Line data Source code
1 : //! Wrapper around nix::sys::statvfs::Statvfs that allows for mocking.
2 :
3 : use camino::Utf8Path;
4 :
5 : pub enum Statvfs {
6 : Real(nix::sys::statvfs::Statvfs),
7 : Mock(mock::Statvfs),
8 : }
9 :
10 : // NB: on macOS, the block count type of struct statvfs is u32.
11 : // The workaround seems to be to use the non-standard statfs64 call.
12 : // Sincce it should only be a problem on > 2TiB disks, let's ignore
13 : // the problem for now and upcast to u64.
14 : impl Statvfs {
15 40 : pub fn get(tenants_dir: &Utf8Path, mocked: Option<&mock::Behavior>) -> nix::Result<Self> {
16 40 : if let Some(mocked) = mocked {
17 0 : Ok(Statvfs::Mock(mock::get(tenants_dir, mocked)?))
18 : } else {
19 40 : Ok(Statvfs::Real(nix::sys::statvfs::statvfs(
20 40 : tenants_dir.as_std_path(),
21 40 : )?))
22 : }
23 40 : }
24 :
25 : // NB: allow() because the block count type is u32 on macOS.
26 : #[allow(clippy::useless_conversion, clippy::unnecessary_fallible_conversions)]
27 40 : pub fn blocks(&self) -> u64 {
28 40 : match self {
29 40 : Statvfs::Real(stat) => u64::try_from(stat.blocks()).unwrap(),
30 0 : Statvfs::Mock(stat) => stat.blocks,
31 : }
32 40 : }
33 :
34 : // NB: allow() because the block count type is u32 on macOS.
35 : #[allow(clippy::useless_conversion, clippy::unnecessary_fallible_conversions)]
36 40 : pub fn blocks_available(&self) -> u64 {
37 40 : match self {
38 40 : Statvfs::Real(stat) => u64::try_from(stat.blocks_available()).unwrap(),
39 0 : Statvfs::Mock(stat) => stat.blocks_available,
40 : }
41 40 : }
42 :
43 80 : pub fn fragment_size(&self) -> u64 {
44 80 : match self {
45 80 : Statvfs::Real(stat) => stat.fragment_size(),
46 0 : Statvfs::Mock(stat) => stat.fragment_size,
47 : }
48 80 : }
49 :
50 0 : pub fn block_size(&self) -> u64 {
51 0 : match self {
52 0 : Statvfs::Real(stat) => stat.block_size(),
53 0 : Statvfs::Mock(stat) => stat.block_size,
54 : }
55 0 : }
56 :
57 : /// Get the available and total bytes on the filesystem.
58 40 : pub fn get_avail_total_bytes(&self) -> (u64, u64) {
59 : // https://unix.stackexchange.com/a/703650
60 40 : let blocksize = if self.fragment_size() > 0 {
61 40 : self.fragment_size()
62 : } else {
63 0 : self.block_size()
64 : };
65 :
66 : // use blocks_available (b_avail) since, pageserver runs as unprivileged user
67 40 : let avail_bytes = self.blocks_available() * blocksize;
68 40 : let total_bytes = self.blocks() * blocksize;
69 40 :
70 40 : (avail_bytes, total_bytes)
71 40 : }
72 : }
73 :
74 : pub mod mock {
75 : use camino::Utf8Path;
76 : use regex::Regex;
77 : use tracing::log::info;
78 :
79 : pub use pageserver_api::config::statvfs::mock::Behavior;
80 :
81 0 : pub fn get(tenants_dir: &Utf8Path, behavior: &Behavior) -> nix::Result<Statvfs> {
82 0 : info!("running mocked statvfs");
83 :
84 0 : match behavior {
85 : Behavior::Success {
86 0 : blocksize,
87 0 : total_blocks,
88 0 : ref name_filter,
89 0 : } => {
90 0 : let used_bytes = walk_dir_disk_usage(tenants_dir, name_filter.as_deref()).unwrap();
91 0 :
92 0 : // round it up to the nearest block multiple
93 0 : let used_blocks = used_bytes.div_ceil(*blocksize);
94 0 :
95 0 : if used_blocks > *total_blocks {
96 0 : panic!(
97 0 : "mocking error: used_blocks > total_blocks: {used_blocks} > {total_blocks}"
98 0 : );
99 0 : }
100 0 :
101 0 : let avail_blocks = total_blocks - used_blocks;
102 0 :
103 0 : Ok(Statvfs {
104 0 : blocks: *total_blocks,
105 0 : blocks_available: avail_blocks,
106 0 : fragment_size: *blocksize,
107 0 : block_size: *blocksize,
108 0 : })
109 : }
110 : #[cfg(feature = "testing")]
111 0 : Behavior::Failure { mocked_error } => Err((*mocked_error).into()),
112 : }
113 0 : }
114 :
115 0 : fn walk_dir_disk_usage(path: &Utf8Path, name_filter: Option<&Regex>) -> anyhow::Result<u64> {
116 0 : let mut total = 0;
117 0 : for entry in walkdir::WalkDir::new(path) {
118 0 : let entry = entry?;
119 0 : if !entry.file_type().is_file() {
120 0 : continue;
121 0 : }
122 0 : if !name_filter
123 0 : .as_ref()
124 0 : .map(|filter| filter.is_match(entry.file_name().to_str().unwrap()))
125 0 : .unwrap_or(true)
126 : {
127 0 : continue;
128 0 : }
129 0 : let m = match entry.metadata() {
130 0 : Ok(m) => m,
131 0 : Err(e) if is_not_found(&e) => {
132 0 : // some temp file which got removed right as we are walking
133 0 : continue;
134 : }
135 0 : Err(e) => {
136 0 : return Err(anyhow::Error::new(e)
137 0 : .context(format!("get metadata of {:?}", entry.path())))
138 : }
139 : };
140 0 : total += m.len();
141 : }
142 0 : Ok(total)
143 0 : }
144 :
145 0 : fn is_not_found(e: &walkdir::Error) -> bool {
146 0 : let Some(io_error) = e.io_error() else {
147 0 : return false;
148 : };
149 0 : let kind = io_error.kind();
150 0 : matches!(kind, std::io::ErrorKind::NotFound)
151 0 : }
152 :
153 : pub struct Statvfs {
154 : pub blocks: u64,
155 : pub blocks_available: u64,
156 : pub fragment_size: u64,
157 : pub block_size: u64,
158 : }
159 : }
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