On 2025/11/14 17:55, Hongbo Li wrote:
From: Hongzhen Luo <[email protected]>
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 <[email protected]>
Signed-off-by: Hongbo Li <[email protected]>
---
fs/erofs/Kconfig | 9 +++++++++
fs/erofs/erofs_fs.h | 6 ++++--
fs/erofs/internal.h | 6 ++++++
fs/erofs/super.c | 5 ++++-
fs/erofs/xattr.c | 26 ++++++++++++++++++++++++++
fs/erofs/xattr.h | 6 ++++++
6 files changed, 55 insertions(+), 3 deletions(-)
diff --git a/fs/erofs/Kconfig b/fs/erofs/Kconfig
index d81f3318417d..1b5c0cd99203 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_INODE_SHARE
+ bool "EROFS inode page cache share support (experimental)"
+ depends on EROFS_FS && EROFS_FS_XATTR && !EROFS_FS_ONDEMAND
+ help
+ This permits EROFS to share page cache for files with same
+ fingerprints.
I tend to use "EROFS_FS_PAGE_CACHE_SHARE" since it's closer to
user impact definition (inode sharing is ambiguious), but we
could leave "ishare.c" since it's closer to the implementation
details.
And how about:
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.
+
+ If unsure, say N.
\ No newline at end of file
"\ No newline at end of file" should be fixed.
diff --git a/fs/erofs/erofs_fs.h b/fs/erofs/erofs_fs.h
index 3d5738f80072..104518cd161d 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
I do think it should be a compatible feature since images can be
mounted in the old kernels without any issue, and it should be
renamed as
EROFS_FEATURE_COMPAT_ISHARE_XATTRS
#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_key_start; /* start of ishare key */
ishare_xattr_prefix_id; ?
+ __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 e80b35db18e4..3ebbb7c5d085 100644
--- a/fs/erofs/internal.h
+++ b/fs/erofs/internal.h
@@ -167,6 +167,11 @@ struct erofs_sb_info {
struct erofs_domain *domain;
char *fsid;
char *domain_id;
+
+ /* inode page cache share support */
+ u8 ishare_key_start;
u8 ishare_xattr_pfx;
+ u8 ishare_key_idx;
why need this, considering we could just use
sbi->xattr_prefixes[sbi->ishare_xattr_pfx]
to get this.
+ char *ishare_key;
};
#define EROFS_SB(sb) ((struct erofs_sb_info *)(sb)->s_fs_info)
@@ -236,6 +241,7 @@ 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..3561473cb789 100644
--- a/fs/erofs/super.c
+++ b/fs/erofs/super.c
@@ -339,7 +339,7 @@ static int erofs_read_superblock(struct
super_block *sb)
return -EFSCORRUPTED; /* self-loop detection */
}
sbi->inos = le64_to_cpu(dsb->inos);
-
+ sbi->ishare_key_start = dsb->ishare_key_start;
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));
@@ -738,6 +738,9 @@ static int erofs_fc_fill_super(struct super_block
*sb, struct fs_context *fc)
if (err)
return err;
+ err = erofs_xattr_set_ishare_key(sb);
I don't think it's necessary to duplicate the copy, just use
"sbi->xattr_prefixes[sbi->ishare_xattr_pfx]" directly.
