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authorChris Mason <chris.mason@oracle.com>2008-09-29 15:18:18 -0400
committerChris Mason <chris.mason@oracle.com>2008-09-29 15:18:18 -0400
commitd352ac68148b69937d39ca5d48bcc4478e118dbf (patch)
tree7951dd7311999d9e77766acdc7f8e93de97874d8 /fs/btrfs/dir-item.c
parent9a5e1ea1e1e539e244a54afffc330fc368376ab9 (diff)
downloadop-kernel-dev-d352ac68148b69937d39ca5d48bcc4478e118dbf.zip
op-kernel-dev-d352ac68148b69937d39ca5d48bcc4478e118dbf.tar.gz
Btrfs: add and improve comments
This improves the comments at the top of many functions. It didn't dive into the guts of functions because I was trying to avoid merging problems with the new allocator and back reference work. extent-tree.c and volumes.c were both skipped, and there is definitely more work todo in cleaning and commenting the code. Signed-off-by: Chris Mason <chris.mason@oracle.com>
Diffstat (limited to 'fs/btrfs/dir-item.c')
-rw-r--r--fs/btrfs/dir-item.c41
1 files changed, 41 insertions, 0 deletions
diff --git a/fs/btrfs/dir-item.c b/fs/btrfs/dir-item.c
index e4f3009..5040b71 100644
--- a/fs/btrfs/dir-item.c
+++ b/fs/btrfs/dir-item.c
@@ -21,6 +21,14 @@
#include "hash.h"
#include "transaction.h"
+/*
+ * insert a name into a directory, doing overflow properly if there is a hash
+ * collision. data_size indicates how big the item inserted should be. On
+ * success a struct btrfs_dir_item pointer is returned, otherwise it is
+ * an ERR_PTR.
+ *
+ * The name is not copied into the dir item, you have to do that yourself.
+ */
static struct btrfs_dir_item *insert_with_overflow(struct btrfs_trans_handle
*trans,
struct btrfs_root *root,
@@ -55,6 +63,10 @@ static struct btrfs_dir_item *insert_with_overflow(struct btrfs_trans_handle
return (struct btrfs_dir_item *)ptr;
}
+/*
+ * xattrs work a lot like directories, this inserts an xattr item
+ * into the tree
+ */
int btrfs_insert_xattr_item(struct btrfs_trans_handle *trans,
struct btrfs_root *root, const char *name,
u16 name_len, const void *data, u16 data_len,
@@ -109,6 +121,13 @@ int btrfs_insert_xattr_item(struct btrfs_trans_handle *trans,
return ret;
}
+/*
+ * insert a directory item in the tree, doing all the magic for
+ * both indexes. 'dir' indicates which objectid to insert it into,
+ * 'location' is the key to stuff into the directory item, 'type' is the
+ * type of the inode we're pointing to, and 'index' is the sequence number
+ * to use for the second index (if one is created).
+ */
int btrfs_insert_dir_item(struct btrfs_trans_handle *trans, struct btrfs_root
*root, const char *name, int name_len, u64 dir,
struct btrfs_key *location, u8 type, u64 index)
@@ -184,6 +203,11 @@ out:
return 0;
}
+/*
+ * lookup a directory item based on name. 'dir' is the objectid
+ * we're searching in, and 'mod' tells us if you plan on deleting the
+ * item (use mod < 0) or changing the options (use mod > 0)
+ */
struct btrfs_dir_item *btrfs_lookup_dir_item(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct btrfs_path *path, u64 dir,
@@ -222,6 +246,14 @@ struct btrfs_dir_item *btrfs_lookup_dir_item(struct btrfs_trans_handle *trans,
return btrfs_match_dir_item_name(root, path, name, name_len);
}
+/*
+ * lookup a directory item based on index. 'dir' is the objectid
+ * we're searching in, and 'mod' tells us if you plan on deleting the
+ * item (use mod < 0) or changing the options (use mod > 0)
+ *
+ * The name is used to make sure the index really points to the name you were
+ * looking for.
+ */
struct btrfs_dir_item *
btrfs_lookup_dir_index_item(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
@@ -282,6 +314,11 @@ struct btrfs_dir_item *btrfs_lookup_xattr(struct btrfs_trans_handle *trans,
return btrfs_match_dir_item_name(root, path, name, name_len);
}
+/*
+ * helper function to look at the directory item pointed to by 'path'
+ * this walks through all the entries in a dir item and finds one
+ * for a specific name.
+ */
struct btrfs_dir_item *btrfs_match_dir_item_name(struct btrfs_root *root,
struct btrfs_path *path,
const char *name, int name_len)
@@ -313,6 +350,10 @@ struct btrfs_dir_item *btrfs_match_dir_item_name(struct btrfs_root *root,
return NULL;
}
+/*
+ * given a pointer into a directory item, delete it. This
+ * handles items that have more than one entry in them.
+ */
int btrfs_delete_one_dir_name(struct btrfs_trans_handle *trans,
struct btrfs_root *root,
struct btrfs_path *path,
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