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ntfs: use direct pointer for inline data to avoid redundant allocation

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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.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
This commit is contained in:
Namjae Jeon
2026-06-09 21:16:50 +09:00
parent fcf5bf0e85
commit 5aec1efb11
1 changed files with 7 additions and 70 deletions
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77
fs/ntfs/iomap.c
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@@ -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 +748,10 @@ 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;
goto err_out;
}
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:
if (ctx)
ntfs_attr_put_search_ctx(ctx);
put_page(ipage);
mark_mft_record_dirty(ni);
mutex_unlock(&ni->mrec_lock);
return written;
}
static int ntfs_write_iomap_end(struct inode *inode, loff_t pos, loff_t length,