From 0f2f87d51aebcf71a709b52f661d681594c7dffa Mon Sep 17 00:00:00 2001 From: Zhang Yi Date: Wed, 8 Sep 2021 20:08:50 +0800 Subject: ext4: prevent partial update of the extent blocks 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 Reviewed-by: Theodore Ts'o Link: https://lore.kernel.org/r/20210908120850.4012324-4-yi.zhang@huawei.com Signed-off-by: Theodore Ts'o --- fs/ext4/extents.c | 19 ++++++++++++++++--- 1 file changed, 16 insertions(+), 3 deletions(-) (limited to 'fs/ext4') diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c index f6a902de7f41..09f56e04f4b2 100644 --- a/fs/ext4/extents.c +++ b/fs/ext4/extents.c @@ -136,15 +136,25 @@ int ext4_datasem_ensure_credits(handle_t *handle, struct inode *inode, 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, inode->i_sb, - path->p_bh, EXT4_JTR_NONE); + err = ext4_journal_get_write_access(handle, inode->i_sb, + path->p_bh, EXT4_JTR_NONE); + /* + * 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; } /* @@ -165,6 +175,9 @@ static int __ext4_ext_dirty(const char *where, unsigned int line, /* 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); -- cgit v1.2.3