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-   -   GFS2: Extend the life of the reservations structure (http://www.linux-archive.org/cluster-development/655338-gfs2-extend-life-reservations-structure.html)

Bob Peterson 04-12-2012 03:43 PM

GFS2: Extend the life of the reservations structure
 
Hi,

This patch lengthens the life of the reservations structure.
See notes below.

Regards,

Bob Peterson
Red Hat GFS

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
--
Author: Bob Peterson <rpeterso@redhat.com>
Date: Thu Apr 12 11:37:24 2012 -0500

GFS2: Extend the life of the reservations structure

This patch lengthens the lifespan of the reservations structure for
inodes. Before, they were allocated and deallocated for every write
operation. With this patch, they are allocated when the first write
occurs, and deallocated when the last process closes the file.
It's more efficient to do it this way because it saves GFS2 a lot of
unnecessary allocates and frees. It also gives us more flexibility
for the future: (1) we can now fold the qadata structure back into
the structure and save those alloc/frees, (2) we can use this for
multi-block reservations.

diff --git a/fs/gfs2/aops.c b/fs/gfs2/aops.c
index 56dc1f0..a793957 100644
--- a/fs/gfs2/aops.c
+++ b/fs/gfs2/aops.c
@@ -879,7 +879,7 @@ static int gfs2_write_end(struct file *file, struct address_space *mapping,
brelse(dibh);
failed:
gfs2_trans_end(sdp);
- if (ip->i_res)
+ if (gfs2_mb_reserved(ip))
gfs2_inplace_release(ip);
if (qa) {
gfs2_quota_unlock(ip);
diff --git a/fs/gfs2/file.c b/fs/gfs2/file.c
index 31b199f..3a1a60a 100644
--- a/fs/gfs2/file.c
+++ b/fs/gfs2/file.c
@@ -384,6 +384,10 @@ static int gfs2_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
set_bit(GLF_DIRTY, &ip->i_gl->gl_flags);
set_bit(GIF_SW_PAGED, &ip->i_flags);

+ ret = gfs2_rs_alloc(ip);
+ if (ret)
+ goto out_unlock;
+
if (!gfs2_write_alloc_required(ip, pos, PAGE_CACHE_SIZE)) {
lock_page(page);
if (!PageUptodate(page) || page->mapping != inode->i_mapping) {
@@ -569,10 +573,17 @@ static int gfs2_release(struct inode *inode, struct file *file)
{
struct gfs2_sbd *sdp = inode->i_sb->s_fs_info;
struct gfs2_file *fp;
+ struct gfs2_inode *ip = GFS2_I(inode);

fp = file->private_data;
file->private_data = NULL;

+ if (file->f_mode & FMODE_WRITE) {
+ mutex_lock(&inode->i_mutex);
+ if (ip->i_res && (atomic_read(&inode->i_writecount) == 1))
+ gfs2_rs_delete(ip);
+ mutex_unlock(&inode->i_mutex);
+ }
if (gfs2_assert_warn(sdp, fp))
return -EIO;

@@ -653,12 +664,16 @@ static ssize_t gfs2_file_aio_write(struct kiocb *iocb, const struct iovec *iov,
unsigned long nr_segs, loff_t pos)
{
struct file *file = iocb->ki_filp;
+ struct dentry *dentry = file->f_dentry;
+ struct gfs2_inode *ip = GFS2_I(dentry->d_inode);
+ int ret;
+
+ ret = gfs2_rs_alloc(ip);
+ if (ret)
+ return ret;

if (file->f_flags & O_APPEND) {
- struct dentry *dentry = file->f_dentry;
- struct gfs2_inode *ip = GFS2_I(dentry->d_inode);
struct gfs2_holder gh;
- int ret;

ret = gfs2_glock_nq_init(ip->i_gl, LM_ST_SHARED, 0, &gh);
if (ret)
diff --git a/fs/gfs2/inode.c b/fs/gfs2/inode.c
index a9ba244..127b1a4 100644
--- a/fs/gfs2/inode.c
+++ b/fs/gfs2/inode.c
@@ -681,6 +681,10 @@ static int gfs2_create_inode(struct inode *dir, struct dentry *dentry,
if (error)
goto fail_gunlock;

+ error = gfs2_rs_alloc(dip);
+ if (error)
+ goto fail_gunlock;
+
error = alloc_dinode(dip, &inum.no_addr, &generation);
if (error)
goto fail_gunlock;
@@ -704,6 +708,11 @@ static int gfs2_create_inode(struct inode *dir, struct dentry *dentry,
if (error)
goto fail_gunlock2;

