diff options
| -rw-r--r-- | fs/xfs/linux-2.6/xfs_aops.c | 124 |
1 files changed, 114 insertions, 10 deletions
diff --git a/fs/xfs/linux-2.6/xfs_aops.c b/fs/xfs/linux-2.6/xfs_aops.c index 793908a8a09..9083357f9e4 100644 --- a/fs/xfs/linux-2.6/xfs_aops.c +++ b/fs/xfs/linux-2.6/xfs_aops.c @@ -39,6 +39,7 @@ #include "xfs_iomap.h" #include "xfs_vnodeops.h" #include "xfs_trace.h" +#include "xfs_bmap.h" #include <linux/mpage.h> #include <linux/pagevec.h> #include <linux/writeback.h> @@ -893,6 +894,118 @@ xfs_cluster_write( } } +STATIC void +xfs_vm_invalidatepage( + struct page *page, + unsigned long offset) +{ + trace_xfs_invalidatepage(page->mapping->host, page, offset); + block_invalidatepage(page, offset); +} + +/* + * If the page has delalloc buffers on it, we need to punch them out before we + * invalidate the page. If we don't, we leave a stale delalloc mapping on the + * inode that can trip a BUG() in xfs_get_blocks() later on if a direct IO read + * is done on that same region - the delalloc extent is returned when none is + * supposed to be there. + * + * We prevent this by truncating away the delalloc regions on the page before + * invalidating it. Because they are delalloc, we can do this without needing a + * transaction. Indeed - if we get ENOSPC errors, we have to be able to do this + * truncation without a transaction as there is no space left for block + * reservation (typically why we see a ENOSPC in writeback). + * + * This is not a performance critical path, so for now just do the punching a + * buffer head at a time. + */ +STATIC void +xfs_aops_discard_page( + struct page *page) +{ + struct inode *inode = page->mapping->host; + struct xfs_inode *ip = XFS_I(inode); + struct buffer_head *bh, *head; + loff_t offset = page_offset(page); + ssize_t len = 1 << inode->i_blkbits; + + if (!xfs_is_delayed_page(page, IOMAP_DELAY)) + goto out_invalidate; + + xfs_fs_cmn_err(CE_ALERT, ip->i_mount, + "page discard on page %p, inode 0x%llx, offset %llu.", + page, ip->i_ino, offset); + + xfs_ilock(ip, XFS_ILOCK_EXCL); + bh = head = page_buffers(page); + do { + int done; + xfs_fileoff_t offset_fsb; + xfs_bmbt_irec_t imap; + int nimaps = 1; + int error; + xfs_fsblock_t firstblock; + xfs_bmap_free_t flist; + + if (!buffer_delay(bh)) + goto next_buffer; + + offset_fsb = XFS_B_TO_FSBT(ip->i_mount, offset); + + /* + * Map the range first and check that it is a delalloc extent + * before trying to unmap the range. Otherwise we will be + * trying to remove a real extent (which requires a + * transaction) or a hole, which is probably a bad idea... + */ + error = xfs_bmapi(NULL, ip, offset_fsb, 1, + XFS_BMAPI_ENTIRE, NULL, 0, &imap, + &nimaps, NULL, NULL); + + if (error) { + /* something screwed, just bail */ + xfs_fs_cmn_err(CE_ALERT, ip->i_mount, + "page discard failed delalloc mapping lookup."); + break; + } + if (!nimaps) { + /* nothing there */ + goto next_buffer; + } + if (imap.br_startblock != DELAYSTARTBLOCK) { + /* been converted, ignore */ + goto next_buffer; + } + WARN_ON(imap.br_blockcount == 0); + + /* + * Note: while we initialise the firstblock/flist pair, they + * should never be used because blocks should never be + * allocated or freed for a delalloc extent and hence we need + * don't cancel or finish them after the xfs_bunmapi() call. + */ + xfs_bmap_init(&flist, &firstblock); + error = xfs_bunmapi(NULL, ip, offset_fsb, 1, 0, 1, &firstblock, + &flist, NULL, &done); + + ASSERT(!flist.xbf_count && !flist.xbf_first); + if (error) { + /* something screwed, just bail */ + xfs_fs_cmn_err(CE_ALERT, ip->i_mount, + "page discard unable to remove delalloc mapping."); + break; + } +next_buffer: + offset += len; + + } while ((bh = bh->b_this_page) != head); + + xfs_iunlock(ip, XFS_ILOCK_EXCL); +out_invalidate: + xfs_vm_invalidatepage(page, 0); + return; +} + /* * Calling this without startio set means we are being asked to make a dirty * page ready for freeing it's buffers. When called with startio set then @@ -1144,7 +1257,7 @@ error: */ if (err != -EAGAIN) { if (!unmapped) - block_invalidatepage(page, 0); + xfs_aops_discard_page(page); ClearPageUptodate(page); } return err; @@ -1554,15 +1667,6 @@ xfs_vm_readpages( return mpage_readpages(mapping, pages, nr_pages, xfs_get_blocks); } -STATIC void -xfs_vm_invalidatepage( - struct page *page, - unsigned long offset) -{ - trace_xfs_invalidatepage(page->mapping->host, page, offset); - block_invalidatepage(page, offset); -} - const struct address_space_operations xfs_address_space_operations = { .readpage = xfs_vm_readpage, .readpages = xfs_vm_readpages, |