1 files changed, 278 insertions, 177 deletions

diff --git a/fs/ntfs/aops.c b/fs/ntfs/aops.c
index 45d56e41ed98..b6cc8cf24626 100644
--- a/fs/ntfs/aops.c
+++ b/fs/ntfs/aops.c
@@ -2,7 +2,7 @@
  * aops.c - NTFS kernel address space operations and page cache handling.
  *          Part of the Linux-NTFS project.
  *
- * Copyright (c) 2001-2004 Anton Altaparmakov
+ * Copyright (c) 2001-2005 Anton Altaparmakov
  * Copyright (c) 2002 Richard Russon
  *
  * This program/include file is free software; you can redistribute it and/or
@@ -27,6 +27,7 @@
 #include <linux/swap.h>
 #include <linux/buffer_head.h>
 #include <linux/writeback.h>
+#include <linux/bit_spinlock.h>
 
 #include "aops.h"
 #include "attrib.h"
@@ -55,9 +56,8 @@
  */
 static void ntfs_end_buffer_async_read(struct buffer_head *bh, int uptodate)
 {
-        static DEFINE_SPINLOCK(page_uptodate_lock);
         unsigned long flags;
-        struct buffer_head *tmp;
+        struct buffer_head *first, *tmp;
         struct page *page;
         ntfs_inode *ni;
         int page_uptodate = 1;
@@ -66,19 +66,22 @@ static void ntfs_end_buffer_async_read(struct buffer_head *bh, int uptodate)
         ni = NTFS_I(page->mapping->host);
 
         if (likely(uptodate)) {
-                s64 file_ofs;
+                s64 file_ofs, initialized_size;
 
                 set_buffer_uptodate(bh);
 
                 file_ofs = ((s64)page->index << PAGE_CACHE_SHIFT) +
                                 bh_offset(bh);
+                read_lock_irqsave(&ni->size_lock, flags);
+                initialized_size = ni->initialized_size;
+                read_unlock_irqrestore(&ni->size_lock, flags);
                 /* Check for the current buffer head overflowing. */
-                if (file_ofs + bh->b_size > ni->initialized_size) {
+                if (file_ofs + bh->b_size > initialized_size) {
                         char *addr;
                         int ofs = 0;
 
-                        if (file_ofs < ni->initialized_size)
-                                ofs = ni->initialized_size - file_ofs;
+                        if (file_ofs < initialized_size)
+                                ofs = initialized_size - file_ofs;
                         addr = kmap_atomic(page, KM_BIO_SRC_IRQ);
                         memset(addr + bh_offset(bh) + ofs, 0, bh->b_size - ofs);
                         flush_dcache_page(page);
@@ -86,11 +89,13 @@ static void ntfs_end_buffer_async_read(struct buffer_head *bh, int uptodate)
                 }
         } else {
                 clear_buffer_uptodate(bh);
+                SetPageError(page);
                 ntfs_error(ni->vol->sb, "Buffer I/O error, logical block %llu.",
                                 (unsigned long long)bh->b_blocknr);
-                SetPageError(page);
         }
-        spin_lock_irqsave(&page_uptodate_lock, flags);
+        first = page_buffers(page);
+        local_irq_save(flags);
+        bit_spin_lock(BH_Uptodate_Lock, &first->b_state);
         clear_buffer_async_read(bh);
         unlock_buffer(bh);
         tmp = bh;
@@ -105,7 +110,8 @@ static void ntfs_end_buffer_async_read(struct buffer_head *bh, int uptodate)
                 }
                 tmp = tmp->b_this_page;
         } while (tmp != bh);
-        spin_unlock_irqrestore(&page_uptodate_lock, flags);
+        bit_spin_unlock(BH_Uptodate_Lock, &first->b_state);
+        local_irq_restore(flags);
         /*
          * If none of the buffers had errors then we can set the page uptodate,
          * but we first have to perform the post read mst fixups, if the
@@ -132,13 +138,14 @@ static void ntfs_end_buffer_async_read(struct buffer_head *bh, int uptodate)
                                         i * rec_size), rec_size);
                 flush_dcache_page(page);
                 kunmap_atomic(addr, KM_BIO_SRC_IRQ);
-                if (likely(!PageError(page) && page_uptodate))
+                if (likely(page_uptodate && !PageError(page)))
                         SetPageUptodate(page);
         }
         unlock_page(page);
         return;
 still_busy:
-        spin_unlock_irqrestore(&page_uptodate_lock, flags);
+        bit_spin_unlock(BH_Uptodate_Lock, &first->b_state);
+        local_irq_restore(flags);
         return;
 }
 
