nilfs2: inode operations

/*

 * inode.c - NILFS inode operations.

 *

 * 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/writeback.h>

#include "nilfs.h"

#include "segment.h"

#include "page.h"

#include "mdt.h"

#include "cpfile.h"

#include "ifile.h"

/**

 * nilfs_get_block() - get a file block on the filesystem (callback function)

 * @inode - inode struct of the target file

 * @blkoff - file block number

 * @bh_result - buffer head to be mapped on

 * @create - indicate whether allocating the block or not when it has not

 *      been allocated yet.

 *

 * This function does not issue actual read request of the specified data

 * block. It is done by VFS.

 * Bulk read for direct-io is not supported yet. (should be supported)

 */

int nilfs_get_block(struct inode *inode, sector_t blkoff,

		    struct buffer_head *bh_result, int create)

{

	struct nilfs_inode_info *ii = NILFS_I(inode);

	unsigned long blknum = 0;

	int err = 0, ret;

	struct inode *dat = nilfs_dat_inode(NILFS_I_NILFS(inode));

	/* This exclusion control is a workaround; should be revised */

	down_read(&NILFS_MDT(dat)->mi_sem);	/* XXX */

	ret = nilfs_bmap_lookup(ii->i_bmap, (unsigned long)blkoff, &blknum);

	up_read(&NILFS_MDT(dat)->mi_sem);	/* XXX */

	if (ret == 0) {	/* found */

		map_bh(bh_result, inode->i_sb, blknum);

		goto out;

	}

	if (unlikely(ret == 1)) {

		printk(KERN_ERR "nilfs_get_block: bmap_lookup returns "

		       "buffer_head pointer (blkoff=%llu, blknum=%lu)\n",

		       (unsigned long long)blkoff, blknum);

		BUG();

	}

	/* data block was not found */

	if (ret == -ENOENT && create) {

		struct nilfs_transaction_info ti;

		bh_result->b_blocknr = 0;

		err = nilfs_transaction_begin(inode->i_sb, &ti, 1);

		if (unlikely(err))

			goto out;

		err = nilfs_bmap_insert(ii->i_bmap, (unsigned long)blkoff,

					(unsigned long)bh_result);

		nilfs_transaction_end(inode->i_sb, !err);

		if (unlikely(err != 0)) {

			if (err == -EEXIST) {

				/*

				 * The get_block() function could be called

				 * from multiple callers for an inode.

				 * However, the page having this block must

				 * be locked in this case.

				 */

				printk(KERN_ERR

				       "nilfs_get_block: a race condition "

				       "while inserting a data block. "

				       "(inode number=%lu, file block "

				       "offset=%llu)\n",

				       inode->i_ino,

				       (unsigned long long)blkoff);

				BUG();

			} else if (err == -EINVAL) {

				nilfs_error(inode->i_sb, __func__,

					    "broken bmap (inode=%lu)\n",

					    inode->i_ino);

				err = -EIO;

			}

			goto out;

		}

		/* Error handling should be detailed */

		set_buffer_new(bh_result);

		map_bh(bh_result, inode->i_sb, 0); /* dbn must be changed

						      to proper value */

	} else if (ret == -ENOENT) {

		/* not found is not error (e.g. hole); must return without

		   the mapped state flag. */

		;

	} else {

		err = ret;

	}

 out:

	return err;

}

/**

 * nilfs_readpage() - implement readpage() method of nilfs_aops {}

 * address_space_operations.

 * @file - file struct of the file to be read

 * @page - the page to be read

 */

static int nilfs_readpage(struct file *file, struct page *page)

{

	return mpage_readpage(page, nilfs_get_block);

}

/**

 * nilfs_readpages() - implement readpages() method of nilfs_aops {}

 * address_space_operations.

