[PATCHSET 0/7] exofs: Some pending changes for 2.6.39

[PATCHSET 0/7] exofs: Some pending changes for 2.6.39

[Boaz Harrosh]

Submitted for review a few patches for the next Merge window.

List of patches:

[PATCH 1/7] exofs: Trivial: fix some indentation and debug prints
[PATCH 2/7] exofs: Optimize read_4_write

[PATCH 3/7] exofs: simple fsync race fix
	Nick please re-review your patch. I think it is needed.
	I ran with it for a while now. It makes perfect sense.

[PATCH 4/7] exofs: Override read-ahead to align on stripe_size
	Thanks to Chris Mason and Marc Dionne. This patch is a nice
	bonus for the kind of striping done in exofs.

[PATCH 5/7] exofs: Add option to mount by osdname
	A long over do on this simple option

[PATCH 6/7] exofs: Write sbi->s_nextid as part of the Create command
[PATCH 7/7] exofs: deprecate the commands pending counter

Thanks
Boaz

[PATCH 1/7] exofs: trivial: fix some indentation and debug prints

[Boaz Harrosh]

I stumbled on some of these prints in log files so, might
just submit the fixes.

Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
---
 fs/exofs/dir.c |   15 ++++++---------
 1 files changed, 6 insertions(+), 9 deletions(-)

diff --git a/fs/exofs/dir.c b/fs/exofs/dir.c
index dcc941d..132721a 100644
--- a/fs/exofs/dir.c
+++ b/fs/exofs/dir.c
@@ -261,9 +261,7 @@ exofs_readdir(struct file *filp, void *dirent, filldir_t filldir)
 		struct page *page = exofs_get_page(inode, n);
 
 		if (IS_ERR(page)) {
-			EXOFS_ERR("ERROR: "
-				   "bad page in #%lu",
-				   inode->i_ino);
+			EXOFS_ERR("ERROR: bad page in #%lu", inode->i_ino);
 			filp->f_pos += PAGE_CACHE_SIZE - offset;
 			return PTR_ERR(page);
 		}
@@ -282,8 +280,7 @@ exofs_readdir(struct file *filp, void *dirent, filldir_t filldir)
 							EXOFS_DIR_REC_LEN(1);
 		for (; (char *)de <= limit; de = exofs_next_entry(de)) {
 			if (de->rec_len == 0) {
-				EXOFS_ERR("ERROR: "
-					"zero-length directory entry");
+				EXOFS_ERR("ERROR: zero-length directory entry");
 				exofs_put_page(page);
 				return -EIO;
 			}
@@ -342,9 +339,8 @@ struct exofs_dir_entry *exofs_find_entry(struct inode *dir,
 			kaddr += exofs_last_byte(dir, n) - reclen;
 			while ((char *) de <= kaddr) {
 				if (de->rec_len == 0) {
-					EXOFS_ERR(
-						"ERROR: exofs_find_entry: "
-						"zero-length directory entry");
+					EXOFS_ERR("ERROR: exofs_find_entry: "
+						 "zero-length directory entry");
 					exofs_put_page(page);
 					goto out;
 				}
@@ -491,7 +487,8 @@ int exofs_add_link(struct dentry *dentry, struct inode *inode)
 		exofs_put_page(page);
 	}
 
-	EXOFS_ERR("exofs_add_link: BAD dentry=%p or inode=%p", dentry, inode);
+	EXOFS_ERR("exofs_add_link: BAD dentry=%p or inode=%lu",
+		  dentry, inode->i_ino);
 	return -EINVAL;
 
 got_it:
-- 
1.7.2.3

[PATCH 2/7] exofs: Optimize read_4_write

[Boaz Harrosh]

Don't attempt a read passed i_size, just zero the page and be
done with it.

Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
---
 fs/exofs/inode.c |   23 ++++++++++++++++++++---
 1 files changed, 20 insertions(+), 3 deletions(-)

diff --git a/fs/exofs/inode.c b/fs/exofs/inode.c
index a755523..7d755dc 100644
--- a/fs/exofs/inode.c
+++ b/fs/exofs/inode.c
@@ -350,8 +350,10 @@ static int readpage_strip(void *data, struct page *page)
 
 		if (!pcol->read_4_write)
 			unlock_page(page);
-		EXOFS_DBGMSG("readpage_strip(0x%lx, 0x%lx) empty page,"
-			     " splitting\n", inode->i_ino, page->index);
+		EXOFS_DBGMSG("readpage_strip(0x%lx) empty page len=%zx "
+			     "read_4_write=%d index=0x%lx end_index=0x%lx "
+			     "splitting\n", inode->i_ino, len,
+			     pcol->read_4_write, page->index, end_index);
 		return read_exec(pcol);
 	}
 
