On Thu, Nov 26, 2015 at 07:50:56PM +0100, Christoph Hellwig wrote:
> Pass a loff_t end for the last byte instead of the 32-bit count
> parameter to allow full file clones even on 32-bit architectures.
> While we're at it also drop the pointless inode argument and simplify
> the read/write selection.
>
> Signed-off-by: Christoph Hellwig <h...@lst.de>
> ---
> fs/locks.c | 22 +++++++++-------------
> fs/read_write.c | 5 ++---
> include/linux/fs.h | 28 +++++++++++++---------------
> 3 files changed, 24 insertions(+), 31 deletions(-)
>
> diff --git a/fs/locks.c b/fs/locks.c
> index 0d2b326..d503669 100644
> --- a/fs/locks.c
> +++ b/fs/locks.c
> @@ -1227,21 +1227,17 @@ int locks_mandatory_locked(struct file *file)
>
> /**
> * locks_mandatory_area - Check for a conflicting lock
> - * @read_write: %FLOCK_VERIFY_WRITE for exclusive access, %FLOCK_VERIFY_READ
> - * for shared
> - * @inode: the file to check
> * @filp: how the file was opened (if it was)
> - * @offset: start of area to check
> - * @count: length of area to check
> + * @start: first byte in the file to check
> + * @end: lastbyte in the file to check
> + * @write: %true if checking for write access
> *
> * Searches the inode's list of locks to find any POSIX locks which conflict.
> - * This function is called from rw_verify_area() and
> - * locks_verify_truncate().
> */
> -int locks_mandatory_area(int read_write, struct inode *inode,
> - struct file *filp, loff_t offset,
> - size_t count)
> +int locks_mandatory_area(struct file *filp, loff_t start, loff_t end,
> + bool write)
> {
> + struct inode *inode = file_inode(filp);
> struct file_lock fl;
> int error;
> bool sleep = false;
> @@ -1252,9 +1248,9 @@ int locks_mandatory_area(int read_write, struct inode
> *inode,
> fl.fl_flags = FL_POSIX | FL_ACCESS;
> if (filp && !(filp->f_flags & O_NONBLOCK))
> sleep = true;
> - fl.fl_type = (read_write == FLOCK_VERIFY_WRITE) ? F_WRLCK : F_RDLCK;
> - fl.fl_start = offset;
> - fl.fl_end = offset + count - 1;
> + fl.fl_type = write ? F_WRLCK : F_RDLCK;
> + fl.fl_start = start;
> + fl.fl_end = end;
>
> for (;;) {
> if (filp) {
> diff --git a/fs/read_write.c b/fs/read_write.c
> index c81ef39..48157dd 100644
> --- a/fs/read_write.c
> +++ b/fs/read_write.c
> @@ -396,9 +396,8 @@ int rw_verify_area(int read_write, struct file *file,
> const loff_t *ppos, size_t
> }
>
> if (unlikely(inode->i_flctx && mandatory_lock(inode))) {
> - retval = locks_mandatory_area(
> - read_write == READ ? FLOCK_VERIFY_READ :
> FLOCK_VERIFY_WRITE,
> - inode, file, pos, count);
> + retval = locks_mandatory_area(file, pos, pos + count - 1,
> + read_write == READ ? false : true);
> if (retval < 0)
> return retval;
> }
> diff --git a/include/linux/fs.h b/include/linux/fs.h
> index 870a76e..e640f791 100644
> --- a/include/linux/fs.h
> +++ b/include/linux/fs.h
> @@ -2030,12 +2030,9 @@ extern struct kobject *fs_kobj;
>
> #define MAX_RW_COUNT (INT_MAX & PAGE_CACHE_MASK)
>
> -#define FLOCK_VERIFY_READ 1
> -#define FLOCK_VERIFY_WRITE 2
> -
> #ifdef CONFIG_FILE_LOCKING
> extern int locks_mandatory_locked(struct file *);
> -extern int locks_mandatory_area(int, struct inode *, struct file *, loff_t,
> size_t);
> +extern int locks_mandatory_area(struct file *, loff_t, loff_t, bool);
>
> /*
> * Candidates for mandatory locking have the setgid bit set
> @@ -2068,14 +2065,16 @@ static inline int locks_verify_truncate(struct inode
> *inode,
> struct file *filp,
> loff_t size)
> {
> - if (inode->i_flctx && mandatory_lock(inode))
> - return locks_mandatory_area(
> - FLOCK_VERIFY_WRITE, inode, filp,
> - size < inode->i_size ? size : inode->i_size,
> - (size < inode->i_size ? inode->i_size - size
> - : size - inode->i_size)
> - );
> - return 0;
> + if (!inode->i_flctx || !mandatory_lock(inode))
> + return 0;
> +
> + if (size < inode->i_size) {
> + return locks_mandatory_area(filp, size, inode->i_size - 1,
> + true);
> + } else {
> + return locks_mandatory_area(filp, inode->i_size, size - 1,
> + true);
I feel like these callers would be just slightly more self-documenting
if that last parameter was F_WRLCK instead of true.
But I could live with it either way, patch looks like an
improvement--ACK.
--b.
> + }
> }
>
> static inline int break_lease(struct inode *inode, unsigned int mode)
> @@ -2144,9 +2143,8 @@ static inline int locks_mandatory_locked(struct file
> *file)
> return 0;
> }
>
> -static inline int locks_mandatory_area(int rw, struct inode *inode,
> - struct file *filp, loff_t offset,
> - size_t count)
> +static inline int locks_mandatory_area(struct file *filp, loff_t start,
> + loff_t end, bool write)
> {
> return 0;
> }
> --
> 1.9.1
>
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