Date:   Wed, 27 Jun 2018 18:57:31 +0300
From:   c17828 <artem.blagodarenko@...il.com>
To:     linux-ext4@...r.kernel.org
Cc:     adilger.kernel@...ger.ca, alexey.lyashkov@...il.com,
        Andreas Dilger <andreas.dilger@...el.com>,
        Artem Blagodarenko <artem.blagodarenko@...il.com>
Subject: [PATCH] filefrag: Lustre changes to filefrag FIEMAP handling

From: Andreas Dilger <andreas.dilger@...el.com>

Add support for multiple-device filesystems by defining a new
fe_device field in the fiemap_extent structure.  This allows
printing the filesystem-relative or linux block device number
associated with each extent of a file.  If a single filesystem
extent is mirrored to multiple block devices, the fe_device
field can be used to disambiguate the multiple copies.

If the "-l" (device-logical) option is given to filefrag, then
all extents for a particular device of a file are returned
before returning extents for the next device.  This makes it
easier to see if extent allocation within a single device is
contiguous, instead of returning all of the blocks of a file
interleaved in file-logical-offset order.

Change-Id: Icdefe4dbc319e6652c3d6641e1500f2cfaf63605
Signed-off-by: Andreas Dilger <andreas.dilger@...el.com>
Signed-off-by: Artem Blagodarenko <artem.blagodarenko@...il.com>
---
 lib/ext2fs/fiemap.h |  7 +++++-
 misc/filefrag.8.in  |  5 +++-
 misc/filefrag.c     | 67 +++++++++++++++++++++++++++++++++++++++++++----------
 3 files changed, 65 insertions(+), 14 deletions(-)

diff --git a/lib/ext2fs/fiemap.h b/lib/ext2fs/fiemap.h
index a331bc12..261a0b2b 100644
--- a/lib/ext2fs/fiemap.h
+++ b/lib/ext2fs/fiemap.h
@@ -19,7 +19,8 @@ struct fiemap_extent {
 	__u64 fe_length;   /* length in bytes for this extent */
 	__u64 fe_reserved64[2];
 	__u32 fe_flags;    /* FIEMAP_EXTENT_* flags for this extent */
-	__u32 fe_reserved[3];
+	__u32 fe_device;   /* device number (fs-specific if FIEMAP_EXTENT_NET)*/
+	__u32 fe_reserved[2];
 };
 
 struct fiemap {
@@ -42,6 +43,7 @@ struct fiemap {
 
 #define FIEMAP_FLAG_SYNC	0x00000001 /* sync file data before map */
 #define FIEMAP_FLAG_XATTR	0x00000002 /* map extended attribute tree */
+#define FIEMAP_FLAG_DEVICE_ORDER 0x40000000 /* return device ordered mapping */
 
 #define FIEMAP_FLAGS_COMPAT	(FIEMAP_FLAG_SYNC | FIEMAP_FLAG_XATTR)
 
@@ -67,4 +69,7 @@ struct fiemap {
 #define FIEMAP_EXTENT_SHARED		0x00002000 /* Space shared with other
 						    * files. */
 
+/* Network filesystem flags - use a high bit, don't conflict with upstream */
+#define FIEMAP_EXTENT_NET		0x80000000 /* Data stored remotely. */
+
 #endif /* _LINUX_FIEMAP_H */
diff --git a/misc/filefrag.8.in b/misc/filefrag.8.in
index 292b3b7d..fdba67f7 100644
--- a/misc/filefrag.8.in
+++ b/misc/filefrag.8.in
@@ -8,7 +8,7 @@ filefrag \- report on file fragmentation
 .BI \-b blocksize
 ]
 [
-.B \-BeksvxX
+.B \-BeklsvxX
 ]
 [
 .I files...
@@ -46,6 +46,9 @@ Print output in extent format, even for block-mapped files.
 .BI \-k
 Use 1024\-byte blocksize for output (identical to '\-b 1024').
 .TP
+.B \-l
+Extents are displayed in device-logical offset order.
+.TP
 .B \-s
 Sync the file before requesting the mapping.
 .TP
diff --git a/misc/filefrag.c b/misc/filefrag.c
index 9c57ab93..78e13076 100644
--- a/misc/filefrag.c
+++ b/misc/filefrag.c
@@ -54,14 +54,16 @@ int verbose = 0;
 int blocksize;		/* Use specified blocksize (default 1kB) */
 int sync_file = 0;	/* fsync file before getting the mapping */
 int xattr_map = 0;	/* get xattr mapping */
-int force_bmap;	/* force use of FIBMAP instead of FIEMAP */
+int force_bmap;		/* force use of FIBMAP instead of FIEMAP */
 int force_extent;	/* print output in extent format always */
+int device_offset;	/* extents report device-relative offsets */
 int logical_width = 8;
 int physical_width = 10;
 const char *ext_fmt = "%4d: %*llu..%*llu: %*llu..%*llu: %6llu: %s\n";
 const char *hex_fmt = "%4d: %*llx..%*llx: %*llx..%*llx: %6llx: %s\n";
 
