[PATCH] ext4: clean up comments in ext4-extents patch
Signed-off-by: Randy Dunlap <rdunlap@xenotime.net> Signed-off-by: Dave Kleikamp <shaggy@austin.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Randy Dunlap
Linus Torvalds
parent
471d4011a9
commit
d0d856e8bd
3 changed files with 157 additions and 127 deletions
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@ -44,7 +44,10 @@
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#include <asm/uaccess.h>
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/* this macro combines low and hi parts of phys. blocknr into ext4_fsblk_t */
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/*
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* ext_pblock:
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* combine low and high parts of physical block number into ext4_fsblk_t
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*/
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static inline ext4_fsblk_t ext_pblock(struct ext4_extent *ex)
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{
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ext4_fsblk_t block;
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@ -55,7 +58,10 @@ static inline ext4_fsblk_t ext_pblock(struct ext4_extent *ex)
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return block;
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}
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/* this macro combines low and hi parts of phys. blocknr into ext4_fsblk_t */
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/*
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* idx_pblock:
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* combine low and high parts of a leaf physical block number into ext4_fsblk_t
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*/
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static inline ext4_fsblk_t idx_pblock(struct ext4_extent_idx *ix)
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{
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ext4_fsblk_t block;
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@ -66,7 +72,11 @@ static inline ext4_fsblk_t idx_pblock(struct ext4_extent_idx *ix)
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return block;
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}
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/* the routine stores large phys. blocknr into extent breaking it into parts */
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/*
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* ext4_ext_store_pblock:
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* stores a large physical block number into an extent struct,
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* breaking it into parts
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*/
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static inline void ext4_ext_store_pblock(struct ext4_extent *ex, ext4_fsblk_t pb)
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{
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ex->ee_start = cpu_to_le32((unsigned long) (pb & 0xffffffff));
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@ -74,7 +84,11 @@ static inline void ext4_ext_store_pblock(struct ext4_extent *ex, ext4_fsblk_t pb
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ex->ee_start_hi = cpu_to_le16((unsigned long) ((pb >> 31) >> 1) & 0xffff);
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}
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/* the routine stores large phys. blocknr into index breaking it into parts */
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/*
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* ext4_idx_store_pblock:
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* stores a large physical block number into an index struct,
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* breaking it into parts
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*/
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static inline void ext4_idx_store_pblock(struct ext4_extent_idx *ix, ext4_fsblk_t pb)
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{
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ix->ei_leaf = cpu_to_le32((unsigned long) (pb & 0xffffffff));
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@ -179,8 +193,8 @@ static ext4_fsblk_t ext4_ext_find_goal(struct inode *inode,
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if ((ex = path[depth].p_ext))
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return ext_pblock(ex)+(block-le32_to_cpu(ex->ee_block));
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/* it looks index is empty
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* try to find starting from index itself */
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/* it looks like index is empty;
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* try to find starting block from index itself */
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if (path[depth].p_bh)
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return path[depth].p_bh->b_blocknr;
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}
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@ -317,7 +331,8 @@ static void ext4_ext_drop_refs(struct ext4_ext_path *path)
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}
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/*
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* binary search for closest index by given block
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* ext4_ext_binsearch_idx:
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* binary search for the closest index of the given block
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*/
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static void
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ext4_ext_binsearch_idx(struct inode *inode, struct ext4_ext_path *path, int block)
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@ -375,7 +390,8 @@ ext4_ext_binsearch_idx(struct inode *inode, struct ext4_ext_path *path, int bloc
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}
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/*
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* binary search for closest extent by given block
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* ext4_ext_binsearch:
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* binary search for closest extent of the given block
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*/
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static void
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ext4_ext_binsearch(struct inode *inode, struct ext4_ext_path *path, int block)
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@ -388,8 +404,8 @@ ext4_ext_binsearch(struct inode *inode, struct ext4_ext_path *path, int block)
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if (eh->eh_entries == 0) {
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/*
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* this leaf is empty yet:
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* we get such a leaf in split/add case
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* this leaf is empty:
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* we get such a leaf in split/add case
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*/
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return;
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}
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@ -520,8 +536,9 @@ ext4_ext_find_extent(struct inode *inode, int block, struct ext4_ext_path *path)
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}
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/*
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* insert new index [logical;ptr] into the block at cupr
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* it check where to insert: before curp or after curp
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* ext4_ext_insert_index:
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* insert new index [@logical;@ptr] into the block at @curp;
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* check where to insert: before @curp or after @curp
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*/
