Messages in this thread | | | Date | Fri, 7 Jan 2011 13:59:27 -0800 | Subject | Re: [PATCH 01/17] pramfs: documentation | From | Tony Luck <> |
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On Fri, Jan 7, 2011 at 12:30 PM, Marco Stornelli <marco.stornelli@gmail.com> wrote: > constraint). About the errors: pramfs does not maintain file data in the > page caches for normal file I/O, so no writeback, the read/write > operation are done with direct io and they are always sync. The data are > write protected in hw when the arch provide this facility (x86 does). > Inode contains a checksum and when there are problems they are marked as > bad. Superblock contains checksum and there is a redundant superblock.
But you can still get pramfs inconsistencies if the system crashes at an inopportune moment. E.g. when making files you write the new inode to pramfs, and then you insert the entry into the directory. A crash between these two operations leaves an allocated inode that doesn't appear in any directory. Without a fsck option, it will be hard to see that you have this problem, and your only recovery option is to wipe *all* files by making a new filesystem.
-Tony
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