linux-ext4 - Re: flashing large eMMC partitions with ext4

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date:	Mon, 1 Aug 2011 22:44:01 +0300
From:	Amir Goldstein <amir73il@...il.com>
To:	Round Robinjp <roundrobinjp@...oo.co.jp>
Cc:	Andreas Dilger <aedilger@...il.com>, "Ted Ts'o" <tytso@....edu>,
	"linux-ext4@...r.kernel.org" <linux-ext4@...r.kernel.org>
Subject: Re: flashing large eMMC partitions with ext4

On Mon, Aug 1, 2011 at 8:43 PM, Round Robinjp <roundrobinjp@...oo.co.jp> wrote:
>> I meant using a newer version of resize2fs (which you do not have),
>
> I have now corrected this and other mistakes.
> But when I mount the image after finally extending
> to 4G, the df still shows the size as 1G.
> Am I still doing something wrong?

yes, a few things :-)

>
> Full log below:
>
> -----------------------------------------
> -----------------------------------------
> -----------------------------------------
> $ dd if=/dev/zero of=a.img bs=4K count=256K
> 262144+0 records in
> 262144+0 records out
> 1073741824 bytes (1.1 GB) copied, 4.09006 s, 263 MB/s
>

create the initial a.img 4G and specify 1G to mkfs.
so the loop device size is 4G and you can online resize the fs to 4G.

> $ mkfs.ext4 -O ^has_journal,flex_bg -G 32 -E resize=4G a.img
> mke2fs 1.42-WIP (02-Jul-2011)
> a.img is not a block special device.
> Proceed anyway? (y,n) y
> Filesystem label=
> OS type: Linux
> Block size=4096 (log=2)
> Fragment size=4096 (log=2)
> Stride=0 blocks, Stripe width=0 blocks
> 65536 inodes, 262144 blocks
> 13107 blocks (5.00%) reserved for the super user
> First data block=0
> Maximum filesystem blocks=268435456
> 8 block groups
> 32768 blocks per group, 32768 fragments per group
> 8192 inodes per group
> Superblock backups stored on blocks:
>        32768, 98304, 163840, 229376
>
> Allocating group tables: done
> Writing inode tables: done
> Writing superblocks and filesystem accounting information: done
>
> This filesystem will be automatically checked every 0 mounts or
> 0 days, whichever comes first.  Use tune2fs -c or -i to override.
>
> $ sudo mount -t ext4 -o loop a.img /mnt/
> $ du -sh /usr/src/
> 92M     /usr/src/
> $ cp -a /usr/src/* /mnt/
>

you should not run fsck on a mounted fs.
this is not good.
if you run fsck /dev/loop0 you will get an error.
if you want to check the fs, umount it first.

> $ e2fsck -f a.img
> e2fsck 1.42-WIP (02-Jul-2011)
> Pass 1: Checking inodes, blocks, and sizes
> Pass 2: Checking directory structure
> Pass 3: Checking directory connectivity
> Pass 4: Checking reference counts
> Pass 5: Checking group summary information
> Free blocks count wrong (242859, counted=237788).
> Fix<y>? yes
>
> Free inodes count wrong (55821, counted=52249).
> Fix<y>? yes
>
>
> a.img: ***** FILE SYSTEM WAS MODIFIED *****
> a.img: 13287/65536 files (0.0% non-contiguous), 24356/262144 blocks
>
> $ resize2fs a.img 4G

resize2fs /dev/loop0

> resize2fs 1.42-WIP (02-Jul-2011)
> Please run 'e2fsck -f a.img' first.
>
> $ e2fsck -f a.img
> e2fsck 1.42-WIP (02-Jul-2011)
> Pass 1: Checking inodes, blocks, and sizes
> Pass 2: Checking directory structure
> Pass 3: Checking directory connectivity
> Pass 4: Checking reference counts
> Pass 5: Checking group summary information
> a.img: 20864/65536 files (0.0% non-contiguous), 27067/262144 blocks
>
> $ resize2fs a.img 4G
> resize2fs 1.42-WIP (02-Jul-2011)
> Resizing the filesystem on a.img to 1048576 (4k) blocks.
> The filesystem on a.img is now 1048576 blocks long.
>
> $ sudo tune2fs -O has_journal /dev/loop0
> tune2fs 1.42-WIP (02-Jul-2011)
> Creating journal inode: done
> This filesystem will be automatically checked every 20 mounts or
> 0 days, whichever comes first.  Use tune2fs -c or -i to override.
>
> $ sudo umount /mnt
>
> $ dumpe2fs a.img
> dumpe2fs 1.42-WIP (02-Jul-2011)
> Filesystem volume name:   <none>
> Last mounted on:          /mnt
> Filesystem UUID:          4f2361c3-2755-4a6a-bf28-dd7e1a4dd772
> Filesystem magic number:  0xEF53
> Filesystem revision #:    1 (dynamic)
> Filesystem features:      has_journal ext_attr resize_inode dir_index filetype extent flex_bg sparse_super large_file huge_file uninit_bg dir_nlink extra_isize
> Filesystem flags:         signed_directory_hash
> Default mount options:    user_xattr acl
> Filesystem state:         clean
> Errors behavior:          Continue
> Filesystem OS type:       Linux
> Inode count:              65536
> Block count:              262144

