| Message ID | 20190326190301.32365-12-rgoldwyn@suse.de (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [01/15] btrfs: create a mount option for dax | expand |
On Tue, Mar 26, 2019 at 02:02:57PM -0500, Goldwyn Rodrigues wrote: > From: Goldwyn Rodrigues <rgoldwyn@suse.com> > > With dax we cannot deal with readpage() etc. So, we create a > funciton callback to perform the file data comparison and pass > it to generic_remap_file_range_prep() so it can use iomap-based > functions. So it occurs to me -- is there an intrinsic requirement that all files sharing blocks must be in DAX mode or not-DAX mode? Or in other words, if I run cp --reflink a b, then it cannot be the case that IS_DAX(a) != IS_DAX(b), right? Will there be calamitous consequences if dax and page cache both point to the same piece of storage? I would imagine so... > This may not be the best way to solve this. Suggestions welcome. Agree. There's a fair amount of code duplication between the dax and pagecache compare functions, considering that the loop structure for both cases is: while (len) { /* Figure out minimum comparison length */ /* Map source file range into memory */ /* Map dest file range into memory */ /* Compare memory */ /* Release dest file memory */ /* Release source file memory */ /* Update counters or break out */ } The current vfs_dedupe_file_range_compare could use some improvements, at least for filesystems where we actually support iomap. In particular, if you try to dedupe into or out of a hole, it'll flood the page cache with zero pages, which is pretty wasteful if we could've found out that it's actually a hole. > Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com> > --- > fs/btrfs/ctree.h | 3 +++ > fs/btrfs/dax.c | 7 +++++++ > fs/btrfs/ioctl.c | 13 +++++++++++- > fs/dax.c | 58 ++++++++++++++++++++++++++++++++++++++++++++++++++++ > fs/ocfs2/file.c | 2 +- > fs/read_write.c | 9 +++++--- > fs/xfs/xfs_reflink.c | 2 +- > include/linux/dax.h | 2 ++ > include/linux/fs.h | 4 +++- > 9 files changed, 93 insertions(+), 7 deletions(-) > > diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h > index 0e5060933bde..750f9c70fabe 100644 > --- a/fs/btrfs/ctree.h > +++ b/fs/btrfs/ctree.h > @@ -3803,6 +3803,9 @@ int btree_readahead_hook(struct extent_buffer *eb, int err); > ssize_t btrfs_file_dax_read(struct kiocb *iocb, struct iov_iter *to); > ssize_t btrfs_file_dax_write(struct kiocb *iocb, struct iov_iter *from); > vm_fault_t btrfs_dax_fault(struct vm_fault *vmf); > +int btrfs_dax_file_range_compare(struct inode *src, loff_t srcoff, > + struct inode *dest, loff_t destoff, loff_t len, > + bool *is_same); > #else > static inline ssize_t btrfs_file_dax_write(struct kiocb *iocb, struct iov_iter *from) > { > diff --git a/fs/btrfs/dax.c b/fs/btrfs/dax.c > index 927f962d1e88..9488cae0f8b4 100644 > --- a/fs/btrfs/dax.c > +++ b/fs/btrfs/dax.c > @@ -168,4 +168,11 @@ vm_fault_t btrfs_dax_fault(struct vm_fault *vmf) > > return ret; > } > + > +int btrfs_dax_file_range_compare(struct inode *src, loff_t srcoff, > + struct inode *dest, loff_t destoff, loff_t len, > + bool *is_same) > +{ > + return dax_file_range_compare(src, srcoff, dest, destoff, len, is_same, &btrfs_iomap_ops); > +} > #endif /* CONFIG_FS_DAX */ > diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c > index e66426e7692d..2e5137b01561 100644 > --- a/fs/btrfs/ioctl.c > +++ b/fs/btrfs/ioctl.c > @@ -3990,8 +3990,19 @@ static int btrfs_remap_file_range_prep(struct file *file_in, loff_t pos_in, > if (ret < 0) > goto out_unlock; > > +#ifdef CONFIG_FS_DAX > + if (IS_DAX(file_inode(file_in)) && IS_DAX(file_inode(file_out))) > + ret = generic_remap_file_range_prep(file_in, pos_in, file_out, > + pos_out, len, remap_flags, > + btrfs_dax_file_range_compare); > + else > + ret = generic_remap_file_range_prep(file_in, pos_in, file_out, > + pos_out, len, remap_flags, NULL); > +#else > ret = generic_remap_file_range_prep(file_in, pos_in, file_out, pos_out, > - len, remap_flags); > + len, remap_flags, NULL); > +#endif > + > if (ret < 0 || *len == 0) > goto out_unlock; > > diff --git a/fs/dax.c b/fs/dax.c > index 41061da42771..18998c5ee27a 100644 > --- a/fs/dax.c > +++ b/fs/dax.c > @@ -1775,3 +1775,61 @@ vm_fault_t dax_finish_sync_fault(struct vm_fault *vmf, > return dax_insert_pfn_mkwrite(vmf, pfn, order); > } > EXPORT_SYMBOL_GPL(dax_finish_sync_fault); > + > + > +int dax_file_range_compare(struct inode *src, loff_t srcoff, struct inode *dest, > + loff_t destoff, loff_t len, bool *is_same, const struct iomap_ops *ops) Comments for this function assume this is a vfs generic function, not a dax specific thing... > +{ > + void *saddr, *daddr; > + struct iomap s_iomap = {0}; > + struct iomap d_iomap = {0}; > + loff_t dstart, sstart; > + bool same = true; > + loff_t cmp_len, l; > + int id, ret = 0; > + > + id = dax_read_lock(); > + while (len) { > + ret = ops->iomap_begin(src, srcoff, len, 0, &s_iomap); > + if (ret < 0) { > + if (ops->iomap_end) > + ops->iomap_end(src, srcoff, len, ret, 0, &s_iomap); > + return ret; > + } Shouldn't we be checking that the iomap actually points to written storage? As opposed to hole/delalloc/unwritten? Bonus: not-written extents (hole/unwritten) could be optimized a bit, though I don't know if it's worth it for something that's probably a corner case. > + cmp_len = len; > + if (cmp_len > s_iomap.offset + s_iomap.length - srcoff) > + cmp_len = s_iomap.offset + s_iomap.length - srcoff; > + > + ret = ops->iomap_begin(dest, destoff, cmp_len, 0, &d_iomap); > + if (ret < 0) { > + if (ops->iomap_end) { > + ops->iomap_end(src, srcoff, len, ret, 0, &s_iomap); > + ops->iomap_end(dest, destoff, len, ret, 0, &d_iomap); > + } > + return ret; > + } > + if (cmp_len > d_iomap.offset + d_iomap.length - destoff) > + cmp_len = d_iomap.offset + d_iomap.length - destoff; > + If you wanted to make this a generic function, it would be kinda nice if we could switch between grabbing page cache for non-DAX files and dax_direct_access for DAX files. (Actually, no, that's kind of ugly too.) Perhaps iomap.c needs to grow a function to iterate ranges of two files and call an actor function on both sets? And we can change the actor to be the pagecache-grabbing one or the dax-access one depending on the DAX mode. Though I guess that leaves poor old ocfs2 in the dust since it doesn't support iomap. I guess it wouldn't be too hard to adapt it to have an iomap ops for reads only. > + > + sstart = (get_start_sect(s_iomap.bdev) << 9) + s_iomap.addr + (srcoff - s_iomap.offset); > + l = dax_direct_access(s_iomap.dax_dev, PHYS_PFN(sstart), PHYS_PFN(cmp_len), &saddr, NULL); > + dstart = (get_start_sect(d_iomap.bdev) << 9) + d_iomap.addr + (destoff - d_iomap.offset); > + l = dax_direct_access(d_iomap.dax_dev, PHYS_PFN(dstart), PHYS_PFN(cmp_len), &daddr, NULL); > + same = !memcmp(saddr, daddr, cmp_len); > + if (!same) > + break; > + len -= cmp_len; > + srcoff += cmp_len; > + destoff += cmp_len; > + > + if (ops->iomap_end) { > + ret = ops->iomap_end(src, srcoff, len, 0, 0, &s_iomap); > + ret = ops->iomap_end(dest, destoff, len, 0, 0, &d_iomap); > + } > + } > + dax_read_unlock(id); > + *is_same = same; > + return ret; > +} > +EXPORT_SYMBOL_GPL(dax_file_range_compare); > diff --git a/fs/ocfs2/file.c b/fs/ocfs2/file.c > index d640c5f8a85d..6bf3e8fbb016 100644 > --- a/fs/ocfs2/file.c > +++ b/fs/ocfs2/file.c > @@ -2558,7 +2558,7 @@ static loff_t ocfs2_remap_file_range(struct file *file_in, loff_t pos_in, > goto out_unlock; > > ret = generic_remap_file_range_prep(file_in, pos_in, file_out, pos_out, > - &len, remap_flags); > + &len, remap_flags, NULL); > if (ret < 0 || len == 0) > goto out_unlock; > > diff --git a/fs/read_write.c b/fs/read_write.c > index 177ccc3d405a..da521a221213 100644 > --- a/fs/read_write.c > +++ b/fs/read_write.c > @@ -1855,7 +1855,7 @@ static int vfs_dedupe_file_range_compare(struct inode *src, loff_t srcoff, > */ > int generic_remap_file_range_prep(struct file *file_in, loff_t pos_in, > struct file *file_out, loff_t pos_out, > - loff_t *len, unsigned int remap_flags) > + loff_t *len, unsigned int remap_flags, compare_range_t compare) Line wrapping... > { > struct inode *inode_in = file_inode(file_in); > struct inode *inode_out = file_inode(file_out); > @@ -1914,8 +1914,11 @@ int generic_remap_file_range_prep(struct file *file_in, loff_t pos_in, > */ > if (remap_flags & REMAP_FILE_DEDUP) { > bool is_same = false; > - > - ret = vfs_dedupe_file_range_compare(inode_in, pos_in, > + if (compare) > + ret = compare(inode_in, pos_in, > + inode_out, pos_out, *len, &is_same); > + else > + ret = vfs_dedupe_file_range_compare(inode_in, pos_in, > inode_out, pos_out, *len, &is_same); Make the callers pass in vfs_dedupe_file_range_compare instead of NULL, and avoid this if clause stuff. --D > if (ret) > return ret; > diff --git a/fs/xfs/xfs_reflink.c b/fs/xfs/xfs_reflink.c > index 680ae7662a78..8907c7aa3f19 100644 > --- a/fs/xfs/xfs_reflink.c > +++ b/fs/xfs/xfs_reflink.c > @@ -1350,7 +1350,7 @@ xfs_reflink_remap_prep( > goto out_unlock; > > ret = generic_remap_file_range_prep(file_in, pos_in, file_out, pos_out, > - len, remap_flags); > + len, remap_flags, NULL); > if (ret < 0 || *len == 0) > goto out_unlock; > > diff --git a/include/linux/dax.h b/include/linux/dax.h > index 0dd316a74a29..a11bc7b1f526 100644 > --- a/include/linux/dax.h > +++ b/include/linux/dax.h > @@ -157,6 +157,8 @@ vm_fault_t dax_finish_sync_fault(struct vm_fault *vmf, > int dax_delete_mapping_entry(struct address_space *mapping, pgoff_t index); > int dax_invalidate_mapping_entry_sync(struct address_space *mapping, > pgoff_t index); > +int dax_file_range_compare(struct inode *src, loff_t srcoff, struct inode *dest, > + loff_t destoff, loff_t len, bool *is_same, const struct iomap_ops *ops); > > #ifdef CONFIG_FS_DAX > int __dax_zero_page_range(struct block_device *bdev, > diff --git a/include/linux/fs.h b/include/linux/fs.h > index 8b42df09b04c..22fe4324b22e 100644 > --- a/include/linux/fs.h > +++ b/include/linux/fs.h > @@ -1880,10 +1880,12 @@ extern ssize_t vfs_readv(struct file *, const struct iovec __user *, > unsigned long, loff_t *, rwf_t); > extern ssize_t vfs_copy_file_range(struct file *, loff_t , struct file *, > loff_t, size_t, unsigned int); > +typedef int (compare_range_t)(struct inode *src, loff_t srcpos, struct inode *dest, > + loff_t destpos, loff_t len, bool *is_same); > extern int generic_remap_file_range_prep(struct file *file_in, loff_t pos_in, > struct file *file_out, loff_t pos_out, > loff_t *count, > - unsigned int remap_flags); > + unsigned int remap_flags, compare_range_t cmp); > extern loff_t do_clone_file_range(struct file *file_in, loff_t pos_in, > struct file *file_out, loff_t pos_out, > loff_t len, unsigned int remap_flags); > -- > 2.16.4 >
