inode.c

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/*
 * 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 <[email protected]>
 *
 */

#include <linux/buffer_head.h>
#include <linux/gfp.h>
#include <linux/mpage.h>
#include <linux/writeback.h>
#include <linux/uio.h>
#include "nilfs.h"
#include "btnode.h"
#include "segment.h"
#include "page.h"
#include "mdt.h"
#include "cpfile.h"
#include "ifile.h"

struct nilfs_iget_args {
    u64 ino;
    __u64 cno;
    struct nilfs_root *root;
    int for_gc;
};

void nilfs_inode_add_blocks(struct inode *inode, int n)
{
    struct nilfs_root *root = NILFS_I(inode)->i_root;

    inode_add_bytes(inode, (1 << inode->i_blkbits) * n);
    if (root)
        atomic_add(n, &root->blocks_count);
}

void nilfs_inode_sub_blocks(struct inode *inode, int n)
{
    struct nilfs_root *root = NILFS_I(inode)->i_root;

    inode_sub_bytes(inode, (1 << inode->i_blkbits) * n);
    if (root)
        atomic_sub(n, &root->blocks_count);
}

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);
    struct the_nilfs *nilfs = inode->i_sb->s_fs_info;
    __u64 blknum = 0;
    int err = 0, ret;
    unsigned maxblocks = bh_result->b_size >> inode->i_blkbits;

    down_read(&NILFS_MDT(nilfs->ns_dat)->mi_sem);
    ret = nilfs_bmap_lookup_contig(ii->i_bmap, blkoff, &blknum, maxblocks);
    up_read(&NILFS_MDT(nilfs->ns_dat)->mi_sem);
    if (ret >= 0) { /* found */
        map_bh(bh_result, inode->i_sb, blknum);
        if (ret > 0)
            bh_result->b_size = (ret << inode->i_blkbits);
        goto out;
    }
    /* 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);
        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_WARNING
                       "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);
                err = 0;
            }
            nilfs_transaction_abort(inode->i_sb);
            goto out;
        }
        nilfs_mark_inode_dirty(inode);
        nilfs_transaction_commit(inode->i_sb); /* never fails */
        /* Error handling should be detailed */
        set_buffer_new(bh_result);
        set_buffer_delay(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;
}

static int nilfs_readpage(struct file *file, struct page *page)
{
    return mpage_readpage(page, nilfs_get_block);
}

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)
{
    struct inode *inode = mapping->host;
    int err = 0;

    if (wbc->sync_mode == WB_SYNC_ALL)
        err = nilfs_construct_dsync_segment(inode->i_sb, inode,
                            wbc->range_start,
                            wbc->range_end);
    return err;
}

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

        nilfs_set_file_dirty(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;

    err = block_write_begin(mapping, pos, len, flags, pagep,
                nilfs_get_block);
    if (unlikely(err)) {
        loff_t isize = mapping->host->i_size;
        if (pos + len > isize)
            vmtruncate(mapping->host, isize);

        nilfs_transaction_abort(inode->i_sb);
    }
    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(inode, nr_dirty);
    err = nilfs_transaction_commit(inode->i_sb);
    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;

    if (rw == WRITE)
        return 0;

    /* Needs synchronization with the cleaner */
    size = blockdev_direct_IO(rw, iocb, inode, iov, offset, nr_segs,
                  nilfs_get_block);

