Re: [gentoo-user] Extended file attributes: ext4
On Sun, Apr 08, 2012 at 01:21:05PM -0500, Canek Peláez Valdés wrote: Note, however, that you *need* GRUB2 if your kernel lives in an ext4 partition that it's not longer compatible with ext3. Don't do the change without migrating to GRUB2 before. Hm... I wonder what I’m missing in my setup. I still run grub-0.97 (I like it more because it loads faster than Grub 2 ^^). Anyhoo, I have /boot on my root partition, and a longer while ago I made the switch from ext3 to ext4 through backup, reformat and restore. According to dumpe2fs, I have the following features enabled on the partition in question: has_journal ext_attr resize_inode dir_index filetype needs_recovery extent flex_bg sparse_super large_file huge_file uninit_bg dir_nlink extra_isize My fstab entry is minimalist: /dev/sda3 / ext4auto0 1 So how did I manage to get the system booted with grub 0.97 in the first place? I’m not using an “init thingy” BTW. ;-) -- Gruß | Greetings | Qapla' Please do not use my email addresses within any Facebook service. GNU jokes are not Unix jokes. pgpKjnOAKN55N.pgp Description: PGP signature
Re: [gentoo-user] Extended file attributes: ext4
On Fri, Apr 13, 2012 at 12:24:38AM +0200, Frank Steinmetzger wrote: On Sun, Apr 08, 2012 at 01:21:05PM -0500, Canek Peláez Valdés wrote: Note, however, that you *need* GRUB2 if your kernel lives in an ext4 partition that it's not longer compatible with ext3. Don't do the change without migrating to GRUB2 before. Hm... I wonder what I’m missing in my setup. […] So how did I manage to get the system booted with grub 0.97 in the first place? I’m not using an “init thingy” BTW. ;-) -_- I should have read the entire thread before answering. Canek asked the same thing and got the answer. -- Gruß | Greetings | Qapla' Please do not use my email addresses within any Facebook service. Dyslexics of the world untie! pgpxKD8NCL1ua.pgp Description: PGP signature
Re: [gentoo-user] Extended file attributes: ext4
On Thu, Apr 12, 2012 at 5:24 PM, Frank Steinmetzger war...@gmx.de wrote: On Sun, Apr 08, 2012 at 01:21:05PM -0500, Canek Peláez Valdés wrote: Note, however, that you *need* GRUB2 if your kernel lives in an ext4 partition that it's not longer compatible with ext3. Don't do the change without migrating to GRUB2 before. Hm... I wonder what I’m missing in my setup. I still run grub-0.97 (I like it more because it loads faster than Grub 2 ^^). Anyhoo, I have /boot on my root partition, and a longer while ago I made the switch from ext3 to ext4 through backup, reformat and restore. According to dumpe2fs, I have the following features enabled on the partition in question: has_journal ext_attr resize_inode dir_index filetype needs_recovery extent flex_bg sparse_super large_file huge_file uninit_bg dir_nlink extra_isize My fstab entry is minimalist: /dev/sda3 / ext4 auto 0 1 So how did I manage to get the system booted with grub 0.97 in the first place? I’m not using an “init thingy” BTW. ;-) As I said in my last email: OK, I went out and did my homework. GRUB legacy upstream doesn't support ext4 partitions (using extents, of course; without extents, they can be mounted as ext3), but Gentoo (as almost any other distribution under the sun) applies a patch to support it. Actually, it applies 37 patches, contained in grub-0.97-patches-1.12.tar.bz2, one of them called 850_all_grub-0.97_ext4.patch, which says: Gentoo bug #250829 - Include support for booting from ext4 partitions. This is the respun and tested patch adapted from http://code.google.com/p/grub4ext4/ so that it will apply with the rest of the Gentoo patches. Tested with: /boot on ext2 /boot on ext3 /boot on ext4 / on ext4 (no seperate /boot) Patch ported by Diego E. Pettenò (flameeyes) Testing by Robin H. Johnson (robbat2) Signed-off-by: Diego E. 'Flameeyes' Pettenò flamee...@gentoo.org Signed-off-by: Robin H. Johnson robb...@gentoo.org So mistery solved: GRUB legacy in Gentoo supports ext4, but it differs from upstream. When I was doing research for converting my filesystem to ext4, everywhere I looked it said that GRUB legacy doesn't support ext4... because it doesn't. Gentoo patches the sources, but upstream GRUB legacy does not support ext4. So I can finally stop telling people to migrate to GRUB2 if they want to use ext4. Regards. -- Canek Peláez Valdés Posgrado en Ciencia e Ingeniería de la Computación Universidad Nacional Autónoma de México
Re: [gentoo-user] Extended file attributes: ext4
On 9 April 2012, at 15:09, Michael Mol wrote: … So, ext2's extended attribute set listed support for compression (among other things), but it wasn't implemented. … Digging into the kenrel source for ext4 in linux-3.2.1.-gentoo-r2, there are symbols defined for managing compression, but they're not used. In short, compression support is specced, but not implemented. Many thanks. I appreciate your interest. Stroller.
