Merge branch 'master'

1 files changed, 902 insertions, 81 deletions

diff --git a/fs/ntfs/attrib.c b/fs/ntfs/attrib.c
index 3f9a4ff42ee..eda056bac25 100644
--- a/fs/ntfs/attrib.c
+++ b/fs/ntfs/attrib.c
@@ -21,7 +21,9 @@
  */
 
 #include <linux/buffer_head.h>
+#include <linux/sched.h>
 #include <linux/swap.h>
+#include <linux/writeback.h>
 
 #include "attrib.h"
 #include "debug.h"
@@ -36,9 +38,27 @@
  * 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
+ * @ctx:	active attribute search context if present or NULL if not
  *
  * Map the part of a runlist containing the @vcn of the ntfs inode @ni.
  *
+ * If @ctx is specified, it is an active search context of @ni and its base mft
+ * record.  This is needed when ntfs_map_runlist_nolock() encounters unmapped
+ * runlist fragments and allows their mapping.  If you do not have the mft
+ * record mapped, you can specify @ctx as NULL and ntfs_map_runlist_nolock()
+ * will perform the necessary mapping and unmapping.
+ *
+ * Note, ntfs_map_runlist_nolock() saves the state of @ctx on entry and
+ * restores it before returning.  Thus, @ctx will be left pointing to the same
+ * attribute on return as on entry.  However, the actual pointers in @ctx may
+ * point to different memory locations on return, so you must remember to reset
+ * any cached pointers from the @ctx, i.e. after the call to
+ * ntfs_map_runlist_nolock(), you will probably want to do:
+ *	m = ctx->mrec;
+ *	a = ctx->attr;
+ * Assuming you cache ctx->attr in a variable @a of type ATTR_RECORD * and that
+ * you cache ctx->mrec in a variable @m of type MFT_RECORD *.
+ *
  * Return 0 on success and -errno on error.  There is one special error code
  * which is not an error as such.  This is -ENOENT.  It means that @vcn is out
  * of bounds of the runlist.
@@ -46,19 +66,32 @@
  * Note the runlist can be NULL after this function returns if @vcn is zero and
  * the attribute has zero allocated size, i.e. there simply is no runlist.
  *
- * Locking: - The runlist must be locked for writing.
- *	    - This function modifies the runlist.
+ * WARNING: If @ctx is supplied, regardless of whether success or failure is
+ *	    returned, you need to check IS_ERR(@ctx->mrec) and if TRUE the @ctx
+ *	    is no longer valid, i.e. you need to either call
+ *	    ntfs_attr_reinit_search_ctx() or ntfs_attr_put_search_ctx() on it.
+ *	    In that case PTR_ERR(@ctx->mrec) will give you the error code for
+ *	    why the mapping of the old inode failed.
+ *
+ * Locking: - The runlist described by @ni must be locked for writing on entry
+ *	      and is locked on return.  Note the runlist will be modified.
+ *	    - If @ctx is NULL, the base mft record of @ni must not be mapped on
+ *	      entry and it will be left unmapped on return.
+ *	    - If @ctx is not NULL, the base mft record must be mapped on entry
+ *	      and it will be left mapped on return.
  */
-int ntfs_map_runlist_nolock(ntfs_inode *ni, VCN vcn)
+int ntfs_map_runlist_nolock(ntfs_inode *ni, VCN vcn, ntfs_attr_search_ctx *ctx)
 {
 	VCN end_vcn;
+	unsigned long flags;
 	ntfs_inode *base_ni;
 	MFT_RECORD *m;
 	ATTR_RECORD *a;
-	ntfs_attr_search_ctx *ctx;
 	runlist_element *rl;
-	unsigned long flags;
+	struct page *put_this_page = NULL;
 	int err = 0;
+	BOOL ctx_is_temporary, ctx_needs_reset;
+	ntfs_attr_search_ctx old_ctx = { NULL, };
 
 	ntfs_debug("Mapping runlist part containing vcn 0x%llx.",
 			(unsigned long long)vcn);
@@ -66,20 +99,77 @@ int ntfs_map_runlist_nolock(ntfs_inode *ni, VCN vcn)
 		base_ni = ni;
 	else
 		base_ni = ni->ext.base_ntfs_ino;
-	m = map_mft_record(base_ni);
-	if (IS_ERR(m))
-		return PTR_ERR(m);
-	ctx = ntfs_attr_get_search_ctx(base_ni, m);
-	if (unlikely(!ctx)) {
-		err = -ENOMEM;
-		goto err_out;
+	if (!ctx) {
+		ctx_is_temporary = ctx_needs_reset = TRUE;
+		m = map_mft_record(base_ni);
+		if (IS_ERR(m))
+			return PTR_ERR(m);
+		ctx = ntfs_attr_get_search_ctx(base_ni, m);
+		if (unlikely(!ctx)) {
+			err = -ENOMEM;
+			goto err_out;
+		}
+	} else {
+		VCN allocated_size_vcn;
+
+		BUG_ON(IS_ERR(ctx->mrec));
+		a = ctx->attr;
+		BUG_ON(!a->non_resident);
+		ctx_is_temporary = FALSE;
+		end_vcn = sle64_to_cpu(a->data.non_resident.highest_vcn);
+		read_lock_irqsave(&ni->size_lock, flags);
+		allocated_size_vcn = ni->allocated_size >>
+				ni->vol->cluster_size_bits;
+		read_unlock_irqrestore(&ni->size_lock, flags);
+		if (!a->data.non_resident.lowest_vcn && end_vcn <= 0)
+			end_vcn = allocated_size_vcn - 1;
+		/*
+		 * If we already have the attribute extent containing @vcn in
+		 * @ctx, no need to look it up again.  We slightly cheat in
+		 * that if vcn exceeds the allocated size, we will refuse to
+		 * map the runlist below, so there is definitely no need to get
+		 * the right attribute extent.
+		 */
+		if (vcn >= allocated_size_vcn || (a->type == ni->type &&
+				a->name_length == ni->name_len &&
+				!memcmp((u8*)a + le16_to_cpu(a->name_offset),
+				ni->name, ni->name_len) &&
+				sle64_to_cpu(a->data.non_resident.lowest_vcn)
+				<= vcn && end_vcn >= vcn))
+			ctx_needs_reset = FALSE;
+		else {
+			/* Save the old search context. */
+			old_ctx = *ctx;
+			/*
+			 * If the currently mapped (extent) inode is not the
+			 * base inode we will unmap it when we reinitialize the
+			 * search context which means we need to get a
+			 * reference to the page containing the mapped mft
+			 * record so we do not accidentally drop changes to the
+			 * mft record when it has not been marked dirty yet.
