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authorTheodore Ts'o <tytso@mit.edu>2016-04-24 05:50:07 +0300
committerTheodore Ts'o <tytso@mit.edu>2016-04-24 05:50:07 +0300
commit1f60fbe7274918adb8db2f616e321890730ab7e3 (patch)
tree4e41c7a0fd5204cad9e651baa23207bf4dafe256 /fs/compat.c
parentc3b46c73264b03000d1e18b22f5caf63332547c9 (diff)
downloadlinux-1f60fbe7274918adb8db2f616e321890730ab7e3.tar.xz
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 <bcrl@kvack.org> Google-Bug-Id: 27880676 Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Diffstat (limited to 'fs/compat.c')
-rw-r--r--fs/compat.c4
1 files changed, 4 insertions, 0 deletions
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;
}