)
+ seq_printf(m, ",mode=%o", fsi->mount_opts.mode);
+ return 0;
+}
+
+static const struct super_operations ramfs_ops = {
+ .statfs = simple_statfs,
+ .drop_inode = generic_delete_inode,
+ .show_options = ramfs_show_options,
+};
+
+enum {
+ Opt_mode,
+ Opt_err
+};
+
+static const match_table_t tokens = {
+ {Opt_mode, "mode=%o"},
+ {Opt_err, NULL}
+};
+
+static int ramfs_parse_options(char *data, struct ramfs_mount_opts *opts)
+{
+ substring_t args[MAX_OPT_ARGS];
+ int option;
+ int token;
+ char *p;
+
+ opts->mode = RAMFS_DEFAULT_MODE;
+
+ while ((p = strsep(&data, ",")) != NULL) {
+ if (!*p)
+ continue;
+
+ token = match_token(p, tokens, args);
+ switch (token) {
+ case Opt_mode:
+ if (match_octal(&args[0], &option))
+ return -EINVAL;
+ opts->mode = option & S_IALLUGO;
+ break;
+ /*
+ * We might like to report bad mount options here;
+ * but traditionally ramfs has ignored all mount options,
+ * and as it is used as a !CONFIG_SHMEM simple substitute
+ * for tmpfs, better continue to ignore other mount options.
+ */
+ }
+ }
+
+ return 0;
+}
+
+int ramfs_fill_super(struct super_block *sb, void *data, int silent)
+{
+ struct ramfs_fs_info *fsi;
+ struct inode *inode;
+ int err;
+
+ fsi = kzalloc(sizeof(struct ramfs_fs_info), GFP_KERNEL);
+ sb->s_fs_info = fsi;
+ if (!fsi)
+ return -ENOMEM;
+
+ err = ramfs_parse_options(data, &fsi->mount_opts);
+ if (err)
+ return err;
+
+ sb->s_maxbytes = MAX_LFS_FILESIZE;
+ sb->s_blocksize = PAGE_SIZE;
+ sb->s_blocksize_bits = PAGE_SHIFT;
+ sb->s_magic = RAMFS_MAGIC;
+ sb->s_op = &ramfs_ops;
+ sb->s_time_gran = 1;
+
+ inode = ramfs_get_inode(sb, NULL, S_IFDIR | fsi->mount_opts.mode, 0);
+ sb->s_root = d_make_root(inode);
+ if (!sb->s_root)
+ return -ENOMEM;
+
+ return 0;
+}
+
+struct dentry *ramfs_mount(struct file_system_type *fs_type,
+ int flags, const char *dev_name, void *data)
+{
+ return mount_nodev(fs_type, flags, data, ramfs_fill_super);
+}
+
+static void ramfs_kill_sb(struct super_block *sb)
+{
+ kfree(sb->s_fs_info);
+ kill_litter_super(sb);
+}
+
+static struct file_system_type ramfs_fs_type = {
+ .name = "ramfs",
+ .mount = ramfs_mount,
+ .kill_sb = ramfs_kill_sb,
+ .fs_flags = FS_USERNS_MOUNT,
+};
+
+int __init init_ramfs_fs(void)
+{
+ static unsigned long once;
+
+ if (test_and_set_bit(0, &once))
+ return 0;
+ return register_filesystem(&ramfs_fs_type);
+}
+fs_initcall(init_ramfs_fs);
diff --git a/fs/ramfs/internal.h b/fs/ramfs/internal.h
new file mode 100644
index 0000000..a9d8ae8
--- /dev/null
+++ b/fs/ramfs/internal.h
@@ -0,0 +1,13 @@
+/* internal.h: ramfs internal definitions
+ *
+ * Copyright (C) 2005 Red Hat, Inc. All Rights Reserved.
+ * Written by David Howells (dhowells@redhat.com)
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+
+extern const struct inode_operations ramfs_file_inode_operations;