From 1f60fbe7274918adb8db2f616e321890730ab7e3 Mon Sep 17 00:00:00 2001 From: Theodore Ts'o Date: Sat, 23 Apr 2016 22:50:07 -0400 Subject: ext4: allow readdir()'s of large empty directories to be interrupted If a directory has a large number of empty blocks, iterating over all of them can take a long time, leading to scheduler warnings and users getting irritated when they can't kill a process in the middle of one of these long-running readdir operations. Fix this by adding checks to ext4_readdir() and ext4_htree_fill_tree(). This was reverted earlier due to a typo in the original commit where I experimented with using signal_pending() instead of fatal_signal_pending(). The test was in the wrong place if we were going to return signal_pending() since we would end up returning duplicant entries. See 9f2394c9be47 for a more detailed explanation. Added fix as suggested by Linus to check for signal_pending() in in the filldir() functions. Reported-by: Benjamin LaHaise Google-Bug-Id: 27880676 Signed-off-by: Theodore Ts'o --- fs/compat.c | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'fs/compat.c') diff --git a/fs/compat.c b/fs/compat.c index a71936a3f4cb..f940cb20562f 100644 --- a/fs/compat.c +++ b/fs/compat.c @@ -936,6 +936,8 @@ static int compat_filldir(struct dir_context *ctx, const char *name, int namlen, } dirent = buf->previous; if (dirent) { + if (signal_pending(current)) + return -EINTR; if (__put_user(offset, &dirent->d_off)) goto efault; } @@ -1020,6 +1022,8 @@ static int compat_filldir64(struct dir_context *ctx, const char *name, dirent = buf->previous; if (dirent) { + if (signal_pending(current)) + return -EINTR; if (__put_user_unaligned(offset, &dirent->d_off)) goto efault; } -- cgit v1.2.3-59-g8ed1b