@@ -722,11 +724,28 @@ int exofs_write_begin(struct file *file, struct address_space *mapping,
 
 	 /* read modify write */
 	if (!PageUptodate(page) && (len != PAGE_CACHE_SIZE)) {
+		loff_t i_size = i_size_read(mapping->host);
+		pgoff_t end_index = i_size >> PAGE_CACHE_SHIFT;
+		size_t rlen;
+
+		if (page->index < end_index)
+			rlen = PAGE_CACHE_SIZE;
+		else if (page->index == end_index)
+			rlen = i_size & ~PAGE_CACHE_MASK;
+		else
+			rlen = 0;
+
+		if (!rlen) {
+			clear_highpage(page);
+			SetPageUptodate(page);
+			goto out;
+		}
+
 		ret = _readpage(page, true);
 		if (ret) {
 			/*SetPageError was done by _readpage. Is it ok?*/
 			unlock_page(page);
-			EXOFS_DBGMSG("__readpage_filler failed\n");
+			EXOFS_DBGMSG("__readpage failed\n");
 		}
 	}
 out:

[PATCH 3/7] exofs: simple fsync race fix

[Boaz Harrosh]

From: Nick Piggin <npiggin@kernel.dk>

It is incorrect to test inode dirty bits without participating in the inode
writeback protocol. Inode writeback sets I_SYNC and clears I_DIRTY_?, then
writes out the particular bits, then clears I_SYNC when it is done. BTW. it
may not completely write all pages out, so I_DIRTY_PAGES would get set
again.

This is a standard pattern used throughout the kernel's writeback caches
(I_SYNC ~= I_WRITEBACK, if that makes it clearer).

And so it is not possible to determine an inode's dirty status just by
checking I_DIRTY bits. Especially not for the purpose of data integrity
syncs.

Missing the check for these bits means that fsync can complete while
writeback to the inode is underway. Inode writeback functions get this
right, so call into them rather than try to shortcut things by testing
dirty state improperly.

Signed-off-by: Nick Piggin <npiggin@kernel.dk>
Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
---
 fs/exofs/file.c  |    5 -----
 fs/exofs/inode.c |    3 ++-
 2 files changed, 2 insertions(+), 6 deletions(-)

diff --git a/fs/exofs/file.c b/fs/exofs/file.c
index b905c79..4c0d6ba 100644
--- a/fs/exofs/file.c
+++ b/fs/exofs/file.c
@@ -48,11 +48,6 @@ static int exofs_file_fsync(struct file *filp, int datasync)
 	struct inode *inode = filp->f_mapping->host;
 	struct super_block *sb;
 
-	if (!(inode->i_state & I_DIRTY))
-		return 0;
-	if (datasync && !(inode->i_state & I_DIRTY_DATASYNC))
-		return 0;
-
 	ret = sync_inode_metadata(inode, 1);
 
 	/* This is a good place to write the sb */
diff --git a/fs/exofs/inode.c b/fs/exofs/inode.c
index 7d755dc..c719b34 100644
--- a/fs/exofs/inode.c
+++ b/fs/exofs/inode.c
@@ -1288,7 +1288,8 @@ out:
 
 int exofs_write_inode(struct inode *inode, struct writeback_control *wbc)
 {
-	return exofs_update_inode(inode, wbc->sync_mode == WB_SYNC_ALL);
+	/* FIXME: fix fsync and use wbc->sync_mode == WB_SYNC_ALL */
+	return exofs_update_inode(inode, 1);
 }
 
 /*
-- 
1.7.2.3

[PATCH 4/7] exofs: Override read-ahead to align on stripe_size

[Boaz Harrosh]

* Set all inode->i_mapping->backing_dev_info to point to
  the per super-block sb->s_bdi.

