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f2fs: fix to check extent cache in f2fs_drop_extent_tree 

If noextent_cache mount option is on, we will never initialize extent tree
in inode, but still we're going to access it in f2fs_drop_extent_tree,
result in kernel panic as below:

 BUG: unable to handle kernel NULL pointer dereference at 0000000000000038
 IP: _raw_write_lock+0xc/0x30
 Call Trace:
  ? f2fs_drop_extent_tree+0x41/0x70 [f2fs]
  f2fs_fallocate+0x5a0/0xdd0 [f2fs]
  ? common_file_perm+0x47/0xc0
  ? apparmor_file_permission+0x1a/0x20
  vfs_fallocate+0x15b/0x290
  SyS_fallocate+0x44/0x70
  do_syscall_64+0x6e/0x160
  entry_SYSCALL64_slow_path+0x25/0x25

This patch fixes to check extent cache status before using in
f2fs_drop_extent_tree.

Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
hifive-unleashed-5.1
Chao Yu 2018-01-27 17:29:49 +08:00 committed by Jaegeuk Kim
parent 4d817ae099
commit bf617f7a92
1 changed files with 3 additions and 0 deletions
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3
fs/f2fs/extent_cache.c
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@ -706,6 +706,9 @@ void f2fs_drop_extent_tree(struct inode *inode)
struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
struct extent_tree *et = F2FS_I(inode)->extent_tree;
if (!f2fs_may_extent_tree(inode))
return;
set_inode_flag(inode, FI_NO_EXTENT);
write_lock(&et->lock);