blob: 58d91823fbf58b9147c74b06c04291ca65467ce3 [file] [log] [blame]
/*
* Copyright (c) 2000-2006 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 "libxfs.h"
#include "libxlog.h"
#define xfs_readonly_buftarg(buftarg) (0)
/* avoid set-but-unused var warning. gcc is not very bright. */
#define xlog_clear_stale_blocks(log, taillsn) ({ \
(taillsn) = (taillsn); \
(0); \
})
#define BLK_AVG(blk1, blk2) ((blk1+blk2) >> 1)
/*
* Verify the given count of basic blocks is valid number of blocks
* to specify for an operation involving the given XFS log buffer.
* Returns nonzero if the count is valid, 0 otherwise.
*/
static inline int
xlog_buf_bbcount_valid(
struct xlog *log,
int bbcount)
{
return bbcount > 0 && bbcount <= log->l_logBBsize;
}
/*
* Allocate a buffer to hold log data. The buffer needs to be able
* to map to a range of nbblks basic blocks at any valid (basic
* block) offset within the log.
*/
xfs_buf_t *
xlog_get_bp(
struct xlog *log,
int nbblks)
{
if (!xlog_buf_bbcount_valid(log, nbblks)) {
xfs_warn(log->l_mp, "Invalid block length (0x%x) for buffer",
nbblks);
XFS_ERROR_REPORT(__func__, XFS_ERRLEVEL_HIGH, log->l_mp);
return NULL;
}
/*
* We do log I/O in units of log sectors (a power-of-2
* multiple of the basic block size), so we round up the
* requested size to accommodate the basic blocks required
* for complete log sectors.
*
* In addition, the buffer may be used for a non-sector-
* aligned block offset, in which case an I/O of the
* requested size could extend beyond the end of the
* buffer. If the requested size is only 1 basic block it
* will never straddle a sector boundary, so this won't be
* an issue. Nor will this be a problem if the log I/O is
* done in basic blocks (sector size 1). But otherwise we
* extend the buffer by one extra log sector to ensure
* there's space to accommodate this possibility.
*/
if (nbblks > 1 && log->l_sectBBsize > 1)
nbblks += log->l_sectBBsize;
nbblks = round_up(nbblks, log->l_sectBBsize);
return libxfs_getbufr(log->l_dev, (xfs_daddr_t)-1, nbblks);
}
void
xlog_put_bp(
xfs_buf_t *bp)
{
libxfs_putbufr(bp);
}
/*
* Return the address of the start of the given block number's data
* in a log buffer. The buffer covers a log sector-aligned region.
*/
STATIC char *
xlog_align(
struct xlog *log,
xfs_daddr_t blk_no,
int nbblks,
struct xfs_buf *bp)
{
xfs_daddr_t offset = blk_no & ((xfs_daddr_t)log->l_sectBBsize - 1);
ASSERT(offset + nbblks <= bp->b_length);
return bp->b_addr + BBTOB(offset);
}
/*
* nbblks should be uint, but oh well. Just want to catch that 32-bit length.
*/
int
xlog_bread_noalign(
struct xlog *log,
xfs_daddr_t blk_no,
int nbblks,
struct xfs_buf *bp)
{
if (!xlog_buf_bbcount_valid(log, nbblks)) {
xfs_warn(log->l_mp, "Invalid block length (0x%x) for buffer",
nbblks);
XFS_ERROR_REPORT(__func__, XFS_ERRLEVEL_HIGH, log->l_mp);
return EFSCORRUPTED;
}
blk_no = round_down(blk_no, log->l_sectBBsize);
nbblks = round_up(nbblks, log->l_sectBBsize);
ASSERT(nbblks > 0);
ASSERT(BBTOB(nbblks) <= XFS_BUF_SIZE(bp));
XFS_BUF_SET_ADDR(bp, log->l_logBBstart + blk_no);
XFS_BUF_SET_COUNT(bp, BBTOB(nbblks));
bp->b_error = 0;
return libxfs_readbufr(log->l_dev, XFS_BUF_ADDR(bp), bp, nbblks, 0);
}
int
xlog_bread(
struct xlog *log,
xfs_daddr_t blk_no,
int nbblks,
struct xfs_buf *bp,
char **offset)
{
int error;
error = xlog_bread_noalign(log, blk_no, nbblks, bp);
if (error)
return error;
*offset = xlog_align(log, blk_no, nbblks, bp);
return 0;
}
/*
* Read at an offset into the buffer. Returns with the buffer in it's original
* state regardless of the result of the read.
*/
STATIC int
xlog_bread_offset(
struct xlog *log,
xfs_daddr_t blk_no, /* block to read from */
int nbblks, /* blocks to read */
struct xfs_buf *bp,
char *offset)
{
char *orig_offset = bp->b_addr;
int orig_len = bp->b_bcount;
int error, error2;
error = xfs_buf_associate_memory(bp, offset, BBTOB(nbblks));
if (error)
return error;
error = xlog_bread_noalign(log, blk_no, nbblks, bp);
/* must reset buffer pointer even on error */
error2 = xfs_buf_associate_memory(bp, orig_offset, orig_len);
if (error)
return error;
return error2;
}
/*
* This routine finds (to an approximation) the first block in the physical
* log which contains the given cycle. It uses a binary search algorithm.
* Note that the algorithm can not be perfect because the disk will not
* necessarily be perfect.
*/
int
xlog_find_cycle_start(
struct xlog *log,
struct xfs_buf *bp,
xfs_daddr_t first_blk,
xfs_daddr_t *last_blk,
uint cycle)
{
char *offset;
xfs_daddr_t mid_blk;
xfs_daddr_t end_blk;
uint mid_cycle;
int error;
end_blk = *last_blk;
mid_blk = BLK_AVG(first_blk, end_blk);
while (mid_blk != first_blk && mid_blk != end_blk) {
error = xlog_bread(log, mid_blk, 1, bp, &offset);
if (error)
return error;
mid_cycle = xlog_get_cycle(offset);
if (mid_cycle == cycle)
end_blk = mid_blk; /* last_half_cycle == mid_cycle */
else
first_blk = mid_blk; /* first_half_cycle == mid_cycle */
mid_blk = BLK_AVG(first_blk, end_blk);
}
ASSERT((mid_blk == first_blk && mid_blk+1 == end_blk) ||
(mid_blk == end_blk && mid_blk-1 == first_blk));
*last_blk = end_blk;
return 0;
}
/*
* Check that a range of blocks does not contain stop_on_cycle_no.