+			 */
+			if (old_ctx.base_ntfs_ino && old_ctx.ntfs_ino !=
+					old_ctx.base_ntfs_ino) {
+				put_this_page = old_ctx.ntfs_ino->page;
+				page_cache_get(put_this_page);
+			}
+			/*
+			 * Reinitialize the search context so we can lookup the
+			 * needed attribute extent.
+			 */
+			ntfs_attr_reinit_search_ctx(ctx);
+			ctx_needs_reset = TRUE;
+		}
 	}
-	err = ntfs_attr_lookup(ni->type, ni->name, ni->name_len,
-			CASE_SENSITIVE, vcn, NULL, 0, ctx);
-	if (unlikely(err)) {
-		if (err == -ENOENT)
-			err = -EIO;
-		goto err_out;
+	if (ctx_needs_reset) {
+		err = ntfs_attr_lookup(ni->type, ni->name, ni->name_len,
+				CASE_SENSITIVE, vcn, NULL, 0, ctx);
+		if (unlikely(err)) {
+			if (err == -ENOENT)
+				err = -EIO;
+			goto err_out;
+		}
+		BUG_ON(!ctx->attr->non_resident);
 	}
 	a = ctx->attr;
 	/*
@@ -89,11 +179,9 @@ int ntfs_map_runlist_nolock(ntfs_inode *ni, VCN vcn)
 	 * ntfs_mapping_pairs_decompress() fails.
 	 */
 	end_vcn = sle64_to_cpu(a->data.non_resident.highest_vcn) + 1;
-	if (unlikely(!a->data.non_resident.lowest_vcn && end_vcn <= 1)) {
-		read_lock_irqsave(&ni->size_lock, flags);
-		end_vcn = ni->allocated_size >> ni->vol->cluster_size_bits;
-		read_unlock_irqrestore(&ni->size_lock, flags);
-	}
+	if (!a->data.non_resident.lowest_vcn && end_vcn == 1)
+		end_vcn = sle64_to_cpu(a->data.non_resident.allocated_size) >>
+				ni->vol->cluster_size_bits;
 	if (unlikely(vcn >= end_vcn)) {
 		err = -ENOENT;
 		goto err_out;
@@ -104,9 +192,93 @@ int ntfs_map_runlist_nolock(ntfs_inode *ni, VCN vcn)
 	else
 		ni->runlist.rl = rl;
 err_out:
-	if (likely(ctx))
-		ntfs_attr_put_search_ctx(ctx);
-	unmap_mft_record(base_ni);
+	if (ctx_is_temporary) {
+		if (likely(ctx))
+			ntfs_attr_put_search_ctx(ctx);
+		unmap_mft_record(base_ni);
+	} else if (ctx_needs_reset) {
+		/*
+		 * If there is no attribute list, restoring the search context
+		 * is acomplished simply by copying the saved context back over
+		 * the caller supplied context.  If there is an attribute list,
+		 * things are more complicated as we need to deal with mapping
+		 * of mft records and resulting potential changes in pointers.
+		 */
+		if (NInoAttrList(base_ni)) {
+			/*
+			 * If the currently mapped (extent) inode is not the
+			 * one we had before, we need to unmap it and map the
+			 * old one.
+			 */
+			if (ctx->ntfs_ino != old_ctx.ntfs_ino) {
+				/*
+				 * If the currently mapped inode is not the
+				 * base inode, unmap it.
+				 */
+				if (ctx->base_ntfs_ino && ctx->ntfs_ino !=
+						ctx->base_ntfs_ino) {
+					unmap_extent_mft_record(ctx->ntfs_ino);
+					ctx->mrec = ctx->base_mrec;
+					BUG_ON(!ctx->mrec);
+				}
+				/*
+				 * If the old mapped inode is not the base
+				 * inode, map it.
+				 */
+				if (old_ctx.base_ntfs_ino &&
+						old_ctx.ntfs_ino !=
+						old_ctx.base_ntfs_ino) {
+retry_map:
+					ctx->mrec = map_mft_record(
+							old_ctx.ntfs_ino);
+					/*
+					 * Something bad has happened.  If out
+					 * of memory retry till it succeeds.
+					 * Any other errors are fatal and we
+					 * return the error code in ctx->mrec.
+					 * Let the caller deal with it...  We
+					 * just need to fudge things so the
+					 * caller can reinit and/or put the
+					 * search context safely.
+					 */
+					if (IS_ERR(ctx->mrec)) {
+						if (PTR_ERR(ctx->mrec) ==
+								-ENOMEM) {
+							schedule();
+							goto retry_map;
+						} else
+							old_ctx.ntfs_ino =
+								old_ctx.
+								base_ntfs_ino;
+					}
+				}
+			}
+			/* Update the changed pointers in the saved context. */
+			if (ctx->mrec != old_ctx.mrec) {
+				if (!IS_ERR(ctx->mrec))
+					old_ctx.attr = (ATTR_RECORD*)(
+							(u8*)ctx->mrec +
+							((u8*)old_ctx.attr -
+							(u8*)old_ctx.mrec));
+				old_ctx.mrec = ctx->mrec;
+			}
+		}
+		/* Restore the search context to the saved one. */
+		*ctx = old_ctx;
+		/*
+		 * We drop the reference on the page we took earlier.  In the
+		 * case that IS_ERR(ctx->mrec) is true this means we might lose
+		 * some changes to the mft record that had been made between
+		 * the last time it was marked dirty/written out and now.  This
+		 * at this stage is not a problem as the mapping error is fatal
+		 * enough that the mft record cannot be written out anyway and
+		 * the caller is very likely to shutdown the whole inode
+		 * immediately and mark the volume dirty for chkdsk to pick up
+		 * the pieces anyway.
+		 */
+		if (put_this_page)
+			page_cache_release(put_this_page);
+	}
 	return err;
 }
 
@@ -122,8 +294,8 @@ err_out:
  * of bounds of the runlist.
  *
  * 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.
+ *	    - This function takes the runlist lock for writing and may modify
+ *	      the runlist.
  */
 int ntfs_map_runlist(ntfs_inode *ni, VCN vcn)
 {
@@ -133,7 +305,7 @@ int ntfs_map_runlist(ntfs_inode *ni, VCN vcn)
 	/* 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);
+		err = ntfs_map_runlist_nolock(ni, vcn, NULL);
 	up_write(&ni->runlist.lock);
 	return err;
 }
@@ -212,7 +384,7 @@ retry_remap:
 				goto retry_remap;
 			}
 		}
-		err = ntfs_map_runlist_nolock(ni, vcn);
+		err = ntfs_map_runlist_nolock(ni, vcn, NULL);
 		if (!write_locked) {
 			up_write(&ni->runlist.lock);
 			down_read(&ni->runlist.lock);
@@ -236,9 +408,9 @@ retry_remap:
 
 /**
  * ntfs_attr_find_vcn_nolock - find a vcn in the runlist of 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
+ * @ni:		ntfs inode describing the runlist to search
+ * @vcn:	vcn to find
+ * @ctx:	active attribute search context if present or NULL if not
  *
  * 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.
