CVE-2022-50286

In the Linux kernel, the following vulnerability has been resolved:

ext4: fix delayed allocation bug in ext4_clu_mapped for bigalloc + inline

When converting files with inline data to extents, delayed allocations

made on a file system created with both the bigalloc and inline options

can result in invalid extent status cache content, incorrect reserved

cluster counts, kernel memory leaks, and potential kernel panics.

With bigalloc, the code that determines whether a block must be

delayed allocated searches the extent tree to see if that block maps

to a previously allocated cluster. If not, the block is delayed

allocated, and otherwise, it isn't. However, if the inline option is

also used, and if the file containing the block is marked as able to

store data inline, there isn't a valid extent tree associated with

the file. The current code in ext4_clu_mapped() calls

ext4_find_extent() to search the non-existent tree for a previously

allocated cluster anyway, which typically finds nothing, as desired.

However, a side effect of the search can be to cache invalid content

from the non-existent tree (garbage) in the extent status tree,

including bogus entries in the pending reservation tree.

To fix this, avoid searching the extent tree when allocating blocks

for bigalloc + inline files that are being converted from inline to

extent mapped.