Google Git
Sign in
android-kvm / linux / refs/heads/for-upstream/guestmem / . / fs / xfs / xfs_log_recover.c
blob: 0af3d477197b2418170ad99c25dbc695633af9b3 [file] [log] [blame] [edit]
// SPDX-License-Identifier: GPL-2.0
/*
* Copyright (c) 2000-2006 Silicon Graphics, Inc.
* All Rights Reserved.
*/
#include "xfs.h"
#include "xfs_fs.h"
#include "xfs_shared.h"
#include "xfs_format.h"
#include "xfs_log_format.h"
#include "xfs_trans_resv.h"
#include "xfs_bit.h"
#include "xfs_sb.h"
#include "xfs_mount.h"
#include "xfs_defer.h"
#include "xfs_inode.h"
#include "xfs_trans.h"
#include "xfs_log.h"
#include "xfs_log_priv.h"
#include "xfs_log_recover.h"
#include "xfs_trans_priv.h"
#include "xfs_alloc.h"
#include "xfs_ialloc.h"
#include "xfs_trace.h"
#include "xfs_icache.h"
#include "xfs_error.h"
#include "xfs_buf_item.h"
#include "xfs_ag.h"
#include "xfs_quota.h"
#include "xfs_reflink.h"
#define BLK_AVG(blk1, blk2) ((blk1+blk2) >> 1)
STATIC int
xlog_find_zeroed(
struct xlog *,
xfs_daddr_t *);
STATIC int
xlog_clear_stale_blocks(
struct xlog *,
xfs_lsn_t);
STATIC int
xlog_do_recovery_pass(
struct xlog *, xfs_daddr_t, xfs_daddr_t, int, xfs_daddr_t *);
/*
* Sector aligned buffer routines for buffer create/read/write/access
*/
/*
* Verify the log-relative block number and length in basic blocks are valid for
* an operation involving the given XFS log buffer. Returns true if the fields
* are valid, false otherwise.
*/
static inline bool
xlog_verify_bno(
struct xlog *log,
xfs_daddr_t blk_no,
int bbcount)
{
if (blk_no < 0 || blk_no >= log->l_logBBsize)
return false;
if (bbcount <= 0 || (blk_no + bbcount) > log->l_logBBsize)
return false;
return true;
}
/*
* 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 offset within the log.
*/
static char *
xlog_alloc_buffer(
struct xlog *log,
int nbblks)
{
/*
* Pass log block 0 since we don't have an addr yet, buffer will be
* verified on read.
*/
if (XFS_IS_CORRUPT(log->l_mp, !xlog_verify_bno(log, 0, nbblks))) {
xfs_warn(log->l_mp, "Invalid block length (0x%x) for buffer",
nbblks);
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 kvzalloc(BBTOB(nbblks), GFP_KERNEL | __GFP_RETRY_MAYFAIL);
}
/*
* 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 inline unsigned int
xlog_align(
struct xlog *log,
xfs_daddr_t blk_no)
{
return BBTOB(blk_no & ((xfs_daddr_t)log->l_sectBBsize - 1));
}
static int
xlog_do_io(
struct xlog *log,
xfs_daddr_t blk_no,
unsigned int nbblks,
char *data,
enum req_op op)
{
int error;
if (XFS_IS_CORRUPT(log->l_mp, !xlog_verify_bno(log, blk_no, nbblks))) {
xfs_warn(log->l_mp,
"Invalid log block/length (0x%llx, 0x%x) for buffer",
blk_no, nbblks);
return -EFSCORRUPTED;
}
blk_no = round_down(blk_no, log->l_sectBBsize);
nbblks = round_up(nbblks, log->l_sectBBsize);
ASSERT(nbblks > 0);
error = xfs_rw_bdev(log->l_targ->bt_bdev, log->l_logBBstart + blk_no,
BBTOB(nbblks), data, op);
if (error && !xlog_is_shutdown(log)) {
xfs_alert(log->l_mp,
"log recovery %s I/O error at daddr 0x%llx len %d error %d",
op == REQ_OP_WRITE ? "write" : "read",
blk_no, nbblks, error);
}
return error;
}
STATIC int
xlog_bread_noalign(
struct xlog *log,
xfs_daddr_t blk_no,
int nbblks,
char *data)
{
return xlog_do_io(log, blk_no, nbblks, data, REQ_OP_READ);
}
STATIC int
xlog_bread(
struct xlog *log,
xfs_daddr_t blk_no,
int nbblks,
char *data,
char **offset)
{
int error;
error = xlog_do_io(log, blk_no, nbblks, data, REQ_OP_READ);
if (!error)
*offset = data + xlog_align(log, blk_no);
return error;
}
STATIC int
xlog_bwrite(
struct xlog *log,
xfs_daddr_t blk_no,
int nbblks,
char *data)
{
return xlog_do_io(log, blk_no, nbblks, data, REQ_OP_WRITE);
}
#ifdef DEBUG
/*
* dump debug superblock and log record information
*/
STATIC void
xlog_header_check_dump(
xfs_mount_t *mp,
xlog_rec_header_t *head)
{
xfs_debug(mp, "%s: SB : uuid = %pU, fmt = %d",
__func__, &mp->m_sb.sb_uuid, XLOG_FMT);
xfs_debug(mp, " log : uuid = %pU, fmt = %d",
&head->h_fs_uuid, be32_to_cpu(head->h_fmt));
}
#else
#define xlog_header_check_dump(mp, head)
#endif
/*
* check log record header for recovery
*/
STATIC int
xlog_header_check_recover(
xfs_mount_t *mp,
xlog_rec_header_t *head)
{
ASSERT(head->h_magicno == cpu_to_be32(XLOG_HEADER_MAGIC_NUM));
/*
* IRIX doesn't write the h_fmt field and leaves it zeroed
* (XLOG_FMT_UNKNOWN). This stops us from trying to recover
* a dirty log created in IRIX.
*/
if (XFS_IS_CORRUPT(mp, head->h_fmt != cpu_to_be32(XLOG_FMT))) {
xfs_warn(mp,
"dirty log written in incompatible format - can't recover");
xlog_header_check_dump(mp, head);
return -EFSCORRUPTED;
}
if (XFS_IS_CORRUPT(mp, !uuid_equal(&mp->m_sb.sb_uuid,
&head->h_fs_uuid))) {
xfs_warn(mp,
"dirty log entry has mismatched uuid - can't recover");
xlog_header_check_dump(mp, head);
return -EFSCORRUPTED;
}
return 0;
}
/*
* read the head block of the log and check the header
*/
STATIC int
xlog_header_check_mount(
xfs_mount_t *mp,
xlog_rec_header_t *head)
{
ASSERT(head->h_magicno == cpu_to_be32(XLOG_HEADER_MAGIC_NUM));
if (uuid_is_null(&head->h_fs_uuid)) {
/*
* IRIX doesn't write the h_fs_uuid or h_fmt fields. If
* h_fs_uuid is null, we assume this log was last mounted
* by IRIX and continue.
*/
xfs_warn(mp, "null uuid in log - IRIX style log");
} else if (XFS_IS_CORRUPT(mp, !uuid_equal(&mp->m_sb.sb_uuid,
&head->h_fs_uuid))) {
xfs_warn(mp, "log has mismatched uuid - can't recover");
xlog_header_check_dump(mp, head);
return -EFSCORRUPTED;
}
return 0;
}
/*
* 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.
*/
STATIC int
xlog_find_cycle_start(
struct xlog *log,
char *buffer,
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, buffer, &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;
char *buffer;
xfs_daddr_t 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 = roundup_pow_of_two(nbblks);
while (bufblks > log->l_logBBsize)
bufblks >>= 1;
while (!(buffer = xlog_alloc_buffer(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, buffer, &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:
kvfree(buffer);
return error;
}
static inline int
xlog_logrec_hblks(struct xlog *log, struct xlog_rec_header *rh)
{
if (xfs_has_logv2(log->l_mp)) {
int h_size = be32_to_cpu(rh->h_size);
if ((be32_to_cpu(rh->h_version) & XLOG_VERSION_2) &&
h_size > XLOG_HEADER_CYCLE_SIZE)
return DIV_ROUND_UP(h_size, XLOG_HEADER_CYCLE_SIZE);
}
return 1;
}
/*
* 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;
char *buffer;
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);
buffer = xlog_alloc_buffer(log, num_blks);
if (!buffer) {
buffer = xlog_alloc_buffer(log, 1);
if (!buffer)
return -ENOMEM;
smallmem = 1;
} else {
error = xlog_bread(log, start_blk, num_blks, buffer, &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 = -EFSCORRUPTED;
goto out;
}
if (smallmem) {
error = xlog_bread(log, i, 1, buffer, &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.
*/
xhdrs = xlog_logrec_hblks(log, head);
if (*last_blk - i + extra_bblks !=
BTOBB(be32_to_cpu(head->h_len)) + xhdrs)
*last_blk = i;
out:
kvfree(buffer);
return error;
}
/*
* Head is defined to be the point of the log where the next log 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)
{
char *buffer;
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? */
error = xlog_find_zeroed(log, &first_blk);
if (error < 0) {
xfs_warn(log->l_mp, "empty log check failed");
return error;
}
if (error == 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;
}
first_blk = 0; /* get cycle # of 1st block */
buffer = xlog_alloc_buffer(log, 1);
if (!buffer)
return -ENOMEM;
error = xlog_bread(log, 0, 1, buffer, &offset);
if (error)
goto out_free_buffer;
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, buffer, &offset);
if (error)
goto out_free_buffer;
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;
error = xlog_find_cycle_start(log, buffer, first_blk, &head_blk,
last_half_cycle);
if (error)
goto out_free_buffer;
}
/*
* 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 = min_t(int, log_bbnum, 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 out_free_buffer;
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 out_free_buffer;
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 out_free_buffer;
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 */
error = xlog_find_verify_log_record(log, start_blk, &head_blk, 0);
if (error == 1)
error = -EIO;
if (error)
goto out_free_buffer;
} else {
start_blk = 0;
ASSERT(head_blk <= INT_MAX);
error = xlog_find_verify_log_record(log, start_blk, &head_blk, 0);
if (error < 0)
goto out_free_buffer;
if (error == 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);
error = xlog_find_verify_log_record(log, start_blk,
&new_blk, (int)head_blk);
if (error == 1)
error = -EIO;
if (error)
goto out_free_buffer;
if (new_blk != log_bbnum)
head_blk = new_blk;
} else if (error)
goto out_free_buffer;
}
kvfree(buffer);
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;
out_free_buffer:
kvfree(buffer);
if (error)
xfs_warn(log->l_mp, "failed to find log head");
return error;
}
/*
* Seek backwards in the log for log record headers.