-#define FILEFRAG_FIEMAP_FLAGS_COMPAT (FIEMAP_FLAG_SYNC | FIEMAP_FLAG_XATTR)
+#define FILEFRAG_FIEMAP_FLAGS_COMPAT (FIEMAP_FLAG_SYNC | FIEMAP_FLAG_XATTR |\
+				      FIEMAP_FLAG_DEVICE_ORDER)
 
 #define FIBMAP		_IO(0x00, 1)	/* bmap access */
 #define FIGETBSZ	_IO(0x00, 2)	/* get the block size used for bmap */
@@ -120,10 +122,10 @@ static void print_extent_header(void)
 {
 	printf(" ext: %*s %*s length: %*s flags:\n",
 	       logical_width * 2 + 3,
-	       "logical_offset:",
+	       device_offset ? "device_logical:" : "logical_offset:",
 	       physical_width * 2 + 3, "physical_offset:",
-	       physical_width + 1,
-	       "expected:");
+	       device_offset ? 5 : physical_width + 1,
+	       device_offset ? " dev:" : "expected:");
 }
 
 static void print_flag(__u32 *flags, __u32 mask, char *buf, const char *name)
@@ -159,11 +161,11 @@ static void print_extent_info(struct fiemap_extent *fm_extent, int cur_ex,
 		physical_blk = fm_extent->fe_physical >> blk_shift;
 	}
 
-	if (expected)
-		sprintf(flags, ext_fmt == hex_fmt ? "%*llx: " : "%*llu: ",
+	if (device_offset)
+		sprintf(flags, "%04x: ", fm_extent->fe_device);
+	else if (expected)
+		sprintf(flags, ext_fmt == hex_fmt ? "%*llx:" : "%*llu: ",
 			physical_width, expected >> blk_shift);
-	else
-		sprintf(flags, "%.*s  ", physical_width, "                   ");
 
 	fe_flags = fm_extent->fe_flags;
 	print_flag(&fe_flags, FIEMAP_EXTENT_LAST, flags, "last,");
@@ -177,6 +179,8 @@ static void print_extent_info(struct fiemap_extent *fm_extent, int cur_ex,
 	print_flag(&fe_flags, FIEMAP_EXTENT_UNWRITTEN, flags, "unwritten,");
 	print_flag(&fe_flags, FIEMAP_EXTENT_MERGED, flags, "merged,");
 	print_flag(&fe_flags, FIEMAP_EXTENT_SHARED, flags, "shared,");
+	print_flag(&fe_flags, FIEMAP_EXTENT_NET, flags, "net,");
+
 	/* print any unknown flags as hex values */
 	for (mask = 1; fe_flags != 0 && mask != 0; mask <<= 1) {
 		char hex[6];
@@ -217,6 +221,7 @@ static int filefrag_fiemap(int fd, int blk_shift, int *num_extents,
 	unsigned int i;
 	int fiemap_header_printed = 0;
 	int tot_extents = 0, n = 0;
+	int previous_device = 0;
 	int last = 0;
 	int rc;
 
@@ -228,6 +233,12 @@ static int filefrag_fiemap(int fd, int blk_shift, int *num_extents,
 	if (xattr_map)
 		flags |= FIEMAP_FLAG_XATTR;
 
