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| author | Liu Bo <bo.li.liu@oracle.com> | 2016-07-11 10:39:07 -0700 |
|---|---|---|
| committer | David Sterba <dsterba@suse.com> | 2016-07-26 13:52:25 +0200 |
| commit | baf863b9c29617cc9eaf24e039f58846e700db48 (patch) | |
| tree | 916fe6a7c3967160de5d6d991dd6e1088953add8 /fs | |
| parent | f49070957ffed84feb7944550f7edd53672b5201 (diff) | |
| download | linux-baf863b9c29617cc9eaf24e039f58846e700db48.tar.bz2 | |
Btrfs: fix eb memory leak due to readpage failure
eb->io_pages is set in read_extent_buffer_pages().
In case of readpage failure, for pages that have been added to bio,
it calls bio_endio and later readpage_io_failed_hook() does the work.
When this eb's page (couldn't be the 1st page) fails to add itself to bio
due to failure in merge_bio(), it cannot decrease eb->io_pages via bio_endio,
and ends up with a memory leak eventually.
This lets __do_readpage propagate errors to callers and adds the
'atomic_dec(&eb->io_pages)'.
Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/btrfs/extent_io.c | 25 |
1 files changed, 22 insertions, 3 deletions
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c index ea12d0ee684f..dae2f8470e04 100644 --- a/fs/btrfs/extent_io.c +++ b/fs/btrfs/extent_io.c @@ -2878,6 +2878,7 @@ __get_extent_map(struct inode *inode, struct page *page, size_t pg_offset, * into the tree that are removed when the IO is done (by the end_io * handlers) * XXX JDM: This needs looking at to ensure proper page locking + * return 0 on success, otherwise return error */ static int __do_readpage(struct extent_io_tree *tree, struct page *page, @@ -2899,7 +2900,7 @@ static int __do_readpage(struct extent_io_tree *tree, sector_t sector; struct extent_map *em; struct block_device *bdev; - int ret; + int ret = 0; int nr = 0; size_t pg_offset = 0; size_t iosize; @@ -3080,6 +3081,7 @@ static int __do_readpage(struct extent_io_tree *tree, } else { SetPageError(page); unlock_extent(tree, cur, cur + iosize - 1); + goto out; } cur = cur + iosize; pg_offset += iosize; @@ -3090,7 +3092,7 @@ out: SetPageUptodate(page); unlock_page(page); } - return 0; + return ret; } static inline void __do_contiguous_readpages(struct extent_io_tree *tree, @@ -5230,14 +5232,31 @@ int read_extent_buffer_pages(struct extent_io_tree *tree, atomic_set(&eb->io_pages, num_reads); for (i = start_i; i < num_pages; i++) { page = eb->pages[i]; + if (!PageUptodate(page)) { + if (ret) { + atomic_dec(&eb->io_pages); + unlock_page(page); + continue; + } + ClearPageError(page); err = __extent_read_full_page(tree, page, get_extent, &bio, mirror_num, &bio_flags, READ | REQ_META); - if (err) + if (err) { ret = err; + /* + * We use &bio in above __extent_read_full_page, + * so we ensure that if it returns error, the + * current page fails to add itself to bio and + * it's been unlocked. + * + * We must dec io_pages by ourselves. + */ + atomic_dec(&eb->io_pages); + } } else { unlock_page(page); } |