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static int ext4_ext_insert_index(handle_t *handle, struct inode *inode,
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struct ext4_ext_path *curp,
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@ -574,13 +591,14 @@ static int ext4_ext_insert_index(handle_t *handle, struct inode *inode,
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}
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/*
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* routine inserts new subtree into the path, using free index entry
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* at depth 'at:
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* - allocates all needed blocks (new leaf and all intermediate index blocks)
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* - makes decision where to split
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* - moves remaining extens and index entries (right to the split point)
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* into the newly allocated blocks
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* - initialize subtree
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* ext4_ext_split:
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* inserts new subtree into the path, using free index entry
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* at depth @at:
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* - allocates all needed blocks (new leaf and all intermediate index blocks)
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* - makes decision where to split
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* - moves remaining extents and index entries (right to the split point)
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* into the newly allocated blocks
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* - initializes subtree
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*/
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static int ext4_ext_split(handle_t *handle, struct inode *inode,
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struct ext4_ext_path *path,
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@ -598,14 +616,14 @@ static int ext4_ext_split(handle_t *handle, struct inode *inode,
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int err = 0;
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/* make decision: where to split? */
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/* FIXME: now desicion is simplest: at current extent */
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/* FIXME: now decision is simplest: at current extent */
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/* if current leaf will be splitted, then we should use
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/* if current leaf will be split, then we should use
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* border from split point */
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BUG_ON(path[depth].p_ext > EXT_MAX_EXTENT(path[depth].p_hdr));
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if (path[depth].p_ext != EXT_MAX_EXTENT(path[depth].p_hdr)) {
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border = path[depth].p_ext[1].ee_block;
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ext_debug("leaf will be splitted."
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ext_debug("leaf will be split."
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" next leaf starts at %d\n",
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le32_to_cpu(border));
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} else {
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@ -616,16 +634,16 @@ static int ext4_ext_split(handle_t *handle, struct inode *inode,
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}
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/*
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* if error occurs, then we break processing
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* and turn filesystem read-only. so, index won't
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* If error occurs, then we break processing
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* and mark filesystem read-only. index won't
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* be inserted and tree will be in consistent
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* state. next mount will repair buffers too
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* state. Next mount will repair buffers too.
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*/
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/*
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* get array to track all allocated blocks
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* we need this to handle errors and free blocks
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* upon them
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* Get array to track all allocated blocks.
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* We need this to handle errors and free blocks
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* upon them.
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*/
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ablocks = kmalloc(sizeof(ext4_fsblk_t) * depth, GFP_NOFS);
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if (!ablocks)
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@ -661,7 +679,7 @@ static int ext4_ext_split(handle_t *handle, struct inode *inode,
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neh->eh_depth = 0;
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ex = EXT_FIRST_EXTENT(neh);
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/* move remain of path[depth] to the new leaf */
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/* move remainder of path[depth] to the new leaf */
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BUG_ON(path[depth].p_hdr->eh_entries != path[depth].p_hdr->eh_max);
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/* start copy from next extent */
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/* TODO: we could do it by single memmove */
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@ -813,11 +831,12 @@ static int ext4_ext_split(handle_t *handle, struct inode *inode,
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}
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/*
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* routine implements tree growing procedure:
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* - allocates new block
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* - moves top-level data (index block or leaf) into the new block
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* - initialize new top-level, creating index that points to the
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* just created block
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* ext4_ext_grow_indepth:
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* implements tree growing procedure:
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* - allocates new block
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* - moves top-level data (index block or leaf) into the new block
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* - initializes new top-level, creating index that points to the
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* just created block
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*/
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static int ext4_ext_grow_indepth(handle_t *handle, struct inode *inode,
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struct ext4_ext_path *path,
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@ -892,8 +911,9 @@ static int ext4_ext_grow_indepth(handle_t *handle, struct inode *inode,
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}
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/*
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* routine finds empty index and adds new leaf. if no free index found
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* then it requests in-depth growing
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* ext4_ext_create_new_leaf:
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* finds empty index and adds new leaf.
