1 files changed, 305 insertions, 0 deletions

diff --git a/fs/efs/inode.c b/fs/efs/inode.c
new file mode 100644
index 000000000000..180607f9314d
--- /dev/null
+++ b/fs/efs/inode.c
@@ -0,0 +1,305 @@
+/*
+ * inode.c
+ *
+ * Copyright (c) 1999 Al Smith
+ *
+ * Portions derived from work (c) 1995,1996 Christian Vogelgsang,
+ *              and from work (c) 1998 Mike Shaver.
+ */
+
+#include <linux/efs_fs.h>
+#include <linux/efs_fs_sb.h>
+#include <linux/buffer_head.h>
+#include <linux/module.h>
+#include <linux/fs.h>
+
+static int efs_readpage(struct file *file, struct page *page)
+{
+        return block_read_full_page(page,efs_get_block);
+}
+static sector_t _efs_bmap(struct address_space *mapping, sector_t block)
+{
+        return generic_block_bmap(mapping,block,efs_get_block);
+}
+static struct address_space_operations efs_aops = {
+        .readpage = efs_readpage,
+        .sync_page = block_sync_page,
+        .bmap = _efs_bmap
+};
+
+static inline void extent_copy(efs_extent *src, efs_extent *dst) {
+        /*
+         * this is slightly evil. it doesn't just copy
+         * efs_extent from src to dst, it also mangles
+         * the bits so that dst ends up in cpu byte-order.
+         */
+
+        dst->cooked.ex_magic  =  (unsigned int) src->raw[0];
+        dst->cooked.ex_bn     = ((unsigned int) src->raw[1] << 16) |
+                                ((unsigned int) src->raw[2] <<  8) |
+                                ((unsigned int) src->raw[3] <<  0);
+        dst->cooked.ex_length =  (unsigned int) src->raw[4];
+        dst->cooked.ex_offset = ((unsigned int) src->raw[5] << 16) |
+                                ((unsigned int) src->raw[6] <<  8) |
+                                ((unsigned int) src->raw[7] <<  0);
+        return;
+}
+
+void efs_read_inode(struct inode *inode)
+{
+        int i, inode_index;
+        dev_t device;
+        u32 rdev;
+        struct buffer_head *bh;
+        struct efs_sb_info    *sb = SUPER_INFO(inode->i_sb);
+        struct efs_inode_info *in = INODE_INFO(inode);
+        efs_block_t block, offset;
+        struct efs_dinode *efs_inode;
+  
+        /*
+        ** EFS layout:
+        **
+        ** |   cylinder group    |   cylinder group    |   cylinder group ..etc
+        ** |inodes|data          |inodes|data          |inodes|data       ..etc
+        **
+        ** work out the inode block index, (considering initially that the
+        ** inodes are stored as consecutive blocks). then work out the block
+        ** number of that inode given the above layout, and finally the
+        ** offset of the inode within that block.
