kernel: update yaffs code
[15.05/openwrt.git] / target / linux / generic / files / fs / yaffs2 / yaffs_vfs.c
diff --git a/target/linux/generic/files/fs/yaffs2/yaffs_vfs.c b/target/linux/generic/files/fs/yaffs2/yaffs_vfs.c
new file mode 100644 (file)
index 0000000..67050d4
--- /dev/null
@@ -0,0 +1,3462 @@
+/*
+ * YAFFS: Yet Another Flash File System. A NAND-flash specific file system.
+ *
+ * Copyright (C) 2002-2011 Aleph One Ltd.
+ *   for Toby Churchill Ltd and Brightstar Engineering
+ *
+ * Created by Charles Manning <charles@aleph1.co.uk>
+ * Acknowledgements:
+ * Luc van OostenRyck for numerous patches.
+ * Nick Bane for numerous patches.
+ * Nick Bane for 2.5/2.6 integration.
+ * Andras Toth for mknod rdev issue.
+ * Michael Fischer for finding the problem with inode inconsistency.
+ * Some code bodily lifted from JFFS
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+/*
+ *
+ * This is the file system front-end to YAFFS that hooks it up to
+ * the VFS.
+ *
+ * Special notes:
+ * >> 2.4: sb->u.generic_sbp points to the struct yaffs_dev associated with
+ *         this superblock
+ * >> 2.6: sb->s_fs_info  points to the struct yaffs_dev associated with this
+ *         superblock
+ * >> inode->u.generic_ip points to the associated struct yaffs_obj.
+ */
+
+/*
+ * There are two variants of the VFS glue code. This variant should compile
+ * for any version of Linux.
+ */
+#include <linux/version.h>
+
+#if (LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 10))
+#define YAFFS_COMPILE_BACKGROUND
+#if (LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 23))
+#define YAFFS_COMPILE_FREEZER
+#endif
+#endif
+
+#if (LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 28))
+#define YAFFS_COMPILE_EXPORTFS
+#endif
+
+#if (LINUX_VERSION_CODE > KERNEL_VERSION(2, 6, 35))
+#define YAFFS_USE_SETATTR_COPY
+#define YAFFS_USE_TRUNCATE_SETSIZE
+#endif
+#if (LINUX_VERSION_CODE > KERNEL_VERSION(2, 6, 35))
+#define YAFFS_HAS_EVICT_INODE
+#endif
+
+#if (LINUX_VERSION_CODE > KERNEL_VERSION(2, 6, 13))
+#define YAFFS_NEW_FOLLOW_LINK 1
+#else
+#define YAFFS_NEW_FOLLOW_LINK 0
+#endif
+
+#if (LINUX_VERSION_CODE < KERNEL_VERSION(3, 6, 0))
+#define YAFFS_HAS_WRITE_SUPER
+#endif
+
+
+#if (LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 19))
+#include <linux/config.h>
+#endif
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/init.h>
+#include <linux/fs.h>
+#include <linux/proc_fs.h>
+#if (LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 39))
+#include <linux/smp_lock.h>
+#endif
+#include <linux/pagemap.h>
+#include <linux/mtd/mtd.h>
+#include <linux/interrupt.h>
+#include <linux/string.h>
+#include <linux/ctype.h>
+
+#if (YAFFS_NEW_FOLLOW_LINK == 1)
+#include <linux/namei.h>
+#endif
+
+#ifdef YAFFS_COMPILE_EXPORTFS
+#include <linux/exportfs.h>
+#endif
+
+#ifdef YAFFS_COMPILE_BACKGROUND
+#include <linux/kthread.h>
+#include <linux/delay.h>
+#endif
+#ifdef YAFFS_COMPILE_FREEZER
+#include <linux/freezer.h>
+#endif
+
+#include <asm/div64.h>
+
+#if (LINUX_VERSION_CODE > KERNEL_VERSION(2, 5, 0))
+
+#include <linux/statfs.h>
+
+#define UnlockPage(p) unlock_page(p)
+#define Page_Uptodate(page)    test_bit(PG_uptodate, &(page)->flags)
+
+/* FIXME: use sb->s_id instead ? */
+#define yaffs_devname(sb, buf) bdevname(sb->s_bdev, buf)
+
+#else
+
+#include <linux/locks.h>
+#define        BDEVNAME_SIZE           0
+#define        yaffs_devname(sb, buf)  kdevname(sb->s_dev)
+
+#if (LINUX_VERSION_CODE < KERNEL_VERSION(2, 5, 0))
+/* added NCB 26/5/2006 for 2.4.25-vrs2-tcl1 kernel */
+#define __user
+#endif
+
+#endif
+
+#if (LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 26))
+#define YPROC_ROOT  (&proc_root)
+#else
+#define YPROC_ROOT  NULL
+#endif
+
+#if (LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 26))
+#define Y_INIT_TIMER(a)        init_timer(a)
+#else
+#define Y_INIT_TIMER(a)        init_timer_on_stack(a)
+#endif
+
+#if (LINUX_VERSION_CODE > KERNEL_VERSION(2, 6, 27))
+#define YAFFS_USE_WRITE_BEGIN_END 1
+#else
+#define YAFFS_USE_WRITE_BEGIN_END 0
+#endif
+
+#if (LINUX_VERSION_CODE < KERNEL_VERSION(3, 6, 0))
+#define YAFFS_SUPER_HAS_DIRTY
+#endif
+
+
+#if (LINUX_VERSION_CODE < KERNEL_VERSION(3, 2, 0))
+#define set_nlink(inode, count)  do { (inode)->i_nlink = (count); } while(0)
+#endif
+
+#if (LINUX_VERSION_CODE > KERNEL_VERSION(2, 6, 28))
+static uint32_t YCALCBLOCKS(uint64_t partition_size, uint32_t block_size)
+{
+       uint64_t result = partition_size;
+       do_div(result, block_size);
+       return (uint32_t) result;
+}
+#else
+#define YCALCBLOCKS(s, b) ((s)/(b))
+#endif
+
+#include <linux/uaccess.h>
+#include <linux/mtd/mtd.h>
+
+#include "yportenv.h"
+#include "yaffs_trace.h"
+#include "yaffs_guts.h"
+#include "yaffs_attribs.h"
+
+#include "yaffs_linux.h"
+
+#include "yaffs_mtdif.h"
+#include "yaffs_packedtags2.h"
+#include "yaffs_getblockinfo.h"
+
+unsigned int yaffs_trace_mask =
+               YAFFS_TRACE_BAD_BLOCKS |
+               YAFFS_TRACE_ALWAYS |
+               0;
+
+unsigned int yaffs_wr_attempts = YAFFS_WR_ATTEMPTS;
+unsigned int yaffs_auto_checkpoint = 1;
+unsigned int yaffs_gc_control = 1;
+unsigned int yaffs_bg_enable = 1;
+unsigned int yaffs_auto_select = 1;
+/* Module Parameters */
+#if (LINUX_VERSION_CODE > KERNEL_VERSION(2, 5, 0))
+module_param(yaffs_trace_mask, uint, 0644);
+module_param(yaffs_wr_attempts, uint, 0644);
+module_param(yaffs_auto_checkpoint, uint, 0644);
+module_param(yaffs_gc_control, uint, 0644);
+module_param(yaffs_bg_enable, uint, 0644);
+#else
+MODULE_PARM(yaffs_trace_mask, "i");
+MODULE_PARM(yaffs_wr_attempts, "i");
+MODULE_PARM(yaffs_auto_checkpoint, "i");
+MODULE_PARM(yaffs_gc_control, "i");
+#endif
+
+#if (LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 25))
+/* use iget and read_inode */
+#define Y_IGET(sb, inum) iget((sb), (inum))
+
+#else
+/* Call local equivalent */
+#define YAFFS_USE_OWN_IGET
+#define Y_IGET(sb, inum) yaffs_iget((sb), (inum))
+
+#endif
+
+#if (LINUX_VERSION_CODE > KERNEL_VERSION(2, 6, 18))
+#define yaffs_inode_to_obj_lv(iptr) ((iptr)->i_private)
+#else
+#define yaffs_inode_to_obj_lv(iptr) ((iptr)->u.generic_ip)
+#endif
+
+#define yaffs_inode_to_obj(iptr) \
+       ((struct yaffs_obj *)(yaffs_inode_to_obj_lv(iptr)))
+#define yaffs_dentry_to_obj(dptr) yaffs_inode_to_obj((dptr)->d_inode)
+
+#if (LINUX_VERSION_CODE > KERNEL_VERSION(2, 5, 0))
+#define yaffs_super_to_dev(sb) ((struct yaffs_dev *)sb->s_fs_info)
+#else
+#define yaffs_super_to_dev(sb) ((struct yaffs_dev *)sb->u.generic_sbp)
+#endif
+
+#if (LINUX_VERSION_CODE >= KERNEL_VERSION(3, 5, 0))
+#define Y_CLEAR_INODE(i) clear_inode(i)
+#else
+#define Y_CLEAR_INODE(i) end_writeback(i)
+#endif
+
+
+#define update_dir_time(dir) do {\
+                       (dir)->i_ctime = (dir)->i_mtime = CURRENT_TIME; \
+               } while (0)
+
+static void yaffs_fill_inode_from_obj(struct inode *inode,
+                                     struct yaffs_obj *obj);
+
+
+static void yaffs_gross_lock(struct yaffs_dev *dev)
+{
+       yaffs_trace(YAFFS_TRACE_LOCK, "yaffs locking %p", current);
+       mutex_lock(&(yaffs_dev_to_lc(dev)->gross_lock));
+       yaffs_trace(YAFFS_TRACE_LOCK, "yaffs locked %p", current);
+}
+
+static void yaffs_gross_unlock(struct yaffs_dev *dev)
+{
+       yaffs_trace(YAFFS_TRACE_LOCK, "yaffs unlocking %p", current);
+       mutex_unlock(&(yaffs_dev_to_lc(dev)->gross_lock));
+}
+
+
+static int yaffs_readpage_nolock(struct file *f, struct page *pg)
+{
+       /* Lifted from jffs2 */
+
+       struct yaffs_obj *obj;
+       unsigned char *pg_buf;
+       int ret;
+       loff_t pos = ((loff_t) pg->index) << PAGE_CACHE_SHIFT;
+       struct yaffs_dev *dev;
+
+       yaffs_trace(YAFFS_TRACE_OS,
+               "yaffs_readpage_nolock at %lld, size %08x",
+               (long long)pos,
+               (unsigned)PAGE_CACHE_SIZE);
+
+       obj = yaffs_dentry_to_obj(f->f_dentry);
+
+       dev = obj->my_dev;
+
+#if (LINUX_VERSION_CODE > KERNEL_VERSION(2, 5, 0))
+       BUG_ON(!PageLocked(pg));
+#else
+       if (!PageLocked(pg))
+               PAGE_BUG(pg);
+#endif
+
+       pg_buf = kmap(pg);
+       /* FIXME: Can kmap fail? */
+
+       yaffs_gross_lock(dev);
+
+       ret = yaffs_file_rd(obj, pg_buf, pos, PAGE_CACHE_SIZE);
+
+       yaffs_gross_unlock(dev);
+
+       if (ret >= 0)
+               ret = 0;
+
+       if (ret) {
+               ClearPageUptodate(pg);
+               SetPageError(pg);
+       } else {
+               SetPageUptodate(pg);
+               ClearPageError(pg);
+       }
+
+       flush_dcache_page(pg);
+       kunmap(pg);
+
+       yaffs_trace(YAFFS_TRACE_OS, "yaffs_readpage_nolock done");
+       return ret;
+}
+
+static int yaffs_readpage_unlock(struct file *f, struct page *pg)
+{
+       int ret = yaffs_readpage_nolock(f, pg);
+       UnlockPage(pg);
+       return ret;
+}
+
+static int yaffs_readpage(struct file *f, struct page *pg)
+{
+       int ret;
+
+       yaffs_trace(YAFFS_TRACE_OS, "yaffs_readpage");
+       ret = yaffs_readpage_unlock(f, pg);
+       yaffs_trace(YAFFS_TRACE_OS, "yaffs_readpage done");
+       return ret;
+}
+
+
+static void yaffs_set_super_dirty_val(struct yaffs_dev *dev, int val)
+{
+       struct yaffs_linux_context *lc = yaffs_dev_to_lc(dev);
+
+       if (lc)
+               lc->dirty = val;
+
+# ifdef YAFFS_SUPER_HAS_DIRTY
+       {
+               struct super_block *sb = lc->super;
+
+               if (sb)
+                       sb->s_dirt = val;
+       }
+#endif
+
+}
+
+static void yaffs_set_super_dirty(struct yaffs_dev *dev)
+{
+       yaffs_set_super_dirty_val(dev, 1);
+}
+
+static void yaffs_clear_super_dirty(struct yaffs_dev *dev)
+{
+       yaffs_set_super_dirty_val(dev, 0);
+}
+
+static int yaffs_check_super_dirty(struct yaffs_dev *dev)
+{
+       struct yaffs_linux_context *lc = yaffs_dev_to_lc(dev);
+
+       if (lc && lc->dirty)
+               return 1;
+
+# ifdef YAFFS_SUPER_HAS_DIRTY
+       {
+               struct super_block *sb = lc->super;
+
+               if (sb && sb->s_dirt)
+                       return 1;
+       }
+#endif
+       return 0;
+
+}
+
+#if (LINUX_VERSION_CODE > KERNEL_VERSION(2, 5, 0))
+static int yaffs_writepage(struct page *page, struct writeback_control *wbc)
+#else
+static int yaffs_writepage(struct page *page)
+#endif
+{
+       struct yaffs_dev *dev;
+       struct address_space *mapping = page->mapping;
+       struct inode *inode;
+       unsigned long end_index;
+       char *buffer;
+       struct yaffs_obj *obj;
+       int n_written = 0;
+       unsigned n_bytes;
+       loff_t i_size;
+
+       if (!mapping)
+               BUG();
+       inode = mapping->host;
+       if (!inode)
+               BUG();
+       i_size = i_size_read(inode);
+
+       end_index = i_size >> PAGE_CACHE_SHIFT;
+
+       if (page->index < end_index)
+               n_bytes = PAGE_CACHE_SIZE;
+       else {
+               n_bytes = i_size & (PAGE_CACHE_SIZE - 1);
+
+               if (page->index > end_index || !n_bytes) {
+                       yaffs_trace(YAFFS_TRACE_OS,
+                               "yaffs_writepage at %lld, inode size = %lld!!",
+                               ((loff_t)page->index) << PAGE_CACHE_SHIFT,
+                               inode->i_size);
+                       yaffs_trace(YAFFS_TRACE_OS,
+                               "                -> don't care!!");
+
+                       zero_user_segment(page, 0, PAGE_CACHE_SIZE);
+                       set_page_writeback(page);
+                       unlock_page(page);
+                       end_page_writeback(page);
+                       return 0;
+               }
+       }
+
+       if (n_bytes != PAGE_CACHE_SIZE)
+               zero_user_segment(page, n_bytes, PAGE_CACHE_SIZE);
+
+       get_page(page);
+
+       buffer = kmap(page);
+
+       obj = yaffs_inode_to_obj(inode);
+       dev = obj->my_dev;
+       yaffs_gross_lock(dev);
+
+       yaffs_trace(YAFFS_TRACE_OS,
+               "yaffs_writepage at %lld, size %08x",
+               ((loff_t)page->index) << PAGE_CACHE_SHIFT, n_bytes);
+       yaffs_trace(YAFFS_TRACE_OS,
+               "writepag0: obj = %lld, ino = %lld",
+               obj->variant.file_variant.file_size, inode->i_size);
+
+       n_written = yaffs_wr_file(obj, buffer,
+                                 ((loff_t)page->index) << PAGE_CACHE_SHIFT, n_bytes, 0);
+
+       yaffs_set_super_dirty(dev);
+
+       yaffs_trace(YAFFS_TRACE_OS,
+               "writepag1: obj = %lld, ino = %lld",
+               obj->variant.file_variant.file_size, inode->i_size);
+
+       yaffs_gross_unlock(dev);
+
+       kunmap(page);
+       set_page_writeback(page);
+       unlock_page(page);
+       end_page_writeback(page);
+       put_page(page);
+
+       return (n_written == n_bytes) ? 0 : -ENOSPC;
+}
+
+/* Space holding and freeing is done to ensure we have space available for write_begin/end */
+/* For now we just assume few parallel writes and check against a small number. */
+/* Todo: need to do this with a counter to handle parallel reads better */
+
+static ssize_t yaffs_hold_space(struct file *f)
+{
+       struct yaffs_obj *obj;
+       struct yaffs_dev *dev;
+
+       int n_free_chunks;
+
+       obj = yaffs_dentry_to_obj(f->f_dentry);
+
+       dev = obj->my_dev;
+
+       yaffs_gross_lock(dev);
+
+       n_free_chunks = yaffs_get_n_free_chunks(dev);
+
+       yaffs_gross_unlock(dev);
+