@@ -246,9 +418,22 @@ retry_remap:
  * If the @vcn is not mapped yet, the attempt is made to map the attribute
  * extent containing the @vcn and the vcn to lcn conversion is retried.
  *
- * If @write_locked is true the caller has locked the runlist for writing and
- * if false for reading.
- *
+ * If @ctx is specified, it is an active search context of @ni and its base mft
+ * record.  This is needed when ntfs_attr_find_vcn_nolock() encounters unmapped
+ * runlist fragments and allows their mapping.  If you do not have the mft
+ * record mapped, you can specify @ctx as NULL and ntfs_attr_find_vcn_nolock()
+ * will perform the necessary mapping and unmapping.
+ *
+ * Note, ntfs_attr_find_vcn_nolock() saves the state of @ctx on entry and
+ * restores it before returning.  Thus, @ctx will be left pointing to the same
+ * attribute on return as on entry.  However, the actual pointers in @ctx may
+ * point to different memory locations on return, so you must remember to reset
+ * any cached pointers from the @ctx, i.e. after the call to
+ * ntfs_attr_find_vcn_nolock(), you will probably want to do:
+ *	m = ctx->mrec;
+ *	a = ctx->attr;
+ * Assuming you cache ctx->attr in a variable @a of type ATTR_RECORD * and that
+ * you cache ctx->mrec in a variable @m of type MFT_RECORD *.
  * 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
  * read and allocate clusters on write.
@@ -263,22 +448,31 @@ retry_remap:
  *	-ENOMEM - Not enough memory to map runlist.
  *	-EIO	- Critical error (runlist/file is corrupt, i/o error, etc).
  *
- * Locking: - The runlist must be locked on entry and is left locked on return.
- *	    - If @write_locked is FALSE, i.e. the runlist is locked for reading,
- *	      the lock may be dropped inside the function so you cannot rely on
- *	      the runlist still being the same when this function returns.
+ * WARNING: If @ctx is supplied, regardless of whether success or failure is
+ *	    returned, you need to check IS_ERR(@ctx->mrec) and if TRUE the @ctx
+ *	    is no longer valid, i.e. you need to either call
+ *	    ntfs_attr_reinit_search_ctx() or ntfs_attr_put_search_ctx() on it.
+ *	    In that case PTR_ERR(@ctx->mrec) will give you the error code for
+ *	    why the mapping of the old inode failed.
+ *
+ * Locking: - The runlist described by @ni must be locked for writing on entry
+ *	      and is locked on return.  Note the runlist may be modified when
+ *	      needed runlist fragments need to be mapped.
+ *	    - If @ctx is NULL, the base mft record of @ni must not be mapped on
+ *	      entry and it will be left unmapped on return.
+ *	    - If @ctx is not NULL, the base mft record must be mapped on entry
+ *	      and it will be left mapped on return.
  */
 runlist_element *ntfs_attr_find_vcn_nolock(ntfs_inode *ni, const VCN vcn,
-		const BOOL write_locked)
+		ntfs_attr_search_ctx *ctx)
 {
 	unsigned long flags;
 	runlist_element *rl;
 	int err = 0;
 	BOOL is_retry = FALSE;
 
-	ntfs_debug("Entering for i_ino 0x%lx, vcn 0x%llx, %s_locked.",
-			ni->mft_no, (unsigned long long)vcn,
-			write_locked ? "write" : "read");
+	ntfs_debug("Entering for i_ino 0x%lx, vcn 0x%llx, with%s ctx.",
+			ni->mft_no, (unsigned long long)vcn, ctx ? "" : "out");
 	BUG_ON(!ni);
 	BUG_ON(!NInoNonResident(ni));
 	BUG_ON(vcn < 0);
@@ -312,33 +506,22 @@ retry_remap:
 	}
 	if (!err && !is_retry) {
 		/*
-		 * The @vcn is in an unmapped region, map the runlist and
-		 * retry.
+		 * If the search context is invalid we cannot map the unmapped
+		 * region.
 		 */
-		if (!write_locked) {
-			up_read(&ni->runlist.lock);
-			down_write(&ni->runlist.lock);
-			if (unlikely(ntfs_rl_vcn_to_lcn(ni->runlist.rl, vcn) !=
-					LCN_RL_NOT_MAPPED)) {
-				up_write(&ni->runlist.lock);
-				down_read(&ni->runlist.lock);
+		if (IS_ERR(ctx->mrec))
+			err = PTR_ERR(ctx->mrec);
+		else {
+			/*
+			 * The @vcn is in an unmapped region, map the runlist
+			 * and retry.
+			 */
+			err = ntfs_map_runlist_nolock(ni, vcn, ctx);
+			if (likely(!err)) {
+				is_retry = TRUE;
 				goto retry_remap;
 			}
 		}
-		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 retry_remap;
-		}
-		/*
-		 * -EINVAL coming from a failed mapping attempt is equivalent
-		 * to i/o error for us as it should not happen in our code
-		 * paths.
-		 */
 		if (err == -EINVAL)
 			err = -EIO;
 	} else if (!err)
@@ -1011,6 +1194,7 @@ int ntfs_attr_lookup(const ATTR_TYPE type, const ntfschar *name,
 	ntfs_inode *base_ni;
 
 	ntfs_debug("Entering.");
+	BUG_ON(IS_ERR(ctx->mrec));
 	if (ctx->base_ntfs_ino)
 		base_ni = ctx->base_ntfs_ino;
 	else
@@ -1227,7 +1411,7 @@ int ntfs_attr_can_be_non_resident(const ntfs_volume *vol, const ATTR_TYPE type)
  */
 int ntfs_attr_can_be_resident(const ntfs_volume *vol, const ATTR_TYPE type)
 {
-	if (type == AT_INDEX_ALLOCATION || type == AT_EA)
+	if (type == AT_INDEX_ALLOCATION)
 		return -EPERM;
 	return 0;
 }
@@ -1319,10 +1503,17 @@ int ntfs_resident_attr_value_resize(MFT_RECORD *m, ATTR_RECORD *a,
 /**
  * ntfs_attr_make_non_resident - convert a resident to a non-resident attribute
  * @ni:		ntfs inode describing the attribute to convert
+ * @data_size:	size of the resident data to copy to the non-resident attribute
  *
  * Convert the resident ntfs attribute described by the ntfs inode @ni to a
  * non-resident one.