+        */
+
+        inode_index = inode->i_ino /
+                (EFS_BLOCKSIZE / sizeof(struct efs_dinode));
+
+        block = sb->fs_start + sb->first_block + 
+                (sb->group_size * (inode_index / sb->inode_blocks)) +
+                (inode_index % sb->inode_blocks);
+
+        offset = (inode->i_ino %
+                        (EFS_BLOCKSIZE / sizeof(struct efs_dinode))) *
+                sizeof(struct efs_dinode);
+
+        bh = sb_bread(inode->i_sb, block);
+        if (!bh) {
+                printk(KERN_WARNING "EFS: bread() failed at block %d\n", block);
+                goto read_inode_error;
+        }
+
+        efs_inode = (struct efs_dinode *) (bh->b_data + offset);
+    
+        inode->i_mode  = be16_to_cpu(efs_inode->di_mode);
+        inode->i_nlink = be16_to_cpu(efs_inode->di_nlink);
+        inode->i_uid   = (uid_t)be16_to_cpu(efs_inode->di_uid);
+        inode->i_gid   = (gid_t)be16_to_cpu(efs_inode->di_gid);
+        inode->i_size  = be32_to_cpu(efs_inode->di_size);
+        inode->i_atime.tv_sec = be32_to_cpu(efs_inode->di_atime);
+        inode->i_mtime.tv_sec = be32_to_cpu(efs_inode->di_mtime);
+        inode->i_ctime.tv_sec = be32_to_cpu(efs_inode->di_ctime);
+        inode->i_atime.tv_nsec = inode->i_mtime.tv_nsec = inode->i_ctime.tv_nsec = 0;
+
+        /* this is the number of blocks in the file */
+        if (inode->i_size == 0) {
+                inode->i_blocks = 0;
+        } else {
+                inode->i_blocks = ((inode->i_size - 1) >> EFS_BLOCKSIZE_BITS) + 1;
+        }
+
+        rdev = be16_to_cpu(efs_inode->di_u.di_dev.odev);
+        if (rdev == 0xffff) {
+                rdev = be32_to_cpu(efs_inode->di_u.di_dev.ndev);
+                if (sysv_major(rdev) > 0xfff)
+                        device = 0;
+                else
+                        device = MKDEV(sysv_major(rdev), sysv_minor(rdev));
+        } else
+                device = old_decode_dev(rdev);
+
+        /* get the number of extents for this object */
+        in->numextents = be16_to_cpu(efs_inode->di_numextents);
+        in->lastextent = 0;
+
+        /* copy the extents contained within the inode to memory */
+        for(i = 0; i < EFS_DIRECTEXTENTS; i++) {
+                extent_copy(&(efs_inode->di_u.di_extents[i]), &(in->extents[i]));
+                if (i < in->numextents && in->extents[i].cooked.ex_magic != 0) {
+                        printk(KERN_WARNING "EFS: extent %d has bad magic number in inode %lu\n", i, inode->i_ino);
+                        brelse(bh);
+                        goto read_inode_error;
+                }
+        }
+
+        brelse(bh);
+   
+#ifdef DEBUG
+        printk(KERN_DEBUG "EFS: read_inode(): inode %lu, extents %d, mode %o\n",
+                inode->i_ino, in->numextents, inode->i_mode);
+#endif
+
+        switch (inode->i_mode & S_IFMT) {
+                case S_IFDIR: 
+                        inode->i_op = &efs_dir_inode_operations; 
+                        inode->i_fop = &efs_dir_operations; 
+                        break;
+                case S_IFREG:
+                        inode->i_fop = &generic_ro_fops;
+                        inode->i_data.a_ops = &efs_aops;
+                        break;
+                case S_IFLNK:
+                        inode->i_op = &page_symlink_inode_operations;
+                        inode->i_data.a_ops = &efs_symlink_aops;
+                        break;
+                case S_IFCHR:
+                case S_IFBLK:
+                case S_IFIFO:
+                        init_special_inode(inode, inode->i_mode, device);
+                        break;
+                default:
+                        printk(KERN_WARNING "EFS: unsupported inode mode %o\n", inode->i_mode);
+                        goto read_inode_error;
+                        break;
+        }
+
+        return;
+        
+read_inode_error:
+        printk(KERN_WARNING "EFS: failed to read inode %lu\n", inode->i_ino);
+        make_bad_inode(inode);
+
+        return;
+}
+
+static inline efs_block_t
+efs_extent_check(efs_extent *ptr, efs_block_t block, struct efs_sb_info *sb) {
+        efs_block_t start;
+        efs_block_t length;
+        efs_block_t offset;
+
+        /*
+         * given an extent and a logical block within a file,
+         * can this block be found within this extent ?