*
* Given a starting log block, walk backwards until we find the provided number
* of records or hit the provided tail block. The return value is the number of
* records encountered or a negative error code. The log block and buffer
* pointer of the last record seen are returned in rblk and rhead respectively.
*/
STATIC int
xlog_rseek_logrec_hdr(
struct xlog *log,
xfs_daddr_t head_blk,
xfs_daddr_t tail_blk,
int count,
char *buffer,
xfs_daddr_t *rblk,
struct xlog_rec_header **rhead,
bool *wrapped)
{
int i;
int error;
int found = 0;
char *offset = NULL;
xfs_daddr_t end_blk;
*wrapped = false;
/*
* Walk backwards from the head block until we hit the tail or the first
* block in the log.
*/
end_blk = head_blk > tail_blk ? tail_blk : 0;
for (i = (int) head_blk - 1; i >= end_blk; i--) {
error = xlog_bread(log, i, 1, buffer, &offset);
if (error)
goto out_error;
if (*(__be32 *) offset == cpu_to_be32(XLOG_HEADER_MAGIC_NUM)) {
*rblk = i;
*rhead = (struct xlog_rec_header *) offset;
if (++found == count)
break;
}
}
/*
* If we haven't hit the tail block or the log record header count,
* start looking again from the end of the physical log. Note that
* callers can pass head == tail if the tail is not yet known.
*/
if (tail_blk >= head_blk && found != count) {
for (i = log->l_logBBsize - 1; i >= (int) tail_blk; i--) {
error = xlog_bread(log, i, 1, buffer, &offset);
if (error)
goto out_error;
if (*(__be32 *)offset ==
cpu_to_be32(XLOG_HEADER_MAGIC_NUM)) {
*wrapped = true;
*rblk = i;
*rhead = (struct xlog_rec_header *) offset;
if (++found == count)
break;
}
}
}
return found;
out_error:
return error;
}
/*
* Seek forward in the log for log record headers.
*
* Given head and tail blocks, walk forward from the tail block until we find
* the provided number of records or hit the head block. The return value is the
* number of records encountered or a negative error code. The log block and
* buffer pointer of the last record seen are returned in rblk and rhead
* respectively.
*/
STATIC int
xlog_seek_logrec_hdr(
struct xlog *log,
xfs_daddr_t head_blk,
xfs_daddr_t tail_blk,
int count,
char *buffer,
xfs_daddr_t *rblk,
struct xlog_rec_header **rhead,
bool *wrapped)
{
int i;
int error;
int found = 0;
char *offset = NULL;
xfs_daddr_t end_blk;
*wrapped = false;
/*
* Walk forward from the tail block until we hit the head or the last
* block in the log.
*/
end_blk = head_blk > tail_blk ? head_blk : log->l_logBBsize - 1;
for (i = (int) tail_blk; i <= end_blk; i++) {
error = xlog_bread(log, i, 1, buffer, &offset);
if (error)
goto out_error;
if (*(__be32 *) offset == cpu_to_be32(XLOG_HEADER_MAGIC_NUM)) {
*rblk = i;
*rhead = (struct xlog_rec_header *) offset;
if (++found == count)
break;
}
}
/*
* If we haven't hit the head block or the log record header count,
* start looking again from the start of the physical log.
*/
if (tail_blk > head_blk && found != count) {
for (i = 0; i < (int) head_blk; i++) {
error = xlog_bread(log, i, 1, buffer, &offset);
if (error)
goto out_error;
if (*(__be32 *)offset ==
cpu_to_be32(XLOG_HEADER_MAGIC_NUM)) {
*wrapped = true;
*rblk = i;
*rhead = (struct xlog_rec_header *) offset;
if (++found == count)
break;
}
}
}
return found;
out_error:
return error;
}
/*
* Calculate distance from head to tail (i.e., unused space in the log).
*/
static inline int
xlog_tail_distance(
struct xlog *log,
xfs_daddr_t head_blk,
xfs_daddr_t tail_blk)
{
if (head_blk < tail_blk)
return tail_blk - head_blk;
return tail_blk + (log->l_logBBsize - head_blk);
}
/*
* Verify the log tail. This is particularly important when torn or incomplete
* writes have been detected near the front of the log and the head has been
* walked back accordingly.
*
* We also have to handle the case where the tail was pinned and the head
* blocked behind the tail right before a crash. If the tail had been pushed
* immediately prior to the crash and the subsequent checkpoint was only
* partially written, it's possible it overwrote the last referenced tail in the
* log with garbage. This is not a coherency problem because the tail must have
* been pushed before it can be overwritten, but appears as log corruption to
* recovery because we have no way to know the tail was updated if the
* subsequent checkpoint didn't write successfully.
*
* Therefore, CRC check the log from tail to head. If a failure occurs and the
* offending record is within max iclog bufs from the head, walk the tail
* forward and retry until a valid tail is found or corruption is detected out
* of the range of a possible overwrite.
*/
STATIC int
xlog_verify_tail(
struct xlog *log,
xfs_daddr_t head_blk,
xfs_daddr_t *tail_blk,
int hsize)
{
struct xlog_rec_header *thead;
char *buffer;
xfs_daddr_t first_bad;
int error = 0;
bool wrapped;
xfs_daddr_t tmp_tail;
xfs_daddr_t orig_tail = *tail_blk;
buffer = xlog_alloc_buffer(log, 1);
if (!buffer)
return -ENOMEM;
/*
* Make sure the tail points to a record (returns positive count on
* success).
*/
error = xlog_seek_logrec_hdr(log, head_blk, *tail_blk, 1, buffer,
&tmp_tail, &thead, &wrapped);
if (error < 0)
goto out;
if (*tail_blk != tmp_tail)
*tail_blk = tmp_tail;
/*
* Run a CRC check from the tail to the head. We can't just check
* MAX_ICLOGS records past the tail because the tail may point to stale
* blocks cleared during the search for the head/tail. These blocks are
* overwritten with zero-length records and thus record count is not a
* reliable indicator of the iclog state before a crash.
*/
first_bad = 0;
error = xlog_do_recovery_pass(log, head_blk, *tail_blk,
XLOG_RECOVER_CRCPASS, &first_bad);
while ((error == -EFSBADCRC || error == -EFSCORRUPTED) && first_bad) {
int tail_distance;
/*
* Is corruption within range of the head? If so, retry from
* the next record. Otherwise return an error.
*/
tail_distance = xlog_tail_distance(log, head_blk, first_bad);
if (tail_distance > BTOBB(XLOG_MAX_ICLOGS * hsize))
break;
/* skip to the next record; returns positive count on success */
error = xlog_seek_logrec_hdr(log, head_blk, first_bad, 2,
buffer, &tmp_tail, &thead, &wrapped);
if (error < 0)
goto out;
*tail_blk = tmp_tail;
first_bad = 0;
error = xlog_do_recovery_pass(log, head_blk, *tail_blk,
XLOG_RECOVER_CRCPASS, &first_bad);
}
if (!error && *tail_blk != orig_tail)
xfs_warn(log->l_mp,
"Tail block (0x%llx) overwrite detected. Updated to 0x%llx",
orig_tail, *tail_blk);
out:
kvfree(buffer);
return error;
}
/*
* Detect and trim torn writes from the head of the log.
*
* Storage without sector atomicity guarantees can result in torn writes in the
* log in the event of a crash. Our only means to detect this scenario is via
* CRC verification. While we can't always be certain that CRC verification
* failure is due to a torn write vs. an unrelated corruption, we do know that
* only a certain number (XLOG_MAX_ICLOGS) of log records can be written out at
* one time. Therefore, CRC verify up to XLOG_MAX_ICLOGS records at the head of
* the log and treat failures in this range as torn writes as a matter of
* policy. In the event of CRC failure, the head is walked back to the last good
* record in the log and the tail is updated from that record and verified.
*/
STATIC int
xlog_verify_head(
struct xlog *log,
xfs_daddr_t *head_blk, /* in/out: unverified head */
xfs_daddr_t *tail_blk, /* out: tail block */
char *buffer,
xfs_daddr_t *rhead_blk, /* start blk of last record */
struct xlog_rec_header **rhead, /* ptr to last record */
bool *wrapped) /* last rec. wraps phys. log */
{
struct xlog_rec_header *tmp_rhead;
char *tmp_buffer;
xfs_daddr_t first_bad;
xfs_daddr_t tmp_rhead_blk;
int found;
int error;
bool tmp_wrapped;
/*
* Check the head of the log for torn writes. Search backwards from the
* head until we hit the tail or the maximum number of log record I/Os
* that could have been in flight at one time. Use a temporary buffer so
* we don't trash the rhead/buffer pointers from the caller.
*/
tmp_buffer = xlog_alloc_buffer(log, 1);
if (!tmp_buffer)
return -ENOMEM;
error = xlog_rseek_logrec_hdr(log, *head_blk, *tail_blk,
XLOG_MAX_ICLOGS, tmp_buffer,
&tmp_rhead_blk, &tmp_rhead, &tmp_wrapped);
kvfree(tmp_buffer);
if (error < 0)
return error;
/*
* Now run a CRC verification pass over the records starting at the
* block found above to the current head. If a CRC failure occurs, the
* log block of the first bad record is saved in first_bad.
*/
error = xlog_do_recovery_pass(log, *head_blk, tmp_rhead_blk,
XLOG_RECOVER_CRCPASS, &first_bad);
if ((error == -EFSBADCRC || error == -EFSCORRUPTED) && first_bad) {
/*
* We've hit a potential torn write. Reset the error and warn
* about it.
*/
error = 0;
xfs_warn(log->l_mp,
"Torn write (CRC failure) detected at log block 0x%llx. Truncating head block from 0x%llx.",
first_bad, *head_blk);
/*
* Get the header block and buffer pointer for the last good
* record before the bad record.
*
* Note that xlog_find_tail() clears the blocks at the new head
* (i.e., the records with invalid CRC) if the cycle number
* matches the current cycle.
