Release 4.10 fs/jffs2/scan.c

/*
 * JFFS2 -- Journalling Flash File System, Version 2.
 *
 * Copyright © 2001-2007 Red Hat, Inc.
 *
 * Created by David Woodhouse <dwmw2@infradead.org>
 *
 * For licensing information, see the file 'LICENCE' in this directory.
 *
 */


#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/mtd/mtd.h>
#include <linux/pagemap.h>
#include <linux/crc32.h>
#include <linux/compiler.h>
#include "nodelist.h"
#include "summary.h"
#include "debug.h"


#define DEFAULT_EMPTY_SCAN_SIZE 256


#define noisy_printk(noise, fmt, ...)					\
do {                                                                    \
        if (*(noise)) {                                                 \
                pr_notice(fmt, ##__VA_ARGS__);                          \
                (*(noise))--;                                           \
                if (!(*(noise)))                                        \
                        pr_notice("Further such events for this erase block will not be printed\n"); \
        }                                                               \
} while (0)


static uint32_t pseudo_random;

static int jffs2_scan_eraseblock (struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
				  unsigned char *buf, uint32_t buf_size, struct jffs2_summary *s);

/* These helper functions _must_ increase ofs and also do the dirty/used space accounting.
 * Returning an error will abort the mount - bad checksums etc. should just mark the space
 * as dirty.
 */
static int jffs2_scan_inode_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
				 struct jffs2_raw_inode *ri, uint32_t ofs, struct jffs2_summary *s);
static int jffs2_scan_dirent_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
				 struct jffs2_raw_dirent *rd, uint32_t ofs, struct jffs2_summary *s);



static inline int min_free(struct jffs2_sb_info *c)
{
	uint32_t min = 2 * sizeof(struct jffs2_raw_inode);
#ifdef CONFIG_JFFS2_FS_WRITEBUFFER
	if (!jffs2_can_mark_obsolete(c) && min < c->wbuf_pagesize)
		return c->wbuf_pagesize;
#endif
	return min;

}

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static inline uint32_t EMPTY_SCAN_SIZE(uint32_t sector_size) {
	if (sector_size < DEFAULT_EMPTY_SCAN_SIZE)
		return sector_size;
	else
		return DEFAULT_EMPTY_SCAN_SIZE;
}

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static int file_dirty(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb)
{
	int ret;

	if ((ret = jffs2_prealloc_raw_node_refs(c, jeb, 1)))
		return ret;
	if ((ret = jffs2_scan_dirty_space(c, jeb, jeb->free_size)))
		return ret;
	/* Turned wasted size into dirty, since we apparently 
           think it's recoverable now. */
	jeb->dirty_size += jeb->wasted_size;
	c->dirty_size += jeb->wasted_size;
	c->wasted_size -= jeb->wasted_size;
	jeb->wasted_size = 0;
	if (VERYDIRTY(c, jeb->dirty_size)) {
		list_add(&jeb->list, &c->very_dirty_list);
	} else {
		list_add(&jeb->list, &c->dirty_list);
	}
	return 0;
}

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int jffs2_scan_medium(struct jffs2_sb_info *c)
{
	int i, ret;
	uint32_t empty_blocks = 0, bad_blocks = 0;
	unsigned char *flashbuf = NULL;
	uint32_t buf_size = 0;
	struct jffs2_summary *s = NULL; /* summary info collected by the scan process */
#ifndef __ECOS
	size_t pointlen, try_size;

	ret = mtd_point(c->mtd, 0, c->mtd->size, &pointlen,
			(void **)&flashbuf, NULL);
	if (!ret && pointlen < c->mtd->size) {
		/* Don't muck about if it won't let us point to the whole flash */
		jffs2_dbg(1, "MTD point returned len too short: 0x%zx\n",
			  pointlen);
		mtd_unpoint(c->mtd, 0, pointlen);
		flashbuf = NULL;
	}
	if (ret && ret != -EOPNOTSUPP)
		jffs2_dbg(1, "MTD point failed %d\n", ret);
#endif
	if (!flashbuf) {
		/* For NAND it's quicker to read a whole eraseblock at a time,
                   apparently */
		if (jffs2_cleanmarker_oob(c))
			try_size = c->sector_size;
		else
			try_size = PAGE_SIZE;