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* if no free index is found, then it requests in-depth growing.
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*/
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static int ext4_ext_create_new_leaf(handle_t *handle, struct inode *inode,
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struct ext4_ext_path *path,
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@ -912,8 +932,8 @@ static int ext4_ext_create_new_leaf(handle_t *handle, struct inode *inode,
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curp--;
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}
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/* we use already allocated block for index block
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* so, subsequent data blocks should be contigoues */
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/* we use already allocated block for index block,
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* so subsequent data blocks should be contiguous */
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if (EXT_HAS_FREE_INDEX(curp)) {
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/* if we found index with free entry, then use that
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* entry: create all needed subtree and add new leaf */
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@ -943,12 +963,12 @@ static int ext4_ext_create_new_leaf(handle_t *handle, struct inode *inode,
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}
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/*
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* only first (depth 0 -> 1) produces free space
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* in all other cases we have to split growed tree
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* only first (depth 0 -> 1) produces free space;
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* in all other cases we have to split the grown tree
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*/
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depth = ext_depth(inode);
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if (path[depth].p_hdr->eh_entries == path[depth].p_hdr->eh_max) {
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/* now we need split */
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/* now we need to split */
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goto repeat;
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}
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}
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@ -958,10 +978,11 @@ static int ext4_ext_create_new_leaf(handle_t *handle, struct inode *inode,
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}
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/*
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* returns allocated block in subsequent extent or EXT_MAX_BLOCK
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* NOTE: it consider block number from index entry as
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* allocated block. thus, index entries have to be consistent
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* with leafs
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* ext4_ext_next_allocated_block:
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* returns allocated block in subsequent extent or EXT_MAX_BLOCK.
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* NOTE: it considers block number from index entry as
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* allocated block. Thus, index entries have to be consistent
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* with leaves.
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*/
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static unsigned long
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ext4_ext_next_allocated_block(struct ext4_ext_path *path)
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@ -993,6 +1014,7 @@ ext4_ext_next_allocated_block(struct ext4_ext_path *path)
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}
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/*
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* ext4_ext_next_leaf_block:
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* returns first allocated block from next leaf or EXT_MAX_BLOCK
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*/
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static unsigned ext4_ext_next_leaf_block(struct inode *inode,
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@ -1021,8 +1043,9 @@ static unsigned ext4_ext_next_leaf_block(struct inode *inode,
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}
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/*
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* if leaf gets modified and modified extent is first in the leaf
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* then we have to correct all indexes above
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* ext4_ext_correct_indexes:
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* if leaf gets modified and modified extent is first in the leaf,
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* then we have to correct all indexes above.
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* TODO: do we need to correct tree in all cases?
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*/
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int ext4_ext_correct_indexes(handle_t *handle, struct inode *inode,
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@ -1050,7 +1073,7 @@ int ext4_ext_correct_indexes(handle_t *handle, struct inode *inode,
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}
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/*
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* TODO: we need correction if border is smaller then current one
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* TODO: we need correction if border is smaller than current one
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*/
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k = depth - 1;
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border = path[depth].p_ext->ee_block;
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@ -1085,7 +1108,7 @@ ext4_can_extents_be_merged(struct inode *inode, struct ext4_extent *ex1,
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/*
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* To allow future support for preallocated extents to be added
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* as an RO_COMPAT feature, refuse to merge to extents if
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* can result in the top bit of ee_len being set
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* this can result in the top bit of ee_len being set.
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*/
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if (le16_to_cpu(ex1->ee_len) + le16_to_cpu(ex2->ee_len) > EXT_MAX_LEN)
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return 0;
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@ -1100,9 +1123,10 @@ ext4_can_extents_be_merged(struct inode *inode, struct ext4_extent *ex1,
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}
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/*
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* this routine tries to merge requsted extent into the existing
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* extent or inserts requested extent as new one into the tree,
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* creating new leaf in no-space case
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* ext4_ext_insert_extent:
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* tries to merge requsted extent into the existing extent or
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* inserts requested extent as new one into the tree,
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* creating new leaf in the no-space case.
