* [PATCH v9 00/10] erofs: inode page cache share feature
@ 2025-11-17 13:25 Hongbo Li
2025-11-17 13:25 ` [PATCH v9 01/10] iomap: stash iomap read ctx in the private field of iomap_iter Hongbo Li
` (9 more replies)
0 siblings, 10 replies; 20+ messages in thread
From: Hongbo Li @ 2025-11-17 13:25 UTC (permalink / raw)
To: hsiangkao, chao, brauner, djwong, amir73il, joannelkoong
Cc: lihongbo22, linux-fsdevel, linux-erofs, linux-kernel
Enabling page cahe sharing in container scenarios has become increasingly
crucial, as it can significantly reduce memory usage. In previous efforts,
Hongzhen has done substantial work to push this feature into the EROFS
mainline. Due to other commitments, he hasn't been able to continue his
work recently, and I'm very pleased to build upon his work and continue
to refine this implementation.
This patch series is based on Hongzhen's original EROFS shared pagecache
implementation which was posted about half a year ago:
https://lore.kernel.org/all/20250301145002.2420830-1-hongzhen@linux.alibaba.com/T/#u
In addition to the forward-port, I have also fixed several bugs, resolved
some prerequisite dependencies and performed some minor cleanup.
(A recap of Hongzhen's original cover letter is below, edited slightly
for this serise:)
Background
==============
Currently, reading files with different paths (or names) but the same
content can consume multiple copies of the page cache, even if the
content of these caches is identical. For example, reading identical
files (e.g., *.so files) from two different minor versions of container
images can result in multiple copies of the same page cache, since
different containers have different mount points. Therefore, sharing
the page cache for files with the same content can save memory.
Proposal
==============
1. determining file identity
----------------------------
First, a way needs to be found to check whether the content of two files
is the same. Here, the xattr values associated with the file
fingerprints are assessed for consistency. When creating the EROFS
image, users can specify the name of the xattr for file fingerprints,
and the corresponding name will be stored in the packfile. The on-disk
`ishare_key_start` indicates the index of the xattr name within the
prefix xattrs:
```
struct erofs_super_block {
__u8 xattr_filter_reserved; /* reserved for xattr name filter */
- __u8 reserved[3];
+ __u8 ishare_key_start; /* start of ishare key */
+ __u8 reserved[2];
};
```
For example, users can specify the first long prefix as the name for the
file fingerprint as follows:
```
mkfs.erofs --ishare_key=trusted.erofs.fingerprint erofs.img ./dir
```
In this way, `trusted.erofs.fingerprint` serves as the name of the xattr
for the file fingerprint. The relevant patch for erofs-utils has been posted
in:
https://lore.kernel.org/all/20251114092845.207368-1-lihongbo22@huawei.com/
At the same time, for security reasons, this patch series only shares
files within the same domain, which is achieved by adding
"-o domain_id=xxxx" during the mounting process:
```
mount -t erofs -o domain_id=trusted.erofs.fingerprint erofs.img /mnt
```
If no domain ID is specified, it will fall back to the non-page cache
sharing mode.
2. Implementation
==================
2.1. file open & close
----------------------
When the file is opened, the ->private_data field of file A or file B is
set to point to an internal deduplicated file. When the actual read
occurs, the page cache of this deduplicated file will be accessed.
When the file is opened, if the corresponding erofs inode is newly
created, then perform the following actions:
1. add the erofs inode to the backing list of the deduplicated inode;
2. increase the reference count of the deduplicated inode.
The purpose of step 1 above is to ensure that when a real I/O operation
occurs, the deduplicated inode can locate one of the disk devices
(as the deduplicated inode itself is not bound to a specific device).
Step 2 is for managing the lifecycle of the deduplicated inode.
When the erofs inode is destroyed, the opposite actions mentioned above
will be taken.
2.2. file reading
-----------------
Assuming the deduplication inode's page cache is PGCache_dedup, there
are two possible scenarios when reading a file:
1) the content being read is already present in PGCache_dedup;
2) the content being read is not present in PGCache_dedup.
In the second scenario, it involves the iomap operation to read from the
disk.
2.2.1. reading existing data in PGCache_dedup
-------------------------------------------
In this case, the overall read flowchart is as follows (take ksys_read()
for example):
ksys_read
│
│
▼
...
│
│
▼
erofs_ishare_file_read_iter (switch to backing deduplicated file)
│
│
▼
read PGCache_dedup & return
At this point, the content in PGCache_dedup will be read directly and
returned.
2.2.2 reading non-existent content in PGCache_dedup
---------------------------------------------------
In this case, disk I/O operations will be involved. Taking the reading
of an uncompressed file as an example, here is the reading process:
ksys_read
│
│
▼
...
│
│
▼
erofs_ishare_file_read_iter (switch to backing deduplicated file)
│
│
▼
... (allocate pages)
│
│
▼
erofs_read_folio/erofs_readahead
│
│
▼
... (iomap)
│
│
▼
erofs_iomap_begin
│
│
▼
...
Iomap and the layers below will involve disk I/O operations. As
described in 2.1, the deduplicated inode itself is not bound to a
specific device. The deduplicated inode will select an erofs inode from
the backing list (by default, the first one) to complete the
corresponding iomap operation.
2.3. release page cache
-----------------------
Similar to overlayfs, when dropping the page cache via .fadvise, erofs
locates the deduplicated file and applies vfs_fadvise to that specific
file.
Effect
==================
I conducted experiments on two aspects across two different minor
versions of container images:
1. reading all files in two different minor versions of container images
2. run workloads or use the default entrypoint within the containers^[1]
Below is the memory usage for reading all files in two different minor
versions of container images:
+-------------------+------------------+-------------+---------------+
| Image | Page Cache Share | Memory (MB) | Memory |
| | | | Reduction (%) |
+-------------------+------------------+-------------+---------------+
| | No | 241 | - |
| redis +------------------+-------------+---------------+
| 7.2.4 & 7.2.5 | Yes | 163 | 33% |
+-------------------+------------------+-------------+---------------+
| | No | 872 | - |
| postgres +------------------+-------------+---------------+
| 16.1 & 16.2 | Yes | 630 | 28% |
+-------------------+------------------+-------------+---------------+
| | No | 2771 | - |
| tensorflow +------------------+-------------+---------------+
| 2.11.0 & 2.11.1 | Yes | 2340 | 16% |
+-------------------+------------------+-------------+---------------+
| | No | 926 | - |
| mysql +------------------+-------------+---------------+
| 8.0.11 & 8.0.12 | Yes | 735 | 21% |
+-------------------+------------------+-------------+---------------+
| | No | 390 | - |
| nginx +------------------+-------------+---------------+
| 7.2.4 & 7.2.5 | Yes | 219 | 44% |
+-------------------+------------------+-------------+---------------+
| tomcat | No | 924 | - |
| 10.1.25 & 10.1.26 +------------------+-------------+---------------+
| | Yes | 474 | 49% |
+-------------------+------------------+-------------+---------------+
Additionally, the table below shows the runtime memory usage of the
container:
+-------------------+------------------+-------------+---------------+
| Image | Page Cache Share | Memory (MB) | Memory |
| | | | Reduction (%) |
+-------------------+------------------+-------------+---------------+
| | No | 34.9 | - |
| redis +------------------+-------------+---------------+
| 7.2.4 & 7.2.5 | Yes | 33.6 | 4% |
+-------------------+------------------+-------------+---------------+
| | No | 149.1 | - |
| postgres +------------------+-------------+---------------+
| 16.1 & 16.2 | Yes | 95 | 37% |
+-------------------+------------------+-------------+---------------+
| | No | 1027.9 | - |
| tensorflow +------------------+-------------+---------------+
| 2.11.0 & 2.11.1 | Yes | 934.3 | 10% |
+-------------------+------------------+-------------+---------------+
| | No | 155.0 | - |
| mysql +------------------+-------------+---------------+
| 8.0.11 & 8.0.12 | Yes | 139.1 | 11% |
+-------------------+------------------+-------------+---------------+
| | No | 25.4 | - |
| nginx +------------------+-------------+---------------+
| 7.2.4 & 7.2.5 | Yes | 18.8 | 26% |
+-------------------+------------------+-------------+---------------+
| tomcat | No | 186 | - |
| 10.1.25 & 10.1.26 +------------------+-------------+---------------+
| | Yes | 99 | 47% |
+-------------------+------------------+-------------+---------------+
It can be observed that when reading all the files in the image, the
reduced memory usage varies from 16% to 49%, depending on the specific
image. Additionally, the container's runtime memory usage reduction
ranges from 4% to 47%.
[1] Below are the workload for these images:
- redis: redis-benchmark
- postgres: sysbench
- tensorflow: app.py of tensorflow.python.platform
- mysql: sysbench
- nginx: wrk
- tomcat: default entrypoint
Changes from v8:
- add review-by in patch 1 and patch 10.
- do some clean up in patch 2 and patch 4,6,9 as suggested by Xiang.
- add new patch 3 to export alloc_empty_backing_file.
- patch 5 only use xattr prefix id to record the ishare info, changed
config to EROFS_FS_PAGE_CACHE_SHARE and make it compatible.
- patch 7 use backing file helpers to alloc file when ishare file is
opened as suggested by Xiang.
- patch 8 remove erofs_read_{begin,end} as suggested by Xiang.
v8: https://lore.kernel.org/all/20251114095516.207555-1-lihongbo22@huawei.com/
v7: https://lore.kernel.org/all/20251021104815.70662-1-lihongbo22@huawei.com/
v6: https://lore.kernel.org/all/20250301145002.2420830-1-hongzhen@linux.alibaba.com/T/#u
v5: https://lore.kernel.org/all/20250105151208.3797385-1-hongzhen@linux.alibaba.com/
v4: https://lore.kernel.org/all/20240902110620.2202586-1-hongzhen@linux.alibaba.com/
v3: https://lore.kernel.org/all/20240828111959.3677011-1-hongzhen@linux.alibaba.com/
v2: https://lore.kernel.org/all/20240731080704.678259-1-hongzhen@linux.alibaba.com/
v1: https://lore.kernel.org/all/20240722065355.1396365-1-hongzhen@linux.alibaba.com/
Diffstat:
fs/erofs/Kconfig | 9 ++
fs/erofs/Makefile | 1 +
fs/erofs/data.c | 89 +++++++++----
fs/erofs/erofs_fs.h | 6 +-
fs/erofs/fscache.c | 13 --
fs/erofs/inode.c | 4 +
fs/erofs/internal.h | 50 ++++++++
fs/erofs/ishare.c | 283 +++++++++++++++++++++++++++++++++++++++++
fs/erofs/super.c | 53 +++++++-
fs/erofs/xattr.c | 15 +++
fs/erofs/zdata.c | 42 ++++--
fs/file_table.c | 1 +
fs/fuse/file.c | 4 +-
fs/iomap/buffered-io.c | 6 +-
include/linux/iomap.h | 8 +-
15 files changed, 524 insertions(+), 60 deletions(-)
create mode 100644 fs/erofs/ishare.c
--
2.22.0
^ permalink raw reply [flat|nested] 20+ messages in thread
* [PATCH v9 01/10] iomap: stash iomap read ctx in the private field of iomap_iter
2025-11-17 13:25 [PATCH v9 00/10] erofs: inode page cache share feature Hongbo Li
@ 2025-11-17 13:25 ` Hongbo Li
2025-11-17 17:08 ` Gao Xiang
2025-11-17 13:25 ` [PATCH v9 02/10] erofs: hold read context in iomap_iter if needed Hongbo Li
` (8 subsequent siblings)
9 siblings, 1 reply; 20+ messages in thread
From: Hongbo Li @ 2025-11-17 13:25 UTC (permalink / raw)
To: hsiangkao, chao, brauner, djwong, amir73il, joannelkoong
Cc: lihongbo22, linux-fsdevel, linux-erofs, linux-kernel
It's useful to get filesystem-specific information using the
existing private field in the @iomap_iter passed to iomap_{begin,end}
for advanced usage for iomap buffered reads, which is much like the
current iomap DIO.
For example, EROFS needs it to:
- implement an efficient page cache sharing feature, since iomap
needs to apply to anon inode page cache but we'd like to get the
backing inode/fs instead, so filesystem-specific private data is
needed to keep such information;
- pass in both struct page * and void * for inline data to avoid
kmap_to_page() usage (which is bogus).
Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Signed-off-by: Hongbo Li <lihongbo22@huawei.com>
---
fs/fuse/file.c | 4 ++--
fs/iomap/buffered-io.c | 6 ++++--
include/linux/iomap.h | 8 ++++----
3 files changed, 10 insertions(+), 8 deletions(-)
diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index 8275b6681b9b..98dd20f0bb53 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -973,7 +973,7 @@ static int fuse_read_folio(struct file *file, struct folio *folio)
return -EIO;
}
- iomap_read_folio(&fuse_iomap_ops, &ctx);
+ iomap_read_folio(&fuse_iomap_ops, &ctx, NULL);
fuse_invalidate_atime(inode);
return 0;
}
@@ -1075,7 +1075,7 @@ static void fuse_readahead(struct readahead_control *rac)
if (fuse_is_bad(inode))
return;
- iomap_readahead(&fuse_iomap_ops, &ctx);
+ iomap_readahead(&fuse_iomap_ops, &ctx, NULL);
}
static ssize_t fuse_cache_read_iter(struct kiocb *iocb, struct iov_iter *to)
diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c
index 6ae031ac8058..8e79303c074e 100644
--- a/fs/iomap/buffered-io.c
+++ b/fs/iomap/buffered-io.c
@@ -496,13 +496,14 @@ static int iomap_read_folio_iter(struct iomap_iter *iter,
}
void iomap_read_folio(const struct iomap_ops *ops,
- struct iomap_read_folio_ctx *ctx)
+ struct iomap_read_folio_ctx *ctx, void *private)
{
struct folio *folio = ctx->cur_folio;
struct iomap_iter iter = {
.inode = folio->mapping->host,
.pos = folio_pos(folio),
.len = folio_size(folio),
+ .private = private,
};
size_t bytes_pending = 0;
int ret;
@@ -560,13 +561,14 @@ static int iomap_readahead_iter(struct iomap_iter *iter,
* the filesystem to be reentered.
