Merge tag 'lazytime_for_v5.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs
Pull lazytime updates from Jan Kara:
"Cleanups of the lazytime handling in the writeback code making rules
for calling ->dirty_inode() filesystem handlers saner"
* tag 'lazytime_for_v5.12-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs:
ext4: simplify i_state checks in __ext4_update_other_inode_time()
gfs2: don't worry about I_DIRTY_TIME in gfs2_fsync()
fs: improve comments for writeback_single_inode()
fs: drop redundant check from __writeback_single_inode()
fs: clean up __mark_inode_dirty() a bit
fs: pass only I_DIRTY_INODE flags to ->dirty_inode
fs: don't call ->dirty_inode for lazytime timestamp updates
fat: only specify I_DIRTY_TIME when needed in fat_update_time()
fs: only specify I_DIRTY_TIME when needed in generic_update_time()
fs: correctly document the inode dirty flags
diff --git a/Documentation/filesystems/vfs.rst b/Documentation/filesystems/vfs.rst
index 18d69a4..a4d64b1 100644
--- a/Documentation/filesystems/vfs.rst
+++ b/Documentation/filesystems/vfs.rst
@@ -270,7 +270,10 @@
->alloc_inode.
``dirty_inode``
- this method is called by the VFS to mark an inode dirty.
+ this method is called by the VFS when an inode is marked dirty.
+ This is specifically for the inode itself being marked dirty,
+ not its data. If the update needs to be persisted by fdatasync(),
+ then I_DIRTY_DATASYNC will be set in the flags argument.
``write_inode``
this method is called when the VFS needs to write an inode to
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index c173c84..de79052 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -4961,15 +4961,11 @@
if (!inode)
return;
- if ((inode->i_state & (I_FREEING | I_WILL_FREE | I_NEW |
- I_DIRTY_INODE)) ||
- ((inode->i_state & I_DIRTY_TIME) == 0))
+ if (!inode_is_dirtytime_only(inode))
return;
spin_lock(&inode->i_lock);
- if (((inode->i_state & (I_FREEING | I_WILL_FREE | I_NEW |
- I_DIRTY_INODE)) == 0) &&
- (inode->i_state & I_DIRTY_TIME)) {
+ if (inode_is_dirtytime_only(inode)) {
struct ext4_inode_info *ei = EXT4_I(inode);
inode->i_state &= ~I_DIRTY_TIME;
@@ -5937,26 +5933,16 @@
* If the inode is marked synchronous, we don't honour that here - doing
* so would cause a commit on atime updates, which we don't bother doing.
* We handle synchronous inodes at the highest possible level.
- *
- * If only the I_DIRTY_TIME flag is set, we can skip everything. If
- * I_DIRTY_TIME and I_DIRTY_SYNC is set, the only inode fields we need
- * to copy into the on-disk inode structure are the timestamp files.
*/
void ext4_dirty_inode(struct inode *inode, int flags)
{
handle_t *handle;
- if (flags == I_DIRTY_TIME)
- return;
handle = ext4_journal_start(inode, EXT4_HT_INODE, 2);
if (IS_ERR(handle))
- goto out;
-
+ return;
ext4_mark_inode_dirty(handle, inode);
-
ext4_journal_stop(handle);
-out:
- return;
}
int ext4_change_inode_journal_flag(struct inode *inode, int val)
diff --git a/fs/f2fs/super.c b/fs/f2fs/super.c
index 4acfa7d..7069793 100644
--- a/fs/f2fs/super.c
+++ b/fs/f2fs/super.c
@@ -1300,9 +1300,6 @@
inode->i_ino == F2FS_META_INO(sbi))
return;
- if (flags == I_DIRTY_TIME)
- return;
-
if (is_inode_flag_set(inode, FI_AUTO_RECOVER))
clear_inode_flag(inode, FI_AUTO_RECOVER);
diff --git a/fs/fat/misc.c b/fs/fat/misc.c
index f1b2a1f..18a50a4 100644
--- a/fs/fat/misc.c
+++ b/fs/fat/misc.c
@@ -329,22 +329,23 @@
int fat_update_time(struct inode *inode, struct timespec64 *now, int flags)
{
