Date:	Thu, 17 Nov 2011 16:12:43 -0500
From:	Theodore Ts'o <tytso@....edu>
To:	Ext4 Developers List <linux-ext4@...r.kernel.org>
Cc:	Theodore Ts'o <tytso@....edu>
Subject: [PATCH 1/2] debugfs: add filefrag command

Add the ability to report on the fragmentation of a file on a file
system opened using debugfs.

Signed-off-by: "Theodore Ts'o" <tytso@....edu>
---
 debugfs/Makefile.in      |    8 +-
 debugfs/debug_cmds.ct    |    3 +
 debugfs/debugfs.8.in     |   21 +++
 debugfs/debugfs.h        |    1 +
 debugfs/filefrag.c       |  324 ++++++++++++++++++++++++++++++++++++++++++++++
 debugfs/ro_debug_cmds.ct |    3 +
 6 files changed, 357 insertions(+), 3 deletions(-)
 create mode 100644 debugfs/filefrag.c

diff --git a/debugfs/Makefile.in b/debugfs/Makefile.in
index e03a3c6..c6aaa3a 100644
--- a/debugfs/Makefile.in
+++ b/debugfs/Makefile.in
@@ -17,15 +17,17 @@ MANPAGES=	debugfs.8
 MK_CMDS=	_SS_DIR_OVERRIDE=../lib/ss ../lib/ss/mk_cmds
 
 DEBUG_OBJS= debug_cmds.o debugfs.o util.o ncheck.o icheck.o ls.o \
-	lsdel.o dump.o set_fields.o logdump.o htree.o unused.o e2freefrag.o
+	lsdel.o dump.o set_fields.o logdump.o htree.o unused.o e2freefrag.o \
+	filefrag.o
 
 RO_DEBUG_OBJS= ro_debug_cmds.o ro_debugfs.o util.o ncheck.o icheck.o ls.o \
-	lsdel.o logdump.o htree.o e2freefrag.o
+	lsdel.o logdump.o htree.o e2freefrag.o filefrag.o
 
 SRCS= debug_cmds.c $(srcdir)/debugfs.c $(srcdir)/util.c $(srcdir)/ls.c \
 	$(srcdir)/ncheck.c $(srcdir)/icheck.c $(srcdir)/lsdel.c \
 	$(srcdir)/dump.c $(srcdir)/set_fields.c ${srcdir}/logdump.c \
-	$(srcdir)/htree.c $(srcdir)/unused.c
+	$(srcdir)/htree.c $(srcdir)/unused.c ${srcdir}/../misc/e2freefrag.c \
+	$(srcdir)/filefrag.c
 
 LIBS= $(LIBEXT2FS) $(LIBE2P) $(LIBSS) $(LIBCOM_ERR) $(LIBBLKID) \
 	$(LIBUUID)
diff --git a/debugfs/debug_cmds.ct b/debugfs/debug_cmds.ct
index 47de672..af969b1 100644
--- a/debugfs/debug_cmds.ct
+++ b/debugfs/debug_cmds.ct
@@ -52,6 +52,9 @@ request do_dump_extents, "Dump extents information ",
 request do_blocks, "Dump blocks used by an inode ",
 	blocks;
 
+request do_filefrag, "Report fragmentation information for an inode",
+	filefrag;
+
 request do_link, "Create directory link",
 	link, ln;
 
diff --git a/debugfs/debugfs.8.in b/debugfs/debugfs.8.in
index 69490ff..70c8326 100644
--- a/debugfs/debugfs.8.in
+++ b/debugfs/debugfs.8.in
@@ -251,6 +251,27 @@ Set or clear various filesystem features in the superblock.  After setting
 or clearing any filesystem features that were requested, print the current
 state of the filesystem feature set.
 .TP
+.I filefrag [-dvr] filespec
+Print the number of contiguous extents in
+.IR filespec .
+If
+.I filespec
+is a directory and the
+.I -d
+option is not specified,
+.I filefrag
+will print the number of contiguous extents for each file in
+the directory.  The
+.I -v
+option will cause
+.I filefrag
+print a tabular listing of the contiguous extents in the
+file.  The
+.I -r
+option will cause
+.I filefrag
+to do a recursive listing of the directory.
+.TP
 .I find_free_block [count [goal]]
 Find the first 
 .I count
diff --git a/debugfs/debugfs.h b/debugfs/debugfs.h
index 6d7dfcd..0afa1df 100644
--- a/debugfs/debugfs.h
+++ b/debugfs/debugfs.h
@@ -134,3 +134,4 @@ extern void do_supported_features(int argc, char **argv);
 extern void do_punch(int argc, char **argv);
 
