Merge branch 'linux-next' of git://git.infradead.org/ubifs-2.6

			of this option is that corruption of the contents

			of a file can go unnoticed.

chk_data_crc (*)	do not skip checking CRCs on data nodes

compr=none              override default compressor and set it to "none"

compr=lzo               override default compressor and set it to "lzo"

compr=zlib              override default compressor and set it to "zlib"

Quick usage instructions

#include "ubifs.h"

#include <linux/writeback.h>

#include <asm/div64.h>

#include <linux/math64.h>

/*

 * When pessimistic budget calculations say that there is no enough space,

 * UBIFS starts writing back dirty inodes and pages, doing garbage collection,

 * or committing. The below constants define maximum number of times UBIFS

 * or committing. The below constant defines maximum number of times UBIFS

 * repeats the operations.

 */

#define MAX_SHRINK_RETRIES 8

#define MAX_GC_RETRIES     4

#define MAX_CMT_RETRIES    2

#define MAX_NOSPC_RETRIES  1

#define MAX_MKSPC_RETRIES 3

/*

 * The below constant defines amount of dirty pages which should be written

 */

#define NR_TO_WRITE 16

/**

 * struct retries_info - information about re-tries while making free space.

 * @prev_liability: previous liability

 * @shrink_cnt: how many times the liability was shrinked

 * @shrink_retries: count of liability shrink re-tries (increased when

 *                  liability does not shrink)

 * @try_gc: GC should be tried first

 * @gc_retries: how many times GC was run

 * @cmt_retries: how many times commit has been done

 * @nospc_retries: how many times GC returned %-ENOSPC

 *

 * Since we consider budgeting to be the fast-path, and this structure has to

 * be allocated on stack and zeroed out, we make it smaller using bit-fields.

 */

struct retries_info {

	long long prev_liability;

	unsigned int shrink_cnt;

	unsigned int shrink_retries:5;

	unsigned int try_gc:1;

	unsigned int gc_retries:4;

	unsigned int cmt_retries:3;

	unsigned int nospc_retries:1;

};

/**

 * shrink_liability - write-back some dirty pages/inodes.

 * @c: UBIFS file-system description object

	return 0;

}

/**

 * get_liability - calculate current liability.

 * @c: UBIFS file-system description object

 *

 * This function calculates and returns current UBIFS liability, i.e. the

 * amount of bytes UBIFS has "promised" to write to the media.

 */

static long long get_liability(struct ubifs_info *c)

{

	long long liab;

	spin_lock(&c->space_lock);

	liab = c->budg_idx_growth + c->budg_data_growth + c->budg_dd_growth;

	spin_unlock(&c->space_lock);

	return liab;

}

/**

 * make_free_space - make more free space on the file-system.

 * @c: UBIFS file-system description object

 * @ri: information about previous invocations of this function

 *

 * This function is called when an operation cannot be budgeted because there

 * is supposedly no free space. But in most cases there is some free space:

 * Returns %-ENOSPC if it couldn't do more free space, and other negative error

 * codes on failures.

 */

static int make_free_space(struct ubifs_info *c, struct retries_info *ri)

static int make_free_space(struct ubifs_info *c)

{

	int err;

	int err, retries = 0;

	long long liab1, liab2;

	do {

		liab1 = get_liability(c);

		/*

	 * If we have some dirty pages and inodes (liability), try to write

	 * them back unless this was tried too many times without effect

	 * already.

		 * We probably have some dirty pages or inodes (liability), try

		 * to write them back.

