NTFS: - Split ntfs_map_runlist() into ntfs_map_runlist() and a non-locking

	helper ntfs_map_runlist_nolock() which is used by ntfs_map_runlist().
	This allows us to map runlist fragments with the runlist lock already
	held without having to drop and reacquire it around the call.  Adapt
	all callers.
      - Change ntfs_find_vcn() to ntfs_find_vcn_nolock() which takes a locked
	runlist.  This allows us to find runlist elements with the runlist
	lock already held without having to drop and reacquire it around the
	call.  Adapt all callers.

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

6 files changed, 119 insertions, 113 deletions

diff --git a/fs/ntfs/ChangeLog b/fs/ntfs/ChangeLog
index b40c334e616f..9d42393c16c0 100644
--- a/fs/ntfs/ChangeLog
+++ b/fs/ntfs/ChangeLog
@@ -63,6 +63,15 @@ ToDo/Notes:
         - Fix a bug in fs/ntfs/runlist.c::ntfs_mapping_pairs_decompress() in
           the creation of the unmapped runlist element for the base attribute
           extent.
+        - Split ntfs_map_runlist() into ntfs_map_runlist() and a non-locking
+          helper ntfs_map_runlist_nolock() which is used by ntfs_map_runlist().
+          This allows us to map runlist fragments with the runlist lock already
+          held without having to drop and reacquire it around the call.  Adapt
+          all callers.
+        - Change ntfs_find_vcn() to ntfs_find_vcn_nolock() which takes a locked
+          runlist.  This allows us to find runlist elements with the runlist
+          lock already held without having to drop and reacquire it around the
+          call.  Adapt all callers.
 
 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 812d53e93354..2b4b8b9e8796 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
@@ -135,7 +135,7 @@ 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);
@@ -347,11 +347,11 @@ 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;
 
@@ -389,9 +389,9 @@ static int ntfs_readpage(struct file *file, struct page *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.
          */
-        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);
@@ -418,9 +418,10 @@ 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 +
@@ -1247,20 +1248,6 @@ static int ntfs_writepage(struct page *page, struct writeback_control *wbc)
         int err;
 
         BUG_ON(!PageLocked(page));
-        /*
-         * If a previous ntfs_truncate() failed, repeat it and abort if it
-         * fails again.
-         */
-        if (unlikely(NInoTruncateFailed(ni))) {
-                down_write(&vi->i_alloc_sem);
-                err = ntfs_truncate(vi);
-                up_write(&vi->i_alloc_sem);
-                if (err || NInoTruncateFailed(ni)) {
-                        if (!err)
-                                err = -EIO;
-                        goto err_out;
-                }
-        }
         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) >>
@@ -1490,13 +1477,12 @@ static int ntfs_prepare_nonresident_write(struct page *page,
 
         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);
diff --git a/fs/ntfs/attrib.c b/fs/ntfs/attrib.c
index 7d668466dcd7..7a16f7ca76d8 100644
--- a/fs/ntfs/attrib.c
+++ b/fs/ntfs/attrib.c
@@ -1,7 +1,7 @@
 /**
  * attrib.c - NTFS attribute operations.  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
@@ -30,7 +30,7 @@
 #include "types.h"
 
 /**
- * ntfs_map_runlist - map (a part of) a runlist of an ntfs inode
+ * ntfs_map_runlist_nolock - map (a part of) a runlist of an ntfs inode
  * @ni:         ntfs inode for which to map (part of) a runlist
  * @vcn:        map runlist part containing this vcn
  *
@@ -38,24 +38,23 @@
  *
  * Return 0 on success and -errno on error.
  *
- * Locking: - The runlist must be unlocked on entry and is unlocked on return.
- *          - This function takes the lock for writing and modifies the runlist.
+ * Locking: - The runlist must be locked for writing.
+ *          - This function modifies the runlist.
  */
-int ntfs_map_runlist(ntfs_inode *ni, VCN vcn)
+int ntfs_map_runlist_nolock(ntfs_inode *ni, VCN vcn)
 {
         ntfs_inode *base_ni;
-        ntfs_attr_search_ctx *ctx;
         MFT_RECORD *mrec;
+        ntfs_attr_search_ctx *ctx;
+        runlist_element *rl;
         int err = 0;
 
