Linux-2.6.12-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, 1169 insertions, 0 deletions

diff --git a/fs/reiserfs/bitmap.c b/fs/reiserfs/bitmap.c
new file mode 100644
index 000000000000..a4e2ed544bbe
--- /dev/null
+++ b/fs/reiserfs/bitmap.c
@@ -0,0 +1,1169 @@
+/*
+ * Copyright 2000 by Hans Reiser, licensing governed by reiserfs/README
+ */
+/* Reiserfs block (de)allocator, bitmap-based. */
+
+#include <linux/config.h>
+#include <linux/time.h>
+#include <linux/reiserfs_fs.h>
+#include <linux/errno.h>
+#include <linux/buffer_head.h>
+#include <linux/kernel.h>
+#include <linux/pagemap.h>
+#include <linux/reiserfs_fs_sb.h>
+#include <linux/reiserfs_fs_i.h>
+#include <linux/quotaops.h>
+
+#define PREALLOCATION_SIZE 9
+
+/* different reiserfs block allocator options */
+
+#define SB_ALLOC_OPTS(s) (REISERFS_SB(s)->s_alloc_options.bits)
+
+#define  _ALLOC_concentrating_formatted_nodes 0
+#define  _ALLOC_displacing_large_files 1
+#define  _ALLOC_displacing_new_packing_localities 2
+#define  _ALLOC_old_hashed_relocation 3
+#define  _ALLOC_new_hashed_relocation 4
+#define  _ALLOC_skip_busy 5
+#define  _ALLOC_displace_based_on_dirid 6
+#define  _ALLOC_hashed_formatted_nodes 7
+#define  _ALLOC_old_way 8
+#define  _ALLOC_hundredth_slices 9
+#define  _ALLOC_dirid_groups 10
+#define  _ALLOC_oid_groups 11
+#define  _ALLOC_packing_groups 12
+
+#define  concentrating_formatted_nodes(s)	test_bit(_ALLOC_concentrating_formatted_nodes, &SB_ALLOC_OPTS(s))
+#define  displacing_large_files(s)		test_bit(_ALLOC_displacing_large_files, &SB_ALLOC_OPTS(s))
+#define  displacing_new_packing_localities(s)	test_bit(_ALLOC_displacing_new_packing_localities, &SB_ALLOC_OPTS(s))
+
+#define SET_OPTION(optname) \
+   do { \
+        reiserfs_warning(s, "reiserfs: option \"%s\" is set", #optname); \
+        set_bit(_ALLOC_ ## optname , &SB_ALLOC_OPTS(s)); \
+    } while(0)
+#define TEST_OPTION(optname, s) \
+    test_bit(_ALLOC_ ## optname , &SB_ALLOC_OPTS(s))
+
+static inline void get_bit_address (struct super_block * s,
+				    b_blocknr_t block, int * bmap_nr, int * offset)
+{
+    /* It is in the bitmap block number equal to the block
+     * number divided by the number of bits in a block. */
+    *bmap_nr = block / (s->s_blocksize << 3);
+    /* Within that bitmap block it is located at bit offset *offset. */
+    *offset = block & ((s->s_blocksize << 3) - 1 );
+    return;
+}
+
+#ifdef CONFIG_REISERFS_CHECK
+int is_reusable (struct super_block * s, b_blocknr_t block, int bit_value)
+{
+    int i, j;
+
+    if (block == 0 || block >= SB_BLOCK_COUNT (s)) {
+	reiserfs_warning (s, "vs-4010: is_reusable: block number is out of range %lu (%u)",
+			  block, SB_BLOCK_COUNT (s));
+	return 0;
+    }
+
+    /* it can't be one of the bitmap blocks */
+    for (i = 0; i < SB_BMAP_NR (s); i ++)
+	if (block == SB_AP_BITMAP (s)[i].bh->b_blocknr) {
+	    reiserfs_warning (s, "vs: 4020: is_reusable: "
+			      "bitmap block %lu(%u) can't be freed or reused",
+			      block, SB_BMAP_NR (s));
+	    return 0;
+	}
+  
+    get_bit_address (s, block, &i, &j);
+
+    if (i >= SB_BMAP_NR (s)) {
+	reiserfs_warning (s, "vs-4030: is_reusable: there is no so many bitmap blocks: "
+			  "block=%lu, bitmap_nr=%d", block, i);
+	return 0;
+    }
+
+    if ((bit_value == 0 && 
+         reiserfs_test_le_bit(j, SB_AP_BITMAP(s)[i].bh->b_data)) ||
+	(bit_value == 1 && 
+	 reiserfs_test_le_bit(j, SB_AP_BITMAP (s)[i].bh->b_data) == 0)) {
+	reiserfs_warning (s, "vs-4040: is_reusable: corresponding bit of block %lu does not "
+			  "match required value (i==%d, j==%d) test_bit==%d",
+		block, i, j, reiserfs_test_le_bit (j, SB_AP_BITMAP (s)[i].bh->b_data));
+
+	return 0;
+    }
+
+    if (bit_value == 0 && block == SB_ROOT_BLOCK (s)) {
+	reiserfs_warning (s, "vs-4050: is_reusable: this is root block (%u), "
+			  "it must be busy", SB_ROOT_BLOCK (s));
+	return 0;
+    }
+
+    return 1;
+}
+#endif /* CONFIG_REISERFS_CHECK */
+
+/* searches in journal structures for a given block number (bmap, off). If block
+   is found in reiserfs journal it suggests next free block candidate to test. */
+static inline  int is_block_in_journal (struct super_block * s, int bmap, int
+off, int *next)
+{
+    b_blocknr_t tmp;
+
+    if (reiserfs_in_journal (s, bmap, off, 1, &tmp)) {
+	if (tmp) {              /* hint supplied */
+	    *next = tmp;
+	    PROC_INFO_INC( s, scan_bitmap.in_journal_hint );
+	} else {
+	    (*next) = off + 1;          /* inc offset to avoid looping. */
+	    PROC_INFO_INC( s, scan_bitmap.in_journal_nohint );
+	}
+	PROC_INFO_INC( s, scan_bitmap.retry );
+	return 1;
+    }
+    return 0;
+}
+
+/* it searches for a window of zero bits with given minimum and maximum lengths in one bitmap
+ * block; */
+static int scan_bitmap_block (struct reiserfs_transaction_handle *th,
+			      int bmap_n, int *beg, int boundary, int min, int max, int unfm)
+{
+    struct super_block *s = th->t_super;
+    struct reiserfs_bitmap_info *bi=&SB_AP_BITMAP(s)[bmap_n];
+    int end, next;
+    int org = *beg;
+
+    BUG_ON (!th->t_trans_id);
+
+    RFALSE(bmap_n >= SB_BMAP_NR (s), "Bitmap %d is out of range (0..%d)",bmap_n, SB_BMAP_NR (s) - 1);
+    PROC_INFO_INC( s, scan_bitmap.bmap );
+/* this is unclear and lacks comments, explain how journal bitmaps
