NTFS: Use i_size_{read,write}() in fs/ntfs/{aops.c,mft.c} and protect

      access to the i_size and other size fields using the size_lock.

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

3 files changed, 156 insertions, 59 deletions

diff --git a/fs/ntfs/ChangeLog b/fs/ntfs/ChangeLog
index 445d421e961d..051c6818aad8 100644
--- a/fs/ntfs/ChangeLog
+++ b/fs/ntfs/ChangeLog
@@ -49,6 +49,8 @@ ToDo/Notes:
         - Minor optimization to fs/ntfs/super.c::ntfs_statfs() and its helpers.
         - Use i_size_read() in fs/ntfs/inode.c once and then use the cached
           value afterwards when reading the size of the bitmap inode.
+        - Use i_size_{read,write}() in fs/ntfs/{aops.c,mft.c} and protect
+          access to the i_size and other size fields using the size_lock.
 
 2.1.22 - Many bug and race fixes and error handling improvements.
 
diff --git a/fs/ntfs/aops.c b/fs/ntfs/aops.c
index 45d56e41ed98..a53212793809 100644
--- a/fs/ntfs/aops.c
+++ b/fs/ntfs/aops.c
@@ -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);
@@ -168,6 +171,7 @@ 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;
@@ -190,8 +194,10 @@ static int ntfs_read_block(struct page *page)
         }
 
         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;
@@ -463,12 +469,15 @@ 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;
@@ -510,11 +519,16 @@ static int ntfs_write_block(struct page *page, struct writeback_control *wbc)
         /* 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 +573,7 @@ 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
@@ -846,7 +860,7 @@ 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;
@@ -1367,7 +1381,7 @@ static int ntfs_writepage(struct page *page, struct writeback_control *wbc)
          */
 
         attr_len = le32_to_cpu(ctx->attr->data.resident.value_length);
-        i_size = i_size_read(VFS_I(ni));
+        i_size = i_size_read(vi);
         kaddr = kmap_atomic(page, KM_USER0);
         if (unlikely(attr_len > i_size)) {
                 /* Zero out of bounds area in the mft record. */
@@ -1425,12 +1439,15 @@ 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;
@@ -1462,6 +1479,7 @@ 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
          * round up as allocated_size is in multiples of cluster size and the
@@ -1470,8 +1488,12 @@ static int ntfs_prepare_nonresident_write(struct page *page,
          */
         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 +1540,7 @@ 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
@@ -1868,7 +1890,7 @@ 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.
@@ -1904,7 +1926,7 @@ 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);
+        BUG_ON(i_size_read(vi) != attr_len);
         /* Check if new size is allowed in $AttrDef. */
         err = ntfs_attr_size_bounds_check(vol, ni->type, new_size);
         if (unlikely(err)) {
@@ -2047,7 +2069,7 @@ 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 +2205,13 @@ 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);
diff --git a/fs/ntfs/mft.c b/fs/ntfs/mft.c
index dfa85ac2f8ba..20011e02f5b6 100644
--- a/fs/ntfs/mft.c
+++ b/fs/ntfs/mft.c
@@ -45,6 +45,7 @@
  */
 static inline MFT_RECORD *map_mft_record_page(ntfs_inode *ni)
 {
+        loff_t i_size;
         ntfs_volume *vol = ni->vol;
         struct inode *mft_vi = vol->mft_ino;
         struct page *page;
@@ -60,13 +61,14 @@ static inline MFT_RECORD *map_mft_record_page(ntfs_inode *ni)
         index = ni->mft_no << vol->mft_record_size_bits >> PAGE_CACHE_SHIFT;
         ofs = (ni->mft_no << vol->mft_record_size_bits) & ~PAGE_CACHE_MASK;
 
+        i_size = i_size_read(mft_vi);
         /* The maximum valid index into the page cache for $MFT's data. */
-        end_index = mft_vi->i_size >> PAGE_CACHE_SHIFT;
+        end_index = i_size >> PAGE_CACHE_SHIFT;
 
         /* If the wanted index is out of bounds the mft record doesn't exist. */
         if (unlikely(index >= end_index)) {
-                if (index > end_index || (mft_vi->i_size & ~PAGE_CACHE_MASK) <
-                                ofs + vol->mft_record_size) {
+                if (index > end_index || (i_size & ~PAGE_CACHE_MASK) < ofs +
+                                vol->mft_record_size) {
                         page = ERR_PTR(-ENOENT);
                         ntfs_error(vol->sb, "Attemt to read mft record 0x%lx, "
                                         "which is beyond the end of the mft.  "
@@ -1121,6 +1123,7 @@ static int ntfs_mft_bitmap_find_and_alloc_free_rec_nolock(ntfs_volume *vol,
                 ntfs_inode *base_ni)
 {
         s64 pass_end, ll, data_pos, pass_start, ofs, bit;
+        unsigned long flags;
         struct address_space *mftbmp_mapping;
         u8 *buf, *byte;
         struct page *page;
@@ -1134,9 +1137,13 @@ static int ntfs_mft_bitmap_find_and_alloc_free_rec_nolock(ntfs_volume *vol,
          * Set the end of the pass making sure we do not overflow the mft
          * bitmap.
