Add the rt linux 4.1.3-rt3 as base
[kvmfornfv.git] / kernel / fs / jffs2 / wbuf.c
diff --git a/kernel/fs/jffs2/wbuf.c b/kernel/fs/jffs2/wbuf.c
new file mode 100644 (file)
index 0000000..09ed551
--- /dev/null
@@ -0,0 +1,1353 @@
+/*
+ * JFFS2 -- Journalling Flash File System, Version 2.
+ *
+ * Copyright © 2001-2007 Red Hat, Inc.
+ * Copyright © 2004 Thomas Gleixner <tglx@linutronix.de>
+ *
+ * Created by David Woodhouse <dwmw2@infradead.org>
+ * Modified debugged and enhanced by Thomas Gleixner <tglx@linutronix.de>
+ *
+ * For licensing information, see the file 'LICENCE' in this directory.
+ *
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/kernel.h>
+#include <linux/slab.h>
+#include <linux/mtd/mtd.h>
+#include <linux/crc32.h>
+#include <linux/mtd/nand.h>
+#include <linux/jiffies.h>
+#include <linux/sched.h>
+#include <linux/writeback.h>
+
+#include "nodelist.h"
+
+/* For testing write failures */
+#undef BREAKME
+#undef BREAKMEHEADER
+
+#ifdef BREAKME
+static unsigned char *brokenbuf;
+#endif
+
+#define PAGE_DIV(x) ( ((unsigned long)(x) / (unsigned long)(c->wbuf_pagesize)) * (unsigned long)(c->wbuf_pagesize) )
+#define PAGE_MOD(x) ( (unsigned long)(x) % (unsigned long)(c->wbuf_pagesize) )
+
+/* max. erase failures before we mark a block bad */
+#define MAX_ERASE_FAILURES     2
+
+struct jffs2_inodirty {
+       uint32_t ino;
+       struct jffs2_inodirty *next;
+};
+
+static struct jffs2_inodirty inodirty_nomem;
+
+static int jffs2_wbuf_pending_for_ino(struct jffs2_sb_info *c, uint32_t ino)
+{
+       struct jffs2_inodirty *this = c->wbuf_inodes;
+
+       /* If a malloc failed, consider _everything_ dirty */
+       if (this == &inodirty_nomem)
+               return 1;
+
+       /* If ino == 0, _any_ non-GC writes mean 'yes' */
+       if (this && !ino)
+               return 1;
+
+       /* Look to see if the inode in question is pending in the wbuf */
+       while (this) {
+               if (this->ino == ino)
+                       return 1;
+               this = this->next;
+       }
+       return 0;
+}
+
+static void jffs2_clear_wbuf_ino_list(struct jffs2_sb_info *c)
+{
+       struct jffs2_inodirty *this;
+
+       this = c->wbuf_inodes;
+
+       if (this != &inodirty_nomem) {
+               while (this) {
+                       struct jffs2_inodirty *next = this->next;
+                       kfree(this);
+                       this = next;
+               }
+       }
+       c->wbuf_inodes = NULL;
+}
+
+static void jffs2_wbuf_dirties_inode(struct jffs2_sb_info *c, uint32_t ino)
+{
+       struct jffs2_inodirty *new;
+
+       /* Schedule delayed write-buffer write-out */
+       jffs2_dirty_trigger(c);
+
+       if (jffs2_wbuf_pending_for_ino(c, ino))
+               return;
+
+       new = kmalloc(sizeof(*new), GFP_KERNEL);
+       if (!new) {
+               jffs2_dbg(1, "No memory to allocate inodirty. Fallback to all considered dirty\n");
+               jffs2_clear_wbuf_ino_list(c);
+               c->wbuf_inodes = &inodirty_nomem;
+               return;
+       }
+       new->ino = ino;
+       new->next = c->wbuf_inodes;
+       c->wbuf_inodes = new;
+       return;
+}
+
+static inline void jffs2_refile_wbuf_blocks(struct jffs2_sb_info *c)
+{
+       struct list_head *this, *next;
+       static int n;
+
+       if (list_empty(&c->erasable_pending_wbuf_list))
+               return;
+
+       list_for_each_safe(this, next, &c->erasable_pending_wbuf_list) {
+               struct jffs2_eraseblock *jeb = list_entry(this, struct jffs2_eraseblock, list);
+
+               jffs2_dbg(1, "Removing eraseblock at 0x%08x from erasable_pending_wbuf_list...\n",
+                         jeb->offset);
+               list_del(this);
+               if ((jiffies + (n++)) & 127) {
+                       /* Most of the time, we just erase it immediately. Otherwise we
+                          spend ages scanning it on mount, etc. */
+                       jffs2_dbg(1, "...and adding to erase_pending_list\n");
+                       list_add_tail(&jeb->list, &c->erase_pending_list);
+                       c->nr_erasing_blocks++;
+                       jffs2_garbage_collect_trigger(c);
+               } else {
+                       /* Sometimes, however, we leave it elsewhere so it doesn't get
+                          immediately reused, and we spread the load a bit. */
+                       jffs2_dbg(1, "...and adding to erasable_list\n");
+                       list_add_tail(&jeb->list, &c->erasable_list);
+               }
+       }
+}
+
+#define REFILE_NOTEMPTY 0
+#define REFILE_ANYWAY   1
+
+static void jffs2_block_refile(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb, int allow_empty)
+{
+       jffs2_dbg(1, "About to refile bad block at %08x\n", jeb->offset);
+
+       /* File the existing block on the bad_used_list.... */
+       if (c->nextblock == jeb)
+               c->nextblock = NULL;
+       else /* Not sure this should ever happen... need more coffee */
+               list_del(&jeb->list);
+       if (jeb->first_node) {
+               jffs2_dbg(1, "Refiling block at %08x to bad_used_list\n",
+                         jeb->offset);
+               list_add(&jeb->list, &c->bad_used_list);
+       } else {
+               BUG_ON(allow_empty == REFILE_NOTEMPTY);
+               /* It has to have had some nodes or we couldn't be here */
+               jffs2_dbg(1, "Refiling block at %08x to erase_pending_list\n",
+                         jeb->offset);
+               list_add(&jeb->list, &c->erase_pending_list);
+               c->nr_erasing_blocks++;
+               jffs2_garbage_collect_trigger(c);
+       }
+
+       if (!jffs2_prealloc_raw_node_refs(c, jeb, 1)) {
+               uint32_t oldfree = jeb->free_size;
+
+               jffs2_link_node_ref(c, jeb, 
+                                   (jeb->offset+c->sector_size-oldfree) | REF_OBSOLETE,
+                                   oldfree, NULL);
+               /* convert to wasted */
+               c->wasted_size += oldfree;
+               jeb->wasted_size += oldfree;
+               c->dirty_size -= oldfree;
+               jeb->dirty_size -= oldfree;
+       }
+
+       jffs2_dbg_dump_block_lists_nolock(c);
+       jffs2_dbg_acct_sanity_check_nolock(c,jeb);
