4 files changed, 126 insertions, 95 deletions

diff --git a/fs/gfs2/bmap.c b/fs/gfs2/bmap.c
index 5226c3bfbcf7..a7b586e02693 100644
--- a/fs/gfs2/bmap.c
+++ b/fs/gfs2/bmap.c
@@ -572,22 +572,6 @@ static int gfs2_hole_size(struct inode *inode, sector_t lblock, u64 len,
         return ret;
 }
 
-static inline void bmap_lock(struct gfs2_inode *ip, int create)
-{
-        if (create)
-                down_write(&ip->i_rw_mutex);
-        else
-                down_read(&ip->i_rw_mutex);
-}
-
-static inline void bmap_unlock(struct gfs2_inode *ip, int create)
-{
-        if (create)
-                up_write(&ip->i_rw_mutex);
-        else
-                up_read(&ip->i_rw_mutex);
-}
-
 static inline __be64 *gfs2_indirect_init(struct metapath *mp,
                                          struct gfs2_glock *gl, unsigned int i,
                                          unsigned offset, u64 bn)
@@ -614,15 +598,11 @@ enum alloc_state {
 };
 
 /**
- * gfs2_bmap_alloc - Build a metadata tree of the requested height
+ * gfs2_iomap_alloc - Build a metadata tree of the requested height
  * @inode: The GFS2 inode
- * @lblock: The logical starting block of the extent
- * @bh_map: This is used to return the mapping details
- * @zero_new: True if newly allocated blocks should be zeroed
+ * @iomap: The iomap structure
+ * @flags: iomap flags
  * @mp: The metapath, with proper height information calculated
- * @maxlen: The max number of data blocks to alloc
- * @dblock: Pointer to return the resulting new block
- * @dblks: Pointer to return the number of blocks allocated
  *
  * In this routine we may have to alloc:
  *   i) Indirect blocks to grow the metadata tree height
@@ -635,6 +615,13 @@ enum alloc_state {
  * blocks are available, there will only be one request per bmap call)
  * and uses the state machine to initialise the blocks in order.
  *
+ * Right now, this function will allocate at most one indirect block
+ * worth of data -- with a default block size of 4K, that's slightly
+ * less than 2M.  If this limitation is ever removed to allow huge
+ * allocations, we would probably still want to limit the iomap size we
+ * return to avoid stalling other tasks during huge writes; the next
+ * iomap iteration would then find the blocks already allocated.
+ *
  * Returns: errno on error
  */
 
@@ -649,6 +636,7 @@ static int gfs2_iomap_alloc(struct inode *inode, struct iomap *iomap,
         unsigned dblks = 0;
         unsigned ptrs_per_blk;
         const unsigned end_of_metadata = mp->mp_fheight - 1;
+        int ret;
         enum alloc_state state;
         __be64 *ptr;
         __be64 zero_bn = 0;
@@ -659,6 +647,8 @@ static int gfs2_iomap_alloc(struct inode *inode, struct iomap *iomap,
 
         gfs2_trans_add_meta(ip->i_gl, dibh);
 
+        down_write(&ip->i_rw_mutex);
+
         if (mp->mp_fheight == mp->mp_aheight) {
                 struct buffer_head *bh;
                 int eob;
@@ -694,11 +684,10 @@ static int gfs2_iomap_alloc(struct inode *inode, struct iomap *iomap,
         blks = dblks + iblks;
         i = mp->mp_aheight;
         do {
-                int error;
                 n = blks - alloced;
-                error = gfs2_alloc_blocks(ip, &bn, &n, 0, NULL);
-                if (error)
-                        return error;
+                ret = gfs2_alloc_blocks(ip, &bn, &n, 0, NULL);
+                if (ret)
+                        goto out;
                 alloced += n;
                 if (state != ALLOC_DATA || gfs2_is_jdata(ip))
                         gfs2_trans_add_unrevoke(sdp, bn, n);
@@ -754,7 +743,7 @@ static int gfs2_iomap_alloc(struct inode *inode, struct iomap *iomap,
                         dblks = n;
                         ptr = metapointer(end_of_metadata, mp);
                         iomap->addr = bn << inode->i_blkbits;
-                        iomap->flags |= IOMAP_F_NEW;
+                        iomap->flags |= IOMAP_F_MERGED | IOMAP_F_NEW;
                         while (n-- > 0)
                                 *ptr++ = cpu_to_be64(bn++);
                         break;
@@ -764,8 +753,10 @@ static int gfs2_iomap_alloc(struct inode *inode, struct iomap *iomap,
         iomap->length = (u64)dblks << inode->i_blkbits;
         ip->i_height = mp->mp_fheight;
         gfs2_add_inode_blocks(&ip->i_inode, alloced);
-        gfs2_dinode_out(ip, mp->mp_bh[0]->b_data);
-        return 0;
+        gfs2_dinode_out(ip, dibh->b_data);
+out:
+        up_write(&ip->i_rw_mutex);
+        return ret;
 }
 
