On Mon, 20 Jun 2011, Jiaying Zhang wrote: > We have hit the same BUG_ON as described in > https://bugzilla.kernel.org/show_bug.cgi?id=31222 > on some of our servers that have disk failures or corrupted inodes. After > looking at the code, I think the problem is that we are not freeing inode's > preallocation list when check_eofblocks_fl fails in ext4_ext_map_blocks(), > which leaves the inode's preallocation list in an inconsistent state. > > Below is a proposed patch to fix the bug. I have tested it by manually > inserting a random failure in check_eofblocks_fl() and run a test that > creates and uses an inode's preallocated blocks. Without the fix, the kernel > crashes after a few runs. With the fix, no crash is observed. > > ext4: free allocated and pre-allocated blocks when check_eofblocks_fl fails > > Upon corrupted inode or disk failures, we may fail after we already allocate > some blocks from the inode or take some blocks from the inode's preallocation > list, but before we successfully insert the corresponding extent to the extent > tree. In this case, we should free any allocated blocks and discard the inode's > preallocated blocks because the entries in the inode's preallocation list may > be in an inconsistent state. > > Signed-off-by: Jiaying Zhang <jiayingz@xxxxxxxxxx> Hi, the change looks good to me (with one note), but the patch itself is not very well formated, and Ted would have to copy it out. Please use this: ext4: free allocated and pre-allocated blocks when check_eofblocks_fl fails for Subject line and put any comments which should not appear in the commit description after signed-off-by line starting with "--- " line. Or just use git format-patch. > > diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c > index 5199bac..8cf6ec9 100644 > --- a/fs/ext4/extents.c > +++ b/fs/ext4/extents.c > @@ -3596,10 +3596,8 @@ int ext4_ext_map_blocks(handle_t *handle, struct inode *inode, > } > > err = check_eofblocks_fl(handle, inode, map->m_lblk, path, ar.len); > - if (err) > - goto out2; > - > - err = ext4_ext_insert_extent(handle, inode, path, &newex, flags); > + if (!err) > + err = ext4_ext_insert_extent(handle, inode, path, &newex, flags); > if (err) { why not to use: else { > /* free data blocks we just allocated */ > /* not a good idea to call discard here directly, > -- > To unsubscribe from this list: send the line "unsubscribe linux-ext4" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html > Thanks! -Lukas -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
