xfs: fix log recovery corruption error due to tail overwrite

[mirror_ubuntu-artful-kernel.git] / fs / xfs / xfs_itable.c

/*
 * Copyright (c) 2000-2002,2005 Silicon Graphics, Inc.
 * All Rights Reserved.
 *
 * 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.
 *
 * This program is distributed in the hope that it would 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 the Free Software Foundation,
 * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */
#include "xfs.h"
#include "xfs_fs.h"
#include "xfs_shared.h"
#include "xfs_format.h"
#include "xfs_log_format.h"
#include "xfs_trans_resv.h"
#include "xfs_mount.h"
#include "xfs_inode.h"
#include "xfs_btree.h"
#include "xfs_ialloc.h"
#include "xfs_ialloc_btree.h"
#include "xfs_itable.h"
#include "xfs_error.h"
#include "xfs_trace.h"
#include "xfs_icache.h"

int
xfs_internal_inum(
        xfs_mount_t     *mp,
        xfs_ino_t       ino)
{
        return (ino == mp->m_sb.sb_rbmino || ino == mp->m_sb.sb_rsumino ||
                (xfs_sb_version_hasquota(&mp->m_sb) &&
                 xfs_is_quota_inode(&mp->m_sb, ino)));
}

/*
 * Return stat information for one inode.
 * Return 0 if ok, else errno.
 */
int
xfs_bulkstat_one_int(
        struct xfs_mount        *mp,            /* mount point for filesystem */
        xfs_ino_t               ino,            /* inode to get data for */
        void __user             *buffer,        /* buffer to place output in */
        int                     ubsize,         /* size of buffer */
        bulkstat_one_fmt_pf     formatter,      /* formatter, copy to user */
        int                     *ubused,        /* bytes used by me */
        int                     *stat)          /* BULKSTAT_RV_... */
{
        struct xfs_icdinode     *dic;           /* dinode core info pointer */
        struct xfs_inode        *ip;            /* incore inode pointer */
        struct inode            *inode;
        struct xfs_bstat        *buf;           /* return buffer */
        int                     error = 0;      /* error value */

        *stat = BULKSTAT_RV_NOTHING;

        if (!buffer || xfs_internal_inum(mp, ino))
                return -EINVAL;

        buf = kmem_zalloc(sizeof(*buf), KM_SLEEP | KM_MAYFAIL);
        if (!buf)
                return -ENOMEM;

        error = xfs_iget(mp, NULL, ino,
                         (XFS_IGET_DONTCACHE | XFS_IGET_UNTRUSTED),
                         XFS_ILOCK_SHARED, &ip);
        if (error)
                goto out_free;

        ASSERT(ip != NULL);
        ASSERT(ip->i_imap.im_blkno != 0);
        inode = VFS_I(ip);

        dic = &ip->i_d;

        /* xfs_iget returns the following without needing
         * further change.
         */
        buf->bs_projid_lo = dic->di_projid_lo;
        buf->bs_projid_hi = dic->di_projid_hi;
        buf->bs_ino = ino;
        buf->bs_uid = dic->di_uid;
        buf->bs_gid = dic->di_gid;
        buf->bs_size = dic->di_size;

        buf->bs_nlink = inode->i_nlink;
        buf->bs_atime.tv_sec = inode->i_atime.tv_sec;
        buf->bs_atime.tv_nsec = inode->i_atime.tv_nsec;
        buf->bs_mtime.tv_sec = inode->i_mtime.tv_sec;
        buf->bs_mtime.tv_nsec = inode->i_mtime.tv_nsec;
        buf->bs_ctime.tv_sec = inode->i_ctime.tv_sec;
        buf->bs_ctime.tv_nsec = inode->i_ctime.tv_nsec;
        buf->bs_gen = inode->i_generation;
        buf->bs_mode = inode->i_mode;

