X-Git-Url: https://git.ozlabs.org/?p=ccan;a=blobdiff_plain;f=ccan%2Ftdb2%2Fio.c;h=866ff085bb5e87b6e3463e016aa7202e800c4708;hp=56ccfcba67b7ab2dac531f5d3cf9a08d22644ca4;hb=78bb1258f9e67f3052488c6168c40f94a3258cca;hpb=b44978e1499a61c3d91d93dbd7c45b6fc45b1778

diff --git a/ccan/tdb2/io.c b/ccan/tdb2/io.c
index 56ccfcba..866ff085 100644
--- a/ccan/tdb2/io.c
+++ b/ccan/tdb2/io.c
@@ -1,4 +1,4 @@
- /* 
+ /*
    Unix SMB/CIFS implementation.
 
    trivial database library
@@ -56,21 +56,22 @@ void tdb_mmap(struct tdb_context *tdb)
 	 */
 	if (tdb->map_ptr == MAP_FAILED) {
 		tdb->map_ptr = NULL;
-		tdb->log(tdb, TDB_DEBUG_WARNING, tdb->log_priv,
-			 "tdb_mmap failed for size %lld (%s)\n", 
-			 (long long)tdb->map_size, strerror(errno));
+		tdb_logerr(tdb, TDB_SUCCESS, TDB_LOG_WARNING,
+			   "tdb_mmap failed for size %lld (%s)",
+			   (long long)tdb->map_size, strerror(errno));
 	}
 }
 
 /* check for an out of bounds access - if it is out of bounds then
    see if the database has been expanded by someone else and expand
-   if necessary 
+   if necessary
    note that "len" is the minimum length needed for the db
 */
-static int tdb_oob(struct tdb_context *tdb, tdb_off_t len, bool probe)
+static enum TDB_ERROR tdb_oob(struct tdb_context *tdb, tdb_off_t len,
+			      bool probe)
 {
 	struct stat st;
-	int ret;
+	enum TDB_ERROR ecode;
 
 	/* We can't hold pointers during this: we could unmap! */
 	assert(!tdb->direct_access
@@ -81,38 +82,36 @@ static int tdb_oob(struct tdb_context *tdb, tdb_off_t len, bool probe)
 		return 0;
 	if (tdb->flags & TDB_INTERNAL) {
 		if (!probe) {
-			/* Ensure ecode is set for log fn. */
-			tdb->ecode = TDB_ERR_IO;
-			tdb->log(tdb, TDB_DEBUG_FATAL, tdb->log_priv,
+			tdb_logerr(tdb, TDB_ERR_IO, TDB_LOG_ERROR,
 				 "tdb_oob len %lld beyond internal"
-				 " malloc size %lld\n",
+				 " malloc size %lld",
 				 (long long)len,
 				 (long long)tdb->map_size);
 		}
-		return -1;
+		return TDB_ERR_IO;
 	}
 
-	if (tdb_lock_expand(tdb, F_RDLCK) != 0)
-		return -1;
+	ecode = tdb_lock_expand(tdb, F_RDLCK);
+	if (ecode != TDB_SUCCESS) {
+		return ecode;
+	}
 
-	ret = fstat(tdb->fd, &st);
+	if (fstat(tdb->fd, &st) != 0) {
+		tdb_logerr(tdb, TDB_ERR_IO, TDB_LOG_ERROR,
+			   "Failed to fstat file: %s", strerror(errno));
+		tdb_unlock_expand(tdb, F_RDLCK);
+		return TDB_ERR_IO;
+	}
 
 	tdb_unlock_expand(tdb, F_RDLCK);
 
-	if (ret == -1) {
-		tdb->ecode = TDB_ERR_IO;
-		return -1;
-	}
-
 	if (st.st_size < (size_t)len) {
 		if (!probe) {
-			/* Ensure ecode is set for log fn. */
-			tdb->ecode = TDB_ERR_IO;
-			tdb->log(tdb, TDB_DEBUG_FATAL, tdb->log_priv,
-				 "tdb_oob len %lld beyond eof at %lld\n",
-				 (long long)len, (long long)st.st_size);
+			tdb_logerr(tdb, TDB_ERR_IO, TDB_LOG_ERROR,
+				   "tdb_oob len %zu beyond eof at %zu",
+				   (size_t)len, st.st_size);
 		}
-		return -1;
+		return TDB_ERR_IO;
 	}
 
