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authorEric Biggers <ebiggers@google.com>2020-09-16 21:11:27 -0700
committerEric Biggers <ebiggers@google.com>2020-09-22 06:48:35 -0700
commite075b6901047cd4c70b93cfcbe5f67dbc5741fb6 (patch)
treee79069f3ffa942e9408cdce0bebdb62731bc5727 /fs/f2fs/namei.c
parent02ce5316afc86274c55c7b07a81ad6411d28f077 (diff)
f2fs: use fscrypt_prepare_new_inode() and fscrypt_set_context()
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> Acked-by: Jaegeuk Kim <jaegeuk@kernel.org> Link: https://lore.kernel.org/r/20200917041136.178600-5-ebiggers@kernel.org Signed-off-by: Eric Biggers <ebiggers@google.com>
Diffstat (limited to 'fs/f2fs/namei.c')
-rw-r--r--fs/f2fs/namei.c7
1 files changed, 6 insertions, 1 deletions
diff --git a/fs/f2fs/namei.c b/fs/f2fs/namei.c
index 84e4bbc1a64d..45f324511a19 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)) {