[RFC PATCH v6 2/7] erofs: support user-defined fingerprint name
Hongbo Li
lihongbo22 at huawei.com
Sat Mar 22 12:12:45 AEDT 2025
On 2025/3/1 22:49, Hongzhen Luo wrote:
> 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 at linux.alibaba.com>
> ---
> fs/erofs/Kconfig | 10 +++++++++
> fs/erofs/erofs_fs.h | 9 ++++++---
> fs/erofs/internal.h | 6 ++++++
> fs/erofs/super.c | 4 ++++
> fs/erofs/xattr.c | 49 +++++++++++++++++++++++++++++++++++++++++++++
> fs/erofs/xattr.h | 6 ++++++
> 6 files changed, 81 insertions(+), 3 deletions(-)
>
> diff --git a/fs/erofs/Kconfig b/fs/erofs/Kconfig
> index 6ea60661fa55..d2416d35035a 100644
> --- a/fs/erofs/Kconfig
> +++ b/fs/erofs/Kconfig
> @@ -178,3 +178,13 @@ 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"
> + depends on EROFS_FS && EROFS_FS_XATTR
> + default n
> + help
> + This permits EROFS to share page cache for files with same
> + fingerprints.
> +
> + If unsure, say N.
> diff --git a/fs/erofs/erofs_fs.h b/fs/erofs/erofs_fs.h
> index 199395ed1c1f..261bd9bd47c4 100644
> --- a/fs/erofs/erofs_fs.h
> +++ b/fs/erofs/erofs_fs.h
> @@ -30,6 +30,7 @@
> #define EROFS_FEATURE_INCOMPAT_FRAGMENTS 0x00000020
> #define EROFS_FEATURE_INCOMPAT_DEDUPE 0x00000020
> #define EROFS_FEATURE_INCOMPAT_XATTR_PREFIXES 0x00000040
> +#define EROFS_FEATURE_INCOMPAT_ISHARE_KEY 0x00000080
> #define EROFS_ALL_FEATURE_INCOMPAT \
> (EROFS_FEATURE_INCOMPAT_ZERO_PADDING | \
> EROFS_FEATURE_INCOMPAT_COMPR_CFGS | \
> @@ -40,7 +41,8 @@
> EROFS_FEATURE_INCOMPAT_ZTAILPACKING | \
> EROFS_FEATURE_INCOMPAT_FRAGMENTS | \
> EROFS_FEATURE_INCOMPAT_DEDUPE | \
> - EROFS_FEATURE_INCOMPAT_XATTR_PREFIXES)
> + EROFS_FEATURE_INCOMPAT_XATTR_PREFIXES | \
> + EROFS_FEATURE_INCOMPAT_ISHARE_KEY)
>
> #define EROFS_SB_EXTSLOT_SIZE 16
>
> @@ -84,8 +86,9 @@ 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 reserved2[23];
> -};
> + __le32 ishare_key_start; /* start of ishare key */
> + __u8 reserved2[19];
> +} __packed;
>
> /*
> * EROFS inode datalayout (i_format in on-disk inode):
> diff --git a/fs/erofs/internal.h b/fs/erofs/internal.h
> index 47004eb89838..21bf9b694048 100644
> --- a/fs/erofs/internal.h
> +++ b/fs/erofs/internal.h
> @@ -166,6 +166,11 @@ struct erofs_sb_info {
> struct erofs_domain *domain;
> char *fsid;
> char *domain_id;
> +
> + /* inode page cache share support */
> + u32 ishare_key_start;
> + int ishare_key_idx;
> + char *ishare_key;
> };
>
> #define EROFS_SB(sb) ((struct erofs_sb_info *)(sb)->s_fs_info)
> @@ -233,6 +238,7 @@ EROFS_FEATURE_FUNCS(ztailpacking, incompat, INCOMPAT_ZTAILPACKING)
> EROFS_FEATURE_FUNCS(fragments, incompat, INCOMPAT_FRAGMENTS)
> EROFS_FEATURE_FUNCS(dedupe, incompat, INCOMPAT_DEDUPE)
> EROFS_FEATURE_FUNCS(xattr_prefixes, incompat, INCOMPAT_XATTR_PREFIXES)
> +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)
>
> diff --git a/fs/erofs/super.c b/fs/erofs/super.c
