diff options
| -rw-r--r-- | fs/gfs2/bmap.c | 68 |
1 files changed, 52 insertions, 16 deletions
diff --git a/fs/gfs2/bmap.c b/fs/gfs2/bmap.c index 7f72564e0597..6780aa5841b2 100644 --- a/fs/gfs2/bmap.c +++ b/fs/gfs2/bmap.c @@ -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 (new) { + map_bh(bh_map, inode->i_sb, dblock); + 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); - 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); - } } out_ok: error = 0; |