if you do everything right you should have 1048576 blocks after resize.

> Reserved block count:     13107
> Free blocks:              226191
> Free inodes:              44671
> First block:              0
> Block size:               4096
> Fragment size:            4096
> Reserved GDT blocks:      63
> Blocks per group:         32768
> Fragments per group:      32768
> Inodes per group:         8192
> Inode blocks per group:   512
> Flex block group size:    32
> Filesystem created:       Tue Aug  2 02:29:45 2011
> Last mount time:          Tue Aug  2 02:29:50 2011
> Last write time:          Tue Aug  2 02:31:01 2011
> Mount count:              1
> Maximum mount count:      20
> Last checked:             Tue Aug  2 02:29:45 2011
> Check interval:           0 (<none>)
> Lifetime writes:          406 kB
> Reserved blocks uid:      0 (user root)
> Reserved blocks gid:      0 (group root)
> First inode:              11
> Inode size:               256
> Required extra isize:     28
> Desired extra isize:      28
> Journal inode:            20500
> Default directory hash:   half_md4
> Directory Hash Seed:      a42d0c4e-0207-4fd4-94e7-b71bc107ae90
> Journal features:         (none)
> Journal size:             32M
> Journal length:           8192
> Journal sequence:         0x00000001
> Journal start:            0
>
>
> Group 0: (Blocks 0-32767) [ITABLE_ZEROED]
>  Checksum 0x3fe2, unused inodes 0
>  Primary superblock at 0, Group descriptors at 1-1
>  Reserved GDT blocks at 2-64
>  Block bitmap at 65 (+65), Inode bitmap at 97 (+97)
>  Inode table at 129-640 (+129)
>  24746 free blocks, 0 free inodes, 3 directories
>  Free blocks: 20358-32767
>  Free inodes:
> Group 1: (Blocks 32768-65535) [ITABLE_ZEROED]
>  Checksum 0x1361, unused inodes 0
>  Backup superblock at 32768, Group descriptors at 32769-32769
>  Reserved GDT blocks at 32770-32832
>  Block bitmap at 66 (bg #0 + 66), Inode bitmap at 98 (bg #0 + 98)
>  Inode table at 641-1152 (bg #0 + 641)
>  9128 free blocks, 0 free inodes, 975 directories
>  Free blocks: 49152-57343, 60376-60383, 60512-61439
>  Free inodes:
> Group 2: (Blocks 65536-98303) [ITABLE_ZEROED]
>  Checksum 0x3bb7, unused inodes 4076
>  Block bitmap at 67 (bg #0 + 67), Inode bitmap at 99 (bg #0 + 99)
>  Inode table at 1153-1664 (bg #0 + 1153)
>  28672 free blocks, 4076 free inodes, 2302 directories, 4076 unused inodes
>  Free blocks: 69632-98303
>  Free inodes: 20501-24576
> Group 3: (Blocks 98304-131071) [ITABLE_ZEROED]
>  Checksum 0x372b, unused inodes 7865
>  Backup superblock at 98304, Group descriptors at 98305-98305
>  Reserved GDT blocks at 98306-98368
>  Block bitmap at 68 (bg #0 + 68), Inode bitmap at 100 (bg #0 + 100)
>  Inode table at 1665-2176 (bg #0 + 1665)
>  32703 free blocks, 7865 free inodes, 327 directories, 7865 unused inodes
>  Free blocks: 98369-131071
>  Free inodes: 24904-32768
> Group 4: (Blocks 131072-163839) [ITABLE_ZEROED]
>  Checksum 0x4c7a, unused inodes 8154
>  Block bitmap at 69 (bg #0 + 69), Inode bitmap at 101 (bg #0 + 101)
>  Inode table at 2177-2688 (bg #0 + 2177)
>  32768 free blocks, 8154 free inodes, 38 directories, 8154 unused inodes
>  Free blocks: 131072-163839
>  Free inodes: 32807-40960
> Group 5: (Blocks 163840-196607) [INODE_UNINIT, ITABLE_ZEROED]
>  Checksum 0xbd51, unused inodes 8192
>  Backup superblock at 163840, Group descriptors at 163841-163841
>  Reserved GDT blocks at 163842-163904
>  Block bitmap at 70 (bg #0 + 70), Inode bitmap at 102 (bg #0 + 102)
>  Inode table at 2689-3200 (bg #0 + 2689)
>  32703 free blocks, 8192 free inodes, 0 directories, 8192 unused inodes
>  Free blocks: 163905-196607
>  Free inodes: 40961-49152
> Group 6: (Blocks 196608-229375) [INODE_UNINIT, BLOCK_UNINIT, ITABLE_ZEROED]
>  Checksum 0xf453, unused inodes 8192
>  Block bitmap at 71 (bg #0 + 71), Inode bitmap at 103 (bg #0 + 103)
>  Inode table at 3201-3712 (bg #0 + 3201)
>  32768 free blocks, 8192 free inodes, 0 directories, 8192 unused inodes
>  Free blocks: 196608-229375
>  Free inodes: 49153-57344
> Group 7: (Blocks 229376-262143) [INODE_UNINIT, ITABLE_ZEROED]
>  Checksum 0xfcc2, unused inodes 8192
>  Backup superblock at 229376, Group descriptors at 229377-229377
>  Reserved GDT blocks at 229378-229440
>  Block bitmap at 72 (bg #0 + 72), Inode bitmap at 104 (bg #0 + 104)
>  Inode table at 3713-4224 (bg #0 + 3713)
>  32703 free blocks, 8192 free inodes, 0 directories, 8192 unused inodes
>  Free blocks: 229441-262143
>  Free inodes: 57345-65536
>
> $ truncate -s 1G a.img
>
> $ e2fsck -f a.img