+       jffs2_dbg_acct_paranoia_check_nolock(c, jeb);
+}
+
+static struct jffs2_raw_node_ref **jffs2_incore_replace_raw(struct jffs2_sb_info *c,
+                                                           struct jffs2_inode_info *f,
+                                                           struct jffs2_raw_node_ref *raw,
+                                                           union jffs2_node_union *node)
+{
+       struct jffs2_node_frag *frag;
+       struct jffs2_full_dirent *fd;
+
+       dbg_noderef("incore_replace_raw: node at %p is {%04x,%04x}\n",
+                   node, je16_to_cpu(node->u.magic), je16_to_cpu(node->u.nodetype));
+
+       BUG_ON(je16_to_cpu(node->u.magic) != 0x1985 &&
+              je16_to_cpu(node->u.magic) != 0);
+
+       switch (je16_to_cpu(node->u.nodetype)) {
+       case JFFS2_NODETYPE_INODE:
+               if (f->metadata && f->metadata->raw == raw) {
+                       dbg_noderef("Will replace ->raw in f->metadata at %p\n", f->metadata);
+                       return &f->metadata->raw;
+               }
+               frag = jffs2_lookup_node_frag(&f->fragtree, je32_to_cpu(node->i.offset));
+               BUG_ON(!frag);
+               /* Find a frag which refers to the full_dnode we want to modify */
+               while (!frag->node || frag->node->raw != raw) {
+                       frag = frag_next(frag);
+                       BUG_ON(!frag);
+               }
+               dbg_noderef("Will replace ->raw in full_dnode at %p\n", frag->node);
+               return &frag->node->raw;
+
+       case JFFS2_NODETYPE_DIRENT:
+               for (fd = f->dents; fd; fd = fd->next) {
+                       if (fd->raw == raw) {
+                               dbg_noderef("Will replace ->raw in full_dirent at %p\n", fd);
+                               return &fd->raw;
+                       }
+               }
+               BUG();
+
+       default:
+               dbg_noderef("Don't care about replacing raw for nodetype %x\n",
+                           je16_to_cpu(node->u.nodetype));
+               break;
+       }
+       return NULL;
+}
+
+#ifdef CONFIG_JFFS2_FS_WBUF_VERIFY
+static int jffs2_verify_write(struct jffs2_sb_info *c, unsigned char *buf,
+                             uint32_t ofs)
+{
+       int ret;
+       size_t retlen;
+       char *eccstr;
+
+       ret = mtd_read(c->mtd, ofs, c->wbuf_pagesize, &retlen, c->wbuf_verify);
+       if (ret && ret != -EUCLEAN && ret != -EBADMSG) {
+               pr_warn("%s(): Read back of page at %08x failed: %d\n",
+                       __func__, c->wbuf_ofs, ret);
+               return ret;
+       } else if (retlen != c->wbuf_pagesize) {
+               pr_warn("%s(): Read back of page at %08x gave short read: %zd not %d\n",
+                       __func__, ofs, retlen, c->wbuf_pagesize);
+               return -EIO;
+       }
+       if (!memcmp(buf, c->wbuf_verify, c->wbuf_pagesize))
+               return 0;
+
+       if (ret == -EUCLEAN)
+               eccstr = "corrected";
+       else if (ret == -EBADMSG)
+               eccstr = "correction failed";
+       else
+               eccstr = "OK or unused";
+
+       pr_warn("Write verify error (ECC %s) at %08x. Wrote:\n",
+               eccstr, c->wbuf_ofs);
+       print_hex_dump(KERN_WARNING, "", DUMP_PREFIX_OFFSET, 16, 1,
+                      c->wbuf, c->wbuf_pagesize, 0);
+
+       pr_warn("Read back:\n");
+       print_hex_dump(KERN_WARNING, "", DUMP_PREFIX_OFFSET, 16, 1,
+                      c->wbuf_verify, c->wbuf_pagesize, 0);
+
+       return -EIO;
+}
+#else
+#define jffs2_verify_write(c,b,o) (0)
+#endif
+
+/* Recover from failure to write wbuf. Recover the nodes up to the
+ * wbuf, not the one which we were starting to try to write. */
+
+static void jffs2_wbuf_recover(struct jffs2_sb_info *c)
+{
+       struct jffs2_eraseblock *jeb, *new_jeb;
+       struct jffs2_raw_node_ref *raw, *next, *first_raw = NULL;
+       size_t retlen;
+       int ret;
+       int nr_refile = 0;
+       unsigned char *buf;
+       uint32_t start, end, ofs, len;
+
+       jeb = &c->blocks[c->wbuf_ofs / c->sector_size];
+
+       spin_lock(&c->erase_completion_lock);
+       if (c->wbuf_ofs % c->mtd->erasesize)
+               jffs2_block_refile(c, jeb, REFILE_NOTEMPTY);
+       else
+               jffs2_block_refile(c, jeb, REFILE_ANYWAY);
+       spin_unlock(&c->erase_completion_lock);
+
+       BUG_ON(!ref_obsolete(jeb->last_node));
+
+       /* Find the first node to be recovered, by skipping over every
+          node which ends before the wbuf starts, or which is obsolete. */
+       for (next = raw = jeb->first_node; next; raw = next) {
+               next = ref_next(raw);
+
+               if (ref_obsolete(raw) || 
+                   (next && ref_offset(next) <= c->wbuf_ofs)) {
+                       dbg_noderef("Skipping node at 0x%08x(%d)-0x%08x which is either before 0x%08x or obsolete\n",
+                                   ref_offset(raw), ref_flags(raw),
+                                   (ref_offset(raw) + ref_totlen(c, jeb, raw)),
+                                   c->wbuf_ofs);
+                       continue;
+               }
+               dbg_noderef("First node to be recovered is at 0x%08x(%d)-0x%08x\n",
+                           ref_offset(raw), ref_flags(raw),
+                           (ref_offset(raw) + ref_totlen(c, jeb, raw)));
+
+               first_raw = raw;
+               break;
+       }
+
+       if (!first_raw) {
+               /* All nodes were obsolete. Nothing to recover. */
+               jffs2_dbg(1, "No non-obsolete nodes to be recovered. Just filing block bad\n");
+               c->wbuf_len = 0;
+               return;
+       }
+
+       start = ref_offset(first_raw);
+       end = ref_offset(jeb->last_node);
+       nr_refile = 1;
+
+       /* Count the number of refs which need to be copied */
+       while ((raw = ref_next(raw)) != jeb->last_node)
+               nr_refile++;
+
+       dbg_noderef("wbuf recover %08x-%08x (%d bytes in %d nodes)\n",
+                   start, end, end - start, nr_refile);
+
+       buf = NULL;
+       if (start < c->wbuf_ofs) {
+               /* First affected node was already partially written.
