[PATCH V2] e2fsprogs: support EXT2_FLAG_BG_TRIMMED and EXT2_FLAGS_TRACK_TRIM

[Li Dongyang <dongyangli@ddn.com>]

This adds EXT2_FLAG_BG_TRIMMED, which is set on block group
descriptors during mke2fs after discard is done for that group.
The EXT2_FLAG_BG_TRIMMED flag is cleared on the block group when
we free blocks.

Introduce EXT2_FLAGS_TRACK_TRIM, which is a new super block flag,
to indicate whether we should honour the EXT2_FLAG_BG_TRIMMED
set on each block group.
EXT2_FLAGS_TRACK_TRIM itself can be turned on/off via tune2fs.

Make dumpe2fs aware of the new flags.

Cc: Shuichi Ihara <sihara@ddn.com>
Cc: Andreas Dilger <adilger@dilger.ca>
Cc: Wang Shilong <wangshilong1991@gmail.com>
Signed-off-by: Wang Shilong <wshilong@ddn.com>
Signed-off-by: Li Dongyang <dongyangli@ddn.com>
---
v1->v2:
set BG_TRIMMED flag on gd progressively as we discard the groups.
---
 lib/e2p/ls.c             |  4 ++++
 lib/ext2fs/alloc_stats.c |  8 ++++++--
 lib/ext2fs/ext2_fs.h     |  2 ++
 misc/dumpe2fs.c          |  2 ++
 misc/mke2fs.c            | 34 +++++++++++++++++-----------------
 misc/tune2fs.8.in        |  8 ++++++++
 misc/tune2fs.c           | 10 ++++++++++
 7 files changed, 49 insertions(+), 19 deletions(-)

diff --git a/lib/e2p/ls.c b/lib/e2p/ls.c
index 0b74aea2b..4b356eca6 100644
--- a/lib/e2p/ls.c
+++ b/lib/e2p/ls.c
@@ -162,6 +162,10 @@ static void print_super_flags(struct ext2_super_block * s, FILE *f)
 		fputs("test_filesystem ", f);
 		flags_found++;
 	}
+	if (s->s_flags & EXT2_FLAGS_TRACK_TRIM) {
+		fputs("track_trim ", f);
+		flags_found++;
+	}
 	if (flags_found)
 		fputs("\n", f);
 	else
diff --git a/lib/ext2fs/alloc_stats.c b/lib/ext2fs/alloc_stats.c
index 6f98bcc7c..4e03f92a4 100644
--- a/lib/ext2fs/alloc_stats.c
+++ b/lib/ext2fs/alloc_stats.c
@@ -70,10 +70,12 @@ void ext2fs_block_alloc_stats2(ext2_filsys fs, blk64_t blk, int inuse)
 #endif
 		return;
 	}
-	if (inuse > 0)
+	if (inuse > 0) {
 		ext2fs_mark_block_bitmap2(fs->block_map, blk);
-	else
+	} else {
 		ext2fs_unmark_block_bitmap2(fs->block_map, blk);
+		ext2fs_bg_flags_clear(fs, group, EXT2_BG_TRIMMED);
+	}
 	ext2fs_bg_free_blocks_count_set(fs, group, ext2fs_bg_free_blocks_count(fs, group) - inuse);
 	ext2fs_bg_flags_clear(fs, group, EXT2_BG_BLOCK_UNINIT);
 	ext2fs_group_desc_csum_set(fs, group);
@@ -139,6 +141,8 @@ void ext2fs_block_alloc_stats_range(ext2_filsys fs, blk64_t blk,
 			ext2fs_bg_free_blocks_count(fs, group) -
 			inuse*n/EXT2FS_CLUSTER_RATIO(fs));
 		ext2fs_bg_flags_clear(fs, group, EXT2_BG_BLOCK_UNINIT);
+		if (inuse < 0)
+			ext2fs_bg_flags_clear(fs, group, EXT2_BG_TRIMMED);
 		ext2fs_group_desc_csum_set(fs, group);
 		ext2fs_free_blocks_count_add(fs->super, -inuse * (blk64_t) n);
 		blk += n;
diff --git a/lib/ext2fs/ext2_fs.h b/lib/ext2fs/ext2_fs.h
index 0fc9c09a5..88e1114c9 100644
--- a/lib/ext2fs/ext2_fs.h
+++ b/lib/ext2fs/ext2_fs.h
@@ -223,6 +223,7 @@ struct ext4_group_desc
 #define EXT2_BG_INODE_UNINIT	0x0001 /* Inode table/bitmap not initialized */
 #define EXT2_BG_BLOCK_UNINIT	0x0002 /* Block bitmap not initialized */
 #define EXT2_BG_INODE_ZEROED	0x0004 /* On-disk itable initialized to zero */
+#define EXT2_BG_TRIMMED		0x0008 /* Block group was trimmed */
 