+   work here for the reader.  Convey a sense of the design here. What
+   is a window? */
+/* - I mean `a window of zero bits' as in description of this function - Zam. */
+  
+    if ( !bi ) {
+	reiserfs_warning (s, "NULL bitmap info pointer for bitmap %d", bmap_n);
+	return 0;
+    }
+    if (buffer_locked (bi->bh)) {
+       PROC_INFO_INC( s, scan_bitmap.wait );
+       __wait_on_buffer (bi->bh);
+    }
+
+    while (1) {
+	cont:
+	if (bi->free_count < min)
+		return 0; // No free blocks in this bitmap
+
+	/* search for a first zero bit -- beggining of a window */
+	*beg = reiserfs_find_next_zero_le_bit
+	        ((unsigned long*)(bi->bh->b_data), boundary, *beg);
+  
+	if (*beg + min > boundary) { /* search for a zero bit fails or the rest of bitmap block
+				      * cannot contain a zero window of minimum size */
+	    return 0;
+	}
+
+	if (unfm && is_block_in_journal(s,bmap_n, *beg, beg))
+	    continue;
+	/* first zero bit found; we check next bits */
+	for (end = *beg + 1;; end ++) {
+	    if (end >= *beg + max || end >= boundary || reiserfs_test_le_bit (end, bi->bh->b_data)) {
+		next = end;
+		break;
+	    }
+	    /* finding the other end of zero bit window requires looking into journal structures (in
+	     * case of searching for free blocks for unformatted nodes) */
+	    if (unfm && is_block_in_journal(s, bmap_n, end, &next))
+		break;
+	}
+
+	/* now (*beg) points to beginning of zero bits window,
+	 * (end) points to one bit after the window end */
+	if (end - *beg >= min) { /* it seems we have found window of proper size */
+	    int i;
+	    reiserfs_prepare_for_journal (s, bi->bh, 1);
+	    /* try to set all blocks used checking are they still free */
+	    for (i = *beg; i < end; i++) {
+		/* It seems that we should not check in journal again. */
+		if (reiserfs_test_and_set_le_bit (i, bi->bh->b_data)) {
+		    /* bit was set by another process
+		     * while we slept in prepare_for_journal() */
+		    PROC_INFO_INC( s, scan_bitmap.stolen );
+		    if (i >= *beg + min)	{ /* we can continue with smaller set of allocated blocks,
+					   * if length of this set is more or equal to `min' */
+			end = i;
+			break;
+		    }
+		    /* otherwise we clear all bit were set ... */
+		    while (--i >= *beg)
+			reiserfs_test_and_clear_le_bit (i, bi->bh->b_data);
+		    reiserfs_restore_prepared_buffer (s, bi->bh);
+		    *beg = org;
+		    /* ... and search again in current block from beginning */
+		    goto cont;	
+		}
+	    }
+	    bi->free_count -= (end - *beg);
+	    journal_mark_dirty (th, s, bi->bh);
+
+	    /* free block count calculation */
+	    reiserfs_prepare_for_journal (s, SB_BUFFER_WITH_SB(s), 1);
+	    PUT_SB_FREE_BLOCKS(s, SB_FREE_BLOCKS(s) - (end - *beg));
+	    journal_mark_dirty (th, s, SB_BUFFER_WITH_SB(s));
+
+	    return end - (*beg);
+	} else {
+	    *beg = next;
+	}
+    }
+}
+
+static int bmap_hash_id(struct super_block *s, u32 id) {
+    char * hash_in = NULL;
+    unsigned long hash;
+    unsigned bm;
+
+    if (id <= 2) {
+	bm = 1;
+    } else {
+        hash_in = (char *)(&id);
+        hash = keyed_hash(hash_in, 4);
+	bm = hash % SB_BMAP_NR(s);
+	if (!bm)
+	    bm = 1;
+    }
+    /* this can only be true when SB_BMAP_NR = 1 */
+    if (bm >= SB_BMAP_NR(s))
+    	bm = 0;
+    return bm;
+}
+
+/*
+ * hashes the id and then returns > 0 if the block group for the
+ * corresponding hash is full
+ */
+static inline int block_group_used(struct super_block *s, u32 id) {
+    int bm;
+    bm = bmap_hash_id(s, id);
+    if (SB_AP_BITMAP(s)[bm].free_count > ((s->s_blocksize << 3) * 60 / 100) ) {
+        return 0;
+    }
+    return 1;
+}
+
+/*
+ * the packing is returned in disk byte order
+ */
+u32 reiserfs_choose_packing(struct inode *dir) {
+    u32 packing;
+    if (TEST_OPTION(packing_groups, dir->i_sb)) {
+	u32 parent_dir = le32_to_cpu(INODE_PKEY(dir)->k_dir_id);
+	/*
+	 * some versions of reiserfsck expect packing locality 1 to be
+	 * special
+	 */
+	if (parent_dir == 1 || block_group_used(dir->i_sb,parent_dir))
+            packing = INODE_PKEY(dir)->k_objectid;
+        else
+            packing = INODE_PKEY(dir)->k_dir_id;
+    } else
+        packing = INODE_PKEY(dir)->k_objectid;
+    return packing;
+}
+  
+/* Tries to find contiguous zero bit window (given size) in given region of
+ * bitmap and place new blocks there. Returns number of allocated blocks. */
+static int scan_bitmap (struct reiserfs_transaction_handle *th,
+			b_blocknr_t *start, b_blocknr_t finish,
+			int min, int max, int unfm, unsigned long file_block)
+{
+    int nr_allocated=0;
+    struct super_block * s = th->t_super;
+    /* find every bm and bmap and bmap_nr in this file, and change them all to bitmap_blocknr
+     * - Hans, it is not a block number - Zam. */
+
+    int bm, off;
+    int end_bm, end_off;
+    int off_max = s->s_blocksize << 3;
+
+    BUG_ON (!th->t_trans_id);
+
+    PROC_INFO_INC( s, scan_bitmap.call ); 
+    if ( SB_FREE_BLOCKS(s) <= 0)
+	return 0; // No point in looking for more free blocks
+
+    get_bit_address (s, *start, &bm, &off);
+    get_bit_address (s, finish, &end_bm, &end_off);
+    if (bm > SB_BMAP_NR(s))
+        return 0;
+    if (end_bm > SB_BMAP_NR(s))
+        end_bm = SB_BMAP_NR(s);
+
+    /* When the bitmap is more than 10% free, anyone can allocate.
