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Message-ID: <20090117022957.20425.52953.stgit@crlf.corp.google.com>
Date: Fri, 16 Jan 2009 18:29:57 -0800
From: Mike Waychison <mikew@...gle.com>
To: linux-kernel@...r.kernel.org, linux-fsdevel@...r.kernel.org
Subject: [PATCH v1 4/8] Fixing iput() called from put_super path
Delaying iput introduces a problem when it comes to unmounting. The problem
lies in fs-specific put_super callbacks that will issue iput()s and assume that
the iputs on their final inodes (for metadata inodes and the like) which causes
problems with deferred iput() as the super_block may go away before the inodes
are finalized.
This patch goes and marks all inodes in a super_block whenever we see that the
inodes are being invalidated with S_SYNCIPUT, which causes us to shortcircuit
the deferred iput and perform a synchronous iput.
Signed-off-by: Mike Waychison <mikew@...gle.com>
---
fs/block_dev.c | 2 +-
fs/ext2/super.c | 2 +-
fs/gfs2/glock.c | 2 +-
fs/gfs2/ops_fstype.c | 2 +-
fs/inode.c | 19 ++++++++++++++-----
fs/ntfs/super.c | 2 +-
fs/smbfs/inode.c | 2 +-
fs/super.c | 4 ++--
include/linux/fs.h | 3 ++-
9 files changed, 24 insertions(+), 14 deletions(-)
diff --git a/fs/block_dev.c b/fs/block_dev.c
index b3c1eff..eb6517e 100644
--- a/fs/block_dev.c
+++ b/fs/block_dev.c
@@ -1400,7 +1400,7 @@ int __invalidate_device(struct block_device *bdev)
* hold).
*/
shrink_dcache_sb(sb);
- res = invalidate_inodes(sb);
+ res = invalidate_inodes(sb, 1);
drop_super(sb);
}
invalidate_bdev(bdev);
diff --git a/fs/ext2/super.c b/fs/ext2/super.c
index da8bdea..190dfc9 100644
--- a/fs/ext2/super.c
+++ b/fs/ext2/super.c
@@ -1185,7 +1185,7 @@ static int ext2_remount (struct super_block * sb, int * flags, char * data)
es = sbi->s_es;
if (((sbi->s_mount_opt & EXT2_MOUNT_XIP) !=
(old_mount_opt & EXT2_MOUNT_XIP)) &&
- invalidate_inodes(sb))
+ invalidate_inodes(sb, 0))
ext2_warning(sb, __func__, "busy inodes while remounting "\
"xip remain in cache (no functional problem)");
if ((*flags & MS_RDONLY) == (sb->s_flags & MS_RDONLY))
diff --git a/fs/gfs2/glock.c b/fs/gfs2/glock.c
index 6b983ae..4d95373 100644
--- a/fs/gfs2/glock.c
+++ b/fs/gfs2/glock.c
@@ -1574,7 +1574,7 @@ void gfs2_gl_hash_clear(struct gfs2_sbd *sdp)
}
down_write(&gfs2_umount_flush_sem);
- invalidate_inodes(sdp->sd_vfs);
+ invalidate_inodes(sdp->sd_vfs, 1);
up_write(&gfs2_umount_flush_sem);
msleep(10);
}
diff --git a/fs/gfs2/ops_fstype.c b/fs/gfs2/ops_fstype.c
index f91eebd..5099ca5 100644
--- a/fs/gfs2/ops_fstype.c
+++ b/fs/gfs2/ops_fstype.c
@@ -1205,7 +1205,7 @@ fail_locking:
fail_lm:
gfs2_gl_hash_clear(sdp);
gfs2_lm_unmount(sdp);
- while (invalidate_inodes(sb))
+ while (invalidate_inodes(sb, 1))
yield();
fail_sys:
gfs2_sys_fs_del(sdp);
diff --git a/fs/inode.c b/fs/inode.c
index 56cf6e2..9aa574d 100644
--- a/fs/inode.c
+++ b/fs/inode.c
@@ -335,7 +335,8 @@ static void dispose_list(struct list_head *head)
/*
* Invalidate all inodes for a device.
*/
-static int invalidate_list(struct list_head *head, struct list_head *dispose)
+static int invalidate_list(struct list_head *head, struct list_head *dispose,
+ int umount)
{
struct list_head *next;
int busy = 0, count = 0;
@@ -358,6 +359,8 @@ static int invalidate_list(struct list_head *head, struct list_head *dispose)
break;
inode = list_entry(tmp, struct inode, i_sb_list);
invalidate_inode_buffers(inode);
+ if (umount)
+ inode->i_flags |= S_SYNCIPUT;
if (!atomic_read(&inode->i_count)) {
list_move(&inode->i_list, dispose);
inode->i_state |= I_FREEING;
@@ -374,12 +377,13 @@ static int invalidate_list(struct list_head *head, struct list_head *dispose)
/**
* invalidate_inodes - discard the inodes on a device
* @sb: superblock
+ * @umount: are we unmounting?