 static void gfs2_stuffed_iomap(struct inode *inode, struct iomap *iomap)
@@ -781,110 +772,130 @@ static void gfs2_stuffed_iomap(struct inode *inode, struct iomap *iomap)
 }
 
 /**
- * gfs2_iomap_begin - Map blocks from an inode to disk blocks
+ * gfs2_iomap_get - Map blocks from an inode to disk blocks
  * @inode: The inode
  * @pos: Starting position in bytes
  * @length: Length to map, in bytes
  * @flags: iomap flags
  * @iomap: The iomap structure
+ * @mp: The metapath
  *
  * Returns: errno
  */
-int gfs2_iomap_begin(struct inode *inode, loff_t pos, loff_t length,
-                     unsigned flags, struct iomap *iomap)
+static int gfs2_iomap_get(struct inode *inode, loff_t pos, loff_t length,
+                          unsigned flags, struct iomap *iomap,
+                          struct metapath *mp)
 {
         struct gfs2_inode *ip = GFS2_I(inode);
         struct gfs2_sbd *sdp = GFS2_SB(inode);
-        struct metapath mp = { .mp_aheight = 1, };
         __be64 *ptr;
         sector_t lblock;
-        sector_t lend;
-        int ret = 0;
+        sector_t lblock_stop;
+        int ret;
         int eob;
-        unsigned int len;
+        u64 len;
         struct buffer_head *bh;
         u8 height;
 
-        trace_gfs2_iomap_start(ip, pos, length, flags);
-        if (!length) {
-                ret = -EINVAL;
-                goto out;
-        }
+        if (!length)
+                return -EINVAL;
 
         if (gfs2_is_stuffed(ip)) {
                 if (flags & IOMAP_REPORT) {
+                        if (pos >= i_size_read(inode))
+                                return -ENOENT;
                         gfs2_stuffed_iomap(inode, iomap);
-                        if (pos >= iomap->length)
-                                ret = -ENOENT;
-                        goto out;
+                        return 0;
                 }
                 BUG_ON(!(flags & IOMAP_WRITE));
         }
-
         lblock = pos >> inode->i_blkbits;
-        lend = (pos + length + sdp->sd_sb.sb_bsize - 1) >> inode->i_blkbits;
-        len = lend - lblock;
-
         iomap->offset = lblock << inode->i_blkbits;
-        iomap->addr = IOMAP_NULL_ADDR;
-        iomap->type = IOMAP_HOLE;
-        iomap->length = (u64)(lend - lblock) << inode->i_blkbits;
-        iomap->flags = IOMAP_F_MERGED;
-        bmap_lock(ip, flags & IOMAP_WRITE);
+        lblock_stop = (pos + length - 1) >> inode->i_blkbits;
+        len = lblock_stop - lblock + 1;
+
+        down_read(&ip->i_rw_mutex);
 
-        ret = gfs2_meta_inode_buffer(ip, &mp.mp_bh[0]);
+        ret = gfs2_meta_inode_buffer(ip, &mp->mp_bh[0]);
         if (ret)
-                goto out_release;
+                goto unlock;
 
         height = ip->i_height;
         while ((lblock + 1) * sdp->sd_sb.sb_bsize > sdp->sd_heightsize[height])
                 height++;
-        find_metapath(sdp, lblock, &mp, height);
+        find_metapath(sdp, lblock, mp, height);
         if (height > ip->i_height || gfs2_is_stuffed(ip))
                 goto do_alloc;
 
-        ret = lookup_metapath(ip, &mp);
+        ret = lookup_metapath(ip, mp);
         if (ret)
-                goto out_release;
+                goto unlock;
 
-        if (mp.mp_aheight != ip->i_height)
+        if (mp->mp_aheight != ip->i_height)
                 goto do_alloc;
 
-        ptr = metapointer(ip->i_height - 1, &mp);
+        ptr = metapointer(ip->i_height - 1, mp);
         if (*ptr == 0)
                 goto do_alloc;
 
