probe::ioblock_trace.request — Fires just as a generic block I/O request is created for a bio.
name - name of the probe point
q - request queue on which this bio was queued.
devname - block device name
ino - i-node number of the mapped file
bytes_done - number of bytes transferred
sector - beginning sector for the entire bio
flags - see below
BIO_UPTODATE 0 ok after I/O completion
BIO_RW_BLOCK 1 RW_AHEAD set, and read/write would block
BIO_EOF 2 out-out-bounds error
BIO_SEG_VALID 3 nr_hw_seg valid
BIO_CLONED 4 doesn't own data
BIO_BOUNCED 5 bio is a bounce bio
BIO_USER_MAPPED 6 contains user pages
BIO_EOPNOTSUPP 7 not supported
rw - binary trace for read/write request
vcnt - bio vector count which represents number of array element (page, offset, length) which make up this I/O request
idx - offset into the bio vector array
phys_segments - number of segments in this bio after physical address coalescing is performed.
size - total size in bytes
bdev - target block device
bdev_contains - points to the device object which contains the partition (when bio structure represents a partition)
p_start_sect - points to the start sector of the partition structure of the device