From 2d291b3c6bd791e0b9d89459a011dfce15982231 Mon Sep 17 00:00:00 2001 From: "Darrick J. Wong" Date: Tue, 5 May 2015 10:41:23 -0400 Subject: [PATCH] mke2fs: optionally create undo file Provide the user with an option to create an undo file so that they can roll back a failed tuning operation. Previously, one would be created if force_undo was set in the configuration file and a bunch of (undocumented) conditions were met. Signed-off-by: Darrick J. Wong Signed-off-by: Theodore Ts'o --- misc/mke2fs.8.in | 15 +++++++++++++++ misc/mke2fs.c | 25 ++++++++++++++++++++++--- 2 files changed, 37 insertions(+), 3 deletions(-) diff --git a/misc/mke2fs.8.in b/misc/mke2fs.8.in index aeb5caf6..3230f65d 100644 --- a/misc/mke2fs.8.in +++ b/misc/mke2fs.8.in @@ -117,6 +117,10 @@ mke2fs \- create an ext2/ext3/ext4 filesystem .B \-e .I errors-behavior ] +[ +.B \-z +.I undo_file +] .I device [ .I fs-size @@ -738,6 +742,17 @@ Verbose execution. Print the version number of .B mke2fs and exit. +.TP +.BI \-z " undo_file" +Before overwriting a file system block, write the old contents of the block to +an undo file. This undo file can be used with e2undo(8) to restore the old +contents of the file system should something go wrong. If the empty string is +passed as the undo_file argument, the undo file will be written to a file named +mke2fs-\fIdevice\fR.e2undo in the directory specified via the +\fIE2FSPROGS_UNDO_DIR\fR environment variable or the \fIundo_dir\fR directive +in the configuration file. + +WARNING: The undo file cannot be used to recover from a power or system crash. .SH ENVIRONMENT .TP .BI MKE2FS_SYNC diff --git a/misc/mke2fs.c b/misc/mke2fs.c index 6883103e..cd6e614f 100644 --- a/misc/mke2fs.c +++ b/misc/mke2fs.c @@ -110,6 +110,7 @@ char *journal_device; static int sync_kludge; /* Set using the MKE2FS_SYNC env. option */ char **fs_types; const char *root_dir; /* Copy files from the specified directory */ +static char *undo_file; static profile_t profile; @@ -129,7 +130,8 @@ static void usage(void) "[-M last-mounted-directory]\n\t[-O feature[,...]] " "[-r fs-revision] [-E extended-option[,...]]\n" "\t[-t fs-type] [-T usage-type ] [-U UUID] [-e errors_behavior]" - "[-jnqvDFKSV] device [blocks-count]\n"), + "[-z undo_file]\n" + "\t[-jnqvDFKSV] device [blocks-count]\n"), program_name); exit(1); } @@ -1552,7 +1554,7 @@ profile_error: } while ((c = getopt (argc, argv, - "b:ce:g:i:jl:m:no:qr:s:t:d:vC:DE:FG:I:J:KL:M:N:O:R:ST:U:V")) != EOF) { + "b:ce:g:i:jl:m:no:qr:s:t:d:vC:DE:FG:I:J:KL:M:N:O:R:ST:U:Vz:")) != EOF) { switch (c) { case 'b': blocksize = parse_num_blocks2(optarg, -1); @@ -1775,6 +1777,9 @@ profile_error: /* Print version number and exit */ show_version_only++; break; + case 'z': + undo_file = optarg; + break; default: usage(); } @@ -2493,6 +2498,19 @@ static int mke2fs_setup_tdb(const char *name, io_manager *io_ptr) char *dev_name, *tmp_name; int free_tdb_dir = 0; + /* (re)open a specific undo file */ + if (undo_file && undo_file[0] != 0) { + set_undo_io_backing_manager(*io_ptr); + *io_ptr = undo_io_manager; + retval = set_undo_io_backup_file(undo_file); + if (retval) + goto err; + printf(_("Overwriting existing filesystem; this can be undone " + "using the command:\n" + " e2undo %s %s\n\n"), undo_file, name); + return 0; + } + /* * Configuration via a conf file would be * nice @@ -2547,6 +2565,7 @@ errout: if (free_tdb_dir) free(tdb_dir); free(tdb_file); +err: com_err(program_name, retval, "%s", _("while trying to setup undo file\n")); return retval; @@ -2718,7 +2737,7 @@ int main (int argc, char *argv[]) #endif io_ptr = unix_io_manager; - if (should_do_undo(device_name)) { + if (undo_file != NULL || should_do_undo(device_name)) { retval = mke2fs_setup_tdb(device_name, &io_ptr); if (retval) exit(1); -- 2.11.0