  *
+ * @data_size must be equal to the attribute value size.  This is needed since
+ * we need to know the size before we can map the mft record and our callers
+ * always know it.  The reason we cannot simply read the size from the vfs
+ * inode i_size is that this is not necessarily uptodate.  This happens when
+ * ntfs_attr_make_non_resident() is called in the ->truncate call path(s).
+ *
  * Return 0 on success and -errno on error.  The following error return codes
  * are defined:
  *	-EPERM	- The attribute is not allowed to be non-resident.
@@ -1343,7 +1534,7 @@ int ntfs_resident_attr_value_resize(MFT_RECORD *m, ATTR_RECORD *a,
  *
  * Locking: - The caller must hold i_sem on the inode.
  */
-int ntfs_attr_make_non_resident(ntfs_inode *ni)
+int ntfs_attr_make_non_resident(ntfs_inode *ni, const u32 data_size)
 {
 	s64 new_size;
 	struct inode *vi = VFS_I(ni);
@@ -1381,11 +1572,9 @@ int ntfs_attr_make_non_resident(ntfs_inode *ni)
 	 * The size needs to be aligned to a cluster boundary for allocation
 	 * purposes.
 	 */
-	new_size = (i_size_read(vi) + vol->cluster_size - 1) &
+	new_size = (data_size + vol->cluster_size - 1) &
 			~(vol->cluster_size - 1);
 	if (new_size > 0) {
-		runlist_element *rl2;
-
 		/*
 		 * Will need the page later and since the page lock nests
 		 * outside all ntfs locks, we need to get the page now.
@@ -1396,7 +1585,7 @@ int ntfs_attr_make_non_resident(ntfs_inode *ni)
 			return -ENOMEM;
 		/* Start by allocating clusters to hold the attribute value. */
 		rl = ntfs_cluster_alloc(vol, 0, new_size >>
-				vol->cluster_size_bits, -1, DATA_ZONE);
+				vol->cluster_size_bits, -1, DATA_ZONE, TRUE);
 		if (IS_ERR(rl)) {
 			err = PTR_ERR(rl);
 			ntfs_debug("Failed to allocate cluster%s, error code "
@@ -1405,12 +1594,6 @@ int ntfs_attr_make_non_resident(ntfs_inode *ni)
 					err);
 			goto page_err_out;
 		}
-		/* Change the runlist terminator to LCN_ENOENT. */
-		rl2 = rl;
-		while (rl2->length)
-			rl2++;
-		BUG_ON(rl2->lcn != LCN_RL_NOT_MAPPED);
-		rl2->lcn = LCN_ENOENT;
 	} else {
 		rl = NULL;
 		page = NULL;
@@ -1473,7 +1656,7 @@ int ntfs_attr_make_non_resident(ntfs_inode *ni)
 	 * attribute value.
 	 */
 	attr_size = le32_to_cpu(a->data.resident.value_length);
-	BUG_ON(attr_size != i_size_read(vi));
+	BUG_ON(attr_size != data_size);
 	if (page && !PageUptodate(page)) {
 		kaddr = kmap_atomic(page, KM_USER0);
 		memcpy(kaddr, (u8*)a +
@@ -1538,7 +1721,9 @@ int ntfs_attr_make_non_resident(ntfs_inode *ni)
 				ffs(ni->itype.compressed.block_size) - 1;
 		ni->itype.compressed.block_clusters = 1U <<
 				a->data.non_resident.compression_unit;
-	}
+		vi->i_blocks = ni->itype.compressed.size >> 9;
+	} else
+		vi->i_blocks = ni->allocated_size >> 9;
 	write_unlock_irqrestore(&ni->size_lock, flags);
 	/*
 	 * This needs to be last since the address space operations ->readpage
@@ -1652,6 +1837,640 @@ page_err_out:
 }
 
 /**
+ * ntfs_attr_extend_allocation - extend the allocated space of an attribute
+ * @ni:			ntfs inode of the attribute whose allocation to extend
+ * @new_alloc_size:	new size in bytes to which to extend the allocation to
+ * @new_data_size:	new size in bytes to which to extend the data to
+ * @data_start:		beginning of region which is required to be non-sparse
+ *
+ * Extend the allocated space of an attribute described by the ntfs inode @ni
+ * to @new_alloc_size bytes.  If @data_start is -1, the whole extension may be
+ * implemented as a hole in the file (as long as both the volume and the ntfs
+ * inode @ni have sparse support enabled).  If @data_start is >= 0, then the
+ * region between the old allocated size and @data_start - 1 may be made sparse
+ * but the regions between @data_start and @new_alloc_size must be backed by
+ * actual clusters.
+ *
+ * If @new_data_size is -1, it is ignored.  If it is >= 0, then the data size
+ * of the attribute is extended to @new_data_size.  Note that the i_size of the
+ * vfs inode is not updated.  Only the data size in the base attribute record
+ * is updated.  The caller has to update i_size separately if this is required.
+ * WARNING: It is a BUG() for @new_data_size to be smaller than the old data
+ * size as well as for @new_data_size to be greater than @new_alloc_size.
+ *
+ * For resident attributes this involves resizing the attribute record and if
+ * necessary moving it and/or other attributes into extent mft records and/or
+ * converting the attribute to a non-resident attribute which in turn involves
+ * extending the allocation of a non-resident attribute as described below.
+ *
+ * For non-resident attributes this involves allocating clusters in the data
+ * zone on the volume (except for regions that are being made sparse) and
+ * extending the run list to describe the allocated clusters as well as
+ * updating the mapping pairs array of the attribute.  This in turn involves
+ * resizing the attribute record and if necessary moving it and/or other
+ * attributes into extent mft records and/or splitting the attribute record
+ * into multiple extent attribute records.
+ *
+ * Also, the attribute list attribute is updated if present and in some of the
+ * above cases (the ones where extent mft records/attributes come into play),
+ * an attribute list attribute is created if not already present.
+ *
+ * Return the new allocated size on success and -errno on error.  In the case
+ * that an error is encountered but a partial extension at least up to
+ * @data_start (if present) is possible, the allocation is partially extended
+ * and this is returned.  This means the caller must check the returned size to
+ * determine if the extension was partial.  If @data_start is -1 then partial
+ * allocations are not performed.
+ *
+ * WARNING: Do not call ntfs_attr_extend_allocation() for $MFT/$DATA.
