In preparation for implementing the direct IO write code path modifications that make us of iomap infrastructure we need to move out the inode extension/truncate code from ext4_iomap_end() callback. For direct IO, if the current code remained it would behave incorrectly. If we update the inode size prior to converting unwritten extents we run the risk of allowing a racing direct IO read operation to find unwritten extents before they are converted. The inode extension/truncate has been moved out into a new function ext4_handle_inode_extension(). This will be used by both direct IO and DAX code paths if the write results with the inode being extended. Signed-off-by: Matthew Bobrowski <mbobrowski@xxxxxxxxxxxxxx> --- fs/ext4/file.c | 60 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++- fs/ext4/inode.c | 48 +-------------------------------------------- 2 files changed, 60 insertions(+), 48 deletions(-) diff --git a/fs/ext4/file.c b/fs/ext4/file.c index 360eff7b6aa2..7470800c63b7 100644 --- a/fs/ext4/file.c +++ b/fs/ext4/file.c @@ -33,6 +33,7 @@ #include "ext4_jbd2.h" #include "xattr.h" #include "acl.h" +#include "truncate.h" static bool ext4_dio_checks(struct inode *inode) { @@ -234,12 +235,62 @@ static ssize_t ext4_write_checks(struct kiocb *iocb, struct iov_iter *from) return iov_iter_count(from); } +static int ext4_handle_inode_extension(struct inode *inode, loff_t size, + size_t count) +{ + handle_t *handle; + bool truncate = false; + ext4_lblk_t written_blk, end_blk; + int ret = 0, blkbits = inode->i_blkbits; + + handle = ext4_journal_start(inode, EXT4_HT_INODE, 2); + if (IS_ERR(handle)) { + ret = PTR_ERR(handle); + goto orphan_del; + } + + if (ext4_update_inode_size(inode, size)) + ext4_mark_inode_dirty(handle, inode); + + /* + * We may need truncate allocated but not written blocks + * beyond EOF. + */ + written_blk = ALIGN(size, 1 << blkbits); + end_blk = ALIGN(size + count, 1 << blkbits); + if (written_blk < end_blk && ext4_can_truncate(inode)) + truncate = true; + + /* + * Remove the inode from the orphan list if it has been + * extended and everything went OK. + */ + if (!truncate && inode->i_nlink) + ext4_orphan_del(handle, inode); + ext4_journal_stop(handle); + + if (truncate) { + ext4_truncate_failed_write(inode); +orphan_del: + /* + * If the truncate operation failed early the inode + * may still be on the orphan list. In that case, we + * need try remove the inode from the linked list in + * memory. + */ + if (inode->i_nlink) + ext4_orphan_del(NULL, inode); + } + return ret; +} + #ifdef CONFIG_FS_DAX static ssize_t ext4_dax_write_iter(struct kiocb *iocb, struct iov_iter *from) { - struct inode *inode = file_inode(iocb->ki_filp); + int err; ssize_t ret; + struct inode *inode = file_inode(iocb->ki_filp); if (!inode_trylock(inode)) { if (iocb->ki_flags & IOCB_NOWAIT) @@ -257,6 +308,13 @@ ext4_dax_write_iter(struct kiocb *iocb, struct iov_iter *from) goto out; ret = dax_iomap_rw(iocb, from, &ext4_iomap_ops); + + if (ret > 0 && iocb->ki_pos > i_size_read(inode)) { + err = ext4_handle_inode_extension(inode, iocb->ki_pos, + iov_iter_count(from)); + if (err) + ret = err; + } out: inode_unlock(inode); if (ret > 0) diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index 420fe3deed39..761ce6286b05 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -3601,53 +3601,7 @@ static int ext4_iomap_begin(struct inode *inode, loff_t offset, loff_t length, static int ext4_iomap_end(struct inode *inode, loff_t offset, loff_t length, ssize_t written, unsigned flags, struct iomap *iomap) { - int ret = 0; - handle_t *handle; - int blkbits = inode->i_blkbits; - bool truncate = false; - - if (!(flags & IOMAP_WRITE) || (flags & IOMAP_FAULT)) - return 0; - - handle = ext4_journal_start(inode, EXT4_HT_INODE, 2); - if (IS_ERR(handle)) { - ret = PTR_ERR(handle); - goto orphan_del; - } - if (ext4_update_inode_size(inode, offset + written)) - ext4_mark_inode_dirty(handle, inode); - /* - * We may need to truncate allocated but not written blocks beyond EOF. - */ - if (iomap->offset + iomap->length > - ALIGN(inode->i_size, 1 << blkbits)) { - ext4_lblk_t written_blk, end_blk; - - written_blk = (offset + written) >> blkbits; - end_blk = (offset + length) >> blkbits; - if (written_blk < end_blk && ext4_can_truncate(inode)) - truncate = true; - } - /* - * Remove inode from orphan list if we were extending a inode and - * everything went fine. - */ - if (!truncate && inode->i_nlink && - !list_empty(&EXT4_I(inode)->i_orphan)) - ext4_orphan_del(handle, inode); - ext4_journal_stop(handle); - if (truncate) { - ext4_truncate_failed_write(inode); -orphan_del: - /* - * If truncate failed early the inode might still be on the - * orphan list; we need to make sure the inode is removed from - * the orphan list in that case. - */ - if (inode->i_nlink) - ext4_orphan_del(NULL, inode); - } - return ret; + return 0; } const struct iomap_ops ext4_iomap_ops = { -- 2.16.4 -- Matthew Bobrowski