+ /* the new inode needs a reservation so it can allocate xattrs. */
+ error = gfs2_rs_alloc(GFS2_I(inode));
+ if (error)
+ goto fail_gunlock2;
+
error = gfs2_acl_create(dip, inode);
if (error)
goto fail_gunlock2;
@@ -722,7 +731,7 @@ static int gfs2_create_inode(struct inode *dir, struct dentry *dentry,
gfs2_trans_end(sdp);
/* Check if we reserved space in the rgrp. Function link_dinode may
not, depending on whether alloc is required. */
- if (dip->i_res)
+ if (gfs2_mb_reserved(dip))
gfs2_inplace_release(dip);
gfs2_quota_unlock(dip);
gfs2_qadata_put(dip);
@@ -734,6 +743,7 @@ static int gfs2_create_inode(struct inode *dir, struct dentry *dentry,
fail_gunlock2:
gfs2_glock_dq_uninit(ghs + 1);
fail_gunlock:
+ gfs2_rs_delete(dip);
gfs2_glock_dq_uninit(ghs);
if (inode && !IS_ERR(inode)) {
set_bit(GIF_ALLOC_FAILED, &GFS2_I(inode)->i_flags);
diff --git a/fs/gfs2/rgrp.c b/fs/gfs2/rgrp.c
index 146c3d2..af590de 100644
--- a/fs/gfs2/rgrp.c
+++ b/fs/gfs2/rgrp.c
@@ -418,6 +418,34 @@ void gfs2_free_clones(struct gfs2_rgrpd *rgd)
}
}

+/**
+ * gfs2_rs_alloc - make sure we have a reservation assigned to the inode
+ * @ip: the inode for this reservation
+ */
+int gfs2_rs_alloc(struct gfs2_inode *ip)
+{
+ if (ip->i_res)
+ return 0;
+ ip->i_res = kmem_cache_zalloc(gfs2_rsrv_cachep, GFP_NOFS);
+ if (!ip->i_res)
+ return -ENOMEM;
+ return 0;
+}
+
+/**
+ * gfs2_rs_delete - delete a reservation
+ * @ip: The inode for this reservation
+ *
+ */
+void gfs2_rs_delete(struct gfs2_inode *ip)
+{
+ if (ip->i_res == NULL)
+ return;
+
+ kmem_cache_free(gfs2_rsrv_cachep, ip->i_res);
+ ip->i_res = NULL;
+}
+
void gfs2_clear_rgrpd(struct gfs2_sbd *sdp)
{
struct rb_node *n;
@@ -1001,22 +1029,6 @@ struct gfs2_qadata *gfs2_qadata_get(struct gfs2_inode *ip)
}

/**
- * gfs2_blkrsv_get - get the struct gfs2_blkreserv structure for an inode
- * @ip: the incore GFS2 inode structure
- *
- * Returns: the struct gfs2_qadata
- */
-
-static int gfs2_blkrsv_get(struct gfs2_inode *ip)
-{
- BUG_ON(ip->i_res != NULL);
- ip->i_res = kmem_cache_zalloc(gfs2_rsrv_cachep, GFP_NOFS);
- if (!ip->i_res)
- return -ENOMEM;
- return 0;
-}
-
-/**
* try_rgrp_fit - See if a given reservation will fit in a given RG
* @rgd: the RG data
* @ip: the inode
@@ -1170,13 +1182,6 @@ static int get_local_rgrp(struct gfs2_inode *ip, u64 *last_unlinked)
return -ENOSPC;
}

-static void gfs2_blkrsv_put(struct gfs2_inode *ip)
-{
- BUG_ON(ip->i_res == NULL);
- kmem_cache_free(gfs2_rsrv_cachep, ip->i_res);
- ip->i_res = NULL;
-}
-
/**
* gfs2_inplace_reserve - Reserve space in the filesystem
* @ip: the inode to reserve space for
@@ -1189,14 +1194,10 @@ int gfs2_inplace_reserve(struct gfs2_inode *ip, u32 requested)
{
struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
struct gfs2_blkreserv *rs;
- int error;
+ int error = 0;
u64 last_unlinked = NO_BLOCK;
int tries = 0;

- error = gfs2_blkrsv_get(ip);
- if (error)
- return error;
-
rs = ip->i_res;
rs->rs_requested = requested;
if (gfs2_assert_warn(sdp, requested)) {
@@ -1221,7 +1222,7 @@ int gfs2_inplace_reserve(struct gfs2_inode *ip, u32 requested)

out:
if (error)
- gfs2_blkrsv_put(ip);
+ rs->rs_requested = 0;
return error;
}

@@ -1238,7 +1239,7 @@ void gfs2_inplace_release(struct gfs2_inode *ip)

if (rs->rs_rgd_gh.gh_gl)
gfs2_glock_dq_uninit(&rs->rs_rgd_gh);
- gfs2_blkrsv_put(ip);
+ rs->rs_requested = 0;
}

/**
@@ -1506,7 +1507,7 @@ int gfs2_alloc_blocks(struct gfs2_inode *ip, u64 *bn, unsigned int *nblocks,
/* Only happens if there is a bug in gfs2, return something distinctive
* to ensure that it is noticed.
*/
- if (ip->i_res == NULL)
+ if (ip->i_res->rs_requested == 0)
return -ECANCELED;

rgd = ip->i_rgd;
diff --git a/fs/gfs2/rgrp.h b/fs/gfs2/rgrp.h
index b4b10f4..d9eda5f 100644
--- a/fs/gfs2/rgrp.h
+++ b/fs/gfs2/rgrp.h
@@ -43,6 +43,8 @@ extern void gfs2_inplace_release(struct gfs2_inode *ip);
extern int gfs2_alloc_blocks(struct gfs2_inode *ip, u64 *bn, unsigned int *n,
bool dinode, u64 *generation);