 /*
  * Data structures used by the directory indexing feature
@@ -563,6 +564,7 @@ struct ext2_inode *EXT2_INODE(struct ext2_inode_large *large_inode)
 #define EXT2_FLAGS_SIGNED_HASH		0x0001  /* Signed dirhash in use */
 #define EXT2_FLAGS_UNSIGNED_HASH	0x0002  /* Unsigned dirhash in use */
 #define EXT2_FLAGS_TEST_FILESYS		0x0004	/* OK for use on development code */
+#define EXT2_FLAGS_TRACK_TRIM		0x0008	/* Track trim status in each bg */
 #define EXT2_FLAGS_IS_SNAPSHOT		0x0010	/* This is a snapshot image */
 #define EXT2_FLAGS_FIX_SNAPSHOT		0x0020	/* Snapshot inodes corrupted */
 #define EXT2_FLAGS_FIX_EXCLUDE		0x0040	/* Exclude bitmaps corrupted */
diff --git a/misc/dumpe2fs.c b/misc/dumpe2fs.c
index 7c080ed9f..afe569dff 100644
--- a/misc/dumpe2fs.c
+++ b/misc/dumpe2fs.c
@@ -131,6 +131,8 @@ static void print_bg_opts(ext2_filsys fs, dgrp_t i)
  		     &first);
 	print_bg_opt(bg_flags, EXT2_BG_INODE_ZEROED, "ITABLE_ZEROED",
  		     &first);
+	print_bg_opt(bg_flags, EXT2_BG_TRIMMED, "TRIMMED",
+		     &first);
 	if (!first)
 		fputc(']', stdout);
 	fputc('\n', stdout);
diff --git a/misc/mke2fs.c b/misc/mke2fs.c
index 4a9c1b092..0eff41aad 100644
--- a/misc/mke2fs.c
+++ b/misc/mke2fs.c
@@ -71,8 +71,6 @@ extern int optind;
 #define ZAP_BOOTBLOCK
 #endif
 
-#define DISCARD_STEP_MB		(2048)
-
 extern int isatty(int);
 extern FILE *fpopen(const char *cmd, const char *mode);
 
@@ -2872,9 +2870,7 @@ err:
 static int mke2fs_discard_device(ext2_filsys fs)
 {
 	struct ext2fs_numeric_progress_struct progress;
-	blk64_t blocks = ext2fs_blocks_count(fs->super);
-	blk64_t count = DISCARD_STEP_MB;
-	blk64_t cur = 0;
+	dgrp_t group;
 	int retval = 0;
 
 	/*
@@ -2886,22 +2882,26 @@ static int mke2fs_discard_device(ext2_filsys fs)
 	if (retval)
 		return retval;
 
-	count *= (1024 * 1024);
-	count /= fs->blocksize;
-
 	ext2fs_numeric_progress_init(fs, &progress,
 				     _("Discarding device blocks: "),
-				     blocks);
-	while (cur < blocks) {
-		ext2fs_numeric_progress_update(fs, &progress, cur);
+				     ext2fs_blocks_count(fs->super));
 
-		if (cur + count > blocks)
-			count = blocks - cur;
+	for (group = 0; group < fs->group_desc_count; group++) {
+		blk64_t start = ext2fs_group_first_block2(fs, group);
+		blk64_t count = ext2fs_group_blocks_count(fs, group);
+		int retval_discard;
 
-		retval = io_channel_discard(fs->io, cur, count);
-		if (retval)
-			break;
-		cur += count;
+		retval_discard = io_channel_discard(fs->io, start, count);
+		if (!retval_discard) {
+			ext2fs_bg_flags_set(fs, group, EXT2_BG_TRIMMED);
+			ext2fs_group_desc_csum_set(fs, group);
+			fs->super->s_flags |= EXT2_FLAGS_TRACK_TRIM;
+		} else if (!retval) {
+			retval = retval_discard;
+		}
+
+		ext2fs_numeric_progress_update(fs, &progress,
+					ext2fs_group_last_block2(fs, group));
 	}
 
 	if (retval) {
diff --git a/misc/tune2fs.8.in b/misc/tune2fs.8.in
index dcf108c1f..2eb7e88ed 100644
--- a/misc/tune2fs.8.in
+++ b/misc/tune2fs.8.in
@@ -273,6 +273,14 @@ mounted using experimental kernel code, such as the ext4dev file system.
 .B ^test_fs
 Clear the test_fs flag, indicating the file system should only be mounted
 using production-level file system code.
+.TP
+.B track_trim
+Set a flag in the file system superblock to make fstrim save the trim status
+in each block group and skip the block groups already been trimmed.
+.TP
+.B ^track_trim
+Clear the track_trim flag to make fstrim ignore the trim status saved in
+each block group, and trim every block group.
 .RE
 .TP
 .B \-f
diff --git a/misc/tune2fs.c b/misc/tune2fs.c
index 458f7cf6a..dd9e8eab0 100644
--- a/misc/tune2fs.c
+++ b/misc/tune2fs.c
@@ -2312,6 +2312,14 @@ static int parse_extended_opts(ext2_filsys fs, const char *opts)
 			sb->s_flags &= ~EXT2_FLAGS_TEST_FILESYS;
 			printf("Clearing test filesystem flag\n");
 			ext2fs_mark_super_dirty(fs);
+		} else if (!strcmp(token, "track_trim")) {
+			sb->s_flags |= EXT2_FLAGS_TRACK_TRIM;
+			printf("Setting track_trim flag\n");
+			ext2fs_mark_super_dirty(fs);
+		} else if (!strcmp(token, "^track_trim")) {
+			sb->s_flags &= ~EXT2_FLAGS_TRACK_TRIM;
+			printf("Clearing track_trim flag\n");
+			ext2fs_mark_super_dirty(fs);
 		} else if (strcmp(token, "stride") == 0) {
 			if (!arg) {
 				r_usage++;
@@ -2458,6 +2466,8 @@ static int parse_extended_opts(ext2_filsys fs, const char *opts)
 			"\tforce_fsck\n"
 			"\ttest_fs\n"
 			"\t^test_fs\n"
+			"\ttrack_trim\n"
+			"\t^track_trim\n"
 			"\tencoding=<encoding>\n"
 			"\tencoding_flags=<flags>\n"));
 		free(buf);
-- 
2.41.0