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Message-ID: <149088948402.25895.8126454500151691913.stgit@birch.djwong.org>
Date: Thu, 30 Mar 2017 08:58:04 -0700
From: "Darrick J. Wong" <darrick.wong@...cle.com>
To: darrick.wong@...cle.com
Cc: linux-xfs@...r.kernel.org, linux-fsdevel@...r.kernel.org,
linux-ext4@...r.kernel.org, linux-api@...r.kernel.org
Subject: [PATCH 1/9] vfs: add common GETFSMAP ioctl definitions
From: Darrick J. Wong <darrick.wong@...cle.com>
Add the GETFSMAP headers to the VFS kernel headers
Signed-off-by: Darrick J. Wong <darrick.wong@...cle.com>
---
include/uapi/linux/fsmap.h | 112 ++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 112 insertions(+)
create mode 100644 include/uapi/linux/fsmap.h
diff --git a/include/uapi/linux/fsmap.h b/include/uapi/linux/fsmap.h
new file mode 100644
index 0000000..7e8e5f0b
--- /dev/null
+++ b/include/uapi/linux/fsmap.h
@@ -0,0 +1,112 @@
+/*
+ * FS_IOC_GETFSMAP ioctl infrastructure.
+ *
+ * Copyright (C) 2017 Oracle. All Rights Reserved.
+ *
+ * Author: Darrick J. Wong <darrick.wong@...cle.com>
+ */
+#ifndef _LINUX_FSMAP_H
+#define _LINUX_FSMAP_H
+
+#include <linux/types.h>
+
+/*
+ * Structure for FS_IOC_GETFSMAP.
+ *
+ * The memory layout for this call are the scalar values defined in
+ * struct fsmap_head, followed by two struct fsmap that describe
+ * the lower and upper bound of mappings to return, followed by an
+ * array of struct fsmap mappings.
+ *
+ * fmh_iflags control the output of the call, whereas fmh_oflags report
+ * on the overall record output. fmh_count should be set to the
+ * length of the fmh_recs array, and fmh_entries will be set to the
+ * number of entries filled out during each call. If fmh_count is
+ * zero, the number of reverse mappings will be returned in
+ * fmh_entries, though no mappings will be returned. fmh_reserved
+ * must be set to zero.
+ *
+ * The two elements in the fmh_keys array are used to constrain the
+ * output. The first element in the array should represent the
+ * lowest disk mapping ("low key") that the user wants to learn
+ * about. If this value is all zeroes, the filesystem will return
+ * the first entry it knows about. For a subsequent call, the
+ * contents of fsmap_head.fmh_recs[fsmap_head.fmh_count - 1] should be
+ * copied into fmh_keys[0] to have the kernel start where it left off.
+ *
+ * The second element in the fmh_keys array should represent the
+ * highest disk mapping ("high key") that the user wants to learn
+ * about. If this value is all ones, the filesystem will not stop
+ * until it runs out of mapping to return or runs out of space in
+ * fmh_recs.
+ *
+ * fmr_device can be either a 32-bit cookie representing a device, or
+ * a 32-bit dev_t if the FMH_OF_DEV_T flag is set. fmr_physical,
+ * fmr_offset, and fmr_length are expressed in units of bytes.
+ * fmr_owner is either an inode number, or a special value if
+ * FMR_OF_SPECIAL_OWNER is set in fmr_flags.
+ */
+struct fsmap {
+ __u32 fmr_device; /* device id */
+ __u32 fmr_flags; /* mapping flags */
+ __u64 fmr_physical; /* device offset of segment */
+ __u64 fmr_owner; /* owner id */
+ __u64 fmr_offset; /* file offset of segment */
+ __u64 fmr_length; /* length of segment */
+ __u64 fmr_reserved[3]; /* must be zero */
+};
+
+struct fsmap_head {
+ __u32 fmh_iflags; /* control flags */
+ __u32 fmh_oflags; /* output flags */
+ __u32 fmh_count; /* # of entries in array incl. input */
+ __u32 fmh_entries; /* # of entries filled in (output). */
+ __u64 fmh_reserved[6]; /* must be zero */
+
+ struct fsmap fmh_keys[2]; /* low and high keys for the mapping search */
+ struct fsmap fmh_recs[]; /* returned records */
+};
+
+/* Size of an fsmap_head with room for nr records. */
+static inline size_t
+fsmap_sizeof(
+ unsigned int nr)
+{
+ return sizeof(struct fsmap_head) + nr * sizeof(struct fsmap);
+}
+
+/* Start the next fsmap query at the end of the current query results. */
+static inline void
+fsmap_advance(
+ struct fsmap_head *head)
+{
+ head->fmh_keys[0] = head->fmh_recs[head->fmh_entries - 1];
+}
+
+/* fmh_iflags values - set by FS_IOC_GETFSMAP caller in the header. */
+/* no flags defined yet */
+#define FMH_IF_VALID 0
+
+/* fmh_oflags values - returned in the header segment only. */
+#define FMH_OF_DEV_T 0x1 /* fmr_device values will be dev_t */
+
+/* fmr_flags values - returned for each non-header segment */
+#define FMR_OF_PREALLOC 0x1 /* segment = unwritten pre-allocation */
+#define FMR_OF_ATTR_FORK 0x2 /* segment = attribute fork */
+#define FMR_OF_EXTENT_MAP 0x4 /* segment = extent map */
+#define FMR_OF_SHARED 0x8 /* segment = shared with another file */
+#define FMR_OF_SPECIAL_OWNER 0x10 /* owner is a special value */
+#define FMR_OF_LAST 0x20 /* segment is the last in the FS */
+
+/* Each FS gets to define its own special owner codes. */
+#define FMR_OWNER(type, code) (((__u64)type << 32) | \
+ ((__u64)code & 0xFFFFFFFFULL))
+#define FMR_OWNER_TYPE(owner) ((__u32)((__u64)owner >> 32))
+#define FMR_OWNER_CODE(owner) ((__u32)(((__u64)owner & 0xFFFFFFFFULL)))
+#define FMR_OWN_FREE FMR_OWNER(0, 1) /* free space */
+#define FMR_OWN_UNKNOWN FMR_OWNER(0, 2) /* unknown owner */
+#define FMR_OWN_METADATA FMR_OWNER(0, 3) /* metadata */
+
+#define FS_IOC_GETFSMAP _IOWR('X', 59, struct fsmap_head)
+
+#endif /* _LINUX_FSMAP_H */
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