+extern int gfs2_rs_alloc(struct gfs2_inode *ip);
+extern void gfs2_rs_delete(struct gfs2_inode *ip);
extern void __gfs2_free_blocks(struct gfs2_inode *ip, u64 bstart, u32 blen, int meta);
extern void gfs2_free_meta(struct gfs2_inode *ip, u64 bstart, u32 blen);
extern void gfs2_free_di(struct gfs2_rgrpd *rgd, struct gfs2_inode *ip);
@@ -68,4 +70,12 @@ extern int gfs2_rgrp_send_discards(struct gfs2_sbd *sdp, u64 offset,
const struct gfs2_bitmap *bi, unsigned minlen, u64 *ptrimmed);
extern int gfs2_fitrim(struct file *filp, void __user *argp);

+/* This is how to tell if a reservation is "inplace" reserved: */
+static inline int gfs2_mb_reserved(struct gfs2_inode *ip)
+{
+ if (ip->i_res && ip->i_res->rs_requested)
+ return 1;
+ return 0;
+}
+
#endif /* __RGRP_DOT_H__ */
diff --git a/fs/gfs2/super.c b/fs/gfs2/super.c
index 6172fa7..a42df66 100644
--- a/fs/gfs2/super.c
+++ b/fs/gfs2/super.c
@@ -1554,6 +1554,7 @@ out_unlock:
out:
/* Case 3 starts here */
truncate_inode_pages(&inode->i_data, 0);
+ gfs2_rs_delete(ip);
end_writeback(inode);
gfs2_dir_hash_inval(ip);
ip->i_gl->gl_object = NULL;
@@ -1576,6 +1577,7 @@ static struct inode *gfs2_alloc_inode(struct super_block *sb)
ip->i_flags = 0;
ip->i_gl = NULL;
ip->i_rgd = NULL;
+ ip->i_res = NULL;
}
return &ip->i_inode;
}
diff --git a/fs/gfs2/trans.h b/fs/gfs2/trans.h
index 125d457..41f42cd 100644
--- a/fs/gfs2/trans.h
+++ b/fs/gfs2/trans.h
@@ -31,7 +31,7 @@ struct gfs2_glock;
static inline unsigned int gfs2_rg_blocks(const struct gfs2_inode *ip)
{
const struct gfs2_blkreserv *rs = ip->i_res;
- if (rs->rs_requested < ip->i_rgd->rd_length)
+ if (rs && rs->rs_requested < ip->i_rgd->rd_length)
return rs->rs_requested + 1;
return ip->i_rgd->rd_length;
}

Bob Peterson 05-09-2012 04:22 PM

GFS2: Extend the life of the reservations structure
 
Hi,

This is a second attempt at this patch. Explanation is below.

The idea here is to extend the lifespan of the block reservations
structure. This has three benefits: First, for performance, GFS2
spends less time allocating and freeing memory for this purpose
and can re-use the structure already attached to the inode.
Second, it allows us to re-combine the quota structure in a
to save the time we spend allocating and freeing that, in a future
patch. Third, it sets us up for the forthcoming multi-block
reservations patch.

There was an issue with the predecessor patch not doing any locking
during the allocating and freeing of the reservations for an inode.
This patch re-purposes the gfs2 i_rw_mutex (to save memory) to
protect the allocations and deletes. I couldn't see any places where
this could conflict or deadlock with existing uses of the mutex.

Regards,

Bob Peterson
Red Hat File Systems

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
---
Author: Bob Peterson <rpeterso@redhat.com>
Date: Thu Apr 12 11:37:24 2012 -0500

GFS2: Extend the life of the reservations structure

This patch lengthens the lifespan of the reservations structure for
inodes. Before, they were allocated and deallocated for every write
operation. With this patch, they are allocated when the first write
occurs, and deallocated when the last process closes the file.
It's more efficient to do it this way because it saves GFS2 a lot of
unnecessary allocates and frees. It also gives us more flexibility
for the future: (1) we can now fold the qadata structure back into
the structure and save those alloc/frees, (2) we can use this for
multi-block reservations.

diff --git a/fs/gfs2/aops.c b/fs/gfs2/aops.c
index e80a464..aba77b5 100644
--- a/fs/gfs2/aops.c
+++ b/fs/gfs2/aops.c
@@ -878,7 +878,7 @@ static int gfs2_write_end(struct file *file, struct address_space *mapping,
brelse(dibh);
failed:
gfs2_trans_end(sdp);
- if (ip->i_res)
+ if (gfs2_mb_reserved(ip))
gfs2_inplace_release(ip);
if (qa) {
gfs2_quota_unlock(ip);
diff --git a/fs/gfs2/file.c b/fs/gfs2/file.c
index 31b199f..3790617 100644
--- a/fs/gfs2/file.c
+++ b/fs/gfs2/file.c
@@ -376,6 +376,10 @@ static int gfs2_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
*/
vfs_check_frozen(inode->i_sb, SB_FREEZE_WRITE);

+ ret = gfs2_rs_alloc(ip);
+ if (ret)
+ return ret;
+
gfs2_holder_init(ip->i_gl, LM_ST_EXCLUSIVE, 0, &gh);
ret = gfs2_glock_nq(&gh);
if (ret)
@@ -569,10 +573,15 @@ static int gfs2_release(struct inode *inode, struct file *file)
{
struct gfs2_sbd *sdp = inode->i_sb->s_fs_info;
struct gfs2_file *fp;
+ struct gfs2_inode *ip = GFS2_I(inode);

fp = file->private_data;
file->private_data = NULL;

