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Commit e9042fae authored by Anton Altaparmakov's avatar Anton Altaparmakov
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NTFS: Initial implementation of write(2) based overwriting of existing 

files on ntfs. (Note: Resident files are not supported yet, so avoid
writing to files smaller than 1kiB.)
parent 1a683e2e
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Showing with 847 additions and 22 deletions
Documentation/filesystems/ntfs.txt
View file @ e9042fae
......@@ -247,6 +247,11 @@ ChangeLog
Note, a technical ChangeLog aimed at kernel hackers is in fs/ntfs/ChangeLog.
2.1.0:
- Add configuration option for developmental write support.
- Initial implementation of file overwriting. (Writes to resident files
are not written out to disk yet, so avoid writing to files smaller
than about 1kiB.)
2.0.25:
- Minor bugfixes in error code paths and small cleanups.
2.0.24:
......
fs/ntfs/ChangeLog
View file @ e9042fae
ToDo:
- Find and fix bugs.
- Enable NFS exporting of NTFS.
- Implement aops->set_page_dirty() in order to take control of buffer
dirtying. Not having it means if page_has_buffers(), all buffers
will be dirtied with the page. And if not they won't be. That is
fine for the moment but will break once we enable metadata updates.
- Implement sops->dirty_inode() to implement {a,m,c} time updates and
such things.
- Implement sops->write_inode().
- In between ntfs_prepare/commit_write, need exclusion between
simultaneous file extensions. Need perhaps an NInoResizeUnderway()
flag which we can set in ntfs_prepare_write() and clear again in
ntfs_commit_write(). Just have to be careful in readpage/writepage,
as well as in truncate, that we play nice... We might need to have
a data_size field in the ntfs_inode to store the real attribute
length. Also need to be careful with initialized_size extention in
ntfs_prepare_write. Basically, just be _very_ careful in this code...
OTOH, perhaps i_sem, which is held accross generic_file_write is
sufficient for synchronisation here. We then just need to make sure
ntfs_readpage/writepage/truncate interoperate properly with us.
2.1.0 - First steps towards write support: implement file overwrite.
- Add configuration option for developmental write support with an
appropriately scary configuration help text.
- Initial implementation of fs/ntfs/aops.c::ntfs_writepage() and its
helper fs/ntfs/aops.c::ntfs_write_block(). This enables mmap(2) based
overwriting of existing files on ntfs. Note: Resident files are
only written into memory, and not written out to disk at present, so
avoid writing to files smaller than about 1kiB.
- Initial implementation of fs/ntfs/aops.c::ntfs_prepare_write(), its
helper fs/ntfs/aops.c::ntfs_prepare_nonresident_write() and their
counterparts, fs/ntfs/aops.c::ntfs_commit_write(), and
fs/ntfs/aops.c::ntfs_commit_nonresident_write(), respectively. Also,
add generic_file_write() to the ntfs file operations (fs/ntfs/file.c).
This enables write(2) based overwriting of existing files on ntfs.
Note: As with mmap(2) based overwriting, resident files are only
written into memory, and not written out to disk at present, so avoid
writing to files smaller than about 1kiB.
2.0.25 - Small bug fixes and cleanups.
......
fs/ntfs/aops.c
View file @ e9042fae
......@@ -462,12 +462,12 @@ static int ntfs_write_block(struct page *page)
{
VCN vcn;
LCN lcn;
sector_t block, dblock, iblock;
struct inode *vi;
ntfs_inode *ni;
ntfs_volume *vol;
run_list_element *rl;
struct buffer_head *bh, *head;
sector_t block, dblock, iblock;
unsigned int blocksize, vcn_ofs;
int err;
BOOL need_end_writeback;
......@@ -586,9 +586,12 @@ static int ntfs_write_block(struct page *page)
}
/*
* The current page straddles initialized size. Zero
* all non-uptodate buffers and set them uptodate.
* Note, there aren't any non-uptodate buffers if the
* page is uptodate.
* all non-uptodate buffers and set them uptodate (and
* dirty?). Note, there aren't any non-uptodate buffers
* if the page is uptodate.
* FIXME: For an uptodate page, the buffers may need to
* be written out because they were not initialized on
* disk before.
*/
if (!PageUptodate(page)) {
// TODO:
......@@ -605,6 +608,10 @@ static int ntfs_write_block(struct page *page)
"is not supported yet. Sorry.");
err = -EOPNOTSUPP;
break;
// Do NOT set_buffer_new() BUT DO clear buffer range
// outside write request range.
