| blob | e1743523f16c2367884d14cd61f0820930385deb |
1 ext4: add BLKDISCARD ioctl
3 The blkdicard ioctl previously only worked on block devices. Allow
4 this ioctl to work on ext4 files.
6 Google-Bug-Id: 11517631
8 Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
9 ---
10 fs/ext4/ext4.h | 5 ++++
11 fs/ext4/extents.c | 38 +++++++++++++++++++++-------
12 fs/ext4/ioctl.c | 139 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
13 3 files changed, 173 insertions(+), 9 deletions(-)
15 diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
16 index 4ce413a..7600dbd 100644
17 --- a/fs/ext4/ext4.h
18 +++ b/fs/ext4/ext4.h
19 @@ -2717,6 +2717,8 @@ extern int ext4_check_blockref(const char *, unsigned int,
20 /* extents.c */
21 struct ext4_ext_path;
22 struct ext4_extent;
23 +typedef int (*extent_iterator_t)(struct inode *inode, struct extent_status *es,
24 + unsigned int flags, void *private);
26 /*
27 * Maximum number of logical blocks in a file; ext4_extent's ee_block is
28 @@ -2762,6 +2764,9 @@ extern int ext4_find_delalloc_range(struct inode *inode,
29 ext4_lblk_t lblk_end);
30 extern int ext4_find_delalloc_cluster(struct inode *inode, ext4_lblk_t lblk);
31 extern ext4_lblk_t ext4_ext_next_allocated_block(struct ext4_ext_path *path);
32 +extern int ext4_extent_iterator(struct inode *inode,
33 + ext4_lblk_t block, ext4_lblk_t num,
34 + extent_iterator_t callback, void *private);
35 extern int ext4_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
36 __u64 start, __u64 len);
37 extern int ext4_ext_precache(struct inode *inode);
38 diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
39 index 556d6b6..dbb8e01 100644
40 --- a/fs/ext4/extents.c
41 +++ b/fs/ext4/extents.c
42 @@ -2148,9 +2148,13 @@ cleanup:
43 return err;
44 }
46 -static int ext4_fill_fiemap_extents(struct inode *inode,
47 - ext4_lblk_t block, ext4_lblk_t num,
48 - struct fiemap_extent_info *fieinfo)
49 +
50 +typedef int (*extent_iterator_t)(struct inode *inode, struct extent_status *es,
51 + unsigned int flags, void *private);
52 +
53 +int ext4_extent_iterator(struct inode *inode,
54 + ext4_lblk_t block, ext4_lblk_t num,
55 + extent_iterator_t callback, void *private)
56 {
57 struct ext4_ext_path *path = NULL;
58 struct ext4_extent *ex;
59 @@ -2159,7 +2163,6 @@ static int ext4_fill_fiemap_extents(struct inode *inode,
60 ext4_lblk_t last = block + num;
61 int exists, depth = 0, err = 0;
62 unsigned int flags = 0;
63 - unsigned char blksize_bits = inode->i_sb->s_blocksize_bits;
65 while (block < last && block != EXT_MAX_BLOCKS) {
66 num = last - block;
67 @@ -2276,11 +2279,7 @@ static int ext4_fill_fiemap_extents(struct inode *inode,
68 }
70 if (exists) {
71 - err = fiemap_fill_next_extent(fieinfo,
72 - (__u64)es.es_lblk << blksize_bits,
73 - (__u64)es.es_pblk << blksize_bits,
74 - (__u64)es.es_len << blksize_bits,
75 - flags);
76 + err = callback(inode, &es, flags, private);
77 if (err < 0)
78 break;
79 if (err == 1) {
80 @@ -2297,6 +2296,27 @@ static int ext4_fill_fiemap_extents(struct inode *inode,
81 return err;
82 }
84 +static int call_fill_fiemap(struct inode *inode, struct extent_status *es,
85 + unsigned int flags, void *private)
86 +{
87 + unsigned char blksize_bits = inode->i_sb->s_blocksize_bits;
88 +
89 + return fiemap_fill_next_extent(private,
90 + (__u64)es->es_lblk << blksize_bits,
91 + (__u64)es->es_pblk << blksize_bits,
92 + (__u64)es->es_len << blksize_bits,
93 + flags);
94 +}
95 +
96 +static int ext4_fill_fiemap_extents(struct inode *inode,
97 + ext4_lblk_t block, ext4_lblk_t num,
98 + struct fiemap_extent_info *fieinfo)
99 +{
100 + return ext4_extent_iterator(inode, block, num,
101 + call_fill_fiemap, fieinfo);
102 +}
103 +
104 +
105 /*
106 * ext4_ext_put_gap_in_cache:
107 * calculate boundaries of the gap that the requested block fits into
108 diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c
109 index 7b377c4..75848bb 100644
110 --- a/fs/ext4/ioctl.c
111 +++ b/fs/ext4/ioctl.c
112 @@ -198,6 +198,132 @@ journal_err_out:
113 return err;
114 }
116 +static int discard_callback(struct inode *inode, struct extent_status *es,
117 + unsigned int flags, void *private)
118 +{
119 + struct ext4_map_blocks *map = private;
120 + ext4_lblk_t es_lblk = es->es_lblk;
121 + ext4_lblk_t es_len = es->es_len;