-        iomap->type = IOMAP_MAPPED;
-        iomap->addr = be64_to_cpu(*ptr) << inode->i_blkbits;
+        bh = mp->mp_bh[ip->i_height - 1];
+        len = gfs2_extent_length(bh->b_data, bh->b_size, ptr, len, &eob);
 
-        bh = mp.mp_bh[ip->i_height - 1];
-        len = gfs2_extent_length(bh->b_data, bh->b_size, ptr, lend - lblock, &eob);
+        iomap->addr = be64_to_cpu(*ptr) << inode->i_blkbits;
+        iomap->length = len << inode->i_blkbits;
+        iomap->type = IOMAP_MAPPED;
+        iomap->flags = IOMAP_F_MERGED;
         if (eob)
                 iomap->flags |= IOMAP_F_BOUNDARY;
-        iomap->length = (u64)len << inode->i_blkbits;
 
-out_release:
-        release_metapath(&mp);
-        bmap_unlock(ip, flags & IOMAP_WRITE);
 out:
-        trace_gfs2_iomap_end(ip, iomap, ret);
+        iomap->bdev = inode->i_sb->s_bdev;
+unlock:
+        up_read(&ip->i_rw_mutex);
         return ret;
 
 do_alloc:
-        if (flags & IOMAP_WRITE) {
-                ret = gfs2_iomap_alloc(inode, iomap, flags, &mp);
-        } else if (flags & IOMAP_REPORT) {
+        iomap->addr = IOMAP_NULL_ADDR;
+        iomap->length = len << inode->i_blkbits;
+        iomap->type = IOMAP_HOLE;
+        iomap->flags = 0;
+        if (flags & IOMAP_REPORT) {
                 loff_t size = i_size_read(inode);
                 if (pos >= size)
                         ret = -ENOENT;
-                else if (height <= ip->i_height)
-                        ret = gfs2_hole_size(inode, lblock, len, &mp, iomap);
+                else if (height == ip->i_height)
+                        ret = gfs2_hole_size(inode, lblock, len, mp, iomap);
                 else
                         iomap->length = size - pos;
         }
-        goto out_release;
+        goto out;
 }
 
+static int gfs2_iomap_begin(struct inode *inode, loff_t pos, loff_t length,
+                            unsigned flags, struct iomap *iomap)
+{
+        struct gfs2_inode *ip = GFS2_I(inode);
+        struct metapath mp = { .mp_aheight = 1, };
+        int ret;
+
+        trace_gfs2_iomap_start(ip, pos, length, flags);
+        if (flags & IOMAP_WRITE) {
+                ret = gfs2_iomap_get(inode, pos, length, flags, iomap, &mp);
+                if (!ret && iomap->type == IOMAP_HOLE)
+                        ret = gfs2_iomap_alloc(inode, iomap, flags, &mp);
+                release_metapath(&mp);
+        } else {
+                ret = gfs2_iomap_get(inode, pos, length, flags, iomap, &mp);
+                release_metapath(&mp);
+        }
+        trace_gfs2_iomap_end(ip, iomap, ret);
+        return ret;
+}
+
+const struct iomap_ops gfs2_iomap_ops = {
+        .iomap_begin = gfs2_iomap_begin,
+};
+
 /**
  * gfs2_block_map - Map one or more blocks of an inode to a disk block
  * @inode: The inode
@@ -910,25 +921,34 @@ int gfs2_block_map(struct inode *inode, sector_t lblock,
                    struct buffer_head *bh_map, int create)
 {
         struct gfs2_inode *ip = GFS2_I(inode);
-        struct iomap iomap;
-        int ret, flags = 0;
+        loff_t pos = (loff_t)lblock << inode->i_blkbits;
+        loff_t length = bh_map->b_size;
+        struct metapath mp = { .mp_aheight = 1, };
+        struct iomap iomap = { };
+        int ret;
 
         clear_buffer_mapped(bh_map);
         clear_buffer_new(bh_map);
         clear_buffer_boundary(bh_map);
         trace_gfs2_bmap(ip, bh_map, lblock, create, 1);
 