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*/
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int ext4_ext_insert_extent(handle_t *handle, struct inode *inode,
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struct ext4_ext_path *path,
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@ -1163,8 +1187,8 @@ int ext4_ext_insert_extent(handle_t *handle, struct inode *inode,
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}
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/*
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* there is no free space in found leaf
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* we're gonna add new leaf in the tree
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* There is no free space in the found leaf.
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* We're gonna add a new leaf in the tree.
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*/
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err = ext4_ext_create_new_leaf(handle, inode, path, newext);
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if (err)
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@ -1377,7 +1401,8 @@ ext4_ext_put_in_cache(struct inode *inode, __u32 block,
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}
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/*
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* this routine calculate boundaries of the gap requested block fits into
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* ext4_ext_put_gap_in_cache:
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* calculate boundaries of the gap that the requested block fits into
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* and cache this gap
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*/
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static inline void
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@ -1452,9 +1477,10 @@ ext4_ext_in_cache(struct inode *inode, unsigned long block,
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}
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/*
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* routine removes index from the index block
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* it's used in truncate case only. thus all requests are for
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* last index in the block only
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* ext4_ext_rm_idx:
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* removes index from the index block.
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* It's used in truncate case only, thus all requests are for
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* last index in the block only.
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*/
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int ext4_ext_rm_idx(handle_t *handle, struct inode *inode,
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struct ext4_ext_path *path)
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@ -1480,11 +1506,12 @@ int ext4_ext_rm_idx(handle_t *handle, struct inode *inode,
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}
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/*
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* This routine returns max. credits extent tree can consume.
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* ext4_ext_calc_credits_for_insert:
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* This routine returns max. credits that the extent tree can consume.
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* It should be OK for low-performance paths like ->writepage()
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* To allow many writing process to fit a single transaction,
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* caller should calculate credits under truncate_mutex and
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* pass actual path.
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* To allow many writing processes to fit into a single transaction,
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* the caller should calculate credits under truncate_mutex and
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* pass the actual path.
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*/
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int inline ext4_ext_calc_credits_for_insert(struct inode *inode,
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struct ext4_ext_path *path)
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@ -1500,9 +1527,9 @@ int inline ext4_ext_calc_credits_for_insert(struct inode *inode,
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}
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/*
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* given 32bit logical block (4294967296 blocks), max. tree
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* given 32-bit logical block (4294967296 blocks), max. tree
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* can be 4 levels in depth -- 4 * 340^4 == 53453440000.
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* let's also add one more level for imbalance.
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* Let's also add one more level for imbalance.
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*/
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depth = 5;
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@ -1510,13 +1537,13 @@ int inline ext4_ext_calc_credits_for_insert(struct inode *inode,
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needed = 2;
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/*
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* tree can be full, so it'd need to grow in depth:
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* tree can be full, so it would need to grow in depth:
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* allocation + old root + new root
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*/
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needed += 2 + 1 + 1;
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/*
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* Index split can happen, we'd need:
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* Index split can happen, we would need:
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* allocate intermediate indexes (bitmap + group)
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* + change two blocks at each level, but root (already included)
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*/
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@ -1634,7 +1661,7 @@ ext4_ext_rm_leaf(handle_t *handle, struct inode *inode,
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BUG_ON(b != ex_ee_block + ex_ee_len - 1);
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}
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/* at present, extent can't cross block group */
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/* at present, extent can't cross block group: */
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/* leaf + bitmap + group desc + sb + inode */
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credits = 5;
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if (ex == EXT_FIRST_EXTENT(eh)) {
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@ -1660,7 +1687,7 @@ ext4_ext_rm_leaf(handle_t *handle, struct inode *inode,
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goto out;
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if (num == 0) {
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/* this extent is removed entirely mark slot unused */
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/* this extent is removed; mark slot entirely unused */
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ext4_ext_store_pblock(ex, 0);
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eh->eh_entries = cpu_to_le16(le16_to_cpu(eh->eh_entries)-1);
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}
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@ -1692,7 +1719,8 @@ ext4_ext_rm_leaf(handle_t *handle, struct inode *inode,
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}
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/*
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* returns 1 if current index have to be freed (even partial)
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* ext4_ext_more_to_rm:
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* returns 1 if current index has to be freed (even partial)
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*/
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static int inline
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ext4_ext_more_to_rm(struct ext4_ext_path *path)
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|
|
@ -1703,7 +1731,7 @@ ext4_ext_more_to_rm(struct ext4_ext_path *path)
|
|||
return 0;
|
||||
|
||||
/*
|
||||
* if truncate on deeper level happened it it wasn't partial
|
||||
* if truncate on deeper level happened, it wasn't partial,
|
||||
* so we have to consider current index for truncation
|
||||
*/
|
||||
if (le16_to_cpu(path->p_hdr->eh_entries) == path->p_block)
|
||||
|
|
@ -1729,8 +1757,8 @@ int ext4_ext_remove_space(struct inode *inode, unsigned long start)
|
|||
ext4_ext_invalidate_cache(inode);
|
||||
|
||||
/*
|
||||
* we start scanning from right side freeing all the blocks
|
||||
* after i_size and walking into the deep
|
||||
* We start scanning from right side, freeing all the blocks
|
||||
* after i_size and walking into the tree depth-wise.