@@ -168,6 +175,7 @@ static int ntfs_read_block(struct page *page)
         runlist_element *rl;
         struct buffer_head *bh, *head, *arr[MAX_BUF_PER_PAGE];
         sector_t iblock, lblock, zblock;
+        unsigned long flags;
         unsigned int blocksize, vcn_ofs;
         int i, nr;
         unsigned char blocksize_bits;
@@ -181,23 +189,28 @@ static int ntfs_read_block(struct page *page)
         blocksize_bits = VFS_I(ni)->i_blkbits;
         blocksize = 1 << blocksize_bits;
 
-        if (!page_has_buffers(page))
+        if (!page_has_buffers(page)) {
                 create_empty_buffers(page, blocksize, 0);
-        bh = head = page_buffers(page);
-        if (unlikely(!bh)) {
-                unlock_page(page);
-                return -ENOMEM;
+                if (unlikely(!page_has_buffers(page))) {
+                        unlock_page(page);
+                        return -ENOMEM;
+                }
         }
+        bh = head = page_buffers(page);
+        BUG_ON(!bh);
 
         iblock = (s64)page->index << (PAGE_CACHE_SHIFT - blocksize_bits);
+        read_lock_irqsave(&ni->size_lock, flags);
         lblock = (ni->allocated_size + blocksize - 1) >> blocksize_bits;
         zblock = (ni->initialized_size + blocksize - 1) >> blocksize_bits;
+        read_unlock_irqrestore(&ni->size_lock, flags);
 
         /* Loop through all the buffers in the page. */
         rl = NULL;
         nr = i = 0;
         do {
                 u8 *kaddr;
+                int err;
 
                 if (unlikely(buffer_uptodate(bh)))
                         continue;
@@ -205,6 +218,7 @@ static int ntfs_read_block(struct page *page)
                         arr[nr++] = bh;
                         continue;
                 }
+                err = 0;
                 bh->b_bdev = vol->sb->s_bdev;
                 /* Is the block within the allowed limits? */
                 if (iblock < lblock) {
@@ -246,7 +260,6 @@ lock_retry_remap:
                                 goto handle_hole;
                         /* If first try and runlist unmapped, map and retry. */
                         if (!is_retry && lcn == LCN_RL_NOT_MAPPED) {
-                                int err;
                                 is_retry = TRUE;
                                 /*
                                  * Attempt to map runlist, dropping lock for
@@ -257,19 +270,30 @@ lock_retry_remap:
                                 if (likely(!err))
                                         goto lock_retry_remap;
                                 rl = NULL;
-                                lcn = err;
+                        } else if (!rl)
+                                up_read(&ni->runlist.lock);
+                        /*
+                         * If buffer is outside the runlist, treat it as a
+                         * hole.  This can happen due to concurrent truncate
+                         * for example.
+                         */
+                        if (err == -ENOENT || lcn == LCN_ENOENT) {
+                                err = 0;
+                                goto handle_hole;
                         }
                         /* Hard error, zero out region. */
+                        if (!err)
+                                err = -EIO;
                         bh->b_blocknr = -1;
                         SetPageError(page);
                         ntfs_error(vol->sb, "Failed to read from inode 0x%lx, "
                                         "attribute type 0x%x, vcn 0x%llx, "
                                         "offset 0x%x because its location on "
                                         "disk could not be determined%s "
-                                        "(error code %lli).", ni->mft_no,
+                                        "(error code %i).", ni->mft_no,
                                         ni->type, (unsigned long long)vcn,
                                         vcn_ofs, is_retry ? " even after "
-                                        "retrying" : "", (long long)lcn);
+                                        "retrying" : "", err);
                 }
                 /*
                  * Either iblock was outside lblock limits or
@@ -282,9 +306,10 @@ handle_hole:
 handle_zblock:
                 kaddr = kmap_atomic(page, KM_USER0);
                 memset(kaddr + i * blocksize, 0, blocksize);
-                flush_dcache_page(page);
                 kunmap_atomic(kaddr, KM_USER0);
-                set_buffer_uptodate(bh);
+                flush_dcache_page(page);
+                if (likely(!err))
+                        set_buffer_uptodate(bh);
         } while (i++, iblock++, (bh = bh->b_this_page) != head);
 
         /* Release the lock if we took it. */
@@ -341,14 +366,15 @@ handle_zblock:
  */
 static int ntfs_readpage(struct file *file, struct page *page)
 {
-        loff_t i_size;
         ntfs_inode *ni, *base_ni;
         u8 *kaddr;
         ntfs_attr_search_ctx *ctx;
         MFT_RECORD *mrec;
+        unsigned long flags;
         u32 attr_len;
         int err = 0;
 
