1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Interface between ext4 and JBD
4  */
5 
6 #include "ext4_jbd2.h"
7 
8 #include <trace/events/ext4.h>
9 
10 /* Just increment the non-pointer handle value */
ext4_get_nojournal(void)11 static handle_t *ext4_get_nojournal(void)
12 {
13 	handle_t *handle = current->journal_info;
14 	unsigned long ref_cnt = (unsigned long)handle;
15 
16 	BUG_ON(ref_cnt >= EXT4_NOJOURNAL_MAX_REF_COUNT);
17 
18 	ref_cnt++;
19 	handle = (handle_t *)ref_cnt;
20 
21 	current->journal_info = handle;
22 	return handle;
23 }
24 
25 
26 /* Decrement the non-pointer handle value */
ext4_put_nojournal(handle_t * handle)27 static void ext4_put_nojournal(handle_t *handle)
28 {
29 	unsigned long ref_cnt = (unsigned long)handle;
30 
31 	BUG_ON(ref_cnt == 0);
32 
33 	ref_cnt--;
34 	handle = (handle_t *)ref_cnt;
35 
36 	current->journal_info = handle;
37 }
38 
39 /*
40  * Wrappers for jbd2_journal_start/end.
41  */
ext4_journal_check_start(struct super_block * sb)42 static int ext4_journal_check_start(struct super_block *sb)
43 {
44 	journal_t *journal;
45 
46 	might_sleep();
47 
48 	if (unlikely(ext4_forced_shutdown(EXT4_SB(sb))))
49 		return -EIO;
50 
51 	if (sb_rdonly(sb))
52 		return -EROFS;
53 	WARN_ON(sb->s_writers.frozen == SB_FREEZE_COMPLETE);
54 	journal = EXT4_SB(sb)->s_journal;
55 	/*
56 	 * Special case here: if the journal has aborted behind our
57 	 * backs (eg. EIO in the commit thread), then we still need to
58 	 * take the FS itself readonly cleanly.
59 	 */
60 	if (journal && is_journal_aborted(journal)) {
61 		ext4_abort(sb, "Detected aborted journal");
62 		return -EROFS;
63 	}
64 	return 0;
65 }
66 
__ext4_journal_start_sb(struct super_block * sb,unsigned int line,int type,int blocks,int rsv_blocks)67 handle_t *__ext4_journal_start_sb(struct super_block *sb, unsigned int line,
68 				  int type, int blocks, int rsv_blocks)
69 {
70 	journal_t *journal;
71 	int err;
72 
73 	trace_ext4_journal_start(sb, blocks, rsv_blocks, _RET_IP_);
74 	err = ext4_journal_check_start(sb);
75 	if (err < 0)
76 		return ERR_PTR(err);
77 
78 	journal = EXT4_SB(sb)->s_journal;
79 	if (!journal)
80 		return ext4_get_nojournal();
81 	return jbd2__journal_start(journal, blocks, rsv_blocks, GFP_NOFS,
82 				   type, line);
83 }
84 
__ext4_journal_stop(const char * where,unsigned int line,handle_t * handle)85 int __ext4_journal_stop(const char *where, unsigned int line, handle_t *handle)
86 {
87 	struct super_block *sb;
88 	int err;
89 	int rc;
90 
91 	if (!ext4_handle_valid(handle)) {
92 		ext4_put_nojournal(handle);
93 		return 0;
94 	}
95 
96 	err = handle->h_err;
97 	if (!handle->h_transaction) {
98 		rc = jbd2_journal_stop(handle);
99 		return err ? err : rc;
100 	}
101 
102 	sb = handle->h_transaction->t_journal->j_private;
103 	rc = jbd2_journal_stop(handle);
104 
105 	if (!err)
106 		err = rc;
107 	if (err)
108 		__ext4_std_error(sb, where, line, err);
109 	return err;
110 }
111 
__ext4_journal_start_reserved(handle_t * handle,unsigned int line,int type)112 handle_t *__ext4_journal_start_reserved(handle_t *handle, unsigned int line,
113 					int type)
114 {
115 	struct super_block *sb;
116 	int err;
117 
118 	if (!ext4_handle_valid(handle))
119 		return ext4_get_nojournal();
120 
121 	sb = handle->h_journal->j_private;
122 	trace_ext4_journal_start_reserved(sb, handle->h_buffer_credits,
123 					  _RET_IP_);
124 	err = ext4_journal_check_start(sb);
125 	if (err < 0) {
126 		jbd2_journal_free_reserved(handle);
127 		return ERR_PTR(err);