+                * Attempt to reread the old data into our buffer. */
+
+               buf = kmalloc(end - start, GFP_KERNEL);
+               if (!buf) {
+                       pr_crit("Malloc failure in wbuf recovery. Data loss ensues.\n");
+
+                       goto read_failed;
+               }
+
+               /* Do the read... */
+               ret = mtd_read(c->mtd, start, c->wbuf_ofs - start, &retlen,
+                              buf);
+
+               /* ECC recovered ? */
+               if ((ret == -EUCLEAN || ret == -EBADMSG) &&
+                   (retlen == c->wbuf_ofs - start))
+                       ret = 0;
+
+               if (ret || retlen != c->wbuf_ofs - start) {
+                       pr_crit("Old data are already lost in wbuf recovery. Data loss ensues.\n");
+
+                       kfree(buf);
+                       buf = NULL;
+               read_failed:
+                       first_raw = ref_next(first_raw);
+                       nr_refile--;
+                       while (first_raw && ref_obsolete(first_raw)) {
+                               first_raw = ref_next(first_raw);
+                               nr_refile--;
+                       }
+
+                       /* If this was the only node to be recovered, give up */
+                       if (!first_raw) {
+                               c->wbuf_len = 0;
+                               return;
+                       }
+
+                       /* It wasn't. Go on and try to recover nodes complete in the wbuf */
+                       start = ref_offset(first_raw);
+                       dbg_noderef("wbuf now recover %08x-%08x (%d bytes in %d nodes)\n",
+                                   start, end, end - start, nr_refile);
+
+               } else {
+                       /* Read succeeded. Copy the remaining data from the wbuf */
+                       memcpy(buf + (c->wbuf_ofs - start), c->wbuf, end - c->wbuf_ofs);
+               }
+       }
+       /* OK... we're to rewrite (end-start) bytes of data from first_raw onwards.
+          Either 'buf' contains the data, or we find it in the wbuf */
+
+       /* ... and get an allocation of space from a shiny new block instead */
+       ret = jffs2_reserve_space_gc(c, end-start, &len, JFFS2_SUMMARY_NOSUM_SIZE);
+       if (ret) {
+               pr_warn("Failed to allocate space for wbuf recovery. Data loss ensues.\n");
+               kfree(buf);
+               return;
+       }
+
+       /* The summary is not recovered, so it must be disabled for this erase block */
+       jffs2_sum_disable_collecting(c->summary);
+
+       ret = jffs2_prealloc_raw_node_refs(c, c->nextblock, nr_refile);
+       if (ret) {
+               pr_warn("Failed to allocate node refs for wbuf recovery. Data loss ensues.\n");
+               kfree(buf);
+               return;
+       }
+
+       ofs = write_ofs(c);
+
+       if (end-start >= c->wbuf_pagesize) {
+               /* Need to do another write immediately, but it's possible
+                  that this is just because the wbuf itself is completely
+                  full, and there's nothing earlier read back from the
+                  flash. Hence 'buf' isn't necessarily what we're writing
+                  from. */
+               unsigned char *rewrite_buf = buf?:c->wbuf;
+               uint32_t towrite = (end-start) - ((end-start)%c->wbuf_pagesize);
+
+               jffs2_dbg(1, "Write 0x%x bytes at 0x%08x in wbuf recover\n",
+                         towrite, ofs);
+
+#ifdef BREAKMEHEADER
+               static int breakme;
+               if (breakme++ == 20) {
+                       pr_notice("Faking write error at 0x%08x\n", ofs);
+                       breakme = 0;
+                       mtd_write(c->mtd, ofs, towrite, &retlen, brokenbuf);
+                       ret = -EIO;
+               } else
+#endif
+                       ret = mtd_write(c->mtd, ofs, towrite, &retlen,
+                                       rewrite_buf);
+
+               if (ret || retlen != towrite || jffs2_verify_write(c, rewrite_buf, ofs)) {
+                       /* Argh. We tried. Really we did. */
+                       pr_crit("Recovery of wbuf failed due to a second write error\n");
+                       kfree(buf);
+
+                       if (retlen)
+                               jffs2_add_physical_node_ref(c, ofs | REF_OBSOLETE, ref_totlen(c, jeb, first_raw), NULL);
+
+                       return;
+               }
+               pr_notice("Recovery of wbuf succeeded to %08x\n", ofs);
+
+               c->wbuf_len = (end - start) - towrite;
+               c->wbuf_ofs = ofs + towrite;
+               memmove(c->wbuf, rewrite_buf + towrite, c->wbuf_len);
+               /* Don't muck about with c->wbuf_inodes. False positives are harmless. */
+       } else {
+               /* OK, now we're left with the dregs in whichever buffer we're using */
+               if (buf) {
+                       memcpy(c->wbuf, buf, end-start);
+               } else {
+                       memmove(c->wbuf, c->wbuf + (start - c->wbuf_ofs), end - start);
+               }
+               c->wbuf_ofs = ofs;
+               c->wbuf_len = end - start;
+       }
+
+       /* Now sort out the jffs2_raw_node_refs, moving them from the old to the next block */
+       new_jeb = &c->blocks[ofs / c->sector_size];
+
+       spin_lock(&c->erase_completion_lock);
+       for (raw = first_raw; raw != jeb->last_node; raw = ref_next(raw)) {
+               uint32_t rawlen = ref_totlen(c, jeb, raw);
+               struct jffs2_inode_cache *ic;
+               struct jffs2_raw_node_ref *new_ref;
+               struct jffs2_raw_node_ref **adjust_ref = NULL;
+               struct jffs2_inode_info *f = NULL;
+
+               jffs2_dbg(1, "Refiling block of %08x at %08x(%d) to %08x\n",
+                         rawlen, ref_offset(raw), ref_flags(raw), ofs);
+
+               ic = jffs2_raw_ref_to_ic(raw);
+
+               /* Ick. This XATTR mess should be fixed shortly... */
+               if (ic && ic->class == RAWNODE_CLASS_XATTR_DATUM) {
+                       struct jffs2_xattr_datum *xd = (void *)ic;
+                       BUG_ON(xd->node != raw);
+                       adjust_ref = &xd->node;
+                       raw->next_in_ino = NULL;
+                       ic = NULL;
+               } else if (ic && ic->class == RAWNODE_CLASS_XATTR_REF) {
+                       struct jffs2_xattr_datum *xr = (void *)ic;
+                       BUG_ON(xr->node != raw);
+                       adjust_ref = &xr->node;
+                       raw->next_in_ino = NULL;
+                       ic = NULL;
+               } else if (ic && ic->class == RAWNODE_CLASS_INODE_CACHE) {
+                       struct jffs2_raw_node_ref **p = &ic->nodes;
+
+                       /* Remove the old node from the per-inode list */
+                       while (*p && *p != (void *)ic) {
+                               if (*p == raw) {
+                                       (*p) = (raw->next_in_ino);
+                                       raw->next_in_ino = NULL;
+                                       break;
+                               }
+                               p = &((*p)->next_in_ino);
+                       }
+
+                       if (ic->state == INO_STATE_PRESENT && !ref_obsolete(raw)) {
+                               /* If it's an in-core inode, then we have to adjust any
+                                  full_dirent or full_dnode structure to point to the
+                                  new version instead of the old */
+                               f = jffs2_gc_fetch_inode(c, ic->ino, !ic->pino_nlink);
+                               if (IS_ERR(f)) {
+                                       /* Should never happen; it _must_ be present */
+                                       JFFS2_ERROR("Failed to iget() ino #%u, err %ld\n",
+                                                   ic->ino, PTR_ERR(f));
