// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (c) 2000-2003,2005 Silicon Graphics, Inc.
 * All Rights Reserved.
 */
#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_trans.h"
#include "xfs_dir2.h"
#include "xfs_dir2_priv.h"
#include "xfs_trace.h"

/*
 * Prototypes for internal functions.
 */
static void xfs_dir2_sf_addname_easy(xfs_da_args_t *args,
                                     xfs_dir2_sf_entry_t *sfep,
                                     xfs_dir2_data_aoff_t offset,
                                     int new_isize);
static void xfs_dir2_sf_addname_hard(xfs_da_args_t *args, int objchange,
                                     int new_isize);
static int xfs_dir2_sf_addname_pick(xfs_da_args_t *args, int objchange,
                                    xfs_dir2_sf_entry_t **sfepp,
                                    xfs_dir2_data_aoff_t *offsetp);
#ifdef DEBUG
static void xfs_dir2_sf_check(xfs_da_args_t *args);
#else
#define xfs_dir2_sf_check(args)
#endif /* DEBUG */

static void xfs_dir2_sf_toino4(xfs_da_args_t *args);
static void xfs_dir2_sf_toino8(xfs_da_args_t *args);

/*
 * Given a block directory (dp/block), calculate its size as a shortform (sf)
 * directory and a header for the sf directory, if it will fit it the
 * space currently present in the inode.  If it won't fit, the output
 * size is too big (but not accurate).
 */
int                                             /* size for sf form */
xfs_dir2_block_sfsize(
        xfs_inode_t             *dp,            /* incore inode pointer */
        xfs_dir2_data_hdr_t     *hdr,           /* block directory data */
        xfs_dir2_sf_hdr_t       *sfhp)          /* output: header for sf form */
{
        xfs_dir2_dataptr_t      addr;           /* data entry address */
        xfs_dir2_leaf_entry_t   *blp;           /* leaf area of the block */
        xfs_dir2_block_tail_t   *btp;           /* tail area of the block */
        int                     count;          /* shortform entry count */
        xfs_dir2_data_entry_t   *dep;           /* data entry in the block */
        int                     i;              /* block entry index */
        int                     i8count;        /* count of big-inode entries */
        int                     isdot;          /* entry is "." */
        int                     isdotdot;       /* entry is ".." */
        xfs_mount_t             *mp;            /* mount structure pointer */
        int                     namelen;        /* total name bytes */
        xfs_ino_t               parent = 0;     /* parent inode number */
        int                     size=0;         /* total computed size */
        int                     has_ftype;
        struct xfs_da_geometry  *geo;

        mp = dp->i_mount;
        geo = mp->m_dir_geo;

        /*
         * if there is a filetype field, add the extra byte to the namelen
         * for each entry that we see.
         */
        has_ftype = xfs_sb_version_hasftype(&mp->m_sb) ? 1 : 0;

        count = i8count = namelen = 0;
        btp = xfs_dir2_block_tail_p(geo, hdr);
        blp = xfs_dir2_block_leaf_p(btp);

        /*
         * Iterate over the block's data entries by using the leaf pointers.
         */
        for (i = 0; i < be32_to_cpu(btp->count); i++) {
                if ((addr = be32_to_cpu(blp[i].address)) == XFS_DIR2_NULL_DATAPTR)
                        continue;
                /*
                 * Calculate the pointer to the entry at hand.
                 */
                dep = (xfs_dir2_data_entry_t *)((char *)hdr +
                                xfs_dir2_dataptr_to_off(geo, addr));
                /*
                 * Detect . and .., so we can special-case them.
                 * . is not included in sf directories.
                 * .. is included by just the parent inode number.
                 */
                isdot = dep->namelen == 1 && dep->name[0] == '.';
                isdotdot =
                        dep->namelen == 2 &&
                        dep->name[0] == '.' && dep->name[1] == '.';

                if (!isdot)
                        i8count += be64_to_cpu(dep->inumber) > XFS_DIR2_MAX_SHORT_INUM;

                /* take into account the file type field */
                if (!isdot && !isdotdot) {
                        count++;
                        namelen += dep->namelen + has_ftype;
                } else if (isdotdot)
                        parent = be64_to_cpu(dep->inumber);
                /*
                 * Calculate the new size, see if we should give up yet.
                 */
                size = xfs_dir2_sf_hdr_size(i8count) +  /* header */
                       count * 3 * sizeof(u8) +         /* namelen + offset */
                       namelen +                        /* name */
                       (i8count ?                       /* inumber */
                                count * XFS_INO64_SIZE :
                                count * XFS_INO32_SIZE);
                if (size > XFS_IFORK_DSIZE(dp))
                        return size;            /* size value is a failure */
        }
        /*
         * Create the output header, if it worked.
         */
        sfhp->count = count;
        sfhp->i8count = i8count;
        dp->d_ops->sf_put_parent_ino(sfhp, parent);
        return size;
}

/*
 * Convert a block format directory to shortform.
 * Caller has already checked that it will fit, and built us a header.
 */
int                                             /* error */
xfs_dir2_block_to_sf(
        xfs_da_args_t           *args,          /* operation arguments */
        struct xfs_buf          *bp,
        int                     size,           /* shortform directory size */
        xfs_dir2_sf_hdr_t       *sfhp)          /* shortform directory hdr */
{
        xfs_dir2_data_hdr_t     *hdr;           /* block header */
        xfs_dir2_data_entry_t   *dep;           /* data entry pointer */
        xfs_inode_t             *dp;            /* incore directory inode */
        xfs_dir2_data_unused_t  *dup;           /* unused data pointer */
        char                    *endptr;        /* end of data entries */
        int                     error;          /* error return value */
        int                     logflags;       /* inode logging flags */
        xfs_mount_t             *mp;            /* filesystem mount point */
        char                    *ptr;           /* current data pointer */
        xfs_dir2_sf_entry_t     *sfep;          /* shortform entry */
        xfs_dir2_sf_hdr_t       *sfp;           /* shortform directory header */
        xfs_dir2_sf_hdr_t       *dst;           /* temporary data buffer */

        trace_xfs_dir2_block_to_sf(args);

        dp = args->dp;
        mp = dp->i_mount;

