[PATCH 1/3] f2fs: enhance the bit operation for SSR

[PATCH 1/3] f2fs: enhance the bit operation for SSR

[Jaegeuk Kim]

This patch enhances the existing bit operation when f2fs allocates SSR
blocks.

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
---
 fs/f2fs/segment.c | 50 ++++++++++++++++++++------------------------------
 1 file changed, 20 insertions(+), 30 deletions(-)

diff --git a/fs/f2fs/segment.c b/fs/f2fs/segment.c
index 74c4748..5fa519f 100644
--- a/fs/f2fs/segment.c
+++ b/fs/f2fs/segment.c
@@ -132,47 +132,37 @@ static unsigned long __find_rev_next_zero_bit(const unsigned long *addr,
 			unsigned long size, unsigned long offset)
 {
 	const unsigned long *p = addr + BIT_WORD(offset);
-	unsigned long result = offset & ~(BITS_PER_LONG - 1);
+	unsigned long result = size;
 	unsigned long tmp;
 
 	if (offset >= size)
 		return size;
 
-	size -= result;
+	size -= (offset & ~(BITS_PER_LONG - 1));
 	offset %= BITS_PER_LONG;
-	if (!offset)
-		goto aligned;
-
-	tmp = __reverse_ulong((unsigned char *)p);
-	tmp |= ~((~0UL << offset) >> offset);
-
-	if (size < BITS_PER_LONG)
-		goto found_first;
-	if (tmp != ~0UL)
-		goto found_middle;
-
-	size -= BITS_PER_LONG;
-	result += BITS_PER_LONG;
-	p++;
-aligned:
-	while (size & ~(BITS_PER_LONG - 1)) {
+
+	while (1) {
+		if (*p == ~0UL)
+			goto pass;
+
 		tmp = __reverse_ulong((unsigned char *)p);
+
+		if (offset)
+			tmp |= ~0UL << (BITS_PER_LONG - offset);
+		if (size < BITS_PER_LONG)
+			tmp |= ~0UL >> size;
 		if (tmp != ~0UL)
-			goto found_middle;
-		result += BITS_PER_LONG;
+			goto found;
+pass:
+		if (size <= BITS_PER_LONG)
+			break;
 		size -= BITS_PER_LONG;
+		offset = 0;
 		p++;
 	}
-	if (!size)
-		return result;
-
-	tmp = __reverse_ulong((unsigned char *)p);
-found_first:
-	tmp |= ~(~0UL << (BITS_PER_LONG - size));
-	if (tmp == ~0UL)	/* Are any bits zero? */
-		return result + size;   /* Nope. */
-found_middle:
-	return result + __reverse_ffz(tmp);
+	return result;
+found:
+	return result - size + __reverse_ffz(tmp);
 }
 
 void register_inmem_page(struct inode *inode, struct page *page)
-- 
2.4.9 (Apple Git-60)

[PATCH 2/3] f2fs: refactor f2fs_commit_super

[Jaegeuk Kim]

Previously, f2fs_commit_super hacks the bh->blocknr to write the broken
alternate superblock.
Instead of it, we should use the correct logic to retrieve its buffer head
with locking it appropriately.

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
---
 fs/f2fs/super.c | 32 ++++++++++++++++++++------------
 1 file changed, 20 insertions(+), 12 deletions(-)

diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index bd7e9c6..dbf16ad 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -1099,27 +1099,35 @@ out:
 int f2fs_commit_super(struct f2fs_sb_info *sbi, bool recover)
 {
 	struct buffer_head *sbh = sbi->raw_super_buf;
-	sector_t block = sbh->b_blocknr;
+	struct buffer_head *bh;
 	int err;
 
 	/* write back-up superblock first */
-	sbh->b_blocknr = block ? 0 : 1;
-	mark_buffer_dirty(sbh);
-	err = sync_dirty_buffer(sbh);
+	bh = sb_getblk(sbi->sb, sbh->b_blocknr ? 0 : 1);
+	if (!bh)
+		return -EIO;
 
