xfs_buf_item.c

linux 内核源代码

/*
 * Copyright (c) 2000-2005 Silicon Graphics, Inc.
 * All Rights Reserved.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it would be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write the Free Software Foundation,
 * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */
#include "xfs.h"
#include "xfs_fs.h"
#include "xfs_types.h"
#include "xfs_bit.h"
#include "xfs_log.h"
#include "xfs_inum.h"
#include "xfs_trans.h"
#include "xfs_sb.h"
#include "xfs_ag.h"
#include "xfs_dmapi.h"
#include "xfs_mount.h"
#include "xfs_buf_item.h"
#include "xfs_trans_priv.h"
#include "xfs_error.h"


kmem_zone_t	*xfs_buf_item_zone;

#ifdef XFS_TRANS_DEBUG
/*
 * This function uses an alternate strategy for tracking the bytes
 * that the user requests to be logged.  This can then be used
 * in conjunction with the bli_orig array in the buf log item to
 * catch bugs in our callers' code.
 *
 * We also double check the bits set in xfs_buf_item_log using a
 * simple algorithm to check that every byte is accounted for.
 */
STATIC void
xfs_buf_item_log_debug(
	xfs_buf_log_item_t	*bip,
	uint			first,
	uint			last)
{
	uint	x;
	uint	byte;
	uint	nbytes;
	uint	chunk_num;
	uint	word_num;
	uint	bit_num;
	uint	bit_set;
	uint	*wordp;

	ASSERT(bip->bli_logged != NULL);
	byte = first;
	nbytes = last - first + 1;
	bfset(bip->bli_logged, first, nbytes);
	for (x = 0; x < nbytes; x++) {
		chunk_num = byte >> XFS_BLI_SHIFT;
		word_num = chunk_num >> BIT_TO_WORD_SHIFT;
		bit_num = chunk_num & (NBWORD - 1);
		wordp = &(bip->bli_format.blf_data_map[word_num]);
		bit_set = *wordp & (1 << bit_num);
		ASSERT(bit_set);
		byte++;
	}
}

/*
 * This function is called when we flush something into a buffer without
 * logging it.  This happens for things like inodes which are logged
 * separately from the buffer.
 */
void
xfs_buf_item_flush_log_debug(
	xfs_buf_t	*bp,
	uint		first,
	uint		last)
{
	xfs_buf_log_item_t	*bip;
	uint			nbytes;

	bip = XFS_BUF_FSPRIVATE(bp, xfs_buf_log_item_t*);
	if ((bip == NULL) || (bip->bli_item.li_type != XFS_LI_BUF)) {
		return;
	}

	ASSERT(bip->bli_logged != NULL);
	nbytes = last - first + 1;
	bfset(bip->bli_logged, first, nbytes);
}

/*
 * This function is called to verify that our callers have logged
 * all the bytes that they changed.
 *
 * It does this by comparing the original copy of the buffer stored in
 * the buf log item's bli_orig array to the current copy of the buffer
 * and ensuring that all bytes which mismatch are set in the bli_logged
 * array of the buf log item.
 */
STATIC void
xfs_buf_item_log_check(
	xfs_buf_log_item_t	*bip)
{
	char		*orig;
	char		*buffer;
	int		x;
	xfs_buf_t	*bp;

	ASSERT(bip->bli_orig != NULL);
	ASSERT(bip->bli_logged != NULL);

	bp = bip->bli_buf;
	ASSERT(XFS_BUF_COUNT(bp) > 0);
	ASSERT(XFS_BUF_PTR(bp) != NULL);
	orig = bip->bli_orig;
	buffer = XFS_BUF_PTR(bp);
	for (x = 0; x < XFS_BUF_COUNT(bp); x++) {
		if (orig[x] != buffer[x] && !btst(bip->bli_logged, x))
			cmn_err(CE_PANIC,
	"xfs_buf_item_log_check bip %x buffer %x orig %x index %d",
				bip, bp, orig, x);
	}
}
#else
#define		xfs_buf_item_log_debug(x,y,z)
#define		xfs_buf_item_log_check(x)
#endif

STATIC void	xfs_buf_error_relse(xfs_buf_t *bp);
STATIC void	xfs_buf_do_callbacks(xfs_buf_t *bp, xfs_log_item_t *lip);

/*
 * This returns the number of log iovecs needed to log the
 * given buf log item.
 *
 * It calculates this as 1 iovec for the buf log format structure
 * and 1 for each stretch of non-contiguous chunks to be logged.
 * Contiguous chunks are logged in a single iovec.
 *
 * If the XFS_BLI_STALE flag has been set, then log nothing.
 */
STATIC uint
xfs_buf_item_size(
	xfs_buf_log_item_t	*bip)
{
	uint		nvecs;
	int		next_bit;
	int		last_bit;
	xfs_buf_t	*bp;