Re: [gentoo-user] Extended file attributes: ext4
On 9 April 2012, at 13:04, Canek Peláez Valdés wrote: … This means ext4 mandatory if you want to use it, and this (usually) means GRUB2, which is still considered beta. … Interesting. Do you have extents enabled in the filesystem? Mine does: # tune2fs -l /dev/sda4 | grep features Filesystem features: has_journal ext_attr resize_inode dir_index filetype needs_recovery extent sparse_super large_file uninit_bg # df -Th Filesystem Type Size Used Avail Use% Mounted on rootfs rootfs228G 5.8G 211G 3% / /dev/root ext4 228G 5.8G 211G 3% / devtmpfs devtmpfs 875M 212K 875M 1% /dev rc-svcdir tmpfs 1.0M 60K 964K 6% /lib64/rc/init.d cgroup_roottmpfs 10M 0 10M 0% /sys/fs/cgroup shmtmpfs 876M 0 876M 0% /dev/shm # tune2fs -l /dev/root | grep extent Filesystem features: has_journal ext_attr resize_inode dir_index filetype needs_recovery extent flex_bg sparse_super large_file huge_file uninit_bg dir_nlink I was under the impression that GRUB legacy could not read ext4 filesystems with extents enabled; that was the primary reason I migrated to GRUB2. I believe there is a patch for GRUB legacy which adds ext4+extents support, but I don't think Gentoo applies it. No idea where it comes from, but you can see for yourself now you know to look. Stroller.
Re: [gentoo-user] Extended file attributes: ext4
On Tue, Apr 10, 2012 at 6:00 AM, Stroller strol...@stellar.eclipse.co.uk wrote: On 9 April 2012, at 13:04, Canek Peláez Valdés wrote: … This means ext4 mandatory if you want to use it, and this (usually) means GRUB2, which is still considered beta. … Interesting. Do you have extents enabled in the filesystem? Mine does: # tune2fs -l /dev/sda4 | grep features Filesystem features: has_journal ext_attr resize_inode dir_index filetype needs_recovery extent sparse_super large_file uninit_bg # df -Th Filesystem Type Size Used Avail Use% Mounted on rootfs rootfs 228G 5.8G 211G 3% / /dev/root ext4 228G 5.8G 211G 3% / devtmpfs devtmpfs 875M 212K 875M 1% /dev rc-svcdir tmpfs 1.0M 60K 964K 6% /lib64/rc/init.d cgroup_root tmpfs 10M 0 10M 0% /sys/fs/cgroup shm tmpfs 876M 0 876M 0% /dev/shm # tune2fs -l /dev/root | grep extent Filesystem features: has_journal ext_attr resize_inode dir_index filetype needs_recovery extent flex_bg sparse_super large_file huge_file uninit_bg dir_nlink I was under the impression that GRUB legacy could not read ext4 filesystems with extents enabled; that was the primary reason I migrated to GRUB2. I believe there is a patch for GRUB legacy which adds ext4+extents support, but I don't think Gentoo applies it. No idea where it comes from, but you can see for yourself now you know to look. OK, I went out and did my homework. GRUB legacy upstream doesn't support ext4 partitions (using extents, of course; without extents, they can be mounted as ext3), but Gentoo (as almost any other distribution under the sun) applies a patch to support it. Actually, it applies 37 patches, contained in grub-0.97-patches-1.12.tar.bz2, one of them called 850_all_grub-0.97_ext4.patch, which says: Gentoo bug #250829 - Include support for booting from ext4 partitions. This is the respun and tested patch adapted from http://code.google.com/p/grub4ext4/ so that it will apply with the rest of the Gentoo patches. Tested with: /boot on ext2 /boot on ext3 /boot on ext4 / on ext4 (no seperate /boot) Patch ported by Diego E. Pettenò (flameeyes) Testing by Robin H. Johnson (robbat2) Signed-off-by: Diego E. 'Flameeyes' Pettenò flamee...@gentoo.org Signed-off-by: Robin H. Johnson robb...@gentoo.org So mistery solved: GRUB legacy in Gentoo supports ext4, but it differs from upstream. When I was doing research for converting my filesystem to ext4, everywhere I looked it said that GRUB legacy doesn't support ext4... because it doesn't. Gentoo patches the sources, but upstream GRUB legacy does not support ext4. So I can finally stop telling people to migrate to GRUB2 if they want to use ext4. Thanks Stroller. Regards. -- Canek Peláez Valdés Posgrado en Ciencia e Ingeniería de la Computación Universidad Nacional Autónoma de México
Re: [gentoo-user] Extended file attributes: ext4
On 8 April 2012, at 19:21, Canek Peláez Valdés wrote: … And (optionally) convert all the files and directories to use extends: find directory -xdev -type f -print0 | xargs -0 chattr +e find directory -xdev -type d -print0 | xargs -0 chattr +e Ok, so I was just casually reading the chattr manpage, following this post… The letters `acdeijstuADST' select the new attributes for the files: append only (a), compressed (c), … A file with the `c' attribute set is automatically compressed on the disk by the kernel. A read from this file returns uncompressed data. A write to this file compresses data before storing them on the disk. COMPRESSED?!?! You mean, all I need to do is `touch new.dd.img chattr +c new.dd.img dd if=/dev/sdX of=new.dd.img` and I never again need to worry about piping dd through bzip and bunzip? If I have a massive great big uncompressed dd image, I can compress it as simply as touching a new file, changing this attribute on the new file and copying it over? Is there a reason I've been unaware of this? Why isn't this hugely popular? Stroller.
