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authorHugh Dickins <hughd@google.com>2021-05-05 04:32:57 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2021-05-05 21:27:20 +0300
commit786b31121a2ce4309a81a7f36d63f02ca588839e (patch)
tree06e57daf451657c0a621521303bdbce732b58969 /fs
parent8bc3c481b3d0dcef2cf8e1b7c6b780af6725f7e3 (diff)
downloadlinux-786b31121a2ce4309a81a7f36d63f02ca588839e.tar.xz
mm: remove nrexceptional from inode: remove BUG_ON
clear_inode()'s BUG_ON(!mapping_empty(&inode->i_data)) is unsafe: we know of two ways in which nodes can and do (on rare occasions) get left behind. Until those are fixed, do not BUG_ON() nor even WARN_ON(). Yes, this will then leak those nodes (or the next user of the struct inode may use them); but this has been happening for years, and the new BUG_ON(!mapping_empty) was only guilty of revealing that. A proper fix will follow, but no hurry. Link: https://lkml.kernel.org/r/alpine.LSU.2.11.2104292229380.16080@eggly.anvils Signed-off-by: Hugh Dickins <hughd@google.com> Cc: Matthew Wilcox <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs')
-rw-r--r--fs/inode.c9
1 files changed, 8 insertions, 1 deletions
diff --git a/fs/inode.c b/fs/inode.c
index af48d1b722f0..c93500d84264 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -529,7 +529,14 @@ void clear_inode(struct inode *inode)
*/
xa_lock_irq(&inode->i_data.i_pages);
BUG_ON(inode->i_data.nrpages);
- BUG_ON(!mapping_empty(&inode->i_data));
+ /*
+ * Almost always, mapping_empty(&inode->i_data) here; but there are
+ * two known and long-standing ways in which nodes may get left behind
+ * (when deep radix-tree node allocation failed partway; or when THP
+ * collapse_file() failed). Until those two known cases are cleaned up,
+ * or a cleanup function is called here, do not BUG_ON(!mapping_empty),
+ * nor even WARN_ON(!mapping_empty).
+ */
xa_unlock_irq(&inode->i_data.i_pages);
BUG_ON(!list_empty(&inode->i_data.private_list));
BUG_ON(!(inode->i_state & I_FREEING));