@@ -27,6 +27,7 @@ HFILES = \
libxfs_priv.h \
linux-err.h \
topology.h \
+ xfblob.h \
xfbtree.h \
xfile.h \
xfs_ag_resv.h \
@@ -71,6 +72,7 @@ CFILES = cache.c \
topology.c \
trans.c \
util.c \
+ xfblob.c \
xfbtree.c \
xfile.c \
xfs_ag.c \
new file mode 100644
@@ -0,0 +1,148 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2022 Oracle. All Rights Reserved.
+ * Author: Darrick J. Wong <djwong@kernel.org>
+ */
+#include "libxfs_priv.h"
+#include "libxfs.h"
+#include "libxfs/xfile.h"
+#include "libxfs/xfblob.h"
+
+/*
+ * XFS Blob Storage
+ * ================
+ * Stores and retrieves blobs using an xfile. Objects are appended to the file
+ * and the offset is returned as a magic cookie for retrieval.
+ */
+
+#define XB_KEY_MAGIC 0xABAADDAD
+struct xb_key {
+ uint32_t xb_magic; /* XB_KEY_MAGIC */
+ uint32_t xb_size; /* size of the blob, in bytes */
+ loff_t xb_offset; /* byte offset of this key */
+ /* blob comes after here */
+} __packed;
+
+/* Initialize a blob storage object. */
+int
+xfblob_create(
+ struct xfs_mount *mp,
+ const char *description,
+ struct xfblob **blobp)
+{
+ struct xfblob *blob;
+ struct xfile *xfile;
+ int error;
+
+ error = xfile_create(mp, 0, description, &xfile);
+ if (error)
+ return error;
+
+ blob = malloc(sizeof(struct xfblob));
+ if (!blob) {
+ error = -ENOMEM;
+ goto out_xfile;
+ }
+
+ blob->xfile = xfile;
+ blob->last_offset = PAGE_SIZE;
+
+ *blobp = blob;
+ return 0;
+
+out_xfile:
+ xfile_destroy(xfile);
+ return error;
+}
+
+/* Destroy a blob storage object. */
+void
+xfblob_destroy(
+ struct xfblob *blob)
+{
+ xfile_destroy(blob->xfile);
+ kfree(blob);
+}
+
+/* Retrieve a blob. */
+int
+xfblob_load(
+ struct xfblob *blob,
+ xfblob_cookie cookie,
+ void *ptr,
+ uint32_t size)
+{
+ struct xb_key key;
+ int error;
+
+ error = xfile_obj_load(blob->xfile, &key, sizeof(key), cookie);
+ if (error)
+ return error;
+
+ if (key.xb_magic != XB_KEY_MAGIC || key.xb_offset != cookie) {
+ ASSERT(0);
+ return -ENODATA;
+ }
+ if (size < key.xb_size) {
+ ASSERT(0);
+ return -EFBIG;
+ }
+
+ return xfile_obj_load(blob->xfile, ptr, key.xb_size,
+ cookie + sizeof(key));
+}
+
+/* Store a blob. */
+int
+xfblob_store(
+ struct xfblob *blob,
+ xfblob_cookie *cookie,
+ const void *ptr,
+ uint32_t size)
+{
+ struct xb_key key = {
+ .xb_offset = blob->last_offset,
+ .xb_magic = XB_KEY_MAGIC,
+ .xb_size = size,
+ };
+ loff_t pos = blob->last_offset;
+ int error;
+
+ error = xfile_obj_store(blob->xfile, &key, sizeof(key), pos);
+ if (error)
+ return error;
+
+ pos += sizeof(key);
+ error = xfile_obj_store(blob->xfile, ptr, size, pos);
+ if (error)
+ goto out_err;
+
+ *cookie = blob->last_offset;
+ blob->last_offset += sizeof(key) + size;
+ return 0;
+out_err:
+ xfile_discard(blob->xfile, blob->last_offset, sizeof(key));
+ return error;
+}
+
+/* Free a blob. */
+int
+xfblob_free(
+ struct xfblob *blob,
+ xfblob_cookie cookie)
+{
+ struct xb_key key;
+ int error;
+
+ error = xfile_obj_load(blob->xfile, &key, sizeof(key), cookie);
+ if (error)
+ return error;
+
+ if (key.xb_magic != XB_KEY_MAGIC || key.xb_offset != cookie) {
+ ASSERT(0);
+ return -ENODATA;
+ }
+
+ xfile_discard(blob->xfile, cookie, sizeof(key) + key.xb_size);
+ return 0;
+}
new file mode 100644
@@ -0,0 +1,25 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Copyright (C) 2022 Oracle. All Rights Reserved.
+ * Author: Darrick J. Wong <djwong@kernel.org>
+ */
+#ifndef __XFS_SCRUB_XFBLOB_H__
+#define __XFS_SCRUB_XFBLOB_H__
+
+struct xfblob {
+ struct xfile *xfile;
+ loff_t last_offset;
+};
+
+typedef loff_t xfblob_cookie;
+
+int xfblob_create(struct xfs_mount *mp, const char *descr,
+ struct xfblob **blobp);
+void xfblob_destroy(struct xfblob *blob);
+int xfblob_load(struct xfblob *blob, xfblob_cookie cookie, void *ptr,
+ uint32_t size);
+int xfblob_store(struct xfblob *blob, xfblob_cookie *cookie, const void *ptr,
+ uint32_t size);
+int xfblob_free(struct xfblob *blob, xfblob_cookie cookie);
+
+#endif /* __XFS_SCRUB_XFBLOB_H__ */
@@ -482,3 +482,14 @@ xfile_prealloc(
return -errno;
return 0;
}
+
+/* Discard pages backing a range of the xfile. */
+void
+xfile_discard(
+ struct xfile *xf,
+ loff_t pos,
+ unsigned long long count)
+{
+ fallocate(xf->fcb->fd, FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE,
+ pos, count);
+}
@@ -61,6 +61,7 @@ struct xfile_stat {
int xfile_stat(struct xfile *xf, struct xfile_stat *statbuf);
unsigned long long xfile_bytes(struct xfile *xf);
int xfile_dump(struct xfile *xf);
+void xfile_discard(struct xfile *xf, loff_t pos, unsigned long long count);
static inline loff_t xfile_size(struct xfile *xf)
{