*/
found = xlog_rseek_logrec_hdr(log, first_bad, *tail_blk, 1,
buffer, rhead_blk, rhead, wrapped);
if (found < 0)
return found;
if (found == 0) /* XXX: right thing to do here? */
return -EIO;
/*
* Reset the head block to the starting block of the first bad
* log record and set the tail block based on the last good
* record.
*
* Bail out if the updated head/tail match as this indicates
* possible corruption outside of the acceptable
* (XLOG_MAX_ICLOGS) range. This is a job for xfs_repair...
*/
*head_blk = first_bad;
*tail_blk = BLOCK_LSN(be64_to_cpu((*rhead)->h_tail_lsn));
if (*head_blk == *tail_blk) {
ASSERT(0);
return 0;
}
}
if (error)
return error;
return xlog_verify_tail(log, *head_blk, tail_blk,
be32_to_cpu((*rhead)->h_size));
}
/*
* We need to make sure we handle log wrapping properly, so we can't use the
* calculated logbno directly. Make sure it wraps to the correct bno inside the
* log.
*
* The log is limited to 32 bit sizes, so we use the appropriate modulus
* operation here and cast it back to a 64 bit daddr on return.
*/
static inline xfs_daddr_t
xlog_wrap_logbno(
struct xlog *log,
xfs_daddr_t bno)
{
int mod;
div_s64_rem(bno, log->l_logBBsize, &mod);
return mod;
}
/*
* Check whether the head of the log points to an unmount record. In other
* words, determine whether the log is clean. If so, update the in-core state
* appropriately.
*/
static int
xlog_check_unmount_rec(
struct xlog *log,
xfs_daddr_t *head_blk,
xfs_daddr_t *tail_blk,
struct xlog_rec_header *rhead,
xfs_daddr_t rhead_blk,
char *buffer,
bool *clean)
{
struct xlog_op_header *op_head;
xfs_daddr_t umount_data_blk;
xfs_daddr_t after_umount_blk;
int hblks;
int error;
char *offset;
*clean = false;
/*
* 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.
*/
hblks = xlog_logrec_hblks(log, rhead);
after_umount_blk = xlog_wrap_logbno(log,
rhead_blk + hblks + BTOBB(be32_to_cpu(rhead->h_len)));
if (*head_blk == after_umount_blk &&
be32_to_cpu(rhead->h_num_logops) == 1) {
umount_data_blk = xlog_wrap_logbno(log, rhead_blk + hblks);
error = xlog_bread(log, umount_data_blk, 1, buffer, &offset);
if (error)
return error;
op_head = (struct xlog_op_header *)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);
log->l_ailp->ail_head_lsn =
atomic64_read(&log->l_tail_lsn);
*tail_blk = after_umount_blk;
*clean = true;
}
}
return 0;
}
static void
xlog_set_state(
struct xlog *log,
xfs_daddr_t head_blk,
struct xlog_rec_header *rhead,
xfs_daddr_t rhead_blk,
bool bump_cycle)
{
/*
* 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 = rhead_blk;
log->l_curr_block = (int)head_blk;
log->l_curr_cycle = be32_to_cpu(rhead->h_cycle);
if (bump_cycle)
log->l_curr_cycle++;
atomic64_set(&log->l_tail_lsn, be64_to_cpu(rhead->h_tail_lsn));
log->l_ailp->ail_head_lsn = be64_to_cpu(rhead->h_lsn);
}
/*
* 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.
*/
STATIC int
xlog_find_tail(
struct xlog *log,
xfs_daddr_t *head_blk,
xfs_daddr_t *tail_blk)
{
xlog_rec_header_t *rhead;
char *offset = NULL;
char *buffer;
int error;
xfs_daddr_t rhead_blk;
xfs_lsn_t tail_lsn;
bool wrapped = false;
bool clean = false;
/*
* Find previous log record
*/
if ((error = xlog_find_head(log, head_blk)))
return error;
ASSERT(*head_blk < INT_MAX);
buffer = xlog_alloc_buffer(log, 1);
if (!buffer)
return -ENOMEM;
if (*head_blk == 0) { /* special case */
error = xlog_bread(log, 0, 1, buffer, &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 through the log looking for the log record header
* block. This wraps all the way back around to the head so something is
* seriously wrong if we can't find it.
*/
error = xlog_rseek_logrec_hdr(log, *head_blk, *head_blk, 1, buffer,
&rhead_blk, &rhead, &wrapped);
if (error < 0)
goto done;
if (!error) {
xfs_warn(log->l_mp, "%s: couldn't find sync record", __func__);
error = -EFSCORRUPTED;
goto done;
}
*tail_blk = BLOCK_LSN(be64_to_cpu(rhead->h_tail_lsn));
/*
* Set the log state based on the current head record.
*/
xlog_set_state(log, *head_blk, rhead, rhead_blk, wrapped);
tail_lsn = atomic64_read(&log->l_tail_lsn);
/*
* Look for an unmount record at the head of the log. This sets the log
* state to determine whether recovery is necessary.
*/
error = xlog_check_unmount_rec(log, head_blk, tail_blk, rhead,
rhead_blk, buffer, &clean);
if (error)
goto done;
/*
* Verify the log head if the log is not clean (e.g., we have anything
* but an unmount record at the head). This uses CRC verification to
* detect and trim torn writes. If discovered, CRC failures are
* considered torn writes and the log head is trimmed accordingly.
*
* Note that we can only run CRC verification when the log is dirty
* because there's no guarantee that the log data behind an unmount
* record is compatible with the current architecture.
*/
if (!clean) {
xfs_daddr_t orig_head = *head_blk;
error = xlog_verify_head(log, head_blk, tail_blk, buffer,
&rhead_blk, &rhead, &wrapped);
if (error)
goto done;
/* update in-core state again if the head changed */
if (*head_blk != orig_head) {
xlog_set_state(log, *head_blk, rhead, rhead_blk,
wrapped);
tail_lsn = atomic64_read(&log->l_tail_lsn);
error = xlog_check_unmount_rec(log, head_blk, tail_blk,
rhead, rhead_blk, buffer,
&clean);
if (error)
goto done;
}
}
/*
* 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.
*/
if (clean)
xfs_set_clean(log->l_mp);
/*
* 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_targ))
error = xlog_clear_stale_blocks(log, tail_lsn);
done:
kvfree(buffer);
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
*/
STATIC int
xlog_find_zeroed(
struct xlog *log,
xfs_daddr_t *blk_no)
{
char *buffer;
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;
int ret = 1;
*blk_no = 0;
/* check totally zeroed log */
buffer = xlog_alloc_buffer(log, 1);
if (!buffer)
return -ENOMEM;
error = xlog_bread(log, 0, 1, buffer, &offset);
if (error)
goto out_free_buffer;
first_cycle = xlog_get_cycle(offset);
if (first_cycle == 0) { /* completely zeroed log */
*blk_no = 0;
goto out_free_buffer;
}
/* check partially zeroed log */
error = xlog_bread(log, log_bbnum-1, 1, buffer, &offset);
if (error)
goto out_free_buffer;
last_cycle = xlog_get_cycle(offset);
if (last_cycle != 0) { /* log completely written to */
ret = 0;
goto out_free_buffer;
}
/* we have a partially zeroed log */
last_blk = log_bbnum-1;
error = xlog_find_cycle_start(log, buffer, 0, &last_blk, 0);
if (error)
goto out_free_buffer;
/*
* 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 out_free_buffer;
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.
*/
error = xlog_find_verify_log_record(log, start_blk, &last_blk, 0);
if (error == 1)
error = -EIO;
if (error)
goto out_free_buffer;
*blk_no = last_blk;
out_free_buffer:
kvfree(buffer);
if (error)
return error;
return ret;
}
/*
* These are simple subroutines used by xlog_clear_stale_blocks() below
* to initialize a buffer full of empty log record headers and write
* them into the log.
*/
STATIC void
xlog_add_record(
struct xlog *log,
char *buf,
int cycle,
int block,
int tail_cycle,
int tail_block)
{
xlog_rec_header_t *recp = (xlog_rec_header_t *)buf;
memset(buf, 0, BBSIZE);
recp->h_magicno = cpu_to_be32(XLOG_HEADER_MAGIC_NUM);
recp->h_cycle = cpu_to_be32(cycle);
recp->h_version = cpu_to_be32(
xfs_has_logv2(log->l_mp) ? 2 : 1);
recp->h_lsn = cpu_to_be64(xlog_assign_lsn(cycle, block));
recp->h_tail_lsn = cpu_to_be64(xlog_assign_lsn(tail_cycle, tail_block));
recp->h_fmt = cpu_to_be32(XLOG_FMT);
memcpy(&recp->h_fs_uuid, &log->l_mp->m_sb.sb_uuid, sizeof(uuid_t));
}
STATIC int
xlog_write_log_records(
struct xlog *log,
int cycle,
int start_block,
int blocks,
int tail_cycle,
int tail_block)
{
char *offset;
char *buffer;
int balign, ealign;
int sectbb = log->l_sectBBsize;
int end_block = start_block + blocks;
int bufblks;
int error = 0;
int i, j = 0;
/*
* Greedily allocate a buffer big enough to handle the full
* range of basic blocks to be written. If that fails, try
* a smaller size. We need to be able to write at least a
* log sector, or we're out of luck.
*/
bufblks = roundup_pow_of_two(blocks);
while (bufblks > log->l_logBBsize)
bufblks >>= 1;
while (!(buffer = xlog_alloc_buffer(log, bufblks))) {
bufblks >>= 1;
if (bufblks < sectbb)
return -ENOMEM;
}
/* We may need to do a read at the start to fill in part of
* the buffer in the starting sector not covered by the first
* write below.
*/
balign = round_down(start_block, sectbb);
if (balign != start_block) {
error = xlog_bread_noalign(log, start_block, 1, buffer);
if (error)
goto out_free_buffer;
j = start_block - balign;
}
for (i = start_block; i < end_block; i += bufblks) {
int bcount, endcount;
bcount = min(bufblks, end_block - start_block);
endcount = bcount - j;
/* We may need to do a read at the end to fill in part of
* the buffer in the final sector not covered by the write.
* If this is the same sector as the above read, skip it.