Re: [gentoo-user] Extended file attributes: ext4
On Mon, Apr 9, 2012 at 5:06 AM, Stroller strol...@stellar.eclipse.co.uk wrote: On 8 April 2012, at 19:21, Canek Peláez Valdés wrote: … And (optionally) convert all the files and directories to use extends: find directory -xdev -type f -print0 | xargs -0 chattr +e find directory -xdev -type d -print0 | xargs -0 chattr +e Ok, so I was just casually reading the chattr manpage, following this post… The letters `acdeijstuADST' select the new attributes for the files: append only (a), compressed (c), … A file with the `c' attribute set is automatically compressed on the disk by the kernel. A read from this file returns uncompressed data. A write to this file compresses data before storing them on the disk. COMPRESSED?!?! You mean, all I need to do is `touch new.dd.img chattr +c new.dd.img dd if=/dev/sdX of=new.dd.img` and I never again need to worry about piping dd through bzip and bunzip? If I have a massive great big uncompressed dd image, I can compress it as simply as touching a new file, changing this attribute on the new file and copying it over? Is there a reason I've been unaware of this? Why isn't this hugely popular? From the same man page: BUGS AND LIMITATIONS The `c', 's', and `u' attributes are not honored by the ext2 and ext3 filesystems as implemented in the current mainline Linux kernels. These attributes may be implemented in future versions of the ext2 and ext3 filesystems. This means ext4 mandatory if you want to use it, and this (usually) means GRUB2, which is still considered beta. Also, I don't see anywhere any mention on the compress algorithm used, which will probably mean bzip or gzip; I really don't think they use something like xz, for example, although maybe it's possible. Even more, it has to have some performance hit, specially on large files; and lastly, with the current harddrive size/price ratio, the option of automatically compress/decompress files is not really that necessary (remember DoubleSpace, from DOS days?). Oh, and I'm not sure about the following, but a *lot* of Unix programs use the same trick to write atomically files: They write the new version to a new file, and if that is successful, it moves the new file over the old one. In this case, I don't know how the new file can be created with the 'c' attribute (unless you set all the files to use it, and then for sure the performance hit will cost you). Anyhow, it's an incredible cool feature; I just don't know how useful it is with the size of modern disks. Regards. -- Canek Peláez Valdés Posgrado en Ciencia e Ingeniería de la Computación Universidad Nacional Autónoma de México
Re: [gentoo-user] Extended file attributes: ext4
On 9 April 2012, at 11:23, Canek Peláez Valdés wrote: … The `c', 's', and `u' attributes are not honored by the ext2 and ext3 filesystems as implemented in the current mainline Linux kernels. … This means ext4 mandatory if you want to use it, and this (usually) means GRUB2, which is still considered beta. # eix -Ic grub [I] sys-boot/grub (0.97-r10@03/07/12): GNU GRUB boot loader # df -Th Filesystem Type Size Used Avail Use% Mounted on rootfs rootfs228G 5.8G 211G 3% / /dev/root ext4 228G 5.8G 211G 3% / devtmpfs devtmpfs 875M 212K 875M 1% /dev rc-svcdir tmpfs 1.0M 60K 964K 6% /lib64/rc/init.d cgroup_roottmpfs 10M 0 10M 0% /sys/fs/cgroup shmtmpfs 876M 0 876M 0% /dev/shm # Also, I don't see anywhere any mention on the compress algorithm used, which will probably mean bzip or gzip; I really don't think they use something like xz, for example, although maybe it's possible. I was guessing LZMA - I don't believe it's the highest-compression algorithm out there, but it seems to have been around for a while. I'm pretty sure I've seen it in menuconfig's kernel options somewhere. Even more, it has to have some performance hit, specially on large files; Sure, but that applies to all file compression. and lastly, with the current harddrive size/price ratio, the option of automatically compress/decompress files is not really that necessary (remember DoubleSpace, from DOS days?). Yeah, in my case I've got about 1TB consumed by dd disk images which I've had to copy and unpack so I can mount them as loopback. These images are of the installed gentoo, got it booting, zero'd over the free space and factory-installation of Linpus types - i.e 5GB to 20GB when compressed. But the files are so huge because the system has this big empty 250GB or 500GB hard-drive installed from the factory, and I'm just dd'ing the whole thing, because who cares for more elegant methods when you're bzipping them, anyway, and you can just leave the copy running overnight? So this is a present issue for me right now. Oh, and I'm not sure about the following, but a *lot* of Unix programs use the same trick to write atomically files: They write the new version to a new file, and if that is successful, it moves the new file over the old one. In this case, I don't know how the new file can be created with the 'c' attribute (unless you set all the files to use it, and then for sure the performance hit will cost you). Yeah, I got the notion from `man chattr` (with the `c' attribute set … A read from this file returns uncompressed data. A write to this file compresses data before storing them on the disk.) that one might be initiate the dd copying process to a new file (which would write uncompressed data) then, in a new terminal, immediately change the compression attribute of the file, and that the *remainder* of the file would be compressed. I was saving this speculation to wait hopefully for a reply from someone who has actually used this feature. Stroller.
