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authorLinus Torvalds <torvalds@linux-foundation.org>2020-07-10 08:53:21 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2020-07-10 08:53:21 -0700
commitd02b0478c1acb00e9d9ee40810627eba5745d94b (patch)
tree9c522f00c574d8641c0242dd606ac30ea7909582 /fs
parentf4c8824cbcc64524905f83388eb1139747829756 (diff)
parent20f829999c38b18e3d17f9e40dea3a28f721fac4 (diff)
downloadlinux-d02b0478c1acb00e9d9ee40810627eba5745d94b.tar.bz2
Merge tag 'gfs2-v5.8-rc4.fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/gfs2/linux-gfs2
Pull gfs2 fixes from Andreas Gruenbacher: "Fix gfs2 readahead deadlocks by adding a IOCB_NOIO flag that allows gfs2 to use the generic fiel read iterator functions without having to worry about being called back while holding locks". * tag 'gfs2-v5.8-rc4.fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/gfs2/linux-gfs2: gfs2: Rework read and page fault locking fs: Add IOCB_NOIO flag for generic_file_read_iter
Diffstat (limited to 'fs')
-rw-r--r--fs/gfs2/aops.c45
-rw-r--r--fs/gfs2/file.c52
2 files changed, 51 insertions, 46 deletions
diff --git a/fs/gfs2/aops.c b/fs/gfs2/aops.c
index 72c9560f4467..68cd700a2719 100644
--- a/fs/gfs2/aops.c
+++ b/fs/gfs2/aops.c
@@ -468,21 +468,10 @@ static int stuffed_readpage(struct gfs2_inode *ip, struct page *page)
}
-/**
- * __gfs2_readpage - readpage
- * @file: The file to read a page for
- * @page: The page to read
- *
- * This is the core of gfs2's readpage. It's used by the internal file
- * reading code as in that case we already hold the glock. Also it's
- * called by gfs2_readpage() once the required lock has been granted.
- */
-
static int __gfs2_readpage(void *file, struct page *page)
{
struct gfs2_inode *ip = GFS2_I(page->mapping->host);
struct gfs2_sbd *sdp = GFS2_SB(page->mapping->host);
-
int error;
if (i_blocksize(page->mapping->host) == PAGE_SIZE &&
@@ -505,36 +494,11 @@ static int __gfs2_readpage(void *file, struct page *page)
* gfs2_readpage - read a page of a file
* @file: The file to read
* @page: The page of the file
- *
- * This deals with the locking required. We have to unlock and
- * relock the page in order to get the locking in the right
- * order.
*/
static int gfs2_readpage(struct file *file, struct page *page)
{
- struct address_space *mapping = page->mapping;
- struct gfs2_inode *ip = GFS2_I(mapping->host);
- struct gfs2_holder gh;
- int error;
-
- unlock_page(page);
- gfs2_holder_init(ip->i_gl, LM_ST_SHARED, 0, &gh);
- error = gfs2_glock_nq(&gh);
- if (unlikely(error))
- goto out;
- error = AOP_TRUNCATED_PAGE;
- lock_page(page);
- if (page->mapping == mapping && !PageUptodate(page))
- error = __gfs2_readpage(file, page);
- else
- unlock_page(page);
- gfs2_glock_dq(&gh);
-out:
- gfs2_holder_uninit(&gh);
- if (error && error != AOP_TRUNCATED_PAGE)
- lock_page(page);
- return error;
+ return __gfs2_readpage(file, page);
}
/**
@@ -598,16 +562,9 @@ static void gfs2_readahead(struct readahead_control *rac)
{
struct inode *inode = rac->mapping->host;
struct gfs2_inode *ip = GFS2_I(inode);
- struct gfs2_holder gh;
- gfs2_holder_init(ip->i_gl, LM_ST_SHARED, 0, &gh);
- if (gfs2_glock_nq(&gh))
- goto out_uninit;
if (!gfs2_is_stuffed(ip))
mpage_readahead(rac, gfs2_block_map);
- gfs2_glock_dq(&gh);
-out_uninit:
- gfs2_holder_uninit(&gh);
}
/**
diff --git a/fs/gfs2/file.c b/fs/gfs2/file.c
index fe305e4bfd37..bebde537ac8c 100644
--- a/fs/gfs2/file.c
+++ b/fs/gfs2/file.c
@@ -558,8 +558,29 @@ out_uninit:
return block_page_mkwrite_return(ret);
}
+static vm_fault_t gfs2_fault(struct vm_fault *vmf)
+{
+ struct inode *inode = file_inode(vmf->vma->vm_file);
+ struct gfs2_inode *ip = GFS2_I(inode);
+ struct gfs2_holder gh;
+ vm_fault_t ret;
+ int err;
+
+ gfs2_holder_init(ip->i_gl, LM_ST_SHARED, 0, &gh);
+ err = gfs2_glock_nq(&gh);
+ if (err) {
+ ret = block_page_mkwrite_return(err);
+ goto out_uninit;
+ }
+ ret = filemap_fault(vmf);
+ gfs2_glock_dq(&gh);
+out_uninit:
+ gfs2_holder_uninit(&gh);
+ return ret;
+}
+
static const struct vm_operations_struct gfs2_vm_ops = {
- .fault = filemap_fault,
+ .fault = gfs2_fault,
.map_pages = filemap_map_pages,
.page_mkwrite = gfs2_page_mkwrite,
};
@@ -824,6 +845,9 @@ out_uninit:
static ssize_t gfs2_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
{
+ struct gfs2_inode *ip;
+ struct gfs2_holder gh;
+ size_t written = 0;
ssize_t ret;
if (iocb->ki_flags & IOCB_DIRECT) {
@@ -832,7 +856,31 @@ static ssize_t gfs2_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
return ret;
iocb->ki_flags &= ~IOCB_DIRECT;
}
- return generic_file_read_iter(iocb, to);
+ iocb->ki_flags |= IOCB_NOIO;
+ ret = generic_file_read_iter(iocb, to);
+ iocb->ki_flags &= ~IOCB_NOIO;
+ if (ret >= 0) {
+ if (!iov_iter_count(to))
+ return ret;
+ written = ret;
+ } else {
+ if (ret != -EAGAIN)
+ return ret;
+ if (iocb->ki_flags & IOCB_NOWAIT)
+ return ret;
+ }
+ ip = GFS2_I(iocb->ki_filp->f_mapping->host);
+ gfs2_holder_init(ip->i_gl, LM_ST_SHARED, 0, &gh);
+ ret = gfs2_glock_nq(&gh);
+ if (ret)
+ goto out_uninit;
+ ret = generic_file_read_iter(iocb, to);
+ if (ret > 0)
+ written += ret;
+ gfs2_glock_dq(&gh);
+out_uninit:
+ gfs2_holder_uninit(&gh);
+ return written ? written : ret;
}
/**