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Subject[PATCH 26/26] NTFS 2.1.22 - Bug and race fixes and improved error handling.
Date
This is patch 26/26 in the series.  It contains the following ChangeSet:

<aia21@cantab.net> (04/11/10 1.2026.1.66)
NTFS: 2.1.22 - Many bug and race fixes and error handling improvements.

- Cleanup fs/ntfs/aops.c::ntfs_{read,write}page() since we know that a
resident attribute will be smaller than a page which makes the code
simpler. Also make the code more tolerant to concurrent ->truncate.

Signed-off-by: Anton Altaparmakov <aia21@cantab.net>

Best regards,

Anton
--
Anton Altaparmakov <aia21 at cam.ac.uk> (replace at with @)
Unix Support, Computing Service, University of Cambridge, CB2 3QH, UK
Linux NTFS maintainer / IRC: #ntfs on irc.freenode.net
WWW: http://linux-ntfs.sf.net/, http://www-stu.christs.cam.ac.uk/~aia21/

===================================================================

diff -Nru a/Documentation/filesystems/ntfs.txt b/Documentation/filesystems/ntfs.txt
--- a/Documentation/filesystems/ntfs.txt 2004-11-10 13:45:56 +00:00
+++ b/Documentation/filesystems/ntfs.txt 2004-11-10 13:45:56 +00:00
@@ -432,6 +432,9 @@

Note, a technical ChangeLog aimed at kernel hackers is in fs/ntfs/ChangeLog.

+2.1.22:
+ - Improve handling of ntfs volumes with errors.
+ - Fix various bugs and race conditions.
2.1.21:
- Fix several race conditions and various other bugs.
- Many internal cleanups, code reorganization, optimizations, and mft
diff -Nru a/fs/ntfs/ChangeLog b/fs/ntfs/ChangeLog
--- a/fs/ntfs/ChangeLog 2004-11-10 13:45:56 +00:00
+++ b/fs/ntfs/ChangeLog 2004-11-10 13:45:56 +00:00
@@ -25,7 +25,7 @@
- Enable the code for setting the NT4 compatibility flag when we start
making NTFS 1.2 specific modifications.

-2.1.22-WIP
+2.1.22 - Many bug and race fixes and error handling improvements.

- Improve error handling in fs/ntfs/inode.c::ntfs_truncate().
- Change fs/ntfs/inode.c::ntfs_truncate() to return an error code
@@ -85,6 +85,9 @@
complete runlist for the mft mirror is always mapped into memory.
- Add creation of buffers to fs/ntfs/mft.c::ntfs_sync_mft_mirror().
- Improve error handling in fs/ntfs/aops.c::ntfs_{read,write}_block().
+ - Cleanup fs/ntfs/aops.c::ntfs_{read,write}page() since we know that a
+ resident attribute will be smaller than a page which makes the code
+ simpler. Also make the code more tolerant to concurrent ->truncate.

2.1.21 - Fix some races and bugs, rewrite mft write code, add mft allocator.

diff -Nru a/fs/ntfs/Makefile b/fs/ntfs/Makefile
--- a/fs/ntfs/Makefile 2004-11-10 13:45:56 +00:00
+++ b/fs/ntfs/Makefile 2004-11-10 13:45:56 +00:00
@@ -6,7 +6,7 @@
index.o inode.o mft.o mst.o namei.o runlist.o super.o sysctl.o \
unistr.o upcase.o

-EXTRA_CFLAGS = -DNTFS_VERSION=\"2.1.22-WIP\"
+EXTRA_CFLAGS = -DNTFS_VERSION=\"2.1.22\"

ifeq ($(CONFIG_NTFS_DEBUG),y)
EXTRA_CFLAGS += -DDEBUG
diff -Nru a/fs/ntfs/aops.c b/fs/ntfs/aops.c
--- a/fs/ntfs/aops.c 2004-11-10 13:45:56 +00:00
+++ b/fs/ntfs/aops.c 2004-11-10 13:45:56 +00:00
@@ -341,7 +341,7 @@
*/
static int ntfs_readpage(struct file *file, struct page *page)
{
- s64 attr_pos;
+ loff_t i_size;
ntfs_inode *ni, *base_ni;
u8 *kaddr;
ntfs_attr_search_ctx *ctx;
@@ -350,7 +350,6 @@
int err = 0;

BUG_ON(!PageLocked(page));
-
/*
* This can potentially happen because we clear PageUptodate() during
* ntfs_writepage() of MstProtected() attributes.
@@ -359,7 +358,6 @@
unlock_page(page);
return 0;
}
-
ni = NTFS_I(page->mapping->host);