          */
+        read_lock_irqsave(&NTFS_I(vol->mft_ino)->size_lock, flags);
         pass_end = NTFS_I(vol->mft_ino)->allocated_size >>
                         vol->mft_record_size_bits;
+        read_unlock_irqrestore(&NTFS_I(vol->mft_ino)->size_lock, flags);
+        read_lock_irqsave(&NTFS_I(vol->mftbmp_ino)->size_lock, flags);
         ll = NTFS_I(vol->mftbmp_ino)->initialized_size << 3;
+        read_unlock_irqrestore(&NTFS_I(vol->mftbmp_ino)->size_lock, flags);
         if (pass_end > ll)
                 pass_end = ll;
         pass = 1;
@@ -1263,6 +1270,7 @@ static int ntfs_mft_bitmap_extend_allocation_nolock(ntfs_volume *vol)
 {
         LCN lcn;
         s64 ll;
+        unsigned long flags;
         struct page *page;
         ntfs_inode *mft_ni, *mftbmp_ni;
         runlist_element *rl, *rl2 = NULL;
@@ -1286,8 +1294,10 @@ static int ntfs_mft_bitmap_extend_allocation_nolock(ntfs_volume *vol)
          * mft bitmap cannot be zero so we are ok to do this.
          * ntfs_find_vcn() returns the runlist locked on success.
          */
-        rl = ntfs_find_vcn(mftbmp_ni, (mftbmp_ni->allocated_size - 1) >>
-                        vol->cluster_size_bits, TRUE);
+        read_lock_irqsave(&mftbmp_ni->size_lock, flags);
+        ll = mftbmp_ni->allocated_size;
+        read_unlock_irqrestore(&mftbmp_ni->size_lock, flags);
+        rl = ntfs_find_vcn(mftbmp_ni, (ll - 1) >> vol->cluster_size_bits, TRUE);
         if (unlikely(IS_ERR(rl) || !rl->length || rl->lcn < 0)) {
                 ntfs_error(vol->sb, "Failed to determine last allocated "
                                 "cluster of mft bitmap attribute.");
@@ -1458,9 +1468,11 @@ static int ntfs_mft_bitmap_extend_allocation_nolock(ntfs_volume *vol)
                 }
                 a = ctx->attr;
         }
+        write_lock_irqsave(&mftbmp_ni->size_lock, flags);
         mftbmp_ni->allocated_size += vol->cluster_size;
         a->data.non_resident.allocated_size =
                         cpu_to_sle64(mftbmp_ni->allocated_size);
+        write_unlock_irqrestore(&mftbmp_ni->size_lock, flags);
         /* Ensure the changes make it to disk. */
         flush_dcache_mft_record_page(ctx->ntfs_ino);
         mark_mft_record_dirty(ctx->ntfs_ino);
@@ -1476,7 +1488,9 @@ restore_undo_alloc:
                         0, ctx)) {
                 ntfs_error(vol->sb, "Failed to find last attribute extent of "
                                 "mft bitmap attribute.%s", es);
+                write_lock_irqsave(&mftbmp_ni->size_lock, flags);
                 mftbmp_ni->allocated_size += vol->cluster_size;
+                write_unlock_irqrestore(&mftbmp_ni->size_lock, flags);
                 ntfs_attr_put_search_ctx(ctx);
                 unmap_mft_record(mft_ni);
                 up_write(&mftbmp_ni->runlist.lock);
@@ -1550,6 +1564,7 @@ undo_alloc:
 static int ntfs_mft_bitmap_extend_initialized_nolock(ntfs_volume *vol)
 {
         s64 old_data_size, old_initialized_size;
+        unsigned long flags;
         struct inode *mftbmp_vi;
         ntfs_inode *mft_ni, *mftbmp_ni;
         ntfs_attr_search_ctx *ctx;
@@ -1583,7 +1598,8 @@ static int ntfs_mft_bitmap_extend_initialized_nolock(ntfs_volume *vol)
                 goto put_err_out;
