82  * Returns if the folio has dirty or writeback buffers. If all the buffers
84  * any of the buffers are locked, it is assumed they are locked for IO.
180  * But it's the page lock which protects the buffers.  To get around this,
222 	/* we might be here because some of the buffers on this page are  in __find_get_block_slow()
225 	 * elsewhere, don't buffer_error if we had some unmapped buffers  in __find_get_block_slow()
285 	 * If all of the buffers are uptodate then we can set the page  in end_buffer_async_read()
385  * If a page's buffers are under async readin (end_buffer_async_read
387  * control could lock one of the buffers after it has completed
388  * but while some of the other buffers have not completed.  This
393  * The page comes unlocked when it has no locked buffer_async buffers
397  * the buffers.
434  * management of a list of dependent buffers at ->i_mapping->private_list.
436  * Locking is a little subtle: try_to_free_buffers() will remove buffers
439  * at the time, not against the S_ISREG file which depends on those buffers.
441  * which backs the buffers.  Which is different from the address_space 
442  * against which the buffers are listed.  So for a particular address_space,
447  * Which introduces a requirement: all buffers on an address_space's
450  * address_spaces which do not place buffers at ->private_list via these
461  * mark_buffer_dirty_fsync() to clearly define why those buffers are being
468  * that buffers are taken *off* the old inode's list when they are freed
495  * as you dirty the buffers, and then use osync_inode_buffers to wait for
496  * completion.  Any other dirty buffers which are not yet queued for
531  * sync_mapping_buffers - write out & wait upon a mapping's "associated" buffers
532  * @mapping: the mapping which wants those buffers written
534  * Starts I/O against the buffers at mapping->private_list, and waits upon
538  * @mapping is a file or directory which needs those buffers to be written for
597  * If the page has buffers, the uptodate buffers are set dirty, to preserve
598  * dirty-state coherency between the page and the buffers.  It the page does
599  * not have buffers then when they are later attached they will all be set
602  * The buffers are dirtied before the page is dirtied.  There's a small race
605  * before the buffers, a concurrent writepage caller could clear the page dirty
606  * bit, see a bunch of clean buffers and we'd end up with dirty buffers/clean
610  * page's buffer list.  Also use this to protect against clean buffers being
652  * Write out and wait upon a list of buffers.
655  * initially dirty buffers get waited on, but that any subsequently
656  * dirtied buffers don't.  After all, we don't want fsync to last
659  * Do this in two main stages: first we copy dirty buffers to a
667  * the osync code to catch these locked, dirty buffers without requeuing
668  * any newly dirty buffers for write.
750  * Invalidate any and all dirty buffers on a given inode.  We are
752  * done a sync().  Just drop the buffers from the inode list.
755  * assumes that all the buffers are against the blockdev.  Not true
774  * Remove any clean buffers from the inode's buffer list.  This is called
775  * when we're trying to free the inode itself.  Those buffers can pin it.
777  * Returns true if all buffers were removed.
803  * Create the appropriate buffers when given a page for data area and
805  * follow the buffers created.  Return NULL if unable to create more
806  * buffers.
888  * Initialise the state of a blockdev page's buffers.
963 	 * Allocate some buffers for this page  in grow_dev_page()
968 	 * Link the page to the buffers and initialise them.  Take the  in grow_dev_page()
986  * Create buffers for the specified block device block's page.  If
987  * that page was dirty, the buffers are set dirty also.
1010 	/* Create a page with the proper size buffers.. */  in grow_buffers()
1045  * The relationship between dirty buffers and dirty pages:
1047  * Whenever a page has any dirty buffers, the page's dirty bit is set, and
1050  * At all times, the dirtiness of the buffers represents the dirtiness of
1051  * subsections of the page.  If the page has buffers, the page dirty bit is
1054  * When a page is set dirty in its entirety, all its buffers are marked dirty
1055  * (if the page has buffers).
1058  * buffers are not.
1060  * Also.  When blockdev buffers are explicitly read with bread(), they
1062  * uptodate - even if all of its buffers are uptodate.  A subsequent
1064  * buffers, will set the folio uptodate and will perform no I/O.
1133  * Decrement a buffer_head's reference count.  If all buffers against a page
1135  * and unlocked then try_to_free_buffers() may strip the buffers from the page
1136  * in preparation for freeing it (sometimes, rarely, buffers are removed from
1137  * a page but it ends up not being freed, and buffers may later be reattached).
1188  * The bhs[] array is sorted - newest buffer is at bhs[0].  Buffers have their
1477  * block_invalidate_folio() does not have to release all buffers, but it must
1521 	 * We release buffers only if the entire folio is being invalidated.  in block_invalidate_folio()
1534  * We attach and possibly dirty the buffers atomically wrt
1569  * clean_bdev_aliases: clean a range of buffers in block device
1570  * @bdev: Block device to clean buffers in
1584  * writeout I/O going on against recently-freed buffers.  We don't wait on that
1610 			 * to pin buffers here since we can afford to sleep and  in clean_bdev_aliases()
1679  * While block_write_full_page is writing back the dirty buffers under
1680  * the page lock, whoever dirtied the buffers may decide to clean them
1711 	 * here, and the (potentially unmapped) buffers may become dirty at  in __block_write_full_page()
1715 	 * Buffers outside i_size may be dirtied by block_dirty_folio;  in __block_write_full_page()
1727 	 * Get all the dirty buffers mapped to disk addresses and  in __block_write_full_page()
1733 			 * mapped buffers outside i_size will occur, because  in __block_write_full_page()
1783 	 * The page and its buffers are protected by PageWriteback(), so we can  in __block_write_full_page()
1803 		 * The page was marked dirty, but the buffers were  in __block_write_full_page()
1824 	/* Recovery: lock and submit the mapped buffers */  in __block_write_full_page()
1857  * If a page has any new buffers, zero them out here, and mark them uptodate
2075 	 * If this is a partial write which happened to make all buffers  in __block_commit_write()
2125 		 * The buffers that were written will now be uptodate, so  in block_write_end()
2190  * block_is_partially_uptodate checks whether buffers within a folio are
2193  * Returns true if all buffers which correspond to the specified part
2299 		 * All buffers are uptodate - we can set the folio uptodate  in block_read_full_folio()
2308 	/* Stage two: lock the buffers */  in block_read_full_folio()
2763  * try_to_free_buffers() checks if all the buffers on this particular folio
2769  * If the folio is dirty but all the buffers are clean then we need to
2771  * may be against a block device, and a later reattachment of buffers
2772  * to a dirty folio will set *all* buffers dirty.  Which would corrupt
2775  * The same applies to regular filesystem folios: if all the buffers are
2834 	 * If the filesystem writes its buffers by hand (eg ext3)  in try_to_free_buffers()
2835 	 * then we can have clean buffers against a dirty folio.  We  in try_to_free_buffers()
2840 	 * the folio's buffers clean.  We discover that here and clean  in try_to_free_buffers()
2983  * __bh_read_batch - Submit read for a batch of unlocked buffers