 * @file - file struct of the file to be read

 * @mapping - address_space struct used for reading multiple pages

 * @pages - the pages to be read

 * @nr_pages - number of pages to be read

 */

static int nilfs_readpages(struct file *file, struct address_space *mapping,

			   struct list_head *pages, unsigned nr_pages)

{

	return mpage_readpages(mapping, pages, nr_pages, nilfs_get_block);

}

static int nilfs_writepages(struct address_space *mapping,

			    struct writeback_control *wbc)

{

	/* This empty method is required not to call generic_writepages() */

	return 0;

}

static int nilfs_writepage(struct page *page, struct writeback_control *wbc)

{

	struct inode *inode = page->mapping->host;

	int err;

	redirty_page_for_writepage(wbc, page);

	unlock_page(page);

	if (wbc->sync_mode == WB_SYNC_ALL) {

		err = nilfs_construct_segment(inode->i_sb);

		if (unlikely(err))

			return err;

	} else if (wbc->for_reclaim)

		nilfs_flush_segment(inode->i_sb, inode->i_ino);

	return 0;

}

static int nilfs_set_page_dirty(struct page *page)

{

	int ret = __set_page_dirty_buffers(page);

	if (ret) {

		struct inode *inode = page->mapping->host;

		struct nilfs_sb_info *sbi = NILFS_SB(inode->i_sb);

		unsigned nr_dirty = 1 << (PAGE_SHIFT - inode->i_blkbits);

		nilfs_set_file_dirty(sbi, inode, nr_dirty);

	}

	return ret;

}

static int nilfs_write_begin(struct file *file, struct address_space *mapping,

			     loff_t pos, unsigned len, unsigned flags,

			     struct page **pagep, void **fsdata)

{

	struct inode *inode = mapping->host;

	int err = nilfs_transaction_begin(inode->i_sb, NULL, 1);

	if (unlikely(err))

		return err;

	*pagep = NULL;

	err = block_write_begin(file, mapping, pos, len, flags, pagep,

				fsdata, nilfs_get_block);

	if (unlikely(err))

		nilfs_transaction_end(inode->i_sb, 0);

	return err;

}

static int nilfs_write_end(struct file *file, struct address_space *mapping,

			   loff_t pos, unsigned len, unsigned copied,

			   struct page *page, void *fsdata)

{

	struct inode *inode = mapping->host;

	unsigned start = pos & (PAGE_CACHE_SIZE - 1);

	unsigned nr_dirty;

	int err;

	nr_dirty = nilfs_page_count_clean_buffers(page, start,

						  start + copied);

	copied = generic_write_end(file, mapping, pos, len, copied, page,

				   fsdata);

	nilfs_set_file_dirty(NILFS_SB(inode->i_sb), inode, nr_dirty);

	err = nilfs_transaction_end(inode->i_sb, 1);

	return err ? : copied;

}

static ssize_t

nilfs_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov,

		loff_t offset, unsigned long nr_segs)

{

	struct file *file = iocb->ki_filp;

	struct inode *inode = file->f_mapping->host;

	ssize_t size;

	int err;

	err = nilfs_construct_dsync_segment(inode->i_sb, inode);

	if (unlikely(err))

		return err;

	if (rw == WRITE)

		return 0;

	/* Needs synchronization with the cleaner */

	size = blockdev_direct_IO(rw, iocb, inode, inode->i_sb->s_bdev, iov,

				  offset, nr_segs, nilfs_get_block, NULL);

	return size;

}

struct address_space_operations nilfs_aops = {

	.writepage		= nilfs_writepage,

	.readpage		= nilfs_readpage,

	/* .sync_page		= nilfs_sync_page, */

	.writepages		= nilfs_writepages,

	.set_page_dirty		= nilfs_set_page_dirty,

	.readpages		= nilfs_readpages,

	.write_begin		= nilfs_write_begin,

	.write_end		= nilfs_write_end,

	/* .releasepage		= nilfs_releasepage, */

	.invalidatepage		= block_invalidatepage,

	.direct_IO		= nilfs_direct_IO,

};

struct inode *nilfs_new_inode(struct inode *dir, int mode)