+       return (n_free_chunks > 20) ? 1 : 0;
+}
+
+static void yaffs_release_space(struct file *f)
+{
+       struct yaffs_obj *obj;
+       struct yaffs_dev *dev;
+
+       obj = yaffs_dentry_to_obj(f->f_dentry);
+
+       dev = obj->my_dev;
+
+       yaffs_gross_lock(dev);
+
+       yaffs_gross_unlock(dev);
+}
+
+#if (YAFFS_USE_WRITE_BEGIN_END > 0)
+static int yaffs_write_begin(struct file *filp, struct address_space *mapping,
+                            loff_t pos, unsigned len, unsigned flags,
+                            struct page **pagep, void **fsdata)
+{
+       struct page *pg = NULL;
+       pgoff_t index = pos >> PAGE_CACHE_SHIFT;
+
+       int ret = 0;
+       int space_held = 0;
+
+       /* Get a page */
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 28)
+       pg = grab_cache_page_write_begin(mapping, index, flags);
+#else
+       pg = __grab_cache_page(mapping, index);
+#endif
+
+       *pagep = pg;
+       if (!pg) {
+               ret = -ENOMEM;
+               goto out;
+       }
+       yaffs_trace(YAFFS_TRACE_OS,
+               "start yaffs_write_begin index %d(%x) uptodate %d",
+               (int)index, (int)index, Page_Uptodate(pg) ? 1 : 0);
+
+       /* Get fs space */
+       space_held = yaffs_hold_space(filp);
+
+       if (!space_held) {
+               ret = -ENOSPC;
+               goto out;
+       }
+
+       /* Update page if required */
+
+       if (!Page_Uptodate(pg))
+               ret = yaffs_readpage_nolock(filp, pg);
+
+       if (ret)
+               goto out;
+
+       /* Happy path return */
+       yaffs_trace(YAFFS_TRACE_OS, "end yaffs_write_begin - ok");
+
+       return 0;
+
+out:
+       yaffs_trace(YAFFS_TRACE_OS,
+               "end yaffs_write_begin fail returning %d", ret);
+       if (space_held)
+               yaffs_release_space(filp);
+       if (pg) {
+               unlock_page(pg);
+               page_cache_release(pg);
+       }
+       return ret;
+}
+
+#else
+
+static int yaffs_prepare_write(struct file *f, struct page *pg,
+                              unsigned offset, unsigned to)
+{
+       yaffs_trace(YAFFS_TRACE_OS, "yaffs_prepair_write");
+
+       if (!Page_Uptodate(pg))
+               return yaffs_readpage_nolock(f, pg);
+       return 0;
+}
+#endif
+
+
+static ssize_t yaffs_file_write(struct file *f, const char *buf, size_t n,
+                               loff_t * pos)
+{
+       struct yaffs_obj *obj;
+       int n_written;
+       loff_t ipos;
+       struct inode *inode;
+       struct yaffs_dev *dev;
+
+       obj = yaffs_dentry_to_obj(f->f_dentry);
+
+       if (!obj) {
+               yaffs_trace(YAFFS_TRACE_OS,
+                       "yaffs_file_write: hey obj is null!");
+                return -EINVAL;
+        }
+
+       dev = obj->my_dev;
+
+       yaffs_gross_lock(dev);
+
+       inode = f->f_dentry->d_inode;
+
+       if (!S_ISBLK(inode->i_mode) && f->f_flags & O_APPEND)
+               ipos = inode->i_size;
+       else
+               ipos = *pos;
+
+       yaffs_trace(YAFFS_TRACE_OS,
+               "yaffs_file_write about to write writing %u(%x) bytes to object %d at %lld",
+               (unsigned)n, (unsigned)n, obj->obj_id, ipos);
+
+       n_written = yaffs_wr_file(obj, buf, ipos, n, 0);
+
+       yaffs_set_super_dirty(dev);
+
+       yaffs_trace(YAFFS_TRACE_OS,
+               "yaffs_file_write: %d(%x) bytes written",
+               (unsigned)n, (unsigned)n);
+
+       if (n_written > 0) {
+               ipos += n_written;
+               *pos = ipos;
+               if (ipos > inode->i_size) {
+                       inode->i_size = ipos;
+                       inode->i_blocks = (ipos + 511) >> 9;
+
+                       yaffs_trace(YAFFS_TRACE_OS,
+                               "yaffs_file_write size updated to %lld bytes, %d blocks",
+                               ipos, (int)(inode->i_blocks));
+               }
+
+       }
+       yaffs_gross_unlock(dev);
+       return (n_written == 0) && (n > 0) ? -ENOSPC : n_written;
+}
+
+
+#if (YAFFS_USE_WRITE_BEGIN_END > 0)
+static int yaffs_write_end(struct file *filp, struct address_space *mapping,
+                          loff_t pos, unsigned len, unsigned copied,
+                          struct page *pg, void *fsdadata)
+{
+       int ret = 0;
+       void *addr, *kva;
+       uint32_t offset_into_page = pos & (PAGE_CACHE_SIZE - 1);
+
+       kva = kmap(pg);
+       addr = kva + offset_into_page;
+
+       yaffs_trace(YAFFS_TRACE_OS,
+               "yaffs_write_end addr %p pos %lld n_bytes %d",
+               addr, pos, copied);
+
+       ret = yaffs_file_write(filp, addr, copied, &pos);
+
+       if (ret != copied) {
+               yaffs_trace(YAFFS_TRACE_OS,
+                       "yaffs_write_end not same size ret %d  copied %d",
+                       ret, copied);
+               SetPageError(pg);
+       }
+
+       kunmap(pg);
+
+       yaffs_release_space(filp);
+       unlock_page(pg);
+       page_cache_release(pg);
+       return ret;
+}
+#else
+
+static int yaffs_commit_write(struct file *f, struct page *pg, unsigned offset,
+                             unsigned to)
+{
+       void *addr, *kva;
+
+       loff_t pos = (((loff_t) pg->index) << PAGE_CACHE_SHIFT) + offset;
+       int n_bytes = to - offset;
+       int n_written;
+
+       kva = kmap(pg);
+       addr = kva + offset;
+
+       yaffs_trace(YAFFS_TRACE_OS,
+               "yaffs_commit_write addr %p pos %lld n_bytes %d",
+               addr, pos, n_bytes);
+
+       n_written = yaffs_file_write(f, addr, n_bytes, &pos);
+
+       if (n_written != n_bytes) {
+               yaffs_trace(YAFFS_TRACE_OS,
+                       "yaffs_commit_write not same size n_written %d  n_bytes %d",
+                       n_written, n_bytes);
+               SetPageError(pg);
+       }
+       kunmap(pg);
+
+       yaffs_trace(YAFFS_TRACE_OS,
+               "yaffs_commit_write returning %d",
+               n_written == n_bytes ? 0 : n_written);
+
+       return n_written == n_bytes ? 0 : n_written;
+}
+#endif
+
+static struct address_space_operations yaffs_file_address_operations = {
+       .readpage = yaffs_readpage,
+       .writepage = yaffs_writepage,
+#if (YAFFS_USE_WRITE_BEGIN_END > 0)
+       .write_begin = yaffs_write_begin,
+       .write_end = yaffs_write_end,
+#else
+       .prepare_write = yaffs_prepare_write,
+       .commit_write = yaffs_commit_write,
+#endif
+};
+
+
+#if (LINUX_VERSION_CODE > KERNEL_VERSION(2, 6, 17))
+static int yaffs_file_flush(struct file *file, fl_owner_t id)
+#else
+static int yaffs_file_flush(struct file *file)
+#endif
+{
+       struct yaffs_obj *obj = yaffs_dentry_to_obj(file->f_dentry);
+
+       struct yaffs_dev *dev = obj->my_dev;
+
+       yaffs_trace(YAFFS_TRACE_OS,
+               "yaffs_file_flush object %d (%s)",
+               obj->obj_id,
+               obj->dirty ? "dirty" : "clean");
+
+       yaffs_gross_lock(dev);
+
+       yaffs_flush_file(obj, 1, 0);
+
+       yaffs_gross_unlock(dev);
+
+       return 0;
+}
+
+
+#if (LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 39))
+static int yaffs_sync_object(struct file *file, loff_t start, loff_t end, int datasync)
+#elif (LINUX_VERSION_CODE > KERNEL_VERSION(2, 6, 34))
+static int yaffs_sync_object(struct file *file, int datasync)
+#else
+static int yaffs_sync_object(struct file *file, struct dentry *dentry,
+                            int datasync)
+#endif
+{
+       struct yaffs_obj *obj;
+       struct yaffs_dev *dev;
+#if (LINUX_VERSION_CODE > KERNEL_VERSION(2, 6, 34))
+       struct dentry *dentry = file->f_path.dentry;
+#endif
+
+       obj = yaffs_dentry_to_obj(dentry);
+
+       dev = obj->my_dev;
+
+       yaffs_trace(YAFFS_TRACE_OS | YAFFS_TRACE_SYNC,
+               "yaffs_sync_object");
+       yaffs_gross_lock(dev);
+       yaffs_flush_file(obj, 1, datasync);
+       yaffs_gross_unlock(dev);
+       return 0;
+}
+
+
+#if (LINUX_VERSION_CODE > KERNEL_VERSION(2, 6, 22))
+static const struct file_operations yaffs_file_operations = {
+       .read = do_sync_read,
+       .write = do_sync_write,
+       .aio_read = generic_file_aio_read,
+       .aio_write = generic_file_aio_write,
+       .mmap = generic_file_mmap,
+       .flush = yaffs_file_flush,
+       .fsync = yaffs_sync_object,
+       .splice_read = generic_file_splice_read,
+       .splice_write = generic_file_splice_write,
+       .llseek = generic_file_llseek,
+};
+
+#elif (LINUX_VERSION_CODE > KERNEL_VERSION(2, 6, 18))
+
+static const struct file_operations yaffs_file_operations = {
+       .read = do_sync_read,
+       .write = do_sync_write,
+       .aio_read = generic_file_aio_read,
+       .aio_write = generic_file_aio_write,
+       .mmap = generic_file_mmap,
+       .flush = yaffs_file_flush,
+       .fsync = yaffs_sync_object,
+       .sendfile = generic_file_sendfile,
+};
+
+#else
+
+static const struct file_operations yaffs_file_operations = {
+       .read = generic_file_read,
+       .write = generic_file_write,
+       .mmap = generic_file_mmap,
+       .flush = yaffs_file_flush,
+       .fsync = yaffs_sync_object,
+#if (LINUX_VERSION_CODE > KERNEL_VERSION(2, 5, 0))
+       .sendfile = generic_file_sendfile,
+#endif
+};
+#endif
+
+
+
+
+#if (LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 25))
+static void zero_user_segment(struct page *page, unsigned start, unsigned end)
+{
+       void *kaddr = kmap_atomic(page, KM_USER0);
+       memset(kaddr + start, 0, end - start);
+       kunmap_atomic(kaddr, KM_USER0);
+       flush_dcache_page(page);
+}
+#endif
+
+
+static int yaffs_vfs_setsize(struct inode *inode, loff_t newsize)
+{
+#ifdef YAFFS_USE_TRUNCATE_SETSIZE
+       truncate_setsize(inode, newsize);
+       return 0;
+#else
+       truncate_inode_pages(&inode->i_data, newsize);
+       return 0;
+#endif
+
+}
+
+
+static int yaffs_vfs_setattr(struct inode *inode, struct iattr *attr)
+{
+#ifdef YAFFS_USE_SETATTR_COPY
+       setattr_copy(inode, attr);
+       return 0;
+#else
+       return inode_setattr(inode, attr);
+#endif
+
+}
+
+static int yaffs_setattr(struct dentry *dentry, struct iattr *attr)
+{
+       struct inode *inode = dentry->d_inode;
+       int error = 0;
+       struct yaffs_dev *dev;
+
+       yaffs_trace(YAFFS_TRACE_OS,
+               "yaffs_setattr of object %d",
+               yaffs_inode_to_obj(inode)->obj_id);
+#if 0
+       /* Fail if a requested resize >= 2GB */
+       if (attr->ia_valid & ATTR_SIZE && (attr->ia_size >> 31))
+               error = -EINVAL;
+#endif
+
+       if (error == 0)
+               error = inode_change_ok(inode, attr);
+       if (error == 0) {
+               int result;
+               if (!error) {
+                       error = yaffs_vfs_setattr(inode, attr);
+                       yaffs_trace(YAFFS_TRACE_OS, "inode_setattr called");
+                       if (attr->ia_valid & ATTR_SIZE) {
+                               yaffs_vfs_setsize(inode, attr->ia_size);
+                               inode->i_blocks = (inode->i_size + 511) >> 9;
+                       }
+               }
+               dev = yaffs_inode_to_obj(inode)->my_dev;
+               if (attr->ia_valid & ATTR_SIZE) {
+                       yaffs_trace(YAFFS_TRACE_OS,
+                               "resize to %d(%x)",
+                               (int)(attr->ia_size),
+                               (int)(attr->ia_size));
+               }
+               yaffs_gross_lock(dev);
+               result = yaffs_set_attribs(yaffs_inode_to_obj(inode), attr);
+               if (result == YAFFS_OK) {
+                       error = 0;
+               } else {
+                       error = -EPERM;
+               }
+               yaffs_gross_unlock(dev);
+
+       }
+
+       yaffs_trace(YAFFS_TRACE_OS, "yaffs_setattr done returning %d", error);
+
+       return error;
+}
+
+static int yaffs_setxattr(struct dentry *dentry, const char *name,
+                  const void *value, size_t size, int flags)
+{
+       struct inode *inode = dentry->d_inode;
+       int error = 0;
+       struct yaffs_dev *dev;
+       struct yaffs_obj *obj = yaffs_inode_to_obj(inode);
+
+       yaffs_trace(YAFFS_TRACE_OS, "yaffs_setxattr of object %d", obj->obj_id);
+
+       if (error == 0) {
+               int result;
+               dev = obj->my_dev;
+               yaffs_gross_lock(dev);
+               result = yaffs_set_xattrib(obj, name, value, size, flags);
+               if (result == YAFFS_OK)
+                       error = 0;
+               else if (result < 0)
+                       error = result;
+               yaffs_gross_unlock(dev);
+
+       }
+       yaffs_trace(YAFFS_TRACE_OS, "yaffs_setxattr done returning %d", error);
+
+       return error;
+}
+
+static ssize_t yaffs_getxattr(struct dentry * dentry, const char *name,
+                       void *buff, size_t size)
+{
+       struct inode *inode = dentry->d_inode;
+       int error = 0;
+       struct yaffs_dev *dev;
+       struct yaffs_obj *obj = yaffs_inode_to_obj(inode);
+
+       yaffs_trace(YAFFS_TRACE_OS,
+               "yaffs_getxattr \"%s\" from object %d",
+               name, obj->obj_id);
+
+       if (error == 0) {
+               dev = obj->my_dev;
+               yaffs_gross_lock(dev);
+               error = yaffs_get_xattrib(obj, name, buff, size);
+               yaffs_gross_unlock(dev);
+
+       }