 extern void do_freefrag(int argc, char **argv);
+extern void do_filefrag(int argc, char *argv[]);
diff --git a/debugfs/filefrag.c b/debugfs/filefrag.c
new file mode 100644
index 0000000..30933b6
--- /dev/null
+++ b/debugfs/filefrag.c
@@ -0,0 +1,324 @@
+/*
+ * filefrag.c --- display the fragmentation information for a file
+ *
+ * Copyright (C) 2011 Theodore Ts'o.  This file may be redistributed
+ * under the terms of the GNU Public License.
+ */
+
+#include "config.h"
+#include <stdio.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <ctype.h>
+#include <string.h>
+#include <time.h>
+#ifdef HAVE_ERRNO_H
+#include <errno.h>
+#endif
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <utime.h>
+#ifdef HAVE_GETOPT_H
+#include <getopt.h>
+#else
+extern int optind;
+extern char *optarg;
+#endif
+
+#include "debugfs.h"
+
+#define VERBOSE_OPT	0x0001
+#define DIR_OPT		0x0002
+#define RECURSIVE_OPT	0x0004
+
+struct dir_list {
+	char		*name;
+	ext2_ino_t	ino;
+	struct dir_list	*next;
+};
+
+struct filefrag_struct {
+	FILE		*f;
+	const char	*name;
+	const char	*dir_name;
+	int		options;
+	int		logical_width;
+	int		physical_width;
+	int		ext;
+	int		cont_ext;
+	e2_blkcnt_t	num;
+	e2_blkcnt_t	logical_start;
+	blk64_t		physical_start;
+	blk64_t		expected;
+	struct dir_list *dir_list, *dir_last;
+};
+
+static int int_log10(unsigned long long arg)
+{
+	int     l = 0;
+
+	arg = arg / 10;
+	while (arg) {
+		l++;
+		arg = arg / 10;
+	}
+	return l;
+}
+
+static void print_header(struct filefrag_struct *fs)
+{
+	if (fs->options & VERBOSE_OPT) {
+		fprintf(fs->f, "%4s %*s %*s %*s %*s\n", "ext",
+			fs->logical_width, "logical", fs->physical_width,
+			"physical", fs->physical_width, "expected",
+			fs->logical_width, "length");
+	}
+}
+
+static void report_filefrag(struct filefrag_struct *fs)
+{
+	if (fs->num == 0)
+		return;
+	if (fs->options & VERBOSE_OPT) {
+		if (fs->expected)
+			fprintf(fs->f, "%4d %*lu %*llu %*llu %*lu\n", fs->ext,
+				fs->logical_width,
+				(unsigned long) fs->logical_start,
+				fs->physical_width, fs->physical_start,
+				fs->physical_width, fs->expected,
+				fs->logical_width, (unsigned long) fs->num);
+		else
+			fprintf(fs->f, "%4d %*lu %*llu %*s %*lu\n", fs->ext,
+				fs->logical_width,
+				(unsigned long) fs->logical_start,
+				fs->physical_width, fs->physical_start,
+				fs->physical_width, "",
+				fs->logical_width, (unsigned long) fs->num);
+	}
+	fs->ext++;
+}
+
+static int filefrag_blocks_proc(ext2_filsys ext4_fs EXT2FS_ATTR((unused)),
+				blk64_t *blocknr, e2_blkcnt_t blockcnt,
+				blk64_t ref_block EXT2FS_ATTR((unused)),
+				int ref_offset EXT2FS_ATTR((unused)),
+				void *private)
+{
+	struct filefrag_struct *fs = private;
+
