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Diffstat (limited to 'fs/ext4/inode.c')
-rw-r--r--fs/ext4/inode.c156
1 files changed, 114 insertions, 42 deletions
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 966c614822cc..f43996884242 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -656,16 +656,32 @@ has_zeroout:
return retval;
}
-static void ext4_end_io_unwritten(struct buffer_head *bh, int uptodate)
+/*
+ * Update EXT4_MAP_FLAGS in bh->b_state. For buffer heads attached to pages
+ * we have to be careful as someone else may be manipulating b_state as well.
+ */
+static void ext4_update_bh_state(struct buffer_head *bh, unsigned long flags)
{
- struct inode *inode = bh->b_assoc_map->host;
- /* XXX: breaks on 32-bit > 16GB. Is that even supported? */
- loff_t offset = (loff_t)(uintptr_t)bh->b_private << inode->i_blkbits;
- int err;
- if (!uptodate)
+ unsigned long old_state;
+ unsigned long new_state;
+
+ flags &= EXT4_MAP_FLAGS;
+
+ /* Dummy buffer_head? Set non-atomically. */
+ if (!bh->b_page) {
+ bh->b_state = (bh->b_state & ~EXT4_MAP_FLAGS) | flags;
return;
- WARN_ON(!buffer_unwritten(bh));
- err = ext4_convert_unwritten_extents(NULL, inode, offset, bh->b_size);
+ }
+ /*
+ * Someone else may be modifying b_state. Be careful! This is ugly but
+ * once we get rid of using bh as a container for mapping information
+ * to pass to / from get_block functions, this can go away.
+ */
+ do {
+ old_state = READ_ONCE(bh->b_state);
+ new_state = (old_state & ~EXT4_MAP_FLAGS) | flags;
+ } while (unlikely(
+ cmpxchg(&bh->b_state, old_state, new_state) != old_state));
}
/* Maximum number of blocks we map for direct IO at once. */
@@ -704,11 +720,16 @@ static int _ext4_get_block(struct inode *inode, sector_t iblock,
ext4_io_end_t *io_end = ext4_inode_aio(inode);
map_bh(bh, inode->i_sb, map.m_pblk);
- bh->b_state = (bh->b_state & ~EXT4_MAP_FLAGS) | map.m_flags;
- if (IS_DAX(inode) && buffer_unwritten(bh) && !io_end) {
+ ext4_update_bh_state(bh, map.m_flags);
+ if (IS_DAX(inode) && buffer_unwritten(bh)) {
+ /*
+ * dgc: I suspect unwritten conversion on ext4+DAX is
+ * fundamentally broken here when there are concurrent
+ * read/write in progress on this inode.
+ */
+ WARN_ON_ONCE(io_end);
bh->b_assoc_map = inode->i_mapping;
bh->b_private = (void *)(unsigned long)iblock;
- bh->b_end_io = ext4_end_io_unwritten;
}
if (io_end && io_end->flag & EXT4_IO_END_UNWRITTEN)
set_buffer_defer_completion(bh);
@@ -1655,7 +1676,7 @@ int ext4_da_get_block_prep(struct inode *inode, sector_t iblock,
return ret;
map_bh(bh, inode->i_sb, map.m_pblk);
- bh->b_state = (bh->b_state & ~EXT4_MAP_FLAGS) | map.m_flags;
+ ext4_update_bh_state(bh, map.m_flags);
if (buffer_unwritten(bh)) {
/* A delayed write to unwritten bh should be marked
@@ -3133,29 +3154,29 @@ static ssize_t ext4_ext_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
* case, we allocate an io_end structure to hook to the iocb.
*/
iocb->private = NULL;
- ext4_inode_aio_set(inode, NULL);
- if (!is_sync_kiocb(iocb)) {
- io_end = ext4_init_io_end(inode, GFP_NOFS);
- if (!io_end) {
- ret = -ENOMEM;
- goto retake_lock;
- }
- /*
- * Grab reference for DIO. Will be dropped in ext4_end_io_dio()
- */
- iocb->private = ext4_get_io_end(io_end);
- /*
- * we save the io structure for current async direct
- * IO, so that later ext4_map_blocks() could flag the
- * io structure whether there is a unwritten extents
- * needs to be converted when IO is completed.
- */
- ext4_inode_aio_set(inode, io_end);
- }
-
if (overwrite) {
get_block_func = ext4_get_block_write_nolock;
} else {
+ ext4_inode_aio_set(inode, NULL);
+ if (!is_sync_kiocb(iocb)) {
+ io_end = ext4_init_io_end(inode, GFP_NOFS);
+ if (!io_end) {
+ ret = -ENOMEM;
+ goto retake_lock;
+ }
+ /*
+ * Grab reference for DIO. Will be dropped in
+ * ext4_end_io_dio()
+ */
+ iocb->private = ext4_get_io_end(io_end);
+ /*
+ * we save the io structure for current async direct
+ * IO, so that later ext4_map_blocks() could flag the
+ * io structure whether there is a unwritten extents
+ * needs to be converted when IO is completed.