        /*
         * allocate a temporary destination buffer the size of the inode
         * to format the data into. Once we have formatted the data, we
         * can free the block and copy the formatted data into the inode literal
         * area.
         */
        dst = kmem_alloc(mp->m_sb.sb_inodesize, 0);
        hdr = bp->b_addr;

        /*
         * Copy the header into the newly allocate local space.
         */
        sfp = (xfs_dir2_sf_hdr_t *)dst;
        memcpy(sfp, sfhp, xfs_dir2_sf_hdr_size(sfhp->i8count));

        /*
         * Set up to loop over the block's entries.
         */
        ptr = (char *)dp->d_ops->data_entry_p(hdr);
        endptr = xfs_dir3_data_endp(args->geo, hdr);
        sfep = xfs_dir2_sf_firstentry(sfp);
        /*
         * Loop over the active and unused entries.
         * Stop when we reach the leaf/tail portion of the block.
         */
        while (ptr < endptr) {
                /*
                 * If it's unused, just skip over it.
                 */
                dup = (xfs_dir2_data_unused_t *)ptr;
                if (be16_to_cpu(dup->freetag) == XFS_DIR2_DATA_FREE_TAG) {
                        ptr += be16_to_cpu(dup->length);
                        continue;
                }
                dep = (xfs_dir2_data_entry_t *)ptr;
                /*
                 * Skip .
                 */
                if (dep->namelen == 1 && dep->name[0] == '.')
                        ASSERT(be64_to_cpu(dep->inumber) == dp->i_ino);
                /*
                 * Skip .., but make sure the inode number is right.
                 */
                else if (dep->namelen == 2 &&
                         dep->name[0] == '.' && dep->name[1] == '.')
                        ASSERT(be64_to_cpu(dep->inumber) ==
                               dp->d_ops->sf_get_parent_ino(sfp));
                /*
                 * Normal entry, copy it into shortform.
                 */
                else {
                        sfep->namelen = dep->namelen;
                        xfs_dir2_sf_put_offset(sfep,
                                (xfs_dir2_data_aoff_t)
                                ((char *)dep - (char *)hdr));
                        memcpy(sfep->name, dep->name, dep->namelen);
                        dp->d_ops->sf_put_ino(sfp, sfep,
                                              be64_to_cpu(dep->inumber));
                        dp->d_ops->sf_put_ftype(sfep,
                                        dp->d_ops->data_get_ftype(dep));

                        sfep = dp->d_ops->sf_nextentry(sfp, sfep);
                }
                ptr += dp->d_ops->data_entsize(dep->namelen);
        }
        ASSERT((char *)sfep - (char *)sfp == size);

        /* now we are done with the block, we can shrink the inode */
        logflags = XFS_ILOG_CORE;
        error = xfs_dir2_shrink_inode(args, args->geo->datablk, bp);
        if (error) {
                ASSERT(error != -ENOSPC);
                goto out;
        }

        /*
         * The buffer is now unconditionally gone, whether
         * xfs_dir2_shrink_inode worked or not.
         *
         * Convert the inode to local format and copy the data in.
         */
        ASSERT(dp->i_df.if_bytes == 0);
        xfs_init_local_fork(dp, XFS_DATA_FORK, dst, size);
        dp->i_d.di_format = XFS_DINODE_FMT_LOCAL;
        dp->i_d.di_size = size;

        logflags |= XFS_ILOG_DDATA;
        xfs_dir2_sf_check(args);
out:
        xfs_trans_log_inode(args->trans, dp, logflags);
        kmem_free(dst);
        return error;
}

/*
 * Add a name to a shortform directory.
 * There are two algorithms, "easy" and "hard" which we decide on
 * before changing anything.
 * Convert to block form if necessary, if the new entry won't fit.
 */
int                                             /* error */
xfs_dir2_sf_addname(
        xfs_da_args_t           *args)          /* operation arguments */
{
        xfs_inode_t             *dp;            /* incore directory inode */
        int                     error;          /* error return value */
        int                     incr_isize;     /* total change in size */
        int                     new_isize;      /* di_size after adding name */
        int                     objchange;      /* changing to 8-byte inodes */
        xfs_dir2_data_aoff_t    offset = 0;     /* offset for new entry */
        int                     pick;           /* which algorithm to use */
        xfs_dir2_sf_hdr_t       *sfp;           /* shortform structure */
        xfs_dir2_sf_entry_t     *sfep = NULL;   /* shortform entry */

        trace_xfs_dir2_sf_addname(args);

        ASSERT(xfs_dir2_sf_lookup(args) == -ENOENT);
        dp = args->dp;
        ASSERT(dp->i_df.if_flags & XFS_IFINLINE);
        /*
         * Make sure the shortform value has some of its header.
         */
        if (dp->i_d.di_size < offsetof(xfs_dir2_sf_hdr_t, parent)) {
                ASSERT(XFS_FORCED_SHUTDOWN(dp->i_mount));
                return -EIO;
        }
        ASSERT(dp->i_df.if_bytes == dp->i_d.di_size);
        ASSERT(dp->i_df.if_u1.if_data != NULL);
        sfp = (xfs_dir2_sf_hdr_t *)dp->i_df.if_u1.if_data;
        ASSERT(dp->i_d.di_size >= xfs_dir2_sf_hdr_size(sfp->i8count));
        /*
         * Compute entry (and change in) size.
         */
        incr_isize = dp->d_ops->sf_entsize(sfp, args->namelen);
        objchange = 0;