+retry_readpage:
         BUG_ON(!PageLocked(page));
         /*
          * This can potentially happen because we clear PageUptodate() during
@@ -359,33 +385,40 @@ static int ntfs_readpage(struct file *file, struct page *page)
                 return 0;
         }
         ni = NTFS_I(page->mapping->host);
-
+        /*
+         * Only $DATA attributes can be encrypted and only unnamed $DATA
+         * attributes can be compressed.  Index root can have the flags set but
+         * this means to create compressed/encrypted files, not that the
+         * attribute is compressed/encrypted.
+         */
+        if (ni->type != AT_INDEX_ROOT) {
+                /* If attribute is encrypted, deny access, just like NT4. */
+                if (NInoEncrypted(ni)) {
+                        BUG_ON(ni->type != AT_DATA);
+                        err = -EACCES;
+                        goto err_out;
+                }
+                /* Compressed data streams are handled in compress.c. */
+                if (NInoNonResident(ni) && NInoCompressed(ni)) {
+                        BUG_ON(ni->type != AT_DATA);
+                        BUG_ON(ni->name_len);
+                        return ntfs_read_compressed_block(page);
+                }
+        }
         /* NInoNonResident() == NInoIndexAllocPresent() */
         if (NInoNonResident(ni)) {
-                /*
-                 * Only unnamed $DATA attributes can be compressed or
-                 * encrypted.
-                 */
-                if (ni->type == AT_DATA && !ni->name_len) {
-                        /* If file is encrypted, deny access, just like NT4. */
-                        if (NInoEncrypted(ni)) {
-                                err = -EACCES;
-                                goto err_out;
-                        }
-                        /* Compressed data streams are handled in compress.c. */
-                        if (NInoCompressed(ni))
-                                return ntfs_read_compressed_block(page);
-                }
-                /* Normal data stream. */
+                /* Normal, non-resident data stream. */
                 return ntfs_read_block(page);
         }
         /*
          * 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.
+         * index above 0.  Note the attribute can actually be marked compressed
+         * but if it is resident the actual data is not compressed so we are
+         * ok to ignore the compressed flag here.
          */
-        if (unlikely(page->index > 0 || !i_size_read(VFS_I(ni)))) {
+        if (unlikely(page->index > 0)) {
                 kaddr = kmap_atomic(page, KM_USER0);
                 memset(kaddr, 0, PAGE_CACHE_SIZE);
                 flush_dcache_page(page);
@@ -402,6 +435,14 @@ static int ntfs_readpage(struct file *file, struct page *page)
                 err = PTR_ERR(mrec);
                 goto err_out;
         }
+        /*
+         * If a parallel write made the attribute non-resident, drop the mft
+         * record and retry the readpage.
+         */
+        if (unlikely(NInoNonResident(ni))) {
+                unmap_mft_record(base_ni);
+                goto retry_readpage;
+        }
         ctx = ntfs_attr_get_search_ctx(base_ni, mrec);
         if (unlikely(!ctx)) {
                 err = -ENOMEM;
@@ -412,9 +453,10 @@ static int ntfs_readpage(struct file *file, struct page *page)
         if (unlikely(err))
                 goto put_unm_err_out;
         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;
+        read_lock_irqsave(&ni->size_lock, flags);
+        if (unlikely(attr_len > ni->initialized_size))
+                attr_len = ni->initialized_size;
+        read_unlock_irqrestore(&ni->size_lock, flags);
         kaddr = kmap_atomic(page, KM_USER0);
         /* Copy the data to the page. */
         memcpy(kaddr, (u8*)ctx->attr +
@@ -463,12 +505,15 @@ static int ntfs_write_block(struct page *page, struct writeback_control *wbc)
 {
         VCN vcn;
         LCN lcn;
+        s64 initialized_size;
+        loff_t i_size;
         sector_t block, dblock, iblock;
         struct inode *vi;
         ntfs_inode *ni;
         ntfs_volume *vol;
         runlist_element *rl;
         struct buffer_head *bh, *head;
+        unsigned long flags;
         unsigned int blocksize, vcn_ofs;
         int err;
         BOOL need_end_writeback;
@@ -491,30 +536,37 @@ static int ntfs_write_block(struct page *page, struct writeback_control *wbc)
                 BUG_ON(!PageUptodate(page));
                 create_empty_buffers(page, blocksize,
                                 (1 << BH_Uptodate) | (1 << BH_Dirty));
+                if (unlikely(!page_has_buffers(page))) {
+                        ntfs_warning(vol->sb, "Error allocating page "
+                                        "buffers.  Redirtying page so we try "
+                                        "again later.");
+                        /*
+                         * Put the page back on mapping->dirty_pages, but leave
+                         * its buffers' dirty state as-is.
+                         */
+                        redirty_page_for_writepage(wbc, page);
+                        unlock_page(page);
+                        return 0;
+                }
         }
         bh = head = page_buffers(page);
-        if (unlikely(!bh)) {
-                ntfs_warning(vol->sb, "Error allocating page buffers. "
-                                "Redirtying page so we try again later.");
-                /*
-                 * Put the page back on mapping->dirty_pages, but leave its
-                 * buffer's dirty state as-is.
-                 */
-                redirty_page_for_writepage(wbc, page);
-                unlock_page(page);
-                return 0;
-        }
+        BUG_ON(!bh);
 