- int iflags = I_DIRTY_TIME;
- bool dirty = false;
+ int dirty_flags = 0;
if (inode->i_ino == MSDOS_ROOT_INO)
return 0;
- fat_truncate_time(inode, now, flags);
- if (flags & S_VERSION)
- dirty = inode_maybe_inc_iversion(inode, false);
- if ((flags & (S_ATIME | S_CTIME | S_MTIME)) &&
- !(inode->i_sb->s_flags & SB_LAZYTIME))
- dirty = true;
+ if (flags & (S_ATIME | S_CTIME | S_MTIME)) {
+ fat_truncate_time(inode, now, flags);
+ if (inode->i_sb->s_flags & SB_LAZYTIME)
+ dirty_flags |= I_DIRTY_TIME;
+ else
+ dirty_flags |= I_DIRTY_SYNC;
+ }
- if (dirty)
- iflags |= I_DIRTY_SYNC;
- __mark_inode_dirty(inode, iflags);
+ if ((flags & S_VERSION) && inode_maybe_inc_iversion(inode, false))
+ dirty_flags |= I_DIRTY_SYNC;
+
+ __mark_inode_dirty(inode, dirty_flags);
return 0;
}
EXPORT_SYMBOL_GPL(fat_update_time);
diff --git a/fs/fs-writeback.c b/fs/fs-writeback.c
index c41cb88..e91980f 100644
--- a/fs/fs-writeback.c
+++ b/fs/fs-writeback.c
@@ -1442,9 +1442,15 @@
}
/*
- * Write out an inode and its dirty pages. Do not update the writeback list
- * linkage. That is left to the caller. The caller is also responsible for
- * setting I_SYNC flag and calling inode_sync_complete() to clear it.
+ * Write out an inode and its dirty pages (or some of its dirty pages, depending
+ * on @wbc->nr_to_write), and clear the relevant dirty flags from i_state.
+ *
+ * This doesn't remove the inode from the writeback list it is on, except
+ * potentially to move it from b_dirty_time to b_dirty due to timestamp
+ * expiration. The caller is otherwise responsible for writeback list handling.
+ *
+ * The caller is also responsible for setting the I_SYNC flag beforehand and
+ * calling inode_sync_complete() to clear it afterwards.
*/
static int
__writeback_single_inode(struct inode *inode, struct writeback_control *wbc)
@@ -1479,7 +1485,7 @@
* change I_DIRTY_TIME into I_DIRTY_SYNC.
*/
if ((inode->i_state & I_DIRTY_TIME) &&
- (wbc->sync_mode == WB_SYNC_ALL || wbc->for_sync ||
+ (wbc->sync_mode == WB_SYNC_ALL ||
time_after(jiffies, inode->dirtied_time_when +
dirtytime_expire_interval * HZ))) {
trace_writeback_lazytime(inode);
@@ -1487,9 +1493,10 @@
}
/*
- * Some filesystems may redirty the inode during the writeback
- * due to delalloc, clear dirty metadata flags right before
- * write_inode()
+ * Get and clear the dirty flags from i_state. This needs to be done
+ * after calling writepages because some filesystems may redirty the
+ * inode during writepages due to delalloc. It also needs to be done
+ * after handling timestamp expiration, as that may dirty the inode too.
*/
spin_lock(&inode->i_lock);
dirty = inode->i_state & I_DIRTY;
@@ -1524,12 +1531,13 @@
}
/*
- * Write out an inode's dirty pages. Either the caller has an active reference
- * on the inode or the inode has I_WILL_FREE set.
+ * Write out an inode's dirty data and metadata on-demand, i.e. separately from
+ * the regular batched writeback done by the flusher threads in
+ * writeback_sb_inodes(). @wbc controls various aspects of the write, such as
+ * whether it is a data-integrity sync (%WB_SYNC_ALL) or not (%WB_SYNC_NONE).
*
- * This function is designed to be called for writing back one inode which
- * we go e.g. from filesystem. Flusher thread uses __writeback_single_inode()
- * and does more profound writeback list handling in writeback_sb_inodes().
+ * To prevent the inode from going away, either the caller must have a reference
+ * to the inode, or the inode must have I_WILL_FREE or I_FREEING set.