+       yaffs_trace(YAFFS_TRACE_OS, "yaffs_getxattr done returning %d", error);
+
+       return error;
+}
+
+static int yaffs_removexattr(struct dentry *dentry, const char *name)
+{
+       struct inode *inode = dentry->d_inode;
+       int error = 0;
+       struct yaffs_dev *dev;
+       struct yaffs_obj *obj = yaffs_inode_to_obj(inode);
+
+       yaffs_trace(YAFFS_TRACE_OS,
+               "yaffs_removexattr of object %d", obj->obj_id);
+
+       if (error == 0) {
+               int result;
+               dev = obj->my_dev;
+               yaffs_gross_lock(dev);
+               result = yaffs_remove_xattrib(obj, name);
+               if (result == YAFFS_OK)
+                       error = 0;
+               else if (result < 0)
+                       error = result;
+               yaffs_gross_unlock(dev);
+
+       }
+       yaffs_trace(YAFFS_TRACE_OS,
+               "yaffs_removexattr done returning %d", error);
+
+       return error;
+}
+
+static ssize_t yaffs_listxattr(struct dentry * dentry, char *buff, size_t size)
+{
+       struct inode *inode = dentry->d_inode;
+       int error = 0;
+       struct yaffs_dev *dev;
+       struct yaffs_obj *obj = yaffs_inode_to_obj(inode);
+
+       yaffs_trace(YAFFS_TRACE_OS,
+               "yaffs_listxattr of object %d", obj->obj_id);
+
+       if (error == 0) {
+               dev = obj->my_dev;
+               yaffs_gross_lock(dev);
+               error = yaffs_list_xattrib(obj, buff, size);
+               yaffs_gross_unlock(dev);
+
+       }
+       yaffs_trace(YAFFS_TRACE_OS,
+               "yaffs_listxattr done returning %d", error);
+
+       return error;
+}
+
+
+static const struct inode_operations yaffs_file_inode_operations = {
+       .setattr = yaffs_setattr,
+       .setxattr = yaffs_setxattr,
+       .getxattr = yaffs_getxattr,
+       .listxattr = yaffs_listxattr,
+       .removexattr = yaffs_removexattr,
+};
+
+
+static int yaffs_readlink(struct dentry *dentry, char __user * buffer,
+                         int buflen)
+{
+       unsigned char *alias;
+       int ret;
+
+       struct yaffs_dev *dev = yaffs_dentry_to_obj(dentry)->my_dev;
+
+       yaffs_gross_lock(dev);
+
+       alias = yaffs_get_symlink_alias(yaffs_dentry_to_obj(dentry));
+
+       yaffs_gross_unlock(dev);
+
+       if (!alias)
+               return -ENOMEM;
+
+       ret = vfs_readlink(dentry, buffer, buflen, alias);
+       kfree(alias);
+       return ret;
+}
+
+#if (YAFFS_NEW_FOLLOW_LINK == 1)
+static void *yaffs_follow_link(struct dentry *dentry, struct nameidata *nd)
+{
+       void *ret;
+#else
+static int yaffs_follow_link(struct dentry *dentry, struct nameidata *nd)
+{
+       int ret
+#endif
+       unsigned char *alias;
+       int ret_int = 0;
+       struct yaffs_dev *dev = yaffs_dentry_to_obj(dentry)->my_dev;
+
+       yaffs_gross_lock(dev);
+
+       alias = yaffs_get_symlink_alias(yaffs_dentry_to_obj(dentry));
+       yaffs_gross_unlock(dev);
+
+       if (!alias) {
+               ret_int = -ENOMEM;
+               goto out;
+       }
+#if (YAFFS_NEW_FOLLOW_LINK == 1)
+       nd_set_link(nd, alias);
+       ret = alias;
+out:
+       if (ret_int)
+               ret = ERR_PTR(ret_int);
+       return ret;
+#else
+       ret = vfs_follow_link(nd, alias);
+       kfree(alias);
+out:
+       if (ret_int)
+               ret = ret_int;
+       return ret;
+#endif
+}
+
+
+#ifdef YAFFS_HAS_PUT_INODE
+
+/* For now put inode is just for debugging
+ * Put inode is called when the inode **structure** is put.
+ */
+static void yaffs_put_inode(struct inode *inode)
+{
+       yaffs_trace(YAFFS_TRACE_OS,
+               "yaffs_put_inode: ino %d, count %d"),
+               (int)inode->i_ino, atomic_read(&inode->i_count);
+
+}
+#endif
+
+#if (YAFFS_NEW_FOLLOW_LINK == 1)
+void yaffs_put_link(struct dentry *dentry, struct nameidata *nd, void *alias)
+{
+       kfree(alias);
+}
+#endif
+
+static const struct inode_operations yaffs_symlink_inode_operations = {
+       .readlink = yaffs_readlink,
+       .follow_link = yaffs_follow_link,
+#if (YAFFS_NEW_FOLLOW_LINK == 1)
+       .put_link = yaffs_put_link,
+#endif
+       .setattr = yaffs_setattr,
+       .setxattr = yaffs_setxattr,
+       .getxattr = yaffs_getxattr,
+       .listxattr = yaffs_listxattr,
+       .removexattr = yaffs_removexattr,
+};
+
+#ifdef YAFFS_USE_OWN_IGET
+
+static struct inode *yaffs_iget(struct super_block *sb, unsigned long ino)
+{
+       struct inode *inode;
+       struct yaffs_obj *obj;
+       struct yaffs_dev *dev = yaffs_super_to_dev(sb);
+
+       yaffs_trace(YAFFS_TRACE_OS, "yaffs_iget for %lu", ino);
+
+       inode = iget_locked(sb, ino);
+       if (!inode)
+               return ERR_PTR(-ENOMEM);
+       if (!(inode->i_state & I_NEW))
+               return inode;
+
+       /* NB This is called as a side effect of other functions, but
+        * we had to release the lock to prevent deadlocks, so
+        * need to lock again.
+        */
+
+       yaffs_gross_lock(dev);
+
+       obj = yaffs_find_by_number(dev, inode->i_ino);
+
+       yaffs_fill_inode_from_obj(inode, obj);
+
+       yaffs_gross_unlock(dev);
+
+       unlock_new_inode(inode);
+       return inode;
+}
+
+#else
+
+static void yaffs_read_inode(struct inode *inode)
+{
+       /* NB This is called as a side effect of other functions, but
+        * we had to release the lock to prevent deadlocks, so
+        * need to lock again.
+        */
+
+       struct yaffs_obj *obj;
+       struct yaffs_dev *dev = yaffs_super_to_dev(inode->i_sb);
+
+       yaffs_trace(YAFFS_TRACE_OS,
+               "yaffs_read_inode for %d", (int)inode->i_ino);
+
+       if (current != yaffs_dev_to_lc(dev)->readdir_process)
+               yaffs_gross_lock(dev);
+
+       obj = yaffs_find_by_number(dev, inode->i_ino);
+
+       yaffs_fill_inode_from_obj(inode, obj);
+
+       if (current != yaffs_dev_to_lc(dev)->readdir_process)
+               yaffs_gross_unlock(dev);
+}
+
+#endif
+
+
+
+struct inode *yaffs_get_inode(struct super_block *sb, int mode, int dev,
+                             struct yaffs_obj *obj)
+{
+       struct inode *inode;
+
+       if (!sb) {
+               yaffs_trace(YAFFS_TRACE_OS,
+                       "yaffs_get_inode for NULL super_block!!");
+               return NULL;
+
+       }
+
+       if (!obj) {
+               yaffs_trace(YAFFS_TRACE_OS,
+                       "yaffs_get_inode for NULL object!!");
+               return NULL;
+
+       }
+
+       yaffs_trace(YAFFS_TRACE_OS,
+               "yaffs_get_inode for object %d", obj->obj_id);
+
+       inode = Y_IGET(sb, obj->obj_id);
+       if (IS_ERR(inode))
+               return NULL;
+
+       /* NB Side effect: iget calls back to yaffs_read_inode(). */
+       /* iget also increments the inode's i_count */
+       /* NB You can't be holding gross_lock or deadlock will happen! */
+
+       return inode;
+}
+
+
+
+#if LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 29)
+#define YCRED(x) x
+#else
+#define YCRED(x) (x->cred)
+#endif
+
+#if (LINUX_VERSION_CODE >= KERNEL_VERSION(3, 4, 0))
+static int yaffs_mknod(struct inode *dir, struct dentry *dentry, umode_t mode,
+                      dev_t rdev)
+#elif (LINUX_VERSION_CODE > KERNEL_VERSION(2, 5, 0))
+static int yaffs_mknod(struct inode *dir, struct dentry *dentry, int mode,
+                      dev_t rdev)
+#else
+static int yaffs_mknod(struct inode *dir, struct dentry *dentry, int mode,
+                      int rdev)
+#endif
+{
+       struct inode *inode;
+
+       struct yaffs_obj *obj = NULL;
+       struct yaffs_dev *dev;
+
+       struct yaffs_obj *parent = yaffs_inode_to_obj(dir);
+
+       int error = -ENOSPC;
+       uid_t uid = YCRED(current)->fsuid;
+       gid_t gid =
+           (dir->i_mode & S_ISGID) ? dir->i_gid : YCRED(current)->fsgid;
+
+       if ((dir->i_mode & S_ISGID) && S_ISDIR(mode))
+               mode |= S_ISGID;
+
+       if (parent) {
+               yaffs_trace(YAFFS_TRACE_OS,
+                       "yaffs_mknod: parent object %d type %d",
+                       parent->obj_id, parent->variant_type);
+       } else {
+               yaffs_trace(YAFFS_TRACE_OS,
+                       "yaffs_mknod: could not get parent object");
+               return -EPERM;
+       }
+
+       yaffs_trace(YAFFS_TRACE_OS,
+               "yaffs_mknod: making oject for %s, mode %x dev %x",
+               dentry->d_name.name, mode, rdev);
+
+       dev = parent->my_dev;
+
+       yaffs_gross_lock(dev);
+
+       switch (mode & S_IFMT) {
+       default:
+               /* Special (socket, fifo, device...) */
+               yaffs_trace(YAFFS_TRACE_OS, "yaffs_mknod: making special");
+#if (LINUX_VERSION_CODE > KERNEL_VERSION(2, 5, 0))
+               obj =
+                   yaffs_create_special(parent, dentry->d_name.name, mode, uid,
+                                        gid, old_encode_dev(rdev));
+#else
+               obj =
+                   yaffs_create_special(parent, dentry->d_name.name, mode, uid,
+                                        gid, rdev);
+#endif
+               break;
+       case S_IFREG:           /* file          */
+               yaffs_trace(YAFFS_TRACE_OS, "yaffs_mknod: making file");
+               obj = yaffs_create_file(parent, dentry->d_name.name, mode, uid,
+                                       gid);
+               break;
+       case S_IFDIR:           /* directory */
+               yaffs_trace(YAFFS_TRACE_OS, "yaffs_mknod: making directory");
+               obj = yaffs_create_dir(parent, dentry->d_name.name, mode,
+                                      uid, gid);
+               break;
+       case S_IFLNK:           /* symlink */
+               yaffs_trace(YAFFS_TRACE_OS, "yaffs_mknod: making symlink");
+               obj = NULL;     /* Do we ever get here? */
+               break;
+       }
+
+       /* Can not call yaffs_get_inode() with gross lock held */
+       yaffs_gross_unlock(dev);
+
+       if (obj) {
+               inode = yaffs_get_inode(dir->i_sb, mode, rdev, obj);
+               d_instantiate(dentry, inode);
+               update_dir_time(dir);
+               yaffs_trace(YAFFS_TRACE_OS,
+                       "yaffs_mknod created object %d count = %d",
+                       obj->obj_id, atomic_read(&inode->i_count));
+               error = 0;
+               yaffs_fill_inode_from_obj(dir, parent);
+       } else {
+               yaffs_trace(YAFFS_TRACE_OS, "yaffs_mknod failed making object");
+               error = -ENOMEM;
+       }
+
+       return error;
+}
+
+#if (LINUX_VERSION_CODE >= KERNEL_VERSION(3, 4, 0))
+static int yaffs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)
+#else
+static int yaffs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
+#endif
+{
+       int ret_val;
+       yaffs_trace(YAFFS_TRACE_OS, "yaffs_mkdir");
+       ret_val = yaffs_mknod(dir, dentry, mode | S_IFDIR, 0);
+       return ret_val;
+}
+
+
+#if (LINUX_VERSION_CODE >= KERNEL_VERSION(3, 6, 0))
+static int yaffs_create(struct inode *dir, struct dentry *dentry, umode_t mode,
+                       bool dummy)
+#elif (LINUX_VERSION_CODE >= KERNEL_VERSION(3, 4, 0))
+static int yaffs_create(struct inode *dir, struct dentry *dentry, umode_t mode,
+                       struct nameidata *n)
+#elif (LINUX_VERSION_CODE > KERNEL_VERSION(2, 5, 0))
+static int yaffs_create(struct inode *dir, struct dentry *dentry, int mode,
+                       struct nameidata *n)
+#else
+static int yaffs_create(struct inode *dir, struct dentry *dentry, int mode)
+#endif
+{
+       yaffs_trace(YAFFS_TRACE_OS, "yaffs_create");
+       return yaffs_mknod(dir, dentry, mode | S_IFREG, 0);
+}
+
+#if (LINUX_VERSION_CODE >= KERNEL_VERSION(3, 6, 0))
+static struct dentry *yaffs_lookup(struct inode *dir, struct dentry *dentry,
+                                  unsigned int dummy)
+#elif (LINUX_VERSION_CODE > KERNEL_VERSION(2, 5, 0))
+static struct dentry *yaffs_lookup(struct inode *dir, struct dentry *dentry,
+                                  struct nameidata *n)
+#else
+static struct dentry *yaffs_lookup(struct inode *dir, struct dentry *dentry)
+#endif
+{
+       struct yaffs_obj *obj;
+       struct inode *inode = NULL;     /* NCB 2.5/2.6 needs NULL here */
+
+       struct yaffs_dev *dev = yaffs_inode_to_obj(dir)->my_dev;
+
+       if (current != yaffs_dev_to_lc(dev)->readdir_process)
+               yaffs_gross_lock(dev);
+
+       yaffs_trace(YAFFS_TRACE_OS, "yaffs_lookup for %d:%s",
+               yaffs_inode_to_obj(dir)->obj_id, dentry->d_name.name);
+
+       obj = yaffs_find_by_name(yaffs_inode_to_obj(dir), dentry->d_name.name);
+
+       obj = yaffs_get_equivalent_obj(obj);    /* in case it was a hardlink */
+
+       /* Can't hold gross lock when calling yaffs_get_inode() */
+       if (current != yaffs_dev_to_lc(dev)->readdir_process)
+               yaffs_gross_unlock(dev);
+
+       if (obj) {
+               yaffs_trace(YAFFS_TRACE_OS,
+                       "yaffs_lookup found %d", obj->obj_id);
+
+               inode = yaffs_get_inode(dir->i_sb, obj->yst_mode, 0, obj);
+       } else {
+               yaffs_trace(YAFFS_TRACE_OS, "yaffs_lookup not found");
+
+       }
+
+/* added NCB for 2.5/6 compatability - forces add even if inode is
+ * NULL which creates dentry hash */
+       d_add(dentry, inode);
+
+       return NULL;
+}
+
+/*
+ * Create a link...