* Fill in *new_blk with the block offset where such a block is
* found, or with -1 (an invalid block number) if there is no such
* block in the range. The scan needs to occur from front to back
* and the pointer into the region must be updated since a later
* routine will need to perform another test.
*/
STATIC int
xlog_find_verify_cycle(
struct xlog *log,
xfs_daddr_t start_blk,
int nbblks,
uint stop_on_cycle_no,
xfs_daddr_t *new_blk)
{
xfs_daddr_t i, j;
uint cycle;
xfs_buf_t *bp;
int bufblks;
char *buf = NULL;
int error = 0;
/*
* Greedily allocate a buffer big enough to handle the full
* range of basic blocks we'll be examining. If that fails,
* try a smaller size. We need to be able to read at least
* a log sector, or we're out of luck.
*/
bufblks = 1 << ffs(nbblks);
while (bufblks > log->l_logBBsize)
bufblks >>= 1;
while (!(bp = xlog_get_bp(log, bufblks))) {
bufblks >>= 1;
if (bufblks < log->l_sectBBsize)
return ENOMEM;
}
for (i = start_blk; i < start_blk + nbblks; i += bufblks) {
int bcount;
bcount = min(bufblks, (start_blk + nbblks - i));
error = xlog_bread(log, i, bcount, bp, &buf);
if (error)
goto out;
for (j = 0; j < bcount; j++) {
cycle = xlog_get_cycle(buf);
if (cycle == stop_on_cycle_no) {
*new_blk = i+j;
goto out;
}
buf += BBSIZE;
}
}
*new_blk = -1;
out:
xlog_put_bp(bp);
return error;
}
/*
* Potentially backup over partial log record write.
*
* In the typical case, last_blk is the number of the block directly after
* a good log record. Therefore, we subtract one to get the block number
* of the last block in the given buffer. extra_bblks contains the number
* of blocks we would have read on a previous read. This happens when the
* last log record is split over the end of the physical log.
*
* extra_bblks is the number of blocks potentially verified on a previous
* call to this routine.
*/
STATIC int
xlog_find_verify_log_record(
struct xlog *log,
xfs_daddr_t start_blk,
xfs_daddr_t *last_blk,
int extra_bblks)
{
xfs_daddr_t i;
xfs_buf_t *bp;
char *offset = NULL;
xlog_rec_header_t *head = NULL;
int error = 0;
int smallmem = 0;
int num_blks = *last_blk - start_blk;
int xhdrs;
ASSERT(start_blk != 0 || *last_blk != start_blk);
if (!(bp = xlog_get_bp(log, num_blks))) {
if (!(bp = xlog_get_bp(log, 1)))
return ENOMEM;
smallmem = 1;
} else {
error = xlog_bread(log, start_blk, num_blks, bp, &offset);
if (error)
goto out;
offset += ((num_blks - 1) << BBSHIFT);
}
for (i = (*last_blk) - 1; i >= 0; i--) {
if (i < start_blk) {
/* valid log record not found */
xfs_warn(log->l_mp,
"Log inconsistent (didn't find previous header)");
ASSERT(0);
error = XFS_ERROR(EIO);
goto out;
}
if (smallmem) {
error = xlog_bread(log, i, 1, bp, &offset);
if (error)
goto out;
}
head = (xlog_rec_header_t *)offset;
if (head->h_magicno == cpu_to_be32(XLOG_HEADER_MAGIC_NUM))
break;
if (!smallmem)
offset -= BBSIZE;
}
/*
* We hit the beginning of the physical log & still no header. Return
* to caller. If caller can handle a return of -1, then this routine
* will be called again for the end of the physical log.
*/
if (i == -1) {
error = -1;
goto out;
}
/*
* We have the final block of the good log (the first block
* of the log record _before_ the head. So we check the uuid.
*/
if ((error = xlog_header_check_mount(log->l_mp, head)))
goto out;
/*
* We may have found a log record header before we expected one.
* last_blk will be the 1st block # with a given cycle #. We may end
* up reading an entire log record. In this case, we don't want to
* reset last_blk. Only when last_blk points in the middle of a log
* record do we update last_blk.
*/
if (xfs_sb_version_haslogv2(&log->l_mp->m_sb)) {
uint h_size = be32_to_cpu(head->h_size);
xhdrs = h_size / XLOG_HEADER_CYCLE_SIZE;
if (h_size % XLOG_HEADER_CYCLE_SIZE)
xhdrs++;
} else {
xhdrs = 1;
}
if (*last_blk - i + extra_bblks !=
BTOBB(be32_to_cpu(head->h_len)) + xhdrs)
*last_blk = i;
out:
xlog_put_bp(bp);
return error;
}
/*
* Head is defined to be the point of the log where the next log write
* write could go. This means that incomplete LR writes at the end are
* eliminated when calculating the head. We aren't guaranteed that previous
* LR have complete transactions. We only know that a cycle number of
* current cycle number -1 won't be present in the log if we start writing
* from our current block number.
*
* last_blk contains the block number of the first block with a given
* cycle number.
*
* Return: zero if normal, non-zero if error.
*/
STATIC int
xlog_find_head(
struct xlog *log,
xfs_daddr_t *return_head_blk)
{
xfs_buf_t *bp;
char *offset;
xfs_daddr_t new_blk, first_blk, start_blk, last_blk, head_blk;
int num_scan_bblks;
uint first_half_cycle, last_half_cycle;
uint stop_on_cycle;
int error, log_bbnum = log->l_logBBsize;
/* Is the end of the log device zeroed? */
if ((error = xlog_find_zeroed(log, &first_blk)) == -1) {
*return_head_blk = first_blk;
/* Is the whole lot zeroed? */
if (!first_blk) {
/* Linux XFS shouldn't generate totally zeroed logs -
* mkfs etc write a dummy unmount record to a fresh
* log so we can store the uuid in there
*/
xfs_warn(log->l_mp, "totally zeroed log");
}
return 0;
} else if (error) {
xfs_warn(log->l_mp, "empty log check failed");
return error;
}
first_blk = 0; /* get cycle # of 1st block */
bp = xlog_get_bp(log, 1);
if (!bp)
return ENOMEM;
error = xlog_bread(log, 0, 1, bp, &offset);
if (error)
goto bp_err;
first_half_cycle = xlog_get_cycle(offset);
last_blk = head_blk = log_bbnum - 1; /* get cycle # of last block */
error = xlog_bread(log, last_blk, 1, bp, &offset);
if (error)
goto bp_err;
last_half_cycle = xlog_get_cycle(offset);
ASSERT(last_half_cycle != 0);
/*
* If the 1st half cycle number is equal to the last half cycle number,
* then the entire log is stamped with the same cycle number. In this
* case, head_blk can't be set to zero (which makes sense). The below
* math doesn't work out properly with head_blk equal to zero. Instead,
* we set it to log_bbnum which is an invalid block number, but this
* value makes the math correct. If head_blk doesn't changed through
* all the tests below, *head_blk is set to zero at the very end rather
* than log_bbnum. In a sense, log_bbnum and zero are the same block
* in a circular file.