don't try to 'fix' the fs before truncate -s 4G.
you can run fsck -nf if you want to see how the fs looks now.

> e2fsck 1.42-WIP (02-Jul-2011)
> Backing up journal inode block information.
>
> Moving journal from /.journal to hidden inode.
>
> Pass 1: Checking inodes, blocks, and sizes
> Inode 7 has illegal block(s).  Clear<y>? yes
>
> Illegal block #2064 (294914) in inode 7.  CLEARED.
> Illegal block #2065 (819202) in inode 7.  CLEARED.
> Illegal block #2066 (884738) in inode 7.  CLEARED.
> Illegal block #3088 (294915) in inode 7.  CLEARED.
> Illegal block #3089 (819203) in inode 7.  CLEARED.
> Illegal block #3090 (884739) in inode 7.  CLEARED.
> Illegal block #4112 (294916) in inode 7.  CLEARED.
> Illegal block #4113 (819204) in inode 7.  CLEARED.
> Illegal block #4114 (884740) in inode 7.  CLEARED.
> Illegal block #5136 (294917) in inode 7.  CLEARED.
> Illegal block #5137 (819205) in inode 7.  CLEARED.
> Too many illegal blocks in inode 7.
> Clear inode<y>? yes
>
> Restarting e2fsck from the beginning...
> Resize inode not valid.  Recreate<y>? yes
>
> Pass 1: Checking inodes, blocks, and sizes
> Pass 2: Checking directory structure
> Pass 3: Checking directory connectivity
> Pass 4: Checking reference counts
> Pass 5: Checking group summary information
> Block bitmap differences:  -(8022--20357)
> Fix<y>? yes
>
> Free blocks count wrong for group #0 (24745, counted=24746).
> Fix<y>? yes
>
> Free blocks count wrong (226190, counted=226191).
> Fix<y>? yes
>
>
> a.img: ***** FILE SYSTEM WAS MODIFIED *****
> a.img: 20864/65536 files (0.0% non-contiguous), 35953/262144 blocks
> $
>
> $ dumpe2fs a.img
> dumpe2fs 1.42-WIP (02-Jul-2011)
> Filesystem volume name:   <none>
> Last mounted on:          /mnt
> Filesystem UUID:          4f2361c3-2755-4a6a-bf28-dd7e1a4dd772
> Filesystem magic number:  0xEF53
> Filesystem revision #:    1 (dynamic)
> Filesystem features:      has_journal ext_attr resize_inode dir_index filetype extent flex_bg sparse_super large_file huge_file uninit_bg dir_nlink extra_isize
> Filesystem flags:         signed_directory_hash
> Default mount options:    user_xattr acl
> Filesystem state:         clean
> Errors behavior:          Continue
> Filesystem OS type:       Linux
> Inode count:              65536
> Block count:              262144
> Reserved block count:     13107
> Free blocks:              226191
> Free inodes:              44672
> First block:              0
> Block size:               4096
> Fragment size:            4096
> Reserved GDT blocks:      63
> Blocks per group:         32768
> Fragments per group:      32768
> Inodes per group:         8192
> Inode blocks per group:   512
> Flex block group size:    32
> Filesystem created:       Tue Aug  2 02:29:45 2011
> Last mount time:          Tue Aug  2 02:29:50 2011
> Last write time:          Tue Aug  2 02:32:29 2011
> Mount count:              0
> Maximum mount count:      20
> Last checked:             Tue Aug  2 02:32:29 2011
> Check interval:           0 (<none>)
> Lifetime writes:          742 kB
> Reserved blocks uid:      0 (user root)
> Reserved blocks gid:      0 (group root)
> First inode:              11