+ */
+static int yaffs_link(struct dentry *old_dentry, struct inode *dir,
+                     struct dentry *dentry)
+{
+       struct inode *inode = old_dentry->d_inode;
+       struct yaffs_obj *obj = NULL;
+       struct yaffs_obj *link = NULL;
+       struct yaffs_dev *dev;
+
+       yaffs_trace(YAFFS_TRACE_OS, "yaffs_link");
+
+       obj = yaffs_inode_to_obj(inode);
+       dev = obj->my_dev;
+
+       yaffs_gross_lock(dev);
+
+       if (!S_ISDIR(inode->i_mode))    /* Don't link directories */
+               link =
+                   yaffs_link_obj(yaffs_inode_to_obj(dir), dentry->d_name.name,
+                                  obj);
+
+       if (link) {
+               set_nlink(old_dentry->d_inode, yaffs_get_obj_link_count(obj));
+               d_instantiate(dentry, old_dentry->d_inode);
+               atomic_inc(&old_dentry->d_inode->i_count);
+               yaffs_trace(YAFFS_TRACE_OS,
+                       "yaffs_link link count %d i_count %d",
+                       old_dentry->d_inode->i_nlink,
+                       atomic_read(&old_dentry->d_inode->i_count));
+       }
+
+       yaffs_gross_unlock(dev);
+
+       if (link) {
+               update_dir_time(dir);
+               return 0;
+       }
+
+       return -EPERM;
+}
+
+static int yaffs_symlink(struct inode *dir, struct dentry *dentry,
+                        const char *symname)
+{
+       struct yaffs_obj *obj;
+       struct yaffs_dev *dev;
+       uid_t uid = YCRED(current)->fsuid;
+       gid_t gid =
+           (dir->i_mode & S_ISGID) ? dir->i_gid : YCRED(current)->fsgid;
+
+       yaffs_trace(YAFFS_TRACE_OS, "yaffs_symlink");
+
+       if (strnlen(dentry->d_name.name, YAFFS_MAX_NAME_LENGTH + 1) >
+                               YAFFS_MAX_NAME_LENGTH)
+               return -ENAMETOOLONG;
+
+       if (strnlen(symname, YAFFS_MAX_ALIAS_LENGTH + 1) >
+                               YAFFS_MAX_ALIAS_LENGTH)
+               return -ENAMETOOLONG;
+
+       dev = yaffs_inode_to_obj(dir)->my_dev;
+       yaffs_gross_lock(dev);
+       obj = yaffs_create_symlink(yaffs_inode_to_obj(dir), dentry->d_name.name,
+                                  S_IFLNK | S_IRWXUGO, uid, gid, symname);
+       yaffs_gross_unlock(dev);
+
+       if (obj) {
+               struct inode *inode;
+
+               inode = yaffs_get_inode(dir->i_sb, obj->yst_mode, 0, obj);
+               d_instantiate(dentry, inode);
+               update_dir_time(dir);
+               yaffs_trace(YAFFS_TRACE_OS, "symlink created OK");
+               return 0;
+       } else {
+               yaffs_trace(YAFFS_TRACE_OS, "symlink not created");
+       }
+
+       return -ENOMEM;
+}
+
+/*
+ * The VFS layer already does all the dentry stuff for rename.
+ *
+ * NB: POSIX says you can rename an object over an old object of the same name
+ */
+static int yaffs_rename(struct inode *old_dir, struct dentry *old_dentry,
+                       struct inode *new_dir, struct dentry *new_dentry)
+{
+       struct yaffs_dev *dev;
+       int ret_val = YAFFS_FAIL;
+       struct yaffs_obj *target;
+
+       yaffs_trace(YAFFS_TRACE_OS, "yaffs_rename");
+       dev = yaffs_inode_to_obj(old_dir)->my_dev;
+
+       yaffs_gross_lock(dev);
+
+       /* Check if the target is an existing directory that is not empty. */
+       target = yaffs_find_by_name(yaffs_inode_to_obj(new_dir),
+                                   new_dentry->d_name.name);
+
+       if (target && target->variant_type == YAFFS_OBJECT_TYPE_DIRECTORY &&
+           !list_empty(&target->variant.dir_variant.children)) {
+
+               yaffs_trace(YAFFS_TRACE_OS, "target is non-empty dir");
+
+               ret_val = YAFFS_FAIL;
+       } else {
+               /* Now does unlinking internally using shadowing mechanism */
+               yaffs_trace(YAFFS_TRACE_OS, "calling yaffs_rename_obj");
+
+               ret_val = yaffs_rename_obj(yaffs_inode_to_obj(old_dir),
+                                          old_dentry->d_name.name,
+                                          yaffs_inode_to_obj(new_dir),
+                                          new_dentry->d_name.name);
+       }
+       yaffs_gross_unlock(dev);
+
+       if (ret_val == YAFFS_OK) {
+               if (target)
+                       inode_dec_link_count(new_dentry->d_inode);
+
+               update_dir_time(old_dir);
+               if (old_dir != new_dir)
+                       update_dir_time(new_dir);
+               return 0;
+       } else {
+               return -ENOTEMPTY;
+       }
+}
+
+
+
+
+static int yaffs_unlink(struct inode *dir, struct dentry *dentry)
+{
+       int ret_val;
+
+       struct yaffs_dev *dev;
+       struct yaffs_obj *obj;
+
+       yaffs_trace(YAFFS_TRACE_OS, "yaffs_unlink %d:%s",
+               (int)(dir->i_ino), dentry->d_name.name);
+       obj = yaffs_inode_to_obj(dir);
+       dev = obj->my_dev;
+
+       yaffs_gross_lock(dev);
+
+       ret_val = yaffs_unlinker(obj, dentry->d_name.name);
+
+       if (ret_val == YAFFS_OK) {
+               inode_dec_link_count(dentry->d_inode);
+               dir->i_version++;
+               yaffs_gross_unlock(dev);
+               update_dir_time(dir);
+               return 0;
+       }
+       yaffs_gross_unlock(dev);
+       return -ENOTEMPTY;
+}
+
+
+
+static const struct inode_operations yaffs_dir_inode_operations = {
+       .create = yaffs_create,
+       .lookup = yaffs_lookup,
+       .link = yaffs_link,
+       .unlink = yaffs_unlink,
+       .symlink = yaffs_symlink,
+       .mkdir = yaffs_mkdir,
+       .rmdir = yaffs_unlink,
+       .mknod = yaffs_mknod,
+       .rename = yaffs_rename,
+       .setattr = yaffs_setattr,
+       .setxattr = yaffs_setxattr,
+       .getxattr = yaffs_getxattr,
+       .listxattr = yaffs_listxattr,
+       .removexattr = yaffs_removexattr,
+};
+
+/*-----------------------------------------------------------------*/
+/* Directory search context allows us to unlock access to yaffs during
+ * filldir without causing problems with the directory being modified.
+ * This is similar to the tried and tested mechanism used in yaffs direct.
+ *
+ * A search context iterates along a doubly linked list of siblings in the
+ * directory. If the iterating object is deleted then this would corrupt
+ * the list iteration, likely causing a crash. The search context avoids
+ * this by using the remove_obj_fn to move the search context to the
+ * next object before the object is deleted.
+ *
+ * Many readdirs (and thus seach conexts) may be alive simulateously so
+ * each struct yaffs_dev has a list of these.
+ *
+ * A seach context lives for the duration of a readdir.
+ *
+ * All these functions must be called while yaffs is locked.
+ */
+
+struct yaffs_search_context {
+       struct yaffs_dev *dev;
+       struct yaffs_obj *dir_obj;
+       struct yaffs_obj *next_return;
+       struct list_head others;
+};
+
+/*
+ * yaffs_new_search() creates a new search context, initialises it and
+ * adds it to the device's search context list.
+ *
+ * Called at start of readdir.
+ */
+static struct yaffs_search_context *yaffs_new_search(struct yaffs_obj *dir)
+{
+       struct yaffs_dev *dev = dir->my_dev;
+       struct yaffs_search_context *sc =
+           kmalloc(sizeof(struct yaffs_search_context), GFP_NOFS);
+       if (sc) {
+               sc->dir_obj = dir;
+               sc->dev = dev;
+               if (list_empty(&sc->dir_obj->variant.dir_variant.children))
+                       sc->next_return = NULL;
+               else
+                       sc->next_return =
+                           list_entry(dir->variant.dir_variant.children.next,
+                                      struct yaffs_obj, siblings);
+               INIT_LIST_HEAD(&sc->others);
+               list_add(&sc->others, &(yaffs_dev_to_lc(dev)->search_contexts));
+       }
+       return sc;
+}
+
+/*
+ * yaffs_search_end() disposes of a search context and cleans up.
+ */
+static void yaffs_search_end(struct yaffs_search_context *sc)
+{
+       if (sc) {
+               list_del(&sc->others);
+               kfree(sc);
+       }
+}
+
+/*
+ * yaffs_search_advance() moves a search context to the next object.
+ * Called when the search iterates or when an object removal causes
+ * the search context to be moved to the next object.
+ */
+static void yaffs_search_advance(struct yaffs_search_context *sc)
+{
+       if (!sc)
+               return;
+
+       if (sc->next_return == NULL ||
+           list_empty(&sc->dir_obj->variant.dir_variant.children))
+               sc->next_return = NULL;
+       else {
+               struct list_head *next = sc->next_return->siblings.next;
+
+               if (next == &sc->dir_obj->variant.dir_variant.children)
+                       sc->next_return = NULL; /* end of list */
+               else
+                       sc->next_return =
+                           list_entry(next, struct yaffs_obj, siblings);
+       }
+}
+
+/*
+ * yaffs_remove_obj_callback() is called when an object is unlinked.
+ * We check open search contexts and advance any which are currently
+ * on the object being iterated.
+ */
+static void yaffs_remove_obj_callback(struct yaffs_obj *obj)
+{
+
+       struct list_head *i;
+       struct yaffs_search_context *sc;
+       struct list_head *search_contexts =
+           &(yaffs_dev_to_lc(obj->my_dev)->search_contexts);
+
+       /* Iterate through the directory search contexts.
+        * If any are currently on the object being removed, then advance
+        * the search context to the next object to prevent a hanging pointer.