*/
void iomap_readahead(const struct iomap_ops *ops,
- struct iomap_read_folio_ctx *ctx)
+ struct iomap_read_folio_ctx *ctx, void *private)
{
struct readahead_control *rac = ctx->rac;
struct iomap_iter iter = {
.inode = rac->mapping->host,
.pos = readahead_pos(rac),
.len = readahead_length(rac),
+ .private = private,
};
size_t cur_bytes_pending;
diff --git a/include/linux/iomap.h b/include/linux/iomap.h
index 8b1ac08c7474..c3ecbbdb14e8 100644
--- a/include/linux/iomap.h
+++ b/include/linux/iomap.h
@@ -341,9 +341,9 @@ ssize_t iomap_file_buffered_write(struct kiocb *iocb, struct iov_iter *from,
const struct iomap_ops *ops,
const struct iomap_write_ops *write_ops, void *private);
void iomap_read_folio(const struct iomap_ops *ops,
- struct iomap_read_folio_ctx *ctx);
+ struct iomap_read_folio_ctx *ctx, void *private);
void iomap_readahead(const struct iomap_ops *ops,
- struct iomap_read_folio_ctx *ctx);
+ struct iomap_read_folio_ctx *ctx, void *private);
bool iomap_is_partially_uptodate(struct folio *, size_t from, size_t count);
struct folio *iomap_get_folio(struct iomap_iter *iter, loff_t pos, size_t len);
bool iomap_release_folio(struct folio *folio, gfp_t gfp_flags);
@@ -594,7 +594,7 @@ static inline void iomap_bio_read_folio(struct folio *folio,
.cur_folio = folio,
};
- iomap_read_folio(ops, &ctx);
+ iomap_read_folio(ops, &ctx, NULL);
}
static inline void iomap_bio_readahead(struct readahead_control *rac,
@@ -605,7 +605,7 @@ static inline void iomap_bio_readahead(struct readahead_control *rac,
.rac = rac,
};
- iomap_readahead(ops, &ctx);
+ iomap_readahead(ops, &ctx, NULL);
}
#endif /* CONFIG_BLOCK */
--
2.22.0
^ permalink raw reply related [flat|nested] 20+ messages in thread
* [PATCH v9 02/10] erofs: hold read context in iomap_iter if needed
2025-11-17 13:25 [PATCH v9 00/10] erofs: inode page cache share feature Hongbo Li
2025-11-17 13:25 ` [PATCH v9 01/10] iomap: stash iomap read ctx in the private field of iomap_iter Hongbo Li
@ 2025-11-17 13:25 ` Hongbo Li
2025-11-17 13:25 ` [PATCH v9 03/10] fs: Export alloc_empty_backing_file Hongbo Li
` (7 subsequent siblings)
9 siblings, 0 replies; 20+ messages in thread
From: Hongbo Li @ 2025-11-17 13:25 UTC (permalink / raw)
To: hsiangkao, chao, brauner, djwong, amir73il, joannelkoong
Cc: lihongbo22, linux-fsdevel, linux-erofs, linux-kernel
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>
---
fs/erofs/data.c | 67 +++++++++++++++++++++++++++++++++----------------
1 file changed, 46 insertions(+), 21 deletions(-)
diff --git a/fs/erofs/data.c b/fs/erofs/data.c
index bb13c4cb8455..71e23d91123d 100644
--- a/fs/erofs/data.c
+++ b/fs/erofs/data.c
@@ -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);
}
--
2.22.0
^ permalink raw reply related [flat|nested] 20+ messages in thread
* [PATCH v9 03/10] fs: Export alloc_empty_backing_file
2025-11-17 13:25 [PATCH v9 00/10] erofs: inode page cache share feature Hongbo Li
2025-11-17 13:25 ` [PATCH v9 01/10] iomap: stash iomap read ctx in the private field of iomap_iter Hongbo Li
2025-11-17 13:25 ` [PATCH v9 02/10] erofs: hold read context in iomap_iter if needed Hongbo Li
@ 2025-11-17 13:25 ` Hongbo Li
2025-11-17 13:25 ` [PATCH v9 04/10] erofs: move `struct erofs_anon_fs_type` to super.c Hongbo Li
` (6 subsequent siblings)
9 siblings, 0 replies; 20+ messages in thread
From: Hongbo Li @ 2025-11-17 13:25 UTC (permalink / raw)
To: hsiangkao, chao, brauner, djwong, amir73il, joannelkoong
Cc: lihongbo22, linux-fsdevel, linux-erofs, linux-kernel
There is no need to open nonexistent real files if backing files
couldn't be backed by real files (e.g., EROFS page cache sharing
doesn't need typical real files to open again).
Therefore, we export the alloc_empty_backing_file() helper, allowing
filesystems to dynamically set the backing file without real file
open. This is particularly useful for obtaining the correct @path
and @inode when calling file_user_path() and file_user_inode().
Signed-off-by: Hongbo Li <lihongbo22@huawei.com>
---
fs/file_table.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/fs/file_table.c b/fs/file_table.c
index b223d873e48b..7508f69a1839 100644
--- a/fs/file_table.c
+++ b/fs/file_table.c
@@ -308,6 +308,7 @@ struct file *alloc_empty_backing_file(int flags, const struct cred *cred)
ff->file.f_mode |= FMODE_BACKING | FMODE_NOACCOUNT;
return &ff->file;
}
+EXPORT_SYMBOL_GPL(alloc_empty_backing_file);
/**
* file_init_path - initialize a 'struct file' based on path
--
2.22.0
^ permalink raw reply related [flat|nested] 20+ messages in thread
* [PATCH v9 04/10] erofs: move `struct erofs_anon_fs_type` to super.c
2025-11-17 13:25 [PATCH v9 00/10] erofs: inode page cache share feature Hongbo Li
` (2 preceding siblings ...)
2025-11-17 13:25 ` [PATCH v9 03/10] fs: Export alloc_empty_backing_file Hongbo Li
@ 2025-11-17 13:25 ` Hongbo Li
2025-11-17 13:25 ` [PATCH v9 05/10] erofs: support user-defined fingerprint name Hongbo Li
` (5 subsequent siblings)
9 siblings, 0 replies; 20+ messages in thread
From: Hongbo Li @ 2025-11-17 13:25 UTC (permalink / raw)
To: hsiangkao, chao, brauner, djwong, amir73il, joannelkoong
Cc: lihongbo22, linux-fsdevel, linux-erofs, linux-kernel
From: Hongzhen Luo <hongzhen@linux.alibaba.com>
Move the `struct erofs_anon_fs_type` to the super.c and
expose it in preparation for the upcoming page cache share
feature.
Signed-off-by: Hongzhen Luo <hongzhen@linux.alibaba.com>
Signed-off-by: Hongbo Li <lihongbo22@huawei.com>
---
fs/erofs/fscache.c | 13 -------------
fs/erofs/internal.h | 2 ++
fs/erofs/super.c | 15 +++++++++++++++
3 files changed, 17 insertions(+), 13 deletions(-)
diff --git a/fs/erofs/fscache.c b/fs/erofs/fscache.c
index 362acf828279..2d1683479fc0 100644
--- a/fs/erofs/fscache.c
+++ b/fs/erofs/fscache.c
@@ -3,7 +3,6 @@
* Copyright (C) 2022, Alibaba Cloud
* Copyright (C) 2022, Bytedance Inc. All rights reserved.
*/
-#include <linux/pseudo_fs.h>
#include <linux/fscache.h>
#include "internal.h"
@@ -13,18 +12,6 @@ static LIST_HEAD(erofs_domain_list);
static LIST_HEAD(erofs_domain_cookies_list);
static struct vfsmount *erofs_pseudo_mnt;
-static int erofs_anon_init_fs_context(struct fs_context *fc)
-{
- return init_pseudo(fc, EROFS_SUPER_MAGIC) ? 0 : -ENOMEM;
-}
-
-static struct file_system_type erofs_anon_fs_type = {
- .owner = THIS_MODULE,
- .name = "pseudo_erofs",
- .init_fs_context = erofs_anon_init_fs_context,
- .kill_sb = kill_anon_super,
-};
-
struct erofs_fscache_io {
struct netfs_cache_resources cres;
struct iov_iter iter;
diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h
index f7f622836198..98fe652aea33 100644
--- a/fs/erofs/internal.h
+++ b/fs/erofs/internal.h
@@ -188,6 +188,8 @@ static inline bool erofs_is_fileio_mode(struct erofs_sb_info *sbi)
return IS_ENABLED(CONFIG_EROFS_FS_BACKED_BY_FILE) && sbi->dif0.file;
}
+extern struct file_system_type erofs_anon_fs_type;
+
static inline bool erofs_is_fscache_mode(struct super_block *sb)
{
return IS_ENABLED(CONFIG_EROFS_FS_ONDEMAND) &&
diff --git a/fs/erofs/super.c b/fs/erofs/super.c
index f3f8d8c066e4..0d88c04684b9 100644
--- a/fs/erofs/super.c
+++ b/fs/erofs/super.c
@@ -11,6 +11,7 @@
#include <linux/fs_parser.h>
#include <linux/exportfs.h>
#include <linux/backing-dev.h>
+#include <linux/pseudo_fs.h>
#include "xattr.h"
#define CREATE_TRACE_POINTS
@@ -920,6 +921,20 @@ static struct file_system_type erofs_fs_type = {
};
MODULE_ALIAS_FS("erofs");
+#if defined(CONFIG_EROFS_FS_ONDEMAND)
+static int erofs_anon_init_fs_context(struct fs_context *fc)
+{
+ return init_pseudo(fc, EROFS_SUPER_MAGIC) ? 0 : -ENOMEM;
+}
+
+struct file_system_type erofs_anon_fs_type = {
+ .owner = THIS_MODULE,
+ .name = "pseudo_erofs",
+ .init_fs_context = erofs_anon_init_fs_context,
+ .kill_sb = kill_anon_super,
+};
+#endif
+
static int __init erofs_module_init(void)
{
int err;
--
2.22.0
^ permalink raw reply related [flat|nested] 20+ messages in thread
* [PATCH v9 05/10] erofs: support user-defined fingerprint name
2025-11-17 13:25 [PATCH v9 00/10] erofs: inode page cache share feature Hongbo Li
` (3 preceding siblings ...)
2025-11-17 13:25 ` [PATCH v9 04/10] erofs: move `struct erofs_anon_fs_type` to super.c Hongbo Li
@ 2025-11-17 13:25 ` Hongbo Li
2025-11-17 17:26 ` Gao Xiang
2025-11-17 13:25 ` [PATCH v9 06/10] erofs: support domain-specific page cache share Hongbo Li
` (4 subsequent siblings)
9 siblings, 1 reply; 20+ messages in thread
From: Hongbo Li @ 2025-11-17 13:25 UTC (permalink / raw)
To: hsiangkao, chao, brauner, djwong, amir73il, joannelkoong
Cc: lihongbo22, linux-fsdevel, linux-erofs, linux-kernel
From: Hongzhen Luo <hongzhen@linux.alibaba.com>
When creating the EROFS image, users can specify the fingerprint name.
This is to prepare for the upcoming inode page cache share.
Signed-off-by: Hongzhen Luo <hongzhen@linux.alibaba.com>
Signed-off-by: Hongbo Li <lihongbo22@huawei.com>
---
fs/erofs/Kconfig | 9 +++++++++
fs/erofs/erofs_fs.h | 6 ++++--
fs/erofs/internal.h | 2 ++
fs/erofs/super.c | 5 +++--
fs/erofs/xattr.c | 15 +++++++++++++++
5 files changed, 33 insertions(+), 4 deletions(-)
diff --git a/fs/erofs/Kconfig b/fs/erofs/Kconfig
index d81f3318417d..c88b6d0714a4 100644
--- a/fs/erofs/Kconfig
+++ b/fs/erofs/Kconfig
@@ -194,3 +194,12 @@ config EROFS_FS_PCPU_KTHREAD_HIPRI
at higher priority.
If unsure, say N.
+
+config EROFS_FS_PAGE_CACHE_SHARE
+ bool "EROFS page cache share support (experimental)"
+ depends on EROFS_FS && EROFS_FS_XATTR && !EROFS_FS_ONDEMAND
+ help
+ This enables page cache sharing among inodes with identical
+ content fingerprints on the same device.
+
+ If unsure, say N.
diff --git a/fs/erofs/erofs_fs.h b/fs/erofs/erofs_fs.h
index 3d5738f80072..9b9fe1abe0b9 100644
--- a/fs/erofs/erofs_fs.h
+++ b/fs/erofs/erofs_fs.h
@@ -35,8 +35,9 @@
#define EROFS_FEATURE_INCOMPAT_XATTR_PREFIXES 0x00000040
#define EROFS_FEATURE_INCOMPAT_48BIT 0x00000080
#define EROFS_FEATURE_INCOMPAT_METABOX 0x00000100
+#define EROFS_FEATURE_INCOMPAT_ISHARE_KEY 0x00000200
#define EROFS_ALL_FEATURE_INCOMPAT \
- ((EROFS_FEATURE_INCOMPAT_METABOX << 1) - 1)
+ ((EROFS_FEATURE_INCOMPAT_ISHARE_KEY << 1) - 1)
#define EROFS_SB_EXTSLOT_SIZE 16
@@ -83,7 +84,8 @@ struct erofs_super_block {
__le32 xattr_prefix_start; /* start of long xattr prefixes */
__le64 packed_nid; /* nid of the special packed inode */
__u8 xattr_filter_reserved; /* reserved for xattr name filter */
- __u8 reserved[3];
+ __u8 ishare_xattr_prefix_id; /* indice the ishare key in prefix xattr */
+ __u8 reserved[2];
__le32 build_time; /* seconds added to epoch for mkfs time */
__le64 rootnid_8b; /* (48BIT on) nid of root directory */
__le64 reserved2;
diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h
index 98fe652aea33..3033252211ba 100644
--- a/fs/erofs/internal.h
+++ b/fs/erofs/internal.h
@@ -134,6 +134,7 @@ struct erofs_sb_info {
u32 xattr_blkaddr;
u32 xattr_prefix_start;
u8 xattr_prefix_count;
+ u8 ishare_xattr_pfx; /* ishare prefix xattr index */
struct erofs_xattr_prefix_item *xattr_prefixes;
unsigned int xattr_filter_reserved;
#endif
@@ -234,6 +235,7 @@ EROFS_FEATURE_FUNCS(dedupe, incompat, INCOMPAT_DEDUPE)
EROFS_FEATURE_FUNCS(xattr_prefixes, incompat, INCOMPAT_XATTR_PREFIXES)
EROFS_FEATURE_FUNCS(48bit, incompat, INCOMPAT_48BIT)
EROFS_FEATURE_FUNCS(metabox, incompat, INCOMPAT_METABOX)
+EROFS_FEATURE_FUNCS(ishare_key, incompat, INCOMPAT_ISHARE_KEY)
EROFS_FEATURE_FUNCS(sb_chksum, compat, COMPAT_SB_CHKSUM)
EROFS_FEATURE_FUNCS(xattr_filter, compat, COMPAT_XATTR_FILTER)
EROFS_FEATURE_FUNCS(shared_ea_in_metabox, compat, COMPAT_SHARED_EA_IN_METABOX)
diff --git a/fs/erofs/super.c b/fs/erofs/super.c
index 0d88c04684b9..80f032cb2cc3 100644
--- a/fs/erofs/super.c
+++ b/fs/erofs/super.c
@@ -298,6 +298,9 @@ static int erofs_read_superblock(struct super_block *sb)
if (ret)
goto out;
}
+ if (erofs_sb_has_ishare_key(sbi))
+ sbi->ishare_xattr_pfx =
+ dsb->ishare_xattr_prefix_id & EROFS_XATTR_LONG_PREFIX_MASK;
ret = -EINVAL;
sbi->feature_incompat = le32_to_cpu(dsb->feature_incompat);
@@ -339,7 +342,6 @@ static int erofs_read_superblock(struct super_block *sb)
return -EFSCORRUPTED; /* self-loop detection */
}
sbi->inos = le64_to_cpu(dsb->inos);
-
sbi->epoch = (s64)le64_to_cpu(dsb->epoch);
sbi->fixed_nsec = le32_to_cpu(dsb->fixed_nsec);
super_set_uuid(sb, (void *)dsb->uuid, sizeof(dsb->uuid));
@@ -737,7 +739,6 @@ static int erofs_fc_fill_super(struct super_block *sb, struct fs_context *fc)
err = erofs_xattr_prefixes_init(sb);
if (err)
return err;
-
erofs_set_sysfs_name(sb);
err = erofs_register_sysfs(sb);
if (err)
diff --git a/fs/erofs/xattr.c b/fs/erofs/xattr.c
index 396536d9a862..6cb76313c14c 100644
--- a/fs/erofs/xattr.c
+++ b/fs/erofs/xattr.c
@@ -519,6 +519,21 @@ int erofs_xattr_prefixes_init(struct super_block *sb)
}
erofs_put_metabuf(&buf);
+ if (!ret && erofs_sb_has_ishare_key(sbi)) {
+ struct erofs_xattr_long_prefix *new_pfx, *pfx =
+ pfs[sbi->ishare_xattr_pfx].prefix;
+
+ new_pfx = krealloc(pfx,
+ sizeof(struct erofs_xattr_long_prefix) +
+ pfs[sbi->ishare_xattr_pfx].infix_len + 1,
+ GFP_KERNEL);
+ if (new_pfx) {
+ new_pfx->infix[pfs[sbi->ishare_xattr_pfx].infix_len] = '\0';
+ pfs[sbi->ishare_xattr_pfx].prefix = new_pfx;
+ } else {
+ ret = -ENOMEM;
+ }
+ }
sbi->xattr_prefixes = pfs;
if (ret)
erofs_xattr_prefixes_cleanup(sb);
--
2.22.0
^ permalink raw reply related [flat|nested] 20+ messages in thread
* [PATCH v9 06/10] erofs: support domain-specific page cache share
2025-11-17 13:25 [PATCH v9 00/10] erofs: inode page cache share feature Hongbo Li
` (4 preceding siblings ...)
