[GFS2] Add a function to interate over an extent
This adds a function (currently the only use is during mapping of already allocated blocks, but watch this space) which iterates over a number of pointers in a block and returns the extent length. If the initial pointer is 0 (i.e. unallocated) it will return the number of unallocated blocks in the extent. If the initial pointer is allocated, then it returns the number of contiguously allocated blocks in the extent. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
This commit is contained in:
Родитель
c85a665f06
Коммит
30cbf189cd
|
@ -422,6 +422,42 @@ static void release_metapath(struct metapath *mp)
|
|||
brelse(mp->mp_bh[i]);
|
||||
}
|
||||
|
||||
/**
|
||||
* gfs2_extent_length - Returns length of an extent of blocks
|
||||
* @start: Start of the buffer
|
||||
* @len: Length of the buffer in bytes
|
||||
* @ptr: Current position in the buffer
|
||||
* @limit: Max extent length to return (0 = unlimited)
|
||||
* @eob: Set to 1 if we hit "end of block"
|
||||
*
|
||||
* If the first block is zero (unallocated) it will return the number of
|
||||
* unallocated blocks in the extent, otherwise it will return the number
|
||||
* of contiguous blocks in the extent.
|
||||
*
|
||||
* Returns: The length of the extent (minimum of one block)
|
||||
*/
|
||||
|
||||
static inline unsigned int gfs2_extent_length(void *start, unsigned int len, __be64 *ptr, unsigned limit, int *eob)
|
||||
{
|
||||
const __be64 *end = (start + len);
|
||||
const __be64 *first = ptr;
|
||||
u64 d = be64_to_cpu(*ptr);
|
||||
|
||||
*eob = 0;
|
||||
do {
|
||||
ptr++;
|
||||
if (ptr >= end)
|
||||
break;
|
||||
if (limit && --limit == 0)
|
||||
break;
|
||||
if (d)
|
||||
d++;
|
||||
} while(be64_to_cpu(*ptr) == d);
|
||||
if (ptr >= end)
|
||||
*eob = 1;
|
||||
return (ptr - first);
|
||||
}
|
||||
|
||||
static inline void bmap_lock(struct inode *inode, int create)
|
||||
{
|
||||
struct gfs2_inode *ip = GFS2_I(inode);
|
||||
|
@ -499,26 +535,26 @@ int gfs2_block_map(struct inode *inode, sector_t lblock,
|
|||
goto out_fail;
|
||||
boundary = error;
|
||||
|
||||
if (dblock) {
|
||||
if (new) {
|
||||
map_bh(bh_map, inode->i_sb, dblock);
|
||||
if (boundary)
|
||||
set_buffer_boundary(bh_map);
|
||||
if (new) {
|
||||
gfs2_trans_add_bh(ip->i_gl, mp.mp_bh[0], 1);
|
||||
gfs2_dinode_out(ip, mp.mp_bh[0]->b_data);
|
||||
set_buffer_new(bh_map);
|
||||
goto out_ok;
|
||||
}
|
||||
while(--maxlen && !buffer_boundary(bh_map)) {
|
||||
u64 eblock;
|
||||
mp.mp_list[ip->i_height - 1]++;
|
||||
boundary = lookup_block(ip, ip->i_height - 1, &mp, 0, &new, &eblock);
|
||||
if (eblock != ++dblock)
|
||||
break;
|
||||
bh_map->b_size += (1 << inode->i_blkbits);
|
||||
if (boundary)
|
||||
set_buffer_boundary(bh_map);
|
||||
}
|
||||
gfs2_trans_add_bh(ip->i_gl, mp.mp_bh[0], 1);
|
||||
gfs2_dinode_out(ip, mp.mp_bh[0]->b_data);
|
||||
set_buffer_new(bh_map);
|
||||
goto out_ok;
|
||||
}
|
||||
|
||||
if (dblock) {
|
||||
unsigned int len;
|
||||
struct buffer_head *bh = mp.mp_bh[ip->i_height - 1];
|
||||
__be64 *ptr = metapointer(&boundary, ip->i_height - 1, &mp);
|
||||
map_bh(bh_map, inode->i_sb, dblock);
|
||||
len = gfs2_extent_length(bh->b_data, bh->b_size, ptr, maxlen,
|
||||
&boundary);
|
||||
bh_map->b_size = (len << inode->i_blkbits);
|
||||
if (boundary)
|
||||
set_buffer_boundary(bh_map);
|
||||
}
|
||||
out_ok:
|
||||
error = 0;
|
||||
|
|
Загрузка…
Ссылка в новой задаче