diff options
Diffstat (limited to 'fs/xfs/xfs_log_recover.c')
| -rw-r--r-- | fs/xfs/xfs_log_recover.c | 3517 |
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); +} + |