Commit 1b364dc9 authored by Andreas Dilger's avatar Andreas Dilger Committed by Sasha Levin

xattr: Option to disable meta-data block cache

mbcache provides absolutely no value for Lustre xattrs (because
they are unique and cannot be shared between files) and as we can
see it has a noticable overhead in some cases. In the past there
was a CONFIG_MBCACHE option that would allow it to be disabled,
but this was removed in newer kernels, so we will need to patch
ldiskfs to fix this.

References: <https://bugzilla.kernel.org/show_bug.cgi?id=107301>
References: <https://git.hpdd.intel.com/fs/lustre-release.git/blob_plain/HEAD:/ldiskfs/kernel_patches/patches/rhel7/ext4-disable-mb-cache.patch>
References: CVE-2015-8952

On 13.12.2016 at 15:58 Ben Hutchings wrote:
> I decided not to apply this as it's a userland ABI extension that we
> would then need to carry indefinitely.
Signed-off-by: default avatarPhilipp Hahn <hahn@univention.de>
Signed-off-by: default avatarSasha Levin <alexander.levin@verizon.com>
parent 9a66bc6e
......@@ -1008,6 +1008,7 @@ struct ext4_inode_info {
/*
* Mount flags set via mount options or defaults
*/
#define EXT4_MOUNT_NO_MBCACHE 0x00001 /* Disable mbcache */
#define EXT4_MOUNT_GRPID 0x00004 /* Create files with directory's group */
#define EXT4_MOUNT_DEBUG 0x00008 /* Some debugging messages */
#define EXT4_MOUNT_ERRORS_CONT 0x00010 /* Continue on errors */
......
......@@ -1144,6 +1144,7 @@ enum {
Opt_nomblk_io_submit, Opt_block_validity, Opt_noblock_validity,
Opt_inode_readahead_blks, Opt_journal_ioprio,
Opt_dioread_nolock, Opt_dioread_lock,
Opt_no_mbcache,
Opt_discard, Opt_nodiscard, Opt_init_itable, Opt_noinit_itable,
Opt_max_dir_size_kb, Opt_nojournal_checksum,
};
......@@ -1222,6 +1223,7 @@ static const match_table_t tokens = {
{Opt_discard, "discard"},
{Opt_nodiscard, "nodiscard"},
{Opt_init_itable, "init_itable=%u"},
{Opt_no_mbcache, "no_mbcache"},
{Opt_init_itable, "init_itable"},
{Opt_noinit_itable, "noinit_itable"},
{Opt_max_dir_size_kb, "max_dir_size_kb=%u"},
......@@ -1385,6 +1387,7 @@ static const struct mount_opts {
{Opt_noauto_da_alloc, EXT4_MOUNT_NO_AUTO_DA_ALLOC, MOPT_SET},
{Opt_auto_da_alloc, EXT4_MOUNT_NO_AUTO_DA_ALLOC, MOPT_CLEAR},
{Opt_noinit_itable, EXT4_MOUNT_INIT_INODE_TABLE, MOPT_CLEAR},
{Opt_no_mbcache, EXT4_MOUNT_NO_MBCACHE, MOPT_SET},
{Opt_commit, 0, MOPT_GTE0},
{Opt_max_batch_time, 0, MOPT_GTE0},
{Opt_min_batch_time, 0, MOPT_GTE0},
......
......@@ -80,7 +80,7 @@
# define ea_bdebug(bh, fmt, ...) no_printk(fmt, ##__VA_ARGS__)
#endif
static void ext4_xattr_cache_insert(struct mb_cache *, struct buffer_head *);
static void ext4_xattr_cache_insert(struct inode *, struct buffer_head *);
static struct buffer_head *ext4_xattr_cache_find(struct inode *,
struct ext4_xattr_header *,
struct mb_cache_entry **);
......@@ -278,7 +278,6 @@ ext4_xattr_block_get(struct inode *inode, int name_index, const char *name,
struct ext4_xattr_entry *entry;
size_t size;
int error;
struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode);
ea_idebug(inode, "name=%d.%s, buffer=%p, buffer_size=%ld",
name_index, name, buffer, (long)buffer_size);
......@@ -300,7 +299,7 @@ ext4_xattr_block_get(struct inode *inode, int name_index, const char *name,
error = -EIO;
goto cleanup;
}
ext4_xattr_cache_insert(ext4_mb_cache, bh);