* Calculating a read_ahead that is:
  - preferable 2 stripes long
    (Future patch will add a mount option to override this)
  - Minimum 128K aligned up to stripe-size
  - Caped to maximum-IO-sizes round down to stripe_size.
    (Max sizes are governed by max bio-size that fits in a page
     times number-of-devices)

CC: Marc Dionne <marc.c.dionne@gmail.com>
Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
---
 fs/exofs/exofs.h |    2 ++
 fs/exofs/inode.c |   19 +++++++++++++++----
 fs/exofs/super.c |   18 ++++++++++++++++++
 3 files changed, 35 insertions(+), 4 deletions(-)

diff --git a/fs/exofs/exofs.h b/fs/exofs/exofs.h
index 2dc925f..99fcb91 100644
--- a/fs/exofs/exofs.h
+++ b/fs/exofs/exofs.h
@@ -256,6 +256,8 @@ static inline int exofs_oi_read(struct exofs_i_info *oi,
 }
 
 /* inode.c               */
+unsigned exofs_max_io_pages(struct exofs_layout *layout,
+			    unsigned expected_pages);
 int exofs_setattr(struct dentry *, struct iattr *);
 int exofs_write_begin(struct file *file, struct address_space *mapping,
 		loff_t pos, unsigned len, unsigned flags,
diff --git a/fs/exofs/inode.c b/fs/exofs/inode.c
index c719b34..7f36e28 100644
--- a/fs/exofs/inode.c
+++ b/fs/exofs/inode.c
@@ -43,6 +43,17 @@ enum { BIO_MAX_PAGES_KMALLOC =
 		PAGE_SIZE / sizeof(struct page *),
 };
 
+unsigned exofs_max_io_pages(struct exofs_layout *layout,
+			    unsigned expected_pages)
+{
+	unsigned pages = min_t(unsigned, expected_pages, MAX_PAGES_KMALLOC);
+
+	/* TODO: easily support bio chaining */
+	pages =  min_t(unsigned, pages,
+		       layout->group_width * BIO_MAX_PAGES_KMALLOC);
+	return pages;
+}
+
 struct page_collect {
 	struct exofs_sb_info *sbi;
 	struct inode *inode;
@@ -97,8 +108,7 @@ static void _pcol_reset(struct page_collect *pcol)
 
 static int pcol_try_alloc(struct page_collect *pcol)
 {
-	unsigned pages = min_t(unsigned, pcol->expected_pages,
-			  MAX_PAGES_KMALLOC);
+	unsigned pages;
 
 	if (!pcol->ios) { /* First time allocate io_state */
 		int ret = exofs_get_io_state(&pcol->sbi->layout, &pcol->ios);
@@ -108,8 +118,7 @@ static int pcol_try_alloc(struct page_collect *pcol)
 	}
 
 	/* TODO: easily support bio chaining */
-	pages =  min_t(unsigned, pages,
-		       pcol->sbi->layout.group_width * BIO_MAX_PAGES_KMALLOC);
+	pages =  exofs_max_io_pages(&pcol->sbi->layout, pcol->expected_pages);
 
 	for (; pages; pages >>= 1) {
 		pcol->pages = kmalloc(pages * sizeof(struct page *),
@@ -1047,6 +1056,7 @@ struct inode *exofs_iget(struct super_block *sb, unsigned long ino)
 		memcpy(oi->i_data, fcb.i_data, sizeof(fcb.i_data));
 	}
 
+	inode->i_mapping->backing_dev_info = sb->s_bdi;
 	if (S_ISREG(inode->i_mode)) {
 		inode->i_op = &exofs_file_inode_operations;
 		inode->i_fop = &exofs_file_operations;
@@ -1147,6 +1157,7 @@ struct inode *exofs_new_inode(struct inode *dir, int mode)
 
 	sbi = sb->s_fs_info;
 
+	inode->i_mapping->backing_dev_info = sb->s_bdi;
 	sb->s_dirt = 1;
 	inode_init_owner(inode, dir, mode);
 	inode->i_ino = sbi->s_nextid++;
diff --git a/fs/exofs/super.c b/fs/exofs/super.c
index 78f5ad6..e87510f 100644
--- a/fs/exofs/super.c
+++ b/fs/exofs/super.c
@@ -390,6 +390,23 @@ static int _read_and_match_data_map(struct exofs_sb_info *sbi, unsigned numdevs,
 	return 0;
 }
 
+static unsigned __ra_pages(struct exofs_layout *layout)
+{
+	const unsigned _MIN_RA = 32; /* min 128K read-ahead */
+	unsigned ra_pages = layout->group_width * layout->stripe_unit /
+				PAGE_SIZE;
+	unsigned max_io_pages = exofs_max_io_pages(layout, ~0);
+
+	ra_pages *= 2; /* two stripes */
+	if (ra_pages < _MIN_RA)
+		ra_pages = roundup(_MIN_RA, ra_pages / 2);
+
+	if (ra_pages > max_io_pages)
+		ra_pages = max_io_pages;
+
+	return ra_pages;
+}
+
 /* @odi is valid only as long as @fscb_dev is valid */
 static int exofs_devs_2_odi(struct exofs_dt_device_info *dt_dev,
 			     struct osd_dev_info *odi)
@@ -623,6 +640,7 @@ static int exofs_fill_super(struct super_block *sb, void *data, int silent)
 	}
 
