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-3.10.0-123.13.2.el7.x86_64/fs/ext4/ext4.h
9 ===================================================================
10 --- linux-3.10.0-123.13.2.el7.x86_64.orig/fs/ext4/ext4.h
11 +++ linux-3.10.0-123.13.2.el7.x86_64/fs/ext4/ext4.h
12 @@ -944,6 +944,7 @@ 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_GRPID 0x00004 /* Create files with directory's group */
18 #define EXT4_MOUNT_DEBUG 0x00008 /* Some debugging messages */
19 #define EXT4_MOUNT_ERRORS_CONT 0x00010 /* Continue on errors */
20 Index: linux-3.10.0-123.13.2.el7.x86_64/fs/ext4/super.c
21 ===================================================================
22 --- linux-3.10.0-123.13.2.el7.x86_64.orig/fs/ext4/super.c
23 +++ linux-3.10.0-123.13.2.el7.x86_64/fs/ext4/super.c
24 @@ -1157,6 +1157,7 @@ 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,
32 @@ -1231,6 +1232,7 @@ 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 @@ -1390,6 +1392,7 @@ 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-3.10.0-123.13.2.el7.x86_64/fs/ext4/xattr.c
49 ===================================================================
50 --- linux-3.10.0-123.13.2.el7.x86_64.orig/fs/ext4/xattr.c
51 +++ linux-3.10.0-123.13.2.el7.x86_64/fs/ext4/xattr.c
53 # define ea_bdebug(bh, fmt, ...) no_printk(fmt, ##__VA_ARGS__)
56 -static void ext4_xattr_cache_insert(struct mb_cache *, struct buffer_head *);
57 +static void _ext4_xattr_cache_insert(struct mb_cache *, struct buffer_head *);
58 static struct buffer_head *ext4_xattr_cache_find(struct inode *,
59 struct ext4_xattr_header *,
60 struct mb_cache_entry **);
61 @@ -401,7 +401,8 @@ bad_block:
62 error = -EFSCORRUPTED;
65 - ext4_xattr_cache_insert(ext4_mb_cache, bh);
66 + if (!test_opt(inode->i_sb, NO_MBCACHE))
67 + _ext4_xattr_cache_insert(ext4_mb_cache, bh);
69 error = ext4_xattr_find_entry(&entry, name_index, name, bh->b_size, 1,
71 @@ -565,7 +566,8 @@ ext4_xattr_block_list(struct dentry *den
72 error = -EFSCORRUPTED;
75 - ext4_xattr_cache_insert(ext4_mb_cache, bh);
76 + if (!test_opt(inode->i_sb, NO_MBCACHE))
77 + _ext4_xattr_cache_insert(ext4_mb_cache, bh);
78 error = ext4_xattr_list_entries(dentry, BFIRST(bh), buffer, buffer_size);
81 @@ -678,7 +680,9 @@ ext4_xattr_release_block(handle_t *handl
82 * This must happen under buffer lock for
83 * ext4_xattr_block_set() to reliably detect freed block
85 - mb_cache_entry_delete_block(ext4_mb_cache, hash, bh->b_blocknr);
86 + if (!test_opt(inode->i_sb, NO_MBCACHE))
87 + mb_cache_entry_delete_block(ext4_mb_cache,
88 + hash, bh->b_blocknr);
91 ext4_free_blocks(handle, inode, bh, 0, 1,
92 @@ -690,9 +694,10 @@ ext4_xattr_release_block(handle_t *handl
95 if (ref == EXT4_XATTR_REFCOUNT_MAX - 1) {
96 - struct mb_cache_entry *ce;
97 + struct mb_cache_entry *ce = NULL;
99 - ce = mb_cache_entry_get(ext4_mb_cache, hash,
100 + if (!test_opt(inode->i_sb, NO_MBCACHE))
101 + ce = mb_cache_entry_get(ext4_mb_cache, hash,
105 @@ -1107,7 +1112,8 @@ ext4_xattr_block_set(handle_t *handle, s
106 * ext4_xattr_block_set() to reliably detect modified
109 - mb_cache_entry_delete_block(ext4_mb_cache, hash,
110 + if (!test_opt(inode->i_sb, NO_MBCACHE))
111 + mb_cache_entry_delete_block(ext4_mb_cache, hash,
113 ea_bdebug(bs->bh, "modifying in-place");
114 error = ext4_xattr_set_entry(i, s, handle, inode);
115 @@ -1115,8 +1121,9 @@ ext4_xattr_block_set(handle_t *handle, s
116 if (!IS_LAST_ENTRY(s->first))
117 ext4_xattr_rehash(header(s->base),
119 - ext4_xattr_cache_insert(ext4_mb_cache,
121 + if (!test_opt(inode->i_sb, NO_MBCACHE))
122 + _ext4_xattr_cache_insert(ext4_mb_cache,
125 unlock_buffer(bs->bh);
126 if (error == -EFSCORRUPTED)
127 @@ -1277,7 +1284,8 @@ getblk_failed:
128 memcpy(new_bh->b_data, s->base, new_bh->b_size);
129 set_buffer_uptodate(new_bh);
130 unlock_buffer(new_bh);
131 - ext4_xattr_cache_insert(ext4_mb_cache, new_bh);
132 + if (!test_opt(inode->i_sb, NO_MBCACHE))
133 + _ext4_xattr_cache_insert(ext4_mb_cache, new_bh);
134 error = ext4_handle_dirty_xattr_block(handle,
137 @@ -2068,7 +2076,7 @@ ext4_xattr_inode_array_free(struct inode
138 * Returns 0, or a negative error number on failure.
141 -ext4_xattr_cache_insert(struct mb_cache *ext4_mb_cache, struct buffer_head *bh)
142 +_ext4_xattr_cache_insert(struct mb_cache *ext4_mb_cache, struct buffer_head *bh)
144 struct ext4_xattr_header *header = BHDR(bh);
145 __u32 hash = le32_to_cpu(header->h_hash);
146 @@ -2140,6 +2148,8 @@ ext4_xattr_cache_find(struct inode *inod
147 struct mb_cache_entry *ce;
148 struct mb_cache *ext4_mb_cache = EXT4_GET_MB_CACHE(inode);
150 + if (test_opt(inode->i_sb, NO_MBCACHE))
153 return NULL; /* never share */
154 ea_idebug(inode, "looking for cached blocks [%x]", (int)hash);