diff options
author | Eric Sandeen <sandeen@redhat.com> | 2007-12-18 00:20:10 (GMT) |
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committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-12-18 03:28:17 (GMT) |
commit | 7a3f595cc8298df14a7c71b0d876bafd8e9e1cbf (patch) | |
tree | e2409b01431e230369182d3a450dcd9c2c6beb0a /fs/ecryptfs/mmap.c | |
parent | 8998979cc1f90da5a48b2e8a13833217c63f7c4a (diff) | |
download | linux-fsl-qoriq-7a3f595cc8298df14a7c71b0d876bafd8e9e1cbf.tar.xz |
ecryptfs: fix fsx data corruption problems
ecryptfs in 2.6.24-rc3 wasn't surviving fsx for me at all, dying after 4
ops. Generally, encountering problems with stale data and improperly
zeroed pages. An extending truncate + write for example would expose stale
data.
With the changes below I got to a million ops and beyond with all mmap ops
disabled - mmap still needs work. (A version of this patch on a RHEL5
kernel ran for over 110 million fsx ops)
I added a few comments as well, to the best of my understanding
as I read through the code.
Signed-off-by: Eric Sandeen <sandeen@redhat.com>
Acked-by: Michael Halcrow <mhalcrow@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/ecryptfs/mmap.c')
-rw-r--r-- | fs/ecryptfs/mmap.c | 31 |
1 files changed, 20 insertions, 11 deletions
diff --git a/fs/ecryptfs/mmap.c b/fs/ecryptfs/mmap.c index 16a7a55..32c5711 100644 --- a/fs/ecryptfs/mmap.c +++ b/fs/ecryptfs/mmap.c @@ -263,14 +263,13 @@ out: return 0; } +/* This function must zero any hole we create */ static int ecryptfs_prepare_write(struct file *file, struct page *page, unsigned from, unsigned to) { int rc = 0; + loff_t prev_page_end_size; - if (from == 0 && to == PAGE_CACHE_SIZE) - goto out; /* If we are writing a full page, it will be - up to date. */ if (!PageUptodate(page)) { rc = ecryptfs_read_lower_page_segment(page, page->index, 0, PAGE_CACHE_SIZE, @@ -283,22 +282,32 @@ static int ecryptfs_prepare_write(struct file *file, struct page *page, } else SetPageUptodate(page); } - if (page->index != 0) { - loff_t end_of_prev_pg_pos = - (((loff_t)page->index << PAGE_CACHE_SHIFT) - 1); - if (end_of_prev_pg_pos > i_size_read(page->mapping->host)) { + prev_page_end_size = ((loff_t)page->index << PAGE_CACHE_SHIFT); + + /* + * If creating a page or more of holes, zero them out via truncate. + * Note, this will increase i_size. + */ + if (page->index != 0) { + if (prev_page_end_size > i_size_read(page->mapping->host)) { rc = ecryptfs_truncate(file->f_path.dentry, - end_of_prev_pg_pos); + prev_page_end_size); if (rc) { printk(KERN_ERR "Error on attempt to " "truncate to (higher) offset [%lld];" - " rc = [%d]\n", end_of_prev_pg_pos, rc); + " rc = [%d]\n", prev_page_end_size, rc); goto out; } } - if (end_of_prev_pg_pos + 1 > i_size_read(page->mapping->host)) - zero_user_page(page, 0, PAGE_CACHE_SIZE, KM_USER0); + } + /* + * Writing to a new page, and creating a small hole from start of page? + * Zero it out. + */ + if ((i_size_read(page->mapping->host) == prev_page_end_size) && + (from != 0)) { + zero_user_page(page, 0, PAGE_CACHE_SIZE, KM_USER0); } out: return rc; |