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author | Chris Mason <chris.mason@oracle.com> | 2008-07-17 13:53:27 -0400 |
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committer | Chris Mason <chris.mason@oracle.com> | 2008-09-25 11:04:05 -0400 |
commit | eb84ae039e10f1f80443d846ba1350122bbdc753 (patch) | |
tree | d87bcbead436eaf96f5160ac46f78699d65c5251 /fs/btrfs/ordered-data.h | |
parent | 54641bd17db9fbfc13c7b1d4ee0dd2713bf3e076 (diff) | |
download | kernel_samsung_smdk4412-eb84ae039e10f1f80443d846ba1350122bbdc753.zip kernel_samsung_smdk4412-eb84ae039e10f1f80443d846ba1350122bbdc753.tar.gz kernel_samsung_smdk4412-eb84ae039e10f1f80443d846ba1350122bbdc753.tar.bz2 |
Btrfs: Cleanup and comment ordered-data.c
Signed-off-by: Chris Mason <chris.mason@oracle.com>
Diffstat (limited to 'fs/btrfs/ordered-data.h')
-rw-r--r-- | fs/btrfs/ordered-data.h | 49 |
1 files changed, 41 insertions, 8 deletions
diff --git a/fs/btrfs/ordered-data.h b/fs/btrfs/ordered-data.h index 33f0d9e..98f491d 100644 --- a/fs/btrfs/ordered-data.h +++ b/fs/btrfs/ordered-data.h @@ -19,12 +19,19 @@ #ifndef __BTRFS_ORDERED_DATA__ #define __BTRFS_ORDERED_DATA__ +/* one of these per inode */ struct btrfs_ordered_inode_tree { struct mutex mutex; struct rb_root tree; struct rb_node *last; }; +/* + * these are used to collect checksums done just before bios submission. + * They are attached via a list into the ordered extent, and + * checksum items are inserted into the tree after all the blocks in + * the ordered extent are on disk + */ struct btrfs_sector_sum { u64 offset; u32 sum; @@ -34,27 +41,56 @@ struct btrfs_ordered_sum { u64 file_offset; u64 len; struct list_head list; + /* last field is a variable length array of btrfs_sector_sums */ struct btrfs_sector_sum sums; }; -/* bits for the flags field */ +/* + * bits for the flags field: + * + * BTRFS_ORDERED_IO_DONE is set when all of the blocks are written. + * It is used to make sure metadata is inserted into the tree only once + * per extent. + * + * BTRFS_ORDERED_COMPLETE is set when the extent is removed from the + * rbtree, just before waking any waiters. It is used to indicate the + * IO is done and any metadata is inserted into the tree. + */ #define BTRFS_ORDERED_IO_DONE 0 /* set when all the pages are written */ + #define BTRFS_ORDERED_COMPLETE 1 /* set when removed from the tree */ -#define BTRFS_ORDERED_START 2 /* set when tree setup */ struct btrfs_ordered_extent { + /* logical offset in the file */ u64 file_offset; + + /* disk byte number */ u64 start; + + /* length of the extent in bytes */ u64 len; + + /* flags (described above) */ unsigned long flags; + + /* reference count */ atomic_t refs; + + /* list of checksums for insertion when the extent io is done */ struct list_head list; - struct inode *inode; + + /* used to wait for the BTRFS_ORDERED_COMPLETE bit */ wait_queue_head_t wait; + + /* our friendly rbtree entry */ struct rb_node rb_node; }; +/* + * calculates the total size you need to allocate for an ordered sum + * structure spanning 'bytes' in the file + */ static inline int btrfs_ordered_sum_size(struct btrfs_root *root, u64 bytes) { unsigned long num_sectors = (bytes + root->sectorsize - 1) / @@ -81,14 +117,11 @@ int btrfs_add_ordered_extent(struct inode *inode, u64 file_offset, int btrfs_add_ordered_sum(struct inode *inode, struct btrfs_ordered_sum *sum); struct btrfs_ordered_extent *btrfs_lookup_ordered_extent(struct inode *inode, u64 file_offset); -void btrfs_wait_ordered_extent(struct inode *inode, - struct btrfs_ordered_extent *entry); +void btrfs_start_ordered_extent(struct inode *inode, + struct btrfs_ordered_extent *entry, int wait); void btrfs_wait_ordered_range(struct inode *inode, u64 start, u64 len); struct btrfs_ordered_extent * btrfs_lookup_first_ordered_extent(struct inode * inode, u64 file_offset); -int btrfs_add_ordered_pending(struct inode *inode, - struct btrfs_ordered_extent *ordered, - u64 start, u64 len); int btrfs_ordered_update_i_size(struct inode *inode, struct btrfs_ordered_extent *ordered); int btrfs_find_ordered_sum(struct inode *inode, u64 offset, u32 *sum); |