+     * When it's less than 10% free, only files that already use the
+     * bitmap are allowed. Once we pass 80% full, this restriction
+     * is lifted.
+     *
+     * We do this so that files that grow later still have space close to
+     * their original allocation. This improves locality, and presumably
+     * performance as a result.
+     *
+     * This is only an allocation policy and does not make up for getting a
+     * bad hint. Decent hinting must be implemented for this to work well.
+     */
+    if ( TEST_OPTION(skip_busy, s) && SB_FREE_BLOCKS(s) > SB_BLOCK_COUNT(s)/20 ) {
+	for (;bm < end_bm; bm++, off = 0) {
+	    if ( ( off && (!unfm || (file_block != 0))) || SB_AP_BITMAP(s)[bm].free_count > (s->s_blocksize << 3) / 10 )
+		nr_allocated = scan_bitmap_block(th, bm, &off, off_max, min, max, unfm);
+	    if (nr_allocated)
+		goto ret;
+        }
+	/* we know from above that start is a reasonable number */
+	get_bit_address (s, *start, &bm, &off);
+    }
+
+    for (;bm < end_bm; bm++, off = 0) {
+	nr_allocated = scan_bitmap_block(th, bm, &off, off_max, min, max, unfm);
+	if (nr_allocated)
+	    goto ret;
+    }
+
+    nr_allocated = scan_bitmap_block(th, bm, &off, end_off + 1, min, max, unfm);
+  
+ ret:
+    *start = bm * off_max + off;
+    return nr_allocated;
+
+}
+
+static void _reiserfs_free_block (struct reiserfs_transaction_handle *th,
+				  struct inode *inode, b_blocknr_t block,
+				  int for_unformatted)
+{
+    struct super_block * s = th->t_super;
+    struct reiserfs_super_block * rs;
+    struct buffer_head * sbh;
+    struct reiserfs_bitmap_info *apbi;
+    int nr, offset;
+
+    BUG_ON (!th->t_trans_id);
+
+    PROC_INFO_INC( s, free_block );
+
+    rs = SB_DISK_SUPER_BLOCK (s);
+    sbh = SB_BUFFER_WITH_SB (s);
+    apbi = SB_AP_BITMAP(s);
+
+    get_bit_address (s, block, &nr, &offset);
+
+    if (nr >= sb_bmap_nr (rs)) {
+	reiserfs_warning (s, "vs-4075: reiserfs_free_block: "
+			  "block %lu is out of range on %s",
+			  block, reiserfs_bdevname (s));
+	return;
+    }
+
+    reiserfs_prepare_for_journal(s, apbi[nr].bh, 1 ) ;
+
+    /* clear bit for the given block in bit map */
+    if (!reiserfs_test_and_clear_le_bit (offset, apbi[nr].bh->b_data)) {
+	reiserfs_warning (s, "vs-4080: reiserfs_free_block: "
+			  "free_block (%s:%lu)[dev:blocknr]: bit already cleared",
+			  reiserfs_bdevname (s), block);
+    }
+    apbi[nr].free_count ++;
+    journal_mark_dirty (th, s, apbi[nr].bh);
+
+    reiserfs_prepare_for_journal(s, sbh, 1) ;
+    /* update super block */
+    set_sb_free_blocks( rs, sb_free_blocks(rs) + 1 );
+
+    journal_mark_dirty (th, s, sbh);
+    if (for_unformatted)
+        DQUOT_FREE_BLOCK_NODIRTY(inode, 1);
+}
+
+void reiserfs_free_block (struct reiserfs_transaction_handle *th, 
+			  struct inode *inode, b_blocknr_t block,
+			  int for_unformatted)
+{
+    struct super_block * s = th->t_super;
+
+    BUG_ON (!th->t_trans_id);
+
+    RFALSE(!s, "vs-4061: trying to free block on nonexistent device");
+    RFALSE(is_reusable (s, block, 1) == 0, "vs-4071: can not free such block");
+    /* mark it before we clear it, just in case */
+    journal_mark_freed(th, s, block) ;
+    _reiserfs_free_block(th, inode, block, for_unformatted) ;
+}
+
+/* preallocated blocks don't need to be run through journal_mark_freed */
+static void reiserfs_free_prealloc_block (struct reiserfs_transaction_handle *th,
+			  struct inode *inode, b_blocknr_t block) {
+    RFALSE(!th->t_super, "vs-4060: trying to free block on nonexistent device");
+    RFALSE(is_reusable (th->t_super, block, 1) == 0, "vs-4070: can not free such block");
+    BUG_ON (!th->t_trans_id);
+    _reiserfs_free_block(th, inode, block, 1) ;
+}
+
+static void __discard_prealloc (struct reiserfs_transaction_handle * th,
+				struct reiserfs_inode_info *ei)
+{
+    unsigned long save = ei->i_prealloc_block ;
+    int dirty = 0;
+    struct inode *inode = &ei->vfs_inode;
+    BUG_ON (!th->t_trans_id);
+#ifdef CONFIG_REISERFS_CHECK
+    if (ei->i_prealloc_count < 0)
+	reiserfs_warning (th->t_super, "zam-4001:%s: inode has negative prealloc blocks count.", __FUNCTION__ );
+#endif
+    while (ei->i_prealloc_count > 0) {
+	reiserfs_free_prealloc_block(th, inode, ei->i_prealloc_block);
+	ei->i_prealloc_block++;
+	ei->i_prealloc_count --;
+	dirty = 1;
+    }
+    if (dirty)