+ *
+ * Locking: This function takes the runlist lock of @ni for writing as well as
+ * locking the mft record of the base ntfs inode.  These locks are maintained
+ * throughout execution of the function.  These locks are required so that the
+ * attribute can be resized safely and so that it can for example be converted
+ * from resident to non-resident safely.
+ *
+ * TODO: At present attribute list attribute handling is not implemented.
+ *
+ * TODO: At present it is not safe to call this function for anything other
+ * than the $DATA attribute(s) of an uncompressed and unencrypted file.
+ */
+s64 ntfs_attr_extend_allocation(ntfs_inode *ni, s64 new_alloc_size,
+		const s64 new_data_size, const s64 data_start)
+{
+	VCN vcn;
+	s64 ll, allocated_size, start = data_start;
+	struct inode *vi = VFS_I(ni);
+	ntfs_volume *vol = ni->vol;
+	ntfs_inode *base_ni;
+	MFT_RECORD *m;
+	ATTR_RECORD *a;
+	ntfs_attr_search_ctx *ctx;
+	runlist_element *rl, *rl2;
+	unsigned long flags;
+	int err, mp_size;
+	u32 attr_len = 0; /* Silence stupid gcc warning. */
+	BOOL mp_rebuilt;
+
+#ifdef NTFS_DEBUG
+	read_lock_irqsave(&ni->size_lock, flags);
+	allocated_size = ni->allocated_size;
+	read_unlock_irqrestore(&ni->size_lock, flags);
+	ntfs_debug("Entering for i_ino 0x%lx, attribute type 0x%x, "
+			"old_allocated_size 0x%llx, "
+			"new_allocated_size 0x%llx, new_data_size 0x%llx, "
+			"data_start 0x%llx.", vi->i_ino,
+			(unsigned)le32_to_cpu(ni->type),
+			(unsigned long long)allocated_size,
+			(unsigned long long)new_alloc_size,
+			(unsigned long long)new_data_size,
+			(unsigned long long)start);
+#endif
+retry_extend:
+	/*
+	 * For non-resident attributes, @start and @new_size need to be aligned
+	 * to cluster boundaries for allocation purposes.
+	 */
+	if (NInoNonResident(ni)) {
+		if (start > 0)
+			start &= ~(s64)vol->cluster_size_mask;
+		new_alloc_size = (new_alloc_size + vol->cluster_size - 1) &
+				~(s64)vol->cluster_size_mask;
+	}
+	BUG_ON(new_data_size >= 0 && new_data_size > new_alloc_size);
+	/* Check if new size is allowed in $AttrDef. */
+	err = ntfs_attr_size_bounds_check(vol, ni->type, new_alloc_size);
+	if (unlikely(err)) {
+		/* Only emit errors when the write will fail completely. */
+		read_lock_irqsave(&ni->size_lock, flags);
+		allocated_size = ni->allocated_size;
+		read_unlock_irqrestore(&ni->size_lock, flags);
+		if (start < 0 || start >= allocated_size) {
+			if (err == -ERANGE) {
+				ntfs_error(vol->sb, "Cannot extend allocation "
+						"of inode 0x%lx, attribute "
+						"type 0x%x, because the new "
+						"allocation would exceed the "
+						"maximum allowed size for "
+						"this attribute type.",
+						vi->i_ino, (unsigned)
+						le32_to_cpu(ni->type));
+			} else {
+				ntfs_error(vol->sb, "Cannot extend allocation "
+						"of inode 0x%lx, attribute "
+						"type 0x%x, because this "
+						"attribute type is not "
+						"defined on the NTFS volume.  "
+						"Possible corruption!  You "
+						"should run chkdsk!",
+						vi->i_ino, (unsigned)
+						le32_to_cpu(ni->type));
+			}
+		}
+		/* Translate error code to be POSIX conformant for write(2). */
+		if (err == -ERANGE)
+			err = -EFBIG;
+		else
+			err = -EIO;
+		return err;
+	}
+	if (!NInoAttr(ni))
+		base_ni = ni;
+	else
+		base_ni = ni->ext.base_ntfs_ino;
+	/*
+	 * We will be modifying both the runlist (if non-resident) and the mft
+	 * record so lock them both down.
+	 */
+	down_write(&ni->runlist.lock);
+	m = map_mft_record(base_ni);
+	if (IS_ERR(m)) {
+		err = PTR_ERR(m);
+		m = NULL;
+		ctx = NULL;
+		goto err_out;
+	}
+	ctx = ntfs_attr_get_search_ctx(base_ni, m);
+	if (unlikely(!ctx)) {
+		err = -ENOMEM;
+		goto err_out;
+	}
+	read_lock_irqsave(&ni->size_lock, flags);
+	allocated_size = ni->allocated_size;
+	read_unlock_irqrestore(&ni->size_lock, flags);
+	/*
+	 * If non-resident, seek to the last extent.  If resident, there is
+	 * only one extent, so seek to that.
+	 */
+	vcn = NInoNonResident(ni) ? allocated_size >> vol->cluster_size_bits :
+			0;
+	/*
+	 * Abort if someone did the work whilst we waited for the locks.  If we
+	 * just converted the attribute from resident to non-resident it is
+	 * likely that exactly this has happened already.  We cannot quite
+	 * abort if we need to update the data size.
+	 */
+	if (unlikely(new_alloc_size <= allocated_size)) {
+		ntfs_debug("Allocated size already exceeds requested size.");
+		new_alloc_size = allocated_size;
+		if (new_data_size < 0)
+			goto done;
+		/*
+		 * We want the first attribute extent so that we can update the
+		 * data size.
+		 */
+		vcn = 0;
+	}
+	err = ntfs_attr_lookup(ni->type, ni->name, ni->name_len,
+			CASE_SENSITIVE, vcn, NULL, 0, ctx);
+	if (unlikely(err)) {
+		if (err == -ENOENT)
+			err = -EIO;
+		goto err_out;
+	}
+	m = ctx->mrec;
+	a = ctx->attr;
+	/* Use goto to reduce indentation. */
+	if (a->non_resident)
+		goto do_non_resident_extend;
+	BUG_ON(NInoNonResident(ni));
+	/* The total length of the attribute value. */
+	attr_len = le32_to_cpu(a->data.resident.value_length);
+	/*
+	 * Extend the attribute record to be able to store the new attribute
+	 * size.  ntfs_attr_record_resize() will not do anything if the size is
+	 * not changing.
