| Message ID | 20240123113333.79503-1-tony.solomonik@gmail.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | [v2,1/2] Add __do_ftruncate that truncates a struct file* | expand |
Tony Solomonik <tony.solomonik@gmail.com> writes: > do_sys_ftruncate receives a file descriptor, fgets the struct file*, and > finally actually truncates the file. This need to be Cc'ed to the VFS maintainers and appropriated lists. Also, you need a signed-off-by line and cover letter. Take a look at: https://www.kernel.org/doc/html/v6.7/process/submitting-patches.html > > __do_ftruncate allows for truncating a file without fgets. > --- > fs/open.c | 52 ++++++++++++++++++++++++---------------- > include/linux/syscalls.h | 2 ++ > 2 files changed, 33 insertions(+), 21 deletions(-) > > diff --git a/fs/open.c b/fs/open.c > index 02dc608d40d8..b32ac430666c 100644 > --- a/fs/open.c > +++ b/fs/open.c > @@ -154,47 +154,57 @@ COMPAT_SYSCALL_DEFINE2(truncate, const char __user *, path, compat_off_t, length > } > #endif > > -long do_sys_ftruncate(unsigned int fd, loff_t length, int small) > +long __do_ftruncate(struct file *file, loff_t length, int small) > { > struct inode *inode; > struct dentry *dentry; > - struct fd f; > int error; > > - error = -EINVAL; > - if (length < 0) > - goto out; > - error = -EBADF; > - f = fdget(fd); > - if (!f.file) > - goto out; > - > /* explicitly opened as large or we are on 64-bit box */ > - if (f.file->f_flags & O_LARGEFILE) > + if (file->f_flags & O_LARGEFILE) > small = 0; > > - dentry = f.file->f_path.dentry; > + dentry = file->f_path.dentry; > inode = dentry->d_inode; > error = -EINVAL; > - if (!S_ISREG(inode->i_mode) || !(f.file->f_mode & FMODE_WRITE)) > - goto out_putf; > + if (!S_ISREG(inode->i_mode) || !(file->f_mode & FMODE_WRITE)) > + goto out; Just return directly here. No point in jumping to 'out' just to return immediately. > > error = -EINVAL; > /* Cannot ftruncate over 2^31 bytes without large file support */ > if (small && length > MAX_NON_LFS) > - goto out_putf; > + goto out; likewise for the others.. > > error = -EPERM; > /* Check IS_APPEND on real upper inode */ > - if (IS_APPEND(file_inode(f.file))) > - goto out_putf; > + if (IS_APPEND(file_inode(file))) > + goto out; > sb_start_write(inode->i_sb); > - error = security_file_truncate(f.file); > + error = security_file_truncate(file); > if (!error) > - error = do_truncate(file_mnt_idmap(f.file), dentry, length, > - ATTR_MTIME | ATTR_CTIME, f.file); > + error = do_truncate(file_mnt_idmap(file), dentry, length, > + ATTR_MTIME | ATTR_CTIME, file); > sb_end_write(inode->i_sb); > -out_putf: > + > +out: > + return error; > +} > + > +long do_sys_ftruncate(unsigned int fd, loff_t length, int small) > +{ > + struct fd f; > + int error; > + > + error = -EINVAL; > + if (length < 0) > + goto out; > + error = -EBADF; > + f = fdget(fd); > + if (!f.file) > + goto out; > + > + error = __do_ftruncate(f.file, length, small); > + > fdput(f); > out: > return error; Same here. > diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h > index fd9d12de7e92..e8c56986e751 100644 > --- a/include/linux/syscalls.h > +++ b/include/linux/syscalls.h > @@ -1229,6 +1229,8 @@ static inline long ksys_lchown(const char __user *filename, uid_t user, > AT_SYMLINK_NOFOLLOW); > } > > +extern long __do_ftruncate(struct file *file, loff_t length, int small); > + > extern long do_sys_ftruncate(unsigned int fd, loff_t length, int small); > > static inline long ksys_ftruncate(unsigned int fd, loff_t length)
On 1/23/24 4:33 AM, Tony Solomonik wrote: > do_sys_ftruncate receives a file descriptor, fgets the struct file*, and > finally actually truncates the file. > > __do_ftruncate allows for truncating a file without fgets. > --- > fs/open.c | 52 ++++++++++++++++++++++++---------------- > include/linux/syscalls.h | 2 ++ > 2 files changed, 33 insertions(+), 21 deletions(-) > > diff --git a/fs/open.c b/fs/open.c > index 02dc608d40d8..b32ac430666c 100644 > --- a/fs/open.c > +++ b/fs/open.c > @@ -154,47 +154,57 @@ COMPAT_SYSCALL_DEFINE2(truncate, const char __user *, path, compat_off_t, length > } > #endif > > -long do_sys_ftruncate(unsigned int fd, loff_t length, int small) > +long __do_ftruncate(struct file *file, loff_t length, int small) > { > struct inode *inode; > struct dentry *dentry; > - struct fd f; > int error; > > - error = -EINVAL; > - if (length < 0) > - goto out; > - error = -EBADF; > - f = fdget(fd); > - if (!f.file) > - goto out; > - > /* explicitly opened as large or we are on 64-bit box */ > - if (f.file->f_flags & O_LARGEFILE) > + if (file->f_flags & O_LARGEFILE) > small = 0; > > - dentry = f.file->f_path.dentry; > + dentry = file->f_path.dentry; > inode = dentry->d_inode; > error = -EINVAL; > - if (!S_ISREG(inode->i_mode) || !(f.file->f_mode & FMODE_WRITE)) > - goto out_putf; > + if (!S_ISREG(inode->i_mode) || !