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);