+                                       BUG();
+                               }
+                               /* We don't lock f->sem. There's a number of ways we could
+                                  end up in here with it already being locked, and nobody's
+                                  going to modify it on us anyway because we hold the
+                                  alloc_sem. We're only changing one ->raw pointer too,
+                                  which we can get away with without upsetting readers. */
+                               adjust_ref = jffs2_incore_replace_raw(c, f, raw,
+                                                                     (void *)(buf?:c->wbuf) + (ref_offset(raw) - start));
+                       } else if (unlikely(ic->state != INO_STATE_PRESENT &&
+                                           ic->state != INO_STATE_CHECKEDABSENT &&
+                                           ic->state != INO_STATE_GC)) {
+                               JFFS2_ERROR("Inode #%u is in strange state %d!\n", ic->ino, ic->state);
+                               BUG();
+                       }
+               }
+
+               new_ref = jffs2_link_node_ref(c, new_jeb, ofs | ref_flags(raw), rawlen, ic);
+
+               if (adjust_ref) {
+                       BUG_ON(*adjust_ref != raw);
+                       *adjust_ref = new_ref;
+               }
+               if (f)
+                       jffs2_gc_release_inode(c, f);
+
+               if (!ref_obsolete(raw)) {
+                       jeb->dirty_size += rawlen;
+                       jeb->used_size  -= rawlen;
+                       c->dirty_size += rawlen;
+                       c->used_size -= rawlen;
+                       raw->flash_offset = ref_offset(raw) | REF_OBSOLETE;
+                       BUG_ON(raw->next_in_ino);
+               }
+               ofs += rawlen;
+       }
+
+       kfree(buf);
+
+       /* Fix up the original jeb now it's on the bad_list */
+       if (first_raw == jeb->first_node) {
+               jffs2_dbg(1, "Failing block at %08x is now empty. Moving to erase_pending_list\n",
+                         jeb->offset);
+               list_move(&jeb->list, &c->erase_pending_list);
+               c->nr_erasing_blocks++;
+               jffs2_garbage_collect_trigger(c);
+       }
+
+       jffs2_dbg_acct_sanity_check_nolock(c, jeb);
+       jffs2_dbg_acct_paranoia_check_nolock(c, jeb);
+
+       jffs2_dbg_acct_sanity_check_nolock(c, new_jeb);
+       jffs2_dbg_acct_paranoia_check_nolock(c, new_jeb);
+
+       spin_unlock(&c->erase_completion_lock);
+
+       jffs2_dbg(1, "wbuf recovery completed OK. wbuf_ofs 0x%08x, len 0x%x\n",
+                 c->wbuf_ofs, c->wbuf_len);
+
+}
+
+/* Meaning of pad argument:
+   0: Do not pad. Probably pointless - we only ever use this when we can't pad anyway.
+   1: Pad, do not adjust nextblock free_size
+   2: Pad, adjust nextblock free_size
+*/
+#define NOPAD          0
+#define PAD_NOACCOUNT  1
+#define PAD_ACCOUNTING 2
+
+static int __jffs2_flush_wbuf(struct jffs2_sb_info *c, int pad)
+{
+       struct jffs2_eraseblock *wbuf_jeb;
+       int ret;
+       size_t retlen;
+
+       /* Nothing to do if not write-buffering the flash. In particular, we shouldn't
+          del_timer() the timer we never initialised. */
+       if (!jffs2_is_writebuffered(c))
+               return 0;
+
+       if (!mutex_is_locked(&c->alloc_sem)) {
+               pr_crit("jffs2_flush_wbuf() called with alloc_sem not locked!\n");
+               BUG();
+       }
+
+       if (!c->wbuf_len)       /* already checked c->wbuf above */
+               return 0;
+
+       wbuf_jeb = &c->blocks[c->wbuf_ofs / c->sector_size];
+       if (jffs2_prealloc_raw_node_refs(c, wbuf_jeb, c->nextblock->allocated_refs + 1))
+               return -ENOMEM;
+
+       /* claim remaining space on the page
+          this happens, if we have a change to a new block,
+          or if fsync forces us to flush the writebuffer.
+          if we have a switch to next page, we will not have
+          enough remaining space for this.
+       */
+       if (pad ) {
+               c->wbuf_len = PAD(c->wbuf_len);
+
+               /* Pad with JFFS2_DIRTY_BITMASK initially.  this helps out ECC'd NOR
+                  with 8 byte page size */
+               memset(c->wbuf + c->wbuf_len, 0, c->wbuf_pagesize - c->wbuf_len);
+
+               if ( c->wbuf_len + sizeof(struct jffs2_unknown_node) < c->wbuf_pagesize) {
+                       struct jffs2_unknown_node *padnode = (void *)(c->wbuf + c->wbuf_len);
+                       padnode->magic = cpu_to_je16(JFFS2_MAGIC_BITMASK);
+                       padnode->nodetype = cpu_to_je16(JFFS2_NODETYPE_PADDING);
+                       padnode->totlen = cpu_to_je32(c->wbuf_pagesize - c->wbuf_len);
+                       padnode->hdr_crc = cpu_to_je32(crc32(0, padnode, sizeof(*padnode)-4));
+               }
+       }
+       /* else jffs2_flash_writev has actually filled in the rest of the
+          buffer for us, and will deal with the node refs etc. later. */
+
+#ifdef BREAKME
+       static int breakme;
+       if (breakme++ == 20) {
+               pr_notice("Faking write error at 0x%08x\n", c->wbuf_ofs);
+               breakme = 0;
+               mtd_write(c->mtd, c->wbuf_ofs, c->wbuf_pagesize, &retlen,
+                         brokenbuf);
+               ret = -EIO;
+       } else
+#endif
+
+               ret = mtd_write(c->mtd, c->wbuf_ofs, c->wbuf_pagesize,
+                               &retlen, c->wbuf);
+
+       if (ret) {
+               pr_warn("jffs2_flush_wbuf(): Write failed with %d\n", ret);
+               goto wfail;
+       } else if (retlen != c->wbuf_pagesize) {
+               pr_warn("jffs2_flush_wbuf(): Write was short: %zd instead of %d\n",
+                       retlen, c->wbuf_pagesize);
+               ret = -EIO;
+               goto wfail;
+       } else if ((ret = jffs2_verify_write(c, c->wbuf, c->wbuf_ofs))) {
+       wfail:
+               jffs2_wbuf_recover(c);
+
+               return ret;
+       }
+
+       /* Adjust free size of the block if we padded. */
+       if (pad) {
+               uint32_t waste = c->wbuf_pagesize - c->wbuf_len;
+
+               jffs2_dbg(1, "jffs2_flush_wbuf() adjusting free_size of %sblock at %08x\n",
+                         (wbuf_jeb == c->nextblock) ? "next" : "",
+                         wbuf_jeb->offset);
+
+               /* wbuf_pagesize - wbuf_len is the amount of space that's to be
+                  padded. If there is less free space in the block than that,
+                  something screwed up */
+               if (wbuf_jeb->free_size < waste) {
+                       pr_crit("jffs2_flush_wbuf(): Accounting error. wbuf at 0x%08x has 0x%03x bytes, 0x%03x left.\n",
+                               c->wbuf_ofs, c->wbuf_len, waste);
+                       pr_crit("jffs2_flush_wbuf(): But free_size for block at 0x%08x is only 0x%08x\n",
+                               wbuf_jeb->offset, wbuf_jeb->free_size);
+                       BUG();
+               }
+
+               spin_lock(&c->erase_completion_lock);
+
+               jffs2_link_node_ref(c, wbuf_jeb, (c->wbuf_ofs + c->wbuf_len) | REF_OBSOLETE, waste, NULL);
+               /* FIXME: that made it count as dirty. Convert to wasted */
+               wbuf_jeb->dirty_size -= waste;
+               c->dirty_size -= waste;
+               wbuf_jeb->wasted_size += waste;
+               c->wasted_size += waste;
+       } else
+               spin_lock(&c->erase_completion_lock);
+
+       /* Stick any now-obsoleted blocks on the erase_pending_list */
+       jffs2_refile_wbuf_blocks(c);
+       jffs2_clear_wbuf_ino_list(c);
+       spin_unlock(&c->erase_completion_lock);
+
+       memset(c->wbuf,0xff,c->wbuf_pagesize);
+       /* adjust write buffer offset, else we get a non contiguous write bug */
+       c->wbuf_ofs += c->wbuf_pagesize;
+       c->wbuf_len = 0;
+       return 0;
+}
+
+/* Trigger garbage collection to flush the write-buffer.