|
||||
*/
|
||||
path = kmalloc(sizeof(struct ext4_ext_path) * (depth + 1), GFP_KERNEL);
|
||||
if (path == NULL) {
|
||||
|
|
@ -1749,7 +1777,7 @@ int ext4_ext_remove_space(struct inode *inode, unsigned long start)
|
|||
if (i == depth) {
|
||||
/* this is leaf block */
|
||||
err = ext4_ext_rm_leaf(handle, inode, path, start);
|
||||
/* root level have p_bh == NULL, brelse() eats this */
|
||||
/* root level has p_bh == NULL, brelse() eats this */
|
||||
brelse(path[i].p_bh);
|
||||
path[i].p_bh = NULL;
|
||||
i--;
|
||||
|
|
@ -1772,14 +1800,14 @@ int ext4_ext_remove_space(struct inode *inode, unsigned long start)
|
|||
BUG_ON(path[i].p_hdr->eh_magic != EXT4_EXT_MAGIC);
|
||||
|
||||
if (!path[i].p_idx) {
|
||||
/* this level hasn't touched yet */
|
||||
/* this level hasn't been touched yet */
|
||||
path[i].p_idx = EXT_LAST_INDEX(path[i].p_hdr);
|
||||
path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries)+1;
|
||||
ext_debug("init index ptr: hdr 0x%p, num %d\n",
|
||||
path[i].p_hdr,
|
||||
le16_to_cpu(path[i].p_hdr->eh_entries));
|
||||
} else {
|
||||
/* we've already was here, see at next index */
|
||||
/* we were already here, see at next index */
|
||||
path[i].p_idx--;
|
||||
}
|
||||
|
||||
|
|
@ -1799,19 +1827,19 @@ int ext4_ext_remove_space(struct inode *inode, unsigned long start)
|
|||
break;
|
||||
}
|
||||
|
||||
/* put actual number of indexes to know is this
|
||||
* number got changed at the next iteration */
|
||||
/* save actual number of indexes since this
|
||||
* number is changed at the next iteration */
|
||||
path[i].p_block = le16_to_cpu(path[i].p_hdr->eh_entries);
|
||||
i++;
|
||||
} else {
|
||||
/* we finish processing this index, go up */
|
||||
/* we finished processing this index, go up */
|
||||
if (path[i].p_hdr->eh_entries == 0 && i > 0) {
|
||||
/* index is empty, remove it
|
||||
/* index is empty, remove it;
|
||||
* handle must be already prepared by the
|
||||
* truncatei_leaf() */
|
||||
err = ext4_ext_rm_idx(handle, inode, path + i);
|
||||
}
|
||||
/* root level have p_bh == NULL, brelse() eats this */
|
||||
/* root level has p_bh == NULL, brelse() eats this */
|
||||
brelse(path[i].p_bh);
|
||||
path[i].p_bh = NULL;
|
||||
i--;
|
||||
|
|
@ -1822,8 +1850,8 @@ int ext4_ext_remove_space(struct inode *inode, unsigned long start)
|
|||
/* TODO: flexible tree reduction should be here */
|
||||
if (path->p_hdr->eh_entries == 0) {
|
||||
/*
|
||||
* truncate to zero freed all the tree
|
||||
* so, we need to correct eh_depth
|
||||
* truncate to zero freed all the tree,
|
||||
* so we need to correct eh_depth
|
||||
*/
|
||||
err = ext4_ext_get_access(handle, inode, path);
|
||||
if (err == 0) {
|
||||
|
|
@ -1912,7 +1940,7 @@ int ext4_ext_get_blocks(handle_t *handle, struct inode *inode,
|
|||
if (goal == EXT4_EXT_CACHE_GAP) {
|
||||
if (!create) {
|
||||
/* block isn't allocated yet and
|
