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authorZach Brown <zach.brown@oracle.com>2005-12-15 17:28:17 -0500
committerJoel Becker <joel.becker@oracle.com>2006-01-03 14:45:42 -0500
commit994fc28c7b1e697ac56befe4aecabf23f0689f46 (patch)
treeda36d162e9bd077e9b5be385b28e2db90475c263 /drivers
parent7063fbf2261194f72ee75afca67b3b38b554b5fa (diff)
[PATCH] add AOP_TRUNCATED_PAGE, prepend AOP_ to WRITEPAGE_ACTIVATE
readpage(), prepare_write(), and commit_write() callers are updated to understand the special return code AOP_TRUNCATED_PAGE in the style of writepage() and WRITEPAGE_ACTIVATE. AOP_TRUNCATED_PAGE tells the caller that the callee has unlocked the page and that the operation should be tried again with a new page. OCFS2 uses this to detect and work around a lock inversion in its aop methods. There should be no change in behaviour for methods that don't return AOP_TRUNCATED_PAGE. WRITEPAGE_ACTIVATE is also prepended with AOP_ for consistency and they are made enums so that kerneldoc can be used to document their semantics. Signed-off-by: Zach Brown <zach.brown@oracle.com>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/block/loop.c23
-rw-r--r--drivers/block/rd.c4
2 files changed, 20 insertions, 7 deletions
diff --git a/drivers/block/loop.c b/drivers/block/loop.c
index 96c664af8d06..a452b13620a2 100644
--- a/drivers/block/loop.c
+++ b/drivers/block/loop.c
@@ -213,7 +213,7 @@ static int do_lo_send_aops(struct loop_device *lo, struct bio_vec *bvec,
213 struct address_space_operations *aops = mapping->a_ops; 213 struct address_space_operations *aops = mapping->a_ops;
214 pgoff_t index; 214 pgoff_t index;
215 unsigned offset, bv_offs; 215 unsigned offset, bv_offs;
216 int len, ret = 0; 216 int len, ret;
217 217
218 down(&mapping->host->i_sem); 218 down(&mapping->host->i_sem);
219 index = pos >> PAGE_CACHE_SHIFT; 219 index = pos >> PAGE_CACHE_SHIFT;
@@ -232,9 +232,15 @@ static int do_lo_send_aops(struct loop_device *lo, struct bio_vec *bvec,
232 page = grab_cache_page(mapping, index); 232 page = grab_cache_page(mapping, index);
233 if (unlikely(!page)) 233 if (unlikely(!page))
234 goto fail; 234 goto fail;
235 if (unlikely(aops->prepare_write(file, page, offset, 235 ret = aops->prepare_write(file, page, offset,
236 offset + size))) 236 offset + size);
237 if (unlikely(ret)) {
238 if (ret == AOP_TRUNCATED_PAGE) {
239 page_cache_release(page);
240 continue;
241 }
237 goto unlock; 242 goto unlock;
243 }
238 transfer_result = lo_do_transfer(lo, WRITE, page, offset, 244 transfer_result = lo_do_transfer(lo, WRITE, page, offset,
239 bvec->bv_page, bv_offs, size, IV); 245 bvec->bv_page, bv_offs, size, IV);
240 if (unlikely(transfer_result)) { 246 if (unlikely(transfer_result)) {
@@ -251,9 +257,15 @@ static int do_lo_send_aops(struct loop_device *lo, struct bio_vec *bvec,
251 kunmap_atomic(kaddr, KM_USER0); 257 kunmap_atomic(kaddr, KM_USER0);
252 } 258 }
253 flush_dcache_page(page); 259 flush_dcache_page(page);
254 if (unlikely(aops->commit_write(file, page, offset, 260 ret = aops->commit_write(file, page, offset,
255 offset + size))) 261 offset + size);
262 if (unlikely(ret)) {
263 if (ret == AOP_TRUNCATED_PAGE) {
264 page_cache_release(page);
265 continue;
266 }
256 goto unlock; 267 goto unlock;
268 }
257 if (unlikely(transfer_result)) 269 if (unlikely(transfer_result))
258 goto unlock; 270 goto unlock;
259 bv_offs += size; 271 bv_offs += size;
@@ -264,6 +276,7 @@ static int do_lo_send_aops(struct loop_device *lo, struct bio_vec *bvec,
264 unlock_page(page); 276 unlock_page(page);
265 page_cache_release(page); 277 page_cache_release(page);
266 } 278 }
279 ret = 0;
267out: 280out:
268 up(&mapping->host->i_sem); 281 up(&mapping->host->i_sem);
269 return ret; 282 return ret;
diff --git a/drivers/block/rd.c b/drivers/block/rd.c
index 68c60a5bcdab..ffd6abd6d5a0 100644
--- a/drivers/block/rd.c
+++ b/drivers/block/rd.c
@@ -154,7 +154,7 @@ static int ramdisk_commit_write(struct file *file, struct page *page,
154 154
155/* 155/*
156 * ->writepage to the the blockdev's mapping has to redirty the page so that the 156 * ->writepage to the the blockdev's mapping has to redirty the page so that the
157 * VM doesn't go and steal it. We return WRITEPAGE_ACTIVATE so that the VM 157 * VM doesn't go and steal it. We return AOP_WRITEPAGE_ACTIVATE so that the VM
158 * won't try to (pointlessly) write the page again for a while. 158 * won't try to (pointlessly) write the page again for a while.
159 * 159 *
160 * Really, these pages should not be on the LRU at all. 160 * Really, these pages should not be on the LRU at all.
@@ -165,7 +165,7 @@ static int ramdisk_writepage(struct page *page, struct writeback_control *wbc)
165 make_page_uptodate(page); 165 make_page_uptodate(page);
166 SetPageDirty(page); 166 SetPageDirty(page);
167 if (wbc->for_reclaim) 167 if (wbc->for_reclaim)
168 return WRITEPAGE_ACTIVATE; 168 return AOP_WRITEPAGE_ACTIVATE;
169 unlock_page(page); 169 unlock_page(page);
170 return 0; 170 return 0;
171} 171}