*/
if (first_half_cycle == last_half_cycle) {
/*
* In this case we believe that the entire log should have
* cycle number last_half_cycle. We need to scan backwards
* from the end verifying that there are no holes still
* containing last_half_cycle - 1. If we find such a hole,
* then the start of that hole will be the new head. The
* simple case looks like
* x | x ... | x - 1 | x
* Another case that fits this picture would be
* x | x + 1 | x ... | x
* In this case the head really is somewhere at the end of the
* log, as one of the latest writes at the beginning was
* incomplete.
* One more case is
* x | x + 1 | x ... | x - 1 | x
* This is really the combination of the above two cases, and
* the head has to end up at the start of the x-1 hole at the
* end of the log.
*
* In the 256k log case, we will read from the beginning to the
* end of the log and search for cycle numbers equal to x-1.
* We don't worry about the x+1 blocks that we encounter,
* because we know that they cannot be the head since the log
* started with x.
*/
head_blk = log_bbnum;
stop_on_cycle = last_half_cycle - 1;
} else {
/*
* In this case we want to find the first block with cycle
* number matching last_half_cycle. We expect the log to be
* some variation on
* x + 1 ... | x ... | x
* The first block with cycle number x (last_half_cycle) will
* be where the new head belongs. First we do a binary search
* for the first occurrence of last_half_cycle. The binary
* search may not be totally accurate, so then we scan back
* from there looking for occurrences of last_half_cycle before
* us. If that backwards scan wraps around the beginning of
* the log, then we look for occurrences of last_half_cycle - 1
* at the end of the log. The cases we're looking for look
* like
* v binary search stopped here
* x + 1 ... | x | x + 1 | x ... | x
* ^ but we want to locate this spot
* or
* <---------> less than scan distance
* x + 1 ... | x ... | x - 1 | x
* ^ we want to locate this spot
*/
stop_on_cycle = last_half_cycle;
if ((error = xlog_find_cycle_start(log, bp, first_blk,
&head_blk, last_half_cycle)))
goto bp_err;
}
/*
* Now validate the answer. Scan back some number of maximum possible
* blocks and make sure each one has the expected cycle number. The
* maximum is determined by the total possible amount of buffering
* in the in-core log. The following number can be made tighter if
* we actually look at the block size of the filesystem.
*/
num_scan_bblks = XLOG_TOTAL_REC_SHIFT(log);
if (head_blk >= num_scan_bblks) {
/*
* We are guaranteed that the entire check can be performed
* in one buffer.
*/
start_blk = head_blk - num_scan_bblks;
if ((error = xlog_find_verify_cycle(log,
start_blk, num_scan_bblks,
stop_on_cycle, &new_blk)))
goto bp_err;
if (new_blk != -1)
head_blk = new_blk;
} else { /* need to read 2 parts of log */
/*
* We are going to scan backwards in the log in two parts.
* First we scan the physical end of the log. In this part
* of the log, we are looking for blocks with cycle number
* last_half_cycle - 1.
* If we find one, then we know that the log starts there, as
* we've found a hole that didn't get written in going around
* the end of the physical log. The simple case for this is
* x + 1 ... | x ... | x - 1 | x
* <---------> less than scan distance
* If all of the blocks at the end of the log have cycle number
* last_half_cycle, then we check the blocks at the start of
* the log looking for occurrences of last_half_cycle. If we
* find one, then our current estimate for the location of the
* first occurrence of last_half_cycle is wrong and we move
* back to the hole we've found. This case looks like
* x + 1 ... | x | x + 1 | x ...
* ^ binary search stopped here
* Another case we need to handle that only occurs in 256k
* logs is
* x + 1 ... | x ... | x+1 | x ...
* ^ binary search stops here
* In a 256k log, the scan at the end of the log will see the
* x + 1 blocks. We need to skip past those since that is
* certainly not the head of the log. By searching for
* last_half_cycle-1 we accomplish that.
*/
ASSERT(head_blk <= INT_MAX &&
(xfs_daddr_t) num_scan_bblks >= head_blk);
start_blk = log_bbnum - (num_scan_bblks - head_blk);
if ((error = xlog_find_verify_cycle(log, start_blk,
num_scan_bblks - (int)head_blk,
(stop_on_cycle - 1), &new_blk)))
goto bp_err;
if (new_blk != -1) {
head_blk = new_blk;
goto validate_head;
}
/*
* Scan beginning of log now. The last part of the physical
* log is good. This scan needs to verify that it doesn't find
* the last_half_cycle.
*/
start_blk = 0;
ASSERT(head_blk <= INT_MAX);
if ((error = xlog_find_verify_cycle(log,
start_blk, (int)head_blk,
stop_on_cycle, &new_blk)))
goto bp_err;
if (new_blk != -1)
head_blk = new_blk;
}
validate_head:
/*
* Now we need to make sure head_blk is not pointing to a block in
* the middle of a log record.
*/
num_scan_bblks = XLOG_REC_SHIFT(log);
if (head_blk >= num_scan_bblks) {
start_blk = head_blk - num_scan_bblks; /* don't read head_blk */
/* start ptr at last block ptr before head_blk */
if ((error = xlog_find_verify_log_record(log, start_blk,
&head_blk, 0)) == -1) {
error = XFS_ERROR(EIO);
goto bp_err;
} else if (error)
goto bp_err;
} else {
start_blk = 0;
ASSERT(head_blk <= INT_MAX);
if ((error = xlog_find_verify_log_record(log, start_blk,
&head_blk, 0)) == -1) {
/* We hit the beginning of the log during our search */
start_blk = log_bbnum - (num_scan_bblks - head_blk);
new_blk = log_bbnum;
ASSERT(start_blk <= INT_MAX &&
(xfs_daddr_t) log_bbnum-start_blk >= 0);
ASSERT(head_blk <= INT_MAX);
if ((error = xlog_find_verify_log_record(log,
start_blk, &new_blk,
(int)head_blk)) == -1) {
error = XFS_ERROR(EIO);
goto bp_err;
} else if (error)
goto bp_err;
if (new_blk != log_bbnum)
head_blk = new_blk;
} else if (error)
goto bp_err;
}
xlog_put_bp(bp);
if (head_blk == log_bbnum)
*return_head_blk = 0;
else
*return_head_blk = head_blk;
/*
* When returning here, we have a good block number. Bad block
* means that during a previous crash, we didn't have a clean break
* from cycle number N to cycle number N-1. In this case, we need
* to find the first block with cycle number N-1.
