diff options
Diffstat (limited to 'kernel/fs/nilfs2/mdt.c')
| -rw-r--r-- | kernel/fs/nilfs2/mdt.c | 652 |
1 files changed, 652 insertions, 0 deletions
diff --git a/kernel/fs/nilfs2/mdt.c b/kernel/fs/nilfs2/mdt.c new file mode 100644 index 000000000..dee34d990 --- /dev/null +++ b/kernel/fs/nilfs2/mdt.c @@ -0,0 +1,652 @@ +/* + * mdt.c - meta data file for NILFS + * + * Copyright (C) 2005-2008 Nippon Telegraph and Telephone Corporation. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA + * + * Written by Ryusuke Konishi <ryusuke@osrg.net> + */ + +#include <linux/buffer_head.h> +#include <linux/mpage.h> +#include <linux/mm.h> +#include <linux/writeback.h> +#include <linux/backing-dev.h> +#include <linux/swap.h> +#include <linux/slab.h> +#include "nilfs.h" +#include "btnode.h" +#include "segment.h" +#include "page.h" +#include "mdt.h" + + +#define NILFS_MDT_MAX_RA_BLOCKS (16 - 1) + + +static int +nilfs_mdt_insert_new_block(struct inode *inode, unsigned long block, + struct buffer_head *bh, + void (*init_block)(struct inode *, + struct buffer_head *, void *)) +{ + struct nilfs_inode_info *ii = NILFS_I(inode); + void *kaddr; + int ret; + + /* Caller exclude read accesses using page lock */ + + /* set_buffer_new(bh); */ + bh->b_blocknr = 0; + + ret = nilfs_bmap_insert(ii->i_bmap, block, (unsigned long)bh); + if (unlikely(ret)) + return ret; + + set_buffer_mapped(bh); + + kaddr = kmap_atomic(bh->b_page); + memset(kaddr + bh_offset(bh), 0, 1 << inode->i_blkbits); + if (init_block) + init_block(inode, bh, kaddr); + flush_dcache_page(bh->b_page); + kunmap_atomic(kaddr); + + set_buffer_uptodate(bh); + mark_buffer_dirty(bh); + nilfs_mdt_mark_dirty(inode); + return 0; +} + +static int nilfs_mdt_create_block(struct inode *inode, unsigned long block, + struct buffer_head **out_bh, + void (*init_block)(struct inode *, + struct buffer_head *, + void *)) +{ + struct super_block *sb = inode->i_sb; + struct nilfs_transaction_info ti; + struct buffer_head *bh; + int err; + + nilfs_transaction_begin(sb, &ti, 0); + + err = -ENOMEM; + bh = nilfs_grab_buffer(inode, inode->i_mapping, block, 0); + if (unlikely(!bh)) + goto failed_unlock; + + err = -EEXIST; + if (buffer_uptodate(bh)) + goto failed_bh; + + wait_on_buffer(bh); + if (buffer_uptodate(bh)) + goto failed_bh; + + bh->b_bdev = sb->s_bdev; + err = nilfs_mdt_insert_new_block(inode, block, bh, init_block); + if (likely(!err)) { + get_bh(bh); + *out_bh = bh; + } + + failed_bh: + unlock_page(bh->b_page); + page_cache_release(bh->b_page); + brelse(bh); + + failed_unlock: + if (likely(!err)) + err = nilfs_transaction_commit(sb); + else + nilfs_transaction_abort(sb); + + return err; +} + +static int +nilfs_mdt_submit_block(struct inode *inode, unsigned long blkoff, + int mode, struct buffer_head **out_bh) +{ + struct buffer_head *bh; + __u64 blknum = 0; + int ret = -ENOMEM; + + bh = nilfs_grab_buffer(inode, inode->i_mapping, blkoff, 0); + if (unlikely(!bh)) + goto failed; + + ret = -EEXIST; /* internal code */ + if (buffer_uptodate(bh)) + goto out; + + if (mode == READA) { + if (!trylock_buffer(bh)) { + ret = -EBUSY; + goto failed_bh; + } + } else /* mode == READ */ + lock_buffer(bh); + + if (buffer_uptodate(bh)) { + unlock_buffer(bh); + goto out; + } + + ret = nilfs_bmap_lookup(NILFS_I(inode)->i_bmap, blkoff, &blknum); + if (unlikely(ret)) { + unlock_buffer(bh); + goto failed_bh; + } + map_bh(bh, inode->i_sb, (sector_t)blknum); + + bh->b_end_io = end_buffer_read_sync; + get_bh(bh); + submit_bh(mode, bh); + ret = 0; + out: + get_bh(bh); + *out_bh = bh; + + failed_bh: + unlock_page(bh->b_page); + page_cache_release(bh->b_page); + brelse(bh); + failed: + return ret; +} + +static int nilfs_mdt_read_block(struct