// set_buffer_uptodate() on complete buffers as well as
// set_buffer_dirty().
}
/* No need to map buffers that are already mapped. */
......@@ -785,12 +792,11 @@ static int ntfs_write_block(struct page *page)
*
* Return 0 on success and -errno on error.
*/
int ntfs_writepage(struct page *page)
static int ntfs_writepage(struct page *page)
{
s64 attr_pos;
struct inode *vi;
ntfs_inode *ni, *base_ni;
ntfs_volume *vol;
char *kaddr;
attr_search_context *ctx;
MFT_RECORD *m;
......@@ -810,7 +816,6 @@ int ntfs_writepage(struct page *page)
}
ni = NTFS_I(vi);
vol = ni->vol;
if (NInoNonResident(ni)) {
/*
......@@ -830,7 +835,7 @@ int ntfs_writepage(struct page *page)
// TODO: Implement and replace this check with
// return ntfs_write_compressed_block(page);
unlock_page(page);
ntfs_error(vol->sb, "Writing to compressed "
ntfs_error(vi->i_sb, "Writing to compressed "
"files is not supported yet. "
"Sorry.");
return -EOPNOTSUPP;
......@@ -838,7 +843,7 @@ int ntfs_writepage(struct page *page)
// TODO: Implement and remove this check.
if (NInoSparse(ni)) {
unlock_page(page);
ntfs_error(vol->sb, "Writing to sparse files "
ntfs_error(vi->i_sb, "Writing to sparse files "
"is not supported yet. Sorry.");
return -EOPNOTSUPP;
}
......@@ -857,7 +862,7 @@ int ntfs_writepage(struct page *page)
// TODO: Implement and remove this check.
if (NInoMstProtected(ni)) {
unlock_page(page);
ntfs_error(vol->sb, "Writing to MST protected "
ntfs_error(vi->i_sb, "Writing to MST protected "
"attributes is not supported yet. "
"Sorry.");
return -EOPNOTSUPP;
......@@ -889,7 +894,7 @@ int ntfs_writepage(struct page *page)
else
base_ni = ni->_INE(base_ntfs_ino);
/* Map, pin and lock the mft record. */
/* Map, pin, and lock the mft record. */
m = map_mft_record(base_ni);
if (unlikely(IS_ERR(m))) {
err = PTR_ERR(m);
......@@ -915,14 +920,14 @@ int ntfs_writepage(struct page *page)
attr_len = le32_to_cpu(ctx->attr->_ARA(value_length));
if (unlikely(vi->i_size != attr_len)) {
ntfs_error(vol->sb, "BUG()! i_size (0x%Lx) doesn't match "
ntfs_error(vi->i_sb, "BUG()! i_size (0x%Lx) 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(vol->sb, "BUG()! attr_pos (0x%Lx) > attr_len (0x%x)"
ntfs_error(vi->i_sb, "BUG()! attr_pos (0x%Lx) > attr_len (0x%x)"
". Aborting write.", attr_pos, attr_len);
err = -EIO;
goto err_out;
......@@ -953,6 +958,7 @@ int ntfs_writepage(struct page *page)
/* Copy the data from the page to the mft record. */
memcpy((u8*)ctx->attr + le16_to_cpu(ctx->attr->_ARA(value_offset)) +
attr_pos, kaddr, bytes);
flush_dcache_mft_record_page(ctx->ntfs_ino);
#if 0
/* Zero out of bounds area. */
if (likely(bytes < PAGE_CACHE_SIZE)) {
......@@ -965,7 +971,7 @@ int ntfs_writepage(struct page *page)
unlock_page(page);
// TODO: Mark mft record dirty so it gets written back.
