Make ext4 able to parse vfs_shift_uids and vfs_shift_gids options and set the appropriate flags into the super_block structure.
vfs_shift_uids and vfs_shift_gids allow mounts that show up in a mount namespace that supports VFS UID/GID shifts on inodes to perform translation from in kernel virtual view into on-disk view and vice versa. This allows user namespaces users to be able to access, read and write inodes on these mounts. Signed-off-by: Dongsu Park <[email protected]> Signed-off-by: Djalal Harouni <[email protected]> --- fs/ext4/super.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+) diff --git a/fs/ext4/super.c b/fs/ext4/super.c index 304c712..c9a20c0 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -1194,6 +1194,7 @@ 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_vfs_shift_uids, Opt_vfs_shift_gids, }; static const match_table_t tokens = { @@ -1279,6 +1280,8 @@ static const match_table_t tokens = { {Opt_removed, "reservation"}, /* mount option from ext2/3 */ {Opt_removed, "noreservation"}, /* mount option from ext2/3 */ {Opt_removed, "journal=%u"}, /* mount option from ext2/3 */ + {Opt_vfs_shift_uids, "vfs_shift_uids"}, + {Opt_vfs_shift_gids, "vfs_shift_gids"}, {Opt_err, NULL}, }; @@ -1521,8 +1524,15 @@ static int handle_mount_opt(struct super_block *sb, char *opt, int token, case Opt_nolazytime: sb->s_flags &= ~MS_LAZYTIME; return 1; + case Opt_vfs_shift_uids: + sb->s_iflags |= SB_I_VFS_SHIFT_UIDS; + return 1; + case Opt_vfs_shift_gids: + sb->s_iflags |= SB_I_VFS_SHIFT_GIDS; + return 1; } + for (m = ext4_mount_opts; m->token != Opt_err; m++) if (token == m->token) break; @@ -1920,6 +1930,10 @@ static int _ext4_show_options(struct seq_file *seq, struct super_block *sb, SEQ_OPTS_PRINT("max_dir_size_kb=%u", sbi->s_max_dir_size_kb); if (test_opt(sb, DATA_ERR_ABORT)) SEQ_OPTS_PUTS("data_err=abort"); + if (sb->s_iflags & SB_I_VFS_SHIFT_UIDS) + SEQ_OPTS_PUTS("vfs_shift_uids"); + if (sb->s_iflags & SB_I_VFS_SHIFT_GIDS) + SEQ_OPTS_PUTS("vfs_shift_gids"); ext4_show_quota_options(seq, sb); return 0; -- 2.5.5