+   If ino arg is zero, do it if _any_ real (i.e. not GC) writes are
+   outstanding. If ino arg non-zero, do it only if a write for the
+   given inode is outstanding. */
+int jffs2_flush_wbuf_gc(struct jffs2_sb_info *c, uint32_t ino)
+{
+       uint32_t old_wbuf_ofs;
+       uint32_t old_wbuf_len;
+       int ret = 0;
+
+       jffs2_dbg(1, "jffs2_flush_wbuf_gc() called for ino #%u...\n", ino);
+
+       if (!c->wbuf)
+               return 0;
+
+       mutex_lock(&c->alloc_sem);
+       if (!jffs2_wbuf_pending_for_ino(c, ino)) {
+               jffs2_dbg(1, "Ino #%d not pending in wbuf. Returning\n", ino);
+               mutex_unlock(&c->alloc_sem);
+               return 0;
+       }
+
+       old_wbuf_ofs = c->wbuf_ofs;
+       old_wbuf_len = c->wbuf_len;
+
+       if (c->unchecked_size) {
+               /* GC won't make any progress for a while */
+               jffs2_dbg(1, "%s(): padding. Not finished checking\n",
+                         __func__);
+               down_write(&c->wbuf_sem);
+               ret = __jffs2_flush_wbuf(c, PAD_ACCOUNTING);
+               /* retry flushing wbuf in case jffs2_wbuf_recover
+                  left some data in the wbuf */
+               if (ret)
+                       ret = __jffs2_flush_wbuf(c, PAD_ACCOUNTING);
+               up_write(&c->wbuf_sem);
+       } else while (old_wbuf_len &&
+                     old_wbuf_ofs == c->wbuf_ofs) {
+
+               mutex_unlock(&c->alloc_sem);
+
+               jffs2_dbg(1, "%s(): calls gc pass\n", __func__);
+
+               ret = jffs2_garbage_collect_pass(c);
+               if (ret) {
+                       /* GC failed. Flush it with padding instead */
+                       mutex_lock(&c->alloc_sem);
+                       down_write(&c->wbuf_sem);
+                       ret = __jffs2_flush_wbuf(c, PAD_ACCOUNTING);
+                       /* retry flushing wbuf in case jffs2_wbuf_recover
+                          left some data in the wbuf */
+                       if (ret)
+                               ret = __jffs2_flush_wbuf(c, PAD_ACCOUNTING);
+                       up_write(&c->wbuf_sem);
+                       break;
+               }
+               mutex_lock(&c->alloc_sem);
+       }
+
+       jffs2_dbg(1, "%s(): ends...\n", __func__);
+
+       mutex_unlock(&c->alloc_sem);
+       return ret;
+}
+
+/* Pad write-buffer to end and write it, wasting space. */
+int jffs2_flush_wbuf_pad(struct jffs2_sb_info *c)
+{
+       int ret;
+
+       if (!c->wbuf)
+               return 0;
+
+       down_write(&c->wbuf_sem);
+       ret = __jffs2_flush_wbuf(c, PAD_NOACCOUNT);
+       /* retry - maybe wbuf recover left some data in wbuf. */
+       if (ret)
+               ret = __jffs2_flush_wbuf(c, PAD_NOACCOUNT);
+       up_write(&c->wbuf_sem);
+
+       return ret;
+}
+
+static size_t jffs2_fill_wbuf(struct jffs2_sb_info *c, const uint8_t *buf,
+                             size_t len)
+{
+       if (len && !c->wbuf_len && (len >= c->wbuf_pagesize))
+               return 0;
+
+       if (len > (c->wbuf_pagesize - c->wbuf_len))
+               len = c->wbuf_pagesize - c->wbuf_len;
+       memcpy(c->wbuf + c->wbuf_len, buf, len);
+       c->wbuf_len += (uint32_t) len;
+       return len;
+}
+
+int jffs2_flash_writev(struct jffs2_sb_info *c, const struct kvec *invecs,
+                      unsigned long count, loff_t to, size_t *retlen,
+                      uint32_t ino)
+{
+       struct jffs2_eraseblock *jeb;
+       size_t wbuf_retlen, donelen = 0;
+       uint32_t outvec_to = to;
+       int ret, invec;
+
+       /* If not writebuffered flash, don't bother */
+       if (!jffs2_is_writebuffered(c))
+               return jffs2_flash_direct_writev(c, invecs, count, to, retlen);
+
+       down_write(&c->wbuf_sem);
+
+       /* If wbuf_ofs is not initialized, set it to target address */
+       if (c->wbuf_ofs == 0xFFFFFFFF) {
+               c->wbuf_ofs = PAGE_DIV(to);
+               c->wbuf_len = PAGE_MOD(to);
+               memset(c->wbuf,0xff,c->wbuf_pagesize);
+       }
+
+       /*
+        * Sanity checks on target address.  It's permitted to write
+        * at PAD(c->wbuf_len+c->wbuf_ofs), and it's permitted to
+        * write at the beginning of a new erase block. Anything else,
+        * and you die.  New block starts at xxx000c (0-b = block
+        * header)
+        */
+       if (SECTOR_ADDR(to) != SECTOR_ADDR(c->wbuf_ofs)) {
+               /* It's a write to a new block */
+               if (c->wbuf_len) {
+                       jffs2_dbg(1, "%s(): to 0x%lx causes flush of wbuf at 0x%08x\n",
+                                 __func__, (unsigned long)to, c->wbuf_ofs);
+                       ret = __jffs2_flush_wbuf(c, PAD_NOACCOUNT);
+                       if (ret)
+                               goto outerr;
+               }
+               /* set pointer to new block */
+               c->wbuf_ofs = PAGE_DIV(to);
+               c->wbuf_len = PAGE_MOD(to);
+       }
+
+       if (to != PAD(c->wbuf_ofs + c->wbuf_len)) {
+               /* We're not writing immediately after the writebuffer. Bad. */