		jffs2_dbg(1, "Trying to allocate readbuf of %zu "
			  "bytes\n", try_size);

		flashbuf = mtd_kmalloc_up_to(c->mtd, &try_size);
		if (!flashbuf)
			return -ENOMEM;

		jffs2_dbg(1, "Allocated readbuf of %zu bytes\n",
			  try_size);

		buf_size = (uint32_t)try_size;
	}

	if (jffs2_sum_active()) {
		s = kzalloc(sizeof(struct jffs2_summary), GFP_KERNEL);
		if (!s) {
			JFFS2_WARNING("Can't allocate memory for summary\n");
			ret = -ENOMEM;
			goto out;
		}
	}

	for (i=0; i<c->nr_blocks; i++) {
		struct jffs2_eraseblock *jeb = &c->blocks[i];

		cond_resched();

		/* reset summary info for next eraseblock scan */
		jffs2_sum_reset_collected(s);

		ret = jffs2_scan_eraseblock(c, jeb, buf_size?flashbuf:(flashbuf+jeb->offset),
						buf_size, s);

		if (ret < 0)
			goto out;

		jffs2_dbg_acct_paranoia_check_nolock(c, jeb);

		/* Now decide which list to put it on */
		switch(ret) {
		case BLK_STATE_ALLFF:
			/*
                         * Empty block.   Since we can't be sure it
                         * was entirely erased, we just queue it for erase
                         * again.  It will be marked as such when the erase
                         * is complete.  Meanwhile we still count it as empty
                         * for later checks.
                         */
			empty_blocks++;
			list_add(&jeb->list, &c->erase_pending_list);
			c->nr_erasing_blocks++;
			break;

		case BLK_STATE_CLEANMARKER:
			/* Only a CLEANMARKER node is valid */
			if (!jeb->dirty_size) {
				/* It's actually free */
				list_add(&jeb->list, &c->free_list);
				c->nr_free_blocks++;
			} else {
				/* Dirt */
				jffs2_dbg(1, "Adding all-dirty block at 0x%08x to erase_pending_list\n",
					  jeb->offset);
				list_add(&jeb->list, &c->erase_pending_list);
				c->nr_erasing_blocks++;
			}
			break;

		case BLK_STATE_CLEAN:
			/* Full (or almost full) of clean data. Clean list */
			list_add(&jeb->list, &c->clean_list);
			break;

		case BLK_STATE_PARTDIRTY:
			/* Some data, but not full. Dirty list. */
			/* We want to remember the block with most free space
                        and stick it in the 'nextblock' position to start writing to it. */
			if (jeb->free_size > min_free(c) &&
					(!c->nextblock || c->nextblock->free_size < jeb->free_size)) {
				/* Better candidate for the next writes to go to */
				if (c->nextblock) {
					ret = file_dirty(c, c->nextblock);
					if (ret)
						goto out;
					/* deleting summary information of the old nextblock */
					jffs2_sum_reset_collected(c->summary);
				}
				/* update collected summary information for the current nextblock */
				jffs2_sum_move_collected(c, s);
				jffs2_dbg(1, "%s(): new nextblock = 0x%08x\n",
					  __func__, jeb->offset);
				c->nextblock = jeb;
			} else {
				ret = file_dirty(c, jeb);
				if (ret)
					goto out;
			}
			break;

