path: root/fs/ext4/ext4.h
diff options
authorTheodore Ts'o <tytso@mit.edu>2012-08-17 09:48:17 -0400
committerTheodore Ts'o <tytso@mit.edu>2012-08-17 09:48:17 -0400
commitdf981d03eeff7971ac7e6ff37000bfa702327ef1 (patch)
tree4e944139b9e45c4af910c517b57f2d9bc7c81a1a /fs/ext4/ext4.h
parent01fc48e8929e45e67527200017cff4e74e4ba054 (diff)
ext4: add max_dir_size_kb mount option
Very large directories can cause significant performance problems, or perhaps even invoke the OOM killer, if the process is running in a highly constrained memory environment (whether it is VM's with a small amount of memory or in a small memory cgroup). So it is useful, in cloud server/data center environments, to be able to set a filesystem-wide cap on the maximum size of a directory, to ensure that directories never get larger than a sane size. We do this via a new mount option, max_dir_size_kb. If there is an attempt to grow the directory larger than max_dir_size_kb, the system call will return ENOSPC instead. Google-Bug-Id: 6863013 Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Diffstat (limited to 'fs/ext4/ext4.h')
1 files changed, 1 insertions, 0 deletions
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index c3411d4ce2d..7c0841ecde6 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -1243,6 +1243,7 @@ struct ext4_sb_info {
unsigned int s_mb_order2_reqs;
unsigned int s_mb_group_prealloc;
unsigned int s_max_writeback_mb_bump;
+ unsigned int s_max_dir_size_kb;
/* where last allocation was done - for stream allocation */
unsigned long s_mb_last_group;
unsigned long s_mb_last_start;