+ if ((file->f_mode & FMODE_WRITE) && ip->i_res &&
+ (atomic_read(&inode->i_writecount) == 1))
+ gfs2_rs_delete(ip);
+
if (gfs2_assert_warn(sdp, fp))
return -EIO;

@@ -653,12 +662,16 @@ static ssize_t gfs2_file_aio_write(struct kiocb *iocb, const struct iovec *iov,
unsigned long nr_segs, loff_t pos)
{
struct file *file = iocb->ki_filp;
+ struct dentry *dentry = file->f_dentry;
+ struct gfs2_inode *ip = GFS2_I(dentry->d_inode);
+ int ret;
+
+ ret = gfs2_rs_alloc(ip);
+ if (ret)
+ return ret;

if (file->f_flags & O_APPEND) {
- struct dentry *dentry = file->f_dentry;
- struct gfs2_inode *ip = GFS2_I(dentry->d_inode);
struct gfs2_holder gh;
- int ret;

ret = gfs2_glock_nq_init(ip->i_gl, LM_ST_SHARED, 0, &gh);
if (ret)
@@ -774,6 +787,10 @@ static long gfs2_fallocate(struct file *file, int mode, loff_t offset,
if (bytes == 0)
bytes = sdp->sd_sb.sb_bsize;

+ error = gfs2_rs_alloc(ip);
+ if (error)
+ return error;
+
gfs2_holder_init(ip->i_gl, LM_ST_EXCLUSIVE, 0, &ip->i_gh);
error = gfs2_glock_nq(&ip->i_gh);
if (unlikely(error))
diff --git a/fs/gfs2/inode.c b/fs/gfs2/inode.c
index a9ba244..6a46417 100644
--- a/fs/gfs2/inode.c
+++ b/fs/gfs2/inode.c
@@ -667,6 +667,10 @@ static int gfs2_create_inode(struct inode *dir, struct dentry *dentry,
if (!name->len || name->len > GFS2_FNAMESIZE)
return -ENAMETOOLONG;

+ error = gfs2_rs_alloc(dip);
+ if (error)
+ return error;
+
error = gfs2_glock_nq_init(dip->i_gl, LM_ST_EXCLUSIVE, 0, ghs);
if (error)
goto fail;
@@ -704,6 +708,11 @@ static int gfs2_create_inode(struct inode *dir, struct dentry *dentry,
if (error)
goto fail_gunlock2;

+ /* the new inode needs a reservation so it can allocate xattrs. */
+ error = gfs2_rs_alloc(GFS2_I(inode));
+ if (error)
+ goto fail_gunlock2;
+
error = gfs2_acl_create(dip, inode);
if (error)
goto fail_gunlock2;
@@ -722,7 +731,7 @@ static int gfs2_create_inode(struct inode *dir, struct dentry *dentry,
gfs2_trans_end(sdp);
/* Check if we reserved space in the rgrp. Function link_dinode may
not, depending on whether alloc is required. */
- if (dip->i_res)
+ if (gfs2_mb_reserved(dip))
gfs2_inplace_release(dip);
gfs2_quota_unlock(dip);
gfs2_qadata_put(dip);
@@ -740,6 +749,7 @@ fail_gunlock:
iput(inode);
}
fail:
+ gfs2_rs_delete(dip);
if (bh)
brelse(bh);
return error;
diff --git a/fs/gfs2/rgrp.c b/fs/gfs2/rgrp.c
index f74fb9b..e944fef 100644
--- a/fs/gfs2/rgrp.c
+++ b/fs/gfs2/rgrp.c
@@ -417,6 +417,39 @@ void gfs2_free_clones(struct gfs2_rgrpd *rgd)
}
}

+/**
+ * gfs2_rs_alloc - make sure we have a reservation assigned to the inode
+ * @ip: the inode for this reservation
+ */
+int gfs2_rs_alloc(struct gfs2_inode *ip)
+{
+ int error = 0;
+
+ down_write(&ip->i_rw_mutex);
+ if (!ip->i_res) {
+ ip->i_res = kmem_cache_zalloc(gfs2_rsrv_cachep, GFP_NOFS);
+ if (!ip->i_res)
+ error = -ENOMEM;
+ }
+ up_write(&ip->i_rw_mutex);
+ return error;
+}
+
+/**
+ * gfs2_rs_delete - delete a reservation
+ * @ip: The inode for this reservation
+ *
+ */
+void gfs2_rs_delete(struct gfs2_inode *ip)
+{
+ down_write(&ip->i_rw_mutex);
+ if (ip->i_res) {
+ kmem_cache_free(gfs2_rsrv_cachep, ip->i_res);
+ ip->i_res = NULL;
+ }
+ up_write(&ip->i_rw_mutex);
+}
+
void gfs2_clear_rgrpd(struct gfs2_sbd *sdp)
{
struct rb_node *n;
@@ -993,22 +1026,6 @@ struct gfs2_qadata *gfs2_qadata_get(struct gfs2_inode *ip)
}