*/
return 0;
bp_err:
xlog_put_bp(bp);
if (error)
xfs_warn(log->l_mp, "failed to find log head");
return error;
}
/*
* Find the sync block number or the tail of the log.
*
* This will be the block number of the last record to have its
* associated buffers synced to disk. Every log record header has
* a sync lsn embedded in it. LSNs hold block numbers, so it is easy
* to get a sync block number. The only concern is to figure out which
* log record header to believe.
*
* The following algorithm uses the log record header with the largest
* lsn. The entire log record does not need to be valid. We only care
* that the header is valid.
*
* We could speed up search by using current head_blk buffer, but it is not
* available.
*/
int
xlog_find_tail(
struct xlog *log,
xfs_daddr_t *head_blk,
xfs_daddr_t *tail_blk)
{
xlog_rec_header_t *rhead;
xlog_op_header_t *op_head;
char *offset = NULL;
xfs_buf_t *bp;
int error, i, found;
xfs_daddr_t umount_data_blk;
xfs_daddr_t after_umount_blk;
xfs_lsn_t tail_lsn;
int hblks;
found = 0;
/*
* Find previous log record
*/
if ((error = xlog_find_head(log, head_blk)))
return error;
bp = xlog_get_bp(log, 1);
if (!bp)
return ENOMEM;
if (*head_blk == 0) { /* special case */
error = xlog_bread(log, 0, 1, bp, &offset);
if (error)
goto done;
if (xlog_get_cycle(offset) == 0) {
*tail_blk = 0;
/* leave all other log inited values alone */
goto done;
}
}
/*
* Search backwards looking for log record header block
*/
ASSERT(*head_blk < INT_MAX);
for (i = (int)(*head_blk) - 1; i >= 0; i--) {
error = xlog_bread(log, i, 1, bp, &offset);
if (error)
goto done;
if (*(__be32 *)offset == cpu_to_be32(XLOG_HEADER_MAGIC_NUM)) {
found = 1;
break;
}
}
/*
* If we haven't found the log record header block, start looking
* again from the end of the physical log. XXXmiken: There should be
* a check here to make sure we didn't search more than N blocks in
* the previous code.
*/
if (!found) {
for (i = log->l_logBBsize - 1; i >= (int)(*head_blk); i--) {
error = xlog_bread(log, i, 1, bp, &offset);
if (error)
goto done;
if (*(__be32 *)offset ==
cpu_to_be32(XLOG_HEADER_MAGIC_NUM)) {
found = 2;
break;
}
}
}
if (!found) {
xfs_warn(log->l_mp, "%s: couldn't find sync record", __func__);
xlog_put_bp(bp);
ASSERT(0);
return XFS_ERROR(EIO);
}
/* find blk_no of tail of log */
rhead = (xlog_rec_header_t *)offset;
*tail_blk = BLOCK_LSN(be64_to_cpu(rhead->h_tail_lsn));
/*
* Reset log values according to the state of the log when we
* crashed. In the case where head_blk == 0, we bump curr_cycle
* one because the next write starts a new cycle rather than
* continuing the cycle of the last good log record. At this
* point we have guaranteed that all partial log records have been
* accounted for. Therefore, we know that the last good log record
* written was complete and ended exactly on the end boundary
* of the physical log.
*/
log->l_prev_block = i;
log->l_curr_block = (int)*head_blk;
log->l_curr_cycle = be32_to_cpu(rhead->h_cycle);
if (found == 2)
log->l_curr_cycle++;
atomic64_set(&log->l_tail_lsn, be64_to_cpu(rhead->h_tail_lsn));
atomic64_set(&log->l_last_sync_lsn, be64_to_cpu(rhead->h_lsn));
xlog_assign_grant_head(&log->l_reserve_head.grant, log->l_curr_cycle,
BBTOB(log->l_curr_block));
xlog_assign_grant_head(&log->l_write_head.grant, log->l_curr_cycle,
BBTOB(log->l_curr_block));
/*
* Look for unmount record. If we find it, then we know there
* was a clean unmount. Since 'i' could be the last block in
* the physical log, we convert to a log block before comparing
* to the head_blk.
*
* Save the current tail lsn to use to pass to
* xlog_clear_stale_blocks() below. We won't want to clear the
* unmount record if there is one, so we pass the lsn of the
* unmount record rather than the block after it.
*/
if (xfs_sb_version_haslogv2(&log->l_mp->m_sb)) {
int h_size = be32_to_cpu(rhead->h_size);
int h_version = be32_to_cpu(rhead->h_version);
if ((h_version & XLOG_VERSION_2) &&
(h_size > XLOG_HEADER_CYCLE_SIZE)) {
hblks = h_size / XLOG_HEADER_CYCLE_SIZE;
if (h_size % XLOG_HEADER_CYCLE_SIZE)
hblks++;
} else {
hblks = 1;
}
} else {
hblks = 1;
}
after_umount_blk = (i + hblks + (int)
BTOBB(be32_to_cpu(rhead->h_len))) % log->l_logBBsize;
tail_lsn = atomic64_read(&log->l_tail_lsn);
if (*head_blk == after_umount_blk &&
be32_to_cpu(rhead->h_num_logops) == 1) {
umount_data_blk = (i + hblks) % log->l_logBBsize;
error = xlog_bread(log, umount_data_blk, 1, bp, &offset);
if (error)
goto done;
op_head = (xlog_op_header_t *)offset;
if (op_head->oh_flags & XLOG_UNMOUNT_TRANS) {
/*
* Set tail and last sync so that newly written
* log records will point recovery to after the
* current unmount record.
*/
xlog_assign_atomic_lsn(&log->l_tail_lsn,
log->l_curr_cycle, after_umount_blk);
xlog_assign_atomic_lsn(&log->l_last_sync_lsn,
log->l_curr_cycle, after_umount_blk);
*tail_blk = after_umount_blk;
/*
* Note that the unmount was clean. If the unmount
* was not clean, we need to know this to rebuild the
* superblock counters from the perag headers if we
* have a filesystem using non-persistent counters.