2025-11-17 13:25 ` [PATCH v9 05/10] erofs: support user-defined fingerprint name Hongbo Li
@ 2025-11-17 13:25 ` Hongbo Li
2025-11-17 13:25 ` [PATCH v9 07/10] erofs: introduce the page cache share feature Hongbo Li
` (3 subsequent siblings)
9 siblings, 0 replies; 20+ messages in thread
From: Hongbo Li @ 2025-11-17 13:25 UTC (permalink / raw)
To: hsiangkao, chao, brauner, djwong, amir73il, joannelkoong
Cc: lihongbo22, linux-fsdevel, linux-erofs, linux-kernel
From: Hongzhen Luo <hongzhen@linux.alibaba.com>
Only files in the same domain will share the page cache. Also modify
the sysfs related content in preparation for the upcoming page cache
share feature.
Signed-off-by: Hongzhen Luo <hongzhen@linux.alibaba.com>
Signed-off-by: Hongbo Li <lihongbo22@huawei.com>
---
fs/erofs/super.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/fs/erofs/super.c b/fs/erofs/super.c
index 80f032cb2cc3..9a5e3f9dcd0d 100644
--- a/fs/erofs/super.c
+++ b/fs/erofs/super.c
@@ -517,6 +517,8 @@ static int erofs_fc_parse_param(struct fs_context *fc,
if (!sbi->fsid)
return -ENOMEM;
break;
+#endif
+#if defined(CONFIG_EROFS_FS_ONDEMAND) || defined(CONFIG_EROFS_FS_PAGE_CACHE_SHARE)
case Opt_domain_id:
kfree(sbi->domain_id);
sbi->domain_id = kstrdup(param->string, GFP_KERNEL);
@@ -617,7 +619,7 @@ static void erofs_set_sysfs_name(struct super_block *sb)
{
struct erofs_sb_info *sbi = EROFS_SB(sb);
- if (sbi->domain_id)
+ if (sbi->domain_id && !erofs_sb_has_ishare_key(sbi))
super_set_sysfs_name_generic(sb, "%s,%s", sbi->domain_id,
sbi->fsid);
else if (sbi->fsid)
@@ -1034,6 +1036,8 @@ static int erofs_show_options(struct seq_file *seq, struct dentry *root)
#ifdef CONFIG_EROFS_FS_ONDEMAND
if (sbi->fsid)
seq_printf(seq, ",fsid=%s", sbi->fsid);
+#endif
+#if defined(CONFIG_EROFS_FS_ONDEMAND) || defined(CONFIG_EROFS_FS_PAGE_CACHE_SHARE)
if (sbi->domain_id)
seq_printf(seq, ",domain_id=%s", sbi->domain_id);
#endif
--
2.22.0
^ permalink raw reply related [flat|nested] 20+ messages in thread
* [PATCH v9 07/10] erofs: introduce the page cache share feature
2025-11-17 13:25 [PATCH v9 00/10] erofs: inode page cache share feature Hongbo Li
` (5 preceding siblings ...)
2025-11-17 13:25 ` [PATCH v9 06/10] erofs: support domain-specific page cache share Hongbo Li
@ 2025-11-17 13:25 ` Hongbo Li
2025-11-17 13:25 ` [PATCH v9 08/10] erofs: support unencoded inodes for page cache share Hongbo Li
` (2 subsequent siblings)
9 siblings, 0 replies; 20+ messages in thread
From: Hongbo Li @ 2025-11-17 13:25 UTC (permalink / raw)
To: hsiangkao, chao, brauner, djwong, amir73il, joannelkoong
Cc: lihongbo22, linux-fsdevel, linux-erofs, linux-kernel
From: Hongzhen Luo <hongzhen@linux.alibaba.com>
Currently, reading files with different paths (or names) but the same
content will consume multiple copies of the page cache, even if the
content of these page caches is the same. For example, reading
identical files (e.g., *.so files) from two different minor versions of
container images will cost multiple copies of the same page cache,
since different containers have different mount points. Therefore,
sharing the page cache for files with the same content can save memory.
This introduces the page cache share feature in erofs. It allocate a
deduplicated inode and use its page cache as shared. Reads for files
with identical content will ultimately be routed to the page cache of
the deduplicated inode. In this way, a single page cache satisfies
multiple read requests for different files with the same contents.
Signed-off-by: Hongzhen Luo <hongzhen@linux.alibaba.com>
Signed-off-by: Hongbo Li <lihongbo22@huawei.com>
---
fs/erofs/Makefile | 1 +
fs/erofs/internal.h | 29 ++++++
fs/erofs/ishare.c | 241 ++++++++++++++++++++++++++++++++++++++++++++
fs/erofs/super.c | 31 +++++-
4 files changed, 300 insertions(+), 2 deletions(-)
create mode 100644 fs/erofs/ishare.c
diff --git a/fs/erofs/Makefile b/fs/erofs/Makefile
index 549abc424763..a80e1762b607 100644
--- a/fs/erofs/Makefile
+++ b/fs/erofs/Makefile
@@ -10,3 +10,4 @@ erofs-$(CONFIG_EROFS_FS_ZIP_ZSTD) += decompressor_zstd.o
erofs-$(CONFIG_EROFS_FS_ZIP_ACCEL) += decompressor_crypto.o
erofs-$(CONFIG_EROFS_FS_BACKED_BY_FILE) += fileio.o
erofs-$(CONFIG_EROFS_FS_ONDEMAND) += fscache.o
+erofs-$(CONFIG_EROFS_FS_PAGE_CACHE_SHARE) += ishare.o
diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h
index 3033252211ba..93ad34f2b488 100644
--- a/fs/erofs/internal.h
+++ b/fs/erofs/internal.h
@@ -304,6 +304,22 @@ struct erofs_inode {
};
#endif /* CONFIG_EROFS_FS_ZIP */
};
+#ifdef CONFIG_EROFS_FS_PAGE_CACHE_SHARE
+ union {
+ /* internal dedup inode */
+ struct {
+ char *fingerprint;
+ spinlock_t lock;
+ /* all backing inodes */
+ struct list_head backing_head;
+ };
+
+ struct {
+ struct inode *ishare;
+ struct list_head backing_link;
+ };
+ };
+#endif
/* the corresponding vfs inode */
struct inode vfs_inode;
};
@@ -410,6 +426,7 @@ extern const struct inode_operations erofs_dir_iops;
extern const struct file_operations erofs_file_fops;
extern const struct file_operations erofs_dir_fops;
+extern const struct file_operations erofs_ishare_fops;
extern const struct iomap_ops z_erofs_iomap_report_ops;
@@ -541,6 +558,18 @@ static inline struct bio *erofs_fscache_bio_alloc(struct erofs_map_dev *mdev) {
static inline void erofs_fscache_submit_bio(struct bio *bio) {}
#endif
+#ifdef CONFIG_EROFS_FS_PAGE_CACHE_SHARE
+int erofs_ishare_init(struct super_block *sb);
+void erofs_ishare_exit(struct super_block *sb);
+bool erofs_ishare_fill_inode(struct inode *inode);
+void erofs_ishare_free_inode(struct inode *inode);
+#else
+static inline int erofs_ishare_init(struct super_block *sb) { return 0; }
+static inline void erofs_ishare_exit(struct super_block *sb) {}
+static inline bool erofs_ishare_fill_inode(struct inode *inode) { return false; }
+static inline void erofs_ishare_free_inode(struct inode *inode) {}
+#endif // CONFIG_EROFS_FS_PAGE_CACHE_SHARE
+
long erofs_ioctl(struct file *filp, unsigned int cmd, unsigned long arg);
long erofs_compat_ioctl(struct file *filp, unsigned int cmd,
unsigned long arg);
diff --git a/fs/erofs/ishare.c b/fs/erofs/ishare.c
new file mode 100644
index 000000000000..f386efb260da
--- /dev/null
+++ b/fs/erofs/ishare.c
@@ -0,0 +1,241 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2024, Alibaba Cloud
+ */
+#include <linux/xxhash.h>
+#include <linux/refcount.h>
+#include <linux/mount.h>
+#include <linux/mutex.h>
+#include <linux/ramfs.h>
+#include "internal.h"
+#include "xattr.h"
+
+#include "../internal.h"
+
+static DEFINE_MUTEX(erofs_ishare_lock);
+static struct vfsmount *erofs_ishare_mnt;
+static refcount_t erofs_ishare_supers;
+
+int erofs_ishare_init(struct super_block *sb)
+{
+ struct vfsmount *mnt = NULL;
+ struct erofs_sb_info *sbi = EROFS_SB(sb);
+
+ if (!erofs_sb_has_ishare_key(sbi))
+ return 0;
+
+ mutex_lock(&erofs_ishare_lock);
+ if (erofs_ishare_mnt) {
+ refcount_inc(&erofs_ishare_supers);
+ } else {
+ mnt = kern_mount(&erofs_anon_fs_type);
+ if (!IS_ERR(mnt)) {
+ erofs_ishare_mnt = mnt;
+ refcount_set(&erofs_ishare_supers, 1);
+ }
+ }
+ mutex_unlock(&erofs_ishare_lock);
+ return IS_ERR(mnt) ? PTR_ERR(mnt) : 0;
+}
+
+void erofs_ishare_exit(struct super_block *sb)
+{
+ struct erofs_sb_info *sbi = EROFS_SB(sb);
+ struct vfsmount *tmp;
+
+ if (!erofs_sb_has_ishare_key(sbi) || !erofs_ishare_mnt)
+ return;
+
+ mutex_lock(&erofs_ishare_lock);
+ if (refcount_dec_and_test(&erofs_ishare_supers)) {
+ tmp = erofs_ishare_mnt;
+ erofs_ishare_mnt = NULL;
+ mutex_unlock(&erofs_ishare_lock);
+ kern_unmount(tmp);
+ mutex_lock(&erofs_ishare_lock);
+ }
+ mutex_unlock(&erofs_ishare_lock);
+}
+
+static int erofs_ishare_iget5_eq(struct inode *inode, void *data)
+{
+ struct erofs_inode *vi = EROFS_I(inode);
+
+ return vi->fingerprint && memcmp(vi->fingerprint, data,
+ sizeof(size_t) + *(size_t *)data) == 0;
+}
+
+static int erofs_ishare_iget5_set(struct inode *inode, void *data)
+{
+ struct erofs_inode *vi = EROFS_I(inode);
+
+ vi->fingerprint = data;
+ INIT_LIST_HEAD(&vi->backing_head);
+ spin_lock_init(&vi->lock);
+ return 0;
+}
+
+bool erofs_ishare_fill_inode(struct inode *inode)
+{
+ struct erofs_sb_info *sbi = EROFS_SB(inode->i_sb);
+ struct erofs_xattr_prefix_item *ishare_prefix;
+ struct erofs_inode *vi = EROFS_I(inode);
+ struct inode *idedup;
+ /*
+ * fingerprint layout:
+ * fingerprint length + fingerprint content (xattr_value + domain_id)
+ */
+ char *ishare_key, *fingerprint;
+ ssize_t ishare_vlen;
+ unsigned long hash;
+ int key_idx;
+
+ if (!sbi->domain_id || !erofs_sb_has_ishare_key(sbi))
+ return false;
+
+ ishare_prefix = sbi->xattr_prefixes + sbi->ishare_xattr_pfx;
+ ishare_key = ishare_prefix->prefix->infix;
+ key_idx = ishare_prefix->prefix->base_index;
+ ishare_vlen = erofs_getxattr(inode, key_idx, ishare_key, NULL, 0);
+ if (ishare_vlen <= 0 || ishare_vlen > (1 << sbi->blkszbits))
+ return false;
+
+ fingerprint = kmalloc(sizeof(ssize_t) + ishare_vlen +
+ strlen(sbi->domain_id), GFP_KERNEL);
+ if (!fingerprint)
+ return false;
+
+ *(ssize_t *)fingerprint = ishare_vlen + strlen(sbi->domain_id);
+ if (ishare_vlen != erofs_getxattr(inode, key_idx, ishare_key,
+ fingerprint + sizeof(ssize_t),
+ ishare_vlen)) {
+ kfree(fingerprint);
+ return false;
+ }
+
+ memcpy(fingerprint + sizeof(ssize_t) + ishare_vlen,
+ sbi->domain_id, strlen(sbi->domain_id));
+ hash = xxh32(fingerprint + sizeof(ssize_t),
+ ishare_vlen + strlen(sbi->domain_id), hash);
+ idedup = iget5_locked(erofs_ishare_mnt->mnt_sb, hash,
+ erofs_ishare_iget5_eq, erofs_ishare_iget5_set,
+ fingerprint);
+ if (!idedup) {
+ kfree(fingerprint);
+ return false;
+ }
+
+ INIT_LIST_HEAD(&vi->backing_link);
+ vi->ishare = idedup;
+ spin_lock(&EROFS_I(idedup)->lock);
+ list_add(&vi->backing_link, &EROFS_I(idedup)->backing_head);
+ spin_unlock(&EROFS_I(idedup)->lock);
+ if (!(idedup->i_state & I_NEW)) {
+ kfree(fingerprint);
+ return true;
+ }
+ if (erofs_inode_is_data_compressed(vi->datalayout))
+ idedup->i_mapping->a_ops = &z_erofs_aops;
+ else
+ idedup->i_mapping->a_ops = &erofs_aops;
+ idedup->i_mode = vi->vfs_inode.i_mode;
+ i_size_write(idedup, vi->vfs_inode.i_size);
+ unlock_new_inode(idedup);
+ return true;
+}
+
+void erofs_ishare_free_inode(struct inode *inode)
+{
+ struct erofs_inode *vi = EROFS_I(inode);
+ struct inode *idedup = vi->ishare;
+
+ if (!idedup)
+ return;
+ spin_lock(&EROFS_I(idedup)->lock);
+ list_del(&vi->backing_link);
+ spin_unlock(&EROFS_I(idedup)->lock);
+ iput(idedup);
+ vi->ishare = NULL;
+}
+
+static int erofs_ishare_file_open(struct inode *inode, struct file *file)
+{
+ struct file *realfile;
+ struct inode *dedup;
+
+ dedup = EROFS_I(inode)->ishare;
+ if (!dedup)
+ return -EINVAL;
+
+ realfile = alloc_empty_backing_file(O_RDONLY|O_NOATIME, current_cred());
+ if (IS_ERR(realfile))
+ return PTR_ERR(realfile);
+ ihold(dedup);
+ realfile->f_op = &erofs_file_fops;
+ realfile->f_inode = dedup;
+ realfile->f_mapping = dedup->i_mapping;
+ path_get(&file->f_path);
+ backing_file_set_user_path(realfile, &file->f_path);
+
+ file_ra_state_init(&realfile->f_ra, file->f_mapping);
+ realfile->private_data = EROFS_I(inode);
+ file->private_data = realfile;
+ return 0;
+}
+
+static int erofs_ishare_file_release(struct inode *inode, struct file *file)
+{
+ struct file *realfile = file->private_data;
+
+ if (!realfile)
+ return -EINVAL;
+ iput(realfile->f_inode);
+ fput(realfile);
+ file->private_data = NULL;
+ return 0;
+}
+
+static ssize_t erofs_ishare_file_read_iter(struct kiocb *iocb,
+ struct iov_iter *to)
+{
+ struct file *realfile = iocb->ki_filp->private_data;
+ struct inode *inode = file_inode(iocb->ki_filp);
+ struct kiocb dedup_iocb;
+ ssize_t nread;
+
+ if (!realfile)
+ return -EINVAL;
+ if (!iov_iter_count(to))
+ return 0;
+
+ /* fallback to the original file in DAX or DIRECT mode */
+ if (IS_DAX(inode) || (iocb->ki_flags & IOCB_DIRECT))
+ realfile = iocb->ki_filp;
+
+ kiocb_clone(&dedup_iocb, iocb, realfile);
+ nread = filemap_read(&dedup_iocb, to, 0);
+ iocb->ki_pos = dedup_iocb.ki_pos;
+ file_accessed(iocb->ki_filp);
+ return nread;
+}
+
