On Jan 1, 2019, at 2:07 PM, Artem Blagodarenko <artem.blagodarenko@xxxxxxxxx> wrote: > > e2image and e2fsck automatically try to open some backup superblocks, > if only blocksize is set or passed superblock can't be opened. > Try few backup superblocks (e.g. {1, 3, 5, 7, 9} * blocksize * 8). > > This code is moved to lib/support/. > > Signed-off-by: Artem Blagodarenko <c17828@xxxxxxxx> Reviewed-by: Andreas Dilger <adilger@xxxxxxxxx> > --- > e2fsck/e2fsck.h | 2 - > e2fsck/message.c | 3 +- > e2fsck/unix.c | 14 +++-- > e2fsck/util.c | 73 ------------------------- > lib/support/Makefile.in | 8 ++- > lib/support/sb_backup.c | 140 ++++++++++++++++++++++++++++++++++++++++++++++++ > lib/support/sb_backup.h | 20 +++++++ > misc/e2image.c | 7 +++ > 8 files changed, 185 insertions(+), 82 deletions(-) > > diff --git a/e2fsck/e2fsck.h b/e2fsck/e2fsck.h > index 1c7a67cb..8576ef24 100644 > --- a/e2fsck/e2fsck.h > +++ b/e2fsck/e2fsck.h > @@ -633,8 +633,6 @@ extern void e2fsck_write_inode_full(e2fsck_t ctx, unsigned long ino, > #ifdef MTRACE > extern void mtrace_print(char *mesg); > #endif > -extern blk64_t get_backup_sb(e2fsck_t ctx, ext2_filsys fs, > - const char *name, io_manager manager); > extern int ext2_file_type(unsigned int mode); > extern int write_all(int fd, char *buf, size_t count); > void dump_mmp_msg(struct mmp_struct *mmp, const char *fmt, ...) > diff --git a/e2fsck/message.c b/e2fsck/message.c > index 727f71d5..ffb40730 100644 > --- a/e2fsck/message.c > +++ b/e2fsck/message.c > @@ -465,7 +465,8 @@ static _INLINE_ void expand_percent_expression(FILE *f, ext2_filsys fs, > fprintf(f, "%*lld", width, (long long) ctx->blkcount); > break; > case 'S': > - fprintf(f, "%llu", get_backup_sb(NULL, fs, NULL, NULL)); > + fprintf(f, "%llu", get_first_backup_sb(NULL, NULL, fs, > + NULL, NULL)); > break; > case 's': > fprintf(f, "%*s", width, ctx->str ? ctx->str : "NULL"); > diff --git a/e2fsck/unix.c b/e2fsck/unix.c > index ddcf52a4..4ffc039e 100644 > --- a/e2fsck/unix.c > +++ b/e2fsck/unix.c > @@ -1489,11 +1489,17 @@ restart: > retval ? _("Superblock invalid,") : > _("Group descriptors look bad...")); > orig_superblock = ctx->superblock; > - get_backup_sb(ctx, fs, ctx->filesystem_name, io_ptr); > - if (fs) > - ext2fs_close_free(&fs); > orig_retval = retval; > - retval = try_open_fs(ctx, flags, io_ptr, &fs); > + retval = try_backups(ctx->filesystem_name, > + ctx->io_options, > + flags, &ctx->superblock, > + &ctx->blocksize, io_ptr, &fs); > + if (retval == 0) { > + fs->priv_data = ctx; > + e2fsck_set_bitmap_type(fs, > + EXT2FS_BMAP64_RBTREE, > + "default", NULL); > + } > if ((orig_retval == 0) && retval != 0) { > if (fs) > ext2fs_close_free(&fs); > diff --git a/e2fsck/util.c b/e2fsck/util.c > index db6a1cc1..e2caf3a2 100644 > --- a/e2fsck/util.c > +++ b/e2fsck/util.c > @@ -549,79 +549,6 @@ void mtrace_print(char *mesg) > } > #endif > > -blk64_t get_backup_sb(e2fsck_t ctx, ext2_filsys fs, const char *name, > - io_manager manager) > -{ > - struct ext2_super_block *sb; > - io_channel io = NULL; > - void *buf = NULL; > - int blocksize; > - blk64_t superblock, ret_sb = 8193; > - > - if (fs && fs->super) { > - ret_sb = (fs->super->s_blocks_per_group + > - fs->super->s_first_data_block); > - if (ctx) { > - ctx->superblock = ret_sb; > - ctx->blocksize = fs->blocksize; > - } > - return ret_sb; > - } > - > - if (ctx) { > - if (ctx->blocksize) { > - ret_sb = ctx->blocksize * 8; > - if (ctx->blocksize == 1024) > - ret_sb++; > - ctx->superblock = ret_sb; > - return ret_sb; > - } > - ctx->superblock = ret_sb; > - ctx->blocksize = 1024; > - } > - > - if (!name || !manager) > - goto