+    	reiserfs_update_sd(th, inode);
+    ei->i_prealloc_block = save;
+    list_del_init(&(ei->i_prealloc_list));
+}
+
+/* FIXME: It should be inline function */
+void reiserfs_discard_prealloc (struct reiserfs_transaction_handle *th, 
+				struct inode *inode)
+{
+    struct reiserfs_inode_info *ei = REISERFS_I(inode);
+    BUG_ON (!th->t_trans_id);
+    if (ei->i_prealloc_count)
+	__discard_prealloc(th, ei);
+}
+
+void reiserfs_discard_all_prealloc (struct reiserfs_transaction_handle *th)
+{
+    struct list_head * plist = &SB_JOURNAL(th->t_super)->j_prealloc_list;
+
+    BUG_ON (!th->t_trans_id);
+
+    while (!list_empty(plist)) {
+	struct reiserfs_inode_info *ei;
+	ei = list_entry(plist->next, struct reiserfs_inode_info, i_prealloc_list);
+#ifdef CONFIG_REISERFS_CHECK
+	if (!ei->i_prealloc_count) {
+	    reiserfs_warning (th->t_super, "zam-4001:%s: inode is in prealloc list but has no preallocated blocks.", __FUNCTION__);
+	}
+#endif
+	__discard_prealloc(th, ei);
+    }
+}
+
+void reiserfs_init_alloc_options (struct super_block *s)
+{
+    set_bit (_ALLOC_skip_busy, &SB_ALLOC_OPTS(s));
+    set_bit (_ALLOC_dirid_groups, &SB_ALLOC_OPTS(s));
+    set_bit (_ALLOC_packing_groups, &SB_ALLOC_OPTS(s));
+}
+
+/* block allocator related options are parsed here */
+int reiserfs_parse_alloc_options(struct super_block * s, char * options)
+{
+    char * this_char, * value;
+
+    REISERFS_SB(s)->s_alloc_options.bits = 0; /* clear default settings */
+
+    while ( (this_char = strsep (&options, ":")) != NULL ) {
+	if ((value = strchr (this_char, '=')) != NULL)
+	    *value++ = 0;
+
+	if (!strcmp(this_char, "concentrating_formatted_nodes")) {
+	    int temp;
+	    SET_OPTION(concentrating_formatted_nodes);
+	    temp = (value && *value) ? simple_strtoul (value, &value, 0) : 10;
+	    if (temp <= 0 || temp > 100) {
+		REISERFS_SB(s)->s_alloc_options.border = 10;
+	    } else {
+		REISERFS_SB(s)->s_alloc_options.border = 100 / temp;
+	   }
+	    continue;
+	}
+	if (!strcmp(this_char, "displacing_large_files")) {
+	    SET_OPTION(displacing_large_files);
+	    REISERFS_SB(s)->s_alloc_options.large_file_size =
+		(value && *value) ? simple_strtoul (value, &value, 0) : 16;
+	    continue;
+	}
+	if (!strcmp(this_char, "displacing_new_packing_localities")) {
+	    SET_OPTION(displacing_new_packing_localities);
+	    continue;
+	};
+
+	if (!strcmp(this_char, "old_hashed_relocation")) {
+	    SET_OPTION(old_hashed_relocation);
+	    continue;
+	}
+
+	if (!strcmp(this_char, "new_hashed_relocation")) {
+	    SET_OPTION(new_hashed_relocation);
+	    continue;
+	}
+
+        if (!strcmp(this_char, "dirid_groups")) {
+	    SET_OPTION(dirid_groups);
+	    continue;
+        }
+        if (!strcmp(this_char, "oid_groups")) {
+	    SET_OPTION(oid_groups);
+	    continue;
+        }
+        if (!strcmp(this_char, "packing_groups")) {
+	    SET_OPTION(packing_groups);
+	    continue;
+        }
+	if (!strcmp(this_char, "hashed_formatted_nodes")) {
+	    SET_OPTION(hashed_formatted_nodes);
+	    continue;
+	}
+
+	if (!strcmp(this_char, "skip_busy")) {
+	    SET_OPTION(skip_busy);
+	    continue;
+	}
+
+	if (!strcmp(this_char, "hundredth_slices")) {
+	    SET_OPTION(hundredth_slices);
+	    continue;
+	}
+
+	if (!strcmp(this_char, "old_way")) {
+	    SET_OPTION(old_way);
+	    continue;
+	}
+
+	if (!strcmp(this_char, "displace_based_on_dirid")) {
+	    SET_OPTION(displace_based_on_dirid);
+	    continue;
+	}
+
+	if (!strcmp(this_char, "preallocmin")) {
+	    REISERFS_SB(s)->s_alloc_options.preallocmin =
+		(value && *value) ? simple_strtoul (value, &value, 0) : 4;
+	    continue;
+	}
+
+	if (!strcmp(this_char, "preallocsize")) {
+	    REISERFS_SB(s)->s_alloc_options.preallocsize =
+		(value && *value) ? simple_strtoul (value, &value, 0) : PREALLOCATION_SIZE;
+	    continue;
+	}
+
+	reiserfs_warning (s, "zam-4001: %s : unknown option - %s",
+			  __FUNCTION__ , this_char);
+	return 1;
+      }
+  
+    reiserfs_warning (s, "allocator options = [%08x]\n", SB_ALLOC_OPTS(s));
+    return 0;
+}
+  
+static inline void new_hashed_relocation (reiserfs_blocknr_hint_t * hint)
+{
+    char * hash_in;
+    if (hint->formatted_node) {
+	    hash_in = (char*)&hint->key.k_dir_id;
+    } else {
+	if (!hint->inode) {
+	    //hint->search_start = hint->beg;
+	    hash_in = (char*)&hint->key.k_dir_id;
+	} else 
