trace fsslower: Add support for statfs

[eiffel-fl]

Hi.

This PR adds support to trace statfs syscalls:

$ sudo ./ig trace fsslower -m 0 -c test                  francis/fsslower-statfs *% u=
RUNTIME.CONTAINERNAME                 PID        COMM             T         BYTES       OFFSET          LAT FILE                         
test                                  283280     bash             O             0            0            6 df                           
test                                  283280     bash             R           256            0            5 df                           
test                                  283280     bash             R           728           64            2 df                           
test                                  283280     bash             R            28          792            1 df                           
test                                  283280     bash             O             0            0            1 ld-linux-x86-64.so.2         
test                                  283280     bash             R            64            0            2 ld-linux-x86-64.so.2         
test                                  283280     bash             R           504           64            1 ld-linux-x86-64.so.2         
test                                  283280     df               O             0            0            5 ld.so.cache                  
test                                  283280     df               O             0            0            2 libc.so.6                    
test                                  283280     df               R           832            0            4 libc.so.6                    
test                                  283280     df               R           784           64            1 libc.so.6                    
test                                  283280     df               R           784           64            2 libc.so.6                    
test                                  283280     df               S             0            0            7 diff                         
test                                  283280     df               S             0            0            3 hosts
# Other terminalroot@45b252881c0d:/# df
Filesystem                 1K-blocks      Used Available Use% Mounted on
...

Best regards.

[jepio]

looks ok to me

[jepio]

why are you making op part of the key? do you expect probes to be interleaved for a thread?

[eiffel-fl]

From my test, it does not work using only tid as it would conflict between open and statfs.

[jepio]

can you add that information as a comment or in the commit message (saying that statfs entry can occur from within an open call)

…

On Fri, Nov 17, 2023, 16:49 eiffel-fl ***@***.***> wrote: ***@***.**** commented on this pull request. ------------------------------ In pkg/gadgets/trace/fsslower/tracer/bpf/fsslower.bpf.c <#2234 (comment)> : > +struct data_key { + __u32 tid; + enum fs_file_op op; +}; + From my test, it does not work using only tid as it would conflict between open and statfs. — Reply to this email directly, view it on GitHub <#2234 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/ABXINVWSKEHVZOW2RCJDHQ3YE6BPXAVCNFSM6AAAAAA7OPA5RSVHI2DSMVQWIX3LMV43YUDVNRWFEZLROVSXG5CSMV3GSZLXHMYTOMZXGMZDKNJWGU> . You are receiving this because you commented.Message ID: ***@***.***>

[eiffel-fl]

can you add that information as a comment or in the commit message (saying that statfs entry can occur from within an open call)
…
On Fri, Nov 17, 2023, 16:49 eiffel-fl @.> wrote: @.* commented on this pull request. ------------------------------ In pkg/gadgets/trace/fsslower/tracer/bpf/fsslower.bpf.c <#2234 (comment)> : > +struct data_key { + __u32 tid; + enum fs_file_op op; +}; + From my test, it does not work using only tid as it would conflict between open and statfs. — Reply to this email directly, view it on GitHub <#2234 (comment)>, or unsubscribe https://github.com/notifications/unsubscribe-auth/ABXINVWSKEHVZOW2RCJDHQ3YE6BPXAVCNFSM6AAAAAA7OPA5RSVHI2DSMVQWIX3LMV43YUDVNRWFEZLROVSXG5CSMV3GSZLXHMYTOMZXGMZDKNJWGU . You are receiving this because you commented.Message ID: @.***>

I rather added a comment in the struct declaration.

[alban]

It looks good to me from code reading.

It would be good to have an image-based gadget for this.

[alban]

I am curious if you have more details why open() would call statfs().

[eiffel-fl]

Thank you for the reviews!

[eiffel-fl]

It would be good to have an image-based gadget for this.

This is sadly not possible with the current state of image-based gadget as we need code to do the abstraction between the given function and the actual tracepoint.