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Adapt to the changes in the file locking API in libntech
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File locking in libntech is now a bit more abstract and
versatile.
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@vpodzime
vpodzime committed Oct 21, 2019
1 parent faab54a commit b5ee6a3
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Showing 4 changed files with 40 additions and 60 deletions.
32 changes: 14 additions & 18 deletions cf-check/repair.c
View file
Expand Up @@ -106,24 +106,22 @@ int repair_lmdb_file(const char *file, int fd_tstamp)
int ret;
char *dest_file = StringFormat("%s"REPAIR_FILE_EXTENSION, file);

/* Used to keep track of whether the repair timestamp file was opened
* locally. */
int local_fd_tstamp = -1;
FileLock lock = EMPTY_FILE_LOCK;
if (fd_tstamp == -1)
{
char *tstamp_file = StringFormat("%s.repaired", file);
fd_tstamp = safe_open(tstamp_file, O_CREAT|O_RDWR);
int lock_ret = ExclusiveFileLockPath(&lock, tstamp_file, true); /* wait=true */
free(tstamp_file);
local_fd_tstamp = fd_tstamp;
}
if (!ExclusiveLockFileCheck(fd_tstamp) && ExclusiveLockFile(fd_tstamp, true) == -1)
{
/* Should never happen because we tried to wait for the lock. */
Log(LOG_LEVEL_ERR,
"Failed to acquire lock for the '%s' DB repair timestamp file",
file);
ret = -1;
goto cleanup;
if (lock_ret < 0)
{
/* Should never happen because we tried to wait for the lock. */
Log(LOG_LEVEL_ERR,
"Failed to acquire lock for the '%s' DB repair timestamp file",
file);
ret = -1;
goto cleanup;
}
fd_tstamp = lock.fd;
}
pid_t child_pid = fork();
if (child_pid == 0)
Expand Down Expand Up @@ -205,11 +203,9 @@ int repair_lmdb_file(const char *file, int fd_tstamp)
}
cleanup:
free(dest_file);
if (local_fd_tstamp != -1)
if (lock.fd != -1)
{
/* Also releases file locks on the timestamp file if we opened it
* locally. */
close(local_fd_tstamp);
ExclusiveFileUnlock(&lock, true); /* close=true */
}
return ret;
}
Expand Down
2 changes: 1 addition & 1 deletion libntech
Submodule libntech updated from eb05bb to d847a2
38 changes: 12 additions & 26 deletions libpromises/dbm_api.c
View file
Expand Up @@ -37,8 +37,8 @@
#include <time.h> /* time() */


static int DBPathLock(const char *filename);
static void DBPathUnLock(int fd);
static bool DBPathLock(FileLock *lock, const char *filename);
static void DBPathUnLock(FileLock *lock);
static void DBPathMoveBroken(const char *filename);

struct DBHandle_
Expand Down Expand Up @@ -379,9 +379,8 @@ bool OpenDBInstance(DBHandle **dbp, dbid id, DBHandle *handle)
}
if (handle->refcount == 0)
{
int lock_fd = DBPathLock(handle->filename);

if(lock_fd != -1)
FileLock lock = EMPTY_FILE_LOCK;
if (DBPathLock(&lock, handle->filename))
{
handle->open_tstamp = time(NULL);
handle->priv = DBPrivOpenDB(handle->filename, id);
Expand All @@ -396,7 +395,7 @@ bool OpenDBInstance(DBHandle **dbp, dbid id, DBHandle *handle)
}
}

DBPathUnLock(lock_fd);
DBPathUnLock(&lock);
}

if (handle->priv)
Expand Down Expand Up @@ -613,42 +612,29 @@ bool DeleteDBCursor(DBCursor *cursor)
return true;
}

static int DBPathLock(const char *filename)
static bool DBPathLock(FileLock *lock, const char *filename)
{
char *filename_lock;
if (xasprintf(&filename_lock, "%s.lock", filename) == -1)
{
ProgrammingError("Unable to construct lock database filename for file %s", filename);
}

int fd = open(filename_lock, O_CREAT | O_RDWR, 0666);

if(fd == -1)
{
Log(LOG_LEVEL_ERR, "Unable to open database lock file '%s'. (flock: %s)", filename_lock, GetErrorStr());
free(filename_lock);
return -1;
}

if (ExclusiveLockFile(fd, true) == -1)
if (ExclusiveFileLockPath(lock, filename_lock, true) != 0)
{
Log(LOG_LEVEL_ERR, "Unable to lock database lock file '%s'. (fcntl(F_SETLK): %s)", filename_lock, GetErrorStr());
Log(LOG_LEVEL_ERR, "Unable to lock database lock file '%s'.", filename_lock);
free(filename_lock);
close(fd);
return -1;
return false;
}

free(filename_lock);