> Inode size:               256
> Required extra isize:     28
> Desired extra isize:      28
> Journal inode:            8
> Default directory hash:   half_md4
> Directory Hash Seed:      a42d0c4e-0207-4fd4-94e7-b71bc107ae90
> Journal backup:           inode blocks
> Journal features:         (none)
> Journal size:             32M
> Journal length:           8192
> Journal sequence:         0x00000001
> Journal start:            0
>
>
> Group 0: (Blocks 0-32767) [ITABLE_ZEROED]
>  Checksum 0x3fe2, unused inodes 0
>  Primary superblock at 0, Group descriptors at 1-1
>  Reserved GDT blocks at 2-64
>  Block bitmap at 65 (+65), Inode bitmap at 97 (+97)
>  Inode table at 129-640 (+129)
>  24746 free blocks, 0 free inodes, 3 directories
>  Free blocks: 8022-32767
>  Free inodes:
> Group 1: (Blocks 32768-65535) [ITABLE_ZEROED]
>  Checksum 0x1361, unused inodes 0
>  Backup superblock at 32768, Group descriptors at 32769-32769
>  Reserved GDT blocks at 32770-32832
>  Block bitmap at 66 (bg #0 + 66), Inode bitmap at 98 (bg #0 + 98)
>  Inode table at 641-1152 (bg #0 + 641)
>  9128 free blocks, 0 free inodes, 975 directories
>  Free blocks: 49152-57343, 60376-60383, 60512-61439
>  Free inodes:
> Group 2: (Blocks 65536-98303) [ITABLE_ZEROED]
>  Checksum 0x3b77, unused inodes 4077
>  Block bitmap at 67 (bg #0 + 67), Inode bitmap at 99 (bg #0 + 99)
>  Inode table at 1153-1664 (bg #0 + 1153)
>  28672 free blocks, 4077 free inodes, 2302 directories, 4077 unused inodes
>  Free blocks: 69632-98303
>  Free inodes: 20500-24576
> Group 3: (Blocks 98304-131071) [ITABLE_ZEROED]
>  Checksum 0x372b, unused inodes 7865
>  Backup superblock at 98304, Group descriptors at 98305-98305
>  Reserved GDT blocks at 98306-98368
>  Block bitmap at 68 (bg #0 + 68), Inode bitmap at 100 (bg #0 + 100)
>  Inode table at 1665-2176 (bg #0 + 1665)
>  32703 free blocks, 7865 free inodes, 327 directories, 7865 unused inodes
>  Free blocks: 98369-131071
>  Free inodes: 24904-32768
> Group 4: (Blocks 131072-163839) [ITABLE_ZEROED]
>  Checksum 0x4c7a, unused inodes 8154
>  Block bitmap at 69 (bg #0 + 69), Inode bitmap at 101 (bg #0 + 101)
>  Inode table at 2177-2688 (bg #0 + 2177)
>  32768 free blocks, 8154 free inodes, 38 directories, 8154 unused inodes
>  Free blocks: 131072-163839
>  Free inodes: 32807-40960
> Group 5: (Blocks 163840-196607) [INODE_UNINIT, ITABLE_ZEROED]
>  Checksum 0xbd51, unused inodes 8192
>  Backup superblock at 163840, Group descriptors at 163841-163841
>  Reserved GDT blocks at 163842-163904
>  Block bitmap at 70 (bg #0 + 70), Inode bitmap at 102 (bg #0 + 102)
>  Inode table at 2689-3200 (bg #0 + 2689)
>  32703 free blocks, 8192 free inodes, 0 directories, 8192 unused inodes
>  Free blocks: 163905-196607
>  Free inodes: 40961-49152
> Group 6: (Blocks 196608-229375) [INODE_UNINIT, BLOCK_UNINIT, ITABLE_ZEROED]
>  Checksum 0xf453, unused inodes 8192
>  Block bitmap at 71 (bg #0 + 71), Inode bitmap at 103 (bg #0 + 103)
>  Inode table at 3201-3712 (bg #0 + 3201)
>  32768 free blocks, 8192 free inodes, 0 directories, 8192 unused inodes
>  Free blocks: 196608-229375
>  Free inodes: 49153-57344
> Group 7: (Blocks 229376-262143) [INODE_UNINIT, ITABLE_ZEROED]