*/
static int writeback_single_inode(struct inode *inode,
struct writeback_control *wbc)
@@ -1544,23 +1552,23 @@
WARN_ON(inode->i_state & I_WILL_FREE);
if (inode->i_state & I_SYNC) {
+ /*
+ * Writeback is already running on the inode. For WB_SYNC_NONE,
+ * that's enough and we can just return. For WB_SYNC_ALL, we
+ * must wait for the existing writeback to complete, then do
+ * writeback again if there's anything left.
+ */
if (wbc->sync_mode != WB_SYNC_ALL)
goto out;
- /*
- * It's a data-integrity sync. We must wait. Since callers hold
- * inode reference or inode has I_WILL_FREE set, it cannot go
- * away under us.
- */
__inode_wait_for_writeback(inode);
}
WARN_ON(inode->i_state & I_SYNC);
/*
- * Skip inode if it is clean and we have no outstanding writeback in
- * WB_SYNC_ALL mode. We don't want to mess with writeback lists in this
- * function since flusher thread may be doing for example sync in
- * parallel and if we move the inode, it could get skipped. So here we
- * make sure inode is on some writeback list and leave it there unless
- * we have completely cleaned the inode.
+ * If the inode is already fully clean, then there's nothing to do.
+ *
+ * For data-integrity syncs we also need to check whether any pages are
+ * still under writeback, e.g. due to prior WB_SYNC_NONE writeback. If
+ * there are any such pages, we'll need to wait for them.
*/
if (!(inode->i_state & I_DIRTY_ALL) &&
(wbc->sync_mode != WB_SYNC_ALL ||
@@ -1576,8 +1584,9 @@
wb = inode_to_wb_and_lock_list(inode);
spin_lock(&inode->i_lock);
/*
- * If inode is clean, remove it from writeback lists. Otherwise don't
- * touch it. See comment above for explanation.
+ * If the inode is now fully clean, then it can be safely removed from
+ * its writeback list (if any). Otherwise the flusher threads are
+ * responsible for the writeback lists.
*/
if (!(inode->i_state & I_DIRTY_ALL))
inode_io_list_del_locked(inode, wb);
@@ -2219,23 +2228,24 @@
}
/**
- * __mark_inode_dirty - internal function
+ * __mark_inode_dirty - internal function to mark an inode dirty
*
* @inode: inode to mark
- * @flags: what kind of dirty (i.e. I_DIRTY_SYNC)
+ * @flags: what kind of dirty, e.g. I_DIRTY_SYNC. This can be a combination of
+ * multiple I_DIRTY_* flags, except that I_DIRTY_TIME can't be combined
+ * with I_DIRTY_PAGES.
*
- * Mark an inode as dirty. Callers should use mark_inode_dirty or
- * mark_inode_dirty_sync.
+ * Mark an inode as dirty. We notify the filesystem, then update the inode's
+ * dirty flags. Then, if needed we add the inode to the appropriate dirty list.
*
- * Put the inode on the super block's dirty list.
+ * Most callers should use mark_inode_dirty() or mark_inode_dirty_sync()
+ * instead of calling this directly.
*
- * CAREFUL! We mark it dirty unconditionally, but move it onto the
- * dirty list only if it is hashed or if it refers to a blockdev.
- * If it was not hashed, it will never be added to the dirty list
- * even if it is later hashed, as it will have been marked dirty already.
+ * CAREFUL! We only add the inode to the dirty list if it is hashed or if it
+ * refers to a blockdev. Unhashed inodes will never be added to the dirty list
+ * even if they are later hashed, as they will have been marked dirty already.
*
- * In short, make sure you hash any inodes _before_ you start marking
- * them dirty.
+ * In short, ensure you hash any inodes _before_ you start marking them dirty.