 	/* set up operation vectors */
+	sbi->bdi.ra_pages = __ra_pages(&sbi->layout);
 	sb->s_bdi = &sbi->bdi;
 	sb->s_fs_info = sbi;
 	sb->s_op = &exofs_sops;
-- 
1.7.2.3

[PATCH 5/7] exofs: Add option to mount by osdname

[Boaz Harrosh]

If /dev/osd* devices are shuffled because more devices
where added, and/or login order has changed. It is hard to
mount the FS you want.

Add an option to mount by osdname. osdname is any osd-device's
osdname as specified to the mkfs.exofs command when formatting
the osd-devices.
The new mount format is:
	OPT="osdname=$UUID0,pid=$PID,_netdev"
	mount -t exofs -o $OPT $DEV_OSD0 $MOUNTDIR

if "osdname=" is specified in options above $DEV_OSD0 is
ignored and can be empty.

Also while at it: Removed some old unused Opt_* enumes.

Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
---
 Documentation/filesystems/exofs.txt |   10 +++++++++-
 fs/exofs/super.c                    |   31 +++++++++++++++++++++++++++----
 2 files changed, 36 insertions(+), 5 deletions(-)

diff --git a/Documentation/filesystems/exofs.txt b/Documentation/filesystems/exofs.txt
index abd2a9b..23583a1 100644
--- a/Documentation/filesystems/exofs.txt
+++ b/Documentation/filesystems/exofs.txt
@@ -104,7 +104,15 @@ Where:
     exofs specific options: Options are separated by commas (,)
 		pid=<integer> - The partition number to mount/create as
                                 container of the filesystem.
-                                This option is mandatory.
+                                This option is mandatory. integer can be
+                                Hex by pre-pending an 0x to the number.
+		osdname=<id>  - Mount by a device's osdname.
+                                osdname is usually a 36 character uuid of the
+                                form "d2683732-c906-4ee1-9dbd-c10c27bb40df".
+                                It is one of the device's uuid specified in the
+                                mkfs.exofs format command.
+                                If this option is specified then the /dev/osdX
+                                above can be empty and is ignored.
                 to=<integer>  - Timeout in ticks for a single command.
                                 default is (60 * HZ) [for debugging only]
 
diff --git a/fs/exofs/super.c b/fs/exofs/super.c
index e87510f..474989e 100644
--- a/fs/exofs/super.c
+++ b/fs/exofs/super.c
@@ -48,6 +48,7 @@
  * struct to hold what we get from mount options
  */
 struct exofs_mountopt {
+	bool is_osdname;
 	const char *dev_name;
 	uint64_t pid;
 	int timeout;
@@ -56,7 +57,7 @@ struct exofs_mountopt {
 /*
  * exofs-specific mount-time options.
  */
-enum { Opt_pid, Opt_to, Opt_mkfs, Opt_format, Opt_err };
+enum { Opt_name, Opt_pid, Opt_to, Opt_err };
 
 /*
  * Our mount-time options.  These should ideally be 64-bit unsigned, but the
@@ -64,6 +65,7 @@ enum { Opt_pid, Opt_to, Opt_mkfs, Opt_format, Opt_err };
  * sufficient for most applications now.
  */
 static match_table_t tokens = {
+	{Opt_name, "osdname=%s"},
 	{Opt_pid, "pid=%u"},
 	{Opt_to, "to=%u"},
 	{Opt_err, NULL}
@@ -94,6 +96,14 @@ static int parse_options(char *options, struct exofs_mountopt *opts)
 
 		token = match_token(p, tokens, args);
 		switch (token) {
+		case Opt_name:
+			opts->dev_name = match_strdup(&args[0]);
+			if (unlikely(!opts->dev_name)) {
+				EXOFS_ERR("Error allocating dev_name");
+				return -ENOMEM;
+			}
+			opts->is_osdname = true;
+			break;
 		case Opt_pid:
 			if (0 == match_strlcpy(str, &args[0], sizeof(str)))
 				return -EINVAL;
@@ -575,9 +585,17 @@ static int exofs_fill_super(struct super_block *sb, void *data, int silent)
 		goto free_bdi;
 