-	sbh->b_blocknr = block;
+	lock_buffer(bh);
+	memcpy(bh->b_data, sbh->b_data, sbh->b_size);
+	WARN_ON(sbh->b_size != F2FS_BLKSIZE);
+	set_buffer_uptodate(bh);
+	set_buffer_dirty(bh);
+	unlock_buffer(bh);
+
+	/* it's rare case, we can do fua all the time */
+	err = __sync_dirty_buffer(bh, WRITE_FLUSH_FUA);
+	brelse(bh);
 
 	/* if we are in recovery path, skip writing valid superblock */
 	if (recover || err)
-		goto out;
+		return err;
 
 	/* write current valid superblock */
-	mark_buffer_dirty(sbh);
-	err = sync_dirty_buffer(sbh);
-out:
-	clear_buffer_write_io_error(sbh);
-	set_buffer_uptodate(sbh);
-	return err;
+	lock_buffer(sbh);
+	set_buffer_dirty(sbh);
+	unlock_buffer(sbh);
+
+	return __sync_dirty_buffer(sbh, WRITE_FLUSH_FUA);
 }
 
 static int f2fs_fill_super(struct super_block *sb, void *data, int silent)
-- 
2.4.9 (Apple Git-60)

[PATCH 2/3] f2fs: refactor f2fs_commit_super

[Jaegeuk Kim]

Previously, f2fs_commit_super hacks the bh->blocknr to write the broken
alternate superblock.
Instead of it, we should use the correct logic to retrieve its buffer head
with locking it appropriately.

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
---
 fs/f2fs/super.c | 32 ++++++++++++++++++++------------
 1 file changed, 20 insertions(+), 12 deletions(-)

diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index bd7e9c6..dbf16ad 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -1099,27 +1099,35 @@ out:
 int f2fs_commit_super(struct f2fs_sb_info *sbi, bool recover)
 {
 	struct buffer_head *sbh = sbi->raw_super_buf;
-	sector_t block = sbh->b_blocknr;
+	struct buffer_head *bh;
 	int err;
 
 	/* write back-up superblock first */
-	sbh->b_blocknr = block ? 0 : 1;
-	mark_buffer_dirty(sbh);
-	err = sync_dirty_buffer(sbh);
+	bh = sb_getblk(sbi->sb, sbh->b_blocknr ? 0 : 1);
+	if (!bh)
+		return -EIO;
 
-	sbh->b_blocknr = block;
+	lock_buffer(bh);
+	memcpy(bh->b_data, sbh->b_data, sbh->b_size);
+	WARN_ON(sbh->b_size != F2FS_BLKSIZE);
+	set_buffer_uptodate(bh);
+	set_buffer_dirty(bh);
+	unlock_buffer(bh);
+
+	/* it's rare case, we can do fua all the time */
+	err = __sync_dirty_buffer(bh, WRITE_FLUSH_FUA);
+	brelse(bh);
 
 	/* if we are in recovery path, skip writing valid superblock */
 	if (recover || err)
-		goto out;
+		return err;
 
 	/* write current valid superblock */
-	mark_buffer_dirty(sbh);
-	err = sync_dirty_buffer(sbh);
-out:
-	clear_buffer_write_io_error(sbh);
-	set_buffer_uptodate(sbh);
-	return err;
+	lock_buffer(sbh);
+	set_buffer_dirty(sbh);
+	unlock_buffer(sbh);
+
+	return __sync_dirty_buffer(sbh, WRITE_FLUSH_FUA);
 }
 
 static int f2fs_fill_super(struct super_block *sb, void *data, int silent)
-- 
2.4.9 (Apple Git-60)


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Use one codebase in this all-in-one HTML5 development environment.
Design, debug & build mobile apps & 2D/3D high-impact games for multiple OSs.
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RE: [f2fs-dev] [PATCH 2/3] f2fs: refactor f2fs_commit_super

[Chao Yu]

