2009-08-19 20:50:44

by Eric Sandeen

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Subject: [PATCH 2/2] ext4: use ext4_grpblk_t more extensively

unsigned short is potentially too small to track blocks within
a group; today it is safe due to restrictions in e2fsprogs but
we have _lo / _hi bits for group blocks with the intent to go
up to 32 bits, so clean this up now.

There are many more places where we use unsigned/int/unsigned int
to contain a group block but this should at least fix all the
short types.

I added a few comments to the struct ext4_group_info definition
as well.

Signed-off-by: Eric Sandeen <[email protected]>
---

diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 80cd0f7..0dbfc2f 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -1573,15 +1573,18 @@ static inline void ext4_update_i_disksize(struct inode *inode, loff_t newsize)
struct ext4_group_info {
unsigned long bb_state;
struct rb_root bb_free_root;
- unsigned short bb_first_free;
- unsigned short bb_free;
- unsigned short bb_fragments;
+ ext4_grpblk_t bb_first_free; /* first free block */
+ ext4_grpblk_t bb_free; /* total free blocks */
+ ext4_grpblk_t bb_fragments; /* nr of freespace fragments */
struct list_head bb_prealloc_list;
#ifdef DOUBLE_CHECK
void *bb_bitmap;
#endif
struct rw_semaphore alloc_sem;
- unsigned short bb_counters[];
+ ext4_grpblk_t bb_counters[]; /* Nr of free power-of-two-block
+ * regions, index is order.
+ * bb_counters[3] = 5 means
+ * 5 free 8-block regions. */
};

#define EXT4_GROUP_INFO_NEED_INIT_BIT 0
diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 1b99c03..36eafab 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -622,13 +622,13 @@ static int __mb_check_buddy(struct ext4_buddy *e4b, char *file,

/* FIXME!! need more doc */
static void ext4_mb_mark_free_simple(struct super_block *sb,
- void *buddy, unsigned first, int len,
+ void *buddy, ext4_grpblk_t first, ext4_grpblk_t len,
struct ext4_group_info *grp)
{
struct ext4_sb_info *sbi = EXT4_SB(sb);
- unsigned short min;
- unsigned short max;
- unsigned short chunk;
+ ext4_grpblk_t min;
+ ext4_grpblk_t max;
+ ext4_grpblk_t chunk;
unsigned short border;

BUG_ON(len > EXT4_BLOCKS_PER_GROUP(sb));
@@ -662,10 +662,10 @@ void ext4_mb_generate_buddy(struct super_block *sb,
void *buddy, void *bitmap, ext4_group_t group)
{
struct ext4_group_info *grp = ext4_get_group_info(sb, group);
- unsigned short max = EXT4_BLOCKS_PER_GROUP(sb);
- unsigned short i = 0;
- unsigned short first;
- unsigned short len;
+ ext4_grpblk_t max = EXT4_BLOCKS_PER_GROUP(sb);
+ ext4_grpblk_t i = 0;
+ ext4_grpblk_t first;
+ ext4_grpblk_t len;
unsigned free = 0;
unsigned fragments = 0;
unsigned long long period = get_cycles();
@@ -2329,7 +2329,7 @@ static int ext4_mb_seq_groups_show(struct seq_file *seq, void *v)
struct ext4_buddy e4b;
struct sg {
struct ext4_group_info info;
- unsigned short counters[16];
+ ext4_grpblk_t counters[16];
} sg;

group--;
diff --git a/fs/ext4/mballoc.h b/fs/ext4/mballoc.h
index c96bb19..02a5079 100644
--- a/fs/ext4/mballoc.h
+++ b/fs/ext4/mballoc.h
@@ -128,8 +128,8 @@ struct ext4_prealloc_space {
unsigned pa_deleted;
ext4_fsblk_t pa_pstart; /* phys. block */
ext4_lblk_t pa_lstart; /* log. block */
- unsigned short pa_len; /* len of preallocated chunk */
- unsigned short pa_free; /* how many blocks are free */
+ ext4_grpblk_t pa_len; /* len of preallocated chunk */
+ ext4_grpblk_t pa_free; /* how many blocks are free */
unsigned short pa_type; /* pa type. inode or group */
spinlock_t *pa_obj_lock;
struct inode *pa_inode; /* hack, for history only */
@@ -144,7 +144,7 @@ struct ext4_free_extent {
ext4_lblk_t fe_logical;
ext4_grpblk_t fe_start;
ext4_group_t fe_group;
- int fe_len;
+ ext4_grpblk_t fe_len;
};

/*



2009-08-26 02:40:39

by Theodore Ts'o

[permalink] [raw]
Subject: Re: [PATCH 2/2] ext4: use ext4_grpblk_t more extensively

On Wed, Aug 19, 2009 at 03:19:42PM -0500, Eric Sandeen wrote:
> unsigned short is potentially too small to track blocks within
> a group; today it is safe due to restrictions in e2fsprogs but
> we have _lo / _hi bits for group blocks with the intent to go
> up to 32 bits, so clean this up now.

Thanks, applied.

- Ted