+	 */
+	if (new_alloc_size < vol->mft_record_size &&
+			!ntfs_attr_record_resize(m, a,
+			le16_to_cpu(a->data.resident.value_offset) +
+			new_alloc_size)) {
+		/* The resize succeeded! */
+		write_lock_irqsave(&ni->size_lock, flags);
+		ni->allocated_size = le32_to_cpu(a->length) -
+				le16_to_cpu(a->data.resident.value_offset);
+		write_unlock_irqrestore(&ni->size_lock, flags);
+		if (new_data_size >= 0) {
+			BUG_ON(new_data_size < attr_len);
+			a->data.resident.value_length =
+					cpu_to_le32((u32)new_data_size);
+		}
+		goto flush_done;
+	}
+	/*
+	 * We have to drop all the locks so we can call
+	 * ntfs_attr_make_non_resident().  This could be optimised by try-
+	 * locking the first page cache page and only if that fails dropping
+	 * the locks, locking the page, and redoing all the locking and
+	 * lookups.  While this would be a huge optimisation, it is not worth
+	 * it as this is definitely a slow code path.
+	 */
+	ntfs_attr_put_search_ctx(ctx);
+	unmap_mft_record(base_ni);
+	up_write(&ni->runlist.lock);
+	/*
+	 * Not enough space in the mft record, try to make the attribute
+	 * non-resident and if successful restart the extension process.
+	 */
+	err = ntfs_attr_make_non_resident(ni, attr_len);
+	if (likely(!err))
+		goto retry_extend;
+	/*
+	 * Could not make non-resident.  If this is due to this not being
+	 * permitted for this attribute type or there not being enough space,
+	 * try to make other attributes non-resident.  Otherwise fail.
+	 */
+	if (unlikely(err != -EPERM && err != -ENOSPC)) {
+		/* Only emit errors when the write will fail completely. */
+		read_lock_irqsave(&ni->size_lock, flags);
+		allocated_size = ni->allocated_size;
+		read_unlock_irqrestore(&ni->size_lock, flags);
+		if (start < 0 || start >= allocated_size)
+			ntfs_error(vol->sb, "Cannot extend allocation of "
+					"inode 0x%lx, attribute type 0x%x, "
+					"because the conversion from resident "
+					"to non-resident attribute failed "
+					"with error code %i.", vi->i_ino,
+					(unsigned)le32_to_cpu(ni->type), err);
+		if (err != -ENOMEM)
+			err = -EIO;
+		goto conv_err_out;
+	}
+	/* TODO: Not implemented from here, abort. */
+	read_lock_irqsave(&ni->size_lock, flags);
+	allocated_size = ni->allocated_size;
+	read_unlock_irqrestore(&ni->size_lock, flags);
+	if (start < 0 || start >= allocated_size) {
+		if (err == -ENOSPC)
+			ntfs_error(vol->sb, "Not enough space in the mft "
+					"record/on disk for the non-resident "
+					"attribute value.  This case is not "
+					"implemented yet.");
+		else /* if (err == -EPERM) */
+			ntfs_error(vol->sb, "This attribute type may not be "
+					"non-resident.  This case is not "
+					"implemented yet.");
+	}
+	err = -EOPNOTSUPP;
+	goto conv_err_out;
+#if 0
+	// TODO: Attempt to make other attributes non-resident.
+	if (!err)
+		goto do_resident_extend;
+	/*
+	 * Both the attribute list attribute and the standard information
+	 * attribute must remain in the base inode.  Thus, if this is one of
+	 * these attributes, we have to try to move other attributes out into
+	 * extent mft records instead.
+	 */
+	if (ni->type == AT_ATTRIBUTE_LIST ||
+			ni->type == AT_STANDARD_INFORMATION) {
+		// TODO: Attempt to move other attributes into extent mft
+		// records.
+		err = -EOPNOTSUPP;
+		if (!err)
+			goto do_resident_extend;
+		goto err_out;
+	}
+	// TODO: Attempt to move this attribute to an extent mft record, but
+	// only if it is not already the only attribute in an mft record in
+	// which case there would be nothing to gain.
+	err = -EOPNOTSUPP;
+	if (!err)
+		goto do_resident_extend;
+	/* There is nothing we can do to make enough space. )-: */
+	goto err_out;
+#endif
+do_non_resident_extend:
+	BUG_ON(!NInoNonResident(ni));
+	if (new_alloc_size == allocated_size) {
+		BUG_ON(vcn);
+		goto alloc_done;
+	}
+	/*
+	 * If the data starts after the end of the old allocation, this is a
+	 * $DATA attribute and sparse attributes are enabled on the volume and
+	 * for this inode, then create a sparse region between the old
+	 * allocated size and the start of the data.  Otherwise simply proceed
+	 * with filling the whole space between the old allocated size and the
+	 * new allocated size with clusters.
+	 */
+	if ((start >= 0 && start <= allocated_size) || ni->type != AT_DATA ||
+			!NVolSparseEnabled(vol) || NInoSparseDisabled(ni))
+		goto skip_sparse;
+	// TODO: This is not implemented yet.  We just fill in with real
+	// clusters for now...
+	ntfs_debug("Inserting holes is not-implemented yet.  Falling back to "
+			"allocating real clusters instead.");
+skip_sparse:
+	rl = ni->runlist.rl;
+	if (likely(rl)) {
+		/* Seek to the end of the runlist. */
+		while (rl->length)
+			rl++;
+	}
+	/* If this attribute extent is not mapped, map it now. */
+	if (unlikely(!rl || rl->lcn == LCN_RL_NOT_MAPPED ||
+			(rl->lcn == LCN_ENOENT && rl > ni->runlist.rl &&
+			(rl-1)->lcn == LCN_RL_NOT_MAPPED))) {
+		if (!rl && !allocated_size)
+			goto first_alloc;
+		rl = ntfs_mapping_pairs_decompress(vol, a, ni->runlist.rl);
+		if (IS_ERR(rl)) {
+			err = PTR_ERR(rl);
+			if (start < 0 || start >= allocated_size)
+				ntfs_error(vol->sb, "Cannot extend allocation "
+						"of inode 0x%lx, attribute "
+						"type 0x%x, because the "
+						"mapping of a runlist "
+						"fragment failed with error "
+						"code %i.", vi->i_ino,
+						(unsigned)le32_to_cpu(ni->type),
+						err);
+			if (err != -ENOMEM)
+				err = -EIO;
+			goto err_out;
+		}
+		ni->runlist.rl = rl;
+		/* Seek to the end of the runlist. */
+		while (rl->length)
+			rl++;
+	}
+	/*
+	 * We now know the runlist of the last extent is mapped and @rl is at
+	 * the end of the runlist.  We want to begin allocating clusters
+	 * starting at the last allocated cluster to reduce fragmentation.  If
+	 * there are no valid LCNs in the attribute we let the cluster
+	 * allocator choose the starting cluster.
