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diff --git a/upstream/debian-bookworm/man8/btrfs-rescue.8 b/upstream/debian-bookworm/man8/btrfs-rescue.8 new file mode 100644 index 00000000..aa8d4410 --- /dev/null +++ b/upstream/debian-bookworm/man8/btrfs-rescue.8 @@ -0,0 +1,181 @@ +.\" Man page generated from reStructuredText. +. +. +.nr rst2man-indent-level 0 +. +.de1 rstReportMargin +\\$1 \\n[an-margin] +level \\n[rst2man-indent-level] +level margin: \\n[rst2man-indent\\n[rst2man-indent-level]] +- +\\n[rst2man-indent0] +\\n[rst2man-indent1] +\\n[rst2man-indent2] +.. +.de1 INDENT +.\" .rstReportMargin pre: +. RS \\$1 +. nr rst2man-indent\\n[rst2man-indent-level] \\n[an-margin] +. nr rst2man-indent-level +1 +.\" .rstReportMargin post: +.. +.de UNINDENT +. RE +.\" indent \\n[an-margin] +.\" old: \\n[rst2man-indent\\n[rst2man-indent-level]] +.nr rst2man-indent-level -1 +.\" new: \\n[rst2man-indent\\n[rst2man-indent-level]] +.in \\n[rst2man-indent\\n[rst2man-indent-level]]u +.. +.TH "BTRFS-RESCUE" "8" "Feb 28, 2023" "6.2" "BTRFS" +.SH NAME +btrfs-rescue \- recover a damaged btrfs filesystem +.SH SYNOPSIS +.sp +\fBbtrfs rescue\fP <subcommand> <args> +.SH DESCRIPTION +.sp +\fBbtrfs rescue\fP is used to try to recover a damaged btrfs filesystem. +.SH SUBCOMMAND +.INDENT 0.0 +.TP +.B chunk\-recover [options] <device> +Recover the chunk tree by scanning the devices +.sp +\fBOptions\fP +.INDENT 7.0 +.TP +.B \-y +assume an answer of \fIyes\fP to all questions. +.TP +.B \-h +help. +.TP +.B \-v +(deprecated) alias for global \fI\-v\fP option +.UNINDENT +.UNINDENT +.sp +\fBNOTE:\fP +.INDENT 0.0 +.INDENT 3.5 +Since \fBchunk\-recover\fP will scan the whole device, it will be very +slow especially executed on a large device. +.UNINDENT +.UNINDENT +.INDENT 0.0 +.TP +.B fix\-device\-size <device> +fix device size and super block total bytes values that are do not match +.sp +Kernel 4.11 starts to check the device size more strictly and this might +mismatch the stored value of total bytes. See the exact error message below. +Newer kernel will refuse to mount the filesystem where the values do not match. +This error is not fatal and can be fixed. This command will fix the device +size values if possible. +.INDENT 7.0 +.INDENT 3.5 +.sp +.nf +.ft C +BTRFS error (device sdb): super_total_bytes 92017859088384 mismatch with fs_devices total_rw_bytes 92017859094528 +.ft P +.fi +.UNINDENT +.UNINDENT +.sp +The mismatch may also exhibit as a kernel warning: +.INDENT 7.0 +.INDENT 3.5 +.sp +.nf +.ft C +WARNING: CPU: 3 PID: 439 at fs/btrfs/ctree.h:1559 btrfs_update_device+0x1c5/0x1d0 [btrfs] +.ft P +.fi +.UNINDENT +.UNINDENT +.TP +.B clear\-uuid\-tree <device> +Clear UUID tree, so that kernel can re\-generate it at next read\-write +mount. +.sp +Since kernel v4.16 there are more sanity check performed, and sometimes +non\-critical trees like UUID tree can cause problems and reject the mount. +In such case, clearing UUID tree may make the filesystem to be mountable again +without much risk as it\(aqs built from other trees. +.TP +.B super\-recover [options] <device> +Recover bad superblocks from good copies. +.sp +\fBOptions\fP +.INDENT 7.0 +.TP +.B \-y +assume an answer of \fIyes\fP to all questions. +.TP +.B \-v +(deprecated) alias for global \fI\-v\fP option +.UNINDENT +.TP +.B zero\-log <device> +clear the filesystem log tree +.sp +This command will clear the filesystem log tree. This may fix a specific +set of problem when the filesystem mount fails due to the log replay. See below +for sample stack traces that may show up in system log. +.sp +The common case where this happens was fixed a long time ago, +so it is unlikely that you will see this particular problem, but the command is +kept around. +.sp +\fBNOTE:\fP +.INDENT 7.0 +.INDENT 3.5 +Clearing the log may lead to loss of changes that were made +since the last transaction commit. This may be up to 30 seconds +(default commit period) or less if the commit was implied by +other filesystem activity. +.UNINDENT +.UNINDENT +.sp +One can determine whether \fBzero\-log\fP is needed according to the kernel +backtrace: +.INDENT 7.0 +.INDENT 3.5 +.sp +.nf +.ft C +? 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] +.ft P +.fi +.UNINDENT +.UNINDENT +.sp +If the errors are like above, then \fBzero\-log\fP should be used to clear +the log and the filesystem may be mounted normally again. The keywords to look +for are \(aqopen_ctree\(aq which says that it\(aqs during mount and function names +that contain \fIreplay\fP, \fIrecover\fP or \fIlog_tree\fP\&. +.UNINDENT +.SH EXIT STATUS +.sp +\fBbtrfs rescue\fP returns a zero exit status if it succeeds. Non zero is +returned in case of failure. +.SH AVAILABILITY +.sp +\fBbtrfs\fP is part of btrfs\-progs. Please refer to the documentation at +\fI\%https://btrfs.readthedocs.io\fP or wiki \fI\%http://btrfs.wiki.kernel.org\fP for further +information. +.SH SEE ALSO +.sp +\fI\%btrfs\-check(8)\fP, +\fI\%btrfs\-scrub(8)\fP, +\fI\%mkfs.btrfs(8)\fP +.\" Generated by docutils manpage writer. +. |