    /*
     * In case of error extending write may have instantiated a few
     * blocks outside i_size. Trim these off again.
     */
    if (unlikely((rw & WRITE) && size < 0)) {
        loff_t isize = i_size_read(inode);
        loff_t end = offset + iov_length(iov, nr_segs);

        if (end > isize)
            vmtruncate(inode, isize);
    }

    return size;
}

const struct address_space_operations nilfs_aops = {
    .writepage      = nilfs_writepage,
    .readpage       = nilfs_readpage,
    .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,
    .is_partially_uptodate  = block_is_partially_uptodate,
};

struct inode *nilfs_new_inode(struct inode *dir, umode_t mode)
{
    struct super_block *sb = dir->i_sb;
    struct the_nilfs *nilfs = sb->s_fs_info;
    struct inode *inode;
    struct nilfs_inode_info *ii;
    struct nilfs_root *root;
    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);

    root = NILFS_I(dir)->i_root;
    ii = NILFS_I(inode);
    ii->i_state = 1 << NILFS_I_NEW;
    ii->i_root = root;

    err = nilfs_ifile_create_inode(root->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(&root->inodes_count);
    inode_init_owner(inode, dir, 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_mask_flags(
        mode, NILFS_I(dir)->i_flags & NILFS_FL_INHERITED);

    /* ii->i_file_acl = 0; */
    /* ii->i_dir_acl = 0; */
    ii->i_dir_start_lookup = 0;
    nilfs_set_inode_flags(inode);
    spin_lock(&nilfs->ns_next_gen_lock);
    inode->i_generation = nilfs->ns_next_generation++;
    spin_unlock(&nilfs->ns_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 */

    return inode;

 failed_acl:
 failed_bmap:
    clear_nlink(inode);
    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_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 & FS_SYNC_FL)
        inode->i_flags |= S_SYNC;
    if (flags & FS_APPEND_FL)
        inode->i_flags |= S_APPEND;
    if (flags & FS_IMMUTABLE_FL)
        inode->i_flags |= S_IMMUTABLE;
    if (flags & FS_NOATIME_FL)
        inode->i_flags |= S_NOATIME;
    if (flags & FS_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);
    i_uid_write(inode, le32_to_cpu(raw_inode->i_uid));
    i_gid_write(inode, le32_to_cpu(raw_inode->i_gid));
    set_nlink(inode, 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 = le32_to_cpu(raw_inode->i_mtime_nsec);
    inode->i_ctime.tv_nsec = le32_to_cpu(raw_inode->i_ctime_nsec);
    inode->i_mtime.tv_nsec = le32_to_cpu(raw_inode->i_mtime_nsec);
    if (inode->i_nlink == 0 && inode->i_mode == 0)
        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_dir_start_lookup = 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_inode(struct super_block *sb,
                  struct nilfs_root *root, unsigned long ino,
                  struct inode *inode)
{
    struct the_nilfs *nilfs = sb->s_fs_info;
    struct buffer_head *bh;
    struct nilfs_inode *raw_inode;
    int err;

    down_read(&NILFS_MDT(nilfs->ns_dat)->mi_sem);
    err = nilfs_ifile_get_inode_block(root->ifile, ino, &bh);
    if (unlikely(err))
        goto bad_inode;

    raw_inode = nilfs_ifile_map_inode(root->ifile, ino, bh);

    err = nilfs_read_inode_common(inode, raw_inode);
    if (err)
        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;
    } 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,
            huge_decode_dev(le64_to_cpu(raw_inode->i_device_code)));
    }
    nilfs_ifile_unmap_inode(root->ifile, ino, bh);
    brelse(bh);
    up_read(&NILFS_MDT(nilfs->ns_dat)->mi_sem);
    nilfs_set_inode_flags(inode);
    return 0;

 failed_unmap:
    nilfs_ifile_unmap_inode(root->ifile, ino, bh);
    brelse(bh);

 bad_inode:
    up_read(&NILFS_MDT(nilfs->ns_dat)->mi_sem);
    return err;
}

static int nilfs_iget_test(struct inode *inode, void *opaque)
{
    struct nilfs_iget_args *args = opaque;
    struct nilfs_inode_info *ii;

    if (args->ino != inode->i_ino || args->root != NILFS_I(inode)->i_root)
        return 0;

    ii = NILFS_I(inode);
    if (!test_bit(NILFS_I_GCINODE, &ii->i_state))
        return !args->for_gc;