         /* NOTE: Different naming scheme to ntfs_read_block()! */
 
         /* The first block in the page. */
         block = (s64)page->index << (PAGE_CACHE_SHIFT - blocksize_bits);
 
+        read_lock_irqsave(&ni->size_lock, flags);
+        i_size = i_size_read(vi);
+        initialized_size = ni->initialized_size;
+        read_unlock_irqrestore(&ni->size_lock, flags);
+
         /* The first out of bounds block for the data size. */
-        dblock = (vi->i_size + blocksize - 1) >> blocksize_bits;
+        dblock = (i_size + blocksize - 1) >> blocksize_bits;
 
         /* The last (fully or partially) initialized block. */
-        iblock = ni->initialized_size >> blocksize_bits;
+        iblock = initialized_size >> blocksize_bits;
 
         /*
          * Be very careful.  We have no exclusion from __set_page_dirty_buffers
@@ -559,7 +611,7 @@ static int ntfs_write_block(struct page *page, struct writeback_control *wbc)
 
                 /* Make sure we have enough initialized size. */
                 if (unlikely((block >= iblock) &&
-                                (ni->initialized_size < vi->i_size))) {
+                                (initialized_size < i_size))) {
                         /*
                          * If this page is fully outside initialized size, zero
                          * out all pages between the current initialized size
@@ -645,6 +697,27 @@ lock_retry_remap:
                 }
                 /* It is a hole, need to instantiate it. */
                 if (lcn == LCN_HOLE) {
+                        u8 *kaddr;
+                        unsigned long *bpos, *bend;
+
+                        /* Check if the buffer is zero. */
+                        kaddr = kmap_atomic(page, KM_USER0);
+                        bpos = (unsigned long *)(kaddr + bh_offset(bh));
+                        bend = (unsigned long *)((u8*)bpos + blocksize);
+                        do {
+                                if (unlikely(*bpos))
+                                        break;
+                        } while (likely(++bpos < bend));
+                        kunmap_atomic(kaddr, KM_USER0);
+                        if (bpos == bend) {
+                                /*
+                                 * Buffer is zero and sparse, no need to write
+                                 * it.
+                                 */
+                                bh->b_blocknr = -1;
+                                clear_buffer_dirty(bh);
+                                continue;
+                        }
                         // TODO: Instantiate the hole.
                         // clear_buffer_new(bh);
                         // unmap_underlying_metadata(bh->b_bdev, bh->b_blocknr);
@@ -665,19 +738,37 @@ lock_retry_remap:
                         if (likely(!err))
                                 goto lock_retry_remap;
                         rl = NULL;
-                        lcn = err;
+                } else if (!rl)
+                        up_read(&ni->runlist.lock);
+                /*
+                 * If buffer is outside the runlist, truncate has cut it out
+                 * of the runlist.  Just clean and clear the buffer and set it
+                 * uptodate so it can get discarded by the VM.
+                 */
+                if (err == -ENOENT || lcn == LCN_ENOENT) {
+                        u8 *kaddr;
+
+                        bh->b_blocknr = -1;
+                        clear_buffer_dirty(bh);
+                        kaddr = kmap_atomic(page, KM_USER0);
+                        memset(kaddr + bh_offset(bh), 0, blocksize);
+                        kunmap_atomic(kaddr, KM_USER0);
+                        flush_dcache_page(page);
+                        set_buffer_uptodate(bh);
+                        err = 0;
+                        continue;
                 }
                 /* Failed to map the buffer, even after retrying. */
+                if (!err)
+                        err = -EIO;
                 bh->b_blocknr = -1;
                 ntfs_error(vol->sb, "Failed to write to inode 0x%lx, "
                                 "attribute type 0x%x, vcn 0x%llx, offset 0x%x "
                                 "because its location on disk could not be "
-                                "determined%s (error code %lli).", ni->mft_no,
+                                "determined%s (error code %i).", ni->mft_no,
                                 ni->type, (unsigned long long)vcn,
                                 vcn_ofs, is_retry ? " even after "
-                                "retrying" : "", (long long)lcn);
-                if (!err)
-                        err = -EIO;
+                                "retrying" : "", err);
                 break;
         } while (block++, (bh = bh->b_this_page) != head);
 
@@ -688,7 +779,7 @@ lock_retry_remap:
         /* For the error case, need to reset bh to the beginning. */
         bh = head;
 
-        /* Just an optimization, so ->readpage() isn't called later. */
+        /* Just an optimization, so ->readpage() is not called later. */
         if (unlikely(!PageUptodate(page))) {
                 int uptodate = 1;
                 do {
@@ -704,7 +795,6 @@ lock_retry_remap:
 
