diff options
Diffstat (limited to 'fs/nilfs2/mdt.c')
| -rw-r--r-- | fs/nilfs2/mdt.c | 563 |
1 files changed, 563 insertions, 0 deletions
diff --git a/fs/nilfs2/mdt.c b/fs/nilfs2/mdt.c new file mode 100644 index 0000000..47dd8154 --- /dev/null +++ b/fs/nilfs2/mdt.c @@ -0,0 +1,563 @@ +/* + * 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 "nilfs.h" +#include "segment.h" +#include "page.h" +#include "mdt.h" + + +#define NILFS_MDT_MAX_RA_BLOCKS (16 - 1) + +#define INIT_UNUSED_INODE_FIELDS + +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, KM_USER0); + 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, KM_USER0); + + set_buffer_uptodate(bh); + nilfs_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 the_nilfs *nilfs = NILFS_MDT(inode)->mi_nilfs; + struct nilfs_sb_info *writer = NULL; + struct super_block *sb = inode->i_sb; + struct nilfs_transaction_info ti; + struct buffer_head *bh; + int err; + + if (!sb) { + writer = nilfs_get_writer(nilfs); + if (!writer) { + err = -EROFS; + goto out; + } + sb = writer->s_super; + } + + 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) || buffer_mapped(bh)) + goto failed_bh; +#if 0 + /* The uptodate flag is not protected by the page lock, but + the mapped flag is. Thus, we don't have to wait the buffer. */ + wait_on_buffer(bh); + if (buffer_uptodate(bh)) + goto failed_bh; +#endif + + bh->b_bdev = nilfs->ns_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); + if (writer) + nilfs_put_writer(nilfs); + out: + 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; + unsigned long 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; + } + if (!buffer_mapped(bh)) { /* unused buffer */ + ret = nilfs_bmap_lookup(NILFS_I(inode)->i_bmap, blkoff, + &blknum); + if (unlikely(ret)) { + unlock_buffer(bh); + goto failed_bh; + } + bh->b_bdev = NILFS_MDT(inode)->mi_nilfs->ns_bdev; + bh->b_blocknr = blknum; + set_buffer_mapped(bh); + } + + 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, + 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; + + 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) + * + * %-EINVAL - bmap is broken. (the caller should call nilfs_error()) + * + * %-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, 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_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 + * + * %-EINVAL - bmap is broken. (the caller should call nilfs_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 (likely(!err)) { + 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) + * + * %-EINVAL - bmap is broken. (the caller should call nilfs_error()) + */ +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, &bh); + if (unlikely(err)) + return err; + nilfs_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 = container_of(page->mapping, + struct inode, i_data); + struct super_block *sb = inode->i_sb; + struct nilfs_sb_info *writer = NULL; + int err = 0; + + redirty_page_for_writepage(wbc, page); + unlock_page(page); + + if (page->mapping->assoc_mapping) + return 0; /* Do not request flush for shadow page cache */ + if (!sb) { + writer = nilfs_get_writer(NILFS_MDT(inode)->mi_nilfs); + if (!writer) + return -EROFS; + sb = writer->s_super; + } + + if (wbc->sync_mode == WB_SYNC_ALL) + err = nilfs_construct_segment(sb); + else if (wbc->for_reclaim) + nilfs_flush_segment(sb, inode->i_ino); + + if (writer) + nilfs_put_writer(NILFS_MDT(inode)->mi_nilfs); + return