+	 */
+	/* If the last LCN is a hole or simillar seek back to last real LCN. */
+	while (rl->lcn < 0 && rl > ni->runlist.rl)
+		rl--;
+first_alloc:
+	// FIXME: Need to implement partial allocations so at least part of the
+	// write can be performed when start >= 0.  (Needed for POSIX write(2)
+	// conformance.)
+	rl2 = ntfs_cluster_alloc(vol, allocated_size >> vol->cluster_size_bits,
+			(new_alloc_size - allocated_size) >>
+			vol->cluster_size_bits, (rl && (rl->lcn >= 0)) ?
+			rl->lcn + rl->length : -1, DATA_ZONE, TRUE);
+	if (IS_ERR(rl2)) {
+		err = PTR_ERR(rl2);
+		if (start < 0 || start >= allocated_size)
+			ntfs_error(vol->sb, "Cannot extend allocation of "
+					"inode 0x%lx, attribute type 0x%x, "
+					"because the allocation of clusters "
+					"failed with error code %i.", vi->i_ino,
+					(unsigned)le32_to_cpu(ni->type), err);
+		if (err != -ENOMEM && err != -ENOSPC)
+			err = -EIO;
+		goto err_out;
+	}
+	rl = ntfs_runlists_merge(ni->runlist.rl, rl2);
+	if (IS_ERR(rl)) {
+		err = PTR_ERR(rl);
+		if (start < 0 || start >= allocated_size)
+			ntfs_error(vol->sb, "Cannot extend allocation of "
+					"inode 0x%lx, attribute type 0x%x, "
+					"because the runlist merge failed "
+					"with error code %i.", vi->i_ino,
+					(unsigned)le32_to_cpu(ni->type), err);
+		if (err != -ENOMEM)
+			err = -EIO;
+		if (ntfs_cluster_free_from_rl(vol, rl2)) {
+			ntfs_error(vol->sb, "Failed to release allocated "
+					"cluster(s) in error code path.  Run "
+					"chkdsk to recover the lost "
+					"cluster(s).");
+			NVolSetErrors(vol);
+		}
+		ntfs_free(rl2);
+		goto err_out;
+	}
+	ni->runlist.rl = rl;
+	ntfs_debug("Allocated 0x%llx clusters.", (long long)(new_alloc_size -
+			allocated_size) >> vol->cluster_size_bits);
+	/* Find the runlist element with which the attribute extent starts. */
+	ll = sle64_to_cpu(a->data.non_resident.lowest_vcn);
+	rl2 = ntfs_rl_find_vcn_nolock(rl, ll);
+	BUG_ON(!rl2);
+	BUG_ON(!rl2->length);
+	BUG_ON(rl2->lcn < LCN_HOLE);
+	mp_rebuilt = FALSE;
+	/* Get the size for the new mapping pairs array for this extent. */
+	mp_size = ntfs_get_size_for_mapping_pairs(vol, rl2, ll, -1);
+	if (unlikely(mp_size <= 0)) {
+		err = mp_size;
+		if (start < 0 || start >= allocated_size)
+			ntfs_error(vol->sb, "Cannot extend allocation of "
+					"inode 0x%lx, attribute type 0x%x, "
+					"because determining the size for the "
+					"mapping pairs failed with error code "
+					"%i.", vi->i_ino,
+					(unsigned)le32_to_cpu(ni->type), err);
+		err = -EIO;
+		goto undo_alloc;
+	}
+	/* Extend the attribute record to fit the bigger mapping pairs array. */
+	attr_len = le32_to_cpu(a->length);
+	err = ntfs_attr_record_resize(m, a, mp_size +
+			le16_to_cpu(a->data.non_resident.mapping_pairs_offset));
+	if (unlikely(err)) {
+		BUG_ON(err != -ENOSPC);
+		// TODO: Deal with this by moving this extent to a new mft
+		// record or by starting a new extent in a new mft record,
+		// possibly by extending this extent partially and filling it
+		// and creating a new extent for the remainder, or by making
+		// other attributes non-resident and/or by moving other
+		// attributes out of this mft record.
+		if (start < 0 || start >= allocated_size)
+			ntfs_error(vol->sb, "Not enough space in the mft "
+					"record for the extended attribute "
+					"record.  This case is not "
+					"implemented yet.");
+		err = -EOPNOTSUPP;
+		goto undo_alloc;
+	}
+	mp_rebuilt = TRUE;
+	/* Generate the mapping pairs array directly into the attr record. */
+	err = ntfs_mapping_pairs_build(vol, (u8*)a +
+			le16_to_cpu(a->data.non_resident.mapping_pairs_offset),
+			mp_size, rl2, ll, -1, NULL);
+	if (unlikely(err)) {
+		if (start < 0 || start >= allocated_size)
+			ntfs_error(vol->sb, "Cannot extend allocation of "
+					"inode 0x%lx, attribute type 0x%x, "
+					"because building the mapping pairs "
+					"failed with error code %i.", vi->i_ino,
+					(unsigned)le32_to_cpu(ni->type), err);
+		err = -EIO;
+		goto undo_alloc;
+	}
+	/* Update the highest_vcn. */
+	a->data.non_resident.highest_vcn = cpu_to_sle64((new_alloc_size >>
+			vol->cluster_size_bits) - 1);
+	/*
+	 * We now have extended the allocated size of the attribute.  Reflect
+	 * this in the ntfs_inode structure and the attribute record.
+	 */
+	if (a->data.non_resident.lowest_vcn) {
+		/*
+		 * We are not in the first attribute extent, switch to it, but
+		 * first ensure the changes will make it to disk later.
+		 */
+		flush_dcache_mft_record_page(ctx->ntfs_ino);
+		mark_mft_record_dirty(ctx->ntfs_ino);
+		ntfs_attr_reinit_search_ctx(ctx);
+		err = ntfs_attr_lookup(ni->type, ni->name, ni->name_len,
+				CASE_SENSITIVE, 0, NULL, 0, ctx);
+		if (unlikely(err))
+			goto restore_undo_alloc;
+		/* @m is not used any more so no need to set it. */
+		a = ctx->attr;
+	}
+	write_lock_irqsave(&ni->size_lock, flags);
+	ni->allocated_size = new_alloc_size;
+	a->data.non_resident.allocated_size = cpu_to_sle64(new_alloc_size);
+	/*
+	 * FIXME: This would fail if @ni is a directory, $MFT, or an index,
+	 * since those can have sparse/compressed set.  For example can be
+	 * set compressed even though it is not compressed itself and in that
+	 * case the bit means that files are to be created compressed in the
+	 * directory...  At present this is ok as this code is only called for
+	 * regular files, and only for their $DATA attribute(s).
