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Linux 5.10 compat: use iov_iter in uio structure #11351
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I'm not really familiar with this code, but I don't see any surface-level issues.
As of the 5.10 kernel the generic splice compatibility code has been removed. All filesystems are now responsible for registering a ->splice_read and ->splice_write callback to support this operation. The good news is the VFS provided generic_file_splice_read() and iter_file_splice_write() callbacks can be used provided the ->iter_read and ->iter_write callback support pipes. However, this is currently not the case and only iovecs and bvecs (not pipes) are ever attached to the uio structure. This commit changes that by allowing full iov_iter structures to be attached to uios. Ever since the 4.9 kernel the iov_iter structure has supported iovecs, kvecs, bvevs, and pipes so it's desirable to pass the entire thing when possible. In conjunction with this the uio helper functions (i.e uiomove(), uiocopy(), etc) have been updated to understand the new UIO_ITER type. Note that using the kernel provided uio_iter interfaces allowed the existing Linux specific uio handling code to be simplified. When there's no longer a need to support kernel's older than 4.9, then it will be possible to remove the iovec and bvec members from the uio structure and always use a uio_iter. Until then we need to maintain all of the existing types for older kernels. Some additional refactoring and cleanup was included in this change: - Added checks to configure to detect available iov_iter interfaces. Some are available all the way back to the 3.10 kernel and are used when available. In particular, uio_prefaultpages() now always uses iov_iter_fault_in_readable() which is available for all supported kernels. - The unused UIO_USERISPACE type has been removed. It is no longer needed now that the uio_seg enum is platform specific. - Moved zfs_uio.c from the zcommon.ko module to the Linux specific platform code for the zfs.ko module. This gets it out of libzfs where it was never needed and keeps this Linux specific code out of the common sources. - Removed unneccessary O_APPEND handling from zfs_iter_write(), this is redundant and O_APPEND is already handled in zfs_write(); Signed-off-by: Brian Behlendorf <[email protected]> Requires-builders: arch,style,amazon2,centos7,centos8,debian10,fedora33,ubuntu18,ubuntu20,builtin,freebsd12,freebsd13,coverage
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## master #11351 +/- ##
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- Coverage 76.77% 76.74% -0.04%
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Files 400 400
Lines 127825 127829 +4
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- Hits 98144 98099 -45
- Misses 29681 29730 +49
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This is a cherry-pick of 1c2358c from the master branch, backported to 0.8.6. Obviously, some file renaming and file splitting had to be undone. Also, the entire zfs_write_simple() function was pulled in from master. -MDL As of the 5.10 kernel the generic splice compatibility code has been removed. All filesystems are now responsible for registering a ->splice_read and ->splice_write callback to support this operation. The good news is the VFS provided generic_file_splice_read() and iter_file_splice_write() callbacks can be used provided the ->iter_read and ->iter_write callback support pipes. However, this is currently not the case and only iovecs and bvecs (not pipes) are ever attached to the uio structure. This commit changes that by allowing full iov_iter structures to be attached to uios. Ever since the 4.9 kernel the iov_iter structure has supported iovecs, kvecs, bvevs, and pipes so it's desirable to pass the entire thing when possible. In conjunction with this the uio helper functions (i.e uiomove(), uiocopy(), etc) have been updated to understand the new UIO_ITER type. Note that using the kernel provided uio_iter interfaces allowed the existing Linux specific uio handling code to be simplified. When there's no longer a need to support kernel's older than 4.9, then it will be possible to remove the iovec and bvec members from the uio structure and always use a uio_iter. Until then we need to maintain all of the existing types for older kernels. Some additional refactoring and cleanup was included in this change: - Added checks to configure to detect available iov_iter interfaces. Some are available all the way back to the 3.10 kernel and are used when available. In particular, uio_prefaultpages() now always uses iov_iter_fault_in_readable() which is available for all supported kernels. - The unused UIO_USERISPACE type has been removed. It is no longer needed now that the uio_seg enum is platform specific. - Moved zfs_uio.c from the zcommon.ko module to the Linux specific platform code for the zfs.ko module. This gets it out of libzfs where it was never needed and keeps this Linux specific code out of the common sources. (This was undone for 0.8.6) - Removed unnecessary O_APPEND handling from zfs_iter_write(), this is redundant and O_APPEND is already handled in zfs_write(); Reviewed-by: Colin Ian King <[email protected]> Reviewed-by: Tony Hutter <[email protected]> Signed-off-by: Brian Behlendorf <[email protected]> Closes openzfs#11351