+	if (device_offset) {
+		flags |= FIEMAP_FLAG_DEVICE_ORDER;
+		memset(fm_ext, 0, sizeof(struct fiemap_extent));
+	}
+
+retry_wo_device_order:
 	do {
 		fiemap->fm_length = ~0ULL;
 		fiemap->fm_flags = flags;
@@ -242,6 +253,10 @@ static int filefrag_fiemap(int fd, int blk_shift, int *num_extents,
 						"flags %x\n",
 				       fiemap->fm_flags);
 				fiemap_incompat_printed = 1;
+			} else if (rc == EBADR && (fiemap->fm_flags &
+						   FIEMAP_FLAG_DEVICE_ORDER)) {
+				flags &= ~FIEMAP_FLAG_DEVICE_ORDER;
+				goto retry_wo_device_order;
 			}
 			return rc;
 		}
@@ -260,6 +275,9 @@ static int filefrag_fiemap(int fd, int blk_shift, int *num_extents,
 					 fm_last.fe_length;
 			expected = fm_last.fe_physical +
 				   fm_ext[i].fe_logical - fm_last.fe_logical;
+			if (previous_device != fm_ext[i].fe_device)
+				previous_device = fm_ext[i].fe_device;
+
 			if (fm_ext[i].fe_logical != 0 &&
 			    fm_ext[i].fe_physical != expected &&
 			    fm_ext[i].fe_physical != expected_dense) {
@@ -278,8 +296,20 @@ static int filefrag_fiemap(int fd, int blk_shift, int *num_extents,
 			n++;
 		}
 
-		fiemap->fm_start = (fm_ext[i - 1].fe_logical +
-				    fm_ext[i - 1].fe_length);
+		/* For DEVICE_ORDER mappings, if EXTENT_LAST not yet found then
+		 * fm_start needs to be the same as it was for earlier ioctl.
+		 * The first extent is used to pass the end offset and device
+		 * of the last FIEMAP call.  Otherwise, we ask for extents
+		 * starting from where the last mapping ended. */
+		if (flags & FIEMAP_FLAG_DEVICE_ORDER) {
+			fm_ext[0].fe_logical =	fm_ext[i - 1].fe_logical +
+						fm_ext[i - 1].fe_length;
+			fm_ext[0].fe_device =	fm_ext[i - 1].fe_device;
+			fiemap->fm_start =	0;
+		} else {
+			fiemap->fm_start =	fm_ext[i - 1].fe_logical +
+						fm_ext[i - 1].fe_length;
+		}
 	} while (last == 0);
 
 	*num_extents = tot_extents;
@@ -303,6 +333,8 @@ static int filefrag_fibmap(int fd, int blk_shift, int *num_extents,
 	memset(&fm_ext, 0, sizeof(fm_ext));
 	memset(&fm_last, 0, sizeof(fm_last));
 	if (force_extent) {
+		memset(&fm_ext, 0, sizeof(fm_ext));
+		fm_ext.fe_device = st->st_dev;
 		fm_ext.fe_flags = FIEMAP_EXTENT_MERGED;
 	}
 
@@ -437,6 +469,13 @@ static int frag_report(const char *filename)
 			is_ext2 = 1;
 	}
 
+	/* Check if filesystem is Lustre.  Always print in extent format
+	 * with 1kB blocks, using the device-relative logical offsets. */
+	if (fsinfo.f_type == LUSTRE_SUPER_MAGIC) {
+		device_offset = 1;
+		blocksize = blocksize ?: 1024;
+	}
+
 	if (is_ext2) {
 		long cylgroups = div_ceil(fsinfo.f_blocks, blksize * 8);
 
@@ -524,10 +563,11 @@ int main(int argc, char**argv)
 	char **cpp;
 	int rc = 0, c;
 
-	while ((c = getopt(argc, argv, "Bb::eksvxX")) != EOF) {
+	while ((c = getopt(argc, argv, "Bb::eklsvxX")) != EOF) {
 		switch (c) {
 		case 'B':
 			force_bmap++;
+			force_extent = 0;
 			break;
 		case 'b':
 			if (optarg) {
@@ -567,6 +607,9 @@ int main(int argc, char**argv)
 		case 'k':
 			blocksize = 1024;
 			break;
+		case 'l':
+			device_offset++;
+			break;
 		case 's':
 			sync_file++;
 			break;
-- 
2.14.3

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