122 + ext4_fsblk_t es_pblk = es->es_pblk;
123 +
124 + if (flags & (FIEMAP_EXTENT_UNKNOWN |
125 + FIEMAP_EXTENT_ENCODED |
126 + FIEMAP_EXTENT_DATA_ENCRYPTED |
127 + FIEMAP_EXTENT_DELALLOC |
128 + FIEMAP_EXTENT_DATA_TAIL |
129 + FIEMAP_EXTENT_DATA_INLINE |
130 + FIEMAP_EXTENT_NOT_ALIGNED |
131 + FIEMAP_EXTENT_SHARED))
132 + return 0;
133 +
134 + if (es_lblk < map->m_lblk) {
135 + ext4_lblk_t d = map->m_lblk - es_lblk;
136 + if (d > es_len)
137 + return 0;
138 + es_lblk += d;
139 + es_pblk += d;
140 + es_len -= d;
141 + }
142 +
143 + if (es_lblk + es_len > map->m_lblk + map->m_len)
144 + es_len -= es_lblk + es_len - (map->m_lblk + map->m_len);
145 +#ifdef BLKDISCARD_DEBUG
146 + ext4_msg(inode->i_sb, KERN_NOTICE, "discard: %llu len %lu",
147 + (unsigned long long) es_pblk, (unsigned long) es_len);
148 + return 0;
149 +#else
150 + return sb_issue_discard(inode->i_sb, es_pblk, es_len, GFP_KERNEL, 0);
151 +#endif
152 +}
153 +
154 +static int blkdiscard_inode(struct inode *inode, u64 start_offset, u64 len)
155 +{
156 + struct super_block *sb = inode->i_sb;
157 + struct ext4_map_blocks map;
158 + unsigned int num;
159 +
160 + if (!S_ISREG(inode->i_mode))
161 + return -EINVAL;
162 +
163 + if (!blk_queue_discard(bdev_get_queue(sb->s_bdev)))
164 + return -EOPNOTSUPP;
165 +
166 + if (!bdev_discard_zeroes_data(sb->s_bdev) && !capable(CAP_SYS_ADMIN))
167 + return -EOPNOTSUPP;
168 +
169 + num = start_offset & (sb->s_blocksize - 1);
170 + if (num) {
171 + num = sb->s_blocksize - num;
172 + start_offset += num;
173 + len = (len > num) ? len - num : 0;
174 + }
175 + if (len == 0)
176 + return 0;
177 + if (start_offset > sb->s_maxbytes)
178 + return -EFBIG;
179 + if (len > sb->s_maxbytes || (sb->s_maxbytes - len) < start_offset)
180 + len = sb->s_maxbytes - start_offset;
181 +
182 + map.m_lblk = start_offset >> sb->s_blocksize_bits;
183 + map.m_len = len >> sb->s_blocksize_bits;
184 +
185 +#ifdef BLKDISCARD_DEBUG
186 + ext4_msg(sb, KERN_NOTICE, "blkdiscard range: %lu len %lu",
187 + (unsigned long) map.m_lblk, (unsigned long) map.m_len);
188 +#endif
189 +
190 + if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
191 + return ext4_extent_iterator(inode, map.m_lblk, map.m_len,
192 + discard_callback, &map);
193 +
194 + num = map.m_len;
195 + while (num) {
196 + int ret = ext4_map_blocks(NULL, inode, &map, 0);
197 +
198 + if (ret < 0)
199 + return ret;
200 +
201 + if (ret == 0) {
202 +#ifdef BLKDISCARD_DEBUG
203 + ext4_msg(sb, KERN_NOTICE,
204 + "skip: lblk %lu len %lu ret %lu num %lu",
205 + (unsigned long) map.m_lblk,
206 + (unsigned long) map.m_len,
207 + (unsigned long) ret,
208 + (unsigned long) num);
209 +#endif
210 + map.m_lblk++;
211 + num--;
212 + continue;
213 + }
214 +#ifdef BLKDISCARD_DEBUG
215 + ext4_msg(sb, KERN_NOTICE,
216 + "walk: lblk %lu pblk %llu len %lu ret %lu num %lu",
217 + (unsigned long) map.m_lblk,
218 + (unsigned long long) map.m_pblk,
219 + (unsigned long) map.m_len,
220 + (unsigned long) ret,
221 + (unsigned long) num);
222 +#endif
223 + if (ret > num)
224 + ret = num;
225 + map.m_lblk += ret;
226 + num -= ret;
227 + map.m_len = num;
228 +
229 +#ifdef BLKDISCARD_DEBUG
230 + ext4_msg(sb, KERN_NOTICE, "discard: %llu len %lu",
231 + (unsigned long long) map.m_pblk, (unsigned long) ret);
232 +#else
233 + ret = sb_issue_discard(sb, map.m_pblk, ret,
234 + GFP_KERNEL, 0);
235 + if (ret)
236 + return ret;
237 +#endif
238 + }
239 + return 0;
240 +}
241 +
242 long ext4_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
243 {
244 struct inode *inode = file_inode(filp);
245 @@ -618,6 +744,18 @@ resizefs_out:
246 case EXT4_IOC_PRECACHE_EXTENTS:
247 return ext4_ext_precache(inode);
249 + case BLKDISCARD: {
250 + uint64_t range[2];
251 +
252 + if (!(filp->f_mode & FMODE_WRITE))
253 + return -EBADF;
254 +
255 + if (copy_from_user(range, (void __user *)arg, sizeof(range)))
256 + return -EFAULT;
257 +
258 + return blkdiscard_inode(file_inode(filp), range[0], range[1]);
259 + }
260 +
261 default:
262 return -ENOTTY;
263 }
264 @@ -682,6 +820,7 @@ long ext4_compat_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
265 case FITRIM:
266 case EXT4_IOC_RESIZE_FS:
267 case EXT4_IOC_PRECACHE_EXTENTS:
268 + case BLKDISCARD:
269 break;
270 default:
271 return -ENOIOCTLCMD;