inode.c

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/*
 *   Copyright (C) International Business Machines Corp., 2000-2004
 *   Portions Copyright (C) Christoph Hellwig, 2001-2002
 *
 *   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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */

#include <linux/fs.h>
#include <linux/mpage.h>
#include <linux/buffer_head.h>
#include <linux/pagemap.h>
#include <linux/quotaops.h>
#include <linux/writeback.h>
#include "jfs_incore.h"
#include "jfs_inode.h"
#include "jfs_filsys.h"
#include "jfs_imap.h"
#include "jfs_extent.h"
#include "jfs_unicode.h"
#include "jfs_debug.h"


struct inode *jfs_iget(struct super_block *sb, unsigned long ino)
{
    struct inode *inode;
    int ret;

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

    ret = diRead(inode);
    if (ret < 0) {
        iget_failed(inode);
        return ERR_PTR(ret);
    }

    if (S_ISREG(inode->i_mode)) {
        inode->i_op = &jfs_file_inode_operations;
        inode->i_fop = &jfs_file_operations;
        inode->i_mapping->a_ops = &jfs_aops;
    } else if (S_ISDIR(inode->i_mode)) {
        inode->i_op = &jfs_dir_inode_operations;
        inode->i_fop = &jfs_dir_operations;
    } else if (S_ISLNK(inode->i_mode)) {
        if (inode->i_size >= IDATASIZE) {
            inode->i_op = &page_symlink_inode_operations;
            inode->i_mapping->a_ops = &jfs_aops;
        } else {
            inode->i_op = &jfs_fast_symlink_inode_operations;
            /*
             * The inline data should be null-terminated, but
             * don't let on-disk corruption crash the kernel
             */
            JFS_IP(inode)->i_inline[inode->i_size] = '\0';
        }
    } else {
        inode->i_op = &jfs_file_inode_operations;
        init_special_inode(inode, inode->i_mode, inode->i_rdev);
    }
    unlock_new_inode(inode);
    return inode;
}

/*
 * Workhorse of both fsync & write_inode
 */
int jfs_commit_inode(struct inode *inode, int wait)
{
    int rc = 0;
    tid_t tid;
    static int noisy = 5;

    jfs_info("In jfs_commit_inode, inode = 0x%p", inode);

    /*
     * Don't commit if inode has been committed since last being
     * marked dirty, or if it has been deleted.
     */
    if (inode->i_nlink == 0 || !test_cflag(COMMIT_Dirty, inode))
        return 0;

    if (isReadOnly(inode)) {
        /* kernel allows writes to devices on read-only
         * partitions and may think inode is dirty
         */
        if (!special_file(inode->i_mode) && noisy) {
            jfs_err("jfs_commit_inode(0x%p) called on "
                   "read-only volume", inode);
            jfs_err("Is remount racy?");
            noisy--;
        }
        return 0;
    }

    tid = txBegin(inode->i_sb, COMMIT_INODE);
    mutex_lock(&JFS_IP(inode)->commit_mutex);

    /*
     * Retest inode state after taking commit_mutex
     */
    if (inode->i_nlink && test_cflag(COMMIT_Dirty, inode))
        rc = txCommit(tid, 1, &inode, wait ? COMMIT_SYNC : 0);

    txEnd(tid);
    mutex_unlock(&JFS_IP(inode)->commit_mutex);
    return rc;
}

int jfs_write_inode(struct inode *inode, struct writeback_control *wbc)
{
    int wait = wbc->sync_mode == WB_SYNC_ALL;

    if (test_cflag(COMMIT_Nolink, inode))
        return 0;
    /*
     * If COMMIT_DIRTY is not set, the inode isn't really dirty.
     * It has been committed since the last change, but was still
     * on the dirty inode list.
     */
     if (!test_cflag(COMMIT_Dirty, inode)) {
        /* Make sure committed changes hit the disk */
        jfs_flush_journal(JFS_SBI(inode->i_sb)->log, wait);
        return 0;
     }