||||
* user don't want to allocate it */
|
||||
* user doesn't want to allocate it */
|
||||
goto out2;
|
||||
}
|
||||
/* we should allocate requested block */
|
||||
|
|
@ -1921,7 +1949,7 @@ int ext4_ext_get_blocks(handle_t *handle, struct inode *inode,
|
|||
newblock = iblock
|
||||
- le32_to_cpu(newex.ee_block)
|
||||
+ ext_pblock(&newex);
|
||||
/* number of remain blocks in the extent */
|
||||
/* number of remaining blocks in the extent */
|
||||
allocated = le16_to_cpu(newex.ee_len) -
|
||||
(iblock - le32_to_cpu(newex.ee_block));
|
||||
goto out;
|
||||
|
|
@ -1941,8 +1969,8 @@ int ext4_ext_get_blocks(handle_t *handle, struct inode *inode,
|
|||
depth = ext_depth(inode);
|
||||
|
||||
/*
|
||||
* consistent leaf must not be empty
|
||||
* this situations is possible, though, _during_ tree modification
|
||||
* consistent leaf must not be empty;
|
||||
* this situation is possible, though, _during_ tree modification;
|
||||
* this is why assert can't be put in ext4_ext_find_extent()
|
||||
*/
|
||||
BUG_ON(path[depth].p_ext == NULL && depth != 0);
|
||||
|
|
@ -1960,10 +1988,10 @@ int ext4_ext_get_blocks(handle_t *handle, struct inode *inode,
|
|||
*/
|
||||
if (ee_len > EXT_MAX_LEN)
|
||||
goto out2;
|
||||
/* if found exent covers block, simple return it */
|
||||
/* if found extent covers block, simply return it */
|
||||
if (iblock >= ee_block && iblock < ee_block + ee_len) {
|
||||
newblock = iblock - ee_block + ee_start;
|
||||
/* number of remain blocks in the extent */
|
||||
/* number of remaining blocks in the extent */
|
||||
allocated = ee_len - (iblock - ee_block);
|
||||
ext_debug("%d fit into %lu:%d -> "E3FSBLK"\n", (int) iblock,
|
||||
ee_block, ee_len, newblock);
|
||||
|
|
@ -1974,17 +2002,18 @@ int ext4_ext_get_blocks(handle_t *handle, struct inode *inode,
|
|||
}
|
||||
|
||||
/*
|
||||
* requested block isn't allocated yet
|
||||
* requested block isn't allocated yet;
|
||||
* we couldn't try to create block if create flag is zero
|
||||
*/
|
||||
if (!create) {
|
||||
/* put just found gap into cache to speedup subsequest reqs */
|
||||
/* put just found gap into cache to speed up
|
||||
* subsequent requests */
|
||||
ext4_ext_put_gap_in_cache(inode, path, iblock);
|
||||
goto out2;
|
||||
}
|
||||
/*
|
||||
* Okay, we need to do block allocation. Lazily initialize the block
|
||||
* allocation info here if necessary
|
||||
* allocation info here if necessary.
|
||||
*/
|
||||
if (S_ISREG(inode->i_mode) && (!EXT4_I(inode)->i_block_alloc_info))
|
||||
ext4_init_block_alloc_info(inode);
|
||||
|
|
@ -2062,9 +2091,9 @@ void ext4_ext_truncate(struct inode * inode, struct page *page)
|
|||
ext4_ext_invalidate_cache(inode);
|
||||
|
||||
/*
|
||||
* TODO: optimization is possible here
|
||||
* probably we need not scaning at all,
|
||||
* because page truncation is enough
|
||||
* TODO: optimization is possible here.
