diff options
Diffstat (limited to 'fs/ext4/fsync.c')
| -rw-r--r-- | fs/ext4/fsync.c | 187 |
1 files changed, 187 insertions, 0 deletions
diff --git a/fs/ext4/fsync.c b/fs/ext4/fsync.c new file mode 100644 index 000000000..027a7d703 --- /dev/null +++ b/fs/ext4/fsync.c @@ -0,0 +1,187 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * linux/fs/ext4/fsync.c + * + * Copyright (C) 1993 Stephen Tweedie (sct@redhat.com) + * from + * Copyright (C) 1992 Remy Card (card@masi.ibp.fr) + * Laboratoire MASI - Institut Blaise Pascal + * Universite Pierre et Marie Curie (Paris VI) + * from + * linux/fs/minix/truncate.c Copyright (C) 1991, 1992 Linus Torvalds + * + * ext4fs fsync primitive + * + * Big-endian to little-endian byte-swapping/bitmaps by + * David S. Miller (davem@caip.rutgers.edu), 1995 + * + * Removed unnecessary code duplication for little endian machines + * and excessive __inline__s. + * Andi Kleen, 1997 + * + * Major simplications and cleanup - we only need to do the metadata, because + * we can depend on generic_block_fdatasync() to sync the data blocks. + */ + +#include <linux/time.h> +#include <linux/fs.h> +#include <linux/sched.h> +#include <linux/writeback.h> +#include <linux/blkdev.h> + +#include "ext4.h" +#include "ext4_jbd2.h" + +#include <trace/events/ext4.h> + +/* + * If we're not journaling and this is a just-created file, we have to + * sync our parent directory (if it was freshly created) since + * otherwise it will only be written by writeback, leaving a huge + * window during which a crash may lose the file. This may apply for + * the parent directory's parent as well, and so on recursively, if + * they are also freshly created. + */ +static int ext4_sync_parent(struct inode *inode) +{ + struct dentry *dentry, *next; + int ret = 0; + + if (!ext4_test_inode_state(inode, EXT4_STATE_NEWENTRY)) + return 0; + dentry = d_find_any_alias(inode); + if (!dentry) + return 0; + while (ext4_test_inode_state(inode, EXT4_STATE_NEWENTRY)) { + ext4_clear_inode_state(inode, EXT4_STATE_NEWENTRY); + + next = dget_parent(dentry); + dput(dentry); + dentry = next; + inode = dentry->d_inode; + + /* + * The directory inode may have gone through rmdir by now. But + * the inode itself and its blocks are still allocated (we hold + * a reference to the inode via its dentry), so it didn't go + * through ext4_evict_inode()) and so we are safe to flush + * metadata blocks and the inode. + */ + ret = sync_mapping_buffers(inode->i_mapping); + if (ret) + break; + ret = sync_inode_metadata(inode, 1); + if (ret) + break; + } + dput(dentry); + return ret; +} + +static int ext4_fsync_nojournal(struct inode *inode, bool datasync, + bool *needs_barrier) +{ + int ret, err; + + ret = sync_mapping_buffers(inode->i_mapping); + if (!(inode->i_state & I_DIRTY_ALL)) + return ret; + if (datasync && !(inode->i_state & I_DIRTY_DATASYNC)) + return ret; + + err = sync_inode_metadata(inode, 1); + if (!ret) + ret = err; + + if (!ret) + ret = ext4_sync_parent(inode); + if (test_opt(inode->i_sb, BARRIER)) + *needs_barrier = true; + + return ret; +} + +static int ext4_fsync_journal(struct inode *inode, bool datasync, + bool *needs_barrier) +{ + struct ext4_inode_info *ei = EXT4_I(inode); + journal_t *journal = EXT4_SB(inode->i_sb)->s_journal; + tid_t commit_tid = datasync ? ei->i_datasync_tid : ei->i_sync_tid; + + if (journal->j_flags & JBD2_BARRIER && + !jbd2_trans_will_send_data_barrier(journal, commit_tid)) + *needs_barrier = true; + + return ext4_fc_commit(journal, commit_tid); +} + +/* + * akpm: A new design for ext4_sync_file(). + * + * This is only called from sys_fsync(), sys_fdatasync() and sys_msync(). + * There cannot be a transaction open by this task. + * Another task could have dirtied this inode. Its data can be in any + * state in the journalling system. + * + * What we do is just kick off a commit and wait on it. This will snapshot the + * inode to disk. + */ +int ext4_sync_file(struct file *file, loff_t start, loff_t end, int datasync) +{ + int ret = 0, err; + bool needs_barrier = false; + struct inode *inode = file->f_mapping->host; + struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); + + if (unlikely(ext4_forced_shutdown(sbi))) + return -EIO; + + ASSERT(ext4_journal_current_handle() == NULL); + + trace_ext4_sync_file_enter(file, datasync); + + if (sb_rdonly(inode->i_sb)) { + /* Make sure that we read updated s_mount_flags value */ + smp_rmb(); + if (ext4_test_mount_flag(inode->i_sb, EXT4_MF_FS_ABORTED)) + ret = -EROFS; + goto out; + } + + ret = file_write_and_wait_range(file, start, end); + if (ret) + goto out; + + /* + * data=writeback,ordered: + * The caller's filemap_fdatawrite()/wait will sync the data. + * Metadata is in the journal, we wait for proper transaction to + * commit here. + * + * data=journal: + * filemap_fdatawrite won't do anything (the buffers are clean). + * ext4_force_commit will write the file data into the journal and + * will wait on that. + * filemap_fdatawait() will encounter a ton of newly-dirtied pages + * (they were dirtied by commit). But that's OK - the blocks are + * safe in-journal, which is all fsync() needs to ensure. + */ + if (!sbi->s_journal) + ret = ext4_fsync_nojournal(inode, datasync, &needs_barrier); + else if (ext4_should_journal_data(inode)) + ret = ext4_force_commit(inode->i_sb); + else + ret = ext4_fsync_journal(inode, datasync, &needs_barrier); + + if (needs_barrier) { + err = blkdev_issue_flush(inode->i_sb->s_bdev); + if (!ret) + ret = err; + } +out: + err = file_check_and_advance_wb_err(file); + if (ret == 0) + ret = err; + trace_ext4_sync_file_exit(inode, ret); + return ret; +} |