cleanup; > - > - if (manager->open(name, 0, &io) != 0) > - goto cleanup; > - > - if (ext2fs_get_mem(SUPERBLOCK_SIZE, &buf)) > - goto cleanup; > - sb = (struct ext2_super_block *) buf; > - > - for (blocksize = EXT2_MIN_BLOCK_SIZE; > - blocksize <= EXT2_MAX_BLOCK_SIZE ; blocksize *= 2) { > - superblock = blocksize*8; > - if (blocksize == 1024) > - superblock++; > - io_channel_set_blksize(io, blocksize); > - if (io_channel_read_blk64(io, superblock, > - -SUPERBLOCK_SIZE, buf)) > - continue; > -#ifdef WORDS_BIGENDIAN > - if (sb->s_magic == ext2fs_swab16(EXT2_SUPER_MAGIC)) > - ext2fs_swap_super(sb); > -#endif > - if ((sb->s_magic == EXT2_SUPER_MAGIC) && > - (EXT2_BLOCK_SIZE(sb) == blocksize)) { > - ret_sb = superblock; > - if (ctx) { > - ctx->superblock = superblock; > - ctx->blocksize = blocksize; > - } > - break; > - } > - } > - > -cleanup: > - if (io) > - io_channel_close(io); > - if (buf) > - ext2fs_free_mem(&buf); > - return (ret_sb); > -} > - > /* > * Given a mode, return the ext2 file type > */ > diff --git a/lib/support/Makefile.in b/lib/support/Makefile.in > index 1d278642..03fdf555 100644 > --- a/lib/support/Makefile.in > +++ b/lib/support/Makefile.in > @@ -22,7 +22,8 @@ OBJS= cstring.o \ > quotaio.o \ > quotaio_v2.o \ > quotaio_tree.o \ > - dict.o > + dict.o \ > + sb_backup.o > > SRCS= $(srcdir)/argv_parse.c \ > $(srcdir)/cstring.c \ > @@ -35,7 +36,8 @@ SRCS= $(srcdir)/argv_parse.c \ > $(srcdir)/quotaio.c \ > $(srcdir)/quotaio_tree.c \ > $(srcdir)/quotaio_v2.c \ > - $(srcdir)/dict.c > + $(srcdir)/dict.c \ > + $(srcdir)/sb_backup.c > > LIBRARY= libsupport > LIBDIR= support > @@ -168,3 +170,5 @@ quotaio_v2.o: $(srcdir)/quotaio_v2.c $(top_builddir)/lib/config.h \ > $(srcdir)/quotaio_tree.h > dict.o: $(srcdir)/dict.c $(top_builddir)/lib/config.h \ > $(top_builddir)/lib/dirpaths.h $(srcdir)/dict.h > +sb_backup.o: $(srcdir)/sb_backup.c $(top_builddir)/lib/config.h \ > + $(srcdir)/sb_backup.h > diff --git a/lib/support/sb_backup.c b/lib/support/sb_backup.c > new file mode 100644 > index 00000000..cfa671e5 > --- /dev/null > +++ b/lib/support/sb_backup.c > @@ -0,0 +1,140 @@ > +/* > + * sb_backup.c -- helper functions for getting backup superblocks > + * > + * %Begin-Header% > + * This file may be redistributed under the terms of the GNU Library > + * General Public License, version 2. > + * %End-Header% > + */ > + > + > +#include "config.h" > +#include <stdio.h> > +#include <string.h> > + > +#include "ext2fs/ext2_fs.h" > +#include "ext2fs/ext2fs.h" > + > +blk64_t get_first_backup_sb(blk64_t *superblock, unsigned int *block_size, > + ext2_filsys fs, const char *name, > + io_manager manager) > +{ > + struct ext2_super_block *sb; > + io_channel io = NULL; > + void *buf = NULL; > + int try_blocksize; > + blk64_t try_superblock, ret_sb = 8193; > + > + /* superblock and block_size can be NULL if fs->super is passed */ > + if (fs && fs->super) { > + ret_sb = fs->super->s_blocks_per_group + > + fs->super->s_first_data_block; > + if (superblock) > + *superblock = ret_sb; > + if (block_size) > + *block_size = fs->blocksize; > + return ret_sb; > + } > + > + if (*block_size) { > + ret_sb = *block_size * 8; > + if (*block_size == 1024) > + ret_sb++; > + *superblock = ret_sb; > + return ret_sb; > + } > + > + *superblock = ret_sb; > + *block_size = 1024; > + > + if (!name || !manager) > + goto cleanup; > + > + if (manager->open(name, 0, &io) != 0) > + goto cleanup; > + > + if (ext2fs_get_mem(SUPERBLOCK_SIZE, &buf)) > + goto cleanup; > + sb = (struct ext2_super_block *) buf; > + > + for (try_blocksize = EXT2_MIN_BLOCK_SIZE; > + try_blocksize <= EXT2_MAX_BLOCK_SIZE ; try_blocksize *= 