Messages in this thread |  | | | Date | Tue, 30 Sep 1997 19:57:47 -0400 | | From | "Theodore Y. Ts'o" <> | | Subject | Re: ext2 and unlink(2) |
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From: Nick.Holloway@alfie.demon.co.uk (Nick Holloway) Date: 30 Sep 1997 21:04:58 +0100
Spooky. I read your message at home in the morning. Just over an hour later, when I happened to be in the machine room, the main Linux machine at work ate a filesystem.
attempt to access beyond end of device 16:01: rw=0, want=942814853, limit=768064 Kernel panic: EXT2-fs panic (device 16:01): ext2_write_inode: unable to read i-node block - inode=331778, block=942814852 attempt to access beyond end of device 16:01: rw=0, want=892678965, limit=768064 Kernel panic: EXT2-fs panic (device 16:01): ext2_read_inode: unable to read i-node block - inode=265721, block=892678964 attempt to access beyond end of device 16:01: rw=0, want=221853494, limit=768064 Kernel panic: EXT2-fs panic (device 16:01): read_block_bitmap: Cannot read block bitmap - block_group = 71, block_bitmap = 221853493
Does this look like the same sort of problem?
No, that's something else. When the kernel went to read a particular part of the inode table, the block number it tried to use (942814852) was clearly "out of range" for the disk.
The locations of the inode table, bitmap devices, etc. are read into memory when the filesystem is mounted, and they are validated to make sure they are sane at mount time. Therefore, some kind of problem must have corrupted the in-memory table created by the Linux kernel, later, after the filesystem was mounted. (Your server was probably running just for quite a while before the crash, right?)
Now, the block numbers 942814852, 892678964, and 22185349, if looked at as four char bytes, are mostly ASCII: "826\204", "5534", "\r975". This is not random garbage, so it's probably not memory bitrot. My money is on either a misdirected DMA (maybe caused by a bus transient of some kind) which overwrote the kernel data structure, or a kernel bug which caused the table to get overwritten by trash.
- Ted
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