         }
         a = ctx->attr;
-        old_data_size = mftbmp_vi->i_size;
+        write_lock_irqsave(&mftbmp_ni->size_lock, flags);
+        old_data_size = i_size_read(mftbmp_vi);
         old_initialized_size = mftbmp_ni->initialized_size;
         /*
          * We can simply update the initialized_size before filling the space
@@ -1593,11 +1609,12 @@ static int ntfs_mft_bitmap_extend_initialized_nolock(ntfs_volume *vol)
         mftbmp_ni->initialized_size += 8;
         a->data.non_resident.initialized_size =
                         cpu_to_sle64(mftbmp_ni->initialized_size);
-        if (mftbmp_ni->initialized_size > mftbmp_vi->i_size) {
-                mftbmp_vi->i_size = mftbmp_ni->initialized_size;
+        if (mftbmp_ni->initialized_size > old_data_size) {
+                i_size_write(mftbmp_vi, mftbmp_ni->initialized_size);
                 a->data.non_resident.data_size =
-                                cpu_to_sle64(mftbmp_vi->i_size);
+                                cpu_to_sle64(mftbmp_ni->initialized_size);
         }
+        write_unlock_irqrestore(&mftbmp_ni->size_lock, flags);
         /* Ensure the changes make it to disk. */
         flush_dcache_mft_record_page(ctx->ntfs_ino);
         mark_mft_record_dirty(ctx->ntfs_ino);
@@ -1636,22 +1653,28 @@ unm_err_out:
                 goto err_out;
         }
         a = ctx->attr;
+        write_lock_irqsave(&mftbmp_ni->size_lock, flags);
         mftbmp_ni->initialized_size = old_initialized_size;
         a->data.non_resident.initialized_size =
                         cpu_to_sle64(old_initialized_size);
-        if (mftbmp_vi->i_size != old_data_size) {
-                mftbmp_vi->i_size = old_data_size;
+        if (i_size_read(mftbmp_vi) != old_data_size) {
+                i_size_write(mftbmp_vi, old_data_size);
                 a->data.non_resident.data_size = cpu_to_sle64(old_data_size);
         }
+        write_unlock_irqrestore(&mftbmp_ni->size_lock, flags);
         flush_dcache_mft_record_page(ctx->ntfs_ino);
         mark_mft_record_dirty(ctx->ntfs_ino);
         ntfs_attr_put_search_ctx(ctx);
         unmap_mft_record(mft_ni);
+#ifdef DEBUG
+        read_lock_irqsave(&mftbmp_ni->size_lock, flags);
         ntfs_debug("Restored status of mftbmp: allocated_size 0x%llx, "
                         "data_size 0x%llx, initialized_size 0x%llx.",
                         (long long)mftbmp_ni->allocated_size,
-                        (long long)mftbmp_vi->i_size,
+                        (long long)i_size_read(mftbmp_vi),
                         (long long)mftbmp_ni->initialized_size);
+        read_unlock_irqrestore(&mftbmp_ni->size_lock, flags);
+#endif /* DEBUG */
 err_out:
         return ret;
 }
@@ -1679,7 +1702,8 @@ static int ntfs_mft_data_extend_allocation_nolock(ntfs_volume *vol)
 {
         LCN lcn;
         VCN old_last_vcn;
-        s64 min_nr, nr, ll = 0;
+        s64 min_nr, nr, ll;
+        unsigned long flags;
         ntfs_inode *mft_ni;
         runlist_element *rl, *rl2;
         ntfs_attr_search_ctx *ctx = NULL;
@@ -1697,8 +1721,10 @@ static int ntfs_mft_data_extend_allocation_nolock(ntfs_volume *vol)
          * attribute cannot be zero so we are ok to do this.
