PROBE::IOBLOCK\_TRACE(3stap) IO Scheduler and block IO Taps PROBE::IOBLOCK\_TRACE(3stap)

# [NAME](#NAME)

probe::ioblock\_trace.end - Fires whenever a block I/O transfer is complete.

# [SYNOPSIS](#SYNOPSIS)

```
probe ioblock_trace.end {}
```

# [VALUES](#VALUES)

*size*

total size in bytes

*p\_start\_sect*

points to the start sector of the partition structure of the device

*q*

request queue on which this bio was queued.

*vcnt*

bio vector count which represents number of array element (page, offset, length) which makes up this I/O request

*ino*

i-node number of the mapped file

*bytes\_done*

number of bytes transferred

*name*

name of the probe point

*rw*

binary trace for read/write request

*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

*bdev\_contains*

points to the device object which contains the partition (when bio structure represents a partition)

*idx*

offset into the bio vector array *phys\_segments* - number of segments in this bio after physical address coalescing is performed.

*devname*

block device name

*sector*

beginning sector for the entire bio

*bdev*

target block device

*opf*

operations and flags

# [CONTEXT](#CONTEXT)

The process signals the transfer is done.

# [SEE ALSO0](#SEE_ALSO0)

[*tapset::ioblock*(3stap)](/man/enterprise-packages/systemtap/tapset::ioblock.3stap)

September 2026 SystemTap Tapset Reference Ver

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Document: probe::ioblock_trace.end(3stap) from systemtap 5.6-r1 (Chainguard OS)
Source: https://sourceware.org/git/systemtap.git