    return args->for_gc && args->cno == ii->i_cno;
}

static int nilfs_iget_set(struct inode *inode, void *opaque)
{
    struct nilfs_iget_args *args = opaque;

    inode->i_ino = args->ino;
    if (args->for_gc) {
        NILFS_I(inode)->i_state = 1 << NILFS_I_GCINODE;
        NILFS_I(inode)->i_cno = args->cno;
        NILFS_I(inode)->i_root = NULL;
    } else {
        if (args->root && args->ino == NILFS_ROOT_INO)
            nilfs_get_root(args->root);
        NILFS_I(inode)->i_root = args->root;
    }
    return 0;
}

struct inode *nilfs_ilookup(struct super_block *sb, struct nilfs_root *root,
                unsigned long ino)
{
    struct nilfs_iget_args args = {
        .ino = ino, .root = root, .cno = 0, .for_gc = 0
    };

    return ilookup5(sb, ino, nilfs_iget_test, &args);
}

struct inode *nilfs_iget_locked(struct super_block *sb, struct nilfs_root *root,
                unsigned long ino)
{
    struct nilfs_iget_args args = {
        .ino = ino, .root = root, .cno = 0, .for_gc = 0
    };

    return iget5_locked(sb, ino, nilfs_iget_test, nilfs_iget_set, &args);
}

struct inode *nilfs_iget(struct super_block *sb, struct nilfs_root *root,
             unsigned long ino)
{
    struct inode *inode;
    int err;

    inode = nilfs_iget_locked(sb, root, ino);
    if (unlikely(!inode))
        return ERR_PTR(-ENOMEM);
    if (!(inode->i_state & I_NEW))
        return inode;

    err = __nilfs_read_inode(sb, root, ino, inode);
    if (unlikely(err)) {
        iget_failed(inode);
        return ERR_PTR(err);
    }
    unlock_new_inode(inode);
    return inode;
}

struct inode *nilfs_iget_for_gc(struct super_block *sb, unsigned long ino,
                __u64 cno)
{
    struct nilfs_iget_args args = {
        .ino = ino, .root = NULL, .cno = cno, .for_gc = 1
    };
    struct inode *inode;
    int err;

    inode = iget5_locked(sb, ino, nilfs_iget_test, nilfs_iget_set, &args);
    if (unlikely(!inode))
        return ERR_PTR(-ENOMEM);
    if (!(inode->i_state & I_NEW))
        return inode;

    err = nilfs_init_gcinode(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(i_uid_read(inode));
    raw_inode->i_gid = cpu_to_le32(i_gid_read(inode));
    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_ctime_nsec = cpu_to_le32(inode->i_ctime.tv_nsec);
    raw_inode->i_mtime_nsec = cpu_to_le32(inode->i_mtime.tv_nsec);
    raw_inode->i_blocks = cpu_to_le64(inode->i_blocks);

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

    if (NILFS_ROOT_METADATA_FILE(inode->i_ino)) {
        struct the_nilfs *nilfs = inode->i_sb->s_fs_info;

        /* zero-fill unused portion in the case of super root block */
        raw_inode->i_xattr = 0;
        raw_inode->i_pad = 0;
        memset((void *)raw_inode + sizeof(*raw_inode), 0,
               nilfs->ns_inode_size - sizeof(*raw_inode));
    }

    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(huge_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 inode *ifile = ii->i_root->ifile;
    struct nilfs_inode *raw_inode;

    raw_inode = nilfs_ifile_map_inode(ifile, ino, ibh);

    if (test_and_clear_bit(NILFS_I_NEW, &ii->i_state))
        memset(raw_inode, 0, NILFS_MDT(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(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:
    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);

    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;
    nilfs_transaction_begin(sb, &ti, 0); /* never fails */