|
||||
* Probably we need not scan at all,
|
||||
* because page truncation is enough.
|
||||
*/
|
||||
if (ext4_orphan_add(handle, inode))
|
||||
goto out_stop;
|
||||
|
|
@ -2078,13 +2107,13 @@ void ext4_ext_truncate(struct inode * inode, struct page *page)
|
|||
err = ext4_ext_remove_space(inode, last_block);
|
||||
|
||||
/* In a multi-transaction truncate, we only make the final
|
||||
* transaction synchronous */
|
||||
* transaction synchronous. */
|
||||
if (IS_SYNC(inode))
|
||||
handle->h_sync = 1;
|
||||
|
||||
out_stop:
|
||||
/*
|
||||
* If this was a simple ftruncate(), and the file will remain alive
|
||||
* If this was a simple ftruncate() and the file will remain alive,
|
||||
* then we need to clear up the orphan record which we created above.
|
||||
* However, if this was a real unlink then we were called by
|
||||
* ext4_delete_inode(), and we allow that function to clean up the
|
||||
|
|
@ -2098,7 +2127,8 @@ void ext4_ext_truncate(struct inode * inode, struct page *page)
|
|||
}
|
||||
|
||||
/*
|
||||
* this routine calculate max number of blocks we could modify
|
||||
* ext4_ext_writepage_trans_blocks:
|
||||
* calculate max number of blocks we could modify
|
||||
* in order to allocate new block for an inode
|
||||
*/
|
||||
int ext4_ext_writepage_trans_blocks(struct inode *inode, int num)
|
||||
|
|
@ -2107,7 +2137,7 @@ int ext4_ext_writepage_trans_blocks(struct inode *inode, int num)
|
|||
|
||||
needed = ext4_ext_calc_credits_for_insert(inode, NULL);
|
||||
|
||||
/* caller want to allocate num blocks, but note it includes sb */
|
||||
/* caller wants to allocate num blocks, but note it includes sb */
|
||||
needed = needed * num - (num - 1);
|
||||
|
||||
#ifdef CONFIG_QUOTA
|
||||
|
|
|
|||
|
|
@ -22,29 +22,29 @@
|
|||
#include <linux/ext4_fs.h>
|
||||
|
||||
/*
|
||||
* with AGRESSIVE_TEST defined capacity of index/leaf blocks
|
||||
* become very little, so index split, in-depth growing and
|
||||
* other hard changes happens much more often
|
||||
* this is for debug purposes only
|
||||
* With AGRESSIVE_TEST defined, the capacity of index/leaf blocks
|
||||
* becomes very small, so index split, in-depth growing and
|
||||
* other hard changes happen much more often.
|
||||
* This is for debug purposes only.
|
||||
*/
|
||||
#define AGRESSIVE_TEST_
|
||||
|
||||
/*
|
||||
* with EXTENTS_STATS defined number of blocks and extents
|
||||
* are collected in truncate path. they'll be showed at
|
||||
* umount time
|
||||
* With EXTENTS_STATS defined, the number of blocks and extents
|
||||
* are collected in the truncate path. They'll be shown at
|
||||
* umount time.
|
||||
*/
|
||||
#define EXTENTS_STATS__
|
||||
|
||||
/*
|
||||
* if CHECK_BINSEARCH defined, then results of binary search
|
||||
* will be checked by linear search
|
||||
* If CHECK_BINSEARCH is defined, then the results of the binary search
|
||||
* will also be checked by linear search.
|
||||
*/
|
||||
#define CHECK_BINSEARCH__
|
||||
|
||||
/*
|
||||
* if EXT_DEBUG is defined you can use 'extdebug' mount option
|
||||
* to get lots of info what's going on
|
||||
* If EXT_DEBUG is defined you can use the 'extdebug' mount option
|
||||
* to get lots of info about what's going on.
|
||||
*/
|
||||
#define EXT_DEBUG__
|
||||
#ifdef EXT_DEBUG
|
||||
|
|
@ -54,58 +54,58 @@
|
|||
#endif
|
||||
|
||||
/*
|
||||
* if EXT_STATS is defined then stats numbers are collected
|
||||
* these number will be displayed at umount time
|
||||
* If EXT_STATS is defined then stats numbers are collected.