ntfs_error(vol->sb, "Writing to resident files is not supported yet. "
ntfs_error(vi->i_sb, "Writing to resident files is not supported yet. "
"Wrote to memory only...");
put_attr_search_ctx(ctx);
......@@ -973,7 +979,7 @@ int ntfs_writepage(struct page *page)
return 0;
err_out:
if (err == -ENOMEM) {
ntfs_warning(vol->sb, "Error allocating memory. Redirtying "
ntfs_warning(vi->i_sb, "Error allocating memory. Redirtying "
"page so we try again later.");
/*
* Put the page back on mapping->dirty_pages, but leave its
......@@ -985,7 +991,7 @@ int ntfs_writepage(struct page *page)
__set_page_dirty_nobuffers(page);
err = 0;
} else {
ntfs_error(vol->sb, "Resident attribute write failed with "
ntfs_error(vi->i_sb, "Resident attribute write failed with "
"error %i. Setting page error flag.", -err);
SetPageError(page);
}
......@@ -997,6 +1003,765 @@ int ntfs_writepage(struct page *page)
return err;
}
/**
* ntfs_prepare_nonresident_write -
*
*/
static int ntfs_prepare_nonresident_write(struct page *page,
unsigned from, unsigned to)
{
VCN vcn;
LCN lcn;
sector_t block, ablock, iblock;
struct inode *vi;
ntfs_inode *ni;
ntfs_volume *vol;
run_list_element *rl;
struct buffer_head *bh, *head, *wait[2], **wait_bh = wait;
char *kaddr = page_address(page);
unsigned int vcn_ofs, block_start, block_end, blocksize;
int err;
BOOL is_retry;
unsigned char blocksize_bits;
vi = page->mapping->host;
ni = NTFS_I(vi);
vol = ni->vol;
ntfs_debug("Entering for inode %li, attribute type 0x%x, page index "
"0x%lx, from = %u, to = %u.", vi->i_ino, ni->type,
page->index, from, to);
BUG_ON(!NInoNonResident(ni));
BUG_ON(NInoMstProtected(ni));
blocksize_bits = vi->i_blkbits;
blocksize = 1 << blocksize_bits;
/*
* create_empty_buffers() will create uptodate/dirty buffers if the
* page is uptodate/dirty.
*/
if (!page_has_buffers(page))
create_empty_buffers(page, blocksize, 0);
bh = head = page_buffers(page);
if (unlikely(!bh))
return -ENOMEM;
/* The first block in the page. */
block = page->index << (PAGE_CACHE_SHIFT - blocksize_bits);
/*
* The first out of bounds block for the allocated size. No need to
* round up as allocated_size is in multiples of cluster size and the
* minimum cluster size is 512 bytes, which is equal to the smallest
* blocksize.
*/
ablock = ni->allocated_size >> blocksize_bits;
/* The last (fully or partially) initialized block. */
iblock = ni->initialized_size >> blocksize_bits;
/* Loop through all the buffers in the page. */
block_start = 0;
rl = NULL;
err = 0;
do {
block_end = block_start + blocksize;
/*
* If buffer @bh is outside the write, just mark it uptodate
* if the page is uptodate and continue with the next buffer.
*/
if (block_end <= from || block_start >= to) {
if (PageUptodate(page)) {
if (!buffer_uptodate(bh))
set_buffer_uptodate(bh);
}
continue;
}
/*
* @bh is at least partially being written to.
* Make sure it is not marked as new.
*/
//if (buffer_new(bh))
// clear_buffer_new(bh);
if (block >= ablock) {
// TODO: block is above allocated_size, need to
// allocate it. Best done in one go to accomodate not
// only block but all above blocks up to and including:
// ((page->index << PAGE_CACHE_SHIFT) + to + blocksize
// - 1) >> blobksize_bits. Obviously will need to round
// up to next cluster boundary, too. This should be
// done with a helper function, so it can be reused.
ntfs_error(vol->sb, "Writing beyond allocated size "
"is not supported yet. Sorry.");
err = -EOPNOTSUPP;
goto err_out;
// Need to update ablock.
// Need to set_buffer_new() on all block bhs that are
// newly allocated.
}
/*
* Now we have enough allocated size to fulfill the whole
* request, i.e. block < ablock is true.
*/
if (unlikely((block >= iblock) &&
(ni->initialized_size < vi->i_size))) {
/*
* If this page is fully outside initialized size, zero
* out all pages between the current initialized size
* and the current page. Just use ntfs_readpage() to do
* the zeroing transparently.
*/
if (block > iblock) {
// TODO:
// For each page do:
// - read_cache_page()
// Again for each page do:
// - wait_on_page_locked()
// - Check (PageUptodate(page) &&
// !PageError(page))
// Update initialized size in the attribute and
// in the inode.
// Again, for each page do:
// __set_page_dirty_buffers();
// page_cache_release()
// We don't need to wait on the writes.
// Update iblock.
}
/*
* The current page straddles initialized size. Zero
* all non-uptodate buffers and set them uptodate (and
* dirty?). Note, there aren't any non-uptodate buffers
* if the page is uptodate.
* FIXME: For an uptodate page, the buffers may need to
* be written out because they were not initialized on
* disk before.
*/
if (!PageUptodate(page)) {
// TODO:
// Zero any non-uptodate buffers up to i_size.
// Set them uptodate and dirty.
}
// TODO:
// Update initialized size in the attribute and in the
// inode (up to i_size).