        buf->bs_xflags = xfs_ip2xflags(ip);
        buf->bs_extsize = dic->di_extsize << mp->m_sb.sb_blocklog;
        buf->bs_extents = dic->di_nextents;
        memset(buf->bs_pad, 0, sizeof(buf->bs_pad));
        buf->bs_dmevmask = dic->di_dmevmask;
        buf->bs_dmstate = dic->di_dmstate;
        buf->bs_aextents = dic->di_anextents;
        buf->bs_forkoff = XFS_IFORK_BOFF(ip);

        if (dic->di_version == 3) {
                if (dic->di_flags2 & XFS_DIFLAG2_COWEXTSIZE)
                        buf->bs_cowextsize = dic->di_cowextsize <<
                                        mp->m_sb.sb_blocklog;
        }

        switch (dic->di_format) {
        case XFS_DINODE_FMT_DEV:
                buf->bs_rdev = ip->i_df.if_u2.if_rdev;
                buf->bs_blksize = BLKDEV_IOSIZE;
                buf->bs_blocks = 0;
                break;
        case XFS_DINODE_FMT_LOCAL:
        case XFS_DINODE_FMT_UUID:
                buf->bs_rdev = 0;
                buf->bs_blksize = mp->m_sb.sb_blocksize;
                buf->bs_blocks = 0;
                break;
        case XFS_DINODE_FMT_EXTENTS:
        case XFS_DINODE_FMT_BTREE:
                buf->bs_rdev = 0;
                buf->bs_blksize = mp->m_sb.sb_blocksize;
                buf->bs_blocks = dic->di_nblocks + ip->i_delayed_blks;
                break;
        }
        xfs_iunlock(ip, XFS_ILOCK_SHARED);
        IRELE(ip);

        error = formatter(buffer, ubsize, ubused, buf);
        if (!error)
                *stat = BULKSTAT_RV_DIDONE;

 out_free:
        kmem_free(buf);
        return error;
}

/* Return 0 on success or positive error */
STATIC int
xfs_bulkstat_one_fmt(
        void                    __user *ubuffer,
        int                     ubsize,
        int                     *ubused,
        const xfs_bstat_t       *buffer)
{
        if (ubsize < sizeof(*buffer))
                return -ENOMEM;
        if (copy_to_user(ubuffer, buffer, sizeof(*buffer)))
                return -EFAULT;
        if (ubused)
                *ubused = sizeof(*buffer);
        return 0;
}

int
xfs_bulkstat_one(
        xfs_mount_t     *mp,            /* mount point for filesystem */
        xfs_ino_t       ino,            /* inode number to get data for */
        void            __user *buffer, /* buffer to place output in */
        int             ubsize,         /* size of buffer */
        int             *ubused,        /* bytes used by me */
        int             *stat)          /* BULKSTAT_RV_... */
{
        return xfs_bulkstat_one_int(mp, ino, buffer, ubsize,
                                    xfs_bulkstat_one_fmt, ubused, stat);
}

/*
 * Loop over all clusters in a chunk for a given incore inode allocation btree
 * record.  Do a readahead if there are any allocated inodes in that cluster.
 */
STATIC void
xfs_bulkstat_ichunk_ra(
        struct xfs_mount                *mp,
        xfs_agnumber_t                  agno,
        struct xfs_inobt_rec_incore     *irec)
{
        xfs_agblock_t                   agbno;
        struct blk_plug                 plug;
        int                             blks_per_cluster;
        int                             inodes_per_cluster;
        int                             i;      /* inode chunk index */

        agbno = XFS_AGINO_TO_AGBNO(mp, irec->ir_startino);
        blks_per_cluster = xfs_icluster_size_fsb(mp);
        inodes_per_cluster = blks_per_cluster << mp->m_sb.sb_inopblog;

        blk_start_plug(&plug);
        for (i = 0; i < XFS_INODES_PER_CHUNK;
             i += inodes_per_cluster, agbno += blks_per_cluster) {
                if (xfs_inobt_maskn(i, inodes_per_cluster) & ~irec->ir_free) {
                        xfs_btree_reada_bufs(mp, agno, agbno, blks_per_cluster,
                                             &xfs_inode_buf_ops);
                }
        }
        blk_finish_plug(&plug);
}