          * ntfs_find_vcn() returns the runlist locked on success.
          */
-        rl = ntfs_find_vcn(mft_ni, (mft_ni->allocated_size - 1) >>
-                        vol->cluster_size_bits, TRUE);
+        read_lock_irqsave(&mft_ni->size_lock, flags);
+        ll = mft_ni->allocated_size;
+        read_unlock_irqrestore(&mft_ni->size_lock, flags);
+        rl = ntfs_find_vcn(mft_ni, (ll - 1) >> vol->cluster_size_bits, TRUE);
         if (unlikely(IS_ERR(rl) || !rl->length || rl->lcn < 0)) {
                 ntfs_error(vol->sb, "Failed to determine last allocated "
                                 "cluster of mft data attribute.");
@@ -1710,8 +1736,7 @@ static int ntfs_mft_data_extend_allocation_nolock(ntfs_volume *vol)
                 return ret;
         }
         lcn = rl->lcn + rl->length;
-        ntfs_debug("Last lcn of mft data attribute is 0x%llx.",
-                        (long long)lcn);
+        ntfs_debug("Last lcn of mft data attribute is 0x%llx.", (long long)lcn);
         /* Minimum allocation is one mft record worth of clusters. */
         min_nr = vol->mft_record_size >> vol->cluster_size_bits;
         if (!min_nr)
@@ -1721,12 +1746,13 @@ static int ntfs_mft_data_extend_allocation_nolock(ntfs_volume *vol)
         if (!nr)
                 nr = min_nr;
         /* Ensure we do not go above 2^32-1 mft records. */
-        if (unlikely((mft_ni->allocated_size +
-                        (nr << vol->cluster_size_bits)) >>
+        read_lock_irqsave(&mft_ni->size_lock, flags);
+        ll = mft_ni->allocated_size;
+        read_unlock_irqrestore(&mft_ni->size_lock, flags);
+        if (unlikely((ll + (nr << vol->cluster_size_bits)) >>
                         vol->mft_record_size_bits >= (1ll << 32))) {
                 nr = min_nr;
-                if (unlikely((mft_ni->allocated_size +
-                                (nr << vol->cluster_size_bits)) >>
+                if (unlikely((ll + (nr << vol->cluster_size_bits)) >>
                                 vol->mft_record_size_bits >= (1ll << 32))) {
                         ntfs_warning(vol->sb, "Cannot allocate mft record "
                                         "because the maximum number of inodes "
@@ -1875,9 +1901,11 @@ static int ntfs_mft_data_extend_allocation_nolock(ntfs_volume *vol)
                 }
                 a = ctx->attr;
         }
+        write_lock_irqsave(&mft_ni->size_lock, flags);
         mft_ni->allocated_size += nr << vol->cluster_size_bits;
         a->data.non_resident.allocated_size =
                         cpu_to_sle64(mft_ni->allocated_size);
+        write_unlock_irqrestore(&mft_ni->size_lock, flags);
         /* Ensure the changes make it to disk. */
         flush_dcache_mft_record_page(ctx->ntfs_ino);
         mark_mft_record_dirty(ctx->ntfs_ino);
@@ -1892,7 +1920,9 @@ restore_undo_alloc:
                         CASE_SENSITIVE, rl[1].vcn, NULL, 0, ctx)) {
                 ntfs_error(vol->sb, "Failed to find last attribute extent of "
                                 "mft data attribute.%s", es);
+                write_lock_irqsave(&mft_ni->size_lock, flags);
                 mft_ni->allocated_size += nr << vol->cluster_size_bits;
+                write_unlock_irqrestore(&mft_ni->size_lock, flags);
                 ntfs_attr_put_search_ctx(ctx);
                 unmap_mft_record(mft_ni);
                 up_write(&mft_ni->runlist.lock);
@@ -2036,6 +2066,7 @@ static int ntfs_mft_record_layout(const ntfs_volume *vol, const s64 mft_no,
  */
 static int ntfs_mft_record_format(const ntfs_volume *vol, const s64 mft_no)
 {
+        loff_t i_size;
         struct inode *mft_vi = vol->mft_ino;
         struct page *page;
         MFT_RECORD *m;
@@ -2051,10 +2082,11 @@ static int ntfs_mft_record_format(const ntfs_volume *vol, const s64 mft_no)
         index = mft_no << vol->mft_record_size_bits >> PAGE_CACHE_SHIFT;
         ofs = (mft_no << vol->mft_record_size_bits) & ~PAGE_CACHE_MASK;