 	/* Unmap, update size, remap */
@@ -120,7 +119,7 @@ static int tdb_oob(struct tdb_context *tdb, tdb_off_t len, bool probe)
 
 	tdb->map_size = st.st_size;
 	tdb_mmap(tdb);
-	return 0;
+	return TDB_SUCCESS;
 }
 
 /* Endian conversion: we only ever deal with 8 byte quantities */
@@ -134,6 +133,7 @@ void *tdb_convert(const struct tdb_context *tdb, void *buf, tdb_len_t size)
 	return buf;
 }
 
+/* Return first non-zero offset in offset array, or end, or -ve error. */
 /* FIXME: Return the off? */
 uint64_t tdb_find_nonzero_off(struct tdb_context *tdb,
 			      tdb_off_t base, uint64_t start, uint64_t end)
@@ -144,8 +144,9 @@ uint64_t tdb_find_nonzero_off(struct tdb_context *tdb,
 	/* Zero vs non-zero is the same unconverted: minor optimization. */
 	val = tdb_access_read(tdb, base + start * sizeof(tdb_off_t),
 			      (end - start) * sizeof(tdb_off_t), false);
-	if (!val)
-		return end;
+	if (TDB_PTR_IS_ERR(val)) {
+		return TDB_PTR_ERR(val);
+	}
 
 	for (i = 0; i < (end - start); i++) {
 		if (val[i])
@@ -155,7 +156,7 @@ uint64_t tdb_find_nonzero_off(struct tdb_context *tdb,
 	return start + i;
 }
 
-/* Return first zero offset in num offset array, or num. */
+/* Return first zero offset in num offset array, or num, or -ve error. */
 uint64_t tdb_find_zero_off(struct tdb_context *tdb, tdb_off_t off,
 			   uint64_t num)
 {
@@ -164,8 +165,9 @@ uint64_t tdb_find_zero_off(struct tdb_context *tdb, tdb_off_t off,
 
 	/* Zero vs non-zero is the same unconverted: minor optimization. */
 	val = tdb_access_read(tdb, off, num * sizeof(tdb_off_t), false);
-	if (!val)
-		return num;
+	if (TDB_PTR_IS_ERR(val)) {
+		return TDB_PTR_ERR(val);
+	}
 
 	for (i = 0; i < num; i++) {
 		if (!val[i])
@@ -175,202 +177,163 @@ uint64_t tdb_find_zero_off(struct tdb_context *tdb, tdb_off_t off,
 	return i;
 }
 
-int zero_out(struct tdb_context *tdb, tdb_off_t off, tdb_len_t len)
+enum TDB_ERROR zero_out(struct tdb_context *tdb, tdb_off_t off, tdb_len_t len)
 {
 	char buf[8192] = { 0 };
-	void *p = tdb->methods->direct(tdb, off, len);
+	void *p = tdb->methods->direct(tdb, off, len, true);
+	enum TDB_ERROR ecode = TDB_SUCCESS;
 
-	if (tdb->read_only) {
-		tdb->ecode = TDB_ERR_RDONLY;
-		return -1;
+	assert(!tdb->read_only);
+	if (TDB_PTR_IS_ERR(p)) {
+		return TDB_PTR_ERR(p);
 	}
-
 	if (p) {
 		memset(p, 0, len);
-		return 0;
+		return ecode;
 	}
 	while (len) {
 		unsigned todo = len < sizeof(buf) ? len : sizeof(buf);
-		if (tdb->methods->write(tdb, off, buf, todo) == -1)
-			return -1;
+		ecode = tdb->methods->twrite(tdb, off, buf, todo);
+		if (ecode != TDB_SUCCESS) {
+			break;
+		}
 		len -= todo;
 		off += todo;
 	}
-	return 0;
+	return ecode;
 }
 
 tdb_off_t tdb_read_off(struct tdb_context *tdb, tdb_off_t off)
 {
 	tdb_off_t ret;
+	enum TDB_ERROR ecode;
 
 	if (likely(!(tdb->flags & TDB_CONVERT))) {
-		tdb_off_t *p = tdb->methods->direct(tdb, off, sizeof(*p));
+		tdb_off_t *p = tdb->methods->direct(tdb, off, sizeof(*p),
+						    false);
+		if (TDB_PTR_IS_ERR(p)) {
+			return TDB_PTR_ERR(p);
+		}
 		if (p)
 			return *p;
 	}
 
