4.18-stable review patch. If anyone has any objections, please let me know.
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From: Vasily Averin vvs@virtuozzo.com
commit eb6984fa4ce2837dcb1f66720a600f31b0bb3739 upstream.
According to Ted Ts'o ext4_getblk() called in ext4_xattr_inode_write() should not return bh = NULL
The only time that bh could be NULL, then, would be in the case of something really going wrong; a programming error elsewhere (perhaps a wild pointer dereference) or I/O error causing on-disk file system corruption (although that would be highly unlikely given that we had *just* allocated the blocks and so the metadata blocks in question probably would still be in the cache).
Fixes: e50e5129f384 ("ext4: xattr-in-inode support") Signed-off-by: Vasily Averin vvs@virtuozzo.com Signed-off-by: Theodore Ts'o tytso@mit.edu Cc: stable@kernel.org # 4.13 Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- fs/ext4/xattr.c | 6 ++++++ 1 file changed, 6 insertions(+)
--- a/fs/ext4/xattr.c +++ b/fs/ext4/xattr.c @@ -1388,6 +1388,12 @@ retry: bh = ext4_getblk(handle, ea_inode, block, 0); if (IS_ERR(bh)) return PTR_ERR(bh); + if (!bh) { + WARN_ON_ONCE(1); + EXT4_ERROR_INODE(ea_inode, + "ext4_getblk() return bh = NULL"); + return -EFSCORRUPTED; + } ret = ext4_journal_get_write_access(handle, bh); if (ret) goto out;