> -----Original Message-----
> From: Jaegeuk Kim [mailto:jaegeuk@kernel.org]
> Sent: Tuesday, December 08, 2015 6:53 AM
> To: linux-kernel@vger.kernel.org; linux-fsdevel@vger.kernel.org;
> linux-f2fs-devel@lists.sourceforge.net
> Cc: Jaegeuk Kim
> Subject: [f2fs-dev] [PATCH 2/3] f2fs: refactor f2fs_commit_super
> 
> Previously, f2fs_commit_super hacks the bh->blocknr to write the broken
> alternate superblock.
> Instead of it, we should use the correct logic to retrieve its buffer head
> with locking it appropriately.
> 
> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

Reviewed-by: Chao Yu <chao2.yu@samsung.com>

[PATCH 3/3] f2fs: use lock_buffer when changing superblock

[Jaegeuk Kim]

When modifying sb contents, we need to use lock its buffer.

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
---
 fs/f2fs/file.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index a018ed3..a16dfe9 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -1591,7 +1591,9 @@ static int f2fs_ioc_get_encryption_pwsalt(struct file *filp, unsigned long arg)
 		return err;
 
 	/* update superblock with uuid */
+	lock_buffer(sbi->raw_super_buf);
 	generate_random_uuid(sbi->raw_super->encrypt_pw_salt);
+	unlock_buffer(sbi->raw_super_buf);
 
 	err = f2fs_commit_super(sbi, false);
 
-- 
2.4.9 (Apple Git-60)

RE: [f2fs-dev] [PATCH 3/3] f2fs: use lock_buffer when changing superblock

[Chao Yu]

Hi Jaegeuk,

> -----Original Message-----
> From: Jaegeuk Kim [mailto:jaegeuk@kernel.org]
> Sent: Tuesday, December 08, 2015 6:53 AM
> To: linux-kernel@vger.kernel.org; linux-fsdevel@vger.kernel.org;
> linux-f2fs-devel@lists.sourceforge.net
> Cc: Jaegeuk Kim
> Subject: [f2fs-dev] [PATCH 3/3] f2fs: use lock_buffer when changing superblock
> 
> When modifying sb contents, we need to use lock its buffer.

How about applying the rule to _undo_ flow after f2fs_commit_super failed?

Thanks,

> 
> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
> ---
>  fs/f2fs/file.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
> index a018ed3..a16dfe9 100644
> --- a/fs/f2fs/file.c
> +++ b/fs/f2fs/file.c
> @@ -1591,7 +1591,9 @@ static int f2fs_ioc_get_encryption_pwsalt(struct file *filp, unsigned
> long arg)
>  		return err;
> 
>  	/* update superblock with uuid */
> +	lock_buffer(sbi->raw_super_buf);
>  	generate_random_uuid(sbi->raw_super->encrypt_pw_salt);
> +	unlock_buffer(sbi->raw_super_buf);
> 
>  	err = f2fs_commit_super(sbi, false);
> 
> --
> 2.4.9 (Apple Git-60)
> 
> 
> ------------------------------------------------------------------------------
> Go from Idea to Many App Stores Faster with Intel(R) XDK
> Give your users amazing mobile app experiences with Intel(R) XDK.
> Use one codebase in this all-in-one HTML5 development environment.
> Design, debug & build mobile apps & 2D/3D high-impact games for multiple OSs.
> http://pubads.g.doubleclick.net/gampad/clk?id=254741911&iu=/4140
> _______________________________________________
> Linux-f2fs-devel mailing list
> Linux-f2fs-devel@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel

Re: [f2fs-dev] [PATCH 3/3 v2] f2fs: use lock_buffer when changing superblock

[Jaegeuk Kim]

Agreed.

Change log from v1:
 o apply for _undo_ flow as well

>From ea212a4a7a432e0ecd0f0f53971b70172b3e7f96 Mon Sep 17 00:00:00 2001
From: Jaegeuk Kim <jaegeuk@kernel.org>
Date: Mon, 7 Dec 2015 10:18:54 -0800
Subject: [PATCH] f2fs: use lock_buffer when changing superblock

When modifying sb contents, we need to use lock its buffer.

