| Message ID | 20200913083620.170627-1-ebiggers@kernel.org |
|---|---|
| Headers | show |
| Series | fscrypt: improve file creation flow | expand |
On 09/13, Eric Biggers wrote: > From: Eric Biggers <ebiggers@google.com> > > Convert f2fs to use the new functions fscrypt_prepare_new_inode() and > fscrypt_set_context(). This avoids calling > fscrypt_get_encryption_info() from under f2fs_lock_op(), which can > deadlock because fscrypt_get_encryption_info() isn't GFP_NOFS-safe. > > For more details about this problem, see the earlier patch > "fscrypt: add fscrypt_prepare_new_inode() and fscrypt_set_context()". > > This also fixes a f2fs-specific deadlock when the filesystem is mounted > with '-o test_dummy_encryption' and a file is created in an unencrypted > directory other than the root directory: > > INFO: task touch:207 blocked for more than 30 seconds. > Not tainted 5.9.0-rc4-00099-g729e3d0919844 #2 > "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. > task:touch state:D stack: 0 pid: 207 ppid: 167 flags:0x00000000 > Call Trace: > [...] > lock_page include/linux/pagemap.h:548 [inline] > pagecache_get_page+0x25e/0x310 mm/filemap.c:1682 > find_or_create_page include/linux/pagemap.h:348 [inline] > grab_cache_page include/linux/pagemap.h:424 [inline] > f2fs_grab_cache_page fs/f2fs/f2fs.h:2395 [inline] > f2fs_grab_cache_page fs/f2fs/f2fs.h:2373 [inline] > __get_node_page.part.0+0x39/0x2d0 fs/f2fs/node.c:1350 > __get_node_page fs/f2fs/node.c:35 [inline] > f2fs_get_node_page+0x2e/0x60 fs/f2fs/node.c:1399 > read_inline_xattr+0x88/0x140 fs/f2fs/xattr.c:288 > lookup_all_xattrs+0x1f9/0x2c0 fs/f2fs/xattr.c:344 > f2fs_getxattr+0x9b/0x160 fs/f2fs/xattr.c:532 > f2fs_get_context+0x1e/0x20 fs/f2fs/super.c:2460 > fscrypt_get_encryption_info+0x9b/0x450 fs/crypto/keysetup.c:472 > fscrypt_inherit_context+0x2f/0xb0 fs/crypto/policy.c:640 > f2fs_init_inode_metadata+0xab/0x340 fs/f2fs/dir.c:540 > f2fs_add_inline_entry+0x145/0x390 fs/f2fs/inline.c:621 > f2fs_add_dentry+0x31/0x80 fs/f2fs/dir.c:757 > f2fs_do_add_link+0xcd/0x130 fs/f2fs/dir.c:798 > f2fs_add_link fs/f2fs/f2fs.h:3234 [inline] > f2fs_create+0x104/0x290 fs/f2fs/namei.c:344 > lookup_open.isra.0+0x2de/0x500 fs/namei.c:3103 > open_last_lookups+0xa9/0x340 fs/namei.c:3177 > path_openat+0x8f/0x1b0 fs/namei.c:3365 > do_filp_open+0x87/0x130 fs/namei.c:3395 > do_sys_openat2+0x96/0x150 fs/open.c:1168 > [...] > > That happened because f2fs_add_inline_entry() locks the directory > inode's page in order to add the dentry, then f2fs_get_context() tries > to lock it recursively in order to read the encryption xattr. This > problem is specific to "test_dummy_encryption" because normally the > directory's fscrypt_info would be set up prior to > f2fs_add_inline_entry() in order to encrypt the new filename. > > Regardless, the new design fixes this test_dummy_encryption deadlock as > well as potential deadlocks with fs reclaim, by setting up any needed > fscrypt_info structs prior to taking so many locks. > > The test_dummy_encryption deadlock was reported by Daniel