128 	}
129 
130 	err = jbd2_journal_start_reserved(handle, type, line);
131 	if (err < 0)
132 		return ERR_PTR(err);
133 	return handle;
134 }
135 
ext4_journal_abort_handle(const char * caller,unsigned int line,const char * err_fn,struct buffer_head * bh,handle_t * handle,int err)136 static void ext4_journal_abort_handle(const char *caller, unsigned int line,
137 				      const char *err_fn,
138 				      struct buffer_head *bh,
139 				      handle_t *handle, int err)
140 {
141 	char nbuf[16];
142 	const char *errstr = ext4_decode_error(NULL, err, nbuf);
143 
144 	BUG_ON(!ext4_handle_valid(handle));
145 
146 	if (bh)
147 		BUFFER_TRACE(bh, "abort");
148 
149 	if (!handle->h_err)
150 		handle->h_err = err;
151 
152 	if (is_handle_aborted(handle))
153 		return;
154 
155 	printk(KERN_ERR "EXT4-fs: %s:%d: aborting transaction: %s in %s\n",
156 	       caller, line, errstr, err_fn);
157 
158 	jbd2_journal_abort_handle(handle);
159 }
160 
__ext4_journal_get_write_access(const char * where,unsigned int line,handle_t * handle,struct buffer_head * bh)161 int __ext4_journal_get_write_access(const char *where, unsigned int line,
162 				    handle_t *handle, struct buffer_head *bh)
163 {
164 	int err = 0;
165 
166 	might_sleep();
167 
168 	if (ext4_handle_valid(handle)) {
169 		err = jbd2_journal_get_write_access(handle, bh);
170 		if (err)
171 			ext4_journal_abort_handle(where, line, __func__, bh,
172 						  handle, err);
173 	}
174 	return err;
175 }
176 
177 /*
178  * The ext4 forget function must perform a revoke if we are freeing data
179  * which has been journaled.  Metadata (eg. indirect blocks) must be
180  * revoked in all cases.
181  *
182  * "bh" may be NULL: a metadata block may have been freed from memory
183  * but there may still be a record of it in the journal, and that record
184  * still needs to be revoked.
185  *
186  * If the handle isn't valid we're not journaling, but we still need to
187  * call into ext4_journal_revoke() to put the buffer head.
188  */
__ext4_forget(const char * where,unsigned int line,handle_t * handle,int is_metadata,struct inode * inode,struct buffer_head * bh,ext4_fsblk_t blocknr)189 int __ext4_forget(const char *where, unsigned int line, handle_t *handle,
190 		  int is_metadata, struct inode *inode,
191 		  struct buffer_head *bh, ext4_fsblk_t blocknr)
192 {
193 	int err;
194 
195 	might_sleep();
196 
197 	trace_ext4_forget(inode, is_metadata, blocknr);
198 	BUFFER_TRACE(bh, "enter");
199 
200 	jbd_debug(4, "forgetting bh %p: is_metadata = %d, mode %o, "
201 		  "data mode %x\n",
202 		  bh, is_metadata, inode->i_mode,
203 		  test_opt(inode->i_sb, DATA_FLAGS));
204 
205 	/* In the no journal case, we can just do a bforget and return */
206 	if (!ext4_handle_valid(handle)) {
207 		bforget(bh);
208 		return 0;
209 	}
210 
211 	/* Never use the revoke function if we are doing full data
212 	 * journaling: there is no need to, and a V1 superblock won't
213 	 * support it.  Otherwise, only skip the revoke on un-journaled
214 	 * data blocks. */
215 
216 	if (test_opt(inode->i_sb, DATA_FLAGS) == EXT4_MOUNT_JOURNAL_DATA ||
217 	    (!is_metadata && !ext4_should_journal_data(inode))) {
218 		if (bh) {
219 			BUFFER_TRACE(bh, "call jbd2_journal_forget");
220 			err = jbd2_journal_forget(handle, bh);
221 			if (err)
222 				ext4_journal_abort_handle(where, line, __func__,
223 							  bh, handle, err);
224 			return err;
225 		}
226 		return 0;
227 	}
228 
229 	/*
230 	 * data!=journal && (is_metadata || should_journal_data(inode))