    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_mark_inode_dirty(inode);
    nilfs_set_file_dirty(inode, 0);
    nilfs_transaction_commit(sb);
    /* May construct a logical segment and may fail in sync mode.
       But truncate has no return value. */
}

static void nilfs_clear_inode(struct inode *inode)
{
    struct nilfs_inode_info *ii = NILFS_I(inode);
    struct nilfs_mdt_info *mdi = NILFS_MDT(inode);

    /*
     * Free resources allocated in nilfs_read_inode(), here.
     */
    BUG_ON(!list_empty(&ii->i_dirty));
    brelse(ii->i_bh);
    ii->i_bh = NULL;

    if (mdi && mdi->mi_palloc_cache)
        nilfs_palloc_destroy_cache(inode);

    if (test_bit(NILFS_I_BMAP, &ii->i_state))
        nilfs_bmap_clear(ii->i_bmap);

    nilfs_btnode_cache_clear(&ii->i_btnode_cache);

    if (ii->i_root && inode->i_ino == NILFS_ROOT_INO)
        nilfs_put_root(ii->i_root);
}

void nilfs_evict_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 ret;

    if (inode->i_nlink || !ii->i_root || unlikely(is_bad_inode(inode))) {
        if (inode->i_data.nrpages)
            truncate_inode_pages(&inode->i_data, 0);
        clear_inode(inode);
        nilfs_clear_inode(inode);
        return;
    }
    nilfs_transaction_begin(sb, &ti, 0); /* never fails */

    if (inode->i_data.nrpages)
        truncate_inode_pages(&inode->i_data, 0);

    /* TODO: some of the following operations may fail.  */
    nilfs_truncate_bmap(ii, 0);
    nilfs_mark_inode_dirty(inode);
    clear_inode(inode);

    ret = nilfs_ifile_delete_inode(ii->i_root->ifile, inode->i_ino);
    if (!ret)
        atomic_dec(&ii->i_root->inodes_count);

    nilfs_clear_inode(inode);

    if (IS_SYNC(inode))
        nilfs_set_transaction_flag(NILFS_TI_SYNC);
    nilfs_transaction_commit(sb);
    /* May construct a logical segment and may fail in sync mode.
       But delete_inode has no return value. */
}

int nilfs_setattr(struct dentry *dentry, struct iattr *iattr)
{
    struct nilfs_transaction_info ti;
    struct inode *inode = dentry->d_inode;
    struct super_block *sb = inode->i_sb;
    int err;

    err = inode_change_ok(inode, iattr);
    if (err)
        return err;

    err = nilfs_transaction_begin(sb, &ti, 0);
    if (unlikely(err))
        return err;

    if ((iattr->ia_valid & ATTR_SIZE) &&
        iattr->ia_size != i_size_read(inode)) {
        inode_dio_wait(inode);

        err = vmtruncate(inode, iattr->ia_size);
        if (unlikely(err))
            goto out_err;
    }

    setattr_copy(inode, iattr);
    mark_inode_dirty(inode);

    if (iattr->ia_valid & ATTR_MODE) {
        err = nilfs_acl_chmod(inode);
        if (unlikely(err))
            goto out_err;
    }

    return nilfs_transaction_commit(sb);

out_err:
    nilfs_transaction_abort(sb);
    return err;
}

int nilfs_permission(struct inode *inode, int mask)
{
    struct nilfs_root *root = NILFS_I(inode)->i_root;
    if ((mask & MAY_WRITE) && root &&
        root->cno != NILFS_CPTREE_CURRENT_CNO)
        return -EROFS; /* snapshot is not writable */

    return generic_permission(inode, mask);
}

int nilfs_load_inode_block(struct inode *inode, struct buffer_head **pbh)
{
    struct the_nilfs *nilfs = inode->i_sb->s_fs_info;
    struct nilfs_inode_info *ii = NILFS_I(inode);
    int err;