    if (jfs_commit_inode(inode, wait)) {
        jfs_err("jfs_write_inode: jfs_commit_inode failed!");
        return -EIO;
    } else
        return 0;
}

void jfs_evict_inode(struct inode *inode)
{
    jfs_info("In jfs_evict_inode, inode = 0x%p", inode);

    if (!inode->i_nlink && !is_bad_inode(inode)) {
        dquot_initialize(inode);

        if (JFS_IP(inode)->fileset == FILESYSTEM_I) {
            truncate_inode_pages(&inode->i_data, 0);

            if (test_cflag(COMMIT_Freewmap, inode))
                jfs_free_zero_link(inode);

            diFree(inode);

            /*
             * Free the inode from the quota allocation.
             */
            dquot_initialize(inode);
            dquot_free_inode(inode);
        }
    } else {
        truncate_inode_pages(&inode->i_data, 0);
    }
    clear_inode(inode);
    dquot_drop(inode);
}

void jfs_dirty_inode(struct inode *inode, int flags)
{
    static int noisy = 5;

    if (isReadOnly(inode)) {
        if (!special_file(inode->i_mode) && noisy) {
            /* kernel allows writes to devices on read-only
             * partitions and may try to mark inode dirty
             */
            jfs_err("jfs_dirty_inode called on read-only volume");
            jfs_err("Is remount racy?");
            noisy--;
        }
        return;
    }

    set_cflag(COMMIT_Dirty, inode);
}

int jfs_get_block(struct inode *ip, sector_t lblock,
          struct buffer_head *bh_result, int create)
{
    s64 lblock64 = lblock;
    int rc = 0;
    xad_t xad;
    s64 xaddr;
    int xflag;
    s32 xlen = bh_result->b_size >> ip->i_blkbits;

    /*
     * Take appropriate lock on inode
     */
    if (create)
        IWRITE_LOCK(ip, RDWRLOCK_NORMAL);
    else
        IREAD_LOCK(ip, RDWRLOCK_NORMAL);

    if (((lblock64 << ip->i_sb->s_blocksize_bits) < ip->i_size) &&
        (!xtLookup(ip, lblock64, xlen, &xflag, &xaddr, &xlen, 0)) &&
        xaddr) {
        if (xflag & XAD_NOTRECORDED) {
            if (!create)
                /*
                 * Allocated but not recorded, read treats
                 * this as a hole
                 */
                goto unlock;
#ifdef _JFS_4K
            XADoffset(&xad, lblock64);
            XADlength(&xad, xlen);
            XADaddress(&xad, xaddr);
#else               /* _JFS_4K */
            /*
             * As long as block size = 4K, this isn't a problem.
             * We should mark the whole page not ABNR, but how
             * will we know to mark the other blocks BH_New?
             */
            BUG();
#endif              /* _JFS_4K */
            rc = extRecord(ip, &xad);
            if (rc)
                goto unlock;
            set_buffer_new(bh_result);
        }

        map_bh(bh_result, ip->i_sb, xaddr);
        bh_result->b_size = xlen << ip->i_blkbits;
        goto unlock;
    }
    if (!create)
        goto unlock;

    /*
     * Allocate a new block
     */
#ifdef _JFS_4K
    if ((rc = extHint(ip, lblock64 << ip->i_sb->s_blocksize_bits, &xad)))
        goto unlock;
    rc = extAlloc(ip, xlen, lblock64, &xad, false);
    if (rc)
        goto unlock;

    set_buffer_new(bh_result);
    map_bh(bh_result, ip->i_sb, addressXAD(&xad));
    bh_result->b_size = lengthXAD(&xad) << ip->i_blkbits;

