Linux-2.6.12-rc2v2.6.12-rc2

Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!

1 files changed, 475 insertions, 0 deletions

diff --git a/fs/sysv/itree.c b/fs/sysv/itree.c
new file mode 100644
index 000000000000..86f5f8d43d0f
--- /dev/null
+++ b/fs/sysv/itree.c
@@ -0,0 +1,475 @@
+/*
+ *  linux/fs/sysv/itree.c
+ *
+ *  Handling of indirect blocks' trees.
+ *  AV, Sep--Dec 2000
+ */
+
+#include <linux/buffer_head.h>
+#include <linux/mount.h>
+#include <linux/string.h>
+#include "sysv.h"
+
+enum {DIRECT = 10, DEPTH = 4};  /* Have triple indirect */
+
+static inline void dirty_indirect(struct buffer_head *bh, struct inode *inode)
+{
+        mark_buffer_dirty_inode(bh, inode);
+        if (IS_SYNC(inode))
+                sync_dirty_buffer(bh);
+}
+
+static int block_to_path(struct inode *inode, long block, int offsets[DEPTH])
+{
+        struct super_block *sb = inode->i_sb;
+        struct sysv_sb_info *sbi = SYSV_SB(sb);
+        int ptrs_bits = sbi->s_ind_per_block_bits;
+        unsigned long   indirect_blocks = sbi->s_ind_per_block,
+                        double_blocks = sbi->s_ind_per_block_2;
+        int n = 0;
+
+        if (block < 0) {
+                printk("sysv_block_map: block < 0\n");
+        } else if (block < DIRECT) {
+                offsets[n++] = block;
+        } else if ( (block -= DIRECT) < indirect_blocks) {
+                offsets[n++] = DIRECT;
+                offsets[n++] = block;
+        } else if ((block -= indirect_blocks) < double_blocks) {
+                offsets[n++] = DIRECT+1;
+                offsets[n++] = block >> ptrs_bits;
+                offsets[n++] = block & (indirect_blocks - 1);
+        } else if (((block -= double_blocks) >> (ptrs_bits * 2)) < indirect_blocks) {
+                offsets[n++] = DIRECT+2;
+                offsets[n++] = block >> (ptrs_bits * 2);
+                offsets[n++] = (block >> ptrs_bits) & (indirect_blocks - 1);
+                offsets[n++] = block & (indirect_blocks - 1);
+        } else {
+                /* nothing */;
+        }
+        return n;
+}
+
+static inline int block_to_cpu(struct sysv_sb_info *sbi, sysv_zone_t nr)
+{
+        return sbi->s_block_base + fs32_to_cpu(sbi, nr);
+}
+
+typedef struct {
+        sysv_zone_t     *p;
+        sysv_zone_t     key;
+        struct buffer_head *bh;
+} Indirect;
+
+static DEFINE_RWLOCK(pointers_lock);
+
+static inline void add_chain(Indirect *p, struct buffer_head *bh, sysv_zone_t *v)
+{
+        p->key = *(p->p = v);
+        p->bh = bh;
+}
+
+static inline int verify_chain(Indirect *from, Indirect *to)
+{
+        while (from <= to && from->key == *from->p)
+                from++;
+        return (from > to);
+}
+
+static inline sysv_zone_t *block_end(struct buffer_head *bh)
+{
+        return (sysv_zone_t*)((char*)bh->b_data + bh->b_size);
+}
+
+/*
+ * Requires read_lock(&pointers_lock) or write_lock(&pointers_lock)
+ */
+static Indirect *get_branch(struct inode *inode,
+                            int depth,
+                            int offsets[],
+                            Indirect chain[],
+                            int *err)
+{
+        struct super_block *sb = inode->i_sb;
+        Indirect *p = chain;
+        struct buffer_head *bh;
+
+        *err = 0;
+        add_chain(chain, NULL, SYSV_I(inode)->i_data + *offsets);
+        if (!p->key)
+                goto no_block;
+        while (--depth) {
+                int block = block_to_cpu(SYSV_SB(sb), p->key);
+                bh = sb_bread(sb, block);
+                if (!bh)
+                        goto failure;
+                if (!verify_chain(chain, p))
+                        goto changed;
+                add_chain(++p, bh, (sysv_zone_t*)bh->b_data + *++offsets);
+                if (!p->key)
+                        goto no_block;
+        }
+        return NULL;
+
+changed:
+        brelse(bh);
+        *err = -EAGAIN;
+        goto no_block;
+failure:
+        *err = -EIO;
+no_block:
+        return p;
+}
+
+static int alloc_branch(struct inode *inode,
+                        int num,