	ASSERT(atomic_read(&bip->bli_refcount) > 0);
	if (bip->bli_flags & XFS_BLI_STALE) {
		/*
		 * The buffer is stale, so all we need to log
		 * is the buf log format structure with the
		 * cancel flag in it.
		 */
		xfs_buf_item_trace("SIZE STALE", bip);
		ASSERT(bip->bli_format.blf_flags & XFS_BLI_CANCEL);
		return 1;
	}

	bp = bip->bli_buf;
	ASSERT(bip->bli_flags & XFS_BLI_LOGGED);
	nvecs = 1;
	last_bit = xfs_next_bit(bip->bli_format.blf_data_map,
					 bip->bli_format.blf_map_size, 0);
	ASSERT(last_bit != -1);
	nvecs++;
	while (last_bit != -1) {
		/*
		 * This takes the bit number to start looking from and
		 * returns the next set bit from there.  It returns -1
		 * if there are no more bits set or the start bit is
		 * beyond the end of the bitmap.
		 */
		next_bit = xfs_next_bit(bip->bli_format.blf_data_map,
						 bip->bli_format.blf_map_size,
						 last_bit + 1);
		/*
		 * If we run out of bits, leave the loop,
		 * else if we find a new set of bits bump the number of vecs,
		 * else keep scanning the current set of bits.
		 */
		if (next_bit == -1) {
			last_bit = -1;
		} else if (next_bit != last_bit + 1) {
			last_bit = next_bit;
			nvecs++;
		} else if (xfs_buf_offset(bp, next_bit * XFS_BLI_CHUNK) !=
			   (xfs_buf_offset(bp, last_bit * XFS_BLI_CHUNK) +
			    XFS_BLI_CHUNK)) {
			last_bit = next_bit;
			nvecs++;
		} else {
			last_bit++;
		}
	}

	xfs_buf_item_trace("SIZE NORM", bip);
	return nvecs;
}

/*
 * This is called to fill in the vector of log iovecs for the
 * given log buf item.  It fills the first entry with a buf log
 * format structure, and the rest point to contiguous chunks
 * within the buffer.
 */
STATIC void
xfs_buf_item_format(
	xfs_buf_log_item_t	*bip,
	xfs_log_iovec_t		*log_vector)
{
	uint		base_size;
	uint		nvecs;
	xfs_log_iovec_t	*vecp;
	xfs_buf_t	*bp;
	int		first_bit;
	int		last_bit;
	int		next_bit;
	uint		nbits;
	uint		buffer_offset;

	ASSERT(atomic_read(&bip->bli_refcount) > 0);
	ASSERT((bip->bli_flags & XFS_BLI_LOGGED) ||
	       (bip->bli_flags & XFS_BLI_STALE));
	bp = bip->bli_buf;
	vecp = log_vector;

	/*
	 * The size of the base structure is the size of the
	 * declared structure plus the space for the extra words
	 * of the bitmap.  We subtract one from the map size, because
	 * the first element of the bitmap is accounted for in the
	 * size of the base structure.
	 */
	base_size =
		(uint)(sizeof(xfs_buf_log_format_t) +
		       ((bip->bli_format.blf_map_size - 1) * sizeof(uint)));
	vecp->i_addr = (xfs_caddr_t)&bip->bli_format;
	vecp->i_len = base_size;
	XLOG_VEC_SET_TYPE(vecp, XLOG_REG_TYPE_BFORMAT);
	vecp++;
	nvecs = 1;

	if (bip->bli_flags & XFS_BLI_STALE) {
		/*
		 * The buffer is stale, so all we need to log
		 * is the buf log format structure with the
		 * cancel flag in it.
		 */
		xfs_buf_item_trace("FORMAT STALE", bip);
		ASSERT(bip->bli_format.blf_flags & XFS_BLI_CANCEL);
		bip->bli_format.blf_size = nvecs;
		return;
	}

