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Avoid leaking FDs after an fsync failure.

Browse Source 
Fixes errors introduced in commit bc34223bc, as detected by Coverity.

In passing, report ENOSPC for a short write while padding a new wal file in
open_walfile, make certain that close_walfile closes walfile in all cases,
and improve a couple of comments.

Michael Paquier and Tom Lane
This commit is contained in:
Tom Lane 2016-10-02 12:33:46 -04:00
parent 3b90e38c5d
commit 728ceba938
2 changed files with 43 additions and 14 deletions
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56
src/bin/pg_basebackup/receivelog.c
View File

@ -86,8 +86,11 @@ mark_file_as_archived(const char *basedir, const char *fname, bool do_sync)
/*
* Open a new WAL file in the specified directory.
*
* The file will be padded to 16Mb with zeroes. The base filename (without
* partial_suffix) is stored in current_walfile_name.
* Returns true if OK; on failure, returns false after printing an error msg.
* On success, 'walfile' is set to the FD for the file, and the base filename
* (without partial_suffix) is stored in 'current_walfile_name'.
*
* The file will be padded to 16Mb with zeroes.
*/
static bool
open_walfile(StreamCtl *stream, XLogRecPtr startpoint)
@ -127,18 +130,23 @@ open_walfile(StreamCtl *stream, XLogRecPtr startpoint)
}
if (statbuf.st_size == XLogSegSize)
{
/* File is open and ready to use */
walfile = f;
/*
* fsync, in case of a previous crash between padding and fsyncing the
* file.
*/
if (stream->do_sync && fsync_fname(fn, false, progname) != 0)
return false;
if (stream->do_sync && fsync_parent_path(fn, progname) != 0)
return false;
if (stream->do_sync)
{
if (fsync_fname(fn, false, progname) != 0 ||
fsync_parent_path(fn, progname) != 0)
{
/* error already printed */
close(f);
return false;
}
}
/* File is open and ready to use */
walfile = f;
return true;
}
if (statbuf.st_size != 0)
@ -150,12 +158,20 @@ open_walfile(StreamCtl *stream, XLogRecPtr startpoint)
return false;
}
/* New, empty, file. So pad it to 16Mb with zeroes */
/*
* New, empty, file. So pad it to 16Mb with zeroes. If we fail partway
* through padding, we should attempt to unlink the file on failure, so as
* not to leave behind a partially-filled file.
*/
zerobuf = pg_malloc0(XLOG_BLCKSZ);
for (bytes = 0; bytes < XLogSegSize; bytes += XLOG_BLCKSZ)
{
errno = 0;
if (write(f, zerobuf, XLOG_BLCKSZ) != XLOG_BLCKSZ)
{
/* if write didn't set errno, assume problem is no disk space */
if (errno == 0)
errno = ENOSPC;
fprintf(stderr,
_("%s: could not pad transaction log file \"%s\": %s\n"),
progname, fn, strerror(errno));
@ -173,10 +189,16 @@ open_walfile(StreamCtl *stream, XLogRecPtr startpoint)
* using synchronous mode, where the file is modified and fsynced
* in-place, without a directory fsync.
*/
if (stream->do_sync && fsync_fname(fn, false, progname) != 0)
return false;
if (stream->do_sync && fsync_parent_path(fn, progname) != 0)
return false;
if (stream->do_sync)
{
if (fsync_fname(fn, false, progname) != 0 ||
fsync_parent_path(fn, progname) != 0)
{
/* error already printed */
close(f);
return false;
}
}
if (lseek(f, SEEK_SET, 0) != 0)
{
@ -186,6 +208,8 @@ open_walfile(StreamCtl *stream, XLogRecPtr startpoint)
close(f);
return false;
}
/* File is open and ready to use */
walfile = f;
return true;
}
@ -209,6 +233,8 @@ close_walfile(StreamCtl *stream, XLogRecPtr pos)
fprintf(stderr,
_("%s: could not determine seek position in file \"%s\": %s\n"),
progname, current_walfile_name, strerror(errno));
close(walfile);
walfile = -1;
return false;
}
@ -216,6 +242,8 @@ close_walfile(StreamCtl *stream, XLogRecPtr pos)
{
fprintf(stderr, _("%s: could not fsync file \"%s\": %s\n"),
progname, current_walfile_name, strerror(errno));
close(walfile);
walfile = -1;
return false;
}

1
src/common/file_utils.c
View File

@ -273,6 +273,7 @@ fsync_fname(const char *fname, bool isdir, const char *progname)
{
fprintf(stderr, _("%s: could not fsync file \"%s\": %s\n"),
progname, fname, strerror(errno));
(void) close(fd);
return -1;
}