		case BLK_STATE_ALLDIRTY:
			/* Nothing valid - not even a clean marker. Needs erasing. */
			/* For now we just put it on the erasing list. We'll start the erases later */
			jffs2_dbg(1, "Erase block at 0x%08x is not formatted. It will be erased\n",
				  jeb->offset);
			list_add(&jeb->list, &c->erase_pending_list);
			c->nr_erasing_blocks++;
			break;

		case BLK_STATE_BADBLOCK:
			jffs2_dbg(1, "Block at 0x%08x is bad\n", jeb->offset);
			list_add(&jeb->list, &c->bad_list);
			c->bad_size += c->sector_size;
			c->free_size -= c->sector_size;
			bad_blocks++;
			break;
		default:
			pr_warn("%s(): unknown block state\n", __func__);
			BUG();
		}
	}

	/* Nextblock dirty is always seen as wasted, because we cannot recycle it now */
	if (c->nextblock && (c->nextblock->dirty_size)) {
		c->nextblock->wasted_size += c->nextblock->dirty_size;
		c->wasted_size += c->nextblock->dirty_size;
		c->dirty_size -= c->nextblock->dirty_size;
		c->nextblock->dirty_size = 0;
	}
#ifdef CONFIG_JFFS2_FS_WRITEBUFFER
	if (!jffs2_can_mark_obsolete(c) && c->wbuf_pagesize && c->nextblock && (c->nextblock->free_size % c->wbuf_pagesize)) {
		/* If we're going to start writing into a block which already
                   contains data, and the end of the data isn't page-aligned,
                   skip a little and align it. */

		uint32_t skip = c->nextblock->free_size % c->wbuf_pagesize;

		jffs2_dbg(1, "%s(): Skipping %d bytes in nextblock to ensure page alignment\n",
			  __func__, skip);
		jffs2_prealloc_raw_node_refs(c, c->nextblock, 1);
		jffs2_scan_dirty_space(c, c->nextblock, skip);
	}
#endif
	if (c->nr_erasing_blocks) {
		if ( !c->used_size && ((c->nr_free_blocks+empty_blocks+bad_blocks)!= c->nr_blocks || bad_blocks == c->nr_blocks) ) {
			pr_notice("Cowardly refusing to erase blocks on filesystem with no valid JFFS2 nodes\n");
			pr_notice("empty_blocks %d, bad_blocks %d, c->nr_blocks %d\n",
				  empty_blocks, bad_blocks, c->nr_blocks);
			ret = -EIO;
			goto out;
		}
		spin_lock(&c->erase_completion_lock);
		jffs2_garbage_collect_trigger(c);
		spin_unlock(&c->erase_completion_lock);
	}
	ret = 0;
 out:
	if (buf_size)
		kfree(flashbuf);
#ifndef __ECOS
	else
		mtd_unpoint(c->mtd, 0, c->mtd->size);
#endif
	kfree(s);
	return ret;
}

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static int jffs2_fill_scan_buf(struct jffs2_sb_info *c, void *buf,
			       uint32_t ofs, uint32_t len)
{
	int ret;
	size_t retlen;

	ret = jffs2_flash_read(c, ofs, len, &retlen, buf);
	if (ret) {
		jffs2_dbg(1, "mtd->read(0x%x bytes from 0x%x) returned %d\n",
			  len, ofs, ret);
		return ret;
	}
	if (retlen < len) {
		jffs2_dbg(1, "Read at 0x%x gave only 0x%zx bytes\n",
			  ofs, retlen);
		return -EIO;
	}
	return 0;
}

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int jffs2_scan_classify_jeb(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb)
{
	if ((jeb->used_size + jeb->unchecked_size) == PAD(c->cleanmarker_size) && !jeb->dirty_size
	    && (!jeb->first_node || !ref_next(jeb->first_node)) )
		return BLK_STATE_CLEANMARKER;

