From d352ac68148b69937d39ca5d48bcc4478e118dbf Mon Sep 17 00:00:00 2001 From: Chris Mason Date: Mon, 29 Sep 2008 15:18:18 -0400 Subject: 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 --- fs/btrfs/btrfs_inode.h | 54 +++++++++++++++++++++++++++++++++++++++++++++++--- 1 file changed, 51 insertions(+), 3 deletions(-) (limited to 'fs/btrfs/btrfs_inode.h') diff --git a/fs/btrfs/btrfs_inode.h b/fs/btrfs/btrfs_inode.h index 0577fda2168..0b2e623cf42 100644 --- a/fs/btrfs/btrfs_inode.h +++ b/fs/btrfs/btrfs_inode.h @@ -25,27 +25,58 @@ /* in memory btrfs inode */ struct btrfs_inode { + /* which subvolume this inode belongs to */ struct btrfs_root *root; + + /* the block group preferred for allocations. This pointer is buggy + * and needs to be replaced with a bytenr instead + */ struct btrfs_block_group_cache *block_group; + + /* key used to find this inode on disk. This is used by the code + * to read in roots of subvolumes + */ struct btrfs_key location; + + /* the extent_tree has caches of all the extent mappings to disk */ struct extent_map_tree extent_tree; + + /* the io_tree does range state (DIRTY, LOCKED etc) */ struct extent_io_tree io_tree; + + /* special utility tree used to record which mirrors have already been + * tried when checksums fail for a given block + */ struct extent_io_tree io_failure_tree; + + /* held while inserting checksums to avoid races */ struct mutex csum_mutex; + + /* held while inesrting or deleting extents from files */ struct mutex extent_mutex; + + /* held while logging the inode in tree-log.c */ struct mutex log_mutex; - struct inode vfs_inode; + + /* used to order data wrt metadata */ struct btrfs_ordered_inode_tree ordered_tree; + /* standard acl pointers */ struct posix_acl *i_acl; struct posix_acl *i_default_acl; /* for keeping track of orphaned inodes */ struct list_head i_orphan; + /* list of all the delalloc inodes in the FS. There are times we need + * to write all the delalloc pages to disk, and this list is used + * to walk them all. + */ struct list_head delalloc_inodes; - /* full 64 bit generation number */ + /* full 64 bit generation number, struct vfs_inode doesn't have a big + * enough field for this. + */ u64 generation; /* @@ -57,10 +88,25 @@ struct btrfs_inode { */ u64 logged_trans; - /* trans that last made a change that should be fully fsync'd */ + /* + * trans that last made a change that should be fully fsync'd. This + * gets reset to zero each time the inode is logged + */ u64 log_dirty_trans; + + /* total number of bytes pending delalloc, used by stat to calc the + * real block usage of the file + */ u64 delalloc_bytes; + + /* + * the size of the file stored in the metadata on disk. data=ordered + * means the in-memory i_size might be larger than the size on disk + * because not all the blocks are written yet. + */ u64 disk_i_size; + + /* flags field from the on disk inode */ u32 flags; /* @@ -68,6 +114,8 @@ struct btrfs_inode { * number for new files that are created */ u64 index_cnt; + + struct inode vfs_inode; }; static inline struct btrfs_inode *BTRFS_I(struct inode *inode) -- cgit v1.2.3