+	if (blockcnt < 0 || *blocknr == 0)
+		return 0;
+
+	if ((fs->num == 0) || (blockcnt != fs->logical_start + fs->num) ||
+	    (*blocknr != fs->physical_start + fs->num)) {
+		report_filefrag(fs);
+		if (blockcnt == fs->logical_start + fs->num)
+			fs->expected = fs->physical_start + fs->num;
+		else
+			fs->expected = 0;
+		fs->logical_start = blockcnt;
+		fs->physical_start = *blocknr;
+		fs->num = 1;
+		fs->cont_ext++;
+	} else
+		fs->num++;
+	return 0;
+}
+
+static void filefrag(ext2_ino_t ino, struct ext2_inode *inode,
+		     struct filefrag_struct *fs)
+{
+	errcode_t	retval;
+	int		blocksize = current_fs->blocksize;
+
+	fs->logical_width = int_log10((EXT2_I_SIZE(inode) + blocksize - 1) /
+				      blocksize) + 1;
+	if (fs->logical_width < 7)
+		fs->logical_width = 7;
+	fs->ext = 0;
+	fs->cont_ext = 0;
+	fs->logical_start = 0;
+	fs->physical_start = 0;
+	fs->num = 0;
+
+	if (fs->options & VERBOSE_OPT) {
+		blk64_t num_blocks = ext2fs_inode_i_blocks(current_fs, inode);
+
+		if (!(current_fs->super->s_feature_ro_compat &
+		     EXT4_FEATURE_RO_COMPAT_HUGE_FILE) ||
+		    !(inode->i_flags & EXT4_HUGE_FILE_FL))
+			num_blocks /= current_fs->blocksize / 512;
+
+		fprintf(fs->f, "\n%s has %llu block(s), i_size is %llu\n",
+			fs->name, num_blocks, EXT2_I_SIZE(inode));
+	}
+	print_header(fs);
+	retval = ext2fs_block_iterate3(current_fs, ino,
+				       BLOCK_FLAG_READ_ONLY, NULL,
+				       filefrag_blocks_proc, fs);
+	if (retval)
+		com_err("ext2fs_block_iterate3", retval, 0);
+
+	report_filefrag(fs);
+	fprintf(fs->f, "%s: %d contiguous extents%s\n", fs->name, fs->ext,
+		LINUX_S_ISDIR(inode->i_mode) ? " (dir)" : "");
+}
+
+static int filefrag_dir_proc(ext2_ino_t dir EXT2FS_ATTR((unused)),
+			     int	entry,
+			     struct ext2_dir_entry *dirent,
+			     int	offset EXT2FS_ATTR((unused)),
+			     int	blocksize EXT2FS_ATTR((unused)),
+			     char	*buf EXT2FS_ATTR((unused)),
+			     void	*private)
+{
+	struct filefrag_struct *fs = private;
+	struct ext2_inode	inode;
+	ext2_ino_t		ino;
+	char			name[EXT2_NAME_LEN + 1];
+	char			*cp;
+	int			thislen;
+
+	if (entry == DIRENT_DELETED_FILE)
+		return 0;
+
+	thislen = dirent->name_len & 0xFF;
+	strncpy(name, dirent->name, thislen);
+	name[thislen] = '\0';
+	ino = dirent->inode;
+
+	if (!strcmp(name, ".") || !strcmp(name, ".."))
+		return 0;
+
+	cp = malloc(strlen(fs->dir_name) + strlen(name) + 2);
+	if (!cp) {
+		fprintf(stderr, "Couldn't allocate memory for %s/%s\n",
+			fs->dir_name, name);
+		return 0;
+	}
+
+	sprintf(cp, "%s/%s", fs->dir_name, name);
+	fs->name = cp;
+
+	if (debugfs_read_inode(ino, &inode, fs->name))
+		goto errout;
+
+	filefrag(ino, &inode, fs);
+
+	if ((fs->options & RECURSIVE_OPT) && LINUX_S_ISDIR(inode.i_mode)) {