	/* move blocks with max 4 byte dirty space to cleanlist */
	else if (!ISDIRTY(c->sector_size - (jeb->used_size + jeb->unchecked_size))) {
		c->dirty_size -= jeb->dirty_size;
		c->wasted_size += jeb->dirty_size;
		jeb->wasted_size += jeb->dirty_size;
		jeb->dirty_size = 0;
		return BLK_STATE_CLEAN;
	} else if (jeb->used_size || jeb->unchecked_size)
		return BLK_STATE_PARTDIRTY;
	else
		return BLK_STATE_ALLDIRTY;
}

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#ifdef CONFIG_JFFS2_FS_XATTR


static int jffs2_scan_xattr_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
				 struct jffs2_raw_xattr *rx, uint32_t ofs,
				 struct jffs2_summary *s)
{
	struct jffs2_xattr_datum *xd;
	uint32_t xid, version, totlen, crc;
	int err;

	crc = crc32(0, rx, sizeof(struct jffs2_raw_xattr) - 4);
	if (crc != je32_to_cpu(rx->node_crc)) {
		JFFS2_WARNING("node CRC failed at %#08x, read=%#08x, calc=%#08x\n",
			      ofs, je32_to_cpu(rx->node_crc), crc);
		if ((err = jffs2_scan_dirty_space(c, jeb, je32_to_cpu(rx->totlen))))
			return err;
		return 0;
	}

	xid = je32_to_cpu(rx->xid);
	version = je32_to_cpu(rx->version);

	totlen = PAD(sizeof(struct jffs2_raw_xattr)
			+ rx->name_len + 1 + je16_to_cpu(rx->value_len));
	if (totlen != je32_to_cpu(rx->totlen)) {
		JFFS2_WARNING("node length mismatch at %#08x, read=%u, calc=%u\n",
			      ofs, je32_to_cpu(rx->totlen), totlen);
		if ((err = jffs2_scan_dirty_space(c, jeb, je32_to_cpu(rx->totlen))))
			return err;
		return 0;
	}

	xd = jffs2_setup_xattr_datum(c, xid, version);
	if (IS_ERR(xd))
		return PTR_ERR(xd);

	if (xd->version > version) {
		struct jffs2_raw_node_ref *raw
			= jffs2_link_node_ref(c, jeb, ofs | REF_PRISTINE, totlen, NULL);
		raw->next_in_ino = xd->node->next_in_ino;
		xd->node->next_in_ino = raw;
	} else {
		xd->version = version;
		xd->xprefix = rx->xprefix;
		xd->name_len = rx->name_len;
		xd->value_len = je16_to_cpu(rx->value_len);
		xd->data_crc = je32_to_cpu(rx->data_crc);

		jffs2_link_node_ref(c, jeb, ofs | REF_PRISTINE, totlen, (void *)xd);
	}

	if (jffs2_sum_active())
		jffs2_sum_add_xattr_mem(s, rx, ofs - jeb->offset);
	dbg_xattr("scanning xdatum at %#08x (xid=%u, version=%u)\n",
		  ofs, xd->xid, xd->version);
	return 0;
}

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static int jffs2_scan_xref_node(struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
				struct jffs2_raw_xref *rr, uint32_t ofs,
				struct jffs2_summary *s)
{
	struct jffs2_xattr_ref *ref;
	uint32_t crc;
	int err;

	crc = crc32(0, rr, sizeof(*rr) - 4);
	if (crc != je32_to_cpu(rr->node_crc)) {
		JFFS2_WARNING("node CRC failed at %#08x, read=%#08x, calc=%#08x\n",
			      ofs, je32_to_cpu(rr->node_crc), crc);
		if ((err = jffs2_scan_dirty_space(c, jeb, PAD(je32_to_cpu(rr->totlen)))))
			return err;
		return 0;
	}

	if (PAD(sizeof(struct jffs2_raw_xref)) != je32_to_cpu(rr->totlen)) {
		JFFS2_WARNING("node length mismatch at %#08x, read=%u, calc=%zd\n",
			      ofs, je32_to_cpu(rr->totlen),
			      PAD(sizeof(struct jffs2_raw_xref)));
		if ((err = jffs2_scan_dirty_space(c, jeb, je32_to_cpu(rr->totlen))))
			return err;
		return 0;
	}

	ref = jffs2_alloc_xattr_ref();
	if (!ref)
		return -ENOMEM;