        /*
         * Do we have to change to 8 byte inodes?
         */
        if (args->inumber > XFS_DIR2_MAX_SHORT_INUM && sfp->i8count == 0) {
                /*
                 * Yes, adjust the inode size.  old count + (parent + new)
                 */
                incr_isize += (sfp->count + 2) * XFS_INO64_DIFF;
                objchange = 1;
        }

        new_isize = (int)dp->i_d.di_size + incr_isize;
        /*
         * Won't fit as shortform any more (due to size),
         * or the pick routine says it won't (due to offset values).
         */
        if (new_isize > XFS_IFORK_DSIZE(dp) ||
            (pick =
             xfs_dir2_sf_addname_pick(args, objchange, &sfep, &offset)) == 0) {
                /*
                 * Just checking or no space reservation, it doesn't fit.
                 */
                if ((args->op_flags & XFS_DA_OP_JUSTCHECK) || args->total == 0)
                        return -ENOSPC;
                /*
                 * Convert to block form then add the name.
                 */
                error = xfs_dir2_sf_to_block(args);
                if (error)
                        return error;
                return xfs_dir2_block_addname(args);
        }
        /*
         * Just checking, it fits.
         */
        if (args->op_flags & XFS_DA_OP_JUSTCHECK)
                return 0;
        /*
         * Do it the easy way - just add it at the end.
         */
        if (pick == 1)
                xfs_dir2_sf_addname_easy(args, sfep, offset, new_isize);
        /*
         * Do it the hard way - look for a place to insert the new entry.
         * Convert to 8 byte inode numbers first if necessary.
         */
        else {
                ASSERT(pick == 2);
                if (objchange)
                        xfs_dir2_sf_toino8(args);
                xfs_dir2_sf_addname_hard(args, objchange, new_isize);
        }
        xfs_trans_log_inode(args->trans, dp, XFS_ILOG_CORE | XFS_ILOG_DDATA);
        return 0;
}

/*
 * Add the new entry the "easy" way.
 * This is copying the old directory and adding the new entry at the end.
 * Since it's sorted by "offset" we need room after the last offset
 * that's already there, and then room to convert to a block directory.
 * This is already checked by the pick routine.
 */
static void
xfs_dir2_sf_addname_easy(
        xfs_da_args_t           *args,          /* operation arguments */
        xfs_dir2_sf_entry_t     *sfep,          /* pointer to new entry */
        xfs_dir2_data_aoff_t    offset,         /* offset to use for new ent */
        int                     new_isize)      /* new directory size */
{
        int                     byteoff;        /* byte offset in sf dir */
        xfs_inode_t             *dp;            /* incore directory inode */
        xfs_dir2_sf_hdr_t       *sfp;           /* shortform structure */

        dp = args->dp;

        sfp = (xfs_dir2_sf_hdr_t *)dp->i_df.if_u1.if_data;
        byteoff = (int)((char *)sfep - (char *)sfp);
        /*
         * Grow the in-inode space.
         */
        xfs_idata_realloc(dp, dp->d_ops->sf_entsize(sfp, args->namelen),
                          XFS_DATA_FORK);
        /*
         * Need to set up again due to realloc of the inode data.
         */
        sfp = (xfs_dir2_sf_hdr_t *)dp->i_df.if_u1.if_data;
        sfep = (xfs_dir2_sf_entry_t *)((char *)sfp + byteoff);
        /*
         * Fill in the new entry.
         */
        sfep->namelen = args->namelen;
        xfs_dir2_sf_put_offset(sfep, offset);
        memcpy(sfep->name, args->name, sfep->namelen);
        dp->d_ops->sf_put_ino(sfp, sfep, args->inumber);
        dp->d_ops->sf_put_ftype(sfep, args->filetype);

        /*
         * Update the header and inode.
         */
        sfp->count++;
        if (args->inumber > XFS_DIR2_MAX_SHORT_INUM)
                sfp->i8count++;
        dp->i_d.di_size = new_isize;
        xfs_dir2_sf_check(args);
}

/*
 * Add the new entry the "hard" way.
 * The caller has already converted to 8 byte inode numbers if necessary,
 * in which case we need to leave the i8count at 1.
 * Find a hole that the new entry will fit into, and copy
 * the first part of the entries, the new entry, and the last part of
 * the entries.
 */
/* ARGSUSED */
static void
xfs_dir2_sf_addname_hard(
        xfs_da_args_t           *args,          /* operation arguments */
        int                     objchange,      /* changing inode number size */
        int                     new_isize)      /* new directory size */
{
        int                     add_datasize;   /* data size need for new ent */
        char                    *buf;           /* buffer for old */
        xfs_inode_t             *dp;            /* incore directory inode */
        int                     eof;            /* reached end of old dir */
        int                     nbytes;         /* temp for byte copies */
        xfs_dir2_data_aoff_t    new_offset;     /* next offset value */
        xfs_dir2_data_aoff_t    offset;         /* current offset value */
        int                     old_isize;      /* previous di_size */
        xfs_dir2_sf_entry_t     *oldsfep;       /* entry in original dir */
        xfs_dir2_sf_hdr_t       *oldsfp;        /* original shortform dir */
        xfs_dir2_sf_entry_t     *sfep;          /* entry in new dir */
        xfs_dir2_sf_hdr_t       *sfp;           /* new shortform dir */

        /*
         * Copy the old directory to the stack buffer.
         */
        dp = args->dp;

