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627f808e4b
According to xfs_admin(8):
> -c 0|1 Enable (1) or disable (0) lazy-counters in the filesys‐
> tem.
>
> Lazy-counters may not be disabled on Version 5 su‐
> perblock filesystems (i.e. those with metadata CRCs en‐
> abled).
>
> [...]
According to mkfs.xfs(1):
> -m global_metadata_options
> Section Name: [metadata]
> These options specify metadata format options that ei‐
> ther apply to the entire filesystem or aren't easily
> characterised by a specific functionality group. The
> valid global_metadata_options are:
>
> [...]
>
> crc=value
> This is used to create a filesystem which
> maintains and checks CRC information in all
> metadata objects on disk. The value is ei‐
> ther 0 to disable the feature, or 1 to en‐
> able the use of CRCs.
>
> [...]
>
> By default, mkfs.xfs will enable metadata
> CRCs.
Consistently with the above, the first "xfs_admin" test case in
"generator/actions_core.ml", which attempts to disable lazy counters,
always fails:
> 534/550 test_xfs_admin_0
> libguestfs: error: xfs_admin: /dev/sda1: Cannot disable lazy-counters on V5 fs
We can resolve this test failure in three ways:
(1) Extend do_mkfs() [daemon/mkfs.c], possibly even introduce
do_mkfs_xfs(), and permit the caller to specify "-m crc=0" for
mkfs.xfs. Then use this option when the temporary filesystem is
created in the XFS test that disables lazy counters.
(2) Extend the "guestfs_int_xfsinfo" structure in the libguestfs-common
project, with an "xfs_crc" field. Extend parse_xfs_info()
[daemon/xfs.c] to populate the field from "meta-data=...crc=[01]".
Modify the test case to check the following post-condition:
xfs_crc || xfs_lazycount == 0
instead of the current
xfs_lazycount == 0
effectively ignoring "xfs_lazycount" when "xfs_crc" is set.
(3) Remove the test altogether that attempts to disable lazy counters
after filesystem creation.
Given that new XFS filesystems are created with metadata CRCs enabled by
default, and several XFS features depend on metadata CRCs being enabled,
this patch implements option (3).
Signed-off-by: Laszlo Ersek <lersek@redhat.com>
Message-Id: <20210920052335.3358-4-lersek@redhat.com>
Acked-by: Richard W.M. Jones <rjones@redhat.com>
This program generates a large amount of code and documentation for all the daemon actions. To add a new action there are only two files you need to change, 'actions_*.ml' to describe the interface, and daemon/<somefile>.c to write the implementation. After editing these files, build it (make -C generator) to regenerate all the output files. 'make' will rerun this automatically when necessary. IMPORTANT: This program should NOT print any warnings at compile time or run time. If it prints warnings, you should treat them as errors. OCaml tips: (1) In emacs, install tuareg-mode to display and format OCaml code correctly. 'vim' comes with a good OCaml editing mode by default. (2) Read the resources at http://ocaml.org/learn/ (3) A module called 'Foo' is defined in one or two files called 'foo.mli' and 'foo.ml' (NB: lowercase first letter). The *.mli file, if present, defines the public interface for the module. The *.ml file is the implementation. If the *.mli file is missing then everything is exported. Some notable files in this directory: actions_*.ml The libguestfs API. proc_nr.ml Procedure numbers associated with each API. structs.ml Structures returned by the API. c.ml Generate C API. <lang>.ml Generate bindings for <lang>. main.ml The main generator program. Note about long descriptions: When referring to another action, use the format C<guestfs_other> (ie. the full name of the C function). This will be replaced as appropriate in other language bindings. Apart from that, long descriptions are just perldoc paragraphs. Note about extending functions: In general you cannot change the name, number of required arguments or type of required arguments of a function, since this would break backwards compatibility. You may add another optional argument, *if* the function has >= 1 optional arguments already. Add it at the end of the list. You may add optional arguments to a function that doesn't have any. However you *must* set the once_had_no_optargs flag to true, so that the relevant backwards compatibility bindings can be added.