| Message ID | 20200715131812.7243-3-jack@suse.cz |
|---|---|
| State | Superseded |
| Headers | show |
| Series | ext4: Check journal inode extents more carefully | expand |
On Wed, Jul 15, 2020 at 03:18:10PM +0200, Jan Kara wrote: > Currently, add_system_zone() just silently merges two added system zones > that overlap. However the overlap should not happen and it generally > suggests that some unrelated metadata overlap which indicates the fs is > corrupted. We should have caught such problems earlier (e.g. in > ext4_check_descriptors()) but add this check as another line of defense. > In later patch we also use this for stricter checking of journal inode > extent tree. Looks good, thanks! Reviewed-by: Lukas Czerner <lczerner@redhat.com> > > Signed-off-by: Jan Kara <jack@suse.cz> > --- > fs/ext4/block_validity.c | 36 +++++++++++++----------------------- > 1 file changed, 13 insertions(+), 23 deletions(-) > > diff --git a/fs/ext4/block_validity.c b/fs/ext4/block_validity.c > index 16e9b2fda03a..b394a50ebbe3 100644 > --- a/fs/ext4/block_validity.c > +++ b/fs/ext4/block_validity.c > @@ -68,7 +68,7 @@ static int add_system_zone(struct ext4_system_blocks *system_blks, > ext4_fsblk_t start_blk, > unsigned int count) > { > - struct ext4_system_zone *new_entry = NULL, *entry; > + struct ext4_system_zone *new_entry, *entry; > struct rb_node **n = &system_blks->root.rb_node, *node; > struct rb_node *parent = NULL, *new_node = NULL; > > @@ -79,30 +79,20 @@ static int add_system_zone(struct ext4_system_blocks *system_blks, > n = &(*n)->rb_left; > else if (start_blk >= (entry->start_blk + entry->count)) > n = &(*n)->rb_right; > - else { > - if (start_blk + count > (entry->start_blk + > - entry->count)) > - entry->count = (start_blk + count - > - entry->start_blk); > - new_node = *n; > - new_entry = rb_entry(new_node, struct ext4_system_zone, > - node); > - break; > - } > + else /* Unexpected overlap of system zones. */ > + return -EFSCORRUPTED; > } > > - if (!new_entry) { > - new_entry = kmem_cache_alloc(ext4_system_zone_cachep, > - GFP_KERNEL); > - if (!new_entry) > - return -ENOMEM; > - new_entry->start_blk = start_blk; > - new_entry->count = count; > - new_node = &new_entry->node; > - > - rb_link_node(new_node, parent, n); > - rb_insert_color(new_node, &system_blks->root); > - } > + new_entry = kmem_cache_alloc(ext4_system_zone_cachep, > + GFP_KERNEL); > + if (!new_entry) > + return -ENOMEM; > + new_entry->start_blk = start_blk; > + new_entry->count = count; > + new_node = &new_entry->node; > + > + rb_link_node(new_node, parent, n); > + rb_insert_color(new_node, &system_blks->root); > > /* Can we merge to the left? */ > node = rb_prev(new_node); > -- > 2.16.4 >
diff --git a/fs/ext4/block_validity.c b/fs/ext4/block_validity.c index 16e9b2fda03a..b394a50ebbe3 100644 --- a/fs/ext4/block_validity.c +++ b/fs/ext4/block_validity.c @@ -68,7 +68,7 @@ static int add_system_zone(struct ext4_system_blocks *system_blks, ext4_fsblk_t start_blk, unsigned int count) { - struct ext4_system_zone *new_entry = NULL, *entry; + struct ext4_system_zone *new_entry, *entry; struct rb_node **n = &system_blks->root.rb_node, *node; struct rb_node *parent = NULL, *new_node = NULL; @@ -79,30 +79,20 @@ static int add_system_zone(struct ext4_system_blocks *system_blks, n = &(*n)->rb_left; else if (start_blk >= (entry->start_blk + entry->count)) n = &(*n)->rb_right; - else { - if (start_blk + count > (entry->start_blk + - entry->count)) - entry->count = (start_blk + count - - entry->start_blk); - new_node = *n; - new_entry = rb_entry(new_node, struct ext4_system_zone, - node); - break; - } + else /* Unexpected overlap of system zones. */ + return -EFSCORRUPTED; } - if (!new_entry) { - new_entry = kmem_cache_alloc(ext4_system_zone_cachep, - GFP_KERNEL); - if (!new_entry) - return -ENOMEM; - new_entry->start_blk = start_blk; - new_entry->count = count; - new_node = &new_entry->node; - - rb_link_node(new_node, parent, n); - rb_insert_color(new_node, &system_blks->root); - } + new_entry = kmem_cache_alloc(ext4_system_zone_cachep, + GFP_KERNEL); + if (!new_entry) + return -ENOMEM; + new_entry->start_blk = start_blk; + new_entry->count = count; + new_node = &new_entry->node; + + rb_link_node(new_node, parent, n); + rb_insert_color(new_node, &system_blks->root); /* Can we merge to the left? */ node = rb_prev(new_node);
Currently, add_system_zone() just silently merges two added system zones that overlap. However the overlap should not happen and it generally suggests that some unrelated metadata overlap which indicates the fs is corrupted. We should have caught such problems earlier (e.g. in ext4_check_descriptors()) but add this check as another line of defense. In later patch we also use this for stricter checking of journal inode extent tree. Signed-off-by: Jan Kara <jack@suse.cz> --- fs/ext4/block_validity.c | 36 +++++++++++++----------------------- 1 file changed, 13 insertions(+), 23 deletions(-)