diff options
Diffstat (limited to 'fs/reiserfs/objectid.c')
| -rw-r--r-- | fs/reiserfs/objectid.c | 206 |
1 files changed, 206 insertions, 0 deletions
diff --git a/fs/reiserfs/objectid.c b/fs/reiserfs/objectid.c new file mode 100644 index 000000000000..0785c43a7486 --- /dev/null +++ b/fs/reiserfs/objectid.c @@ -0,0 +1,206 @@ +/* + * Copyright 2000 by Hans Reiser, licensing governed by reiserfs/README + */ + +#include <linux/config.h> +#include <linux/string.h> +#include <linux/random.h> +#include <linux/time.h> +#include <linux/reiserfs_fs.h> +#include <linux/reiserfs_fs_sb.h> + +// find where objectid map starts +#define objectid_map(s,rs) (old_format_only (s) ? \ + (__u32 *)((struct reiserfs_super_block_v1 *)(rs) + 1) :\ + (__u32 *)((rs) + 1)) + + +#ifdef CONFIG_REISERFS_CHECK + +static void check_objectid_map (struct super_block * s, __u32 * map) +{ + if (le32_to_cpu (map[0]) != 1) + reiserfs_panic (s, "vs-15010: check_objectid_map: map corrupted: %lx", + ( long unsigned int ) le32_to_cpu (map[0])); + + // FIXME: add something else here +} + +#else +static void check_objectid_map (struct super_block * s, __u32 * map) +{;} +#endif + + +/* When we allocate objectids we allocate the first unused objectid. + Each sequence of objectids in use (the odd sequences) is followed + by a sequence of objectids not in use (the even sequences). We + only need to record the last objectid in each of these sequences + (both the odd and even sequences) in order to fully define the + boundaries of the sequences. A consequence of allocating the first + objectid not in use is that under most conditions this scheme is + extremely compact. The exception is immediately after a sequence + of operations which deletes a large number of objects of + non-sequential objectids, and even then it will become compact + again as soon as more objects are created. Note that many + interesting optimizations of layout could result from complicating + objectid assignment, but we have deferred making them for now. */ + + +/* get unique object identifier */ +__u32 reiserfs_get_unused_objectid (struct reiserfs_transaction_handle *th) +{ + struct super_block * s = th->t_super; + struct reiserfs_super_block * rs = SB_DISK_SUPER_BLOCK (s); + __u32 * map = objectid_map (s, rs); + __u32 unused_objectid; + + BUG_ON (!th->t_trans_id); + + check_objectid_map (s, map); + + reiserfs_prepare_for_journal(s, SB_BUFFER_WITH_SB(s), 1) ; + /* comment needed -Hans */ + unused_objectid = le32_to_cpu (map[1]); + if (unused_objectid == U32_MAX) { + reiserfs_warning (s, "%s: no more object ids", __FUNCTION__); + reiserfs_restore_prepared_buffer(s, SB_BUFFER_WITH_SB(s)) ; + return 0; + } + + /* This incrementation allocates the first unused objectid. That + is to say, the first entry on the objectid map is the first + unused objectid, and by incrementing it we use it. See below + where we check to see if we eliminated a sequence of unused + objectids.... */ + map[1] = cpu_to_le32 (unused_objectid + 1); + + /* Now we check to see if we eliminated the last remaining member of + the first even sequence (and can eliminate the sequence by + eliminating its last objectid from oids), and can collapse the + first two odd sequences into one sequence. If so, then the net + result is to eliminate a pair of objectids from oids. We do this + by shifting the entire map to the left. */ + if (sb_oid_cursize(rs) > 2 && map[1] == map[2]) { + memmove (map + 1, map + 3, (sb_oid_cursize(rs) - 3) * sizeof(__u32)); + set_sb_oid_cursize( rs, sb_oid_cursize(rs) - 2 ); + } + + journal_mark_dirty(th, s, SB_BUFFER_WITH_SB (s)); + return unused_objectid; +} + + +/* makes object identifier unused */ +void reiserfs_release_objectid (struct reiserfs_transaction_handle *th, + __u32 objectid_to_release) +{ + struct super_block * s = th->t_super; + struct reiserfs_super_block * rs = SB_DISK_SUPER_BLOCK (s); + __u32 * map = objectid_map (s, rs); + int i = 0; + + BUG_ON (!th->t_trans_id); + //return; + check_objectid_map (s, map); + + reiserfs_prepare_for_journal(s, SB_BUFFER_WITH_SB(s), 1) ; + journal_mark_dirty(th, s, SB_BUFFER_WITH_SB (s)); + + /* start at the beginning of the objectid map (i = 0) and go to + the end of it (i = disk_sb->s_oid_cursize). Linear search is + what we use, though it is possible that binary search would be + more efficient after performing lots of deletions (which is + when oids is large.) We only check even i's. */ + while (i < sb_oid_cursize(rs)) { + if (objectid_to_release == le32_to_cpu (map[i])) { + /* This incrementation unallocates the objectid. */ + //map[i]++; + map[i] = cpu_to_le32 (le32_to_cpu (map[i]) + 1); + + /* Did we unallocate the last member of an odd sequence, and can shrink oids? */ + if (map[i] == map[i+1]) { + /* shrink objectid map */ + memmove (map + i, map + i + 2, + (sb_oid_cursize(rs) - i - 2) * sizeof (__u32)); + //disk_sb->s_oid_cursize -= 2; + set_sb_oid_cursize( rs, sb_oid_cursize(rs) - 2 ); + + RFALSE( sb_oid_cursize(rs) < 2 || + sb_oid_cursize(rs) > sb_oid_maxsize(rs), + "vs-15005: objectid map corrupted cur_size == %d (max == %d)", + sb_oid_cursize(rs), sb_oid_maxsize(rs)); + } + return; + } + + if (objectid_to_release > le32_to_cpu (map[i]) && + objectid_to_release < le32_to_cpu (map[i + 1])) { + /* size of objectid map is not changed */ + if (objectid_to_release + 1 == le32_to_cpu (map[i + 1])) { + //objectid_map[i+1]--; + map[i + 1] = cpu_to_le32 (le32_to_cpu (map[i + 1]) - 1); + return; + } + + /* JDM comparing two little-endian values for equality -- safe */ + if (sb_oid_cursize(rs) == sb_oid_maxsize(rs)) { + /* objectid map must be expanded, but there is no space */ + PROC_INFO_INC( s, leaked_oid ); + return; + } + + /* expand the objectid map*/ + memmove (map + i + 3, map + i + 1, + (sb_oid_cursize(rs) - i - 1) * sizeof(__u32)); + map[i + 1] = cpu_to_le32 (objectid_to_release); + map[i + 2] = cpu_to_le32 (objectid_to_release + 1); + set_sb_oid_cursize( rs, sb_oid_cursize(rs) + 2 ); + return; + } + i += 2; + } + + reiserfs_warning (s, "vs-15011: reiserfs_release_objectid: tried to free free object id (%lu)", + ( long unsigned ) objectid_to_release); +} + + +int reiserfs_convert_objectid_map_v1(struct super_block *s) { + struct reiserfs_super_block *disk_sb = SB_DISK_SUPER_BLOCK (s); + int cur_size = sb_oid_cursize(disk_sb); + int new_size = (s->s_blocksize - SB_SIZE) / sizeof(__u32) / 2 * 2 ; + int old_max = sb_oid_maxsize(disk_sb); + struct reiserfs_super_block_v1 *disk_sb_v1 ; + __u32 *objectid_map, *new_objectid_map ; + int i ; + + disk_sb_v1=(struct reiserfs_super_block_v1 *)(SB_BUFFER_WITH_SB(s)->b_data); + objectid_map = (__u32 *)(disk_sb_v1 + 1) ; + new_objectid_map = (__u32 *)(disk_sb + 1) ; + + if (cur_size > new_size) { + /* mark everyone used that was listed as free at the end of the objectid + ** map + */ + objectid_map[new_size - 1] = objectid_map[cur_size - 1] ; + set_sb_oid_cursize(disk_sb,new_size) ; + } + /* move the smaller objectid map past the end of the new super */ + for (i = new_size - 1 ; i >= 0 ; i--) { + objectid_map[i + (old_max - new_size)] = objectid_map[i] ; + } + + + /* set the max size so we don't overflow later */ + set_sb_oid_maxsize(disk_sb,new_size) ; + + /* Zero out label and generate random UUID */ + memset(disk_sb->s_label, 0, sizeof(disk_sb->s_label)) ; + generate_random_uuid(disk_sb->s_uuid); + + /* finally, zero out the unused chunk of the new super */ + memset(disk_sb->s_unused, 0, sizeof(disk_sb->s_unused)) ; + return 0 ; +} + |