-        if (create)
-                flags |= IOMAP_WRITE;
-        ret = gfs2_iomap_begin(inode, (loff_t)lblock << inode->i_blkbits,
-                               bh_map->b_size, flags, &iomap);
-        if (ret) {
-                if (!create && ret == -ENOENT) {
-                        /* Return unmapped buffer beyond the end of file.  */
+        if (create) {
+                ret = gfs2_iomap_get(inode, pos, length, IOMAP_WRITE, &iomap, &mp);
+                if (!ret && iomap.type == IOMAP_HOLE)
+                        ret = gfs2_iomap_alloc(inode, &iomap, IOMAP_WRITE, &mp);
+                release_metapath(&mp);
+        } else {
+                ret = gfs2_iomap_get(inode, pos, length, 0, &iomap, &mp);
+                release_metapath(&mp);
+
+                /* Return unmapped buffer beyond the end of file. */
+                if (ret == -ENOENT) {
                         ret = 0;
+                        goto out;
                 }
-                goto out;
         }
+        if (ret)
+                goto out;
 
         if (iomap.length > bh_map->b_size) {
                 iomap.length = bh_map->b_size;
@@ -1143,6 +1163,19 @@ out:
         return error;
 }
 
+int gfs2_iomap_get_alloc(struct inode *inode, loff_t pos, loff_t length,
+                         struct iomap *iomap)
+{
+        struct metapath mp = { .mp_aheight = 1, };
+        int ret;
+
+        ret = gfs2_iomap_get(inode, pos, length, IOMAP_WRITE, iomap, &mp);
+        if (!ret && iomap->type == IOMAP_HOLE)
+                ret = gfs2_iomap_alloc(inode, iomap, IOMAP_WRITE, &mp);
+        release_metapath(&mp);
+        return ret;
+}
+
 /**
  * sweep_bh_for_rgrps - find an rgrp in a meta buffer and free blocks therein
  * @ip: inode
diff --git a/fs/gfs2/bmap.h b/fs/gfs2/bmap.h
index c3402fe00653..6b18fb323f0a 100644
--- a/fs/gfs2/bmap.h
+++ b/fs/gfs2/bmap.h
@@ -46,11 +46,13 @@ static inline void gfs2_write_calc_reserv(const struct gfs2_inode *ip,
         }
 }
 
+extern const struct iomap_ops gfs2_iomap_ops;
+
 extern int gfs2_unstuff_dinode(struct gfs2_inode *ip, struct page *page);
 extern int gfs2_block_map(struct inode *inode, sector_t lblock,
                           struct buffer_head *bh, int create);
-extern int gfs2_iomap_begin(struct inode *inode, loff_t pos, loff_t length,
-                            unsigned flags, struct iomap *iomap);
+extern int gfs2_iomap_get_alloc(struct inode *inode, loff_t pos, loff_t length,
+                                struct iomap *iomap);
 extern int gfs2_extent_map(struct inode *inode, u64 lblock, int *new,
                            u64 *dblock, unsigned *extlen);
 extern int gfs2_setattr_size(struct inode *inode, u64 size);
diff --git a/fs/gfs2/file.c b/fs/gfs2/file.c
index 4b71f021a9e2..7137db7b0119 100644
--- a/fs/gfs2/file.c
+++ b/fs/gfs2/file.c
@@ -733,7 +733,7 @@ static int fallocate_chunk(struct inode *inode, loff_t offset, loff_t len,
         struct gfs2_inode *ip = GFS2_I(inode);
         loff_t end = offset + len;
         struct buffer_head *dibh;
-        struct iomap iomap;
+        struct iomap iomap = { };
         int error;
 
         error = gfs2_meta_inode_buffer(ip, &dibh);
@@ -749,8 +749,8 @@ static int fallocate_chunk(struct inode *inode, loff_t offset, loff_t len,
         }
 
         while (offset < end) {
-                error = gfs2_iomap_begin(inode, offset, end - offset,
-                                         IOMAP_WRITE, &iomap);
+                error = gfs2_iomap_get_alloc(inode, offset, end - offset,
+                                             &iomap);
                 if (error)
                         goto out;
                 offset = iomap.offset + iomap.length;
diff --git a/fs/gfs2/inode.c b/fs/gfs2/inode.c
index 8700eb815638..feda55f67050 100644
--- a/fs/gfs2/inode.c
+++ b/fs/gfs2/inode.c
@@ -2006,10 +2006,6 @@ static int gfs2_getattr(const struct path *path, struct kstat *stat,
         return 0;
 }
 
-const struct iomap_ops gfs2_iomap_ops = {
-        .iomap_begin = gfs2_iomap_begin,
-};
-
 static int gfs2_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
                        u64 start, u64 len)
 {