inode *inode, unsigned long block, + int readahead, struct buffer_head **out_bh) +{ + struct buffer_head *first_bh, *bh; + unsigned long blkoff; + int i, nr_ra_blocks = NILFS_MDT_MAX_RA_BLOCKS; + int err; + + err = nilfs_mdt_submit_block(inode, block, READ, &first_bh); + if (err == -EEXIST) /* internal code */ + goto out; + + if (unlikely(err)) + goto failed; + + if (readahead) { + blkoff = block + 1; + for (i = 0; i < nr_ra_blocks; i++, blkoff++) { + err = nilfs_mdt_submit_block(inode, blkoff, READA, &bh); + if (likely(!err || err == -EEXIST)) + brelse(bh); + else if (err != -EBUSY) + break; + /* abort readahead if bmap lookup failed */ + if (!buffer_locked(first_bh)) + goto out_no_wait; + } + } + + wait_on_buffer(first_bh); + + out_no_wait: + err = -EIO; + if (!buffer_uptodate(first_bh)) + goto failed_bh; + out: + *out_bh = first_bh; + return 0; + + failed_bh: + brelse(first_bh); + failed: + return err; +} + +/** + * nilfs_mdt_get_block - read or create a buffer on meta data file. + * @inode: inode of the meta data file + * @blkoff: block offset + * @create: create flag + * @init_block: initializer used for newly allocated block + * @out_bh: output of a pointer to the buffer_head + * + * nilfs_mdt_get_block() looks up the specified buffer and tries to create + * a new buffer if @create is not zero. On success, the returned buffer is + * assured to be either existing or formatted using a buffer lock on success. + * @out_bh is substituted only when zero is returned. + * + * Return Value: On success, it returns 0. On error, the following negative + * error code is returned. + * + * %-ENOMEM - Insufficient memory available. + * + * %-EIO - I/O error + * + * %-ENOENT - the specified block does not exist (hole block) + * + * %-EROFS - Read only filesystem (for create mode) + */ +int nilfs_mdt_get_block(struct inode *inode, unsigned long blkoff, int create, + void (*init_block)(struct inode *, + struct buffer_head *, void *), + struct buffer_head **out_bh) +{ + int ret; + + /* Should be rewritten with merging nilfs_mdt_read_block() */ + retry: + ret = nilfs_mdt_read_block(inode, blkoff, !create, out_bh); + if (!create || ret != -ENOENT) + return ret; + + ret = nilfs_mdt_create_block(inode, blkoff, out_bh, init_block); + if (unlikely(ret == -EEXIST)) { + /* create = 0; */ /* limit read-create loop retries */ + goto retry; + } + return ret; +} + +/** + * nilfs_mdt_find_block - find and get a buffer on meta data file. + * @inode: inode of the meta data file + * @start: start block offset (inclusive) + * @end: end block offset (inclusive) + * @blkoff: block offset + * @out_bh: place to store a pointer to buffer_head struct + * + * nilfs_mdt_find_block() looks up an existing block in range of + * [@start, @end] and stores pointer to a buffer head of the block to + * @out_bh, and block offset to @blkoff, respectively. @out_bh and + * @blkoff are substituted only when zero is returned. + * + * Return Value: On success, it returns 0. On error, the following negative + * error code is returned. + * + * %-ENOMEM - Insufficient memory available. + * + * %-EIO - I/O error + * + * %-ENOENT - no block was found in the range + */ +int nilfs_mdt_find_block(struct inode *inode, unsigned long start, + unsigned long end, unsigned long *blkoff, + struct buffer_head **out_bh) +{ + __u64 next; + int ret; + + if (unlikely(start > end)) + return -ENOENT; + + ret = nilfs_mdt_read_block(inode, start, true, out_bh); + if (!ret) { + *blkoff = start; + goto out; + } + if (unlikely(ret != -ENOENT || start == ULONG_MAX)) + goto out; + + ret = nilfs_bmap_seek_key(NILFS_I(inode)->i_bmap, start + 1, &next); + if (!ret) { + if (next <= end) { + ret = nilfs_mdt_read_block(inode, next, true, out_bh); + if (!ret) + *blkoff = next; + } else { + ret = -ENOENT; + } + } +out: + return ret; +} + +/** + * nilfs_mdt_delete_block - make a hole on the meta data file. + * @inode: inode of the meta data file + * @block: block offset + * + * Return Value: On success, zero is returned. + * On error, one of the following negative error code is returned. + * + * %-ENOMEM - Insufficient memory available. + * + * %-EIO - I/O error + */ +int nilfs_mdt_delete_block(struct inode *inode, unsigned long block) +{ + struct nilfs_inode_info *ii = NILFS_I(inode); + int err; + + err = nilfs_bmap_delete(ii->i_bmap, block); + if (!err || err == -ENOENT) { + nilfs_mdt_mark_dirty(inode); + nilfs_mdt_forget_block(inode, block); + } + return err; +} + +/** + * nilfs_mdt_forget_block - discard dirty state and try to remove the page + * @inode: inode of the meta data file + * @block: block offset + * + * nilfs_mdt_forget_block() clears a dirty flag of the specified buffer, and + * tries to release the page including the buffer from a page cache. + * + * Return Value: On success, 0 is returned. On error, one of the following + * negative error code is returned. + * + * %-EBUSY - page has an active buffer. + * + * %-ENOENT - page cache has no page addressed by the offset. + */ +int nilfs_mdt_forget_block(struct inode *inode, unsigned long block) +{ + pgoff_t index = (pgoff_t)block >> + (PAGE_CACHE_SHIFT - inode->i_blkbits); + struct page *page; + unsigned long first_block; + int ret = 0; + int still_dirty; + + page = find_lock_page(inode->i_mapping, index); + if (!page) + return -ENOENT; + + wait_on_page_writeback(page); + + first_block = (unsigned long)index << + (PAGE_CACHE_SHIFT - inode->i_blkbits); + if (page_has_buffers(page)) { + struct buffer_head *bh; + + bh = nilfs_page_get_nth_block(page, block - first_block); + nilfs_forget_buffer(bh); + } + still_dirty = PageDirty(page); + unlock_page(page); + page_cache_release(page); + + if (still_dirty || + invalidate_inode_pages2_range(inode->i_mapping, index, index) != 0) + ret = -EBUSY; + return ret; +} + +/** + * nilfs_mdt_mark_block_dirty - mark a block on the meta data file dirty. + * @inode: inode of the meta data file + * @block: block offset + * + * Return Value: On success, it returns 0. On error, the following negative + * error code is returned. + * + * %-ENOMEM - Insufficient memory available. + * + * %-EIO - I/O error + * + * %-ENOENT - the specified block does not exist (hole block) + */ +int nilfs_mdt_mark_block_dirty(struct inode *inode, unsigned long block) +{ + struct buffer_head *bh; + int err; + + err = nilfs_mdt_read_block(inode, block, 0, &bh); + if (unlikely(err)) + return err; + mark_buffer_dirty(bh); + nilfs_mdt_mark_dirty(inode); + brelse(bh); + return 0; +} + +int nilfs_mdt_fetch_dirty(struct inode *inode) +{ + struct nilfs_inode_info *ii = NILFS_I(inode); + + if (nilfs_bmap_test_and_clear_dirty(ii->i_bmap)) { + set_bit(NILFS_I_DIRTY, &ii->i_state); + return 1; + } + return test_bit(NILFS_I_DIRTY, &ii->i_state); +} + +static int +nilfs_mdt_write_page(struct page *page, struct writeback_control *wbc) +{ + struct inode *inode = page->mapping->host; + struct super_block *sb; + int err = 0; + + if (inode && (inode->i_sb->s_flags & MS_RDONLY)) { + /* + * It means that filesystem was remounted in read-only + * mode because of error or metadata corruption. But we + * have dirty pages that try to be flushed in background. + * So, here we simply discard this dirty page. + */ + nilfs_clear_dirty_page(page, false); + unlock_page(page); + return -EROFS; + } + + redirty_page_for_writepage(wbc, page); + unlock_page(page); + + if (!inode) + return 0; + + sb = inode->i_sb; + + if (wbc->sync_mode == WB_SYNC_ALL) + err = nilfs_construct_segment(sb); + else if (wbc->for_reclaim) + nilfs_flush_segment(sb, inode->i_ino); + + return err; +} + + +static const struct address_space_operations def_mdt_aops = { + .writepage = nilfs_mdt_write_page, +}; + +static const struct inode_operations def_mdt_iops; +static const struct file_operations def_mdt_fops; + + +int nilfs_mdt_init(struct inode *inode, gfp_t gfp_mask, size_t objsz) +{ + struct nilfs_mdt_info *mi; + + mi = kzalloc(max(sizeof(*mi), objsz), GFP_NOFS); + if (!mi) + return -ENOMEM; + + init_rwsem(&mi->mi_sem); + inode->i_private = mi; + + inode->i_mode = S_IFREG; + mapping_set_gfp_mask(inode->i_mapping, gfp_mask); + + inode->i_op = &def_mdt_iops; + inode->i_fop = &def_mdt_fops; + inode->i_mapping->a_ops = &def_mdt_aops; + + return 0; +} + +void nilfs_mdt_set_entry_size(struct inode *inode, unsigned entry_size, + unsigned header_size) +{ + struct nilfs_mdt_info *mi = NILFS_MDT(inode); + + mi->mi_entry_size = entry_size; + mi->mi_entries_per_block = (1 << inode->i_blkbits) / entry_size; + mi->mi_first_entry_offset = DIV_ROUND_UP(header_size, entry_size); +} + +/** + * 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); + + INIT_LIST_HEAD(&shadow->frozen_buffers); + address_space_init_once(&shadow->frozen_data); + nilfs_mapping_init(&shadow->frozen_data, inode); + address_space_init_once(&shadow->frozen_btnodes); + nilfs_mapping_init(&shadow->frozen_btnodes, inode); + 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; +} + +int nilfs_mdt_freeze_buffer(struct inode *inode, struct buffer_head *bh) +{ + struct nilfs_shadow_map *shadow = NILFS_MDT(inode)->mi_shadow; + struct buffer_head *bh_frozen; + struct page *page; + int blkbits = inode->i_blkbits; + + page = grab_cache_page(&shadow->frozen_data, bh->b_page->index); + if (!page) + return -ENOMEM; + + if (!page_has_buffers(page)) + create_empty_buffers(page, 1 << blkbits, 0); + + bh_frozen = nilfs_page_get_nth_block(page, bh_offset(bh) >> blkbits); + + if (!buffer_uptodate(bh_frozen)) + nilfs_copy_buffer(bh_frozen, bh); + if (list_empty(&bh_frozen->b_assoc_buffers)) { + list_add_tail(&bh_frozen->b_assoc_buffers, + &shadow->frozen_buffers); + set_buffer_nilfs_redirected(bh); + } else { + brelse(bh_frozen); /* already frozen */ + } + + unlock_page(page); + page_cache_release(page); + return 0; +} + +struct buffer_head * +nilfs_mdt_get_frozen_buffer(struct inode *inode, struct buffer_head *bh) +{ + struct nilfs_shadow_map *shadow = NILFS_MDT(inode)->mi_shadow; + struct buffer_head *bh_frozen = NULL; + struct page *page; + int n; + + page = find_lock_page(&shadow->frozen_data, bh->b_page->index); + if (page) { + if (page_has_buffers(page)) { + n = bh_offset(bh) >> inode->i_blkbits; + bh_frozen = nilfs_page_get_nth_block(page, n); + } + unlock_page(page); + page_cache_release(page); + } + return bh_frozen; +} + +static void nilfs_release_frozen_buffers(struct nilfs_shadow_map *shadow) +{ + struct list_head *head = &shadow->frozen_buffers; + struct buffer_head *bh; + + while (!list_empty(head)) { + bh = list_first_entry(head, struct buffer_head, + b_assoc_buffers); + list_del_init(&bh->b_assoc_buffers); + brelse(bh); /* drop ref-count to make it releasable */ + } +} + +/** + * 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, true); + nilfs_copy_back_pages(inode->i_mapping, &shadow->frozen_data); + + nilfs_clear_dirty_pages(&ii->i_btnode_cache, true); + 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); + nilfs_release_frozen_buffers(shadow); + truncate_inode_pages(&shadow->frozen_data, 0); + truncate_inode_pages(&shadow->frozen_btnodes, 0); + up_write(&mi->mi_sem); +} |