        sfp = (xfs_dir2_sf_hdr_t *)dp->i_df.if_u1.if_data;
        old_isize = (int)dp->i_d.di_size;
        buf = kmem_alloc(old_isize, 0);
        oldsfp = (xfs_dir2_sf_hdr_t *)buf;
        memcpy(oldsfp, sfp, old_isize);
        /*
         * Loop over the old directory finding the place we're going
         * to insert the new entry.
         * If it's going to end up at the end then oldsfep will point there.
         */
        for (offset = dp->d_ops->data_first_offset,
              oldsfep = xfs_dir2_sf_firstentry(oldsfp),
              add_datasize = dp->d_ops->data_entsize(args->namelen),
              eof = (char *)oldsfep == &buf[old_isize];
             !eof;
             offset = new_offset + dp->d_ops->data_entsize(oldsfep->namelen),
              oldsfep = dp->d_ops->sf_nextentry(oldsfp, oldsfep),
              eof = (char *)oldsfep == &buf[old_isize]) {
                new_offset = xfs_dir2_sf_get_offset(oldsfep);
                if (offset + add_datasize <= new_offset)
                        break;
        }
        /*
         * Get rid of the old directory, then allocate space for
         * the new one.  We do this so xfs_idata_realloc won't copy
         * the data.
         */
        xfs_idata_realloc(dp, -old_isize, XFS_DATA_FORK);
        xfs_idata_realloc(dp, new_isize, XFS_DATA_FORK);
        /*
         * Reset the pointer since the buffer was reallocated.
         */
        sfp = (xfs_dir2_sf_hdr_t *)dp->i_df.if_u1.if_data;
        /*
         * Copy the first part of the directory, including the header.
         */
        nbytes = (int)((char *)oldsfep - (char *)oldsfp);
        memcpy(sfp, oldsfp, nbytes);
        sfep = (xfs_dir2_sf_entry_t *)((char *)sfp + nbytes);
        /*
         * Fill in the new entry, and update the header counts.
         */
        sfep->namelen = args->namelen;
        xfs_dir2_sf_put_offset(sfep, offset);
        memcpy(sfep->name, args->name, sfep->namelen);
        dp->d_ops->sf_put_ino(sfp, sfep, args->inumber);
        dp->d_ops->sf_put_ftype(sfep, args->filetype);
        sfp->count++;
        if (args->inumber > XFS_DIR2_MAX_SHORT_INUM && !objchange)
                sfp->i8count++;
        /*
         * If there's more left to copy, do that.
         */
        if (!eof) {
                sfep = dp->d_ops->sf_nextentry(sfp, sfep);
                memcpy(sfep, oldsfep, old_isize - nbytes);
        }
        kmem_free(buf);
        dp->i_d.di_size = new_isize;
        xfs_dir2_sf_check(args);
}

/*
 * Decide if the new entry will fit at all.
 * If it will fit, pick between adding the new entry to the end (easy)
 * or somewhere else (hard).
 * Return 0 (won't fit), 1 (easy), 2 (hard).
 */
/*ARGSUSED*/
static int                                      /* pick result */
xfs_dir2_sf_addname_pick(
        xfs_da_args_t           *args,          /* operation arguments */
        int                     objchange,      /* inode # size changes */
        xfs_dir2_sf_entry_t     **sfepp,        /* out(1): new entry ptr */
        xfs_dir2_data_aoff_t    *offsetp)       /* out(1): new offset */
{
        xfs_inode_t             *dp;            /* incore directory inode */
        int                     holefit;        /* found hole it will fit in */
        int                     i;              /* entry number */
        xfs_dir2_data_aoff_t    offset;         /* data block offset */
        xfs_dir2_sf_entry_t     *sfep;          /* shortform entry */
        xfs_dir2_sf_hdr_t       *sfp;           /* shortform structure */
        int                     size;           /* entry's data size */
        int                     used;           /* data bytes used */

        dp = args->dp;

        sfp = (xfs_dir2_sf_hdr_t *)dp->i_df.if_u1.if_data;
        size = dp->d_ops->data_entsize(args->namelen);
        offset = dp->d_ops->data_first_offset;
        sfep = xfs_dir2_sf_firstentry(sfp);
        holefit = 0;
        /*
         * Loop over sf entries.
         * Keep track of data offset and whether we've seen a place
         * to insert the new entry.
         */
        for (i = 0; i < sfp->count; i++) {
                if (!holefit)
                        holefit = offset + size <= xfs_dir2_sf_get_offset(sfep);
                offset = xfs_dir2_sf_get_offset(sfep) +
                         dp->d_ops->data_entsize(sfep->namelen);
                sfep = dp->d_ops->sf_nextentry(sfp, sfep);
        }
        /*
         * Calculate data bytes used excluding the new entry, if this
         * was a data block (block form directory).
         */
        used = offset +
               (sfp->count + 3) * (uint)sizeof(xfs_dir2_leaf_entry_t) +
               (uint)sizeof(xfs_dir2_block_tail_t);
        /*
         * If it won't fit in a block form then we can't insert it,
         * we'll go back, convert to block, then try the insert and convert
         * to leaf.
         */
        if (used + (holefit ? 0 : size) > args->geo->blksize)
                return 0;
        /*
         * If changing the inode number size, do it the hard way.
         */
        if (objchange)
                return 2;
        /*
         * If it won't fit at the end then do it the hard way (use the hole).
         */
        if (used + size > args->geo->blksize)
                return 2;
        /*
         * Do it the easy way.
         */
        *sfepp = sfep;
        *offsetp = offset;
        return 1;
}

#ifdef DEBUG
/*
 * Check consistency of shortform directory, assert if bad.
 */
static void
xfs_dir2_sf_check(
        xfs_da_args_t           *args)          /* operation arguments */
{
        xfs_inode_t             *dp;            /* incore directory inode */
        int                     i;              /* entry number */
        int                     i8count;        /* number of big inode#s */
        xfs_ino_t               ino;            /* entry inode number */
        int                     offset;         /* data offset */
        xfs_dir2_sf_entry_t     *sfep;          /* shortform dir entry */
        xfs_dir2_sf_hdr_t       *sfp;           /* shortform structure */

        dp = args->dp;

        sfp = (xfs_dir2_sf_hdr_t *)dp->i_df.if_u1.if_data;
        offset = dp->d_ops->data_first_offset;
        ino = dp->d_ops->sf_get_parent_ino(sfp);
        i8count = ino > XFS_DIR2_MAX_SHORT_INUM;

        for (i = 0, sfep = xfs_dir2_sf_firstentry(sfp);
             i < sfp->count;
             i++, sfep = dp->d_ops->sf_nextentry(sfp, sfep)) {
                ASSERT(xfs_dir2_sf_get_offset(sfep) >= offset);
                ino = dp->d_ops->sf_get_ino(sfp, sfep);
                i8count += ino > XFS_DIR2_MAX_SHORT_INUM;
                offset =
                        xfs_dir2_sf_get_offset(sfep) +
                        dp->d_ops->data_entsize(sfep->namelen);
                ASSERT(dp->d_ops->sf_get_ftype(sfep) < XFS_DIR3_FT_MAX);
        }
        ASSERT(i8count == sfp->i8count);
        ASSERT((char *)sfep - (char *)sfp == dp->i_d.di_size);
        ASSERT(offset +
               (sfp->count + 2) * (uint)sizeof(xfs_dir2_leaf_entry_t) +
               (uint)sizeof(xfs_dir2_block_tail_t) <= args->geo->blksize);
}
#endif  /* DEBUG */

