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author | Mark Fasheh <mark.fasheh@oracle.com> | 2006-05-06 02:04:03 (GMT) |
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committer | Mark Fasheh <mark.fasheh@oracle.com> | 2006-05-17 21:38:47 (GMT) |
commit | 53013cba4118a5cfe8f7c7ea5e5bc1c48b160f76 (patch) | |
tree | 5170ed12fbe07b5e8557e61952aa27c25034bd7a /fs/ocfs2/aops.c | |
parent | 0c056c50a6218e0e577817c16ba8851af593d742 (diff) | |
download | linux-fsl-qoriq-53013cba4118a5cfe8f7c7ea5e5bc1c48b160f76.tar.xz |
ocfs2: take data locks around extend
We need to take a data lock around extends to protect the pages that
ocfs2_zero_extend is going to be pulling into the page cache. Otherwise an
extend on one node might populate the page cache with data pages that have
no lock coverage.
Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>
Diffstat (limited to 'fs/ocfs2/aops.c')
-rw-r--r-- | fs/ocfs2/aops.c | 46 |
1 files changed, 39 insertions, 7 deletions
diff --git a/fs/ocfs2/aops.c b/fs/ocfs2/aops.c index 0d858d0..47152bf 100644 --- a/fs/ocfs2/aops.c +++ b/fs/ocfs2/aops.c @@ -276,13 +276,29 @@ static int ocfs2_writepage(struct page *page, struct writeback_control *wbc) return ret; } +/* This can also be called from ocfs2_write_zero_page() which has done + * it's own cluster locking. */ +int ocfs2_prepare_write_nolock(struct inode *inode, struct page *page, + unsigned from, unsigned to) +{ + int ret; + + down_read(&OCFS2_I(inode)->ip_alloc_sem); + + ret = block_prepare_write(page, from, to, ocfs2_get_block); + + up_read(&OCFS2_I(inode)->ip_alloc_sem); + + return ret; +} + /* * ocfs2_prepare_write() can be an outer-most ocfs2 call when it is called * from loopback. It must be able to perform its own locking around * ocfs2_get_block(). */ -int ocfs2_prepare_write(struct file *file, struct page *page, - unsigned from, unsigned to) +static int ocfs2_prepare_write(struct file *file, struct page *page, + unsigned from, unsigned to) { struct inode *inode = page->mapping->host; int ret; @@ -295,11 +311,7 @@ int ocfs2_prepare_write(struct file *file, struct page *page, goto out; } - down_read(&OCFS2_I(inode)->ip_alloc_sem); - - ret = block_prepare_write(page, from, to, ocfs2_get_block); - - up_read(&OCFS2_I(inode)->ip_alloc_sem); + ret = ocfs2_prepare_write_nolock(inode, page, from, to); ocfs2_meta_unlock(inode, 0); out: @@ -625,11 +637,31 @@ static ssize_t ocfs2_direct_IO(int rw, int ret; mlog_entry_void(); + + /* + * We get PR data locks even for O_DIRECT. This allows + * concurrent O_DIRECT I/O but doesn't let O_DIRECT with + * extending and buffered zeroing writes race. If they did + * race then the buffered zeroing could be written back after + * the O_DIRECT I/O. It's one thing to tell people not to mix + * buffered and O_DIRECT writes, but expecting them to + * understand that file extension is also an implicit buffered + * write is too much. By getting the PR we force writeback of + * the buffered zeroing before proceeding. + */ + ret = ocfs2_data_lock(inode, 0); + if (ret < 0) { + mlog_errno(ret); + goto out; + } + ocfs2_data_unlock(inode, 0); + ret = blockdev_direct_IO_no_locking(rw, iocb, inode, inode->i_sb->s_bdev, iov, offset, nr_segs, ocfs2_direct_IO_get_blocks, ocfs2_dio_end_io); +out: mlog_exit(ret); return ret; } |