+	    if ( TEST_OPTION(displace_based_on_dirid, hint->th->t_super))
+		hash_in = (char *)(&INODE_PKEY(hint->inode)->k_dir_id);
+	    else
+		hash_in = (char *)(&INODE_PKEY(hint->inode)->k_objectid);
+      }
+
+    hint->search_start = hint->beg + keyed_hash(hash_in, 4) % (hint->end - hint->beg);
+}
+
+/*
+ * Relocation based on dirid, hashing them into a given bitmap block
+ * files. Formatted nodes are unaffected, a seperate policy covers them
+ */
+static void
+dirid_groups (reiserfs_blocknr_hint_t *hint)
+{
+    unsigned long hash;
+    __u32 dirid = 0;
+    int bm = 0;
+    struct super_block *sb = hint->th->t_super;
+    if (hint->inode)
+	dirid = le32_to_cpu(INODE_PKEY(hint->inode)->k_dir_id);
+    else if (hint->formatted_node)
+        dirid = hint->key.k_dir_id;
+
+    if (dirid) {
+	bm = bmap_hash_id(sb, dirid);
+	hash = bm * (sb->s_blocksize << 3);
+	/* give a portion of the block group to metadata */
+	if (hint->inode)
+	    hash += sb->s_blocksize/2;
+	hint->search_start = hash;
+    }
+}
+
+/*
+ * Relocation based on oid, hashing them into a given bitmap block
+ * files. Formatted nodes are unaffected, a seperate policy covers them
+ */
+static void
+oid_groups (reiserfs_blocknr_hint_t *hint)
+{
+    if (hint->inode) {
+	unsigned long hash;
+	__u32 oid;
+	__u32 dirid;
+	int bm;
+
+	dirid = le32_to_cpu(INODE_PKEY(hint->inode)->k_dir_id);
+
+	/* keep the root dir and it's first set of subdirs close to
+	 * the start of the disk
+	 */
+	if (dirid <= 2)
+	    hash = (hint->inode->i_sb->s_blocksize << 3);
+	else {
+	    oid = le32_to_cpu(INODE_PKEY(hint->inode)->k_objectid);
+	    bm = bmap_hash_id(hint->inode->i_sb, oid);
+	    hash = bm * (hint->inode->i_sb->s_blocksize << 3);
+	}
+	hint->search_start = hash;
+    }
+}
+
+/* returns 1 if it finds an indirect item and gets valid hint info
+ * from it, otherwise 0
+ */
+static int get_left_neighbor(reiserfs_blocknr_hint_t *hint)
+{
+    struct path * path;
+    struct buffer_head * bh;
+    struct item_head * ih;
+    int pos_in_item;
+    __u32 * item;
+    int ret = 0;
+
+    if (!hint->path)		/* reiserfs code can call this function w/o pointer to path
+				 * structure supplied; then we rely on supplied search_start */
+	return 0;
+
+    path = hint->path;
+    bh = get_last_bh(path);
+    RFALSE( !bh, "green-4002: Illegal path specified to get_left_neighbor");
+    ih = get_ih(path);
+    pos_in_item = path->pos_in_item;
+    item = get_item (path);
+
+    hint->search_start = bh->b_blocknr;
+
+    if (!hint->formatted_node && is_indirect_le_ih (ih)) {
+	/* for indirect item: go to left and look for the first non-hole entry
+	   in the indirect item */
+	if (pos_in_item == I_UNFM_NUM (ih))
+	    pos_in_item--;
+//	    pos_in_item = I_UNFM_NUM (ih) - 1;
+	while (pos_in_item >= 0) {
+	    int t=get_block_num(item,pos_in_item);
+	    if (t) {
+		hint->search_start = t;
+		ret = 1;
+		break;
+	    }
+	    pos_in_item --;
+	}
+    }
+
+    /* does result value fit into specified region? */
+    return ret;
+}
+
+/* should be, if formatted node, then try to put on first part of the device
+   specified as number of percent with mount option device, else try to put
+   on last of device.  This is not to say it is good code to do so,
+   but the effect should be measured.  */
+static inline void set_border_in_hint(struct super_block *s, reiserfs_blocknr_hint_t *hint)
+{
+    b_blocknr_t border = SB_BLOCK_COUNT(s) / REISERFS_SB(s)->s_alloc_options.border;
+
+    if (hint->formatted_node)
+	hint->end = border - 1;
+    else
+	hint->beg = border;
+}
+
+static inline void displace_large_file(reiserfs_blocknr_hint_t *hint)
+{
+    if ( TEST_OPTION(displace_based_on_dirid, hint->th->t_super))
+	hint->search_start = hint->beg + keyed_hash((char *)(&INODE_PKEY(hint->inode)->k_dir_id), 4) % (hint->end - hint->beg);
+    else
+	hint->search_start = hint->beg + keyed_hash((char *)(&INODE_PKEY(hint->inode)->k_objectid), 4) % (hint->end - hint->beg);
+}
+
+static inline void hash_formatted_node(reiserfs_blocknr_hint_t *hint)
+{
+   char * hash_in;
+
+   if (!hint->inode)
+	hash_in = (char*)&hint->key.k_dir_id;
+    else if ( TEST_OPTION(displace_based_on_dirid, hint->th->t_super))
+	hash_in = (char *)(&INODE_PKEY(hint->inode)->k_dir_id);
+    else
+	hash_in = (char *)(&INODE_PKEY(hint->inode)->k_objectid);
+
+	hint->search_start = hint->beg + keyed_hash(hash_in, 4) % (hint->end - hint->beg);