*/
log->l_mp->m_flags |= XFS_MOUNT_WAS_CLEAN;
}
}
/*
* Make sure that there are no blocks in front of the head
* with the same cycle number as the head. This can happen
* because we allow multiple outstanding log writes concurrently,
* and the later writes might make it out before earlier ones.
*
* We use the lsn from before modifying it so that we'll never
* overwrite the unmount record after a clean unmount.
*
* Do this only if we are going to recover the filesystem
*
* NOTE: This used to say "if (!readonly)"
* However on Linux, we can & do recover a read-only filesystem.
* We only skip recovery if NORECOVERY is specified on mount,
* in which case we would not be here.
*
* But... if the -device- itself is readonly, just skip this.
* We can't recover this device anyway, so it won't matter.
*/
if (!xfs_readonly_buftarg(log->l_mp->m_logdev_targp))
error = xlog_clear_stale_blocks(log, tail_lsn);
done:
xlog_put_bp(bp);
if (error)
xfs_warn(log->l_mp, "failed to locate log tail");
return error;
}
/*
* Is the log zeroed at all?
*
* The last binary search should be changed to perform an X block read
* once X becomes small enough. You can then search linearly through
* the X blocks. This will cut down on the number of reads we need to do.
*
* If the log is partially zeroed, this routine will pass back the blkno
* of the first block with cycle number 0. It won't have a complete LR
* preceding it.
*
* Return:
* 0 => the log is completely written to
* -1 => use *blk_no as the first block of the log
* >0 => error has occurred
*/
int
xlog_find_zeroed(
struct xlog *log,
xfs_daddr_t *blk_no)
{
xfs_buf_t *bp;
char *offset;
uint first_cycle, last_cycle;
xfs_daddr_t new_blk, last_blk, start_blk;
xfs_daddr_t num_scan_bblks;
int error, log_bbnum = log->l_logBBsize;
*blk_no = 0;
/* check totally zeroed log */
bp = xlog_get_bp(log, 1);
if (!bp)
return ENOMEM;
error = xlog_bread(log, 0, 1, bp, &offset);
if (error)
goto bp_err;
first_cycle = xlog_get_cycle(offset);
if (first_cycle == 0) { /* completely zeroed log */
*blk_no = 0;
xlog_put_bp(bp);
return -1;
}
/* check partially zeroed log */
error = xlog_bread(log, log_bbnum-1, 1, bp, &offset);
if (error)
goto bp_err;
last_cycle = xlog_get_cycle(offset);
if (last_cycle != 0) { /* log completely written to */
xlog_put_bp(bp);
return 0;
} else if (first_cycle != 1) {
/*
* If the cycle of the last block is zero, the cycle of
* the first block must be 1. If it's not, maybe we're
* not looking at a log... Bail out.
*/
xfs_warn(log->l_mp,
"Log inconsistent or not a log (last==0, first!=1)");
error = XFS_ERROR(EINVAL);
goto bp_err;
}
/* we have a partially zeroed log */
last_blk = log_bbnum-1;
if ((error = xlog_find_cycle_start(log, bp, 0, &last_blk, 0)))
goto bp_err;
/*
* Validate the answer. Because there is no way to guarantee that
* the entire log is made up of log records which are the same size,
* we scan over the defined maximum blocks. At this point, the maximum
* is not chosen to mean anything special. XXXmiken
*/
num_scan_bblks = XLOG_TOTAL_REC_SHIFT(log);
ASSERT(num_scan_bblks <= INT_MAX);
if (last_blk < num_scan_bblks)
num_scan_bblks = last_blk;
start_blk = last_blk - num_scan_bblks;
/*
* We search for any instances of cycle number 0 that occur before
* our current estimate of the head. What we're trying to detect is
* 1 ... | 0 | 1 | 0...
* ^ binary search ends here
*/
if ((error = xlog_find_verify_cycle(log, start_blk,
(int)num_scan_bblks, 0, &new_blk)))
goto bp_err;
if (new_blk != -1)
last_blk = new_blk;
/*
* Potentially backup over partial log record write. We don't need
* to search the end of the log because we know it is zero.
*/
if ((error = xlog_find_verify_log_record(log, start_blk,
&last_blk, 0)) == -1) {
error = XFS_ERROR(EIO);
goto bp_err;
} else if (error)
goto bp_err;
*blk_no = last_blk;
bp_err:
xlog_put_bp(bp);
if (error)
return error;
return -1;
}
STATIC xlog_recover_t *
xlog_recover_find_tid(
struct hlist_head *head,
xlog_tid_t tid)
{
xlog_recover_t *trans;
struct hlist_node *n;
hlist_for_each_entry(trans, n, head, r_list) {
if (trans->r_log_tid == tid)
return trans;
}
return NULL;
}
STATIC void
xlog_recover_new_tid(
struct hlist_head *head,
xlog_tid_t tid,
xfs_lsn_t lsn)
{
xlog_recover_t *trans;
trans = kmem_zalloc(sizeof(xlog_recover_t), KM_SLEEP);
trans->r_log_tid = tid;
trans->r_lsn = lsn;
INIT_LIST_HEAD(&trans->r_itemq);
INIT_HLIST_NODE(&trans->r_list);
hlist_add_head(&trans->r_list, head);
}
STATIC void
xlog_recover_add_item(
struct list_head *head)
{
xlog_recover_item_t *item;
item = kmem_zalloc(sizeof(xlog_recover_item_t), KM_SLEEP);
INIT_LIST_HEAD(&item->ri_list);
list_add_tail(&item->ri_list, head);
}
#define BLK_AVG(blk1, blk2) ((blk1+blk2) >> 1)
STATIC int
xlog_recover_add_to_cont_trans(
struct xlog *log,
struct xlog_recover *trans,
char *dp,
int len)
{
xlog_recover_item_t *item;
char *ptr, *old_ptr;
int old_len;
if (list_empty(&trans->r_itemq)) {
/* finish copying rest of trans header */
xlog_recover_add_item(&trans->r_itemq);
ptr = (char *) &trans->r_theader +
sizeof(xfs_trans_header_t) - len;
memcpy(ptr, dp, len); /* d, s, l */
return 0;
}
/* take the tail entry */
item = list_entry(trans->r_itemq.prev, xlog_recover_item_t, ri_list);
old_ptr = item->ri_buf[item->ri_cnt-1].i_addr;
old_len = item->ri_buf[item->ri_cnt-1].i_len;
ptr = kmem_realloc(old_ptr, len+old_len, KM_SLEEP);
memcpy(&ptr[old_len], dp, len); /* d, s, l */
item->ri_buf[item->ri_cnt-1].i_len += len;
item->ri_buf[item->ri_cnt-1].i_addr = ptr;
trace_xfs_log_recover_item_add_cont(log, trans, item, 0);
return 0;
}
/*
* The next region to add is the start of a new region. It could be
* a whole region or it could be the first part of a new region. Because
* of this, the assumption here is that the type and size fields of all
* format structures fit into the first 32 bits of the structure.
