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authorTheodore Ts'o <tytso@mit.edu>2016-03-31 04:36:24 +0200
committerTheodore Ts'o <tytso@mit.edu>2016-03-31 04:36:24 +0200
commit1028b55bafb7611dda1d8fed2aeca16a436b7dff (patch)
treec6881992855b87775897afe3712e6c72811856a0 /fs/ext4
parentbtrfs: fix crash/invalid memory access on fsync when using overlayfs (diff)
downloadlinux-1028b55bafb7611dda1d8fed2aeca16a436b7dff.tar.xz
linux-1028b55bafb7611dda1d8fed2aeca16a436b7dff.zip
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(). Reported-by: Benjamin LaHaise <bcrl@kvack.org> Google-Bug-Id: 27880676 Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Diffstat (limited to 'fs/ext4')
-rw-r--r--fs/ext4/dir.c5
-rw-r--r--fs/ext4/namei.c5
2 files changed, 10 insertions, 0 deletions
diff --git a/fs/ext4/dir.c b/fs/ext4/dir.c
index 33f5e2a50cf8..ebfcb8999db2 100644
--- a/fs/ext4/dir.c
+++ b/fs/ext4/dir.c
@@ -150,6 +150,11 @@ static int ext4_readdir(struct file *file, struct dir_context *ctx)
while (ctx->pos < inode->i_size) {
struct ext4_map_blocks map;
+ if (fatal_signal_pending(current)) {
+ err = -ERESTARTSYS;
+ goto errout;
+ }
+ cond_resched();
map.m_lblk = ctx->pos >> EXT4_BLOCK_SIZE_BITS(sb);
map.m_len = 1;
err = ext4_map_blocks(NULL, inode, &map, 0);
diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c
index 48e4b8907826..db98f89f737f 100644
--- a/fs/ext4/namei.c
+++ b/fs/ext4/namei.c
@@ -1107,6 +1107,11 @@ int ext4_htree_fill_tree(struct file *dir_file, __u32 start_hash,
}
while (1) {
+ if (signal_pending(current)) {
+ err = -ERESTARTSYS;
+ goto errout;
+ }
+ cond_resched();
block = dx_get_block(frame->at);
ret = htree_dirblock_to_tree(dir_file, dir, block, &hinfo,
start_hash, start_minor_hash);