/* Verify the consistency of an inline directory. */
xfs_failaddr_t
xfs_dir2_sf_verify(
        struct xfs_inode                *ip)
{
        struct xfs_mount                *mp = ip->i_mount;
        struct xfs_dir2_sf_hdr          *sfp;
        struct xfs_dir2_sf_entry        *sfep;
        struct xfs_dir2_sf_entry        *next_sfep;
        char                            *endp;
        const struct xfs_dir_ops        *dops;
        struct xfs_ifork                *ifp;
        xfs_ino_t                       ino;
        int                             i;
        int                             i8count;
        int                             offset;
        int                             size;
        int                             error;
        uint8_t                         filetype;

        ASSERT(ip->i_d.di_format == XFS_DINODE_FMT_LOCAL);
        /*
         * xfs_iread calls us before xfs_setup_inode sets up ip->d_ops,
         * so we can only trust the mountpoint to have the right pointer.
         */
        dops = xfs_dir_get_ops(mp, NULL);

        ifp = XFS_IFORK_PTR(ip, XFS_DATA_FORK);
        sfp = (struct xfs_dir2_sf_hdr *)ifp->if_u1.if_data;
        size = ifp->if_bytes;

        /*
         * Give up if the directory is way too short.
         */
        if (size <= offsetof(struct xfs_dir2_sf_hdr, parent) ||
            size < xfs_dir2_sf_hdr_size(sfp->i8count))
                return __this_address;

        endp = (char *)sfp + size;

        /* Check .. entry */
        ino = dops->sf_get_parent_ino(sfp);
        i8count = ino > XFS_DIR2_MAX_SHORT_INUM;
        error = xfs_dir_ino_validate(mp, ino);
        if (error)
                return __this_address;
        offset = dops->data_first_offset;

        /* Check all reported entries */
        sfep = xfs_dir2_sf_firstentry(sfp);
        for (i = 0; i < sfp->count; i++) {
                /*
                 * struct xfs_dir2_sf_entry has a variable length.
                 * Check the fixed-offset parts of the structure are
                 * within the data buffer.
                 */
                if (((char *)sfep + sizeof(*sfep)) >= endp)
                        return __this_address;

                /* Don't allow names with known bad length. */
                if (sfep->namelen == 0)
                        return __this_address;

                /*
                 * Check that the variable-length part of the structure is
                 * within the data buffer.  The next entry starts after the
                 * name component, so nextentry is an acceptable test.
                 */
                next_sfep = dops->sf_nextentry(sfp, sfep);
                if (endp < (char *)next_sfep)
                        return __this_address;

                /* Check that the offsets always increase. */
                if (xfs_dir2_sf_get_offset(sfep) < offset)
                        return __this_address;

                /* Check the inode number. */
                ino = dops->sf_get_ino(sfp, sfep);
                i8count += ino > XFS_DIR2_MAX_SHORT_INUM;
                error = xfs_dir_ino_validate(mp, ino);
                if (error)
                        return __this_address;

                /* Check the file type. */
                filetype = dops->sf_get_ftype(sfep);
                if (filetype >= XFS_DIR3_FT_MAX)
                        return __this_address;

                offset = xfs_dir2_sf_get_offset(sfep) +
                                dops->data_entsize(sfep->namelen);

                sfep = next_sfep;
        }
        if (i8count != sfp->i8count)
                return __this_address;
        if ((void *)sfep != (void *)endp)
                return __this_address;

        /* Make sure this whole thing ought to be in local format. */
        if (offset + (sfp->count + 2) * (uint)sizeof(xfs_dir2_leaf_entry_t) +
            (uint)sizeof(xfs_dir2_block_tail_t) > mp->m_dir_geo->blksize)
                return __this_address;

        return NULL;
}

/*
 * Create a new (shortform) directory.
 */
int                                     /* error, always 0 */
xfs_dir2_sf_create(
        xfs_da_args_t   *args,          /* operation arguments */
        xfs_ino_t       pino)           /* parent inode number */
{
        xfs_inode_t     *dp;            /* incore directory inode */
        int             i8count;        /* parent inode is an 8-byte number */
        xfs_dir2_sf_hdr_t *sfp;         /* shortform structure */
        int             size;           /* directory size */

        trace_xfs_dir2_sf_create(args);

        dp = args->dp;

        ASSERT(dp != NULL);
        ASSERT(dp->i_d.di_size == 0);
        /*
         * If it's currently a zero-length extent file,
         * convert it to local format.
         */
        if (dp->i_d.di_format == XFS_DINODE_FMT_EXTENTS) {
                dp->i_df.if_flags &= ~XFS_IFEXTENTS;    /* just in case */
                dp->i_d.di_format = XFS_DINODE_FMT_LOCAL;
                xfs_trans_log_inode(args->trans, dp, XFS_ILOG_CORE);
                dp->i_df.if_flags |= XFS_IFINLINE;
        }
        ASSERT(dp->i_df.if_flags & XFS_IFINLINE);
        ASSERT(dp->i_df.if_bytes == 0);
        i8count = pino > XFS_DIR2_MAX_SHORT_INUM;
        size = xfs_dir2_sf_hdr_size(i8count);
        /*
         * Make a buffer for the data.
         */
        xfs_idata_realloc(dp, size, XFS_DATA_FORK);
        /*
         * Fill in the header,
         */
        sfp = (xfs_dir2_sf_hdr_t *)dp->i_df.if_u1.if_data;
        sfp->i8count = i8count;
        /*
         * Now can put in the inode number, since i8count is set.
         */
        dp->d_ops->sf_put_parent_ino(sfp, pino);
        sfp->count = 0;
        dp->i_d.di_size = size;
        xfs_dir2_sf_check(args);
        xfs_trans_log_inode(args->trans, dp, XFS_ILOG_CORE | XFS_ILOG_DDATA);
        return 0;
}

