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Message-ID: <20251114095516.207555-3-lihongbo22@huawei.com>
Date: Fri, 14 Nov 2025 09:55:09 +0000
From: Hongbo Li <lihongbo22@...wei.com>
To: <hsiangkao@...ux.alibaba.com>, <chao@...nel.org>, <brauner@...nel.org>,
<djwong@...nel.org>, <amir73il@...il.com>, <joannelkoong@...il.com>
CC: <linux-fsdevel@...r.kernel.org>, <linux-erofs@...ts.ozlabs.org>,
<linux-kernel@...r.kernel.org>
Subject: [PATCH v8 2/9] erofs: hold read context in iomap_iter if needed
Uncoming page cache sharing needs pass read context to iomap_iter,
here we unify the way of passing the read context in EROFS. Moreover,
bmap and fiemap don't need to map the inline data.
Note that we keep `struct page *` in `struct erofs_iomap_iter_ctx` as
well to avoid bogus kmap_to_page usage.
Signed-off-by: Hongbo Li <lihongbo22@...wei.com>
---
fs/erofs/data.c | 79 ++++++++++++++++++++++++++++++++++++-------------
1 file changed, 59 insertions(+), 20 deletions(-)
diff --git a/fs/erofs/data.c b/fs/erofs/data.c
index bb13c4cb8455..bd3d85c61341 100644
--- a/fs/erofs/data.c
+++ b/fs/erofs/data.c
@@ -266,14 +266,23 @@ void erofs_onlinefolio_end(struct folio *folio, int err, bool dirty)
folio_end_read(folio, !(v & BIT(EROFS_ONLINEFOLIO_EIO)));
}
+struct erofs_iomap_iter_ctx {
+ struct page *page;
+ void *base;
+};
+
static int erofs_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
unsigned int flags, struct iomap *iomap, struct iomap *srcmap)
{
int ret;
+ struct erofs_iomap_iter_ctx *ctx;
struct super_block *sb = inode->i_sb;
struct erofs_map_blocks map;
struct erofs_map_dev mdev;
+ struct iomap_iter *iter;
+ iter = container_of(iomap, struct iomap_iter, iomap);
+ ctx = iter->private;
map.m_la = offset;
map.m_llen = length;
ret = erofs_map_blocks(inode, &map);
@@ -283,7 +292,8 @@ static int erofs_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
iomap->offset = map.m_la;
iomap->length = map.m_llen;
iomap->flags = 0;
- iomap->private = NULL;
+ if (ctx)
+ ctx->base = NULL;
iomap->addr = IOMAP_NULL_ADDR;
if (!(map.m_flags & EROFS_MAP_MAPPED)) {
iomap->type = IOMAP_HOLE;
@@ -309,16 +319,20 @@ static int erofs_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
}
if (map.m_flags & EROFS_MAP_META) {
- void *ptr;
- struct erofs_buf buf = __EROFS_BUF_INITIALIZER;
-
iomap->type = IOMAP_INLINE;
- ptr = erofs_read_metabuf(&buf, sb, map.m_pa,
- erofs_inode_in_metabox(inode));
- if (IS_ERR(ptr))
- return PTR_ERR(ptr);
- iomap->inline_data = ptr;
- iomap->private = buf.base;
+ /* read context should read the inlined data */
+ if (ctx) {
+ void *ptr;
+ struct erofs_buf buf = __EROFS_BUF_INITIALIZER;
+
+ ptr = erofs_read_metabuf(&buf, sb, map.m_pa,
+ erofs_inode_in_metabox(inode));
+ if (IS_ERR(ptr))
+ return PTR_ERR(ptr);
+ iomap->inline_data = ptr;
+ ctx->page = buf.page;
+ ctx->base = buf.base;
+ }
} else {
iomap->type = IOMAP_MAPPED;
}
@@ -328,18 +342,19 @@ static int erofs_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
static int erofs_iomap_end(struct inode *inode, loff_t pos, loff_t length,
ssize_t written, unsigned int flags, struct iomap *iomap)
{
- void *ptr = iomap->private;
+ struct erofs_iomap_iter_ctx *ctx;
+ struct iomap_iter *iter;
- if (ptr) {
+ iter = container_of(iomap, struct iomap_iter, iomap);
+ ctx = iter->private;
+ if (ctx && ctx->base) {
struct erofs_buf buf = {
- .page = kmap_to_page(ptr),
- .base = ptr,
+ .page = ctx->page,
+ .base = ctx->base,
};
DBG_BUGON(iomap->type != IOMAP_INLINE);
erofs_put_metabuf(&buf);
- } else {
- DBG_BUGON(iomap->type == IOMAP_INLINE);
}
return written;
}
@@ -369,18 +384,36 @@ int erofs_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
*/
static int erofs_read_folio(struct file *file, struct folio *folio)
{
+ struct iomap_read_folio_ctx read_ctx = {
+ .ops = &iomap_bio_read_ops,
+ .cur_folio = folio,
+ };
+ struct erofs_iomap_iter_ctx iter_ctx = {
+ .page = NULL,
+ .base = NULL,
+ };
+
trace_erofs_read_folio(folio, true);
- iomap_bio_read_folio(folio, &erofs_iomap_ops);
+ iomap_read_folio(&erofs_iomap_ops, &read_ctx, &iter_ctx);
return 0;
}
static void erofs_readahead(struct readahead_control *rac)
{
+ struct iomap_read_folio_ctx read_ctx = {
+ .ops = &iomap_bio_read_ops,
+ .rac = rac,
+ };
+ struct erofs_iomap_iter_ctx iter_ctx = {
+ .page = NULL,
+ .base = NULL,
+ };
+
trace_erofs_readahead(rac->mapping->host, readahead_index(rac),
readahead_count(rac), true);
- iomap_bio_readahead(rac, &erofs_iomap_ops);
+ iomap_readahead(&erofs_iomap_ops, &read_ctx, &iter_ctx);
}
static sector_t erofs_bmap(struct address_space *mapping, sector_t block)
@@ -400,9 +433,15 @@ static ssize_t erofs_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
if (IS_DAX(inode))
return dax_iomap_rw(iocb, to, &erofs_iomap_ops);
#endif
- if ((iocb->ki_flags & IOCB_DIRECT) && inode->i_sb->s_bdev)
+ if ((iocb->ki_flags & IOCB_DIRECT) && inode->i_sb->s_bdev) {
+ struct erofs_iomap_iter_ctx iter_ctx = {
+ .page = NULL,
+ .base = NULL,
+ };
+
return iomap_dio_rw(iocb, to, &erofs_iomap_ops,
- NULL, 0, NULL, 0);
+ NULL, 0, &iter_ctx, 0);
+ }
return filemap_read(iocb, to, 0);
}
--
2.22.0
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