*/
ealign = round_down(end_block, sectbb);
if (j == 0 && (start_block + endcount > ealign)) {
error = xlog_bread_noalign(log, ealign, sectbb,
buffer + BBTOB(ealign - start_block));
if (error)
break;
}
offset = buffer + xlog_align(log, start_block);
for (; j < endcount; j++) {
xlog_add_record(log, offset, cycle, i+j,
tail_cycle, tail_block);
offset += BBSIZE;
}
error = xlog_bwrite(log, start_block, endcount, buffer);
if (error)
break;
start_block += endcount;
j = 0;
}
out_free_buffer:
kvfree(buffer);
return error;
}
/*
* This routine is called to blow away any incomplete log writes out
* in front of the log head. We do this so that we won't become confused
* if we come up, write only a little bit more, and then crash again.
* If we leave the partial log records out there, this situation could
* cause us to think those partial writes are valid blocks since they
* have the current cycle number. We get rid of them by overwriting them
* with empty log records with the old cycle number rather than the
* current one.
*
* The tail lsn is passed in rather than taken from
* the log so that we will not write over the unmount record after a
* clean unmount in a 512 block log. Doing so would leave the log without
* any valid log records in it until a new one was written. If we crashed
* during that time we would not be able to recover.
*/
STATIC int
xlog_clear_stale_blocks(
struct xlog *log,
xfs_lsn_t tail_lsn)
{
int tail_cycle, head_cycle;
int tail_block, head_block;
int tail_distance, max_distance;
int distance;
int error;
tail_cycle = CYCLE_LSN(tail_lsn);
tail_block = BLOCK_LSN(tail_lsn);
head_cycle = log->l_curr_cycle;
head_block = log->l_curr_block;
/*
* Figure out the distance between the new head of the log
* and the tail. We want to write over any blocks beyond the
* head that we may have written just before the crash, but
* we don't want to overwrite the tail of the log.
*/
if (head_cycle == tail_cycle) {
/*
* The tail is behind the head in the physical log,
* so the distance from the head to the tail is the
* distance from the head to the end of the log plus
* the distance from the beginning of the log to the
* tail.
*/
if (XFS_IS_CORRUPT(log->l_mp,
head_block < tail_block ||
head_block >= log->l_logBBsize))
return -EFSCORRUPTED;
tail_distance = tail_block + (log->l_logBBsize - head_block);
} else {
/*
* The head is behind the tail in the physical log,
* so the distance from the head to the tail is just
* the tail block minus the head block.
*/
if (XFS_IS_CORRUPT(log->l_mp,
head_block >= tail_block ||
head_cycle != tail_cycle + 1))
return -EFSCORRUPTED;
tail_distance = tail_block - head_block;
}
/*
* If the head is right up against the tail, we can't clear
* anything.
*/
if (tail_distance <= 0) {
ASSERT(tail_distance == 0);
return 0;
}
max_distance = XLOG_TOTAL_REC_SHIFT(log);
/*
* Take the smaller of the maximum amount of outstanding I/O
* we could have and the distance to the tail to clear out.
* We take the smaller so that we don't overwrite the tail and
* we don't waste all day writing from the head to the tail
* for no reason.
*/
max_distance = min(max_distance, tail_distance);
if ((head_block + max_distance) <= log->l_logBBsize) {
/*
* We can stomp all the blocks we need to without
* wrapping around the end of the log. Just do it
* in a single write. Use the cycle number of the
* current cycle minus one so that the log will look like:
* n ... | n - 1 ...
*/
error = xlog_write_log_records(log, (head_cycle - 1),
head_block, max_distance, tail_cycle,
tail_block);
if (error)
return error;
} else {
/*
* We need to wrap around the end of the physical log in
* order to clear all the blocks. Do it in two separate
* I/Os. The first write should be from the head to the
* end of the physical log, and it should use the current
* cycle number minus one just like above.
*/
distance = log->l_logBBsize - head_block;
error = xlog_write_log_records(log, (head_cycle - 1),
head_block, distance, tail_cycle,
tail_block);
if (error)
return error;
/*
* Now write the blocks at the start of the physical log.
* This writes the remainder of the blocks we want to clear.
* It uses the current cycle number since we're now on the
* same cycle as the head so that we get:
* n ... n ... | n - 1 ...
* ^^^^^ blocks we're writing
*/
distance = max_distance - (log->l_logBBsize - head_block);
error = xlog_write_log_records(log, head_cycle, 0, distance,
tail_cycle, tail_block);
if (error)
return error;
}
return 0;
}
/*
* Release the recovered intent item in the AIL that matches the given intent
* type and intent id.
*/
void
xlog_recover_release_intent(
struct xlog *log,
unsigned short intent_type,
uint64_t intent_id)
{
struct xfs_defer_pending *dfp, *n;
list_for_each_entry_safe(dfp, n, &log->r_dfops, dfp_list) {
struct xfs_log_item *lip = dfp->dfp_intent;
if (lip->li_type != intent_type)
continue;
if (!lip->li_ops->iop_match(lip, intent_id))
continue;
ASSERT(xlog_item_is_intent(lip));
xfs_defer_cancel_recovery(log->l_mp, dfp);
}
}
int
xlog_recover_iget(
struct xfs_mount *mp,
xfs_ino_t ino,
struct xfs_inode **ipp)
{
int error;
error = xfs_iget(mp, NULL, ino, 0, 0, ipp);
if (error)
return error;
error = xfs_qm_dqattach(*ipp);
if (error) {
xfs_irele(*ipp);
return error;
}
if (VFS_I(*ipp)->i_nlink == 0)
xfs_iflags_set(*ipp, XFS_IRECOVERY);
return 0;
}
/*
* Get an inode so that we can recover a log operation.
*
* Log intent items that target inodes effectively contain a file handle.
* Check that the generation number matches the intent item like we do for
* other file handles. Log intent items defined after this validation weakness
* was identified must use this function.
*/
int
xlog_recover_iget_handle(
struct xfs_mount *mp,
xfs_ino_t ino,
uint32_t gen,
struct xfs_inode **ipp)
{
struct xfs_inode *ip;
int error;
error = xlog_recover_iget(mp, ino, &ip);
if (error)
return error;
if (VFS_I(ip)->i_generation != gen) {
xfs_irele(ip);
return -EFSCORRUPTED;
}
*ipp = ip;
return 0;
}
/******************************************************************************
*
* Log recover routines
*
******************************************************************************
*/
static const struct xlog_recover_item_ops *xlog_recover_item_ops[] = {
&xlog_buf_item_ops,
&xlog_inode_item_ops,
&xlog_dquot_item_ops,
&xlog_quotaoff_item_ops,
&xlog_icreate_item_ops,
&xlog_efi_item_ops,
&xlog_efd_item_ops,
&xlog_rui_item_ops,
&xlog_rud_item_ops,
&xlog_cui_item_ops,
&xlog_cud_item_ops,
&xlog_bui_item_ops,
&xlog_bud_item_ops,
&xlog_attri_item_ops,
&xlog_attrd_item_ops,
&xlog_xmi_item_ops,
&xlog_xmd_item_ops,
&xlog_rtefi_item_ops,
&xlog_rtefd_item_ops,
};
static const struct xlog_recover_item_ops *
xlog_find_item_ops(
struct xlog_recover_item *item)
{
unsigned int i;
for (i = 0; i < ARRAY_SIZE(xlog_recover_item_ops); i++)
if (ITEM_TYPE(item) == xlog_recover_item_ops[i]->item_type)
return xlog_recover_item_ops[i];
return NULL;
}
/*
* Sort the log items in the transaction.
*
* The ordering constraints are defined by the inode allocation and unlink
* behaviour. The rules are:
*
* 1. Every item is only logged once in a given transaction. Hence it
* represents the last logged state of the item. Hence ordering is
* dependent on the order in which operations need to be performed so
* required initial conditions are always met.
*
* 2. Cancelled buffers are recorded in pass 1 in a separate table and
* there's nothing to replay from them so we can simply cull them
* from the transaction. However, we can't do that until after we've
* replayed all the other items because they may be dependent on the
* cancelled buffer and replaying the cancelled buffer can remove it
* form the cancelled buffer table. Hence they have to be done last.
*
* 3. Inode allocation buffers must be replayed before inode items that
* read the buffer and replay changes into it. For filesystems using the
* ICREATE transactions, this means XFS_LI_ICREATE objects need to get
* treated the same as inode allocation buffers as they create and
* initialise the buffers directly.
*
* 4. Inode unlink buffers must be replayed after inode items are replayed.
* This ensures that inodes are completely flushed to the inode buffer
* in a "free" state before we remove the unlinked inode list pointer.
*
* Hence the ordering needs to be inode allocation buffers first, inode items
* second, inode unlink buffers third and cancelled buffers last.
*
* But there's a problem with that - we can't tell an inode allocation buffer
* apart from a regular buffer, so we can't separate them. We can, however,
* tell an inode unlink buffer from the others, and so we can separate them out
* from all the other buffers and move them to last.
*
* Hence, 4 lists, in order from head to tail:
* - buffer_list for all buffers except cancelled/inode unlink buffers
* - item_list for all non-buffer items
* - inode_buffer_list for inode unlink buffers
* - cancel_list for the cancelled buffers
*
* Note that we add objects to the tail of the lists so that first-to-last
* ordering is preserved within the lists. Adding objects to the head of the
* list means when we traverse from the head we walk them in last-to-first
* order. For cancelled buffers and inode unlink buffers this doesn't matter,
* but for all other items there may be specific ordering that we need to
* preserve.
*/
STATIC int
xlog_recover_reorder_trans(
struct xlog *log,
struct xlog_recover *trans,
int pass)
{
struct xlog_recover_item *item, *n;
int error = 0;
LIST_HEAD(sort_list);
LIST_HEAD(cancel_list);
LIST_HEAD(buffer_list);
LIST_HEAD(inode_buffer_list);
LIST_HEAD(item_list);
list_splice_init(&trans->r_itemq, &sort_list);
list_for_each_entry_safe(item, n, &sort_list, ri_list) {
enum xlog_recover_reorder fate = XLOG_REORDER_ITEM_LIST;
item->ri_ops = xlog_find_item_ops(item);
if (!item->ri_ops) {
xfs_warn(log->l_mp,
"%s: unrecognized type of log operation (%d)",
__func__, ITEM_TYPE(item));
ASSERT(0);
/*
* return the remaining items back to the transaction
* item list so they can be freed in caller.