{

	struct super_block *sb = dir->i_sb;

	struct nilfs_sb_info *sbi = NILFS_SB(sb);

	struct inode *inode;

	struct nilfs_inode_info *ii;

	int err = -ENOMEM;

	ino_t ino;

	inode = new_inode(sb);

	if (unlikely(!inode))

		goto failed;

	mapping_set_gfp_mask(inode->i_mapping,

			     mapping_gfp_mask(inode->i_mapping) & ~__GFP_FS);

	ii = NILFS_I(inode);

	ii->i_state = 1 << NILFS_I_NEW;

	err = nilfs_ifile_create_inode(sbi->s_ifile, &ino, &ii->i_bh);

	if (unlikely(err))

		goto failed_ifile_create_inode;

	/* reference count of i_bh inherits from nilfs_mdt_read_block() */

	atomic_inc(&sbi->s_inodes_count);

	inode->i_uid = current_fsuid();

	if (dir->i_mode & S_ISGID) {

		inode->i_gid = dir->i_gid;

		if (S_ISDIR(mode))

			mode |= S_ISGID;

	} else

		inode->i_gid = current_fsgid();

	inode->i_mode = mode;

	inode->i_ino = ino;

	inode->i_mtime = inode->i_atime = inode->i_ctime = CURRENT_TIME;

	if (S_ISREG(mode) || S_ISDIR(mode) || S_ISLNK(mode)) {

		err = nilfs_bmap_read(ii->i_bmap, NULL);

		if (err < 0)

			goto failed_bmap;

		set_bit(NILFS_I_BMAP, &ii->i_state);

		/* No lock is needed; iget() ensures it. */

	}

	ii->i_flags = NILFS_I(dir)->i_flags;

	if (S_ISLNK(mode))

		ii->i_flags &= ~(NILFS_IMMUTABLE_FL | NILFS_APPEND_FL);

	if (!S_ISDIR(mode))

		ii->i_flags &= ~NILFS_DIRSYNC_FL;

	/* ii->i_file_acl = 0; */

	/* ii->i_dir_acl = 0; */

	ii->i_dtime = 0;

	ii->i_dir_start_lookup = 0;

#ifdef CONFIG_NILFS_FS_POSIX_ACL

	ii->i_acl = NULL;

	ii->i_default_acl = NULL;

#endif

	ii->i_cno = 0;

	nilfs_set_inode_flags(inode);

	spin_lock(&sbi->s_next_gen_lock);

	inode->i_generation = sbi->s_next_generation++;

	spin_unlock(&sbi->s_next_gen_lock);

	insert_inode_hash(inode);

	err = nilfs_init_acl(inode, dir);

	if (unlikely(err))

		goto failed_acl; /* never occur. When supporting

				    nilfs_init_acl(), proper cancellation of

				    above jobs should be considered */

	mark_inode_dirty(inode);

	return inode;

 failed_acl:

 failed_bmap:

	inode->i_nlink = 0;

	iput(inode);  /* raw_inode will be deleted through

			 generic_delete_inode() */

	goto failed;

 failed_ifile_create_inode:

	make_bad_inode(inode);

	iput(inode);  /* if i_nlink == 1, generic_forget_inode() will be

			 called */

 failed:

	return ERR_PTR(err);

}

void nilfs_free_inode(struct inode *inode)

{

	struct super_block *sb = inode->i_sb;

	struct nilfs_sb_info *sbi = NILFS_SB(sb);

	clear_inode(inode);

	/* XXX: check error code? Is there any thing I can do? */

	(void) nilfs_ifile_delete_inode(sbi->s_ifile, inode->i_ino);

	atomic_dec(&sbi->s_inodes_count);

}

void nilfs_set_inode_flags(struct inode *inode)

{

	unsigned int flags = NILFS_I(inode)->i_flags;

	inode->i_flags &= ~(S_SYNC | S_APPEND | S_IMMUTABLE | S_NOATIME |

			    S_DIRSYNC);

	if (flags & NILFS_SYNC_FL)

		inode->i_flags |= S_SYNC;

	if (flags & NILFS_APPEND_FL)

		inode->i_flags |= S_APPEND;

	if (flags & NILFS_IMMUTABLE_FL)

		inode->i_flags |= S_IMMUTABLE;

#ifndef NILFS_ATIME_DISABLE

	if (flags & NILFS_NOATIME_FL)

