| Message ID | 2fc070a3990716077dee122740f21abcea8121a8.1691505882.git.sweettea-kernel@dorminy.me (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | fscrypt: add extent encryption | expand |
Sweet Tea Dorminy <sweettea-kernel@dorminy.me> writes: > btrfs occasionally splits in-memory extents while holding a mutex. This > means we can't just copy the info, since setting up a new inlinecrypt > key requires taking a semaphore. Thus adding a mechanism to split > extents and merely take a new reference on the info is necessary. > > Signed-off-by: Sweet Tea Dorminy <sweettea-kernel@dorminy.me> > --- > fs/crypto/fscrypt_private.h | 5 +++++ > fs/crypto/keysetup.c | 18 +++++++++++++++++- > include/linux/fscrypt.h | 2 ++ > 3 files changed, 24 insertions(+), 1 deletion(-) > > diff --git a/fs/crypto/fscrypt_private.h b/fs/crypto/fscrypt_private.h > index cd29c71b4349..03be2c136c0e 100644 > --- a/fs/crypto/fscrypt_private.h > +++ b/fs/crypto/fscrypt_private.h > @@ -287,6 +287,11 @@ struct fscrypt_info { > > /* Hashed inode number. Only set for IV_INO_LBLK_32 */ > u32 ci_hashed_ino; > + > + /* Reference count. Normally 1, unless a extent info is shared by > + * several virtual extents. > + */ > + refcount_t refs; > }; > > typedef enum { > diff --git a/fs/crypto/keysetup.c b/fs/crypto/keysetup.c > index 8d50716bdf11..12c3851b7cd6 100644 > --- a/fs/crypto/keysetup.c > +++ b/fs/crypto/keysetup.c > @@ -598,7 +598,7 @@ static void put_crypt_info(struct fscrypt_info *ci) > { > struct fscrypt_master_key *mk; > > - if (!ci) > + if (!ci || !refcount_dec_and_test(&ci->refs)) > return; > > if (ci->ci_enc_key) { > @@ -686,6 +686,7 @@ fscrypt_setup_encryption_info(struct inode *inode, > crypt_info->ci_inode = inode; > crypt_info->ci_sb = inode->i_sb; > crypt_info->ci_policy = *policy; > + refcount_set(&crypt_info->refs, 1); > memcpy(crypt_info->ci_nonce, nonce, FSCRYPT_FILE_NONCE_SIZE); > > mode = select_encryption_mode(&crypt_info->ci_policy, inode); > @@ -1046,6 +1047,21 @@ int fscrypt_load_extent_info(struct inode *inode, void *buf, size_t len, > } > EXPORT_SYMBOL_GPL(fscrypt_load_extent_info); > > +/** > + * fscrypt_get_extent_info_ref() - mark a second extent using the same info > + * @info: the info to be used by another extent > + * > + * Sometimes, an existing extent must be split into multiple extents in memory. > + * In such a case, this function allows multiple extents to use the same extent > + * info without allocating or taking any lock, which is necessary in certain IO > + * paths. > + */ > +void fscrypt_get_extent_info_ref(struct fscrypt_info *info) > +{ > + if (info) > + refcount_inc(&info->refs); > +} > + There's an EXPORT_SYMBOL_GPL() missing here, right? Cheers,
On 8/10/23 11:51, Luís Henriques wrote: > Sweet Tea Dorminy <sweettea-kernel@dorminy.me> writes: > >> btrfs occasionally splits in-memory extents while holding a mutex. This >> means we can't just copy the info, since setting up a new inlinecrypt >> key requires taking a semaphore. Thus adding a mechanism to split >> extents and merely take a new reference on the info is necessary. >> >> Signed-off-by: Sweet Tea Dorminy <sweettea-kernel@dorminy.me> >> --- >> fs/crypto/fscrypt_private.h | 5 +++++ >> fs/crypto/keysetup.c | 18 +++++++++++++++++- >> include/linux/fscrypt.h | 2 ++ >> 3 files changed, 24 insertions(+), 1 deletion(-) >> >> diff --git a/fs/crypto/fscrypt_private.h b/fs/crypto/fscrypt_private.h >> index cd29c71b4349..03be2c136c0e 100644 >> --- a/fs/crypto/fscrypt_private.h >> +++ b/fs/crypto/fscrypt_private.h >> @@ -287,6 +287,11 @@ struct fscrypt_info { >> >> /* Hashed inode number. Only set for IV_INO_LBLK_32 */ >> u32 ci_hashed_ino; >> + >> + /* Reference count. Normally 1, unless a extent info is shared by >> + * several virtual extents. >> + */ >> + refcount_t refs; >> }; >> >> typedef enum { >> diff --git a/fs/crypto/keysetup.c b/fs/crypto/keysetup.c >> index 8d50716bdf11..12c3851b7cd6 100644 >> --- a/fs/crypto/keysetup.c >> +++ b/fs/crypto/keysetup.c >> @@ -598,7 +598,7 @@ static void put_crypt_info(struct fscrypt_info *ci) >> { >> struct fscrypt_master_key *mk; >> >> - if (!ci) >> + if (!ci || !refcount_dec_and_test(&ci->refs)) >> return; >> >> if (ci->ci_enc_key) { >> @@ -686,6 +686,7 @@ fscrypt_setup_encryption_info(struct inode *inode, >> crypt_info->ci_inode = inode; >> crypt_info->ci_sb = inode->i_sb; >> crypt_info->ci_policy = *policy; >> + refcount_set(&crypt_info->refs, 1); >> memcpy(crypt_info->ci_nonce, nonce, FSCRYPT_FILE_NONCE_SIZE); >> >> mode = select_encryption_mode(&crypt_info->ci_policy, inode); >> @@ -1046,6 +1047,21 @@ int fscrypt_load_extent_info(struct inode *inode, void *buf, size_t len, >> } >> EXPORT_SYMBOL_GPL(fscrypt_load_extent_info); >> >> +/** >> + * fscrypt_get_extent_info_ref() - mark a second extent using the same info >> + * @info: the info to be used by another extent >> + * >> + * Sometimes, an existing extent must be split into multiple extents in memory. >> + * In such a case, this function allows multiple extents to use the same extent >> + * info without allocating or taking any lock, which is necessary in certain IO >> + * paths. >> + */ >> +void fscrypt_get_extent_info_ref(struct fscrypt_info *info) >> +{ >> + if (info) >> + refcount_inc(&info->refs); >> +} >> + > > There's an EXPORT_SYMBOL_GPL() missing here, right? > > Cheers, Oof, guess I need to add 'build btrfs as a module' to my preflight checklist. Thank you.
diff --git a/fs/crypto/fscrypt_private.h b/fs/crypto/fscrypt_private.h index cd29c71b4349..03be2c136c0e 100644 --- a/fs/crypto/fscrypt_private.h +++ b/fs/crypto/fscrypt_private.h @@ -287,6 +287,11 @@ struct fscrypt_info { /* Hashed inode number. Only set for IV_INO_LBLK_32 */ u32 ci_hashed_ino; + + /* Reference count. Normally 1, unless a extent info is shared by + * several virtual extents. + */ + refcount_t refs; }; typedef enum { diff --git a/fs/crypto/keysetup.c b/fs/crypto/keysetup.c index 8d50716bdf11..12c3851b7cd6 100644 --- a/fs/crypto/keysetup.c +++ b/fs/crypto/keysetup.c @@ -598,7 +598,7 @@ static void put_crypt_info(struct fscrypt_info *ci) { struct fscrypt_master_key *mk; - if (!ci) + if (!ci || !refcount_dec_and_test(&ci->refs)) return; if (ci->ci_enc_key) { @@ -686,6 +686,7 @@ fscrypt_setup_encryption_info(struct inode *inode, crypt_info->ci_inode = inode; crypt_info->ci_sb = inode->i_sb; crypt_info->ci_policy = *policy; + refcount_set(&crypt_info->refs, 1); memcpy(crypt_info->ci_nonce, nonce, FSCRYPT_FILE_NONCE_SIZE); mode = select_encryption_mode(&crypt_info->ci_policy, inode); @@ -1046,6 +1047,21 @@ int fscrypt_load_extent_info(struct inode *inode, void *buf, size_t len, } EXPORT_SYMBOL_GPL(fscrypt_load_extent_info); +/** + * fscrypt_get_extent_info_ref() - mark a second extent using the same info + * @info: the info to be used by another extent + * + * Sometimes, an existing extent must be split into multiple extents in memory. + * In such a case, this function allows multiple extents to use the same extent + * info without allocating or taking any lock, which is necessary in certain IO + * paths. + */ +void fscrypt_get_extent_info_ref(struct fscrypt_info *info) +{ + if (info) + refcount_inc(&info->refs); +} + /** * fscrypt_put_encryption_info() - free most of an inode's fscrypt data * @inode: an inode being evicted diff --git a/include/linux/fscrypt.h b/include/linux/fscrypt.h index 4ba624beea91..b67054a2c965 100644 --- a/include/linux/fscrypt.h +++ b/include/linux/fscrypt.h @@ -370,6 +370,8 @@ void fscrypt_free_extent_info(struct fscrypt_info **info_ptr); int fscrypt_load_extent_info(struct inode *inode, void *buf, size_t len, struct fscrypt_info **info_ptr); +void fscrypt_get_extent_info_ref(struct fscrypt_info *info); + /* fname.c */ int fscrypt_fname_encrypt(const struct inode *inode, const struct qstr *iname, u8 *out, unsigned int olen);
btrfs occasionally splits in-memory extents while holding a mutex. This means we can't just copy the info, since setting up a new inlinecrypt key requires taking a semaphore. Thus adding a mechanism to split extents and merely take a new reference on the info is necessary. Signed-off-by: Sweet Tea Dorminy <sweettea-kernel@dorminy.me> --- fs/crypto/fscrypt_private.h | 5 +++++ fs/crypto/keysetup.c | 18 +++++++++++++++++- include/linux/fscrypt.h | 2 ++ 3 files changed, 24 insertions(+), 1 deletion(-)