acl_xattr vs acl_tdb
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From: Jeremy Allison on 26 Mar 2010 11:30 On Fri, Mar 26, 2010 at 01:39:31PM +0100, Volker Lendecke wrote: > On Fri, Mar 26, 2010 at 08:38:19AM -0400, simo wrote: > > > > There's something I would really like to know! But somehow it seems to > > > > be a secret of the gods that us mere mortals are not allowed to penetrate... > > > > > > Please say if there is any size restriction for xattrs in > > > XFS. Hopefully there is none, which would mean that you can > > > fill the whole file system with a single security descriptor > > > if you wish. > > > > If I remember correctly XFS used to have a size limit of 64KiB per > > xattr. > > Shall I call you god now? :-) Nah. I knew that too, but Simo is on the East Coast and so answered first :-). -- To unsubscribe from this list go to the following URL and read the instructions: https://lists.samba.org/mailman/options/samba
From: simo on 26 Mar 2010 11:50 On Fri, 2010-03-26 at 08:23 -0700, Jeremy Allison wrote: > On Fri, Mar 26, 2010 at 01:39:31PM +0100, Volker Lendecke wrote: > > On Fri, Mar 26, 2010 at 08:38:19AM -0400, simo wrote: > > > > > There's something I would really like to know! But somehow it seems to > > > > > be a secret of the gods that us mere mortals are not allowed to penetrate... > > > > > > > > Please say if there is any size restriction for xattrs in > > > > XFS. Hopefully there is none, which would mean that you can > > > > fill the whole file system with a single security descriptor > > > > if you wish. > > > > > > If I remember correctly XFS used to have a size limit of 64KiB per > > > xattr. > > > > Shall I call you god now? :-) > > Nah. I knew that too, but Simo is on the East Coast > and so answered first :-). Are you trying to dispute my newly acquired deity status ?! Beware! :-P Simo. -- Simo Sorce Samba Team GPL Compliance Officer <simo(a)samba.org> Principal Software Engineer at Red Hat, Inc. <simo(a)redhat.com> -- To unsubscribe from this list go to the following URL and read the instructions: https://lists.samba.org/mailman/options/samba
From: simo on 26 Mar 2010 12:30 On Fri, 2010-03-26 at 10:53 -0400, simo wrote: > On Fri, 2010-03-26 at 13:06 +0000, Miguel Medalha wrote: > > > If I remember correctly XFS used to have a size limit of 64KiB per > > > xattr. > > > > > > > What about ext3 & ext4? > > Always IIRC, they should be limited by the inode size, which is 4KiB, > but this information is old, and should be verified for ext4. Ok I just checked. On ext4 the total size of *all* xattrs can't be larger than 4k and some. There is only 1 block you can allocate beyond the file inode. So careful on the amount of data you store in ext4 attrs. If you think you'll have fatty Windows ACLs to store I guess XFS is a better choice right now. Simo. -- Simo Sorce Samba Team GPL Compliance Officer <simo(a)samba.org> Principal Software Engineer at Red Hat, Inc. <simo(a)redhat.com> -- To unsubscribe from this list go to the following URL and read the instructions: https://lists.samba.org/mailman/options/samba
From: Jeremy Allison on 26 Mar 2010 12:50 On Fri, Mar 26, 2010 at 12:40:49PM -0400, simo wrote: > On Fri, 2010-03-26 at 12:28 -0400, simo wrote: > > On Fri, 2010-03-26 at 10:53 -0400, simo wrote: > > > On Fri, 2010-03-26 at 13:06 +0000, Miguel Medalha wrote: > > > > > If I remember correctly XFS used to have a size limit of 64KiB per > > > > > xattr. > > > > > > > > > > > > > What about ext3 & ext4? > > > > > > Always IIRC, they should be limited by the inode size, which is 4KiB, > > > but this information is old, and should be verified for ext4. > > > > Ok I just checked. > > On ext4 the total size of *all* xattrs can't be larger than 4k and some. > > > > There is only 1 block you can allocate beyond the file inode. > > > > So careful on the amount of data you store in ext4 attrs. If you think > > you'll have fatty Windows ACLs to store I guess XFS is a better choice > > right now. > > Ah just to add insult to injury, remember that the xattr space is shared > with selinux labels *and* posix ACLs contents. > > So it is a tight spot indeed. And don't forget the DOS attributes as well :-). -- To unsubscribe from this list go to the following URL and read the instructions: https://lists.samba.org/mailman/options/samba
From: simo on 26 Mar 2010 12:50
On Fri, 2010-03-26 at 12:28 -0400, simo wrote: > On Fri, 2010-03-26 at 10:53 -0400, simo wrote: > > On Fri, 2010-03-26 at 13:06 +0000, Miguel Medalha wrote: > > > > If I remember correctly XFS used to have a size limit of 64KiB per > > > > xattr. > > > > > > > > > > What about ext3 & ext4? > > > > Always IIRC, they should be limited by the inode size, which is 4KiB, > > but this information is old, and should be verified for ext4. > > Ok I just checked. > On ext4 the total size of *all* xattrs can't be larger than 4k and some. > > There is only 1 block you can allocate beyond the file inode. > > So careful on the amount of data you store in ext4 attrs. If you think > you'll have fatty Windows ACLs to store I guess XFS is a better choice > right now. Ah just to add insult to injury, remember that the xattr space is shared with selinux labels *and* posix ACLs contents. So it is a tight spot indeed. Simo. -- Simo Sorce Samba Team GPL Compliance Officer <simo(a)samba.org> Principal Software Engineer at Red Hat, Inc. <simo(a)redhat.com> -- To unsubscribe from this list go to the following URL and read the instructions: https://lists.samba.org/mailman/options/samba |