diff options
| -rw-r--r-- | Documentation/Makefile.in | 2 | ||||
| -rw-r--r-- | Documentation/btrfs-rescue.asciidoc | 24 | ||||
| -rw-r--r-- | cmds-rescue.c | 55 |
3 files changed, 79 insertions, 2 deletions
diff --git a/Documentation/Makefile.in b/Documentation/Makefile.in index 695311dc..0c8b5ba9 100644 --- a/Documentation/Makefile.in +++ b/Documentation/Makefile.in @@ -10,7 +10,6 @@ MAN8_TXT += btrfs-image.asciidoc MAN8_TXT += btrfs-map-logical.asciidoc MAN8_TXT += btrfs-show-super.asciidoc MAN8_TXT += btrfstune.asciidoc -MAN8_TXT += btrfs-zero-log.asciidoc MAN8_TXT += fsck.btrfs.asciidoc MAN8_TXT += mkfs.btrfs.asciidoc @@ -93,6 +92,7 @@ install-man: man $(MV) $(DESTDIR)$(man5dir)/btrfs-mount.5.gz $(DESTDIR)$(man5dir)/btrfs.5.gz $(INSTALL) -m 644 $(GZ_MAN8) $(DESTDIR)$(man8dir) $(LN_S) -f btrfs-check.8.gz $(DESTDIR)$(man8dir)/btrfsck.8.gz + $(LN_S) -f btrfs-rescue.8.gz $(DESTDIR)$(man8dir)/btrfs-zero-log.8.gz uninstall: cd $(DESTDIR)$(man8dir); rm -f btrfs-check.8.gz $(GZ_MAN8) diff --git a/Documentation/btrfs-rescue.asciidoc b/Documentation/btrfs-rescue.asciidoc index e0acf091..32d8a927 100644 --- a/Documentation/btrfs-rescue.asciidoc +++ b/Documentation/btrfs-rescue.asciidoc @@ -40,6 +40,30 @@ assume an answer of 'yes' to all questions. -v:::: verbose mode. +*zero-log* <device>:: +clear out log tree + +*btrfs rescue zero-log* will remove the log tree if log tree is corrupt, which +will allow you to mount the filesystem again. + +The common case where this happens has been fixed a long time ago, +so it is unlikely that you will see this particular problem. + +One can determine whether *btrfs-zero-log* is needed according to the kernel +backtrace: +---- +? replay_one_dir_item+0xb5/0xb5 [btrfs] +? walk_log_tree+0x9c/0x19d [btrfs] +? btrfs_read_fs_root_no_radix+0x169/0x1a1 [btrfs] +? btrfs_recover_log_trees+0x195/0x29c [btrfs] +? replay_one_dir_item+0xb5/0xb5 [btrfs] +? btree_read_extent_buffer_pages+0x76/0xbc [btrfs] +? open_ctree+0xff6/0x132c [btrfs] +---- + +If the errors are like above, then *zero-log* could be used to clear +the log and the filesystem may be mounted normally again. + EXIT STATUS ----------- *btrfs rescue* returns a zero exit status if it succeeds. Non zero is diff --git a/cmds-rescue.c b/cmds-rescue.c index ebe1dda3..64193678 100644 --- a/cmds-rescue.c +++ b/cmds-rescue.c @@ -19,6 +19,9 @@ #include "kerncompat.h" #include <getopt.h> +#include "ctree.h" +#include "transaction.h" +#include "disk-io.h" #include "commands.h" #include "utils.h" @@ -149,11 +152,61 @@ int cmd_super_recover(int argc, char **argv) return ret; } +const char * const cmd_rescue_zero_log_usage[] = { + "btrfs rescue zero-log <device>", + "Clear the tree log. Usable if it's corrupted and prevents mount.", + "", + NULL +}; + +int cmd_rescue_zero_log(int argc, char **argv) +{ + struct btrfs_root *root; + struct btrfs_trans_handle *trans; + struct btrfs_super_block *sb; + char *devname; + int ret; + + if (check_argc_exact(argc, 2)) + usage(cmd_rescue_zero_log_usage); + + devname = argv[optind]; + ret = check_mounted(devname); + if (ret < 0) { + fprintf(stderr, "Could not check mount status: %s\n", strerror(-ret)); + goto out; + } else if (ret) { + fprintf(stderr, "%s is currently mounted. Aborting.\n", devname); + ret = -EBUSY; + } + + root = open_ctree(devname, 0, OPEN_CTREE_WRITES | OPEN_CTREE_PARTIAL); + if (!root) { + fprintf(stderr, "Could not open ctree\n"); + return 1; + } + + sb = root->fs_info->super_copy; + printf("Clearing log on %s, previous log_root %llu, level %u\n", + devname, + (unsigned long long)btrfs_super_log_root(sb), + (unsigned)btrfs_super_log_root_level(sb)); + trans = btrfs_start_transaction(root, 1); + btrfs_set_super_log_root(sb, 0); + btrfs_set_super_log_root_level(sb, 0); + btrfs_commit_transaction(trans, root); + close_ctree(root); + +out: + return !!ret; +} + const struct cmd_group rescue_cmd_group = { rescue_cmd_group_usage, NULL, { { "chunk-recover", cmd_chunk_recover, cmd_chunk_recover_usage, NULL, 0}, { "super-recover", cmd_super_recover, cmd_super_recover_usage, NULL, 0}, - { 0, 0, 0, 0, 0 } + { "zero-log", cmd_rescue_zero_log, cmd_rescue_zero_log_usage, NULL, 0}, + NULL_CMD_STRUCT } }; |