*/
if (!list_empty(&sort_list))
list_splice_init(&sort_list, &trans->r_itemq);
error = -EFSCORRUPTED;
break;
}
if (item->ri_ops->reorder)
fate = item->ri_ops->reorder(item);
switch (fate) {
case XLOG_REORDER_BUFFER_LIST:
list_move_tail(&item->ri_list, &buffer_list);
break;
case XLOG_REORDER_CANCEL_LIST:
trace_xfs_log_recover_item_reorder_head(log,
trans, item, pass);
list_move(&item->ri_list, &cancel_list);
break;
case XLOG_REORDER_INODE_BUFFER_LIST:
list_move(&item->ri_list, &inode_buffer_list);
break;
case XLOG_REORDER_ITEM_LIST:
trace_xfs_log_recover_item_reorder_tail(log,
trans, item, pass);
list_move_tail(&item->ri_list, &item_list);
break;
}
}
ASSERT(list_empty(&sort_list));
if (!list_empty(&buffer_list))
list_splice(&buffer_list, &trans->r_itemq);
if (!list_empty(&item_list))
list_splice_tail(&item_list, &trans->r_itemq);
if (!list_empty(&inode_buffer_list))
list_splice_tail(&inode_buffer_list, &trans->r_itemq);
if (!list_empty(&cancel_list))
list_splice_tail(&cancel_list, &trans->r_itemq);
return error;
}
void
xlog_buf_readahead(
struct xlog *log,
xfs_daddr_t blkno,
uint len,
const struct xfs_buf_ops *ops)
{
if (!xlog_is_buffer_cancelled(log, blkno, len))
xfs_buf_readahead(log->l_mp->m_ddev_targp, blkno, len, ops);
}
/*
* Create a deferred work structure for resuming and tracking the progress of a
* log intent item that was found during recovery.
*/
void
xlog_recover_intent_item(
struct xlog *log,
struct xfs_log_item *lip,
xfs_lsn_t lsn,
const struct xfs_defer_op_type *ops)
{
ASSERT(xlog_item_is_intent(lip));
xfs_defer_start_recovery(lip, &log->r_dfops, ops);
/*
* Insert the intent into the AIL directly and drop one reference so
* that finishing or canceling the work will drop the other.
*/
xfs_trans_ail_insert(log->l_ailp, lip, lsn);
lip->li_ops->iop_unpin(lip, 0);
}
STATIC int
xlog_recover_items_pass2(
struct xlog *log,
struct xlog_recover *trans,
struct list_head *buffer_list,
struct list_head *item_list)
{
struct xlog_recover_item *item;
int error = 0;
list_for_each_entry(item, item_list, ri_list) {
trace_xfs_log_recover_item_recover(log, trans, item,
XLOG_RECOVER_PASS2);
if (item->ri_ops->commit_pass2)
error = item->ri_ops->commit_pass2(log, buffer_list,
item, trans->r_lsn);
if (error)
return error;
}
return error;
}
/*
* 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,
struct list_head *buffer_list)
{
int error = 0;
int items_queued = 0;
struct xlog_recover_item *item;
struct xlog_recover_item *next;
LIST_HEAD (ra_list);
LIST_HEAD (done_list);
#define XLOG_RECOVER_COMMIT_QUEUE_MAX 100
hlist_del_init(&trans->r_list);
error = xlog_recover_reorder_trans(log, trans, pass);
if (error)
return error;
list_for_each_entry_safe(item, next, &trans->r_itemq, ri_list) {
trace_xfs_log_recover_item_recover(log, trans, item, pass);
switch (pass) {
case XLOG_RECOVER_PASS1:
if (item->ri_ops->commit_pass1)
error = item->ri_ops->commit_pass1(log, item);
break;
case XLOG_RECOVER_PASS2:
if (item->ri_ops->ra_pass2)
item->ri_ops->ra_pass2(log, item);
list_move_tail(&item->ri_list, &ra_list);
items_queued++;
if (items_queued >= XLOG_RECOVER_COMMIT_QUEUE_MAX) {
error = xlog_recover_items_pass2(log, trans,
buffer_list, &ra_list);
list_splice_tail_init(&ra_list, &done_list);
items_queued = 0;
}
break;
default:
ASSERT(0);
}
if (error)
goto out;
}
out:
if (!list_empty(&ra_list)) {
if (!error)
error = xlog_recover_items_pass2(log, trans,
buffer_list, &ra_list);
list_splice_tail_init(&ra_list, &done_list);
}
if (!list_empty(&done_list))
list_splice_init(&done_list, &trans->r_itemq);
return error;
}
STATIC void
xlog_recover_add_item(
struct list_head *head)
{
struct xlog_recover_item *item;
item = kzalloc(sizeof(struct xlog_recover_item),
GFP_KERNEL | __GFP_NOFAIL);
INIT_LIST_HEAD(&item->ri_list);
list_add_tail(&item->ri_list, head);
}
STATIC int
xlog_recover_add_to_cont_trans(
struct xlog *log,
struct xlog_recover *trans,
char *dp,
int len)
{
struct xlog_recover_item *item;
char *ptr, *old_ptr;
int old_len;
/*
* If the transaction is empty, the header was split across this and the
* previous record. Copy the rest of the header.
*/
if (list_empty(&trans->r_itemq)) {
ASSERT(len <= sizeof(struct xfs_trans_header));
if (len > sizeof(struct xfs_trans_header)) {
xfs_warn(log->l_mp, "%s: bad header length", __func__);
return -EFSCORRUPTED;
}
xlog_recover_add_item(&trans->r_itemq);
ptr = (char *)&trans->r_theader +
sizeof(struct xfs_trans_header) - len;
memcpy(ptr, dp, len);
return 0;
}
/* take the tail entry */
item = list_entry(trans->r_itemq.prev, struct xlog_recover_item,
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 = kvrealloc(old_ptr, len + old_len, GFP_KERNEL);
if (!ptr)
return -ENOMEM;
memcpy(&ptr[old_len], dp, len);
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 */
struct xlog_recover_item *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 -EFSCORRUPTED;
}
if (len > sizeof(struct xfs_trans_header)) {
xfs_warn(log->l_mp, "%s: bad header length", __func__);
ASSERT(0);
return -EFSCORRUPTED;
}
/*
* The transaction header can be arbitrarily split across op
* records. If we don't have the whole thing here, copy what we
* do have and handle the rest in the next record.
*/
if (len == sizeof(struct xfs_trans_header))
xlog_recover_add_item(&trans->r_itemq);
memcpy(&trans->r_theader, dp, len);
return 0;
}
ptr = xlog_kvmalloc(len);
memcpy(ptr, dp, len);
in_f = (struct xfs_inode_log_format *)ptr;
/* take the tail entry */
item = list_entry(trans->r_itemq.prev, struct xlog_recover_item,
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,
struct xlog_recover_item, 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);
kvfree(ptr);
return -EFSCORRUPTED;
}
item->ri_total = in_f->ilf_size;
item->ri_buf = kzalloc(item->ri_total * sizeof(xfs_log_iovec_t),
GFP_KERNEL | __GFP_NOFAIL);
}
if (item->ri_total <= item->ri_cnt) {
xfs_warn(log->l_mp,
"log item region count (%d) overflowed size (%d)",
item->ri_cnt, item->ri_total);
ASSERT(0);
kvfree(ptr);
return -EFSCORRUPTED;
}
/* 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)
{
struct xlog_recover_item *item, *n;
int i;
hlist_del_init(&trans->r_list);
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++)
kvfree(item->ri_buf[i].i_addr);
/* Free the item itself */
kfree(item->ri_buf);
kfree(item);
}
/* Free the transaction recover structure */
kfree(trans);
}
/*
* On error or completion, trans is freed.
*/
STATIC int
xlog_recovery_process_trans(
struct xlog *log,
struct xlog_recover *trans,
char *dp,
unsigned int len,
unsigned int flags,
int pass,
struct list_head *buffer_list)
{
int error = 0;
bool freeit = false;
/* mask off ophdr transaction container flags */
flags &= ~XLOG_END_TRANS;
if (flags & XLOG_WAS_CONT_TRANS)
flags &= ~XLOG_CONTINUE_TRANS;
/*
* Callees must not free the trans structure. We'll decide if we need to
* free it or not based on the operation being done and it's result.
*/
switch (flags) {
/* expected flag values */
case 0:
case XLOG_CONTINUE_TRANS:
error = xlog_recover_add_to_trans(log, trans, dp, len);
break;
case XLOG_WAS_CONT_TRANS:
error = xlog_recover_add_to_cont_trans(log, trans, dp, len);
break;
case XLOG_COMMIT_TRANS:
error = xlog_recover_commit_trans(log, trans, pass,
buffer_list);
/* success or fail, we are now done with this transaction. */
freeit = true;
break;
/* unexpected flag values */
case XLOG_UNMOUNT_TRANS:
/* just skip trans */
xfs_warn(log->l_mp, "%s: Unmount LR", __func__);
freeit = true;
break;
case XLOG_START_TRANS:
default:
xfs_warn(log->l_mp, "%s: bad flag 0x%x", __func__, flags);
ASSERT(0);
error = -EFSCORRUPTED;
break;
}
if (error || freeit)
xlog_recover_free_trans(trans);
return error;
}
/*
* Lookup the transaction recovery structure associated with the ID in the
* current ophdr. If the transaction doesn't exist and the start flag is set in
* the ophdr, then allocate a new transaction for future ID matches to find.
* Either way, return what we found during the lookup - an existing transaction
* or nothing.
*/
STATIC struct xlog_recover *
xlog_recover_ophdr_to_trans(
struct hlist_head rhash[],
struct xlog_rec_header *rhead,
struct xlog_op_header *ohead)
{
struct xlog_recover *trans;
xlog_tid_t tid;
struct hlist_head *rhp;
tid = be32_to_cpu(ohead->oh_tid);
rhp = &rhash[XLOG_RHASH(tid)];
hlist_for_each_entry(trans, rhp, r_list) {
if (trans->r_log_tid == tid)
return trans;
}
/*
* skip over non-start transaction headers - we could be
* processing slack space before the next transaction starts
*/
if (!(ohead->oh_flags & XLOG_START_TRANS))
return NULL;
ASSERT(be32_to_cpu(ohead->oh_len) == 0);
/*
* This is a new transaction so allocate a new recovery container to
* hold the recovery ops that will follow.