		 */

	if (ri->shrink_retries < MAX_SHRINK_RETRIES && !ri->try_gc) {

		long long liability;

		dbg_budg("liability %lld, run write-back", liab1);

		shrink_liability(c, NR_TO_WRITE);

		spin_lock(&c->space_lock);

		liability = c->budg_idx_growth + c->budg_data_growth +

			    c->budg_dd_growth;

		spin_unlock(&c->space_lock);

		if (ri->prev_liability >= liability) {

			/* Liability does not shrink, next time try GC then */

			ri->shrink_retries += 1;

			if (ri->gc_retries < MAX_GC_RETRIES)

				ri->try_gc = 1;

			dbg_budg("liability did not shrink: retries %d of %d",

				 ri->shrink_retries, MAX_SHRINK_RETRIES);

		}

		dbg_budg("force write-back (count %d)", ri->shrink_cnt);

		shrink_liability(c, NR_TO_WRITE + ri->shrink_cnt);

		ri->prev_liability = liability;

		ri->shrink_cnt += 1;

		liab2 = get_liability(c);

		if (liab2 < liab1)

			return -EAGAIN;

	}

	/*

	 * Try to run garbage collector unless it was already tried too many

	 * times.

	 */

	if (ri->gc_retries < MAX_GC_RETRIES) {

		ri->gc_retries += 1;

		dbg_budg("run GC, retries %d of %d",

			 ri->gc_retries, MAX_GC_RETRIES);

		dbg_budg("new liability %lld (not shrinked)", liab2);

		ri->try_gc = 0;

		/* Liability did not shrink again, try GC */

		dbg_budg("Run GC");

		err = run_gc(c);

		if (!err)

			return -EAGAIN;

		if (err == -EAGAIN) {

			dbg_budg("GC asked to commit");

			err = ubifs_run_commit(c);

			if (err)

				return err;

			return -EAGAIN;

		}

		if (err != -ENOSPC)

		if (err != -EAGAIN && err != -ENOSPC)

			/* Some real error happened */

			return err;

		/*

		 * GC could not make any progress. If this is the first time,

		 * then it makes sense to try to commit, because it might make

		 * some dirty space.

		 */

		dbg_budg("GC returned -ENOSPC, retries %d",

			 ri->nospc_retries);

		if (ri->nospc_retries >= MAX_NOSPC_RETRIES)

			return err;

		ri->nospc_retries += 1;

	}

	/* Neither GC nor write-back helped, try to commit */

	if (ri->cmt_retries < MAX_CMT_RETRIES) {

		ri->cmt_retries += 1;

		dbg_budg("run commit, retries %d of %d",

			 ri->cmt_retries, MAX_CMT_RETRIES);

		dbg_budg("Run commit (retries %d)", retries);

		err = ubifs_run_commit(c);

		if (err)

			return err;

		return -EAGAIN;

	}

	} while (retries++ < MAX_MKSPC_RETRIES);

	return -ENOSPC;

}

 */

int ubifs_calc_min_idx_lebs(struct ubifs_info *c)

{

	int ret;

	uint64_t idx_size;

	int idx_lebs, eff_leb_size = c->leb_size - c->max_idx_node_sz;

	long long idx_size;

	idx_size = c->old_idx_sz + c->budg_idx_growth + c->budg_uncommitted_idx;

	 * pair, nor similarly the two variables for the new index size, so we

	 * have to do this costly 64-bit division on fast-path.

	 */

	if (do_div(idx_size, c->leb_size - c->max_idx_node_sz))

		ret = idx_size + 1;

	else

		ret = idx_size;

	idx_size += eff_leb_size - 1;

	idx_lebs = div_u64(idx_size, eff_leb_size);

	/*

	 * The index head is not available for the in-the-gaps method, so add an

	 * extra LEB to compensate.

	 */

	ret += 1;

	/*

	 * At present the index needs at least 2 LEBs: one for the index head

	 * and one for in-the-gaps method (which currently does not cater for

	 * the index head and so excludes it from consideration).

	 */

	if (ret < 2)

		ret = 2;

	return ret;

	idx_lebs += 1;

	if (idx_lebs < MIN_INDEX_LEBS)

		idx_lebs = MIN_INDEX_LEBS;

	return idx_lebs;

}

/**

int ubifs_budget_space(struct ubifs_info *c, struct ubifs_budget_req *req)

{

	int uninitialized_var(cmt_retries), uninitialized_var(wb_retries);

	int err, idx_growth, data_growth, dd_growth;

	struct retries_info ri;

	int err, idx_growth, data_growth, dd_growth, retried = 0;

	ubifs_assert(req->new_page <= 1);

	ubifs_assert(req->dirtied_page <= 1);

	if (!data_growth && !dd_growth)

		return 0;

	idx_growth = calc_idx_growth(c, req);

	memset(&ri, 0, sizeof(struct retries_info));

again:

	spin_lock(&c->space_lock);

		return err;