    spin_lock(&nilfs->ns_inode_lock);
    if (ii->i_bh == NULL) {
        spin_unlock(&nilfs->ns_inode_lock);
        err = nilfs_ifile_get_inode_block(ii->i_root->ifile,
                          inode->i_ino, pbh);
        if (unlikely(err))
            return err;
        spin_lock(&nilfs->ns_inode_lock);
        if (ii->i_bh == NULL)
            ii->i_bh = *pbh;
        else {
            brelse(*pbh);
            *pbh = ii->i_bh;
        }
    } else
        *pbh = ii->i_bh;

    get_bh(*pbh);
    spin_unlock(&nilfs->ns_inode_lock);
    return 0;
}

int nilfs_inode_dirty(struct inode *inode)
{
    struct nilfs_inode_info *ii = NILFS_I(inode);
    struct the_nilfs *nilfs = inode->i_sb->s_fs_info;
    int ret = 0;

    if (!list_empty(&ii->i_dirty)) {
        spin_lock(&nilfs->ns_inode_lock);
        ret = test_bit(NILFS_I_DIRTY, &ii->i_state) ||
            test_bit(NILFS_I_BUSY, &ii->i_state);
        spin_unlock(&nilfs->ns_inode_lock);
    }
    return ret;
}

int nilfs_set_file_dirty(struct inode *inode, unsigned nr_dirty)
{
    struct nilfs_inode_info *ii = NILFS_I(inode);
    struct the_nilfs *nilfs = inode->i_sb->s_fs_info;

    atomic_add(nr_dirty, &nilfs->ns_ndirtyblks);

    if (test_and_set_bit(NILFS_I_DIRTY, &ii->i_state))
        return 0;

    spin_lock(&nilfs->ns_inode_lock);
    if (!test_bit(NILFS_I_QUEUED, &ii->i_state) &&
        !test_bit(NILFS_I_BUSY, &ii->i_state)) {
        /* Because this routine may race with nilfs_dispose_list(),
           we have to check NILFS_I_QUEUED here, too. */
        if (list_empty(&ii->i_dirty) && igrab(inode) == NULL) {
            /* This will happen when somebody is freeing
               this inode. */
            nilfs_warning(inode->i_sb, __func__,
                      "cannot get inode (ino=%lu)\n",
                      inode->i_ino);
            spin_unlock(&nilfs->ns_inode_lock);
            return -EINVAL; /* NILFS_I_DIRTY may remain for
                       freeing inode */
        }
        list_move_tail(&ii->i_dirty, &nilfs->ns_dirty_files);
        set_bit(NILFS_I_QUEUED, &ii->i_state);
    }
    spin_unlock(&nilfs->ns_inode_lock);
    return 0;
}

int nilfs_mark_inode_dirty(struct inode *inode)
{
    struct buffer_head *ibh;
    int err;

    err = nilfs_load_inode_block(inode, &ibh);
    if (unlikely(err)) {
        nilfs_warning(inode->i_sb, __func__,
                  "failed to reget inode block.\n");
        return err;
    }
    nilfs_update_inode(inode, ibh);
    mark_buffer_dirty(ibh);
    nilfs_mdt_mark_dirty(NILFS_I(inode)->i_root->ifile);
    brelse(ibh);
    return 0;
}

void nilfs_dirty_inode(struct inode *inode, int flags)
{
    struct nilfs_transaction_info ti;
    struct nilfs_mdt_info *mdi = NILFS_MDT(inode);

    if (is_bad_inode(inode)) {
        nilfs_warning(inode->i_sb, __func__,
                  "tried to mark bad_inode dirty. ignored.\n");
        dump_stack();
        return;
    }
    if (mdi) {
        nilfs_mdt_mark_dirty(inode);
        return;
    }
    nilfs_transaction_begin(inode->i_sb, &ti, 0);
    nilfs_mark_inode_dirty(inode);
    nilfs_transaction_commit(inode->i_sb); /* never fails */
}