*/
trans = kzalloc(sizeof(struct xlog_recover), GFP_KERNEL | __GFP_NOFAIL);
trans->r_log_tid = tid;
trans->r_lsn = be64_to_cpu(rhead->h_lsn);
INIT_LIST_HEAD(&trans->r_itemq);
INIT_HLIST_NODE(&trans->r_list);
hlist_add_head(&trans->r_list, rhp);
/*
* Nothing more to do for this ophdr. Items to be added to this new
* transaction will be in subsequent ophdr containers.
*/
return NULL;
}
STATIC int
xlog_recover_process_ophdr(
struct xlog *log,
struct hlist_head rhash[],
struct xlog_rec_header *rhead,
struct xlog_op_header *ohead,
char *dp,
char *end,
int pass,
struct list_head *buffer_list)
{
struct xlog_recover *trans;
unsigned int len;
int error;
/* Do we understand who wrote this op? */
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 -EFSCORRUPTED;
}
/*
* Check the ophdr contains all the data it is supposed to contain.
*/
len = be32_to_cpu(ohead->oh_len);
if (dp + len > end) {
xfs_warn(log->l_mp, "%s: bad length 0x%x", __func__, len);
WARN_ON(1);
return -EFSCORRUPTED;
}
trans = xlog_recover_ophdr_to_trans(rhash, rhead, ohead);
if (!trans) {
/* nothing to do, so skip over this ophdr */
return 0;
}
/*
* The recovered buffer queue is drained only once we know that all
* recovery items for the current LSN have been processed. This is
* required because:
*
* - Buffer write submission updates the metadata LSN of the buffer.
* - Log recovery skips items with a metadata LSN >= the current LSN of
* the recovery item.
* - Separate recovery items against the same metadata buffer can share
* a current LSN. I.e., consider that the LSN of a recovery item is
* defined as the starting LSN of the first record in which its
* transaction appears, that a record can hold multiple transactions,
* and/or that a transaction can span multiple records.
*
* In other words, we are allowed to submit a buffer from log recovery
* once per current LSN. Otherwise, we may incorrectly skip recovery
* items and cause corruption.
*
* We don't know up front whether buffers are updated multiple times per
* LSN. Therefore, track the current LSN of each commit log record as it
* is processed and drain the queue when it changes. Use commit records
* because they are ordered correctly by the logging code.
*/
if (log->l_recovery_lsn != trans->r_lsn &&
ohead->oh_flags & XLOG_COMMIT_TRANS) {
error = xfs_buf_delwri_submit(buffer_list);
if (error)
return error;
log->l_recovery_lsn = trans->r_lsn;
}
return xlog_recovery_process_trans(log, trans, dp, len,
ohead->oh_flags, pass, buffer_list);
}
/*
* 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,
struct list_head *buffer_list)
{
struct xlog_op_header *ohead;
char *end;
int num_logops;
int error;
end = 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 -EIO;
trace_xfs_log_recover_record(log, rhead, pass);
while ((dp < end) && num_logops) {
ohead = (struct xlog_op_header *)dp;
dp += sizeof(*ohead);
if (dp > end) {
xfs_warn(log->l_mp, "%s: op header overrun", __func__);
return -EFSCORRUPTED;
}
/* errors will abort recovery */
error = xlog_recover_process_ophdr(log, rhash, rhead, ohead,
dp, end, pass, buffer_list);
if (error)
return error;
dp += be32_to_cpu(ohead->oh_len);
num_logops--;
}
return 0;
}
/* Take all the collected deferred ops and finish them in order. */
static int
xlog_finish_defer_ops(
struct xfs_mount *mp,
struct list_head *capture_list)
{
struct xfs_defer_capture *dfc, *next;
struct xfs_trans *tp;
int error = 0;
list_for_each_entry_safe(dfc, next, capture_list, dfc_list) {
struct xfs_trans_res resv;
struct xfs_defer_resources dres;
/*
* Create a new transaction reservation from the captured
* information. Set logcount to 1 to force the new transaction
* to regrant every roll so that we can make forward progress
* in recovery no matter how full the log might be.
*/
resv.tr_logres = dfc->dfc_logres;
resv.tr_logcount = 1;
resv.tr_logflags = XFS_TRANS_PERM_LOG_RES;
error = xfs_trans_alloc(mp, &resv, dfc->dfc_blkres,
dfc->dfc_rtxres, XFS_TRANS_RESERVE, &tp);
if (error) {
xlog_force_shutdown(mp->m_log, SHUTDOWN_LOG_IO_ERROR);
return error;
}
/*
* Transfer to this new transaction all the dfops we captured
* from recovering a single intent item.
*/
list_del_init(&dfc->dfc_list);
xfs_defer_ops_continue(dfc, tp, &dres);
error = xfs_trans_commit(tp);
xfs_defer_resources_rele(&dres);
if (error)
return error;
}
ASSERT(list_empty(capture_list));
return 0;
}
/* Release all the captured defer ops and capture structures in this list. */
static void
xlog_abort_defer_ops(
struct xfs_mount *mp,
struct list_head *capture_list)
{
struct xfs_defer_capture *dfc;
struct xfs_defer_capture *next;
list_for_each_entry_safe(dfc, next, capture_list, dfc_list) {
list_del_init(&dfc->dfc_list);
xfs_defer_ops_capture_abort(mp, dfc);
}
}
/*
* When this is called, all of the log intent items which did not have
* corresponding log done items should be in the AIL. What we do now is update
* the data structures associated with each one.
*
* Since we process the log intent items in normal transactions, they will be
* removed at some point after the commit. This prevents us from just walking
* down the list processing each one. We'll use a flag in the intent item to
* skip those that we've already processed and use the AIL iteration mechanism's
* generation count to try to speed this up at least a bit.
*
* When we start, we know that the intents are the only things in the AIL. As we
* process them, however, other items are added to the AIL. Hence we know we
* have started recovery on all the pending intents when we find an non-intent
* item in the AIL.
*/
STATIC int
xlog_recover_process_intents(
struct xlog *log)
{
LIST_HEAD(capture_list);
struct xfs_defer_pending *dfp, *n;
int error = 0;
#if defined(DEBUG) || defined(XFS_WARN)
xfs_lsn_t last_lsn;
last_lsn = xlog_assign_lsn(log->l_curr_cycle, log->l_curr_block);
#endif
list_for_each_entry_safe(dfp, n, &log->r_dfops, dfp_list) {
ASSERT(xlog_item_is_intent(dfp->dfp_intent));
/*
* We should never see a redo item with a LSN higher than
* the last transaction we found in the log at the start
* of recovery.
*/
ASSERT(XFS_LSN_CMP(last_lsn, dfp->dfp_intent->li_lsn) >= 0);
/*
* NOTE: If your intent processing routine can create more
* deferred ops, you /must/ attach them to the capture list in
* the recover routine or else those subsequent intents will be
* replayed in the wrong order!
*
* The recovery function can free the log item, so we must not
* access dfp->dfp_intent after it returns. It must dispose of
* @dfp if it returns 0.
*/
error = xfs_defer_finish_recovery(log->l_mp, dfp,
&capture_list);
if (error)
break;
}
if (error)
goto err;
error = xlog_finish_defer_ops(log->l_mp, &capture_list);
if (error)
goto err;
return 0;
err:
xlog_abort_defer_ops(log->l_mp, &capture_list);
return error;
}
/*
* A cancel occurs when the mount has failed and we're bailing out. Release all
* pending log intent items that we haven't started recovery on so they don't
* pin the AIL.
*/
STATIC void
xlog_recover_cancel_intents(
struct xlog *log)
{
struct xfs_defer_pending *dfp, *n;
list_for_each_entry_safe(dfp, n, &log->r_dfops, dfp_list) {
ASSERT(xlog_item_is_intent(dfp->dfp_intent));
xfs_defer_cancel_recovery(log->l_mp, dfp);
}
}
/*
* Transfer ownership of the recovered pending work to the recovery transaction
* and try to finish the work. If there is more work to be done, the dfp will
* remain attached to the transaction. If not, the dfp is freed.
*/
int
xlog_recover_finish_intent(
struct xfs_trans *tp,
struct xfs_defer_pending *dfp)
{
int error;
list_move(&dfp->dfp_list, &tp->t_dfops);
error = xfs_defer_finish_one(tp, dfp);
if (error == -EAGAIN)
return 0;
return error;
}
/*
* This routine performs a transaction to null out a bad inode pointer
* in an agi unlinked inode hash bucket.
*/
STATIC void
xlog_recover_clear_agi_bucket(
struct xfs_perag *pag,
int bucket)
{
struct xfs_mount *mp = pag_mount(pag);
struct xfs_trans *tp;
struct xfs_agi *agi;
struct xfs_buf *agibp;
int offset;
int error;
error = xfs_trans_alloc(mp, &M_RES(mp)->tr_clearagi, 0, 0, 0, &tp);
if (error)
goto out_error;
error = xfs_read_agi(pag, tp, 0, &agibp);
if (error)
goto out_abort;
agi = agibp->b_addr;
agi->agi_unlinked[bucket] = cpu_to_be32(NULLAGINO);
offset = offsetof(xfs_agi_t, agi_unlinked) +
(sizeof(xfs_agino_t) * bucket);
xfs_trans_log_buf(tp, agibp, offset,
(offset + sizeof(xfs_agino_t) - 1));
error = xfs_trans_commit(tp);
if (error)
goto out_error;
return;
out_abort:
xfs_trans_cancel(tp);
out_error:
xfs_warn(mp, "%s: failed to clear agi %d. Continuing.", __func__,
pag_agno(pag));
return;
}
static int
xlog_recover_iunlink_bucket(
struct xfs_perag *pag,
struct xfs_agi *agi,
int bucket)
{
struct xfs_mount *mp = pag_mount(pag);
struct xfs_inode *prev_ip = NULL;
struct xfs_inode *ip;
xfs_agino_t prev_agino, agino;
int error = 0;
agino = be32_to_cpu(agi->agi_unlinked[bucket]);
while (agino != NULLAGINO) {
error = xfs_iget(mp, NULL, xfs_agino_to_ino(pag, agino), 0, 0,
&ip);
if (error)
break;
ASSERT(VFS_I(ip)->i_nlink == 0);
ASSERT(VFS_I(ip)->i_mode != 0);
xfs_iflags_clear(ip, XFS_IRECOVERY);
agino = ip->i_next_unlinked;
if (prev_ip) {
ip->i_prev_unlinked = prev_agino;
xfs_irele(prev_ip);
/*
* Ensure the inode is removed from the unlinked list
* before we continue so that it won't race with
* building the in-memory list here. This could be
* serialised with the agibp lock, but that just
* serialises via lockstepping and it's much simpler
* just to flush the inodegc queue and wait for it to
* complete.
