1 mbcache provides absolutely no value for Lustre xattrs (because
2 they are unique and cannot be shared between files) and as we can
3 see it has a noticable overhead in some cases. In the past there
4 was a CONFIG_MBCACHE option that would allow it to be disabled,
5 but this was removed in newer kernels, so we will need to patch
8 Index: linux-stage/fs/ext4/ext4.h
9 ===================================================================
10 --- linux-stage.orig/fs/ext4/ext4.h
11 +++ linux-stage/fs/ext4/ext4.h
12 @@ -963,6 +963,7 @@ struct ext4_inode_info {
14 * Mount flags set via mount options or defaults
16 +#define EXT4_MOUNT_NO_MBCACHE 0x00001 /* Disable mbcache */
17 #define EXT4_MOUNT_DIRDATA 0x00002 /* Data in directory entries*/
18 #define EXT4_MOUNT_GRPID 0x00004 /* Create files with directory's group */
19 #define EXT4_MOUNT_DEBUG 0x00008 /* Some debugging messages */
20 Index: linux-stage/fs/ext4/super.c
21 ===================================================================
22 --- linux-stage.orig/fs/ext4/super.c
23 +++ linux-stage/fs/ext4/super.c
24 @@ -1161,6 +1161,7 @@ enum {
25 Opt_nomblk_io_submit, Opt_block_validity, Opt_noblock_validity,
26 Opt_inode_readahead_blks, Opt_journal_ioprio,
27 Opt_dioread_nolock, Opt_dioread_lock,
29 Opt_discard, Opt_nodiscard, Opt_init_itable, Opt_noinit_itable,
30 Opt_max_dir_size_kb, Opt_nojournal_checksum,
32 @@ -1238,6 +1239,7 @@ static const match_table_t tokens = {
33 {Opt_discard, "discard"},
34 {Opt_nodiscard, "nodiscard"},
35 {Opt_init_itable, "init_itable=%u"},
36 + {Opt_no_mbcache, "no_mbcache"},
37 {Opt_init_itable, "init_itable"},
38 {Opt_noinit_itable, "noinit_itable"},
39 {Opt_max_dir_size_kb, "max_dir_size_kb=%u"},
40 @@ -1400,6 +1402,7 @@ static const struct mount_opts {
41 {Opt_noauto_da_alloc, EXT4_MOUNT_NO_AUTO_DA_ALLOC, MOPT_SET},
42 {Opt_auto_da_alloc, EXT4_MOUNT_NO_AUTO_DA_ALLOC, MOPT_CLEAR},
43 {Opt_noinit_itable, EXT4_MOUNT_INIT_INODE_TABLE, MOPT_CLEAR},
44 + {Opt_no_mbcache, EXT4_MOUNT_NO_MBCACHE, MOPT_SET},
45 {Opt_commit, 0, MOPT_GTE0},
46 {Opt_max_batch_time, 0, MOPT_GTE0},
47 {Opt_min_batch_time, 0, MOPT_GTE0},
48 Index: linux-stage/fs/ext4/xattr.c
49 ===================================================================
50 --- linux-stage.orig/fs/ext4/xattr.c
51 +++ linux-stage/fs/ext4/xattr.c
53 # define ea_bdebug(bh, fmt, ...) no_printk(fmt, ##__VA_ARGS__)
56 -static void ext4_xattr_cache_insert(struct buffer_head *);
57 +static void ext4_xattr_cache_insert(struct super_block *,
58 + struct buffer_head *);
59 static struct buffer_head *ext4_xattr_cache_find(struct inode *,
60 struct ext4_xattr_header *,
61 struct mb_cache_entry **);
62 @@ -405,7 +406,7 @@ bad_block:
66 - ext4_xattr_cache_insert(bh);
67 + ext4_xattr_cache_insert(inode->i_sb, bh);
69 error = ext4_xattr_find_entry(&entry, name_index, name, bh->b_size, 1,
71 @@ -569,7 +570,7 @@ ext4_xattr_block_list(struct dentry *den
75 - ext4_xattr_cache_insert(bh);
76 + ext4_xattr_cache_insert(inode->i_sb, bh);
77 error = ext4_xattr_list_entries(dentry, BFIRST(bh), buffer, buffer_size);
80 @@ -667,7 +668,9 @@ ext4_xattr_release_block(handle_t *handl
81 struct mb_cache_entry *ce = NULL;
84 - ce = mb_cache_entry_get(ext4_xattr_cache, bh->b_bdev, bh->b_blocknr);
85 + if (!test_opt(inode->i_sb, NO_MBCACHE))
86 + ce = mb_cache_entry_get(ext4_xattr_cache, bh->b_bdev,
88 BUFFER_TRACE(bh, "get_write_access");
89 error = ext4_journal_get_write_access(handle, bh);
91 @@ -1082,8 +1085,10 @@ ext4_xattr_block_set(handle_t *handle, s
92 #define header(x) ((struct ext4_xattr_header *)(x))
95 - ce = mb_cache_entry_get(ext4_xattr_cache, bs->bh->b_bdev,
97 + if (!test_opt(inode->i_sb, NO_MBCACHE))
98 + ce = mb_cache_entry_get(ext4_xattr_cache,
100 + bs->bh->b_blocknr);
101 BUFFER_TRACE(bs->bh, "get_write_access");
102 error = ext4_journal_get_write_access(handle, bs->bh);
104 @@ -1101,7 +1106,7 @@ ext4_xattr_block_set(handle_t *handle, s
105 if (!IS_LAST_ENTRY(s->first))
106 ext4_xattr_rehash(header(s->base),
108 - ext4_xattr_cache_insert(bs->bh);
109 + ext4_xattr_cache_insert(sb, bs->bh);
111 unlock_buffer(bs->bh);
113 @@ -1185,7 +1190,8 @@ inserted:
117 - mb_cache_entry_release(ce);
119 + mb_cache_entry_release(ce);
121 } else if (bs->bh && s->base == bs->bh->b_data) {
122 /* We were modifying this block in-place. */
123 @@ -1238,7 +1244,7 @@ getblk_failed:
124 memcpy(new_bh->b_data, s->base, new_bh->b_size);
125 set_buffer_uptodate(new_bh);
126 unlock_buffer(new_bh);
127 - ext4_xattr_cache_insert(new_bh);
128 + ext4_xattr_cache_insert(sb, new_bh);
129 error = ext4_handle_dirty_xattr_block(handle,
132 @@ -2022,12 +2028,15 @@ ext4_xattr_put_super(struct super_block
133 * Returns 0, or a negative error number on failure.
136 -ext4_xattr_cache_insert(struct buffer_head *bh)
137 +ext4_xattr_cache_insert(struct super_block *sb, struct buffer_head *bh)
139 __u32 hash = le32_to_cpu(BHDR(bh)->h_hash);
140 struct mb_cache_entry *ce;
143 + if (test_opt(sb, NO_MBCACHE))
146 ce = mb_cache_entry_alloc(ext4_xattr_cache, GFP_NOFS);
148 ea_bdebug(bh, "out of memory");
149 @@ -2100,6 +2109,8 @@ ext4_xattr_cache_find(struct inode *inod
150 __u32 hash = le32_to_cpu(header->h_hash);
151 struct mb_cache_entry *ce;
153 + if (test_opt(inode->i_sb, NO_MBCACHE))
156 return NULL; /* never share */
157 ea_idebug(inode, "looking for cached blocks [%x]", (int)hash);