diff options
Diffstat (limited to 'ext4-fix-races-between-buffered-IO-and-collapse-inse.patch')
| -rw-r--r-- | ext4-fix-races-between-buffered-IO-and-collapse-inse.patch | 119 |
1 files changed, 0 insertions, 119 deletions
diff --git a/ext4-fix-races-between-buffered-IO-and-collapse-inse.patch b/ext4-fix-races-between-buffered-IO-and-collapse-inse.patch deleted file mode 100644 index 0c89ea77a..000000000 --- a/ext4-fix-races-between-buffered-IO-and-collapse-inse.patch +++ /dev/null @@ -1,119 +0,0 @@ -From 32ebffd3bbb4162da5ff88f9a35dd32d0a28ea70 Mon Sep 17 00:00:00 2001 -From: Jan Kara <jack@suse.com> -Date: Mon, 7 Dec 2015 14:31:11 -0500 -Subject: [PATCH 3/4] ext4: fix races between buffered IO and collapse / insert - range - -Current code implementing FALLOC_FL_COLLAPSE_RANGE and -FALLOC_FL_INSERT_RANGE is prone to races with buffered writes and page -faults. If buffered write or write via mmap manages to squeeze between -filemap_write_and_wait_range() and truncate_pagecache() in the fallocate -implementations, the written data is simply discarded by -truncate_pagecache() although it should have been shifted. - -Fix the problem by moving filemap_write_and_wait_range() call inside -i_mutex and i_mmap_sem. That way we are protected against races with -both buffered writes and page faults. - -Signed-off-by: Jan Kara <jack@suse.com> -Signed-off-by: Theodore Ts'o <tytso@mit.edu> ---- - fs/ext4/extents.c | 59 +++++++++++++++++++++++++++++-------------------------- - 1 file changed, 31 insertions(+), 28 deletions(-) - -diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c -index 65b5ada2833f..4b105c96df08 100644 ---- a/fs/ext4/extents.c -+++ b/fs/ext4/extents.c -@@ -5487,21 +5487,7 @@ int ext4_collapse_range(struct inode *inode, loff_t offset, loff_t len) - return ret; - } - -- /* -- * Need to round down offset to be aligned with page size boundary -- * for page size > block size. -- */ -- ioffset = round_down(offset, PAGE_SIZE); -- -- /* Write out all dirty pages */ -- ret = filemap_write_and_wait_range(inode->i_mapping, ioffset, -- LLONG_MAX); -- if (ret) -- return ret; -- -- /* Take mutex lock */ - mutex_lock(&inode->i_mutex); -- - /* - * There is no need to overlap collapse range with EOF, in which case - * it is effectively a truncate operation -@@ -5526,6 +5512,27 @@ int ext4_collapse_range(struct inode *inode, loff_t offset, loff_t len) - * page cache. - */ - down_write(&EXT4_I(inode)->i_mmap_sem); -+ /* -+ * Need to round down offset to be aligned with page size boundary -+ * for page size > block size. -+ */ -+ ioffset = round_down(offset, PAGE_SIZE); -+ /* -+ * Write tail of the last page before removed range since it will get -+ * removed from the page cache below. -+ */ -+ ret = filemap_write_and_wait_range(inode->i_mapping, ioffset, offset); -+ if (ret) -+ goto out_mmap; -+ /* -+ * Write data that will be shifted to preserve them when discarding -+ * page cache below. We are also protected from pages becoming dirty -+ * by i_mmap_sem. -+ */ -+ ret = filemap_write_and_wait_range(inode->i_mapping, offset + len, -+ LLONG_MAX); -+ if (ret) -+ goto out_mmap; - truncate_pagecache(inode, ioffset); - - credits = ext4_writepage_trans_blocks(inode); -@@ -5626,21 +5633,7 @@ int ext4_insert_range(struct inode *inode, loff_t offset, loff_t len) - return ret; - } - -- /* -- * Need to round down to align start offset to page size boundary -- * for page size > block size. -- */ -- ioffset = round_down(offset, PAGE_SIZE); -- -- /* Write out all dirty pages */ -- ret = filemap_write_and_wait_range(inode->i_mapping, ioffset, -- LLONG_MAX); -- if (ret) -- return ret; -- -- /* Take mutex lock */ - mutex_lock(&inode->i_mutex); -- - /* Currently just for extent based files */ - if (!ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) { - ret = -EOPNOTSUPP; -@@ -5668,6 +5661,16 @@ int ext4_insert_range(struct inode *inode, loff_t offset, loff_t len) - * page cache. - */ - down_write(&EXT4_I(inode)->i_mmap_sem); -+ /* -+ * Need to round down to align start offset to page size boundary -+ * for page size > block size. -+ */ -+ ioffset = round_down(offset, PAGE_SIZE); -+ /* Write out all dirty pages */ -+ ret = filemap_write_and_wait_range(inode->i_mapping, ioffset, -+ LLONG_MAX); -+ if (ret) -+ goto out_mmap; - truncate_pagecache(inode, ioffset); - - credits = ext4_writepage_trans_blocks(inode); --- -2.5.5 - |