Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris...

[linux-2.6/mini2440.git] / fs / gfs2 / ops_super.c

/*
 * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.
 * Copyright (C) 2004-2008 Red Hat, Inc.  All rights reserved.
 *
 * This copyrighted material is made available to anyone wishing to use,
 * modify, copy, or redistribute it subject to the terms and conditions
 * of the GNU General Public License version 2.
 */

#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/completion.h>
#include <linux/buffer_head.h>
#include <linux/statfs.h>
#include <linux/seq_file.h>
#include <linux/mount.h>
#include <linux/kthread.h>
#include <linux/delay.h>
#include <linux/gfs2_ondisk.h>
#include <linux/crc32.h>
#include <linux/lm_interface.h>
#include <linux/time.h>

#include "gfs2.h"
#include "incore.h"
#include "glock.h"
#include "inode.h"
#include "log.h"
#include "mount.h"
#include "quota.h"
#include "recovery.h"
#include "rgrp.h"
#include "super.h"
#include "sys.h"
#include "util.h"
#include "trans.h"
#include "dir.h"
#include "eattr.h"
#include "bmap.h"
#include "meta_io.h"

/**
 * gfs2_write_inode - Make sure the inode is stable on the disk
 * @inode: The inode
 * @sync: synchronous write flag
 *
 * Returns: errno
 */

static int gfs2_write_inode(struct inode *inode, int sync)
{
        struct gfs2_inode *ip = GFS2_I(inode);
        struct gfs2_sbd *sdp = GFS2_SB(inode);
        struct gfs2_holder gh;
        struct buffer_head *bh;
        struct timespec atime;
        struct gfs2_dinode *di;
        int ret = 0;

        /* Check this is a "normal" inode, etc */
        if (!test_bit(GIF_USER, &ip->i_flags) ||
            (current->flags & PF_MEMALLOC))
                return 0;
        ret = gfs2_glock_nq_init(ip->i_gl, LM_ST_EXCLUSIVE, 0, &gh);
        if (ret)
                goto do_flush;
        ret = gfs2_trans_begin(sdp, RES_DINODE, 0);
        if (ret)
                goto do_unlock;
        ret = gfs2_meta_inode_buffer(ip, &bh);
        if (ret == 0) {
                di = (struct gfs2_dinode *)bh->b_data;
                atime.tv_sec = be64_to_cpu(di->di_atime);
                atime.tv_nsec = be32_to_cpu(di->di_atime_nsec);
                if (timespec_compare(&inode->i_atime, &atime) > 0) {
                        gfs2_trans_add_bh(ip->i_gl, bh, 1);
                        gfs2_dinode_out(ip, bh->b_data);
                }
                brelse(bh);
        }
        gfs2_trans_end(sdp);
do_unlock:
        gfs2_glock_dq_uninit(&gh);
do_flush:
        if (sync != 0)
                gfs2_log_flush(GFS2_SB(inode), ip->i_gl);
        return ret;
}

/**
 * gfs2_make_fs_ro - Turn a Read-Write FS into a Read-Only one
 * @sdp: the filesystem
 *
 * Returns: errno
 */

static int gfs2_make_fs_ro(struct gfs2_sbd *sdp)
{
        struct gfs2_holder t_gh;
        int error;

        gfs2_quota_sync(sdp);
        gfs2_statfs_sync(sdp);

        error = gfs2_glock_nq_init(sdp->sd_trans_gl, LM_ST_SHARED, GL_NOCACHE,
                                   &t_gh);
        if (error && !test_bit(SDF_SHUTDOWN, &sdp->sd_flags))
                return error;

        gfs2_meta_syncfs(sdp);
        gfs2_log_shutdown(sdp);

        clear_bit(SDF_JOURNAL_LIVE, &sdp->sd_flags);

        if (t_gh.gh_gl)
                gfs2_glock_dq_uninit(&t_gh);

        gfs2_quota_cleanup(sdp);

        return error;
}

/**
 * gfs2_put_super - Unmount the filesystem
 * @sb: The VFS superblock
 *
 */

static void gfs2_put_super(struct super_block *sb)
{
        struct gfs2_sbd *sdp = sb->s_fs_info;
        int error;

