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erofs: hold read context in iomap_iter if needed

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Introduce `struct erofs_iomap_iter_ctx` to hold both `struct page *`
and `void *base`, avoiding bogus use of `kmap_to_page()` in
`erofs_iomap_end()`.

With this change, fiemap and bmap no longer need to read inline data.

Additionally, the upcoming page cache sharing mechanism requires
passing the backing inode pointer to `erofs_iomap_{begin,end}()`, as
I/O accesses must apply to backing inodes rather than anon inodes.

Signed-off-by: Hongbo Li <lihongbo22@huawei.com>
Link: https://patch.msgid.link/20260109102856.598531-3-lihongbo22@huawei.com
Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
This commit is contained in:
Hongbo Li 2026-01-09 10:28:48 +00:00 committed by Christian Brauner
parent 8806f27924
commit 8d407bb321
No known key found for this signature in database
GPG Key ID: 91C61BC06578DCA2
1 changed files with 46 additions and 21 deletions
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67
fs/erofs/data.c
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@ -266,13 +266,20 @@ 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 iomap_iter *iter = container_of(iomap, struct iomap_iter, iomap);
struct erofs_iomap_iter_ctx *ctx = iter->private;
struct super_block *sb = inode->i_sb;
struct erofs_map_blocks map;
struct erofs_map_dev mdev;
int ret;
map.m_la = offset;
map.m_llen = length;
@ -283,7 +290,6 @@ 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;
iomap->addr = IOMAP_NULL_ADDR;
if (!(map.m_flags & EROFS_MAP_MAPPED)) {
iomap->type = IOMAP_HOLE;
@ -309,16 +315,20 @@ 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) {
struct erofs_buf buf = __EROFS_BUF_INITIALIZER;
void *ptr;
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 +338,18 @@ 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 iomap_iter *iter = container_of(iomap, struct iomap_iter, iomap);
struct erofs_iomap_iter_ctx *ctx = iter->private;
if (ptr) {
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);
ctx->base = NULL;
}
return written;
}
@ -369,18 +379,30 @@ 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 = {};
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 = {};
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 +422,12 @@ 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 = {};
return iomap_dio_rw(iocb, to, &erofs_iomap_ops,
NULL, 0, NULL, 0);
NULL, 0, &iter_ctx, 0);
}
return filemap_read(iocb, to, 0);
}