         ntfs_debug("Mapping runlist part containing vcn 0x%llx.",
                         (unsigned long long)vcn);
-
         if (!NInoAttr(ni))
                 base_ni = ni;
         else
                 base_ni = ni->ext.base_ntfs_ino;
-
         mrec = map_mft_record(base_ni);
         if (IS_ERR(mrec))
                 return PTR_ERR(mrec);
@@ -66,15 +65,7 @@ int ntfs_map_runlist(ntfs_inode *ni, VCN vcn)
         }
         err = ntfs_attr_lookup(ni->type, ni->name, ni->name_len,
                         CASE_SENSITIVE, vcn, NULL, 0, ctx);
-        if (unlikely(err))
-                goto put_err_out;
-
-        down_write(&ni->runlist.lock);
-        /* Make sure someone else didn't do the work while we were sleeping. */
-        if (likely(ntfs_rl_vcn_to_lcn(ni->runlist.rl, vcn) <=
-                        LCN_RL_NOT_MAPPED)) {
-                runlist_element *rl;
-
+        if (likely(!err)) {
                 rl = ntfs_mapping_pairs_decompress(ni->vol, ctx->attr,
                                 ni->runlist.rl);
                 if (IS_ERR(rl))
@@ -82,9 +73,6 @@ int ntfs_map_runlist(ntfs_inode *ni, VCN vcn)
                 else
                         ni->runlist.rl = rl;
         }
-        up_write(&ni->runlist.lock);
-
-put_err_out:
         ntfs_attr_put_search_ctx(ctx);
 err_out:
         unmap_mft_record(base_ni);
@@ -92,17 +80,45 @@ err_out:
 }
 
 /**
- * ntfs_find_vcn - find a vcn in the runlist described by an ntfs inode
- * @ni:         ntfs inode describing the runlist to search
- * @vcn:        vcn to find
- * @need_write: if false, lock for reading and if true, lock for writing
+ * ntfs_map_runlist - map (a part of) a runlist of an ntfs inode
+ * @ni:         ntfs inode for which to map (part of) a runlist
+ * @vcn:        map runlist part containing this vcn
+ *
+ * Map the part of a runlist containing the @vcn of the ntfs inode @ni.
+ *
+ * Return 0 on success and -errno on error.
+ *
+ * Locking: - The runlist must be unlocked on entry and is unlocked on return.
+ *          - This function takes the runlist lock for writing and modifies the
+ *            runlist.
+ */
+int ntfs_map_runlist(ntfs_inode *ni, VCN vcn)
+{
+        int err = 0;
+
+        down_write(&ni->runlist.lock);
+        /* Make sure someone else didn't do the work while we were sleeping. */
+        if (likely(ntfs_rl_vcn_to_lcn(ni->runlist.rl, vcn) <=
+                        LCN_RL_NOT_MAPPED))
+                err = ntfs_map_runlist_nolock(ni, vcn);
+        up_write(&ni->runlist.lock);
+        return err;
+}
+
+/**
+ * ntfs_find_vcn_nolock - find a vcn in the runlist described by an ntfs inode
+ * @ni:                 ntfs inode describing the runlist to search
+ * @vcn:                vcn to find
+ * @write_locked:       true if the runlist is locked for writing
  *
  * Find the virtual cluster number @vcn in the runlist described by the ntfs
  * inode @ni and return the address of the runlist element containing the @vcn.
- * The runlist is left locked and the caller has to unlock it.  If @need_write
- * is true, the runlist is locked for writing and if @need_write is false, the
- * runlist is locked for reading.  In the error case, the runlist is not left
- * locked.
+ * The runlist is left locked and the caller has to unlock it.  In the error
+ * case, the runlist is left in the same locking state as on entry.
+ *
+ * Note if @write_locked is FALSE the lock may be dropped inside the function
+ * so you cannot rely on the runlist still being the same when this function
+ * returns.
  *
  * Note you need to distinguish between the lcn of the returned runlist element
  * being >= 0 and LCN_HOLE.  In the later case you have to return zeroes on
@@ -124,28 +140,24 @@ err_out:
  *            true, it is locked for writing.  Otherwise is is locked for
  *            reading.
  */
-runlist_element *ntfs_find_vcn(ntfs_inode *ni, const VCN vcn,
-                const BOOL need_write)
+runlist_element *ntfs_find_vcn_nolock(ntfs_inode *ni, const VCN vcn,
+                const BOOL write_locked)
 {
         runlist_element *rl;
         int err = 0;
         BOOL is_retry = FALSE;
 