	/* BEFORE jffs2_build_xattr_subsystem() called, 
         * and AFTER xattr_ref is marked as a dead xref,
         * ref->xid is used to store 32bit xid, xd is not used
         * ref->ino is used to store 32bit inode-number, ic is not used
         * Thoes variables are declared as union, thus using those
         * are exclusive. In a similar way, ref->next is temporarily
         * used to chain all xattr_ref object. It's re-chained to
         * jffs2_inode_cache in jffs2_build_xattr_subsystem() correctly.
         */
	ref->ino = je32_to_cpu(rr->ino);
	ref->xid = je32_to_cpu(rr->xid);
	ref->xseqno = je32_to_cpu(rr->xseqno);
	if (ref->xseqno > c->highest_xseqno)
		c->highest_xseqno = (ref->xseqno & ~XREF_DELETE_MARKER);
	ref->next = c->xref_temp;
	c->xref_temp = ref;

	jffs2_link_node_ref(c, jeb, ofs | REF_PRISTINE, PAD(je32_to_cpu(rr->totlen)), (void *)ref);

	if (jffs2_sum_active())
		jffs2_sum_add_xref_mem(s, rr, ofs - jeb->offset);
	dbg_xattr("scan xref at %#08x (xid=%u, ino=%u)\n",
		  ofs, ref->xid, ref->ino);
	return 0;
}
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#endif

/* Called with 'buf_size == 0' if buf is in fact a pointer _directly_ into
   the flash, XIP-style */


static int jffs2_scan_eraseblock (struct jffs2_sb_info *c, struct jffs2_eraseblock *jeb,
				  unsigned char *buf, uint32_t buf_size, struct jffs2_summary *s) {
	struct jffs2_unknown_node *node;
	struct jffs2_unknown_node crcnode;
	uint32_t ofs, prevofs, max_ofs;
	uint32_t hdr_crc, buf_ofs, buf_len;
	int err;
	int noise = 0;


#ifdef CONFIG_JFFS2_FS_WRITEBUFFER
	int cleanmarkerfound = 0;
#endif

	ofs = jeb->offset;
	prevofs = jeb->offset - 1;

	jffs2_dbg(1, "%s(): Scanning block at 0x%x\n", __func__, ofs);

#ifdef CONFIG_JFFS2_FS_WRITEBUFFER
	if (jffs2_cleanmarker_oob(c)) {
		int ret;

		if (mtd_block_isbad(c->mtd, jeb->offset))
			return BLK_STATE_BADBLOCK;

		ret = jffs2_check_nand_cleanmarker(c, jeb);
		jffs2_dbg(2, "jffs_check_nand_cleanmarker returned %d\n", ret);

		/* Even if it's not found, we still scan to see
                   if the block is empty. We use this information
                   to decide whether to erase it or not. */
		switch (ret) {
		case 0:		cleanmarkerfound = 1; break;
		case 1: 	break;
		default: 	return ret;
		}
	}
#endif

	if (jffs2_sum_active()) {
		struct jffs2_sum_marker *sm;
		void *sumptr = NULL;
		uint32_t sumlen;
	      
		if (!buf_size) {
			/* XIP case. Just look, point at the summary if it's there */
			sm = (void *)buf + c->sector_size - sizeof(*sm);
			if (je32_to_cpu(sm->magic) == JFFS2_SUM_MAGIC) {
				sumptr = buf + je32_to_cpu(sm->offset);
				sumlen = c->sector_size - je32_to_cpu(sm->offset);
			}
		} else {
			/* If NAND flash, read a whole page of it. Else just the end */
			if (c->wbuf_pagesize)
				buf_len = c->wbuf_pagesize;
			else
				buf_len = sizeof(*sm);