Re: [gentoo-user] Extended file attributes: ext4
On Mon, 9 Apr 2012 12:35:44 +0100, Stroller wrote: Yeah, I got the notion from `man chattr` (with the `c' attribute set … A read from this file returns uncompressed data. A write to this file compresses data before storing them on the disk.) that one might be initiate the dd copying process to a new file (which would write uncompressed data) then, in a new terminal, immediately change the compression attribute of the file, and that the *remainder* of the file would be compressed. It appears that you can set this attribute on a directory then all files created in that directory will inherit it. -- Neil Bothwick Don't be humble, you're not that great. signature.asc Description: PGP signature
Re: [gentoo-user] Extended file attributes: ext4
On Mon, Apr 9, 2012 at 6:35 AM, Stroller strol...@stellar.eclipse.co.uk wrote: On 9 April 2012, at 11:23, Canek Peláez Valdés wrote: … The `c', 's', and `u' attributes are not honored by the ext2 and ext3 filesystems as implemented in the current mainline Linux kernels. … This means ext4 mandatory if you want to use it, and this (usually) means GRUB2, which is still considered beta. # eix -Ic grub [I] sys-boot/grub (0.97-r10@03/07/12): GNU GRUB boot loader # df -Th Filesystem Type Size Used Avail Use% Mounted on rootfs rootfs 228G 5.8G 211G 3% / /dev/root ext4 228G 5.8G 211G 3% / devtmpfs devtmpfs 875M 212K 875M 1% /dev rc-svcdir tmpfs 1.0M 60K 964K 6% /lib64/rc/init.d cgroup_root tmpfs 10M 0 10M 0% /sys/fs/cgroup shm tmpfs 876M 0 876M 0% /dev/shm # Interesting. Do you have extents enabled in the filesystem? Mine does: # tune2fs -l /dev/sda4 | grep features Filesystem features: has_journal ext_attr resize_inode dir_index filetype needs_recovery extent sparse_super large_file uninit_bg I was under the impression that GRUB legacy could not read ext4 filesystems with extents enabled; that was the primary reason I migrated to GRUB2. I believe there is a patch for GRUB legacy which adds ext4+extents support, but I don't think Gentoo applies it. If GRUB legacy supports ext4 from upstream, then it's a new feature (or certainly, I hadn't heard about it until now). Regards. -- Canek Peláez Valdés Posgrado en Ciencia e Ingeniería de la Computación Universidad Nacional Autónoma de México
Re: [gentoo-user] Extended file attributes: ext4
On Mon, Apr 9, 2012 at 6:06 AM, Stroller strol...@stellar.eclipse.co.uk wrote: On 8 April 2012, at 19:21, Canek Peláez Valdés wrote: … And (optionally) convert all the files and directories to use extends: find directory -xdev -type f -print0 | xargs -0 chattr +e find directory -xdev -type d -print0 | xargs -0 chattr +e Ok, so I was just casually reading the chattr manpage, following this post… The letters `acdeijstuADST' select the new attributes for the files: append only (a), compressed (c), … A file with the `c' attribute set is automatically compressed on the disk by the kernel. A read from this file returns uncompressed data. A write to this file compresses data before storing them on the disk. COMPRESSED?!?! You mean, all I need to do is `touch new.dd.img chattr +c new.dd.img dd if=/dev/sdX of=new.dd.img` and I never again need to worry about piping dd through bzip and bunzip? If I have a massive great big uncompressed dd image, I can compress it as simply as touching a new file, changing this attribute on the new file and copying it over? Is there a reason I've been unaware of this? Why isn't this hugely popular? Stroller. From the kernel sources, Documentation/filesystems/ext2.txt: Specification = ext2 shares many properties with traditional Unix filesystems. It has the concepts of blocks, inodes and directories. It has space in the specification for Access Control Lists (ACLs), fragments, undeletion and compression though these are not yet implemented (some are available as separate patches). There is also a versioning mechanism to allow new features (such as journalling) to be added in a maximally compatible manner. So, ext2's extended attribute set listed support for compression (among other things), but it wasn't implemented. None of the other ext*.txt files reference compression. Digging into the kenrel source for ext4 in linux-3.2.1.-gentoo-r2, there are symbols defined for managing compression, but they're not used. In short, compression support is specced, but not implemented. -- :wq
[gentoo-user] Extended file attributes: ext4
Hi, is it possible to go from an ext4-filesystem with no extended file attributes to one with extended file attributes without reformatting the disk or other very risky low level things just by adding this feature to the kenrel (?) ? Thank you very much in advance for any help! Best regards, mcc
Re: [gentoo-user] Extended file attributes: ext4
