[PATCH 1/3] f2fs: early check broken symlink length in the encrypted case

[PATCH 1/3] f2fs: early check broken symlink length in the encrypted case

[Jaegeuk Kim]

If link is broken, its len is zero, and we don't need to move forward.

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
---
 fs/f2fs/namei.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/fs/f2fs/namei.c b/fs/f2fs/namei.c
index fb41c80..5cc4128 100644
--- a/fs/f2fs/namei.c
+++ b/fs/f2fs/namei.c
@@ -931,7 +931,7 @@ static const char *f2fs_encrypted_follow_link(struct dentry *dentry, void **cook
 {
 	struct page *cpage = NULL;
 	char *caddr, *paddr = NULL;
-	struct f2fs_str cstr;
+	struct f2fs_str cstr = FSTR_INIT(NULL, 0);
 	struct f2fs_str pstr = FSTR_INIT(NULL, 0);
 	struct inode *inode = d_inode(dentry);
 	struct f2fs_encrypted_symlink_data *sd;
@@ -952,6 +952,12 @@ static const char *f2fs_encrypted_follow_link(struct dentry *dentry, void **cook
 	/* Symlink is encrypted */
 	sd = (struct f2fs_encrypted_symlink_data *)caddr;
 	cstr.len = le16_to_cpu(sd->len);
+
+	/* this is broken symlink case */
+	if (cstr.len == 0) {
+		res = -ENOENT;
+		goto errout;
+	}
 	cstr.name = kmalloc(cstr.len, GFP_NOFS);
 	if (!cstr.name) {
 		res = -ENOMEM;
@@ -960,7 +966,7 @@ static const char *f2fs_encrypted_follow_link(struct dentry *dentry, void **cook
 	memcpy(cstr.name, sd->encrypted_path, cstr.len);
 
 	/* this is broken symlink case */
-	if (cstr.name[0] == 0 && cstr.len == 0) {
+	if (cstr.name[0] == 0) {
 		res = -ENOENT;
 		goto errout;
 	}
-- 
2.5.4 (Apple Git-61)

[PATCH 2/3] f2fs: use i_size_read to get i_size

[Jaegeuk Kim]

We need to use i_size_read() to get inode->i_size.

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
---
 fs/f2fs/data.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index f34f42a..8a89810 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -1386,10 +1386,11 @@ skip_write:
 static void f2fs_write_failed(struct address_space *mapping, loff_t to)
 {
 	struct inode *inode = mapping->host;
+	loff_t i_size = i_size_read(inode);
 
-	if (to > inode->i_size) {
-		truncate_pagecache(inode, inode->i_size);
-		truncate_blocks(inode, inode->i_size, true);
+	if (to > i_size) {
+		truncate_pagecache(inode, i_size);
+		truncate_blocks(inode, i_size, true);
 	}
 }
 
-- 
2.5.4 (Apple Git-61)

RE: [f2fs-dev] [PATCH 2/3] f2fs: use i_size_read to get i_size

[Chao Yu]

Hi Jaegeuk,

> -----Original Message-----
> From: Jaegeuk Kim [mailto:jaegeuk@kernel.org]
> Sent: Tuesday, December 29, 2015 7:32 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: use i_size_read to get i_size
> 
> We need to use i_size_read() to get inode->i_size.

All callers of f2fs_write_failed should be protected by i_mutex, so no
one can change i_size, do we really need to use i_size_read here?

Thanks,

> 
> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
> ---
>  fs/f2fs/data.c | 7 ++++---
>  1 file changed, 4 insertions(+), 3 deletions(-)
> 
> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
> index f34f42a..8a89810 100644
> --- a/fs/f2fs/data.c
> +++ b/fs/f2fs/data.c
> @@ -1386,10 +1386,11 @@ skip_write:
>  static void f2fs_write_failed(struct address_space *mapping, loff_t to)
>  {
>  	struct inode *inode = mapping->host;
> +	loff_t i_size = i_size_read(inode);
> 
> -	if (to > inode->i_size) {
> -		truncate_pagecache(inode, inode->i_size);
> -		truncate_blocks(inode, inode->i_size, true);
> +	if (to > i_size) {
> +		truncate_pagecache(inode, i_size);
> +		truncate_blocks(inode, i_size, true);
>  	}
>  }
> 
> --
> 2.5.4 (Apple Git-61)
> 
> 
> ------------------------------------------------------------------------------
> _______________________________________________
> Linux-f2fs-devel mailing list
> Linux-f2fs-devel@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel

Re: [f2fs-dev] [PATCH 2/3] f2fs: use i_size_read to get i_size

[Jaegeuk Kim]

Hi Chao,

On Tue, Dec 29, 2015 at 05:18:19PM +0800, Chao Yu wrote:
> Hi Jaegeuk,
> 
> > -----Original Message-----
> > From: Jaegeuk Kim [mailto:jaegeuk@kernel.org]
> > Sent: Tuesday, December 29, 2015 7:32 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: use i_size_read to get i_size
> > 
> > We need to use i_size_read() to get inode->i_size.
> 
> All callers of f2fs_write_failed should be protected by i_mutex, so no
> one can change i_size, do we really need to use i_size_read here?

Just to follow convention and avoid any confusion later.
We also use i_size_read/write consistently across whole areas.

Thanks,

> 
> Thanks,
> 
> > 
> > Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
> > ---
> >  fs/f2fs/data.c | 7 ++++---
> >  1 file changed, 4 insertions(+), 3 deletions(-)
> > 
> > diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
> > index f34f42a..8a89810 100644
> > --- a/fs/f2fs/data.c
> > +++ b/fs/f2fs/data.c
> > @@ -1386,10 +1386,11 @@ skip_write:
> >  static void f2fs_write_failed(struct address_space *mapping, loff_t to)
> >  {
> >  	struct inode *inode = mapping->host;
> > +	loff_t i_size = i_size_read(inode);
> > 
> > -	if (to > inode->i_size) {
> > -		truncate_pagecache(inode, inode->i_size);
> > -		truncate_blocks(inode, inode->i_size, true);
> > +	if (to > i_size) {
> > +		truncate_pagecache(inode, i_size);
> > +		truncate_blocks(inode, i_size, true);
> >  	}
> >  }
> > 
> > --
> > 2.5.4 (Apple Git-61)
> > 
> > 
> > ------------------------------------------------------------------------------
> > _______________________________________________
> > Linux-f2fs-devel mailing list
> > Linux-f2fs-devel@lists.sourceforge.net
> > https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel

[PATCH 3/3] f2fs: load largest extent all the time

[Jaegeuk Kim]

Otherwise, we can get mismatched largest extent information.

One example is:
1. mount f2fs w/ extent_cache
2. make a small extent
3. umount
4. mount f2fs w/o extent_cache
5. update the largest extent
6. umount
7. mount f2fs w/ extent_cache
8. get the old extent made by #2

Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
---
 fs/f2fs/extent_cache.c | 18 +++++++++++++-----
 fs/f2fs/f2fs.h         |  2 +-
 fs/f2fs/inode.c        |  3 ++-
 3 files changed, 16 insertions(+), 7 deletions(-)

diff --git a/fs/f2fs/extent_cache.c b/fs/f2fs/extent_cache.c
index e7b6548..23e7c82 100644
--- a/fs/f2fs/extent_cache.c
+++ b/fs/f2fs/extent_cache.c
@@ -166,20 +166,27 @@ static void __drop_largest_extent(struct inode *inode,
 		largest->len = 0;
 }
 
-void f2fs_init_extent_tree(struct inode *inode, struct f2fs_extent *i_ext)
+/* return true, if inode page is changed */
+bool f2fs_init_extent_tree(struct inode *inode, struct f2fs_extent *i_ext)
 {
 	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
 	struct extent_tree *et;
 	struct extent_node *en;
 	struct extent_info ei;
 
-	if (!f2fs_may_extent_tree(inode))
-		return;
+	if (!f2fs_may_extent_tree(inode)) {
+		/* drop largest extent */
+		if (i_ext && i_ext->len) {
+			i_ext->len = 0;
+			return true;
+		}
+		return false;
+	}
 
 	et = __grab_extent_tree(inode);
 
