From ebab89909e0dc716282d5e7f6e73a3155fe66d4a Mon Sep 17 00:00:00 2001 From: Anton Altaparmakov Date: Sat, 3 Nov 2007 07:38:59 +0000 Subject: [PATCH] NTFS: Fix read regression. The regression was caused by: commit[a32ea1e1f925399e0d81ca3f7394a44a6dafa12c] Fix read/truncate race This causes ntfs_readpage() to be called for a zero i_size inode, which failed when the file was compressed and non-resident. Thanks a lot to Mike Galbraith for reporting the issue and tracking down the commit that caused the regression. Looking into it I found three bugs which the patch fixes. Signed-off-by: Anton Altaparmakov Tested-by: Mike Galbraith Signed-off-by: Linus Torvalds --- fs/ntfs/aops.c | 10 +++++++++- fs/ntfs/attrib.c | 5 +---- fs/ntfs/compress.c | 10 ++++++++++ 3 files changed, 20 insertions(+), 5 deletions(-) diff --git a/fs/ntfs/aops.c b/fs/ntfs/aops.c index cfdc7900d27..ad87cb01299 100644 --- a/fs/ntfs/aops.c +++ b/fs/ntfs/aops.c @@ -405,6 +405,15 @@ static int ntfs_readpage(struct file *file, struct page *page) retry_readpage: BUG_ON(!PageLocked(page)); + vi = page->mapping->host; + i_size = i_size_read(vi); + /* Is the page fully outside i_size? (truncate in progress) */ + if (unlikely(page->index >= (i_size + PAGE_CACHE_SIZE - 1) >> + PAGE_CACHE_SHIFT)) { + zero_user_page(page, 0, PAGE_CACHE_SIZE, KM_USER0); + ntfs_debug("Read outside i_size - truncated?"); + goto done; + } /* * This can potentially happen because we clear PageUptodate() during * ntfs_writepage() of MstProtected() attributes. @@ -413,7 +422,6 @@ retry_readpage: unlock_page(page); return 0; } - vi = page->mapping->host; ni = NTFS_I(vi); /* * Only $DATA attributes can be encrypted and only unnamed $DATA diff --git a/fs/ntfs/attrib.c b/fs/ntfs/attrib.c index 92dabdcf2b8..50d3b0c258e 100644 --- a/fs/ntfs/attrib.c +++ b/fs/ntfs/attrib.c @@ -179,10 +179,7 @@ int ntfs_map_runlist_nolock(ntfs_inode *ni, VCN vcn, ntfs_attr_search_ctx *ctx) * ntfs_mapping_pairs_decompress() fails. */ end_vcn = sle64_to_cpu(a->data.non_resident.highest_vcn) + 1; - if (!a->data.non_resident.lowest_vcn && end_vcn == 1) - end_vcn = sle64_to_cpu(a->data.non_resident.allocated_size) >> - ni->vol->cluster_size_bits; - if (unlikely(vcn >= end_vcn)) { + if (unlikely(vcn && vcn >= end_vcn)) { err = -ENOENT; goto err_out; } diff --git a/fs/ntfs/compress.c b/fs/ntfs/compress.c index d98daf59e0b..d1619d05eb2 100644 --- a/fs/ntfs/compress.c +++ b/fs/ntfs/compress.c @@ -561,6 +561,16 @@ int ntfs_read_compressed_block(struct page *page) read_unlock_irqrestore(&ni->size_lock, flags); max_page = ((i_size + PAGE_CACHE_SIZE - 1) >> PAGE_CACHE_SHIFT) - offset; + /* Is the page fully outside i_size? (truncate in progress) */ + if (xpage >= max_page) { + kfree(bhs); + kfree(pages); + zero_user_page(page, 0, PAGE_CACHE_SIZE, KM_USER0); + ntfs_debug("Compressed read outside i_size - truncated?"); + SetPageUptodate(page); + unlock_page(page); + return 0; + } if (nr_pages < max_page) max_page = nr_pages; for (i = 0; i < max_page; i++, offset++) {