/* * 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 super_block *sb = inode->i_sb; struct nilfs_transaction_info ti; struct buffer_head *bh; int err; if (!sb) { /* * Make sure this function is not called from any * read-only context. */ if (!nilfs->ns_writer) { WARN_ON(1); err = -EROFS; goto out; } sb = nilfs->ns_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)) goto failed_bh; wait_on_buffer(bh); if (buffer_uptodate(bh)) goto failed_bh; 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); 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; __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; } bh->b_bdev = NILFS_MDT(inode)->mi_nilfs->ns_bdev; bh->b_blocknr = (sector_t)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 (!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) * * %-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 the_nilfs *nilfs = NILFS_MDT(inode)->mi_nilfs; 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) { down_read(&nilfs->ns_writer_sem); writer = nilfs->ns_writer; if (!writer) { up_read(&nilfs->ns_writer_sem); 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) up_read(&nilfs->ns_writer_sem); return err; } static const struct address_space_operations def_mdt_aops = { .writepage = nilfs_mdt_write_page, .sync_page = block_sync_page, }; static const struct inode_operations def_mdt_iops; static const 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_common(nilfs); 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) { struct inode *inode = nilfs_mdt_new_common(nilfs, sb, ino, NILFS_MDT_GFP); 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); }