-	if (!i_ext || le32_to_cpu(i_ext->len) < F2FS_MIN_EXTENT_LEN)
-		return;
+	if (!i_ext || !i_ext->len)
+		return false;
 
 	set_extent_info(&ei, le32_to_cpu(i_ext->fofs),
 		le32_to_cpu(i_ext->blk), le32_to_cpu(i_ext->len));
@@ -196,6 +203,7 @@ void f2fs_init_extent_tree(struct inode *inode, struct f2fs_extent *i_ext)
 	}
 out:
 	write_unlock(&et->lock);
+	return false;
 }
 
 static bool f2fs_lookup_extent_tree(struct inode *inode, pgoff_t pgofs,
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index e04b2be..a339508 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -2083,7 +2083,7 @@ void f2fs_leave_shrinker(struct f2fs_sb_info *);
  * extent_cache.c
  */
 unsigned int f2fs_shrink_extent_tree(struct f2fs_sb_info *, int);
-void f2fs_init_extent_tree(struct inode *, struct f2fs_extent *);
+bool f2fs_init_extent_tree(struct inode *, struct f2fs_extent *);
 unsigned int f2fs_destroy_extent_node(struct inode *);
 void f2fs_destroy_extent_tree(struct inode *);
 bool f2fs_lookup_extent_cache(struct inode *, pgoff_t, struct extent_info *);
diff --git a/fs/f2fs/inode.c b/fs/f2fs/inode.c
index ec3fb32..e955008 100644
--- a/fs/f2fs/inode.c
+++ b/fs/f2fs/inode.c
@@ -138,7 +138,8 @@ static int do_read_inode(struct inode *inode)
 	fi->i_pino = le32_to_cpu(ri->i_pino);
 	fi->i_dir_level = ri->i_dir_level;
 
-	f2fs_init_extent_tree(inode, &ri->i_ext);
+	if (f2fs_init_extent_tree(inode, &ri->i_ext))
+		set_page_dirty(node_page);
 
 	get_inline_info(fi, ri);
 
-- 
2.5.4 (Apple Git-61)

RE: [f2fs-dev] [PATCH 3/3] f2fs: load largest extent all the time

[Chao Yu]

Hi Jaegeuk,

> -----Original Message-----
> From: Jaegeuk Kim [mailto:jaegeuk@kernel.org]
> Sent: Tuesday, December 29, 2015 7:32 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: load largest extent all the time
> 
> Otherwise, we can get mismatched largest extent information.
> 
> One example is:
> 1. mount f2fs w/ extent_cache
> 2. make a small extent
> 3. umount
> 4. mount f2fs w/o extent_cache
> 5. update the largest extent
> 6. umount
> 7. mount f2fs w/ extent_cache
> 8. get the old extent made by #2

Good catch!

It's a pity to drop it since it may provide some help if we
can reuse it.

