ags ILOCK_EXCL caller xfs_vm_write_failed ^^^^^^^^^^^^^^^^^^^ The smoking gun - the write being failed and cleaning up delalloc blocks beyond EOF allocated by the failed write. xfs_getattr: xfs_ilock: flags IOLOCK_SHARED caller xfs_getbmap xfs_ilock: flags ILOCK_SHARED caller xfs_ilock_map_shared And that's where we died almost immediately afterwards. xfs_bmapi_read() found delalloc extent beyond current file in memory file size. Some debug I added to xfs_getbmap() showed the state just before the assert failure: ino 0x80e48: off 0xc00, fsb 0xffffffffffffffff, len 0x1, size 0x180000 start_fsb 0x106, end_fsb 0x638 ino flags 0x2 nex 0xd bmvcnt 0x555, len 0x3c58a6f23c0bf1, start 0xc00 ext 0: off 0x1fc, fsb 0x24782, len 0x254 ext 1: off 0x450, fsb 0x40851, len 0x30 ext 2: off 0x480, fsb 0xd99, len 0x1b8 ext 3: off 0x92f, fsb 0x4099a, len 0x3b ext 4: off 0x96d, fsb 0x41844, len 0x98 ext 5: off 0xbf1, fsb 0x408ab, len 0xf which shows that we found a single delalloc block beyond EOF (first line of output) when we were returning the map for a length somewhere around 10^16 bytes long (second line), and the on-disk extents showed they didn't go past EOF (last lines). Further debug added to xfs_vm_write_failed() showed this happened when punching out delalloc blocks beyond the end of the file after the failed write: [ 132.606693] ino 0x80e48: vwf to 0x181000, sze 0x180000 [ 132.609573] start_fsb 0xc01, end_fsb 0xc08 It punched the range 0xc01 -> 0xc08, but the range we really need to punch is 0xc00 -> 0xc07 (8 blocks from 0xc00) as this testing was run on a 512 byte block size filesystem (8 blocks per page). the punch from is 0xc00. So end_fsb is correct, but start_fsb is wrong as we punch from start_fsb for (end_fsb - start_fsb) blocks. Hence we are not punching the delalloc block beyond EOF in the case. The fix is simple - it's a silly off-by-one mistake in calculating the range. It's especially silly because the macro used to calculate the start_fsb already takes into account the case where the inode size is an exact multiple of the filesystem block size... Signed-off-by: Dave Chinner Reviewed-by: Eric Sandeen Signed-off-by: Ben Myers ©