#endif

		inode->i_flags |= S_NOATIME;

	if (flags & NILFS_DIRSYNC_FL)

		inode->i_flags |= S_DIRSYNC;

	mapping_set_gfp_mask(inode->i_mapping,

			     mapping_gfp_mask(inode->i_mapping) & ~__GFP_FS);

}

int nilfs_read_inode_common(struct inode *inode,

			    struct nilfs_inode *raw_inode)

{

	struct nilfs_inode_info *ii = NILFS_I(inode);

	int err;

	inode->i_mode = le16_to_cpu(raw_inode->i_mode);

	inode->i_uid = (uid_t)le32_to_cpu(raw_inode->i_uid);

	inode->i_gid = (gid_t)le32_to_cpu(raw_inode->i_gid);

	inode->i_nlink = le16_to_cpu(raw_inode->i_links_count);

	inode->i_size = le64_to_cpu(raw_inode->i_size);

	inode->i_atime.tv_sec = le64_to_cpu(raw_inode->i_mtime);

	inode->i_ctime.tv_sec = le64_to_cpu(raw_inode->i_ctime);

	inode->i_mtime.tv_sec = le64_to_cpu(raw_inode->i_mtime);

	inode->i_atime.tv_nsec = 0;

	inode->i_ctime.tv_nsec = 0;

	inode->i_mtime.tv_nsec = 0;

	ii->i_dtime = le64_to_cpu(raw_inode->i_dtime);

	if (inode->i_nlink == 0 && (inode->i_mode == 0 || ii->i_dtime))

		return -EINVAL; /* this inode is deleted */

	inode->i_blocks = le64_to_cpu(raw_inode->i_blocks);

	ii->i_flags = le32_to_cpu(raw_inode->i_flags);

#if 0

	ii->i_file_acl = le32_to_cpu(raw_inode->i_file_acl);

	ii->i_dir_acl = S_ISREG(inode->i_mode) ?

		0 : le32_to_cpu(raw_inode->i_dir_acl);

#endif

	ii->i_cno = 0;

	inode->i_generation = le32_to_cpu(raw_inode->i_generation);

	if (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||

	    S_ISLNK(inode->i_mode)) {

		err = nilfs_bmap_read(ii->i_bmap, raw_inode);

		if (err < 0)

			return err;

		set_bit(NILFS_I_BMAP, &ii->i_state);

		/* No lock is needed; iget() ensures it. */

	}

	return 0;

}

static int nilfs_read_sketch_inode(struct inode *inode)

{

	struct nilfs_sb_info *sbi = NILFS_SB(inode->i_sb);

	int err = 0;

	if (sbi->s_snapshot_cno) {

		struct the_nilfs *nilfs = sbi->s_nilfs;

		struct buffer_head *bh_cp;

		struct nilfs_checkpoint *raw_cp;

		err = nilfs_cpfile_get_checkpoint(

			nilfs->ns_cpfile, sbi->s_snapshot_cno, 0, &raw_cp,

			&bh_cp);

		if (likely(!err)) {

			if (!nilfs_checkpoint_sketch(raw_cp))

				inode->i_size = 0;

			nilfs_cpfile_put_checkpoint(

				nilfs->ns_cpfile, sbi->s_snapshot_cno, bh_cp);

		}

		inode->i_flags |= S_NOCMTIME;

	}

	return err;

}

static int __nilfs_read_inode(struct super_block *sb, unsigned long ino,

			      struct inode *inode)

{

	struct nilfs_sb_info *sbi = NILFS_SB(sb);

	struct inode *dat = nilfs_dat_inode(sbi->s_nilfs);

	struct buffer_head *bh;

	struct nilfs_inode *raw_inode;

	int err;

	down_read(&NILFS_MDT(dat)->mi_sem);	/* XXX */

	err = nilfs_ifile_get_inode_block(sbi->s_ifile, ino, &bh);

	if (unlikely(err))

		goto bad_inode;

	raw_inode = nilfs_ifile_map_inode(sbi->s_ifile, ino, bh);

#ifdef CONFIG_NILFS_FS_POSIX_ACL

	ii->i_acl = NILFS_ACL_NOT_CACHED;

	ii->i_default_acl = NILFS_ACL_NOT_CACHED;