        /*  Unfreeze the filesystem, if we need to  */

        mutex_lock(&sdp->sd_freeze_lock);
        if (sdp->sd_freeze_count)
                gfs2_glock_dq_uninit(&sdp->sd_freeze_gh);
        mutex_unlock(&sdp->sd_freeze_lock);

        kthread_stop(sdp->sd_quotad_process);
        kthread_stop(sdp->sd_logd_process);
        kthread_stop(sdp->sd_recoverd_process);

        if (!(sb->s_flags & MS_RDONLY)) {
                error = gfs2_make_fs_ro(sdp);
                if (error)
                        gfs2_io_error(sdp);
        }
        /*  At this point, we're through modifying the disk  */

        /*  Release stuff  */

        iput(sdp->sd_jindex);
        iput(sdp->sd_inum_inode);
        iput(sdp->sd_statfs_inode);
        iput(sdp->sd_rindex);
        iput(sdp->sd_quota_inode);

        gfs2_glock_put(sdp->sd_rename_gl);
        gfs2_glock_put(sdp->sd_trans_gl);

        if (!sdp->sd_args.ar_spectator) {
                gfs2_glock_dq_uninit(&sdp->sd_journal_gh);
                gfs2_glock_dq_uninit(&sdp->sd_jinode_gh);
                gfs2_glock_dq_uninit(&sdp->sd_ir_gh);
                gfs2_glock_dq_uninit(&sdp->sd_sc_gh);
                gfs2_glock_dq_uninit(&sdp->sd_qc_gh);
                iput(sdp->sd_ir_inode);
                iput(sdp->sd_sc_inode);
                iput(sdp->sd_qc_inode);
        }

        gfs2_glock_dq_uninit(&sdp->sd_live_gh);
        gfs2_clear_rgrpd(sdp);
        gfs2_jindex_free(sdp);
        /*  Take apart glock structures and buffer lists  */
        gfs2_gl_hash_clear(sdp);
        /*  Unmount the locking protocol  */
        gfs2_lm_unmount(sdp);

        /*  At this point, we're through participating in the lockspace  */
        gfs2_sys_fs_del(sdp);
}

/**
 * gfs2_write_super
 * @sb: the superblock
 *
 */

static void gfs2_write_super(struct super_block *sb)
{
        sb->s_dirt = 0;
}

/**
 * gfs2_sync_fs - sync the filesystem
 * @sb: the superblock
 *
 * Flushes the log to disk.
 */

static int gfs2_sync_fs(struct super_block *sb, int wait)
{
        sb->s_dirt = 0;
        if (wait && sb->s_fs_info)
                gfs2_log_flush(sb->s_fs_info, NULL);
        return 0;
}

/**
 * gfs2_freeze - prevent further writes to the filesystem
 * @sb: the VFS structure for the filesystem
 *
 */

static int gfs2_freeze(struct super_block *sb)
{
        struct gfs2_sbd *sdp = sb->s_fs_info;
        int error;

        if (test_bit(SDF_SHUTDOWN, &sdp->sd_flags))
                return -EINVAL;

        for (;;) {
                error = gfs2_freeze_fs(sdp);
                if (!error)
                        break;

                switch (error) {
                case -EBUSY:
                        fs_err(sdp, "waiting for recovery before freeze\n");
                        break;

                default:
                        fs_err(sdp, "error freezing FS: %d\n", error);
                        break;
                }

                fs_err(sdp, "retrying...\n");
                msleep(1000);
        }
        return 0;
}

/**
 * gfs2_unfreeze - reallow writes to the filesystem
 * @sb: the VFS structure for the filesystem
 *
 */

static int gfs2_unfreeze(struct super_block *sb)
{
        gfs2_unfreeze_fs(sb->s_fs_info);
        return 0;
}

/**
 * statfs_fill - fill in the sg for a given RG
 * @rgd: the RG
 * @sc: the sc structure
 *
 * Returns: 0 on success, -ESTALE if the LVB is invalid
 */

static int statfs_slow_fill(struct gfs2_rgrpd *rgd,
                            struct gfs2_statfs_change_host *sc)
{
        gfs2_rgrp_verify(rgd);
        sc->sc_total += rgd->rd_data;
        sc->sc_free += rgd->rd_free;
        sc->sc_dinodes += rgd->rd_dinodes;
        return 0;
}