/*
 * Lookup the inode chunk that the given inode lives in and then get the record
 * if we found the chunk.  If the inode was not the last in the chunk and there
 * are some left allocated, update the data for the pointed-to record as well as
 * return the count of grabbed inodes.
 */
STATIC int
xfs_bulkstat_grab_ichunk(
        struct xfs_btree_cur            *cur,   /* btree cursor */
        xfs_agino_t                     agino,  /* starting inode of chunk */
        int                             *icount,/* return # of inodes grabbed */
        struct xfs_inobt_rec_incore     *irec)  /* btree record */
{
        int                             idx;    /* index into inode chunk */
        int                             stat;
        int                             error = 0;

        /* Lookup the inode chunk that this inode lives in */
        error = xfs_inobt_lookup(cur, agino, XFS_LOOKUP_LE, &stat);
        if (error)
                return error;
        if (!stat) {
                *icount = 0;
                return error;
        }

        /* Get the record, should always work */
        error = xfs_inobt_get_rec(cur, irec, &stat);
        if (error)
                return error;
        XFS_WANT_CORRUPTED_RETURN(cur->bc_mp, stat == 1);

        /* Check if the record contains the inode in request */
        if (irec->ir_startino + XFS_INODES_PER_CHUNK <= agino) {
                *icount = 0;
                return 0;
        }

        idx = agino - irec->ir_startino + 1;
        if (idx < XFS_INODES_PER_CHUNK &&
            (xfs_inobt_maskn(idx, XFS_INODES_PER_CHUNK - idx) & ~irec->ir_free)) {
                int     i;

                /* We got a right chunk with some left inodes allocated at it.
                 * Grab the chunk record.  Mark all the uninteresting inodes
                 * free -- because they're before our start point.
                 */
                for (i = 0; i < idx; i++) {
                        if (XFS_INOBT_MASK(i) & ~irec->ir_free)
                                irec->ir_freecount++;
                }

                irec->ir_free |= xfs_inobt_maskn(0, idx);
                *icount = irec->ir_count - irec->ir_freecount;
        }

        return 0;
}

#define XFS_BULKSTAT_UBLEFT(ubleft)     ((ubleft) >= statstruct_size)

struct xfs_bulkstat_agichunk {
        char            __user **ac_ubuffer;/* pointer into user's buffer */
        int             ac_ubleft;      /* bytes left in user's buffer */
        int             ac_ubelem;      /* spaces used in user's buffer */
};

/*
 * Process inodes in chunk with a pointer to a formatter function
 * that will iget the inode and fill in the appropriate structure.
 */
static int
xfs_bulkstat_ag_ichunk(
        struct xfs_mount                *mp,
        xfs_agnumber_t                  agno,
        struct xfs_inobt_rec_incore     *irbp,
        bulkstat_one_pf                 formatter,
        size_t                          statstruct_size,
        struct xfs_bulkstat_agichunk    *acp,
        xfs_agino_t                     *last_agino)
{
        char                            __user **ubufp = acp->ac_ubuffer;
        int                             chunkidx;
        int                             error = 0;
        xfs_agino_t                     agino = irbp->ir_startino;

        for (chunkidx = 0; chunkidx < XFS_INODES_PER_CHUNK;
             chunkidx++, agino++) {
                int             fmterror;
                int             ubused;

                /* inode won't fit in buffer, we are done */
                if (acp->ac_ubleft < statstruct_size)
                        break;

                /* Skip if this inode is free */
                if (XFS_INOBT_MASK(chunkidx) & irbp->ir_free)
                        continue;