2) { > + try_superblock = try_blocksize*8; > + if (try_blocksize == 1024) > + try_superblock++; > + io_channel_set_blksize(io, try_blocksize); > + if (io_channel_read_blk64(io, try_superblock, > + -SUPERBLOCK_SIZE, buf)) > + continue; > +#ifdef WORDS_BIGENDIAN > + if (sb->s_magic == ext2fs_swab16(EXT2_SUPER_MAGIC)) > + ext2fs_swap_super(sb); > +#endif > + if ((sb->s_magic == EXT2_SUPER_MAGIC) && > + (EXT2_BLOCK_SIZE(sb) == try_blocksize)) { > + ret_sb = try_superblock; > + *superblock = try_superblock; > + *block_size = try_blocksize; > + break; > + } > + } > + > +cleanup: > + if (io) > + io_channel_close(io); > + if (buf) > + ext2fs_free_mem(&buf); > + return ret_sb; > +} > + > +errcode_t try_backups(const char *name, const char *io_options, > + int flags, blk64_t *superblock, > + unsigned int *block_size, io_manager manager, > + ext2_filsys *ret_fs) > +{ > + errcode_t retval, retval2; > + blk64_t try_block_number; > + unsigned int i; > + > + /* > + * Get first superblock location based on heuristic. > + * Blocksize is also returned and used to find next > + * superblock copy location. > + */ > + try_block_number = get_first_backup_sb(superblock, block_size, > + *ret_fs, name, manager); > + retval = ext2fs_open2(name, io_options, flags, try_block_number, > + *block_size, manager, ret_fs); > + if (!retval) > + return 0; > + > + /* > + * Try 3d, 5th, 7th, 9th superblock copy > + */ > + for (i = 3; i <= 9; i += 2) { > + try_block_number = (i * (*block_size) * 8); > + if (*block_size == 1024) > + try_block_number++; > + if (*ret_fs) { > + ext2fs_free(*ret_fs); > + *ret_fs = NULL; > + } > + retval2 = ext2fs_open2(name, io_options, flags, > + try_block_number, *block_size, manager, > + ret_fs); > + /* > + * Partition is too small to have this superblock copy. > + * Return previous reading return code > + */ > + if (retval2 == EXT2_ET_SHORT_READ) > + break; > + > + retval = retval2; > + if (!retval) { > + *superblock = try_block_number; > + break; > + } > + } > + > + return retval; > +} > diff --git a/lib/support/sb_backup.h b/lib/support/sb_backup.h > new file mode 100644 > index 00000000..1e18e37c > --- /dev/null > +++ b/lib/support/sb_backup.h > @@ -0,0 +1,20 @@ > +/* > + * sb_backup.h -- helper functions for getting backup superblocks > + * > + * %Begin-Header% > + * This file may be redistributed under the terms of the GNU Library > + * General Public License, version 2. > + * %End-Header% > + */ > + > +#include "ext2fs/ext2_fs.h" > +#include "ext2fs/ext2fs.h" > + > +blk64_t get_first_backup_sb(blk64_t *superblock, unsigned int *block_size, > + ext2_filsys fs, const char *name, > + io_manager manager); > + > +errcode_t try_backups(const char *name, const char *io_options, > + int flags, blk64_t *superblock, > + unsigned int *block_size, io_manager manager, > + ext2_filsys *ret_fs); > diff --git a/misc/e2image.c b/misc/e2image.c > index 3c881fee..786282ec 100644 > --- a/misc/e2image.c > +++ b/misc/e2image.c > @@ -1623,6 +1623,13 @@ int main (int argc, char ** argv) > sprintf(offset_opt, "offset=%llu", source_offset); > retval = ext2fs_open2(device_name, offset_opt, open_flag, > superblock, blocksize, unix_io_manager, &fs); > + if (retval & (superblock | blocksize)) { > + printf(_("Try backups in other location.\n")); > + retval = try_backups(device_name, offset_opt, open_flag, > + &superblock, &blocksize, > + unix_io_manager, &fs); > + printf(_("Use superblock %i.\n"), superblock); > + } > if (retval) { > com_err (program_name, retval, _("while trying to open %s"), > device_name); > -- > 2.14.3 > Cheers, Andreas
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