*
* Discard all of the inodes for a given superblock. If the discard
* fails because there are busy inodes then a non zero value is returned.
* If the discard is successful all the inodes have been discarded.
*/
-int invalidate_inodes(struct super_block * sb)
+int invalidate_inodes(struct super_block *sb, int umount)
{
int busy;
LIST_HEAD(throw_away);
@@ -394,7 +398,7 @@ int invalidate_inodes(struct super_block * sb)
spin_lock(&inode_lock);
inotify_unmount_inodes(&sb->s_inodes);
- busy = invalidate_list(&sb->s_inodes, &throw_away);
+ busy = invalidate_list(&sb->s_inodes, &throw_away, umount);
spin_unlock(&inode_lock);
dispose_list(&throw_away);
@@ -1372,8 +1376,12 @@ void iput(struct inode *inode)
if (inode) {
BUG_ON(inode->i_state == I_CLEAR);
- if (!atomic_add_unless(&inode->i_count, -1, 1))
- postpone_iput(inode);
+ if (!(inode->i_flags & S_SYNCIPUT)) {
+ if (!atomic_add_unless(&inode->i_count, -1, 1))
+ postpone_iput(inode);
+ } else {
+ real_iput(inode);
+ }
}
}
@@ -1663,6 +1671,7 @@ static void iput_drain_per_cpu_cb(struct work_struct *dummy)
void iput_drain_all(void)
{
+ /* TODO: error checking? */
schedule_on_each_cpu(iput_drain_per_cpu_cb);
}
diff --git a/fs/ntfs/super.c b/fs/ntfs/super.c
index 4a46743..04220f3 100644
--- a/fs/ntfs/super.c
+++ b/fs/ntfs/super.c
@@ -3051,7 +3051,7 @@ iput_tmp_ino_err_out_now:
* method again... FIXME: Do we need to do this twice now because of
* attribute inodes? I think not, so leave as is for now... (AIA)
*/
- if (invalidate_inodes(sb)) {
+ if (invalidate_inodes(sb, 1)) {
ntfs_error(sb, "Busy inodes left. This is most likely a NTFS "
"driver bug.");
/* Copied from fs/super.c. I just love this message. (-; */
diff --git a/fs/smbfs/inode.c b/fs/smbfs/inode.c
index fc27fbf..4def57a 100644
--- a/fs/smbfs/inode.c
+++ b/fs/smbfs/inode.c
@@ -229,7 +229,7 @@ smb_invalidate_inodes(struct smb_sb_info *server)
{
VERBOSE("\n");
shrink_dcache_sb(SB_of(server));
- invalidate_inodes(SB_of(server));
+ invalidate_inodes(SB_of(server), 1);
}
/*
diff --git a/fs/super.c b/fs/super.c
index 534840f..244b6f5 100644
--- a/fs/super.c
+++ b/fs/super.c
@@ -306,7 +306,7 @@ void generic_shutdown_super(struct super_block *sb)
async_synchronize_full_special(&sb->s_async_list);
/* bad name - it should be evict_inodes() */
- invalidate_inodes(sb);
+ invalidate_inodes(sb, 1);
lock_kernel();
if (sop->write_super && sb->s_dirt)
@@ -315,7 +315,7 @@ void generic_shutdown_super(struct super_block *sb)
sop->put_super(sb);
/* Forget any remaining inodes */
- if (invalidate_inodes(sb)) {
+ if (invalidate_inodes(sb, 1)) {
printk("VFS: Busy inodes after unmount of %s. "
"Self-destruct in 5 seconds. Have a nice day...\n",
sb->s_id);
diff --git a/include/linux/fs.h b/include/linux/fs.h
index 47eaa71..aa90620 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -161,6 +161,7 @@ struct inodes_stat_t {
#define S_NOCMTIME 128 /* Do not update file c/mtime */
#define S_SWAPFILE 256 /* Do not truncate: swapon got its bmaps */
#define S_PRIVATE 512 /* Inode is fs-internal */
+#define S_SYNCIPUT 1024 /* Filesystem going down, use sync iput() */
/*
* Note that nosuid etc flags are inode-specific: setting some file-system
@@ -1805,7 +1806,7 @@ extern int check_disk_change(struct block_device *);
extern int __invalidate_device(struct block_device *);
extern int invalidate_partition(struct gendisk *, int);
#endif
-extern int invalidate_inodes(struct super_block *);
+extern int invalidate_inodes(struct super_block *, int umount);
unsigned long __invalidate_mapping_pages(struct address_space *mapping,
pgoff_t start, pgoff_t end,
bool be_atomic);
--
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