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daemon: Account for deleted store files when deduplication is on.

Previously, a store item that is a regular file would not be accounted
for in the 'bytesFreed' value computed by 'deletePath' because its
'st_nlink' count would always be >= 2.  This commit fixes that.

* nix/libutil/util.hh (deletePath): Add optional 'linkThreshold' argument.
* nix/libutil/util.cc (_deletePath): Add 'linkThreshold' argument and
honor it.  Pass it down in recursive call.
(deletePath): Add 'linkThreshold' and honor it.
* nix/libstore/gc.cc (LocalStore::deleteGarbage): Pass 'linkThreshold'
argument to 'deletePath', with a value of 2 when PATH is a store item
and deduplication is on.
gn-latest-20200428
Ludovic Courtès 2 years ago
parent
commit
7033c7692c
No known key found for this signature in database GPG Key ID: 90B11993D9AEBB5
  1. 9
      nix/libstore/gc.cc
  2. 10
      nix/libutil/util.cc
  3. 6
      nix/libutil/util.hh

9
nix/libstore/gc.cc

@ -392,7 +392,14 @@ bool LocalStore::isActiveTempFile(const GCState & state,
void LocalStore::deleteGarbage(GCState & state, const Path & path)
{
unsigned long long bytesFreed;
deletePath(path, bytesFreed);
/* When deduplication is on, store items always have at least two links:
the one at PATH, and one in /gnu/store/.links. In that case, increase
bytesFreed when PATH has two or fewer links. */
size_t linkThreshold =
(settings.autoOptimiseStore && isStorePath(path)) ? 2 : 1;
deletePath(path, bytesFreed, linkThreshold);
state.results.bytesFreed += bytesFreed;
}

10
nix/libutil/util.cc

@ -305,7 +305,7 @@ void writeLine(int fd, string s)
}
static void _deletePath(const Path & path, unsigned long long & bytesFreed)
static void _deletePath(const Path & path, unsigned long long & bytesFreed, size_t linkThreshold)
{
checkInterrupt();
@ -324,7 +324,7 @@ static void _deletePath(const Path & path, unsigned long long & bytesFreed)
struct stat st = lstat(path);
#endif
if (!S_ISDIR(st.st_mode) && st.st_nlink == 1)
if (!S_ISDIR(st.st_mode) && st.st_nlink <= linkThreshold)
bytesFreed += st.st_size;
if (S_ISDIR(st.st_mode)) {
@ -335,7 +335,7 @@ static void _deletePath(const Path & path, unsigned long long & bytesFreed)
}
for (auto & i : readDirectory(path))
_deletePath(path + "/" + i.name, bytesFreed);
_deletePath(path + "/" + i.name, bytesFreed, linkThreshold);
}
#undef st_mode
#undef st_size
@ -353,12 +353,12 @@ void deletePath(const Path & path)
}
void deletePath(const Path & path, unsigned long long & bytesFreed)
void deletePath(const Path & path, unsigned long long & bytesFreed, size_t linkThreshold)
{
startNest(nest, lvlDebug,
format("recursively deleting path `%1%'") % path);
bytesFreed = 0;
_deletePath(path, bytesFreed);
_deletePath(path, bytesFreed, linkThreshold);
}

6
nix/libutil/util.hh

@ -94,10 +94,12 @@ void writeLine(int fd, string s);
/* Delete a path; i.e., in the case of a directory, it is deleted
recursively. Don't use this at home, kids. The second variant
returns the number of bytes and blocks freed. */
returns the number of bytes and blocks freed, and 'linkThreshold' denotes
the number of links under which a file is accounted for in 'bytesFreed'. */
void deletePath(const Path & path);
void deletePath(const Path & path, unsigned long long & bytesFreed);
void deletePath(const Path & path, unsigned long long & bytesFreed,
size_t linkThreshold = 1);
/* Create a temporary directory. */
Path createTempDir(const Path & tmpRoot = "", const Path & prefix = "nix",

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