*
* This works because all regions must be 32 bit aligned. Therefore, we
* either have both fields or we have neither field. In the case we have
* neither field, the data part of the region is zero length. We only have
* a log_op_header and can throw away the header since a new one will appear
* later. If we have at least 4 bytes, then we can determine how many regions
* will appear in the current log item.
*/
STATIC int
xlog_recover_add_to_trans(
struct xlog *log,
struct xlog_recover *trans,
char *dp,
int len)
{
struct xfs_inode_log_format *in_f; /* any will do */
xlog_recover_item_t *item;
char *ptr;
if (!len)
return 0;
if (list_empty(&trans->r_itemq)) {
/* we need to catch log corruptions here */
if (*(uint *)dp != XFS_TRANS_HEADER_MAGIC) {
xfs_warn(log->l_mp, "%s: bad header magic number",
__func__);
ASSERT(0);
return XFS_ERROR(EIO);
}
if (len == sizeof(xfs_trans_header_t))
xlog_recover_add_item(&trans->r_itemq);
memcpy(&trans->r_theader, dp, len); /* d, s, l */
return 0;
}
ptr = kmem_alloc(len, KM_SLEEP);
memcpy(ptr, dp, len);
in_f = (struct xfs_inode_log_format *)ptr;
/* take the tail entry */
item = list_entry(trans->r_itemq.prev, xlog_recover_item_t, ri_list);
if (item->ri_total != 0 &&
item->ri_total == item->ri_cnt) {
/* tail item is in use, get a new one */
xlog_recover_add_item(&trans->r_itemq);
item = list_entry(trans->r_itemq.prev,
xlog_recover_item_t, ri_list);
}
if (item->ri_total == 0) { /* first region to be added */
if (in_f->ilf_size == 0 ||
in_f->ilf_size > XLOG_MAX_REGIONS_IN_ITEM) {
xfs_warn(log->l_mp,
"bad number of regions (%d) in inode log format",
in_f->ilf_size);
ASSERT(0);
kmem_free(ptr);
return XFS_ERROR(EIO);
}
item->ri_total = in_f->ilf_size;
item->ri_buf =
kmem_zalloc(item->ri_total * sizeof(xfs_log_iovec_t),
KM_SLEEP);
}
ASSERT(item->ri_total > item->ri_cnt);
/* Description region is ri_buf[0] */
item->ri_buf[item->ri_cnt].i_addr = ptr;
item->ri_buf[item->ri_cnt].i_len = len;
item->ri_cnt++;
trace_xfs_log_recover_item_add(log, trans, item, 0);
return 0;
}
/*
* Free up any resources allocated by the transaction
*
* Remember that EFIs, EFDs, and IUNLINKs are handled later.
*/
STATIC void
xlog_recover_free_trans(
struct xlog_recover *trans)
{
xlog_recover_item_t *item, *n;
int i;
list_for_each_entry_safe(item, n, &trans->r_itemq, ri_list) {
/* Free the regions in the item. */
list_del(&item->ri_list);
for (i = 0; i < item->ri_cnt; i++)
kmem_free(item->ri_buf[i].i_addr);
/* Free the item itself */
kmem_free(item->ri_buf);
kmem_free(item);
}
/* Free the transaction recover structure */
kmem_free(trans);
}
/*
* Perform the transaction.
*
* If the transaction modifies a buffer or inode, do it now. Otherwise,
* EFIs and EFDs get queued up by adding entries into the AIL for them.
*/
STATIC int
xlog_recover_commit_trans(
struct xlog *log,
struct xlog_recover *trans,
int pass)
{
int error = 0;
hlist_del(&trans->r_list);
if ((error = xlog_recover_do_trans(log, trans, pass)))
return error;
xlog_recover_free_trans(trans);
return 0;
}
STATIC int
xlog_recover_unmount_trans(
xlog_recover_t *trans)
{
/* Do nothing now */
xfs_warn(log->l_mp, "%s: Unmount LR", __func__);
return 0;
}
/*
* There are two valid states of the r_state field. 0 indicates that the
* transaction structure is in a normal state. We have either seen the
* start of the transaction or the last operation we added was not a partial
* operation. If the last operation we added to the transaction was a
* partial operation, we need to mark r_state with XLOG_WAS_CONT_TRANS.
*
* NOTE: skip LRs with 0 data length.
