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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:49:45 +0000
commit2c3c1048746a4622d8c89a29670120dc8fab93c4 (patch)
tree848558de17fb3008cdf4d861b01ac7781903ce39 /fs/xfs/xfs_log_recover.c
parentInitial commit. (diff)
downloadlinux-2c3c1048746a4622d8c89a29670120dc8fab93c4.tar.xz
linux-2c3c1048746a4622d8c89a29670120dc8fab93c4.zip
Adding upstream version 6.1.76.upstream/6.1.76
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'fs/xfs/xfs_log_recover.c')
-rw-r--r--fs/xfs/xfs_log_recover.c3517
1 files changed, 3517 insertions, 0 deletions
diff --git a/fs/xfs/xfs_log_recover.c b/fs/xfs/xfs_log_recover.c
new file mode 100644
index 000000000..322eb2ee6
--- /dev/null
+++ b/fs/xfs/xfs_log_recover.c
@@ -0,0 +1,3517 @@
+// 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 = 1 << ffs(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:
+ kmem_free(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:
+ kmem_free(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;
+ }
+
+ kmem_free(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:
+ kmem_free(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:
+ kmem_free(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);
+ kmem_free(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);
+ xlog_assign_atomic_lsn(&log->l_last_sync_lsn,
+ log->l_curr_cycle, after_umount_blk);
+ *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));
+ atomic64_set(&log->l_last_sync_lsn, be64_to_cpu(rhead->h_lsn));
+ xlog_assign_grant_head(&log->l_reserve_head.grant, log->l_curr_cycle,
+ BBTOB(log->l_curr_block));
+ xlog_assign_grant_head(&log->l_write_head.grant, log->l_curr_cycle,
+ BBTOB(log->l_curr_block));
+}
+
+/*
+ * 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)
+ set_bit(XFS_OPSTATE_CLEAN, &log->l_mp->m_opstate);
+
+ /*
+ * 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:
+ kmem_free(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;
+
+ *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;
+ kmem_free(buffer);
+ return 1;
+ }
+
+ /* 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 */
+ kmem_free(buffer);
+ return 0;
+ }
+
+ /* 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:
+ kmem_free(buffer);
+ if (error)
+ return error;
+ return 1;
+}
+
+/*
+ * 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 = 1 << ffs(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:
+ kmem_free(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_ail_cursor cur;
+ struct xfs_log_item *lip;
+ struct xfs_ail *ailp = log->l_ailp;
+
+ spin_lock(&ailp->ail_lock);
+ for (lip = xfs_trans_ail_cursor_first(ailp, &cur, 0); lip != NULL;
+ lip = xfs_trans_ail_cursor_next(ailp, &cur)) {
+ if (lip->li_type != intent_type)
+ continue;
+ if (!lip->li_ops->iop_match(lip, intent_id))
+ continue;
+
+ spin_unlock(&ailp->ail_lock);
+ lip->li_ops->iop_release(lip);
+ spin_lock(&ailp->ail_lock);
+ break;
+ }
+
+ xfs_trans_ail_cursor_done(&cur);
+ spin_unlock(&ailp->ail_lock);
+}
+
+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;
+}
+
+/******************************************************************************
+ *
+ * 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,
+};
+
+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 tobe 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);
+}
+
+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 = kmem_zalloc(sizeof(struct xlog_recover_item), 0);
+ 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, old_len, 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 = kmem_alloc(len, 0);
+ 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);
+ kmem_free(ptr);
+ return -EFSCORRUPTED;
+ }
+
+ item->ri_total = in_f->ilf_size;
+ item->ri_buf =
+ kmem_zalloc(item->ri_total * sizeof(xfs_log_iovec_t),
+ 0);
+ }
+
+ 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);
+ kmem_free(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++)
+ kmem_free(item->ri_buf[i].i_addr);
+ /* Free the item itself */
+ kmem_free(item->ri_buf);
+ kmem_free(item);
+ }
+ /* Free the transaction recover structure */
+ kmem_free(trans);
+}
+
+/*
+ * 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 = kmem_zalloc(sizeof(struct xlog_recover), 0);
+ 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);
+ ASSERT(dp <= end);
+
+ /* 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_free(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_ail_cursor cur;
+ struct xfs_log_item *lip;
+ struct xfs_ail *ailp;
+ int error = 0;
+#if defined(DEBUG) || defined(XFS_WARN)
+ xfs_lsn_t last_lsn;
+#endif
+
+ ailp = log->l_ailp;
+ spin_lock(&ailp->ail_lock);
+#if defined(DEBUG) || defined(XFS_WARN)
+ last_lsn = xlog_assign_lsn(log->l_curr_cycle, log->l_curr_block);
+#endif
+ for (lip = xfs_trans_ail_cursor_first(ailp, &cur, 0);
+ lip != NULL;
+ lip = xfs_trans_ail_cursor_next(ailp, &cur)) {
+ const struct xfs_item_ops *ops;
+
+ if (!xlog_item_is_intent(lip))
+ break;
+
+ /*
+ * 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, lip->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 lip after it returns.