+               pr_crit("%s(): Non-contiguous write to %08lx\n",
+                       __func__, (unsigned long)to);
+               if (c->wbuf_len)
+                       pr_crit("wbuf was previously %08x-%08x\n",
+                               c->wbuf_ofs, c->wbuf_ofs + c->wbuf_len);
+               BUG();
+       }
+
+       /* adjust alignment offset */
+       if (c->wbuf_len != PAGE_MOD(to)) {
+               c->wbuf_len = PAGE_MOD(to);
+               /* take care of alignment to next page */
+               if (!c->wbuf_len) {
+                       c->wbuf_len = c->wbuf_pagesize;
+                       ret = __jffs2_flush_wbuf(c, NOPAD);
+                       if (ret)
+                               goto outerr;
+               }
+       }
+
+       for (invec = 0; invec < count; invec++) {
+               int vlen = invecs[invec].iov_len;
+               uint8_t *v = invecs[invec].iov_base;
+
+               wbuf_retlen = jffs2_fill_wbuf(c, v, vlen);
+
+               if (c->wbuf_len == c->wbuf_pagesize) {
+                       ret = __jffs2_flush_wbuf(c, NOPAD);
+                       if (ret)
+                               goto outerr;
+               }
+               vlen -= wbuf_retlen;
+               outvec_to += wbuf_retlen;
+               donelen += wbuf_retlen;
+               v += wbuf_retlen;
+
+               if (vlen >= c->wbuf_pagesize) {
+                       ret = mtd_write(c->mtd, outvec_to, PAGE_DIV(vlen),
+                                       &wbuf_retlen, v);
+                       if (ret < 0 || wbuf_retlen != PAGE_DIV(vlen))
+                               goto outfile;
+
+                       vlen -= wbuf_retlen;
+                       outvec_to += wbuf_retlen;
+                       c->wbuf_ofs = outvec_to;
+                       donelen += wbuf_retlen;
+                       v += wbuf_retlen;
+               }
+
+               wbuf_retlen = jffs2_fill_wbuf(c, v, vlen);
+               if (c->wbuf_len == c->wbuf_pagesize) {
+                       ret = __jffs2_flush_wbuf(c, NOPAD);
+                       if (ret)
+                               goto outerr;
+               }
+
+               outvec_to += wbuf_retlen;
+               donelen += wbuf_retlen;
+       }
+
+       /*
+        * If there's a remainder in the wbuf and it's a non-GC write,
+        * remember that the wbuf affects this ino
+        */
+       *retlen = donelen;
+
+       if (jffs2_sum_active()) {
+               int res = jffs2_sum_add_kvec(c, invecs, count, (uint32_t) to);
+               if (res)
+                       return res;
+       }
+
+       if (c->wbuf_len && ino)
+               jffs2_wbuf_dirties_inode(c, ino);
+
+       ret = 0;
+       up_write(&c->wbuf_sem);
+       return ret;
+
+outfile:
+       /*
+        * At this point we have no problem, c->wbuf is empty. However
+        * refile nextblock to avoid writing again to same address.
+        */
+
+       spin_lock(&c->erase_completion_lock);
+
+       jeb = &c->blocks[outvec_to / c->sector_size];
+       jffs2_block_refile(c, jeb, REFILE_ANYWAY);
+
+       spin_unlock(&c->erase_completion_lock);
+
+outerr:
+       *retlen = 0;
+       up_write(&c->wbuf_sem);
+       return ret;
+}
+
+/*
+ *     This is the entry for flash write.
+ *     Check, if we work on NAND FLASH, if so build an kvec and write it via vritev
+*/
+int jffs2_flash_write(struct jffs2_sb_info *c, loff_t ofs, size_t len,
+                     size_t *retlen, const u_char *buf)
+{
+       struct kvec vecs[1];
+
+       if (!jffs2_is_writebuffered(c))
+               return jffs2_flash_direct_write(c, ofs, len, retlen, buf);
+
+       vecs[0].iov_base = (unsigned char *) buf;
+       vecs[0].iov_len = len;
+       return jffs2_flash_writev(c, vecs, 1, ofs, retlen, 0);
+}
+
+/*
+       Handle readback from writebuffer and ECC failure return
+*/
+int jffs2_flash_read(struct jffs2_sb_info *c, loff_t ofs, size_t len, size_t *retlen, u_char *buf)
+{
+       loff_t  orbf = 0, owbf = 0, lwbf = 0;
+       int     ret;
+
+       if (!jffs2_is_writebuffered(c))
+               return mtd_read(c->mtd, ofs, len, retlen, buf);
+
+       /* Read flash */
+       down_read(&c->wbuf_sem);
+       ret = mtd_read(c->mtd, ofs, len, retlen, buf);
+
+       if ( (ret == -EBADMSG || ret == -EUCLEAN) && (*retlen == len) ) {
+               if (ret == -EBADMSG)
+                       pr_warn("mtd->read(0x%zx bytes from 0x%llx) returned ECC error\n",
+                               len, ofs);
+               /*
+                * We have the raw data without ECC correction in the buffer,
+                * maybe we are lucky and all data or parts are correct. We
+                * check the node.  If data are corrupted node check will sort
+                * it out.  We keep this block, it will fail on write or erase
+                * and the we mark it bad. Or should we do that now? But we
+                * should give him a chance.  Maybe we had a system crash or
+                * power loss before the ecc write or a erase was completed.