*/
STATIC int
xlog_recover_process_data(
struct xlog *log,
struct hlist_head rhash[],
struct xlog_rec_header *rhead,
char *dp,
int pass)
{
char *lp;
int num_logops;
xlog_op_header_t *ohead;
xlog_recover_t *trans;
xlog_tid_t tid;
int error;
unsigned long hash;
uint flags;
lp = dp + be32_to_cpu(rhead->h_len);
num_logops = be32_to_cpu(rhead->h_num_logops);
/* check the log format matches our own - else we can't recover */
if (xlog_header_check_recover(log->l_mp, rhead))
return (XFS_ERROR(EIO));
while ((dp < lp) && num_logops) {
ASSERT(dp + sizeof(xlog_op_header_t) <= lp);
ohead = (xlog_op_header_t *)dp;
dp += sizeof(xlog_op_header_t);
if (ohead->oh_clientid != XFS_TRANSACTION &&
ohead->oh_clientid != XFS_LOG) {
xfs_warn(log->l_mp, "%s: bad clientid 0x%x",
__func__, ohead->oh_clientid);
ASSERT(0);
return (XFS_ERROR(EIO));
}
tid = be32_to_cpu(ohead->oh_tid);
hash = XLOG_RHASH(tid);
trans = xlog_recover_find_tid(&rhash[hash], tid);
if (trans == NULL) { /* not found; add new tid */
if (ohead->oh_flags & XLOG_START_TRANS)
xlog_recover_new_tid(&rhash[hash], tid,
be64_to_cpu(rhead->h_lsn));
} else {
if (dp + be32_to_cpu(ohead->oh_len) > lp) {
xfs_warn(log->l_mp, "%s: bad length 0x%x",
__func__, be32_to_cpu(ohead->oh_len));
return (XFS_ERROR(EIO));
}
flags = ohead->oh_flags & ~XLOG_END_TRANS;
if (flags & XLOG_WAS_CONT_TRANS)
flags &= ~XLOG_CONTINUE_TRANS;
switch (flags) {
case XLOG_COMMIT_TRANS:
error = xlog_recover_commit_trans(log,
trans, pass);
break;
case XLOG_UNMOUNT_TRANS:
error = xlog_recover_unmount_trans(trans);
break;
case XLOG_WAS_CONT_TRANS:
error = xlog_recover_add_to_cont_trans(log,
trans, dp,
be32_to_cpu(ohead->oh_len));
break;
case XLOG_START_TRANS:
xfs_warn(log->l_mp, "%s: bad transaction",
__func__);
ASSERT(0);
error = XFS_ERROR(EIO);
break;
case 0:
case XLOG_CONTINUE_TRANS:
error = xlog_recover_add_to_trans(log, trans,
dp, be32_to_cpu(ohead->oh_len));
break;
default:
xfs_warn(log->l_mp, "%s: bad flag 0x%x",
__func__, flags);
ASSERT(0);
error = XFS_ERROR(EIO);
break;
}
if (error)
return error;
}
dp += be32_to_cpu(ohead->oh_len);
num_logops--;
}
return 0;
}
/*
* Upack the log buffer data and crc check it. If the check fails, issue a
* warning if and only if the CRC in the header is non-zero. This makes the
* check an advisory warning, and the zero CRC check will prevent failure
* warnings from being emitted when upgrading the kernel from one that does not
* add CRCs by default.
*
* When filesystems are CRC enabled, this CRC mismatch becomes a fatal log
* corruption failure
*
* XXX: we do not calculate the CRC here yet. It's not clear what we should do
* with CRC errors here in userspace, so we'll address that problem later on.
*/
#define xlog_cksum(l,r,dp,len) ((r)->h_crc)
STATIC int
xlog_unpack_data_crc(
struct xlog_rec_header *rhead,
char *dp,
struct xlog *log)
{
__le32 crc;
crc = xlog_cksum(log, rhead, dp, be32_to_cpu(rhead->h_len));
if (crc != rhead->h_crc) {
if (rhead->h_crc || xfs_sb_version_hascrc(&log->l_mp->m_sb)) {
xfs_alert(log->l_mp,
"log record CRC mismatch: found 0x%x, expected 0x%x.",
le32_to_cpu(rhead->h_crc),
le32_to_cpu(crc));
xfs_hex_dump(dp, 32);
}
/*
* If we've detected a log record corruption, then we can't
* recover past this point. Abort recovery if we are enforcing
* CRC protection by punting an error back up the stack.
*/
if (xfs_sb_version_hascrc(&log->l_mp->m_sb))
return EFSCORRUPTED;
}
return 0;
}
STATIC int
xlog_unpack_data(
struct xlog_rec_header *rhead,
char *dp,
struct xlog *log)
{
int i, j, k;
int error;
error = xlog_unpack_data_crc(rhead, dp, log);
if (error)
return error;
for (i = 0; i < BTOBB(be32_to_cpu(rhead->h_len)) &&
i < (XLOG_HEADER_CYCLE_SIZE / BBSIZE); i++) {
*(__be32 *)dp = *(__be32 *)&rhead->h_cycle_data[i];
dp += BBSIZE;
}
if (xfs_sb_version_haslogv2(&log->l_mp->m_sb)) {
xlog_in_core_2_t *xhdr = (xlog_in_core_2_t *)rhead;
for ( ; i < BTOBB(be32_to_cpu(rhead->h_len)); i++) {
j = i / (XLOG_HEADER_CYCLE_SIZE / BBSIZE);
k = i % (XLOG_HEADER_CYCLE_SIZE / BBSIZE);
*(__be32 *)dp = xhdr[j].hic_xheader.xh_cycle_data[k];
dp += BBSIZE;
}
}
return 0;
}
STATIC int
xlog_valid_rec_header(
struct xlog *log,
struct xlog_rec_header *rhead,
xfs_daddr_t blkno)
{
int hlen;
if (unlikely(rhead->h_magicno != cpu_to_be32(XLOG_HEADER_MAGIC_NUM))) {
XFS_ERROR_REPORT("xlog_valid_rec_header(1)",
XFS_ERRLEVEL_LOW, log->l_mp);
return XFS_ERROR(EFSCORRUPTED);
}
if (unlikely(
(!rhead->h_version ||
(be32_to_cpu(rhead->h_version) & (~XLOG_VERSION_OKBITS))))) {
xfs_warn(log->l_mp, "%s: unrecognised log version (%d).",
__func__, be32_to_cpu(rhead->h_version));
return XFS_ERROR(EIO);
}
/* LR body must have data or it wouldn't have been written */
hlen = be32_to_cpu(rhead->h_len);
if (unlikely( hlen <= 0 || hlen > INT_MAX )) {
XFS_ERROR_REPORT("xlog_valid_rec_header(2)",
XFS_ERRLEVEL_LOW, log->l_mp);
return XFS_ERROR(EFSCORRUPTED);
}
if (unlikely( blkno > log->l_logBBsize || blkno > INT_MAX )) {
XFS_ERROR_REPORT("xlog_valid_rec_header(3)",
XFS_ERRLEVEL_LOW, log->l_mp);
return XFS_ERROR(EFSCORRUPTED);
}
return 0;
}
/*
* Read the log from tail to head and process the log records found.
* Handle the two cases where the tail and head are in the same cycle
* and where the active portion of the log wraps around the end of
* the physical log separately. The pass parameter is passed through
* to the routines called to process the data and is not looked at
* here.
*/
int
xlog_do_recovery_pass(
struct xlog *log,
xfs_daddr_t head_blk,
xfs_daddr_t tail_blk,
int pass)
{
xlog_rec_header_t *rhead;
xfs_daddr_t blk_no;
char *offset;
xfs_buf_t *hbp, *dbp;
int error = 0, h_size;
int bblks, split_bblks;
int hblks, split_hblks, wrapped_hblks;
struct hlist_head rhash[XLOG_RHASH_SIZE];
ASSERT(head_blk != tail_blk);
/*
* Read the header of the tail block and get the iclog buffer size from
* h_size. Use this to tell how many sectors make up the log header.
