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ocfs2: Abstract extent split process.
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ocfs2_mark_extent_written actually does the following things:
1. check the parameters.
2. initialize the left_path and split_rec.
3. call __ocfs2_mark_extent_written. it will do:
   1) check the flags of unwritten
   2) do the real split work.
The whole process is packed tightly somehow. So this patch
will abstract 2 different functions so that future b-tree
operation can work with it.

1. __ocfs2_split_extent will accept path and split_rec and do
  the real split work.
2. ocfs2_change_extent_flag will accept a new flag and initialize
   path and split_rec.

So now ocfs2_mark_extent_written will do:
1. check the parameters.
2. call ocfs2_change_extent_flag.
   1) initalize the left_path and split_rec.
   2) check whether the new flags conflict with the old one.
   3) call __ocfs2_split_extent to do the split.

Signed-off-by: Tao Ma <tao.ma@oracle.com>
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Tao Ma authored and Joel Becker committed Sep 23, 2009
1 parent 853a3a1 commit 555936b
Showing 1 changed file with 100 additions and 50 deletions.
150 changes: 100 additions & 50 deletions fs/ocfs2/alloc.c
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Original file line number Diff line number Diff line change
Expand Up @@ -5032,9 +5032,8 @@ static int ocfs2_replace_extent_rec(handle_t *handle,
}

/*
* Mark part or all of the extent record at split_index in the leaf
* pointed to by path as written. This removes the unwritten
* extent flag.
* Split part or all of the extent record at split_index in the leaf
* pointed to by path. Merge with the contiguous extent record if needed.
*
* Care is taken to handle contiguousness so as to not grow the tree.
*
Expand All @@ -5051,13 +5050,13 @@ static int ocfs2_replace_extent_rec(handle_t *handle,
* have been brought into cache (and pinned via the journal), so the
* extra overhead is not expressed in terms of disk reads.
*/
static int __ocfs2_mark_extent_written(handle_t *handle,
struct ocfs2_extent_tree *et,
struct ocfs2_path *path,
int split_index,
struct ocfs2_extent_rec *split_rec,
struct ocfs2_alloc_context *meta_ac,
struct ocfs2_cached_dealloc_ctxt *dealloc)
static int __ocfs2_split_extent(handle_t *handle,
struct ocfs2_extent_tree *et,
struct ocfs2_path *path,
int split_index,
struct ocfs2_extent_rec *split_rec,
struct ocfs2_alloc_context *meta_ac,
struct ocfs2_cached_dealloc_ctxt *dealloc)
{
int ret = 0;
struct ocfs2_extent_list *el = path_leaf_el(path);
Expand All @@ -5066,12 +5065,6 @@ static int __ocfs2_mark_extent_written(handle_t *handle,
struct ocfs2_merge_ctxt ctxt;
struct ocfs2_extent_list *rightmost_el;

if (!(rec->e_flags & OCFS2_EXT_UNWRITTEN)) {
ret = -EIO;
mlog_errno(ret);
goto out;
}

if (le32_to_cpu(rec->e_cpos) > le32_to_cpu(split_rec->e_cpos) ||
((le32_to_cpu(rec->e_cpos) + le16_to_cpu(rec->e_leaf_clusters)) <
(le32_to_cpu(split_rec->e_cpos) + le16_to_cpu(split_rec->e_leaf_clusters)))) {
Expand Down Expand Up @@ -5141,42 +5134,31 @@ static int __ocfs2_mark_extent_written(handle_t *handle,
}

/*
* Mark the already-existing extent at cpos as written for len clusters.
* Change the flags of the already-existing extent at cpos for len clusters.
*
* new_flags: the flags we want to set.
* clear_flags: the flags we want to clear.
* phys: the new physical offset we want this new extent starts from.
*
* If the existing extent is larger than the request, initiate a
* split. An attempt will be made at merging with adjacent extents.
*
* The caller is responsible for passing down meta_ac if we'll need it.
*/
int ocfs2_mark_extent_written(struct inode *inode,
struct ocfs2_extent_tree *et,
handle_t *handle, u32 cpos, u32 len, u32 phys,
struct ocfs2_alloc_context *meta_ac,
struct ocfs2_cached_dealloc_ctxt *dealloc)
static int ocfs2_change_extent_flag(handle_t *handle,
struct ocfs2_extent_tree *et,
u32 cpos, u32 len, u32 phys,
struct ocfs2_alloc_context *meta_ac,
struct ocfs2_cached_dealloc_ctxt *dealloc,
int new_flags, int clear_flags)
{
int ret, index;
u64 start_blkno = ocfs2_clusters_to_blocks(inode->i_sb, phys);
struct super_block *sb = ocfs2_metadata_cache_get_super(et->et_ci);
u64 start_blkno = ocfs2_clusters_to_blocks(sb, phys);
struct ocfs2_extent_rec split_rec;
struct ocfs2_path *left_path = NULL;
struct ocfs2_extent_list *el;

mlog(0, "Inode %lu cpos %u, len %u, phys %u (%llu)\n",
inode->i_ino, cpos, len, phys, (unsigned long long)start_blkno);

if (!ocfs2_writes_unwritten_extents(OCFS2_SB(inode->i_sb))) {
ocfs2_error(inode->i_sb, "Inode %llu has unwritten extents "
"that are being written to, but the feature bit "
"is not set in the super block.",
(unsigned long long)OCFS2_I(inode)->ip_blkno);
ret = -EROFS;
goto out;
}

