1 files changed, 902 insertions, 81 deletions

diff --git a/fs/ntfs/attrib.c b/fs/ntfs/attrib.c
index 3f9a4ff42ee5..eda056bac256 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+ *          is no longer valid, i.e. you need to either call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) {