         /* Setup all mapped, dirty buffers for async write i/o. */
         do {
-                get_bh(bh);
                 if (buffer_mapped(bh) && buffer_dirty(bh)) {
                         lock_buffer(bh);
                         if (test_clear_buffer_dirty(bh)) {
@@ -742,14 +832,8 @@ lock_retry_remap:
 
         BUG_ON(PageWriteback(page));
         set_page_writeback(page);       /* Keeps try_to_free_buffers() away. */
-        unlock_page(page);
 
-        /*
-         * Submit the prepared buffers for i/o. Note the page is unlocked,
-         * and the async write i/o completion handler can end_page_writeback()
-         * at any time after the *first* submit_bh(). So the buffers can then
-         * disappear...
-         */
+        /* Submit the prepared buffers for i/o. */
         need_end_writeback = TRUE;
         do {
                 struct buffer_head *next = bh->b_this_page;
@@ -757,9 +841,9 @@ lock_retry_remap:
                         submit_bh(WRITE, bh);
                         need_end_writeback = FALSE;
                 }
-                put_bh(bh);
                 bh = next;
         } while (bh != head);
+        unlock_page(page);
 
         /* If no i/o was started, need to end_page_writeback(). */
         if (unlikely(need_end_writeback))
@@ -801,17 +885,15 @@ static int ntfs_write_mst_block(struct page *page,
         ntfs_inode *ni = NTFS_I(vi);
         ntfs_volume *vol = ni->vol;
         u8 *kaddr;
-        unsigned char bh_size_bits = vi->i_blkbits;
-        unsigned int bh_size = 1 << bh_size_bits;
         unsigned int rec_size = ni->itype.index.block_size;
         ntfs_inode *locked_nis[PAGE_CACHE_SIZE / rec_size];
         struct buffer_head *bh, *head, *tbh, *rec_start_bh;
-        int max_bhs = PAGE_CACHE_SIZE / bh_size;
-        struct buffer_head *bhs[max_bhs];
+        struct buffer_head *bhs[MAX_BUF_PER_PAGE];
         runlist_element *rl;
-        int i, nr_locked_nis, nr_recs, nr_bhs, bhs_per_rec, err, err2;
-        unsigned rec_size_bits;
+        int i, nr_locked_nis, nr_recs, nr_bhs, max_bhs, bhs_per_rec, err, err2;
+        unsigned bh_size, rec_size_bits;
         BOOL sync, is_mft, page_is_dirty, rec_is_dirty;
+        unsigned char bh_size_bits;
 
         ntfs_debug("Entering for inode 0x%lx, attribute type 0x%x, page index "
                         "0x%lx.", vi->i_ino, ni->type, page->index);
@@ -826,13 +908,16 @@ static int ntfs_write_mst_block(struct page *page,
          */
         BUG_ON(!(is_mft || S_ISDIR(vi->i_mode) ||
                         (NInoAttr(ni) && ni->type == AT_INDEX_ALLOCATION)));
+        bh_size_bits = vi->i_blkbits;
+        bh_size = 1 << bh_size_bits;
+        max_bhs = PAGE_CACHE_SIZE / bh_size;
         BUG_ON(!max_bhs);
+        BUG_ON(max_bhs > MAX_BUF_PER_PAGE);
 
         /* Were we called for sync purposes? */
         sync = (wbc->sync_mode == WB_SYNC_ALL);
 
         /* Make sure we have mapped buffers. */
-        BUG_ON(!page_has_buffers(page));
         bh = head = page_buffers(page);
         BUG_ON(!bh);
 
@@ -846,7 +931,7 @@ static int ntfs_write_mst_block(struct page *page,
                         (PAGE_CACHE_SHIFT - bh_size_bits);
 
         /* The first out of bounds block for the data size. */
-        dblock = (vi->i_size + bh_size - 1) >> bh_size_bits;
+        dblock = (i_size_read(vi) + bh_size - 1) >> bh_size_bits;
 
         rl = NULL;
         err = err2 = nr_bhs = nr_recs = nr_locked_nis = 0;
@@ -858,6 +943,7 @@ static int ntfs_write_mst_block(struct page *page,
                 if (likely(block < rec_block)) {
                         if (unlikely(block >= dblock)) {
                                 clear_buffer_dirty(bh);
+                                set_buffer_uptodate(bh);
                                 continue;
                         }
                         /*
@@ -895,6 +981,7 @@ static int ntfs_write_mst_block(struct page *page,
                         LCN lcn;
                         unsigned int vcn_ofs;
 
