[PATCH 1/2] ext4: create function to read journal inode

[PATCH 1/2] ext4: create function to read journal inode

[Eric Whitney]

Factor out the code used in ext4_get_journal() to read a valid journal
inode from storage, enabling its reuse in other functions.

Signed-off-by: Eric Whitney <enwlinux@gmail.com>
---
 fs/ext4/super.c | 32 +++++++++++++++++++++++---------
 1 file changed, 23 insertions(+), 9 deletions(-)

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 50912cc..4b0ca25 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -78,6 +78,8 @@ static int ext4_feature_set_ok(struct super_block *sb, int readonly);
 static void ext4_destroy_lazyinit_thread(void);
 static void ext4_unregister_li_request(struct super_block *sb);
 static void ext4_clear_request_list(void);
+static struct inode *ext4_get_journal_inode(struct super_block *sb,
+					    unsigned int journal_inum);
 
 /*
  * Lock ordering
@@ -4237,18 +4239,16 @@ static void ext4_init_journal_params(struct super_block *sb, journal_t *journal)
 	write_unlock(&journal->j_state_lock);
 }
 
-static journal_t *ext4_get_journal(struct super_block *sb,
-				   unsigned int journal_inum)
+static struct inode *ext4_get_journal_inode(struct super_block *sb,
+					     unsigned int journal_inum)
 {
 	struct inode *journal_inode;
-	journal_t *journal;
-
-	BUG_ON(!ext4_has_feature_journal(sb));
-
-	/* First, test for the existence of a valid inode on disk.  Bad
-	 * things happen if we iget() an unused inode, as the subsequent
-	 * iput() will try to delete it. */
 
+	/*
+	 * Test for the existence of a valid inode on disk.  Bad things
+	 * happen if we iget() an unused inode, as the subsequent iput()
+	 * will try to delete it.
+	 */
 	journal_inode = ext4_iget(sb, journal_inum);
 	if (IS_ERR(journal_inode)) {
 		ext4_msg(sb, KERN_ERR, "no journal found");
@@ -4268,6 +4268,20 @@ static journal_t *ext4_get_journal(struct super_block *sb,
 		iput(journal_inode);
 		return NULL;
 	}
+	return journal_inode;
+}
+
+static journal_t *ext4_get_journal(struct super_block *sb,
+				   unsigned int journal_inum)
+{
+	struct inode *journal_inode;
+	journal_t *journal;
+
+	BUG_ON(!ext4_has_feature_journal(sb));
+
+	journal_inode = ext4_get_journal_inode(sb, journal_inum);
+	if (!journal_inode)
+		return NULL;
 
 	journal = jbd2_journal_init_inode(journal_inode);
 	if (!journal) {
-- 
2.1.4

Re: [PATCH 1/2] ext4: create function to read journal inode

[Jan Kara]

On Wed 21-09-16 21:14:50, Eric Whitney wrote:
> Factor out the code used in ext4_get_journal() to read a valid journal
> inode from storage, enabling its reuse in other functions.
> 
> Signed-off-by: Eric Whitney <enwlinux@gmail.com>

Looks good. You can add:

Reviewed-by: Jan Kara <jack@suse.cz>

BTW: I didn't see PATCH 2/2?

								Honza
> ---
>  fs/ext4/super.c | 32 +++++++++++++++++++++++---------
>  1 file changed, 23 insertions(+), 9 deletions(-)
> 
> diff --git a/fs/ext4/super.c b/fs/ext4/super.c
> index 50912cc..4b0ca25 100644
> --- a/fs/ext4/super.c
> +++ b/fs/ext4/super.c
> @@ -78,6 +78,8 @@ static int ext4_feature_set_ok(struct super_block *sb, int readonly);
>  static void ext4_destroy_lazyinit_thread(void);
>  static void ext4_unregister_li_request(struct super_block *sb);
>  static void ext4_clear_request_list(void);
> +static struct inode *ext4_get_journal_inode(struct super_block *sb,
> +					    unsigned int journal_inum);
>  
>  /*
>   * Lock ordering
> @@ -4237,18 +4239,16 @@ static void ext4_init_journal_params(struct super_block *sb, journal_t *journal)
>  	write_unlock(&journal->j_state_lock);
>  }
>  
> -static journal_t *ext4_get_journal(struct super_block *sb,
> -				   unsigned int journal_inum)
> +static struct inode *ext4_get_journal_inode(struct super_block *sb,
> +					     unsigned int journal_inum)
>  {
>  	struct inode *journal_inode;
> -	journal_t *journal;
> -
> -	BUG_ON(!ext4_has_feature_journal(sb));
> -
> -	/* First, test for the existence of a valid inode on disk.  Bad
> -	 * things happen if we iget() an unused inode, as the subsequent
> -	 * iput() will try to delete it. */
>  
> +	/*
> +	 * Test for the existence of a valid inode on disk.  Bad things
> +	 * happen if we iget() an unused inode, as the subsequent iput()
> +	 * will try to delete it.
> +	 */
>  	journal_inode = ext4_iget(sb, journal_inum);
>  	if (IS_ERR(journal_inode)) {
>  		ext4_msg(sb, KERN_ERR, "no journal found");
> @@ -4268,6 +4268,20 @@ static journal_t *ext4_get_journal(struct super_block *sb,
>  		iput(journal_inode);
>  		return NULL;
>  	}
> +	return journal_inode;
> +}
> +
> +static journal_t *ext4_get_journal(struct super_block *sb,
> +				   unsigned int journal_inum)
> +{
> +	struct inode *journal_inode;
> +	journal_t *journal;
> +
> +	BUG_ON(!ext4_has_feature_journal(sb));
> +
> +	journal_inode = ext4_get_journal_inode(sb, journal_inum);
> +	if (!journal_inode)
> +		return NULL;
>  
>  	journal = jbd2_journal_init_inode(journal_inode);
>  	if (!journal) {
> -- 
> 2.1.4
> 
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-- 
Jan Kara <jack@suse.com>
SUSE Labs, CR

Re: [PATCH 1/2] ext4: create function to read journal inode

[Eric Whitney]

* Jan Kara <jack@suse.cz>:
> On Wed 21-09-16 21:14:50, Eric Whitney wrote:
> > Factor out the code used in ext4_get_journal() to read a valid journal
> > inode from storage, enabling its reuse in other functions.
> > 
> > Signed-off-by: Eric Whitney <enwlinux@gmail.com>
> 
> Looks good. You can add:
> 
> Reviewed-by: Jan Kara <jack@suse.cz>
> 
> BTW: I didn't see PATCH 2/2?
> 

Yup, my mistake.  I reposted it earlier today - hopefully it's now visible.

Thanks for the review!

Eric

Re: [PATCH 1/2] ext4: create function to read journal inode

[Theodore Ts'o]

On Wed, Sep 21, 2016 at 09:14:50PM -0400, Eric Whitney wrote:
> Factor out the code used in ext4_get_journal() to read a valid journal
> inode from storage, enabling its reuse in other functions.
> 
> Signed-off-by: Eric Whitney <enwlinux@gmail.com>

Thanks, applied.

					- Ted