From: Zhang Yi yi.zhang@huawei.com
commit 0f2f87d51aebcf71a709b52f661d681594c7dffa upstream.
In the most error path of current extents updating operations are not roll back partial updates properly when some bad things happens(.e.g in ext4_ext_insert_extent()). So we may get an inconsistent extents tree if journal has been aborted due to IO error, which may probability lead to BUGON later when we accessing these extent entries in errors=continue mode. This patch drop extent buffer's verify flag before updatng the contents in ext4_ext_get_access(), and reset it after updating in __ext4_ext_dirty(). After this patch we could force to check the extent buffer if extents tree updating was break off, make sure the extents are consistent.
Signed-off-by: Zhang Yi yi.zhang@huawei.com Reviewed-by: Theodore Ts'o tytso@mit.edu Link: https://lore.kernel.org/r/20210908120850.4012324-4-yi.zhang@huawei.com Signed-off-by: Theodore Ts'o tytso@mit.edu Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- fs/ext4/extents.c | 17 +++++++++++++++-- 1 file changed, 15 insertions(+), 2 deletions(-)
--- a/fs/ext4/extents.c +++ b/fs/ext4/extents.c @@ -136,14 +136,24 @@ int ext4_datasem_ensure_credits(handle_t static int ext4_ext_get_access(handle_t *handle, struct inode *inode, struct ext4_ext_path *path) { + int err = 0; + if (path->p_bh) { /* path points to block */ BUFFER_TRACE(path->p_bh, "get_write_access"); - return ext4_journal_get_write_access(handle, path->p_bh); + err = ext4_journal_get_write_access(handle, path->p_bh); + /* + * The extent buffer's verified bit will be set again in + * __ext4_ext_dirty(). We could leave an inconsistent + * buffer if the extents updating procudure break off du + * to some error happens, force to check it again. + */ + if (!err) + clear_buffer_verified(path->p_bh); } /* path points to leaf/index in inode body */ /* we use in-core data, no need to protect them */ - return 0; + return err; }
/* @@ -164,6 +174,9 @@ static int __ext4_ext_dirty(const char * /* path points to block */ err = __ext4_handle_dirty_metadata(where, line, handle, inode, path->p_bh); + /* Extents updating done, re-set verified flag */ + if (!err) + set_buffer_verified(path->p_bh); } else { /* path points to leaf/index in inode body */ err = ext4_mark_inode_dirty(handle, inode);