On Sun, 8 Apr 2012 17:26:03 +0200, meino.cra...@gmx.de wrote about [gentoo-user] Extended file attributes: ext4: is it possible to go from an ext4-filesystem with no extended file attributes to one with extended file attributes without reformatting the disk or other very risky low level things just by adding this feature to the kenrel (?) ? Yes, it's simple. You need to ensure that your kernel configuration has the extended attribute support (ACL is a good idea too) and you have booted with the ext4 driver so configured. You then add the xattr option in /etc/fstab for the filesystem(s) where you want extended attribute support. If you do that before you reboot (as above) then you will have full extended attribute support. -- Regards, Dave [RLU #314465] *-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-* dwn...@ntlworld.com (David W Noon) *-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-*-* signature.asc Description: PGP signature
Re: [gentoo-user] Extended file attributes: ext4
On Sunday 08 Apr 2012 16:56:23 David W Noon wrote: On Sun, 8 Apr 2012 17:26:03 +0200, meino.cra...@gmx.de wrote about [gentoo-user] Extended file attributes: ext4: is it possible to go from an ext4-filesystem with no extended file attributes to one with extended file attributes without reformatting the disk or other very risky low level things just by adding this feature to the kenrel (?) ? Yes, it's simple. You need to ensure that your kernel configuration has the extended attribute support (ACL is a good idea too) and you have booted with the ext4 driver so configured. You then add the xattr option in /etc/fstab for the filesystem(s) where you want extended attribute support. If you do that before you reboot (as above) then you will have full extended attribute support. I thought that you are meant to pass such options on the CLI at the time you are formatting the partition ... is this incorrect? Of course if you must format the drive with such options then the data won't survive. -- Regards, Mick signature.asc Description: This is a digitally signed message part.
Re: [gentoo-user] Extended file attributes: ext4
Mick michaelkintz...@gmail.com [12-04-08 18:40]: On Sunday 08 Apr 2012 16:56:23 David W Noon wrote: On Sun, 8 Apr 2012 17:26:03 +0200, meino.cra...@gmx.de wrote about [gentoo-user] Extended file attributes: ext4: is it possible to go from an ext4-filesystem with no extended file attributes to one with extended file attributes without reformatting the disk or other very risky low level things just by adding this feature to the kenrel (?) ? Yes, it's simple. You need to ensure that your kernel configuration has the extended attribute support (ACL is a good idea too) and you have booted with the ext4 driver so configured. You then add the xattr option in /etc/fstab for the filesystem(s) where you want extended attribute support. If you do that before you reboot (as above) then you will have full extended attribute support. I thought that you are meant to pass such options on the CLI at the time you are formatting the partition ... is this incorrect? Of course if you must format the drive with such options then the data won't survive. -- Regards, Mick Hi, thank you very much for all the input. To clearify things a little: Status quo: System with ext4 and no extended attributes. Where I want to be: The same system with extended attributes. Way to go: No reformatting and mkfs and all that things. Only kernel reconfiguring / recompiling / rebooting and emerging some tools. Possible? Best regards, mcc
Re: [gentoo-user] Extended file attributes: ext4
On Sun, Apr 8, 2012 at 11:44 AM, meino.cra...@gmx.de wrote: Mick michaelkintz...@gmail.com [12-04-08 18:40]: On Sunday 08 Apr 2012 16:56:23 David W Noon wrote: On Sun, 8 Apr 2012 17:26:03 +0200, meino.cra...@gmx.de wrote about [gentoo-user] Extended file attributes: ext4: is it possible to go from an ext4-filesystem with no extended file attributes to one with extended file attributes without reformatting the disk or other very risky low level things just by adding this feature to the kenrel (?) ? Yes, it's simple. You need to ensure that your kernel configuration has the extended attribute support (ACL is a good idea too) and you have booted with the ext4 driver so configured. You then add the xattr option in /etc/fstab for the filesystem(s) where you want extended attribute support. If you do that before you reboot (as above) then you will have full extended attribute support. I thought that you are meant to pass such options on the CLI at the time you are formatting the partition ... is this incorrect? Of course if you must format the drive with such options then the data won't survive. -- Regards, Mick Hi, thank you very much for all the input. To clearify things a little: Status quo: System with ext4 and no extended attributes. Where I want to be: The same system with extended attributes. Way to go: No reformatting and mkfs and all that things. Only kernel reconfiguring / recompiling / rebooting and emerging some tools. Possible? As others had said, this is possible. I used this guide: http://www.debian-administration.org/articles/643 You need basically to enable the ext4-only features: tune2fs -O extents,uninit_bg,dir_index partition Do the fsck: fsck.ext4 -yfD partition And (optionally) convert all the files and directories to use extends: find directory -xdev -type f -print0 | xargs -0 chattr +e find directory -xdev -type d -print0 | xargs -0 chattr +e I did this on my laptop and desktop (including the root filesystem, booting into emergency mode with systemd), and everything worked perfectly. Note, however, that you *need* GRUB2 if your kernel lives in an ext4 partition that it's not longer compatible with ext3. Don't do the change without migrating to GRUB2 before. Regards. -- Canek Peláez Valdés Posgrado en Ciencia e Ingeniería de la Computación Universidad Nacional Autónoma de México