return fd;
return true;
}

static void DBPathUnLock(int fd)
static void DBPathUnLock(FileLock *lock)
{
if(ExclusiveUnlockFile(fd) != 0)
{
Log(LOG_LEVEL_ERR, "Could not close db lock-file. (close: %s)", GetErrorStr());
}
ExclusiveFileUnlock(lock, true);
}

static void DBPathMoveBroken(const char *filename)
Expand Down
28 changes: 13 additions & 15 deletions libpromises/dbm_lmdb.c
View file
Expand Up @@ -311,6 +311,8 @@ static void HandleLMDBCorruption(MDB_env *env, const char *msg)

exit(EC_CORRUPTION_REPAIR_FAILED);
}
FileLock tstamp_lock = { .fd = fd_tstamp };

int fd_db_lock = safe_open(db_lock_file, O_CREAT|O_RDWR);
if (fd_db_lock == -1)
{
Expand All @@ -323,20 +325,17 @@ static void HandleLMDBCorruption(MDB_env *env, const char *msg)

exit(EC_CORRUPTION_REPAIR_FAILED);
}
FileLock db_lock = { .fd = fd_db_lock };

int ret;
bool handle_corruption = true;

/* Make sure we are not holding the DB's lock (potentially needed by some
* other process for the repair) to avoid deadlocks. */
if (ExclusiveLockFileCheck(fd_db_lock))
{
Log(LOG_LEVEL_DEBUG, "Releasing lock on the '%s' DB", lmdb_file);
ExclusiveUnlockFile(fd_db_lock); /* closes fd_db_lock (TODO: fix) */
fd_db_lock = safe_open(db_lock_file, O_CREAT|O_RDWR);
}
Log(LOG_LEVEL_DEBUG, "Releasing lock on the '%s' DB", lmdb_file);
ExclusiveFileUnlock(&db_lock, false); /* close=false */

ret = SharedLockFile(fd_tstamp, true);
ret = SharedFileLock(&tstamp_lock, true);
if (ret == 0)
{
if (RepairedAfterOpen(lmdb_file, fd_tstamp))
Expand All @@ -346,8 +345,7 @@ static void HandleLMDBCorruption(MDB_env *env, const char *msg)
* it would just open the new (repaired) LMDB file. */
handle_corruption = false;
}
SharedUnlockFile(fd_tstamp); /* closes fd_tstamp (TODO: fix) */
fd_tstamp = safe_open(tstamp_file, O_CREAT|O_RDWR);
SharedFileUnlock(&tstamp_lock, false);
}
else
{
Expand Down Expand Up @@ -376,8 +374,8 @@ static void HandleLMDBCorruption(MDB_env *env, const char *msg)
* contents of the timestamp file again below, while holding the EXCLUSIVE
* lock. */

ret = ExclusiveLockFile(fd_tstamp, true);
if (ret == -1)
ret = ExclusiveFileLock(&tstamp_lock, true);
if (ret != 0)
{
/* should never happen (we tried to wait), but if it does, just
* terminate because doing the repair without the lock could be
Expand All @@ -399,7 +397,7 @@ static void HandleLMDBCorruption(MDB_env *env, const char *msg)

/* 1. Acquire the lock for the DB to prevent more processes trying to use
* it while it is corrupted (wait till the lock is available). */
while (ExclusiveLockFile(fd_db_lock, false) == -1)
while (ExclusiveFileLock(&db_lock, false) == -1)
{
/* busy wait to do the logging */
Log(LOG_LEVEL_INFO, "Waiting for the lock on the '%s' DB",
Expand Down Expand Up @@ -443,14 +441,14 @@ static void HandleLMDBCorruption(MDB_env *env, const char *msg)
/* 4. Make the repaired DB available for others. Also release the locks
* in the opposite order in which they were acquired to avoid
* deadlocks. */
if (ExclusiveUnlockFile(fd_db_lock) != 0)
if (ExclusiveFileUnlock(&db_lock, true) != 0)
{
Log(LOG_LEVEL_ERR, "Failed to release the acquired lock for '%s'",
db_lock_file);
}

/* 5. Signal that the repair is done (also closes fd_tstamp). */
if (ExclusiveUnlockFile(fd_tstamp) != 0)
if (ExclusiveFileUnlock(&tstamp_lock, true) != 0)
{
Log(LOG_LEVEL_ERR, "Failed to release the acquired lock for '%s'",
tstamp_file);
Expand All @@ -460,7 +458,7 @@ static void HandleLMDBCorruption(MDB_env *env, const char *msg)
free(db_lock_file);
free(tstamp_file);
/* fd_db_lock and fd_tstamp are already closed by the calls to
* ExclusiveUnlockFile above. */
* ExclusiveFileUnlock above. */

if (repair_successful)
{
Expand Down

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