+		struct dir_list *p;
+
+		p = malloc(sizeof(struct dir_list));
+		if (!p) {
+			fprintf(stderr, "Couldn't allocate dir_list for %s\n",
+				fs->name);
+			goto errout;
+		}
+		memset(p, 0, sizeof(struct dir_list));
+		p->name = cp;
+		p->ino = ino;
+		if (fs->dir_last)
+			fs->dir_last->next = p;
+		else
+			fs->dir_list = p;
+		fs->dir_last = p;
+		return 0;
+	}
+errout:
+	free(cp);
+	fs->name = 0;
+	return 0;
+}
+
+
+static void dir_iterate(ext2_ino_t ino, struct filefrag_struct *fs)
+{
+	errcode_t	retval;
+	struct dir_list	*p = NULL;
+
+	fs->dir_name = fs->name;
+
+	while (1) {
+		retval = ext2fs_dir_iterate2(current_fs, ino, 0,
+					     0, filefrag_dir_proc, fs);
+		if (retval)
+			com_err("ext2fs_dir_iterate2", retval, 0);
+		if (p) {
+			free(p->name);
+			fs->dir_list = p->next;
+			if (!fs->dir_list)
+				fs->dir_last = 0;
+			free(p);
+		}
+		p = fs->dir_list;
+		if (!p)
+			break;
+		ino = p->ino;
+		fs->dir_name = p->name;
+	}
+}
+
+void do_filefrag(int argc, char *argv[])
+{
+	struct filefrag_struct fs;
+	struct ext2_inode inode;
+	ext2_ino_t	ino;
+	int		c;
+
+	memset(&fs, 0, sizeof(fs));
+	if (check_fs_open(argv[0]))
+		return;
+
+	reset_getopt();
+	while ((c = getopt (argc, argv, "dvr")) != EOF) {
+		switch (c) {
+		case 'd':
+			fs.options |= DIR_OPT;
+			break;
+		case 'v':
+			fs.options |= VERBOSE_OPT;
+			break;
+		case 'r':
+			fs.options |= RECURSIVE_OPT;
+			break;
+		default:
+			goto print_usage;
+		}
+	}
+
+	if (argc > optind+1) {
+	print_usage:
+		com_err(0, 0, "Usage: filefrag [-dv] file");
+		return;
+	}
+
+	if (argc == optind) {
+		ino = cwd;
+		fs.name = ".";
+	} else {
+		ino = string_to_inode(argv[optind]);
+		fs.name = argv[optind];
+	}
+	if (!ino)
+		return;
+
+	if (debugfs_read_inode(ino, &inode, argv[0]))
+		return;
+
+	fs.f = open_pager();
+	fs.physical_width = int_log10(ext2fs_blocks_count(current_fs->super));
+	fs.physical_width++;
+	if (fs.physical_width < 8)
+		fs.physical_width = 8;
+
+	if (!LINUX_S_ISDIR(inode.i_mode) || (fs.options & DIR_OPT))
+		filefrag(ino, &inode, &fs);
+	else
+		dir_iterate(ino, &fs);
+
+	fprintf(fs.f, "\n");
+	close_pager(fs.f);
+
+	return;
+}
diff --git a/debugfs/ro_debug_cmds.ct b/debugfs/ro_debug_cmds.ct
index 7eb552d..4feb621 100644
--- a/debugfs/ro_debug_cmds.ct
+++ b/debugfs/ro_debug_cmds.ct
@@ -45,6 +45,9 @@ request do_dump_extents, "Dump extents information ",
 request do_blocks, "Dump blocks used by an inode ",
 	blocks;
 
+request do_filefrag, "Report fragmentation information for an inode",
+	filefrag;
+
 request do_testi, "Test an inode's in-use flag",
 	testi;
 
-- 
1.7.4.1.22.gec8e1.dirty

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