On 10:04 28/03, Darrick J. Wong wrote: > On Tue, Mar 26, 2019 at 02:02:57PM -0500, Goldwyn Rodrigues wrote: > > From: Goldwyn Rodrigues <rgoldwyn@suse.com> > > > > With dax we cannot deal with readpage() etc. So, we create a > > funciton callback to perform the file data comparison and pass > > it to generic_remap_file_range_prep() so it can use iomap-based > > functions. > > So it occurs to me -- is there an intrinsic requirement that all files > sharing blocks must be in DAX mode or not-DAX mode? Or in other words, > if I run cp --reflink a b, then it cannot be the case that IS_DAX(a) != > IS_DAX(b), right? > > Will there be calamitous consequences if dax and page cache both point > to the same piece of storage? I would imagine so... Yes, data corruptions! > > > This may not be the best way to solve this. Suggestions welcome. > > Agree. There's a fair amount of code duplication between the dax and > pagecache compare functions, considering that the loop structure for > both cases is: > > while (len) { > /* Figure out minimum comparison length */ > > /* Map source file range into memory */ > > /* Map dest file range into memory */ > > /* Compare memory */ > > /* Release dest file memory */ > > /* Release source file memory */ > > /* Update counters or break out */ > } > > The current vfs_dedupe_file_range_compare could use some improvements, > at least for filesystems where we actually support iomap. In > particular, if you try to dedupe into or out of a hole, it'll flood the > page cache with zero pages, which is pretty wasteful if we could've > found out that it's actually a hole. > > > Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com> > > --- > > fs/btrfs/ctree.h | 3 +++ > > fs/btrfs/dax.c | 7 +++++++ > > fs/btrfs/ioctl.c | 13 +++++++++++- > > fs/dax.c | 58 ++++++++++++++++++++++++++++++++++++++++++++++++++++ > > fs/ocfs2/file.c | 2 +- > > fs/read_write.c | 9 +++++--- > > fs/xfs/xfs_reflink.c | 2 +- > > include/linux/dax.h | 2 ++ > > include/linux/fs.h | 4 +++- > > 9 files changed, 93 insertions(+), 7 deletions(-) > > > > diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h > > index 0e5060933bde..750f9c70fabe 100644 > > --- a/fs/btrfs/ctree.h > > +++ b/fs/btrfs/ctree.h > > @@ -3803,6 +3803,9 @@ int btree_readahead_hook(struct extent_buffer *eb, int err); > > ssize_t btrfs_file_dax_read(struct kiocb *iocb, struct iov_iter *to); > > ssize_t btrfs_file_dax_write(struct kiocb *iocb, struct iov_iter *from); > > vm_fault_t btrfs_dax_fault(struct vm_fault *vmf); > > +int btrfs_dax_file_range_compare(struct inode *src, loff_t srcoff, > > + struct inode *dest, loff_t destoff, loff_t len, > > + bool *is_same); > > #else > > static inline ssize_t btrfs_file_dax_write(struct kiocb *iocb, struct iov_iter *from) > > { > > diff --git a/fs/btrfs/dax.c b/fs/btrfs/dax.c > > index 927f962d1e88..9488cae0f8b4 100644 > > --- a/fs/btrfs/dax.c > > +++ b/fs/btrfs/dax.c > > @@ -168,4 +168,11 @@ vm_fault_t btrfs_dax_fault(struct vm_fault *vmf) > > > > return ret; > > } > > + > > +int btrfs_dax_file_range_compare(struct inode *src, loff_t srcoff, > > + struct inode *dest, loff_t destoff, loff_t len, > > + bool *is_same) > > +{ > > + return dax_file_range_compare(src, srcoff, dest, destoff, len, is_same, &btrfs_iomap_ops); > > +} > > #endif /* CONFIG_FS_DAX */ > > diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c > > index e66426e7692d..2e5137b01561 100644 > > --- a/fs/btrfs/ioctl.c > > +++ b/fs/btrfs/ioctl.c > > @@ -3990,8 +3990,19 @@ static int btrfs_remap_file_range_prep(struct file *file_in, loff_t pos_in, > > if (ret < 0) > > goto out_unlock; > > > > +#ifdef CONFIG_FS_DAX > > + if (IS_DAX(file_inode(file_in)) && IS_DAX(file_inode(file_out))) > > + ret = generic_remap_file_range_prep(file_in, pos_in, file_out, > > + pos_out, len, remap_flags, > > + btrfs_dax_file_range_compare); > > + else > > + ret = generic_remap_file_range_prep(file_in, pos_in, file_out, > > + pos_out, len, remap_flags, NULL); > > +#else > > ret = generic_remap_file_range_prep(file_in, pos_in, file_out, pos_out, > > - len, remap_flags); > > + len, remap_flags, NULL); > > +#endif > > + > > if (ret < 0 || *len == 0) > > goto out_unlock; > > > > diff --git a/fs/dax.c b/fs/dax.c > > index 41061da42771..18998c5ee27a 100644 > > --- a/fs/dax.c > > +++ b/fs/dax.c > > @@ -1775,3 +1775,61 @@ vm_fault_t dax_finish_sync_fault(struct vm_fault *vmf, > > return dax_insert_pfn_mkwrite(vmf, pfn, order); > > } > > EXPORT_SYMBOL_GPL(dax_finish_sync_fault); > > + > > + > > +int dax_file_range_compare(struct inode *src, loff_t srcoff, struct inode *dest, > > + loff_t destoff, loff_t len, bool *is_same, const struct iomap_ops *ops) > > Comments for this function assume this is a vfs generic function, not a > dax specific thing... > > > +{ > > + void *saddr, *daddr; > > + struct iomap s_iomap = {0}; > > + struct iomap d_iomap = {0}; > > + loff_t dstart, sstart; > > + bool same = true; > > + loff_t cmp_len, l; > > + int id, ret = 0; > > + > > + id = dax_read_lock(); > > + while (len) { > > + ret = ops->iomap_begin(src, srcoff, len, 0, &s_iomap); > > + if (ret < 0) { > > + if (ops->iomap_end) > > + ops->iomap_end(src, srcoff, len, ret, 0, &s_iomap); > > + return ret; > > + } > > Shouldn't we be checking that the iomap actually points to written > storage? As opposed to hole/delalloc/unwritten? > > Bonus: not-written extents (hole/unwritten) could be optimized a bit, > though I don't know if it's worth it for something that's probably a > corner case. Yes, I think this needs to be optimized. However, from the VFS API end. As you mention above, it fills the pagecache unnecessarily. I feel file comparison is best handled by individual filesystems as opposed to the VFS. > > > + cmp_len = len; > > + if (cmp_len > s_iomap.offset + s_iomap.length - srcoff) > > + cmp_len = s_iomap.offset + s_iomap.length - srcoff; > > + > > + ret = ops->iomap_begin(dest, destoff, cmp_len, 0, &d_iomap); > > + if (ret < 0) { > > + if (ops->iomap_end) { > > + ops->iomap_end(src, srcoff, len, ret, 0, &s_iomap); > > + ops->iomap_end(dest, destoff, len, ret, 0, &d_iomap); > > + } > > + return ret; > > + } > > + if (cmp_len > d_iomap.offset + d_iomap.length - destoff) > > + cmp_len = d_iomap.offset + d_iomap.length - destoff; > > + > > If you wanted to make this a generic function, it would be kinda nice if > we could switch between grabbing page cache for non-DAX files and > dax_direct_access for DAX files. > > (Actually, no, that's kind of ugly too.) > > Perhaps iomap.c needs to grow a function to iterate ranges of two files > and call an actor function on both sets? And we can change the actor to > be the pagecache-grabbing one or the dax-access one depending on the DAX > mode. > Yes, that would work well. > Though I guess that leaves poor old ocfs2 in the dust since it doesn't > support iomap. I guess it wouldn't be too hard to adapt it to have an > iomap ops for reads only. > > > + > > + sstart = (get_start_sect(s_iomap.bdev) << 9) + s_iomap.addr + (srcoff - s_iomap.offset); > > + l = dax_direct_access(s_iomap.dax_dev, PHYS_PFN(sstart), PHYS_PFN(cmp_len), &saddr, NULL); > > + dstart = (get_start_sect(d_iomap.bdev) << 9) + d_iomap.addr + (destoff - d_iomap.offset); > > + l = dax_direct_access(d_iomap.dax_dev, PHYS_PFN(dstart), PHYS_PFN(cmp_len), &daddr, NULL); > > + same = !memcmp(saddr, daddr, cmp_len); > > + if (!same) > > + break; > > + len -= cmp_len; > > + srcoff += cmp_len; > > + destoff += cmp_len; > > + > > + if (ops->iomap_end) { > > + ret = ops->iomap_end(src, srcoff, len, 0, 0, &s_iomap); > > + ret = ops->iomap_end(dest, destoff, len, 0, 0, &d_iomap); > > + } > > + } > > + dax_read_unlock(id); > > + *is_same = same; > > + return ret; > > +} > > +EXPORT_SYMBOL_GPL(dax_file_range_compare); > > diff --git a/fs/ocfs2/file.c b/fs/ocfs2/file.c > > index d640c5f8a85d..6bf3e8fbb016 100644 > > --- a/fs/ocfs2/file.c > > +++ b/fs/ocfs2/file.c > > @@ -2558,7 +2558,7 @@ static loff_t ocfs2_remap_file_range(struct file *file_in, loff_t pos_in, > > goto out_unlock; > > > > ret = generic_remap_file_range_prep(file_in, pos_in, file_out, pos_out, > > - &len, remap_flags); > > + &len, remap_flags, NULL); > > if (ret < 0 || len == 0) > > goto out_unlock; > > > > diff --git a/fs/read_write.c b/fs/read_write.c > > index 177ccc3d405a..da521a221213 100644 > > --- a/fs/read_write.c > > +++ b/fs/read_write.c > > @@ -1855,7 +1855,7 @@ static int vfs_dedupe_file_range_compare(struct inode *src, loff_t srcoff, > > */ > > int generic_remap_file_range_prep(struct file *file_in, loff_t pos_in, > > struct file *file_out, loff_t pos_out, > > - loff_t *len, unsigned int remap_flags) > > + loff_t *len, unsigned int remap_flags, compare_range_t compare) > > Line wrapping... > > > { > > struct inode *inode_in = file_inode(file_in); > > struct inode *inode_out = file_inode(file_out); > > @@ -1914,8 +1914,11 @@ int generic_remap_file_range_prep(struct file *file_in, loff_t pos_in, > > */ > > if (remap_flags & REMAP_FILE_DEDUP) { > > bool is_same = false; > > - > > - ret = vfs_dedupe_file_range_compare(inode_in, pos_in, > > + if (compare) > > + ret = compare(inode_in, pos_in, > > + inode_out, pos_out, *len, &is_same); > > + else > > + ret = vfs_dedupe_file_range_compare(inode_in, pos_in, > > inode_out, pos_out, *len, &is_same); > > Make the callers pass in vfs_dedupe_file_range_compare instead of NULL, > and avoid this if clause stuff. Got it. Thanks. > > --D > > > if (ret) > > return ret; > > diff --git a/fs/xfs/xfs_reflink.c b/fs/xfs/xfs_reflink.c > > index 680ae7662a78..8907c7aa3f19 100644 > > --- a/fs/xfs/xfs_reflink.c > > +++ b/fs/xfs/xfs_reflink.c > > @@ -1350,7 +1350,7 @@ xfs_reflink_remap_prep( > > goto out_unlock; > > > > ret = generic_remap_file_range_prep(file_in, pos_in, file_out, pos_out, > > - len, remap_flags); > > + len, remap_flags, NULL); > > if (ret < 0 || *len == 0) > > goto out_unlock; > > > > diff --git a/include/linux/dax.h b/include/linux/dax.h > > index 0dd316a74a29..a11bc7b1f526 100644 > > --- a/include/linux/dax.h > > +++ b/include/linux/dax.h > > @@ -157,6 +157,8 @@ vm_fault_t dax_finish_sync_fault(struct vm_fault *vmf, > > int dax_delete_mapping_entry(struct address_space *mapping, pgoff_t index); > > int dax_invalidate_mapping_entry_sync(struct address_space *mapping, > > pgoff_t index); > > +int dax_file_range_compare(struct inode *src, loff_t srcoff, struct inode *dest, > > + loff_t destoff, loff_t len, bool *is_same, const struct iomap_ops *ops); > > > > #ifdef CONFIG_FS_DAX > > int __dax_zero_page_range(struct block_device *bdev, > > diff --git a/include/linux/fs.h b/include/linux/fs.h > > index 8b42df09b04c..22fe4324b22e 100644 > > --- a/include/linux/fs.h > > +++ b/include/linux/fs.h > > @@ -1880,10 +1880,12 @@ extern ssize_t vfs_readv(struct file *, const struct iovec __user *, > > unsigned long, loff_t *, rwf_t); > > extern ssize_t vfs_copy_file_range(struct file *, loff_t , struct file *, > > loff_t, size_t, unsigned int); > > +typedef int (compare_range_t)(struct inode *src, loff_t srcpos, struct inode *dest, > > + loff_t destpos, loff_t len, bool *is_same); > > extern int generic_remap_file_range_prep(struct file *file_in, loff_t pos_in, > > struct file *file_out, loff_t pos_out, > > loff_t *count, > > - unsigned int remap_flags); > > + unsigned int remap_flags, compare_range_t cmp); > > extern loff_t do_clone_file_range(struct file *file_in, loff_t pos_in, > > struct file *file_out, loff_t pos_out, > > loff_t len, unsigned int remap_flags); > > -- > > 2.16.4 > > >
diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h index 0e5060933bde..750f9c70fabe 100644 --- a/fs/btrfs/ctree.h +++ b/fs/btrfs/ctree.h @@ -3803,6 +3803,9 @@ int btree_readahead_hook(struct extent_buffer *eb, int err); ssize_t btrfs_file_dax_read(struct kiocb *iocb, struct iov_iter *to); ssize_t btrfs_file_dax_write(struct kiocb *iocb, struct iov_iter *from); vm_fault_t btrfs_dax_fault(struct vm_fault *vmf); +int btrfs_dax_file_range_compare(struct inode *src, loff_t srcoff, + struct inode *dest, loff_t destoff, loff_t len, + bool *is_same); #else static inline ssize_t btrfs_file_dax_write(struct kiocb *iocb, struct iov_iter *from) { diff --git a/fs/btrfs/dax.c b/fs/btrfs/dax.c index 927f962d1e88..9488cae0f8b4 100644 --- a/fs/btrfs/dax.c +++ b/fs/btrfs/dax.c @@ -168,4 +168,11 @@ vm_fault_t btrfs_dax_fault(struct vm_fault *vmf) return ret; } + +int btrfs_dax_file_range_compare(struct inode *src, loff_t srcoff, + struct inode *dest, loff_t destoff, loff_t len, + bool *is_same) +{ + return dax_file_range_compare(src, srcoff, dest, destoff, len, is_same, &btrfs_iomap_ops); +} #endif /* CONFIG_FS_DAX */ diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c index e66426e7692d..2e5137b01561 100644 --- a/fs/btrfs/ioctl.c +++ b/fs/btrfs/ioctl.c @@ -3990,8 +3990,19 @@ static int btrfs_remap_file_range_prep(struct file *file_in, loff_t pos_in, if (ret < 0) goto out_unlock; +#ifdef CONFIG_FS_DAX + if (IS_DAX(file_inode(file_in)) && IS_DAX(file_inode(file_out))) + ret = generic_remap_file_range_prep(file_in, pos_in, file_out, + pos_out, len, remap_flags, + btrfs_dax_file_range_compare); + else + ret = generic_remap_file_range_prep(file_in, pos_in, file_out, + pos_out, len, remap_flags, NULL); +#else ret = generic_remap_file_range_prep(file_in, pos_in, file_out, pos_out, - len, remap_flags); + len, remap_flags, NULL); +#endif + if (ret < 0 || *len == 0) goto out_unlock; diff --git a/fs/dax.c b/fs/dax.c index 41061da42771..18998c5ee27a 100644 --- a/fs/dax.c +++ b/fs/dax.c @@ -1775,3 +1775,61 @@ vm_fault_t dax_finish_sync_fault(struct vm_fault *vmf, return dax_insert_pfn_mkwrite(vmf, pfn, order); } EXPORT_SYMBOL_GPL(dax_finish_sync_fault); + + +int dax_file_range_compare(struct inode *src, loff_t srcoff, struct inode *dest, + loff_t destoff, loff_t len, bool *is_same, const struct iomap_ops *ops) +{ + void *saddr, *daddr; + struct iomap s_iomap = {0}; + struct iomap d_iomap = {0}; + loff_t dstart, sstart; + bool same = true; + loff_t cmp_len, l; + int id, ret = 0; + + id = dax_read_lock(); + while (len) { + ret = ops->iomap_begin(src, srcoff, len, 0, &s_iomap); + if (ret < 0) { + if (ops->iomap_end) + ops->iomap_end(src, srcoff, len, ret, 0, &s_iomap); + return ret; + } + cmp_len = len; + if (cmp_len > s_iomap.offset + s_iomap.length - srcoff) + cmp_len = s_iomap.offset + s_iomap.length - srcoff; + + ret = ops->iomap_begin(dest, destoff, cmp_len, 0, &d_iomap); + if (ret < 0) { + if (ops->iomap_end) { + ops->iomap_end(src, srcoff, len, ret, 0, &s_iomap); + ops->iomap_end(dest, destoff, len, ret, 0, &d_iomap); + } + return ret; + } + if (cmp_len > d_iomap.offset + d_iomap.length - destoff) + cmp_len = d_iomap.offset + d_iomap.length - destoff; + + + sstart = (get_start_sect(s_iomap.bdev) << 9) + s_iomap.addr + (srcoff - s_iomap.offset); + l = dax_direct_access(s_iomap.dax_dev, PHYS_PFN(sstart), PHYS_PFN(cmp_len), &saddr, NULL); + dstart = (get_start_sect(d_iomap.bdev) << 9) + d_iomap.addr + (destoff - d_iomap.offset); + l = dax_direct_access(d_iomap.dax_dev, PHYS_PFN(dstart), PHYS_PFN(cmp_len), &daddr, NULL); + same = !memcmp(saddr, daddr, cmp_len); + if (!same) + break; + len -= cmp_len; + srcoff += cmp_len; + destoff += cmp_len; + + if (ops->iomap_end) { + ret = ops->iomap_end(src, srcoff, len, 0, 0, &s_iomap); + ret = ops->iomap_end(dest, destoff, len, 0, 0, &d_iomap); + } + } + dax_read_unlock(id); + *is_same = same; + return ret; +} +EXPORT_SYMBOL_GPL(dax_file_range_compare); diff --git a/fs/ocfs2/file.c b/fs/ocfs2/file.c index d640c5f8a85d..6bf3e8fbb016 100644 --- a/fs/ocfs2/file.c +++ b/fs/ocfs2/file.c @@ -2558,7 +2558,7 @@ static loff_t ocfs2_remap_file_range(struct file *file_in, loff_t pos_in, goto out_unlock; ret = generic_remap_file_range_prep(file_in, pos_in, file_out, pos_out, - &len, remap_flags); + &len, remap_flags, NULL); if (ret < 0 || len == 0) goto out_unlock; diff --git a/fs/read_write.c b/fs/read_write.c index 177ccc3d405a..da521a221213 100644 --- a/fs/read_write.c +++ b/fs/read_write.c @@ -1855,7 +1855,7 @@ static int vfs_dedupe_file_range_compare(struct inode *src, loff_t srcoff, */ int generic_remap_file_range_prep(struct file *file_in, loff_t pos_in, struct file *file_out, loff_t pos_out, - loff_t *len, unsigned int remap_flags) + loff_t *len, unsigned int remap_flags, compare_range_t compare) { struct inode *inode_in = file_inode(file_in); struct inode *inode_out = file_inode(file_out); @@ -1914,8 +1914,11 @@ int generic_remap_file_range_prep(struct file *file_in, loff_t pos_in, */ if (remap_flags & REMAP_FILE_DEDUP) { bool is_same = false; - - ret = vfs_dedupe_file_range_compare(inode_in, pos_in, + if (compare) + ret = compare(inode_in, pos_in, + inode_out, pos_out, *len, &is_same); + else + ret = vfs_dedupe_file_range_compare(inode_in, pos_in, inode_out, pos_out, *len, &is_same); if (ret) return ret; diff --git a/fs/xfs/xfs_reflink.c b/fs/xfs/xfs_reflink.c index 680ae7662a78..8907c7aa3f19 100644 --- a/fs/xfs/xfs_reflink.c +++ b/fs/xfs/xfs_reflink.c @@ -1350,7 +1350,7 @@ xfs_reflink_remap_prep( goto out_unlock; ret = generic_remap_file_range_prep(file_in, pos_in, file_out, pos_out, - len, remap_flags); + len, remap_flags, NULL); if (ret < 0 || *len == 0) goto out_unlock; diff --git a/include/linux/dax.h b/include/linux/dax.h index 0dd316a74a29..a11bc7b1f526 100644 --- a/include/linux/dax.h +++ b/include/linux/dax.h @@ -157,6 +157,8 @@ vm_fault_t dax_finish_sync_fault(struct vm_fault *vmf, int dax_delete_mapping_entry(struct address_space *mapping, pgoff_t index); int dax_invalidate_mapping_entry_sync(struct address_space *mapping, pgoff_t index); +int dax_file_range_compare(struct inode *src, loff_t srcoff, struct inode *dest, + loff_t destoff, loff_t len, bool *is_same, const struct iomap_ops *ops); #ifdef CONFIG_FS_DAX int __dax_zero_page_range(struct block_device *bdev, diff --git a/include/linux/fs.h b/include/linux/fs.h index 8b42df09b04c..22fe4324b22e 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -1880,10 +1880,12 @@ extern ssize_t vfs_readv(struct file *, const struct iovec __user *, unsigned long, loff_t *, rwf_t); extern ssize_t vfs_copy_file_range(struct file *, loff_t , struct file *, loff_t, size_t, unsigned int); +typedef int (compare_range_t)(struct inode *src, loff_t srcpos, struct inode *dest, + loff_t destpos, loff_t len, bool *is_same); extern int generic_remap_file_range_prep(struct file *file_in, loff_t pos_in, struct file *file_out, loff_t pos_out, loff_t *count, - unsigned int remap_flags); + unsigned int remap_flags, compare_range_t cmp); extern loff_t do_clone_file_range(struct file *file_in, loff_t pos_in, struct file *file_out, loff_t pos_out, loff_t len, unsigned int remap_flags);