From: Theodore Ts'o tytso@mit.edu
commit 1fd95c05d8f742abfe906620780aee4dbe1a2db0 upstream.
If the call to ext4_map_blocks() fails due to an corrupted file system, ext4_ext_replay_set_iblocks() can get stuck in an infinite loop. This could be reproduced by running generic/526 with a file system that has inline_data and fast_commit enabled. The system will repeatedly log to the console:
EXT4-fs warning (device dm-3): ext4_block_to_path:105: block 1074800922 > max in inode 131076
and the stack that it gets stuck in is:
ext4_block_to_path+0xe3/0x130 ext4_ind_map_blocks+0x93/0x690 ext4_map_blocks+0x100/0x660 skip_hole+0x47/0x70 ext4_ext_replay_set_iblocks+0x223/0x440 ext4_fc_replay_inode+0x29e/0x3b0 ext4_fc_replay+0x278/0x550 do_one_pass+0x646/0xc10 jbd2_journal_recover+0x14a/0x270 jbd2_journal_load+0xc4/0x150 ext4_load_journal+0x1f3/0x490 ext4_fill_super+0x22d4/0x2c00
With this patch, generic/526 still fails, but system is no longer locking up in a tight loop. It's likely the root casue is that fast_commit replay is corrupting file systems with inline_data, and we probably need to add better error handling in the fast commit replay code path beyond what is done here, which essentially just breaks the infinite loop without reporting the to the higher levels of the code.
Fixes: 8016E29F4362 ("ext4: fast commit recovery path") Cc: stable@kernel.org Cc: Harshad Shirwadkar harshadshirwadkar@gmail.com Signed-off-by: Theodore Ts'o tytso@mit.edu Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- fs/ext4/extents.c | 19 ++++++++++++++----- 1 file changed, 14 insertions(+), 5 deletions(-)
--- a/fs/ext4/extents.c +++ b/fs/ext4/extents.c @@ -5907,7 +5907,7 @@ void ext4_ext_replay_shrink_inode(struct }
/* Check if *cur is a hole and if it is, skip it */ -static void skip_hole(struct inode *inode, ext4_lblk_t *cur) +static int skip_hole(struct inode *inode, ext4_lblk_t *cur) { int ret; struct ext4_map_blocks map; @@ -5916,9 +5916,12 @@ static void skip_hole(struct inode *inod map.m_len = ((inode->i_size) >> inode->i_sb->s_blocksize_bits) - *cur;
ret = ext4_map_blocks(NULL, inode, &map, 0); + if (ret < 0) + return ret; if (ret != 0) - return; + return 0; *cur = *cur + map.m_len; + return 0; }
/* Count number of blocks used by this inode and update i_blocks */ @@ -5967,7 +5970,9 @@ int ext4_ext_replay_set_iblocks(struct i * iblocks by total number of differences found. */ cur = 0; - skip_hole(inode, &cur); + ret = skip_hole(inode, &cur); + if (ret < 0) + goto out; path = ext4_find_extent(inode, cur, NULL, 0); if (IS_ERR(path)) goto out; @@ -5986,8 +5991,12 @@ int ext4_ext_replay_set_iblocks(struct i } cur = max(cur + 1, le32_to_cpu(ex->ee_block) + ext4_ext_get_actual_len(ex)); - skip_hole(inode, &cur); - + ret = skip_hole(inode, &cur); + if (ret < 0) { + ext4_ext_drop_refs(path); + kfree(path); + break; + } path2 = ext4_find_extent(inode, cur, NULL, 0); if (IS_ERR(path2)) { ext4_ext_drop_refs(path);