Date: Fri, 15 Mar 2002 11:00:59 +0100 From: Christoph Hellwig <hch@caldera.de> To: Terry Lambert <tlambert2@mindspring.com> Cc: AQUAMAN <yoatl@yahoo.com>, freebsd-fs@FreeBSD.ORG Subject: Re: filesystems compatibility Message-ID: <20020315110059.A32509@caldera.de> In-Reply-To: <3C9114DA.5A2D0591@mindspring.com>; from tlambert2@mindspring.com on Thu, Mar 14, 2002 at 01:23:38PM -0800 References: <20020312185747.98993.qmail@web13305.mail.yahoo.com> <3C8E72A3.6E9CBC6F@mindspring.com> <20020314183219.A28415@caldera.de> <3C9114DA.5A2D0591@mindspring.com>
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On Thu, Mar 14, 2002 at 01:23:38PM -0800, Terry Lambert wrote: > Perhaps, since you are knowledgeable in the Linux EXT2FS area, > you can answer the rest of the original question, now that I've > narrowed the answer to "some version of EXT2FS"? > > -- > > What is the highest revision level, and what are the maximum > feature flags that one can use interoperably between versions > of RedHat, FreeBSD, Debian, and Mandrake? I don't have all those Linux Distributions handy, but as the feature flags didn't change inbetween of Linux 2.2/2.4 release I'll just use generic 2.2/2.4 Kernels. Linux 2.4.18 [ext3 driver] (include/linux/ext3_fs.h): #define EXT3_FEATURE_COMPAT_SUPP 0 #define EXT3_FEATURE_INCOMPAT_SUPP (EXT3_FEATURE_INCOMPAT_FILETYPE| \ EXT3_FEATURE_INCOMPAT_RECOVER) #define EXT3_FEATURE_RO_COMPAT_SUPP (EXT3_FEATURE_RO_COMPAT_SPARSE_SUPER| \ EXT3_FEATURE_RO_COMPAT_LARGE_FILE| \ EXT3_FEATURE_RO_COMPAT_BTREE_DIR) Linux 2.4.18 (include/linux/ext2_fs.h): #define EXT2_FEATURE_COMPAT_SUPP 0 #define EXT2_FEATURE_INCOMPAT_SUPP EXT2_FEATURE_INCOMPAT_FILETYPE #define EXT2_FEATURE_RO_COMPAT_SUPP (EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER| \ EXT2_FEATURE_RO_COMPAT_LARGE_FILE| \ EXT2_FEATURE_RO_COMPAT_BTREE_DIR) Linux 2.2.18 (include/linux/ext2_fs.h): #define EXT2_FEATURE_COMPAT_SUPP 0 #define EXT2_FEATURE_INCOMPAT_SUPP EXT2_FEATURE_INCOMPAT_FILETYPE #define EXT2_FEATURE_RO_COMPAT_SUPP (EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER| \ EXT2_FEATURE_RO_COMPAT_LARGE_FILE| \ EXT2_FEATURE_RO_COMPAT_BTREE_DIR) FreeBSD-stable (sys/gnu/ext2fs/ext2_fs.h): #define EXT2_FEATURE_COMPAT_SUPP 0 #define EXT2_FEATURE_INCOMPAT_SUPP EXT2_FEATURE_INCOMPAT_FILETYPE #ifdef notyet #define EXT2_FEATURE_RO_COMPAT_SUPP (EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER| \ EXT2_FEATURE_RO_COMPAT_LARGE_FILE| \ EXT2_FEATURE_RO_COMPAT_BTREE_DIR) #else #define EXT2_FEATURE_RO_COMPAT_SUPP EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER #endif So all support revision 1 filesystems, no compat flag, the incompatible 4.4BSD-style dirent and sparse superblocks. Linux 2.2/2.4 support large files and compatiblity for the never released (!) btree directory support. The Linux ext3 driver also supports filesystems that need a log replay - for other drivers this will already be cleared by a fsck run. > PS: Different versions of FFS have different magic numbers; > the original number was Kirk's birthday. Only very few FFS derivates have different major numbers, infact I only know of SVR4.2MP SFS and various HP versions. On the other hand Solaris/Solaris-i386/4.4BSD/OpenStep seem to have the same one and are _very_ incompatible. > PPS: I'm more of an FFS maven than an EXT2FS maven; so I would > be more likely to be able to tell you about FFS interoperability > between systems. Thanks, I have enough of it after implementing SVR4.2MP UFS and SFS support for Linux.. Christoph -- Of course it doesn't work. We've performed a software upgrade. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-fs" in the body of the message
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