+static int erofs_ishare_mmap(struct file *file, struct vm_area_struct *vma)
+{
+ struct file *realfile = file->private_data;
+
+ if (!realfile)
+ return -EINVAL;
+
+ vma_set_file(vma, realfile);
+ return generic_file_readonly_mmap(file, vma);
+}
+
+const struct file_operations erofs_ishare_fops = {
+ .open = erofs_ishare_file_open,
+ .llseek = generic_file_llseek,
+ .read_iter = erofs_ishare_file_read_iter,
+ .mmap = erofs_ishare_mmap,
+ .release = erofs_ishare_file_release,
+ .get_unmapped_area = thp_get_unmapped_area,
+ .splice_read = filemap_splice_read,
+};
diff --git a/fs/erofs/super.c b/fs/erofs/super.c
index 9a5e3f9dcd0d..37e060dd5aff 100644
--- a/fs/erofs/super.c
+++ b/fs/erofs/super.c
@@ -746,6 +746,10 @@ static int erofs_fc_fill_super(struct super_block *sb, struct fs_context *fc)
if (err)
return err;
+ err = erofs_ishare_init(sb);
+ if (err)
+ return err;
+
sbi->dir_ra_bytes = EROFS_DIR_RA_BYTES;
erofs_info(sb, "mounted with root inode @ nid %llu.", sbi->root_nid);
return 0;
@@ -906,6 +910,7 @@ static void erofs_put_super(struct super_block *sb)
{
struct erofs_sb_info *const sbi = EROFS_SB(sb);
+ erofs_ishare_exit(sb);
erofs_unregister_sysfs(sb);
erofs_shrinker_unregister(sb);
erofs_xattr_prefixes_cleanup(sb);
@@ -924,10 +929,31 @@ static struct file_system_type erofs_fs_type = {
};
MODULE_ALIAS_FS("erofs");
-#if defined(CONFIG_EROFS_FS_ONDEMAND)
+#if defined(CONFIG_EROFS_FS_ONDEMAND) || defined(CONFIG_EROFS_FS_PAGE_CACHE_SHARE)
+static void erofs_free_anon_inode(struct inode *inode)
+{
+ struct erofs_inode *vi = EROFS_I(inode);
+
+#ifdef CONFIG_EROFS_FS_PAGE_CACHE_SHARE
+ kfree(vi->fingerprint);
+#endif
+ kmem_cache_free(erofs_inode_cachep, vi);
+}
+
+static const struct super_operations erofs_anon_sops = {
+ .alloc_inode = erofs_alloc_inode,
+ .free_inode = erofs_free_anon_inode,
+};
+
static int erofs_anon_init_fs_context(struct fs_context *fc)
{
- return init_pseudo(fc, EROFS_SUPER_MAGIC) ? 0 : -ENOMEM;
+ struct pseudo_fs_context *ctx;
+
+ ctx = init_pseudo(fc, EROFS_SUPER_MAGIC);
+ if (ctx)
+ ctx->ops = &erofs_anon_sops;
+
+ return ctx ? 0 : -ENOMEM;
}
struct file_system_type erofs_anon_fs_type = {
@@ -1053,6 +1079,7 @@ static void erofs_evict_inode(struct inode *inode)
dax_break_layout_final(inode);
#endif
+ erofs_ishare_free_inode(inode);
truncate_inode_pages_final(&inode->i_data);
clear_inode(inode);
}
--
2.22.0
^ permalink raw reply related [flat|nested] 20+ messages in thread
* [PATCH v9 08/10] erofs: support unencoded inodes for page cache share
2025-11-17 13:25 [PATCH v9 00/10] erofs: inode page cache share feature Hongbo Li
` (6 preceding siblings ...)
2025-11-17 13:25 ` [PATCH v9 07/10] erofs: introduce the page cache share feature Hongbo Li
@ 2025-11-17 13:25 ` Hongbo Li
2025-11-18 2:13 ` Hongbo Li
2025-11-17 13:25 ` [PATCH v9 09/10] erofs: support compressed " Hongbo Li
2025-11-17 13:25 ` [PATCH v9 10/10] erofs: implement .fadvise " Hongbo Li
9 siblings, 1 reply; 20+ messages in thread
From: Hongbo Li @ 2025-11-17 13:25 UTC (permalink / raw)
To: hsiangkao, chao, brauner, djwong, amir73il, joannelkoong
Cc: lihongbo22, linux-fsdevel, linux-erofs, linux-kernel
This patch adds inode page cache sharing functionality for unencoded
files.
I conducted experiments in the container environment. Below is the
memory usage for reading all files in two different minor versions
of container images:
+-------------------+------------------+-------------+---------------+
| Image | Page Cache Share | Memory (MB) | Memory |
| | | | Reduction (%) |
+-------------------+------------------+-------------+---------------+
| | No | 241 | - |
| redis +------------------+-------------+---------------+
| 7.2.4 & 7.2.5 | Yes | 163 | 33% |
+-------------------+------------------+-------------+---------------+
| | No | 872 | - |
| postgres +------------------+-------------+---------------+
| 16.1 & 16.2 | Yes | 630 | 28% |
+-------------------+------------------+-------------+---------------+
| | No | 2771 | - |
| tensorflow +------------------+-------------+---------------+
| 2.11.0 & 2.11.1 | Yes | 2340 | 16% |
+-------------------+------------------+-------------+---------------+
| | No | 926 | - |
| mysql +------------------+-------------+---------------+
| 8.0.11 & 8.0.12 | Yes | 735 | 21% |
+-------------------+------------------+-------------+---------------+
| | No | 390 | - |
| nginx +------------------+-------------+---------------+
| 7.2.4 & 7.2.5 | Yes | 219 | 44% |
+-------------------+------------------+-------------+---------------+
| tomcat | No | 924 | - |
| 10.1.25 & 10.1.26 +------------------+-------------+---------------+
| | Yes | 474 | 49% |
+-------------------+------------------+-------------+---------------+
Additionally, the table below shows the runtime memory usage of the
container:
+-------------------+------------------+-------------+---------------+
| Image | Page Cache Share | Memory (MB) | Memory |
| | | | Reduction (%) |
+-------------------+------------------+-------------+---------------+
| | No | 35 | - |
| redis +------------------+-------------+---------------+
| 7.2.4 & 7.2.5 | Yes | 28 | 20% |
+-------------------+------------------+-------------+---------------+
| | No | 149 | - |
| postgres +------------------+-------------+---------------+
| 16.1 & 16.2 | Yes | 95 | 37% |
+-------------------+------------------+-------------+---------------+
| | No | 1028 | - |
| tensorflow +------------------+-------------+---------------+
| 2.11.0 & 2.11.1 | Yes | 930 | 10% |
+-------------------+------------------+-------------+---------------+
| | No | 155 | - |
| mysql +------------------+-------------+---------------+
| 8.0.11 & 8.0.12 | Yes | 132 | 15% |
+-------------------+------------------+-------------+---------------+
| | No | 25 | - |
| nginx +------------------+-------------+---------------+
| 7.2.4 & 7.2.5 | Yes | 20 | 20% |
+-------------------+------------------+-------------+---------------+
| tomcat | No | 186 | - |
| 10.1.25 & 10.1.26 +------------------+-------------+---------------+
| | Yes | 98 | 48% |
+-------------------+------------------+-------------+---------------+
Co-developed-by: Hongzhen Luo <hongzhen@linux.alibaba.com>
Signed-off-by: Hongzhen Luo <hongzhen@linux.alibaba.com>
Signed-off-by: Hongbo Li <lihongbo22@huawei.com>
---
fs/erofs/data.c | 30 +++++++++++++++++++++++-------
fs/erofs/inode.c | 4 ++++
fs/erofs/internal.h | 17 +++++++++++++++++
fs/erofs/ishare.c | 31 +++++++++++++++++++++++++++++++
4 files changed, 75 insertions(+), 7 deletions(-)
diff --git a/fs/erofs/data.c b/fs/erofs/data.c
index 71e23d91123d..862df0c7ceb7 100644
--- a/fs/erofs/data.c
+++ b/fs/erofs/data.c
@@ -269,6 +269,7 @@ void erofs_onlinefolio_end(struct folio *folio, int err, bool dirty)
struct erofs_iomap_iter_ctx {
struct page *page;
void *base;
+ struct inode *realinode;
};
static int erofs_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
@@ -276,14 +277,15 @@ static int erofs_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
{
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 inode *realinode = ctx ? ctx->realinode : inode;
+ struct super_block *sb = realinode->i_sb;
struct erofs_map_blocks map;
struct erofs_map_dev mdev;
int ret;
map.m_la = offset;
map.m_llen = length;
- ret = erofs_map_blocks(inode, &map);
+ ret = erofs_map_blocks(realinode, &map);
if (ret < 0)
return ret;
@@ -296,7 +298,7 @@ static int erofs_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
return 0;
}
- if (!(map.m_flags & EROFS_MAP_META) || !erofs_inode_in_metabox(inode)) {
+ if (!(map.m_flags & EROFS_MAP_META) || !erofs_inode_in_metabox(realinode)) {
mdev = (struct erofs_map_dev) {
.m_deviceid = map.m_deviceid,
.m_pa = map.m_pa,
@@ -322,7 +324,7 @@ static int erofs_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
void *ptr;
ptr = erofs_read_metabuf(&buf, sb, map.m_pa,
- erofs_inode_in_metabox(inode));
+ erofs_inode_in_metabox(realinode));
if (IS_ERR(ptr))
return PTR_ERR(ptr);
iomap->inline_data = ptr;
@@ -379,30 +381,42 @@ int erofs_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
*/
static int erofs_read_folio(struct file *file, struct folio *folio)
{
+ struct inode *inode = folio_inode(folio);
struct iomap_read_folio_ctx read_ctx = {
.ops = &iomap_bio_read_ops,
.cur_folio = folio,
};
- struct erofs_iomap_iter_ctx iter_ctx = {};
+ struct erofs_iomap_iter_ctx iter_ctx = {
+ .realinode = erofs_ishare_iget(inode),
+ };
+ if (!iter_ctx.realinode)
+ return -EIO;
trace_erofs_read_folio(folio, true);
iomap_read_folio(&erofs_iomap_ops, &read_ctx, &iter_ctx);
+ erofs_ishare_iput(iter_ctx.realinode);
return 0;
}
static void erofs_readahead(struct readahead_control *rac)
{
+ struct inode *inode = rac->mapping->host;
struct iomap_read_folio_ctx read_ctx = {
.ops = &iomap_bio_read_ops,
.rac = rac,
};
- struct erofs_iomap_iter_ctx iter_ctx = {};
+ struct erofs_iomap_iter_ctx iter_ctx = {
+ .realinode = erofs_ishare_iget(inode),
+ };
+ if (!iter_ctx.realinode)
+ return;
trace_erofs_readahead(rac->mapping->host, readahead_index(rac),
readahead_count(rac), true);
iomap_readahead(&erofs_iomap_ops, &read_ctx, &iter_ctx);
+ erofs_ishare_iput(iter_ctx.realinode);
}
static sector_t erofs_bmap(struct address_space *mapping, sector_t block)
@@ -423,7 +437,9 @@ static ssize_t erofs_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
return dax_iomap_rw(iocb, to, &erofs_iomap_ops);
#endif
if ((iocb->ki_flags & IOCB_DIRECT) && inode->i_sb->s_bdev) {
- struct erofs_iomap_iter_ctx iter_ctx = {};
+ struct erofs_iomap_iter_ctx iter_ctx = {
+ .realinode = inode,
+ };
return iomap_dio_rw(iocb, to, &erofs_iomap_ops,
NULL, 0, &iter_ctx, 0);
diff --git a/fs/erofs/inode.c b/fs/erofs/inode.c
index cb780c095d28..3be4614d1add 100644
--- a/fs/erofs/inode.c
+++ b/fs/erofs/inode.c
@@ -215,6 +215,10 @@ static int erofs_fill_inode(struct inode *inode)
case S_IFREG:
inode->i_op = &erofs_generic_iops;
inode->i_fop = &erofs_file_fops;
+#ifdef CONFIG_EROFS_FS_PAGE_CACHE_SHARE
+ if (erofs_ishare_fill_inode(inode))
+ inode->i_fop = &erofs_ishare_fops;
+#endif
break;
case S_IFDIR:
inode->i_op = &erofs_dir_iops;
diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h
index 93ad34f2b488..37b536eebc3d 100644
--- a/fs/erofs/internal.h
+++ b/fs/erofs/internal.h
@@ -197,6 +197,19 @@ static inline bool erofs_is_fscache_mode(struct super_block *sb)
!erofs_is_fileio_mode(EROFS_SB(sb)) && !sb->s_bdev;
}
+#if defined(CONFIG_EROFS_FS_INODE_SHARE)
+static inline bool erofs_is_ishare_inode(struct inode *inode)
+{
+ /* we have assumed FS_ONDEMAND is excluded with FS_INODE_SHARE feature */
+ return inode->i_sb->s_type == &erofs_anon_fs_type;
+}
+#else
+static inline bool erofs_is_ishare_inode(struct inode *inode)
+{
+ return false;
+}
+#endif
+
enum {
EROFS_ZIP_CACHE_DISABLED,
EROFS_ZIP_CACHE_READAHEAD,
@@ -563,11 +576,15 @@ int erofs_ishare_init(struct super_block *sb);
void erofs_ishare_exit(struct super_block *sb);
bool erofs_ishare_fill_inode(struct inode *inode);
void erofs_ishare_free_inode(struct inode *inode);
+struct inode *erofs_ishare_iget(struct inode *inode);
+void erofs_ishare_iput(struct inode *realinode);
#else
static inline int erofs_ishare_init(struct super_block *sb) { return 0; }
static inline void erofs_ishare_exit(struct super_block *sb) {}
static inline bool erofs_ishare_fill_inode(struct inode *inode) { return false; }
static inline void erofs_ishare_free_inode(struct inode *inode) {}
+static inline struct inode *erofs_ishare_iget(struct inode *inode) { return inode; }
+static inline void erofs_ishare_iput(struct inode *realinode) {}
#endif // CONFIG_EROFS_FS_PAGE_CACHE_SHARE
long erofs_ioctl(struct file *filp, unsigned int cmd, unsigned long arg);
diff --git a/fs/erofs/ishare.c b/fs/erofs/ishare.c
index f386efb260da..da735d69f21f 100644
--- a/fs/erofs/ishare.c
+++ b/fs/erofs/ishare.c
@@ -239,3 +239,34 @@ const struct file_operations erofs_ishare_fops = {
.get_unmapped_area = thp_get_unmapped_area,
.splice_read = filemap_splice_read,
};
+
+/*
+ * erofs_ishare_iget - find the backing inode.