	/*
	 * Fill in an iovec for each set of contiguous chunks.
	 */
	first_bit = xfs_next_bit(bip->bli_format.blf_data_map,
					 bip->bli_format.blf_map_size, 0);
	ASSERT(first_bit != -1);
	last_bit = first_bit;
	nbits = 1;
	for (;;) {
		/*
		 * This takes the bit number to start looking from and
		 * returns the next set bit from there.  It returns -1
		 * if there are no more bits set or the start bit is
		 * beyond the end of the bitmap.
		 */
		next_bit = xfs_next_bit(bip->bli_format.blf_data_map,
						 bip->bli_format.blf_map_size,
						 (uint)last_bit + 1);
		/*
		 * If we run out of bits fill in the last iovec and get
		 * out of the loop.
		 * Else if we start a new set of bits then fill in the
		 * iovec for the series we were looking at and start
		 * counting the bits in the new one.
		 * Else we're still in the same set of bits so just
		 * keep counting and scanning.
		 */
		if (next_bit == -1) {
			buffer_offset = first_bit * XFS_BLI_CHUNK;
			vecp->i_addr = xfs_buf_offset(bp, buffer_offset);
			vecp->i_len = nbits * XFS_BLI_CHUNK;
			XLOG_VEC_SET_TYPE(vecp, XLOG_REG_TYPE_BCHUNK);
			nvecs++;
			break;
		} else if (next_bit != last_bit + 1) {
			buffer_offset = first_bit * XFS_BLI_CHUNK;
			vecp->i_addr = xfs_buf_offset(bp, buffer_offset);
			vecp->i_len = nbits * XFS_BLI_CHUNK;
			XLOG_VEC_SET_TYPE(vecp, XLOG_REG_TYPE_BCHUNK);
			nvecs++;
			vecp++;
			first_bit = next_bit;
			last_bit = next_bit;
			nbits = 1;
		} else if (xfs_buf_offset(bp, next_bit << XFS_BLI_SHIFT) !=
			   (xfs_buf_offset(bp, last_bit << XFS_BLI_SHIFT) +
			    XFS_BLI_CHUNK)) {
			buffer_offset = first_bit * XFS_BLI_CHUNK;
			vecp->i_addr = xfs_buf_offset(bp, buffer_offset);
			vecp->i_len = nbits * XFS_BLI_CHUNK;
			XLOG_VEC_SET_TYPE(vecp, XLOG_REG_TYPE_BCHUNK);
/* You would think we need to bump the nvecs here too, but we do not
 * this number is used by recovery, and it gets confused by the boundary
 * split here
 *			nvecs++;
 */
			vecp++;
			first_bit = next_bit;
			last_bit = next_bit;
			nbits = 1;
		} else {
			last_bit++;
			nbits++;
		}
	}
	bip->bli_format.blf_size = nvecs;

	/*
	 * Check to make sure everything is consistent.
	 */
	xfs_buf_item_trace("FORMAT NORM", bip);
	xfs_buf_item_log_check(bip);
}

/*
 * This is called to pin the buffer associated with the buf log
 * item in memory so it cannot be written out.  Simply call bpin()
 * on the buffer to do this.
 */
STATIC void
xfs_buf_item_pin(
	xfs_buf_log_item_t	*bip)
{
	xfs_buf_t	*bp;

	bp = bip->bli_buf;
	ASSERT(XFS_BUF_ISBUSY(bp));
	ASSERT(atomic_read(&bip->bli_refcount) > 0);
	ASSERT((bip->bli_flags & XFS_BLI_LOGGED) ||
	       (bip->bli_flags & XFS_BLI_STALE));
	xfs_buf_item_trace("PIN", bip);
	xfs_buftrace("XFS_PIN", bp);
	xfs_bpin(bp);
}


/*
 * This is called to unpin the buffer associated with the buf log
 * item which was previously pinned with a call to xfs_buf_item_pin().
 * Just call bunpin() on the buffer to do this.
 *
 * Also drop the reference to the buf item for the current transaction.
 * If the XFS_BLI_STALE flag is set and we are the last reference,
 * then free up the buf log item and unlock the buffer.
 */
STATIC void
xfs_buf_item_unpin(
	xfs_buf_log_item_t	*bip,
	int			stale)
{
	xfs_mount_t	*mp;
	xfs_buf_t	*bp;
	int		freed;
	SPLDECL(s);

	bp = bip->bli_buf;
	ASSERT(bp != NULL);
	ASSERT(XFS_BUF_FSPRIVATE(bp, xfs_buf_log_item_t *) == bip);
	ASSERT(atomic_read(&bip->bli_refcount) > 0);
	xfs_buf_item_trace("UNPIN", bip);
	xfs_buftrace("XFS_UNPIN", bp);

	freed = atomic_dec_and_test(&bip->bli_refcount);
	mp = bip->bli_item.li_mountp;
	xfs_bunpin(bp);
	if (freed && stale) {
		ASSERT(bip->bli_flags & XFS_BLI_STALE);