+                        bh->b_bdev = vol->sb->s_bdev;
                         /* Obtain the vcn and offset of the current block. */
                         vcn = (VCN)block << bh_size_bits;
                         vcn_ofs = vcn & vol->cluster_size_mask;
@@ -938,8 +1025,11 @@ lock_retry_remap:
                                         if (err2 == -ENOMEM)
                                                 page_is_dirty = TRUE;
                                         lcn = err2;
-                                } else
+                                } else {
                                         err2 = -EIO;
+                                        if (!rl)
+                                                up_read(&ni->runlist.lock);
+                                }
                                 /* Hard error.  Abort writing this record. */
                                 if (!err || err == -ENOMEM)
                                         err = err2;
@@ -949,7 +1039,8 @@ lock_retry_remap:
                                                 "attribute type 0x%x) because "
                                                 "its location on disk could "
                                                 "not be determined (error "
-                                                "code %lli).", (s64)block <<
+                                                "code %lli).",
+                                                (long long)block <<
                                                 bh_size_bits >>
                                                 vol->mft_record_size_bits,
                                                 ni->mft_no, ni->type,
@@ -1223,19 +1314,17 @@ done:
 static int ntfs_writepage(struct page *page, struct writeback_control *wbc)
 {
         loff_t i_size;
-        struct inode *vi;
-        ntfs_inode *ni, *base_ni;
+        struct inode *vi = page->mapping->host;
+        ntfs_inode *base_ni = NULL, *ni = NTFS_I(vi);
         char *kaddr;
-        ntfs_attr_search_ctx *ctx;
-        MFT_RECORD *m;
+        ntfs_attr_search_ctx *ctx = NULL;
+        MFT_RECORD *m = NULL;
         u32 attr_len;
         int err;
 
+retry_writepage:
         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)) {
@@ -1248,40 +1337,42 @@ static int ntfs_writepage(struct page *page, struct writeback_control *wbc)
                 ntfs_debug("Write outside i_size - truncated?");
                 return 0;
         }
-        ni = NTFS_I(vi);
-
+        /*
+         * Only $DATA attributes can be encrypted and only unnamed $DATA
+         * attributes can be compressed.  Index root can have the flags set but
+         * this means to create compressed/encrypted files, not that the
+         * attribute is compressed/encrypted.
+         */
+        if (ni->type != AT_INDEX_ROOT) {
+                /* If file is encrypted, deny access, just like NT4. */
+                if (NInoEncrypted(ni)) {
+                        unlock_page(page);
+                        BUG_ON(ni->type != AT_DATA);
+                        ntfs_debug("Denying write access to encrypted "
+                                        "file.");
+                        return -EACCES;
+                }
+                /* Compressed data streams are handled in compress.c. */
+                if (NInoNonResident(ni) && NInoCompressed(ni)) {
+                        BUG_ON(ni->type != AT_DATA);
+                        BUG_ON(ni->name_len);
+                        // TODO: Implement and replace this with
+                        // return ntfs_write_compressed_block(page);
+                        unlock_page(page);
+                        ntfs_error(vi->i_sb, "Writing to compressed files is "
+                                        "not supported yet.  Sorry.");
+                        return -EOPNOTSUPP;
+                }
+                // TODO: Implement and remove this check.
+                if (NInoNonResident(ni) && NInoSparse(ni)) {
+                        unlock_page(page);
+                        ntfs_error(vi->i_sb, "Writing to sparse files is not "
+                                        "supported yet.  Sorry.");
+                        return -EOPNOTSUPP;
+                }
+        }
         /* NInoNonResident() == NInoIndexAllocPresent() */
         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)) {
-                                unlock_page(page);
-                                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);
-                                unlock_page(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)) {
-                                unlock_page(page);
-                                ntfs_error(vi->i_sb, "Writing to sparse files "
-                                                "is not supported yet. Sorry.");
-                                return -EOPNOTSUPP;
-                        }
-                }
                 /* We have to zero every time due to mmap-at-end-of-file. */
                 if (page->index >= (i_size >> PAGE_CACHE_SHIFT)) {
                         /* The page straddles i_size. */