> index eb052a770088..6af02cc8b8c6 100644
> --- a/fs/erofs/super.c
> +++ b/fs/erofs/super.c
> @@ -313,6 +313,8 @@ static int erofs_read_superblock(struct super_block *sb)
> sbi->packed_nid = le64_to_cpu(dsb->packed_nid);
> sbi->inos = le64_to_cpu(dsb->inos);
>
> + sbi->ishare_key_start = le32_to_cpu(dsb->ishare_key_start);
> +
> sbi->build_time = le64_to_cpu(dsb->build_time);
> sbi->build_time_nsec = le32_to_cpu(dsb->build_time_nsec);
>
> @@ -676,6 +678,8 @@ static int erofs_fc_fill_super(struct super_block *sb, struct fs_context *fc)
> if (err)
> return err;
>
> + erofs_xattr_set_ishare_key(sb);
> +
> 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 7940241d9355..30a64ac3239a 100644
> --- a/fs/erofs/xattr.c
> +++ b/fs/erofs/xattr.c
> @@ -549,3 +549,52 @@ struct posix_acl *erofs_get_acl(struct inode *inode, int type, bool rcu)
> return acl;
> }
> #endif
> +
> +#ifdef CONFIG_EROFS_FS_INODE_SHARE
> +void erofs_xattr_set_ishare_key(struct super_block *sb)
> +{
> + struct erofs_sb_info *sbi = EROFS_SB(sb);
> + struct erofs_buf buf = __EROFS_BUF_INITIALIZER;
> + struct xattr_handler const *handler;
> + erofs_off_t pos;
> + char *key;
> + int len, i;
> + void *ptr;
> +
> + if (!erofs_sb_has_fragments(sbi) || !erofs_sb_has_ishare_key(sbi) ||
> + !sbi->packed_inode)
> + return;
> +
> + buf.mapping = sbi->packed_inode->i_mapping;
> + pos = sbi->ishare_key_start << 2;
> + ptr = erofs_read_metadata(sb, &buf, &pos, &len);
> +
> + if (IS_ERR(ptr)) {
> + erofs_put_metabuf(&buf);
> + return;
> + }
> +
> + for (i = 0; ARRAY_SIZE(erofs_xattr_handlers); i++) {
ARRAY_SIZE will get the length of array erofs_xattr_handlers, here you
must forget it. So here it should be i <
ARRAY_SIZE(erofs_xattr_handlers) - 1. :)
> + handler = erofs_xattr_handlers[i];
> + if (!handler)
> + break;
> + if (!memcmp(handler->prefix, ptr, strlen(handler->prefix)))
> + break;
> + }
> +
> + if (!handler)
> + return;
This exception branch lacks a call to erofs_put_metabuf(&buf).
> +
> + len -= strlen(handler->prefix);
> + key = kzalloc(len + 1, GFP_KERNEL);
> + if (!key) {
> + erofs_put_metabuf(&buf);
> + return;
> + }
> +
> + memcpy(key, ptr + strlen(handler->prefix), len);
> + sbi->ishare_key = key;
> + sbi->ishare_key_idx = handler->flags;
> + erofs_put_metabuf(&buf);
> +}
> +#endif
> diff --git a/fs/erofs/xattr.h b/fs/erofs/xattr.h
> index b246cd0e135e..24a243165417 100644
> --- a/fs/erofs/xattr.h
> +++ b/fs/erofs/xattr.h
> @@ -70,4 +70,10 @@ struct posix_acl *erofs_get_acl(struct inode *inode, int type, bool rcu);
> #define erofs_get_acl (NULL)
> #endif
>
> +#ifdef CONFIG_EROFS_FS_INODE_SHARE
> +void erofs_xattr_set_ishare_key(struct super_block *sb);
> +#else
> +static inline void erofs_xattr_set_ishare_key(struct super_block *sb) {}
> +#endif
> +
> #endif
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