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| 165 | fiemap (eio_req *req) |
165 | fiemap (eio_req *req) |
| 166 | { |
166 | { |
| 167 | req->result = -1; |
167 | req->result = -1; |
| 168 | |
168 | |
| 169 | #if HAVE_FIEMAP |
169 | #if HAVE_FIEMAP |
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170 | /* assume some c99 */ |
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171 | struct fiemap *fiemap = 0; |
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172 | size_t end_offset; |
| 170 | int count = req->int3; |
173 | int count = req->int3; |
| 171 | |
174 | |
| 172 | /* heuristic: first try with 72 extents if we don't know how many, */ |
175 | req->flags |= EIO_FLAG_PTR1_FREE; |
| 173 | /* as most files have (hopefully) fewer than this many extents */ |
176 | |
| 174 | /* in fact, most should have <= 2, so the 72 below is probably overkill */ |
177 | /* heuristic: start with 512 bytes (8 extents), and if that isn't enough, */ |
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178 | /* increase in 3.5kb steps */ |
| 175 | if (count < 0) |
179 | if (count < 0) |
| 176 | count = 72; /* for what it's worth, 72 extents fit nicely into 4kb */ |
180 | count = 8; |
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181 | |
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182 | fiemap = malloc (sizeof (*fiemap) + sizeof (struct fiemap_extent) * count); |
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183 | errno = ENOMEM; |
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184 | if (!fiemap) |
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185 | return; |
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186 | |
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187 | req->ptr1 = fiemap; |
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188 | |
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189 | fiemap->fm_start = req->offs; |
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190 | fiemap->fm_length = req->size; |
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191 | fiemap->fm_flags = req->int2; |
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192 | fiemap->fm_extent_count = count; |
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193 | |
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194 | if (ioctl (req->int1, FS_IOC_FIEMAP, fiemap)) |
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195 | return; |
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196 | |
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197 | if (req->int3 >= 0 /* not autosizing */ |
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198 | || !fiemap->fm_mapped_extents /* no more extents */ |
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199 | || fiemap->fm_extents [fiemap->fm_mapped_extents - 1].fe_flags & FIEMAP_EXTENT_LAST /* hit eof */) |
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200 | goto done; |
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201 | |
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202 | /* else we have to loop - |
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203 | * it would be tempting (atcually I tried that first) to just query the |
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204 | * number of extents needed, but linux often feels like not returning all |
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205 | * extents, without telling us it left any out. this complicates |
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206 | * this quite a bit. |
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207 | */ |
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208 | |
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209 | end_offset = fiemap->fm_length + (fiemap->fm_length == FIEMAP_MAX_OFFSET ? 0 : fiemap->fm_start); |
| 177 | |
210 | |
| 178 | for (;;) |
211 | for (;;) |
| 179 | { |
212 | { |
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213 | /* we go in 54 extent steps - 3kb, in the hope that this fits nicely on the eio stack (normally 16+ kb) */ |
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214 | char scratch[3072]; |
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215 | struct fiemap *incmap = (struct fiemap *)scratch; |
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216 | |
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217 | incmap->fm_start = fiemap->fm_extents [fiemap->fm_mapped_extents - 1].fe_logical |
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218 | + fiemap->fm_extents [fiemap->fm_mapped_extents - 1].fe_length; |
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219 | incmap->fm_length = fiemap->fm_length - (incmap->fm_start - fiemap->fm_start); |
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220 | incmap->fm_flags = fiemap->fm_flags; |
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221 | incmap->fm_extent_count = (sizeof (scratch) - sizeof (struct fiemap)) / sizeof (struct fiemap_extent); |
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222 | |
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223 | if (ioctl (req->int1, FS_IOC_FIEMAP, incmap)) |
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224 | return; |
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225 | |
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226 | count = fiemap->fm_mapped_extents + incmap->fm_mapped_extents; |
| 180 | struct fiemap *fiemap = malloc (sizeof (*fiemap) + sizeof (struct fiemap_extent) * count); |
227 | fiemap = realloc (fiemap, sizeof (*fiemap) + sizeof (struct fiemap_extent) * count); |
| 181 | errno = ENOMEM; |
228 | errno = ENOMEM; |
| 182 | if (!fiemap) |
229 | if (!fiemap) |
| 183 | return; |
230 | return; |
| 184 | |
231 | |
| 185 | req->ptr1 = fiemap; |
232 | req->ptr1 = fiemap; |
| 186 | req->flags |= EIO_FLAG_PTR1_FREE; |
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| 187 | |
233 | |
| 188 | fiemap->fm_start = req->offs; |
234 | for (count = 0; count < incmap->fm_mapped_extents; ++count) |
| 189 | fiemap->fm_length = req->size; |
235 | { |
| 190 | fiemap->fm_flags = req->int2; |
236 | struct fiemap_extent *e = incmap->fm_extents + count; |
| 191 | fiemap->fm_extent_count = count; |
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| 192 | |
237 | |
| 193 | if (ioctl (req->int1, FS_IOC_FIEMAP, fiemap)) |
238 | if (e->fe_logical + e->fe_length >= end_offset) |
| 194 | return; |
239 | goto done; |
| 195 | |
240 | |
| 196 | if (req->int3 >= 0) |
241 | fiemap->fm_extents [fiemap->fm_mapped_extents++] = *e; |
| 197 | break; /* when not autosizing we are done */ |
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| 198 | |
242 | |
| 199 | if (fiemap->fm_mapped_extents < count) |
243 | if (e->fe_flags & FIEMAP_EXTENT_LAST) |
| 200 | /* either autosizing succeeded, |
244 | goto done; |
| 201 | * or the file had no extents |
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| 202 | * or we luckily had enough space */ |
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| 203 | break; |
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| 204 | |
245 | |
| 205 | /* some kernels overwrite fm_length, so just reset everything */ |
246 | } |
| 206 | fiemap->fm_start = req->offs; |
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| 207 | fiemap->fm_length = req->size; |
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| 208 | fiemap->fm_flags = req->int2; |
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| 209 | fiemap->fm_extent_count = 0; |
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| 210 | |
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| 211 | if (ioctl (req->int1, FS_IOC_FIEMAP, fiemap)) |
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| 212 | return; |
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| 213 | |
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| 214 | /* to work around a kernel bug, we allocate one more */ |
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| 215 | count = fiemap->fm_mapped_extents + 1; |
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| 216 | |
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| 217 | free (fiemap); |
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| 218 | } |
247 | } |
| 219 | |
248 | |
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249 | done: |
| 220 | req->result = 0; |
250 | req->result = 0; |
| 221 | |
251 | |
| 222 | #else |
252 | #else |
| 223 | errno = ENOSYS; |
253 | errno = ENOSYS; |
| 224 | #endif |
254 | #endif |
