@@ -1024,8 +1024,7 @@ could be on demand. For example wait_on_buffer sets the unplugging going
through sync_buffer() running blk_run_address_space(mapping). Or the caller
can do it explicity through blk_unplug(bdev). So in the read case,
the queue gets explicitly unplugged as part of waiting for completion on that
-buffer. For page driven IO, the address space ->sync_page() takes care of
-doing the blk_run_address_space().
+buffer.
Aside:
This is kind of controversial territory, as it's not clear if plugging is
@@ -179,7 +179,6 @@ unlocks and drops the reference.
prototypes:
int (*writepage)(struct page *page, struct writeback_control *wbc);
int (*readpage)(struct file *, struct page *);
- int (*sync_page)(struct page *);
int (*writepages)(struct address_space *, struct writeback_control *);
int (*set_page_dirty)(struct page *page);
int (*readpages)(struct file *filp, struct address_space *mapping,
@@ -208,7 +207,6 @@ locking rules:
PageLocked(page) i_mutex
writepage: yes, unlocks (see below)
readpage: yes, unlocks
-sync_page: maybe
writepages:
set_page_dirty no
readpages:
@@ -226,8 +224,8 @@ error_remove_page: yes
swap_activate: no
swap_deactivate: no
- ->write_begin(), ->write_end(), ->sync_page() and ->readpage()
-may be called from the request handler (/dev/loop).
+ ->write_begin(), ->write_end() and ->readpage() may be called from
+the request handler (/dev/loop).
->readpage() unlocks the page, either synchronously or via I/O
completion.
@@ -283,11 +281,6 @@ will leave the page itself marked clean but it will be tagged as dirty in the
radix tree. This incoherency can lead to all sorts of hard-to-debug problems
in the filesystem like having dirty inodes at umount and losing written data.
- ->sync_page() locking rules are not well-defined - usually it is called
-with lock on page, but that is not guaranteed. Considering the currently
-existing instances of this method ->sync_page() itself doesn't look
-well-defined...
-
->writepages() is used for periodic writeback and for syscall-initiated
sync operations. The address_space should start I/O against at least
*nr_to_write pages. *nr_to_write must be decremented for each page which is
@@ -534,9 +534,7 @@ __sync_single_inode) to check if ->writepages has been successful in
writing out the whole address_space.
The Writeback tag is used by filemap*wait* and sync_page* functions,
-via filemap_fdatawait_range, to wait for all writeback to
-complete. While waiting ->sync_page (if defined) will be called on
-each page that is found to require writeback.
+via filemap_fdatawait_range, to wait for all writeback to complete.
An address_space handler may attach extra information to a page,
typically using the 'private' field in the 'struct page'. If such
@@ -554,8 +552,8 @@ address_space has finer control of write sizes.
The read process essentially only requires 'readpage'. The write
process is more complicated and uses write_begin/write_end or
-set_page_dirty to write data into the address_space, and writepage,
-sync_page, and writepages to writeback data to storage.
+set_page_dirty to write data into the address_space, and writepage
+and writepages to writeback data to storage.
Adding and removing pages to/from an address_space is protected by the
inode's i_mutex.
@@ -361,7 +361,6 @@ static int zisofs_readpage(struct file *file, struct page *page)
const struct address_space_operations zisofs_aops = {
.readpage = zisofs_readpage,
- /* No sync_page operation supported? */
/* No bmap operation supported */
};
@@ -1854,7 +1854,7 @@ int ntfs_read_inode_mount(struct inode *vi)
/* Need this to sanity check attribute list references to $MFT. */
vi->i_generation = ni->seq_no = le16_to_cpu(m->sequence_number);
- /* Provides readpage() and sync_page() for map_mft_record(). */
+ /* Provides readpage() for map_mft_record(). */
vi->i_mapping->a_ops = &ntfs_mst_aops;
ctx = ntfs_attr_get_search_ctx(ni, m);
Commit 7eaceaccab5f removed ->sync_page, but a few mentions of it still existed in documentation and comments, Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com> --- Documentation/block/biodoc.txt | 3 +-- Documentation/filesystems/Locking | 11 ++--------- Documentation/filesystems/vfs.txt | 8 +++----- fs/isofs/compress.c | 1 - fs/ntfs/inode.c | 2 +- 5 files changed, 7 insertions(+), 18 deletions(-)