+        */
+       list_for_each(i, search_contexts) {
+               sc = list_entry(i, struct yaffs_search_context, others);
+               if (sc->next_return == obj)
+                       yaffs_search_advance(sc);
+       }
+
+}
+
+
+/*-----------------------------------------------------------------*/
+
+static int yaffs_readdir(struct file *f, void *dirent, filldir_t filldir)
+{
+       struct yaffs_obj *obj;
+       struct yaffs_dev *dev;
+       struct yaffs_search_context *sc;
+       struct inode *inode = f->f_dentry->d_inode;
+       unsigned long offset, curoffs;
+       struct yaffs_obj *l;
+       int ret_val = 0;
+
+       char name[YAFFS_MAX_NAME_LENGTH + 1];
+
+       obj = yaffs_dentry_to_obj(f->f_dentry);
+       dev = obj->my_dev;
+
+       yaffs_gross_lock(dev);
+
+       yaffs_dev_to_lc(dev)->readdir_process = current;
+
+       offset = f->f_pos;
+
+       sc = yaffs_new_search(obj);
+       if (!sc) {
+               ret_val = -ENOMEM;
+               goto out;
+       }
+
+       yaffs_trace(YAFFS_TRACE_OS,
+               "yaffs_readdir: starting at %d", (int)offset);
+
+       if (offset == 0) {
+               yaffs_trace(YAFFS_TRACE_OS,
+                       "yaffs_readdir: entry . ino %d",
+                       (int)inode->i_ino);
+               yaffs_gross_unlock(dev);
+               if (filldir(dirent, ".", 1, offset, inode->i_ino, DT_DIR) < 0) {
+                       yaffs_gross_lock(dev);
+                       goto out;
+               }
+               yaffs_gross_lock(dev);
+               offset++;
+               f->f_pos++;
+       }
+       if (offset == 1) {
+               yaffs_trace(YAFFS_TRACE_OS,
+                       "yaffs_readdir: entry .. ino %d",
+                       (int)f->f_dentry->d_parent->d_inode->i_ino);
+               yaffs_gross_unlock(dev);
+               if (filldir(dirent, "..", 2, offset,
+                           f->f_dentry->d_parent->d_inode->i_ino,
+                           DT_DIR) < 0) {
+                       yaffs_gross_lock(dev);
+                       goto out;
+               }
+               yaffs_gross_lock(dev);
+               offset++;
+               f->f_pos++;
+       }
+
+       curoffs = 1;
+
+       /* If the directory has changed since the open or last call to
+          readdir, rewind to after the 2 canned entries. */
+       if (f->f_version != inode->i_version) {
+               offset = 2;
+               f->f_pos = offset;
+               f->f_version = inode->i_version;
+       }
+
+       while (sc->next_return) {
+               curoffs++;
+               l = sc->next_return;
+               if (curoffs >= offset) {
+                       int this_inode = yaffs_get_obj_inode(l);
+                       int this_type = yaffs_get_obj_type(l);
+
+                       yaffs_get_obj_name(l, name, YAFFS_MAX_NAME_LENGTH + 1);
+                       yaffs_trace(YAFFS_TRACE_OS,
+                               "yaffs_readdir: %s inode %d",
+                               name, yaffs_get_obj_inode(l));
+
+                       yaffs_gross_unlock(dev);
+
+                       if (filldir(dirent,
+                                   name,
+                                   strlen(name),
+                                   offset, this_inode, this_type) < 0) {
+                               yaffs_gross_lock(dev);
+                               goto out;
+                       }
+
+                       yaffs_gross_lock(dev);
+
+                       offset++;
+                       f->f_pos++;
+               }
+               yaffs_search_advance(sc);
+       }
+
+out:
+       yaffs_search_end(sc);
+       yaffs_dev_to_lc(dev)->readdir_process = NULL;
+       yaffs_gross_unlock(dev);
+
+       return ret_val;
+}
+
+static const struct file_operations yaffs_dir_operations = {
+       .read = generic_read_dir,
+       .readdir = yaffs_readdir,
+       .fsync = yaffs_sync_object,
+       .llseek = generic_file_llseek,
+};
+
+static void yaffs_fill_inode_from_obj(struct inode *inode,
+                                     struct yaffs_obj *obj)
+{
+       if (inode && obj) {
+
+               /* Check mode against the variant type and attempt to repair if broken. */
+               u32 mode = obj->yst_mode;
+               switch (obj->variant_type) {
+               case YAFFS_OBJECT_TYPE_FILE:
+                       if (!S_ISREG(mode)) {
+                               obj->yst_mode &= ~S_IFMT;
+                               obj->yst_mode |= S_IFREG;
+                       }
+
+                       break;
+               case YAFFS_OBJECT_TYPE_SYMLINK:
+                       if (!S_ISLNK(mode)) {
+                               obj->yst_mode &= ~S_IFMT;
+                               obj->yst_mode |= S_IFLNK;
+                       }
+
+                       break;
+               case YAFFS_OBJECT_TYPE_DIRECTORY:
+                       if (!S_ISDIR(mode)) {
+                               obj->yst_mode &= ~S_IFMT;
+                               obj->yst_mode |= S_IFDIR;
+                       }
+
+                       break;
+               case YAFFS_OBJECT_TYPE_UNKNOWN:
+               case YAFFS_OBJECT_TYPE_HARDLINK:
+               case YAFFS_OBJECT_TYPE_SPECIAL:
+               default:
+                       /* TODO? */
+                       break;
+               }
+
+               inode->i_flags |= S_NOATIME;
+
+               inode->i_ino = obj->obj_id;
+               inode->i_mode = obj->yst_mode;
+               inode->i_uid = obj->yst_uid;
+               inode->i_gid = obj->yst_gid;
+#if (LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 19))
+               inode->i_blksize = inode->i_sb->s_blocksize;
+#endif
+#if (LINUX_VERSION_CODE > KERNEL_VERSION(2, 5, 0))
+
+               inode->i_rdev = old_decode_dev(obj->yst_rdev);
+               inode->i_atime.tv_sec = (time_t) (obj->yst_atime);
+               inode->i_atime.tv_nsec = 0;
+               inode->i_mtime.tv_sec = (time_t) obj->yst_mtime;
+               inode->i_mtime.tv_nsec = 0;
+               inode->i_ctime.tv_sec = (time_t) obj->yst_ctime;
+               inode->i_ctime.tv_nsec = 0;
+#else
+               inode->i_rdev = obj->yst_rdev;
+               inode->i_atime = obj->yst_atime;
+               inode->i_mtime = obj->yst_mtime;
+               inode->i_ctime = obj->yst_ctime;
+#endif
+               inode->i_size = yaffs_get_obj_length(obj);
+               inode->i_blocks = (inode->i_size + 511) >> 9;
+
+               set_nlink(inode, yaffs_get_obj_link_count(obj));
+
+               yaffs_trace(YAFFS_TRACE_OS,
+                       "yaffs_fill_inode mode %x uid %d gid %d size %lld count %d",
+                       inode->i_mode, inode->i_uid, inode->i_gid,
+                       inode->i_size, atomic_read(&inode->i_count));
+
+               switch (obj->yst_mode & S_IFMT) {
+               default:        /* fifo, device or socket */
+#if (LINUX_VERSION_CODE > KERNEL_VERSION(2, 5, 0))
+                       init_special_inode(inode, obj->yst_mode,
+                                          old_decode_dev(obj->yst_rdev));
+#else
+                       init_special_inode(inode, obj->yst_mode,
+                                          (dev_t) (obj->yst_rdev));
+#endif
+                       break;
+               case S_IFREG:   /* file */
+                       inode->i_op = &yaffs_file_inode_operations;
+                       inode->i_fop = &yaffs_file_operations;
+                       inode->i_mapping->a_ops =
+                           &yaffs_file_address_operations;
+                       break;
+               case S_IFDIR:   /* directory */
+                       inode->i_op = &yaffs_dir_inode_operations;
+                       inode->i_fop = &yaffs_dir_operations;
+                       break;
+               case S_IFLNK:   /* symlink */
+                       inode->i_op = &yaffs_symlink_inode_operations;
+                       break;
+               }
+
+               yaffs_inode_to_obj_lv(inode) = obj;
+
+               obj->my_inode = inode;
+
+       } else {
+               yaffs_trace(YAFFS_TRACE_OS,
+                       "yaffs_fill_inode invalid parameters");
+       }
+
+}
+
+
+
+/*
+ * yaffs background thread functions .
+ * yaffs_bg_thread_fn() the thread function
+ * yaffs_bg_start() launches the background thread.
+ * yaffs_bg_stop() cleans up the background thread.
+ *
+ * NB:
+ * The thread should only run after the yaffs is initialised
+ * The thread should be stopped before yaffs is unmounted.
+ * The thread should not do any writing while the fs is in read only.
+ */
+
+static unsigned yaffs_bg_gc_urgency(struct yaffs_dev *dev)
+{
+       unsigned erased_chunks =
+           dev->n_erased_blocks * dev->param.chunks_per_block;
+       struct yaffs_linux_context *context = yaffs_dev_to_lc(dev);
+       unsigned scattered = 0; /* Free chunks not in an erased block */
+
+       if (erased_chunks < dev->n_free_chunks)
+               scattered = (dev->n_free_chunks - erased_chunks);
+
+       if (!context->bg_running)
+               return 0;
+       else if (scattered < (dev->param.chunks_per_block * 2))
+               return 0;
+       else if (erased_chunks > dev->n_free_chunks / 2)
+               return 0;
+       else if (erased_chunks > dev->n_free_chunks / 4)
+               return 1;
+       else
+               return 2;
+}
+
+#ifdef YAFFS_COMPILE_BACKGROUND
+
+void yaffs_background_waker(unsigned long data)
+{
+       wake_up_process((struct task_struct *)data);
+}
+
+static int yaffs_bg_thread_fn(void *data)
+{
+       struct yaffs_dev *dev = (struct yaffs_dev *)data;
+       struct yaffs_linux_context *context = yaffs_dev_to_lc(dev);
+       unsigned long now = jiffies;
+       unsigned long next_dir_update = now;
+       unsigned long next_gc = now;
+       unsigned long expires;
+       unsigned int urgency;
+
+       int gc_result;
+       struct timer_list timer;
+
+       yaffs_trace(YAFFS_TRACE_BACKGROUND,
+               "yaffs_background starting for dev %p", (void *)dev);
+
+#ifdef YAFFS_COMPILE_FREEZER
+       set_freezable();
+#endif
+       while (context->bg_running) {
+               yaffs_trace(YAFFS_TRACE_BACKGROUND, "yaffs_background");
+
+               if (kthread_should_stop())
+                       break;
+
+#ifdef YAFFS_COMPILE_FREEZER
+               if (try_to_freeze())
+                       continue;
+#endif
+               yaffs_gross_lock(dev);
+
+               now = jiffies;
+
+               if (time_after(now, next_dir_update) && yaffs_bg_enable) {
+                       yaffs_update_dirty_dirs(dev);
+                       next_dir_update = now + HZ;
+               }
+
+               if (time_after(now, next_gc) && yaffs_bg_enable) {
+                       if (!dev->is_checkpointed) {
+                               urgency = yaffs_bg_gc_urgency(dev);
+                               gc_result = yaffs_bg_gc(dev, urgency);
+                               if (urgency > 1)
+                                       next_gc = now + HZ / 20 + 1;
+                               else if (urgency > 0)
+                                       next_gc = now + HZ / 10 + 1;
+                               else
+                                       next_gc = now + HZ * 2;
+                       } else  {
+                               /*
+                                * gc not running so set to next_dir_update
+                                * to cut down on wake ups
+                                */
+                               next_gc = next_dir_update;
+                        }
+               }
+               yaffs_gross_unlock(dev);
+#if 1
+               expires = next_dir_update;
+               if (time_before(next_gc, expires))
+                       expires = next_gc;
+               if (time_before(expires, now))
+                       expires = now + HZ;
+
+               Y_INIT_TIMER(&timer);
+               timer.expires = expires + 1;
+               timer.data = (unsigned long)current;
+               timer.function = yaffs_background_waker;
+
+               set_current_state(TASK_INTERRUPTIBLE);
+               add_timer(&timer);
+               schedule();
+               del_timer_sync(&timer);
+#else
+               msleep(10);
+#endif
+       }
+
+       return 0;
+}
+
+static int yaffs_bg_start(struct yaffs_dev *dev)
+{
+       int retval = 0;
+       struct yaffs_linux_context *context = yaffs_dev_to_lc(dev);
+
+       if (dev->read_only)
+               return -1;
+
+       context->bg_running = 1;
+
+       context->bg_thread = kthread_run(yaffs_bg_thread_fn,
+                                        (void *)dev, "yaffs-bg-%d",
+                                        context->mount_id);
+
+       if (IS_ERR(context->bg_thread)) {
+               retval = PTR_ERR(context->bg_thread);
+               context->bg_thread = NULL;
+               context->bg_running = 0;
+       }
+       return retval;
+}
+
+static void yaffs_bg_stop(struct yaffs_dev *dev)
+{
+       struct yaffs_linux_context *ctxt = yaffs_dev_to_lc(dev);
+
+       ctxt->bg_running = 0;
+
+       if (ctxt->bg_thread) {
+               kthread_stop(ctxt->bg_thread);
+               ctxt->bg_thread = NULL;
+       }
+}
+#else
+static int yaffs_bg_thread_fn(void *data)
+{
+       return 0;
+}
+
+static int yaffs_bg_start(struct yaffs_dev *dev)
+{
+       return 0;
+}
+
+static void yaffs_bg_stop(struct yaffs_dev *dev)
+{
+}
+#endif
+
+
+static void yaffs_flush_inodes(struct super_block *sb)
+{
+       struct inode *iptr;
+       struct yaffs_obj *obj;
+
+       list_for_each_entry(iptr, &sb->s_inodes, i_sb_list) {
+               obj = yaffs_inode_to_obj(iptr);
+               if (obj) {
+                       yaffs_trace(YAFFS_TRACE_OS,
+                               "flushing obj %d",
+                               obj->obj_id);
+                       yaffs_flush_file(obj, 1, 0);
+               }
+       }
+}
+
+static void yaffs_flush_super(struct super_block *sb, int do_checkpoint)
+{
+       struct yaffs_dev *dev = yaffs_super_to_dev(sb);
+       if (!dev)
+               return;
+
+       yaffs_flush_inodes(sb);
+       yaffs_update_dirty_dirs(dev);
+       yaffs_flush_whole_cache(dev);
+       if (do_checkpoint)
+               yaffs_checkpoint_save(dev);
+}
+
+static LIST_HEAD(yaffs_context_list);
+struct mutex yaffs_context_lock;
+
+static void yaffs_put_super(struct super_block *sb)
+{
+       struct yaffs_dev *dev = yaffs_super_to_dev(sb);
+       struct mtd_info *mtd = yaffs_dev_to_mtd(dev);
+
+       yaffs_trace(YAFFS_TRACE_OS | YAFFS_TRACE_ALWAYS,
+                       "yaffs_put_super");
+
+       yaffs_trace(YAFFS_TRACE_OS | YAFFS_TRACE_BACKGROUND,
+               "Shutting down yaffs background thread");
+       yaffs_bg_stop(dev);
+       yaffs_trace(YAFFS_TRACE_OS | YAFFS_TRACE_BACKGROUND,
+               "yaffs background thread shut down");
+
+       yaffs_gross_lock(dev);
+
+       yaffs_flush_super(sb, 1);
+
+       yaffs_deinitialise(dev);
+
+       yaffs_gross_unlock(dev);
+
+       mutex_lock(&yaffs_context_lock);
+       list_del_init(&(yaffs_dev_to_lc(dev)->context_list));
+       mutex_unlock(&yaffs_context_lock);
+
+       if (yaffs_dev_to_lc(dev)->spare_buffer) {
+               kfree(yaffs_dev_to_lc(dev)->spare_buffer);
+               yaffs_dev_to_lc(dev)->spare_buffer = NULL;
+       }
+
+       kfree(dev);
+
+       yaffs_put_mtd_device(mtd);
+
+       yaffs_trace(YAFFS_TRACE_OS | YAFFS_TRACE_ALWAYS,
+                       "yaffs_put_super done");
+}
+
+
+static unsigned yaffs_gc_control_callback(struct yaffs_dev *dev)
+{
+       return yaffs_gc_control;
+}
+
+
+#ifdef YAFFS_COMPILE_EXPORTFS
+
+static struct inode *yaffs2_nfs_get_inode(struct super_block *sb, uint64_t ino,
+                                         uint32_t generation)
+{
+       return Y_IGET(sb, ino);
+}
+
+static struct dentry *yaffs2_fh_to_dentry(struct super_block *sb,
+                                         struct fid *fid, int fh_len,
+                                         int fh_type)
+{
+       return generic_fh_to_dentry(sb, fid, fh_len, fh_type,
+                                   yaffs2_nfs_get_inode);
+}
+
+static struct dentry *yaffs2_fh_to_parent(struct super_block *sb,
+                                         struct fid *fid, int fh_len,
+                                         int fh_type)
+{
+       return generic_fh_to_parent(sb, fid, fh_len, fh_type,
+                                   yaffs2_nfs_get_inode);
+}
+
+struct dentry *yaffs2_get_parent(struct dentry *dentry)
+{
+
+       struct super_block *sb = dentry->d_inode->i_sb;
+       struct dentry *parent = ERR_PTR(-ENOENT);
+       struct inode *inode;
+       unsigned long parent_ino;
+       struct yaffs_obj *d_obj;
+       struct yaffs_obj *parent_obj;
+
+       d_obj = yaffs_inode_to_obj(dentry->d_inode);
+
+       if (d_obj) {
+               parent_obj = d_obj->parent;
+               if (parent_obj) {
+                       parent_ino = yaffs_get_obj_inode(parent_obj);
+                       inode = Y_IGET(sb, parent_ino);
+
+                       if (IS_ERR(inode)) {
+                               parent = ERR_CAST(inode);
+                       } else {
+                               parent = d_obtain_alias(inode);
+                               if (!IS_ERR(parent)) {
+                                       parent = ERR_PTR(-ENOMEM);
+                                       iput(inode);
+                               }
+                       }
+               }
+       }
+
+       return parent;
+}
+
+/* Just declare a zero structure as a NULL value implies
+ * using the default functions of exportfs.
+ */
+
+static struct export_operations yaffs_export_ops = {
+       .fh_to_dentry = yaffs2_fh_to_dentry,
+       .fh_to_parent = yaffs2_fh_to_parent,
+       .get_parent = yaffs2_get_parent,
+};
+
+#endif
+
+static void yaffs_unstitch_obj(struct inode *inode, struct yaffs_obj *obj)
+{
+       /* Clear the association between the inode and
+        * the struct yaffs_obj.
+        */
+       obj->my_inode = NULL;
+       yaffs_inode_to_obj_lv(inode) = NULL;
+
+       /* If the object freeing was deferred, then the real
+        * free happens now.