                /* Get the inode and fill in a single buffer */
                ubused = statstruct_size;
                error = formatter(mp, XFS_AGINO_TO_INO(mp, agno, agino),
                                  *ubufp, acp->ac_ubleft, &ubused, &fmterror);

                if (fmterror == BULKSTAT_RV_GIVEUP ||
                    (error && error != -ENOENT && error != -EINVAL)) {
                        acp->ac_ubleft = 0;
                        ASSERT(error);
                        break;
                }

                /* be careful not to leak error if at end of chunk */
                if (fmterror == BULKSTAT_RV_NOTHING || error) {
                        error = 0;
                        continue;
                }

                *ubufp += ubused;
                acp->ac_ubleft -= ubused;
                acp->ac_ubelem++;
        }

        /*
         * Post-update *last_agino. At this point, agino will always point one
         * inode past the last inode we processed successfully. Hence we
         * substract that inode when setting the *last_agino cursor so that we
         * return the correct cookie to userspace. On the next bulkstat call,
         * the inode under the lastino cookie will be skipped as we have already
         * processed it here.
         */
        *last_agino = agino - 1;

        return error;
}

/*
 * Return stat information in bulk (by-inode) for the filesystem.
 */
int                                     /* error status */
xfs_bulkstat(
        xfs_mount_t             *mp,    /* mount point for filesystem */
        xfs_ino_t               *lastinop, /* last inode returned */
        int                     *ubcountp, /* size of buffer/count returned */
        bulkstat_one_pf         formatter, /* func that'd fill a single buf */
        size_t                  statstruct_size, /* sizeof struct filling */
        char                    __user *ubuffer, /* buffer with inode stats */
        int                     *done)  /* 1 if there are more stats to get */
{
        xfs_buf_t               *agbp;  /* agi header buffer */
        xfs_agino_t             agino;  /* inode # in allocation group */
        xfs_agnumber_t          agno;   /* allocation group number */
        xfs_btree_cur_t         *cur;   /* btree cursor for ialloc btree */
        xfs_inobt_rec_incore_t  *irbuf; /* start of irec buffer */
        int                     nirbuf; /* size of irbuf */
        int                     ubcount; /* size of user's buffer */
        struct xfs_bulkstat_agichunk ac;
        int                     error = 0;

        /*
         * Get the last inode value, see if there's nothing to do.
         */
        agno = XFS_INO_TO_AGNO(mp, *lastinop);
        agino = XFS_INO_TO_AGINO(mp, *lastinop);
        if (agno >= mp->m_sb.sb_agcount ||
            *lastinop != XFS_AGINO_TO_INO(mp, agno, agino)) {
                *done = 1;
                *ubcountp = 0;
                return 0;
        }

        ubcount = *ubcountp; /* statstruct's */
        ac.ac_ubuffer = &ubuffer;
        ac.ac_ubleft = ubcount * statstruct_size; /* bytes */;
        ac.ac_ubelem = 0;

        *ubcountp = 0;
        *done = 0;

        irbuf = kmem_zalloc_large(PAGE_SIZE * 4, KM_SLEEP);
        if (!irbuf)
                return -ENOMEM;
        nirbuf = (PAGE_SIZE * 4) / sizeof(*irbuf);

        /*
         * Loop over the allocation groups, starting from the last
         * inode returned; 0 means start of the allocation group.
         */
        while (agno < mp->m_sb.sb_agcount) {
                struct xfs_inobt_rec_incore     *irbp = irbuf;
                struct xfs_inobt_rec_incore     *irbufend = irbuf + nirbuf;
                bool                            end_of_ag = false;
                int                             icount = 0;
                int                             stat;

                error = xfs_ialloc_read_agi(mp, NULL, agno, &agbp);
                if (error)
                        break;
                /*
                 * Allocate and initialize a btree cursor for ialloc btree.
                 */
                cur = xfs_inobt_init_cursor(mp, NULL, agbp, agno,
                                            XFS_BTNUM_INO);
                if (agino > 0) {
                        /*
                         * In the middle of an allocation group, we need to get
                         * the remainder of the chunk we're in.
                         */
                        struct xfs_inobt_rec_incore     r;

