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authorDamien Le Moal <damien.lemoal@opensource.wdc.com>2023-03-29 13:16:01 +0900
committerDamien Le Moal <damien.lemoal@opensource.wdc.com>2023-03-30 20:55:49 +0900
commitc1976bd8f23016d8706973908f2bb0ac0d852a8f (patch)
tree84c1ffa6bbd37a37db5cc45e957320a56d5d77f2 /fs/zonefs
parent197b6b60ae7bc51dd0814953c562833143b292aa (diff)
downloadlwn-c1976bd8f23016d8706973908f2bb0ac0d852a8f.tar.gz
lwn-c1976bd8f23016d8706973908f2bb0ac0d852a8f.zip
zonefs: Always invalidate last cached page on append write
When a direct append write is executed, the append offset may correspond to the last page of a sequential file inode which might have been cached already by buffered reads, page faults with mmap-read or non-direct readahead. To ensure that the on-disk and cached data is consistant for such last cached page, make sure to always invalidate it in zonefs_file_dio_append(). If the invalidation fails, return -EBUSY to userspace to differentiate from IO errors. This invalidation will always be a no-op when the FS block size (device zone write granularity) is equal to the page size (e.g. 4K). Reported-by: Hans Holmberg <Hans.Holmberg@wdc.com> Fixes: 02ef12a663c7 ("zonefs: use REQ_OP_ZONE_APPEND for sync DIO") Cc: stable@vger.kernel.org Signed-off-by: Damien Le Moal <damien.lemoal@opensource.wdc.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Tested-by: Hans Holmberg <hans.holmberg@wdc.com>
Diffstat (limited to 'fs/zonefs')
-rw-r--r--fs/zonefs/file.c14
1 files changed, 14 insertions, 0 deletions
diff --git a/fs/zonefs/file.c b/fs/zonefs/file.c
index 617e4f9db42e..c6ab2732955e 100644
--- a/fs/zonefs/file.c
+++ b/fs/zonefs/file.c
@@ -382,6 +382,7 @@ static ssize_t zonefs_file_dio_append(struct kiocb *iocb, struct iov_iter *from)
struct zonefs_zone *z = zonefs_inode_zone(inode);
struct block_device *bdev = inode->i_sb->s_bdev;
unsigned int max = bdev_max_zone_append_sectors(bdev);
+ pgoff_t start, end;
struct bio *bio;
ssize_t size = 0;
int nr_pages;
@@ -390,6 +391,19 @@ static ssize_t zonefs_file_dio_append(struct kiocb *iocb, struct iov_iter *from)
max = ALIGN_DOWN(max << SECTOR_SHIFT, inode->i_sb->s_blocksize);
iov_iter_truncate(from, max);
+ /*
+ * If the inode block size (zone write granularity) is smaller than the
+ * page size, we may be appending data belonging to the last page of the
+ * inode straddling inode->i_size, with that page already cached due to
+ * a buffered read or readahead. So make sure to invalidate that page.
+ * This will always be a no-op for the case where the block size is
+ * equal to the page size.
+ */
+ start = iocb->ki_pos >> PAGE_SHIFT;
+ end = (iocb->ki_pos + iov_iter_count(from) - 1) >> PAGE_SHIFT;
+ if (invalidate_inode_pages2_range(inode->i_mapping, start, end))
+ return -EBUSY;
+
nr_pages = iov_iter_npages(from, BIO_MAX_VECS);
if (!nr_pages)
return 0;