|
||||
* These number will be displayed at umount time.
|
||||
*/
|
||||
#define EXT_STATS_
|
||||
|
||||
|
||||
/*
|
||||
* ext4_inode has i_block array (60 bytes total)
|
||||
* first 12 bytes store ext4_extent_header
|
||||
* the remain stores array of ext4_extent
|
||||
* ext4_inode has i_block array (60 bytes total).
|
||||
* The first 12 bytes store ext4_extent_header;
|
||||
* the remainder stores an array of ext4_extent.
|
||||
*/
|
||||
|
||||
/*
|
||||
* this is extent on-disk structure
|
||||
* it's used at the bottom of the tree
|
||||
* This is the extent on-disk structure.
|
||||
* It's used at the bottom of the tree.
|
||||
*/
|
||||
struct ext4_extent {
|
||||
__le32 ee_block; /* first logical block extent covers */
|
||||
__le16 ee_len; /* number of blocks covered by extent */
|
||||
__le16 ee_start_hi; /* high 16 bits of physical block */
|
||||
__le32 ee_start; /* low 32 bigs of physical block */
|
||||
__le32 ee_start; /* low 32 bits of physical block */
|
||||
};
|
||||
|
||||
/*
|
||||
* this is index on-disk structure
|
||||
* it's used at all the levels, but the bottom
|
||||
* This is index on-disk structure.
|
||||
* It's used at all the levels except the bottom.
|
||||
*/
|
||||
struct ext4_extent_idx {
|
||||
__le32 ei_block; /* index covers logical blocks from 'block' */
|
||||
__le32 ei_leaf; /* pointer to the physical block of the next *
|
||||
* level. leaf or next index could bet here */
|
||||
* level. leaf or next index could be there */
|
||||
__le16 ei_leaf_hi; /* high 16 bits of physical block */
|
||||
__u16 ei_unused;
|
||||
};
|
||||
|
||||
/*
|
||||
* each block (leaves and indexes), even inode-stored has header
|
||||
* Each block (leaves and indexes), even inode-stored has header.
|
||||
*/
|
||||
struct ext4_extent_header {
|
||||
__le16 eh_magic; /* probably will support different formats */
|
||||
__le16 eh_entries; /* number of valid entries */
|
||||
__le16 eh_max; /* capacity of store in entries */
|
||||
__le16 eh_depth; /* has tree real underlaying blocks? */
|
||||
__le16 eh_depth; /* has tree real underlying blocks? */
|
||||
__le32 eh_generation; /* generation of the tree */
|
||||
};
|
||||
|
||||
#define EXT4_EXT_MAGIC cpu_to_le16(0xf30a)
|
||||
|
||||
/*
|
||||
* array of ext4_ext_path contains path to some extent
|
||||
* creation/lookup routines use it for traversal/splitting/etc
|
||||
* truncate uses it to simulate recursive walking
|
||||
* Array of ext4_ext_path contains path to some extent.
|
||||
* Creation/lookup routines use it for traversal/splitting/etc.
|
||||
* Truncate uses it to simulate recursive walking.
|
||||
*/
|
||||
struct ext4_ext_path {
|
||||
ext4_fsblk_t p_block;
|
||||
|
|
|
|||
|
|
@ -28,8 +28,8 @@
|
|||
* indirection blocks, the group and superblock summaries, and the data
|
||||
* block to complete the transaction.
|
||||
*
|
||||
* For extents-enabled fs we may have to allocate and modify upto
|
||||
* 5 levels of tree + root which is stored in inode. */
|
||||
* For extents-enabled fs we may have to allocate and modify up to
|
||||
* 5 levels of tree + root which are stored in the inode. */
|
||||
|
||||
#define EXT4_SINGLEDATA_TRANS_BLOCKS(sb) \
|
||||
(EXT4_HAS_INCOMPAT_FEATURE(sb, EXT4_FEATURE_INCOMPAT_EXTENTS) \
|
||||
|
|
|
|||
Loading…
Reference in a new issue