2011/1/8 Marco Stornelli <marco.stornelli@xxxxxxxxx>: > On 07/01/2011 22:59, Tony Luck wrote: >> On Fri, Jan 7, 2011 at 12:30 PM, Marco Stornelli >> <marco.stornelli@xxxxxxxxx> 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. > > Is it a problem if you lost some logs? However do you expect that fsck > in this case will drop the inode? IF there could be some inconsistencies in the file-system AND as long as there is no way to fixup these inconsistencies than purging their allocated space THEN I think the best approach would be clearing these inconsistencies at the mount time and printing a WARNING message for debug/stats purpose. Otherwise a user-space tool would be better because it could be used in interactive mode, also. Obviously the best would be to not have any inconsistencies at all. However, in a real world, the thread-off between a journaling fs and a simpler one in terms of code and memory usage could make acceptable adopting a simpler fs than a journaled one. Kernel documentation should inform clearly the user about pro/cons of adopting a simpler fs especially about data loss conditions. -RAF -- To unsubscribe from this list: send the line "unsubscribe linux-embedded" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