+ */
+struct inode *erofs_ishare_iget(struct inode *inode)
+{
+ struct erofs_inode *vi, *vi_dedup;
+ struct inode *realinode;
+
+ if (!erofs_is_ishare_inode(inode))
+ return igrab(inode);
+
+ vi_dedup = EROFS_I(inode);
+ spin_lock(&vi_dedup->lock);
+ /* fall back to all backing inodes */
+ DBG_BUGON(list_empty(&vi_dedup->backing_head));
+ list_for_each_entry(vi, &vi_dedup->backing_head, backing_link) {
+ realinode = igrab(&vi->vfs_inode);
+ if (realinode)
+ break;
+ }
+ spin_unlock(&vi_dedup->lock);
+
+ DBG_BUGON(!realinode);
+ return realinode;
+}
+
+void erofs_ishare_iput(struct inode *realinode)
+{
+ iput(realinode);
+}
--
2.22.0
^ permalink raw reply related [flat|nested] 20+ messages in thread
* [PATCH v9 09/10] erofs: support compressed inodes for page cache share
2025-11-17 13:25 [PATCH v9 00/10] erofs: inode page cache share feature Hongbo Li
` (7 preceding siblings ...)
2025-11-17 13:25 ` [PATCH v9 08/10] erofs: support unencoded inodes for page cache share Hongbo Li
@ 2025-11-17 13:25 ` Hongbo Li
2025-11-17 13:25 ` [PATCH v9 10/10] erofs: implement .fadvise " Hongbo Li
9 siblings, 0 replies; 20+ messages in thread
From: Hongbo Li @ 2025-11-17 13:25 UTC (permalink / raw)
To: hsiangkao, chao, brauner, djwong, amir73il, joannelkoong
Cc: lihongbo22, linux-fsdevel, linux-erofs, linux-kernel
From: Hongzhen Luo <hongzhen@linux.alibaba.com>
This patch adds page cache sharing functionality for compressed inodes.
Signed-off-by: Hongzhen Luo <hongzhen@linux.alibaba.com>
Signed-off-by: Hongbo Li <lihongbo22@huawei.com>
---
fs/erofs/zdata.c | 42 ++++++++++++++++++++++++++++++++----------
1 file changed, 32 insertions(+), 10 deletions(-)
diff --git a/fs/erofs/zdata.c b/fs/erofs/zdata.c
index bc80cfe482f7..f92891022670 100644
--- a/fs/erofs/zdata.c
+++ b/fs/erofs/zdata.c
@@ -493,7 +493,7 @@ enum z_erofs_pclustermode {
};
struct z_erofs_frontend {
- struct inode *const inode;
+ struct inode *inode;
struct erofs_map_blocks map;
struct z_erofs_bvec_iter biter;
@@ -1870,10 +1870,18 @@ static void z_erofs_pcluster_readmore(struct z_erofs_frontend *f,
static int z_erofs_read_folio(struct file *file, struct folio *folio)
{
- struct inode *const inode = folio->mapping->host;
- Z_EROFS_DEFINE_FRONTEND(f, inode, folio_pos(folio));
+ struct inode *const inode = folio->mapping->host, *realinode;
+ Z_EROFS_DEFINE_FRONTEND(f, NULL, folio_pos(folio));
int err;
+ if (erofs_is_ishare_inode(inode))
+ realinode = erofs_ishare_iget(inode);
+ else
+ realinode = inode;
+
+ if (!realinode)
+ return -EIO;
+ f.inode = realinode;
trace_erofs_read_folio(folio, false);
z_erofs_pcluster_readmore(&f, NULL, true);
err = z_erofs_scan_folio(&f, folio, false);
@@ -1883,23 +1891,34 @@ static int z_erofs_read_folio(struct file *file, struct folio *folio)
/* if some pclusters are ready, need submit them anyway */
err = z_erofs_runqueue(&f, 0) ?: err;
if (err && err != -EINTR)
- erofs_err(inode->i_sb, "read error %d @ %lu of nid %llu",
- err, folio->index, EROFS_I(inode)->nid);
+ erofs_err(realinode->i_sb, "read error %d @ %lu of nid %llu",
+ err, folio->index, EROFS_I(realinode)->nid);
erofs_put_metabuf(&f.map.buf);
erofs_release_pages(&f.pagepool);
+
+ if (erofs_is_ishare_inode(inode))
+ erofs_ishare_iput(realinode);
return err;
}
static void z_erofs_readahead(struct readahead_control *rac)
{
- struct inode *const inode = rac->mapping->host;
- Z_EROFS_DEFINE_FRONTEND(f, inode, readahead_pos(rac));
+ struct inode *const inode = rac->mapping->host, *realinode;
+ Z_EROFS_DEFINE_FRONTEND(f, NULL, readahead_pos(rac));
unsigned int nrpages = readahead_count(rac);
struct folio *head = NULL, *folio;
int err;
- trace_erofs_readahead(inode, readahead_index(rac), nrpages, false);
+ if (erofs_is_ishare_inode(inode))
+ realinode = erofs_ishare_iget(inode);
+ else
+ realinode = inode;
+
+ if (!realinode)
+ return;
+ f.inode = realinode;
+ trace_erofs_readahead(realinode, readahead_index(rac), nrpages, false);
z_erofs_pcluster_readmore(&f, rac, true);
while ((folio = readahead_folio(rac))) {
folio->private = head;
@@ -1913,8 +1932,8 @@ static void z_erofs_readahead(struct readahead_control *rac)
err = z_erofs_scan_folio(&f, folio, true);
if (err && err != -EINTR)
- erofs_err(inode->i_sb, "readahead error at folio %lu @ nid %llu",
- folio->index, EROFS_I(inode)->nid);
+ erofs_err(realinode->i_sb, "readahead error at folio %lu @ nid %llu",
+ folio->index, EROFS_I(realinode)->nid);
}
z_erofs_pcluster_readmore(&f, rac, false);
z_erofs_pcluster_end(&f);
@@ -1922,6 +1941,9 @@ static void z_erofs_readahead(struct readahead_control *rac)
(void)z_erofs_runqueue(&f, nrpages);
erofs_put_metabuf(&f.map.buf);
erofs_release_pages(&f.pagepool);
+
+ if (erofs_is_ishare_inode(inode))
+ erofs_ishare_iput(realinode);
}
const struct address_space_operations z_erofs_aops = {
--
2.22.0
^ permalink raw reply related [flat|nested] 20+ messages in thread
* [PATCH v9 10/10] erofs: implement .fadvise for page cache share
2025-11-17 13:25 [PATCH v9 00/10] erofs: inode page cache share feature Hongbo Li
` (8 preceding siblings ...)
2025-11-17 13:25 ` [PATCH v9 09/10] erofs: support compressed " Hongbo Li
@ 2025-11-17 13:25 ` Hongbo Li
9 siblings, 0 replies; 20+ messages in thread
From: Hongbo Li @ 2025-11-17 13:25 UTC (permalink / raw)
To: hsiangkao, chao, brauner, djwong, amir73il, joannelkoong
Cc: lihongbo22, linux-fsdevel, linux-erofs, linux-kernel
From: Hongzhen Luo <hongzhen@linux.alibaba.com>
This patch implements the .fadvise interface for page cache share.
Similar to overlayfs, it drops those clean, unused pages through
vfs_fadvise().
Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com>
Signed-off-by: Hongzhen Luo <hongzhen@linux.alibaba.com>
Signed-off-by: Hongbo Li <lihongbo22@huawei.com>
---
fs/erofs/ishare.c | 11 +++++++++++
1 file changed, 11 insertions(+)
diff --git a/fs/erofs/ishare.c b/fs/erofs/ishare.c
index da735d69f21f..d8bff0cdf702 100644
--- a/fs/erofs/ishare.c
+++ b/fs/erofs/ishare.c
@@ -230,6 +230,16 @@ static int erofs_ishare_mmap(struct file *file, struct vm_area_struct *vma)
return generic_file_readonly_mmap(file, vma);
}
+static int erofs_ishare_fadvise(struct file *file, loff_t offset,
+ loff_t len, int advice)
+{
+ struct file *realfile = file->private_data;
+
+ if (!realfile)
+ return -EINVAL;
+ return vfs_fadvise(realfile, offset, len, advice);
+}
+
const struct file_operations erofs_ishare_fops = {
.open = erofs_ishare_file_open,
.llseek = generic_file_llseek,
@@ -238,6 +248,7 @@ const struct file_operations erofs_ishare_fops = {
.release = erofs_ishare_file_release,
.get_unmapped_area = thp_get_unmapped_area,
.splice_read = filemap_splice_read,
+ .fadvise = erofs_ishare_fadvise,
};
/*
--
2.22.0
^ permalink raw reply related [flat|nested] 20+ messages in thread
* Re: [PATCH v9 01/10] iomap: stash iomap read ctx in the private field of iomap_iter
2025-11-17 13:25 ` [PATCH v9 01/10] iomap: stash iomap read ctx in the private field of iomap_iter Hongbo Li
@ 2025-11-17 17:08 ` Gao Xiang
2025-11-18 7:35 ` Gao Xiang
0 siblings, 1 reply; 20+ messages in thread
From: Gao Xiang @ 2025-11-17 17:08 UTC (permalink / raw)
To: brauner, djwong
Cc: linux-fsdevel, linux-erofs, linux-kernel, Chao Yu, Amir Goldstein,
Joanne Koong, Hongbo Li
Hi Darrick, Christian,
On 2025/11/17 21:25, Hongbo Li wrote:
> It's useful to get filesystem-specific information using the
> existing private field in the @iomap_iter passed to iomap_{begin,end}
> for advanced usage for iomap buffered reads, which is much like the
> current iomap DIO.
>
> For example, EROFS needs it to:
>
> - implement an efficient page cache sharing feature, since iomap
> needs to apply to anon inode page cache but we'd like to get the
> backing inode/fs instead, so filesystem-specific private data is
> needed to keep such information;
>
> - pass in both struct page * and void * for inline data to avoid
> kmap_to_page() usage (which is bogus).
>
> Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com>
> Signed-off-by: Hongbo Li <lihongbo22@huawei.com>
Could you help review this iomap change, since erofs uses iomap
and erofs page cache sharing needs this change, as I told
Joanne months ago.
Even without the page cache sharing feature, introducing
iomap_iter_ctx for .iomap_{begin,end}, like the current DIO
does, is still useful for erofs, as patch 2 mentioned.
