1 /*
2  * Copyright 2000 by Hans Reiser, licensing governed by reiserfs/README
3  */
4 
5 #include <linux/time.h>
6 #include "reiserfs.h"
7 #include "acl.h"
8 #include "xattr.h"
9 #include <linux/uaccess.h>
10 #include <linux/pagemap.h>
11 #include <linux/swap.h>
12 #include <linux/writeback.h>
13 #include <linux/blkdev.h>
14 #include <linux/buffer_head.h>
15 #include <linux/quotaops.h>
16 
17 /*
18  * We pack the tails of files on file close, not at the time they are written.
19  * This implies an unnecessary copy of the tail and an unnecessary indirect item
20  * insertion/balancing, for files that are written in one write.
21  * It avoids unnecessary tail packings (balances) for files that are written in
22  * multiple writes and are small enough to have tails.
23  *
24  * file_release is called by the VFS layer when the file is closed.  If
25  * this is the last open file descriptor, and the file
26  * small enough to have a tail, and the tail is currently in an
27  * unformatted node, the tail is converted back into a direct item.
28  *
29  * We use reiserfs_truncate_file to pack the tail, since it already has
30  * all the conditions coded.
31  */
reiserfs_file_release(struct inode * inode,struct file * filp)32 static int reiserfs_file_release(struct inode *inode, struct file *filp)
33 {
34 
35 	struct reiserfs_transaction_handle th;
36 	int err;
37 	int jbegin_failure = 0;
38 
39 	BUG_ON(!S_ISREG(inode->i_mode));
40 
41 	if (!atomic_dec_and_mutex_lock(&REISERFS_I(inode)->openers,
42 				       &REISERFS_I(inode)->tailpack))
43 		return 0;
44 
45 	/* fast out for when nothing needs to be done */
46 	if ((!(REISERFS_I(inode)->i_flags & i_pack_on_close_mask) ||
47 	     !tail_has_to_be_packed(inode)) &&
48 	    REISERFS_I(inode)->i_prealloc_count <= 0) {
49 		mutex_unlock(&REISERFS_I(inode)->tailpack);
50 		return 0;
51 	}
52 
53 	reiserfs_write_lock(inode->i_sb);
54 	/*
55 	 * freeing preallocation only involves relogging blocks that
56 	 * are already in the current transaction.  preallocation gets
57 	 * freed at the end of each transaction, so it is impossible for
58 	 * us to log any additional blocks (including quota blocks)
59 	 */
60 	err = journal_begin(&th, inode->i_sb, 1);
61 	if (err) {
62 		/*
63 		 * uh oh, we can't allow the inode to go away while there
64 		 * is still preallocation blocks pending.  Try to join the
65 		 * aborted transaction
66 		 */
67 		jbegin_failure = err;
68 		err = journal_join_abort(&th, inode->i_sb);
69 
70 		if (err) {
71 			/*
72 			 * hmpf, our choices here aren't good.  We can pin
73 			 * the inode which will disallow unmount from ever
74 			 * happening, we can do nothing, which will corrupt
75 			 * random memory on unmount, or we can forcibly
76 			 * remove the file from the preallocation list, which
77 			 * will leak blocks on disk.  Lets pin the inode
78 			 * and let the admin know what is going on.
79 			 */
80 			igrab(inode);
81 			reiserfs_warning(inode->i_sb, "clm-9001",
82 					 "pinning inode %lu because the "
83 					 "preallocation can't be freed",
84 					 inode->i_ino);
85 			goto out;
86 		}
87 	}
88 	reiserfs_update_inode_transaction(inode);
89 
90 #ifdef REISERFS_PREALLOCATE
91 	reiserfs_discard_prealloc(&th, inode);
92 #endif
93 	err = journal_end(&th);
94 
95 	/* copy back the error code from journal_begin */
96 	if (!err)
97 		err = jbegin_failure;
98 
99 	if (!err &&
100 	    (REISERFS_I(inode)->i_flags & i_pack_on_close_mask) &&
101 	    tail_has_to_be_packed(inode)) {
102 
103 		/*
104 		 * if regular file is released by last holder and it has been
105 		 * appended (we append by unformatted node only) or its direct
106 		 * item(s) had to be converted, then it may have to be
107 		 * indirect2direct converted
108 		 */
109 		err = reiserfs_truncate_file(inode, 0);
110 	}
111 out:
112 	reiserfs_write_unlock(inode->i_sb);
113 	mutex_unlock(&REISERFS_I(inode)->tailpack);
114 	return err;
115 }
116 
reiserfs_file_open(struct inode * inode,struct file * file)117 static int reiserfs_file_open(struct inode *inode, struct file *file)
118 {
119 	int err = dquot_file_open(inode, file);
120 
121 	/* somebody might be tailpacking on final close; wait for it */
122         if (!atomic_inc_not_zero(&REISERFS_I(inode)->openers)) {
123 		mutex_lock(&REISERFS_I(inode)->tailpack);
124 		atomic_inc(&REISERFS_I(inode)->openers);
125 		mutex_unlock(&REISERFS_I(inode)->tailpack);
126 	}
127 	return err;
128 }
129 
reiserfs_vfs_truncate_file(struct inode * inode)130 void reiserfs_vfs_truncate_file(struct inode *inode)
131 {
132 	mutex_lock(&REISERFS_I(inode)->tailpack);
133 	reiserfs_truncate_file(inode, 1);
134 	mutex_unlock(&REISERFS_I(inode)->tailpack);
135 }
136 
137 /* Sync a reiserfs file. */
138 
139 /*
140  * FIXME: sync_mapping_buffers() never has anything to sync.  Can
141  * be removed...