/**
 * gfs2_statfs_slow - Stat a filesystem using asynchronous locking
 * @sdp: the filesystem
 * @sc: the sc info that will be returned
 *
 * Any error (other than a signal) will cause this routine to fall back
 * to the synchronous version.
 *
 * FIXME: This really shouldn't busy wait like this.
 *
 * Returns: errno
 */

static int gfs2_statfs_slow(struct gfs2_sbd *sdp, struct gfs2_statfs_change_host *sc)
{
        struct gfs2_holder ri_gh;
        struct gfs2_rgrpd *rgd_next;
        struct gfs2_holder *gha, *gh;
        unsigned int slots = 64;
        unsigned int x;
        int done;
        int error = 0, err;

        memset(sc, 0, sizeof(struct gfs2_statfs_change_host));
        gha = kcalloc(slots, sizeof(struct gfs2_holder), GFP_KERNEL);
        if (!gha)
                return -ENOMEM;

        error = gfs2_rindex_hold(sdp, &ri_gh);
        if (error)
                goto out;

        rgd_next = gfs2_rgrpd_get_first(sdp);

        for (;;) {
                done = 1;

                for (x = 0; x < slots; x++) {
                        gh = gha + x;

                        if (gh->gh_gl && gfs2_glock_poll(gh)) {
                                err = gfs2_glock_wait(gh);
                                if (err) {
                                        gfs2_holder_uninit(gh);
                                        error = err;
                                } else {
                                        if (!error)
                                                error = statfs_slow_fill(
                                                        gh->gh_gl->gl_object, sc);
                                        gfs2_glock_dq_uninit(gh);
                                }
                        }

                        if (gh->gh_gl)
                                done = 0;
                        else if (rgd_next && !error) {
                                error = gfs2_glock_nq_init(rgd_next->rd_gl,
                                                           LM_ST_SHARED,
                                                           GL_ASYNC,
                                                           gh);
                                rgd_next = gfs2_rgrpd_get_next(rgd_next);
                                done = 0;
                        }

                        if (signal_pending(current))
                                error = -ERESTARTSYS;
                }

                if (done)
                        break;

                yield();
        }

        gfs2_glock_dq_uninit(&ri_gh);

out:
        kfree(gha);
        return error;
}

/**
 * gfs2_statfs_i - Do a statfs
 * @sdp: the filesystem
 * @sg: the sg structure
 *
 * Returns: errno
 */

static int gfs2_statfs_i(struct gfs2_sbd *sdp, struct gfs2_statfs_change_host *sc)
{
        struct gfs2_statfs_change_host *m_sc = &sdp->sd_statfs_master;
        struct gfs2_statfs_change_host *l_sc = &sdp->sd_statfs_local;

        spin_lock(&sdp->sd_statfs_spin);

        *sc = *m_sc;
        sc->sc_total += l_sc->sc_total;
        sc->sc_free += l_sc->sc_free;
        sc->sc_dinodes += l_sc->sc_dinodes;

        spin_unlock(&sdp->sd_statfs_spin);

        if (sc->sc_free < 0)
                sc->sc_free = 0;
        if (sc->sc_free > sc->sc_total)
                sc->sc_free = sc->sc_total;
        if (sc->sc_dinodes < 0)
                sc->sc_dinodes = 0;

        return 0;
}

/**
 * gfs2_statfs - Gather and return stats about the filesystem
 * @sb: The superblock
 * @statfsbuf: The buffer
 *
 * Returns: 0 on success or error code
 */

static int gfs2_statfs(struct dentry *dentry, struct kstatfs *buf)
{
        struct super_block *sb = dentry->d_inode->i_sb;
        struct gfs2_sbd *sdp = sb->s_fs_info;
        struct gfs2_statfs_change_host sc;
        int error;

        if (gfs2_tune_get(sdp, gt_statfs_slow))
                error = gfs2_statfs_slow(sdp, &sc);
        else
                error = gfs2_statfs_i(sdp, &sc);

        if (error)
                return error;

        buf->f_type = GFS2_MAGIC;
        buf->f_bsize = sdp->sd_sb.sb_bsize;
        buf->f_blocks = sc.sc_total;
        buf->f_bfree = sc.sc_free;
        buf->f_bavail = sc.sc_free;
        buf->f_files = sc.sc_dinodes + sc.sc_free;
        buf->f_ffree = sc.sc_free;
        buf->f_namelen = GFS2_FNAMESIZE;

        return 0;
}

/**
 * gfs2_remount_fs - called when the FS is remounted
 * @sb:  the filesystem
 * @flags:  the remount flags
 * @data:  extra data passed in (not used right now)
 *
 * Returns: errno
 */

static int gfs2_remount_fs(struct super_block *sb, int *flags, char *data)
{
        struct gfs2_sbd *sdp = sb->s_fs_info;
        int error;

        error = gfs2_mount_args(sdp, data, 1);
        if (error)
                return error;