+                * So we return success. :)
+                */
+               ret = 0;
+       }
+
+       /* if no writebuffer available or write buffer empty, return */
+       if (!c->wbuf_pagesize || !c->wbuf_len)
+               goto exit;
+
+       /* if we read in a different block, return */
+       if (SECTOR_ADDR(ofs) != SECTOR_ADDR(c->wbuf_ofs))
+               goto exit;
+
+       if (ofs >= c->wbuf_ofs) {
+               owbf = (ofs - c->wbuf_ofs);     /* offset in write buffer */
+               if (owbf > c->wbuf_len)         /* is read beyond write buffer ? */
+                       goto exit;
+               lwbf = c->wbuf_len - owbf;      /* number of bytes to copy */
+               if (lwbf > len)
+                       lwbf = len;
+       } else {
+               orbf = (c->wbuf_ofs - ofs);     /* offset in read buffer */
+               if (orbf > len)                 /* is write beyond write buffer ? */
+                       goto exit;
+               lwbf = len - orbf;              /* number of bytes to copy */
+               if (lwbf > c->wbuf_len)
+                       lwbf = c->wbuf_len;
+       }
+       if (lwbf > 0)
+               memcpy(buf+orbf,c->wbuf+owbf,lwbf);
+
+exit:
+       up_read(&c->wbuf_sem);
+       return ret;
+}
+
+#define NR_OOB_SCAN_PAGES 4
+
+/* For historical reasons we use only 8 bytes for OOB clean marker */
+#define OOB_CM_SIZE 8
+
+static const struct jffs2_unknown_node oob_cleanmarker =
+{
+       .magic = constant_cpu_to_je16(JFFS2_MAGIC_BITMASK),
+       .nodetype = constant_cpu_to_je16(JFFS2_NODETYPE_CLEANMARKER),
+       .totlen = constant_cpu_to_je32(8)
+};
+
+/*
+ * Check, if the out of band area is empty. This function knows about the clean
+ * marker and if it is present in OOB, treats the OOB as empty anyway.
+ */
+int jffs2_check_oob_empty(struct jffs2_sb_info *c,
+                         struct jffs2_eraseblock *jeb, int mode)
+{
+       int i, ret;
+       int cmlen = min_t(int, c->oobavail, OOB_CM_SIZE);
+       struct mtd_oob_ops ops;
+
+       ops.mode = MTD_OPS_AUTO_OOB;
+       ops.ooblen = NR_OOB_SCAN_PAGES * c->oobavail;
+       ops.oobbuf = c->oobbuf;
+       ops.len = ops.ooboffs = ops.retlen = ops.oobretlen = 0;
+       ops.datbuf = NULL;
+
+       ret = mtd_read_oob(c->mtd, jeb->offset, &ops);
+       if ((ret && !mtd_is_bitflip(ret)) || ops.oobretlen != ops.ooblen) {
+               pr_err("cannot read OOB for EB at %08x, requested %zd bytes, read %zd bytes, error %d\n",
+                      jeb->offset, ops.ooblen, ops.oobretlen, ret);
+               if (!ret || mtd_is_bitflip(ret))
+                       ret = -EIO;
+               return ret;
+       }
+
+       for(i = 0; i < ops.ooblen; i++) {
+               if (mode && i < cmlen)
+                       /* Yeah, we know about the cleanmarker */
+                       continue;
+
+               if (ops.oobbuf[i] != 0xFF) {
+                       jffs2_dbg(2, "Found %02x at %x in OOB for "
+                                 "%08x\n", ops.oobbuf[i], i, jeb->offset);
+                       return 1;
+               }
+       }
+
+       return 0;
+}
+
+/*
+ * Check for a valid cleanmarker.
+ * Returns: 0 if a valid cleanmarker was found
+ *         1 if no cleanmarker was found
+ *         negative error code if an error occurred
+ */
+int jffs2_check_nand_cleanmarker(struct jffs2_sb_info *c,
+                                struct jffs2_eraseblock *jeb)
+{
+       struct mtd_oob_ops ops;
+       int ret, cmlen = min_t(int, c->oobavail, OOB_CM_SIZE);
+
+       ops.mode = MTD_OPS_AUTO_OOB;
+       ops.ooblen = cmlen;
+       ops.oobbuf = c->oobbuf;
+       ops.len = ops.ooboffs = ops.retlen = ops.oobretlen = 0;
+       ops.datbuf = NULL;
+
+       ret = mtd_read_oob(c->mtd, jeb->offset, &ops);
+       if ((ret && !mtd_is_bitflip(ret)) || ops.oobretlen != ops.ooblen) {
+               pr_err("cannot read OOB for EB at %08x, requested %zd bytes, read %zd bytes, error %d\n",
+                      jeb->offset, ops.ooblen, ops.oobretlen, ret);
+               if (!ret || mtd_is_bitflip(ret))
+                       ret = -EIO;
+               return ret;
+       }
+
+       return !!memcmp(&oob_cleanmarker, c->oobbuf, cmlen);
+}
+
+int jffs2_write_nand_cleanmarker(struct jffs2_sb_info *c,
+                                struct jffs2_eraseblock *jeb)
+{
+       int ret;
+       struct mtd_oob_ops ops;
+       int cmlen = min_t(int, c->oobavail, OOB_CM_SIZE);
+
+       ops.mode = MTD_OPS_AUTO_OOB;
+       ops.ooblen = cmlen;
+       ops.oobbuf = (uint8_t *)&oob_cleanmarker;
+       ops.len = ops.ooboffs = ops.retlen = ops.oobretlen = 0;
+       ops.datbuf = NULL;
+
+       ret = mtd_write_oob(c->mtd, jeb->offset, &ops);
+       if (ret || ops.oobretlen != ops.ooblen) {
+               pr_err("cannot write OOB for EB at %08x, requested %zd bytes, read %zd bytes, error %d\n",
+                      jeb->offset, ops.ooblen, ops.oobretlen, ret);
+               if (!ret)
+                       ret = -EIO;
+               return ret;
+       }
+
+       return 0;
+}
+
+/*
+ * On NAND we try to mark this block bad. If the block was erased more
+ * than MAX_ERASE_FAILURES we mark it finally bad.
+ * Don't care about failures. This block remains on the erase-pending
+ * or badblock list as long as nobody manipulates the flash with
+ * a bootloader or something like that.