Rosenberg. > > Reported-by: Daniel Rosenberg <drosen@google.com> > Signed-off-by: Eric Biggers <ebiggers@google.com> Thanks. Acked-by: Jaegeuk Kim <jaegeuk@kernel.org> > --- > fs/f2fs/dir.c | 2 +- > fs/f2fs/f2fs.h | 23 ----------------------- > fs/f2fs/namei.c | 7 ++++++- > 3 files changed, 7 insertions(+), 25 deletions(-) > > diff --git a/fs/f2fs/dir.c b/fs/f2fs/dir.c > index b2530b9507bd9..414bc94fbd546 100644 > --- a/fs/f2fs/dir.c > +++ b/fs/f2fs/dir.c > @@ -537,7 +537,7 @@ struct page *f2fs_init_inode_metadata(struct inode *inode, struct inode *dir, > goto put_error; > > if (IS_ENCRYPTED(inode)) { > - err = fscrypt_inherit_context(dir, inode, page, false); > + err = fscrypt_set_context(inode, page); > if (err) > goto put_error; > } > diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h > index d9e52a7f3702f..0503371f88ed4 100644 > --- a/fs/f2fs/f2fs.h > +++ b/fs/f2fs/f2fs.h > @@ -1315,13 +1315,6 @@ enum fsync_mode { > #define IS_IO_TRACED_PAGE(page) (0) > #endif > > -#ifdef CONFIG_FS_ENCRYPTION > -#define DUMMY_ENCRYPTION_ENABLED(sbi) \ > - (unlikely(F2FS_OPTION(sbi).dummy_enc_ctx.ctx != NULL)) > -#else > -#define DUMMY_ENCRYPTION_ENABLED(sbi) (0) > -#endif > - > /* For compression */ > enum compress_algorithm_type { > COMPRESS_LZO, > @@ -4022,22 +4015,6 @@ static inline bool f2fs_lfs_mode(struct f2fs_sb_info *sbi) > return F2FS_OPTION(sbi).fs_mode == FS_MODE_LFS; > } > > -static inline bool f2fs_may_encrypt(struct inode *dir, struct inode *inode) > -{ > -#ifdef CONFIG_FS_ENCRYPTION > - struct f2fs_sb_info *sbi = F2FS_I_SB(dir); > - umode_t mode = inode->i_mode; > - > - /* > - * If the directory encrypted or dummy encryption enabled, > - * then we should encrypt the inode. > - */ > - if (IS_ENCRYPTED(dir) || DUMMY_ENCRYPTION_ENABLED(sbi)) > - return (S_ISREG(mode) || S_ISDIR(mode) || S_ISLNK(mode)); > -#endif > - return false; > -} > - > static inline bool f2fs_may_compress(struct inode *inode) > { > if (IS_SWAPFILE(inode) || f2fs_is_pinned_file(inode) || > diff --git a/fs/f2fs/namei.c b/fs/f2fs/namei.c > index 84e4bbc1a64de..45f324511a19e 100644 > --- a/fs/f2fs/namei.c > +++ b/fs/f2fs/namei.c > @@ -28,6 +28,7 @@ static struct inode *f2fs_new_inode(struct inode *dir, umode_t mode) > nid_t ino; > struct inode *inode; > bool nid_free = false; > + bool encrypt = false; > int xattr_size = 0; > int err; > > @@ -69,13 +70,17 @@ static struct inode *f2fs_new_inode(struct inode *dir, umode_t mode) > F2FS_I(inode)->i_projid = make_kprojid(&init_user_ns, > F2FS_DEF_PROJID); > > + err = fscrypt_prepare_new_inode(dir, inode, &encrypt); > + if (err) > + goto fail_drop; > + > err = dquot_initialize(inode); > if (err) > goto fail_drop; > > set_inode_flag(inode, FI_NEW_INODE); > > - if (f2fs_may_encrypt(dir, inode)) > + if (encrypt) > f2fs_set_encrypted_inode(inode); > > if (f2fs_sb_has_extra_attr(sbi)) { > -- > 2.28.0 > > > > _______________________________________________ > Linux-f2fs-devel mailing list > Linux-f2fs-devel@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/linux-f2fs-devel