Thanks,
Gao XIang
^ permalink raw reply [flat|nested] 20+ messages in thread
* Re: [PATCH v9 05/10] erofs: support user-defined fingerprint name
2025-11-17 13:25 ` [PATCH v9 05/10] erofs: support user-defined fingerprint name Hongbo Li
@ 2025-11-17 17:26 ` Gao Xiang
2025-11-18 2:16 ` Hongbo Li
0 siblings, 1 reply; 20+ messages in thread
From: Gao Xiang @ 2025-11-17 17:26 UTC (permalink / raw)
To: Hongbo Li, chao, brauner, djwong, amir73il, joannelkoong
Cc: linux-fsdevel, linux-erofs, linux-kernel
On 2025/11/17 21:25, Hongbo Li wrote:
> From: Hongzhen Luo <hongzhen@linux.alibaba.com>
>
> When creating the EROFS image, users can specify the fingerprint name.
> This is to prepare for the upcoming inode page cache share.
>
> Signed-off-by: Hongzhen Luo <hongzhen@linux.alibaba.com>
> Signed-off-by: Hongbo Li <lihongbo22@huawei.com>
> ---
> fs/erofs/Kconfig | 9 +++++++++
> fs/erofs/erofs_fs.h | 6 ++++--
> fs/erofs/internal.h | 2 ++
> fs/erofs/super.c | 5 +++--
> fs/erofs/xattr.c | 15 +++++++++++++++
> 5 files changed, 33 insertions(+), 4 deletions(-)
>
> diff --git a/fs/erofs/Kconfig b/fs/erofs/Kconfig
> index d81f3318417d..c88b6d0714a4 100644
> --- a/fs/erofs/Kconfig
> +++ b/fs/erofs/Kconfig
> @@ -194,3 +194,12 @@ config EROFS_FS_PCPU_KTHREAD_HIPRI
> at higher priority.
>
> If unsure, say N.
> +
> +config EROFS_FS_PAGE_CACHE_SHARE
> + bool "EROFS page cache share support (experimental)"
> + depends on EROFS_FS && EROFS_FS_XATTR && !EROFS_FS_ONDEMAND
> + help
> + This enables page cache sharing among inodes with identical
> + content fingerprints on the same device.
> +
> + If unsure, say N.
> diff --git a/fs/erofs/erofs_fs.h b/fs/erofs/erofs_fs.h
> index 3d5738f80072..9b9fe1abe0b9 100644
> --- a/fs/erofs/erofs_fs.h
> +++ b/fs/erofs/erofs_fs.h
> @@ -35,8 +35,9 @@
> #define EROFS_FEATURE_INCOMPAT_XATTR_PREFIXES 0x00000040
> #define EROFS_FEATURE_INCOMPAT_48BIT 0x00000080
> #define EROFS_FEATURE_INCOMPAT_METABOX 0x00000100
> +#define EROFS_FEATURE_INCOMPAT_ISHARE_KEY 0x00000200
It seems that you didn't address this part I
mentioned in the previous reply:
https://lore.kernel.org/r/a3b0bac9-d08f-44dc-8adb-7cc85cae7b13@linux.alibaba.com
> #define EROFS_ALL_FEATURE_INCOMPAT \
> - ((EROFS_FEATURE_INCOMPAT_METABOX << 1) - 1)
> + ((EROFS_FEATURE_INCOMPAT_ISHARE_KEY << 1) - 1)
>
> #define EROFS_SB_EXTSLOT_SIZE 16
>
> @@ -83,7 +84,8 @@ struct erofs_super_block {
> __le32 xattr_prefix_start; /* start of long xattr prefixes */
> __le64 packed_nid; /* nid of the special packed inode */
> __u8 xattr_filter_reserved; /* reserved for xattr name filter */
> - __u8 reserved[3];
> + __u8 ishare_xattr_prefix_id; /* indice the ishare key in prefix xattr */
/* indexes the ishare key in prefix xattres */ ?
> + __u8 reserved[2];
> __le32 build_time; /* seconds added to epoch for mkfs time */
> __le64 rootnid_8b; /* (48BIT on) nid of root directory */
> __le64 reserved2;
> diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h
> index 98fe652aea33..3033252211ba 100644
> --- a/fs/erofs/internal.h
> +++ b/fs/erofs/internal.h
> @@ -134,6 +134,7 @@ struct erofs_sb_info {
> u32 xattr_blkaddr;
> u32 xattr_prefix_start;
> u8 xattr_prefix_count;
> + u8 ishare_xattr_pfx; /* ishare prefix xattr index */
I think either giving a meaningful comment or just
get rid of the comment entirely.
> struct erofs_xattr_prefix_item *xattr_prefixes;
> unsigned int xattr_filter_reserved;
> #endif
> @@ -234,6 +235,7 @@ EROFS_FEATURE_FUNCS(dedupe, incompat, INCOMPAT_DEDUPE)
> EROFS_FEATURE_FUNCS(xattr_prefixes, incompat, INCOMPAT_XATTR_PREFIXES)
> EROFS_FEATURE_FUNCS(48bit, incompat, INCOMPAT_48BIT)
> EROFS_FEATURE_FUNCS(metabox, incompat, INCOMPAT_METABOX)
> +EROFS_FEATURE_FUNCS(ishare_key, incompat, INCOMPAT_ISHARE_KEY)
> EROFS_FEATURE_FUNCS(sb_chksum, compat, COMPAT_SB_CHKSUM)
> EROFS_FEATURE_FUNCS(xattr_filter, compat, COMPAT_XATTR_FILTER)
> EROFS_FEATURE_FUNCS(shared_ea_in_metabox, compat, COMPAT_SHARED_EA_IN_METABOX)
> diff --git a/fs/erofs/super.c b/fs/erofs/super.c
> index 0d88c04684b9..80f032cb2cc3 100644
> --- a/fs/erofs/super.c
> +++ b/fs/erofs/super.c
> @@ -298,6 +298,9 @@ static int erofs_read_superblock(struct super_block *sb)
> if (ret)
> goto out;
> }
> + if (erofs_sb_has_ishare_key(sbi))
> + sbi->ishare_xattr_pfx =
> + dsb->ishare_xattr_prefix_id & EROFS_XATTR_LONG_PREFIX_MASK;
>
> ret = -EINVAL;
> sbi->feature_incompat = le32_to_cpu(dsb->feature_incompat);
> @@ -339,7 +342,6 @@ static int erofs_read_superblock(struct super_block *sb)
> return -EFSCORRUPTED; /* self-loop detection */
> }
> sbi->inos = le64_to_cpu(dsb->inos);
> -
Unnecessary change here.
> sbi->epoch = (s64)le64_to_cpu(dsb->epoch);
> sbi->fixed_nsec = le32_to_cpu(dsb->fixed_nsec);
> super_set_uuid(sb, (void *)dsb->uuid, sizeof(dsb->uuid));
> @@ -737,7 +739,6 @@ static int erofs_fc_fill_super(struct super_block *sb, struct fs_context *fc)
> err = erofs_xattr_prefixes_init(sb);
> if (err)
> return err;
> -
Unnecessary change here.
> erofs_set_sysfs_name(sb);
> err = erofs_register_sysfs(sb);
> if (err)
> diff --git a/fs/erofs/xattr.c b/fs/erofs/xattr.c
> index 396536d9a862..6cb76313c14c 100644
> --- a/fs/erofs/xattr.c
> +++ b/fs/erofs/xattr.c
> @@ -519,6 +519,21 @@ int erofs_xattr_prefixes_init(struct super_block *sb)
> }
>
> erofs_put_metabuf(&buf);
> + if (!ret && erofs_sb_has_ishare_key(sbi)) {
> + struct erofs_xattr_long_prefix *new_pfx, *pfx =
> + pfs[sbi->ishare_xattr_pfx].prefix;
struct erofs_xattr_prefix_item *pf = pfs + sbi->ishare_xattr_pfx;
struct erofs_xattr_long_prefix *newpfx;
newpfx = krealloc(pf->prefix,
sizeof(*newpfx) + pf->infix_len + 1, GFP_KERNEL);
if (newpfx) {
newpfx->infix[pf->infix_len] = '\0';
pf->prefix = newpfx;
} else {
ret = -ENOMEM;
}
Thanks,
Gao Xiang
> +
> + new_pfx = krealloc(pfx,
> + sizeof(struct erofs_xattr_long_prefix) +
> + pfs[sbi->ishare_xattr_pfx].infix_len + 1,
> + GFP_KERNEL);
> + if (new_pfx) {
> + new_pfx->infix[pfs[sbi->ishare_xattr_pfx].infix_len] = '\0';
> + pfs[sbi->ishare_xattr_pfx].prefix = new_pfx;
> + } else {
> + ret = -ENOMEM;
> + }
> + }
> sbi->xattr_prefixes = pfs;
> if (ret)
> erofs_xattr_prefixes_cleanup(sb);
^ permalink raw reply [flat|nested] 20+ messages in thread
* Re: [PATCH v9 08/10] erofs: support unencoded inodes for page cache share
2025-11-17 13:25 ` [PATCH v9 08/10] erofs: support unencoded inodes for page cache share Hongbo Li
@ 2025-11-18 2:13 ` Hongbo Li
0 siblings, 0 replies; 20+ messages in thread
From: Hongbo Li @ 2025-11-18 2:13 UTC (permalink / raw)
To: hsiangkao, chao, brauner, djwong, amir73il, joannelkoong
Cc: linux-fsdevel, linux-erofs, linux-kernel
Hi,
On 2025/11/17 21:25, Hongbo Li wrote:
> This patch adds inode page cache sharing functionality for unencoded
> files.
>
> I conducted experiments in the container environment. Below is the
> memory usage for reading all files in two different minor versions
> of container images:
>
> +-------------------+------------------+-------------+---------------+
> | Image | Page Cache Share | Memory (MB) | Memory |
> | | | | Reduction (%) |
> +-------------------+------------------+-------------+---------------+
> | | No | 241 | - |
> | redis +------------------+-------------+---------------+
> | 7.2.4 & 7.2.5 | Yes | 163 | 33% |
> +-------------------+------------------+-------------+---------------+
> | | No | 872 | - |
> | postgres +------------------+-------------+---------------+
> | 16.1 & 16.2 | Yes | 630 | 28% |
> +-------------------+------------------+-------------+---------------+
> | | No | 2771 | - |
> | tensorflow +------------------+-------------+---------------+
> | 2.11.0 & 2.11.1 | Yes | 2340 | 16% |
> +-------------------+------------------+-------------+---------------+
> | | No | 926 | - |
> | mysql +------------------+-------------+---------------+
> | 8.0.11 & 8.0.12 | Yes | 735 | 21% |
> +-------------------+------------------+-------------+---------------+
> | | No | 390 | - |
> | nginx +------------------+-------------+---------------+
> | 7.2.4 & 7.2.5 | Yes | 219 | 44% |
> +-------------------+------------------+-------------+---------------+
> | tomcat | No | 924 | - |
> | 10.1.25 & 10.1.26 +------------------+-------------+---------------+
> | | Yes | 474 | 49% |
> +-------------------+------------------+-------------+---------------+
>
> Additionally, the table below shows the runtime memory usage of the
> container:
>
> +-------------------+------------------+-------------+---------------+
> | Image | Page Cache Share | Memory (MB) | Memory |
> | | | | Reduction (%) |
> +-------------------+------------------+-------------+---------------+
> | | No | 35 | - |
> | redis +------------------+-------------+---------------+
> | 7.2.4 & 7.2.5 | Yes | 28 | 20% |
> +-------------------+------------------+-------------+---------------+
> | | No | 149 | - |
> | postgres +------------------+-------------+---------------+
> | 16.1 & 16.2 | Yes | 95 | 37% |
> +-------------------+------------------+-------------+---------------+
> | | No | 1028 | - |
> | tensorflow +------------------+-------------+---------------+
> | 2.11.0 & 2.11.1 | Yes | 930 | 10% |
> +-------------------+------------------+-------------+---------------+
> | | No | 155 | - |
> | mysql +------------------+-------------+---------------+
> | 8.0.11 & 8.0.12 | Yes | 132 | 15% |
> +-------------------+------------------+-------------+---------------+
> | | No | 25 | - |
> | nginx +------------------+-------------+---------------+
> | 7.2.4 & 7.2.5 | Yes | 20 | 20% |
> +-------------------+------------------+-------------+---------------+
> | tomcat | No | 186 | - |
> | 10.1.25 & 10.1.26 +------------------+-------------+---------------+
> | | Yes | 98 | 48% |
> +-------------------+------------------+-------------+---------------+
>
> Co-developed-by: Hongzhen Luo <hongzhen@linux.alibaba.com>
> Signed-off-by: Hongzhen Luo <hongzhen@linux.alibaba.com>
> Signed-off-by: Hongbo Li <lihongbo22@huawei.com>
> ---
> fs/erofs/data.c | 30 +++++++++++++++++++++++-------
> fs/erofs/inode.c | 4 ++++
> fs/erofs/internal.h | 17 +++++++++++++++++
> fs/erofs/ishare.c | 31 +++++++++++++++++++++++++++++++
> 4 files changed, 75 insertions(+), 7 deletions(-)
>
> diff --git a/fs/erofs/data.c b/fs/erofs/data.c
> index 71e23d91123d..862df0c7ceb7 100644
> --- a/fs/erofs/data.c
> +++ b/fs/erofs/data.c
> @@ -269,6 +269,7 @@ void erofs_onlinefolio_end(struct folio *folio, int err, bool dirty)
> struct erofs_iomap_iter_ctx {
> struct page *page;
> void *base;
> + struct inode *realinode;
> };
>
> static int erofs_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
> @@ -276,14 +277,15 @@ static int erofs_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
> {
> 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 inode *realinode = ctx ? ctx->realinode : inode;
> + struct super_block *sb = realinode->i_sb;
> struct erofs_map_blocks map;
> struct erofs_map_dev mdev;
> int ret;
>
> map.m_la = offset;
> map.m_llen = length;
> - ret = erofs_map_blocks(inode, &map);
> + ret = erofs_map_blocks(realinode, &map);
> if (ret < 0)
> return ret;
>
> @@ -296,7 +298,7 @@ static int erofs_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
> return 0;
> }
>
> - if (!(map.m_flags & EROFS_MAP_META) || !erofs_inode_in_metabox(inode)) {
> + if (!(map.m_flags & EROFS_MAP_META) || !erofs_inode_in_metabox(realinode)) {
> mdev = (struct erofs_map_dev) {
> .m_deviceid = map.m_deviceid,
> .m_pa = map.m_pa,
> @@ -322,7 +324,7 @@ static int erofs_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
> void *ptr;
>
> ptr = erofs_read_metabuf(&buf, sb, map.m_pa,
> - erofs_inode_in_metabox(inode));
> + erofs_inode_in_metabox(realinode));
> if (IS_ERR(ptr))
> return PTR_ERR(ptr);
> iomap->inline_data = ptr;
> @@ -379,30 +381,42 @@ int erofs_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
> */
> static int erofs_read_folio(struct file *file, struct folio *folio)
> {
> + struct inode *inode = folio_inode(folio);
> struct iomap_read_folio_ctx read_ctx = {
> .ops = &iomap_bio_read_ops,
> .cur_folio = folio,
> };
> - struct erofs_iomap_iter_ctx iter_ctx = {};
> + struct erofs_iomap_iter_ctx iter_ctx = {
> + .realinode = erofs_ishare_iget(inode),
> + };
>
> + if (!iter_ctx.realinode)
> + return -EIO;
> trace_erofs_read_folio(folio, true);
>
> iomap_read_folio(&erofs_iomap_ops, &read_ctx, &iter_ctx);
> + erofs_ishare_iput(iter_ctx.realinode);
> return 0;
> }
>
> static void erofs_readahead(struct readahead_control *rac)
> {
> + struct inode *inode = rac->mapping->host;
> struct iomap_read_folio_ctx read_ctx = {
> .ops = &iomap_bio_read_ops,
> .rac = rac,
> };
> - struct erofs_iomap_iter_ctx iter_ctx = {};
> + struct erofs_iomap_iter_ctx iter_ctx = {
> + .realinode = erofs_ishare_iget(inode),
> + };
>
> + if (!iter_ctx.realinode)
> + return;
> trace_erofs_readahead(rac->mapping->host, readahead_index(rac),
> readahead_count(rac), true);
>
> iomap_readahead(&erofs_iomap_ops, &read_ctx, &iter_ctx);
> + erofs_ishare_iput(iter_ctx.realinode);
> }
>
> static sector_t erofs_bmap(struct address_space *mapping, sector_t block)
> @@ -423,7 +437,9 @@ static ssize_t erofs_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
> return dax_iomap_rw(iocb, to, &erofs_iomap_ops);
> #endif
> if ((iocb->ki_flags & IOCB_DIRECT) && inode->i_sb->s_bdev) {
> - struct erofs_iomap_iter_ctx iter_ctx = {};
> + struct erofs_iomap_iter_ctx iter_ctx = {
> + .realinode = inode,
> + };
>
> return iomap_dio_rw(iocb, to, &erofs_iomap_ops,
> NULL, 0, &iter_ctx, 0);
> diff --git a/fs/erofs/inode.c b/fs/erofs/inode.c
> index cb780c095d28..3be4614d1add 100644
> --- a/fs/erofs/inode.c
> +++ b/fs/erofs/inode.c
> @@ -215,6 +215,10 @@ static int erofs_fill_inode(struct inode *inode)
> case S_IFREG:
> inode->i_op = &erofs_generic_iops;
> inode->i_fop = &erofs_file_fops;
> +#ifdef CONFIG_EROFS_FS_PAGE_CACHE_SHARE
> + if (erofs_ishare_fill_inode(inode))
> + inode->i_fop = &erofs_ishare_fops;
> +#endif
> break;
> case S_IFDIR:
> inode->i_op = &erofs_dir_iops;
> diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h
> index 93ad34f2b488..37b536eebc3d 100644
> --- a/fs/erofs/internal.h
> +++ b/fs/erofs/internal.h
> @@ -197,6 +197,19 @@ static inline bool erofs_is_fscache_mode(struct super_block *sb)
> !erofs_is_fileio_mode(EROFS_SB(sb)) && !sb->s_bdev;
> }
>
> +#if defined(CONFIG_EROFS_FS_INODE_SHARE)
-#if defined(CONFIG_EROFS_FS_INODE_SHARE)
+#if defined(CONFIG_EROFS_FS_PAGE_CACHE_SHARE)
I forgot updating here, and will update in the next version.
