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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Damien Le Moal <damien.lemoal@wdc.com>,
        Chao Yu <yuchao0@huawei.com>, Jaegeuk Kim <jaegeuk@kernel.org>
Subject: [PATCH 4.19 004/276] f2fs: Fix use of number of devices
Date:   Wed, 29 May 2019 20:02:42 -0700
Message-Id: <20190530030523.689230340@linuxfoundation.org>
In-Reply-To: <20190530030523.133519668@linuxfoundation.org>
References: <20190530030523.133519668@linuxfoundation.org>
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From: Damien Le Moal <damien.lemoal@wdc.com>

commit 0916878da355650d7e77104a7ac0fa1784eca852 upstream.

For a single device mount using a zoned block device, the zone
information for the device is stored in the sbi->devs single entry
array and sbi->s_ndevs is set to 1. This differs from a single device
mount using a regular block device which does not allocate sbi->devs
and sets sbi->s_ndevs to 0.

However, sbi->s_devs == 0 condition is used throughout the code to
differentiate a single device mount from a multi-device mount where
sbi->s_ndevs is always larger than 1. This results in problems with
single zoned block device volumes as these are treated as multi-device
mounts but do not have the start_blk and end_blk information set. One
of the problem observed is skipping of zone discard issuing resulting in
write commands being issued to full zones or unaligned to a zone write
pointer.

Fix this problem by simply treating the cases sbi->s_ndevs == 0 (single
regular block device mount) and sbi->s_ndevs == 1 (single zoned block
device mount) in the same manner. This is done by introducing the
helper function f2fs_is_multi_device() and using this helper in place
of direct tests of sbi->s_ndevs value, improving code readability.

Fixes: 7bb3a371d199 ("f2fs: Fix zoned block device support")
Cc: <stable@vger.kernel.org>
Signed-off-by: Damien Le Moal <damien.lemoal@wdc.com>
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>


diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index 08314fb42652..4d02e76b648a 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -197,12 +197,14 @@ struct block_device *f2fs_target_device(struct f2fs_sb_info *sbi,
 	struct block_device *bdev = sbi->sb->s_bdev;
 	int i;
 
-	for (i = 0; i < sbi->s_ndevs; i++) {
-		if (FDEV(i).start_blk <= blk_addr &&
-					FDEV(i).end_blk >= blk_addr) {
-			blk_addr -= FDEV(i).start_blk;
-			bdev = FDEV(i).bdev;
-			break;
+	if (f2fs_is_multi_device(sbi)) {
+		for (i = 0; i < sbi->s_ndevs; i++) {
+			if (FDEV(i).start_blk <= blk_addr &&
+			    FDEV(i).end_blk >= blk_addr) {
+				blk_addr -= FDEV(i).start_blk;
+				bdev = FDEV(i).bdev;
+				break;
+			}
 		}
 	}
 	if (bio) {
@@ -216,6 +218,9 @@ int f2fs_target_device_index(struct f2fs_sb_info *sbi, block_t blkaddr)
 {
 	int i;
 
+	if (!f2fs_is_multi_device(sbi))
+		return 0;
+
 	for (i = 0; i < sbi->s_ndevs; i++)
 		if (FDEV(i).start_blk <= blkaddr && FDEV(i).end_blk >= blkaddr)
 			return i;
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index 1f5d5f62bb77..a4b6eacf22ea 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -1336,6 +1336,17 @@ static inline bool time_to_inject(struct f2fs_sb_info *sbi, int type)
 }
 #endif
 
+/*
+ * Test if the mounted volume is a multi-device volume.
+ *   - For a single regular disk volume, sbi->s_ndevs is 0.
+ *   - For a single zoned disk volume, sbi->s_ndevs is 1.
+ *   - For a multi-device volume, sbi->s_ndevs is always 2 or more.
+ */
+static inline bool f2fs_is_multi_device(struct f2fs_sb_info *sbi)
+{
+	return sbi->s_ndevs > 1;
+}
+
 /* For write statistics. Suppose sector size is 512 bytes,
  * and the return value is in kbytes. s is of struct f2fs_sb_info.
  */
@@ -3455,7 +3466,7 @@ static inline bool f2fs_force_buffered_io(struct inode *inode, int rw)
 {
 	return (f2fs_post_read_required(inode) ||
 			(rw == WRITE && test_opt(F2FS_I_SB(inode), LFS)) ||
-			F2FS_I_SB(inode)->s_ndevs);
+			f2fs_is_multi_device(F2FS_I_SB(inode)));
 }
 