Re: [gentoo-user] Extended file attributes: ext4
Canek Peláez Valdés can...@gmail.com [12-04-08 20:28]: On Sun, Apr 8, 2012 at 11:44 AM, meino.cra...@gmx.de wrote: Mick michaelkintz...@gmail.com [12-04-08 18:40]: On Sunday 08 Apr 2012 16:56:23 David W Noon wrote: On Sun, 8 Apr 2012 17:26:03 +0200, meino.cra...@gmx.de wrote about [gentoo-user] Extended file attributes: ext4: is it possible to go from an ext4-filesystem with no extended file attributes to one with extended file attributes without reformatting the disk or other very risky low level things just by adding this feature to the kenrel (?) ? Yes, it's simple. You need to ensure that your kernel configuration has the extended attribute support (ACL is a good idea too) and you have booted with the ext4 driver so configured. You then add the xattr option in /etc/fstab for the filesystem(s) where you want extended attribute support. If you do that before you reboot (as above) then you will have full extended attribute support. I thought that you are meant to pass such options on the CLI at the time you are formatting the partition ... is this incorrect? Of course if you must format the drive with such options then the data won't survive. -- Regards, Mick Hi, thank you very much for all the input. To clearify things a little: Status quo: System with ext4 and no extended attributes. Where I want to be: The same system with extended attributes. Way to go: No reformatting and mkfs and all that things. Only kernel reconfiguring / recompiling / rebooting and emerging some tools. Possible? As others had said, this is possible. I used this guide: http://www.debian-administration.org/articles/643 You need basically to enable the ext4-only features: tune2fs -O extents,uninit_bg,dir_index partition Do the fsck: fsck.ext4 -yfD partition And (optionally) convert all the files and directories to use extends: find directory -xdev -type f -print0 | xargs -0 chattr +e find directory -xdev -type d -print0 | xargs -0 chattr +e I did this on my laptop and desktop (including the root filesystem, booting into emergency mode with systemd), and everything worked perfectly. Note, however, that you *need* GRUB2 if your kernel lives in an ext4 partition that it's not longer compatible with ext3. Don't do the change without migrating to GRUB2 before. Regards. -- Canek Peláez Valdés Posgrado en Ciencia e Ingeniería de la Computación Universidad Nacional Autónoma de México Ok, thanks for the introduction and the link, Canek! :) Best regards, mcc
Re: [gentoo-user] Extended file attributes: ext4
On Sun, Apr 8, 2012 at 2:21 PM, Canek Peláez Valdés can...@gmail.com wrote: On Sun, Apr 8, 2012 at 11:44 AM, meino.cra...@gmx.de wrote: Mick michaelkintz...@gmail.com [12-04-08 18:40]: On Sunday 08 Apr 2012 16:56:23 David W Noon wrote: On Sun, 8 Apr 2012 17:26:03 +0200, meino.cra...@gmx.de wrote about [gentoo-user] Extended file attributes: ext4: is it possible to go from an ext4-filesystem with no extended file attributes to one with extended file attributes without reformatting the disk or other very risky low level things just by adding this feature to the kenrel (?) ? Yes, it's simple. You need to ensure that your kernel configuration has the extended attribute support (ACL is a good idea too) and you have booted with the ext4 driver so configured. You then add the xattr option in /etc/fstab for the filesystem(s) where you want extended attribute support. If you do that before you reboot (as above) then you will have full extended attribute support. I thought that you are meant to pass such options on the CLI at the time you are formatting the partition ... is this incorrect? Of course if you must format the drive with such options then the data won't survive. -- Regards, Mick Hi, thank you very much for all the input. To clearify things a little: Status quo: System with ext4 and no extended attributes. Where I want to be: The same system with extended attributes. Way to go: No reformatting and mkfs and all that things. Only kernel reconfiguring / recompiling / rebooting and emerging some tools. Possible? As others had said, this is possible. I used this guide: http://www.debian-administration.org/articles/643 You need basically to enable the ext4-only features: tune2fs -O extents,uninit_bg,dir_index partition Um, why? Ext3 had extended attribute support, and ISTR the ext4 code being able to handle ext3 filesystems. -- :wq
Re: [gentoo-user] Extended file attributes: ext4