        if (sdp->sd_args.ar_spectator)
                *flags |= MS_RDONLY;
        else {
                if (*flags & MS_RDONLY) {
                        if (!(sb->s_flags & MS_RDONLY))
                                error = gfs2_make_fs_ro(sdp);
                } else if (!(*flags & MS_RDONLY) &&
                           (sb->s_flags & MS_RDONLY)) {
                        error = gfs2_make_fs_rw(sdp);
                }
        }

        return error;
}

/**
 * gfs2_drop_inode - Drop an inode (test for remote unlink)
 * @inode: The inode to drop
 *
 * If we've received a callback on an iopen lock then its because a
 * remote node tried to deallocate the inode but failed due to this node
 * still having the inode open. Here we mark the link count zero
 * since we know that it must have reached zero if the GLF_DEMOTE flag
 * is set on the iopen glock. If we didn't do a disk read since the
 * remote node removed the final link then we might otherwise miss
 * this event. This check ensures that this node will deallocate the
 * inode's blocks, or alternatively pass the baton on to another
 * node for later deallocation.
 */

static void gfs2_drop_inode(struct inode *inode)
{
        struct gfs2_inode *ip = GFS2_I(inode);

        if (test_bit(GIF_USER, &ip->i_flags) && inode->i_nlink) {
                struct gfs2_glock *gl = ip->i_iopen_gh.gh_gl;
                if (gl && test_bit(GLF_DEMOTE, &gl->gl_flags))
                        clear_nlink(inode);
        }
        generic_drop_inode(inode);
}

/**
 * gfs2_clear_inode - Deallocate an inode when VFS is done with it
 * @inode: The VFS inode
 *
 */

static void gfs2_clear_inode(struct inode *inode)
{
        struct gfs2_inode *ip = GFS2_I(inode);

        /* This tells us its a "real" inode and not one which only
         * serves to contain an address space (see rgrp.c, meta_io.c)
         * which therefore doesn't have its own glocks.
         */
        if (test_bit(GIF_USER, &ip->i_flags)) {
                ip->i_gl->gl_object = NULL;
                gfs2_glock_put(ip->i_gl);
                ip->i_gl = NULL;
                if (ip->i_iopen_gh.gh_gl) {
                        ip->i_iopen_gh.gh_gl->gl_object = NULL;
                        gfs2_glock_dq_uninit(&ip->i_iopen_gh);
                }
        }
}

static int is_ancestor(const struct dentry *d1, const struct dentry *d2)
{
        do {
                if (d1 == d2)
                        return 1;
                d1 = d1->d_parent;
        } while (!IS_ROOT(d1));
        return 0;
}

/**
 * gfs2_show_options - Show mount options for /proc/mounts
 * @s: seq_file structure
 * @mnt: vfsmount
 *
 * Returns: 0 on success or error code
 */

static int gfs2_show_options(struct seq_file *s, struct vfsmount *mnt)
{
        struct gfs2_sbd *sdp = mnt->mnt_sb->s_fs_info;
        struct gfs2_args *args = &sdp->sd_args;

        if (is_ancestor(mnt->mnt_root, sdp->sd_master_dir))
                seq_printf(s, ",meta");
        if (args->ar_lockproto[0])
                seq_printf(s, ",lockproto=%s", args->ar_lockproto);
        if (args->ar_locktable[0])
                seq_printf(s, ",locktable=%s", args->ar_locktable);
        if (args->ar_hostdata[0])
                seq_printf(s, ",hostdata=%s", args->ar_hostdata);
        if (args->ar_spectator)
                seq_printf(s, ",spectator");
        if (args->ar_ignore_local_fs)
                seq_printf(s, ",ignore_local_fs");
        if (args->ar_localflocks)
                seq_printf(s, ",localflocks");
        if (args->ar_localcaching)
                seq_printf(s, ",localcaching");
        if (args->ar_debug)
                seq_printf(s, ",debug");
        if (args->ar_upgrade)
                seq_printf(s, ",upgrade");
        if (args->ar_posix_acl)
                seq_printf(s, ",acl");
        if (args->ar_quota != GFS2_QUOTA_DEFAULT) {
                char *state;
                switch (args->ar_quota) {
                case GFS2_QUOTA_OFF:
                        state = "off";
                        break;
                case GFS2_QUOTA_ACCOUNT:
                        state = "account";
                        break;
                case GFS2_QUOTA_ON:
                        state = "on";
                        break;
                default:
                        state = "unknown";
                        break;
                }
                seq_printf(s, ",quota=%s", state);
        }
        if (args->ar_suiddir)
                seq_printf(s, ",suiddir");
        if (args->ar_data != GFS2_DATA_DEFAULT) {
                char *state;
                switch (args->ar_data) {
                case GFS2_DATA_WRITEBACK:
                        state = "writeback";
                        break;
                case GFS2_DATA_ORDERED:
                        state = "ordered";
                        break;
                default:
                        state = "unknown";
                        break;
                }
                seq_printf(s, ",data=%s", state);
        }

