fs/freevxfs/vxfs_olt.c

0001 // SPDX-License-Identifier: GPL-2.0-only
0002 /*
0003  * Copyright (c) 2000-2001 Christoph Hellwig.
0004  */
0005
0006 /*
0007  * Veritas filesystem driver - object location table support.
0008  */
0009 #include <linux/fs.h>
0010 #include <linux/buffer_head.h>
0011 #include <linux/kernel.h>
0012
0013 #include "vxfs.h"
0014 #include "vxfs_olt.h"
0015 #include "vxfs_extern.h"
0016
0017
0018 static inline void
0019 vxfs_get_fshead(struct vxfs_oltfshead *fshp, struct vxfs_sb_info *infp)
0020 {
0021     BUG_ON(infp->vsi_fshino);
0022     infp->vsi_fshino = fs32_to_cpu(infp, fshp->olt_fsino[0]);
0023 }
0024
0025 static inline void
0026 vxfs_get_ilist(struct vxfs_oltilist *ilistp, struct vxfs_sb_info *infp)
0027 {
0028     BUG_ON(infp->vsi_iext);
0029     infp->vsi_iext = fs32_to_cpu(infp, ilistp->olt_iext[0]);
0030 }
0031
0032 static inline u_long
0033 vxfs_oblock(struct super_block *sbp, daddr_t block, u_long bsize)
0034 {
0035     BUG_ON(sbp->s_blocksize % bsize);
0036     return (block * (sbp->s_blocksize / bsize));
0037 }
0038
0039
0040 /**
0041  * vxfs_read_olt - read olt
0042  * @sbp:    superblock of the filesystem
0043  * @bsize:  blocksize of the filesystem
0044  *
0045  * Description:
0046  *   vxfs_read_olt reads the olt of the filesystem described by @sbp
0047  *   into main memory and does some basic setup.
0048  *
0049  * Returns:
0050  *   Zero on success, else a negative error code.
0051  */
0052 int
0053 vxfs_read_olt(struct super_block *sbp, u_long bsize)
0054 {
0055     struct vxfs_sb_info *infp = VXFS_SBI(sbp);
0056     struct buffer_head  *bp;
0057     struct vxfs_olt     *op;
0058     char            *oaddr, *eaddr;
0059
0060     bp = sb_bread(sbp, vxfs_oblock(sbp, infp->vsi_oltext, bsize));
0061     if (!bp || !bp->b_data)
0062         goto fail;
0063
0064     op = (struct vxfs_olt *)bp->b_data;
0065     if (fs32_to_cpu(infp, op->olt_magic) != VXFS_OLT_MAGIC) {
0066         printk(KERN_NOTICE "vxfs: ivalid olt magic number\n");
0067         goto fail;
0068     }
0069
0070     /*
0071      * It is in theory possible that vsi_oltsize is > 1.
0072      * I've not seen any such filesystem yet and I'm lazy..  --hch
0073      */
0074     if (infp->vsi_oltsize > 1) {
0075         printk(KERN_NOTICE "vxfs: oltsize > 1 detected.\n");
0076         printk(KERN_NOTICE "vxfs: please notify hch@infradead.org\n");
0077         goto fail;
0078     }
0079
0080     oaddr = bp->b_data + fs32_to_cpu(infp, op->olt_size);
0081     eaddr = bp->b_data + (infp->vsi_oltsize * sbp->s_blocksize);
0082
0083     while (oaddr < eaddr) {
0084         struct vxfs_oltcommon   *ocp =
0085             (struct vxfs_oltcommon *)oaddr;
0086
0087         switch (fs32_to_cpu(infp, ocp->olt_type)) {
0088         case VXFS_OLT_FSHEAD:
0089             vxfs_get_fshead((struct vxfs_oltfshead *)oaddr, infp);
0090             break;
0091         case VXFS_OLT_ILIST:
0092             vxfs_get_ilist((struct vxfs_oltilist *)oaddr, infp);
0093             break;
0094         }
0095
0096         oaddr += fs32_to_cpu(infp, ocp->olt_size);
0097     }
0098
0099     brelse(bp);
0100     return (infp->vsi_fshino && infp->vsi_iext) ? 0 : -EINVAL;
0101
0102 fail:
0103     brelse(bp);
0104     return -EINVAL;
0105 }