         /* The maximum valid index into the page cache for $MFT's data. */
-        end_index = mft_vi->i_size >> PAGE_CACHE_SHIFT;
+        i_size = i_size_read(mft_vi);
+        end_index = i_size >> PAGE_CACHE_SHIFT;
         if (unlikely(index >= end_index)) {
                 if (unlikely(index > end_index || ofs + vol->mft_record_size >=
-                                (mft_vi->i_size & ~PAGE_CACHE_MASK))) {
+                                (i_size & ~PAGE_CACHE_MASK))) {
                         ntfs_error(vol->sb, "Tried to format non-existing mft "
                                         "record 0x%llx.", (long long)mft_no);
                         return -ENOENT;
@@ -2188,6 +2220,7 @@ ntfs_inode *ntfs_mft_record_alloc(ntfs_volume *vol, const int mode,
                 ntfs_inode *base_ni, MFT_RECORD **mrec)
 {
         s64 ll, bit, old_data_initialized, old_data_size;
+        unsigned long flags;
         struct inode *vi;
         struct page *page;
         ntfs_inode *mft_ni, *mftbmp_ni, *ni;
@@ -2237,9 +2270,13 @@ ntfs_inode *ntfs_mft_record_alloc(ntfs_volume *vol, const int mode,
          * the first 24 mft records as they are special and whilst they may not
          * be in use, we do not allocate from them.
          */
+        read_lock_irqsave(&mft_ni->size_lock, flags);
         ll = mft_ni->initialized_size >> vol->mft_record_size_bits;
-        if (mftbmp_ni->initialized_size << 3 > ll &&
-                        mftbmp_ni->initialized_size > 3) {
+        read_unlock_irqrestore(&mft_ni->size_lock, flags);
+        read_lock_irqsave(&mftbmp_ni->size_lock, flags);
+        old_data_initialized = mftbmp_ni->initialized_size;
+        read_unlock_irqrestore(&mftbmp_ni->size_lock, flags);
+        if (old_data_initialized << 3 > ll && old_data_initialized > 3) {
                 bit = ll;
                 if (bit < 24)
                         bit = 24;
@@ -2254,15 +2291,18 @@ ntfs_inode *ntfs_mft_record_alloc(ntfs_volume *vol, const int mode,
          * mft record that we can allocate.
          * Note: The smallest mft record we allocate is mft record 24.
          */
-        bit = mftbmp_ni->initialized_size << 3;
+        bit = old_data_initialized << 3;
         if (unlikely(bit >= (1ll << 32)))
                 goto max_err_out;
+        read_lock_irqsave(&mftbmp_ni->size_lock, flags);
+        old_data_size = mftbmp_ni->allocated_size;
         ntfs_debug("Status of mftbmp before extension: allocated_size 0x%llx, "
                         "data_size 0x%llx, initialized_size 0x%llx.",
-                        (long long)mftbmp_ni->allocated_size,
-                        (long long)vol->mftbmp_ino->i_size,
-                        (long long)mftbmp_ni->initialized_size);
-        if (mftbmp_ni->initialized_size + 8 > mftbmp_ni->allocated_size) {
+                        (long long)old_data_size,
+                        (long long)i_size_read(vol->mftbmp_ino),
+                        (long long)old_data_initialized);
+        read_unlock_irqrestore(&mftbmp_ni->size_lock, flags);
+        if (old_data_initialized + 8 > old_data_size) {
                 /* Need to extend bitmap by one more cluster. */
                 ntfs_debug("mftbmp: initialized_size + 8 > allocated_size.");
                 err = ntfs_mft_bitmap_extend_allocation_nolock(vol);
@@ -2270,12 +2310,16 @@ ntfs_inode *ntfs_mft_record_alloc(ntfs_volume *vol, const int mode,
                         up_write(&vol->mftbmp_lock);
                         goto err_out;
                 }
+#ifdef DEBUG
+                read_lock_irqsave(&mftbmp_ni->size_lock, flags);
                 ntfs_debug("Status of mftbmp after allocation extension: "
                                 "allocated_size 0x%llx, data_size 0x%llx, "
                                 "initialized_size 0x%llx.",
                                 (long long)mftbmp_ni->allocated_size,
-                                (long long)vol->mftbmp_ino->i_size,
+                                (long long)i_size_read(vol->mftbmp_ino),