/*
 * Lookup an entry in a shortform directory.
 * Returns EEXIST if found, ENOENT if not found.
 */
int                                             /* error */
xfs_dir2_sf_lookup(
        xfs_da_args_t           *args)          /* operation arguments */
{
        xfs_inode_t             *dp;            /* incore directory inode */
        int                     i;              /* entry index */
        int                     error;
        xfs_dir2_sf_entry_t     *sfep;          /* shortform directory entry */
        xfs_dir2_sf_hdr_t       *sfp;           /* shortform structure */
        enum xfs_dacmp          cmp;            /* comparison result */
        xfs_dir2_sf_entry_t     *ci_sfep;       /* case-insens. entry */

        trace_xfs_dir2_sf_lookup(args);

        xfs_dir2_sf_check(args);
        dp = args->dp;

        ASSERT(dp->i_df.if_flags & XFS_IFINLINE);
        /*
         * Bail out if the directory is way too short.
         */
        if (dp->i_d.di_size < offsetof(xfs_dir2_sf_hdr_t, parent)) {
                ASSERT(XFS_FORCED_SHUTDOWN(dp->i_mount));
                return -EIO;
        }
        ASSERT(dp->i_df.if_bytes == dp->i_d.di_size);
        ASSERT(dp->i_df.if_u1.if_data != NULL);
        sfp = (xfs_dir2_sf_hdr_t *)dp->i_df.if_u1.if_data;
        ASSERT(dp->i_d.di_size >= xfs_dir2_sf_hdr_size(sfp->i8count));
        /*
         * Special case for .
         */
        if (args->namelen == 1 && args->name[0] == '.') {
                args->inumber = dp->i_ino;
                args->cmpresult = XFS_CMP_EXACT;
                args->filetype = XFS_DIR3_FT_DIR;
                return -EEXIST;
        }
        /*
         * Special case for ..
         */
        if (args->namelen == 2 &&
            args->name[0] == '.' && args->name[1] == '.') {
                args->inumber = dp->d_ops->sf_get_parent_ino(sfp);
                args->cmpresult = XFS_CMP_EXACT;
                args->filetype = XFS_DIR3_FT_DIR;
                return -EEXIST;
        }
        /*
         * Loop over all the entries trying to match ours.
         */
        ci_sfep = NULL;
        for (i = 0, sfep = xfs_dir2_sf_firstentry(sfp); i < sfp->count;
             i++, sfep = dp->d_ops->sf_nextentry(sfp, sfep)) {
                /*
                 * Compare name and if it's an exact match, return the inode
                 * number. If it's the first case-insensitive match, store the
                 * inode number and continue looking for an exact match.
                 */
                cmp = dp->i_mount->m_dirnameops->compname(args, sfep->name,
                                                                sfep->namelen);
                if (cmp != XFS_CMP_DIFFERENT && cmp != args->cmpresult) {
                        args->cmpresult = cmp;
                        args->inumber = dp->d_ops->sf_get_ino(sfp, sfep);
                        args->filetype = dp->d_ops->sf_get_ftype(sfep);
                        if (cmp == XFS_CMP_EXACT)
                                return -EEXIST;
                        ci_sfep = sfep;
                }
        }
        ASSERT(args->op_flags & XFS_DA_OP_OKNOENT);
        /*
         * Here, we can only be doing a lookup (not a rename or replace).
         * If a case-insensitive match was not found, return -ENOENT.
         */
        if (!ci_sfep)
                return -ENOENT;
        /* otherwise process the CI match as required by the caller */
        error = xfs_dir_cilookup_result(args, ci_sfep->name, ci_sfep->namelen);
        return error;
}

/*
 * Remove an entry from a shortform directory.
 */
int                                             /* error */
xfs_dir2_sf_removename(
        xfs_da_args_t           *args)
{
        int                     byteoff;        /* offset of removed entry */
        xfs_inode_t             *dp;            /* incore directory inode */
        int                     entsize;        /* this entry's size */
        int                     i;              /* shortform entry index */
        int                     newsize;        /* new inode size */
        int                     oldsize;        /* old inode size */
        xfs_dir2_sf_entry_t     *sfep;          /* shortform directory entry */
        xfs_dir2_sf_hdr_t       *sfp;           /* shortform structure */

        trace_xfs_dir2_sf_removename(args);

        dp = args->dp;

        ASSERT(dp->i_df.if_flags & XFS_IFINLINE);
        oldsize = (int)dp->i_d.di_size;
        /*
         * Bail out if the directory is way too short.
         */
        if (oldsize < offsetof(xfs_dir2_sf_hdr_t, parent)) {
                ASSERT(XFS_FORCED_SHUTDOWN(dp->i_mount));
                return -EIO;
        }
        ASSERT(dp->i_df.if_bytes == oldsize);
        ASSERT(dp->i_df.if_u1.if_data != NULL);
        sfp = (xfs_dir2_sf_hdr_t *)dp->i_df.if_u1.if_data;
        ASSERT(oldsize >= xfs_dir2_sf_hdr_size(sfp->i8count));
        /*
         * Loop over the old directory entries.
         * Find the one we're deleting.
         */
        for (i = 0, sfep = xfs_dir2_sf_firstentry(sfp); i < sfp->count;
             i++, sfep = dp->d_ops->sf_nextentry(sfp, sfep)) {
                if (xfs_da_compname(args, sfep->name, sfep->namelen) ==
                                                                XFS_CMP_EXACT) {
                        ASSERT(dp->d_ops->sf_get_ino(sfp, sfep) ==
                               args->inumber);
                        break;
                }
        }
        /*
         * Didn't find it.
         */
        if (i == sfp->count)
                return -ENOENT;
        /*
         * Calculate sizes.
         */
        byteoff = (int)((char *)sfep - (char *)sfp);
        entsize = dp->d_ops->sf_entsize(sfp, args->namelen);
        newsize = oldsize - entsize;
        /*
         * Copy the part if any after the removed entry, sliding it down.
         */
        if (byteoff + entsize < oldsize)
                memmove((char *)sfp + byteoff, (char *)sfp + byteoff + entsize,
                        oldsize - (byteoff + entsize));
        /*
         * Fix up the header and file size.
         */
        sfp->count--;
        dp->i_d.di_size = newsize;
        /*
         * Reallocate, making it smaller.
         */
        xfs_idata_realloc(dp, newsize - oldsize, XFS_DATA_FORK);
        sfp = (xfs_dir2_sf_hdr_t *)dp->i_df.if_u1.if_data;
        /*
         * Are we changing inode number size?
         */
        if (args->inumber > XFS_DIR2_MAX_SHORT_INUM) {
                if (sfp->i8count == 1)
                        xfs_dir2_sf_toino4(args);
                else
                        sfp->i8count--;
        }
        xfs_dir2_sf_check(args);
        xfs_trans_log_inode(args->trans, dp, XFS_ILOG_CORE | XFS_ILOG_DDATA);
        return 0;
}

