tune2fs: always check disable_uninit_bg() return code

Enhance disable_uninit_bg() to return error codes -- if something goes
wrong, we want to flag the FS as needing a fsck and exit.  Mr. Reardon
discovered that tune2fs -O ^metadata_csum on a FS with a corrupt
bitmap would leave the FS in a weird state.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reported-by: TR Reardon <thomas_reardon@hotmail.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

diff --git a/misc/tune2fs.c b/misc/tune2fs.c
index 7292ab1..80debe7 100644 (file)
--- a/misc/tune2fs.c
+++ b/misc/tune2fs.c
@@ -839,7 +839,7 @@ out:
        return retval;
 }
 
-static void disable_uninit_bg(ext2_filsys fs, __u32 csum_feature_flag)
+static errcode_t disable_uninit_bg(ext2_filsys fs, __u32 csum_feature_flag)
 {
        struct ext2_group_desc *gd;
        dgrp_t i;
@@ -849,14 +849,15 @@ static void disable_uninit_bg(ext2_filsys fs, __u32 csum_feature_flag)
        /* Load bitmaps to ensure that the uninit ones get written out */
        fs->super->s_feature_ro_compat |= csum_feature_flag;
        retval = ext2fs_read_bitmaps(fs);
+       fs->super->s_feature_ro_compat &= ~csum_feature_flag;
        if (retval) {
                com_err("disable_uninit_bg", retval,
                        "while reading bitmaps");
-               return;
+               request_fsck_afterwards(fs);
+               return retval;
        }
        ext2fs_mark_ib_dirty(fs);
        ext2fs_mark_bb_dirty(fs);
-       fs->super->s_feature_ro_compat &= ~csum_feature_flag;
 
        /* If we're only turning off uninit_bg, zero the inodes */
        if (csum_feature_flag == EXT4_FEATURE_RO_COMPAT_GDT_CSUM) {
@@ -865,6 +866,7 @@ static void disable_uninit_bg(ext2_filsys fs, __u32 csum_feature_flag)
                        com_err("disable_uninit_bg", retval,
                                "while zeroing unused inodes");
                        request_fsck_afterwards(fs);
+                       return retval;
                }
        }
 
@@ -895,6 +897,8 @@ static void disable_uninit_bg(ext2_filsys fs, __u32 csum_feature_flag)
        }
        fs->flags &= ~EXT2_FLAG_SUPER_ONLY;
        ext2fs_mark_super_dirty(fs);
+
+       return 0;
 }
 
 /*
@@ -906,6 +910,7 @@ static int update_feature_set(ext2_filsys fs, char *features)
        __u32           old_features[3];
        int             type_err;
        unsigned int    mask_err;
+       errcode_t       err;
 
 #define FEATURE_ON(type, mask) (!(old_features[(type)] & (mask)) && \
                                ((&sb->s_feature_compat)[(type)] & (mask)))
@@ -1114,10 +1119,12 @@ mmp_error:
                 * uninit_bg, rewrite group desc.
                 */
                if (!(fs->super->s_feature_ro_compat &
-                     EXT4_FEATURE_RO_COMPAT_GDT_CSUM))
-                       disable_uninit_bg(fs,
-                               EXT4_FEATURE_RO_COMPAT_METADATA_CSUM);
-               else
+                     EXT4_FEATURE_RO_COMPAT_GDT_CSUM)) {
+                       err = disable_uninit_bg(fs,
+                                       EXT4_FEATURE_RO_COMPAT_METADATA_CSUM);
+                       if (err)
+                               return 1;
+               } else
                        /*
                         * metadata_csum previously provided uninit_bg, so if
                         * we're also setting the uninit_bg feature bit,
@@ -1140,9 +1147,12 @@ mmp_error:
        }
 
        if (FEATURE_OFF(E2P_FEATURE_RO_INCOMPAT,
-                       EXT4_FEATURE_RO_COMPAT_GDT_CSUM))
-               disable_uninit_bg(fs,
+                       EXT4_FEATURE_RO_COMPAT_GDT_CSUM)) {
+               err = disable_uninit_bg(fs,
                                EXT4_FEATURE_RO_COMPAT_GDT_CSUM);
+               if (err)
+                       return 1;
+       }
 
        if (FEATURE_ON(E2P_FEATURE_RO_INCOMPAT,
                                EXT4_FEATURE_RO_COMPAT_QUOTA)) {