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Retire .write/.read file operations 

The .write/.read file operations callbacks can be retired since
support for .read_iter/.write_iter and .aio_read/.aio_write has
been added.  The vfs_write()/vfs_read() entry functions will
select the correct interface for the kernel.  This is desirable
because all VFS write/read operations now rely on common code.

This change also add the generic write checks to make sure that
ulimits are enforced correctly on write.

Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Chunwei Chen <david.chen@osnexus.com>
Closes #5587
Closes #5673
This commit is contained in:
Chunwei Chen 2017-01-27 10:43:39 -08:00 committed by Brian Behlendorf
parent 110470266d
commit 5070e5311c
3 changed files with 72 additions and 33 deletions
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21
config/kernel-vfs-rw-iterate.m4
View File

@ -25,3 +25,24 @@ AC_DEFUN([ZFS_AC_KERNEL_VFS_RW_ITERATE],
AC_MSG_RESULT(no)
])
])
dnl #
dnl # Linux 4.1.x API
dnl #
AC_DEFUN([ZFS_AC_KERNEL_GENERIC_WRITE_CHECKS],
[AC_MSG_CHECKING([whether generic_write_checks() takes kiocb])
ZFS_LINUX_TRY_COMPILE([
#include <linux/fs.h>
],[
struct kiocb *iocb = NULL;
struct iov_iter *iov = NULL;
generic_write_checks(iocb, iov);
],[
AC_MSG_RESULT(yes)
AC_DEFINE(HAVE_GENERIC_WRITE_CHECKS_KIOCB, 1,
[generic_write_checks() takes kiocb])
],[
AC_MSG_RESULT(no)
])
])

1
config/kernel.m4
View File

@ -102,6 +102,7 @@ AC_DEFUN([ZFS_AC_CONFIG_KERNEL], [
ZFS_AC_KERNEL_LSEEK_EXECUTE
ZFS_AC_KERNEL_VFS_ITERATE
ZFS_AC_KERNEL_VFS_RW_ITERATE
ZFS_AC_KERNEL_GENERIC_WRITE_CHECKS
ZFS_AC_KERNEL_KMAP_ATOMIC_ARGS
ZFS_AC_KERNEL_FOLLOW_DOWN_ONE
ZFS_AC_KERNEL_MAKE_REQUEST_FN

83
module/zfs/zpl_file.c
View File

@ -259,20 +259,6 @@ zpl_read_common(struct inode *ip, const char *buf, size_t len, loff_t *ppos,
flags, cr, 0));
}
static ssize_t
zpl_read(struct file *filp, char __user *buf, size_t len, loff_t *ppos)
{
cred_t *cr = CRED();
ssize_t read;
crhold(cr);
read = zpl_read_common(filp->f_mapping->host, buf, len, ppos,
UIO_USERSPACE, filp->f_flags, cr);
crfree(cr);
return (read);
}
static ssize_t
zpl_iter_read_common(struct kiocb *kiocb, const struct iovec *iovp,
unsigned long nr_segs, size_t count, uio_seg_t seg, size_t skip)
@ -310,7 +296,14 @@ static ssize_t
zpl_aio_read(struct kiocb *kiocb, const struct iovec *iovp,
unsigned long nr_segs, loff_t pos)
{
return (zpl_iter_read_common(kiocb, iovp, nr_segs, kiocb->ki_nbytes,
ssize_t ret;
size_t count;
ret = generic_segment_checks(iovp, &nr_segs, &count, VERIFY_WRITE);
if (ret)
return (ret);
return (zpl_iter_read_common(kiocb, iovp, nr_segs, count,
UIO_USERSPACE, 0));
}
#endif /* HAVE_VFS_RW_ITERATE */
@ -348,6 +341,7 @@ zpl_write_common_iovec(struct inode *ip, const struct iovec *iovp, size_t count,
return (wrote);
}
inline ssize_t
zpl_write_common(struct inode *ip, const char *buf, size_t len, loff_t *ppos,
uio_seg_t segment, int flags, cred_t *cr)
@ -361,20 +355,6 @@ zpl_write_common(struct inode *ip, const char *buf, size_t len, loff_t *ppos,
flags, cr, 0));
}
static ssize_t
zpl_write(struct file *filp, const char __user *buf, size_t len, loff_t *ppos)
{
cred_t *cr = CRED();
ssize_t wrote;
crhold(cr);
wrote = zpl_write_common(filp->f_mapping->host, buf, len, ppos,
UIO_USERSPACE, filp->f_flags, cr);
crfree(cr);
return (wrote);
}
static ssize_t
zpl_iter_write_common(struct kiocb *kiocb, const struct iovec *iovp,
unsigned long nr_segs, size_t count, uio_seg_t seg, size_t skip)
@ -395,16 +375,40 @@ zpl_iter_write_common(struct kiocb *kiocb, const struct iovec *iovp,
static ssize_t
zpl_iter_write(struct kiocb *kiocb, struct iov_iter *from)
{
size_t count;
ssize_t ret;
uio_seg_t seg = UIO_USERSPACE;
#ifndef HAVE_GENERIC_WRITE_CHECKS_KIOCB
struct file *file = kiocb->ki_filp;
struct address_space *mapping = file->f_mapping;
struct inode *ip = mapping->host;
int isblk = S_ISBLK(ip->i_mode);
count = iov_iter_count(from);
ret = generic_write_checks(file, &kiocb->ki_pos, &count, isblk);
#else
/*
* XXX - ideally this check should be in the same lock region with
* write operations, so that there's no TOCTTOU race when doing
* append and someone else grow the file.
*/
ret = generic_write_checks(kiocb, from);
count = ret;
#endif
if (ret <= 0)
return (ret);
if (from->type & ITER_KVEC)
seg = UIO_SYSSPACE;
if (from->type & ITER_BVEC)
seg = UIO_BVEC;
ret = zpl_iter_write_common(kiocb, from->iov, from->nr_segs,
iov_iter_count(from), seg, from->iov_offset);
count, seg, from->iov_offset);
if (ret > 0)
iov_iter_advance(from, ret);
return (ret);
}
#else
@ -412,7 +416,22 @@ static ssize_t
zpl_aio_write(struct kiocb *kiocb, const struct iovec *iovp,
unsigned long nr_segs, loff_t pos)
{
return (zpl_iter_write_common(kiocb, iovp, nr_segs, kiocb->ki_nbytes,
struct file *file = kiocb->ki_filp;
struct address_space *mapping = file->f_mapping;
struct inode *ip = mapping->host;
int isblk = S_ISBLK(ip->i_mode);
size_t count;
ssize_t ret;
ret = generic_segment_checks(iovp, &nr_segs, &count, VERIFY_READ);
if (ret)
return (ret);
ret = generic_write_checks(file, &pos, &count, isblk);
if (ret)
return (ret);
return (zpl_iter_write_common(kiocb, iovp, nr_segs, count,
UIO_USERSPACE, 0));
}
#endif /* HAVE_VFS_RW_ITERATE */
@ -834,8 +853,6 @@ const struct file_operations zpl_file_operations = {
.open = zpl_open,
.release = zpl_release,
.llseek = zpl_llseek,
.read = zpl_read,
.write = zpl_write,
#ifdef HAVE_VFS_RW_ITERATE
.read_iter = zpl_iter_read,
.write_iter = zpl_iter_write,