#else               /* _JFS_4K */
    /*
     * We need to do whatever it takes to keep all but the last buffers
     * in 4K pages - see jfs_write.c
     */
    BUG();
#endif              /* _JFS_4K */

      unlock:
    /*
     * Release lock on inode
     */
    if (create)
        IWRITE_UNLOCK(ip);
    else
        IREAD_UNLOCK(ip);
    return rc;
}

static int jfs_writepage(struct page *page, struct writeback_control *wbc)
{
    return block_write_full_page(page, jfs_get_block, wbc);
}

static int jfs_writepages(struct address_space *mapping,
            struct writeback_control *wbc)
{
    return mpage_writepages(mapping, wbc, jfs_get_block);
}

static int jfs_readpage(struct file *file, struct page *page)
{
    return mpage_readpage(page, jfs_get_block);
}

static int jfs_readpages(struct file *file, struct address_space *mapping,
        struct list_head *pages, unsigned nr_pages)
{
    return mpage_readpages(mapping, pages, nr_pages, jfs_get_block);
}

static int jfs_write_begin(struct file *file, struct address_space *mapping,
                loff_t pos, unsigned len, unsigned flags,
                struct page **pagep, void **fsdata)
{
    int ret;

    ret = nobh_write_begin(mapping, pos, len, flags, pagep, fsdata,
                jfs_get_block);
    if (unlikely(ret)) {
        loff_t isize = mapping->host->i_size;
        if (pos + len > isize)
            vmtruncate(mapping->host, isize);
    }

    return ret;
}

static sector_t jfs_bmap(struct address_space *mapping, sector_t block)
{
    return generic_block_bmap(mapping, block, jfs_get_block);
}

static ssize_t jfs_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 ret;

    ret = blockdev_direct_IO(rw, iocb, inode, iov, offset, nr_segs,
                 jfs_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) && ret < 0)) {
        loff_t isize = i_size_read(inode);
        loff_t end = offset + iov_length(iov, nr_segs);

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

    return ret;
}

const struct address_space_operations jfs_aops = {
    .readpage   = jfs_readpage,
    .readpages  = jfs_readpages,
    .writepage  = jfs_writepage,
    .writepages = jfs_writepages,
    .write_begin    = jfs_write_begin,
    .write_end  = nobh_write_end,
    .bmap       = jfs_bmap,
    .direct_IO  = jfs_direct_IO,
};

/*
 * Guts of jfs_truncate.  Called with locks already held.  Can be called
 * with directory for truncating directory index table.
 */
void jfs_truncate_nolock(struct inode *ip, loff_t length)
{
    loff_t newsize;
    tid_t tid;

    ASSERT(length >= 0);

    if (test_cflag(COMMIT_Nolink, ip)) {
        xtTruncate(0, ip, length, COMMIT_WMAP);
        return;
    }

    do {
        tid = txBegin(ip->i_sb, 0);

        /*
         * The commit_mutex cannot be taken before txBegin.
         * txBegin may block and there is a chance the inode
         * could be marked dirty and need to be committed
         * before txBegin unblocks
         */
        mutex_lock(&JFS_IP(ip)->commit_mutex);

        newsize = xtTruncate(tid, ip, length,
                     COMMIT_TRUNCATE | COMMIT_PWMAP);
        if (newsize < 0) {
            txEnd(tid);
            mutex_unlock(&JFS_IP(ip)->commit_mutex);
            break;
        }

        ip->i_mtime = ip->i_ctime = CURRENT_TIME;
        mark_inode_dirty(ip);

        txCommit(tid, 1, &ip, 0);
        txEnd(tid);
        mutex_unlock(&JFS_IP(ip)->commit_mutex);
    } while (newsize > length); /* Truncate isn't always atomic */
}

void jfs_truncate(struct inode *ip)
{
    jfs_info("jfs_truncate: size = 0x%lx", (ulong) ip->i_size);

    nobh_truncate_page(ip->i_mapping, ip->i_size, jfs_get_block);

    IWRITE_LOCK(ip, RDWRLOCK_NORMAL);
    jfs_truncate_nolock(ip, ip->i_size);
    IWRITE_UNLOCK(ip);
}