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Merged
merged 2 commits into from
Apr 17, 2016
Merged

Chengweiyu #26

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9877995
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WeiyuCheng Apr 16, 2016
8a8f585
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WeiyuCheng Apr 17, 2016
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64 changes: 55 additions & 9 deletions fs/hmfs/file.c
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Original file line number Diff line number Diff line change
Expand Up @@ -833,7 +833,7 @@ int truncate_data_blocks_range(struct dnode_of_data *dn, int count)
* in its parent indirect node to be NULL_ADDR
*/
/*
* 缩短dn指向的direct node中的数据
* 截断dn指向的direct node中的数据
* 检查dn->node_block中的每个地址指向的块是否为最新版本，若不是则删除无效块
* 再将删除后的有效块数量更新到inode和超级块中，并将inode标记为脏
*/
Expand All @@ -856,7 +856,11 @@ void truncate_data_blocks(struct dnode_of_data *dn)
mark_inode_dirty(dn->inode);
}
}

/*
* 将文件某个偏移量from所对应块在from之后的内容清零（只清除该块内容）
* @inode对应文件
* @from对应在文件中的偏移量
*/
static void truncate_partial_data_page(struct inode *inode, block_t from)
{
unsigned offset = from & (HMFS_PAGE_SIZE - 1);
Expand All @@ -867,7 +871,11 @@ static void truncate_partial_data_page(struct inode *inode, block_t from)
HMFS_PAGE_SIZE, true);
return;
}

/*
* 清除普通文件某个偏移量之后的全部内容
* @inode对应文件
* @from对应偏移量
*/
static int __truncate_blocks(struct inode *inode, block_t from)
{
struct dnode_of_data dn;
Expand Down Expand Up @@ -897,12 +905,22 @@ static int __truncate_blocks(struct inode *inode, block_t from)
}

free_next:
/*
* 先调用truncate_inode_blocks删除偏移量之后的所有块内容
* 再调用truncate_partial_data_page删除偏移量所在的块在其之后的内容
*/
err = truncate_inode_blocks(inode, free_from);
truncate_partial_data_page(inode, from);

return err;
}

/*
* 清除文件某个偏移量之后的全部内容
* @inode对应文件
* @from对应偏移量
* 若为内嵌型文件直接在本函数处理
* 否则调用__truncate_blocks处理普通文件
*/
static int truncate_blocks(struct inode *inode, block_t from)
{
struct hmfs_inode *inode_block;
Expand All @@ -919,7 +937,10 @@ static int truncate_blocks(struct inode *inode, block_t from)

return __truncate_blocks(inode, from);
}

/*
* 清除@inode对应文件在i_size之后的内容
* 再修改i_mtime及i_ctime并将inode标记为脏
*/
void hmfs_truncate(struct inode *inode)
{
if (!(S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode)
Expand Down Expand Up @@ -1325,7 +1346,12 @@ static long hmfs_fallocate(struct file *file, int mode, loff_t offset,

#define HMFS_REG_FLMASK (~(FS_DIRSYNC_FL | FS_TOPDIR_FL))
#define HMFS_OTHER_FLMASK (FS_NODUMP_FL | FS_NOATIME_FL)

/*
* 对于@flags进行掩码处理
* @mode对应目录文件时直接返回falgs
* @mode对应普通文件时返回flags & HMFS_REG_FLMASK
* 其他情况时返回flags & HMFS_OTHER_FLMASK
*/
static inline __u32 hmfs_mask_flags(umode_t mode, __u32 flags)
{
if (S_ISDIR(mode))
Expand All @@ -1335,7 +1361,15 @@ static inline __u32 hmfs_mask_flags(umode_t mode, __u32 flags)
else
return flags & HMFS_OTHER_FLMASK;
}

/*
* 向设备发送或接收控制信息
* @filp指向设备文件标识符
* @arg指向用户空间目标地址
* @cmd为HMFS_IOC_GETFLAGS时，将i_flags中用户可见位发送到用户空间目标地址
* @cmd为HMFS_IOC_SETFLAGS时，将用户空间目标地址的值复制到flags中
* @cmd为HMFS_IOC_GETVERSION时，将i_generation发送到用户空间目标地址
* 若不符合以上任何一种情况则返回-ENOTTY
*/
long hmfs_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
{
struct inode *inode = file_inode(filp);
Expand Down Expand Up @@ -1394,6 +1428,13 @@ long hmfs_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
}

#ifdef CONFIG_COMPAT
/*
* hmfs_ioctl函数的兼容性包装函数
* 向设备发送或接收控制信息
* @filp指向设备文件标识符
* @arg指向用户空间目标地址
* 调整@cmd的值再调用hmfs_ioctl发送或接收控制信息
*/
long hmfs_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
switch (cmd) {
Expand Down Expand Up @@ -1441,7 +1482,10 @@ const struct inode_operations hmfs_file_inode_operations = {
.removexattr = generic_removexattr,
#endif
};

/*
* 创建slab高速缓存，使mmap_block_slab指向缓存
* 成功返回0，失败返回-ENOMEM
*/
int create_mmap_struct_cache(void)
{
mmap_block_slab = hmfs_kmem_cache_create("hmfs_mmap_block",
Expand All @@ -1450,7 +1494,9 @@ int create_mmap_struct_cache(void)
return -ENOMEM;
return 0;
}

/*
* 销毁mmap_block_slab指向的slab高速缓存
*/
void destroy_mmap_struct_cache(void)
{
kmem_cache_destroy(mmap_block_slab);
Expand Down
11 changes: 10 additions & 1 deletion fs/hmfs/namei.c
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Original file line number Diff line number Diff line change
Expand Up @@ -371,6 +371,10 @@ int hmfs_getattr(struct vfsmount *mnt, struct dentry *dentry,
}

#ifdef CONFIG_HMFS_ACL
/*
* 更新@inode属性
* @attr指向存储要更新的属性的结构体
*/
static void __setattr_copy(struct inode *inode, const struct iattr *attr)
{
unsigned int ia_valid = attr->ia_valid;
Expand Down Expand Up @@ -398,7 +402,12 @@ static void __setattr_copy(struct inode *inode, const struct iattr *attr)
#else
#define __setattr_copy setattr_copy
#endif

/*
* 更新文件inode属性的包装函数
* 先判断inode权限决定是否可更新相应属性，再调用__setattr_copy更新属性
* @dentry指向对应文件inode
* @attr指向存储要更新的属性的结构体
*/
int hmfs_setattr(struct dentry *dentry, struct iattr *attr)
{
struct inode *inode = dentry->d_inode;
Expand Down