231 	 */
232 	BUFFER_TRACE(bh, "call jbd2_journal_revoke");
233 	err = jbd2_journal_revoke(handle, blocknr, bh);
234 	if (err) {
235 		ext4_journal_abort_handle(where, line, __func__,
236 					  bh, handle, err);
237 		__ext4_abort(inode->i_sb, where, line,
238 			   "error %d when attempting revoke", err);
239 	}
240 	BUFFER_TRACE(bh, "exit");
241 	return err;
242 }
243 
__ext4_journal_get_create_access(const char * where,unsigned int line,handle_t * handle,struct buffer_head * bh)244 int __ext4_journal_get_create_access(const char *where, unsigned int line,
245 				handle_t *handle, struct buffer_head *bh)
246 {
247 	int err = 0;
248 
249 	if (ext4_handle_valid(handle)) {
250 		err = jbd2_journal_get_create_access(handle, bh);
251 		if (err)
252 			ext4_journal_abort_handle(where, line, __func__,
253 						  bh, handle, err);
254 	}
255 	return err;
256 }
257 
__ext4_handle_dirty_metadata(const char * where,unsigned int line,handle_t * handle,struct inode * inode,struct buffer_head * bh)258 int __ext4_handle_dirty_metadata(const char *where, unsigned int line,
259 				 handle_t *handle, struct inode *inode,
260 				 struct buffer_head *bh)
261 {
262 	int err = 0;
263 
264 	might_sleep();
265 
266 	set_buffer_meta(bh);
267 	set_buffer_prio(bh);
268 	if (ext4_handle_valid(handle)) {
269 		err = jbd2_journal_dirty_metadata(handle, bh);
270 		/* Errors can only happen due to aborted journal or a nasty bug */
271 		if (!is_handle_aborted(handle) && WARN_ON_ONCE(err)) {
272 			ext4_journal_abort_handle(where, line, __func__, bh,
273 						  handle, err);
274 			if (inode == NULL) {
275 				pr_err("EXT4: jbd2_journal_dirty_metadata "
276 				       "failed: handle type %u started at "
277 				       "line %u, credits %u/%u, errcode %d",
278 				       handle->h_type,
279 				       handle->h_line_no,
280 				       handle->h_requested_credits,
281 				       handle->h_buffer_credits, err);
282 				return err;
283 			}
284 			ext4_error_inode(inode, where, line,
285 					 bh->b_blocknr,
286 					 "journal_dirty_metadata failed: "
287 					 "handle type %u started at line %u, "
288 					 "credits %u/%u, errcode %d",
289 					 handle->h_type,
290 					 handle->h_line_no,
291 					 handle->h_requested_credits,
292 					 handle->h_buffer_credits, err);
293 		}
294 	} else {
295 		if (inode)
296 			mark_buffer_dirty_inode(bh, inode);
297 		else
298 			mark_buffer_dirty(bh);
299 		if (inode && inode_needs_sync(inode)) {
300 			sync_dirty_buffer(bh);
301 			if (buffer_req(bh) && !buffer_uptodate(bh)) {
302 				struct ext4_super_block *es;
303 
304 				es = EXT4_SB(inode->i_sb)->s_es;
305 				es->s_last_error_block =
306 					cpu_to_le64(bh->b_blocknr);
307 				ext4_error_inode(inode, where, line,
308 						 bh->b_blocknr,
309 					"IO error syncing itable block");
310 				err = -EIO;
311 			}
312 		}
313 	}
314 	return err;
315 }
316 
__ext4_handle_dirty_super(const char * where,unsigned int line,handle_t * handle,struct super_block * sb)317 int __ext4_handle_dirty_super(const char *where, unsigned int line,
318 			      handle_t *handle, struct super_block *sb)
319 {
320 	struct buffer_head *bh = EXT4_SB(sb)->s_sbh;
321 	int err = 0;
322 
323 	ext4_superblock_csum_set(sb);
324 	if (ext4_handle_valid(handle)) {
325 		err = jbd2_journal_dirty_metadata(handle, bh);
326 		if (err)
327 			ext4_journal_abort_handle(where, line, __func__,
328 						  bh, handle, err);
329 	} else
330 		mark_buffer_dirty(bh);
331 	return err;
332 }
333