+                        int *offsets,
+                        Indirect *branch)
+{
+        int blocksize = inode->i_sb->s_blocksize;
+        int n = 0;
+        int i;
+
+        branch[0].key = sysv_new_block(inode->i_sb);
+        if (branch[0].key) for (n = 1; n < num; n++) {
+                struct buffer_head *bh;
+                int parent;
+                /* Allocate the next block */
+                branch[n].key = sysv_new_block(inode->i_sb);
+                if (!branch[n].key)
+                        break;
+                /*
+                 * Get buffer_head for parent block, zero it out and set 
+                 * the pointer to new one, then send parent to disk.
+                 */
+                parent = block_to_cpu(SYSV_SB(inode->i_sb), branch[n-1].key);
+                bh = sb_getblk(inode->i_sb, parent);
+                lock_buffer(bh);
+                memset(bh->b_data, 0, blocksize);
+                branch[n].bh = bh;
+                branch[n].p = (sysv_zone_t*) bh->b_data + offsets[n];
+                *branch[n].p = branch[n].key;
+                set_buffer_uptodate(bh);
+                unlock_buffer(bh);
+                dirty_indirect(bh, inode);
+        }
+        if (n == num)
+                return 0;
+
+        /* Allocation failed, free what we already allocated */
+        for (i = 1; i < n; i++)
+                bforget(branch[i].bh);
+        for (i = 0; i < n; i++)
+                sysv_free_block(inode->i_sb, branch[i].key);
+        return -ENOSPC;
+}
+
+static inline int splice_branch(struct inode *inode,
+                                Indirect chain[],
+                                Indirect *where,
+                                int num)
+{
+        int i;
+
+        /* Verify that place we are splicing to is still there and vacant */
+        write_lock(&pointers_lock);
+        if (!verify_chain(chain, where-1) || *where->p)
+                goto changed;
+        *where->p = where->key;
+        write_unlock(&pointers_lock);
+
+        inode->i_ctime = CURRENT_TIME_SEC;
+
+        /* had we spliced it onto indirect block? */
+        if (where->bh)
+                dirty_indirect(where->bh, inode);
+
+        if (IS_SYNC(inode))
+                sysv_sync_inode(inode);
+        else
+                mark_inode_dirty(inode);
+        return 0;
+
+changed:
+        write_unlock(&pointers_lock);
+        for (i = 1; i < num; i++)
+                bforget(where[i].bh);
+        for (i = 0; i < num; i++)
+                sysv_free_block(inode->i_sb, where[i].key);
+        return -EAGAIN;
+}
+
+static int get_block(struct inode *inode, sector_t iblock, struct buffer_head *bh_result, int create)
+{
+        int err = -EIO;
+        int offsets[DEPTH];
+        Indirect chain[DEPTH];
+        struct super_block *sb = inode->i_sb;
+        Indirect *partial;
+        int left;
+        int depth = block_to_path(inode, iblock, offsets);
+
+        if (depth == 0)
+                goto out;
+
+reread:
+        read_lock(&pointers_lock);
+        partial = get_branch(inode, depth, offsets, chain, &err);
+        read_unlock(&pointers_lock);
+
+        /* Simplest case - block found, no allocation needed */
+        if (!partial) {
+got_it:
+                map_bh(bh_result, sb, block_to_cpu(SYSV_SB(sb),
+                                        chain[depth-1].key));
+                /* Clean up and exit */
+                partial = chain+depth-1; /* the whole chain */
+                goto cleanup;
+        }
+
+        /* Next simple case - plain lookup or failed read of indirect block */
+        if (!create || err == -EIO) {
+cleanup:
+                while (partial > chain) {
+                        brelse(partial->bh);
+                        partial--;
+                }
+out:
+                return err;
+        }
+
+        /*
+         * Indirect block might be removed by truncate while we were
+         * reading it. Handling of that case (forget what we've got and
+         * reread) is taken out of the main path.