Thanks,

> 
> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
> ---
>  fs/f2fs/extent_cache.c | 18 +++++++++++++-----
>  fs/f2fs/f2fs.h         |  2 +-
>  fs/f2fs/inode.c        |  3 ++-
>  3 files changed, 16 insertions(+), 7 deletions(-)
> 
> diff --git a/fs/f2fs/extent_cache.c b/fs/f2fs/extent_cache.c
> index e7b6548..23e7c82 100644
> --- a/fs/f2fs/extent_cache.c
> +++ b/fs/f2fs/extent_cache.c
> @@ -166,20 +166,27 @@ static void __drop_largest_extent(struct inode *inode,
>  		largest->len = 0;
>  }
> 
> -void f2fs_init_extent_tree(struct inode *inode, struct f2fs_extent *i_ext)
> +/* return true, if inode page is changed */
> +bool f2fs_init_extent_tree(struct inode *inode, struct f2fs_extent *i_ext)
>  {
>  	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
>  	struct extent_tree *et;
>  	struct extent_node *en;
>  	struct extent_info ei;
> 
> -	if (!f2fs_may_extent_tree(inode))
> -		return;
> +	if (!f2fs_may_extent_tree(inode)) {
> +		/* drop largest extent */
> +		if (i_ext && i_ext->len) {
> +			i_ext->len = 0;
> +			return true;
> +		}
> +		return false;
> +	}
> 
>  	et = __grab_extent_tree(inode);
> 
> -	if (!i_ext || le32_to_cpu(i_ext->len) < F2FS_MIN_EXTENT_LEN)
> -		return;
> +	if (!i_ext || !i_ext->len)
> +		return false;
> 
>  	set_extent_info(&ei, le32_to_cpu(i_ext->fofs),
>  		le32_to_cpu(i_ext->blk), le32_to_cpu(i_ext->len));
> @@ -196,6 +203,7 @@ void f2fs_init_extent_tree(struct inode *inode, struct f2fs_extent *i_ext)
>  	}
>  out:
>  	write_unlock(&et->lock);
> +	return false;
>  }
> 
>  static bool f2fs_lookup_extent_tree(struct inode *inode, pgoff_t pgofs,
> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
> index e04b2be..a339508 100644
> --- a/fs/f2fs/f2fs.h
> +++ b/fs/f2fs/f2fs.h
> @@ -2083,7 +2083,7 @@ void f2fs_leave_shrinker(struct f2fs_sb_info *);
>   * extent_cache.c
>   */
>  unsigned int f2fs_shrink_extent_tree(struct f2fs_sb_info *, int);
> -void f2fs_init_extent_tree(struct inode *, struct f2fs_extent *);
> +bool f2fs_init_extent_tree(struct inode *, struct f2fs_extent *);
>  unsigned int f2fs_destroy_extent_node(struct inode *);
>  void f2fs_destroy_extent_tree(struct inode *);
>  bool f2fs_lookup_extent_cache(struct inode *, pgoff_t, struct extent_info *);
> diff --git a/fs/f2fs/inode.c b/fs/f2fs/inode.c
> index ec3fb32..e955008 100644
> --- a/fs/f2fs/inode.c
> +++ b/fs/f2fs/inode.c
> @@ -138,7 +138,8 @@ static int do_read_inode(struct inode *inode)
>  	fi->i_pino = le32_to_cpu(ri->i_pino);
>  	fi->i_dir_level = ri->i_dir_level;
> 
> -	f2fs_init_extent_tree(inode, &ri->i_ext);
> +	if (f2fs_init_extent_tree(inode, &ri->i_ext))
> +		set_page_dirty(node_page);
> 
>  	get_inline_info(fi, ri);
> 
> --
> 2.5.4 (Apple Git-61)
> 
> 
> ------------------------------------------------------------------------------
> _______________________________________________
> 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] f2fs: load largest extent all the time

[Jaegeuk Kim]

Hi Chao,

On Tue, Dec 29, 2015 at 05:23:55PM +0800, Chao Yu wrote:
> Hi Jaegeuk,
> 
> > -----Original Message-----
> > From: Jaegeuk Kim [mailto:jaegeuk@kernel.org]
> > Sent: Tuesday, December 29, 2015 7:32 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: load largest extent all the time
> > 
> > Otherwise, we can get mismatched largest extent information.
> > 
> > One example is:
> > 1. mount f2fs w/ extent_cache
> > 2. make a small extent
> > 3. umount
> > 4. mount f2fs w/o extent_cache
> > 5. update the largest extent
> > 6. umount
> > 7. mount f2fs w/ extent_cache
> > 8. get the old extent made by #2
> 
> Good catch!
> 
> It's a pity to drop it since it may provide some help if we
> can reuse it.

Indeed, but I expect it's not a common case.

