xiaomi-sm8450/android_kernel_xiaomi_sm8450
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

nilfs2: add routines to roll back state of DAT file

Browse Source 
This adds optional function to metadata files which makes a copy of
bmap, page caches, and b-tree node cache, and rolls back to the copy
as needed.

This enhancement is intended to displace gcdat inode that provides a
similar function in a different way.

In this patch, nilfs_shadow_map structure is added to store a copy of
the foregoing states.  nilfs_mdt_setup_shadow_map relates this
structure to a metadata file.  And, nilfs_mdt_save_to_shadow_map() and
nilfs_mdt_restore_from_shadow_map() provides save and restore
functions respectively.  Finally, nilfs_mdt_clear_shadow_map() clears
states of nilfs_shadow_map.

The copy of b-tree node cache and page cache is made by duplicating
only dirty pages into corresponding caches in nilfs_shadow_map.  Their
restoration is done by clearing dirty pages from original caches and
by copying dirty pages back from nilfs_shadow_map.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
This commit is contained in:
Ryusuke Konishi
2010-09-06 12:05:43 +09:00
parent a8070dd365
commit ebdfed4dc5
5 changed files with 145 additions and 19 deletions
Download Patch File Download Diff File Expand all files Collapse all files

104
fs/nilfs2/mdt.c
View File

@@ -398,16 +398,22 @@ int nilfs_mdt_fetch_dirty(struct inode *inode)
static int
nilfs_mdt_write_page(struct page *page, struct writeback_control *wbc)
{
struct inode *inode = container_of(page->mapping,
struct inode, i_data);
struct super_block *sb = inode->i_sb;
struct the_nilfs *nilfs = NILFS_MDT(inode)->mi_nilfs;
struct inode *inode;
struct super_block *sb;
struct the_nilfs *nilfs;
struct nilfs_sb_info *writer = NULL;
int err = 0;
redirty_page_for_writepage(wbc, page);
unlock_page(page);
inode = page->mapping->host;
if (!inode)
return 0;
sb = inode->i_sb;
nilfs = NILFS_MDT(inode)->mi_nilfs;
if (page->mapping->assoc_mapping)
return 0; /* Do not request flush for shadow page cache */
if (!sb) {
@@ -567,6 +573,96 @@ void nilfs_mdt_set_shadow(struct inode *orig, struct inode *shadow)
&NILFS_I(orig)->i_btnode_cache;
}
static const struct address_space_operations shadow_map_aops = {
.sync_page = block_sync_page,
};
/**
* nilfs_mdt_setup_shadow_map - setup shadow map and bind it to metadata file
* @inode: inode of the metadata file
* @shadow: shadow mapping
*/
int nilfs_mdt_setup_shadow_map(struct inode *inode,
struct nilfs_shadow_map *shadow)
{
struct nilfs_mdt_info *mi = NILFS_MDT(inode);
struct backing_dev_info *bdi = NILFS_I_NILFS(inode)->ns_bdi;
INIT_LIST_HEAD(&shadow->frozen_buffers);
nilfs_mapping_init_once(&shadow->frozen_data);
nilfs_mapping_init(&shadow->frozen_data, bdi, &shadow_map_aops);
nilfs_mapping_init_once(&shadow->frozen_btnodes);
nilfs_mapping_init(&shadow->frozen_btnodes, bdi, &shadow_map_aops);
mi->mi_shadow = shadow;
return 0;
}
/**
* nilfs_mdt_save_to_shadow_map - copy bmap and dirty pages to shadow map
* @inode: inode of the metadata file
*/
int nilfs_mdt_save_to_shadow_map(struct inode *inode)
{
struct nilfs_mdt_info *mi = NILFS_MDT(inode);
struct nilfs_inode_info *ii = NILFS_I(inode);
struct nilfs_shadow_map *shadow = mi->mi_shadow;
int ret;
ret = nilfs_copy_dirty_pages(&shadow->frozen_data, inode->i_mapping);
if (ret)
goto out;
ret = nilfs_copy_dirty_pages(&shadow->frozen_btnodes,
&ii->i_btnode_cache);
if (ret)
goto out;
nilfs_bmap_save(ii->i_bmap, &shadow->bmap_store);
out:
return ret;
}
/**
* nilfs_mdt_restore_from_shadow_map - restore dirty pages and bmap state
* @inode: inode of the metadata file
*/
void nilfs_mdt_restore_from_shadow_map(struct inode *inode)
{
struct nilfs_mdt_info *mi = NILFS_MDT(inode);
struct nilfs_inode_info *ii = NILFS_I(inode);
struct nilfs_shadow_map *shadow = mi->mi_shadow;
down_write(&mi->mi_sem);
if (mi->mi_palloc_cache)
nilfs_palloc_clear_cache(inode);
nilfs_clear_dirty_pages(inode->i_mapping);
nilfs_copy_back_pages(inode->i_mapping, &shadow->frozen_data);
nilfs_clear_dirty_pages(&ii->i_btnode_cache);
nilfs_copy_back_pages(&ii->i_btnode_cache, &shadow->frozen_btnodes);
nilfs_bmap_restore(ii->i_bmap, &shadow->bmap_store);
up_write(&mi->mi_sem);
}
/**
* nilfs_mdt_clear_shadow_map - truncate pages in shadow map caches
* @inode: inode of the metadata file
*/
void nilfs_mdt_clear_shadow_map(struct inode *inode)
{
struct nilfs_mdt_info *mi = NILFS_MDT(inode);
struct nilfs_shadow_map *shadow = mi->mi_shadow;
down_write(&mi->mi_sem);
truncate_inode_pages(&shadow->frozen_data, 0);
truncate_inode_pages(&shadow->frozen_btnodes, 0);
up_write(&mi->mi_sem);
}
static void nilfs_mdt_clear(struct inode *inode)
{
struct nilfs_inode_info *ii = NILFS_I(inode);