/* NInoNonResident() == NInoIndexAllocPresent() */
@@ -381,12 +379,23 @@
/* Normal data stream. */
return ntfs_read_block(page);
}
- /* Attribute is resident, implying it is not compressed or encrypted. */
+ /*
+ * Attribute is resident, implying it is not compressed or encrypted.
+ * This also means the attribute is smaller than an mft record and
+ * hence smaller than a page, so can simply zero out any pages with
+ * index above 0. We can also do this if the file size is 0.
+ */
+ if (unlikely(page->index > 0 || !i_size_read(VFS_I(ni)))) {
+ kaddr = kmap_atomic(page, KM_USER0);
+ memset(kaddr, 0, PAGE_CACHE_SIZE);
+ flush_dcache_page(page);
+ kunmap_atomic(kaddr, KM_USER0);
+ goto done;
+ }
if (!NInoAttr(ni))
base_ni = ni;
else
base_ni = ni->ext.base_ntfs_ino;
-
/* Map, pin, and lock the mft record. */
mrec = map_mft_record(base_ni);
if (IS_ERR(mrec)) {
@@ -402,35 +411,25 @@
CASE_SENSITIVE, 0, NULL, 0, ctx);
if (unlikely(err))
goto put_unm_err_out;
-
- /* Starting position of the page within the attribute value. */
- attr_pos = page->index << PAGE_CACHE_SHIFT;
-
- /* The total length of the attribute value. */
attr_len = le32_to_cpu(ctx->attr->data.resident.value_length);
-
+ i_size = i_size_read(VFS_I(ni));
+ if (unlikely(attr_len > i_size))
+ attr_len = i_size;
kaddr = kmap_atomic(page, KM_USER0);
- /* Copy over in bounds data, zeroing the remainder of the page. */
- if (attr_pos < attr_len) {
- u32 bytes = attr_len - attr_pos;
- if (bytes > PAGE_CACHE_SIZE)
- bytes = PAGE_CACHE_SIZE;
- else if (bytes < PAGE_CACHE_SIZE)
- memset(kaddr + bytes, 0, PAGE_CACHE_SIZE - bytes);
- /* Copy the data to the page. */
- memcpy(kaddr, attr_pos + (char*)ctx->attr +
- le16_to_cpu(
- ctx->attr->data.resident.value_offset), bytes);
- } else
- memset(kaddr, 0, PAGE_CACHE_SIZE);
+ /* Copy the data to the page. */
+ memcpy(kaddr, (u8*)ctx->attr +
+ le16_to_cpu(ctx->attr->data.resident.value_offset),
+ attr_len);
+ /* Zero the remainder of the page. */
+ memset(kaddr + attr_len, 0, PAGE_CACHE_SIZE - attr_len);
flush_dcache_page(page);
kunmap_atomic(kaddr, KM_USER0);
-
- SetPageUptodate(page);
put_unm_err_out:
ntfs_attr_put_search_ctx(ctx);
unm_err_out:
unmap_mft_record(base_ni);
+done:
+ SetPageUptodate(page);
err_out:
unlock_page(page);
return err;
@@ -1223,21 +1222,22 @@
*/
static int ntfs_writepage(struct page *page, struct writeback_control *wbc)
{
- s64 attr_pos;
+ loff_t i_size;
struct inode *vi;
ntfs_inode *ni, *base_ni;
char *kaddr;
ntfs_attr_search_ctx *ctx;
MFT_RECORD *m;
- u32 attr_len, bytes;
+ u32 attr_len;
int err;

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 >= (vi->i_size + PAGE_CACHE_SIZE - 1) >>
+ if (unlikely(page->index >= (i_size + PAGE_CACHE_SIZE - 1) >>
PAGE_CACHE_SHIFT)) {
/*
* The page may have dirty, unmapped buffers. Make them
@@ -1248,7 +1248,6 @@
ntfs_debug("Write outside i_size - truncated?");
return 0;
}
-
ni = NTFS_I(vi);