*/
error = xfs_inodegc_flush(mp);
if (error)
break;
}
prev_agino = agino;
prev_ip = ip;
}
if (prev_ip) {
int error2;
ip->i_prev_unlinked = prev_agino;
xfs_irele(prev_ip);
error2 = xfs_inodegc_flush(mp);
if (error2 && !error)
return error2;
}
return error;
}
/*
* Recover AGI unlinked lists
*
* This is called during recovery to process any inodes which we unlinked but
* not freed when the system crashed. These inodes will be on the lists in the
* AGI blocks. What we do here is scan all the AGIs and fully truncate and free
* any inodes found on the lists. Each inode is removed from the lists when it
* has been fully truncated and is freed. The freeing of the inode and its
* removal from the list must be atomic.
*
* If everything we touch in the agi processing loop is already in memory, this
* loop can hold the cpu for a long time. It runs without lock contention,
* memory allocation contention, the need wait for IO, etc, and so will run
* until we either run out of inodes to process, run low on memory or we run out
* of log space.
*
* This behaviour is bad for latency on single CPU and non-preemptible kernels,
* and can prevent other filesystem work (such as CIL pushes) from running. This
* can lead to deadlocks if the recovery process runs out of log reservation
* space. Hence we need to yield the CPU when there is other kernel work
* scheduled on this CPU to ensure other scheduled work can run without undue
* latency.
*/
static void
xlog_recover_iunlink_ag(
struct xfs_perag *pag)
{
struct xfs_agi *agi;
struct xfs_buf *agibp;
int bucket;
int error;
error = xfs_read_agi(pag, NULL, 0, &agibp);
if (error) {
/*
* AGI is b0rked. Don't process it.
*
* We should probably mark the filesystem as corrupt after we've
* recovered all the ag's we can....
*/
return;
}
/*
* Unlock the buffer so that it can be acquired in the normal course of
* the transaction to truncate and free each inode. Because we are not
* racing with anyone else here for the AGI buffer, we don't even need
* to hold it locked to read the initial unlinked bucket entries out of
* the buffer. We keep buffer reference though, so that it stays pinned
* in memory while we need the buffer.
*/
agi = agibp->b_addr;
xfs_buf_unlock(agibp);
for (bucket = 0; bucket < XFS_AGI_UNLINKED_BUCKETS; bucket++) {
error = xlog_recover_iunlink_bucket(pag, agi, bucket);
if (error) {
/*
* Bucket is unrecoverable, so only a repair scan can
* free the remaining unlinked inodes. Just empty the
* bucket and remaining inodes on it unreferenced and
* unfreeable.
*/
xlog_recover_clear_agi_bucket(pag, bucket);
}
}
xfs_buf_rele(agibp);
}
static void
xlog_recover_process_iunlinks(
struct xlog *log)
{
struct xfs_perag *pag = NULL;
while ((pag = xfs_perag_next(log->l_mp, pag)))
xlog_recover_iunlink_ag(pag);
}
STATIC void
xlog_unpack_data(
struct xlog_rec_header *rhead,
char *dp,
struct xlog *log)
{
int i, j, k;
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_has_logv2(log->l_mp)) {
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;
}
}
}
/*
* CRC check, unpack and process a log record.
*/
STATIC int
xlog_recover_process(
struct xlog *log,
struct hlist_head rhash[],
struct xlog_rec_header *rhead,
char *dp,
int pass,
struct list_head *buffer_list)
{
__le32 old_crc = rhead->h_crc;
__le32 crc;
crc = xlog_cksum(log, rhead, dp, be32_to_cpu(rhead->h_len));
/*
* Nothing else to do if this is a CRC verification pass. Just return
* if this a record with a non-zero crc. Unfortunately, mkfs always
* sets old_crc to 0 so we must consider this valid even on v5 supers.
* Otherwise, return EFSBADCRC on failure so the callers up the stack
* know precisely what failed.
*/
if (pass == XLOG_RECOVER_CRCPASS) {
if (old_crc && crc != old_crc)
return -EFSBADCRC;
return 0;
}
/*
* We're in the normal recovery path. Issue a warning if and only if the
* CRC in the header is non-zero. This is an advisory warning and the
* zero CRC check prevents warnings from being emitted when upgrading
* the kernel from one that does not add CRCs by default.
*/
if (crc != old_crc) {
if (old_crc || xfs_has_crc(log->l_mp)) {
xfs_alert(log->l_mp,
"log record CRC mismatch: found 0x%x, expected 0x%x.",
le32_to_cpu(old_crc),
le32_to_cpu(crc));
xfs_hex_dump(dp, 32);
}
/*
* If the filesystem is CRC enabled, this mismatch becomes a
* fatal log corruption failure.
*/
if (xfs_has_crc(log->l_mp)) {
XFS_ERROR_REPORT(__func__, XFS_ERRLEVEL_LOW, log->l_mp);
return -EFSCORRUPTED;
}
}
xlog_unpack_data(rhead, dp, log);
return xlog_recover_process_data(log, rhash, rhead, dp, pass,
buffer_list);
}
STATIC int
xlog_valid_rec_header(
struct xlog *log,
struct xlog_rec_header *rhead,
xfs_daddr_t blkno,
int bufsize)
{
int hlen;
if (XFS_IS_CORRUPT(log->l_mp,
rhead->h_magicno != cpu_to_be32(XLOG_HEADER_MAGIC_NUM)))
return -EFSCORRUPTED;
if (XFS_IS_CORRUPT(log->l_mp,
(!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 -EFSCORRUPTED;
}
/*
* LR body must have data (or it wouldn't have been written)
* and h_len must not be greater than LR buffer size.
*/
hlen = be32_to_cpu(rhead->h_len);
if (XFS_IS_CORRUPT(log->l_mp, hlen <= 0 || hlen > bufsize))
return -EFSCORRUPTED;
if (XFS_IS_CORRUPT(log->l_mp,
blkno > log->l_logBBsize || blkno > INT_MAX))
return -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.
*/
STATIC int
xlog_do_recovery_pass(
struct xlog *log,
xfs_daddr_t head_blk,
xfs_daddr_t tail_blk,
int pass,
xfs_daddr_t *first_bad) /* out: first bad log rec */
{
xlog_rec_header_t *rhead;
xfs_daddr_t blk_no, rblk_no;
xfs_daddr_t rhead_blk;
char *offset;
char *hbp, *dbp;
int error = 0, h_size, h_len;
int error2 = 0;
int bblks, split_bblks;
int hblks = 1, split_hblks, wrapped_hblks;
int i;
struct hlist_head rhash[XLOG_RHASH_SIZE];
LIST_HEAD (buffer_list);
ASSERT(head_blk != tail_blk);
blk_no = rhead_blk = tail_blk;
for (i = 0; i < XLOG_RHASH_SIZE; i++)
INIT_HLIST_HEAD(&rhash[i]);
hbp = xlog_alloc_buffer(log, hblks);
if (!hbp)
return -ENOMEM;
/*
* 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_has_logv2(log->l_mp)) {
/*
* 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.
*/
error = xlog_bread(log, tail_blk, 1, hbp, &offset);
if (error)
goto bread_err1;
rhead = (xlog_rec_header_t *)offset;
/*
* xfsprogs has a bug where record length is based on lsunit but
* h_size (iclog size) is hardcoded to 32k. Now that we
* unconditionally CRC verify the unmount record, this means the
* log buffer can be too small for the record and cause an
* overrun.
*
* Detect this condition here. Use lsunit for the buffer size as
* long as this looks like the mkfs case. Otherwise, return an
* error to avoid a buffer overrun.
*/
h_size = be32_to_cpu(rhead->h_size);
h_len = be32_to_cpu(rhead->h_len);
if (h_len > h_size && h_len <= log->l_mp->m_logbsize &&
rhead->h_num_logops == cpu_to_be32(1)) {
xfs_warn(log->l_mp,
"invalid iclog size (%d bytes), using lsunit (%d bytes)",
h_size, log->l_mp->m_logbsize);
h_size = log->l_mp->m_logbsize;
}
error = xlog_valid_rec_header(log, rhead, tail_blk, h_size);
if (error)
goto bread_err1;
/*
* This open codes xlog_logrec_hblks so that we can reuse the
* fixed up h_size value calculated above. Without that we'd
* still allocate the buffer based on the incorrect on-disk
* size.
*/
if (h_size > XLOG_HEADER_CYCLE_SIZE &&
(rhead->h_version & cpu_to_be32(XLOG_VERSION_2))) {
hblks = DIV_ROUND_UP(h_size, XLOG_HEADER_CYCLE_SIZE);
if (hblks > 1) {
kvfree(hbp);
hbp = xlog_alloc_buffer(log, hblks);
if (!hbp)
return -ENOMEM;
}
}
} else {
ASSERT(log->l_sectBBsize == 1);
h_size = XLOG_BIG_RECORD_BSIZE;
}
dbp = xlog_alloc_buffer(log, BTOBB(h_size));
if (!dbp) {
kvfree(hbp);
return -ENOMEM;
}
memset(rhash, 0, sizeof(rhash));
if (tail_blk > head_blk) {
/*
* 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.
*/
while (blk_no < log->l_logBBsize) {
/*
* Check for header wrapping around physical end-of-log
*/
offset = hbp;
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_noalign(log, 0,
wrapped_hblks,
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, h_size);
if (error)
goto bread_err2;
bblks = (int)BTOBB(be32_to_cpu(rhead->h_len));
blk_no += hblks;
/*
* Read the log record data in multiple reads if it
* wraps around the end of the log. Note that if the
* header already wrapped, blk_no could point past the
* end of the log. The record data is contiguous in
* that case.