/**
- * gfs2_blkrsv_get - get the struct gfs2_blkreserv structure for an inode
- * @ip: the incore GFS2 inode structure
- *
- * Returns: the struct gfs2_qadata
- */
-
-static int gfs2_blkrsv_get(struct gfs2_inode *ip)
-{
- BUG_ON(ip->i_res != NULL);
- ip->i_res = kmem_cache_zalloc(gfs2_rsrv_cachep, GFP_NOFS);
- if (!ip->i_res)
- return -ENOMEM;
- return 0;
-}
-
-/**
* try_rgrp_fit - See if a given reservation will fit in a given RG
* @rgd: the RG data
* @ip: the inode
@@ -1162,13 +1179,6 @@ static int get_local_rgrp(struct gfs2_inode *ip, u64 *last_unlinked)
return -ENOSPC;
}

-static void gfs2_blkrsv_put(struct gfs2_inode *ip)
-{
- BUG_ON(ip->i_res == NULL);
- kmem_cache_free(gfs2_rsrv_cachep, ip->i_res);
- ip->i_res = NULL;
-}
-
/**
* gfs2_inplace_reserve - Reserve space in the filesystem
* @ip: the inode to reserve space for
@@ -1181,14 +1191,10 @@ int gfs2_inplace_reserve(struct gfs2_inode *ip, u32 requested)
{
struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
struct gfs2_blkreserv *rs;
- int error;
+ int error = 0;
u64 last_unlinked = NO_BLOCK;
int tries = 0;

- error = gfs2_blkrsv_get(ip);
- if (error)
- return error;
-
rs = ip->i_res;
rs->rs_requested = requested;
if (gfs2_assert_warn(sdp, requested)) {
@@ -1213,7 +1219,7 @@ int gfs2_inplace_reserve(struct gfs2_inode *ip, u32 requested)

out:
if (error)
- gfs2_blkrsv_put(ip);
+ rs->rs_requested = 0;
return error;
}

@@ -1230,7 +1236,7 @@ void gfs2_inplace_release(struct gfs2_inode *ip)

if (rs->rs_rgd_gh.gh_gl)
gfs2_glock_dq_uninit(&rs->rs_rgd_gh);
- gfs2_blkrsv_put(ip);
+ rs->rs_requested = 0;
}

/**
@@ -1496,7 +1502,7 @@ int gfs2_alloc_blocks(struct gfs2_inode *ip, u64 *bn, unsigned int *nblocks,
/* Only happens if there is a bug in gfs2, return something distinctive
* to ensure that it is noticed.
*/
- if (ip->i_res == NULL)
+ if (ip->i_res->rs_requested == 0)
return -ECANCELED;

rgd = ip->i_rgd;
diff --git a/fs/gfs2/rgrp.h b/fs/gfs2/rgrp.h
index b4b10f4..d9eda5f 100644
--- a/fs/gfs2/rgrp.h
+++ b/fs/gfs2/rgrp.h
@@ -43,6 +43,8 @@ extern void gfs2_inplace_release(struct gfs2_inode *ip);
extern int gfs2_alloc_blocks(struct gfs2_inode *ip, u64 *bn, unsigned int *n,
bool dinode, u64 *generation);

+extern int gfs2_rs_alloc(struct gfs2_inode *ip);
+extern void gfs2_rs_delete(struct gfs2_inode *ip);
extern void __gfs2_free_blocks(struct gfs2_inode *ip, u64 bstart, u32 blen, int meta);
extern void gfs2_free_meta(struct gfs2_inode *ip, u64 bstart, u32 blen);
extern void gfs2_free_di(struct gfs2_rgrpd *rgd, struct gfs2_inode *ip);
@@ -68,4 +70,12 @@ extern int gfs2_rgrp_send_discards(struct gfs2_sbd *sdp, u64 offset,
const struct gfs2_bitmap *bi, unsigned minlen, u64 *ptrimmed);
extern int gfs2_fitrim(struct file *filp, void __user *argp);

+/* This is how to tell if a reservation is "inplace" reserved: */
+static inline int gfs2_mb_reserved(struct gfs2_inode *ip)
+{
+ if (ip->i_res && ip->i_res->rs_requested)
+ return 1;
+ return 0;
+}
+
#endif /* __RGRP_DOT_H__ */
diff --git a/fs/gfs2/super.c b/fs/gfs2/super.c
index 6172fa7..a42df66 100644
--- a/fs/gfs2/super.c
+++ b/fs/gfs2/super.c
@@ -1554,6 +1554,7 @@ out_unlock:
out:
/* Case 3 starts here */
truncate_inode_pages(&inode->i_data, 0);
+ gfs2_rs_delete(ip);
end_writeback(inode);
gfs2_dir_hash_inval(ip);
ip->i_gl->gl_object = NULL;
@@ -1576,6 +1577,7 @@ static struct inode *gfs2_alloc_inode(struct super_block *sb)
ip->i_flags = 0;
ip->i_gl = NULL;
ip->i_rgd = NULL;
+ ip->i_res = NULL;
}
return &ip->i_inode;
}
diff --git a/fs/gfs2/trans.h b/fs/gfs2/trans.h
index 125d457..41f42cd 100644
--- a/fs/gfs2/trans.h
+++ b/fs/gfs2/trans.h
@@ -31,7 +31,7 @@ struct gfs2_glock;
static inline unsigned int gfs2_rg_blocks(const struct gfs2_inode *ip)
{
const struct gfs2_blkreserv *rs = ip->i_res;
- if (rs->rs_requested < ip->i_rgd->rd_length)
+ if (rs && rs->rs_requested < ip->i_rgd->rd_length)
return rs->rs_requested + 1;
return ip->i_rgd->rd_length;
}

Bob Peterson 05-18-2012 11:00 AM

GFS2: Extend the life of the reservations structure
 
Hi,

Sorry for the problems encountered on try #3 of this patch.
For Try #4, I've systematically gone through all the places where
a reservation is necessary, and made sure one was created.
I've also tested it with quotas enabled against postmark, fs_mark,
and iozone.