/* NInoNonResident() == NInoIndexAllocPresent() */
@@ -1284,9 +1283,9 @@
}
}
/* We have to zero every time due to mmap-at-end-of-file. */
- if (page->index >= (vi->i_size >> PAGE_CACHE_SHIFT)) {
+ if (page->index >= (i_size >> PAGE_CACHE_SHIFT)) {
/* The page straddles i_size. */
- unsigned int ofs = vi->i_size & ~PAGE_CACHE_MASK;
+ unsigned int ofs = i_size & ~PAGE_CACHE_MASK;
kaddr = kmap_atomic(page, KM_USER0);
memset(kaddr + ofs, 0, PAGE_CACHE_SIZE - ofs);
flush_dcache_page(page);
@@ -1300,16 +1299,25 @@
}
/*
* Attribute is resident, implying it is not compressed, encrypted,
- * sparse, or mst protected.
+ * sparse, or mst protected. This also means the attribute is smaller
+ * than an mft record and hence smaller than a page, so can simply
+ * return error on any pages with index above 0.
*/
BUG_ON(page_has_buffers(page));
BUG_ON(!PageUptodate(page));
-
+ if (unlikely(page->index > 0)) {
+ ntfs_error(vi->i_sb, "BUG()! page->index (0x%lx) > 0. "
+ "Aborting write.", page->index);
+ BUG_ON(PageWriteback(page));
+ set_page_writeback(page);
+ unlock_page(page);
+ end_page_writeback(page);
+ return -EIO;
+ }
if (!NInoAttr(ni))
base_ni = ni;
else
base_ni = ni->ext.base_ntfs_ino;
-
/* Map, pin, and lock the mft record. */
m = map_mft_record(base_ni);
if (IS_ERR(m)) {
@@ -1327,32 +1335,6 @@
CASE_SENSITIVE, 0, NULL, 0, ctx);
if (unlikely(err))
goto err_out;
-
- /* Starting position of the page within the attribute value. */
- attr_pos = page->index << PAGE_CACHE_SHIFT;
-
- /* The total length of the attribute value. */
- attr_len = le32_to_cpu(ctx->attr->data.resident.value_length);
-
- if (unlikely(vi->i_size != attr_len)) {
- ntfs_error(vi->i_sb, "BUG()! i_size (0x%llx) doesn't match "
- "attr_len (0x%x). Aborting write.", vi->i_size,
- attr_len);
- err = -EIO;
- goto err_out;
- }
- if (unlikely(attr_pos >= attr_len)) {
- ntfs_error(vi->i_sb, "BUG()! attr_pos (0x%llx) > attr_len "
- "(0x%x). Aborting write.",
- (unsigned long long)attr_pos, attr_len);
- err = -EIO;
- goto err_out;
- }
-
- bytes = attr_len - attr_pos;
- if (unlikely(bytes > PAGE_CACHE_SIZE))
- bytes = PAGE_CACHE_SIZE;
-
/*
* Keep the VM happy. This must be done otherwise the radix-tree tag
* PAGECACHE_TAG_DIRTY remains set even though the page is clean.
@@ -1384,26 +1366,30 @@
* TODO: ntfs_truncate(), others?
*/

+ attr_len = le32_to_cpu(ctx->attr->data.resident.value_length);
+ i_size = i_size_read(VFS_I(ni));
kaddr = kmap_atomic(page, KM_USER0);
+ if (unlikely(attr_len > i_size)) {
+ /* Zero out of bounds area in the mft record. */
+ memset((u8*)ctx->attr + le16_to_cpu(
+ ctx->attr->data.resident.value_offset) +
+ i_size, 0, attr_len - i_size);
+ attr_len = i_size;
+ }
/* Copy the data from the page to the mft record. */
- memcpy((u8*)ctx->attr + le16_to_cpu(
- ctx->attr->data.resident.value_offset) + attr_pos,
- kaddr, bytes);
+ memcpy((u8*)ctx->attr +
+ le16_to_cpu(ctx->attr->data.resident.value_offset),
+ kaddr, attr_len);
flush_dcache_mft_record_page(ctx->ntfs_ino);
-#if 0
- /* Zero out of bounds area. */
- if (likely(bytes < PAGE_CACHE_SIZE)) {
- memset(kaddr + bytes, 0, PAGE_CACHE_SIZE - bytes);
- flush_dcache_page(page);
- }
-#endif
+ /* Zero out of bounds area in the page cache page. */
+ memset(kaddr + attr_len, 0, PAGE_CACHE_SIZE - attr_len);
+ flush_dcache_page(page);
kunmap_atomic(kaddr, KM_USER0);

end_page_writeback(page);

/* Mark the mft record dirty, so it gets written back. */
mark_mft_record_dirty(ctx->ntfs_ino);
-
ntfs_attr_put_search_ctx(ctx);
unmap_mft_record(base_ni);
return 0;
@@ -1413,13 +1399,13 @@
"page so we try again later.");
/*
* Put the page back on mapping->dirty_pages, but leave its
- * buffer's dirty state as-is.
+ * buffers' dirty state as-is.
*/
redirty_page_for_writepage(wbc, page);
err = 0;
} else {
ntfs_error(vi->i_sb, "Resident attribute write failed with "
- "error %i. Setting page error flag.", -err);
+ "error %i. Setting page error flag.", err);
SetPageError(page);
}
unlock_page(page);
-
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