Thanks,
Hongbo
> +static inline bool erofs_is_ishare_inode(struct inode *inode)
> +{
> + /* we have assumed FS_ONDEMAND is excluded with FS_INODE_SHARE feature */
> + return inode->i_sb->s_type == &erofs_anon_fs_type;
> +}
> +#else
> +static inline bool erofs_is_ishare_inode(struct inode *inode)
> +{
> + return false;
> +}
> +#endif
> +
> enum {
> EROFS_ZIP_CACHE_DISABLED,
> EROFS_ZIP_CACHE_READAHEAD,
> @@ -563,11 +576,15 @@ int erofs_ishare_init(struct super_block *sb);
> void erofs_ishare_exit(struct super_block *sb);
> bool erofs_ishare_fill_inode(struct inode *inode);
> void erofs_ishare_free_inode(struct inode *inode);
> +struct inode *erofs_ishare_iget(struct inode *inode);
> +void erofs_ishare_iput(struct inode *realinode);
> #else
> static inline int erofs_ishare_init(struct super_block *sb) { return 0; }
> static inline void erofs_ishare_exit(struct super_block *sb) {}
> static inline bool erofs_ishare_fill_inode(struct inode *inode) { return false; }
> static inline void erofs_ishare_free_inode(struct inode *inode) {}
> +static inline struct inode *erofs_ishare_iget(struct inode *inode) { return inode; }
> +static inline void erofs_ishare_iput(struct inode *realinode) {}
> #endif // CONFIG_EROFS_FS_PAGE_CACHE_SHARE
>
> long erofs_ioctl(struct file *filp, unsigned int cmd, unsigned long arg);
> diff --git a/fs/erofs/ishare.c b/fs/erofs/ishare.c
> index f386efb260da..da735d69f21f 100644
> --- a/fs/erofs/ishare.c
> +++ b/fs/erofs/ishare.c
> @@ -239,3 +239,34 @@ const struct file_operations erofs_ishare_fops = {
> .get_unmapped_area = thp_get_unmapped_area,
> .splice_read = filemap_splice_read,
> };
> +
> +/*
> + * erofs_ishare_iget - find the backing inode.
> + */
> +struct inode *erofs_ishare_iget(struct inode *inode)
> +{
> + struct erofs_inode *vi, *vi_dedup;
> + struct inode *realinode;
> +
> + if (!erofs_is_ishare_inode(inode))
> + return igrab(inode);
> +
> + vi_dedup = EROFS_I(inode);
> + spin_lock(&vi_dedup->lock);
> + /* fall back to all backing inodes */
> + DBG_BUGON(list_empty(&vi_dedup->backing_head));
> + list_for_each_entry(vi, &vi_dedup->backing_head, backing_link) {
> + realinode = igrab(&vi->vfs_inode);
> + if (realinode)
> + break;
> + }
> + spin_unlock(&vi_dedup->lock);
> +
> + DBG_BUGON(!realinode);
> + return realinode;
> +}
> +
> +void erofs_ishare_iput(struct inode *realinode)
> +{
> + iput(realinode);
> +}
^ permalink raw reply [flat|nested] 20+ messages in thread
* Re: [PATCH v9 05/10] erofs: support user-defined fingerprint name
2025-11-17 17:26 ` Gao Xiang
@ 2025-11-18 2:16 ` Hongbo Li
0 siblings, 0 replies; 20+ messages in thread
From: Hongbo Li @ 2025-11-18 2:16 UTC (permalink / raw)
To: Gao Xiang, chao, brauner, djwong, amir73il, joannelkoong
Cc: linux-fsdevel, linux-erofs, linux-kernel
Hi Xiang,
On 2025/11/18 1:26, Gao Xiang wrote:
>
>
> On 2025/11/17 21:25, Hongbo Li wrote:
>> From: Hongzhen Luo <hongzhen@linux.alibaba.com>
>>
>> When creating the EROFS image, users can specify the fingerprint name.
>> This is to prepare for the upcoming inode page cache share.
>>
>> Signed-off-by: Hongzhen Luo <hongzhen@linux.alibaba.com>
>> Signed-off-by: Hongbo Li <lihongbo22@huawei.com>
>> ---
>> fs/erofs/Kconfig | 9 +++++++++
>> fs/erofs/erofs_fs.h | 6 ++++--
>> fs/erofs/internal.h | 2 ++
>> fs/erofs/super.c | 5 +++--
>> fs/erofs/xattr.c | 15 +++++++++++++++
>> 5 files changed, 33 insertions(+), 4 deletions(-)
>>
>> diff --git a/fs/erofs/Kconfig b/fs/erofs/Kconfig
>> index d81f3318417d..c88b6d0714a4 100644
>> --- a/fs/erofs/Kconfig
>> +++ b/fs/erofs/Kconfig
>> @@ -194,3 +194,12 @@ config EROFS_FS_PCPU_KTHREAD_HIPRI
>> at higher priority.
>> If unsure, say N.
>> +
>> +config EROFS_FS_PAGE_CACHE_SHARE
>> + bool "EROFS page cache share support (experimental)"
>> + depends on EROFS_FS && EROFS_FS_XATTR && !EROFS_FS_ONDEMAND
>> + help
>> + This enables page cache sharing among inodes with identical
>> + content fingerprints on the same device.
>> +
>> + If unsure, say N.
>> diff --git a/fs/erofs/erofs_fs.h b/fs/erofs/erofs_fs.h
>> index 3d5738f80072..9b9fe1abe0b9 100644
>> --- a/fs/erofs/erofs_fs.h
>> +++ b/fs/erofs/erofs_fs.h
>> @@ -35,8 +35,9 @@
>> #define EROFS_FEATURE_INCOMPAT_XATTR_PREFIXES 0x00000040
>> #define EROFS_FEATURE_INCOMPAT_48BIT 0x00000080
>> #define EROFS_FEATURE_INCOMPAT_METABOX 0x00000100
>> +#define EROFS_FEATURE_INCOMPAT_ISHARE_KEY 0x00000200
>
> It seems that you didn't address this part I
> mentioned in the previous reply:
> https://lore.kernel.org/r/a3b0bac9-d08f-44dc-8adb-7cc85cae7b13@linux.alibaba.com
>
Thanks for pointing it out. I will update here in next version (include
the following issues).
diff --git a/fs/erofs/erofs_fs.h b/fs/erofs/erofs_fs.h
index 9b9fe1abe0b9..28955456d2e1 100644
--- a/fs/erofs/erofs_fs.h
+++ b/fs/erofs/erofs_fs.h
@@ -17,7 +17,7 @@
#define EROFS_FEATURE_COMPAT_XATTR_FILTER 0x00000004
#define EROFS_FEATURE_COMPAT_SHARED_EA_IN_METABOX 0x00000008
#define EROFS_FEATURE_COMPAT_PLAIN_XATTR_PFX 0x00000010
-
+#define EROFS_FEATURE_COMPAT_ISHARE_KEY 0x00000020
/*
* Any bits that aren't in EROFS_ALL_FEATURE_INCOMPAT should
@@ -35,9 +35,8 @@
#define EROFS_FEATURE_INCOMPAT_XATTR_PREFIXES 0x00000040
#define EROFS_FEATURE_INCOMPAT_48BIT 0x00000080
#define EROFS_FEATURE_INCOMPAT_METABOX 0x00000100
-#define EROFS_FEATURE_INCOMPAT_ISHARE_KEY 0x00000200
#define EROFS_ALL_FEATURE_INCOMPAT \
- ((EROFS_FEATURE_INCOMPAT_ISHARE_KEY << 1) - 1)
+ ((EROFS_FEATURE_INCOMPAT_METABOX << 1) - 1)
#define EROFS_SB_EXTSLOT_SIZE 16
diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h
index 37b536eebc3d..bb5dff36c9b8 100644
--- a/fs/erofs/internal.h
+++ b/fs/erofs/internal.h
@@ -248,11 +248,11 @@ EROFS_FEATURE_FUNCS(dedupe, incompat, INCOMPAT_DEDUPE)
EROFS_FEATURE_FUNCS(xattr_prefixes, incompat, INCOMPAT_XATTR_PREFIXES)
EROFS_FEATURE_FUNCS(48bit, incompat, INCOMPAT_48BIT)
EROFS_FEATURE_FUNCS(metabox, incompat, INCOMPAT_METABOX)
-EROFS_FEATURE_FUNCS(ishare_key, incompat, INCOMPAT_ISHARE_KEY)
EROFS_FEATURE_FUNCS(sb_chksum, compat, COMPAT_SB_CHKSUM)
EROFS_FEATURE_FUNCS(xattr_filter, compat, COMPAT_XATTR_FILTER)
EROFS_FEATURE_FUNCS(shared_ea_in_metabox, compat,
COMPAT_SHARED_EA_IN_METABOX)
EROFS_FEATURE_FUNCS(plain_xattr_pfx, compat, COMPAT_PLAIN_XATTR_PFX)
+EROFS_FEATURE_FUNCS(ishare_key, compat, COMPAT_ISHARE_KEY)
static inline u64 erofs_nid_to_ino64(struct erofs_sb_info *sbi,
erofs_nid_t nid)
{
Thanks,
Hongbo
>> #define EROFS_ALL_FEATURE_INCOMPAT \
>> - ((EROFS_FEATURE_INCOMPAT_METABOX << 1) - 1)
>> + ((EROFS_FEATURE_INCOMPAT_ISHARE_KEY << 1) - 1)
>> #define EROFS_SB_EXTSLOT_SIZE 16
>> @@ -83,7 +84,8 @@ struct erofs_super_block {
>> __le32 xattr_prefix_start; /* start of long xattr prefixes */
>> __le64 packed_nid; /* nid of the special packed inode */
>> __u8 xattr_filter_reserved; /* reserved for xattr name filter */
>> - __u8 reserved[3];
>> + __u8 ishare_xattr_prefix_id; /* indice the ishare key in
>> prefix xattr */
>
> /* indexes the ishare key in prefix xattres */ ?
>
>> + __u8 reserved[2];
>> __le32 build_time; /* seconds added to epoch for mkfs time */
>> __le64 rootnid_8b; /* (48BIT on) nid of root directory */
>> __le64 reserved2;
>> diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h
>> index 98fe652aea33..3033252211ba 100644
>> --- a/fs/erofs/internal.h
>> +++ b/fs/erofs/internal.h
>> @@ -134,6 +134,7 @@ struct erofs_sb_info {
>> u32 xattr_blkaddr;
>> u32 xattr_prefix_start;
>> u8 xattr_prefix_count;
>> + u8 ishare_xattr_pfx; /* ishare prefix xattr index */
>
> I think either giving a meaningful comment or just
> get rid of the comment entirely.