// Update iblock.
// FIXME: This is inefficient. Try to batch the two
// size changes to happen in one go.
ntfs_error(vol->sb, "Writing beyond initialized size "
"is not supported yet. Sorry.");
err = -EOPNOTSUPP;
goto err_out;
// Do NOT set_buffer_new() BUT DO clear buffer range
// outside write request range.
// set_buffer_uptodate() on complete buffers as well as
// set_buffer_dirty().
}
/* Need to map unmapped buffers. */
if (!buffer_mapped(bh)) {
/* Unmapped buffer. Need to map it. */
bh->b_bdev = vol->sb->s_bdev;
/* Convert block into corresponding vcn and offset. */
vcn = (VCN)block << blocksize_bits >>
vol->cluster_size_bits;
vcn_ofs = ((VCN)block << blocksize_bits) &
vol->cluster_size_mask;
is_retry = FALSE;
if (!rl) {
lock_retry_remap:
down_read(&ni->run_list.lock);
rl = ni->run_list.rl;
}
if (likely(rl != NULL)) {
/* Seek to element containing target vcn. */
while (rl->length && rl[1].vcn <= vcn)
rl++;
lcn = vcn_to_lcn(rl, vcn);
} else
lcn = (LCN)LCN_RL_NOT_MAPPED;
if (unlikely(lcn < 0)) {
/*
* We extended the attribute allocation above.
* If we hit an ENOENT here it means that the
* allocation was insufficient which is a bug.
*/
BUG_ON(lcn == LCN_ENOENT);
/* It is a hole, need to instantiate it. */
if (lcn == LCN_HOLE) {
// TODO: Instantiate the hole.
// clear_buffer_new(bh);
// unmap_underlying_metadata(bh->b_bdev,
// bh->b_blocknr);
// For non-uptodate buffers, need to
// zero out the region outside the
// request in this bh or all bhs,
// depending on what we implemented
// above.
// Need to flush_dcache_page().
// Or could use set_buffer_new()
// instead?
ntfs_error(vol->sb, "Writing into "
"sparse regions is "
"not supported yet. "
"Sorry.");
err = -EOPNOTSUPP;
goto err_out;
} else if (!is_retry &&
lcn == LCN_RL_NOT_MAPPED) {
is_retry = TRUE;
/*
* Attempt to map run list, dropping
* lock for the duration.
*/
up_read(&ni->run_list.lock);
err = map_run_list(ni, vcn);
if (likely(!err))
goto lock_retry_remap;
rl = NULL;
}
/*
* Failed to map the buffer, even after
* retrying.
*/
bh->b_blocknr = -1UL;
ntfs_error(vol->sb, "vcn_to_lcn(vcn = 0x%Lx) "
"failed with error code "
"0x%Lx%s.", (long long)vcn,
(long long)-lcn, is_retry ?
" even after retrying" : "");
// FIXME: Depending on vol->on_errors, do
// something.
if (!err)
err = -EIO;
goto err_out;
}
/* We now have a successful remap, i.e. lcn >= 0. */
/* Setup buffer head to correct block. */
bh->b_blocknr = ((lcn << vol->cluster_size_bits)
+ vcn_ofs) >> blocksize_bits;
set_buffer_mapped(bh);
// FIXME: Something analogous to this is needed for
// each newly allocated block, i.e. BH_New.
// FIXME: Might need to take this out of the
// if (!buffer_mapped(bh)) {}, depending on how we
// implement things during the allocated_size and
// initialized_size extension code above.
if (buffer_new(bh)) {
clear_buffer_new(bh);
unmap_underlying_metadata(bh->b_bdev,
bh->b_blocknr);
if (PageUptodate(page)) {
set_buffer_uptodate(bh);
continue;
}
/*
* Page is _not_ uptodate, zero surrounding
* region. NOTE: This is how we decide if to
* zero or not!
*/
if (block_end > to)
memset(kaddr + to, 0, block_end - to);
if (block_start < from)
memset(kaddr + block_start, 0,
from - block_start);
if (block_end > to || block_start < from)
flush_dcache_page(page);
continue;
}
}
/* @bh is mapped, set it uptodate if the page is uptodate. */
if (PageUptodate(page)) {
if (!buffer_uptodate(bh))
set_buffer_uptodate(bh);
continue;
}
/*
* The page is not uptodate. The buffer is mapped. If it is not
* uptodate, and it is only partially being written to, we need
* to read the buffer in before the write, i.e. right now.