This patch lengthens the lifespan of the reservations structure for
inodes. Before, they were allocated and deallocated for every write
operation. With this patch, they are allocated when the first write
occurs, and deallocated when the last process closes the file.
It's more efficient to do it this way because it saves GFS2 a lot of
unnecessary allocates and frees. It also gives us more flexibility
for the future: (1) we can now fold the qadata structure back into
the structure and save those alloc/frees, (2) we can use this for
multi-block reservations.

Regards,

Bob Peterson
Red Hat File Systems

Signed-off-by: Bob Peterson <rpeterso@redhat.com>
---
diff --git a/fs/gfs2/aops.c b/fs/gfs2/aops.c
index e80a464..aba77b5 100644
--- a/fs/gfs2/aops.c
+++ b/fs/gfs2/aops.c
@@ -878,7 +878,7 @@ static int gfs2_write_end(struct file *file, struct address_space *mapping,
brelse(dibh);
failed:
gfs2_trans_end(sdp);
- if (ip->i_res)
+ if (gfs2_mb_reserved(ip))
gfs2_inplace_release(ip);
if (qa) {
gfs2_quota_unlock(ip);
diff --git a/fs/gfs2/file.c b/fs/gfs2/file.c
index 31b199f..3790617 100644
--- a/fs/gfs2/file.c
+++ b/fs/gfs2/file.c
@@ -376,6 +376,10 @@ static int gfs2_page_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf)
*/
vfs_check_frozen(inode->i_sb, SB_FREEZE_WRITE);

+ ret = gfs2_rs_alloc(ip);
+ if (ret)
+ return ret;
+
gfs2_holder_init(ip->i_gl, LM_ST_EXCLUSIVE, 0, &gh);
ret = gfs2_glock_nq(&gh);
if (ret)
@@ -569,10 +573,15 @@ static int gfs2_release(struct inode *inode, struct file *file)
{
struct gfs2_sbd *sdp = inode->i_sb->s_fs_info;
struct gfs2_file *fp;
+ struct gfs2_inode *ip = GFS2_I(inode);

fp = file->private_data;
file->private_data = NULL;

+ if ((file->f_mode & FMODE_WRITE) && ip->i_res &&
+ (atomic_read(&inode->i_writecount) == 1))
+ gfs2_rs_delete(ip);
+
if (gfs2_assert_warn(sdp, fp))
return -EIO;

@@ -653,12 +662,16 @@ static ssize_t gfs2_file_aio_write(struct kiocb *iocb, const struct iovec *iov,
unsigned long nr_segs, loff_t pos)
{
struct file *file = iocb->ki_filp;
+ struct dentry *dentry = file->f_dentry;
+ struct gfs2_inode *ip = GFS2_I(dentry->d_inode);
+ int ret;
+
+ ret = gfs2_rs_alloc(ip);
+ if (ret)
+ return ret;

if (file->f_flags & O_APPEND) {
- struct dentry *dentry = file->f_dentry;
- struct gfs2_inode *ip = GFS2_I(dentry->d_inode);
struct gfs2_holder gh;
- int ret;

ret = gfs2_glock_nq_init(ip->i_gl, LM_ST_SHARED, 0, &gh);
if (ret)
@@ -774,6 +787,10 @@ static long gfs2_fallocate(struct file *file, int mode, loff_t offset,
if (bytes == 0)
bytes = sdp->sd_sb.sb_bsize;

+ error = gfs2_rs_alloc(ip);
+ if (error)
+ return error;
+
gfs2_holder_init(ip->i_gl, LM_ST_EXCLUSIVE, 0, &ip->i_gh);
error = gfs2_glock_nq(&ip->i_gh);
if (unlikely(error))
diff --git a/fs/gfs2/inode.c b/fs/gfs2/inode.c
index a9ba244..2a1b4b5 100644
--- a/fs/gfs2/inode.c
+++ b/fs/gfs2/inode.c
@@ -667,6 +667,10 @@ static int gfs2_create_inode(struct inode *dir, struct dentry *dentry,
if (!name->len || name->len > GFS2_FNAMESIZE)
return -ENAMETOOLONG;

+ error = gfs2_rs_alloc(dip);
+ if (error)
+ return error;
+
error = gfs2_glock_nq_init(dip->i_gl, LM_ST_EXCLUSIVE, 0, ghs);
if (error)
goto fail;
@@ -704,6 +708,11 @@ static int gfs2_create_inode(struct inode *dir, struct dentry *dentry,
if (error)
goto fail_gunlock2;