-	if (tdb_read_convert(tdb, off, &ret, sizeof(ret)) == -1)
-		return TDB_OFF_ERR;
-	return ret;
-}
-
-/* Even on files, we can get partial writes due to signals. */
-bool tdb_pwrite_all(int fd, const void *buf, size_t len, tdb_off_t off)
-{
-	while (len) {
-		ssize_t ret;
-		ret = pwrite(fd, buf, len, off);
-		if (ret < 0)
-			return false;
-		if (ret == 0) {
-			errno = ENOSPC;
-			return false;
-		}
-		buf = (char *)buf + ret;
-		off += ret;
-		len -= ret;
-	}
-	return true;
-}
-
-/* Even on files, we can get partial reads due to signals. */
-bool tdb_pread_all(int fd, void *buf, size_t len, tdb_off_t off)
-{
-	while (len) {
-		ssize_t ret;
-		ret = pread(fd, buf, len, off);
-		if (ret < 0)
-			return false;
-		if (ret == 0) {
-			/* ETOOSHORT? */
-			errno = EWOULDBLOCK;
-			return false;
-		}
-		buf = (char *)buf + ret;
-		off += ret;
-		len -= ret;
+	ecode = tdb_read_convert(tdb, off, &ret, sizeof(ret));
+	if (ecode != TDB_SUCCESS) {
+		return ecode;
 	}
-	return true;
-}
-
-bool tdb_read_all(int fd, void *buf, size_t len)
-{
-	while (len) {
-		ssize_t ret;
-		ret = read(fd, buf, len);
-		if (ret < 0)
-			return false;
-		if (ret == 0) {
-			/* ETOOSHORT? */
-			errno = EWOULDBLOCK;
-			return false;
-		}
-		buf = (char *)buf + ret;
-		len -= ret;
-	}
-	return true;
+	return ret;
 }
 
 /* write a lump of data at a specified offset */
-static int tdb_write(struct tdb_context *tdb, tdb_off_t off, 
-		     const void *buf, tdb_len_t len)
+static enum TDB_ERROR tdb_write(struct tdb_context *tdb, tdb_off_t off,
+				const void *buf, tdb_len_t len)
 {
-	if (len == 0) {
-		return 0;
-	}
+	enum TDB_ERROR ecode;
 
 	if (tdb->read_only) {
-		tdb->ecode = TDB_ERR_RDONLY;
-		return -1;
+		return tdb_logerr(tdb, TDB_ERR_RDONLY, TDB_LOG_USE_ERROR,
+				  "Write to read-only database");
 	}
 
-	if (tdb->methods->oob(tdb, off + len, 0) != 0)
-		return -1;
+	ecode = tdb->methods->oob(tdb, off + len, 0);
+	if (ecode != TDB_SUCCESS) {
+		return ecode;
+	}
 
 	if (tdb->map_ptr) {
 		memcpy(off + (char *)tdb->map_ptr, buf, len);
 	} else {
-		if (!tdb_pwrite_all(tdb->fd, buf, len, off)) {
-			tdb->ecode = TDB_ERR_IO;
-			tdb->log(tdb, TDB_DEBUG_FATAL, tdb->log_priv,
-				 "tdb_write failed at %llu len=%llu (%s)\n",
-				 (long long)off, (long long)len,
-				 strerror(errno));
-			return -1;
+		ssize_t ret;
+		ret = pwrite(tdb->fd, buf, len, off);
+		if (ret < len) {
+			/* This shouldn't happen: we avoid sparse files. */
+			if (ret >= 0)
+				errno = ENOSPC;
+
+			return tdb_logerr(tdb, TDB_ERR_IO, TDB_LOG_ERROR,
+					  "tdb_write: %zi at %zu len=%zu (%s)",
+					  ret, (size_t)off, (size_t)len,
+					  strerror(errno));
 		}
 	}
-	return 0;
+	return TDB_SUCCESS;
 }
 