*
* Note that for blockdevs, inode->dirtied_when represents the dirtying time of
* the block-special inode (/dev/hda1) itself. And the ->dirtied_when field of
@@ -2247,25 +2257,34 @@
void __mark_inode_dirty(struct inode *inode, int flags)
{
struct super_block *sb = inode->i_sb;
- int dirtytime;
+ int dirtytime = 0;
trace_writeback_mark_inode_dirty(inode, flags);
- /*
- * Don't do this for I_DIRTY_PAGES - that doesn't actually
- * dirty the inode itself
- */
- if (flags & (I_DIRTY_INODE | I_DIRTY_TIME)) {
+ if (flags & I_DIRTY_INODE) {
+ /*
+ * Notify the filesystem about the inode being dirtied, so that
+ * (if needed) it can update on-disk fields and journal the
+ * inode. This is only needed when the inode itself is being
+ * dirtied now. I.e. it's only needed for I_DIRTY_INODE, not
+ * for just I_DIRTY_PAGES or I_DIRTY_TIME.
+ */
trace_writeback_dirty_inode_start(inode, flags);
-
if (sb->s_op->dirty_inode)
- sb->s_op->dirty_inode(inode, flags);
-
+ sb->s_op->dirty_inode(inode, flags & I_DIRTY_INODE);
trace_writeback_dirty_inode(inode, flags);
- }
- if (flags & I_DIRTY_INODE)
+
+ /* I_DIRTY_INODE supersedes I_DIRTY_TIME. */
flags &= ~I_DIRTY_TIME;
- dirtytime = flags & I_DIRTY_TIME;
+ } else {
+ /*
+ * Else it's either I_DIRTY_PAGES, I_DIRTY_TIME, or nothing.
+ * (We don't support setting both I_DIRTY_PAGES and I_DIRTY_TIME
+ * in one call to __mark_inode_dirty().)
+ */
+ dirtytime = flags & I_DIRTY_TIME;
+ WARN_ON_ONCE(dirtytime && flags != I_DIRTY_TIME);
+ }
/*
* Paired with smp_mb() in __writeback_single_inode() for the
@@ -2288,6 +2307,7 @@
inode_attach_wb(inode, NULL);
+ /* I_DIRTY_INODE supersedes I_DIRTY_TIME. */
if (flags & I_DIRTY_INODE)
inode->i_state &= ~I_DIRTY_TIME;
inode->i_state |= flags;
diff --git a/fs/gfs2/file.c b/fs/gfs2/file.c
index 89609c2..07f49e5 100644
--- a/fs/gfs2/file.c
+++ b/fs/gfs2/file.c
@@ -749,7 +749,7 @@
{
struct address_space *mapping = file->f_mapping;
struct inode *inode = mapping->host;
- int sync_state = inode->i_state & I_DIRTY_ALL;
+ int sync_state = inode->i_state & I_DIRTY;
struct gfs2_inode *ip = GFS2_I(inode);
int ret = 0, ret1 = 0;
@@ -762,7 +762,7 @@
if (!gfs2_is_jdata(ip))
sync_state &= ~I_DIRTY_PAGES;
if (datasync)
- sync_state &= ~(I_DIRTY_SYNC | I_DIRTY_TIME);
+ sync_state &= ~I_DIRTY_SYNC;
if (sync_state) {
ret = sync_inode_metadata(inode, 1);
diff --git a/fs/gfs2/super.c b/fs/gfs2/super.c
index 2f56acc..042b942 100644
--- a/fs/gfs2/super.c
+++ b/fs/gfs2/super.c
@@ -562,8 +562,6 @@
int need_endtrans = 0;
int ret;
- if (!(flags & I_DIRTY_INODE))
- return;
if (unlikely(gfs2_withdrawn(sdp)))
return;
if (!gfs2_glock_is_locked_by_me(ip->i_gl)) {
diff --git a/fs/inode.c b/fs/inode.c
index 1dc9e03..8742421 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -1743,24 +1743,26 @@
int generic_update_time(struct inode *inode, struct timespec64 *time, int flags)
{
- int iflags = I_DIRTY_TIME;
- bool dirty = false;
+ int dirty_flags = 0;
- if (flags & S_ATIME)
- inode->i_atime = *time;
- if (flags & S_VERSION)
- dirty = inode_maybe_inc_iversion(inode, false);
- if (flags & S_CTIME)
- inode->i_ctime = *time;
- if (flags & S_MTIME)
- inode->i_mtime = *time;
- if ((flags & (S_ATIME | S_CTIME | S_MTIME)) &&
- !(inode->i_sb->s_flags & SB_LAZYTIME))
- dirty = true;
+ if (flags & (S_ATIME | S_CTIME | S_MTIME)) {
