From 9591c3a34f7722bd77f42c98d76fd5a5bad465f0 Mon Sep 17 00:00:00 2001 From: Amir Goldstein Date: Mon, 22 Mar 2021 19:39:43 +0200 Subject: [PATCH] fs: introduce a wrapper uuid_to_fsid() Some filesystem's use a digest of their uuid for f_fsid. Create a simple wrapper for this open coded folding. Filesystems that have a non null uuid but use the block device number for f_fsid may also consider using this helper. [JK: Added missing asm/byteorder.h include] Link: https://lore.kernel.org/r/20210322173944.449469-2-amir73il@gmail.com Acked-by: Damien Le Moal Reviewed-by: Christian Brauner Signed-off-by: Amir Goldstein Signed-off-by: Jan Kara --- fs/ext2/super.c | 5 +---- fs/ext4/super.c | 5 +---- fs/zonefs/super.c | 5 +---- include/linux/statfs.h | 8 ++++++++ 4 files changed, 11 insertions(+), 12 deletions(-) diff --git a/fs/ext2/super.c b/fs/ext2/super.c index 6c47532..0d67945 100644 --- a/fs/ext2/super.c +++ b/fs/ext2/super.c @@ -1399,7 +1399,6 @@ static int ext2_statfs (struct dentry * dentry, struct kstatfs * buf) struct super_block *sb = dentry->d_sb; struct ext2_sb_info *sbi = EXT2_SB(sb); struct ext2_super_block *es = sbi->s_es; - u64 fsid; spin_lock(&sbi->s_lock); @@ -1453,9 +1452,7 @@ static int ext2_statfs (struct dentry * dentry, struct kstatfs * buf) buf->f_ffree = ext2_count_free_inodes(sb); es->s_free_inodes_count = cpu_to_le32(buf->f_ffree); buf->f_namelen = EXT2_NAME_LEN; - fsid = le64_to_cpup((void *)es->s_uuid) ^ - le64_to_cpup((void *)es->s_uuid + sizeof(u64)); - buf->f_fsid = u64_to_fsid(fsid); + buf->f_fsid = uuid_to_fsid(es->s_uuid); spin_unlock(&sbi->s_lock); return 0; } diff --git a/fs/ext4/super.c b/fs/ext4/super.c index ad34a37..3581c1c 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -6148,7 +6148,6 @@ static int ext4_statfs(struct dentry *dentry, struct kstatfs *buf) struct ext4_sb_info *sbi = EXT4_SB(sb); struct ext4_super_block *es = sbi->s_es; ext4_fsblk_t overhead = 0, resv_blocks; - u64 fsid; s64 bfree; resv_blocks = EXT4_C2B(sbi, atomic64_read(&sbi->s_resv_clusters)); @@ -6169,9 +6168,7 @@ static int ext4_statfs(struct dentry *dentry, struct kstatfs *buf) buf->f_files = le32_to_cpu(es->s_inodes_count); buf->f_ffree = percpu_counter_sum_positive(&sbi->s_freeinodes_counter); buf->f_namelen = EXT4_NAME_LEN; - fsid = le64_to_cpup((void *)es->s_uuid) ^ - le64_to_cpup((void *)es->s_uuid + sizeof(u64)); - buf->f_fsid = u64_to_fsid(fsid); + buf->f_fsid = uuid_to_fsid(es->s_uuid); #ifdef CONFIG_QUOTA if (ext4_test_inode_flag(dentry->d_inode, EXT4_INODE_PROJINHERIT) && diff --git a/fs/zonefs/super.c b/fs/zonefs/super.c index 0fe76f3..e098103 100644 --- a/fs/zonefs/super.c +++ b/fs/zonefs/super.c @@ -1104,7 +1104,6 @@ static int zonefs_statfs(struct dentry *dentry, struct kstatfs *buf) struct super_block *sb = dentry->d_sb; struct zonefs_sb_info *sbi = ZONEFS_SB(sb); enum zonefs_ztype t; - u64 fsid; buf->f_type = ZONEFS_MAGIC; buf->f_bsize = sb->s_blocksize; @@ -1127,9 +1126,7 @@ static int zonefs_statfs(struct dentry *dentry, struct kstatfs *buf) spin_unlock(&sbi->s_lock); - fsid = le64_to_cpup((void *)sbi->s_uuid.b) ^ - le64_to_cpup((void *)sbi->s_uuid.b + sizeof(u64)); - buf->f_fsid = u64_to_fsid(fsid); + buf->f_fsid = uuid_to_fsid(sbi->s_uuid.b); return 0; } diff --git a/include/linux/statfs.h b/include/linux/statfs.h index 20f695b..02c8626 100644 --- a/include/linux/statfs.h +++ b/include/linux/statfs.h @@ -4,6 +4,7 @@ #include #include +#include struct kstatfs { long f_type; @@ -50,4 +51,11 @@ static inline __kernel_fsid_t u64_to_fsid(u64 v) return (__kernel_fsid_t){.val = {(u32)v, (u32)(v>>32)}}; } +/* Fold 16 bytes uuid to 64 bit fsid */ +static inline __kernel_fsid_t uuid_to_fsid(__u8 *uuid) +{ + return u64_to_fsid(le64_to_cpup((void *)uuid) ^ + le64_to_cpup((void *)(uuid + sizeof(u64)))); +} + #endif -- 2.7.4