diff options
Diffstat (limited to 'fs/ext4/namei.c')
| -rw-r--r-- | fs/ext4/namei.c | 39 |
1 files changed, 35 insertions, 4 deletions
diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c index 9468289637a5..5fdb862e71c4 100644 --- a/fs/ext4/namei.c +++ b/fs/ext4/namei.c @@ -140,7 +140,8 @@ struct dx_frame struct dx_map_entry { u32 hash; - u32 offs; + u16 offs; + u16 size; }; #ifdef CONFIG_EXT4_INDEX @@ -697,6 +698,10 @@ errout: * Directory block splitting, compacting */ +/* + * Create map of hash values, offsets, and sizes, stored at end of block. + * Returns number of entries mapped. + */ static int dx_make_map (struct ext4_dir_entry_2 *de, int size, struct dx_hash_info *hinfo, struct dx_map_entry *map_tail) { @@ -710,7 +715,8 @@ static int dx_make_map (struct ext4_dir_entry_2 *de, int size, ext4fs_dirhash(de->name, de->name_len, &h); map_tail--; map_tail->hash = h.hash; - map_tail->offs = (u32) ((char *) de - base); + map_tail->offs = (u16) ((char *) de - base); + map_tail->size = le16_to_cpu(de->rec_len); count++; cond_resched(); } @@ -720,6 +726,7 @@ static int dx_make_map (struct ext4_dir_entry_2 *de, int size, return count; } +/* Sort map by hash value */ static void dx_sort_map (struct dx_map_entry *map, unsigned count) { struct dx_map_entry *p, *q, *top = map + count - 1; @@ -1115,6 +1122,10 @@ static inline void ext4_set_de_type(struct super_block *sb, } #ifdef CONFIG_EXT4_INDEX +/* + * Move count entries from end of map between two memory locations. + * Returns pointer to last entry moved. + */ static struct ext4_dir_entry_2 * dx_move_dirents(char *from, char *to, struct dx_map_entry *map, int count) { @@ -1133,6 +1144,10 @@ dx_move_dirents(char *from, char *to, struct dx_map_entry *map, int count) return (struct ext4_dir_entry_2 *) (to - rec_len); } +/* + * Compact each dir entry in the range to the minimal rec_len. + * Returns pointer to last entry in range. + */ static struct ext4_dir_entry_2* dx_pack_dirents(char *base, int size) { struct ext4_dir_entry_2 *next, *to, *prev, *de = (struct ext4_dir_entry_2 *) base; @@ -1155,6 +1170,11 @@ static struct ext4_dir_entry_2* dx_pack_dirents(char *base, int size) return prev; } +/* + * Split a full leaf block to make room for a new dir entry. + * Allocate a new block, and move entries so that they are approx. equally full. + * Returns pointer to de in block into which the new entry will be inserted. + */ static struct ext4_dir_entry_2 *do_split(handle_t *handle, struct inode *dir, struct buffer_head **bh,struct dx_frame *frame, struct dx_hash_info *hinfo, int *error) @@ -1166,7 +1186,7 @@ static struct ext4_dir_entry_2 *do_split(handle_t *handle, struct inode *dir, u32 hash2; struct dx_map_entry *map; char *data1 = (*bh)->b_data, *data2; - unsigned split; + unsigned split, move, size, i; struct ext4_dir_entry_2 *de = NULL, *de2; int err = 0; @@ -1194,8 +1214,19 @@ static struct ext4_dir_entry_2 *do_split(handle_t *handle, struct inode *dir, count = dx_make_map ((struct ext4_dir_entry_2 *) data1, blocksize, hinfo, map); map -= count; - split = count/2; // need to adjust to actual middle dx_sort_map (map, count); + /* Split the existing block in the middle, size-wise */ + size = 0; + move = 0; + for (i = count-1; i >= 0; i--) { + /* is more than half of this entry in 2nd half of the block? */ + if (size + map[i].size/2 > blocksize/2) + break; + size += map[i].size; + move++; + } + /* map index at which we will split */ + split = count - move; hash2 = map[split].hash; continued = hash2 == map[split - 1].hash; dxtrace(printk("Split block %i at %x, %i/%i\n", |