-        ntfs_debug("Entering for i_ino 0x%lx, vcn 0x%llx, lock for %sing.",
+        ntfs_debug("Entering for i_ino 0x%lx, vcn 0x%llx, %s_locked.",
                         ni->mft_no, (unsigned long long)vcn,
-                        !need_write ? "read" : "writ");
+                        write_locked ? "write" : "read");
         BUG_ON(!ni);
         BUG_ON(!NInoNonResident(ni));
         BUG_ON(vcn < 0);
-lock_retry_remap:
-        if (!need_write)
-                down_read(&ni->runlist.lock);
-        else
-                down_write(&ni->runlist.lock);
+retry_remap:
         rl = ni->runlist.rl;
         if (likely(rl && vcn >= rl[0].vcn)) {
                 while (likely(rl->length)) {
-                        if (likely(vcn < rl[1].vcn)) {
+                        if (unlikely(vcn < rl[1].vcn)) {
                                 if (likely(rl->lcn >= LCN_HOLE)) {
                                         ntfs_debug("Done.");
                                         return rl;
@@ -161,19 +173,23 @@ lock_retry_remap:
                                 err = -EIO;
                 }
         }
-        if (!need_write)
-                up_read(&ni->runlist.lock);
-        else
-                up_write(&ni->runlist.lock);
         if (!err && !is_retry) {
                 /*
                  * The @vcn is in an unmapped region, map the runlist and
                  * retry.
                  */
-                err = ntfs_map_runlist(ni, vcn);
+                if (!write_locked) {
+                        up_read(&ni->runlist.lock);
+                        down_write(&ni->runlist.lock);
+                }
+                err = ntfs_map_runlist_nolock(ni, vcn);
+                if (!write_locked) {
+                        up_write(&ni->runlist.lock);
+                        down_read(&ni->runlist.lock);
+                }
                 if (likely(!err)) {
                         is_retry = TRUE;
-                        goto lock_retry_remap;
+                        goto retry_remap;
                 }
                 /*
                  * -EINVAL and -ENOENT coming from a failed mapping attempt are
@@ -184,7 +200,8 @@ lock_retry_remap:
                         err = -EIO;
         } else if (!err)
                 err = -EIO;
-        ntfs_error(ni->vol->sb, "Failed with error code %i.", err);
+        if (err != -ENOENT)
+                ntfs_error(ni->vol->sb, "Failed with error code %i.", err);
         return ERR_PTR(err);
 }
 
diff --git a/fs/ntfs/attrib.h b/fs/ntfs/attrib.h
index e0c2c6c81bc0..3eb451657025 100644
--- a/fs/ntfs/attrib.h
+++ b/fs/ntfs/attrib.h
@@ -60,10 +60,11 @@ typedef struct {
         ATTR_RECORD *base_attr;
 } ntfs_attr_search_ctx;
 
+extern int ntfs_map_runlist_nolock(ntfs_inode *ni, VCN vcn);
 extern int ntfs_map_runlist(ntfs_inode *ni, VCN vcn);
 
-extern runlist_element *ntfs_find_vcn(ntfs_inode *ni, const VCN vcn,
-                const BOOL need_write);
+extern runlist_element *ntfs_find_vcn_nolock(ntfs_inode *ni, const VCN vcn,
+                const BOOL write_locked);
 
 int ntfs_attr_lookup(const ATTR_TYPE type, const ntfschar *name,
                 const u32 name_len, const IGNORE_CASE_BOOL ic,
diff --git a/fs/ntfs/lcnalloc.c b/fs/ntfs/lcnalloc.c
index 5346596fa871..8db4492b139c 100644
--- a/fs/ntfs/lcnalloc.c
+++ b/fs/ntfs/lcnalloc.c
@@ -849,7 +849,8 @@ s64 __ntfs_cluster_free(struct inode *vi, const VCN start_vcn, s64 count,
         total_freed = real_freed = 0;
 