 /* read a lump of data at a specified offset */
-static int tdb_read(struct tdb_context *tdb, tdb_off_t off, void *buf,
-		    tdb_len_t len)
+static enum TDB_ERROR tdb_read(struct tdb_context *tdb, tdb_off_t off,
+			       void *buf, tdb_len_t len)
 {
-	if (tdb->methods->oob(tdb, off + len, 0) != 0) {
-		return -1;
+	enum TDB_ERROR ecode;
+
+	ecode = tdb->methods->oob(tdb, off + len, 0);
+	if (ecode != TDB_SUCCESS) {
+		return ecode;
 	}
 
 	if (tdb->map_ptr) {
 		memcpy(buf, off + (char *)tdb->map_ptr, len);
 	} else {
-		if (!tdb_pread_all(tdb->fd, buf, len, off)) {
-			/* Ensure ecode is set for log fn. */
-			tdb->ecode = TDB_ERR_IO;
-			tdb->log(tdb, TDB_DEBUG_FATAL, tdb->log_priv,
-				 "tdb_read failed at %lld "
-				 "len=%lld (%s) map_size=%lld\n",
-				 (long long)off, (long long)len,
-				 strerror(errno),
-				 (long long)tdb->map_size);
-			return -1;
+		ssize_t r = pread(tdb->fd, buf, len, off);
+		if (r != len) {
+			return tdb_logerr(tdb, TDB_ERR_IO, TDB_LOG_ERROR,
+					  "tdb_read failed with %zi at %zu "
+					  "len=%zu (%s) map_size=%zu",
+					  r, (size_t)off, (size_t)len,
+					  strerror(errno),
+					  (size_t)tdb->map_size);
 		}
 	}
-	return 0;
+	return TDB_SUCCESS;
 }
 
-int tdb_write_convert(struct tdb_context *tdb, tdb_off_t off,
-		      const void *rec, size_t len)
+enum TDB_ERROR tdb_write_convert(struct tdb_context *tdb, tdb_off_t off,
+				 const void *rec, size_t len)
 {
-	int ret;
+	enum TDB_ERROR ecode;
+
 	if (unlikely((tdb->flags & TDB_CONVERT))) {
 		void *conv = malloc(len);
 		if (!conv) {
-			tdb->ecode = TDB_ERR_OOM;
-			tdb->log(tdb, TDB_DEBUG_FATAL, tdb->log_priv,
-				 "tdb_write: no memory converting %zu bytes\n",
-				 len);
-			return -1;
+			return tdb_logerr(tdb, TDB_ERR_OOM, TDB_LOG_ERROR,
+					  "tdb_write: no memory converting"
+					  " %zu bytes", len);
 		}
 		memcpy(conv, rec, len);
-		ret = tdb->methods->write(tdb, off,
-					  tdb_convert(tdb, conv, len), len);
+		ecode = tdb->methods->twrite(tdb, off,
+					   tdb_convert(tdb, conv, len), len);
 		free(conv);
-	} else
-		ret = tdb->methods->write(tdb, off, rec, len);
-
-	return ret;
+	} else {
+		ecode = tdb->methods->twrite(tdb, off, rec, len);
+	}
+	return ecode;
 }
 
-int tdb_read_convert(struct tdb_context *tdb, tdb_off_t off,
-		      void *rec, size_t len)
+enum TDB_ERROR tdb_read_convert(struct tdb_context *tdb, tdb_off_t off,
+				void *rec, size_t len)
 {
-	int ret = tdb->methods->read(tdb, off, rec, len);
+	enum TDB_ERROR ecode = tdb->methods->tread(tdb, off, rec, len);
 	tdb_convert(tdb, rec, len);
-	return ret;
+	return ecode;
 }
 