*/
if (blk_no + bblks <= log->l_logBBsize ||
blk_no >= log->l_logBBsize) {
rblk_no = xlog_wrap_logbno(log, blk_no);
error = xlog_bread(log, rblk_no, bblks, dbp,
&offset);
if (error)
goto bread_err2;
} else {
/* This log record is split across the
* physical end of log */
offset = dbp;
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_noalign(log, 0,
bblks - split_bblks,
offset + BBTOB(split_bblks));
if (error)
goto bread_err2;
}
error = xlog_recover_process(log, rhash, rhead, offset,
pass, &buffer_list);
if (error)
goto bread_err2;
blk_no += bblks;
rhead_blk = blk_no;
}
ASSERT(blk_no >= log->l_logBBsize);
blk_no -= log->l_logBBsize;
rhead_blk = blk_no;
}
/* 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, h_size);
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_recover_process(log, rhash, rhead, offset, pass,
&buffer_list);
if (error)
goto bread_err2;
blk_no += bblks + hblks;
rhead_blk = blk_no;
}
bread_err2:
kvfree(dbp);
bread_err1:
kvfree(hbp);
/*
* Submit buffers that have been dirtied by the last record recovered.
*/
if (!list_empty(&buffer_list)) {
if (error) {
/*
* If there has been an item recovery error then we
* cannot allow partial checkpoint writeback to
* occur. We might have multiple checkpoints with the
* same start LSN in this buffer list, and partial
* writeback of a checkpoint in this situation can
* prevent future recovery of all the changes in the
* checkpoints at this start LSN.
*
* Note: Shutting down the filesystem will result in the
* delwri submission marking all the buffers stale,
* completing them and cleaning up _XBF_LOGRECOVERY
* state without doing any IO.
*/
xlog_force_shutdown(log, SHUTDOWN_LOG_IO_ERROR);
}
error2 = xfs_buf_delwri_submit(&buffer_list);
}
if (error && first_bad)
*first_bad = rhead_blk;
/*
* Transactions are freed at commit time but transactions without commit
* records on disk are never committed. Free any that may be left in the
* hash table.
*/
for (i = 0; i < XLOG_RHASH_SIZE; i++) {
struct hlist_node *tmp;
struct xlog_recover *trans;
hlist_for_each_entry_safe(trans, tmp, &rhash[i], r_list)
xlog_recover_free_trans(trans);
}
return error ? error : error2;
}
/*
* Do the recovery of the log. We actually do this in two phases.
* The two passes are necessary in order to implement the function
* of cancelling a record written into the log. The first pass
* determines those things which have been cancelled, and the
* second pass replays log items normally except for those which
* have been cancelled. The handling of the replay and cancellations
* takes place in the log item type specific routines.
*
* The table of items which have cancel records in the log is allocated
* and freed at this level, since only here do we know when all of
* the log recovery has been completed.
*/
STATIC int
xlog_do_log_recovery(
struct xlog *log,
xfs_daddr_t head_blk,
xfs_daddr_t tail_blk)
{
int error;
ASSERT(head_blk != tail_blk);
/*
* First do a pass to find all of the cancelled buf log items.
* Store them in the buf_cancel_table for use in the second pass.
*/
error = xlog_alloc_buf_cancel_table(log);
if (error)
return error;
error = xlog_do_recovery_pass(log, head_blk, tail_blk,
XLOG_RECOVER_PASS1, NULL);
if (error != 0)
goto out_cancel;
/*
* Then do a second pass to actually recover the items in the log.
* When it is complete free the table of buf cancel items.
*/
error = xlog_do_recovery_pass(log, head_blk, tail_blk,
XLOG_RECOVER_PASS2, NULL);
if (!error)
xlog_check_buf_cancel_table(log);
out_cancel:
xlog_free_buf_cancel_table(log);
return error;
}
/*
* Do the actual recovery
*/
STATIC int
xlog_do_recover(
struct xlog *log,
xfs_daddr_t head_blk,
xfs_daddr_t tail_blk)
{
struct xfs_mount *mp = log->l_mp;
struct xfs_buf *bp = mp->m_sb_bp;
struct xfs_sb *sbp = &mp->m_sb;
int error;
trace_xfs_log_recover(log, head_blk, tail_blk);
/*
* First replay the images in the log.
*/
error = xlog_do_log_recovery(log, head_blk, tail_blk);
if (error)
return error;
if (xlog_is_shutdown(log))
return -EIO;
/*
* We now update the tail_lsn since much of the recovery has completed
* and there may be space available to use. If there were no extent or
* iunlinks, we can free up the entire log. This was set in
* xlog_find_tail to be the lsn of the last known good LR on disk. If
* there are extent frees or iunlinks they will have some entries in the
* AIL; so we look at the AIL to determine how to set the tail_lsn.
*/
xfs_ail_assign_tail_lsn(log->l_ailp);
/*
* Now that we've finished replaying all buffer and inode updates,
* re-read the superblock and reverify it.
*/
xfs_buf_lock(bp);
xfs_buf_hold(bp);
error = _xfs_buf_read(bp, XBF_READ);
if (error) {
if (!xlog_is_shutdown(log)) {
xfs_buf_ioerror_alert(bp, __this_address);
ASSERT(0);
}
xfs_buf_relse(bp);
return error;
}
/* Convert superblock from on-disk format */
xfs_sb_from_disk(sbp, bp->b_addr);
xfs_buf_relse(bp);
/* re-initialise in-core superblock and geometry structures */
mp->m_features |= xfs_sb_version_to_features(sbp);
xfs_reinit_percpu_counters(mp);
/* Normal transactions can now occur */
clear_bit(XLOG_ACTIVE_RECOVERY, &log->l_opstate);
return 0;
}
/*
* Perform recovery and re-initialize some log variables in xlog_find_tail.
*
* Return error or zero.
*/
int
xlog_recover(
struct xlog *log)
{
xfs_daddr_t head_blk, tail_blk;
int error;
/* find the tail of the log */
error = xlog_find_tail(log, &head_blk, &tail_blk);
if (error)
return error;
/*
* The superblock was read before the log was available and thus the LSN
* could not be verified. Check the superblock LSN against the current
* LSN now that it's known.
*/
if (xfs_has_crc(log->l_mp) &&
!xfs_log_check_lsn(log->l_mp, log->l_mp->m_sb.sb_lsn))
return -EINVAL;
if (tail_blk != head_blk) {
/* There used to be a comment here:
*
* disallow recovery on read-only mounts. note -- mount
* checks for ENOSPC and turns it into an intelligent
* error message.
* ...but this is no longer true. Now, unless you specify
* NORECOVERY (in which case this function would never be
* called), we just go ahead and recover. We do this all
* under the vfs layer, so we can get away with it unless
* the device itself is read-only, in which case we fail.
*/
if ((error = xfs_dev_is_read_only(log->l_mp, "recovery"))) {
return error;
}
/*
* Version 5 superblock log feature mask validation. We know the
* log is dirty so check if there are any unknown log features
* in what we need to recover. If there are unknown features
* (e.g. unsupported transactions, then simply reject the
* attempt at recovery before touching anything.
*/
if (xfs_sb_is_v5(&log->l_mp->m_sb) &&
xfs_sb_has_incompat_log_feature(&log->l_mp->m_sb,
XFS_SB_FEAT_INCOMPAT_LOG_UNKNOWN)) {
xfs_warn(log->l_mp,
"Superblock has unknown incompatible log features (0x%x) enabled.",
(log->l_mp->m_sb.sb_features_log_incompat &
XFS_SB_FEAT_INCOMPAT_LOG_UNKNOWN));
xfs_warn(log->l_mp,
"The log can not be fully and/or safely recovered by this kernel.");
xfs_warn(log->l_mp,
"Please recover the log on a kernel that supports the unknown features.");
return -EINVAL;
}
/*
* Delay log recovery if the debug hook is set. This is debug
* instrumentation to coordinate simulation of I/O failures with
* log recovery.
*/
if (xfs_globals.log_recovery_delay) {
xfs_notice(log->l_mp,
"Delaying log recovery for %d seconds.",
xfs_globals.log_recovery_delay);
msleep(xfs_globals.log_recovery_delay * 1000);
}
xfs_notice(log->l_mp, "Starting recovery (logdev: %s)",
log->l_mp->m_logname ? log->l_mp->m_logname
: "internal");
error = xlog_do_recover(log, head_blk, tail_blk);
set_bit(XLOG_RECOVERY_NEEDED, &log->l_opstate);
}
return error;
}
/*
* In the first part of recovery we replay inodes and buffers and build up the
* list of intents which need to be processed. Here we process the intents and
* clean up the on disk unlinked inode lists. This is separated from the first
* part of recovery so that the root and real-time bitmap inodes can be read in
* from disk in between the two stages. This is necessary so that we can free
* space in the real-time portion of the file system.
*
* We run this whole process under GFP_NOFS allocation context. We do a
* combination of non-transactional and transactional work, yet we really don't
* want to recurse into the filesystem from direct reclaim during any of this
* processing. This allows all the recovery code run here not to care about the
* memory allocation context it is running in.
*/
int
xlog_recover_finish(
struct xlog *log)
{
unsigned int nofs_flags = memalloc_nofs_save();
int error;
error = xlog_recover_process_intents(log);
if (error) {
/*
* Cancel all the unprocessed intent items now so that we don't
* leave them pinned in the AIL. This can cause the AIL to
* livelock on the pinned item if anyone tries to push the AIL
* (inode reclaim does this) before we get around to
* xfs_log_mount_cancel.
*/
xlog_recover_cancel_intents(log);
xfs_alert(log->l_mp, "Failed to recover intents");
xlog_force_shutdown(log, SHUTDOWN_LOG_IO_ERROR);
goto out_error;
}
/*
* Sync the log to get all the intents out of the AIL. This isn't
* absolutely necessary, but it helps in case the unlink transactions
* would have problems pushing the intents out of the way.
*/
xfs_log_force(log->l_mp, XFS_LOG_SYNC);
xlog_recover_process_iunlinks(log);
/*
* Recover any CoW staging blocks that are still referenced by the
* ondisk refcount metadata. During mount there cannot be any live
* staging extents as we have not permitted any user modifications.
* Therefore, it is safe to free them all right now, even on a
* read-only mount.
*/
error = xfs_reflink_recover_cow(log->l_mp);
if (error) {
xfs_alert(log->l_mp,
"Failed to recover leftover CoW staging extents, err %d.",
error);
/*
* If we get an error here, make sure the log is shut down
* but return zero so that any log items committed since the
* end of intents processing can be pushed through the CIL
* and AIL.
*/
xlog_force_shutdown(log, SHUTDOWN_LOG_IO_ERROR);
error = 0;
goto out_error;
}
out_error:
memalloc_nofs_restore(nofs_flags);
return error;
}
void
xlog_recover_cancel(
struct xlog *log)
{
if (xlog_recovery_needed(log))
xlog_recover_cancel_intents(log);
}