#endif

	if (nilfs_read_inode_common(inode, raw_inode))

		goto failed_unmap;

	if (S_ISREG(inode->i_mode)) {

		inode->i_op = &nilfs_file_inode_operations;

		inode->i_fop = &nilfs_file_operations;

		inode->i_mapping->a_ops = &nilfs_aops;

		if (unlikely(inode->i_ino == NILFS_SKETCH_INO)) {

			err = nilfs_read_sketch_inode(inode);

			if (unlikely(err))

				goto failed_unmap;

		}

	} else if (S_ISDIR(inode->i_mode)) {

		inode->i_op = &nilfs_dir_inode_operations;

		inode->i_fop = &nilfs_dir_operations;

		inode->i_mapping->a_ops = &nilfs_aops;

	} else if (S_ISLNK(inode->i_mode)) {

		inode->i_op = &nilfs_symlink_inode_operations;

		inode->i_mapping->a_ops = &nilfs_aops;

	} else {

		inode->i_op = &nilfs_special_inode_operations;

		init_special_inode(

			inode, inode->i_mode,

			new_decode_dev(le64_to_cpu(raw_inode->i_device_code)));

	}

	nilfs_ifile_unmap_inode(sbi->s_ifile, ino, bh);

	brelse(bh);

	up_read(&NILFS_MDT(dat)->mi_sem);	/* XXX */

	nilfs_set_inode_flags(inode);

	return 0;

 failed_unmap:

	nilfs_ifile_unmap_inode(sbi->s_ifile, ino, bh);

	brelse(bh);

 bad_inode:

	up_read(&NILFS_MDT(dat)->mi_sem);	/* XXX */

	return err;

}

struct inode *nilfs_iget(struct super_block *sb, unsigned long ino)

{

	struct inode *inode;

	int err;

	inode = iget_locked(sb, ino);

	if (unlikely(!inode))

		return ERR_PTR(-ENOMEM);

	if (!(inode->i_state & I_NEW))

		return inode;

	err = __nilfs_read_inode(sb, ino, inode);

	if (unlikely(err)) {

		iget_failed(inode);

		return ERR_PTR(err);

	}

	unlock_new_inode(inode);

	return inode;

}

void nilfs_write_inode_common(struct inode *inode,

			      struct nilfs_inode *raw_inode, int has_bmap)

{

	struct nilfs_inode_info *ii = NILFS_I(inode);

	raw_inode->i_mode = cpu_to_le16(inode->i_mode);

	raw_inode->i_uid = cpu_to_le32(inode->i_uid);

	raw_inode->i_gid = cpu_to_le32(inode->i_gid);

	raw_inode->i_links_count = cpu_to_le16(inode->i_nlink);

	raw_inode->i_size = cpu_to_le64(inode->i_size);

	raw_inode->i_ctime = cpu_to_le64(inode->i_ctime.tv_sec);

	raw_inode->i_mtime = cpu_to_le64(inode->i_mtime.tv_sec);

	raw_inode->i_blocks = cpu_to_le64(inode->i_blocks);

	raw_inode->i_dtime = cpu_to_le64(ii->i_dtime);

	raw_inode->i_flags = cpu_to_le32(ii->i_flags);

	raw_inode->i_generation = cpu_to_le32(inode->i_generation);

	if (has_bmap)

		nilfs_bmap_write(ii->i_bmap, raw_inode);

	else if (S_ISCHR(inode->i_mode) || S_ISBLK(inode->i_mode))

		raw_inode->i_device_code =

			cpu_to_le64(new_encode_dev(inode->i_rdev));

	/* When extending inode, nilfs->ns_inode_size should be checked

	   for substitutions of appended fields */

}

void nilfs_update_inode(struct inode *inode, struct buffer_head *ibh)

{

	ino_t ino = inode->i_ino;

	struct nilfs_inode_info *ii = NILFS_I(inode);

	struct super_block *sb = inode->i_sb;

	struct nilfs_sb_info *sbi = NILFS_SB(sb);

	struct nilfs_inode *raw_inode;

	raw_inode = nilfs_ifile_map_inode(sbi->s_ifile, ino, ibh);