         /* This returns with ni->runlist locked for reading on success. */
-        rl = ntfs_find_vcn(ni, start_vcn, FALSE);
+        down_read(&ni->runlist.lock);
+        rl = ntfs_find_vcn_nolock(ni, start_vcn, FALSE);
         if (IS_ERR(rl)) {
                 if (!is_rollback)
                         ntfs_error(vol->sb, "Failed to find first runlist "
@@ -863,7 +864,7 @@ s64 __ntfs_cluster_free(struct inode *vi, const VCN start_vcn, s64 count,
                         ntfs_error(vol->sb, "First runlist element has "
                                         "invalid lcn, aborting.");
                 err = -EIO;
-                goto unl_err_out;
+                goto err_out;
         }
         /* Find the starting cluster inside the run that needs freeing. */
         delta = start_vcn - rl->vcn;
@@ -881,7 +882,7 @@ s64 __ntfs_cluster_free(struct inode *vi, const VCN start_vcn, s64 count,
                         if (!is_rollback)
                                 ntfs_error(vol->sb, "Failed to clear first run "
                                                 "(error %i), aborting.", err);
-                        goto unl_err_out;
+                        goto err_out;
                 }
                 /* We have freed @to_free real clusters. */
                 real_freed = to_free;
@@ -901,30 +902,15 @@ s64 __ntfs_cluster_free(struct inode *vi, const VCN start_vcn, s64 count,
                 if (unlikely(rl->lcn < LCN_HOLE)) {
                         VCN vcn;
 