On Sun, Apr 8, 2012 at 1:41 PM, Michael Mol mike...@gmail.com wrote: On Sun, Apr 8, 2012 at 2:21 PM, Canek Peláez Valdés can...@gmail.com wrote: On Sun, Apr 8, 2012 at 11:44 AM, meino.cra...@gmx.de wrote: Mick michaelkintz...@gmail.com [12-04-08 18:40]: On Sunday 08 Apr 2012 16:56:23 David W Noon wrote: On Sun, 8 Apr 2012 17:26:03 +0200, meino.cra...@gmx.de wrote about [gentoo-user] Extended file attributes: ext4: is it possible to go from an ext4-filesystem with no extended file attributes to one with extended file attributes without reformatting the disk or other very risky low level things just by adding this feature to the kenrel (?) ? Yes, it's simple. You need to ensure that your kernel configuration has the extended attribute support (ACL is a good idea too) and you have booted with the ext4 driver so configured. You then add the xattr option in /etc/fstab for the filesystem(s) where you want extended attribute support. If you do that before you reboot (as above) then you will have full extended attribute support. I thought that you are meant to pass such options on the CLI at the time you are formatting the partition ... is this incorrect? Of course if you must format the drive with such options then the data won't survive. -- Regards, Mick Hi, thank you very much for all the input. To clearify things a little: Status quo: System with ext4 and no extended attributes. Where I want to be: The same system with extended attributes. Way to go: No reformatting and mkfs and all that things. Only kernel reconfiguring / recompiling / rebooting and emerging some tools. Possible? As others had said, this is possible. I used this guide: http://www.debian-administration.org/articles/643 You need basically to enable the ext4-only features: tune2fs -O extents,uninit_bg,dir_index partition Um, why? Ext3 had extended attribute support, and ISTR the ext4 code being able to handle ext3 filesystems. Didn't we already had this discussion? You can mount an ext3 partition as ext4, and it will be treated as ext4, but it will keep bein fully backwards compatible with ext3 (i.e., you can still mount it as ext3). This, however, negates the purpose of using ext4, as you are not using extents: From /usr/src/linux/Documentation/ext4.txt: - Create a new filesystem using the ext4 filesystem type: # mke2fs -t ext4 /dev/hda1 Or to configure an existing ext3 filesystem to support extents: # tune2fs -O extents /dev/hda1 The moment you enable extents on a ext4 partition, you need to fsck the filesystem, and stops being backwards compatible (i.e., it will no longer mount as ext3, and in particular GRUB will not be able to read the kernel inside it). If the partition has extents support, doesn't necessarily means that their files use extents: Therefore, if you want to fully convert your partition to ext4 (i.e., make all the files and directories to use extents), you need to chattr +e every file and directory in the filesystem, hence the commands: find directory -xdev -type f -print0 | xargs -0 chattr +e find directory -xdev -type d -print0 | xargs -0 chattr +e Regards. -- Canek Peláez Valdés Posgrado en Ciencia e Ingeniería de la Computación Universidad Nacional Autónoma de México
Re: [gentoo-user] Extended file attributes: ext4
On Sun, Apr 8, 2012 at 2:51 PM, Canek Peláez Valdés can...@gmail.com wrote: On Sun, Apr 8, 2012 at 1:41 PM, Michael Mol mike...@gmail.com wrote: On Sun, Apr 8, 2012 at 2:21 PM, Canek Peláez Valdés can...@gmail.com wrote: On Sun, Apr 8, 2012 at 11:44 AM, meino.cra...@gmx.de wrote: Mick michaelkintz...@gmail.com [12-04-08 18:40]: [snip] Status quo: System with ext4 and no extended attributes. Where I want to be: The same system with extended attributes. Way to go: No reformatting and mkfs and all that things. Only kernel reconfiguring / recompiling / rebooting and emerging some tools. Possible? As others had said, this is possible. I used this guide: http://www.debian-administration.org/articles/643 You need basically to enable the ext4-only features: tune2fs -O extents,uninit_bg,dir_index partition Um, why? Ext3 had extended attribute support, and ISTR the ext4 code being able to handle ext3 filesystems. Didn't we already had this discussion? You can mount an ext3 partition as ext4, and it will be treated as ext4, but it will keep bein fully backwards compatible with ext3 (i.e., you can still mount it as ext3). This, however, negates the purpose of using ext4, as you are not using extents: Sure, ext4 is a better filesystem than ext3. I'm not disputing that. I'm disputing that. I'm disputing two things: 1) That you need to convert a filesystem to ext4 in order to use extended attributes. 2) That you need to convert the filesystem at all; Meino's 'status quo' filesystem is already ext4, per the portion of his email I quoted. -- :wq
Re: [gentoo-user] Extended file attributes: ext4
