a7y18lte-ubports/android_kernel_samsung_universal7885
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[PATCH] ufs: ufs_get_locked_page() race fix

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As discussed earlier:
http://lkml.org/lkml/2006/6/28/136
this patch fixes such issue:

`ufs_get_locked_page' takes page from cache
after that `vmtruncate' takes page and deletes it from cache
`ufs_get_locked_page' locks page, and reports about EIO error.

Also because of find_lock_page always return valid page or NULL, we have no
need to check it if page not NULL.

Signed-off-by: Evgeniy Dushistov <dushistov@mail.ru>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
Evgeniy Dushistov 2006-08-05 12:13:55 -07:00 committed by Linus Torvalds
parent e91467ecd1
commit 1fb32b7bd8
1 changed files with 8 additions and 7 deletions
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15
fs/ufs/util.c
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@ -257,6 +257,7 @@ try_again:
page = read_cache_page(mapping, index, page = read_cache_page(mapping, index,
(filler_t*)mapping->a_ops->readpage, (filler_t*)mapping->a_ops->readpage,
NULL); NULL);
if (IS_ERR(page)) { if (IS_ERR(page)) {
printk(KERN_ERR "ufs_change_blocknr: " printk(KERN_ERR "ufs_change_blocknr: "
"read_cache_page error: ino %lu, index: %lu\n", "read_cache_page error: ino %lu, index: %lu\n",
@ -266,6 +267,13 @@ try_again:
lock_page(page); lock_page(page);
if (unlikely(page->mapping == NULL)) {
/* Truncate got there first */
unlock_page(page);
page_cache_release(page);
goto try_again;
}
if (!PageUptodate(page) || PageError(page)) { if (!PageUptodate(page) || PageError(page)) {
unlock_page(page); unlock_page(page);
page_cache_release(page); page_cache_release(page);
@ -275,15 +283,8 @@ try_again:
mapping->host->i_ino, index); mapping->host->i_ino, index);
page = ERR_PTR(-EIO); page = ERR_PTR(-EIO);
goto out;
} }
} }
if (unlikely(!page->mapping || !page_has_buffers(page))) {
unlock_page(page);
page_cache_release(page);
goto try_again;/*we really need these buffers*/
}
out: out:
return page; return page;
} }