As of the 5.10 kernel the generic splice compatibility code has been removed. All filesystems are now responsible for registering a ->splice_read and ->splice_write callback to support this operation. The good news is the VFS provided generic_file_splice_read() and iter_file_splice_write() callbacks can be used provided the ->iter_read and ->iter_write callback support pipes. However, this is currently not the case and only iovecs and bvecs (not pipes) are ever attached to the uio structure. This commit changes that by allowing full iov_iter structures to be attached to uios. Ever since the 4.9 kernel the iov_iter structure has supported iovecs, kvecs, bvevs, and pipes so it's desirable to pass the entire thing when possible. In conjunction with this the uio helper functions (i.e uiomove(), uiocopy(), etc) have been updated to understand the new UIO_ITER type. Note that using the kernel provided uio_iter interfaces allowed the existing Linux specific uio handling code to be simplified. When there's no longer a need to support kernel's older than 4.9, then it will be possible to remove the iovec and bvec members from the uio structure and always use a uio_iter. Until then we need to maintain all of the existing types for older kernels. Some additional refactoring and cleanup was included in this change: - Added checks to configure to detect available iov_iter interfaces. Some are available all the way back to the 3.10 kernel and are used when available. In particular, uio_prefaultpages() now always uses iov_iter_fault_in_readable() which is available for all supported kernels. - The unused UIO_USERISPACE type has been removed. It is no longer needed now that the uio_seg enum is platform specific. - Moved zfs_uio.c from the zcommon.ko module to the Linux specific platform code for the zfs.ko module. This gets it out of libzfs where it was never needed and keeps this Linux specific code out of the common sources. - Removed unnecessary O_APPEND handling from zfs_iter_write(), this is redundant and O_APPEND is already handled in zfs_write(); NOTE: Cleanly applying this kernel compatibility change required applying the following commits. This makes the change larger than it absolutely needs to be, but the resulting code matches what's in the branch branch. This is both more tested and makes it easier to apply any future backports in this area. 7cf4cd8 Remove incorrect assertion 783be69 Reduce confusion in zfs_write af5626a Return EFAULT at the end of zfs_write() when set cc1f85b Simplify offset and length limit in zfs_write 9585538 Const some unchanging variables in zfs_write 86e74dc Remove redundant oid parameter to update_pages b3d723f Factor uid, gid, and projid out of loop in zfs_write 3d40b65 Share zfs_fsync, zfs_read, zfs_write, et al between Linux and FreeBSD Reviewed-by: Colin Ian King <[email protected]> Reviewed-by: Tony Hutter <[email protected]> Signed-off-by: Brian Behlendorf <[email protected]> Closes #11351
As of the 5.10 kernel the generic splice compatibility code has been removed. All filesystems are now responsible for registering a ->splice_read and ->splice_write callback to support this operation. The good news is the VFS provided generic_file_splice_read() and iter_file_splice_write() callbacks can be used provided the ->iter_read and ->iter_write callback support pipes. However, this is currently not the case and only iovecs and bvecs (not pipes) are ever attached to the uio structure. This commit changes that by allowing full iov_iter structures to be attached to uios. Ever since the 4.9 kernel the iov_iter structure has supported iovecs, kvecs, bvevs, and pipes so it's desirable to pass the entire thing when possible. In conjunction with this the uio helper functions (i.e uiomove(), uiocopy(), etc) have been updated to understand the new UIO_ITER type. Note that using the kernel provided uio_iter interfaces allowed the existing Linux specific uio handling code to be simplified. When there's no longer a need to support kernel's older than 4.9, then it will be possible to remove the iovec and bvec members from the uio structure and always use a uio_iter. Until then we need to maintain all of the existing types for older kernels. Some additional refactoring and cleanup was included in this change: - Added checks to configure to detect available iov_iter interfaces. Some are available all the way back to the 3.10 kernel and are used when available. In particular, uio_prefaultpages() now always uses iov_iter_fault_in_readable() which is available for all supported kernels. - The unused UIO_USERISPACE type has been removed. It is no longer needed now that the uio_seg enum is platform specific. - Moved zfs_uio.c from the zcommon.ko module to the Linux specific platform code for the zfs.ko module. This gets it out of libzfs where it was never needed and keeps this Linux specific code out of the common sources. - Removed unnecessary O_APPEND handling from zfs_iter_write(), this is redundant and O_APPEND is already handled in zfs_write(); Reviewed-by: Colin Ian King <[email protected]> Reviewed-by: Tony Hutter <[email protected]> Signed-off-by: Brian Behlendorf <[email protected]> Closes openzfs#11351