	}

	err = make_free_space(c, &ri);

	err = make_free_space(c);

	cond_resched();

	if (err == -EAGAIN) {

		dbg_budg("try again");

		cond_resched();

		goto again;

	} else if (err == -ENOSPC) {

		if (!retried) {

			retried = 1;

			dbg_budg("-ENOSPC, but anyway try once again");

			goto again;

		}

		dbg_budg("FS is full, -ENOSPC");

		c->nospace = 1;

		if (can_use_rp(c) || c->rp_size == 0)

 * user-space. User-space application tend to expect that if the file-system

 * (e.g., via the 'statfs()' call) reports that it has N bytes available, they

 * are able to write a file of size N. UBIFS attaches node headers to each data

 * node and it has to write indexind nodes as well. This introduces additional

 * overhead, and UBIFS it has to report sligtly less free space to meet the

 * above expectetion.

 * node and it has to write indexing nodes as well. This introduces additional

 * overhead, and UBIFS has to report slightly less free space to meet the above

 * expectations.

 *

 * This function assumes free space is made up of uncompressed data nodes and

 * full index nodes (one per data node, tripled because we always allow enough

 * Note, the calculation is pessimistic, which means that most of the time

 * UBIFS reports less space than it actually has.

 */

long long ubifs_reported_space(const struct ubifs_info *c, uint64_t free)

long long ubifs_reported_space(const struct ubifs_info *c, long long free)

{

	int divisor, factor, f;

	 * of data nodes, f - fanout. Because effective UBIFS fanout is twice

	 * as less than maximum fanout, we assume that each data node

	 * introduces 3 * @c->max_idx_node_sz / (@c->fanout/2 - 1) bytes.

	 * Note, the multiplier 3 is because UBIFS reseves thrice as more space

	 * Note, the multiplier 3 is because UBIFS reserves thrice as more space

	 * for the index.

	 */

	f = c->fanout > 3 ? c->fanout >> 1 : 2;

	divisor = UBIFS_MAX_DATA_NODE_SZ;

	divisor += (c->max_idx_node_sz * 3) / (f - 1);

	free *= factor;

	do_div(free, divisor);

	return free;

	return div_u64(free, divisor);

}

/**

 * This function calculates amount of free space to report to user-space.

 *

 * Because UBIFS may introduce substantial overhead (the index, node headers,

 * alighment, wastage at the end of eraseblocks, etc), it cannot report real

 * alignment, wastage at the end of eraseblocks, etc), it cannot report real

 * amount of free flash space it has (well, because not all dirty space is

 * reclamable, UBIFS does not actually know the real amount). If UBIFS did so,

 * it would bread user expectetion about what free space is. Users seem to

 * reclaimable, UBIFS does not actually know the real amount). If UBIFS did so,

 * it would bread user expectations about what free space is. Users seem to

 * accustomed to assume that if the file-system reports N bytes of free space,

 * they would be able to fit a file of N bytes to the FS. This almost works for

 * traditional file-systems, because they have way less overhead than UBIFS.

	long long available, outstanding, free;

	spin_lock(&c->space_lock);

	min_idx_lebs = ubifs_calc_min_idx_lebs(c);

	min_idx_lebs = c->min_idx_lebs;

	ubifs_assert(min_idx_lebs == ubifs_calc_min_idx_lebs(c));

	outstanding = c->budg_data_growth + c->budg_dd_growth;

	/*

	 * Force the amount available to the total size reported if the used

	 * space is zero.