(file->f_mode & FMODE_WRITE)) > + goto out; > > error = -EINVAL; > /* Cannot ftruncate over 2^31 bytes without large file support */ > if (small && length > MAX_NON_LFS) > - goto out_putf; > + goto out; > > error = -EPERM; > /* Check IS_APPEND on real upper inode */ > - if (IS_APPEND(file_inode(f.file))) > - goto out_putf; > + if (IS_APPEND(file_inode(file))) > + goto out; > sb_start_write(inode->i_sb); > - error = security_file_truncate(f.file); > + error = security_file_truncate(file); > if (!error) > - error = do_truncate(file_mnt_idmap(f.file), dentry, length, > - ATTR_MTIME | ATTR_CTIME, f.file); > + error = do_truncate(file_mnt_idmap(file), dentry, length, > + ATTR_MTIME | ATTR_CTIME, file); > sb_end_write(inode->i_sb); > -out_putf: > + > +out: > + return error; > +} > + > +long do_sys_ftruncate(unsigned int fd, loff_t length, int small) > +{ > + struct fd f; > + int error; > + > + error = -EINVAL; > + if (length < 0) > + goto out; > + error = -EBADF; > + f = fdget(fd); > + if (!f.file) > + goto out; > + > + error = __do_ftruncate(f.file, length, small); > + > fdput(f); > out: Same comments as Gabriel for the out label, just return error. > diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h > index fd9d12de7e92..e8c56986e751 100644 > --- a/include/linux/syscalls.h > +++ b/include/linux/syscalls.h > @@ -1229,6 +1229,8 @@ static inline long ksys_lchown(const char __user *filename, uid_t user, > AT_SYMLINK_NOFOLLOW); > } > > +extern long __do_ftruncate(struct file *file, loff_t length, int small); > + > extern long do_sys_ftruncate(unsigned int fd, loff_t length, int small); > > static inline long ksys_ftruncate(unsigned int fd, loff_t length) This should go in fs/internal.h, it's not a syscall related thing.
On 1/23/24 8:38 AM, Jens Axboe wrote: >> diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h >> index fd9d12de7e92..e8c56986e751 100644 >> --- a/include/linux/syscalls.h >> +++ b/include/linux/syscalls.h >> @@ -1229,6 +1229,8 @@ static inline long ksys_lchown(const char __user *filename, uid_t user, >> AT_SYMLINK_NOFOLLOW); >> } >> >> +extern long __do_ftruncate(struct file *file, loff_t length, int small); >> + >> extern long do_sys_ftruncate(unsigned int fd, loff_t length, int small); >> >> static inline long ksys_ftruncate(unsigned int fd, loff_t length) > > This should go in fs/internal.h, it's not a syscall related thing. And while at it, let's call it ftruncate_file() as that more accurately describes what it does.
diff --git a/fs/open.c b/fs/open.c index 02dc608d40d8..b32ac430666c 100644 --- a/fs/open.c +++ b/fs/open.c @@ -154,47 +154,57 @@ COMPAT_SYSCALL_DEFINE2(truncate, const char __user *, path, compat_off_t, length } #endif -long do_sys_ftruncate(unsigned int fd, loff_t length, int small) +long __do_ftruncate(struct file *file, loff_t length, int small) { struct inode *inode; struct dentry *dentry; - struct fd f; int error; - error = -EINVAL; - if (length < 0) - goto out; - error = -EBADF; - f = fdget(fd); - if (!f.file) - goto out; - /* explicitly opened as large or we are on 64-bit box */ - if (f.file->f_flags & O_LARGEFILE) + if (file->f_flags & O_LARGEFILE) small = 0; - dentry = f.file->f_path.dentry; + dentry = file->f_path.dentry; inode = dentry->d_inode; error = -EINVAL; - if (!S_ISREG(inode->i_mode) || !(f.file->f_mode & FMODE_WRITE)) - goto out_putf; + if (!S_ISREG(inode->i_mode) || !(file->f_mode & FMODE_WRITE)) + goto out; error = -EINVAL; /* Cannot ftruncate over 2^31 bytes without large file support */ if (small && length > MAX_NON_LFS) - goto out_putf; + goto out; error = -EPERM; /* Check IS_APPEND on real upper inode */ - if (IS_APPEND(file_inode(f.file))) - goto out_putf; + if (IS_APPEND(file_inode(file))) + goto out; sb_start_write(inode->i_sb); - error = security_file_truncate(f.file); + error = security_file_truncate(file); if (!error) - error = do_truncate(file_mnt_idmap(f.file), dentry, length, - ATTR_MTIME | ATTR_CTIME, f.file); + error = do_truncate(file_mnt_idmap(file), dentry, length, + ATTR_MTIME | ATTR_CTIME, file); sb_end_write(inode->i_sb); -out_putf: + +out: + return error; +} + +long do_sys_ftruncate(unsigned int fd, loff_t length, int small) +{ + struct fd f; + int error; + + error = -EINVAL; + if (length < 0) + goto out; + error = -EBADF; + f = fdget(fd); + if (!f.file) + goto out; + + error = __do_ftruncate(f.file, length, small); + fdput(f); out: return error; diff --git a/include/linux/syscalls.h b/include/linux/syscalls.h index fd9d12de7e92..e8c56986e751 100644 --- a/include/linux/syscalls.h +++ b/include/linux/syscalls.h @@ -1229,6 +1229,8 @@ static inline long ksys_lchown(const char __user *filename, uid_t user, AT_SYMLINK_NOFOLLOW); } +extern long __do_ftruncate(struct file *file, loff_t length, int small); + extern long do_sys_ftruncate(unsigned int fd, loff_t length, int small); static inline long ksys_ftruncate(unsigned int fd, loff_t length)