-int tdb_write_off(struct tdb_context *tdb, tdb_off_t off, tdb_off_t val)
+enum TDB_ERROR tdb_write_off(struct tdb_context *tdb,
+			     tdb_off_t off, tdb_off_t val)
 {
 	if (tdb->read_only) {
-		tdb->ecode = TDB_ERR_RDONLY;
-		return -1;
+		return tdb_logerr(tdb, TDB_ERR_RDONLY, TDB_LOG_USE_ERROR,
+				  "Write to read-only database");
 	}
 
 	if (likely(!(tdb->flags & TDB_CONVERT))) {
-		tdb_off_t *p = tdb->methods->direct(tdb, off, sizeof(*p));
+		tdb_off_t *p = tdb->methods->direct(tdb, off, sizeof(*p),
+						    true);
+		if (TDB_PTR_IS_ERR(p)) {
+			return TDB_PTR_ERR(p);
+		}
 		if (p) {
 			*p = val;
-			return 0;
+			return TDB_SUCCESS;
 		}
 	}
 	return tdb_write_convert(tdb, off, &val, sizeof(val));
@@ -380,17 +343,21 @@ static void *_tdb_alloc_read(struct tdb_context *tdb, tdb_off_t offset,
 			     tdb_len_t len, unsigned int prefix)
 {
 	void *buf;
+	enum TDB_ERROR ecode;
 
 	/* some systems don't like zero length malloc */
 	buf = malloc(prefix + len ? prefix + len : 1);
-	if (unlikely(!buf)) {
-		tdb->ecode = TDB_ERR_OOM;
-		tdb->log(tdb, TDB_DEBUG_ERROR, tdb->log_priv,
-			 "tdb_alloc_read malloc failed len=%lld\n",
-			 (long long)prefix + len);
-	} else if (unlikely(tdb->methods->read(tdb, offset, buf+prefix, len))) {
-		free(buf);
-		buf = NULL;
+	if (!buf) {
+		tdb_logerr(tdb, TDB_ERR_OOM, TDB_LOG_USE_ERROR,
+			   "tdb_alloc_read malloc failed len=%zu",
+			   (size_t)(prefix + len));
+		return TDB_ERR_PTR(TDB_ERR_OOM);
+	} else {
+		ecode = tdb->methods->tread(tdb, offset, buf+prefix, len);
+		if (unlikely(ecode != TDB_SUCCESS)) {
+			free(buf);
+			return TDB_ERR_PTR(ecode);
+		}
 	}
 	return buf;
 }
@@ -401,41 +368,47 @@ void *tdb_alloc_read(struct tdb_context *tdb, tdb_off_t offset, tdb_len_t len)
 	return _tdb_alloc_read(tdb, offset, len, 0);
 }
 
-static int fill(struct tdb_context *tdb,
-		const void *buf, size_t size,
-		tdb_off_t off, tdb_len_t len)
+static enum TDB_ERROR fill(struct tdb_context *tdb,
+			   const void *buf, size_t size,
+			   tdb_off_t off, tdb_len_t len)
 {
 	while (len) {
 		size_t n = len > size ? size : len;
-
-		if (!tdb_pwrite_all(tdb->fd, buf, n, off)) {
-			tdb->ecode = TDB_ERR_IO;
-			tdb->log(tdb, TDB_DEBUG_FATAL, tdb->log_priv,
-				 "fill write failed: giving up!\n");
-			return -1;
+		ssize_t ret = pwrite(tdb->fd, buf, n, off);
+		if (ret < n) {
+			if (ret >= 0)
+				errno = ENOSPC;
+
+			return tdb_logerr(tdb, TDB_ERR_IO, TDB_LOG_ERROR,
+					  "fill failed:"
+					  " %zi at %zu len=%zu (%s)",
+					  ret, (size_t)off, (size_t)len,
+					  strerror(errno));
 		}
 		len -= n;
 		off += n;
 	}
-	return 0;
+	return TDB_SUCCESS;
 }
 