On Sun, Apr 8, 2012 at 2:59 PM, Michael Mol mike...@gmail.com wrote: On Sun, Apr 8, 2012 at 2:51 PM, Canek Peláez Valdés can...@gmail.com wrote: On Sun, Apr 8, 2012 at 1:41 PM, Michael Mol mike...@gmail.com wrote: On Sun, Apr 8, 2012 at 2:21 PM, Canek Peláez Valdés can...@gmail.com wrote: On Sun, Apr 8, 2012 at 11:44 AM, meino.cra...@gmx.de wrote: Mick michaelkintz...@gmail.com [12-04-08 18:40]: [snip] Status quo: System with ext4 and no extended attributes. Where I want to be: The same system with extended attributes. Way to go: No reformatting and mkfs and all that things. Only kernel reconfiguring / recompiling / rebooting and emerging some tools. Possible? As others had said, this is possible. I used this guide: http://www.debian-administration.org/articles/643 You need basically to enable the ext4-only features: tune2fs -O extents,uninit_bg,dir_index partition Um, why? Ext3 had extended attribute support, and ISTR the ext4 code being able to handle ext3 filesystems. Didn't we already had this discussion? You can mount an ext3 partition as ext4, and it will be treated as ext4, but it will keep bein fully backwards compatible with ext3 (i.e., you can still mount it as ext3). This, however, negates the purpose of using ext4, as you are not using extents: Sure, ext4 is a better filesystem than ext3. I'm not disputing that. I'm disputing that. I'm disputing two things: (bleh. Editing error. Omit phrase 'I'm disputing that') -- :wq
Re: [gentoo-user] Extended file attributes: ext4
On Sun, Apr 8, 2012 at 1:59 PM, Michael Mol mike...@gmail.com wrote: On Sun, Apr 8, 2012 at 2:51 PM, Canek Peláez Valdés can...@gmail.com wrote: On Sun, Apr 8, 2012 at 1:41 PM, Michael Mol mike...@gmail.com wrote: On Sun, Apr 8, 2012 at 2:21 PM, Canek Peláez Valdés can...@gmail.com wrote: On Sun, Apr 8, 2012 at 11:44 AM, meino.cra...@gmx.de wrote: Mick michaelkintz...@gmail.com [12-04-08 18:40]: [snip] Status quo: System with ext4 and no extended attributes. Where I want to be: The same system with extended attributes. Way to go: No reformatting and mkfs and all that things. Only kernel reconfiguring / recompiling / rebooting and emerging some tools. Possible? As others had said, this is possible. I used this guide: http://www.debian-administration.org/articles/643 You need basically to enable the ext4-only features: tune2fs -O extents,uninit_bg,dir_index partition Um, why? Ext3 had extended attribute support, and ISTR the ext4 code being able to handle ext3 filesystems. Didn't we already had this discussion? You can mount an ext3 partition as ext4, and it will be treated as ext4, but it will keep bein fully backwards compatible with ext3 (i.e., you can still mount it as ext3). This, however, negates the purpose of using ext4, as you are not using extents: Sure, ext4 is a better filesystem than ext3. I'm not disputing that. I'm disputing that. I'm disputing two things: 1) That you need to convert a filesystem to ext4 in order to use extended attributes. 2) That you need to convert the filesystem at all; Meino's 'status quo' filesystem is already ext4, per the portion of his email I quoted. From Mick's mail: Status quo: System with ext4 and no extended attributes. Where I want to be: The same system with extended attributes. I assume with that he meant the extents option. Therefore, all the things I already said. Regards. -- Canek Peláez Valdés Posgrado en Ciencia e Ingeniería de la Computación Universidad Nacional Autónoma de México
Re: [gentoo-user] Extended file attributes: ext4
On Sun, Apr 8, 2012 at 3:04 PM, Canek Peláez Valdés can...@gmail.com wrote: On Sun, Apr 8, 2012 at 1:59 PM, Michael Mol mike...@gmail.com wrote: On Sun, Apr 8, 2012 at 2:51 PM, Canek Peláez Valdés can...@gmail.com wrote: On Sun, Apr 8, 2012 at 1:41 PM, Michael Mol mike...@gmail.com wrote: On Sun, Apr 8, 2012 at 2:21 PM, Canek Peláez Valdés can...@gmail.com wrote: On Sun, Apr 8, 2012 at 11:44 AM, meino.cra...@gmx.de wrote: Mick michaelkintz...@gmail.com [12-04-08 18:40]: [snip] Status quo: System with ext4 and no extended attributes. Where I want to be: The same system with extended attributes. Way to go: No reformatting and mkfs and all that things. Only kernel reconfiguring / recompiling / rebooting and emerging some tools. Possible? As others had said, this is possible. I used this guide: http://www.debian-administration.org/articles/643 You need basically to enable the ext4-only features: tune2fs -O extents,uninit_bg,dir_index partition Um, why? Ext3 had extended attribute support, and ISTR the ext4 code being able to handle ext3 filesystems. Didn't we already had this discussion? You can mount an ext3 partition as ext4, and it will be treated as ext4, but it will keep bein fully backwards compatible with ext3 (i.e., you can still mount it as ext3). This, however, negates the purpose of using ext4, as you are not using extents: Sure, ext4 is a better filesystem than ext3. I'm not disputing that. I'm disputing that. I'm disputing two things: 1) That you need to convert a filesystem to ext4 in order to use extended attributes. 2) That you need to convert the filesystem at all; Meino's 'status quo' filesystem is already ext4, per the portion of his email I quoted. From Mick's mail: Status quo: System with ext4 and no extended attributes. Where I want to be: The same system with extended attributes. I assume with that he meant the extents option. Therefore, all the things I already said. Ah. 'extents' and 'extended attributes' are completely different things. I did a bit of googling to confirm my recollection. FWIW, I came across this very excellent page in discussion of Ext4 compared to other and previous filesystems: http://kernelnewbies.org/Ext4 -- :wq