                        error = xfs_bulkstat_grab_ichunk(cur, agino, &icount, &r);
                        if (error)
                                goto del_cursor;
                        if (icount) {
                                irbp->ir_startino = r.ir_startino;
                                irbp->ir_holemask = r.ir_holemask;
                                irbp->ir_count = r.ir_count;
                                irbp->ir_freecount = r.ir_freecount;
                                irbp->ir_free = r.ir_free;
                                irbp++;
                        }
                        /* Increment to the next record */
                        error = xfs_btree_increment(cur, 0, &stat);
                } else {
                        /* Start of ag.  Lookup the first inode chunk */
                        error = xfs_inobt_lookup(cur, 0, XFS_LOOKUP_GE, &stat);
                }
                if (error || stat == 0) {
                        end_of_ag = true;
                        goto del_cursor;
                }

                /*
                 * Loop through inode btree records in this ag,
                 * until we run out of inodes or space in the buffer.
                 */
                while (irbp < irbufend && icount < ubcount) {
                        struct xfs_inobt_rec_incore     r;

                        error = xfs_inobt_get_rec(cur, &r, &stat);
                        if (error || stat == 0) {
                                end_of_ag = true;
                                goto del_cursor;
                        }

                        /*
                         * If this chunk has any allocated inodes, save it.
                         * Also start read-ahead now for this chunk.
                         */
                        if (r.ir_freecount < r.ir_count) {
                                xfs_bulkstat_ichunk_ra(mp, agno, &r);
                                irbp->ir_startino = r.ir_startino;
                                irbp->ir_holemask = r.ir_holemask;
                                irbp->ir_count = r.ir_count;
                                irbp->ir_freecount = r.ir_freecount;
                                irbp->ir_free = r.ir_free;
                                irbp++;
                                icount += r.ir_count - r.ir_freecount;
                        }
                        error = xfs_btree_increment(cur, 0, &stat);
                        if (error || stat == 0) {
                                end_of_ag = true;
                                goto del_cursor;
                        }
                        cond_resched();
                }

                /*
                 * Drop the btree buffers and the agi buffer as we can't hold any
                 * of the locks these represent when calling iget. If there is a
                 * pending error, then we are done.
                 */
del_cursor:
                xfs_btree_del_cursor(cur, error ?
                                          XFS_BTREE_ERROR : XFS_BTREE_NOERROR);
                xfs_buf_relse(agbp);
                if (error)
                        break;
                /*
                 * Now format all the good inodes into the user's buffer. The
                 * call to xfs_bulkstat_ag_ichunk() sets up the agino pointer
                 * for the next loop iteration.
                 */
                irbufend = irbp;
                for (irbp = irbuf;
                     irbp < irbufend && ac.ac_ubleft >= statstruct_size;
                     irbp++) {
                        error = xfs_bulkstat_ag_ichunk(mp, agno, irbp,
                                        formatter, statstruct_size, &ac,
                                        &agino);
                        if (error)
                                break;

                        cond_resched();
                }

                /*
                 * If we've run out of space or had a formatting error, we
                 * are now done
                 */
                if (ac.ac_ubleft < statstruct_size || error)
                        break;

                if (end_of_ag) {
                        agno++;
                        agino = 0;
                }
        }
        /*
         * Done, we're either out of filesystem or space to put the data.
         */
        kmem_free(irbuf);
        *ubcountp = ac.ac_ubelem;

        /*
         * We found some inodes, so clear the error status and return them.
         * The lastino pointer will point directly at the inode that triggered
         * any error that occurred, so on the next call the error will be
         * triggered again and propagated to userspace as there will be no
         * formatted inodes in the buffer.
         */
        if (ac.ac_ubelem)
                error = 0;

