On Wed, Sep 26, 2007 at 06:29:19PM -0500, Sachin Gaikwad wrote: > Is it not the case that VFS takes care of all filesystems available ? > VFS will see if a particular file belongs to ext3 or ext4 and call > that FS's drivers to access information ?? No, the VFS won't do that. The mount(8) command has been made smart enough enough to figure out what particular type of filesystem you are trying to mount by inspecting superblocks. There are however ways to confuse it: if you reformat an ext3 filesystem to reiserfs (version 3), mounting that filesystem without "-t reiserfs" will trick mount(8) into mounting it as an ext3 filesystem (which will usually fail). This is because the ext3 superblocks lives at offset 0x400, and the reiserfs superblock at 0x8000. When you format a partition as reiserfs, it will not erase old ext3 superblocks. Before looking for a reiserfs superblock, mount(8) first looks for an ext3 superblock. The old ext3 superblock wasn't erased, but usually most of the other ext3 structures are and so mount(8) will fail to mount the filesystem. Don't know if this particular "bug" is still there, but it has bitten me in the past. Erik -- They're all fools. Don't worry. Darwin may be slow, but he'll eventually get them. -- Matthew Lammers in alt.sysadmin.recovery
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