The check for a fast symlink in the presence of only an external xattr inode is incorrect. If a fast symlink does not have an xattr block (i_file_acl == 0), but does have an external xattr inode that increases inode i_blocks, then the check for a fast symlink will incorrectly fail and __ext4_iget()->ext4_ind_check_inode() will report the inode is corrupt when it "validates" i_data[] on the next read:

# ln -s foo /mnt/tmp/bar # setfattr -h -n trusted.test \ -v "$(yes | head -n 4000)" /mnt/tmp/bar # umount /mnt/tmp # mount /mnt/tmp # ls -l /mnt/tmp ls: cannot access '/mnt/tmp/bar': Structure needs cleaning total 4 ? l?????????? ? ? ? ? ? bar # dmesg | tail -1 EXT4-fs error (device dm-8): __ext4_iget:5098: inode #24578: block 7303014: comm ls: invalid block

(note that "block 7303014" = 0x6f6f66 = "foo" in LE order).

ext4_inode_is_fast_symlink() should check the superblock EXT4_FEATURE_INCOMPAT_EA_INODE feature flag, not the inode EXT4_EA_INODE_FL, since the latter is only set on the xattr inode itself, and not on the inode that uses this xattr.

Cc: stable@vger.kernel.org Fixes: fc82228a5e38 ("ext4: support fast symlinks from ext3 file systems") Signed-off-by: Andreas Dilger adilger@whamcloud.com Reviewed-by: Li Dongyang dongyangli@ddn.com Reviewed-by: Alex Zhuravlev bzzz@whamcloud.com Reviewed-by: Oleg Drokin green@whamcloud.com Reviewed-on: https://review.whamcloud.com/59879 Lustre-bug-id: https://jira.whamcloud.com/browse/LU-19121 --- fs/ext4/inode.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index be9a4cba35fd..caca88521c75 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -146,7 +146,7 @@ static inline int ext4_begin_ordered_truncate(struct inode *inode, */ int ext4_inode_is_fast_symlink(struct inode *inode) { - if (!(EXT4_I(inode)->i_flags & EXT4_EA_INODE_FL)) { + if (!ext4_has_feature_ea_inode(inode->i_sb)) { int ea_blocks = EXT4_I(inode)->i_file_acl ? EXT4_CLUSTER_SIZE(inode->i_sb) >> 9 : 0;