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
---
 fs/f2fs/file.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index a018ed3..294e715 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -1591,14 +1591,18 @@ static int f2fs_ioc_get_encryption_pwsalt(struct file *filp, unsigned long arg)
 		return err;
 
 	/* update superblock with uuid */
+	lock_buffer(sbi->raw_super_buf);
 	generate_random_uuid(sbi->raw_super->encrypt_pw_salt);
+	unlock_buffer(sbi->raw_super_buf);
 
 	err = f2fs_commit_super(sbi, false);
 
 	mnt_drop_write_file(filp);
 	if (err) {
 		/* undo new data */
+		lock_buffer(sbi->raw_super_buf);
 		memset(sbi->raw_super->encrypt_pw_salt, 0, 16);
+		unlock_buffer(sbi->raw_super_buf);
 		return err;
 	}
 got_it:
-- 
2.4.9 (Apple Git-60)

Re: [PATCH 3/3 v2] f2fs: use lock_buffer when changing superblock

[Jaegeuk Kim]

Agreed.

Change log from v1:
 o apply for _undo_ flow as well

>From ea212a4a7a432e0ecd0f0f53971b70172b3e7f96 Mon Sep 17 00:00:00 2001
From: Jaegeuk Kim <jaegeuk@kernel.org>
Date: Mon, 7 Dec 2015 10:18:54 -0800
Subject: [PATCH] f2fs: use lock_buffer when changing superblock

When modifying sb contents, we need to use lock its buffer.

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
---
 fs/f2fs/file.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index a018ed3..294e715 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -1591,14 +1591,18 @@ static int f2fs_ioc_get_encryption_pwsalt(struct file *filp, unsigned long arg)
 		return err;
 
 	/* update superblock with uuid */
+	lock_buffer(sbi->raw_super_buf);
 	generate_random_uuid(sbi->raw_super->encrypt_pw_salt);
+	unlock_buffer(sbi->raw_super_buf);
 
 	err = f2fs_commit_super(sbi, false);
 
 	mnt_drop_write_file(filp);
 	if (err) {
 		/* undo new data */
+		lock_buffer(sbi->raw_super_buf);
 		memset(sbi->raw_super->encrypt_pw_salt, 0, 16);
+		unlock_buffer(sbi->raw_super_buf);
 		return err;
 	}
 got_it:
-- 
2.4.9 (Apple Git-60)


------------------------------------------------------------------------------

RE: [f2fs-dev] [PATCH 1/3] f2fs: enhance the bit operation for SSR

[Chao Yu]

> -----Original Message-----
> From: Jaegeuk Kim [mailto:jaegeuk@kernel.org]
> Sent: Tuesday, December 08, 2015 6:53 AM
> To: linux-kernel@vger.kernel.org; linux-fsdevel@vger.kernel.org;
> linux-f2fs-devel@lists.sourceforge.net
> Cc: Jaegeuk Kim
> Subject: [f2fs-dev] [PATCH 1/3] f2fs: enhance the bit operation for SSR
> 
> This patch enhances the existing bit operation when f2fs allocates SSR
> blocks.
> 
> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

Reviewed-by: Chao Yu <chao2.yu@samsung.com>

Re: [PATCH 1/3] f2fs: enhance the bit operation for SSR

[Chao Yu]

> -----Original Message-----
> From: Jaegeuk Kim [mailto:jaegeuk@kernel.org]
> Sent: Tuesday, December 08, 2015 6:53 AM
> To: linux-kernel@vger.kernel.org; linux-fsdevel@vger.kernel.org;
> linux-f2fs-devel@lists.sourceforge.net
> Cc: Jaegeuk Kim
> Subject: [f2fs-dev] [PATCH 1/3] f2fs: enhance the bit operation for SSR
> 
> This patch enhances the existing bit operation when f2fs allocates SSR
> blocks.
> 
> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

Reviewed-by: Chao Yu <chao2.yu@samsung.com>


------------------------------------------------------------------------------