err; +} + + +static struct address_space_operations def_mdt_aops = { + .writepage = nilfs_mdt_write_page, +}; + +static struct inode_operations def_mdt_iops; +static struct file_operations def_mdt_fops; + +/* + * NILFS2 uses pseudo inodes for meta data files such as DAT, cpfile, sufile, + * ifile, or gcinodes. This allows the B-tree code and segment constructor + * to treat them like regular files, and this helps to simplify the + * implementation. + * On the other hand, some of the pseudo inodes have an irregular point: + * They don't have valid inode->i_sb pointer because their lifetimes are + * longer than those of the super block structs; they may continue for + * several consecutive mounts/umounts. This would need discussions. + */ +struct inode * +nilfs_mdt_new_common(struct the_nilfs *nilfs, struct super_block *sb, + ino_t ino, gfp_t gfp_mask) +{ + struct inode *inode = nilfs_alloc_inode(sb); + + if (!inode) + return NULL; + else { + struct address_space * const mapping = &inode->i_data; + struct nilfs_mdt_info *mi = kzalloc(sizeof(*mi), GFP_NOFS); + + if (!mi) { + nilfs_destroy_inode(inode); + return NULL; + } + mi->mi_nilfs = nilfs; + init_rwsem(&mi->mi_sem); + + inode->i_sb = sb; /* sb may be NULL for some meta data files */ + inode->i_blkbits = nilfs->ns_blocksize_bits; + inode->i_flags = 0; + atomic_set(&inode->i_count, 1); + inode->i_nlink = 1; + inode->i_ino = ino; + inode->i_mode = S_IFREG; + inode->i_private = mi; + +#ifdef INIT_UNUSED_INODE_FIELDS + atomic_set(&inode->i_writecount, 0); + inode->i_size = 0; + inode->i_blocks = 0; + inode->i_bytes = 0; + inode->i_generation = 0; +#ifdef CONFIG_QUOTA + memset(&inode->i_dquot, 0, sizeof(inode->i_dquot)); +#endif + inode->i_pipe = NULL; + inode->i_bdev = NULL; + inode->i_cdev = NULL; + inode->i_rdev = 0; +#ifdef CONFIG_SECURITY + inode->i_security = NULL; +#endif + inode->dirtied_when = 0; + + INIT_LIST_HEAD(&inode->i_list); + INIT_LIST_HEAD(&inode->i_sb_list); + inode->i_state = 0; +#endif + + spin_lock_init(&inode->i_lock); + mutex_init(&inode->i_mutex); + init_rwsem(&inode->i_alloc_sem); + + mapping->host = NULL; /* instead of inode */ + mapping->flags = 0; + mapping_set_gfp_mask(mapping, gfp_mask); + mapping->assoc_mapping = NULL; + mapping->backing_dev_info = nilfs->ns_bdi; + + inode->i_mapping = mapping; + } + + return inode; +} + +struct inode *nilfs_mdt_new(struct the_nilfs *nilfs, struct super_block *sb, + ino_t ino, gfp_t gfp_mask) +{ + struct inode *inode = nilfs_mdt_new_common(nilfs, sb, ino, gfp_mask); + + if (!inode) + return NULL; + + inode->i_op = &def_mdt_iops; + inode->i_fop = &def_mdt_fops; + inode->i_mapping->a_ops = &def_mdt_aops; + return inode; +} + +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); +} + +void nilfs_mdt_set_shadow(struct inode *orig, struct inode *shadow) +{ + shadow->i_mapping->assoc_mapping = orig->i_mapping; + NILFS_I(shadow)->i_btnode_cache.assoc_mapping = + &NILFS_I(orig)->i_btnode_cache; +} + +void nilfs_mdt_clear(struct inode *inode) +{ + struct nilfs_inode_info *ii = NILFS_I(inode); + + invalidate_mapping_pages(inode->i_mapping, 0, -1); + truncate_inode_pages(inode->i_mapping, 0); + + nilfs_bmap_clear(ii->i_bmap); + nilfs_btnode_cache_clear(&ii->i_btnode_cache); +} + +void nilfs_mdt_destroy(struct inode *inode) +{ + struct nilfs_mdt_info *mdi = NILFS_MDT(inode); + + kfree(mdi->mi_bgl); /* kfree(NULL) is safe */ + kfree(mdi); + nilfs_destroy_inode(inode); +} |