+}
+
+static inline int this_blocknr_allocation_would_make_it_a_large_file(reiserfs_blocknr_hint_t *hint)
+{
+    return hint->block == REISERFS_SB(hint->th->t_super)->s_alloc_options.large_file_size;
+}
+
+#ifdef DISPLACE_NEW_PACKING_LOCALITIES
+static inline void displace_new_packing_locality (reiserfs_blocknr_hint_t *hint)
+{
+    struct reiserfs_key * key = &hint->key;
+
+    hint->th->displace_new_blocks = 0;
+    hint->search_start = hint->beg + keyed_hash((char*)(&key->k_objectid),4) % (hint->end - hint->beg);
+}
+  #endif
+
+static inline int old_hashed_relocation (reiserfs_blocknr_hint_t * hint)
+{
+    b_blocknr_t border;
+    u32 hash_in;
+    
+    if (hint->formatted_node || hint->inode == NULL) {
+	return 0;
+      }
+
+    hash_in = le32_to_cpu((INODE_PKEY(hint->inode))->k_dir_id);
+    border = hint->beg + (u32) keyed_hash(((char *) (&hash_in)), 4) % (hint->end - hint->beg - 1);
+    if (border > hint->search_start)
+	hint->search_start = border;
+
+    return 1;
+  }
+  
+static inline int old_way (reiserfs_blocknr_hint_t * hint)
+{
+    b_blocknr_t border;
+    
+    if (hint->formatted_node || hint->inode == NULL) {
+	return 0;
+    }
+  
+      border = hint->beg + le32_to_cpu(INODE_PKEY(hint->inode)->k_dir_id) % (hint->end  - hint->beg);
+    if (border > hint->search_start)
+	hint->search_start = border;
+
+    return 1;
+}
+
+static inline void hundredth_slices (reiserfs_blocknr_hint_t * hint)
+{
+    struct reiserfs_key * key = &hint->key;
+    b_blocknr_t slice_start;
+
+    slice_start = (keyed_hash((char*)(&key->k_dir_id),4) % 100) * (hint->end / 100);
+    if ( slice_start > hint->search_start || slice_start + (hint->end / 100) <= hint->search_start) {
+	hint->search_start = slice_start;
+    }
+}
+  
+static void determine_search_start(reiserfs_blocknr_hint_t *hint,
+					  int amount_needed)
+{
+    struct super_block *s = hint->th->t_super;
+    int unfm_hint;
+
+    hint->beg = 0;
+    hint->end = SB_BLOCK_COUNT(s) - 1;
+
+    /* This is former border algorithm. Now with tunable border offset */
+    if (concentrating_formatted_nodes(s))
+	set_border_in_hint(s, hint);
+
+#ifdef DISPLACE_NEW_PACKING_LOCALITIES
+    /* whenever we create a new directory, we displace it.  At first we will
+       hash for location, later we might look for a moderately empty place for
+       it */
+    if (displacing_new_packing_localities(s)
+	&& hint->th->displace_new_blocks) {
+	displace_new_packing_locality(hint);
+
+	/* we do not continue determine_search_start,
+	 * if new packing locality is being displaced */
+	return;
+    }				      
+#endif
+  
+    /* all persons should feel encouraged to add more special cases here and
+     * test them */
+
+    if (displacing_large_files(s) && !hint->formatted_node
+	&& this_blocknr_allocation_would_make_it_a_large_file(hint)) {
+	displace_large_file(hint);
+	return;
+    }
+
+    /* if none of our special cases is relevant, use the left neighbor in the
+       tree order of the new node we are allocating for */
+    if (hint->formatted_node && TEST_OPTION(hashed_formatted_nodes,s)) {
+        hash_formatted_node(hint);
+	return;
+    }
+
+    unfm_hint = get_left_neighbor(hint);
+
+    /* Mimic old block allocator behaviour, that is if VFS allowed for preallocation,
+       new blocks are displaced based on directory ID. Also, if suggested search_start
+       is less than last preallocated block, we start searching from it, assuming that
+       HDD dataflow is faster in forward direction */
+    if ( TEST_OPTION(old_way, s)) {
+	if (!hint->formatted_node) {
+	    if ( !reiserfs_hashed_relocation(s))
+		old_way(hint);
+	    else if (!reiserfs_no_unhashed_relocation(s))
+		old_hashed_relocation(hint);
+
+	    if ( hint->inode && hint->search_start < REISERFS_I(hint->inode)->i_prealloc_block)
+		hint->search_start = REISERFS_I(hint->inode)->i_prealloc_block;
+	}
+	return;
+    }
+
+    /* This is an approach proposed by Hans */
+    if ( TEST_OPTION(hundredth_slices, s) && ! (displacing_large_files(s) && !hint->formatted_node)) {
+	hundredth_slices(hint);
+	return;
+    }
+
+    /* old_hashed_relocation only works on unformatted */
+    if (!unfm_hint && !hint->formatted_node &&
+        TEST_OPTION(old_hashed_relocation, s))
+    {
+	old_hashed_relocation(hint);
+    }