+	 * FIXME: The calculation is wrong if we created a hole above.  For now
+	 * it does not matter as we never create holes.
+	 */
+	if (NInoSparse(ni) || NInoCompressed(ni)) {
+		ni->itype.compressed.size += new_alloc_size - allocated_size;
+		a->data.non_resident.compressed_size =
+				cpu_to_sle64(ni->itype.compressed.size);
+		vi->i_blocks = ni->itype.compressed.size >> 9;
+	} else
+		vi->i_blocks = new_alloc_size >> 9;
+	write_unlock_irqrestore(&ni->size_lock, flags);
+alloc_done:
+	if (new_data_size >= 0) {
+		BUG_ON(new_data_size <
+				sle64_to_cpu(a->data.non_resident.data_size));
+		a->data.non_resident.data_size = cpu_to_sle64(new_data_size);
+	}
+flush_done:
+	/* Ensure the changes make it to disk. */
+	flush_dcache_mft_record_page(ctx->ntfs_ino);
+	mark_mft_record_dirty(ctx->ntfs_ino);
+done:
+	ntfs_attr_put_search_ctx(ctx);
+	unmap_mft_record(base_ni);
+	up_write(&ni->runlist.lock);
+	ntfs_debug("Done, new_allocated_size 0x%llx.",
+			(unsigned long long)new_alloc_size);
+	return new_alloc_size;
+restore_undo_alloc:
+	if (start < 0 || start >= allocated_size)
+		ntfs_error(vol->sb, "Cannot complete extension of allocation "
+				"of inode 0x%lx, attribute type 0x%x, because "
+				"lookup of first attribute extent failed with "
+				"error code %i.", vi->i_ino,
+				(unsigned)le32_to_cpu(ni->type), err);
+	if (err == -ENOENT)
+		err = -EIO;
+	ntfs_attr_reinit_search_ctx(ctx);
+	if (ntfs_attr_lookup(ni->type, ni->name, ni->name_len, CASE_SENSITIVE,
+			allocated_size >> vol->cluster_size_bits, NULL, 0,
+			ctx)) {
+		ntfs_error(vol->sb, "Failed to find last attribute extent of "
+				"attribute in error code path.  Run chkdsk to "
+				"recover.");
+		write_lock_irqsave(&ni->size_lock, flags);
+		ni->allocated_size = new_alloc_size;
+		/*
+		 * FIXME: This would fail if @ni is a directory...  See above.
+		 * FIXME: The calculation is wrong if we created a hole above.
+		 * For now it does not matter as we never create holes.
+		 */
+		if (NInoSparse(ni) || NInoCompressed(ni)) {
+			ni->itype.compressed.size += new_alloc_size -
+					allocated_size;
+			vi->i_blocks = ni->itype.compressed.size >> 9;
+		} else
+			vi->i_blocks = new_alloc_size >> 9;
+		write_unlock_irqrestore(&ni->size_lock, flags);
+		ntfs_attr_put_search_ctx(ctx);
+		unmap_mft_record(base_ni);
+		up_write(&ni->runlist.lock);
+		/*
+		 * The only thing that is now wrong is the allocated size of the
+		 * base attribute extent which chkdsk should be able to fix.
+		 */
+		NVolSetErrors(vol);
+		return err;
+	}
+	ctx->attr->data.non_resident.highest_vcn = cpu_to_sle64(
+			(allocated_size >> vol->cluster_size_bits) - 1);
+undo_alloc:
+	ll = allocated_size >> vol->cluster_size_bits;
+	if (ntfs_cluster_free(ni, ll, -1, ctx) < 0) {
+		ntfs_error(vol->sb, "Failed to release allocated cluster(s) "
+				"in error code path.  Run chkdsk to recover "
+				"the lost cluster(s).");
+		NVolSetErrors(vol);
+	}
+	m = ctx->mrec;
+	a = ctx->attr;
+	/*
+	 * If the runlist truncation fails and/or the search context is no
+	 * longer valid, we cannot resize the attribute record or build the
+	 * mapping pairs array thus we mark the inode bad so that no access to
+	 * the freed clusters can happen.
+	 */
+	if (ntfs_rl_truncate_nolock(vol, &ni->runlist, ll) || IS_ERR(m)) {
+		ntfs_error(vol->sb, "Failed to %s in error code path.  Run "
+				"chkdsk to recover.", IS_ERR(m) ?
+				"restore attribute search context" :
+				"truncate attribute runlist");
+		make_bad_inode(vi);
+		make_bad_inode(VFS_I(base_ni));
+		NVolSetErrors(vol);
+	} else if (mp_rebuilt) {
+		if (ntfs_attr_record_resize(m, a, attr_len)) {
+			ntfs_error(vol->sb, "Failed to restore attribute "
+					"record in error code path.  Run "
+					"chkdsk to recover.");
+			make_bad_inode(vi);
+			make_bad_inode(VFS_I(base_ni));
+			NVolSetErrors(vol);
+		} else /* if (success) */ {
+			if (ntfs_mapping_pairs_build(vol, (u8*)a + le16_to_cpu(
+					a->data.non_resident.
+					mapping_pairs_offset), attr_len -
+					le16_to_cpu(a->data.non_resident.
+					mapping_pairs_offset), rl2, ll, -1,
+					NULL)) {
+				ntfs_error(vol->sb, "Failed to restore "
+						"mapping pairs array in error "
+						"code path.  Run chkdsk to "
+						"recover.");
+				make_bad_inode(vi);
+				make_bad_inode(VFS_I(base_ni));
+				NVolSetErrors(vol);
+			}
+			flush_dcache_mft_record_page(ctx->ntfs_ino);
+			mark_mft_record_dirty(ctx->ntfs_ino);
+		}
+	}
+err_out:
+	if (ctx)
+		ntfs_attr_put_search_ctx(ctx);
+	if (m)
+		unmap_mft_record(base_ni);
+	up_write(&ni->runlist.lock);
+conv_err_out:
+	ntfs_debug("Failed.  Returning error code %i.", err);
+	return err;
+}
+
+/**
  * ntfs_attr_set - fill (a part of) an attribute with a byte
  * @ni:		ntfs inode describing the attribute to fill
  * @ofs:	offset inside the attribute at which to start to fill
@@ -1773,6 +2592,8 @@ int ntfs_attr_set(ntfs_inode *ni, const s64 ofs, const s64 cnt, const u8 val)
 		/* Finally unlock and release the page. */
 		unlock_page(page);
 		page_cache_release(page);
+		balance_dirty_pages_ratelimited(mapping);
+		cond_resched();
 	}
 	/* If there is a last partial page, need to do it the slow way. */
 	if (end_ofs) {