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| author | Christoph Hellwig <hch@lst.de> | 2026-02-02 07:06:40 +0100 |
|---|---|---|
| committer | Eric Biggers <ebiggers@kernel.org> | 2026-02-04 11:31:54 -0800 |
| commit | f77f281b61183a5c0b87e6a4d101c70bd32c1c79 (patch) | |
| tree | bdca555b35133f7d898fd43472eb815d960d5e51 /fs/f2fs | |
| parent | b0160e4501bb3572d9ef6e4f8edf758193ee37aa (diff) | |
| download | linux-next-f77f281b61183a5c0b87e6a4d101c70bd32c1c79.tar.gz linux-next-f77f281b61183a5c0b87e6a4d101c70bd32c1c79.zip | |
fsverity: use a hashtable to find the fsverity_info
Use the kernel's resizable hash table (rhashtable) to find the
fsverity_info. This way file systems that want to support fsverity don't
have to bloat every inode in the system with an extra pointer. The
trade-off is that looking up the fsverity_info is a bit more expensive
now, but the main operations are still dominated by I/O and hashing
overhead.
The rhashtable implementations requires no external synchronization, and
the _fast versions of the APIs provide the RCU critical sections required
by the implementation. Because struct fsverity_info is only removed on
inode eviction and does not contain a reference count, there is no need
for an extended critical section to grab a reference or validate the
object state. The file open path uses rhashtable_lookup_get_insert_fast,
which can either find an existing object for the hash key or insert a
new one in a single atomic operation, so that concurrent opens never
instantiate duplicate fsverity_info structure. FS_IOC_ENABLE_VERITY must
already be synchronized by a combination of i_rwsem and file system flags
and uses rhashtable_lookup_insert_fast, which errors out on an existing
object for the hash key as an additional safety check.
Because insertion into the hash table now happens before S_VERITY is set,
fsverity just becomes a barrier and a flag check and doesn't have to look
up the fsverity_info at all, so there is only a single lookup per
->read_folio or ->readahead invocation. For btrfs there is an additional
one for each bio completion, while for ext4 and f2fs the fsverity_info
is stored in the per-I/O context and reused for the completion workqueue.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: "Darrick J. Wong" <djwong@kernel.org>
Link: https://lore.kernel.org/r/20260202060754.270269-12-hch@lst.de
[EB: folded in fix for missing fsverity_free_info()]
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
Diffstat (limited to 'fs/f2fs')
| -rw-r--r-- | fs/f2fs/f2fs.h | 3 | ||||
| -rw-r--r-- | fs/f2fs/super.c | 3 | ||||
| -rw-r--r-- | fs/f2fs/verity.c | 2 |
3 files changed, 0 insertions, 8 deletions
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h index f2fcadc7a6fe..8ee8a7bc012c 100644 --- a/fs/f2fs/f2fs.h +++ b/fs/f2fs/f2fs.h @@ -974,9 +974,6 @@ struct f2fs_inode_info { #ifdef CONFIG_FS_ENCRYPTION struct fscrypt_inode_info *i_crypt_info; /* filesystem encryption info */ #endif -#ifdef CONFIG_FS_VERITY - struct fsverity_info *i_verity_info; /* filesystem verity info */ -#endif }; static inline void get_read_extent_info(struct extent_info *ext, diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c index c4c225e09dc4..cd00d030edda 100644 --- a/fs/f2fs/super.c +++ b/fs/f2fs/super.c @@ -504,9 +504,6 @@ static void init_once(void *foo) #ifdef CONFIG_FS_ENCRYPTION fi->i_crypt_info = NULL; #endif -#ifdef CONFIG_FS_VERITY - fi->i_verity_info = NULL; -#endif } #ifdef CONFIG_QUOTA diff --git a/fs/f2fs/verity.c b/fs/f2fs/verity.c index de2c87621319..92ebcc19cab0 100644 --- a/fs/f2fs/verity.c +++ b/fs/f2fs/verity.c @@ -278,8 +278,6 @@ static int f2fs_write_merkle_tree_block(struct file *file, const void *buf, } const struct fsverity_operations f2fs_verityops = { - .inode_info_offs = (int)offsetof(struct f2fs_inode_info, i_verity_info) - - (int)offsetof(struct f2fs_inode_info, vfs_inode), .begin_enable_verity = f2fs_begin_enable_verity, .end_enable_verity = f2fs_end_enable_verity, .get_verity_descriptor = f2fs_get_verity_descriptor, |