                                 (long long)mftbmp_ni->initialized_size);
+                read_unlock_irqrestore(&mftbmp_ni->size_lock, flags);
+#endif /* DEBUG */
         }
         /*
          * We now have sufficient allocated space, extend the initialized_size
@@ -2287,12 +2331,16 @@ ntfs_inode *ntfs_mft_record_alloc(ntfs_volume *vol, const int mode,
                 up_write(&vol->mftbmp_lock);
                 goto err_out;
         }
+#ifdef DEBUG
+        read_lock_irqsave(&mftbmp_ni->size_lock, flags);
         ntfs_debug("Status of mftbmp after initialized extention: "
                         "allocated_size 0x%llx, data_size 0x%llx, "
                         "initialized_size 0x%llx.",
                         (long long)mftbmp_ni->allocated_size,
-                        (long long)vol->mftbmp_ino->i_size,
+                        (long long)i_size_read(vol->mftbmp_ino),
                         (long long)mftbmp_ni->initialized_size);
+        read_unlock_irqrestore(&mftbmp_ni->size_lock, flags);
+#endif /* DEBUG */
         ntfs_debug("Found free record (#3), bit 0x%llx.", (long long)bit);
 found_free_rec:
         /* @bit is the found free mft record, allocate it in the mft bitmap. */
@@ -2314,7 +2362,10 @@ have_alloc_rec:
          * parallel allocation could allocate the same mft record as this one.
          */
         ll = (bit + 1) << vol->mft_record_size_bits;
-        if (ll <= mft_ni->initialized_size) {
+        read_lock_irqsave(&mft_ni->size_lock, flags);
+        old_data_initialized = mft_ni->initialized_size;
+        read_unlock_irqrestore(&mft_ni->size_lock, flags);
+        if (ll <= old_data_initialized) {
                 ntfs_debug("Allocated mft record already initialized.");
                 goto mft_rec_already_initialized;
         }
@@ -2325,25 +2376,32 @@ have_alloc_rec:
          * actually traversed more than once when a freshly formatted volume is
          * first written to so it optimizes away nicely in the common case.
          */
+        read_lock_irqsave(&mft_ni->size_lock, flags);
+        old_data_size = mft_ni->allocated_size;
         ntfs_debug("Status of mft data before extension: "
                         "allocated_size 0x%llx, data_size 0x%llx, "
                         "initialized_size 0x%llx.",
-                        (long long)mft_ni->allocated_size,
-                        (long long)vol->mft_ino->i_size,
+                        (long long)old_data_size,
+                        (long long)i_size_read(vol->mft_ino),
                         (long long)mft_ni->initialized_size);
-        while (ll > mft_ni->allocated_size) {
+        read_unlock_irqrestore(&mft_ni->size_lock, flags);
+        while (ll > old_data_size) {
                 err = ntfs_mft_data_extend_allocation_nolock(vol);
                 if (unlikely(err)) {
                         ntfs_error(vol->sb, "Failed to extend mft data "
                                         "allocation.");
                         goto undo_mftbmp_alloc_nolock;
                 }
+#ifdef DEBUG
+                read_lock_irqsave(&mft_ni->size_lock, flags);
                 ntfs_debug("Status of mft data after allocation extension: "
                                 "allocated_size 0x%llx, data_size 0x%llx, "
                                 "initialized_size 0x%llx.",
                                 (long long)mft_ni->allocated_size,
-                                (long long)vol->mft_ino->i_size,
+                                (long long)i_size_read(vol->mft_ino),
                                 (long long)mft_ni->initialized_size);
+                read_unlock_irqrestore(&mft_ni->size_lock, flags);
+#endif /* DEBUG */
         }
         /*
          * Extend mft data initialized size (and data size of course) to reach
@@ -2352,6 +2410,7 @@ have_alloc_rec:
          * needed by ntfs_mft_record_format().  We will update the attribute
          * record itself in one fell swoop later on.