+ if (flags & S_ATIME)
+ inode->i_atime = *time;
+ if (flags & S_CTIME)
+ inode->i_ctime = *time;
+ if (flags & S_MTIME)
+ inode->i_mtime = *time;
- if (dirty)
- iflags |= I_DIRTY_SYNC;
- __mark_inode_dirty(inode, iflags);
+ if (inode->i_sb->s_flags & SB_LAZYTIME)
+ dirty_flags |= I_DIRTY_TIME;
+ else
+ dirty_flags |= I_DIRTY_SYNC;
+ }
+
+ if ((flags & S_VERSION) && inode_maybe_inc_iversion(inode, false))
+ dirty_flags |= I_DIRTY_SYNC;
+
+ __mark_inode_dirty(inode, dirty_flags);
return 0;
}
EXPORT_SYMBOL(generic_update_time);
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 6d8b1e7..43ba79d 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -2084,8 +2084,8 @@
/*
* Inode state bits. Protected by inode->i_lock
*
- * Three bits determine the dirty state of the inode, I_DIRTY_SYNC,
- * I_DIRTY_DATASYNC and I_DIRTY_PAGES.
+ * Four bits determine the dirty state of the inode: I_DIRTY_SYNC,
+ * I_DIRTY_DATASYNC, I_DIRTY_PAGES, and I_DIRTY_TIME.
*
* Four bits define the lifetime of an inode. Initially, inodes are I_NEW,
* until that flag is cleared. I_WILL_FREE, I_FREEING and I_CLEAR are set at
@@ -2094,12 +2094,20 @@
* Two bits are used for locking and completion notification, I_NEW and I_SYNC.
*
* I_DIRTY_SYNC Inode is dirty, but doesn't have to be written on
- * fdatasync(). i_atime is the usual cause.
- * I_DIRTY_DATASYNC Data-related inode changes pending. We keep track of
+ * fdatasync() (unless I_DIRTY_DATASYNC is also set).
+ * Timestamp updates are the usual cause.
+ * I_DIRTY_DATASYNC Data-related inode changes pending. We keep track of
* these changes separately from I_DIRTY_SYNC so that we
* don't have to write inode on fdatasync() when only
- * mtime has changed in it.
+ * e.g. the timestamps have changed.
* I_DIRTY_PAGES Inode has dirty pages. Inode itself may be clean.
+ * I_DIRTY_TIME The inode itself only has dirty timestamps, and the
+ * lazytime mount option is enabled. We keep track of this
+ * separately from I_DIRTY_SYNC in order to implement
+ * lazytime. This gets cleared if I_DIRTY_INODE
+ * (I_DIRTY_SYNC and/or I_DIRTY_DATASYNC) gets set. I.e.
+ * either I_DIRTY_TIME *or* I_DIRTY_INODE can be set in
+ * i_state, but not both. I_DIRTY_PAGES may still be set.
* I_NEW Serves as both a mutex and completion notification.
* New inodes set I_NEW. If two processes both create
* the same inode, one of them will release its inode and
@@ -2186,6 +2194,21 @@
__mark_inode_dirty(inode, I_DIRTY_SYNC);
}
+/*
+ * Returns true if the given inode itself only has dirty timestamps (its pages
+ * may still be dirty) and isn't currently being allocated or freed.
+ * Filesystems should call this if when writing an inode when lazytime is
+ * enabled, they want to opportunistically write the timestamps of other inodes
+ * located very nearby on-disk, e.g. in the same inode block. This returns true
+ * if the given inode is in need of such an opportunistic update. Requires
+ * i_lock, or at least later re-checking under i_lock.
+ */
+static inline bool inode_is_dirtytime_only(struct inode *inode)
+{
+ return (inode->i_state & (I_DIRTY_TIME | I_NEW |
+ I_FREEING | I_WILL_FREE)) == I_DIRTY_TIME;
+}
+
extern void inc_nlink(struct inode *inode);
extern void drop_nlink(struct inode *inode);
extern void clear_nlink(struct inode *inode);