	 */

	if (c->lst.total_used <= UBIFS_INO_NODE_SZ && !outstanding) {

		spin_unlock(&c->space_lock);

		return (long long)c->block_cnt << UBIFS_BLOCK_SHIFT;

	}

	available = ubifs_calc_available(c, min_idx_lebs);

	/*

{

	struct ubifs_idx_node *idx;

	int lnum, offs, len, err = 0;

	struct ubifs_debug_info *d = c->dbg;

	c->old_zroot = *zroot;

	lnum = c->old_zroot.lnum;

	offs = c->old_zroot.offs;

	len = c->old_zroot.len;

	d->old_zroot = *zroot;

	lnum = d->old_zroot.lnum;

	offs = d->old_zroot.offs;

	len = d->old_zroot.len;

	idx = kmalloc(c->max_idx_node_sz, GFP_NOFS);

	if (!idx)

	if (err)

		goto out;

	c->old_zroot_level = le16_to_cpu(idx->level);

	c->old_zroot_sqnum = le64_to_cpu(idx->ch.sqnum);

	d->old_zroot_level = le16_to_cpu(idx->level);

	d->old_zroot_sqnum = le64_to_cpu(idx->ch.sqnum);

out:

	kfree(idx);

	return err;

{

	int lnum, offs, len, err = 0, uninitialized_var(last_level), child_cnt;

	int first = 1, iip;

	struct ubifs_debug_info *d = c->dbg;

	union ubifs_key lower_key, upper_key, l_key, u_key;

	unsigned long long uninitialized_var(last_sqnum);

	struct ubifs_idx_node *idx;

	     UBIFS_IDX_NODE_SZ;

	/* Start at the old zroot */

	lnum = c->old_zroot.lnum;

	offs = c->old_zroot.offs;

	len = c->old_zroot.len;

	lnum = d->old_zroot.lnum;

	offs = d->old_zroot.offs;

	len = d->old_zroot.len;

	iip = 0;

	/*

		if (first) {

			first = 0;

			/* Check root level and sqnum */

			if (le16_to_cpu(idx->level) != c->old_zroot_level) {

			if (le16_to_cpu(idx->level) != d->old_zroot_level) {

				err = 2;

				goto out_dump;

			}

			if (le64_to_cpu(idx->ch.sqnum) != c->old_zroot_sqnum) {

			if (le64_to_cpu(idx->ch.sqnum) != d->old_zroot_sqnum) {

				err = 3;

				goto out_dump;

			}

/* Fake description object for the "none" compressor */

static struct ubifs_compressor none_compr = {

	.compr_type = UBIFS_COMPR_NONE,

	.name = "no compression",

	.name = "none",

	.capi_name = "",

};

static struct ubifs_compressor lzo_compr = {

	.compr_type = UBIFS_COMPR_LZO,

	.comp_mutex = &lzo_mutex,

	.name = "LZO",

	.name = "lzo",

	.capi_name = "lzo",

};

#else

static struct ubifs_compressor lzo_compr = {

	.compr_type = UBIFS_COMPR_LZO,

	.name = "LZO",

	.name = "lzo",

};

#endif

	if (compr->comp_mutex)

		mutex_lock(compr->comp_mutex);

	err = crypto_comp_compress(compr->cc, in_buf, in_len, out_buf,

				   out_len);

				   (unsigned int *)out_len);

	if (compr->comp_mutex)

		mutex_unlock(compr->comp_mutex);

	if (unlikely(err)) {

	}

	/*

	 * Presently, we just require that compression results in less data,

	 * rather than any defined minimum compression ratio or amount.

	 * If the data compressed only slightly, it is better to leave it

	 * uncompressed to improve read speed.

	 */

	if (ALIGN(*out_len, 8) >= ALIGN(in_len, 8))

	if (in_len - *out_len < UBIFS_MIN_COMPRESS_DIFF)

		goto no_compr;

	return;

	if (compr->decomp_mutex)

		mutex_lock(compr->decomp_mutex);

	err = crypto_comp_decompress(compr->cc, in_buf, in_len, out_buf,

				     out_len);

				     (unsigned int *)out_len);

	if (compr->decomp_mutex)

		mutex_unlock(compr->decomp_mutex);

	if (err)

/**

 * ubifs_compressors_exit - de-initialize UBIFS compressors.

 */

void __exit ubifs_compressors_exit(void)

void ubifs_compressors_exit(void)

{

	compr_exit(&lzo_compr);

	compr_exit(&zlib_compr);