+        * This should fix the inode inconsistency problem.
+        */
+       yaffs_handle_defered_free(obj);
+}
+
+#ifdef YAFFS_HAS_EVICT_INODE
+/* yaffs_evict_inode combines into one operation what was previously done in
+ * yaffs_clear_inode() and yaffs_delete_inode()
+ *
+ */
+static void yaffs_evict_inode(struct inode *inode)
+{
+       struct yaffs_obj *obj;
+       struct yaffs_dev *dev;
+       int deleteme = 0;
+
+       obj = yaffs_inode_to_obj(inode);
+
+       yaffs_trace(YAFFS_TRACE_OS,
+               "yaffs_evict_inode: ino %d, count %d %s",
+               (int)inode->i_ino, atomic_read(&inode->i_count),
+               obj ? "object exists" : "null object");
+
+       if (!inode->i_nlink && !is_bad_inode(inode))
+               deleteme = 1;
+       truncate_inode_pages(&inode->i_data, 0);
+       Y_CLEAR_INODE(inode);
+
+       if (deleteme && obj) {
+               dev = obj->my_dev;
+               yaffs_gross_lock(dev);
+               yaffs_del_obj(obj);
+               yaffs_gross_unlock(dev);
+       }
+       if (obj) {
+               dev = obj->my_dev;
+               yaffs_gross_lock(dev);
+               yaffs_unstitch_obj(inode, obj);
+               yaffs_gross_unlock(dev);
+       }
+}
+#else
+
+/* clear is called to tell the fs to release any per-inode data it holds.
+ * The object might still exist on disk and is just being thrown out of the cache
+ * or else the object has actually been deleted and we're being called via
+ * the chain
+ *   yaffs_delete_inode() -> clear_inode()->yaffs_clear_inode()
+ */
+
+static void yaffs_clear_inode(struct inode *inode)
+{
+       struct yaffs_obj *obj;
+       struct yaffs_dev *dev;
+
+       obj = yaffs_inode_to_obj(inode);
+
+       yaffs_trace(YAFFS_TRACE_OS,
+               "yaffs_clear_inode: ino %d, count %d %s",
+               (int)inode->i_ino, atomic_read(&inode->i_count),
+               obj ? "object exists" : "null object");
+
+       if (obj) {
+               dev = obj->my_dev;
+               yaffs_gross_lock(dev);
+               yaffs_unstitch_obj(inode, obj);
+               yaffs_gross_unlock(dev);
+       }
+
+}
+
+/* delete is called when the link count is zero and the inode
+ * is put (ie. nobody wants to know about it anymore, time to
+ * delete the file).
+ * NB Must call clear_inode()
+ */
+static void yaffs_delete_inode(struct inode *inode)
+{
+       struct yaffs_obj *obj = yaffs_inode_to_obj(inode);
+       struct yaffs_dev *dev;
+
+       yaffs_trace(YAFFS_TRACE_OS,
+               "yaffs_delete_inode: ino %d, count %d %s",
+               (int)inode->i_ino, atomic_read(&inode->i_count),
+               obj ? "object exists" : "null object");
+
+       if (obj) {
+               dev = obj->my_dev;
+               yaffs_gross_lock(dev);
+               yaffs_del_obj(obj);
+               yaffs_gross_unlock(dev);
+       }
+#if (LINUX_VERSION_CODE > KERNEL_VERSION(2, 6, 13))
+       truncate_inode_pages(&inode->i_data, 0);
+#endif
+       clear_inode(inode);
+}
+#endif
+
+
+
+
+#if (LINUX_VERSION_CODE > KERNEL_VERSION(2, 6, 17))
+static int yaffs_statfs(struct dentry *dentry, struct kstatfs *buf)
+{
+       struct yaffs_dev *dev = yaffs_dentry_to_obj(dentry)->my_dev;
+       struct super_block *sb = dentry->d_sb;
+#elif (LINUX_VERSION_CODE > KERNEL_VERSION(2, 5, 0))
+static int yaffs_statfs(struct super_block *sb, struct kstatfs *buf)
+{
+       struct yaffs_dev *dev = yaffs_super_to_dev(sb);
+#else
+static int yaffs_statfs(struct super_block *sb, struct statfs *buf)
+{
+       struct yaffs_dev *dev = yaffs_super_to_dev(sb);
+#endif
+
+       yaffs_trace(YAFFS_TRACE_OS, "yaffs_statfs");
+
+       yaffs_gross_lock(dev);
+
+       buf->f_type = YAFFS_MAGIC;
+       buf->f_bsize = sb->s_blocksize;
+       buf->f_namelen = 255;
+
+       if (dev->data_bytes_per_chunk & (dev->data_bytes_per_chunk - 1)) {
+               /* Do this if chunk size is not a power of 2 */
+
+               uint64_t bytes_in_dev;
+               uint64_t bytes_free;
+
+               bytes_in_dev =
+                   ((uint64_t)
+                    ((dev->param.end_block - dev->param.start_block +
+                      1))) * ((uint64_t) (dev->param.chunks_per_block *
+                                          dev->data_bytes_per_chunk));
+
+               do_div(bytes_in_dev, sb->s_blocksize);  /* bytes_in_dev becomes the number of blocks */
+               buf->f_blocks = bytes_in_dev;
+
+               bytes_free = ((uint64_t) (yaffs_get_n_free_chunks(dev))) *
+                   ((uint64_t) (dev->data_bytes_per_chunk));
+
+               do_div(bytes_free, sb->s_blocksize);
+
+               buf->f_bfree = bytes_free;
+
+       } else if (sb->s_blocksize > dev->data_bytes_per_chunk) {
+
+               buf->f_blocks =
+                   (dev->param.end_block - dev->param.start_block + 1) *
+                   dev->param.chunks_per_block /
+                   (sb->s_blocksize / dev->data_bytes_per_chunk);
+               buf->f_bfree =
+                   yaffs_get_n_free_chunks(dev) /
+                   (sb->s_blocksize / dev->data_bytes_per_chunk);
+       } else {
+               buf->f_blocks =
+                   (dev->param.end_block - dev->param.start_block + 1) *
+                   dev->param.chunks_per_block *
+                   (dev->data_bytes_per_chunk / sb->s_blocksize);
+
+               buf->f_bfree =
+                   yaffs_get_n_free_chunks(dev) *
+                   (dev->data_bytes_per_chunk / sb->s_blocksize);
+       }
+
+       buf->f_files = 0;
+       buf->f_ffree = 0;
+       buf->f_bavail = buf->f_bfree;
+
+       yaffs_gross_unlock(dev);
+       return 0;
+}
+
+
+
+static int yaffs_do_sync_fs(struct super_block *sb, int request_checkpoint)
+{
+
+       struct yaffs_dev *dev = yaffs_super_to_dev(sb);
+       unsigned int oneshot_checkpoint = (yaffs_auto_checkpoint & 4);
+       unsigned gc_urgent = yaffs_bg_gc_urgency(dev);
+       int do_checkpoint;
+       int dirty = yaffs_check_super_dirty(dev);
+
+       yaffs_trace(YAFFS_TRACE_OS | YAFFS_TRACE_SYNC | YAFFS_TRACE_BACKGROUND,
+               "yaffs_do_sync_fs: gc-urgency %d %s %s%s",
+               gc_urgent,
+               dirty ? "dirty" : "clean",
+               request_checkpoint ? "checkpoint requested" : "no checkpoint",
+               oneshot_checkpoint ? " one-shot" : "");
+
+       yaffs_gross_lock(dev);
+       do_checkpoint = ((request_checkpoint && !gc_urgent) ||
+                        oneshot_checkpoint) && !dev->is_checkpointed;
+
+       if (dirty || do_checkpoint) {
+               yaffs_flush_super(sb, !dev->is_checkpointed && do_checkpoint);
+               yaffs_clear_super_dirty(dev);
+               if (oneshot_checkpoint)
+                       yaffs_auto_checkpoint &= ~4;
+       }
+       yaffs_gross_unlock(dev);
+
+       return 0;
+}
+
+
+#ifdef YAFFS_HAS_WRITE_SUPER
+#if (LINUX_VERSION_CODE > KERNEL_VERSION(2, 6, 17))
+static void yaffs_write_super(struct super_block *sb)
+#else
+static int yaffs_write_super(struct super_block *sb)
+#endif
+{
+       unsigned request_checkpoint = (yaffs_auto_checkpoint >= 2);
+
+       yaffs_trace(YAFFS_TRACE_OS | YAFFS_TRACE_SYNC | YAFFS_TRACE_BACKGROUND,
+               "yaffs_write_super %s",
+               request_checkpoint ? " checkpt" : "");
+
+       yaffs_do_sync_fs(sb, request_checkpoint);
+
+#if (LINUX_VERSION_CODE < KERNEL_VERSION(2, 6, 18))
+       return 0;
+#endif
+}
+#endif
+
+#if (LINUX_VERSION_CODE > KERNEL_VERSION(2, 6, 17))
+static int yaffs_sync_fs(struct super_block *sb, int wait)
+#else
+static int yaffs_sync_fs(struct super_block *sb)
+#endif
+{
+       unsigned request_checkpoint = (yaffs_auto_checkpoint >= 1);
+
+       yaffs_trace(YAFFS_TRACE_OS | YAFFS_TRACE_SYNC,
+               "yaffs_sync_fs%s", request_checkpoint ? " checkpt" : "");
+
+       yaffs_do_sync_fs(sb, request_checkpoint);
+
+       return 0;
+}
+
+
+
+static const struct super_operations yaffs_super_ops = {
+       .statfs = yaffs_statfs,
+
+#ifndef YAFFS_USE_OWN_IGET
+       .read_inode = yaffs_read_inode,
+#endif
+#ifdef YAFFS_HAS_PUT_INODE
+       .put_inode = yaffs_put_inode,
+#endif
+       .put_super = yaffs_put_super,
+#ifdef YAFFS_HAS_EVICT_INODE
+       .evict_inode = yaffs_evict_inode,
+#else
+       .delete_inode = yaffs_delete_inode,
+       .clear_inode = yaffs_clear_inode,
+#endif
+       .sync_fs = yaffs_sync_fs,
+#ifdef YAFFS_HAS_WRITE_SUPER
+       .write_super = yaffs_write_super,
+#endif
+};
+
+struct yaffs_options {
+       int inband_tags;
+       int skip_checkpoint_read;
+       int skip_checkpoint_write;
+       int no_cache;
+       int tags_ecc_on;
+       int tags_ecc_overridden;
+       int lazy_loading_enabled;
+       int lazy_loading_overridden;
+       int empty_lost_and_found;
+       int empty_lost_and_found_overridden;
+       int disable_summary;
+};
+
+#define MAX_OPT_LEN 30
+static int yaffs_parse_options(struct yaffs_options *options,
+                              const char *options_str)
+{
+       char cur_opt[MAX_OPT_LEN + 1];
+       int p;
+       int error = 0;
+
+       /* Parse through the options which is a comma seperated list */
+
+       while (options_str && *options_str && !error) {
+               memset(cur_opt, 0, MAX_OPT_LEN + 1);
+               p = 0;
+
+               while (*options_str == ',')
+                       options_str++;
+
+               while (*options_str && *options_str != ',') {
+                       if (p < MAX_OPT_LEN) {
+                               cur_opt[p] = *options_str;
+                               p++;
+                       }
+                       options_str++;
+               }
+
+               if (!strcmp(cur_opt, "inband-tags")) {
+                       options->inband_tags = 1;
+               } else if (!strcmp(cur_opt, "tags-ecc-off")) {
+                       options->tags_ecc_on = 0;
+                       options->tags_ecc_overridden = 1;
+               } else if (!strcmp(cur_opt, "tags-ecc-on")) {
+                       options->tags_ecc_on = 1;
+                       options->tags_ecc_overridden = 1;
+               } else if (!strcmp(cur_opt, "lazy-loading-off")) {
+                       options->lazy_loading_enabled = 0;
+                       options->lazy_loading_overridden = 1;
+               } else if (!strcmp(cur_opt, "lazy-loading-on")) {
+                       options->lazy_loading_enabled = 1;
+                       options->lazy_loading_overridden = 1;
+               } else if (!strcmp(cur_opt, "disable-summary")) {
+                       options->disable_summary = 1;
+               } else if (!strcmp(cur_opt, "empty-lost-and-found-off")) {
+                       options->empty_lost_and_found = 0;
+                       options->empty_lost_and_found_overridden = 1;
+               } else if (!strcmp(cur_opt, "empty-lost-and-found-on")) {
+                       options->empty_lost_and_found = 1;
+                       options->empty_lost_and_found_overridden = 1;
+               } else if (!strcmp(cur_opt, "no-cache")) {
+                       options->no_cache = 1;
+               } else if (!strcmp(cur_opt, "no-checkpoint-read")) {
+                       options->skip_checkpoint_read = 1;
+               } else if (!strcmp(cur_opt, "no-checkpoint-write")) {
+                       options->skip_checkpoint_write = 1;
+               } else if (!strcmp(cur_opt, "no-checkpoint")) {
+                       options->skip_checkpoint_read = 1;
+                       options->skip_checkpoint_write = 1;
+               } else {
+                       printk(KERN_INFO "yaffs: Bad mount option \"%s\"\n",
+                              cur_opt);
+                       error = 1;
+               }
+       }
+
+       return error;
+}
+
+
+static struct dentry *yaffs_make_root(struct inode *inode)
+{
+#if (LINUX_VERSION_CODE < KERNEL_VERSION(3, 4, 0))
+       struct dentry *root = d_alloc_root(inode);
+
+       if (!root)
+               iput(inode);
+
+        return root;
+#else
+        return d_make_root(inode);
+#endif
+}
+
+
+
+
+static struct super_block *yaffs_internal_read_super(int yaffs_version,
+                                                    struct super_block *sb,
+                                                    void *data, int silent)
+{
+       int n_blocks;
+       struct inode *inode = NULL;
+       struct dentry *root;
+       struct yaffs_dev *dev = 0;
+       char devname_buf[BDEVNAME_SIZE + 1];
+       struct mtd_info *mtd;
+       int err;
+       char *data_str = (char *)data;
+       struct yaffs_linux_context *context = NULL;
+       struct yaffs_param *param;
+
+       int read_only = 0;
+       int inband_tags = 0;
+
+       struct yaffs_options options;
+
+       unsigned mount_id;
+       int found;
+       struct yaffs_linux_context *context_iterator;
+       struct list_head *l;
+
+       if (!sb) {
+               printk(KERN_INFO "yaffs: sb is NULL\n");
+               return NULL;
+        }
+
+       sb->s_magic = YAFFS_MAGIC;
+       sb->s_op = &yaffs_super_ops;
+       sb->s_flags |= MS_NOATIME;
+
+       read_only = ((sb->s_flags & MS_RDONLY) != 0);
+
+#ifdef YAFFS_COMPILE_EXPORTFS
+       sb->s_export_op = &yaffs_export_ops;
+#endif
+
+       if (!sb->s_dev)
+               printk(KERN_INFO "yaffs: sb->s_dev is NULL\n");
+       else if (!yaffs_devname(sb, devname_buf))
+               printk(KERN_INFO "yaffs: devname is NULL\n");
+       else
+               printk(KERN_INFO "yaffs: dev is %d name is \"%s\" %s\n",
+                      sb->s_dev,
+                      yaffs_devname(sb, devname_buf), read_only ? "ro" : "rw");
+
+       if (!data_str)
+               data_str = "";
+
+       printk(KERN_INFO "yaffs: passed flags \"%s\"\n", data_str);
+
+       memset(&options, 0, sizeof(options));
+
+       if (yaffs_parse_options(&options, data_str)) {
+               /* Option parsing failed */
+               return NULL;
+       }
+
+       sb->s_blocksize = PAGE_CACHE_SIZE;
+       sb->s_blocksize_bits = PAGE_CACHE_SHIFT;
+
+       yaffs_trace(YAFFS_TRACE_OS,
+               "yaffs_read_super: Using yaffs%d", yaffs_version);
+       yaffs_trace(YAFFS_TRACE_OS,
+               "yaffs_read_super: block size %d", (int)(sb->s_blocksize));
+
+       yaffs_trace(YAFFS_TRACE_ALWAYS,
+               "yaffs: Attempting MTD mount of %u.%u,\"%s\"",
+               MAJOR(sb->s_dev), MINOR(sb->s_dev),
+               yaffs_devname(sb, devname_buf));
+
+       /* Get the device */
+       mtd = get_mtd_device(NULL, MINOR(sb->s_dev));
+       if (!mtd) {
+               yaffs_trace(YAFFS_TRACE_ALWAYS,
+                       "yaffs: MTD device %u either not valid or unavailable",
+                       MINOR(sb->s_dev));
+               return NULL;
+       }
+
+       if (yaffs_auto_select && yaffs_version == 1 && WRITE_SIZE(mtd) >= 2048) {
+               yaffs_trace(YAFFS_TRACE_ALWAYS, "auto selecting yaffs2");
+               yaffs_version = 2;
+       }
+
+       /* Added NCB 26/5/2006 for completeness */
+       if (yaffs_version == 2 && !options.inband_tags
+           && WRITE_SIZE(mtd) == 512) {
+               yaffs_trace(YAFFS_TRACE_ALWAYS, "auto selecting yaffs1");
+               yaffs_version = 1;
+       }
+
+       if (mtd->oobavail < sizeof(struct yaffs_packed_tags2) ||
+           options.inband_tags)
+               inband_tags = 1;
+
+       if(yaffs_verify_mtd(mtd, yaffs_version, inband_tags) < 0)
+               return NULL;
+
+       /* OK, so if we got here, we have an MTD that's NAND and looks
+        * like it has the right capabilities
+        * Set the struct yaffs_dev up for mtd
+        */
+
+       if (!read_only && !(mtd->flags & MTD_WRITEABLE)) {
+               read_only = 1;
+               printk(KERN_INFO
+                      "yaffs: mtd is read only, setting superblock read only\n"
+               );
+               sb->s_flags |= MS_RDONLY;
+       }
+
+       dev = kmalloc(sizeof(struct yaffs_dev), GFP_KERNEL);
+       context = kmalloc(sizeof(struct yaffs_linux_context), GFP_KERNEL);
+
+       if (!dev || !context) {
+               if (dev)
+                       kfree(dev);
+               if (context)
+                       kfree(context);
+               dev = NULL;
+               context = NULL;
+       }
+
+       if (!dev) {
+               /* Deep shit could not allocate device structure */
+               yaffs_trace(YAFFS_TRACE_ALWAYS,
+                       "yaffs_read_super: Failed trying to allocate struct yaffs_dev."
