* `nix-store --optimise': handle files with >= 32000 hard links.
(There can easily be more than 32000 occurrences of the empty file.)
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1 changed files with 31 additions and 6 deletions
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@ -4,6 +4,7 @@
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#include <sys/types.h>
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#include <sys/stat.h>
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#include <unistd.h>
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#include <errno.h>
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namespace nix {
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@ -22,6 +23,21 @@ static void makeWritable(const Path & path)
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}
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struct MakeReadOnly
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{
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Path path;
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MakeReadOnly(const Path & path) : path(path) { }
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~MakeReadOnly()
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{
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try {
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if (path != "") canonicalisePathMetaData(path, false);
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} catch (...) {
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ignoreException();
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}
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}
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};
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static void hashAndLink(bool dryRun, HashToPath & hashToPath,
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OptimiseStats & stats, const Path & path)
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{
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@ -82,20 +98,29 @@ static void hashAndLink(bool dryRun, HashToPath & hashToPath,
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mess with its permissions). */
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bool mustToggle = !isStorePath(path);
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if (mustToggle) makeWritable(dirOf(path));
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/* When we're done, make the directory read-only again and
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reset its timestamp back to 0. */
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MakeReadOnly makeReadOnly(mustToggle ? dirOf(path) : "");
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if (link(prevPath.first.c_str(), tempLink.c_str()) == -1)
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if (link(prevPath.first.c_str(), tempLink.c_str()) == -1) {
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if (errno == EMLINK) {
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/* Too many links to the same file (>= 32000 on
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most file systems). This is likely to happen
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with empty files. Just start over, creating
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links to the current file. */
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printMsg(lvlInfo, format("`%1%' has maximum number of links") % prevPath.first);
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hashToPath[hash] = std::pair<Path, ino_t>(path, st.st_ino);
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return;
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}
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throw SysError(format("cannot link `%1%' to `%2%'")
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% tempLink % prevPath.first);
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}
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/* Atomically replace the old file with the new hard link. */
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if (rename(tempLink.c_str(), path.c_str()) == -1)
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throw SysError(format("cannot rename `%1%' to `%2%'")
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% tempLink % path);
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/* Make the directory read-only again and reset its
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timestamp back to 0. */
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if (mustToggle) canonicalisePathMetaData(dirOf(path), false);
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} else
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printMsg(lvlTalkative, format("would link `%1%' to `%2%'") % path % prevPath.first);
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