-                        /*
-                         * Attempt to map runlist, dropping runlist lock for
-                         * the duration.
-                         */
+                        /* Attempt to map runlist. */
                         vcn = rl->vcn;
-                        up_read(&ni->runlist.lock);
-                        err = ntfs_map_runlist(ni, vcn);
-                        if (err) {
-                                if (!is_rollback)
-                                        ntfs_error(vol->sb, "Failed to map "
-                                                        "runlist fragment.");
-                                if (err == -EINVAL || err == -ENOENT)
-                                        err = -EIO;
-                                goto err_out;
-                        }
-                        /*
-                         * This returns with ni->runlist locked for reading on
-                         * success.
-                         */
-                        rl = ntfs_find_vcn(ni, vcn, FALSE);
+                        rl = ntfs_find_vcn_nolock(ni, vcn, FALSE);
                         if (IS_ERR(rl)) {
                                 err = PTR_ERR(rl);
                                 if (!is_rollback)
-                                        ntfs_error(vol->sb, "Failed to find "
+                                        ntfs_error(vol->sb, "Failed to map "
+                                                        "runlist fragment or "
+                                                        "failed to find "
                                                         "subsequent runlist "
                                                         "element.");
                                 goto err_out;
@@ -937,7 +923,7 @@ s64 __ntfs_cluster_free(struct inode *vi, const VCN start_vcn, s64 count,
                                                         (unsigned long long)
                                                         rl->lcn);
                                 err = -EIO;
-                                goto unl_err_out;
+                                goto err_out;
                         }
                 }
                 /* The number of clusters in this run that need freeing. */
@@ -953,7 +939,7 @@ s64 __ntfs_cluster_free(struct inode *vi, const VCN start_vcn, s64 count,
                                 if (!is_rollback)
                                         ntfs_error(vol->sb, "Failed to clear "
                                                         "subsequent run.");
-                                goto unl_err_out;
+                                goto err_out;
                         }
                         /* We have freed @to_free real clusters. */
                         real_freed += to_free;
@@ -974,9 +960,8 @@ s64 __ntfs_cluster_free(struct inode *vi, const VCN start_vcn, s64 count,
         /* We are done.  Return the number of actually freed clusters. */
         ntfs_debug("Done.");
         return real_freed;
-unl_err_out:
-        up_read(&ni->runlist.lock);
 err_out:
+        up_read(&ni->runlist.lock);
         if (is_rollback)
                 return err;
         /* If no real clusters were freed, no need to rollback. */
diff --git a/fs/ntfs/mft.c b/fs/ntfs/mft.c
index 4e0bf39426cf..0975d738834c 100644
--- a/fs/ntfs/mft.c
+++ b/fs/ntfs/mft.c
@@ -1,7 +1,7 @@
 /**
  * mft.c - NTFS kernel mft record operations. 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
@@ -287,7 +287,7 @@ MFT_RECORD *map_extent_mft_record(ntfs_inode *base_ni, MFT_REF mref,
                         }
                         unmap_mft_record(ni);
                         ntfs_error(base_ni->vol->sb, "Found stale extent mft "
-                                        "reference! Corrupt file system. "
+                                        "reference! Corrupt filesystem. "
                                         "Run chkdsk.");
                         return ERR_PTR(-EIO);
                 }
@@ -318,7 +318,7 @@ map_err_out:
         /* Verify the sequence number if it is present. */
         if (seq_no && (le16_to_cpu(m->sequence_number) != seq_no)) {
                 ntfs_error(base_ni->vol->sb, "Found stale extent mft "
-                                "reference! Corrupt file system. Run chkdsk.");
+                                "reference! Corrupt filesystem. Run chkdsk.");
                 destroy_ni = TRUE;
                 m = ERR_PTR(-EIO);
                 goto unm_err_out;
@@ -1292,19 +1292,20 @@ static int ntfs_mft_bitmap_extend_allocation_nolock(ntfs_volume *vol)
         /*
          * Determine the last lcn of the mft bitmap.  The allocated size of the
          * mft bitmap cannot be zero so we are ok to do this.
-         * ntfs_find_vcn() returns the runlist locked on success.
          */
+        down_write(&mftbmp_ni->runlist.lock);
         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);
+        rl = ntfs_find_vcn_nolock(mftbmp_ni,
+                        (ll - 1) >> vol->cluster_size_bits, TRUE);
         if (unlikely(IS_ERR(rl) || !rl->length || rl->lcn < 0)) {
+                up_write(&mftbmp_ni->runlist.lock);
                 ntfs_error(vol->sb, "Failed to determine last allocated "
                                 "cluster of mft bitmap attribute.");
-                if (!IS_ERR(rl)) {
-                        up_write(&mftbmp_ni->runlist.lock);
+                if (!IS_ERR(rl))
                         ret = -EIO;
-                } else
+                else
                         ret = PTR_ERR(rl);
                 return ret;
         }
@@ -1428,6 +1429,8 @@ static int ntfs_mft_bitmap_extend_allocation_nolock(ntfs_volume *vol)
                 // TODO: Deal with this by moving this extent to a new mft
                 // record or by starting a new extent in a new mft record or by
                 // moving other attributes out of this mft record.
+                // Note: It will need to be a special mft record and if none of
+                // those are available it gets rather complicated...
                 ntfs_error(vol->sb, "Not enough space in this mft record to "
                                 "accomodate extended mft bitmap attribute "
                                 "extent.  Cannot handle this yet.");
@@ -1719,19 +1722,20 @@ static int ntfs_mft_data_extend_allocation_nolock(ntfs_volume *vol)
          * Determine the preferred allocation location, i.e. the last lcn of
          * the mft data attribute.  The allocated size of the mft data
          * attribute cannot be zero so we are ok to do this.
-         * ntfs_find_vcn() returns the runlist locked on success.
          */
+        down_write(&mft_ni->runlist.lock);
         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);
+        rl = ntfs_find_vcn_nolock(mft_ni, (ll - 1) >> vol->cluster_size_bits,
+                        TRUE);
         if (unlikely(IS_ERR(rl) || !rl->length || rl->lcn < 0)) {
+                up_write(&mft_ni->runlist.lock);
                 ntfs_error(vol->sb, "Failed to determine last allocated "
                                 "cluster of mft data attribute.");
-                if (!IS_ERR(rl)) {
-                        up_write(&mft_ni->runlist.lock);
+                if (!IS_ERR(rl))
                         ret = -EIO;
-                } else
+                else
                         ret = PTR_ERR(rl);
                 return ret;
         }
@@ -1858,7 +1862,11 @@ static int ntfs_mft_data_extend_allocation_nolock(ntfs_volume *vol)
                 // moving other attributes out of this mft record.
                 // Note: Use the special reserved mft records and ensure that
                 // this extent is not required to find the mft record in
-                // question.
+                // question.  If no free special records left we would need to
+                // move an existing record away, insert ours in its place, and
+                // then place the moved record into the newly allocated space
+                // and we would then need to update all references to this mft
+                // record appropriately.  This is rather complicated...
                 ntfs_error(vol->sb, "Not enough space in this mft record to "
                                 "accomodate extended mft data attribute "
                                 "extent.  Cannot handle this yet.");
@@ -2021,7 +2029,7 @@ static int ntfs_mft_record_layout(const ntfs_volume *vol, const s64 mft_no,
                                 "reports this as corruption, please email "
                                 "linux-ntfs-dev@lists.sourceforge.net stating "
                                 "that you saw this message and that the "
-                                "modified file system created was corrupt.  "
+                                "modified filesystem created was corrupt.  "
                                 "Thank you.");
         }
         /* Set the update sequence number to 1. */