*/
if (!buffer_uptodate(bh) &&
(block_start < from || block_end > to)) {
ll_rw_block(READ, 1, &bh);
*wait_bh++ = bh;
}
} while (block++, block_start = block_end,
(bh = bh->b_this_page) != head);
/* Release the lock if we took it. */
if (rl) {
up_read(&ni->run_list.lock);
rl = NULL;
}
/* If we issued read requests, let them complete. */
while (wait_bh > wait) {
wait_on_buffer(*--wait_bh);
if (!buffer_uptodate(*wait_bh))
return -EIO;
}
ntfs_debug("Done.");
return 0;
err_out:
/*
* Zero out any newly allocated blocks to avoid exposing stale data.
* If BH_New is set, we know that the block was newly allocated in the
* above loop.
* FIXME: What about initialized_size increments? Have we done all the
* required zeroing above? If not this error handling is broken, and
* in particular the if (block_end <= from) check is completely bogus.
*/
bh = head;
block_start = 0;
is_retry = FALSE;
do {
block_end = block_start + blocksize;
if (block_end <= from)
continue;
if (block_start >= to)
break;
if (buffer_new(bh)) {
clear_buffer_new(bh);
if (buffer_uptodate(bh))
buffer_error();
memset(kaddr + block_start, 0, bh->b_size);
set_buffer_uptodate(bh);
mark_buffer_dirty(bh);
is_retry = TRUE;
}
} while (block_start = block_end, (bh = bh->b_this_page) != head);
if (is_retry)
flush_dcache_page(page);
if (rl)
up_read(&ni->run_list.lock);
return err;
}
/**
* ntfs_prepare_write - prepare a page for receiving data
*
* This is called from generic_file_write() with i_sem held on the inode
* (@page->mapping->host). The @page is locked and kmap()ped so page_address()
* can simply be used. The source data has not yet been copied into the @page.
*
* Need to extend the attribute/fill in holes if necessary, create blocks and
* make partially overwritten blocks uptodate,
*
* i_size is not to be modified yet.
*
* Return 0 on success or -errno on error.
*
* Should be using block_prepare_write() [support for sparse files] or
* cont_prepare_write() [no support for sparse files]. Can't do that due to
* ntfs specifics but can look at them for implementation guidancea.
*
* Note: In the range, @from is inclusive and @to is exclusive, i.e. @from is
* the first byte in the page that will be written to and @to is the first byte
* after the last byte that will be written to.
*/
static int ntfs_prepare_write(struct file *file, struct page *page,
unsigned from, unsigned to)
{
struct inode *vi = page->mapping->host;
ntfs_inode *ni = NTFS_I(vi);
ntfs_debug("Entering for inode %li, attribute type 0x%x, page index "
"0x%lx, from = %u, to = %u.", vi->i_ino, ni->type,
page->index, from, to);
BUG_ON(!PageLocked(page));
BUG_ON(from > PAGE_CACHE_SIZE);
BUG_ON(to > PAGE_CACHE_SIZE);
BUG_ON(from > to);
if (NInoNonResident(ni)) {
/*
* Only unnamed $DATA attributes can be compressed, encrypted,
* and/or sparse.
*/
if (ni->type == AT_DATA && !ni->name_len) {
/* If file is encrypted, deny access, just like NT4. */
if (NInoEncrypted(ni)) {
ntfs_debug("Denying write access to encrypted "
"file.");
return -EACCES;
}
/* Compressed data streams are handled in compress.c. */
if (NInoCompressed(ni)) {
// TODO: Implement and replace this check with
// return ntfs_write_compressed_block(page);
ntfs_error(vi->i_sb, "Writing to compressed "
"files is not supported yet. "
"Sorry.");
return -EOPNOTSUPP;
}
// TODO: Implement and remove this check.
if (NInoSparse(ni)) {
ntfs_error(vi->i_sb, "Writing to sparse files "
"is not supported yet. Sorry.");
return -EOPNOTSUPP;
}
}
// TODO: Implement and remove this check.
if (NInoMstProtected(ni)) {
ntfs_error(vi->i_sb, "Writing to MST protected "
"attributes is not supported yet. "
"Sorry.");
return -EOPNOTSUPP;
}
/* Normal data stream. */
return ntfs_prepare_nonresident_write(page, from, to);
}
/*
* Attribute is resident, implying it is not compressed, encrypted, or
* mst protected.