ext4_xattr_cache_insert(inode, bh);
entry = BFIRST(bh);
error = ext4_xattr_find_entry(&entry, name_index, name, bh->b_size, 1);
if (error == -EIO)
......@@ -426,7 +425,6 @@ ext4_xattr_block_list(struct dentry *dentry, char *buffer, size_t buffer_size)
struct inode *inode = d_inode(dentry);
struct buffer_head *bh = NULL;
int error;
struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode);
ea_idebug(inode, "buffer=%p, buffer_size=%ld",
buffer, (long)buffer_size);
......@@ -448,7 +446,7 @@ ext4_xattr_block_list(struct dentry *dentry, char *buffer, size_t buffer_size)
error = -EIO;
goto cleanup;
}
ext4_xattr_cache_insert(ext4_mb_cache, bh);
ext4_xattr_cache_insert(inode, bh);
error = ext4_xattr_list_entries(dentry, BFIRST(bh), buffer, buffer_size);
cleanup:
......@@ -547,6 +545,7 @@ ext4_xattr_release_block(handle_t *handle, struct inode *inode,
int error = 0;
struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode);
if (!test_opt(inode->i_sb, NO_MBCACHE))
ce = mb_cache_entry_get(ext4_mb_cache, bh->b_bdev, bh->b_blocknr);
BUFFER_TRACE(bh, "get_write_access");
error = ext4_journal_get_write_access(handle, bh);
......@@ -788,6 +787,7 @@ ext4_xattr_block_set(handle_t *handle, struct inode *inode,
if (i->value && i->value_len > sb->s_blocksize)
return -ENOSPC;
if (s->base) {
if (!test_opt(inode->i_sb, NO_MBCACHE))
ce = mb_cache_entry_get(ext4_mb_cache, bs->bh->b_bdev,
bs->bh->b_blocknr);
BUFFER_TRACE(bs->bh, "get_write_access");
......@@ -807,7 +807,7 @@ ext4_xattr_block_set(handle_t *handle, struct inode *inode,
if (!IS_LAST_ENTRY(s->first))
ext4_xattr_rehash(header(s->base),
s->here);
ext4_xattr_cache_insert(ext4_mb_cache,
ext4_xattr_cache_insert(inode,
bs->bh);
}
unlock_buffer(bs->bh);
......@@ -892,6 +892,7 @@ ext4_xattr_block_set(handle_t *handle, struct inode *inode,
if (error)
goto cleanup_dquot;
}
if (ce)
mb_cache_entry_release(ce);
ce = NULL;
} else if (bs->bh && s->base == bs->bh->b_data) {
......@@ -939,7 +940,7 @@ ext4_xattr_block_set(handle_t *handle, struct inode *inode,
memcpy(new_bh->b_data, s->base, new_bh->b_size);
set_buffer_uptodate(new_bh);
unlock_buffer(new_bh);
ext4_xattr_cache_insert(ext4_mb_cache, new_bh);
ext4_xattr_cache_insert(inode, new_bh);
error = ext4_handle_dirty_xattr_block(handle,
inode, new_bh);
if (error)
......@@ -1529,12 +1530,17 @@ ext4_xattr_put_super(struct super_block *sb)
* Returns 0, or a negative error number on failure.
*/
static void
ext4_xattr_cache_insert(struct mb_cache *ext4_mb_cache, struct buffer_head *bh)
ext4_xattr_cache_insert(struct inode *inode, struct buffer_head *bh)
{
struct super_block *sb = inode->i_sb;
struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode);
__u32 hash = le32_to_cpu(BHDR(bh)->h_hash);
struct mb_cache_entry *ce;
int error;
if (test_opt(sb, NO_MBCACHE))
return;
ce = mb_cache_entry_alloc(ext4_mb_cache, GFP_NOFS);
if (!ce) {
ea_bdebug(bh, "out of memory");
......@@ -1609,6 +1615,8 @@ ext4_xattr_cache_find(struct inode *inode, struct ext4_xattr_header *header,
struct mb_cache_entry *ce;
struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode);
if (test_opt(inode->i_sb, NO_MBCACHE))
return NULL;
if (!header->h_hash)
return NULL; /* never share */
ea_idebug(inode, "looking for cached blocks [%x]", (int)hash);
......
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