        return 0;
}

/*
 * We have to (at the moment) hold the inodes main lock to cover
 * the gap between unlocking the shared lock on the iopen lock and
 * taking the exclusive lock. I'd rather do a shared -> exclusive
 * conversion on the iopen lock, but we can change that later. This
 * is safe, just less efficient.
 */

static void gfs2_delete_inode(struct inode *inode)
{
        struct gfs2_sbd *sdp = inode->i_sb->s_fs_info;
        struct gfs2_inode *ip = GFS2_I(inode);
        struct gfs2_holder gh;
        int error;

        if (!test_bit(GIF_USER, &ip->i_flags))
                goto out;

        error = gfs2_glock_nq_init(ip->i_gl, LM_ST_EXCLUSIVE, 0, &gh);
        if (unlikely(error)) {
                gfs2_glock_dq_uninit(&ip->i_iopen_gh);
                goto out;
        }

        gfs2_glock_dq_wait(&ip->i_iopen_gh);
        gfs2_holder_reinit(LM_ST_EXCLUSIVE, LM_FLAG_TRY_1CB | GL_NOCACHE, &ip->i_iopen_gh);
        error = gfs2_glock_nq(&ip->i_iopen_gh);
        if (error)
                goto out_truncate;

        if (S_ISDIR(inode->i_mode) &&
            (ip->i_diskflags & GFS2_DIF_EXHASH)) {
                error = gfs2_dir_exhash_dealloc(ip);
                if (error)
                        goto out_unlock;
        }

        if (ip->i_eattr) {
                error = gfs2_ea_dealloc(ip);
                if (error)
                        goto out_unlock;
        }

        if (!gfs2_is_stuffed(ip)) {
                error = gfs2_file_dealloc(ip);
                if (error)
                        goto out_unlock;
        }

        error = gfs2_dinode_dealloc(ip);
        if (error)
                goto out_unlock;

out_truncate:
        error = gfs2_trans_begin(sdp, 0, sdp->sd_jdesc->jd_blocks);
        if (error)
                goto out_unlock;
        /* Needs to be done before glock release & also in a transaction */
        truncate_inode_pages(&inode->i_data, 0);
        gfs2_trans_end(sdp);

out_unlock:
        if (test_bit(HIF_HOLDER, &ip->i_iopen_gh.gh_iflags))
                gfs2_glock_dq(&ip->i_iopen_gh);
        gfs2_holder_uninit(&ip->i_iopen_gh);
        gfs2_glock_dq_uninit(&gh);
        if (error && error != GLR_TRYFAILED)
                fs_warn(sdp, "gfs2_delete_inode: %d\n", error);
out:
        truncate_inode_pages(&inode->i_data, 0);
        clear_inode(inode);
}

static struct inode *gfs2_alloc_inode(struct super_block *sb)
{
        struct gfs2_inode *ip;

        ip = kmem_cache_alloc(gfs2_inode_cachep, GFP_KERNEL);
        if (ip) {
                ip->i_flags = 0;
                ip->i_gl = NULL;
        }
        return &ip->i_inode;
}

static void gfs2_destroy_inode(struct inode *inode)
{
        kmem_cache_free(gfs2_inode_cachep, inode);
}

const struct super_operations gfs2_super_ops = {
        .alloc_inode            = gfs2_alloc_inode,
        .destroy_inode          = gfs2_destroy_inode,
        .write_inode            = gfs2_write_inode,
        .delete_inode           = gfs2_delete_inode,
        .put_super              = gfs2_put_super,
        .write_super            = gfs2_write_super,
        .sync_fs                = gfs2_sync_fs,
        .freeze_fs              = gfs2_freeze,
        .unfreeze_fs            = gfs2_unfreeze,
        .statfs                 = gfs2_statfs,
        .remount_fs             = gfs2_remount_fs,
        .clear_inode            = gfs2_clear_inode,
        .drop_inode             = gfs2_drop_inode,
        .show_options           = gfs2_show_options,
};