diff options
| author | Xiubo Li <xiubli@redhat.com> | 2022-07-11 12:11:21 +0800 |
|---|---|---|
| committer | Ilya Dryomov <idryomov@gmail.com> | 2022-07-14 10:10:12 +0200 |
| commit | fac47b43c760ea90e64b895dba60df0327be7775 (patch) | |
| tree | ce9fe5b54a150c80acf4683288924f94a6b5cfc8 /Documentation | |
| parent | 32346491ddf24599decca06190ebca03ff9de7f8 (diff) | |
netfs: do not unlock and put the folio twice
check_write_begin() will unlock and put the folio when return
non-zero. So we should avoid unlocking and putting it twice in
netfs layer.
Change the way ->check_write_begin() works in the following two ways:
(1) Pass it a pointer to the folio pointer, allowing it to unlock and put
the folio prior to doing the stuff it wants to do, provided it clears
the folio pointer.
(2) Change the return values such that 0 with folio pointer set means
continue, 0 with folio pointer cleared means re-get and all error
codes indicating an error (no special treatment for -EAGAIN).
[ bagasdotme: use Sphinx code text syntax for *foliop pointer ]
Cc: stable@vger.kernel.org
Link: https://tracker.ceph.com/issues/56423
Link: https://lore.kernel.org/r/cf169f43-8ee7-8697-25da-0204d1b4343e@redhat.com
Co-developed-by: David Howells <dhowells@redhat.com>
Signed-off-by: Xiubo Li <xiubli@redhat.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Bagas Sanjaya <bagasdotme@gmail.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/filesystems/netfs_library.rst | 8 |
1 files changed, 5 insertions, 3 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`` |