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-rw-r--r--Documentation/filesystems/netfs_library.rst8
-rw-r--r--fs/afs/file.c2
-rw-r--r--fs/ceph/addr.c11
-rw-r--r--fs/netfs/buffered_read.c17
-rw-r--r--include/linux/netfs.h2
5 files changed, 23 insertions, 17 deletions
diff --git a/Documentation/filesystems/netfs_library.rst b/Documentation/filesystems/netfs_library.rst
index 4d19b19bcc08..73a4176144b3 100644
--- a/Documentation/filesystems/netfs_library.rst
+++ b/Documentation/filesystems/netfs_library.rst
@@ -301,7 +301,7 @@ through which it can issue requests and negotiate::
void (*issue_read)(struct netfs_io_subrequest *subreq);
bool (*is_still_valid)(struct netfs_io_request *rreq);
int (*check_write_begin)(struct file *file, loff_t pos, unsigned len,
- struct folio *folio, void **_fsdata);
+ struct folio **foliop, void **_fsdata);
void (*done)(struct netfs_io_request *rreq);
};
@@ -381,8 +381,10 @@ The operations are as follows:
allocated/grabbed the folio to be modified to allow the filesystem to flush
conflicting state before allowing it to be modified.
- It should return 0 if everything is now fine, -EAGAIN if the folio should be
- regrabbed and any other error code to abort the operation.
+ It may unlock and discard the folio it was given and set the caller's folio
+ pointer to NULL. It should return 0 if everything is now fine (``*foliop``
+ left set) or the op should be retried (``*foliop`` cleared) and any other
+ error code to abort the operation.
* ``done``
diff --git a/fs/afs/file.c b/fs/afs/file.c
index 42118a4f3383..d1cfb235c4b9 100644
--- a/fs/afs/file.c
+++ b/fs/afs/file.c
@@ -375,7 +375,7 @@ static int afs_begin_cache_operation(struct netfs_io_request *rreq)
}
static int afs_check_write_begin(struct file *file, loff_t pos, unsigned len,
- struct folio *folio, void **_fsdata)
+ struct folio **foliop, void **_fsdata)
{
struct afs_vnode *vnode = AFS_FS_I(file_inode(file));
diff --git a/fs/ceph/addr.c b/fs/ceph/addr.c
index 6dee88815491..d6e5916138e4 100644
--- a/fs/ceph/addr.c
+++ b/fs/ceph/addr.c
@@ -63,7 +63,7 @@
(CONGESTION_ON_THRESH(congestion_kb) >> 2))
static int ceph_netfs_check_write_begin(struct file *file, loff_t pos, unsigned int len,
- struct folio *folio, void **_fsdata);
+ struct folio **foliop, void **_fsdata);
static inline struct ceph_snap_context *page_snap_context(struct page *page)
{
@@ -1288,18 +1288,19 @@ ceph_find_incompatible(struct page *page)
}
static int ceph_netfs_check_write_begin(struct file *file, loff_t pos, unsigned int len,
- struct folio *folio, void **_fsdata)
+ struct folio **foliop, void **_fsdata)
{
struct inode *inode = file_inode(file);
struct ceph_inode_info *ci = ceph_inode(inode);
struct ceph_snap_context *snapc;
- snapc = ceph_find_incompatible(folio_page(folio, 0));
+ snapc = ceph_find_incompatible(folio_page(*foliop, 0));
if (snapc) {
int r;
- folio_unlock(folio);
- folio_put(folio);
+ folio_unlock(*foliop);
+ folio_put(*foliop);
+ *foliop = NULL;
if (IS_ERR(snapc))
return PTR_ERR(snapc);
diff --git a/fs/netfs/buffered_read.c b/fs/netfs/buffered_read.c
index 42f892c5712e..0ce535852151 100644
--- a/fs/netfs/buffered_read.c
+++ b/fs/netfs/buffered_read.c
@@ -319,8 +319,9 @@ zero_out:
* conflicting writes once the folio is grabbed and locked. It is passed a
* pointer to the fsdata cookie that gets returned to the VM to be passed to
* write_end. It is permitted to sleep. It should return 0 if the request
- * should go ahead; unlock the folio and return -EAGAIN to cause the folio to
- * be regot; or return an error.
+ * should go ahead or it may return an error. It may also unlock and put the
+ * folio, provided it sets ``*foliop`` to NULL, in which case a return of 0
+ * will cause the folio to be re-got and the process to be retried.
*
* The calling netfs must initialise a netfs context contiguous to the vfs
* inode before calling this.
@@ -348,13 +349,13 @@ retry:
if (ctx->ops->check_write_begin) {
/* Allow the netfs (eg. ceph) to flush conflicts. */
- ret = ctx->ops->check_write_begin(file, pos, len, folio, _fsdata);
+ ret = ctx->ops->check_write_begin(file, pos, len, &folio, _fsdata);
if (ret < 0) {
trace_netfs_failure(NULL, NULL, ret, netfs_fail_check_write_begin);
- if (ret == -EAGAIN)
- goto retry;
goto error;
}
+ if (!folio)
+ goto retry;
}
if (folio_test_uptodate(folio))
@@ -416,8 +417,10 @@ have_folio_no_wait:
error_put:
netfs_put_request(rreq, false, netfs_rreq_trace_put_failed);
error:
- folio_unlock(folio);
- folio_put(folio);
+ if (folio) {
+ folio_unlock(folio);
+ folio_put(folio);
+ }
_leave(" = %d", ret);
return ret;
}
diff --git a/include/linux/netfs.h b/include/linux/netfs.h
index 1773e5df8e65..1b18dfa52e48 100644
--- a/include/linux/netfs.h
+++ b/include/linux/netfs.h
@@ -214,7 +214,7 @@ struct netfs_request_ops {
void (*issue_read)(struct netfs_io_subrequest *subreq);
bool (*is_still_valid)(struct netfs_io_request *rreq);
int (*check_write_begin)(struct file *file, loff_t pos, unsigned len,
- struct folio *folio, void **_fsdata);
+ struct folio **foliop, void **_fsdata);
void (*done)(struct netfs_io_request *rreq);
};