+    /* new_hashed_relocation works with both formatted/unformatted nodes */
+    if ((!unfm_hint || hint->formatted_node) &&
+        TEST_OPTION(new_hashed_relocation, s))
+    {
+	new_hashed_relocation(hint);
+    }
+    /* dirid grouping works only on unformatted nodes */
+    if (!unfm_hint && !hint->formatted_node && TEST_OPTION(dirid_groups,s))
+    {
+        dirid_groups(hint);
+    }
+
+#ifdef DISPLACE_NEW_PACKING_LOCALITIES
+    if (hint->formatted_node && TEST_OPTION(dirid_groups,s))
+    {
+        dirid_groups(hint);
+    }
+#endif
+
+    /* oid grouping works only on unformatted nodes */
+    if (!unfm_hint && !hint->formatted_node && TEST_OPTION(oid_groups,s))
+    {
+        oid_groups(hint);
+    }
+    return;
+}
+
+static int determine_prealloc_size(reiserfs_blocknr_hint_t * hint)
+{
+    /* make minimum size a mount option and benchmark both ways */
+    /* we preallocate blocks only for regular files, specific size */
+    /* benchmark preallocating always and see what happens */
+
+    hint->prealloc_size = 0;
+
+    if (!hint->formatted_node && hint->preallocate) {
+	if (S_ISREG(hint->inode->i_mode)
+	    && hint->inode->i_size >= REISERFS_SB(hint->th->t_super)->s_alloc_options.preallocmin * hint->inode->i_sb->s_blocksize)
+	    hint->prealloc_size = REISERFS_SB(hint->th->t_super)->s_alloc_options.preallocsize - 1;
+    }
+    return CARRY_ON;
+}
+
+/* XXX I know it could be merged with upper-level function;
+   but may be result function would be too complex. */
+static inline int allocate_without_wrapping_disk (reiserfs_blocknr_hint_t * hint,
+					 b_blocknr_t * new_blocknrs,
+					 b_blocknr_t start, b_blocknr_t finish,
+					 int min,
+					 int amount_needed, int prealloc_size)
+{
+    int rest = amount_needed;
+    int nr_allocated;
+  
+    while (rest > 0 && start <= finish) {
+	nr_allocated = scan_bitmap (hint->th, &start, finish, min,
+				    rest + prealloc_size, !hint->formatted_node,
+				    hint->block);
+
+	if (nr_allocated == 0)	/* no new blocks allocated, return */
+	    break;
+	
+	/* fill free_blocknrs array first */
+	while (rest > 0 && nr_allocated > 0) {
+	    * new_blocknrs ++ = start ++;
+	    rest --; nr_allocated --;
+	}
+
+	/* do we have something to fill prealloc. array also ? */
+	if (nr_allocated > 0) {
+	    /* it means prealloc_size was greater that 0 and we do preallocation */
+	    list_add(&REISERFS_I(hint->inode)->i_prealloc_list,
+		     &SB_JOURNAL(hint->th->t_super)->j_prealloc_list);
+	    REISERFS_I(hint->inode)->i_prealloc_block = start;
+	    REISERFS_I(hint->inode)->i_prealloc_count = nr_allocated;
+	    break;
+	}
+    }
+
+    return (amount_needed - rest);
+}
+
+static inline int blocknrs_and_prealloc_arrays_from_search_start
+    (reiserfs_blocknr_hint_t *hint, b_blocknr_t *new_blocknrs, int amount_needed)
+{
+    struct super_block *s = hint->th->t_super;
+    b_blocknr_t start = hint->search_start;
+    b_blocknr_t finish = SB_BLOCK_COUNT(s) - 1;
+    int passno = 0;
+    int nr_allocated = 0;
+    int bigalloc = 0;
+
+    determine_prealloc_size(hint);
+    if (!hint->formatted_node) {
+        int quota_ret;
+#ifdef REISERQUOTA_DEBUG
+	reiserfs_debug (s, REISERFS_DEBUG_CODE, "reiserquota: allocating %d blocks id=%u", amount_needed, hint->inode->i_uid);
+#endif
+	quota_ret = DQUOT_ALLOC_BLOCK_NODIRTY(hint->inode, amount_needed);
+	if (quota_ret)    /* Quota exceeded? */
+	    return QUOTA_EXCEEDED;
+	if (hint->preallocate && hint->prealloc_size ) {
+#ifdef REISERQUOTA_DEBUG
+	    reiserfs_debug (s, REISERFS_DEBUG_CODE, "reiserquota: allocating (prealloc) %d blocks id=%u", hint->prealloc_size, hint->inode->i_uid);
+#endif
+	    quota_ret = DQUOT_PREALLOC_BLOCK_NODIRTY(hint->inode, hint->prealloc_size);
+	    if (quota_ret)
+		hint->preallocate=hint->prealloc_size=0;
+	}
+	/* for unformatted nodes, force large allocations */
+	bigalloc = amount_needed;
+    }
+
+    do {
+	/* in bigalloc mode, nr_allocated should stay zero until
+	 * the entire allocation is filled
+	 */
+	if (unlikely(bigalloc && nr_allocated)) {
+	    reiserfs_warning(s, "bigalloc is %d, nr_allocated %d\n",
+	    bigalloc, nr_allocated);
+	    /* reset things to a sane value */
+	    bigalloc = amount_needed - nr_allocated;
+	}
+	/*
+	 * try pass 0 and pass 1 looking for a nice big
+	 * contiguous allocation.  Then reset and look
+	 * for anything you can find.
