ext4: move i_size,i_disksize update routines to helper function

Cc: stable@vger.kernel.org # needed for bug fix patches
Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

3 files changed, 28 insertions, 39 deletions

diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 4d95c3301775..b0c225cdb52c 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -2454,6 +2454,22 @@ static inline void ext4_update_i_disksize(struct inode *inode, loff_t newsize)
         up_write(&EXT4_I(inode)->i_data_sem);
 }
 
+/* Update i_size, i_disksize. Requires i_mutex to avoid races with truncate */
+static inline int ext4_update_inode_size(struct inode *inode, loff_t newsize)
+{
+        int changed = 0;
+
+        if (newsize > inode->i_size) {
+                i_size_write(inode, newsize);
+                changed = 1;
+        }
+        if (newsize > EXT4_I(inode)->i_disksize) {
+                ext4_update_i_disksize(inode, newsize);
+                changed |= 2;
+        }
+        return changed;
+}
+
 struct ext4_group_info {
         unsigned long   bb_state;
         struct rb_root  bb_free_root;
diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index 76c2df382b7d..f0e6934291dd 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -4839,12 +4839,8 @@ static long ext4_zero_range(struct file *file, loff_t offset,
         }
 
         inode->i_mtime = inode->i_ctime = ext4_current_time(inode);
-
         if (new_size) {
-                if (new_size > i_size_read(inode))
-                        i_size_write(inode, new_size);
-                if (new_size > EXT4_I(inode)->i_disksize)
-                        ext4_update_i_disksize(inode, new_size);
+                ext4_update_inode_size(inode, new_size);
         } else {
                 /*
                 * Mark that we allocate beyond EOF so the subsequent truncate
@@ -4886,7 +4882,6 @@ long ext4_fallocate(struct file *file, int mode, loff_t offset, loff_t len)
         int ret = 0;
         int flags;
         ext4_lblk_t lblk;
-        struct timespec tv;
         unsigned int blkbits = inode->i_blkbits;
 
         /* Return error if mode is not supported */
@@ -4945,15 +4940,11 @@ long ext4_fallocate(struct file *file, int mode, loff_t offset, loff_t len)
         if (IS_ERR(handle))
                 goto out;
 
-        tv = inode->i_ctime = ext4_current_time(inode);
+        inode->i_ctime = ext4_current_time(inode);
 
         if (new_size) {
-                if (new_size > i_size_read(inode)) {
-                        i_size_write(inode, new_size);
-                        inode->i_mtime = tv;
-                }
-                if (new_size > EXT4_I(inode)->i_disksize)
-                        ext4_update_i_disksize(inode, new_size);
+                if (ext4_update_inode_size(inode, new_size) & 0x1)
+                        inode->i_mtime = inode->i_ctime;
         } else {
                 /*
                 * Mark that we allocate beyond EOF so the subsequent truncate
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 367a60c07cf0..b1ddd9352644 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -1055,27 +1055,11 @@ static int ext4_write_end(struct file *file,
         } else
                 copied = block_write_end(file, mapping, pos,
                                          len, copied, page, fsdata);
-
         /*
-         * No need to use i_size_read() here, the i_size
-         * cannot change under us because we hole i_mutex.
-         *
-         * But it's important to update i_size while still holding page lock:
+         * it's important to update i_size while still holding page lock:
          * page writeout could otherwise come in and zero beyond i_size.
          */
-        if (pos + copied > inode->i_size) {
-                i_size_write(inode, pos + copied);
-                i_size_changed = 1;
-        }
-
-        if (pos + copied > EXT4_I(inode)->i_disksize) {
-                /* We need to mark inode dirty even if
-                 * new_i_size is less that inode->i_size
-                 * but greater than i_disksize. (hint delalloc)
-                 */
-                ext4_update_i_disksize(inode, (pos + copied));
-                i_size_changed = 1;
-        }
+        i_size_changed = ext4_update_inode_size(inode, pos + copied);
         unlock_page(page);
         page_cache_release(page);
 
@@ -1123,7 +1107,7 @@ static int ext4_journalled_write_end(struct file *file,
         int ret = 0, ret2;
         int partial = 0;
         unsigned from, to;
-        loff_t new_i_size;
+        int size_changed = 0;
 
         trace_ext4_journalled_write_end(inode, pos, len, copied);
         from = pos & (PAGE_CACHE_SIZE - 1);
@@ -1146,20 +1130,18 @@ static int ext4_journalled_write_end(struct file *file,
                 if (!partial)
                         SetPageUptodate(page);
         }
-        new_i_size = pos + copied;
-        if (new_i_size > inode->i_size)
-                i_size_write(inode, pos+copied);
+        size_changed = ext4_update_inode_size(inode, pos + copied);
         ext4_set_inode_state(inode, EXT4_STATE_JDATA);
         EXT4_I(inode)->i_datasync_tid = handle->h_transaction->t_tid;
-        if (new_i_size > EXT4_I(inode)->i_disksize) {
-                ext4_update_i_disksize(inode, new_i_size);
+        unlock_page(page);
+        page_cache_release(page);
+
+        if (size_changed) {
                 ret2 = ext4_mark_inode_dirty(handle, inode);
                 if (!ret)
                         ret = ret2;
         }
 
-        unlock_page(page);
-        page_cache_release(page);
         if (pos + len > inode->i_size && ext4_can_truncate(inode))
                 /* if we have allocated more blocks and copied
                  * less. We will have blocks allocated outside