Thanks,

> 
> Thanks,
> 
> > 
> > Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
> > ---
> >  fs/f2fs/extent_cache.c | 18 +++++++++++++-----
> >  fs/f2fs/f2fs.h         |  2 +-
> >  fs/f2fs/inode.c        |  3 ++-
> >  3 files changed, 16 insertions(+), 7 deletions(-)
> > 
> > diff --git a/fs/f2fs/extent_cache.c b/fs/f2fs/extent_cache.c
> > index e7b6548..23e7c82 100644
> > --- a/fs/f2fs/extent_cache.c
> > +++ b/fs/f2fs/extent_cache.c
> > @@ -166,20 +166,27 @@ static void __drop_largest_extent(struct inode *inode,
> >  		largest->len = 0;
> >  }
> > 
> > -void f2fs_init_extent_tree(struct inode *inode, struct f2fs_extent *i_ext)
> > +/* return true, if inode page is changed */
> > +bool f2fs_init_extent_tree(struct inode *inode, struct f2fs_extent *i_ext)
> >  {
> >  	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
> >  	struct extent_tree *et;
> >  	struct extent_node *en;
> >  	struct extent_info ei;
> > 
> > -	if (!f2fs_may_extent_tree(inode))
> > -		return;
> > +	if (!f2fs_may_extent_tree(inode)) {
> > +		/* drop largest extent */
> > +		if (i_ext && i_ext->len) {
> > +			i_ext->len = 0;
> > +			return true;
> > +		}
> > +		return false;
> > +	}
> > 
> >  	et = __grab_extent_tree(inode);
> > 
> > -	if (!i_ext || le32_to_cpu(i_ext->len) < F2FS_MIN_EXTENT_LEN)
> > -		return;
> > +	if (!i_ext || !i_ext->len)
> > +		return false;
> > 
> >  	set_extent_info(&ei, le32_to_cpu(i_ext->fofs),
> >  		le32_to_cpu(i_ext->blk), le32_to_cpu(i_ext->len));
> > @@ -196,6 +203,7 @@ void f2fs_init_extent_tree(struct inode *inode, struct f2fs_extent *i_ext)
> >  	}
> >  out:
> >  	write_unlock(&et->lock);
> > +	return false;
> >  }
> > 
> >  static bool f2fs_lookup_extent_tree(struct inode *inode, pgoff_t pgofs,
> > diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
> > index e04b2be..a339508 100644
> > --- a/fs/f2fs/f2fs.h
> > +++ b/fs/f2fs/f2fs.h
> > @@ -2083,7 +2083,7 @@ void f2fs_leave_shrinker(struct f2fs_sb_info *);
> >   * extent_cache.c
> >   */
> >  unsigned int f2fs_shrink_extent_tree(struct f2fs_sb_info *, int);
> > -void f2fs_init_extent_tree(struct inode *, struct f2fs_extent *);
> > +bool f2fs_init_extent_tree(struct inode *, struct f2fs_extent *);
> >  unsigned int f2fs_destroy_extent_node(struct inode *);
> >  void f2fs_destroy_extent_tree(struct inode *);
> >  bool f2fs_lookup_extent_cache(struct inode *, pgoff_t, struct extent_info *);
> > diff --git a/fs/f2fs/inode.c b/fs/f2fs/inode.c
> > index ec3fb32..e955008 100644
> > --- a/fs/f2fs/inode.c
> > +++ b/fs/f2fs/inode.c
> > @@ -138,7 +138,8 @@ static int do_read_inode(struct inode *inode)
> >  	fi->i_pino = le32_to_cpu(ri->i_pino);
> >  	fi->i_dir_level = ri->i_dir_level;
> > 
> > -	f2fs_init_extent_tree(inode, &ri->i_ext);
> > +	if (f2fs_init_extent_tree(inode, &ri->i_ext))
> > +		set_page_dirty(node_page);
> > 
> >  	get_inline_info(fi, ri);
> > 
> > --
> > 2.5.4 (Apple Git-61)
> > 
> > 
> > ------------------------------------------------------------------------------
> > _______________________________________________
> > Linux-f2fs-devel mailing list
> > Linux-f2fs-devel@lists.sourceforge.net
> > https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel

RE: [f2fs-dev] [PATCH 1/3] f2fs: early check broken symlink length in the encrypted case

[Chao Yu]

Hi Jaegeuk,

> -----Original Message-----
> From: Jaegeuk Kim [mailto:jaegeuk@kernel.org]
> Sent: Tuesday, December 29, 2015 7:32 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: early check broken symlink length in the encrypted case
> 
> If link is broken, its len is zero, and we don't need to move forward.
> 
> Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
> ---
>  fs/f2fs/namei.c | 10 ++++++++--
>  1 file changed, 8 insertions(+), 2 deletions(-)
> 
> diff --git a/fs/f2fs/namei.c b/fs/f2fs/namei.c
> index fb41c80..5cc4128 100644
> --- a/fs/f2fs/namei.c
> +++ b/fs/f2fs/namei.c
> @@ -931,7 +931,7 @@ static const char *f2fs_encrypted_follow_link(struct dentry *dentry, void
> **cook
>  {
>  	struct page *cpage = NULL;
>  	char *caddr, *paddr = NULL;
> -	struct f2fs_str cstr;
> +	struct f2fs_str cstr = FSTR_INIT(NULL, 0);
>  	struct f2fs_str pstr = FSTR_INIT(NULL, 0);
>  	struct inode *inode = d_inode(dentry);
>  	struct f2fs_encrypted_symlink_data *sd;
> @@ -952,6 +952,12 @@ static const char *f2fs_encrypted_follow_link(struct dentry *dentry, void
> **cook
>  	/* Symlink is encrypted */
>  	sd = (struct f2fs_encrypted_symlink_data *)caddr;
>  	cstr.len = le16_to_cpu(sd->len);
> +
> +	/* this is broken symlink case */
> +	if (cstr.len == 0) {

This case seems rare, can we add unlikely here?

