Re: [U-Boot] [PATCH v3 04/13] ext4: Scan all directory blocks for space when inserting a new entry

Hi Stefan,

Previously, only the last directory block was scanned for available space. Instead, scan all blocks back to front, and if no sufficient space is found, eventually append a new block. Blocks are only appended if the directory does not use extents or the new block would require insertion of indirect blocks, as the old code does.

Signed-off-by: Stefan Brüns stefan.bruens@rwth-aachen.de

fs/ext4/ext4_common.c | 72 ++++++++++++++++++++------------------------------- 1 file changed, 28 insertions(+), 44 deletions(-)

v3: Patch added to series

diff --git a/fs/ext4/ext4_common.c b/fs/ext4/ext4_common.c index 49d6465..96dc371 100644 --- a/fs/ext4/ext4_common.c +++ b/fs/ext4/ext4_common.c @@ -365,14 +365,10 @@ int ext4fs_update_parent_dentry(char *filename, int file_type) { unsigned int *zero_buffer = NULL; char *root_first_block_buffer = NULL;

• int direct_blk_idx;
• long int root_blknr;

• int blk_idx; long int first_block_no_of_root = 0;

• long int previous_blknr = -1; int totalbytes = 0;
• short int padding_factor = 0; unsigned int new_entry_byte_reqd;
• unsigned int last_entry_dirlen; int sizeof_void_space = 0; int templength = 0; int inodeno = -1;

@@ -384,6 +380,7 @@ int ext4fs_update_parent_dentry(char *filename, int file_type) uint32_t new_blk_no; uint32_t new_size; uint32_t new_blockcnt;

• uint32_t directory_blocks;

  zero_buffer = zalloc(fs->blksz); if (!zero_buffer) {

@@ -396,19 +393,16 @@ int ext4fs_update_parent_dentry(char *filename, int file_type) printf("No Memory\n"); return -1; }

• new_entry_byte_reqd = ROUND(strlen(filename) +

• 		    sizeof(struct ext2_dirent), 4);
  

restart:

• directory_blocks = le32_to_cpu(g_parent_inode->size) >>

• LOG2_BLOCK_SIZE(ext4fs_root);
  

• blk_idx = directory_blocks - 1;

+restart_read: /* read the block no allocated to a file */

• for (direct_blk_idx = 0; direct_blk_idx < INDIRECT_BLOCKS;

•     direct_blk_idx++) {
  

• root_blknr = read_allocated_block(g_parent_inode,
  

• 				  direct_blk_idx);
  

• if (root_blknr == 0) {
  

• 	first_block_no_of_root = previous_blknr;
  

• 	break;
  

• }
  

• previous_blknr = root_blknr;
  

• }

• first_block_no_of_root =

read_allocated_block(g_parent_inode, blk_idx); status = ext4fs_devread((lbaint_t)first_block_no_of_root * fs->sect_perblk, @@ -420,42 +414,33 @@ restart: goto fail; dir = (struct ext2_dirent *)root_first_block_buffer; totalbytes = 0;

• while (le16_to_cpu(dir->direntlen) > 0) {

• /*
  

•  * blocksize-totalbytes because last directory length
  

•  * i.e. dir->direntlen is free availble space in the
  

•  * block that means  it is a last entry of directory
  

•  * entry
  

•  */
  

• unsigned short used_len = ROUND(dir->namelen +
  

•     sizeof(struct ext2_dirent), 4);
  
  

• /* traversing the each directory entry */
  

• /* last entry of block */
  

  if (fs->blksz - totalbytes ==

le16_to_cpu(dir->direntlen)) {

• 	if (strlen(filename) % 4 != 0)
  

• 		padding_factor = 4 -
  

(strlen(filename) % 4); -

• 	new_entry_byte_reqd = strlen(filename) +
  

• 	    sizeof(struct ext2_dirent) +
  

padding_factor;

• 	padding_factor = 0;
  

• 	/*
  

• 	 * update last directory entry length to its
  

• 	 * length because we are creating new
  

directory

• 	 * entry
  

• 	 */
  

• 	if (dir->namelen % 4 != 0)
  

• 		padding_factor = 4 - (dir->namelen %
  

4);

• 	last_entry_dirlen = dir->namelen +
  

• 	    sizeof(struct ext2_dirent) +
  

padding_factor;

• 	if ((fs->blksz - totalbytes -
  

last_entry_dirlen) <

• 		new_entry_byte_reqd) {
  

• 		printf("Last Block Full:Allocate new
  

block\n");

• 	/* check if new entry fits */
  

• 	if ((used_len + new_entry_byte_reqd) <=
  

• 	    le16_to_cpu(dir->direntlen)) {
  

• 		dir->direntlen =
  

cpu_to_le16(used_len);

• 		break;
  

• 	} else {
  

• 		if (blk_idx > 0) {
  

• 			printf("Block full, trying
  

previous\n");

• 			blk_idx--;
  

• 			goto restart_read;
  

• 		}
  

• 		printf("All blocks full: Allocate
  

new\n"); if (le32_to_cpu(g_parent_inode->flags) & EXT4_EXTENTS_FL) { printf("Directory uses extents\n"); goto fail; }

• 		if (direct_blk_idx ==
  

INDIRECT_BLOCKS - 1) {

• 		if (directory_blocks >=
  

INDIRECT_BLOCKS) { printf("Directory exceeds limit\n"); goto fail; } @@ -465,7 +450,8 @@ restart: goto fail; } put_ext4((uint64_t)new_blk_no * fs->blksz, zero_buffer, fs->blksz);

g_parent_inode->b.blocks.dir_blocks[direct_blk_idx] =

• 		g_parent_inode->b.blocks.
  

• 			dir_blocks[directory_blocks]
  

= cpu_to_le32(new_blk_no);

		new_size =

le32_to_cpu(g_parent_inode->size); @@ -482,8 +468,6 @@ restart: goto fail; goto restart; }

• 	dir->direntlen =
  

cpu_to_le16(last_entry_dirlen);

• 	break;
  

  }

  templength = le16_to_cpu(dir->direntlen);

Reviewed-by: Lukasz Majewski l.majewski@samsung.com