*/
BUG_ON(page_has_buffers(page));
/* Do we need to resize the attribute? */
if (((s64)page->index << PAGE_CACHE_SHIFT) + to > vi->i_size) {
// TODO: Implement resize...
ntfs_error(vi->i_sb, "Writing beyond the existing file size is "
"not supported yet. Sorry.");
return -EOPNOTSUPP;
}
/*
* Because resident attributes are handled by memcpy() to/from the
* corresponding MFT record, and because this form of i/o is byte
* aligned rather than block aligned, there is no need to bring the
* page uptodate here as in the non-resident case where we need to
* bring the buffers straddled by the write uptodate before
* generic_file_write() does the copying from userspace.
*
* We thus defer the uptodate bringing of the page region outside the
* region written to to ntfs_commit_write(). The reason for doing this
* is that we save one round of:
* map_mft_record(), get_attr_search_ctx(), lookup_attr(),
* kmap_atomic(), kunmap_atomic(), put_attr_search_ctx(),
* unmap_mft_record().
* Which is obviously a very worthwhile save.
*
* Thus we just return success now...
*/
ntfs_debug("Done.");
return 0;
}
/*
* NOTES: There is a disparity between the apparent need to extend the
* attribute in prepare write but to update i_size only in commit write.
* Need to make sure i_sem protection is sufficient. And if not will need to
* handle this in some way or another.
*/
/**
* ntfs_commit_nonresident_write -
*
*/
static int ntfs_commit_nonresident_write(struct page *page,
unsigned from, unsigned to)
{
s64 pos = ((s64)page->index << PAGE_CACHE_SHIFT) + to;
struct inode *vi;
struct buffer_head *bh, *head;
unsigned int block_start, block_end, blocksize;
BOOL partial;
vi = page->mapping->host;
ntfs_debug("Entering for inode %li, attribute type 0x%x, page index "
"0x%lx, from = %u, to = %u.", vi->i_ino,
NTFS_I(vi)->type, page->index, from, to);
blocksize = 1 << vi->i_blkbits;
// FIXME: We need a whole slew of special cases in here for MST
// protected attributes for example. For compressed files, too...
// For now, we know ntfs_prepare_write() would have failed so we can't
// get here in any of the cases which we have to special case, so we
// are just a ripped off unrolled generic_commit_write() at present.
bh = head = page_buffers(page);
block_start = 0;
partial = FALSE;
do {
block_end = block_start + blocksize;
if (block_end <= from || block_start >= to) {
if (!buffer_uptodate(bh))
partial = TRUE;
} else {
set_buffer_uptodate(bh);
mark_buffer_dirty(bh);
}
} while (block_start = block_end, (bh = bh->b_this_page) != head);
/*
* If this is a partial write which happened to make all buffers
* uptodate then we can optimize away a bogus ->readpage() for the next
* read(). Here we 'discover' whether the page went uptodate as a
* result of this (potentially partial) write.
*/
if (!partial)
SetPageUptodate(page);
/*
* Not convinced about this at all. See disparity comment above. For
* now we know ntfs_prepare_write() would have failed in the write
* exceeds i_size case, so this will never trigger which is fine.
*/
if (pos > vi->i_size) {
vi->i_size = pos;
mark_inode_dirty(vi);
}
ntfs_debug("Done.");
return 0;
}
/**
* ntfs_commit_write - commit the received data
*
* This is called from generic_file_write() with i_sem held on the inode
* (@page->mapping->host). The @page is locked and kmap()ped so page_address()
* can simply be used. The source data has already been copied into the @page.
*
* Need to mark modified blocks dirty so they get written out later when
* ntfs_writepage() is invoked by the VM.
*
* Return 0 on success or -errno on error.
*
* Should be using generic_commit_write(). This marks buffers uptodate and
* dirty, sets the page uptodate if all buffers in the page are uptodate, and
* updates i_size if the end of io is beyond i_size. In that case, it also
* marks the inode dirty. - We could still use this (obviously except for
* NInoMstProtected() attributes, where we will need to duplicate the core code
* because we need our own async_io completion handler) but we could just do
* the i_size update in prepare write, when we resize the attribute. Then
* we would avoid the i_size update and mark_inode_dirty() happening here.
*
* Can't use generic_commit_write() due to ntfs specialities but can look at
* it for implementation guidance.
*
* If things have gone as outlined in ntfs_prepare_write(), then we do not
* need to do any page content modifications here at all, except in the write
* to resident attribute case, where we need to do the uptodate bringing here
* which we combine with the copying into the mft record which means we only
* need to map the mft record and find the attribute record in it only once.