*/
if (xfs_sb_version_haslogv2(&log->l_mp->m_sb)) {
/*
* When using variable length iclogs, read first sector of
* iclog header and extract the header size from it. Get a
* new hbp that is the correct size.
*/
hbp = xlog_get_bp(log, 1);
if (!hbp)
return ENOMEM;
error = xlog_bread(log, tail_blk, 1, hbp, &offset);
if (error)
goto bread_err1;
rhead = (xlog_rec_header_t *)offset;
error = xlog_valid_rec_header(log, rhead, tail_blk);
if (error)
goto bread_err1;
h_size = be32_to_cpu(rhead->h_size);
if ((be32_to_cpu(rhead->h_version) & XLOG_VERSION_2) &&
(h_size > XLOG_HEADER_CYCLE_SIZE)) {
hblks = h_size / XLOG_HEADER_CYCLE_SIZE;
if (h_size % XLOG_HEADER_CYCLE_SIZE)
hblks++;
xlog_put_bp(hbp);
hbp = xlog_get_bp(log, hblks);
} else {
hblks = 1;
}
} else {
ASSERT(log->l_sectBBsize == 1);
hblks = 1;
hbp = xlog_get_bp(log, 1);
h_size = XLOG_BIG_RECORD_BSIZE;
}
if (!hbp)
return ENOMEM;
dbp = xlog_get_bp(log, BTOBB(h_size));
if (!dbp) {
xlog_put_bp(hbp);
return ENOMEM;
}
memset(rhash, 0, sizeof(rhash));
if (tail_blk <= head_blk) {
for (blk_no = tail_blk; blk_no < head_blk; ) {
error = xlog_bread(log, blk_no, hblks, hbp, &offset);
if (error)
goto bread_err2;
rhead = (xlog_rec_header_t *)offset;
error = xlog_valid_rec_header(log, rhead, blk_no);
if (error)
goto bread_err2;
/* blocks in data section */
bblks = (int)BTOBB(be32_to_cpu(rhead->h_len));
error = xlog_bread(log, blk_no + hblks, bblks, dbp,
&offset);
if (error)
goto bread_err2;
error = xlog_unpack_data(rhead, offset, log);
if (error)
goto bread_err2;
error = xlog_recover_process_data(log,
rhash, rhead, offset, pass);
if (error)
goto bread_err2;
blk_no += bblks + hblks;
}
} else {
/*
* Perform recovery around the end of the physical log.
* When the head is not on the same cycle number as the tail,
* we can't do a sequential recovery as above.
*/
blk_no = tail_blk;
while (blk_no < log->l_logBBsize) {
/*
* Check for header wrapping around physical end-of-log
*/
offset = hbp->b_addr;
split_hblks = 0;
wrapped_hblks = 0;
if (blk_no + hblks <= log->l_logBBsize) {
/* Read header in one read */
error = xlog_bread(log, blk_no, hblks, hbp,
&offset);
if (error)
goto bread_err2;
} else {
/* This LR is split across physical log end */
if (blk_no != log->l_logBBsize) {
/* some data before physical log end */
ASSERT(blk_no <= INT_MAX);
split_hblks = log->l_logBBsize - (int)blk_no;
ASSERT(split_hblks > 0);
error = xlog_bread(log, blk_no,
split_hblks, hbp,
&offset);
if (error)
goto bread_err2;
}
/*
* Note: this black magic still works with
* large sector sizes (non-512) only because:
* - we increased the buffer size originally
* by 1 sector giving us enough extra space
* for the second read;
* - the log start is guaranteed to be sector
* aligned;
* - we read the log end (LR header start)
* _first_, then the log start (LR header end)
* - order is important.
*/
wrapped_hblks = hblks - split_hblks;
error = xlog_bread_offset(log, 0,
wrapped_hblks, hbp,
offset + BBTOB(split_hblks));
if (error)
goto bread_err2;
}
rhead = (xlog_rec_header_t *)offset;
error = xlog_valid_rec_header(log, rhead,
split_hblks ? blk_no : 0);
if (error)
goto bread_err2;
bblks = (int)BTOBB(be32_to_cpu(rhead->h_len));
blk_no += hblks;
/* Read in data for log record */
if (blk_no + bblks <= log->l_logBBsize) {
error = xlog_bread(log, blk_no, bblks, dbp,
&offset);
if (error)
goto bread_err2;
} else {
/* This log record is split across the
* physical end of log */
offset = dbp->b_addr;
split_bblks = 0;
if (blk_no != log->l_logBBsize) {
/* some data is before the physical
* end of log */
ASSERT(!wrapped_hblks);
ASSERT(blk_no <= INT_MAX);
split_bblks =
log->l_logBBsize - (int)blk_no;
ASSERT(split_bblks > 0);
error = xlog_bread(log, blk_no,
split_bblks, dbp,
&offset);
if (error)
goto bread_err2;
}
/*
* Note: this black magic still works with
* large sector sizes (non-512) only because:
* - we increased the buffer size originally
* by 1 sector giving us enough extra space
* for the second read;
* - the log start is guaranteed to be sector
* aligned;
* - we read the log end (LR header start)
* _first_, then the log start (LR header end)
* - order is important.
*/
error = xlog_bread_offset(log, 0,
bblks - split_bblks, dbp,
offset + BBTOB(split_bblks));
if (error)
goto bread_err2;
}
error = xlog_unpack_data(rhead, offset, log);
if (error)
goto bread_err2;
error = xlog_recover_process_data(log, rhash,
rhead, offset, pass);
if (error)
goto bread_err2;
blk_no += bblks;
}
ASSERT(blk_no >= log->l_logBBsize);
blk_no -= log->l_logBBsize;
/* read first part of physical log */
while (blk_no < head_blk) {
error = xlog_bread(log, blk_no, hblks, hbp, &offset);
if (error)
goto bread_err2;
rhead = (xlog_rec_header_t *)offset;
error = xlog_valid_rec_header(log, rhead, blk_no);
if (error)
goto bread_err2;
bblks = (int)BTOBB(be32_to_cpu(rhead->h_len));
error = xlog_bread(log, blk_no+hblks, bblks, dbp,
&offset);
if (error)
goto bread_err2;
error = xlog_unpack_data(rhead, offset, log);
if (error)
goto bread_err2;
error = xlog_recover_process_data(log, rhash,
rhead, offset, pass);
if (error)
goto bread_err2;
blk_no += bblks + hblks;
}
}
bread_err2:
xlog_put_bp(dbp);
bread_err1:
xlog_put_bp(hbp);
return error;
}