6.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Shiyang Ruan <ruansy.fnst@xxxxxxxxxxx> [ Upstream commit d984648e428bf88cbd94ebe346c73632cb92fffb ] Implement unshare in fsdax mode: copy data from srcmap to iomap. Link: https://lkml.kernel.org/r/1669908753-169-1-git-send-email-ruansy.fnst@xxxxxxxxxxx Signed-off-by: Shiyang Ruan <ruansy.fnst@xxxxxxxxxxx> Reviewed-by: Darrick J. Wong <djwong@xxxxxxxxxx> Cc: Alistair Popple <apopple@xxxxxxxxxx> Cc: Dan Williams <dan.j.williams@xxxxxxxxx> Cc: Dave Chinner <david@xxxxxxxxxxxxx> Cc: Jason Gunthorpe <jgg@xxxxxxxxxx> Cc: John Hubbard <jhubbard@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> Stable-dep-of: a311a08a4237 ("iomap: constrain the file range passed to iomap_file_unshare") Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- fs/dax.c | 52 ++++++++++++++++++++++++++++++++++++++++++++ fs/xfs/xfs_reflink.c | 8 +++++-- include/linux/dax.h | 2 ++ 3 files changed, 60 insertions(+), 2 deletions(-) diff --git a/fs/dax.c b/fs/dax.c index 1c6867810cbd6..626745bc1ad86 100644 --- a/fs/dax.c +++ b/fs/dax.c @@ -1221,6 +1221,58 @@ static vm_fault_t dax_pmd_load_hole(struct xa_state *xas, struct vm_fault *vmf, } #endif /* CONFIG_FS_DAX_PMD */ +static s64 dax_unshare_iter(struct iomap_iter *iter) +{ + struct iomap *iomap = &iter->iomap; + const struct iomap *srcmap = iomap_iter_srcmap(iter); + loff_t pos = iter->pos; + loff_t length = iomap_length(iter); + int id = 0; + s64 ret = 0; + void *daddr = NULL, *saddr = NULL; + + /* don't bother with blocks that are not shared to start with */ + if (!(iomap->flags & IOMAP_F_SHARED)) + return length; + /* don't bother with holes or unwritten extents */ + if (srcmap->type == IOMAP_HOLE || srcmap->type == IOMAP_UNWRITTEN) + return length; + + id = dax_read_lock(); + ret = dax_iomap_direct_access(iomap, pos, length, &daddr, NULL); + if (ret < 0) + goto out_unlock; + + ret = dax_iomap_direct_access(srcmap, pos, length, &saddr, NULL); + if (ret < 0) + goto out_unlock; + + ret = copy_mc_to_kernel(daddr, saddr, length); + if (ret) + ret = -EIO; + +out_unlock: + dax_read_unlock(id); + return ret; +} + +int dax_file_unshare(struct inode *inode, loff_t pos, loff_t len, + const struct iomap_ops *ops) +{ + struct iomap_iter iter = { + .inode = inode, + .pos = pos, + .len = len, + .flags = IOMAP_WRITE | IOMAP_UNSHARE | IOMAP_DAX, + }; + int ret; + + while ((ret = iomap_iter(&iter, ops)) > 0) + iter.processed = dax_unshare_iter(&iter); + return ret; +} +EXPORT_SYMBOL_GPL(dax_file_unshare); + static int dax_memzero(struct iomap_iter *iter, loff_t pos, size_t size) { const struct iomap *iomap = &iter->iomap; diff --git a/fs/xfs/xfs_reflink.c b/fs/xfs/xfs_reflink.c index 93bdd25680bc9..fe46bce8cae63 100644 --- a/fs/xfs/xfs_reflink.c +++ b/fs/xfs/xfs_reflink.c @@ -1693,8 +1693,12 @@ xfs_reflink_unshare( inode_dio_wait(inode); - error = iomap_file_unshare(inode, offset, len, - &xfs_buffered_write_iomap_ops); + if (IS_DAX(inode)) + error = dax_file_unshare(inode, offset, len, + &xfs_dax_write_iomap_ops); + else + error = iomap_file_unshare(inode, offset, len, + &xfs_buffered_write_iomap_ops); if (error) goto out; diff --git a/include/linux/dax.h b/include/linux/dax.h index ba985333e26bf..2b5ecb5910591 100644 --- a/include/linux/dax.h +++ b/include/linux/dax.h @@ -205,6 +205,8 @@ static inline void dax_unlock_mapping_entry(struct address_space *mapping, } #endif +int dax_file_unshare(struct inode *inode, loff_t pos, loff_t len, + const struct iomap_ops *ops); int dax_zero_range(struct inode *inode, loff_t pos, loff_t len, bool *did_zero, const struct iomap_ops *ops); int dax_truncate_page(struct inode *inode, loff_t pos, bool *did_zero, -- 2.43.0