/*
* XXX: This should be fixed up so that we just re-insert the
* next extent records.
*/
ocfs2_et_extent_map_truncate(et, 0);
struct ocfs2_extent_rec *rec;

left_path = ocfs2_new_path_from_et(et);
if (!left_path) {
Expand All @@ -5194,30 +5176,98 @@ int ocfs2_mark_extent_written(struct inode *inode,

index = ocfs2_search_extent_list(el, cpos);
if (index == -1 || index >= le16_to_cpu(el->l_next_free_rec)) {
ocfs2_error(inode->i_sb,
"Inode %llu has an extent at cpos %u which can no "
ocfs2_error(sb,
"Owner %llu has an extent at cpos %u which can no "
"longer be found.\n",
(unsigned long long)OCFS2_I(inode)->ip_blkno, cpos);
(unsigned long long)
ocfs2_metadata_cache_owner(et->et_ci), cpos);
ret = -EROFS;
goto out;
}

ret = -EIO;
rec = &el->l_recs[index];
if (new_flags && (rec->e_flags & new_flags)) {
mlog(ML_ERROR, "Owner %llu tried to set %d flags on an "
"extent that already had them",
(unsigned long long)ocfs2_metadata_cache_owner(et->et_ci),
new_flags);
goto out;
}

if (clear_flags && !(rec->e_flags & clear_flags)) {
mlog(ML_ERROR, "Owner %llu tried to clear %d flags on an "
"extent that didn't have them",
(unsigned long long)ocfs2_metadata_cache_owner(et->et_ci),
clear_flags);
goto out;
}

memset(&split_rec, 0, sizeof(struct ocfs2_extent_rec));
split_rec.e_cpos = cpu_to_le32(cpos);
split_rec.e_leaf_clusters = cpu_to_le16(len);
split_rec.e_blkno = cpu_to_le64(start_blkno);
split_rec.e_flags = path_leaf_el(left_path)->l_recs[index].e_flags;
split_rec.e_flags &= ~OCFS2_EXT_UNWRITTEN;

ret = __ocfs2_mark_extent_written(handle, et, left_path,
index, &split_rec, meta_ac,
dealloc);
split_rec.e_flags = rec->e_flags;
if (new_flags)
split_rec.e_flags |= new_flags;
if (clear_flags)
split_rec.e_flags &= ~clear_flags;

ret = __ocfs2_split_extent(handle, et, left_path,
index, &split_rec, meta_ac,
dealloc);
if (ret)
mlog_errno(ret);

out:
ocfs2_free_path(left_path);
return ret;

}

/*
* Mark the already-existing extent at cpos as written for len clusters.
* This removes the unwritten extent flag.
*
* If the existing extent is larger than the request, initiate a
* split. An attempt will be made at merging with adjacent extents.
*
* The caller is responsible for passing down meta_ac if we'll need it.
*/
int ocfs2_mark_extent_written(struct inode *inode,
struct ocfs2_extent_tree *et,
handle_t *handle, u32 cpos, u32 len, u32 phys,
struct ocfs2_alloc_context *meta_ac,
struct ocfs2_cached_dealloc_ctxt *dealloc)
{
int ret;

mlog(0, "Inode %lu cpos %u, len %u, phys clusters %u\n",
inode->i_ino, cpos, len, phys);

if (!ocfs2_writes_unwritten_extents(OCFS2_SB(inode->i_sb))) {
ocfs2_error(inode->i_sb, "Inode %llu has unwritten extents "
"that are being written to, but the feature bit "
"is not set in the super block.",
(unsigned long long)OCFS2_I(inode)->ip_blkno);
ret = -EROFS;
goto out;
}

/*
* XXX: This should be fixed up so that we just re-insert the
* next extent records.
*/
ocfs2_et_extent_map_truncate(et, 0);

ret = ocfs2_change_extent_flag(handle, et, cpos,
len, phys, meta_ac, dealloc,
0, OCFS2_EXT_UNWRITTEN);
if (ret)
mlog_errno(ret);

out:
return ret;
}

static int ocfs2_split_tree(handle_t *handle, struct ocfs2_extent_tree *et,
Expand Down

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