 	/* use mount options to fill superblock */
-	od = osduld_path_lookup(opts->dev_name);
+	if (opts->is_osdname) {
+		struct osd_dev_info odi = {.systemid_len = 0};
+
+		odi.osdname_len = strlen(opts->dev_name);
+		odi.osdname = (u8 *)opts->dev_name;
+		od = osduld_info_lookup(&odi);
+	} else {
+		od = osduld_path_lookup(opts->dev_name);
+	}
 	if (IS_ERR(od)) {
-		ret = PTR_ERR(od);
+		ret = -EINVAL;
 		goto free_sbi;
 	}
 
@@ -670,6 +688,8 @@ static int exofs_fill_super(struct super_block *sb, void *data, int silent)
 
 	_exofs_print_device("Mounting", opts->dev_name, sbi->layout.s_ods[0],
 			    sbi->layout.s_pid);
+	if (opts->is_osdname)
+		kfree(opts->dev_name);
 	return 0;
 
 free_sbi:
@@ -678,6 +698,8 @@ free_bdi:
 	EXOFS_ERR("Unable to mount exofs on %s pid=0x%llx err=%d\n",
 		  opts->dev_name, sbi->layout.s_pid, ret);
 	exofs_free_sbi(sbi);
+	if (opts->is_osdname)
+		kfree(opts->dev_name);
 	return ret;
 }
 
@@ -695,7 +717,8 @@ static struct dentry *exofs_mount(struct file_system_type *type,
 	if (ret)
 		return ERR_PTR(ret);
 
-	opts.dev_name = dev_name;
+	if (!opts.dev_name)
+		opts.dev_name = dev_name;
 	return mount_nodev(type, flags, &opts, exofs_fill_super);
 }
 
-- 
1.7.2.3

[PATCH 6/7] exofs: Write sbi->s_nextid as part of the Create command

[Boaz Harrosh]

Before when creating a new inode, we'd set the sb->s_dirt flag,
and sometime later the system would write out s_nextid as part
of the sb_info. Also on inode sync we would force the sb sync
as well.

Define the s_nextid as a new partition attribute and set it
every time we create a new object.
At mount we read it from it's new place.

We now never set sb->s_dirt anywhere in exofs. write_super
is actually never called. The call to exofs_write_super from
exofs_put_super is also removed because the VFS always calls
->sync_fs before calling ->put_super twice.

To stay backward-and-forward compatible we also write the old
s_nextid in the super_block object at unmount, and support zero
length attribute on mount.

This also fixes a BUG where in layouts when group_width was not
a divisor of EXOFS_SUPER_ID (0x10000) the s_nextid was not read
from the device it was written to. Because of the sliding window
layout trick, and because the read was always done from the 0
device but the write was done via the raid engine that might slide
the device view. Now we read and write through the raid engine.

Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
---
 fs/exofs/common.h |   18 ++++++-
 fs/exofs/exofs.h  |    4 +-
 fs/exofs/file.c   |   11 +----
 fs/exofs/inode.c  |    4 +-
 fs/exofs/super.c  |  135 ++++++++++++++++++++++++++++++++++++++++++++++------
 5 files changed, 141 insertions(+), 31 deletions(-)

diff --git a/fs/exofs/common.h b/fs/exofs/common.h
index f0d5203..3961d7d 100644
--- a/fs/exofs/common.h
+++ b/fs/exofs/common.h
@@ -53,10 +53,14 @@
 #define EXOFS_ROOT_ID	0x10002	/* object ID for root directory */
 
 /* exofs Application specific page/attribute */
+/* Inode attrs */
 # define EXOFS_APAGE_FS_DATA	(OSD_APAGE_APP_DEFINED_FIRST + 3)
 # define EXOFS_ATTR_INODE_DATA	1
 # define EXOFS_ATTR_INODE_FILE_LAYOUT	2
 # define EXOFS_ATTR_INODE_DIR_LAYOUT	3
+/* Partition attrs */
+# define EXOFS_APAGE_SB_DATA	(0xF0000000U + 3)
+# define EXOFS_ATTR_SB_STATS	1
 
 /*
  * The maximum number of files we can have is limited by the size of the
@@ -86,8 +90,8 @@ enum {
  */
 enum {EXOFS_FSCB_VER = 1, EXOFS_DT_VER = 1};
 struct exofs_fscb {
-	__le64  s_nextid;	/* Highest object ID used */
-	__le64  s_numfiles;	/* Number of files on fs */
+	__le64  s_nextid;	/* Only used after mkfs */
+	__le64  s_numfiles;	/* Only used after mkfs */
 	__le32	s_version;	/* == EXOFS_FSCB_VER */
 	__le16  s_magic;	/* Magic signature */
 	__le16  s_newfs;	/* Non-zero if this is a new fs */
@@ -98,6 +102,16 @@ struct exofs_fscb {
 } __packed;
 