+ /* the new inode needs a reservation so it can allocate xattrs. */
+ error = gfs2_rs_alloc(GFS2_I(inode));
+ if (error)
+ goto fail_gunlock2;
+
error = gfs2_acl_create(dip, inode);
if (error)
goto fail_gunlock2;
@@ -722,7 +731,7 @@ static int gfs2_create_inode(struct inode *dir, struct dentry *dentry,
gfs2_trans_end(sdp);
/* Check if we reserved space in the rgrp. Function link_dinode may
not, depending on whether alloc is required. */
- if (dip->i_res)
+ if (gfs2_mb_reserved(dip))
gfs2_inplace_release(dip);
gfs2_quota_unlock(dip);
gfs2_qadata_put(dip);
@@ -819,6 +828,10 @@ static int gfs2_link(struct dentry *old_dentry, struct inode *dir,
if (S_ISDIR(inode->i_mode))
return -EPERM;

+ error = gfs2_rs_alloc(dip);
+ if (error)
+ return error;
+
gfs2_holder_init(dip->i_gl, LM_ST_EXCLUSIVE, 0, ghs);
gfs2_holder_init(ip->i_gl, LM_ST_EXCLUSIVE, 0, ghs + 1);

@@ -1234,6 +1247,10 @@ static int gfs2_rename(struct inode *odir, struct dentry *odentry,
if (error)
return error;

+ error = gfs2_rs_alloc(ndip);
+ if (error)
+ return error;
+
if (odip != ndip) {
error = gfs2_glock_nq_init(sdp->sd_rename_gl, LM_ST_EXCLUSIVE,
0, &r_gh);
@@ -1644,6 +1661,10 @@ static int gfs2_setattr(struct dentry *dentry, struct iattr *attr)
struct gfs2_holder i_gh;
int error;

+ error = gfs2_rs_alloc(ip);
+ if (error)
+ return error;
+
error = gfs2_glock_nq_init(ip->i_gl, LM_ST_EXCLUSIVE, 0, &i_gh);
if (error)
return error;
diff --git a/fs/gfs2/quota.c b/fs/gfs2/quota.c
index b97178e..197cc2d 100644
--- a/fs/gfs2/quota.c
+++ b/fs/gfs2/quota.c
@@ -764,6 +764,10 @@ static int do_sync(unsigned int num_qd, struct gfs2_quota_data **qda)
unsigned int nalloc = 0, blocks;
int error;

+ error = gfs2_rs_alloc(ip);
+ if (error)
+ return error;
+
gfs2_write_calc_reserv(ip, sizeof(struct gfs2_quota),
&data_blocks, &ind_blocks);

@@ -1549,10 +1553,14 @@ static int gfs2_set_dqblk(struct super_block *sb, int type, qid_t id,
if (error)
return error;

+ error = gfs2_rs_alloc(ip);
+ if (error)
+ goto out_put;
+
mutex_lock(&ip->i_inode.i_mutex);
error = gfs2_glock_nq_init(qd->qd_gl, LM_ST_EXCLUSIVE, 0, &q_gh);
if (error)
- goto out_put;
+ goto out_unlockput;
error = gfs2_glock_nq_init(ip->i_gl, LM_ST_EXCLUSIVE, 0, &i_gh);
if (error)
goto out_q;
@@ -1609,8 +1617,9 @@ out_i:
gfs2_glock_dq_uninit(&i_gh);
out_q:
gfs2_glock_dq_uninit(&q_gh);
-out_put:
+out_unlockput:
mutex_unlock(&ip->i_inode.i_mutex);
+out_put:
qd_put(qd);
return error;
}
diff --git a/fs/gfs2/rgrp.c b/fs/gfs2/rgrp.c
index f74fb9b..e944fef 100644
--- a/fs/gfs2/rgrp.c
+++ b/fs/gfs2/rgrp.c
@@ -417,6 +417,39 @@ void gfs2_free_clones(struct gfs2_rgrpd *rgd)
}
}

+/**
+ * gfs2_rs_alloc - make sure we have a reservation assigned to the inode
+ * @ip: the inode for this reservation
+ */
+int gfs2_rs_alloc(struct gfs2_inode *ip)
+{
+ int error = 0;
+
+ down_write(&ip->i_rw_mutex);
+ if (!ip->i_res) {
+ ip->i_res = kmem_cache_zalloc(gfs2_rsrv_cachep, GFP_NOFS);
+ if (!ip->i_res)
+ error = -ENOMEM;
+ }
+ up_write(&ip->i_rw_mutex);
+ return error;
+}
+
+/**
+ * gfs2_rs_delete - delete a reservation
+ * @ip: The inode for this reservation
+ *
+ */
+void gfs2_rs_delete(struct gfs2_inode *ip)
+{
+ down_write(&ip->i_rw_mutex);
+ if (ip->i_res) {
+ kmem_cache_free(gfs2_rsrv_cachep, ip->i_res);
+ ip->i_res = NULL;
+ }
+ up_write(&ip->i_rw_mutex);
+}
+
void gfs2_clear_rgrpd(struct gfs2_sbd *sdp)
{
struct rb_node *n;
@@ -993,22 +1026,6 @@ struct gfs2_qadata *gfs2_qadata_get(struct gfs2_inode *ip)
}

/**
- * gfs2_blkrsv_get - get the struct gfs2_blkreserv structure for an inode
- * @ip: the incore GFS2 inode structure
- *
- * Returns: the struct gfs2_qadata
- */
-
-static int gfs2_blkrsv_get(struct gfs2_inode *ip)
-{
- BUG_ON(ip->i_res != NULL);
- ip->i_res = kmem_cache_zalloc(gfs2_rsrv_cachep, GFP_NOFS);
- if (!ip->i_res)
- return -ENOMEM;
- return 0;
-}
-
-/**
* try_rgrp_fit - See if a given reservation will fit in a given RG
* @rgd: the RG data
* @ip: the inode
@@ -1162,13 +1179,6 @@ static int get_local_rgrp(struct gfs2_inode *ip, u64 *last_unlinked)
return -ENOSPC;
}