>  Checksum 0xfcc2, unused inodes 8192
>  Backup superblock at 229376, Group descriptors at 229377-229377
>  Reserved GDT blocks at 229378-229440
>  Block bitmap at 72 (bg #0 + 72), Inode bitmap at 104 (bg #0 + 104)
>  Inode table at 3713-4224 (bg #0 + 3713)
>  32703 free blocks, 8192 free inodes, 0 directories, 8192 unused inodes
>  Free blocks: 229441-262143
>  Free inodes: 57345-65536
>
> $ truncate -s 4G a.img
>
> $ e2fsck -f a.img
> e2fsck 1.42-WIP (02-Jul-2011)
> Pass 1: Checking inodes, blocks, and sizes
> Pass 2: Checking directory structure
> Pass 3: Checking directory connectivity
> Pass 4: Checking reference counts
> Pass 5: Checking group summary information
> a.img: 20864/65536 files (0.0% non-contiguous), 35953/262144 blocks
>
> $ dumpe2fs a.img
> dumpe2fs 1.42-WIP (02-Jul-2011)
> Filesystem volume name:   <none>
> Last mounted on:          /mnt
> Filesystem UUID:          4f2361c3-2755-4a6a-bf28-dd7e1a4dd772
> Filesystem magic number:  0xEF53
> Filesystem revision #:    1 (dynamic)
> Filesystem features:      has_journal ext_attr resize_inode dir_index filetype extent flex_bg sparse_super large_file huge_file uninit_bg dir_nlink extra_isize
> Filesystem flags:         signed_directory_hash
> Default mount options:    user_xattr acl
> Filesystem state:         clean
> Errors behavior:          Continue
> Filesystem OS type:       Linux
> Inode count:              65536
> Block count:              262144
> Reserved block count:     13107
> Free blocks:              226191
> Free inodes:              44672
> First block:              0
> Block size:               4096
> Fragment size:            4096
> Reserved GDT blocks:      63
> Blocks per group:         32768
> Fragments per group:      32768
> Inodes per group:         8192
> Inode blocks per group:   512
> Flex block group size:    32
> Filesystem created:       Tue Aug  2 02:29:45 2011
> Last mount time:          Tue Aug  2 02:29:50 2011
> Last write time:          Tue Aug  2 02:33:36 2011
> Mount count:              0
> Maximum mount count:      20
> Last checked:             Tue Aug  2 02:33:36 2011
> Check interval:           0 (<none>)
> Lifetime writes:          746 kB
> Reserved blocks uid:      0 (user root)
> Reserved blocks gid:      0 (group root)
> First inode:              11
> Inode size:               256
> Required extra isize:     28
> Desired extra isize:      28
> Journal inode:            8
> Default directory hash:   half_md4
> Directory Hash Seed:      a42d0c4e-0207-4fd4-94e7-b71bc107ae90
> Journal backup:           inode blocks
> Journal features:         (none)
> Journal size:             32M
> Journal length:           8192
> Journal sequence:         0x00000001
> Journal start:            0
>
>
> Group 0: (Blocks 0-32767) [ITABLE_ZEROED]
>  Checksum 0x3fe2, unused inodes 0
>  Primary superblock at 0, Group descriptors at 1-1
>  Reserved GDT blocks at 2-64
>  Block bitmap at 65 (+65), Inode bitmap at 97 (+97)
>  Inode table at 129-640 (+129)
>  24746 free blocks, 0 free inodes, 3 directories
>  Free blocks: 8022-32767
>  Free inodes:
> Group 1: (Blocks 32768-65535) [ITABLE_ZEROED]