+ */
+ ext4_inode_aio_set(inode, io_end);
+ }
get_block_func = ext4_get_block_write;
dio_flags = DIO_LOCKING;
}
@@ -3524,6 +3545,35 @@ int ext4_can_truncate(struct inode *inode)
}
/*
+ * We have to make sure i_disksize gets properly updated before we truncate
+ * page cache due to hole punching or zero range. Otherwise i_disksize update
+ * can get lost as it may have been postponed to submission of writeback but
+ * that will never happen after we truncate page cache.
+ */
+int ext4_update_disksize_before_punch(struct inode *inode, loff_t offset,
+ loff_t len)
+{
+ handle_t *handle;
+ loff_t size = i_size_read(inode);
+
+ WARN_ON(!mutex_is_locked(&inode->i_mutex));
+ if (offset > size || offset + len < size)
+ return 0;
+
+ if (EXT4_I(inode)->i_disksize >= size)
+ return 0;
+
+ handle = ext4_journal_start(inode, EXT4_HT_MISC, 1);
+ if (IS_ERR(handle))
+ return PTR_ERR(handle);
+ ext4_update_i_disksize(inode, size);
+ ext4_mark_inode_dirty(handle, inode);
+ ext4_journal_stop(handle);
+
+ return 0;
+}
+
+/*
* ext4_punch_hole: punches a hole in a file by releaseing the blocks
* associated with the given offset and length
*
@@ -3588,17 +3638,26 @@ int ext4_punch_hole(struct inode *inode, loff_t offset, loff_t length)
}
+ /* Wait all existing dio workers, newcomers will block on i_mutex */
+ ext4_inode_block_unlocked_dio(inode);
+ inode_dio_wait(inode);
+
+ /*
+ * Prevent page faults from reinstantiating pages we have released from
+ * page cache.
+ */
+ down_write(&EXT4_I(inode)->i_mmap_sem);
first_block_offset = round_up(offset, sb->s_blocksize);
last_block_offset = round_down((offset + length), sb->s_blocksize) - 1;
/* Now release the pages and zero block aligned part of pages*/
- if (last_block_offset > first_block_offset)
+ if (last_block_offset > first_block_offset) {
+ ret = ext4_update_disksize_before_punch(inode, offset, length);
+ if (ret)
+ goto out_dio;
truncate_pagecache_range(inode, first_block_offset,
last_block_offset);
-
- /* Wait all existing dio workers, newcomers will block on i_mutex */
- ext4_inode_block_unlocked_dio(inode);
- inode_dio_wait(inode);
+ }
if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))
credits = ext4_writepage_trans_blocks(inode);
@@ -3645,16 +3704,12 @@ int ext4_punch_hole(struct inode *inode, loff_t offset, loff_t length)
if (IS_SYNC(inode))
ext4_handle_sync(handle);
- /* Now release the pages again to reduce race window */
- if (last_block_offset > first_block_offset)
- truncate_pagecache_range(inode, first_block_offset,
- last_block_offset);
-
inode->i_mtime = inode->i_ctime = ext4_current_time(inode);
ext4_mark_inode_dirty(handle, inode);
out_stop:
ext4_journal_stop(handle);
out_dio:
+ up_write(&EXT4_I(inode)->i_mmap_sem);
ext4_inode_resume_unlocked_dio(inode);
out_mutex:
mutex_unlock(&inode->i_mutex);
@@ -4775,11 +4830,13 @@ int ext4_setattr(struct dentry *dentry, struct iattr *attr)
} else
ext4_wait_for_tail_page_commit(inode);
}
+ down_write(&EXT4_I(inode)->i_mmap_sem);
/*
* Truncate pagecache after we've waited for commit
* in data=journal mode to make pages freeable.
*/
truncate_pagecache(inode, inode->i_size);
+ up_write(&EXT4_I(inode)->i_mmap_sem);
}
/*
* We want to call ext4_truncate() even if attr->ia_size ==
@@ -5234,6 +5291,8 @@ int ext4_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
sb_start_pagefault(inode->i_sb);
file_update_time(vma->vm_file);
+
+ down_read(&EXT4_I(inode)->i_mmap_sem);
/* Delalloc case is easy... */
if (test_opt(inode->i_sb, DELALLOC) &&
!ext4_should_journal_data(inode) &&
@@ -5303,6 +5362,19 @@ retry_alloc:
out_ret:
ret = block_page_mkwrite_return(ret);
out:
+ up_read(&EXT4_I(inode)->i_mmap_sem);
sb_end_pagefault(inode->i_sb);
return ret;
}
+
+int ext4_filemap_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
+{
+ struct inode *inode = file_inode(vma->vm_file);
+ int err;
+
+ down_read(&EXT4_I(inode)->i_mmap_sem);
+ err = filemap_fault(vma, vmf);
+ up_read(&EXT4_I(inode)->i_mmap_sem);
+
+ return err;
+}
generated by cgit v1.2.3 (git 2.0.4) at 2024-11-01 00:58:23 +0000