+ */
+
+int jffs2_write_nand_badblock(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb, uint32_t bad_offset)
+{
+       int     ret;
+
+       /* if the count is < max, we try to write the counter to the 2nd page oob area */
+       if( ++jeb->bad_count < MAX_ERASE_FAILURES)
+               return 0;
+
+       pr_warn("marking eraseblock at %08x as bad\n", bad_offset);
+       ret = mtd_block_markbad(c->mtd, bad_offset);
+
+       if (ret) {
+               jffs2_dbg(1, "%s(): Write failed for block at %08x: error %d\n",
+                         __func__, jeb->offset, ret);
+               return ret;
+       }
+       return 1;
+}
+
+static struct jffs2_sb_info *work_to_sb(struct work_struct *work)
+{
+       struct delayed_work *dwork;
+
+       dwork = container_of(work, struct delayed_work, work);
+       return container_of(dwork, struct jffs2_sb_info, wbuf_dwork);
+}
+
+static void delayed_wbuf_sync(struct work_struct *work)
+{
+       struct jffs2_sb_info *c = work_to_sb(work);
+       struct super_block *sb = OFNI_BS_2SFFJ(c);
+
+       if (!(sb->s_flags & MS_RDONLY)) {
+               jffs2_dbg(1, "%s()\n", __func__);
+               jffs2_flush_wbuf_gc(c, 0);
+       }
+}
+
+void jffs2_dirty_trigger(struct jffs2_sb_info *c)
+{
+       struct super_block *sb = OFNI_BS_2SFFJ(c);
+       unsigned long delay;
+
+       if (sb->s_flags & MS_RDONLY)
+               return;
+
+       delay = msecs_to_jiffies(dirty_writeback_interval * 10);
+       if (queue_delayed_work(system_long_wq, &c->wbuf_dwork, delay))
+               jffs2_dbg(1, "%s()\n", __func__);
+}
+
+int jffs2_nand_flash_setup(struct jffs2_sb_info *c)
+{
+       struct nand_ecclayout *oinfo = c->mtd->ecclayout;
+
+       if (!c->mtd->oobsize)
+               return 0;
+
+       /* Cleanmarker is out-of-band, so inline size zero */
+       c->cleanmarker_size = 0;
+
+       if (!oinfo || oinfo->oobavail == 0) {
+               pr_err("inconsistent device description\n");
+               return -EINVAL;
+       }
+
+       jffs2_dbg(1, "using OOB on NAND\n");
+
+       c->oobavail = oinfo->oobavail;
+
+       /* Initialise write buffer */
+       init_rwsem(&c->wbuf_sem);
+       INIT_DELAYED_WORK(&c->wbuf_dwork, delayed_wbuf_sync);
+       c->wbuf_pagesize = c->mtd->writesize;
+       c->wbuf_ofs = 0xFFFFFFFF;
+
+       c->wbuf = kmalloc(c->wbuf_pagesize, GFP_KERNEL);
+       if (!c->wbuf)
+               return -ENOMEM;
+
+       c->oobbuf = kmalloc(NR_OOB_SCAN_PAGES * c->oobavail, GFP_KERNEL);
+       if (!c->oobbuf) {
+               kfree(c->wbuf);
+               return -ENOMEM;
+       }
+
+#ifdef CONFIG_JFFS2_FS_WBUF_VERIFY
+       c->wbuf_verify = kmalloc(c->wbuf_pagesize, GFP_KERNEL);
+       if (!c->wbuf_verify) {
+               kfree(c->oobbuf);
+               kfree(c->wbuf);
+               return -ENOMEM;
+       }
+#endif
+       return 0;
+}
+
+void jffs2_nand_flash_cleanup(struct jffs2_sb_info *c)
+{
+#ifdef CONFIG_JFFS2_FS_WBUF_VERIFY
+       kfree(c->wbuf_verify);
+#endif
+       kfree(c->wbuf);
+       kfree(c->oobbuf);
+}
+
+int jffs2_dataflash_setup(struct jffs2_sb_info *c) {
+       c->cleanmarker_size = 0;                /* No cleanmarkers needed */
+
+       /* Initialize write buffer */
+       init_rwsem(&c->wbuf_sem);
+       INIT_DELAYED_WORK(&c->wbuf_dwork, delayed_wbuf_sync);
+       c->wbuf_pagesize =  c->mtd->erasesize;
+
+       /* Find a suitable c->sector_size
+        * - Not too much sectors
+        * - Sectors have to be at least 4 K + some bytes
+        * - All known dataflashes have erase sizes of 528 or 1056
+        * - we take at least 8 eraseblocks and want to have at least 8K size
+        * - The concatenation should be a power of 2
+       */
+
+       c->sector_size = 8 * c->mtd->erasesize;
+
+       while (c->sector_size < 8192) {
+               c->sector_size *= 2;
+       }
+
+       /* It may be necessary to adjust the flash size */
+       c->flash_size = c->mtd->size;
+
+       if ((c->flash_size % c->sector_size) != 0) {
+               c->flash_size = (c->flash_size / c->sector_size) * c->sector_size;
+               pr_warn("flash size adjusted to %dKiB\n", c->flash_size);
+       };
+
+       c->wbuf_ofs = 0xFFFFFFFF;
+       c->wbuf = kmalloc(c->wbuf_pagesize, GFP_KERNEL);
+       if (!c->wbuf)
+               return -ENOMEM;
+
+#ifdef CONFIG_JFFS2_FS_WBUF_VERIFY
+       c->wbuf_verify = kmalloc(c->wbuf_pagesize, GFP_KERNEL);
+       if (!c->wbuf_verify) {
+               kfree(c->oobbuf);
+               kfree(c->wbuf);
+               return -ENOMEM;
+       }
+#endif
+
+       pr_info("write-buffering enabled buffer (%d) erasesize (%d)\n",
+               c->wbuf_pagesize, c->sector_size);
+
+       return 0;
+}
+
+void jffs2_dataflash_cleanup(struct jffs2_sb_info *c) {
+#ifdef CONFIG_JFFS2_FS_WBUF_VERIFY
+       kfree(c->wbuf_verify);
+#endif
+       kfree(c->wbuf);
+}
+
+int jffs2_nor_wbuf_flash_setup(struct jffs2_sb_info *c) {
+       /* Cleanmarker currently occupies whole programming regions,
+        * either one or 2 for 8Byte STMicro flashes. */
+       c->cleanmarker_size = max(16u, c->mtd->writesize);
+
+       /* Initialize write buffer */
+       init_rwsem(&c->wbuf_sem);
+       INIT_DELAYED_WORK(&c->wbuf_dwork, delayed_wbuf_sync);
+
+       c->wbuf_pagesize = c->mtd->writesize;
+       c->wbuf_ofs = 0xFFFFFFFF;
+
+       c->wbuf = kmalloc(c->wbuf_pagesize, GFP_KERNEL);
+       if (!c->wbuf)
+               return -ENOMEM;
+
+#ifdef CONFIG_JFFS2_FS_WBUF_VERIFY
+       c->wbuf_verify = kmalloc(c->wbuf_pagesize, GFP_KERNEL);
+       if (!c->wbuf_verify) {
+               kfree(c->wbuf);
+               return -ENOMEM;
+       }
+#endif
+       return 0;
+}
+
+void jffs2_nor_wbuf_flash_cleanup(struct jffs2_sb_info *c) {
+#ifdef CONFIG_JFFS2_FS_WBUF_VERIFY
+       kfree(c->wbuf_verify);
+#endif
+       kfree(c->wbuf);
+}
+
+int jffs2_ubivol_setup(struct jffs2_sb_info *c) {
+       c->cleanmarker_size = 0;
+
+       if (c->mtd->writesize == 1)
+               /* We do not need write-buffer */
+               return 0;
+
+       init_rwsem(&c->wbuf_sem);
+       INIT_DELAYED_WORK(&c->wbuf_dwork, delayed_wbuf_sync);
+
+       c->wbuf_pagesize =  c->mtd->writesize;
+       c->wbuf_ofs = 0xFFFFFFFF;
+       c->wbuf = kmalloc(c->wbuf_pagesize, GFP_KERNEL);
+       if (!c->wbuf)
+               return -ENOMEM;
+
+       pr_info("write-buffering enabled buffer (%d) erasesize (%d)\n",
+               c->wbuf_pagesize, c->sector_size);
+
+       return 0;
+}
+
+void jffs2_ubivol_cleanup(struct jffs2_sb_info *c) {
+       kfree(c->wbuf);
+}