+               );
+               return NULL;
+       }
+       memset(dev, 0, sizeof(struct yaffs_dev));
+       param = &(dev->param);
+
+       memset(context, 0, sizeof(struct yaffs_linux_context));
+       dev->os_context = context;
+       INIT_LIST_HEAD(&(context->context_list));
+       context->dev = dev;
+       context->super = sb;
+
+       dev->read_only = read_only;
+
+#if (LINUX_VERSION_CODE > KERNEL_VERSION(2, 5, 0))
+       sb->s_fs_info = dev;
+#else
+       sb->u.generic_sbp = dev;
+#endif
+
+
+       dev->driver_context = mtd;
+       param->name = mtd->name;
+
+       /* Set up the memory size parameters.... */
+
+
+       param->n_reserved_blocks = 5;
+       param->n_caches = (options.no_cache) ? 0 : 10;
+       param->inband_tags = inband_tags;
+
+       param->enable_xattr = 1;
+       if (options.lazy_loading_overridden)
+               param->disable_lazy_load = !options.lazy_loading_enabled;
+
+       param->defered_dir_update = 1;
+
+       if (options.tags_ecc_overridden)
+               param->no_tags_ecc = !options.tags_ecc_on;
+
+       param->empty_lost_n_found = 1;
+       param->refresh_period = 500;
+       param->disable_summary = options.disable_summary;
+
+
+#ifdef CONFIG_YAFFS_DISABLE_BAD_BLOCK_MARKING
+       param->disable_bad_block_marking  = 1;
+#endif
+       if (options.empty_lost_and_found_overridden)
+               param->empty_lost_n_found = options.empty_lost_and_found;
+
+       /* ... and the functions. */
+       if (yaffs_version == 2) {
+               param->is_yaffs2 = 1;
+#if (LINUX_VERSION_CODE > KERNEL_VERSION(2, 6, 17))
+               param->total_bytes_per_chunk = mtd->writesize;
+               param->chunks_per_block = mtd->erasesize / mtd->writesize;
+#else
+               param->total_bytes_per_chunk = mtd->oobblock;
+               param->chunks_per_block = mtd->erasesize / mtd->oobblock;
+#endif
+               n_blocks = YCALCBLOCKS(mtd->size, mtd->erasesize);
+
+               param->start_block = 0;
+               param->end_block = n_blocks - 1;
+       } else {
+               param->is_yaffs2 = 0;
+               n_blocks = YCALCBLOCKS(mtd->size,
+                            YAFFS_CHUNKS_PER_BLOCK * YAFFS_BYTES_PER_CHUNK);
+
+               param->chunks_per_block = YAFFS_CHUNKS_PER_BLOCK;
+               param->total_bytes_per_chunk = YAFFS_BYTES_PER_CHUNK;
+       }
+
+       param->start_block = 0;
+       param->end_block = n_blocks - 1;
+
+       yaffs_mtd_drv_install(dev);
+
+       param->sb_dirty_fn = yaffs_set_super_dirty;
+       param->gc_control_fn = yaffs_gc_control_callback;
+
+       yaffs_dev_to_lc(dev)->super = sb;
+
+       param->use_nand_ecc = 1;
+
+       param->skip_checkpt_rd = options.skip_checkpoint_read;
+       param->skip_checkpt_wr = options.skip_checkpoint_write;
+
+       mutex_lock(&yaffs_context_lock);
+       /* Get a mount id */
+       found = 0;
+       for (mount_id = 0; !found; mount_id++) {
+               found = 1;
+               list_for_each(l, &yaffs_context_list) {
+                       context_iterator =
+                           list_entry(l, struct yaffs_linux_context,
+                                      context_list);
+                       if (context_iterator->mount_id == mount_id)
+                               found = 0;
+               }
+       }
+       context->mount_id = mount_id;
+
+       list_add_tail(&(yaffs_dev_to_lc(dev)->context_list),
+                     &yaffs_context_list);
+       mutex_unlock(&yaffs_context_lock);
+
+       /* Directory search handling... */
+       INIT_LIST_HEAD(&(yaffs_dev_to_lc(dev)->search_contexts));
+       param->remove_obj_fn = yaffs_remove_obj_callback;
+
+       mutex_init(&(yaffs_dev_to_lc(dev)->gross_lock));
+
+       yaffs_gross_lock(dev);
+
+       err = yaffs_guts_initialise(dev);
+
+       yaffs_trace(YAFFS_TRACE_OS,
+               "yaffs_read_super: guts initialised %s",
+               (err == YAFFS_OK) ? "OK" : "FAILED");
+
+       if (err == YAFFS_OK)
+               yaffs_bg_start(dev);
+
+       if (!context->bg_thread)
+               param->defered_dir_update = 0;
+
+       sb->s_maxbytes = yaffs_max_file_size(dev);
+
+       /* Release lock before yaffs_get_inode() */
+       yaffs_gross_unlock(dev);
+
+       /* Create root inode */
+       if (err == YAFFS_OK)
+               inode = yaffs_get_inode(sb, S_IFDIR | 0755, 0, yaffs_root(dev));
+
+       if (!inode)
+               return NULL;
+
+       inode->i_op = &yaffs_dir_inode_operations;
+       inode->i_fop = &yaffs_dir_operations;
+
+       yaffs_trace(YAFFS_TRACE_OS, "yaffs_read_super: got root inode");
+
+       root = yaffs_make_root(inode);
+
+       if (!root)
+               return NULL;
+
+       sb->s_root = root;
+       if(!dev->is_checkpointed)
+               yaffs_set_super_dirty(dev);
+
+       yaffs_trace(YAFFS_TRACE_ALWAYS,
+               "yaffs_read_super: is_checkpointed %d",
+               dev->is_checkpointed);
+
+       yaffs_trace(YAFFS_TRACE_OS, "yaffs_read_super: done");
+       return sb;
+}
+
+#if (LINUX_VERSION_CODE > KERNEL_VERSION(2, 5, 0))
+static int yaffs_internal_read_super_mtd(struct super_block *sb, void *data,
+                                        int silent)
+{
+       return yaffs_internal_read_super(1, sb, data, silent) ? 0 : -EINVAL;
+}
+
+#if (LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 39))
+static struct dentry *yaffs_mount(struct file_system_type *fs_type, int flags,
+        const char *dev_name, void *data)
+{
+    return mount_bdev(fs_type, flags, dev_name, data, yaffs_internal_read_super_mtd);
+}
+#elif (LINUX_VERSION_CODE > KERNEL_VERSION(2, 6, 17))
+static int yaffs_read_super(struct file_system_type *fs,
+                           int flags, const char *dev_name,
+                           void *data, struct vfsmount *mnt)
+{
+
+       return get_sb_bdev(fs, flags, dev_name, data,
+                          yaffs_internal_read_super_mtd, mnt);
+}
+#else
+static struct super_block *yaffs_read_super(struct file_system_type *fs,
+                                           int flags, const char *dev_name,
+                                           void *data)
+{
+
+       return get_sb_bdev(fs, flags, dev_name, data,
+                          yaffs_internal_read_super_mtd);
+}
+#endif
+
+static struct file_system_type yaffs_fs_type = {
+       .owner = THIS_MODULE,
+       .name = "yaffs",
+#if (LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 39))
+        .mount = yaffs_mount,
+#else
+        .get_sb = yaffs_read_super,
+#endif
+       .kill_sb = kill_block_super,
+       .fs_flags = FS_REQUIRES_DEV,
+};
+#else
+static struct super_block *yaffs_read_super(struct super_block *sb, void *data,
+                                           int silent)
+{
+       return yaffs_internal_read_super(1, sb, data, silent);
+}
+
+static DECLARE_FSTYPE(yaffs_fs_type, "yaffs", yaffs_read_super,
+                     FS_REQUIRES_DEV);
+#endif
+
+
+#if (LINUX_VERSION_CODE > KERNEL_VERSION(2, 5, 0))
+static int yaffs2_internal_read_super_mtd(struct super_block *sb, void *data,
+                                         int silent)
+{
+       return yaffs_internal_read_super(2, sb, data, silent) ? 0 : -EINVAL;
+}
+
+#if (LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 39))
+static struct dentry *yaffs2_mount(struct file_system_type *fs_type, int flags,
+        const char *dev_name, void *data)
+{
+        return mount_bdev(fs_type, flags, dev_name, data, yaffs2_internal_read_super_mtd);
+}
+#elif (LINUX_VERSION_CODE > KERNEL_VERSION(2, 6, 17))
+static int yaffs2_read_super(struct file_system_type *fs,
+                            int flags, const char *dev_name, void *data,
+                            struct vfsmount *mnt)
+{
+       return get_sb_bdev(fs, flags, dev_name, data,
+                          yaffs2_internal_read_super_mtd, mnt);
+}
+#else
+static struct super_block *yaffs2_read_super(struct file_system_type *fs,
+                                            int flags, const char *dev_name,
+                                            void *data)
+{
+
+       return get_sb_bdev(fs, flags, dev_name, data,
+                          yaffs2_internal_read_super_mtd);
+}
+#endif
+
+static struct file_system_type yaffs2_fs_type = {
+       .owner = THIS_MODULE,
+       .name = "yaffs2",
+#if (LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 39))
+        .mount = yaffs2_mount,
+#else
+        .get_sb = yaffs2_read_super,
+#endif
+       .kill_sb = kill_block_super,
+       .fs_flags = FS_REQUIRES_DEV,
+};
+#else
+static struct super_block *yaffs2_read_super(struct super_block *sb,
+                                            void *data, int silent)
+{
+       return yaffs_internal_read_super(2, sb, data, silent);
+}
+
+static DECLARE_FSTYPE(yaffs2_fs_type, "yaffs2", yaffs2_read_super,
+                     FS_REQUIRES_DEV);
+#endif
+
+
+static struct proc_dir_entry *my_proc_entry;
+
+static char *yaffs_dump_dev_part0(char *buf, struct yaffs_dev *dev)
+{
+       struct yaffs_param *param = &dev->param;
+       int bs[10];
+
+       yaffs_count_blocks_by_state(dev,bs);
+
+       buf += sprintf(buf, "start_block.......... %d\n", param->start_block);
+       buf += sprintf(buf, "end_block............ %d\n", param->end_block);
+       buf += sprintf(buf, "total_bytes_per_chunk %d\n",
+                               param->total_bytes_per_chunk);
+       buf += sprintf(buf, "use_nand_ecc......... %d\n", param->use_nand_ecc);
+       buf += sprintf(buf, "no_tags_ecc.......... %d\n", param->no_tags_ecc);
+       buf += sprintf(buf, "is_yaffs2............ %d\n", param->is_yaffs2);
+       buf += sprintf(buf, "inband_tags.......... %d\n", param->inband_tags);
+       buf += sprintf(buf, "empty_lost_n_found... %d\n",
+                               param->empty_lost_n_found);
+       buf += sprintf(buf, "disable_lazy_load.... %d\n",
+                               param->disable_lazy_load);
+       buf += sprintf(buf, "disable_bad_block_mrk %d\n",
+                               param->disable_bad_block_marking);
+       buf += sprintf(buf, "refresh_period....... %d\n",
+                               param->refresh_period);
+       buf += sprintf(buf, "n_caches............. %d\n", param->n_caches);
+       buf += sprintf(buf, "n_reserved_blocks.... %d\n",
+                               param->n_reserved_blocks);
+       buf += sprintf(buf, "always_check_erased.. %d\n",
+                               param->always_check_erased);
+       buf += sprintf(buf, "\n");
+       buf += sprintf(buf, "block count by state\n");
+       buf += sprintf(buf, "0:%d 1:%d 2:%d 3:%d 4:%d\n",
+                               bs[0], bs[1], bs[2], bs[3], bs[4]);
+       buf += sprintf(buf, "5:%d 6:%d 7:%d 8:%d 9:%d\n",
+                               bs[5], bs[6], bs[7], bs[8], bs[9]);
+
+       return buf;
+}
+
+static char *yaffs_dump_dev_part1(char *buf, struct yaffs_dev *dev)
+{
+       buf += sprintf(buf, "max file size....... %lld\n",
+                               (long long) yaffs_max_file_size(dev));
+       buf += sprintf(buf, "data_bytes_per_chunk. %d\n",
+                               dev->data_bytes_per_chunk);
+       buf += sprintf(buf, "chunk_grp_bits....... %d\n", dev->chunk_grp_bits);
+       buf += sprintf(buf, "chunk_grp_size....... %d\n", dev->chunk_grp_size);
+       buf += sprintf(buf, "n_erased_blocks...... %d\n", dev->n_erased_blocks);
+       buf += sprintf(buf, "blocks_in_checkpt.... %d\n",
+                               dev->blocks_in_checkpt);
+       buf += sprintf(buf, "\n");
+       buf += sprintf(buf, "n_tnodes............. %d\n", dev->n_tnodes);
+       buf += sprintf(buf, "n_obj................ %d\n", dev->n_obj);
+       buf += sprintf(buf, "n_free_chunks........ %d\n", dev->n_free_chunks);
+       buf += sprintf(buf, "\n");
+       buf += sprintf(buf, "n_page_writes........ %u\n", dev->n_page_writes);
+       buf += sprintf(buf, "n_page_reads......... %u\n", dev->n_page_reads);
+       buf += sprintf(buf, "n_erasures........... %u\n", dev->n_erasures);
+       buf += sprintf(buf, "n_gc_copies.......... %u\n", dev->n_gc_copies);
+       buf += sprintf(buf, "all_gcs.............. %u\n", dev->all_gcs);
+       buf += sprintf(buf, "passive_gc_count..... %u\n",
+                               dev->passive_gc_count);
+       buf += sprintf(buf, "oldest_dirty_gc_count %u\n",
+                               dev->oldest_dirty_gc_count);
+       buf += sprintf(buf, "n_gc_blocks.......... %u\n", dev->n_gc_blocks);
+       buf += sprintf(buf, "bg_gcs............... %u\n", dev->bg_gcs);
+       buf += sprintf(buf, "n_retried_writes..... %u\n",
+                               dev->n_retried_writes);
+       buf += sprintf(buf, "n_retired_blocks..... %u\n",
+                               dev->n_retired_blocks);
+       buf += sprintf(buf, "n_ecc_fixed.......... %u\n", dev->n_ecc_fixed);
+       buf += sprintf(buf, "n_ecc_unfixed........ %u\n", dev->n_ecc_unfixed);
+       buf += sprintf(buf, "n_tags_ecc_fixed..... %u\n",
+                               dev->n_tags_ecc_fixed);
+       buf += sprintf(buf, "n_tags_ecc_unfixed... %u\n",
+                               dev->n_tags_ecc_unfixed);
+       buf += sprintf(buf, "cache_hits........... %u\n", dev->cache_hits);
+       buf += sprintf(buf, "n_deleted_files...... %u\n", dev->n_deleted_files);
+       buf += sprintf(buf, "n_unlinked_files..... %u\n",
+                               dev->n_unlinked_files);
+       buf += sprintf(buf, "refresh_count........ %u\n", dev->refresh_count);
+       buf += sprintf(buf, "n_bg_deletions....... %u\n", dev->n_bg_deletions);
+       buf += sprintf(buf, "tags_used............ %u\n", dev->tags_used);
+       buf += sprintf(buf, "summary_used......... %u\n", dev->summary_used);
+
+       return buf;
+}
+
+static int yaffs_proc_read(char *page,
+                          char **start,
+                          off_t offset, int count, int *eof, void *data)
+{
+       struct list_head *item;
+       char *buf = page;
+       int step = offset;
+       int n = 0;
+
+       /* Get proc_file_read() to step 'offset' by one on each sucessive call.