          */
+        write_lock_irqsave(&mft_ni->size_lock, flags);
         old_data_initialized = mft_ni->initialized_size;
         old_data_size = vol->mft_ino->i_size;
         while (ll > mft_ni->initialized_size) {
@@ -2360,8 +2419,9 @@ have_alloc_rec:
                 new_initialized_size = mft_ni->initialized_size +
                                 vol->mft_record_size;
                 mft_no = mft_ni->initialized_size >> vol->mft_record_size_bits;
-                if (new_initialized_size > vol->mft_ino->i_size)
-                        vol->mft_ino->i_size = new_initialized_size;
+                if (new_initialized_size > i_size_read(vol->mft_ino))
+                        i_size_write(vol->mft_ino, new_initialized_size);
+                write_unlock_irqrestore(&mft_ni->size_lock, flags);
                 ntfs_debug("Initializing mft record 0x%llx.",
                                 (long long)mft_no);
                 err = ntfs_mft_record_format(vol, mft_no);
@@ -2369,8 +2429,10 @@ have_alloc_rec:
                         ntfs_error(vol->sb, "Failed to format mft record.");
                         goto undo_data_init;
                 }
+                write_lock_irqsave(&mft_ni->size_lock, flags);
                 mft_ni->initialized_size = new_initialized_size;
         }
+        write_unlock_irqrestore(&mft_ni->size_lock, flags);
         record_formatted = TRUE;
         /* Update the mft data attribute record to reflect the new sizes. */
         m = map_mft_record(mft_ni);
@@ -2396,22 +2458,27 @@ have_alloc_rec:
                 goto undo_data_init;
         }
         a = ctx->attr;
+        read_lock_irqsave(&mft_ni->size_lock, flags);
         a->data.non_resident.initialized_size =
                         cpu_to_sle64(mft_ni->initialized_size);
-        a->data.non_resident.data_size = cpu_to_sle64(vol->mft_ino->i_size);
+        a->data.non_resident.data_size =
+                        cpu_to_sle64(i_size_read(vol->mft_ino));
+        read_unlock_irqrestore(&mft_ni->size_lock, flags);
         /* Ensure the changes make it to disk. */
         flush_dcache_mft_record_page(ctx->ntfs_ino);
         mark_mft_record_dirty(ctx->ntfs_ino);
         ntfs_attr_put_search_ctx(ctx);
         unmap_mft_record(mft_ni);
+        read_lock_irqsave(&mft_ni->size_lock, flags);
         ntfs_debug("Status of mft data after mft record initialization: "
                         "allocated_size 0x%llx, data_size 0x%llx, "
                         "initialized_size 0x%llx.",
                         (long long)mft_ni->allocated_size,
-                        (long long)vol->mft_ino->i_size,
+                        (long long)i_size_read(vol->mft_ino),
                         (long long)mft_ni->initialized_size);
-        BUG_ON(vol->mft_ino->i_size > mft_ni->allocated_size);
-        BUG_ON(mft_ni->initialized_size > vol->mft_ino->i_size);
+        BUG_ON(i_size_read(vol->mft_ino) > mft_ni->allocated_size);
+        BUG_ON(mft_ni->initialized_size > i_size_read(vol->mft_ino));
+        read_unlock_irqrestore(&mft_ni->size_lock, flags);
 mft_rec_already_initialized:
         /*
          * We can finally drop the mft bitmap lock as the mft data attribute
@@ -2652,8 +2719,10 @@ mft_rec_already_initialized:
         *mrec = m;
         return ni;
 undo_data_init:
+        write_lock_irqsave(&mft_ni->size_lock, flags);
         mft_ni->initialized_size = old_data_initialized;
-        vol->mft_ino->i_size = old_data_size;
+        i_size_write(vol->mft_ino, old_data_size);
+        write_unlock_irqrestore(&mft_ni->size_lock, flags);
         goto undo_mftbmp_alloc_nolock;
 undo_mftbmp_alloc:
         down_write(&vol->mftbmp_lock);