diff options
author | Theodore Ts'o <tytso@mit.edu> | 2012-08-17 09:48:17 -0400 |
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committer | Theodore Ts'o <tytso@mit.edu> | 2012-08-17 09:48:17 -0400 |
commit | df981d03eeff7971ac7e6ff37000bfa702327ef1 (patch) | |
tree | 4e944139b9e45c4af910c517b57f2d9bc7c81a1a /fs/ext4/namei.c | |
parent | 01fc48e8929e45e67527200017cff4e74e4ba054 (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/namei.c')
-rw-r--r-- | fs/ext4/namei.c | 7 |
1 files changed, 7 insertions, 0 deletions
diff --git a/fs/ext4/namei.c b/fs/ext4/namei.c index 2a42cc04466..7450ff01c3c 100644 --- a/fs/ext4/namei.c +++ b/fs/ext4/namei.c @@ -55,6 +55,13 @@ static struct buffer_head *ext4_append(handle_t *handle, { struct buffer_head *bh; + if (unlikely(EXT4_SB(inode->i_sb)->s_max_dir_size_kb && + ((inode->i_size >> 10) >= + EXT4_SB(inode->i_sb)->s_max_dir_size_kb))) { + *err = -ENOSPC; + return NULL; + } + *block = inode->i_size >> inode->i_sb->s_blocksize_bits; bh = ext4_bread(handle, inode, *block, 1, err); |