/*
 * Replace the inode number of an entry in a shortform directory.
 */
int                                             /* error */
xfs_dir2_sf_replace(
        xfs_da_args_t           *args)          /* operation arguments */
{
        xfs_inode_t             *dp;            /* incore directory inode */
        int                     i;              /* entry index */
        xfs_ino_t               ino=0;          /* entry old inode number */
        int                     i8elevated;     /* sf_toino8 set i8count=1 */
        xfs_dir2_sf_entry_t     *sfep;          /* shortform directory entry */
        xfs_dir2_sf_hdr_t       *sfp;           /* shortform structure */

        trace_xfs_dir2_sf_replace(args);

        dp = args->dp;

        ASSERT(dp->i_df.if_flags & XFS_IFINLINE);
        /*
         * Bail out if the shortform directory is way too small.
         */
        if (dp->i_d.di_size < offsetof(xfs_dir2_sf_hdr_t, parent)) {
                ASSERT(XFS_FORCED_SHUTDOWN(dp->i_mount));
                return -EIO;
        }
        ASSERT(dp->i_df.if_bytes == dp->i_d.di_size);
        ASSERT(dp->i_df.if_u1.if_data != NULL);
        sfp = (xfs_dir2_sf_hdr_t *)dp->i_df.if_u1.if_data;
        ASSERT(dp->i_d.di_size >= xfs_dir2_sf_hdr_size(sfp->i8count));

        /*
         * New inode number is large, and need to convert to 8-byte inodes.
         */
        if (args->inumber > XFS_DIR2_MAX_SHORT_INUM && sfp->i8count == 0) {
                int     error;                  /* error return value */
                int     newsize;                /* new inode size */

                newsize = dp->i_df.if_bytes + (sfp->count + 1) * XFS_INO64_DIFF;
                /*
                 * Won't fit as shortform, convert to block then do replace.
                 */
                if (newsize > XFS_IFORK_DSIZE(dp)) {
                        error = xfs_dir2_sf_to_block(args);
                        if (error) {
                                return error;
                        }
                        return xfs_dir2_block_replace(args);
                }
                /*
                 * Still fits, convert to 8-byte now.
                 */
                xfs_dir2_sf_toino8(args);
                i8elevated = 1;

                sfp = (xfs_dir2_sf_hdr_t *)dp->i_df.if_u1.if_data;
        } else
                i8elevated = 0;

        ASSERT(args->namelen != 1 || args->name[0] != '.');
        /*
         * Replace ..'s entry.
         */
        if (args->namelen == 2 &&
            args->name[0] == '.' && args->name[1] == '.') {
                ino = dp->d_ops->sf_get_parent_ino(sfp);
                ASSERT(args->inumber != ino);
                dp->d_ops->sf_put_parent_ino(sfp, args->inumber);
        }
        /*
         * Normal entry, look for the name.
         */
        else {
                for (i = 0, sfep = xfs_dir2_sf_firstentry(sfp); i < sfp->count;
                     i++, sfep = dp->d_ops->sf_nextentry(sfp, sfep)) {
                        if (xfs_da_compname(args, sfep->name, sfep->namelen) ==
                                                                XFS_CMP_EXACT) {
                                ino = dp->d_ops->sf_get_ino(sfp, sfep);
                                ASSERT(args->inumber != ino);
                                dp->d_ops->sf_put_ino(sfp, sfep, args->inumber);
                                dp->d_ops->sf_put_ftype(sfep, args->filetype);
                                break;
                        }
                }
                /*
                 * Didn't find it.
                 */
                if (i == sfp->count) {
                        ASSERT(args->op_flags & XFS_DA_OP_OKNOENT);
                        if (i8elevated)
                                xfs_dir2_sf_toino4(args);
                        return -ENOENT;
                }
        }
        /*
         * See if the old number was large, the new number is small.
         */
        if (ino > XFS_DIR2_MAX_SHORT_INUM &&
            args->inumber <= XFS_DIR2_MAX_SHORT_INUM) {
                /*
                 * And the old count was one, so need to convert to small.
                 */
                if (sfp->i8count == 1)
                        xfs_dir2_sf_toino4(args);
                else
                        sfp->i8count--;
        }
        /*
         * See if the old number was small, the new number is large.
         */
        if (ino <= XFS_DIR2_MAX_SHORT_INUM &&
            args->inumber > XFS_DIR2_MAX_SHORT_INUM) {
                /*
                 * add to the i8count unless we just converted to 8-byte
                 * inodes (which does an implied i8count = 1)
                 */
                ASSERT(sfp->i8count != 0);
                if (!i8elevated)
                        sfp->i8count++;
        }
        xfs_dir2_sf_check(args);
        xfs_trans_log_inode(args->trans, dp, XFS_ILOG_DDATA);
        return 0;
}

/*
 * Convert from 8-byte inode numbers to 4-byte inode numbers.
 * The last 8-byte inode number is gone, but the count is still 1.
 */
static void
xfs_dir2_sf_toino4(
        xfs_da_args_t           *args)          /* operation arguments */
{
        char                    *buf;           /* old dir's buffer */
        xfs_inode_t             *dp;            /* incore directory inode */
        int                     i;              /* entry index */
        int                     newsize;        /* new inode size */
        xfs_dir2_sf_entry_t     *oldsfep;       /* old sf entry */
        xfs_dir2_sf_hdr_t       *oldsfp;        /* old sf directory */
        int                     oldsize;        /* old inode size */
        xfs_dir2_sf_entry_t     *sfep;          /* new sf entry */
        xfs_dir2_sf_hdr_t       *sfp;           /* new sf directory */

        trace_xfs_dir2_sf_toino4(args);

        dp = args->dp;