-static void gfs2_blkrsv_put(struct gfs2_inode *ip)
-{
- BUG_ON(ip->i_res == NULL);
- kmem_cache_free(gfs2_rsrv_cachep, ip->i_res);
- ip->i_res = NULL;
-}
-
/**
* gfs2_inplace_reserve - Reserve space in the filesystem
* @ip: the inode to reserve space for
@@ -1181,14 +1191,10 @@ int gfs2_inplace_reserve(struct gfs2_inode *ip, u32 requested)
{
struct gfs2_sbd *sdp = GFS2_SB(&ip->i_inode);
struct gfs2_blkreserv *rs;
- int error;
+ int error = 0;
u64 last_unlinked = NO_BLOCK;
int tries = 0;

- error = gfs2_blkrsv_get(ip);
- if (error)
- return error;
-
rs = ip->i_res;
rs->rs_requested = requested;
if (gfs2_assert_warn(sdp, requested)) {
@@ -1213,7 +1219,7 @@ int gfs2_inplace_reserve(struct gfs2_inode *ip, u32 requested)

out:
if (error)
- gfs2_blkrsv_put(ip);
+ rs->rs_requested = 0;
return error;
}

@@ -1230,7 +1236,7 @@ void gfs2_inplace_release(struct gfs2_inode *ip)

if (rs->rs_rgd_gh.gh_gl)
gfs2_glock_dq_uninit(&rs->rs_rgd_gh);
- gfs2_blkrsv_put(ip);
+ rs->rs_requested = 0;
}

/**
@@ -1496,7 +1502,7 @@ int gfs2_alloc_blocks(struct gfs2_inode *ip, u64 *bn, unsigned int *nblocks,
/* Only happens if there is a bug in gfs2, return something distinctive
* to ensure that it is noticed.
*/
- if (ip->i_res == NULL)
+ if (ip->i_res->rs_requested == 0)
return -ECANCELED;

rgd = ip->i_rgd;
diff --git a/fs/gfs2/rgrp.h b/fs/gfs2/rgrp.h
index b4b10f4..d9eda5f 100644
--- a/fs/gfs2/rgrp.h
+++ b/fs/gfs2/rgrp.h
@@ -43,6 +43,8 @@ extern void gfs2_inplace_release(struct gfs2_inode *ip);
extern int gfs2_alloc_blocks(struct gfs2_inode *ip, u64 *bn, unsigned int *n,
bool dinode, u64 *generation);

+extern int gfs2_rs_alloc(struct gfs2_inode *ip);
+extern void gfs2_rs_delete(struct gfs2_inode *ip);
extern void __gfs2_free_blocks(struct gfs2_inode *ip, u64 bstart, u32 blen, int meta);
extern void gfs2_free_meta(struct gfs2_inode *ip, u64 bstart, u32 blen);
extern void gfs2_free_di(struct gfs2_rgrpd *rgd, struct gfs2_inode *ip);
@@ -68,4 +70,12 @@ extern int gfs2_rgrp_send_discards(struct gfs2_sbd *sdp, u64 offset,
const struct gfs2_bitmap *bi, unsigned minlen, u64 *ptrimmed);
extern int gfs2_fitrim(struct file *filp, void __user *argp);

+/* This is how to tell if a reservation is "inplace" reserved: */
+static inline int gfs2_mb_reserved(struct gfs2_inode *ip)
+{
+ if (ip->i_res && ip->i_res->rs_requested)
+ return 1;
+ return 0;
+}
+
#endif /* __RGRP_DOT_H__ */
diff --git a/fs/gfs2/super.c b/fs/gfs2/super.c
index 6172fa7..a42df66 100644
--- a/fs/gfs2/super.c
+++ b/fs/gfs2/super.c
@@ -1554,6 +1554,7 @@ out_unlock:
out:
/* Case 3 starts here */
truncate_inode_pages(&inode->i_data, 0);
+ gfs2_rs_delete(ip);
end_writeback(inode);
gfs2_dir_hash_inval(ip);
ip->i_gl->gl_object = NULL;
@@ -1576,6 +1577,7 @@ static struct inode *gfs2_alloc_inode(struct super_block *sb)
ip->i_flags = 0;
ip->i_gl = NULL;
ip->i_rgd = NULL;
+ ip->i_res = NULL;
}
return &ip->i_inode;
}
diff --git a/fs/gfs2/trans.h b/fs/gfs2/trans.h
index 125d457..41f42cd 100644
--- a/fs/gfs2/trans.h
+++ b/fs/gfs2/trans.h
@@ -31,7 +31,7 @@ struct gfs2_glock;
static inline unsigned int gfs2_rg_blocks(const struct gfs2_inode *ip)
{
const struct gfs2_blkreserv *rs = ip->i_res;
- if (rs->rs_requested < ip->i_rgd->rd_length)
+ if (rs && rs->rs_requested < ip->i_rgd->rd_length)
return rs->rs_requested + 1;
return ip->i_rgd->rd_length;
}


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