From c6f40468657d16e4010ef84bf32a761feb3469ea Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Mon, 29 Nov 2021 11:21:52 +0100 Subject: [PATCH] fsdax: decouple zeroing from the iomap buffered I/O code Unshare the DAX and iomap buffered I/O page zeroing code. This code previously did a IS_DAX check deep inside the iomap code, which in fact was the only DAX check in the code. Instead move these checks into the callers. Most callers already have DAX special casing anyway and XFS will need it for reflink support as well. Signed-off-by: Christoph Hellwig Reviewed-by: Dan Williams Reviewed-by: Darrick J. Wong Link: https://lore.kernel.org/r/20211129102203.2243509-19-hch@lst.de Signed-off-by: Dan Williams --- fs/dax.c | 77 +++++++++++++++++++++++++++++++++++++++++--------- fs/ext2/inode.c | 7 +++-- fs/ext4/inode.c | 5 ++-- fs/iomap/buffered-io.c | 35 ++++++++--------------- fs/xfs/xfs_iomap.c | 7 ++++- include/linux/dax.h | 7 ++++- 6 files changed, 94 insertions(+), 44 deletions(-) diff --git a/fs/dax.c b/fs/dax.c index d5db129..43d58b4 100644 --- a/fs/dax.c +++ b/fs/dax.c @@ -1135,24 +1135,73 @@ static int dax_memzero(struct dax_device *dax_dev, pgoff_t pgoff, return ret; } -s64 dax_iomap_zero(loff_t pos, u64 length, struct iomap *iomap) +static s64 dax_zero_iter(struct iomap_iter *iter, bool *did_zero) { - pgoff_t pgoff = dax_iomap_pgoff(iomap, pos); - long rc, id; - unsigned offset = offset_in_page(pos); - unsigned size = min_t(u64, PAGE_SIZE - offset, length); + const struct iomap *iomap = &iter->iomap; + const struct iomap *srcmap = iomap_iter_srcmap(iter); + loff_t pos = iter->pos; + u64 length = iomap_length(iter); + s64 written = 0; + + /* already zeroed? we're done. */ + if (srcmap->type == IOMAP_HOLE || srcmap->type == IOMAP_UNWRITTEN) + return length; + + do { + unsigned offset = offset_in_page(pos); + unsigned size = min_t(u64, PAGE_SIZE - offset, length); + pgoff_t pgoff = dax_iomap_pgoff(iomap, pos); + long rc; + int id; - id = dax_read_lock(); - if (IS_ALIGNED(pos, PAGE_SIZE) && size == PAGE_SIZE) - rc = dax_zero_page_range(iomap->dax_dev, pgoff, 1); - else - rc = dax_memzero(iomap->dax_dev, pgoff, offset, size); - dax_read_unlock(id); + id = dax_read_lock(); + if (IS_ALIGNED(pos, PAGE_SIZE) && size == PAGE_SIZE) + rc = dax_zero_page_range(iomap->dax_dev, pgoff, 1); + else + rc = dax_memzero(iomap->dax_dev, pgoff, offset, size); + dax_read_unlock(id); - if (rc < 0) - return rc; - return size; + if (rc < 0) + return rc; + pos += size; + length -= size; + written += size; + if (did_zero) + *did_zero = true; + } while (length > 0); + + return written; +} + +int dax_zero_range(struct inode *inode, loff_t pos, loff_t len, bool *did_zero, + const struct iomap_ops *ops) +{ + struct iomap_iter iter = { + .inode = inode, + .pos = pos, + .len = len, + .flags = IOMAP_ZERO, + }; + int ret; + + while ((ret = iomap_iter(&iter, ops)) > 0) + iter.processed = dax_zero_iter(&iter, did_zero); + return ret; +} +EXPORT_SYMBOL_GPL(dax_zero_range); + +int dax_truncate_page(struct inode *inode, loff_t pos, bool *did_zero, + const struct iomap_ops *ops) +{ + unsigned int blocksize = i_blocksize(inode); + unsigned int off = pos & (blocksize - 1); + + /* Block boundary? Nothing to do */ + if (!off) + return 0; + return dax_zero_range(inode, pos, blocksize - off, did_zero, ops); } +EXPORT_SYMBOL_GPL(dax_truncate_page); static loff_t dax_iomap_iter(const struct iomap_iter *iomi, struct iov_iter *iter) diff --git a/fs/ext2/inode.c b/fs/ext2/inode.c index 333fa62..01d6961 100644 --- a/fs/ext2/inode.c +++ b/fs/ext2/inode.c @@ -36,6 +36,7 @@ #include #include #include +#include #include "ext2.h" #include "acl.h" #include "xattr.h" @@ -1297,9 +1298,9 @@ static int ext2_setsize(struct inode *inode, loff_t newsize) inode_dio_wait(inode); if (IS_DAX(inode)) { - error = iomap_zero_range(inode, newsize, - PAGE_ALIGN(newsize) - newsize, NULL, - &ext2_iomap_ops); + error = dax_zero_range(inode, newsize, + PAGE_ALIGN(newsize) - newsize, NULL, + &ext2_iomap_ops); } else if (test_opt(inode->i_sb, NOBH)) error = nobh_truncate_page(inode->i_mapping, newsize, ext2_get_block); diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index bfd3545..d316a20 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -41,6 +41,7 @@ #include #include #include +#include #include "ext4_jbd2.h" #include "xattr.h" @@ -3780,8 +3781,8 @@ static int ext4_block_zero_page_range(handle_t *handle, length = max; if (IS_DAX(inode)) { - return iomap_zero_range(inode, from, length, NULL, - &ext4_iomap_ops); + return dax_zero_range(inode, from, length, NULL, + &ext4_iomap_ops); } return __ext4_block_zero_page_range(handle, mapping, from, length); } diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c index 1753c26..b151125 100644 --- a/fs/iomap/buffered-io.c +++ b/fs/iomap/buffered-io.c @@ -870,26 +870,8 @@ iomap_file_unshare(struct inode *inode, loff_t pos, loff_t len, } EXPORT_SYMBOL_GPL(iomap_file_unshare); -static s64 __iomap_zero_iter(struct iomap_iter *iter, loff_t pos, u64 length) -{ - struct page *page; - int status; - unsigned offset = offset_in_page(pos); - unsigned bytes = min_t(u64, PAGE_SIZE - offset, length); - - status = iomap_write_begin(iter, pos, bytes, &page); - if (status) - return status; - - zero_user(page, offset, bytes); - mark_page_accessed(page); - - return iomap_write_end(iter, pos, bytes, bytes, page); -} - static loff_t iomap_zero_iter(struct iomap_iter *iter, bool *did_zero) { - struct iomap *iomap = &iter->iomap; const struct iomap *srcmap = iomap_iter_srcmap(iter); loff_t pos = iter->pos; loff_t length = iomap_length(iter); @@ -900,12 +882,19 @@ static loff_t iomap_zero_iter(struct iomap_iter *iter, bool *did_zero) return length; do { - s64 bytes; + unsigned offset = offset_in_page(pos); + size_t bytes = min_t(u64, PAGE_SIZE - offset, length); + struct page *page; + int status; - if (IS_DAX(iter->inode)) - bytes = dax_iomap_zero(pos, length, iomap); - else - bytes = __iomap_zero_iter(iter, pos, length); + status = iomap_write_begin(iter, pos, bytes, &page); + if (status) + return status; + + zero_user(page, offset, bytes); + mark_page_accessed(page); + + bytes = iomap_write_end(iter, pos, bytes, bytes, page); if (bytes < 0) return bytes; diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c index d6d71ae..6a0c3b3 100644 --- a/fs/xfs/xfs_iomap.c +++ b/fs/xfs/xfs_iomap.c @@ -28,7 +28,6 @@ #include "xfs_dquot.h" #include "xfs_reflink.h" - #define XFS_ALLOC_ALIGN(mp, off) \ (((off) >> mp->m_allocsize_log) << mp->m_allocsize_log) @@ -1321,6 +1320,9 @@ xfs_zero_range( { struct inode *inode = VFS_I(ip); + if (IS_DAX(inode)) + return dax_zero_range(inode, pos, len, did_zero, + &xfs_buffered_write_iomap_ops); return iomap_zero_range(inode, pos, len, did_zero, &xfs_buffered_write_iomap_ops); } @@ -1333,6 +1335,9 @@ xfs_truncate_page( { struct inode *inode = VFS_I(ip); + if (IS_DAX(inode)) + return dax_truncate_page(inode, pos, did_zero, + &xfs_buffered_write_iomap_ops); return iomap_truncate_page(inode, pos, did_zero, &xfs_buffered_write_iomap_ops); } diff --git a/include/linux/dax.h b/include/linux/dax.h index 324363b7..b790367 100644 --- a/include/linux/dax.h +++ b/include/linux/dax.h @@ -14,6 +14,7 @@ typedef unsigned long dax_entry_t; struct dax_device; struct gendisk; struct iomap_ops; +struct iomap_iter; struct iomap; struct dax_operations { @@ -170,6 +171,11 @@ static inline void dax_unlock_page(struct page *page, dax_entry_t cookie) } #endif +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, + const struct iomap_ops *ops); + #if IS_ENABLED(CONFIG_DAX) int dax_read_lock(void); void dax_read_unlock(int id); @@ -204,7 +210,6 @@ 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); -s64 dax_iomap_zero(loff_t pos, u64 length, struct iomap *iomap); static inline bool dax_mapping(struct address_space *mapping) { return mapping->host && IS_DAX(mapping->host); -- 2.7.4