        /*
         * Copy the old directory to the buffer.
         * Then nuke it from the inode, and add the new buffer to the inode.
         * Don't want xfs_idata_realloc copying the data here.
         */
        oldsize = dp->i_df.if_bytes;
        buf = kmem_alloc(oldsize, 0);
        oldsfp = (xfs_dir2_sf_hdr_t *)dp->i_df.if_u1.if_data;
        ASSERT(oldsfp->i8count == 1);
        memcpy(buf, oldsfp, oldsize);
        /*
         * Compute the new inode size.
         */
        newsize = oldsize - (oldsfp->count + 1) * XFS_INO64_DIFF;
        xfs_idata_realloc(dp, -oldsize, XFS_DATA_FORK);
        xfs_idata_realloc(dp, newsize, XFS_DATA_FORK);
        /*
         * Reset our pointers, the data has moved.
         */
        oldsfp = (xfs_dir2_sf_hdr_t *)buf;
        sfp = (xfs_dir2_sf_hdr_t *)dp->i_df.if_u1.if_data;
        /*
         * Fill in the new header.
         */
        sfp->count = oldsfp->count;
        sfp->i8count = 0;
        dp->d_ops->sf_put_parent_ino(sfp, dp->d_ops->sf_get_parent_ino(oldsfp));
        /*
         * Copy the entries field by field.
         */
        for (i = 0, sfep = xfs_dir2_sf_firstentry(sfp),
                    oldsfep = xfs_dir2_sf_firstentry(oldsfp);
             i < sfp->count;
             i++, sfep = dp->d_ops->sf_nextentry(sfp, sfep),
                  oldsfep = dp->d_ops->sf_nextentry(oldsfp, oldsfep)) {
                sfep->namelen = oldsfep->namelen;
                memcpy(sfep->offset, oldsfep->offset, sizeof(sfep->offset));
                memcpy(sfep->name, oldsfep->name, sfep->namelen);
                dp->d_ops->sf_put_ino(sfp, sfep,
                                      dp->d_ops->sf_get_ino(oldsfp, oldsfep));
                dp->d_ops->sf_put_ftype(sfep, dp->d_ops->sf_get_ftype(oldsfep));
        }
        /*
         * Clean up the inode.
         */
        kmem_free(buf);
        dp->i_d.di_size = newsize;
        xfs_trans_log_inode(args->trans, dp, XFS_ILOG_CORE | XFS_ILOG_DDATA);
}

/*
 * Convert existing entries from 4-byte inode numbers to 8-byte inode numbers.
 * The new entry w/ an 8-byte inode number is not there yet; we leave with
 * i8count set to 1, but no corresponding 8-byte entry.
 */
static void
xfs_dir2_sf_toino8(
        xfs_da_args_t           *args)          /* operation arguments */
{
        char                    *buf;           /* old dir's buffer */
        xfs_inode_t             *dp;            /* incore directory inode */
        int                     i;              /* entry index */
        int                     newsize;        /* new inode size */
        xfs_dir2_sf_entry_t     *oldsfep;       /* old sf entry */
        xfs_dir2_sf_hdr_t       *oldsfp;        /* old sf directory */
        int                     oldsize;        /* old inode size */
        xfs_dir2_sf_entry_t     *sfep;          /* new sf entry */
        xfs_dir2_sf_hdr_t       *sfp;           /* new sf directory */

        trace_xfs_dir2_sf_toino8(args);

        dp = args->dp;

        /*
         * Copy the old directory to the buffer.
         * Then nuke it from the inode, and add the new buffer to the inode.
         * Don't want xfs_idata_realloc copying the data here.
         */
        oldsize = dp->i_df.if_bytes;
        buf = kmem_alloc(oldsize, 0);
        oldsfp = (xfs_dir2_sf_hdr_t *)dp->i_df.if_u1.if_data;
        ASSERT(oldsfp->i8count == 0);
        memcpy(buf, oldsfp, oldsize);
        /*
         * Compute the new inode size (nb: entry count + 1 for parent)
         */
        newsize = oldsize + (oldsfp->count + 1) * XFS_INO64_DIFF;
        xfs_idata_realloc(dp, -oldsize, XFS_DATA_FORK);
        xfs_idata_realloc(dp, newsize, XFS_DATA_FORK);
        /*
         * Reset our pointers, the data has moved.
         */
        oldsfp = (xfs_dir2_sf_hdr_t *)buf;
        sfp = (xfs_dir2_sf_hdr_t *)dp->i_df.if_u1.if_data;
        /*
         * Fill in the new header.
         */
        sfp->count = oldsfp->count;
        sfp->i8count = 1;
        dp->d_ops->sf_put_parent_ino(sfp, dp->d_ops->sf_get_parent_ino(oldsfp));
        /*
         * Copy the entries field by field.
         */
        for (i = 0, sfep = xfs_dir2_sf_firstentry(sfp),
                    oldsfep = xfs_dir2_sf_firstentry(oldsfp);
             i < sfp->count;
             i++, sfep = dp->d_ops->sf_nextentry(sfp, sfep),
                  oldsfep = dp->d_ops->sf_nextentry(oldsfp, oldsfep)) {
                sfep->namelen = oldsfep->namelen;
                memcpy(sfep->offset, oldsfep->offset, sizeof(sfep->offset));
                memcpy(sfep->name, oldsfep->name, sfep->namelen);
                dp->d_ops->sf_put_ino(sfp, sfep,
                                      dp->d_ops->sf_get_ino(oldsfp, oldsfep));
                dp->d_ops->sf_put_ftype(sfep, dp->d_ops->sf_get_ftype(oldsfep));
        }
        /*
         * Clean up the inode.
         */
        kmem_free(buf);
        dp->i_d.di_size = newsize;
        xfs_trans_log_inode(args->trans, dp, XFS_ILOG_CORE | XFS_ILOG_DDATA);
}