[PATCH] btrfs: Improve btrfs_search_slot description

[PATCH] btrfs: Improve btrfs_search_slot description

[Nikolay Borisov]

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
---
 fs/btrfs/ctree.c | 32 ++++++++++++++++++++++----------
 1 file changed, 22 insertions(+), 10 deletions(-)

diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index 880f4f693263..1f001d31bda8 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -2653,18 +2653,30 @@ int btrfs_find_item(struct btrfs_root *fs_root, struct btrfs_path *path,
 	return 0;
 }
 
-/*
- * look for key in the tree.  path is filled in with nodes along the way
- * if key is found, we return zero and you can find the item in the leaf
- * level of the path (level 0)
+/* btrfs_search_slot - look for a key in a tree and perform necessary
+ * modifications to preserve tree invariants.
+ *
+ * @trans:	Handle of transaction, used when modifying the tree
+ * @p:		Holds all btree nodes along the search path
+ * @root:	The root node of the tree
+ * @key:	The key we are looking for
+ * @ins_len:	Indicates purpose of search, for inserts it is 1, for
+ *		deletions it's -1. 0 for plain searches
+ * @cow:	boolean should CoW operations be performed. Must always be 1
+ *		when modifying the tree.
+ *
+ * If @ins_len > 0, nodes and leaves will be split as we walk down the tree.
+ * If @ins_len < 0, nodes will be merged as we walk down the tree (if possible)
+ *
+ * If @key is found, 0 is returned and you can find the item in the leaf level
+ * of the path (level 0)
  *
- * If the key isn't found, the path points to the slot where it should
- * be inserted, and 1 is returned.  If there are other errors during the
- * search a negative error number is returned.
+ * If @key isn't found, 1 is returned and the leaf level of the path (level 0)
+ * points to the slot where it should be inserted
+ * be inserted, and 1 is returned.
  *
- * if ins_len > 0, nodes and leaves will be split as we walk down the
- * tree.  if ins_len < 0, nodes will be merged as we walk down the tree (if
- * possible)
+ * If an error is encountered while searching the tree a negative error number
+ * is returned
  */
 int btrfs_search_slot(struct btrfs_trans_handle *trans, struct btrfs_root *root,
 		      const struct btrfs_key *key, struct btrfs_path *p,
-- 
2.7.4

Re: [PATCH] btrfs: Improve btrfs_search_slot description

[David Sterba]

On Fri, Dec 08, 2017 at 05:06:25PM +0200, Nikolay Borisov wrote:
> Signed-off-by: Nikolay Borisov <nborisov@suse.com>
> ---
>  fs/btrfs/ctree.c | 32 ++++++++++++++++++++++----------
>  1 file changed, 22 insertions(+), 10 deletions(-)
> 
> diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
> index 880f4f693263..1f001d31bda8 100644
> --- a/fs/btrfs/ctree.c
> +++ b/fs/btrfs/ctree.c
> @@ -2653,18 +2653,30 @@ int btrfs_find_item(struct btrfs_root *fs_root, struct btrfs_path *path,
>  	return 0;
>  }
>  
> -/*
> - * look for key in the tree.  path is filled in with nodes along the way
> - * if key is found, we return zero and you can find the item in the leaf
> - * level of the path (level 0)
> +/* btrfs_search_slot - look for a key in a tree and perform necessary

 /*
  * ...

> + * modifications to preserve tree invariants.
> + *
> + * @trans:	Handle of transaction, used when modifying the tree
> + * @p:		Holds all btree nodes along the search path
> + * @root:	The root node of the tree
> + * @key:	The key we are looking for
> + * @ins_len:	Indicates purpose of search, for inserts it is 1, for
> + *		deletions it's -1. 0 for plain searches
> + * @cow:	boolean should CoW operations be performed. Must always be 1
> + *		when modifying the tree.
> + *
> + * If @ins_len > 0, nodes and leaves will be split as we walk down the tree.
> + * If @ins_len < 0, nodes will be merged as we walk down the tree (if possible)
> + *
> + * If @key is found, 0 is returned and you can find the item in the leaf level
> + * of the path (level 0)
>   *
> - * If the key isn't found, the path points to the slot where it should
> - * be inserted, and 1 is returned.  If there are other errors during the
> - * search a negative error number is returned.
> + * If @key isn't found, 1 is returned and the leaf level of the path (level 0)
> + * points to the slot where it should be inserted
> + * be inserted, and 1 is returned.

looks like some editing artifact

>   *
> - * if ins_len > 0, nodes and leaves will be split as we walk down the
> - * tree.  if ins_len < 0, nodes will be merged as we walk down the tree (if
> - * possible)
> + * If an error is encountered while searching the tree a negative error number
> + * is returned
>   */
>  int btrfs_search_slot(struct btrfs_trans_handle *trans, struct btrfs_root *root,
>  		      const struct btrfs_key *key, struct btrfs_path *p,
> -- 
> 2.7.4
> 
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[PATCH v2] btrfs: Improve btrfs_search_slot description

[Nikolay Borisov]

Signed-off-by: Nikolay Borisov <nborisov@suse.com>
---
 fs/btrfs/ctree.c | 30 +++++++++++++++++++++---------
 1 file changed, 21 insertions(+), 9 deletions(-)

diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c
index 880f4f693263..7e6511dfe73a 100644
--- a/fs/btrfs/ctree.c
+++ b/fs/btrfs/ctree.c
@@ -2654,17 +2654,29 @@ int btrfs_find_item(struct btrfs_root *fs_root, struct btrfs_path *path,
 }
 
 /*
- * look for key in the tree.  path is filled in with nodes along the way
- * if key is found, we return zero and you can find the item in the leaf
- * level of the path (level 0)
+ * btrfs_search_slot - look for a key in a tree and perform necessary
+ * modifications to preserve tree invariants.
  *
- * If the key isn't found, the path points to the slot where it should
- * be inserted, and 1 is returned.  If there are other errors during the
- * search a negative error number is returned.
+ * @trans:	Handle of transaction, used when modifying the tree
+ * @p:		Holds all btree nodes along the search path
+ * @root:	The root node of the tree
+ * @key:	The key we are looking for
+ * @ins_len:	Indicates purpose of search, for inserts it is 1, for
+ *		deletions it's -1. 0 for plain searches
+ * @cow:	boolean should CoW operations be performed. Must always be 1
+ *		when modifying the tree.
  *
- * if ins_len > 0, nodes and leaves will be split as we walk down the
- * tree.  if ins_len < 0, nodes will be merged as we walk down the tree (if
- * possible)
+ * If @ins_len > 0, nodes and leaves will be split as we walk down the tree.
+ * If @ins_len < 0, nodes will be merged as we walk down the tree (if possible)
+ *
+ * If @key is found, 0 is returned and you can find the item in the leaf level
+ * of the path (level 0)
+ *
+ * If @key isn't found, 1 is returned and the leaf level of the path (level 0)
+ * points to the slot where it should be inserted
+ *
+ * If an error is encountered while searching the tree a negative error number
+ * is returned
  */
 int btrfs_search_slot(struct btrfs_trans_handle *trans, struct btrfs_root *root,
 		      const struct btrfs_key *key, struct btrfs_path *p,
-- 
2.7.4

Re: [PATCH v2] btrfs: Improve btrfs_search_slot description

[David Sterba]

On Wed, Dec 13, 2017 at 09:38:14AM +0200, Nikolay Borisov wrote:
> Signed-off-by: Nikolay Borisov <nborisov@suse.com>

Added, thanks.