			/* Read as much as we want into the _end_ of the preallocated buffer */
			err = jffs2_fill_scan_buf(c, buf + buf_size - buf_len, 
						  jeb->offset + c->sector_size - buf_len,
						  buf_len);				
			if (err)
				return err;

			sm = (void *)buf + buf_size - sizeof(*sm);
			if (je32_to_cpu(sm->magic) == JFFS2_SUM_MAGIC) {
				sumlen = c->sector_size - je32_to_cpu(sm->offset);
				sumptr = buf + buf_size - sumlen;

				/* sm->offset maybe wrong but MAGIC maybe right */
				if (sumlen > c->sector_size)
					goto full_scan;

				/* Now, make sure the summary itself is available */
				if (sumlen > buf_size) {
					/* Need to kmalloc for this. */
					sumptr = kmalloc(sumlen, GFP_KERNEL);
					if (!sumptr)
						return -ENOMEM;
					memcpy(sumptr + sumlen - buf_len, buf + buf_size - buf_len, buf_len);
				}
				if (buf_len < sumlen) {
					/* Need to read more so that the entire summary node is present */
					err = jffs2_fill_scan_buf(c, sumptr, 
								  jeb->offset + c->sector_size - sumlen,
								  sumlen - buf_len);				
					if (err)
						return err;
				}
			}

		}

		if (sumptr) {
			err = jffs2_sum_scan_sumnode(c, jeb, sumptr, sumlen, &pseudo_random);

			if (buf_size && sumlen > buf_size)
				kfree(sumptr);
			/* If it returns with a real error, bail. 
                           If it returns positive, that's a block classification
                           (i.e. BLK_STATE_xxx) so return that too.
                           If it returns zero, fall through to full scan. */
			if (err)
				return err;
		}
	}

full_scan:
	buf_ofs = jeb->offset;

	if (!buf_size) {
		/* This is the XIP case -- we're reading _directly_ from the flash chip */
		buf_len = c->sector_size;
	} else {
		buf_len = EMPTY_SCAN_SIZE(c->sector_size);
		err = jffs2_fill_scan_buf(c, buf, buf_ofs, buf_len);
		if (err)
			return err;
	}

	/* We temporarily use 'ofs' as a pointer into the buffer/jeb */
	ofs = 0;
	max_ofs = EMPTY_SCAN_SIZE(c->sector_size);
	/* Scan only EMPTY_SCAN_SIZE of 0xFF before declaring it's empty */
	while(ofs < max_ofs && *(uint32_t *)(&buf[ofs]) == 0xFFFFFFFF)
		ofs += 4;

	if (ofs == max_ofs) {
#ifdef CONFIG_JFFS2_FS_WRITEBUFFER
		if (jffs2_cleanmarker_oob(c)) {
			/* scan oob, take care of cleanmarker */
			int ret = jffs2_check_oob_empty(c, jeb, cleanmarkerfound);
			jffs2_dbg(2, "jffs2_check_oob_empty returned %d\n",
				  ret);
			switch (ret) {
			case 0:		return cleanmarkerfound ? BLK_STATE_CLEANMARKER : BLK_STATE_ALLFF;
			case 1: 	return BLK_STATE_ALLDIRTY;
			default: 	return ret;
			}
		}
#endif
		jffs2_dbg(1, "Block at 0x%08x is empty (erased)\n",
			  jeb->offset);
		if (c->cleanmarker_size == 0)
			return BLK_STATE_CLEANMARKER;	/* don't bother with re-erase */
		else
			return BLK_STATE_ALLFF;	/* OK to erase if all blocks are like this */
	}
	if (ofs) {
		jffs2_dbg(1, "Free space at %08x ends at %08x\n", jeb->offset,
			  jeb->offset + ofs);
		if ((err = jffs2_prealloc_raw_node_refs(c, jeb,