+ */
+ spin_unlock(&ailp->ail_lock);
+ ops = lip->li_ops;
+ error = ops->iop_recover(lip, &capture_list);
+ spin_lock(&ailp->ail_lock);
+ if (error) {
+ trace_xlog_intent_recovery_failed(log->l_mp, error,
+ ops->iop_recover);
+ break;
+ }
+ }
+
+ xfs_trans_ail_cursor_done(&cur);
+ spin_unlock(&ailp->ail_lock);
+ 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_log_item *lip;
+ struct xfs_ail_cursor cur;
+ struct xfs_ail *ailp;
+
+ ailp = log->l_ailp;
+ spin_lock(&ailp->ail_lock);
+ lip = xfs_trans_ail_cursor_first(ailp, &cur, 0);
+ while (lip != NULL) {
+ if (!xlog_item_is_intent(lip))
+ break;
+
+ spin_unlock(&ailp->ail_lock);
+ lip->li_ops->iop_release(lip);
+ spin_lock(&ailp->ail_lock);
+ lip = xfs_trans_ail_cursor_next(ailp, &cur);
+ }
+
+ xfs_trans_ail_cursor_done(&cur);
+ spin_unlock(&ailp->ail_lock);
+}
+
+/*
+ * 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->pag_mount;
+ 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, &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->pag_agno);
+ return;
+}
+
+static int
+xlog_recover_iunlink_bucket(
+ struct xfs_perag *pag,
+ struct xfs_agi *agi,
+ int bucket)
+{
+ struct xfs_mount *mp = pag->pag_mount;
+ 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(mp, pag->pag_agno, 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.
+ */
+ xfs_inodegc_flush(mp);
+ }
+
+ prev_agino = agino;
+ prev_ip = ip;
+ }
+
+ if (prev_ip) {
+ ip->i_prev_unlinked = prev_agino;
+ xfs_irele(prev_ip);
+ }
+ xfs_inodegc_flush(mp);
+ 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, &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.
+ */
+ xfs_inodegc_flush(pag->pag_mount);
+ xlog_recover_clear_agi_bucket(pag, bucket);
+ }
+ }
+
+ xfs_buf_rele(agibp);
+}
+
+static void
+xlog_recover_process_iunlinks(
+ struct xlog *log)
+{
+ struct xfs_perag *pag;
+ xfs_agnumber_t agno;
+
+ for_each_perag(log->l_mp, agno, pag)
+ xlog_recover_iunlink_ag(pag);
+
+ /*
+ * Flush the pending unlinked inodes to ensure that the inactivations
+ * are fully completed on disk and the incore inodes can be reclaimed
+ * before we signal that recovery is complete.
+ */
+ xfs_inodegc_flush(log->l_mp);
+}
+
+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, 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]);
+
+ /*
+ * 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.
+ */
+ hbp = xlog_alloc_buffer(log, 1);
+ if (!hbp)
+ return -ENOMEM;
+
+ error = xlog_bread(log, tail_blk, 1, hbp, &offset);
+ if (error)
+ goto bread_err1;
+
+ rhead = (xlog_rec_header_t *)offset;
+
+ /*
+ * 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;
+
+ hblks = xlog_logrec_hblks(log, rhead);
+ if (hblks != 1) {
+ kmem_free(hbp);
+ hbp = xlog_alloc_buffer(log, hblks);
+ }
+ } else {
+ ASSERT(log->l_sectBBsize == 1);
+ hblks = 1;
+ hbp = xlog_alloc_buffer(log, 1);
+ h_size = XLOG_BIG_RECORD_BSIZE;
+ }
+
+ if (!hbp)
+ return -ENOMEM;
+ dbp = xlog_alloc_buffer(log, BTOBB(h_size));
+ if (!dbp) {
+ kmem_free(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:
+ kmem_free(dbp);
+ bread_err1:
+ kmem_free(hbp);
+
+ /*
+ * Submit buffers that have been added from the last record processed,
+ * regardless of error status.
+ */
+ if (!list_empty(&buffer_list))
+ 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 and set the tail_lsn to
+ * be the last_sync_lsn. 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.
+ */
+ xlog_assign_tail_lsn(mp);
+
+ /*
+ * 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);
+ error = xfs_initialize_perag(mp, sbp->sb_agcount, sbp->sb_dblocks,
+ &mp->m_maxagi);
+ if (error) {
+ xfs_warn(mp, "Failed post-recovery per-ag init: %d", error);
+ return error;
+ }
+ mp->m_alloc_set_aside = xfs_alloc_set_aside(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.
+ */
+int
+xlog_recover_finish(
+ struct xlog *log)
+{
+ 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);
+ return 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);
+
+ /*
+ * Now that we've recovered the log and all the intents, we can clear
+ * the log incompat feature bits in the superblock because there's no
+ * longer anything to protect. We rely on the AIL push to write out the
+ * updated superblock after everything else.
+ */
+ if (xfs_clear_incompat_log_features(log->l_mp)) {
+ error = xfs_sync_sb(log->l_mp, false);
+ if (error < 0) {
+ xfs_alert(log->l_mp,
+ "Failed to clear log incompat features on recovery");
+ return error;
+ }
+ }
+
+ 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);
+ }
+
+ return 0;
+}
+
+void
+xlog_recover_cancel(
+ struct xlog *log)
+{
+ if (xlog_recovery_needed(log))
+ xlog_recover_cancel_intents(log);
+}
+