>  Checksum 0x1361, unused inodes 0
>  Backup superblock at 32768, Group descriptors at 32769-32769
>  Reserved GDT blocks at 32770-32832
>  Block bitmap at 66 (bg #0 + 66), Inode bitmap at 98 (bg #0 + 98)
>  Inode table at 641-1152 (bg #0 + 641)
>  9128 free blocks, 0 free inodes, 975 directories
>  Free blocks: 49152-57343, 60376-60383, 60512-61439
>  Free inodes:
> Group 2: (Blocks 65536-98303) [ITABLE_ZEROED]
>  Checksum 0x3b77, unused inodes 4077
>  Block bitmap at 67 (bg #0 + 67), Inode bitmap at 99 (bg #0 + 99)
>  Inode table at 1153-1664 (bg #0 + 1153)
>  28672 free blocks, 4077 free inodes, 2302 directories, 4077 unused inodes
>  Free blocks: 69632-98303
>  Free inodes: 20500-24576
> Group 3: (Blocks 98304-131071) [ITABLE_ZEROED]
>  Checksum 0x372b, unused inodes 7865
>  Backup superblock at 98304, Group descriptors at 98305-98305
>  Reserved GDT blocks at 98306-98368
>  Block bitmap at 68 (bg #0 + 68), Inode bitmap at 100 (bg #0 + 100)
>  Inode table at 1665-2176 (bg #0 + 1665)
>  32703 free blocks, 7865 free inodes, 327 directories, 7865 unused inodes
>  Free blocks: 98369-131071
>  Free inodes: 24904-32768
> Group 4: (Blocks 131072-163839) [ITABLE_ZEROED]
>  Checksum 0x4c7a, unused inodes 8154
>  Block bitmap at 69 (bg #0 + 69), Inode bitmap at 101 (bg #0 + 101)
>  Inode table at 2177-2688 (bg #0 + 2177)
>  32768 free blocks, 8154 free inodes, 38 directories, 8154 unused inodes
>  Free blocks: 131072-163839
>  Free inodes: 32807-40960
> Group 5: (Blocks 163840-196607) [INODE_UNINIT, ITABLE_ZEROED]
>  Checksum 0xbd51, unused inodes 8192
>  Backup superblock at 163840, Group descriptors at 163841-163841
>  Reserved GDT blocks at 163842-163904
>  Block bitmap at 70 (bg #0 + 70), Inode bitmap at 102 (bg #0 + 102)
>  Inode table at 2689-3200 (bg #0 + 2689)
>  32703 free blocks, 8192 free inodes, 0 directories, 8192 unused inodes
>  Free blocks: 163905-196607
>  Free inodes: 40961-49152
> Group 6: (Blocks 196608-229375) [INODE_UNINIT, BLOCK_UNINIT, ITABLE_ZEROED]
>  Checksum 0xf453, unused inodes 8192
>  Block bitmap at 71 (bg #0 + 71), Inode bitmap at 103 (bg #0 + 103)
>  Inode table at 3201-3712 (bg #0 + 3201)
>  32768 free blocks, 8192 free inodes, 0 directories, 8192 unused inodes
>  Free blocks: 196608-229375
>  Free inodes: 49153-57344
> Group 7: (Blocks 229376-262143) [INODE_UNINIT, ITABLE_ZEROED]
>  Checksum 0xfcc2, unused inodes 8192
>  Backup superblock at 229376, Group descriptors at 229377-229377
>  Reserved GDT blocks at 229378-229440
>  Block bitmap at 72 (bg #0 + 72), Inode bitmap at 104 (bg #0 + 104)
>  Inode table at 3713-4224 (bg #0 + 3713)
>  32703 free blocks, 8192 free inodes, 0 directories, 8192 unused inodes
>  Free blocks: 229441-262143
>  Free inodes: 57345-65536
>
> $ sudo mount -t ext4 -o loop a.img /mnt/
> $ df
> [...]
> /dev/loop0             1032088    127324    852336  13% /mnt
>
> $ sudo umount /mnt
> -----------------------------------------
> -----------------------------------------
> -----------------------------------------
>
--
To unsubscribe from this list: send the line "unsubscribe linux-ext4" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html