 /*
+ * This struct is set on the FS partition's attributes.
+ * [EXOFS_APAGE_SB_DATA, EXOFS_ATTR_SB_STATS] and is written together
+ * with the create command, to atomically persist the sb writeable information.
+ */
+struct exofs_sb_stats {
+	__le64  s_nextid;	/* Highest object ID used */
+	__le64  s_numfiles;	/* Number of files on fs */
+} __packed;
+
+/*
  * Describes the raid used in the FS. It is part of the device table.
  * This here is taken from the pNFS-objects definition. In exofs we
  * use one raid policy through-out the filesystem. (NOTE: the funny
diff --git a/fs/exofs/exofs.h b/fs/exofs/exofs.h
index 99fcb91..c965806 100644
--- a/fs/exofs/exofs.h
+++ b/fs/exofs/exofs.h
@@ -77,7 +77,7 @@ struct exofs_layout {
  * our extension to the in-memory superblock
  */
 struct exofs_sb_info {
-	struct exofs_fscb s_fscb;		/* Written often, pre-allocate*/
+	struct exofs_sb_stats s_ess;		/* Written often, pre-allocate*/
 	int		s_timeout;		/* timeout for OSD operations */
 	uint64_t	s_nextid;		/* highest object ID used     */
 	uint32_t	s_numfiles;		/* number of files on fs      */
@@ -281,7 +281,7 @@ int exofs_set_link(struct inode *, struct exofs_dir_entry *, struct page *,
 		    struct inode *);
 
 /* super.c               */
-int exofs_sync_fs(struct super_block *sb, int wait);
+int exofs_sbi_write_stats(struct exofs_sb_info *sbi);
 
 /*********************
  * operation vectors *
diff --git a/fs/exofs/file.c b/fs/exofs/file.c
index 4c0d6ba..45ca323 100644
--- a/fs/exofs/file.c
+++ b/fs/exofs/file.c
@@ -45,17 +45,8 @@ static int exofs_release_file(struct inode *inode, struct file *filp)
 static int exofs_file_fsync(struct file *filp, int datasync)
 {
 	int ret;
-	struct inode *inode = filp->f_mapping->host;
-	struct super_block *sb;
-
-	ret = sync_inode_metadata(inode, 1);
-
-	/* This is a good place to write the sb */
-	/* TODO: Sechedule an sb-sync on create */
-	sb = inode->i_sb;
-	if (sb->s_dirt)
-		exofs_sync_fs(sb, 1);
 
+	ret = sync_inode_metadata(filp->f_mapping->host, 1);
 	return ret;
 }
 
diff --git a/fs/exofs/inode.c b/fs/exofs/inode.c
index 7f36e28..5bd739c 100644
--- a/fs/exofs/inode.c
+++ b/fs/exofs/inode.c
@@ -1100,6 +1100,7 @@ int __exofs_wait_obj_created(struct exofs_i_info *oi)
 	}
 	return unlikely(is_bad_inode(&oi->vfs_inode)) ? -EIO : 0;
 }
+
 /*
  * Callback function from exofs_new_inode().  The important thing is that we
  * set the obj_created flag so that other methods know that the object exists on
@@ -1158,7 +1159,6 @@ struct inode *exofs_new_inode(struct inode *dir, int mode)
 	sbi = sb->s_fs_info;
 
 	inode->i_mapping->backing_dev_info = sb->s_bdi;
-	sb->s_dirt = 1;
 	inode_init_owner(inode, dir, mode);
 	inode->i_ino = sbi->s_nextid++;
 	inode->i_blkbits = EXOFS_BLKSHIFT;
@@ -1169,6 +1169,8 @@ struct inode *exofs_new_inode(struct inode *dir, int mode)
 	spin_unlock(&sbi->s_next_gen_lock);
 	insert_inode_hash(inode);
 
+	exofs_sbi_write_stats(sbi); /* Make sure new sbi->s_nextid is on disk */
+
 	mark_inode_dirty(inode);
 
 	ret = exofs_get_io_state(&sbi->layout, &ios);
diff --git a/fs/exofs/super.c b/fs/exofs/super.c
index 474989e..2fa6df9 100644
--- a/fs/exofs/super.c
+++ b/fs/exofs/super.c
@@ -213,6 +213,101 @@ static void destroy_inodecache(void)
 static const struct super_operations exofs_sops;
 static const struct export_operations exofs_export_ops;
 