>
>> struct erofs_xattr_prefix_item *xattr_prefixes;
>> unsigned int xattr_filter_reserved;
>> #endif
>> @@ -234,6 +235,7 @@ EROFS_FEATURE_FUNCS(dedupe, incompat,
>> INCOMPAT_DEDUPE)
>> EROFS_FEATURE_FUNCS(xattr_prefixes, incompat, INCOMPAT_XATTR_PREFIXES)
>> EROFS_FEATURE_FUNCS(48bit, incompat, INCOMPAT_48BIT)
>> EROFS_FEATURE_FUNCS(metabox, incompat, INCOMPAT_METABOX)
>> +EROFS_FEATURE_FUNCS(ishare_key, incompat, INCOMPAT_ISHARE_KEY)
>> EROFS_FEATURE_FUNCS(sb_chksum, compat, COMPAT_SB_CHKSUM)
>> EROFS_FEATURE_FUNCS(xattr_filter, compat, COMPAT_XATTR_FILTER)
>> EROFS_FEATURE_FUNCS(shared_ea_in_metabox, compat,
>> COMPAT_SHARED_EA_IN_METABOX)
>> diff --git a/fs/erofs/super.c b/fs/erofs/super.c
>> index 0d88c04684b9..80f032cb2cc3 100644
>> --- a/fs/erofs/super.c
>> +++ b/fs/erofs/super.c
>> @@ -298,6 +298,9 @@ static int erofs_read_superblock(struct
>> super_block *sb)
>> if (ret)
>> goto out;
>> }
>> + if (erofs_sb_has_ishare_key(sbi))
>> + sbi->ishare_xattr_pfx =
>> + dsb->ishare_xattr_prefix_id & EROFS_XATTR_LONG_PREFIX_MASK;
>> ret = -EINVAL;
>> sbi->feature_incompat = le32_to_cpu(dsb->feature_incompat);
>> @@ -339,7 +342,6 @@ static int erofs_read_superblock(struct
>> super_block *sb)
>> return -EFSCORRUPTED; /* self-loop detection */
>> }
>> sbi->inos = le64_to_cpu(dsb->inos);
>> -
>
> Unnecessary change here.
>
>> sbi->epoch = (s64)le64_to_cpu(dsb->epoch);
>> sbi->fixed_nsec = le32_to_cpu(dsb->fixed_nsec);
>> super_set_uuid(sb, (void *)dsb->uuid, sizeof(dsb->uuid));
>> @@ -737,7 +739,6 @@ static int erofs_fc_fill_super(struct super_block
>> *sb, struct fs_context *fc)
>> err = erofs_xattr_prefixes_init(sb);
>> if (err)
>> return err;
>> -
>
> Unnecessary change here.
>
>> erofs_set_sysfs_name(sb);
>> err = erofs_register_sysfs(sb);
>> if (err)
>> diff --git a/fs/erofs/xattr.c b/fs/erofs/xattr.c
>> index 396536d9a862..6cb76313c14c 100644
>> --- a/fs/erofs/xattr.c
>> +++ b/fs/erofs/xattr.c
>> @@ -519,6 +519,21 @@ int erofs_xattr_prefixes_init(struct super_block
>> *sb)
>> }
>> erofs_put_metabuf(&buf);
>> + if (!ret && erofs_sb_has_ishare_key(sbi)) {
>> + struct erofs_xattr_long_prefix *new_pfx, *pfx =
>> + pfs[sbi->ishare_xattr_pfx].prefix;
>
> struct erofs_xattr_prefix_item *pf = pfs + sbi->ishare_xattr_pfx;
> struct erofs_xattr_long_prefix *newpfx;
>
> newpfx = krealloc(pf->prefix,
> sizeof(*newpfx) + pf->infix_len + 1, GFP_KERNEL);
> if (newpfx) {
> newpfx->infix[pf->infix_len] = '\0';
> pf->prefix = newpfx;
> } else {
> ret = -ENOMEM;
> }
>
> Thanks,
> Gao Xiang
>
>> +
>> + new_pfx = krealloc(pfx,
>> + sizeof(struct erofs_xattr_long_prefix) +
>> + pfs[sbi->ishare_xattr_pfx].infix_len + 1,
>> + GFP_KERNEL);
>> + if (new_pfx) {
>> + new_pfx->infix[pfs[sbi->ishare_xattr_pfx].infix_len] = '\0';
>> + pfs[sbi->ishare_xattr_pfx].prefix = new_pfx;
>> + } else {
>> + ret = -ENOMEM;
>> + }
>> + }
>> sbi->xattr_prefixes = pfs;
>> if (ret)
>> erofs_xattr_prefixes_cleanup(sb);
>
^ permalink raw reply related [flat|nested] 20+ messages in thread
* Re: [PATCH v9 01/10] iomap: stash iomap read ctx in the private field of iomap_iter
2025-11-17 17:08 ` Gao Xiang
@ 2025-11-18 7:35 ` Gao Xiang
2025-11-19 5:49 ` Christoph Hellwig
0 siblings, 1 reply; 20+ messages in thread
From: Gao Xiang @ 2025-11-18 7:35 UTC (permalink / raw)
To: brauner, djwong, Christoph Hellwig
Cc: linux-fsdevel, linux-erofs, linux-kernel, Chao Yu, Amir Goldstein,
Joanne Koong, Hongbo Li
(... try to add Christoph..)
On 2025/11/18 01:08, Gao Xiang wrote:
> Hi Darrick, Christian,
>
> On 2025/11/17 21:25, Hongbo Li wrote:
>> It's useful to get filesystem-specific information using the
>> existing private field in the @iomap_iter passed to iomap_{begin,end}
>> for advanced usage for iomap buffered reads, which is much like the
>> current iomap DIO.
>>
>> For example, EROFS needs it to:
>>
>> - implement an efficient page cache sharing feature, since iomap
>> needs to apply to anon inode page cache but we'd like to get the
>> backing inode/fs instead, so filesystem-specific private data is
>> needed to keep such information;
>>
>> - pass in both struct page * and void * for inline data to avoid
>> kmap_to_page() usage (which is bogus).
>>
>> Reviewed-by: Gao Xiang <hsiangkao@linux.alibaba.com>
>> Signed-off-by: Hongbo Li <lihongbo22@huawei.com>
>
> Could you help review this iomap change, since erofs uses iomap
> and erofs page cache sharing needs this change, as I told
> Joanne months ago.
>
> Even without the page cache sharing feature, introducing
> iomap_iter_ctx for .iomap_{begin,end}, like the current DIO
> does, is still useful for erofs, as patch 2 mentioned.
I know it could be somewhat too late to introduce the entire
feature for 6.19, but could we consider the first two patches
(patch 1 and 2) if possible? because:
- patch 1 just adds a way to specify iter->private for buffered
read since there was no way to pass on-stack fs-specific
contexts from .iomap_begin() to .iomap_end() for iomap
buffered read.
Actually patch 1 doesn't introduce any new logic or behavior
to iomap itself, just add a way to specify iter->private, I
think it does no harm to the iomap stability.
- patch 2 tries to avoid kmap_to_page() usage since previously
there is no way to pass both `void *` and `struct page *`
from .iomap_begin() to .iomap_end() because inline data
handling needs both.
Actually people would like to get rid of kmap_to_page(), for
example:
https://lore.kernel.org/r/Y5u+oOLkJs6jehik@iweiny-desk3
So I wonder if patch 1 and 2 can be considered as an
individual improvement for 6.19.
- Currently the page cache sharing series is coupled with iomap,
but the main change is still in erofs itself. If the first
two patches can be applied in advance, that would make the
remaining part through erofs tree without treewide conflict
like this.
Just my two cents.
Thanks,
Gao Xiang
^ permalink raw reply [flat|nested] 20+ messages in thread
* Re: [PATCH v9 01/10] iomap: stash iomap read ctx in the private field of iomap_iter
2025-11-18 7:35 ` Gao Xiang
@ 2025-11-19 5:49 ` Christoph Hellwig
2025-11-19 6:17 ` Gao Xiang
0 siblings, 1 reply; 20+ messages in thread
From: Christoph Hellwig @ 2025-11-19 5:49 UTC (permalink / raw)
To: Gao Xiang
Cc: brauner, djwong, Christoph Hellwig, linux-fsdevel, linux-erofs,
linux-kernel, Chao Yu, Amir Goldstein, Joanne Koong, Hongbo Li
On Tue, Nov 18, 2025 at 03:35:45PM +0800, Gao Xiang wrote:
> (... try to add Christoph..)
What are you asking me for?
^ permalink raw reply [flat|nested] 20+ messages in thread
* Re: [PATCH v9 01/10] iomap: stash iomap read ctx in the private field of iomap_iter
2025-11-19 5:49 ` Christoph Hellwig
@ 2025-11-19 6:17 ` Gao Xiang
2025-11-19 9:12 ` Christoph Hellwig
0 siblings, 1 reply; 20+ messages in thread
From: Gao Xiang @ 2025-11-19 6:17 UTC (permalink / raw)
To: Christoph Hellwig
Cc: brauner, djwong, linux-fsdevel, linux-erofs, linux-kernel,
Chao Yu, Amir Goldstein, Joanne Koong, Hongbo Li
Hi Christoph,
On 2025/11/19 13:49, Christoph Hellwig wrote:
> On Tue, Nov 18, 2025 at 03:35:45PM +0800, Gao Xiang wrote:
>> (... try to add Christoph..)
>
> What are you asking me for?
Sorry about the confusion.
Hongbo didn't Cc you on this thread (I think he just added
recipients according to MAINTAINERS), but I know you played
a key role in iomap development, so I think you should be
in the loop about the iomap change too.
Could you give some comments (maybe review) on this patch
if possible? My own opinion is that if the first two
patches can be applied in the next cycle (6.19) (I understand
it will be too late for the whole feature into 6.19) , it
would be very helpful to us so at least the vfs iomap branch
won't be coupled anymore if the first two patch can be landed
in advance.
Thanks,
Gao Xiang
^ permalink raw reply [flat|nested] 20+ messages in thread
* Re: [PATCH v9 01/10] iomap: stash iomap read ctx in the private field of iomap_iter
2025-11-19 6:17 ` Gao Xiang
@ 2025-11-19 9:12 ` Christoph Hellwig
2025-11-19 9:28 ` Gao Xiang
0 siblings, 1 reply; 20+ messages in thread
From: Christoph Hellwig @ 2025-11-19 9:12 UTC (permalink / raw)
To: Gao Xiang
Cc: Christoph Hellwig, brauner, djwong, linux-fsdevel, linux-erofs,
linux-kernel, Chao Yu, Amir Goldstein, Joanne Koong, Hongbo Li
On Wed, Nov 19, 2025 at 02:17:07PM +0800, Gao Xiang wrote:
> Hongbo didn't Cc you on this thread (I think he just added
> recipients according to MAINTAINERS), but I know you played
> a key role in iomap development, so I think you should be
> in the loop about the iomap change too.
>
> Could you give some comments (maybe review) on this patch
> if possible? My own opinion is that if the first two
> patches can be applied in the next cycle (6.19) (I understand
> it will be too late for the whole feature into 6.19) , it
> would be very helpful to us so at least the vfs iomap branch
> won't be coupled anymore if the first two patch can be landed
> in advance.
The patch itself looks fine. But as Darrick said we really need
to get our house in order for the iomap branch so that it actually
works this close to the merge window.
^ permalink raw reply [flat|nested] 20+ messages in thread
* Re: [PATCH v9 01/10] iomap: stash iomap read ctx in the private field of iomap_iter
2025-11-19 9:12 ` Christoph Hellwig
@ 2025-11-19 9:28 ` Gao Xiang
0 siblings, 0 replies; 20+ messages in thread
From: Gao Xiang @ 2025-11-19 9:28 UTC (permalink / raw)
To: Christoph Hellwig
Cc: brauner, djwong, linux-fsdevel, linux-erofs, linux-kernel,
Chao Yu, Amir Goldstein, Joanne Koong, Hongbo Li
On 2025/11/19 17:12, Christoph Hellwig wrote:
> On Wed, Nov 19, 2025 at 02:17:07PM +0800, Gao Xiang wrote:
>> Hongbo didn't Cc you on this thread (I think he just added
>> recipients according to MAINTAINERS), but I know you played
>> a key role in iomap development, so I think you should be
>> in the loop about the iomap change too.
>>
>> Could you give some comments (maybe review) on this patch
>> if possible? My own opinion is that if the first two
>> patches can be applied in the next cycle (6.19) (I understand
>> it will be too late for the whole feature into 6.19) , it
>> would be very helpful to us so at least the vfs iomap branch
>> won't be coupled anymore if the first two patch can be landed
>> in advance.
>
> The patch itself looks fine. But as Darrick said we really need
> to get our house in order for the iomap branch so that it actually
> works this close to the merge window.
Sigh.. I'm sorry to hear about that.
Anyway, personally I think patch 1 makes no change to iomap logic
(so I think it definitely does no harm to iomap stability), but
opens a chance for iomap users to control iter->private and pass
fs-specific contexts from iomap_begin to end (and patch 2 uses
this to get rid of kmap_to_page()). So honestly I'm eager to get
patches 1 and 2 merged.
However, it's really up to the iomap maintainers. Yet, if delayed
to the next development cycle, it might still need to resolve
cross-branch conflicts, and it could still causes some churn,
anyway...
Thanks,
Gao Xiang
^ permalink raw reply [flat|nested] 20+ messages in thread
end of thread, other threads:[~2025-11-19 9:28 UTC | newest]
Thread overview: 20+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2025-11-17 13:25 [PATCH v9 00/10] erofs: inode page cache share feature Hongbo Li
2025-11-17 13:25 ` [PATCH v9 01/10] iomap: stash iomap read ctx in the private field of iomap_iter Hongbo Li
2025-11-17 17:08 ` Gao Xiang
2025-11-18 7:35 ` Gao Xiang
2025-11-19 5:49 ` Christoph Hellwig
2025-11-19 6:17 ` Gao Xiang
2025-11-19 9:12 ` Christoph Hellwig
2025-11-19 9:28 ` Gao Xiang
2025-11-17 13:25 ` [PATCH v9 02/10] erofs: hold read context in iomap_iter if needed Hongbo Li
2025-11-17 13:25 ` [PATCH v9 03/10] fs: Export alloc_empty_backing_file Hongbo Li
2025-11-17 13:25 ` [PATCH v9 04/10] erofs: move `struct erofs_anon_fs_type` to super.c Hongbo Li
2025-11-17 13:25 ` [PATCH v9 05/10] erofs: support user-defined fingerprint name Hongbo Li
2025-11-17 17:26 ` Gao Xiang
2025-11-18 2:16 ` Hongbo Li
2025-11-17 13:25 ` [PATCH v9 06/10] erofs: support domain-specific page cache share Hongbo Li
2025-11-17 13:25 ` [PATCH v9 07/10] erofs: introduce the page cache share feature Hongbo Li
2025-11-17 13:25 ` [PATCH v9 08/10] erofs: support unencoded inodes for page cache share Hongbo Li
2025-11-18 2:13 ` Hongbo Li
2025-11-17 13:25 ` [PATCH v9 09/10] erofs: support compressed " Hongbo Li
2025-11-17 13:25 ` [PATCH v9 10/10] erofs: implement .fadvise " Hongbo Li
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