 /* expand a file.  we prefer to use ftruncate, as that is what posix
   says to use for mmap expansion */
-static int tdb_expand_file(struct tdb_context *tdb, tdb_len_t addition)
+static enum TDB_ERROR tdb_expand_file(struct tdb_context *tdb,
+				      tdb_len_t addition)
 {
 	char buf[8192];
+	enum TDB_ERROR ecode;
 
 	if (tdb->read_only) {
-		tdb->ecode = TDB_ERR_RDONLY;
-		return -1;
+		return tdb_logerr(tdb, TDB_ERR_RDONLY, TDB_LOG_USE_ERROR,
+				  "Expand on read-only database");
 	}
 
 	if (tdb->flags & TDB_INTERNAL) {
 		char *new = realloc(tdb->map_ptr, tdb->map_size + addition);
 		if (!new) {
-			tdb->ecode = TDB_ERR_OOM;
-			return -1;
+			return tdb_logerr(tdb, TDB_ERR_OOM, TDB_LOG_ERROR,
+					  "No memory to expand database");
 		}
 		tdb->map_ptr = new;
 		tdb->map_size += addition;
@@ -452,36 +425,38 @@ static int tdb_expand_file(struct tdb_context *tdb, tdb_len_t addition)
 		   file isn't sparse, which would be very bad if we ran out of
 		   disk. This must be done with write, not via mmap */
 		memset(buf, 0x43, sizeof(buf));
-		if (0 || fill(tdb, buf, sizeof(buf), tdb->map_size, addition) == -1)
-			return -1;
+		ecode = fill(tdb, buf, sizeof(buf), tdb->map_size, addition);
+		if (ecode != TDB_SUCCESS)
+			return ecode;
 		tdb->map_size += addition;
 		tdb_mmap(tdb);
 	}
-	return 0;
+	return TDB_SUCCESS;
 }
 
-/* This is only neded for tdb_access_commit, but used everywhere to simplify. */
-struct tdb_access_hdr {
-	tdb_off_t off;
-	tdb_len_t len;
-	bool convert;
-};
-
 const void *tdb_access_read(struct tdb_context *tdb,
 			    tdb_off_t off, tdb_len_t len, bool convert)
 {
-	const void *ret = NULL;	
+	const void *ret = NULL;
 
-	if (likely(!(tdb->flags & TDB_CONVERT)))
-		ret = tdb->methods->direct(tdb, off, len);
+	if (likely(!(tdb->flags & TDB_CONVERT))) {
+		ret = tdb->methods->direct(tdb, off, len, false);
 
+		if (TDB_PTR_IS_ERR(ret)) {
+			return ret;
+		}
+	}
 	if (!ret) {
 		struct tdb_access_hdr *hdr;
 		hdr = _tdb_alloc_read(tdb, off, len, sizeof(*hdr));
-		if (hdr) {
-			ret = hdr + 1;
-			if (convert)
-				tdb_convert(tdb, (void *)ret, len);
+		if (TDB_PTR_IS_ERR(hdr)) {
+			return hdr;
+		}
+		hdr->next = tdb->access;
+		tdb->access = hdr;
+		ret = hdr + 1;
+		if (convert) {
+			tdb_convert(tdb, (void *)ret, len);
 		}
 	} else
 		tdb->direct_access++;
@@ -495,80 +470,101 @@ void *tdb_access_write(struct tdb_context *tdb,
 	void *ret = NULL;
 
 	if (tdb->read_only) {
-		tdb->ecode = TDB_ERR_RDONLY;
-		return NULL;
+		tdb_logerr(tdb, TDB_ERR_RDONLY, TDB_LOG_USE_ERROR,
+			   "Write to read-only database");
+		return TDB_ERR_PTR(TDB_ERR_RDONLY);
 	}
 