        /*
         * If we ran out of filesystem, lastino will point off the end of
         * the filesystem so the next call will return immediately.
         */
        *lastinop = XFS_AGINO_TO_INO(mp, agno, agino);
        if (agno >= mp->m_sb.sb_agcount)
                *done = 1;

        return error;
}

int
xfs_inumbers_fmt(
        void                    __user *ubuffer, /* buffer to write to */
        const struct xfs_inogrp *buffer,        /* buffer to read from */
        long                    count,          /* # of elements to read */
        long                    *written)       /* # of bytes written */
{
        if (copy_to_user(ubuffer, buffer, count * sizeof(*buffer)))
                return -EFAULT;
        *written = count * sizeof(*buffer);
        return 0;
}

/*
 * Return inode number table for the filesystem.
 */
int                                     /* error status */
xfs_inumbers(
        struct xfs_mount        *mp,/* mount point for filesystem */
        xfs_ino_t               *lastino,/* last inode returned */
        int                     *count,/* size of buffer/count returned */
        void                    __user *ubuffer,/* buffer with inode descriptions */
        inumbers_fmt_pf         formatter)
{
        xfs_agnumber_t          agno = XFS_INO_TO_AGNO(mp, *lastino);
        xfs_agino_t             agino = XFS_INO_TO_AGINO(mp, *lastino);
        struct xfs_btree_cur    *cur = NULL;
        struct xfs_buf          *agbp = NULL;
        struct xfs_inogrp       *buffer;
        int                     bcount;
        int                     left = *count;
        int                     bufidx = 0;
        int                     error = 0;

        *count = 0;
        if (agno >= mp->m_sb.sb_agcount ||
            *lastino != XFS_AGINO_TO_INO(mp, agno, agino))
                return error;

        bcount = MIN(left, (int)(PAGE_SIZE / sizeof(*buffer)));
        buffer = kmem_zalloc(bcount * sizeof(*buffer), KM_SLEEP);
        do {
                struct xfs_inobt_rec_incore     r;
                int                             stat;

                if (!agbp) {
                        error = xfs_ialloc_read_agi(mp, NULL, agno, &agbp);
                        if (error)
                                break;

                        cur = xfs_inobt_init_cursor(mp, NULL, agbp, agno,
                                                    XFS_BTNUM_INO);
                        error = xfs_inobt_lookup(cur, agino, XFS_LOOKUP_GE,
                                                 &stat);
                        if (error)
                                break;
                        if (!stat)
                                goto next_ag;
                }

                error = xfs_inobt_get_rec(cur, &r, &stat);
                if (error)
                        break;
                if (!stat)
                        goto next_ag;

                agino = r.ir_startino + XFS_INODES_PER_CHUNK - 1;
                buffer[bufidx].xi_startino =
                        XFS_AGINO_TO_INO(mp, agno, r.ir_startino);
                buffer[bufidx].xi_alloccount = r.ir_count - r.ir_freecount;
                buffer[bufidx].xi_allocmask = ~r.ir_free;
                if (++bufidx == bcount) {
                        long    written;

                        error = formatter(ubuffer, buffer, bufidx, &written);
                        if (error)
                                break;
                        ubuffer += written;
                        *count += bufidx;
                        bufidx = 0;
                }
                if (!--left)
                        break;

                error = xfs_btree_increment(cur, 0, &stat);
                if (error)
                        break;
                if (stat)
                        continue;

next_ag:
                xfs_btree_del_cursor(cur, XFS_BTREE_ERROR);
                cur = NULL;
                xfs_buf_relse(agbp);
                agbp = NULL;
                agino = 0;
                agno++;
        } while (agno < mp->m_sb.sb_agcount);

        if (!error) {
                if (bufidx) {
                        long    written;

                        error = formatter(ubuffer, buffer, bufidx, &written);
                        if (!error)
                                *count += bufidx;
                }
                *lastino = XFS_AGINO_TO_INO(mp, agno, agino);
        }

        kmem_free(buffer);
        if (cur)
                xfs_btree_del_cursor(cur, (error ? XFS_BTREE_ERROR :
                                           XFS_BTREE_NOERROR));
        if (agbp)
                xfs_buf_relse(agbp);

        return error;
}