@@ -1294,14 +1385,16 @@ static int ntfs_writepage(struct page *page, struct writeback_control *wbc)
                 /* Handle mst protected attributes. */
                 if (NInoMstProtected(ni))
                         return ntfs_write_mst_block(page, wbc);
-                /* Normal data stream. */
+                /* Normal, non-resident data stream. */
                 return ntfs_write_block(page, wbc);
         }
         /*
-         * Attribute is resident, implying it is not compressed, encrypted,
-         * 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.
+         * Attribute is resident, implying it is not compressed, encrypted, 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.  Note the attribute can actually be
+         * marked compressed but if it is resident the actual data is not
+         * compressed so we are ok to ignore the compressed flag here.
          */
         BUG_ON(page_has_buffers(page));
         BUG_ON(!PageUptodate(page));
@@ -1326,6 +1419,14 @@ static int ntfs_writepage(struct page *page, struct writeback_control *wbc)
                 ctx = NULL;
                 goto err_out;
         }
+        /*
+         * If a parallel write made the attribute non-resident, drop the mft
+         * record and retry the writepage.
+         */
+        if (unlikely(NInoNonResident(ni))) {
+                unmap_mft_record(base_ni);
+                goto retry_writepage;
+        }
         ctx = ntfs_attr_get_search_ctx(base_ni, m);
         if (unlikely(!ctx)) {
                 err = -ENOMEM;
@@ -1342,40 +1443,21 @@ static int ntfs_writepage(struct page *page, struct writeback_control *wbc)
         BUG_ON(PageWriteback(page));
         set_page_writeback(page);
         unlock_page(page);
-
         /*
-         * Here, we don't need to zero the out of bounds area everytime because
-         * the below memcpy() already takes care of the mmap-at-end-of-file
-         * requirements. If the file is converted to a non-resident one, then
-         * the code path use is switched to the non-resident one where the
-         * zeroing happens on each ntfs_writepage() invocation.
-         *
-         * The above also applies nicely when i_size is decreased.
-         *
-         * When i_size is increased, the memory between the old and new i_size
-         * _must_ be zeroed (or overwritten with new data). Otherwise we will
-         * expose data to userspace/disk which should never have been exposed.
-         *
-         * FIXME: Ensure that i_size increases do the zeroing/overwriting and
-         * if we cannot guarantee that, then enable the zeroing below.  If the
-         * zeroing below is enabled, we MUST move the unlock_page() from above
-         * to after the kunmap_atomic(), i.e. just before the
-         * end_page_writeback().
-         * UPDATE: ntfs_prepare/commit_write() do the zeroing on i_size
-         * increases for resident attributes so those are ok.
-         * TODO: ntfs_truncate(), others?
+         * Here, we do not need to zero the out of bounds area everytime
+         * because the below memcpy() already takes care of the
+         * mmap-at-end-of-file requirements.  If the file is converted to a
+         * non-resident one, then the code path use is switched to the
+         * non-resident one where the zeroing happens on each ntfs_writepage()
+         * invocation.
          */
-
         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);
+        i_size = i_size_read(vi);
         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;
+                ctx->attr->data.resident.value_length = cpu_to_le32(attr_len);
         }
+        kaddr = kmap_atomic(page, KM_USER0);
         /* Copy the data from the page to the mft record. */
         memcpy((u8*)ctx->attr +
                         le16_to_cpu(ctx->attr->data.resident.value_offset),
@@ -1405,8 +1487,10 @@ err_out:
                 err = 0;
         } else {
                 ntfs_error(vi->i_sb, "Resident attribute write failed with "
-                                "error %i.  Setting page error flag.", err);
+                                "error %i.", err);
                 SetPageError(page);
+                NVolSetErrors(ni->vol);
+                make_bad_inode(vi);
         }
         unlock_page(page);
         if (ctx)
@@ -1425,12 +1509,15 @@ static int ntfs_prepare_nonresident_write(struct page *page,
 {
         VCN vcn;
         LCN lcn;
+        s64 initialized_size;
+        loff_t i_size;
         sector_t block, ablock, iblock;
         struct inode *vi;
         ntfs_inode *ni;
         ntfs_volume *vol;
         runlist_element *rl;
         struct buffer_head *bh, *head, *wait[2], **wait_bh = wait;
+        unsigned long flags;
         unsigned int vcn_ofs, block_start, block_end, blocksize;
         int err;
         BOOL is_retry;
@@ -1462,16 +1549,20 @@ static int ntfs_prepare_nonresident_write(struct page *page,
         /* The first block in the page. */
         block = (s64)page->index << (PAGE_CACHE_SHIFT - blocksize_bits);
 
