Linux文件系統omfs的普通文件創建和刪除

Omfs的普通文件的創建刪除與目錄創建刪除的動作非常類似，下面僅僅描述一下：

相關閱讀：Linux文件系統omfs的目錄創建和刪除 http://www.linuxidc.com/Linux/2012-02/54025.htm

在omfs_create處下斷點：

Breakpoint 3, omfs_create (dir=0xdde13c20, dentry=0xdf6f6440, mode=33188,

nd=0xddbe1eb8) at fs/omfs/dir.c:304

函數調用堆棧如下：

#0 omfs_create (dir=0xdde13c20, dentry=0xdf6f6440, mode=33188, nd=0xddbe1eb8)

at fs/omfs/dir.c:304

#1 0xc029e952 in vfs_create (dir=0xdde13c20, dentry=0xdf6f6440, mode=33188,

nd=0xddbe1eb8) at fs/namei.c:1418

#2 0xc029ebe5 in __open_namei_create (nd=0xddbe1eb8, path=0xddbe1f18,

open_flag=35137, mode=420) at fs/namei.c:1513

#3 0xc029f119 in do_last (nd=0xddbe1eb8, path=0xddbe1f18, open_flag=35137,

acc_mode=34, mode=438, pathname=0xd784f000 "aaaa") at fs/namei.c:1696

#4 0xc029f513 in do_filp_open (dfd=-100, pathname=0xd784f000 "aaaa",

open_flag=35137, mode=438, acc_mode=34) at fs/namei.c:1835

#5 0xc028f239 in do_sys_open (dfd=-100, filename=0xbfe8392a "aaaa",

flags=35137, mode=438) at fs/open.c:1052

#6 0xc028f2a7 in sys_open (filename=0xbfe8392a "aaaa", flags=35137, mode=438)

at fs/open.c:1073

#7 0xc0104657 in ?? () at arch/x86/kernel/entry_32.S:457

Omfs_createàomfs_add_node(dir, dentry, mode | S_IFREG);

區別如下：

在omfs_new_inode中：

switch (mode & S_IFMT) {

case S_IFDIR:

inode->i_op = &omfs_dir_inops;

inode->i_fop = &omfs_dir_operations;

inode->i_size = sbi->s_sys_blocksize;

inc_nlink(inode);

break;

case S_IFREG:

inode->i_op = &omfs_file_inops;

inode->i_fop = &omfs_file_operations;

inode->i_size = 0;

break;

}

在omfs_make_empty中：

if (inode->i_mode & S_IFDIR) {

memset(&bh->b_data[OMFS_DIR_START], 0xff,

sbi->s_sys_blocksize - OMFS_DIR_START);

} else

omfs_make_empty_table(bh, OMFS_EXTENT_START);

#define OMFS_EXTENT_START 0x1d0

對於文件的inode，我們會在inode中寫入omfs_extent信息：

oe->e_next = ~cpu_to_be64(0ULL);

oe->e_extent_count = cpu_to_be32(1),

oe->e_fill = cpu_to_be32(0x22),

oe->e_entry.e_cluster = ~cpu_to_be64(0ULL);

oe->e_entry.e_blocks = ~cpu_to_be64(0ULL);