On Thu, Mar 25, 2021 at 06:12:19PM +0000, Leah Rumancik wrote: > Zero out filename field when file is deleted. Also, add mount option > nowipe_filename to disable this filename wipeout if desired. > > Signed-off-by: Leah Rumancik <leah.rumancik@xxxxxxxxx> I'm totally cribbing off of the previous decade's dirname wipe patch[1]. [1] https://lore.kernel.org/linux-ext4/1309468923-5677-1-git-send-email-achender@xxxxxxxxxxxxxxxxxx/T/#ma0442145ca50bb6e62f8e3502d607c758dd24418 > --- > fs/ext4/ext4.h | 1 + > fs/ext4/namei.c | 4 ++++ > fs/ext4/super.c | 11 ++++++++++- > 3 files changed, 15 insertions(+), 1 deletion(-) > > diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h > index 826a56e3bbd2..8011418176bc 100644 > --- a/fs/ext4/ext4.h > +++ b/fs/ext4/ext4.h > @@ -1247,6 +1247,7 @@ struct ext4_inode_info { > #define EXT4_MOUNT2_JOURNAL_FAST_COMMIT 0x00000010 /* Journal fast commit */ > #define EXT4_MOUNT2_DAX_NEVER 0x00000020 /* Do not allow Direct Access */ > #define EXT4_MOUNT2_DAX_INODE 0x00000040 /* For printing options only */ > +#define EXT4_MOUNT2_WIPE_FILENAME 0x00000080 /* Wipe filename on del entry */ > > > #define clear_opt(sb, opt) EXT4_SB(sb)->s_mount_opt &= \ > diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c > index 883e2a7cd4ab..ae6ecabd4d97 100644 > --- a/fs/ext4/namei.c > +++ b/fs/ext4/namei.c > @@ -2492,6 +2492,10 @@ int ext4_generic_delete_entry(struct inode *dir, > else > de->inode = 0; > inode_inc_iversion(dir); > + > + if (test_opt2(dir->i_sb, WIPE_FILENAME)) > + memset(de_del->name, 0, de_del->name_len); You probably ought to erase the file type information too. > + > return 0; > } > i += ext4_rec_len_from_disk(de->rec_len, blocksize); > diff --git a/fs/ext4/super.c b/fs/ext4/super.c > index b9693680463a..5e8737b3f171 100644 > --- a/fs/ext4/super.c > +++ b/fs/ext4/super.c > @@ -1688,7 +1688,7 @@ enum { > Opt_dioread_nolock, Opt_dioread_lock, > Opt_discard, Opt_nodiscard, Opt_init_itable, Opt_noinit_itable, > Opt_max_dir_size_kb, Opt_nojournal_checksum, Opt_nombcache, > - Opt_prefetch_block_bitmaps, > + Opt_prefetch_block_bitmaps, Opt_nowipe_filename, > #ifdef CONFIG_EXT4_DEBUG > Opt_fc_debug_max_replay, Opt_fc_debug_force > #endif > @@ -1787,6 +1787,7 @@ static const match_table_t tokens = { > {Opt_test_dummy_encryption, "test_dummy_encryption"}, > {Opt_inlinecrypt, "inlinecrypt"}, > {Opt_nombcache, "nombcache"}, > + {Opt_nowipe_filename, "nowipe_filename"}, > {Opt_nombcache, "no_mbcache"}, /* for backward compatibility */ > {Opt_prefetch_block_bitmaps, "prefetch_block_bitmaps"}, > {Opt_removed, "check=none"}, /* mount option from ext2/3 */ > @@ -2007,6 +2008,8 @@ static const struct mount_opts { > {Opt_max_dir_size_kb, 0, MOPT_GTE0}, > {Opt_test_dummy_encryption, 0, MOPT_STRING}, > {Opt_nombcache, EXT4_MOUNT_NO_MBCACHE, MOPT_SET}, > + {Opt_nowipe_filename, EXT4_MOUNT2_WIPE_FILENAME, MOPT_CLEAR | MOPT_2 | > + MOPT_EXT4_ONLY}, > {Opt_prefetch_block_bitmaps, EXT4_MOUNT_PREFETCH_BLOCK_BITMAPS, > MOPT_SET}, > #ifdef CONFIG_EXT4_DEBUG > @@ -2621,6 +2624,10 @@ static int _ext4_show_options(struct seq_file *seq, struct super_block *sb, > } else if (test_opt2(sb, DAX_INODE)) { > SEQ_OPTS_PUTS("dax=inode"); > } > + > + if (!test_opt2(sb, WIPE_FILENAME)) > + SEQ_OPTS_PUTS("nowipe_filename"); Interesting how this time around it's a mount option... At the risk of dredging up bad old memories, any chance you'd want to select this if the file being unlinked has EXT4_SECRM_FL set? Also, uh, I guess this is a change in default behavior? Now you have to opt-out of wiping filenames? I suppose it's not a big deal performance-wise since we're logging and writing buffers to disk anyway, but I bet there's at last a few people who have recovered accidental deltree invocations this way... --D > + > ext4_show_quota_options(seq, sb); > return 0; > } > @@ -4161,6 +4168,8 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent) > if (def_mount_opts & EXT4_DEFM_DISCARD) > set_opt(sb, DISCARD); > > + set_opt2(sb, WIPE_FILENAME); > + > sbi->s_resuid = make_kuid(&init_user_ns, le16_to_cpu(es->s_def_resuid)); > sbi->s_resgid = make_kgid(&init_user_ns, le16_to_cpu(es->s_def_resgid)); > sbi->s_commit_interval = JBD2_DEFAULT_MAX_COMMIT_AGE * HZ; > -- > 2.31.0.291.g576ba9dcdaf-goog >
