forked from Minki/linux
4e96b2dbbf
This patch adds two new routines: ext4_discard_partial_page_buffers and ext4_discard_partial_page_buffers_no_lock. The ext4_discard_partial_page_buffers routine is a wrapper function to ext4_discard_partial_page_buffers_no_lock. The wrapper function locks the page and passes it to ext4_discard_partial_page_buffers_no_lock. Calling functions that already have the page locked can call ext4_discard_partial_page_buffers_no_lock directly. The ext4_discard_partial_page_buffers_no_lock function zeros a specified range in a page, and unmaps the corresponding buffer heads. Only block aligned regions of the page will have their buffer heads unmapped. Unblock aligned regions will be mapped if needed so that they can be updated with the partial zero out. This function is meant to be used to update a page and its buffer heads to be zeroed and unmapped when the corresponding blocks have been released or will be released. This routine is used in the following scenarios: * A hole is punched and the non page aligned regions of the head and tail of the hole need to be discarded * The file is truncated and the partial page beyond EOF needs to be discarded * The end of a hole is in the same page as EOF. After the page is flushed, the partial page beyond EOF needs to be discarded. * A write operation begins or ends inside a hole and the partial page appearing before or after the write needs to be discarded * A write operation extends EOF and the partial page beyond EOF needs to be discarded This function takes a flag EXT4_DISCARD_PARTIAL_PG_ZERO_UNMAPPED which is used when a write operation begins or ends in a hole. When the EXT4_DISCARD_PARTIAL_PG_ZERO_UNMAPPED flag is used, only buffer heads that are already unmapped will have the corresponding regions of the page zeroed. Signed-off-by: Allison Henderson <achender@linux.vnet.ibm.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> |
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| .. | ||
| acl.c | ||
| acl.h | ||
| balloc.c | ||
| bitmap.c | ||
| block_validity.c | ||
| dir.c | ||
| ext4_extents.h | ||
| ext4_jbd2.c | ||
| ext4_jbd2.h | ||
| ext4.h | ||
| extents.c | ||
| file.c | ||
| fsync.c | ||
| hash.c | ||
| ialloc.c | ||
| indirect.c | ||
| inode.c | ||
| ioctl.c | ||
| Kconfig | ||
| Makefile | ||
| mballoc.c | ||
| mballoc.h | ||
| migrate.c | ||
| mmp.c | ||
| move_extent.c | ||
| namei.c | ||
| page-io.c | ||
| resize.c | ||
| super.c | ||
| symlink.c | ||
| truncate.h | ||
| xattr_security.c | ||
| xattr_trusted.c | ||
| xattr_user.c | ||
| xattr.c | ||
| xattr.h | ||