I came accross strange behavior when trying to check my ext4 filesystem. I'm using 4 GB SD card with my Raspberry and it suddenly crashed. So when connected with usb reader to another pc I got fancy logs about device size in logs. First SD card size was detected correctly (3.99GB), then few connectivity errors occurred, and voila - my SD card reported 1.68 TB capacity. My ext4 partition is sdg2 - whole log is related to detecting the same sd card below: Jan 27 18:35:23 byziek kernel: [ 56.121960] scsi 10:0:0:0: Direct-Access ChipsBnk SD/MMCReader 4080 PQ: 0 ANSI: 2 Jan 27 18:35:23 byziek kernel: [ 56.126827] sd 10:0:0:0: Attached scsi generic sg7 type 0 Jan 27 18:35:23 byziek kernel: [ 56.128453] sd 10:0:0:0: [sdg] 7806976 512-byte logical blocks: (3.99 GB/3.72 GiB) Jan 27 18:35:23 byziek kernel: [ 56.129847] sd 10:0:0:0: [sdg] Write Protect is off Jan 27 18:35:23 byziek kernel: [ 56.129854] sd 10:0:0:0: [sdg] Mode Sense: 0b 00 00 08 Jan 27 18:35:23 byziek kernel: [ 56.131308] sd 10:0:0:0: [sdg] No Caching mode page found Jan 27 18:35:23 byziek kernel: [ 56.131316] sd 10:0:0:0: [sdg] Assuming drive cache: write through Jan 27 18:35:23 byziek kernel: [ 56.135815] sd 10:0:0:0: [sdg] No Caching mode page found Jan 27 18:35:23 byziek kernel: [ 56.135820] sd 10:0:0:0: [sdg] Assuming drive cache: write through Jan 27 18:35:23 byziek kernel: [ 56.137194] sdg: sdg1 sdg2 Jan 27 18:35:23 byziek kernel: [ 56.140837] sd 10:0:0:0: [sdg] No Caching mode page found Jan 27 18:35:23 byziek kernel: [ 56.140845] sd 10:0:0:0: [sdg] Assuming drive cache: write through Jan 27 18:35:23 byziek kernel: [ 56.140849] sd 10:0:0:0: [sdg] Attached SCSI removable disk Jan 27 18:35:33 byziek kernel: [ 66.461566] sd 10:0:0:0: [sdg] Media Changed Jan 27 18:35:33 byziek kernel: [ 66.461572] sd 10:0:0:0: [sdg] Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE Jan 27 18:35:33 byziek kernel: [ 66.461577] sd 10:0:0:0: [sdg] Sense Key : Unit Attention [current] Jan 27 18:35:33 byziek kernel: [ 66.461582] sd 10:0:0:0: [sdg] Add. Sense: Not ready to ready change, medium may have changed Jan 27 18:35:33 byziek kernel: [ 66.461589] sd 10:0:0:0: [sdg] CDB: Read(10): 28 00 00 76 4e f8 00 00 08 00 Jan 27 18:35:33 byziek kernel: [ 66.461599] end_request: I/O error, dev sdg, sector 7753464 Jan 27 18:35:33 byziek kernel: [ 66.461605] Buffer I/O error on device sdg2, logical block 950239 Jan 27 18:35:44 byziek kernel: [ 76.645575] sd 10:0:0:0: [sdg] Media Changed Jan 27 18:35:44 byziek kernel: [ 76.645581] sd 10:0:0:0: [sdg] Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE Jan 27 18:35:44 byziek kernel: [ 76.645586] sd 10:0:0:0: [sdg] Sense Key : Unit Attention [current] Jan 27 18:35:44 byziek kernel: [ 76.645591] sd 10:0:0:0: [sdg] Add. Sense: Not ready to ready change, medium may have changed Jan 27 18:35:44 byziek kernel: [ 76.645598] sd 10:0:0:0: [sdg] CDB: Read(10): 28 00 00 00 18 b8 00 00 08 00 Jan 27 18:35:44 byziek kernel: [ 76.645608] end_request: I/O error, dev sdg, sector 6328 Jan 27 18:35:44 byziek kernel: [ 76.645614] Buffer I/O error on device sdg1, logical block 279 Jan 27 18:35:44 byziek kernel: [ 76.647314] sd 10:0:0:0: [sdg] 3288073216 512-byte logical blocks: (1.68 TB/1.53 TiB) Jan 27 18:35:44 byziek kernel: [ 76.654827] sd 10:0:0:0: [sdg] No Caching mode page found Jan 27 18:35:44 byziek kernel: [ 76.654835] sd 10:0:0:0: [sdg] Assuming drive cache: write through Jan 27 18:35:44 byziek kernel: [ 76.746816] sd 10:0:0:0: [sdg] No Caching mode page found Jan 27 18:35:44 byziek kernel: [ 76.746822] sd 10:0:0:0: [sdg] Assuming drive cache: write through Jan 27 18:35:44 byziek kernel: [ 76.747709] sdg: sdg1 sdg2 Jan 27 18:35:46 byziek kernel: [ 78.525565] sd 10:0:0:0: [sdg] Media Changed Jan 27 18:35:46 byziek kernel: [ 78.525571] sd 10:0:0:0: [sdg] Result: hostbyte=DID_OK driverbyte=DRIVER_SENSE Jan 27 18:35:46 byziek kernel: [ 78.525576] sd 10:0:0:0: [sdg] Sense Key : Unit Attention [current] Jan 27 18:35:46 byziek kernel: [ 78.525582] sd 10:0:0:0: [sdg] Add. Sense: Not ready to ready change, medium may have changed Jan 27 18:35:46 byziek kernel: [ 78.525589] sd 10:0:0:0: [sdg] CDB: Read(10): 28 00 c3 fc 03 80 00 00 08 00 Jan 27 18:35:46 byziek kernel: [ 78.525598] end_request: I/O error, dev sdg, sector 3288073088 Jan 27 18:35:46 byziek kernel: [ 78.525604] Buffer I/O error on device sdg, logical block 411009136 Jan 27 18:35:46 byziek kernel: [ 78.533318] sd 10:0:0:0: [sdg] 7806976 512-byte logical blocks: (3.99 GB/3.72 GiB) Jan 27 18:35:46 byziek kernel: [ 78.535809] sd 10:0:0:0: [sdg] No Caching mode page found Jan 27 18:35:46 byziek kernel: [ 78.535814] sd 10:0:0:0: [sdg] Assuming drive cache: write through Jan 27 18:35:46 byziek kernel: [ 78.539817] sd 10:0:0:0: [sdg] No Caching mode page found Jan 27 18:35:46 byziek kernel: [ 78.539822] sd 10:0:0:0: [sdg] Assuming drive cache: write through Jan 27 18:35:46 byziek kernel: [ 78.540719] sdg: sdg1 sdg2 As a result some directory entries are pointing to blocks which are out of disk area. So when I try to fix filesystem with e2fsck i got: e2fsck 1.42.12 (29-Aug-2014) Pass 1: Checking inodes, blocks, and sizes Error reading block 8796093119321 (Invalid argument) while reading directory block. Ignore error<y>? no Error reading block 2147592353 (Invalid argument) while reading directory block. Ignore error<y>? no Error reading block 274878023742 (Invalid argument) while reading directory block. Ignore error<y>? no Error reading block 1073851752 (Invalid argument) while reading directory block. Ignore error<y>? no Error reading block 274877916439 (Invalid argument) while reading directory block. Ignore error<y>? no Pass 2: Checking directory structure Pass 3: Checking directory connectivity Pass 4: Checking reference counts Pass 5: Checking group summary information 53701 inodes used (23.57%, out of 227824) 180 non-contiguous files (0.3%) 27 non-contiguous directories (0.1%) # of inodes with ind/dind/tind blocks: 2/1/1 Extent depth histogram: 49736/72 527274 blocks used (55.49%, out of 950272) 0 bad blocks 100 large files 40265 regular files 6741 directories 61 character device files 25 block device files 1 fifo 16928 links 6580 symbolic links (3777 fast symbolic links) 19 sockets Block numbers are insane for 4GB filesystem, and e2fsck is unable to fix them. Currently working on image copied from SD card to hard disk. While trying to fix image with older fsck (1.42.4) image has grown from 4GB to ~1000GB. Any hint how to approach such problem? e2fsck without force-ing treats this filesystem as clean: rpi_sdg2: clean, 53701/227824 files, 527274/950272 blocks Martin -- 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