+        * We use 'offset' (*ppos) to indicate where we are in dev_list.
+        * This also assumes the user has posted a read buffer large
+        * enough to hold the complete output; but that's life in /proc.
+        */
+
+       *(int *)start = 1;
+
+       /* Print header first */
+       if (step == 0)
+               buf +=
+                   sprintf(buf,
+                           "Multi-version YAFFS built:" __DATE__ " " __TIME__
+                           "\n");
+       else if (step == 1)
+               buf += sprintf(buf, "\n");
+       else {
+               step -= 2;
+
+               mutex_lock(&yaffs_context_lock);
+
+               /* Locate and print the Nth entry.  Order N-squared but N is small. */
+               list_for_each(item, &yaffs_context_list) {
+                       struct yaffs_linux_context *dc =
+                           list_entry(item, struct yaffs_linux_context,
+                                      context_list);
+                       struct yaffs_dev *dev = dc->dev;
+
+                       if (n < (step & ~1)) {
+                               n += 2;
+                               continue;
+                       }
+                       if ((step & 1) == 0) {
+                               buf +=
+                                   sprintf(buf, "\nDevice %d \"%s\"\n", n,
+                                           dev->param.name);
+                               buf = yaffs_dump_dev_part0(buf, dev);
+                       } else {
+                               buf = yaffs_dump_dev_part1(buf, dev);
+                        }
+
+                       break;
+               }
+               mutex_unlock(&yaffs_context_lock);
+       }
+
+       return buf - page < count ? buf - page : count;
+}
+
+/**
+ * Set the verbosity of the warnings and error messages.
+ *
+ * Note that the names can only be a..z or _ with the current code.
+ */
+
+static struct {
+       char *mask_name;
+       unsigned mask_bitfield;
+} mask_flags[] = {
+       {"allocate", YAFFS_TRACE_ALLOCATE},
+       {"always", YAFFS_TRACE_ALWAYS},
+       {"background", YAFFS_TRACE_BACKGROUND},
+       {"bad_blocks", YAFFS_TRACE_BAD_BLOCKS},
+       {"buffers", YAFFS_TRACE_BUFFERS},
+       {"bug", YAFFS_TRACE_BUG},
+       {"checkpt", YAFFS_TRACE_CHECKPOINT},
+       {"deletion", YAFFS_TRACE_DELETION},
+       {"erase", YAFFS_TRACE_ERASE},
+       {"error", YAFFS_TRACE_ERROR},
+       {"gc_detail", YAFFS_TRACE_GC_DETAIL},
+       {"gc", YAFFS_TRACE_GC},
+       {"lock", YAFFS_TRACE_LOCK},
+       {"mtd", YAFFS_TRACE_MTD},
+       {"nandaccess", YAFFS_TRACE_NANDACCESS},
+       {"os", YAFFS_TRACE_OS},
+       {"scan_debug", YAFFS_TRACE_SCAN_DEBUG},
+       {"scan", YAFFS_TRACE_SCAN},
+       {"mount", YAFFS_TRACE_MOUNT},
+       {"tracing", YAFFS_TRACE_TRACING},
+       {"sync", YAFFS_TRACE_SYNC},
+       {"write", YAFFS_TRACE_WRITE},
+       {"verify", YAFFS_TRACE_VERIFY},
+       {"verify_nand", YAFFS_TRACE_VERIFY_NAND},
+       {"verify_full", YAFFS_TRACE_VERIFY_FULL},
+       {"verify_all", YAFFS_TRACE_VERIFY_ALL},
+       {"all", 0xffffffff},
+       {"none", 0},
+       {NULL, 0},
+};
+
+#define MAX_MASK_NAME_LENGTH 40
+static int yaffs_proc_write_trace_options(struct file *file, const char *buf,
+                                         unsigned long count, void *data)
+{
+       unsigned rg = 0, mask_bitfield;
+       char *end;
+       char *mask_name;
+       const char *x;
+       char substring[MAX_MASK_NAME_LENGTH + 1];
+       int i;
+       int done = 0;
+       int add, len = 0;
+       int pos = 0;
+
+       rg = yaffs_trace_mask;
+
+       while (!done && (pos < count)) {
+               done = 1;
+               while ((pos < count) && isspace(buf[pos]))
+                       pos++;
+
+               switch (buf[pos]) {
+               case '+':
+               case '-':
+               case '=':
+                       add = buf[pos];
+                       pos++;
+                       break;
+
+               default:
+                       add = ' ';
+                       break;
+               }
+               mask_name = NULL;
+
+               mask_bitfield = simple_strtoul(buf + pos, &end, 0);
+
+               if (end > buf + pos) {
+                       mask_name = "numeral";
+                       len = end - (buf + pos);
+                       pos += len;
+                       done = 0;
+               } else {
+                       for (x = buf + pos, i = 0;
+                            (*x == '_' || (*x >= 'a' && *x <= 'z')) &&
+                            i < MAX_MASK_NAME_LENGTH; x++, i++, pos++)
+                               substring[i] = *x;
+                       substring[i] = '\0';
+
+                       for (i = 0; mask_flags[i].mask_name != NULL; i++) {
+                               if (strcmp(substring, mask_flags[i].mask_name)
+                                   == 0) {
+                                       mask_name = mask_flags[i].mask_name;
+                                       mask_bitfield =
+                                           mask_flags[i].mask_bitfield;
+                                       done = 0;
+                                       break;
+                               }
+                       }
+               }
+
+               if (mask_name != NULL) {
+                       done = 0;
+                       switch (add) {
+                       case '-':
+                               rg &= ~mask_bitfield;
+                               break;
+                       case '+':
+                               rg |= mask_bitfield;
+                               break;
+                       case '=':
+                               rg = mask_bitfield;
+                               break;
+                       default:
+                               rg |= mask_bitfield;
+                               break;
+                       }
+               }
+       }
+
+       yaffs_trace_mask = rg | YAFFS_TRACE_ALWAYS;
+
+       printk(KERN_DEBUG "new trace = 0x%08X\n", yaffs_trace_mask);
+
+       if (rg & YAFFS_TRACE_ALWAYS) {
+               for (i = 0; mask_flags[i].mask_name != NULL; i++) {
+                       char flag;
+                       flag = ((rg & mask_flags[i].mask_bitfield) ==
+                               mask_flags[i].mask_bitfield) ? '+' : '-';
+                       printk(KERN_DEBUG "%c%s\n", flag,
+                              mask_flags[i].mask_name);
+               }
+       }
+
+       return count;
+}
+
+/* Debug strings are of the form:
+ * .bnnn         print info on block n
+ * .cobjn,chunkn print nand chunk id for objn:chunkn
+ */
+
+static int yaffs_proc_debug_write(struct file *file, const char *buf,
+                                         unsigned long count, void *data)
+{
+
+       char str[100];
+       char *p0;
+       char *p1;
+       long p1_val;
+       long p0_val;
+       char cmd;
+       struct list_head *item;
+
+       memset(str, 0, sizeof(str));
+       memcpy(str, buf, min(count, sizeof(str) -1));
+
+       cmd = str[1];
+
+       p0 = str + 2;
+
+       p1 = p0;
+
+       while (*p1 && *p1 != ',') {
+               p1++;
+       }
+       *p1 = '\0';
+       p1++;
+
+       p0_val = simple_strtol(p0, NULL, 0);
+       p1_val = simple_strtol(p1, NULL, 0);
+
+
+       mutex_lock(&yaffs_context_lock);
+
+       /* Locate and print the Nth entry.  Order N-squared but N is small. */
+       list_for_each(item, &yaffs_context_list) {
+               struct yaffs_linux_context *dc =
+                   list_entry(item, struct yaffs_linux_context,
+                              context_list);
+               struct yaffs_dev *dev = dc->dev;
+
+               if (cmd == 'b') {
+                       struct yaffs_block_info *bi;
+
+                       bi = yaffs_get_block_info(dev,p0_val);
+
+                       if(bi) {
+                               printk("Block %d: state %d, retire %d, use %d, seq %d\n",
+                                       (int)p0_val, bi->block_state,
+                                       bi->needs_retiring, bi->pages_in_use,
+                                       bi->seq_number);
+                       }
+               } else if (cmd == 'c') {
+                       struct yaffs_obj *obj;
+                       int nand_chunk;
+
+                       obj = yaffs_find_by_number(dev, p0_val);
+                       if (!obj)
+                               printk("No obj %d\n", (int)p0_val);
+                       else {
+                               if(p1_val == 0)
+                                       nand_chunk = obj->hdr_chunk;
+                               else
+                                       nand_chunk =
+                                               yaffs_find_chunk_in_file(obj,
+                                                       p1_val, NULL);
+                               printk("Nand chunk for %d:%d is %d\n",
+                                       (int)p0_val, (int)p1_val, nand_chunk);
+                       }
+               }
+       }
+
+       mutex_unlock(&yaffs_context_lock);
+
+       return count;
+}
+
+static int yaffs_proc_write(struct file *file, const char *buf,
+                           unsigned long count, void *data)
+{
+       if (buf[0] == '.')
+               return yaffs_proc_debug_write(file, buf, count, data);
+       return yaffs_proc_write_trace_options(file, buf, count, data);
+}
+
+/* Stuff to handle installation of file systems */
+struct file_system_to_install {
+       struct file_system_type *fst;
+       int installed;
+};
+
+static struct file_system_to_install fs_to_install[] = {
+       {&yaffs_fs_type, 0},
+       {&yaffs2_fs_type, 0},
+       {NULL, 0}
+};
+
+static int __init init_yaffs_fs(void)
+{
+       int error = 0;
+       struct file_system_to_install *fsinst;
+
+       yaffs_trace(YAFFS_TRACE_ALWAYS,
+               "yaffs built " __DATE__ " " __TIME__ " Installing.");
+
+       mutex_init(&yaffs_context_lock);
+
+       /* Install the proc_fs entries */
+       my_proc_entry = create_proc_entry("yaffs",
+                                         S_IRUGO | S_IFREG, YPROC_ROOT);
+
+       if (my_proc_entry) {
+               my_proc_entry->write_proc = yaffs_proc_write;
+               my_proc_entry->read_proc = yaffs_proc_read;
+               my_proc_entry->data = NULL;
+       } else {
+               return -ENOMEM;
+        }
+
+       /* Now add the file system entries */
+
+       fsinst = fs_to_install;
+
+       while (fsinst->fst && !error) {
+               error = register_filesystem(fsinst->fst);
+               if (!error)
+                       fsinst->installed = 1;
+               fsinst++;
+       }
+
+       /* Any errors? uninstall  */
+       if (error) {
+               fsinst = fs_to_install;
+
+               while (fsinst->fst) {
+                       if (fsinst->installed) {
+                               unregister_filesystem(fsinst->fst);
+                               fsinst->installed = 0;
+                       }
+                       fsinst++;
+               }
+       }
+
+       return error;
+}
+
+static void __exit exit_yaffs_fs(void)
+{
+
+       struct file_system_to_install *fsinst;
+
+       yaffs_trace(YAFFS_TRACE_ALWAYS,
+               "yaffs built " __DATE__ " " __TIME__ " removing.");
+
+       remove_proc_entry("yaffs", YPROC_ROOT);
+
+       fsinst = fs_to_install;
+
+       while (fsinst->fst) {
+               if (fsinst->installed) {
+                       unregister_filesystem(fsinst->fst);
+                       fsinst->installed = 0;
+               }
+               fsinst++;
+       }
+}
+
+module_init(init_yaffs_fs)
+    module_exit(exit_yaffs_fs)
+
+    MODULE_DESCRIPTION("YAFFS2 - a NAND specific flash file system");
+MODULE_AUTHOR("Charles Manning, Aleph One Ltd., 2002-2011");
+MODULE_LICENSE("GPL");