	/* The buffer is guarded with lock_buffer() by the caller */

	if (test_and_clear_bit(NILFS_I_NEW, &ii->i_state))

		memset(raw_inode, 0, NILFS_MDT(sbi->s_ifile)->mi_entry_size);

	set_bit(NILFS_I_INODE_DIRTY, &ii->i_state);

	nilfs_write_inode_common(inode, raw_inode, 0);

		/* XXX: call with has_bmap = 0 is a workaround to avoid

		   deadlock of bmap. This delays update of i_bmap to just

		   before writing */

	nilfs_ifile_unmap_inode(sbi->s_ifile, ino, ibh);

}

#define NILFS_MAX_TRUNCATE_BLOCKS	16384  /* 64MB for 4KB block */

static void nilfs_truncate_bmap(struct nilfs_inode_info *ii,

				unsigned long from)

{

	unsigned long b;

	int ret;

	if (!test_bit(NILFS_I_BMAP, &ii->i_state))

		return;

 repeat:

	ret = nilfs_bmap_last_key(ii->i_bmap, &b);

	if (ret == -ENOENT)

		return;

	else if (ret < 0)

		goto failed;

	if (b < from)

		return;

	b -= min_t(unsigned long, NILFS_MAX_TRUNCATE_BLOCKS, b - from);

	ret = nilfs_bmap_truncate(ii->i_bmap, b);

	nilfs_relax_pressure_in_lock(ii->vfs_inode.i_sb);

	if (!ret || (ret == -ENOMEM &&

		     nilfs_bmap_truncate(ii->i_bmap, b) == 0))

		goto repeat;

 failed:

	if (ret == -EINVAL)

		nilfs_error(ii->vfs_inode.i_sb, __func__,

			    "bmap is broken (ino=%lu)", ii->vfs_inode.i_ino);

	else

		nilfs_warning(ii->vfs_inode.i_sb, __func__,

			      "failed to truncate bmap (ino=%lu, err=%d)",

			      ii->vfs_inode.i_ino, ret);

}

void nilfs_truncate(struct inode *inode)

{

	unsigned long blkoff;

	unsigned int blocksize;

	struct nilfs_transaction_info ti;

	struct super_block *sb = inode->i_sb;

	struct nilfs_inode_info *ii = NILFS_I(inode);

	int ret;

	if (!test_bit(NILFS_I_BMAP, &ii->i_state))

		return;

	if (IS_APPEND(inode) || IS_IMMUTABLE(inode))

		return;

	blocksize = sb->s_blocksize;

	blkoff = (inode->i_size + blocksize - 1) >> sb->s_blocksize_bits;

	ret = nilfs_transaction_begin(sb, &ti, 0);

	BUG_ON(ret);

	block_truncate_page(inode->i_mapping, inode->i_size, nilfs_get_block);

	nilfs_truncate_bmap(ii, blkoff);

	inode->i_mtime = inode->i_ctime = CURRENT_TIME;

	if (IS_SYNC(inode))

		nilfs_set_transaction_flag(NILFS_TI_SYNC);

	nilfs_set_file_dirty(NILFS_SB(sb), inode, 0);

	nilfs_transaction_end(sb, 1);

	/* May construct a logical segment and may fail in sync mode.

	   But truncate has no return value. */

}

void nilfs_delete_inode(struct inode *inode)

{

	struct nilfs_transaction_info ti;

	struct super_block *sb = inode->i_sb;

	struct nilfs_inode_info *ii = NILFS_I(inode);

	int err;

	if (unlikely(is_bad_inode(inode))) {

		if (inode->i_data.nrpages)

			truncate_inode_pages(&inode->i_data, 0);

		clear_inode(inode);

		return;

	}

	err = nilfs_transaction_begin(sb, &ti, 0);

	BUG_ON(err);

	if (inode->i_data.nrpages)

		truncate_inode_pages(&inode->i_data, 0);

	nilfs_truncate_bmap(ii, 0);

	nilfs_free_inode(inode);

	/* nilfs_free_inode() marks inode buffer dirty */

	if (IS_SYNC(inode))