+         */
+        start  = ptr->cooked.ex_bn;
+        length = ptr->cooked.ex_length;
+        offset = ptr->cooked.ex_offset;
+
+        if ((block >= offset) && (block < offset+length)) {
+                return(sb->fs_start + start + block - offset);
+        } else {
+                return 0;
+        }
+}
+
+efs_block_t efs_map_block(struct inode *inode, efs_block_t block) {
+        struct efs_sb_info    *sb = SUPER_INFO(inode->i_sb);
+        struct efs_inode_info *in = INODE_INFO(inode);
+        struct buffer_head    *bh = NULL;
+
+        int cur, last, first = 1;
+        int ibase, ioffset, dirext, direxts, indext, indexts;
+        efs_block_t iblock, result = 0, lastblock = 0;
+        efs_extent ext, *exts;
+
+        last = in->lastextent;
+
+        if (in->numextents <= EFS_DIRECTEXTENTS) {
+                /* first check the last extent we returned */
+                if ((result = efs_extent_check(&in->extents[last], block, sb)))
+                        return result;
+    
+                /* if we only have one extent then nothing can be found */
+                if (in->numextents == 1) {
+                        printk(KERN_ERR "EFS: map_block() failed to map (1 extent)\n");
+                        return 0;
+                }
+
+                direxts = in->numextents;
+
+                /*
+                 * check the stored extents in the inode
+                 * start with next extent and check forwards
+                 */
+                for(dirext = 1; dirext < direxts; dirext++) {
+                        cur = (last + dirext) % in->numextents;
+                        if ((result = efs_extent_check(&in->extents[cur], block, sb))) {
+                                in->lastextent = cur;
+                                return result;
+                        }
+                }
+
+                printk(KERN_ERR "EFS: map_block() failed to map block %u (dir)\n", block);
+                return 0;
+        }
+
+#ifdef DEBUG
+        printk(KERN_DEBUG "EFS: map_block(): indirect search for logical block %u\n", block);
+#endif
+        direxts = in->extents[0].cooked.ex_offset;
+        indexts = in->numextents;
+
+        for(indext = 0; indext < indexts; indext++) {
+                cur = (last + indext) % indexts;
+
+                /*
+                 * work out which direct extent contains `cur'.
+                 *
+                 * also compute ibase: i.e. the number of the first
+                 * indirect extent contained within direct extent `cur'.
+                 *
+                 */
+                ibase = 0;
+                for(dirext = 0; cur < ibase && dirext < direxts; dirext++) {
+                        ibase += in->extents[dirext].cooked.ex_length *
+                                (EFS_BLOCKSIZE / sizeof(efs_extent));
+                }
+
+                if (dirext == direxts) {
+                        /* should never happen */
+                        printk(KERN_ERR "EFS: couldn't find direct extent for indirect extent %d (block %u)\n", cur, block);
+                        if (bh) brelse(bh);
+                        return 0;
+                }
+                
+                /* work out block number and offset of this indirect extent */
+                iblock = sb->fs_start + in->extents[dirext].cooked.ex_bn +
+                        (cur - ibase) /
+                        (EFS_BLOCKSIZE / sizeof(efs_extent));
+                ioffset = (cur - ibase) %
+                        (EFS_BLOCKSIZE / sizeof(efs_extent));
+
+                if (first || lastblock != iblock) {
+                        if (bh) brelse(bh);
+
+                        bh = sb_bread(inode->i_sb, iblock);
+                        if (!bh) {
+                                printk(KERN_ERR "EFS: bread() failed at block %d\n", iblock);
+                                return 0;
+                        }
+#ifdef DEBUG
+                        printk(KERN_DEBUG "EFS: map_block(): read indirect extent block %d\n", iblock);
+#endif
+                        first = 0;
+                        lastblock = iblock;
+                }
+
+                exts = (efs_extent *) bh->b_data;
+
+                extent_copy(&(exts[ioffset]), &ext);
+
+                if (ext.cooked.ex_magic != 0) {
+                        printk(KERN_ERR "EFS: extent %d has bad magic number in block %d\n", cur, iblock);
+                        if (bh) brelse(bh);
+                        return 0;
+                }
+
+                if ((result = efs_extent_check(&ext, block, sb))) {
+                        if (bh) brelse(bh);
+                        in->lastextent = cur;
+                        return result;
+                }
+        }
+        if (bh) brelse(bh);
+        printk(KERN_ERR "EFS: map_block() failed to map block %u (indir)\n", block);
+        return 0;
+}  
+
+MODULE_LICENSE("GPL");