> +		res = -ENOENT;
> +		goto errout;
> +	}
>  	cstr.name = kmalloc(cstr.len, GFP_NOFS);
>  	if (!cstr.name) {
>  		res = -ENOMEM;
> @@ -960,7 +966,7 @@ static const char *f2fs_encrypted_follow_link(struct dentry *dentry, void
> **cook
>  	memcpy(cstr.name, sd->encrypted_path, cstr.len);
> 
>  	/* this is broken symlink case */
> -	if (cstr.name[0] == 0 && cstr.len == 0) {
> +	if (cstr.name[0] == 0) {

ditto.

Thanks,

>  		res = -ENOENT;
>  		goto errout;
>  	}
> --
> 2.5.4 (Apple Git-61)
> 
> 
> ------------------------------------------------------------------------------
> _______________________________________________
> Linux-f2fs-devel mailing list
> Linux-f2fs-devel@lists.sourceforge.net
> https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel

Re: [f2fs-dev] [PATCH 1/3] f2fs: early check broken symlink length in the encrypted case

[Jaegeuk Kim]

Hi Chao,

On Tue, Dec 29, 2015 at 09:52:49AM +0800, Chao Yu wrote:
> Hi Jaegeuk,
> 
> > -----Original Message-----
> > From: Jaegeuk Kim [mailto:jaegeuk@kernel.org]
> > Sent: Tuesday, December 29, 2015 7:32 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: early check broken symlink length in the encrypted case
> > 
> > If link is broken, its len is zero, and we don't need to move forward.
> > 
> > Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
> > ---
> >  fs/f2fs/namei.c | 10 ++++++++--
> >  1 file changed, 8 insertions(+), 2 deletions(-)
> > 
> > diff --git a/fs/f2fs/namei.c b/fs/f2fs/namei.c
> > index fb41c80..5cc4128 100644
> > --- a/fs/f2fs/namei.c
> > +++ b/fs/f2fs/namei.c
> > @@ -931,7 +931,7 @@ static const char *f2fs_encrypted_follow_link(struct dentry *dentry, void
> > **cook
> >  {
> >  	struct page *cpage = NULL;
> >  	char *caddr, *paddr = NULL;
> > -	struct f2fs_str cstr;
> > +	struct f2fs_str cstr = FSTR_INIT(NULL, 0);
> >  	struct f2fs_str pstr = FSTR_INIT(NULL, 0);
> >  	struct inode *inode = d_inode(dentry);
> >  	struct f2fs_encrypted_symlink_data *sd;
> > @@ -952,6 +952,12 @@ static const char *f2fs_encrypted_follow_link(struct dentry *dentry, void
> > **cook
> >  	/* Symlink is encrypted */
> >  	sd = (struct f2fs_encrypted_symlink_data *)caddr;
> >  	cstr.len = le16_to_cpu(sd->len);
> > +
> > +	/* this is broken symlink case */
> > +	if (cstr.len == 0) {
> 
> This case seems rare, can we add unlikely here?

Agreed.
Will change them.

Thanks,

> 
> > +		res = -ENOENT;
> > +		goto errout;
> > +	}
> >  	cstr.name = kmalloc(cstr.len, GFP_NOFS);
> >  	if (!cstr.name) {
> >  		res = -ENOMEM;
> > @@ -960,7 +966,7 @@ static const char *f2fs_encrypted_follow_link(struct dentry *dentry, void
> > **cook
> >  	memcpy(cstr.name, sd->encrypted_path, cstr.len);
> > 
> >  	/* this is broken symlink case */
> > -	if (cstr.name[0] == 0 && cstr.len == 0) {
> > +	if (cstr.name[0] == 0) {
> 
> ditto.
> 
> Thanks,
> 
> >  		res = -ENOENT;
> >  		goto errout;
> >  	}
> > --
> > 2.5.4 (Apple Git-61)
> > 
> > 
> > ------------------------------------------------------------------------------
> > _______________________________________________
> > Linux-f2fs-devel mailing list
> > Linux-f2fs-devel@lists.sourceforge.net
> > https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel