* [PATCH 1/2] iomap: remove over-strict inline data boundary check
2026-04-23 21:32 [PATCH 0/2] iomap/ntfs: remove over-strict inline data check and optimize ntfs Namjae Jeon
@ 2026-04-23 21:32 ` Namjae Jeon
2026-04-23 21:32 ` [PATCH 2/2] ntfs: use direct pointer for inline data to avoid redundant allocation Namjae Jeon
1 sibling, 0 replies; 3+ messages in thread
From: Namjae Jeon @ 2026-04-23 21:32 UTC (permalink / raw)
To: brauner, djwong, hyc.lee; +Cc: willy, xiang, hch, linux-fsdevel, Namjae Jeon
The current iomap_inline_data_valid() check ensures that inline data
does not cross a PAGE_SIZE boundary. However, this is an unnecessarily
strict constraint. If a filesystem provides a valid iomap::inline_data
pointer and iomap::length, we should trust that the caller has mapped
sufficient memory for the range, even if it spans across page boundaries.
Removing this check allows filesystems to point directly to their
internal data structures without forced page-alignment or additional
redundant allocations. This remove iomap_inline_data_valid() and
its callers in buffered and direct I/O paths.
Suggested-by: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
---
fs/iomap/buffered-io.c | 1 -
fs/iomap/direct-io.c | 3 ---
include/linux/iomap.h | 10 ----------
3 files changed, 14 deletions(-)
diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c
index d7b648421a70..c4c5bddcbe3a 100644
--- a/fs/iomap/buffered-io.c
+++ b/fs/iomap/buffered-io.c
@@ -1058,7 +1058,6 @@ static bool iomap_write_end_inline(const struct iomap_iter *iter,
void *addr;
WARN_ON_ONCE(!folio_test_uptodate(folio));
- BUG_ON(!iomap_inline_data_valid(iomap));
if (WARN_ON_ONCE(!iomap->inline_data))
return false;
diff --git a/fs/iomap/direct-io.c b/fs/iomap/direct-io.c
index b0a6549b3848..a4459c5abb07 100644
--- a/fs/iomap/direct-io.c
+++ b/fs/iomap/direct-io.c
@@ -603,9 +603,6 @@ static int iomap_dio_inline_iter(struct iomap_iter *iomi, struct iomap_dio *dio)
if (WARN_ON_ONCE(!inline_data))
return -EIO;
- if (WARN_ON_ONCE(!iomap_inline_data_valid(iomap)))
- return -EIO;
-
if (dio->flags & IOMAP_DIO_WRITE) {
loff_t size = iomi->inode->i_size;
diff --git a/include/linux/iomap.h b/include/linux/iomap.h
index 2c5685adf3a9..52bfd6783417 100644
--- a/include/linux/iomap.h
+++ b/include/linux/iomap.h
@@ -142,16 +142,6 @@ static inline void *iomap_inline_data(const struct iomap *iomap, loff_t pos)
return iomap->inline_data + pos - iomap->offset;
}
-/*
- * Check if the mapping's length is within the valid range for inline data.
- * This is used to guard against accessing data beyond the page inline_data
- * points at.
- */
-static inline bool iomap_inline_data_valid(const struct iomap *iomap)
-{
- return iomap->length <= PAGE_SIZE - offset_in_page(iomap->inline_data);
-}
-
/*
* When get_folio succeeds, put_folio will always be called to do any
* cleanup work necessary. put_folio is responsible for unlocking and putting
--
2.25.1
^ permalink raw reply related [flat|nested] 3+ messages in thread* [PATCH 2/2] ntfs: use direct pointer for inline data to avoid redundant allocation
2026-04-23 21:32 [PATCH 0/2] iomap/ntfs: remove over-strict inline data check and optimize ntfs Namjae Jeon
2026-04-23 21:32 ` [PATCH 1/2] iomap: remove over-strict inline data boundary check Namjae Jeon
@ 2026-04-23 21:32 ` Namjae Jeon
1 sibling, 0 replies; 3+ messages in thread
From: Namjae Jeon @ 2026-04-23 21:32 UTC (permalink / raw)
To: brauner, djwong, hyc.lee; +Cc: willy, xiang, hch, linux-fsdevel, Namjae Jeon
Previously, NTFS used page allocation for IOMAP_INLINE to ensure that
the inline_data pointer was page-aligned, avoiding strict boundary checks
in the iomap core. Since the previous patch has removed the over-strict
PAGE_SIZE boundary check in iomap, NTFS can now safely point
iomap::inline_data directly to the MFT record.
This change eliminates redundant memory allocations and memcpy operations
in both read and write paths. It also simplifies the iomap_ops by removing
the need for a iomap_end callback that was previously used to free
the temporary page.
