diff options
Diffstat (limited to 'fs/xfs/xfs_aops.c')
| -rw-r--r-- | fs/xfs/xfs_aops.c | 15 |
1 files changed, 12 insertions, 3 deletions
diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c index 9f1420d41..b15db62b3 100644 --- a/fs/xfs/xfs_aops.c +++ b/fs/xfs/xfs_aops.c @@ -87,6 +87,12 @@ xfs_find_bdev_for_inode( * We're now finished for good with this page. Update the page state via the * associated buffer_heads, paying attention to the start and end offsets that * we need to process on the page. + * + * Landmine Warning: bh->b_end_io() will call end_page_writeback() on the last + * buffer in the IO. Once it does this, it is unsafe to access the bufferhead or + * the page at all, as we may be racing with memory reclaim and it can free both + * the bufferhead chain and the page as it will see the page as clean and + * unused. */ static void xfs_finish_page_writeback( @@ -95,8 +101,9 @@ xfs_finish_page_writeback( int error) { unsigned int end = bvec->bv_offset + bvec->bv_len - 1; - struct buffer_head *head, *bh; + struct buffer_head *head, *bh, *next; unsigned int off = 0; + unsigned int bsize; ASSERT(bvec->bv_offset < PAGE_SIZE); ASSERT((bvec->bv_offset & ((1 << inode->i_blkbits) - 1)) == 0); @@ -105,15 +112,17 @@ xfs_finish_page_writeback( bh = head = page_buffers(bvec->bv_page); + bsize = bh->b_size; do { + next = bh->b_this_page; if (off < bvec->bv_offset) goto next_bh; if (off > end) break; bh->b_end_io(bh, !error); next_bh: - off += bh->b_size; - } while ((bh = bh->b_this_page) != head); + off += bsize; + } while ((bh = next) != head); } /* |