From e2ae766c1b030271b5099b25674e2131d1d1e8c1 Mon Sep 17 00:00:00 2001 From: Jan Kara Date: Sun, 20 Nov 2016 18:51:24 -0500 Subject: [PATCH] ext4: convert DAX faults to iomap infrastructure Convert DAX faults to use iomap infrastructure. We would not have to start transaction in ext4_dax_fault() anymore since ext4_iomap_begin takes care of that but so far we do that to avoid lock inversion of transaction start with DAX entry lock which gets acquired in dax_iomap_fault() before calling ->iomap_begin handler. Signed-off-by: Jan Kara Signed-off-by: Theodore Ts'o --- fs/ext4/file.c | 9 +++++---- fs/ext4/inode.c | 14 +++++++++----- 2 files changed, 14 insertions(+), 9 deletions(-) diff --git a/fs/ext4/file.c b/fs/ext4/file.c index 1953fe3..b5f1844 100644 --- a/fs/ext4/file.c +++ b/fs/ext4/file.c @@ -275,7 +275,7 @@ static int ext4_dax_fault(struct vm_area_struct *vma, struct vm_fault *vmf) if (IS_ERR(handle)) result = VM_FAULT_SIGBUS; else - result = dax_fault(vma, vmf, ext4_dax_get_block); + result = dax_iomap_fault(vma, vmf, &ext4_iomap_ops); if (write) { if (!IS_ERR(handle)) @@ -309,9 +309,10 @@ static int ext4_dax_pmd_fault(struct vm_area_struct *vma, unsigned long addr, if (IS_ERR(handle)) result = VM_FAULT_SIGBUS; - else - result = dax_pmd_fault(vma, addr, pmd, flags, - ext4_dax_get_block); + else { + result = dax_iomap_pmd_fault(vma, addr, pmd, flags, + &ext4_iomap_ops); + } if (write) { if (!IS_ERR(handle)) diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index 29237f2..9de9a5a 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -3369,12 +3369,16 @@ retry: } /* - * If we added blocks beyond i_size we need to make sure they + * If we added blocks beyond i_size, we need to make sure they * will get truncated if we crash before updating i_size in - * ext4_iomap_end(). + * ext4_iomap_end(). For faults we don't need to do that (and + * even cannot because for orphan list operations inode_lock is + * required) - if we happen to instantiate block beyond i_size, + * it is because we race with truncate which has already added + * the inode to the orphan list. */ - if (first_block + map.m_len > - (inode->i_size + (1 << blkbits) - 1) >> blkbits) { + if (!(flags & IOMAP_FAULT) && first_block + map.m_len > + (i_size_read(inode) + (1 << blkbits) - 1) >> blkbits) { int err; err = ext4_orphan_add(handle, inode); @@ -3420,7 +3424,7 @@ static int ext4_iomap_end(struct inode *inode, loff_t offset, loff_t length, int blkbits = inode->i_blkbits; bool truncate = false; - if (!(flags & IOMAP_WRITE)) + if (!(flags & IOMAP_WRITE) || (flags & IOMAP_FAULT)) return 0; handle = ext4_journal_start(inode, EXT4_HT_INODE, 2); -- 2.7.4