Illumos #3306, #3321

[zfs.git] / module / zfs / zpl_file.c

diff --git a/module/zfs/zpl_file.c b/module/zfs/zpl_file.c
index 0ef2c15..db6a72c 100644 (file)
--- a/module/zfs/zpl_file.c
+++ b/module/zfs/zpl_file.c
@@ -357,21 +357,16 @@ zpl_putpage(struct page *pp, struct writeback_control *wbc, void *data)
 
        ASSERT(PageLocked(pp));
        ASSERT(!PageWriteback(pp));
+       ASSERT(!(current->flags & PF_NOFS));
 
        /*
-        * Disable the normal reclaim path for zpl_putpage().  This
-        * ensures that all memory allocations under this call path
-        * will never enter direct reclaim.  If this were to happen
-        * the VM might try to write out additional pages by calling
-        * zpl_putpage() again resulting in a deadlock.
+        * Annotate this call path with a flag that indicates that it is
+        * unsafe to use KM_SLEEP during memory allocations due to the
+        * potential for a deadlock.  KM_PUSHPAGE should be used instead.
         */
-       if (current->flags & PF_MEMALLOC) {
-               (void) zfs_putpage(mapping->host, pp, wbc);
-       } else {
-               current->flags |= PF_MEMALLOC;
-               (void) zfs_putpage(mapping->host, pp, wbc);
-               current->flags &= ~PF_MEMALLOC;
-       }
+       current->flags |= PF_NOFS;
+       (void) zfs_putpage(mapping->host, pp, wbc);
+       current->flags &= ~PF_NOFS;
 
        return (0);
 }
@@ -394,6 +389,50 @@ zpl_writepage(struct page *pp, struct writeback_control *wbc)
        return zpl_putpage(pp, wbc, pp->mapping);
 }
 
+/*
+ * The only flag combination which matches the behavior of zfs_space()
+ * is FALLOC_FL_PUNCH_HOLE.  This flag was introduced in the 2.6.38 kernel.
+ */
+long
+zpl_fallocate_common(struct inode *ip, int mode, loff_t offset, loff_t len)
+{
+       cred_t *cr = CRED();
+       int error = -EOPNOTSUPP;
+
+       if (mode & FALLOC_FL_KEEP_SIZE)
+               return (-EOPNOTSUPP);
+
+       crhold(cr);
+
+#ifdef FALLOC_FL_PUNCH_HOLE
+       if (mode & FALLOC_FL_PUNCH_HOLE) {
+               flock64_t bf;
+
+               bf.l_type = F_WRLCK;
+               bf.l_whence = 0;
+               bf.l_start = offset;
+               bf.l_len = len;
+               bf.l_pid = 0;
+
+               error = -zfs_space(ip, F_FREESP, &bf, FWRITE, offset, cr);
+       }
+#endif /* FALLOC_FL_PUNCH_HOLE */
+
+       crfree(cr);
+
+       ASSERT3S(error, <=, 0);
+       return (error);
+}
+
+#ifdef HAVE_FILE_FALLOCATE
+static long
+zpl_fallocate(struct file *filp, int mode, loff_t offset, loff_t len)
+{
+       return zpl_fallocate_common(filp->f_path.dentry->d_inode,
+           mode, offset, len);
+}
+#endif /* HAVE_FILE_FALLOCATE */
+
 const struct address_space_operations zpl_address_space_operations = {
        .readpages      = zpl_readpages,
        .readpage       = zpl_readpage,
@@ -407,9 +446,11 @@ const struct file_operations zpl_file_operations = {
        .llseek         = generic_file_llseek,
        .read           = zpl_read,
        .write          = zpl_write,
-       .readdir        = zpl_readdir,
        .mmap           = zpl_mmap,
        .fsync          = zpl_fsync,
+#ifdef HAVE_FILE_FALLOCATE
+       .fallocate      = zpl_fallocate,
+#endif /* HAVE_FILE_FALLOCATE */
 };
 
 const struct file_operations zpl_dir_file_operations = {