pid namespaces: make proc have multiple superblocks - one for each namespace
[linux-2.6] / fs / gfs2 / trans.c
1 /*
2  * Copyright (C) Sistina Software, Inc.  1997-2003 All rights reserved.
3  * Copyright (C) 2004-2006 Red Hat, Inc.  All rights reserved.
4  *
5  * This copyrighted material is made available to anyone wishing to use,
6  * modify, copy, or redistribute it subject to the terms and conditions
7  * of the GNU General Public License version 2.
8  */
9
10 #include <linux/sched.h>
11 #include <linux/slab.h>
12 #include <linux/spinlock.h>
13 #include <linux/completion.h>
14 #include <linux/buffer_head.h>
15 #include <linux/gfs2_ondisk.h>
16 #include <linux/kallsyms.h>
17 #include <linux/lm_interface.h>
18
19 #include "gfs2.h"
20 #include "incore.h"
21 #include "glock.h"
22 #include "log.h"
23 #include "lops.h"
24 #include "meta_io.h"
25 #include "trans.h"
26 #include "util.h"
27
28 int gfs2_trans_begin(struct gfs2_sbd *sdp, unsigned int blocks,
29                      unsigned int revokes)
30 {
31         struct gfs2_trans *tr;
32         int error;
33
34         BUG_ON(current->journal_info);
35         BUG_ON(blocks == 0 && revokes == 0);
36
37         tr = kzalloc(sizeof(struct gfs2_trans), GFP_NOFS);
38         if (!tr)
39                 return -ENOMEM;
40
41         tr->tr_ip = (unsigned long)__builtin_return_address(0);
42         tr->tr_blocks = blocks;
43         tr->tr_revokes = revokes;
44         tr->tr_reserved = 1;
45         if (blocks)
46                 tr->tr_reserved += 6 + blocks;
47         if (revokes)
48                 tr->tr_reserved += gfs2_struct2blk(sdp, revokes,
49                                                    sizeof(u64));
50         INIT_LIST_HEAD(&tr->tr_list_buf);
51
52         gfs2_holder_init(sdp->sd_trans_gl, LM_ST_SHARED, 0, &tr->tr_t_gh);
53
54         error = gfs2_glock_nq(&tr->tr_t_gh);
55         if (error)
56                 goto fail_holder_uninit;
57
58         if (!test_bit(SDF_JOURNAL_LIVE, &sdp->sd_flags)) {
59                 tr->tr_t_gh.gh_flags |= GL_NOCACHE;
60                 error = -EROFS;
61                 goto fail_gunlock;
62         }
63
64         error = gfs2_log_reserve(sdp, tr->tr_reserved);
65         if (error)
66                 goto fail_gunlock;
67
68         current->journal_info = tr;
69
70         return 0;
71
72 fail_gunlock:
73         gfs2_glock_dq(&tr->tr_t_gh);
74
75 fail_holder_uninit:
76         gfs2_holder_uninit(&tr->tr_t_gh);
77         kfree(tr);
78
79         return error;
80 }
81
82 void gfs2_trans_end(struct gfs2_sbd *sdp)
83 {
84         struct gfs2_trans *tr = current->journal_info;
85
86         BUG_ON(!tr);
87         current->journal_info = NULL;
88
89         if (!tr->tr_touched) {
90                 gfs2_log_release(sdp, tr->tr_reserved);
91                 gfs2_glock_dq(&tr->tr_t_gh);
92                 gfs2_holder_uninit(&tr->tr_t_gh);
93                 kfree(tr);
94                 return;
95         }
96
97         if (gfs2_assert_withdraw(sdp, tr->tr_num_buf <= tr->tr_blocks)) {
98                 fs_err(sdp, "tr_num_buf = %u, tr_blocks = %u ",
99                        tr->tr_num_buf, tr->tr_blocks);
100                 print_symbol(KERN_WARNING "GFS2: Transaction created at: %s\n", tr->tr_ip);
101         }
102         if (gfs2_assert_withdraw(sdp, tr->tr_num_revoke <= tr->tr_revokes)) {
103                 fs_err(sdp, "tr_num_revoke = %u, tr_revokes = %u ",
104                        tr->tr_num_revoke, tr->tr_revokes);
105                 print_symbol(KERN_WARNING "GFS2: Transaction created at: %s\n", tr->tr_ip);
106         }
107
108         gfs2_log_commit(sdp, tr);
109         gfs2_glock_dq(&tr->tr_t_gh);
110         gfs2_holder_uninit(&tr->tr_t_gh);
111         kfree(tr);
112
113         if (sdp->sd_vfs->s_flags & MS_SYNCHRONOUS)
114                 gfs2_log_flush(sdp, NULL);
115 }
116
117 void gfs2_trans_add_gl(struct gfs2_glock *gl)
118 {
119         lops_add(gl->gl_sbd, &gl->gl_le);
120 }
121
122 /**
123  * gfs2_trans_add_bh - Add a to-be-modified buffer to the current transaction
124  * @gl: the glock the buffer belongs to
125  * @bh: The buffer to add
126  * @meta: True in the case of adding metadata
127  *
128  */
129
130 void gfs2_trans_add_bh(struct gfs2_glock *gl, struct buffer_head *bh, int meta)
131 {
132         struct gfs2_sbd *sdp = gl->gl_sbd;
133         struct gfs2_bufdata *bd;
134
135         bd = bh->b_private;
136         if (bd)
137                 gfs2_assert(sdp, bd->bd_gl == gl);
138         else {
139                 gfs2_attach_bufdata(gl, bh, meta);
140                 bd = bh->b_private;
141         }
142         lops_add(sdp, &bd->bd_le);
143 }
144
145 void gfs2_trans_add_revoke(struct gfs2_sbd *sdp, struct gfs2_bufdata *bd)
146 {
147         BUG_ON(!list_empty(&bd->bd_le.le_list));
148         BUG_ON(!list_empty(&bd->bd_ail_st_list));
149         BUG_ON(!list_empty(&bd->bd_ail_gl_list));
150         lops_init_le(&bd->bd_le, &gfs2_revoke_lops);
151         lops_add(sdp, &bd->bd_le);
152 }
153
154 void gfs2_trans_add_unrevoke(struct gfs2_sbd *sdp, u64 blkno)
155 {
156         struct gfs2_bufdata *bd;
157         int found = 0;
158
159         gfs2_log_lock(sdp);
160
161         list_for_each_entry(bd, &sdp->sd_log_le_revoke, bd_le.le_list) {
162                 if (bd->bd_blkno == blkno) {
163                         list_del_init(&bd->bd_le.le_list);
164                         gfs2_assert_withdraw(sdp, sdp->sd_log_num_revoke);
165                         sdp->sd_log_num_revoke--;
166                         found = 1;
167                         break;
168                 }
169         }
170
171         gfs2_log_unlock(sdp);
172
173         if (found) {
174                 struct gfs2_trans *tr = current->journal_info;
175                 kmem_cache_free(gfs2_bufdata_cachep, bd);
176                 tr->tr_num_revoke_rm++;
177         }
178 }
179
180 void gfs2_trans_add_rg(struct gfs2_rgrpd *rgd)
181 {
182         lops_add(rgd->rd_sbd, &rgd->rd_le);
183 }
184