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| author | Theodore Ts'o <tytso@mit.edu> | 2014-12-26 23:58:21 -0500 |
|---|---|---|
| committer | Theodore Ts'o <tytso@mit.edu> | 2014-12-26 23:58:21 -0500 |
| commit | 011fa99404bea3f5d897c4983f6bd51170e3b18f (patch) | |
| tree | 09233f55cd3aa55cf779f684cd1968cc36a08437 | |
| parent | 50db71abc529c48b21f4c3034d3cff27cfb25795 (diff) | |
| download | linux-011fa99404bea3f5d897c4983f6bd51170e3b18f.tar.gz linux-011fa99404bea3f5d897c4983f6bd51170e3b18f.tar.bz2 linux-011fa99404bea3f5d897c4983f6bd51170e3b18f.zip | |
ext4: prevent online resize with backup superblock
Prevent BUG or corrupted file systems after the following:
mkfs.ext4 /dev/vdc 100M
mount -t ext4 -o sb=40961 /dev/vdc /vdc
resize2fs /dev/vdc
We previously prevented online resizing using the old resize ioctl.
Move the code to ext4_resize_begin(), so the check applies for all of
the resize ioctl's.
Reported-by: Maxim Malkov <malkov@ispras.ru>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
| -rw-r--r-- | fs/ext4/resize.c | 24 |
1 files changed, 12 insertions, 12 deletions
diff --git a/fs/ext4/resize.c b/fs/ext4/resize.c index bf76f405a5f9..8a8ec6293b19 100644 --- a/fs/ext4/resize.c +++ b/fs/ext4/resize.c @@ -24,6 +24,18 @@ int ext4_resize_begin(struct super_block *sb) return -EPERM; /* + * If we are not using the primary superblock/GDT copy don't resize, + * because the user tools have no way of handling this. Probably a + * bad time to do it anyways. + */ + if (EXT4_SB(sb)->s_sbh->b_blocknr != + le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block)) { + ext4_warning(sb, "won't resize using backup superblock at %llu", + (unsigned long long)EXT4_SB(sb)->s_sbh->b_blocknr); + return -EPERM; + } + + /* * We are not allowed to do online-resizing on a filesystem mounted * with error, because it can destroy the filesystem easily. */ @@ -758,18 +770,6 @@ static int add_new_gdb(handle_t *handle, struct inode *inode, "EXT4-fs: ext4_add_new_gdb: adding group block %lu\n", gdb_num); - /* - * If we are not using the primary superblock/GDT copy don't resize, - * because the user tools have no way of handling this. Probably a - * bad time to do it anyways. - */ - if (EXT4_SB(sb)->s_sbh->b_blocknr != - le32_to_cpu(EXT4_SB(sb)->s_es->s_first_data_block)) { - ext4_warning(sb, "won't resize using backup superblock at %llu", - (unsigned long long)EXT4_SB(sb)->s_sbh->b_blocknr); - return -EPERM; - } - gdb_bh = sb_bread(sb, gdblock); if (!gdb_bh) return -EIO; |