*/
static int ntfs_commit_write(struct file *file, struct page *page,
unsigned from, unsigned to)
{
s64 attr_pos;
struct inode *vi;
ntfs_inode *ni, *base_ni;
char *kaddr, *kattr;
attr_search_context *ctx;
MFT_RECORD *m;
u32 attr_len, bytes;
int err;
vi = page->mapping->host;
ni = NTFS_I(vi);
ntfs_debug("Entering for inode %li, attribute type 0x%x, page index "
"0x%lx, from = %u, to = %u.", vi->i_ino, ni->type,
page->index, from, to);
if (NInoNonResident(ni)) {
/*
* Only unnamed $DATA attributes can be compressed, encrypted,
* and/or sparse.
*/
if (ni->type == AT_DATA && !ni->name_len) {
/* If file is encrypted, deny access, just like NT4. */
if (NInoEncrypted(ni)) {
// Should never get here!
ntfs_debug("Denying write access to encrypted "
"file.");
return -EACCES;
}
/* Compressed data streams are handled in compress.c. */
if (NInoCompressed(ni)) {
// TODO: Implement and replace this check with
// return ntfs_write_compressed_block(page);
// Should never get here!
ntfs_error(vi->i_sb, "Writing to compressed "
"files is not supported yet. "
"Sorry.");
return -EOPNOTSUPP;
}
// TODO: Implement and remove this check.
if (NInoSparse(ni)) {
// Should never get here!
ntfs_error(vi->i_sb, "Writing to sparse files "
"is not supported yet. Sorry.");
return -EOPNOTSUPP;
}
}
// TODO: Implement and remove this check.
if (NInoMstProtected(ni)) {
// Should never get here!
ntfs_error(vi->i_sb, "Writing to MST protected "
"attributes is not supported yet. "
"Sorry.");
return -EOPNOTSUPP;
}
/* Normal data stream. */
return ntfs_commit_nonresident_write(page, from, to);
}
/*
* Attribute is resident, implying it is not compressed, encrypted, or
* mst protected.
*/
/* Do we need to resize the attribute? */
if (((s64)page->index << PAGE_CACHE_SHIFT) + to > vi->i_size) {
// TODO: Implement resize...
// pos = ((s64)page->index << PAGE_CACHE_SHIFT) + to;
// vi->i_size = pos;
// mark_inode_dirty(vi);
// Should never get here!
ntfs_error(vi->i_sb, "Writing beyond the existing file size is "
"not supported yet. Sorry.");
return -EOPNOTSUPP;
}
if (!NInoAttr(ni))
base_ni = ni;
else
base_ni = ni->_INE(base_ntfs_ino);
/* Map, pin, and lock the mft record. */
m = map_mft_record(base_ni);
if (unlikely(IS_ERR(m))) {
err = PTR_ERR(m);
m = NULL;
ctx = NULL;
goto err_out;
}
ctx = get_attr_search_ctx(base_ni, m);
if (unlikely(!ctx)) {
err = -ENOMEM;
goto err_out;
}
if (unlikely(!lookup_attr(ni->type, ni->name, ni->name_len,
IGNORE_CASE, 0, NULL, 0, ctx))) {
err = -ENOENT;
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->_ARA(value_length));
if (unlikely(vi->i_size != attr_len)) {
ntfs_error(vi->i_sb, "BUG()! i_size (0x%Lx) 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%Lx) > attr_len (0x%x)"
". Aborting write.", attr_pos, attr_len);
err = -EIO;
goto err_out;
}
bytes = attr_len - attr_pos;
if (unlikely(bytes > PAGE_CACHE_SIZE))
bytes = PAGE_CACHE_SIZE;
/*
* Calculate the address of the attribute value corresponding to the
* beginning of the current data @page.
*/
kattr = (u8*)ctx->attr + le16_to_cpu(ctx->attr->_ARA(value_offset)) +
attr_pos;
kaddr = kmap_atomic(page, KM_USER0);
/* Copy the received data from the page to the mft record. */
memcpy(kattr + from, kaddr + from, to - from);
flush_dcache_mft_record_page(ctx->ntfs_ino);
if (!PageUptodate(page)) {
/*
* Bring the out of bounds area(s) uptodate by copying data
* from the mft record to the page.
*/
if (from > 0)
memcpy(kaddr, kattr, from);
if (to < bytes)
memcpy(kaddr + to, kattr + to, bytes - to);
/* Zero the region outside the end of the attribute value. */
if (likely(bytes < PAGE_CACHE_SIZE))
memset(kaddr + bytes, 0, PAGE_CACHE_SIZE - bytes);
/*
* The probability of not having done any of the above is
* extremely small, so we just flush unconditionally.
