* [pbs-devel] [PATCH] fix: use fragmented block size for space calculation
@ 2024-01-22 14:23 Gabriel Goller
2024-03-25 15:59 ` [pbs-devel] applied: " Thomas Lamprecht
0 siblings, 1 reply; 2+ messages in thread
From: Gabriel Goller @ 2024-01-22 14:23 UTC (permalink / raw)
To: pbs-devel
We currently calculate the size of a datastore using `statfs64`, which
returns the number of blocks in the fs and the two block sizes:
fragemented block size(f_frsize) and block size (f_bsize). To calculate
eg the total space in a datastore we use total_blocks * f_bsize, which
is not always correct.
`f_frsize` is the minimum unit of allocation on the filesystem (in
bytes) and in 99% of the cases equal to `f_bsize`, but in some cases
it differs. For example some filesystems allow smaller blocks for small
files, in case f_frsize < f_bsize. In that case, f_frsize * total_blocks
returns (mostly) the correct result (ceph also did some weird stuff, which is
now being fixed though [0][1]). `statvfs` also documents this as the
recommended way ('fsblkcnt_t f_blocks; /* Size of fs in f_frsize units */')[2].
This patch aligns the the behavior with the libc utilities (also used by
`df`) [3].
Motivation: [4] (Forum post)
[0]: https://tracker.ceph.com/issues/3793
[1]: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=92a49fb0f79f3300e6e50ddf56238e70678e4202
[2]: https://www.man7.org/linux/man-pages/man3/statvfs.3.html
[3]: https://git.savannah.gnu.org/cgit/gnulib.git/tree/lib/fsusage.c#n147
[4]: https://forum.proxmox.com/threads/pbs-3-1-2-wrong-datastore-information-sshfs.139875/#post-626959
Signed-off-by: Gabriel Goller <g.goller@proxmox.com>
---
proxmox-sys/src/fs/mod.rs | 12 ++++++++----
1 file changed, 8 insertions(+), 4 deletions(-)
diff --git a/proxmox-sys/src/fs/mod.rs b/proxmox-sys/src/fs/mod.rs
index 8fb677c..44c3da5 100644
--- a/proxmox-sys/src/fs/mod.rs
+++ b/proxmox-sys/src/fs/mod.rs
@@ -121,12 +121,16 @@ pub fn fs_info<P: ?Sized + nix::NixPath>(path: &P) -> nix::Result<FileSystemInfo
let res = path.with_nix_path(|cstr| unsafe { libc::statfs64(cstr.as_ptr(), &mut stat) })?;
nix::errno::Errno::result(res)?;
- let bsize = stat.f_bsize as u64;
+ let block_size = if stat.f_frsize == 0 {
+ stat.f_bsize as u64
+ } else {
+ stat.f_frsize as u64
+ };
Ok(FileSystemInformation {
- total: stat.f_blocks * bsize,
- used: (stat.f_blocks - stat.f_bfree) * bsize,
- available: stat.f_bavail * bsize,
+ total: stat.f_blocks * block_size,
+ used: (stat.f_blocks - stat.f_bfree) * block_size,
+ available: stat.f_bavail * block_size,
total_inodes: stat.f_files,
free_inodes: stat.f_ffree,
fs_type: stat.f_type,
--
2.43.0
^ permalink raw reply [flat|nested] 2+ messages in thread
* [pbs-devel] applied: [PATCH] fix: use fragmented block size for space calculation
2024-01-22 14:23 [pbs-devel] [PATCH] fix: use fragmented block size for space calculation Gabriel Goller
@ 2024-03-25 15:59 ` Thomas Lamprecht
0 siblings, 0 replies; 2+ messages in thread
From: Thomas Lamprecht @ 2024-03-25 15:59 UTC (permalink / raw)
To: Proxmox Backup Server development discussion, Gabriel Goller
Am 22/01/2024 um 15:23 schrieb Gabriel Goller:
> We currently calculate the size of a datastore using `statfs64`, which
> returns the number of blocks in the fs and the two block sizes:
> fragemented block size(f_frsize) and block size (f_bsize). To calculate
> eg the total space in a datastore we use total_blocks * f_bsize, which
> is not always correct.
>
> `f_frsize` is the minimum unit of allocation on the filesystem (in
> bytes) and in 99% of the cases equal to `f_bsize`, but in some cases
> it differs. For example some filesystems allow smaller blocks for small
> files, in case f_frsize < f_bsize. In that case, f_frsize * total_blocks
> returns (mostly) the correct result (ceph also did some weird stuff, which is
> now being fixed though [0][1]). `statvfs` also documents this as the
> recommended way ('fsblkcnt_t f_blocks; /* Size of fs in f_frsize units */')[2].
>
> This patch aligns the the behavior with the libc utilities (also used by
> `df`) [3].
>
> Motivation: [4] (Forum post)
>
> [0]: https://tracker.ceph.com/issues/3793
> [1]: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=92a49fb0f79f3300e6e50ddf56238e70678e4202
> [2]: https://www.man7.org/linux/man-pages/man3/statvfs.3.html
> [3]: https://git.savannah.gnu.org/cgit/gnulib.git/tree/lib/fsusage.c#n147
> [4]: https://forum.proxmox.com/threads/pbs-3-1-2-wrong-datastore-information-sshfs.139875/#post-626959
>
> Signed-off-by: Gabriel Goller <g.goller@proxmox.com>
> ---
> proxmox-sys/src/fs/mod.rs | 12 ++++++++----
> 1 file changed, 8 insertions(+), 4 deletions(-)
>
>
applied, thanks!
^ permalink raw reply [flat|nested] 2+ messages in thread
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