+static const struct osd_attr g_attr_sb_stats = ATTR_DEF(
+	EXOFS_APAGE_SB_DATA,
+	EXOFS_ATTR_SB_STATS,
+	sizeof(struct exofs_sb_stats));
+
+static int __sbi_read_stats(struct exofs_sb_info *sbi)
+{
+	struct osd_attr attrs[] = {
+		[0] = g_attr_sb_stats,
+	};
+	struct exofs_io_state *ios;
+	int ret;
+
+	ret = exofs_get_io_state(&sbi->layout, &ios);
+	if (unlikely(ret)) {
+		EXOFS_ERR("%s: exofs_get_io_state failed.\n", __func__);
+		return ret;
+	}
+
+	ios->cred = sbi->s_cred;
+
+	ios->in_attr = attrs;
+	ios->in_attr_len = ARRAY_SIZE(attrs);
+
+	ret = exofs_sbi_read(ios);
+	if (unlikely(ret)) {
+		EXOFS_ERR("Error reading super_block stats => %d\n", ret);
+		goto out;
+	}
+
+	ret = extract_attr_from_ios(ios, &attrs[0]);
+	if (ret) {
+		EXOFS_ERR("%s: extract_attr of sb_stats failed\n", __func__);
+		goto out;
+	}
+	if (attrs[0].len) {
+		struct exofs_sb_stats *ess;
+
+		if (unlikely(attrs[0].len != sizeof(*ess))) {
+			EXOFS_ERR("%s: Wrong version of exofs_sb_stats "
+				  "size(%d) != expected(%zd)\n",
+				  __func__, attrs[0].len, sizeof(*ess));
+			goto out;
+		}
+
+		ess = attrs[0].val_ptr;
+		sbi->s_nextid = le64_to_cpu(ess->s_nextid);
+		sbi->s_numfiles = le32_to_cpu(ess->s_numfiles);
+	}
+
+out:
+	exofs_put_io_state(ios);
+	return ret;
+}
+
+static void stats_done(struct exofs_io_state *ios, void *p)
+{
+	exofs_put_io_state(ios);
+	/* Good thanks nothing to do anymore */
+}
+
+/* Asynchronously write the stats attribute */
+int exofs_sbi_write_stats(struct exofs_sb_info *sbi)
+{
+	struct osd_attr attrs[] = {
+		[0] = g_attr_sb_stats,
+	};
+	struct exofs_io_state *ios;
+	int ret;
+
+	ret = exofs_get_io_state(&sbi->layout, &ios);
+	if (unlikely(ret)) {
+		EXOFS_ERR("%s: exofs_get_io_state failed.\n", __func__);
+		return ret;
+	}
+
+	sbi->s_ess.s_nextid   = cpu_to_le64(sbi->s_nextid);
+	sbi->s_ess.s_numfiles = cpu_to_le64(sbi->s_numfiles);
+	attrs[0].val_ptr = &sbi->s_ess;
+
+	ios->cred = sbi->s_cred;
+	ios->done = stats_done;
+	ios->private = sbi;
+	ios->out_attr = attrs;
+	ios->out_attr_len = ARRAY_SIZE(attrs);
+
+	ret = exofs_sbi_write(ios);
+	if (unlikely(ret)) {
+		EXOFS_ERR("%s: exofs_sbi_write failed.\n", __func__);
+		exofs_put_io_state(ios);
+	}
+
+	return ret;
+}
+
 /*
  * Write the superblock to the OSD
  */
@@ -223,18 +318,25 @@ int exofs_sync_fs(struct super_block *sb, int wait)
 	struct exofs_io_state *ios;
 	int ret = -ENOMEM;
 
-	lock_super(sb);
+	fscb = kmalloc(sizeof(*fscb), GFP_KERNEL);
+	if (unlikely(!fscb))
+		return -ENOMEM;
+
 	sbi = sb->s_fs_info;
-	fscb = &sbi->s_fscb;
 
+	/* NOTE: We no longer dirty the super_block anywhere in exofs. The
+	 * reason we write the fscb here on unmount is so we can stay backwards
+	 * compatible with fscb->s_version == 1. (What we are not compatible
+	 * with is if a new version FS crashed and then we try to mount an old
+	 * version). Otherwise the exofs_fscb is read-only from mkfs time. All
+	 * the writeable info is set in exofs_sbi_write_stats() above.
+	 */
 	ret = exofs_get_io_state(&sbi->layout, &ios);
-	if (ret)
+	if (unlikely(ret))
 		goto out;
 