*/
flush_dcache_page(page);
SetPageUptodate(page);
}
kunmap_atomic(kaddr, KM_USER0);
// TODO: Mark mft record dirty so it gets written back.
ntfs_error(vi->i_sb, "Writing to resident files is not supported yet. "
"Wrote to memory only...");
put_attr_search_ctx(ctx);
unmap_mft_record(base_ni);
ntfs_debug("Done.");
return 0;
err_out:
if (err == -ENOMEM) {
ntfs_warning(vi->i_sb, "Error allocating memory required to "
"commit the write.");
if (PageUptodate(page)) {
ntfs_warning(vi->i_sb, "Page is uptodate, setting "
"dirty so the write will be retried "
"later on by the VM.");
/*
* Put the page on mapping->dirty_pages, but leave its
* buffer's dirty state as-is.
*/
__set_page_dirty_nobuffers(page);
err = 0;
} else
ntfs_error(vi->i_sb, "Page is not uptodate. Written "
"data has been lost. )-:");
} else {
ntfs_error(vi->i_sb, "Resident attribute write failed with "
"error %i. Setting page error flag.", -err);
SetPageError(page);
}
if (ctx)
put_attr_search_ctx(ctx);
if (m)
unmap_mft_record(base_ni);
return err;
}
#endif /* NTFS_RW */
/**
......@@ -1008,6 +1773,9 @@ struct address_space_operations ntfs_aops = {
disk request queue. */
#ifdef NTFS_RW
.writepage = ntfs_writepage, /* Write dirty page to disk. */
.prepare_write = ntfs_prepare_write, /* Prepare page and buffers
ready to receive data. */
.commit_write = ntfs_commit_write, /* Commit received data. */
#endif
};
fs/ntfs/attrib.c
View file @ e9042fae
......@@ -1182,8 +1182,9 @@ BOOL find_attr(const ATTR_TYPES type, const uchar_t *name, const u32 name_len,
else {
register int rc;
rc = memcmp(val, (u8*)a +le16_to_cpu(a->_ARA(value_offset)),
min(val_len, le32_to_cpu(a->_ARA(value_length))));
rc = memcmp(val, (u8*)a + le16_to_cpu(
a->_ARA(value_offset)), min(val_len,
le32_to_cpu(a->_ARA(value_length))));
/*
* If @val collates before the current attribute's
* value, there is no matching attribute.
......
fs/ntfs/file.c
View file @ e9042fae
......@@ -51,6 +51,9 @@ static int ntfs_file_open(struct inode *vi, struct file *filp)
struct file_operations ntfs_file_ops = {
.llseek = generic_file_llseek, /* Seek inside file. */
.read = generic_file_read, /* Read from file. */
#ifdef NTFS_RW
.write = generic_file_write, /* Write to a file. */
#endif
.mmap = generic_file_mmap, /* Mmap file. */
.sendfile = generic_file_sendfile,/* Zero-copy data send with the
data source being on the
......
fs/ntfs/mft.c
View file @ e9042fae
......@@ -98,7 +98,7 @@ int format_mft_record(ntfs_inode *ni, MFT_RECORD *mft_rec)
}
/**
* From fs/ntfs/aops.c
* ntfs_readpage - external declaration, function is in fs/ntfs/aops.c
*/
extern int ntfs_readpage(struct file *, struct page *);
......@@ -109,12 +109,9 @@ extern int ntfs_readpage(struct file *, struct page *);
* ntfs_map_page() in map_mft_record_page().
*/
struct address_space_operations ntfs_mft_aops = {
.writepage = NULL, /* Write dirty page to disk. */
.readpage = ntfs_readpage, /* Fill page with data. */
.sync_page = block_sync_page, /* Currently, just unplugs the
disk request queue. */
.prepare_write = NULL, /* . */
.commit_write = NULL, /* . */
};
/**
......
fs/ntfs/mft.h
View file @ e9042fae
......@@ -43,5 +43,19 @@ static inline void unmap_extent_mft_record(ntfs_inode *ni)
return;
}
/*
* flush_dcache_mft_record_page - flush_dcache_page() for mft records
* @ni: ntfs inode structure of mft record
*
* Call flush_dcache_page() for the page in which an mft record resides.
*
* This must be called every time an mft record is modified, just after the
* modification.
*/
static inline void flush_dcache_mft_record_page(ntfs_inode *ni)
{
flush_dcache_page(ni->page);
}
#endif /* _LINUX_NTFS_MFT_H */
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