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Remove durable_rename_excl()

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ccfbd92 has replaced all existing in-core callers of this function in
favor of durable_rename().  durable_rename_excl() is by nature unsafe on
crashes happening at the wrong time, so just remove it.

Author: Nathan Bossart
Reviewed-by: Robert Haas, Kyotaro Horiguchi, Michael Paquier
Discussion: https://postgr.es/m/20220407182954.GA1231544@nathanxps13
This commit is contained in:
Michael Paquier 2022-04-28 11:10:40 +09:00
parent ccfbd9287d
commit 2c902bbf19
3 changed files with 0 additions and 71 deletions
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63
src/backend/storage/file/fd.c
View File

@ -807,69 +807,6 @@ durable_unlink(const char *fname, int elevel)
return 0;
}
/*
* durable_rename_excl -- rename a file in a durable manner.
*
* Similar to durable_rename(), except that this routine tries (but does not
* guarantee) not to overwrite the target file.
*
* Note that a crash in an unfortunate moment can leave you with two links to
* the target file.
*
* Log errors with the caller specified severity.
*
* On Windows, using a hard link followed by unlink() causes concurrency
* issues, while a simple rename() does not cause that, so be careful when
* changing the logic of this routine.
*
* Returns 0 if the operation succeeded, -1 otherwise. Note that errno is not
* valid upon return.
*/
int
durable_rename_excl(const char *oldfile, const char *newfile, int elevel)
{
/*
* Ensure that, if we crash directly after the rename/link, a file with
* valid contents is moved into place.
*/
if (fsync_fname_ext(oldfile, false, false, elevel) != 0)
return -1;
#ifdef HAVE_WORKING_LINK
if (link(oldfile, newfile) < 0)
{
ereport(elevel,
(errcode_for_file_access(),
errmsg("could not link file \"%s\" to \"%s\": %m",
oldfile, newfile)));
return -1;
}
unlink(oldfile);
#else
if (rename(oldfile, newfile) < 0)
{
ereport(elevel,
(errcode_for_file_access(),
errmsg("could not rename file \"%s\" to \"%s\": %m",
oldfile, newfile)));
return -1;
}
#endif
/*
* Make change persistent in case of an OS crash, both the new entry and
* its parent directory need to be flushed.
*/
if (fsync_fname_ext(newfile, false, false, elevel) != 0)
return -1;
/* Same for parent directory */
if (fsync_parent_path(newfile, elevel) != 0)
return -1;
return 0;
}
/*
* InitFileAccess --- initialize this module during backend startup
*

7
src/include/pg_config_manual.h
View File

@ -163,13 +163,6 @@
#define USE_BARRIER_SMGRRELEASE
#endif
/*
* Define this if your operating system supports link()
*/
#if !defined(WIN32) && !defined(__CYGWIN__)
#define HAVE_WORKING_LINK 1
#endif
/*
* USE_POSIX_FADVISE controls whether Postgres will attempt to use the
* posix_fadvise() kernel call. Usually the automatic configure tests are

1
src/include/storage/fd.h
View File

@ -187,7 +187,6 @@ extern void fsync_fname(const char *fname, bool isdir);
extern int fsync_fname_ext(const char *fname, bool isdir, bool ignore_perm, int elevel);
extern int durable_rename(const char *oldfile, const char *newfile, int loglevel);
extern int durable_unlink(const char *fname, int loglevel);
extern int durable_rename_excl(const char *oldfile, const char *newfile, int loglevel);
extern void SyncDataDirectory(void);
extern int data_sync_elevel(int elevel);