In data=ordered mode jinode needs to be attached to the xattr inode when
writing data to it. Attachment normally occurs during file open for regular
files. Since we are not using file interface to write to the xattr inode,
the jinode attach needs to be done manually.
Otherwise the following crash occurs in data=ordered mode.
BUG: unable to handle kernel NULL pointer dereference at (null)
IP: jbd2_journal_file_inode+0x37/0x110
PGD 13b3c0067
P4D 13b3c0067
PUD 137660067
PMD 0
Oops: 0000 [#1] SMP
CPU: 3 PID: 1877 Comm: python Not tainted 4.12.0-rc1+ #749
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011
task: ffff88010e368980 task.stack: ffffc90000374000
RIP: 0010:jbd2_journal_file_inode+0x37/0x110
RSP: 0018:ffffc90000377980 EFLAGS: 00010246
RAX: 0000000000000000 RBX: ffff880123b06230 RCX: 0000000000280000
RDX: 0000000000000006 RSI: 0000000000000000 RDI: ffff88012c8585d0
RBP: ffffc900003779b0 R08: 0000000000000202 R09: 0000000000000001
R10: 0000000000000000 R11: 0000000000000400 R12: ffff8801111f81c0
R13: ffff88013b2b6800 R14: ffffc90000377ab0 R15: 0000000000000001
FS: 00007f0c99b77740(0000) GS:ffff88013fd80000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000000000 CR3: 0000000136d91000 CR4: 00000000000006e0
Call Trace:
jbd2_journal_inode_add_write+0xe/0x10
ext4_map_blocks+0x59e/0x620
ext4_xattr_set_entry+0x501/0x7d0
ext4_xattr_block_set+0x1b2/0x9b0
ext4_xattr_set_handle+0x322/0x4f0
ext4_xattr_set+0x144/0x1a0
ext4_xattr_user_set+0x34/0x40
__vfs_setxattr+0x66/0x80
__vfs_setxattr_noperm+0x69/0x1c0
vfs_setxattr+0xa2/0xb0
setxattr+0x12e/0x150
path_setxattr+0x87/0xb0
SyS_setxattr+0xf/0x20
entry_SYSCALL_64_fastpath+0x18/0xad
Signed-off-by: Tahsin Erdogan <tahsin@xxxxxxxxxx>
---
fs/ext4/xattr.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/fs/ext4/xattr.c b/fs/ext4/xattr.c
index 12210fe87ea3..8e123533315f 100644
--- a/fs/ext4/xattr.c
+++ b/fs/ext4/xattr.c
@@ -826,6 +826,7 @@ static struct inode *ext4_xattr_inode_create(handle_t *handle,
struct inode *inode)
{
struct inode *ea_inode = NULL;
+ int err;
/*
* Let the next inode be the goal, so we try and allocate the EA inode
@@ -848,6 +849,11 @@ static struct inode *ext4_xattr_inode_create(handle_t *handle,
*/
EXT4_XATTR_INODE_SET_PARENT(ea_inode, inode->i_ino);
unlock_new_inode(ea_inode);
+ err = ext4_inode_attach_jinode(ea_inode);
+ if (err) {
+ iput(ea_inode);
+ return ERR_PTR(err);
+ }
}
return ea_inode;
--
2.13.1.611.g7e3b11ae1-goog