As of the 5.10 kernel the generic splice compatibility code has been removed. All filesystems are now responsible for registering a ->splice_read and ->splice_write callback to support this operation. The good news is the VFS provided generic_file_splice_read() and iter_file_splice_write() callbacks can be used provided the ->iter_read and ->iter_write callback support pipes. However, this is currently not the case and only iovecs and bvecs (not pipes) are ever attached to the uio structure. This commit changes that by allowing full iov_iter structures to be attached to uios. Ever since the 4.9 kernel the iov_iter structure has supported iovecs, kvecs, bvevs, and pipes so it's desirable to pass the entire thing when possible. In conjunction with this the uio helper functions (i.e uiomove(), uiocopy(), etc) have been updated to understand the new UIO_ITER type. Note that using the kernel provided uio_iter interfaces allowed the existing Linux specific uio handling code to be simplified. When there's no longer a need to support kernel's older than 4.9, then it will be possible to remove the iovec and bvec members from the uio structure and always use a uio_iter. Until then we need to maintain all of the existing types for older kernels. Some additional refactoring and cleanup was included in this change: - Added checks to configure to detect available iov_iter interfaces. Some are available all the way back to the 3.10 kernel and are used when available. In particular, uio_prefaultpages() now always uses iov_iter_fault_in_readable() which is available for all supported kernels. - The unused UIO_USERISPACE type has been removed. It is no longer needed now that the uio_seg enum is platform specific. - Moved zfs_uio.c from the zcommon.ko module to the Linux specific platform code for the zfs.ko module. This gets it out of libzfs where it was never needed and keeps this Linux specific code out of the common sources. - Removed unnecessary O_APPEND handling from zfs_iter_write(), this is redundant and O_APPEND is already handled in zfs_write(); Reviewed-by: Colin Ian King <[email protected]> Reviewed-by: Tony Hutter <[email protected]> Signed-off-by: Brian Behlendorf <[email protected]> Closes openzfs#11351
Motivation and Context
Issue #11151, support for sendfile(2) with 5.10 kernel.
Description
As of the 5.10 kernel the generic splice compatibility code has been
removed. All filesystems are now responsible for registering a
->splice_read
and->splice_write
callback to support this operation.The good news is the VFS provided
generic_file_splice_read()
anditer_file_splice_write()
callbacks can be used provided the->iter_read
and
->iter_write
callback support pipes. However, this is currentlynot the case and only iovecs and bvecs (not pipes) are ever attached
to the uio structure.
This commit changes that by allowing full iov_iter structures to be
attached to uios. Ever since the 4.9 kernel the iov_iter structure
has supported iovecs, kvecs, bvevs, and pipes so it's desirable to
pass the entire thing when possible. In conjunction with this the
uio helper functions (i.e
uiomove()
,uiocopy()
, etc) have beenupdated to understand the new UIO_ITER type.
Note that using the kernel provided uio_iter interfaces allowed the
existing Linux specific uio handling code to be simplified. When
there's no longer a need to support kernel's older than 4.9, then
it will be possible to remove the iovec and bvec members from the
uio structure and always use a uio_iter. Until then we need to
maintain all of the existing types for older kernels.
Some additional refactoring and cleanup was included in this change:
Added checks to configure to detect available iov_iter interfaces.
Some are available all the way back to the 3.10 kernel and are used
when available. In particular, uio_prefaultpages() now always uses
iov_iter_fault_in_readable() which is available for all supported
kernels.
The unused UIO_USERISPACE type has been removed. It is no longer
needed now that the uio_seg enum is platform specific.
Moved zfs_uio.c from the zcommon.ko module to the Linux specific
platform code for the zfs.ko module. This gets it out of libzfs
where it was never needed and keeps this Linux specific code out
of the common sources.
Removed unnecessary O_APPEND handling from zfs_iter_write(), this
is redundant and O_APPEND is already handled in zfs_write();
How Has This Been Tested?
ZFS test suite run on:
Generic xfstest run on Ubuntu 20.10. All 60 tests passed.
Pending full ZTS on a wider assortment of kernels.
Types of changes
Checklist:
Signed-off-by
.