Your SATA disk had enough errors that the ATA link was completely reset, and the device was detached and then reattached. As far as kernel is concerned, it's a new device. The problem is that the ext4 mount was for the old device, not the newly attached device. So attempts to read from the device is returning errors from the block device layer. > but later on, suddenly, without any other related message in between as far as I can see: > > Aug 28 11:47:39 vostro kernel: [25874.121506] EXT4-fs error (device sdb1): __ext4_get_inode_loc:4039: inode #163315715: block 653262880: comm memcheck-amd64-: unable to read itable block > Aug 28 11:47:39 vostro kernel: [25874.121510] EXT4-fs error (device sdb1) in ext4_reserve_inode_write:4973: IO failure This was just the first timat the system had tried accessing the file system, and when it tried reading from the device, it got an I/O failure from the device pretty much immediately. > So kernel was trying for 10 minutes before it gave up? I'm guessing your file system is configured with errors=continued? > Any clues what I should look at? Few days ago memtest86+ went fine through all 16GB of RAM (Dell Vostro 3550). I do not know if the PCI/ACPI change is related or not. The error is happening at the block device layer. So I don't know whether it's caused by the table getting bumped, or something getting confused when the device tried to enter some kind of power saving mode, etc. - Ted -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html