 #ifdef CONFIG_F2FS_FAULT_INJECTION
diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index b3f46e3bec17..8d1eb8dec605 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -2539,7 +2539,7 @@ static int f2fs_ioc_flush_device(struct file *filp, unsigned long arg)
 							sizeof(range)))
 		return -EFAULT;
 
-	if (sbi->s_ndevs <= 1 || sbi->s_ndevs - 1 <= range.dev_num ||
+	if (!f2fs_is_multi_device(sbi) || sbi->s_ndevs - 1 <= range.dev_num ||
 			sbi->segs_per_sec != 1) {
 		f2fs_msg(sbi->sb, KERN_WARNING,
 			"Can't flush %u in %d for segs_per_sec %u != 1\n",
diff --git a/fs/f2fs/gc.c b/fs/f2fs/gc.c
index 5c8d00422237..d44b57a363ff 100644
--- a/fs/f2fs/gc.c
+++ b/fs/f2fs/gc.c
@@ -1256,7 +1256,7 @@ void f2fs_build_gc_manager(struct f2fs_sb_info *sbi)
 	sbi->gc_pin_file_threshold = DEF_GC_FAILED_PINNED_FILES;
 
 	/* give warm/cold data area from slower device */
-	if (sbi->s_ndevs && sbi->segs_per_sec == 1)
+	if (f2fs_is_multi_device(sbi) && sbi->segs_per_sec == 1)
 		SIT_I(sbi)->last_victim[ALLOC_NEXT] =
 				GET_SEGNO(sbi, FDEV(0).end_blk) + 1;
 }
diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index ac038563273d..03fa2c4d3d79 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -574,7 +574,7 @@ static int submit_flush_wait(struct f2fs_sb_info *sbi, nid_t ino)
 	int ret = 0;
 	int i;
 
-	if (!sbi->s_ndevs)
+	if (!f2fs_is_multi_device(sbi))
 		return __submit_flush_wait(sbi, sbi->sb->s_bdev);
 
 	for (i = 0; i < sbi->s_ndevs; i++) {
@@ -640,7 +640,8 @@ int f2fs_issue_flush(struct f2fs_sb_info *sbi, nid_t ino)
 		return ret;
 	}
 
-	if (atomic_inc_return(&fcc->issing_flush) == 1 || sbi->s_ndevs > 1) {
+	if (atomic_inc_return(&fcc->issing_flush) == 1 ||
+	    f2fs_is_multi_device(sbi)) {
 		ret = submit_flush_wait(sbi, ino);
 		atomic_dec(&fcc->issing_flush);
 
@@ -746,7 +747,7 @@ int f2fs_flush_device_cache(struct f2fs_sb_info *sbi)
 {
 	int ret = 0, i;
 
-	if (!sbi->s_ndevs)
+	if (!f2fs_is_multi_device(sbi))
 		return 0;
 
 	for (i = 1; i < sbi->s_ndevs; i++) {
@@ -1289,7 +1290,7 @@ static int __queue_discard_cmd(struct f2fs_sb_info *sbi,
 
 	trace_f2fs_queue_discard(bdev, blkstart, blklen);
 
-	if (sbi->s_ndevs) {
+	if (f2fs_is_multi_device(sbi)) {
 		int devi = f2fs_target_device_index(sbi, blkstart);
 
 		blkstart -= FDEV(devi).start_blk;
@@ -1638,7 +1639,7 @@ static int __f2fs_issue_discard_zone(struct f2fs_sb_info *sbi,
 	block_t lblkstart = blkstart;
 	int devi = 0;
 
-	if (sbi->s_ndevs) {
+	if (f2fs_is_multi_device(sbi)) {
 		devi = f2fs_target_device_index(sbi, blkstart);
 		blkstart -= FDEV(devi).start_blk;
 	}
@@ -2971,7 +2972,7 @@ static void update_device_state(struct f2fs_io_info *fio)
 	struct f2fs_sb_info *sbi = fio->sbi;
 	unsigned int devidx;
 
-	if (!sbi->s_ndevs)
+	if (!f2fs_is_multi_device(sbi))
 		return;
 
 	devidx = f2fs_target_device_index(sbi, fio->new_blkaddr);
-- 
2.21.0