+         */
+        if (err == -EAGAIN)
+                goto changed;
+
+        left = (chain + depth) - partial;
+        err = alloc_branch(inode, left, offsets+(partial-chain), partial);
+        if (err)
+                goto cleanup;
+
+        if (splice_branch(inode, chain, partial, left) < 0)
+                goto changed;
+
+        set_buffer_new(bh_result);
+        goto got_it;
+
+changed:
+        while (partial > chain) {
+                brelse(partial->bh);
+                partial--;
+        }
+        goto reread;
+}
+
+static inline int all_zeroes(sysv_zone_t *p, sysv_zone_t *q)
+{
+        while (p < q)
+                if (*p++)
+                        return 0;
+        return 1;
+}
+
+static Indirect *find_shared(struct inode *inode,
+                                int depth,
+                                int offsets[],
+                                Indirect chain[],
+                                sysv_zone_t *top)
+{
+        Indirect *partial, *p;
+        int k, err;
+
+        *top = 0;
+        for (k = depth; k > 1 && !offsets[k-1]; k--)
+                ;
+
+        write_lock(&pointers_lock);
+        partial = get_branch(inode, k, offsets, chain, &err);
+        if (!partial)
+                partial = chain + k-1;
+        /*
+         * If the branch acquired continuation since we've looked at it -
+         * fine, it should all survive and (new) top doesn't belong to us.
+         */
+        if (!partial->key && *partial->p) {
+                write_unlock(&pointers_lock);
+                goto no_top;
+        }
+        for (p=partial; p>chain && all_zeroes((sysv_zone_t*)p->bh->b_data,p->p); p--)
+                ;
+        /*
+         * OK, we've found the last block that must survive. The rest of our
+         * branch should be detached before unlocking. However, if that rest
+         * of branch is all ours and does not grow immediately from the inode
+         * it's easier to cheat and just decrement partial->p.
+         */
+        if (p == chain + k - 1 && p > chain) {
+                p->p--;
+        } else {
+                *top = *p->p;
+                *p->p = 0;
+        }
+        write_unlock(&pointers_lock);
+
+        while (partial > p) {
+                brelse(partial->bh);
+                partial--;
+        }
+no_top:
+        return partial;
+}
+
+static inline void free_data(struct inode *inode, sysv_zone_t *p, sysv_zone_t *q)
+{
+        for ( ; p < q ; p++) {
+                sysv_zone_t nr = *p;
+                if (nr) {
+                        *p = 0;
+                        sysv_free_block(inode->i_sb, nr);
+                        mark_inode_dirty(inode);
+                }
+        }
+}
+
+static void free_branches(struct inode *inode, sysv_zone_t *p, sysv_zone_t *q, int depth)
+{
+        struct buffer_head * bh;
+        struct super_block *sb = inode->i_sb;
+
+        if (depth--) {
+                for ( ; p < q ; p++) {
+                        int block;
+                        sysv_zone_t nr = *p;
+                        if (!nr)
+                                continue;
+                        *p = 0;
+                        block = block_to_cpu(SYSV_SB(sb), nr);
+                        bh = sb_bread(sb, block);
+                        if (!bh)
+                                continue;
+                        free_branches(inode, (sysv_zone_t*)bh->b_data,
+                                        block_end(bh), depth);
+                        bforget(bh);
+                        sysv_free_block(sb, nr);
+                        mark_inode_dirty(inode);
+                }
+        } else
+                free_data(inode, p, q);
+}
+
+void sysv_truncate (struct inode * inode)
+{
+        sysv_zone_t *i_data = SYSV_I(inode)->i_data;
+        int offsets[DEPTH];