-	/* Note: We only write the changing part of the fscb. .i.e upto the
-	 *       the fscb->s_dev_table_oid member. There is no read-modify-write
-	 *       here.
-	 */
+	lock_super(sb);
+
 	ios->length = offsetof(struct exofs_fscb, s_dev_table_oid);
 	memset(fscb, 0, ios->length);
 	fscb->s_nextid = cpu_to_le64(sbi->s_nextid);
@@ -249,16 +351,17 @@ int exofs_sync_fs(struct super_block *sb, int wait)
 	ios->cred = sbi->s_cred;
 
 	ret = exofs_sbi_write(ios);
-	if (unlikely(ret)) {
+	if (unlikely(ret))
 		EXOFS_ERR("%s: exofs_sbi_write failed.\n", __func__);
-		goto out;
-	}
-	sb->s_dirt = 0;
+	else
+		sb->s_dirt = 0;
 
+
+	unlock_super(sb);
 out:
 	EXOFS_DBGMSG("s_nextid=0x%llx ret=%d\n", _LLU(sbi->s_nextid), ret);
 	exofs_put_io_state(ios);
-	unlock_super(sb);
+	kfree(fscb);
 	return ret;
 }
 
@@ -302,9 +405,6 @@ static void exofs_put_super(struct super_block *sb)
 	int num_pend;
 	struct exofs_sb_info *sbi = sb->s_fs_info;
 
-	if (sb->s_dirt)
-		exofs_write_super(sb);
-
 	/* make sure there are no pending commands */
 	for (num_pend = atomic_read(&sbi->s_curr_pending); num_pend > 0;
 	     num_pend = atomic_read(&sbi->s_curr_pending)) {
@@ -629,6 +729,7 @@ static int exofs_fill_super(struct super_block *sb, void *data, int silent)
 		goto free_sbi;
 
 	sb->s_magic = le16_to_cpu(fscb.s_magic);
+	/* NOTE: we read below to be backward compatible with old versions */
 	sbi->s_nextid = le64_to_cpu(fscb.s_nextid);
 	sbi->s_numfiles = le32_to_cpu(fscb.s_numfiles);
 
@@ -639,7 +740,7 @@ static int exofs_fill_super(struct super_block *sb, void *data, int silent)
 		ret = -EINVAL;
 		goto free_sbi;
 	}
-	if (le32_to_cpu(fscb.s_version) != EXOFS_FSCB_VER) {
+	if (le32_to_cpu(fscb.s_version) > EXOFS_FSCB_VER) {
 		EXOFS_ERR("ERROR: Bad FSCB version expected-%d got-%d\n",
 			  EXOFS_FSCB_VER, le32_to_cpu(fscb.s_version));
 		ret = -EINVAL;
@@ -657,6 +758,8 @@ static int exofs_fill_super(struct super_block *sb, void *data, int silent)
 			goto free_sbi;
 	}
 
+	__sbi_read_stats(sbi);
+
 	/* set up operation vectors */
 	sbi->bdi.ra_pages = __ra_pages(&sbi->layout);
 	sb->s_bdi = &sbi->bdi;
-- 
1.7.2.3

[PATCH 7/7] exofs: deprecate the commands pending counter

[Boaz Harrosh]

One leftover from the days of IBM's original code, is an SB counter
that counts in-flight asynchronous commands. And a piece of code that
waits for the counter to reach zero at unmount. I guess it might have
been needed then, cause of some reference missing or something.

I'm not removing it yet but am putting a warning message if ever this
counter triggers at unmount. If I'll never see it triggers or reported
I'll remove the counter for good.
(I had this print as a debug output for a long time and never had it
 trigger)

Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
---
 fs/exofs/super.c |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)

diff --git a/fs/exofs/super.c b/fs/exofs/super.c
index 2fa6df9..c4657db 100644
--- a/fs/exofs/super.c
+++ b/fs/exofs/super.c
@@ -409,6 +409,10 @@ static void exofs_put_super(struct super_block *sb)
 	for (num_pend = atomic_read(&sbi->s_curr_pending); num_pend > 0;
 	     num_pend = atomic_read(&sbi->s_curr_pending)) {
 		wait_queue_head_t wq;
+
+		printk(KERN_NOTICE "%s: !!Pending operations in flight. "
+		       "This is a BUG. please report to osd-dev@open-osd.org\n",
+		       __func__);
 		init_waitqueue_head(&wq);
 		wait_event_timeout(wq,
 				  (atomic_read(&sbi->s_curr_pending) == 0),
-- 
1.7.2.3