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authorLukas Czerner <lczerner@redhat.com>2013-05-21 23:17:23 -0400
committerTheodore Ts'o <tytso@mit.edu>2013-05-21 23:17:23 -0400
commitd47992f86b307985b3215bcf141d56d1849d71df (patch)
treee1ae47bd19185371462c5a273c15276534447349 /Documentation/filesystems/Locking
parentc7788792a5e7b0d5d7f96d0766b4cb6112d47d75 (diff)
downloadblackbird-obmc-linux-d47992f86b307985b3215bcf141d56d1849d71df.tar.gz
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mm: change invalidatepage prototype to accept length
Currently there is no way to truncate partial page where the end truncate point is not at the end of the page. This is because it was not needed and the functionality was enough for file system truncate operation to work properly. However more file systems now support punch hole feature and it can benefit from mm supporting truncating page just up to the certain point. Specifically, with this functionality truncate_inode_pages_range() can be changed so it supports truncating partial page at the end of the range (currently it will BUG_ON() if 'end' is not at the end of the page). This commit changes the invalidatepage() address space operation prototype to accept range to be invalidated and update all the instances for it. We also change the block_invalidatepage() in the same way and actually make a use of the new length argument implementing range invalidation. Actual file system implementations will follow except the file systems where the changes are really simple and should not change the behaviour in any way .Implementation for truncate_page_range() which will be able to accept page unaligned ranges will follow as well. Signed-off-by: Lukas Czerner <lczerner@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Hugh Dickins <hughd@google.com>
Diffstat (limited to 'Documentation/filesystems/Locking')
-rw-r--r--Documentation/filesystems/Locking6
1 files changed, 3 insertions, 3 deletions
diff --git a/Documentation/filesystems/Locking b/Documentation/filesystems/Locking
index 0706d32a61e6..cbbac3fa0eb4 100644
--- a/Documentation/filesystems/Locking
+++ b/Documentation/filesystems/Locking
@@ -189,7 +189,7 @@ prototypes:
loff_t pos, unsigned len, unsigned copied,
struct page *page, void *fsdata);
sector_t (*bmap)(struct address_space *, sector_t);
- int (*invalidatepage) (struct page *, unsigned long);
+ void (*invalidatepage) (struct page *, unsigned int, unsigned int);
int (*releasepage) (struct page *, int);
void (*freepage)(struct page *);
int (*direct_IO)(int, struct kiocb *, const struct iovec *iov,
@@ -310,8 +310,8 @@ filesystems and by the swapper. The latter will eventually go away. Please,
keep it that way and don't breed new callers.
->invalidatepage() is called when the filesystem must attempt to drop
-some or all of the buffers from the page when it is being truncated. It
-returns zero on success. If ->invalidatepage is zero, the kernel uses
+some or all of the buffers from the page when it is being truncated. It
+returns zero on success. If ->invalidatepage is zero, the kernel uses
block_invalidatepage() instead.
->releasepage() is called when the kernel is about to try to drop the
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