+        read_lock_irqsave(&ni->size_lock, flags);
         /*
-         * The first out of bounds block for the allocated size. No need to
+         * 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;
+        i_size = i_size_read(vi);
+        initialized_size = ni->initialized_size;
+        read_unlock_irqrestore(&ni->size_lock, flags);
 
         /* The last (fully or partially) initialized block. */
-        iblock = ni->initialized_size >> blocksize_bits;
+        iblock = initialized_size >> blocksize_bits;
 
         /* Loop through all the buffers in the page. */
         block_start = 0;
@@ -1518,7 +1609,7 @@ static int ntfs_prepare_nonresident_write(struct page *page,
                  * request, i.e. block < ablock is true.
                  */
                 if (unlikely((block >= iblock) &&
-                                (ni->initialized_size < vi->i_size))) {
+                                (initialized_size < i_size))) {
                         /*
                          * If this page is fully outside initialized size, zero
                          * out all pages between the current initialized size
@@ -1622,6 +1713,8 @@ lock_retry_remap:
                                                         "not supported yet. "
                                                         "Sorry.");
                                         err = -EOPNOTSUPP;
+                                        if (!rl)
+                                                up_read(&ni->runlist.lock);
                                         goto err_out;
                                 } else if (!is_retry &&
                                                 lcn == LCN_RL_NOT_MAPPED) {
@@ -1635,26 +1728,25 @@ lock_retry_remap:
                                         if (likely(!err))
                                                 goto lock_retry_remap;
                                         rl = NULL;
-                                        lcn = err;
-                                }
+                                } else if (!rl)
+                                        up_read(&ni->runlist.lock);
                                 /*
                                  * Failed to map the buffer, even after
                                  * retrying.
                                  */
+                                if (!err)
+                                        err = -EIO;
                                 bh->b_blocknr = -1;
                                 ntfs_error(vol->sb, "Failed to write to inode "
                                                 "0x%lx, attribute type 0x%x, "
                                                 "vcn 0x%llx, offset 0x%x "
                                                 "because its location on disk "
                                                 "could not be determined%s "
-                                                "(error code %lli).",
+                                                "(error code %i).",
                                                 ni->mft_no, ni->type,
                                                 (unsigned long long)vcn,
                                                 vcn_ofs, is_retry ? " even "
-                                                "after retrying" : "",
-                                                (long long)lcn);
-                                if (!err)
-                                        err = -EIO;
+                                                "after retrying" : "", err);
                                 goto err_out;
                         }
                         /* We now have a successful remap, i.e. lcn >= 0. */
@@ -1797,6 +1889,7 @@ static int ntfs_prepare_write(struct file *file, struct page *page,
                 unsigned from, unsigned to)
 {
         s64 new_size;
+        loff_t i_size;
         struct inode *vi = page->mapping->host;
         ntfs_inode *base_ni = NULL, *ni = NTFS_I(vi);
         ntfs_volume *vol = ni->vol;
@@ -1868,14 +1961,8 @@ static int ntfs_prepare_write(struct file *file, struct page *page,
         BUG_ON(page_has_buffers(page));
         new_size = ((s64)page->index << PAGE_CACHE_SHIFT) + to;
         /* If we do not need to resize the attribute allocation we are done. */
-        if (new_size <= vi->i_size)
+        if (new_size <= i_size_read(vi))
                 goto done;
-
-        // FIXME: We abort for now as this code is not safe.
-        ntfs_error(vi->i_sb, "Changing the file size is not supported yet.  "
-                        "Sorry.");
-        return -EOPNOTSUPP;
-
         /* Map, pin, and lock the (base) mft record. */
         if (!NInoAttr(ni))
                 base_ni = ni;
@@ -1904,7 +1991,15 @@ static int ntfs_prepare_write(struct file *file, struct page *page,
         a = ctx->attr;
         /* The total length of the attribute value. */
         attr_len = le32_to_cpu(a->data.resident.value_length);
-        BUG_ON(vi->i_size != attr_len);
+        /* Fix an eventual previous failure of ntfs_commit_write(). */
+        i_size = i_size_read(vi);
+        if (unlikely(attr_len > i_size)) {
+                attr_len = i_size;
+                a->data.resident.value_length = cpu_to_le32(attr_len);
+        }
+        /* If we do not need to resize the attribute allocation we are done. */
+        if (new_size <= attr_len)
+                goto done_unm;
         /* Check if new size is allowed in $AttrDef. */
         err = ntfs_attr_size_bounds_check(vol, ni->type, new_size);
         if (unlikely(err)) {
@@ -1962,6 +2057,7 @@ static int ntfs_prepare_write(struct file *file, struct page *page,
         }
         flush_dcache_mft_record_page(ctx->ntfs_ino);
         mark_mft_record_dirty(ctx->ntfs_ino);
+done_unm:
         ntfs_attr_put_search_ctx(ctx);
         unmap_mft_record(base_ni);
         /*
@@ -2047,7 +2143,7 @@ static int ntfs_commit_nonresident_write(struct page *page,
          * 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) {
+        if (pos > i_size_read(vi)) {
                 ntfs_error(vi->i_sb, "Writing beyond the existing file size is "
                                 "not supported yet.  Sorry.");
                 return -EOPNOTSUPP;
@@ -2183,9 +2279,13 @@ static int ntfs_commit_write(struct file *file, struct page *page,
         }
         kunmap_atomic(kaddr, KM_USER0);
         /* Update i_size if necessary. */
-        if (vi->i_size < attr_len) {
+        if (i_size_read(vi) < attr_len) {
+                unsigned long flags;
+
+                write_lock_irqsave(&ni->size_lock, flags);
                 ni->allocated_size = ni->initialized_size = attr_len;
                 i_size_write(vi, attr_len);
+                write_unlock_irqrestore(&ni->size_lock, flags);
         }
         /* Mark the mft record dirty, so it gets written back. */
         flush_dcache_mft_record_page(ctx->ntfs_ino);
@@ -2302,6 +2402,7 @@ void mark_ntfs_record_dirty(struct page *page, const unsigned int ofs) {
                         buffers_to_free = bh;
         }
         bh = head = page_buffers(page);
+        BUG_ON(!bh);
         do {
                 bh_ofs = bh_offset(bh);
                 if (bh_ofs + bh_size <= ofs)