+	 */
+	if (passno == 2 && bigalloc) {
+	    passno = 0;
+	    bigalloc = 0;
+	}
+	switch (passno++) {
+        case 0: /* Search from hint->search_start to end of disk */
+	    start = hint->search_start;
+	    finish = SB_BLOCK_COUNT(s) - 1;
+	    break;
+        case 1: /* Search from hint->beg to hint->search_start */
+	    start = hint->beg;
+	    finish = hint->search_start;
+	    break;
+	case 2: /* Last chance: Search from 0 to hint->beg */
+	    start = 0;
+	    finish = hint->beg;
+	    break;
+	default: /* We've tried searching everywhere, not enough space */
+	    /* Free the blocks */
+	    if (!hint->formatted_node) {
+#ifdef REISERQUOTA_DEBUG
+		reiserfs_debug (s, REISERFS_DEBUG_CODE, "reiserquota: freeing (nospace) %d blocks id=%u", amount_needed + hint->prealloc_size - nr_allocated, hint->inode->i_uid);
+#endif
+		DQUOT_FREE_BLOCK_NODIRTY(hint->inode, amount_needed + hint->prealloc_size - nr_allocated);     /* Free not allocated blocks */
+	    }
+  	    while (nr_allocated --)
+		reiserfs_free_block(hint->th, hint->inode, new_blocknrs[nr_allocated], !hint->formatted_node);
+
+	    return NO_DISK_SPACE;
+	}
+    } while ((nr_allocated += allocate_without_wrapping_disk (hint,
+			    new_blocknrs + nr_allocated, start, finish,
+			    bigalloc ? bigalloc : 1,
+			    amount_needed - nr_allocated,
+			    hint->prealloc_size))
+			< amount_needed);
+    if ( !hint->formatted_node &&
+         amount_needed + hint->prealloc_size >
+	 nr_allocated + REISERFS_I(hint->inode)->i_prealloc_count) {
+    /* Some of preallocation blocks were not allocated */
+#ifdef REISERQUOTA_DEBUG
+	reiserfs_debug (s, REISERFS_DEBUG_CODE, "reiserquota: freeing (failed prealloc) %d blocks id=%u", amount_needed + hint->prealloc_size - nr_allocated - REISERFS_I(hint->inode)->i_prealloc_count, hint->inode->i_uid);
+#endif
+	DQUOT_FREE_BLOCK_NODIRTY(hint->inode, amount_needed +
+	                         hint->prealloc_size - nr_allocated -
+				 REISERFS_I(hint->inode)->i_prealloc_count);
+    }
+
+    return CARRY_ON;
+}
+
+/* grab new blocknrs from preallocated list */
+/* return amount still needed after using them */
+static int use_preallocated_list_if_available (reiserfs_blocknr_hint_t *hint,
+					       b_blocknr_t *new_blocknrs, int amount_needed)
+{
+    struct inode * inode = hint->inode;
+
+    if (REISERFS_I(inode)->i_prealloc_count > 0) {
+	while (amount_needed) {
+
+	    *new_blocknrs ++ = REISERFS_I(inode)->i_prealloc_block ++;
+	    REISERFS_I(inode)->i_prealloc_count --;
+
+	    amount_needed --;
+
+	    if (REISERFS_I(inode)->i_prealloc_count <= 0) {
+		list_del(&REISERFS_I(inode)->i_prealloc_list);  
+		break;
+	    }
+	}
+      }
+    /* return amount still needed after using preallocated blocks */
+    return amount_needed;
+}
+
+int reiserfs_allocate_blocknrs(reiserfs_blocknr_hint_t *hint,
+			       b_blocknr_t * new_blocknrs, int amount_needed,
+			       int reserved_by_us /* Amount of blocks we have
+						      already reserved */)
+{
+    int initial_amount_needed = amount_needed;
+    int ret;
+    struct super_block *s = hint->th->t_super;
+
+    /* Check if there is enough space, taking into account reserved space */
+    if ( SB_FREE_BLOCKS(s) - REISERFS_SB(s)->reserved_blocks <
+	 amount_needed - reserved_by_us)
+        return NO_DISK_SPACE;
+    /* should this be if !hint->inode &&  hint->preallocate? */
+    /* do you mean hint->formatted_node can be removed ? - Zam */
+    /* hint->formatted_node cannot be removed because we try to access
+       inode information here, and there is often no inode assotiated with
+       metadata allocations - green */
+
+    if (!hint->formatted_node && hint->preallocate) {
+	amount_needed = use_preallocated_list_if_available
+	    (hint, new_blocknrs, amount_needed);
+	if (amount_needed == 0)	/* all blocknrs we need we got from
+                                   prealloc. list */
+	    return CARRY_ON;
+	new_blocknrs += (initial_amount_needed - amount_needed);
+    }
+
+    /* find search start and save it in hint structure */
+    determine_search_start(hint, amount_needed);
+    if (hint->search_start >= SB_BLOCK_COUNT(s))
+        hint->search_start = SB_BLOCK_COUNT(s) - 1;
+
+    /* allocation itself; fill new_blocknrs and preallocation arrays */
+    ret = blocknrs_and_prealloc_arrays_from_search_start
+	(hint, new_blocknrs, amount_needed);
+
+    /* we used prealloc. list to fill (partially) new_blocknrs array. If final allocation fails we
+     * need to return blocks back to prealloc. list or just free them. -- Zam (I chose second
+     * variant) */
+
+    if (ret != CARRY_ON) {
+	while (amount_needed ++ < initial_amount_needed) {
+	    reiserfs_free_block(hint->th, hint->inode, *(--new_blocknrs), 1);
+	}
+    }
+    return ret;
+}
+
+/* These 2 functions are here to provide blocks reservation to the rest of kernel */
+/* Reserve @blocks amount of blocks in fs pointed by @sb. Caller must make sure
+   there are actually this much blocks on the FS available */
+void reiserfs_claim_blocks_to_be_allocated( 
+				      struct super_block *sb, /* super block of
+							        filesystem where
+								blocks should be
+								reserved */
+				      int blocks /* How much to reserve */
+					  )
+{
+
+    /* Fast case, if reservation is zero - exit immediately. */
+    if ( !blocks )
+	return;
+
+    spin_lock(&REISERFS_SB(sb)->bitmap_lock);
+    REISERFS_SB(sb)->reserved_blocks += blocks;
+    spin_unlock(&REISERFS_SB(sb)->bitmap_lock);
+}
+
+/* Unreserve @blocks amount of blocks in fs pointed by @sb */
+void reiserfs_release_claimed_blocks( 
+				struct super_block *sb, /* super block of
+							  filesystem where
+							  blocks should be
+							  reserved */
+				int blocks /* How much to unreserve */
+					  )
+{
+
+    /* Fast case, if unreservation is zero - exit immediately. */
+    if ( !blocks )
+	return;
+
+    spin_lock(&REISERFS_SB(sb)->bitmap_lock);
+    REISERFS_SB(sb)->reserved_blocks -= blocks;
+    spin_unlock(&REISERFS_SB(sb)->bitmap_lock);
+    RFALSE( REISERFS_SB(sb)->reserved_blocks < 0, "amount of blocks reserved became zero?");
+}
+
+/* This function estimates how much pages we will be able to write to FS
+   used for reiserfs_file_write() purposes for now. */
+int reiserfs_can_fit_pages ( struct super_block *sb /* superblock of filesystem
+						       to estimate space */ )
+{
+	int space;
+
+	spin_lock(&REISERFS_SB(sb)->bitmap_lock);
+	space = (SB_FREE_BLOCKS(sb) - REISERFS_SB(sb)->reserved_blocks) >> ( PAGE_CACHE_SHIFT - sb->s_blocksize_bits);
+	spin_unlock(&REISERFS_SB(sb)->bitmap_lock);
+
+	return space>0?space:0;
+}