int nilfs_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
         __u64 start, __u64 len)
{
    struct the_nilfs *nilfs = inode->i_sb->s_fs_info;
    __u64 logical = 0, phys = 0, size = 0;
    __u32 flags = 0;
    loff_t isize;
    sector_t blkoff, end_blkoff;
    sector_t delalloc_blkoff;
    unsigned long delalloc_blklen;
    unsigned int blkbits = inode->i_blkbits;
    int ret, n;

    ret = fiemap_check_flags(fieinfo, FIEMAP_FLAG_SYNC);
    if (ret)
        return ret;

    mutex_lock(&inode->i_mutex);

    isize = i_size_read(inode);

    blkoff = start >> blkbits;
    end_blkoff = (start + len - 1) >> blkbits;

    delalloc_blklen = nilfs_find_uncommitted_extent(inode, blkoff,
                            &delalloc_blkoff);

    do {
        __u64 blkphy;
        unsigned int maxblocks;

        if (delalloc_blklen && blkoff == delalloc_blkoff) {
            if (size) {
                /* End of the current extent */
                ret = fiemap_fill_next_extent(
                    fieinfo, logical, phys, size, flags);
                if (ret)
                    break;
            }
            if (blkoff > end_blkoff)
                break;

            flags = FIEMAP_EXTENT_MERGED | FIEMAP_EXTENT_DELALLOC;
            logical = blkoff << blkbits;
            phys = 0;
            size = delalloc_blklen << blkbits;

            blkoff = delalloc_blkoff + delalloc_blklen;
            delalloc_blklen = nilfs_find_uncommitted_extent(
                inode, blkoff, &delalloc_blkoff);
            continue;
        }

        /*
         * Limit the number of blocks that we look up so as
         * not to get into the next delayed allocation extent.
         */
        maxblocks = INT_MAX;
        if (delalloc_blklen)
            maxblocks = min_t(sector_t, delalloc_blkoff - blkoff,
                      maxblocks);
        blkphy = 0;

        down_read(&NILFS_MDT(nilfs->ns_dat)->mi_sem);
        n = nilfs_bmap_lookup_contig(
            NILFS_I(inode)->i_bmap, blkoff, &blkphy, maxblocks);
        up_read(&NILFS_MDT(nilfs->ns_dat)->mi_sem);

        if (n < 0) {
            int past_eof;

            if (unlikely(n != -ENOENT))
                break; /* error */

            /* HOLE */
            blkoff++;
            past_eof = ((blkoff << blkbits) >= isize);

            if (size) {
                /* End of the current extent */

                if (past_eof)
                    flags |= FIEMAP_EXTENT_LAST;

                ret = fiemap_fill_next_extent(
                    fieinfo, logical, phys, size, flags);
                if (ret)
                    break;
                size = 0;
            }
            if (blkoff > end_blkoff || past_eof)
                break;
        } else {
            if (size) {
                if (phys && blkphy << blkbits == phys + size) {
                    /* The current extent goes on */
                    size += n << blkbits;
                } else {
                    /* Terminate the current extent */
                    ret = fiemap_fill_next_extent(
                        fieinfo, logical, phys, size,
                        flags);
                    if (ret || blkoff > end_blkoff)
                        break;

                    /* Start another extent */
                    flags = FIEMAP_EXTENT_MERGED;
                    logical = blkoff << blkbits;
                    phys = blkphy << blkbits;
                    size = n << blkbits;
                }
            } else {
                /* Start a new extent */
                flags = FIEMAP_EXTENT_MERGED;
                logical = blkoff << blkbits;
                phys = blkphy << blkbits;
                size = n << blkbits;
            }
            blkoff += n;
        }
        cond_resched();
    } while (true);

    /* If ret is 1 then we just hit the end of the extent array */
    if (ret == 1)
        ret = 0;

    mutex_unlock(&inode->i_mutex);
    return ret;
}