]> asedeno.scripts.mit.edu Git - linux.git/commitdiff
ext4: fix ENOSPC handling in DAX page fault handler
authorJan Kara <jack@suse.cz>
Sun, 7 Jan 2018 21:41:01 +0000 (16:41 -0500)
committerTheodore Ts'o <tytso@mit.edu>
Sun, 7 Jan 2018 21:41:01 +0000 (16:41 -0500)
When allocation of underlying block for a page fault fails, we fail the
fault with SIGBUS. However we may well hit ENOSPC just due to lots of
free blocks being held by the running / committing transaction. So
propagate the error from ext4_iomap_begin() and implement do standard
allocation retry loop in ext4_dax_huge_fault().

Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
fs/ext4/file.c

index 1c7cd882d998eecc1aec07cdcc6cfff7fb014375..fb6f023622fe116d1af3a8604fb33783f3fdf662 100644 (file)
@@ -280,7 +280,8 @@ ext4_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
 static int ext4_dax_huge_fault(struct vm_fault *vmf,
                enum page_entry_size pe_size)
 {
-       int result;
+       int result, error = 0;
+       int retries = 0;
        handle_t *handle = NULL;
        struct inode *inode = file_inode(vmf->vma->vm_file);
        struct super_block *sb = inode->i_sb;
@@ -304,6 +305,7 @@ static int ext4_dax_huge_fault(struct vm_fault *vmf,
                sb_start_pagefault(sb);
                file_update_time(vmf->vma->vm_file);
                down_read(&EXT4_I(inode)->i_mmap_sem);
+retry:
                handle = ext4_journal_start_sb(sb, EXT4_HT_WRITE_PAGE,
                                               EXT4_DATA_TRANS_BLOCKS(sb));
                if (IS_ERR(handle)) {
@@ -314,9 +316,13 @@ static int ext4_dax_huge_fault(struct vm_fault *vmf,
        } else {
                down_read(&EXT4_I(inode)->i_mmap_sem);
        }
-       result = dax_iomap_fault(vmf, pe_size, &pfn, NULL, &ext4_iomap_ops);
+       result = dax_iomap_fault(vmf, pe_size, &pfn, &error, &ext4_iomap_ops);
        if (write) {
                ext4_journal_stop(handle);
+
+               if ((result & VM_FAULT_ERROR) && error == -ENOSPC &&
+                   ext4_should_retry_alloc(sb, &retries))
+                       goto retry;
                /* Handling synchronous page fault? */
                if (result & VM_FAULT_NEEDDSYNC)
                        result = dax_finish_sync_fault(vmf, pe_size, pfn);