142  */
143 
reiserfs_sync_file(struct file * filp,loff_t start,loff_t end,int datasync)144 static int reiserfs_sync_file(struct file *filp, loff_t start, loff_t end,
145 			      int datasync)
146 {
147 	struct inode *inode = filp->f_mapping->host;
148 	int err;
149 	int barrier_done;
150 
151 	err = file_write_and_wait_range(filp, start, end);
152 	if (err)
153 		return err;
154 
155 	inode_lock(inode);
156 	BUG_ON(!S_ISREG(inode->i_mode));
157 	err = sync_mapping_buffers(inode->i_mapping);
158 	reiserfs_write_lock(inode->i_sb);
159 	barrier_done = reiserfs_commit_for_inode(inode);
160 	reiserfs_write_unlock(inode->i_sb);
161 	if (barrier_done != 1 && reiserfs_barrier_flush(inode->i_sb))
162 		blkdev_issue_flush(inode->i_sb->s_bdev);
163 	inode_unlock(inode);
164 	if (barrier_done < 0)
165 		return barrier_done;
166 	return (err < 0) ? -EIO : 0;
167 }
168 
169 /* taken fs/buffer.c:__block_commit_write */
reiserfs_commit_page(struct inode * inode,struct page * page,unsigned from,unsigned to)170 int reiserfs_commit_page(struct inode *inode, struct page *page,
171 			 unsigned from, unsigned to)
172 {
173 	unsigned block_start, block_end;
174 	int partial = 0;
175 	unsigned blocksize;
176 	struct buffer_head *bh, *head;
177 	unsigned long i_size_index = inode->i_size >> PAGE_SHIFT;
178 	int new;
179 	int logit = reiserfs_file_data_log(inode);
180 	struct super_block *s = inode->i_sb;
181 	int bh_per_page = PAGE_SIZE / s->s_blocksize;
182 	struct reiserfs_transaction_handle th;
183 	int ret = 0;
184 
185 	th.t_trans_id = 0;
186 	blocksize = i_blocksize(inode);
187 
188 	if (logit) {
189 		reiserfs_write_lock(s);
190 		ret = journal_begin(&th, s, bh_per_page + 1);
191 		if (ret)
192 			goto drop_write_lock;
193 		reiserfs_update_inode_transaction(inode);
194 	}
195 	for (bh = head = page_buffers(page), block_start = 0;
196 	     bh != head || !block_start;
197 	     block_start = block_end, bh = bh->b_this_page) {
198 
199 		new = buffer_new(bh);
200 		clear_buffer_new(bh);
201 		block_end = block_start + blocksize;
202 		if (block_end <= from || block_start >= to) {
203 			if (!buffer_uptodate(bh))
204 				partial = 1;
205 		} else {
206 			set_buffer_uptodate(bh);
207 			if (logit) {
208 				reiserfs_prepare_for_journal(s, bh, 1);
209 				journal_mark_dirty(&th, bh);
210 			} else if (!buffer_dirty(bh)) {
211 				mark_buffer_dirty(bh);
212 				/*
213 				 * do data=ordered on any page past the end
214 				 * of file and any buffer marked BH_New.
215 				 */
216 				if (reiserfs_data_ordered(inode->i_sb) &&
217 				    (new || page->index >= i_size_index)) {
218 					reiserfs_add_ordered_list(inode, bh);
219 				}
220 			}
221 		}
222 	}
223 	if (logit) {
224 		ret = journal_end(&th);
225 drop_write_lock:
226 		reiserfs_write_unlock(s);
227 	}
228 	/*
229 	 * If this is a partial write which happened to make all buffers
230 	 * uptodate then we can optimize away a bogus read_folio() for
231 	 * the next read(). Here we 'discover' whether the page went
232 	 * uptodate as a result of this (potentially partial) write.
233 	 */
234 	if (!partial)
235 		SetPageUptodate(page);
236 	return ret;
237 }
238 
239 const struct file_operations reiserfs_file_operations = {
240 	.unlocked_ioctl = reiserfs_ioctl,
241 #ifdef CONFIG_COMPAT
242 	.compat_ioctl = reiserfs_compat_ioctl,
243 #endif
244 	.mmap = generic_file_mmap,
245 	.open = reiserfs_file_open,
246 	.release = reiserfs_file_release,
247 	.fsync = reiserfs_sync_file,
248 	.read_iter = generic_file_read_iter,
249 	.write_iter = generic_file_write_iter,
250 	.splice_read = generic_file_splice_read,
251 	.splice_write = iter_file_splice_write,
252 	.llseek = generic_file_llseek,
253 };
254 
255 const struct inode_operations reiserfs_file_inode_operations = {
256 	.setattr = reiserfs_setattr,
257 	.listxattr = reiserfs_listxattr,
258 	.permission = reiserfs_permission,
259 	.get_acl = reiserfs_get_acl,
260 	.set_acl = reiserfs_set_acl,
261 	.fileattr_get = reiserfs_fileattr_get,
262 	.fileattr_set = reiserfs_fileattr_set,
263 };
264