+        Indirect chain[DEPTH];
+        Indirect *partial;
+        sysv_zone_t nr = 0;
+        int n;
+        long iblock;
+        unsigned blocksize;
+
+        if (!(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode) ||
+            S_ISLNK(inode->i_mode)))
+                return;
+
+        blocksize = inode->i_sb->s_blocksize;
+        iblock = (inode->i_size + blocksize-1)
+                                        >> inode->i_sb->s_blocksize_bits;
+
+        block_truncate_page(inode->i_mapping, inode->i_size, get_block);
+
+        n = block_to_path(inode, iblock, offsets);
+        if (n == 0)
+                return;
+
+        if (n == 1) {
+                free_data(inode, i_data+offsets[0], i_data + DIRECT);
+                goto do_indirects;
+        }
+
+        partial = find_shared(inode, n, offsets, chain, &nr);
+        /* Kill the top of shared branch (already detached) */
+        if (nr) {
+                if (partial == chain)
+                        mark_inode_dirty(inode);
+                else
+                        dirty_indirect(partial->bh, inode);
+                free_branches(inode, &nr, &nr+1, (chain+n-1) - partial);
+        }
+        /* Clear the ends of indirect blocks on the shared branch */
+        while (partial > chain) {
+                free_branches(inode, partial->p + 1, block_end(partial->bh),
+                                (chain+n-1) - partial);
+                dirty_indirect(partial->bh, inode);
+                brelse (partial->bh);
+                partial--;
+        }
+do_indirects:
+        /* Kill the remaining (whole) subtrees (== subtrees deeper than...) */
+        while (n < DEPTH) {
+                nr = i_data[DIRECT + n - 1];
+                if (nr) {
+                        i_data[DIRECT + n - 1] = 0;
+                        mark_inode_dirty(inode);
+                        free_branches(inode, &nr, &nr+1, n);
+                }
+                n++;
+        }
+        inode->i_mtime = inode->i_ctime = CURRENT_TIME_SEC;
+        if (IS_SYNC(inode))
+                sysv_sync_inode (inode);
+        else
+                mark_inode_dirty(inode);
+}
+
+static unsigned sysv_nblocks(struct super_block *s, loff_t size)
+{
+        struct sysv_sb_info *sbi = SYSV_SB(s);
+        int ptrs_bits = sbi->s_ind_per_block_bits;
+        unsigned blocks, res, direct = DIRECT, i = DEPTH;
+        blocks = (size + s->s_blocksize - 1) >> s->s_blocksize_bits;
+        res = blocks;
+        while (--i && blocks > direct) {
+                blocks = ((blocks - direct - 1) >> ptrs_bits) + 1;
+                res += blocks;
+                direct = 1;
+        }
+        return blocks;
+}
+
+int sysv_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat)
+{
+        struct super_block *s = mnt->mnt_sb;
+        generic_fillattr(dentry->d_inode, stat);
+        stat->blocks = (s->s_blocksize / 512) * sysv_nblocks(s, stat->size);
+        stat->blksize = s->s_blocksize;
+        return 0;
+}
+
+static int sysv_writepage(struct page *page, struct writeback_control *wbc)
+{
+        return block_write_full_page(page,get_block,wbc);
+}
+static int sysv_readpage(struct file *file, struct page *page)
+{
+        return block_read_full_page(page,get_block);
+}
+static int sysv_prepare_write(struct file *file, struct page *page, unsigned from, unsigned to)
+{
+        return block_prepare_write(page,from,to,get_block);
+}
+static sector_t sysv_bmap(struct address_space *mapping, sector_t block)
+{
+        return generic_block_bmap(mapping,block,get_block);
+}
+struct address_space_operations sysv_aops = {
+        .readpage = sysv_readpage,
+        .writepage = sysv_writepage,
+        .sync_page = block_sync_page,
+        .prepare_write = sysv_prepare_write,
+        .commit_write = generic_commit_write,
+        .bmap = sysv_bmap
+};