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
---
fs/ntfs/iomap.c | 76 ++++---------------------------------------------
1 file changed, 6 insertions(+), 70 deletions(-)
diff --git a/fs/ntfs/iomap.c b/fs/ntfs/iomap.c
index 7a170df39e72..ca8e221e5b7b 100644
--- a/fs/ntfs/iomap.c
+++ b/fs/ntfs/iomap.c
@@ -89,7 +89,6 @@ static int ntfs_read_iomap_begin_resident(struct inode *inode, loff_t offset, lo
u32 attr_len;
int err = 0;
char *kattr;
- struct page *ipage;
if (NInoAttr(ni))
base_ni = ni->ext.base_ntfs_ino;
@@ -130,18 +129,10 @@ static int ntfs_read_iomap_begin_resident(struct inode *inode, loff_t offset, lo
kattr = (u8 *)ctx->attr + le16_to_cpu(ctx->attr->data.resident.value_offset);
- ipage = alloc_page(GFP_NOFS | __GFP_ZERO);
- if (!ipage) {
- err = -ENOMEM;
- goto out;
- }
-
- memcpy(page_address(ipage), kattr, attr_len);
iomap->type = IOMAP_INLINE;
- iomap->inline_data = page_address(ipage);
+ iomap->inline_data = kattr;
iomap->offset = 0;
iomap->length = attr_len;
- iomap->private = ipage;
out:
if (ctx)
@@ -286,21 +277,8 @@ static int ntfs_read_iomap_begin(struct inode *inode, loff_t offset, loff_t leng
srcmap, true);
}
-static int ntfs_read_iomap_end(struct inode *inode, loff_t pos, loff_t length,
- ssize_t written, unsigned int flags, struct iomap *iomap)
-{
- if (iomap->type == IOMAP_INLINE) {
- struct page *ipage = iomap->private;
-
- put_page(ipage);
- }
-
- return written;
-}
-
const struct iomap_ops ntfs_read_iomap_ops = {
.iomap_begin = ntfs_read_iomap_begin,
- .iomap_end = ntfs_read_iomap_end,
};
/*
@@ -358,7 +336,6 @@ static const struct iomap_ops ntfs_zero_read_iomap_ops = {
const struct iomap_ops ntfs_seek_iomap_ops = {
.iomap_begin = ntfs_seek_iomap_begin,
- .iomap_end = ntfs_read_iomap_end,
};
int ntfs_dio_zero_range(struct inode *inode, loff_t offset, loff_t length)
@@ -659,7 +636,6 @@ static int ntfs_write_iomap_begin_resident(struct inode *inode, loff_t offset,
u32 attr_len;
int err = 0;
char *kattr;
- struct page *ipage;
ctx = ntfs_attr_get_search_ctx(ni, NULL);
if (!ctx) {
@@ -680,24 +656,18 @@ static int ntfs_write_iomap_begin_resident(struct inode *inode, loff_t offset,
attr_len = le32_to_cpu(a->data.resident.value_length);
kattr = (u8 *)a + le16_to_cpu(a->data.resident.value_offset);
- ipage = alloc_page(GFP_NOFS | __GFP_ZERO);
- if (!ipage) {
- err = -ENOMEM;
- goto out;
- }
-
- memcpy(page_address(ipage), kattr, attr_len);
iomap->type = IOMAP_INLINE;
- iomap->inline_data = page_address(ipage);
+ iomap->inline_data = kattr;
iomap->offset = 0;
- /* iomap requires there is only one INLINE_DATA extent */
iomap->length = attr_len;
- iomap->private = ipage;
out:
if (ctx)
ntfs_attr_put_search_ctx(ctx);
- mutex_unlock(&ni->mrec_lock);
+
+ if (err)
+ mutex_unlock(&ni->mrec_lock);
+
return err;
}
@@ -778,43 +748,9 @@ static int ntfs_write_iomap_end_resident(struct inode *inode, loff_t pos,
unsigned int flags, struct iomap *iomap)
{
struct ntfs_inode *ni = NTFS_I(inode);
- struct ntfs_attr_search_ctx *ctx;
- u32 attr_len;
- int err;
- char *kattr;
- struct page *ipage = iomap->private;
-
- mutex_lock(&ni->mrec_lock);
- ctx = ntfs_attr_get_search_ctx(ni, NULL);
- if (!ctx) {
- written = -ENOMEM;
- mutex_unlock(&ni->mrec_lock);
- return written;
- }
-
- err = ntfs_attr_lookup(ni->type, ni->name, ni->name_len,
- CASE_SENSITIVE, 0, NULL, 0, ctx);
- if (err) {
- if (err == -ENOENT)
- err = -EIO;
- written = err;
- goto err_out;
- }
- /* The total length of the attribute value. */
- attr_len = le32_to_cpu(ctx->attr->data.resident.value_length);
- if (pos >= attr_len || pos + written > attr_len)
- goto err_out;
-
- kattr = (u8 *)ctx->attr + le16_to_cpu(ctx->attr->data.resident.value_offset);
- memcpy(kattr + pos, iomap_inline_data(iomap, pos), written);
- mark_mft_record_dirty(ctx->ntfs_ino);
-err_out:
- ntfs_attr_put_search_ctx(ctx);
- put_page(ipage);
mutex_unlock(&ni->mrec_lock);
return written;
-
}
static int ntfs_write_iomap_end(struct inode *inode, loff_t pos, loff_t length,
--
2.25.1
^ permalink raw reply related [flat|nested] 3+ messages in thread