-	if (likely(!(tdb->flags & TDB_CONVERT)))
-		ret = tdb->methods->direct(tdb, off, len);
+	if (likely(!(tdb->flags & TDB_CONVERT))) {
+		ret = tdb->methods->direct(tdb, off, len, true);
+
+		if (TDB_PTR_IS_ERR(ret)) {
+			return ret;
+		}
+	}
 
 	if (!ret) {
 		struct tdb_access_hdr *hdr;
 		hdr = _tdb_alloc_read(tdb, off, len, sizeof(*hdr));
-		if (hdr) {
-			hdr->off = off;
-			hdr->len = len;
-			hdr->convert = convert;
-			ret = hdr + 1;
-			if (convert)
-				tdb_convert(tdb, (void *)ret, len);
+		if (TDB_PTR_IS_ERR(hdr)) {
+			return hdr;
 		}
+		hdr->next = tdb->access;
+		tdb->access = hdr;
+		hdr->off = off;
+		hdr->len = len;
+		hdr->convert = convert;
+		ret = hdr + 1;
+		if (convert)
+			tdb_convert(tdb, (void *)ret, len);
 	} else
 		tdb->direct_access++;
 
 	return ret;
 }
 
-bool is_direct(const struct tdb_context *tdb, const void *p)
+static struct tdb_access_hdr **find_hdr(struct tdb_context *tdb, const void *p)
 {
-	return (tdb->map_ptr
-		&& (char *)p >= (char *)tdb->map_ptr
-		&& (char *)p < (char *)tdb->map_ptr + tdb->map_size);
+	struct tdb_access_hdr **hp;
+
+	for (hp = &tdb->access; *hp; hp = &(*hp)->next) {
+		if (*hp + 1 == p)
+			return hp;
+	}
+	return NULL;
 }
 
 void tdb_access_release(struct tdb_context *tdb, const void *p)
 {
-	if (is_direct(tdb, p))
+	struct tdb_access_hdr *hdr, **hp = find_hdr(tdb, p);
+
+	if (hp) {
+		hdr = *hp;
+		*hp = hdr->next;
+		free(hdr);
+	} else
 		tdb->direct_access--;
-	else
-		free((struct tdb_access_hdr *)p - 1);
 }
 
-int tdb_access_commit(struct tdb_context *tdb, void *p)
+enum TDB_ERROR tdb_access_commit(struct tdb_context *tdb, void *p)
 {
-	int ret = 0;
-
-	if (!tdb->map_ptr
-	    || (char *)p < (char *)tdb->map_ptr
-	    || (char *)p >= (char *)tdb->map_ptr + tdb->map_size) {
-		struct tdb_access_hdr *hdr;
+	struct tdb_access_hdr *hdr, **hp = find_hdr(tdb, p);
+	enum TDB_ERROR ecode;
 
-		hdr = (struct tdb_access_hdr *)p - 1;
+	if (hp) {
+		hdr = *hp;
 		if (hdr->convert)
-			ret = tdb_write_convert(tdb, hdr->off, p, hdr->len);
+			ecode = tdb_write_convert(tdb, hdr->off, p, hdr->len);
 		else
-			ret = tdb_write(tdb, hdr->off, p, hdr->len);
+			ecode = tdb_write(tdb, hdr->off, p, hdr->len);
+		*hp = hdr->next;
 		free(hdr);
-	} else
+	} else {
 		tdb->direct_access--;
+		ecode = TDB_SUCCESS;
+	}
 
-	return ret;
+	return ecode;
 }
 
-static void *tdb_direct(struct tdb_context *tdb, tdb_off_t off, size_t len)
+static void *tdb_direct(struct tdb_context *tdb, tdb_off_t off, size_t len,
+			bool write_mode)
 {
+	enum TDB_ERROR ecode;
+
 	if (unlikely(!tdb->map_ptr))
 		return NULL;
 
-	if (unlikely(tdb_oob(tdb, off + len, true) == -1))
-		return NULL;
+	ecode = tdb_oob(tdb, off + len, true);
+	if (unlikely(ecode != TDB_SUCCESS))
+		return TDB_ERR_PTR(ecode);
 	return (char *)tdb->map_ptr + off;
 }
 
-void add_stat_(struct tdb_context *tdb, uint64_t *stat, size_t val)
+void add_stat_(struct tdb_context *tdb, uint64_t *s, size_t val)
 {
-	if ((uintptr_t)stat < (uintptr_t)tdb->stats + tdb->stats->size)
-		*stat += val;
+	if ((uintptr_t)s < (uintptr_t)tdb->stats + tdb->stats->size)
+		*s += val;
 }
 
 static const struct tdb_methods io_methods = {