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XFS: remove i_gen from incore inode

PATCH In review Dave Chinner 2 participants 8 messages Jul 20, 2008 – Nov 21, 2008 XFS filesystem

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#0 lore raw

PATCH 1/1 XFS: remove i_gen from incore inode

i_gen is incremented in directory operations when the directory is changed. It is never read or otherwise used so it should be removed to help reduce the size of the struct xfs_inode.

---
 fs/xfs/xfs_inode.h    |    1 -
 fs/xfs/xfs_rename.c   |   12 ++----------
 fs/xfs/xfs_vnodeops.c |   29 ++---------------------------
 3 files changed, 4 insertions(+), 38 deletions(-)
fs/xfs/xfs_inode.h +0 -1
index 440b443..316c374 100644
@@ -223,7 +223,6 @@ typedef struct xfs_inode {
 	unsigned short		i_flags;	/* see defined flags below */
 	unsigned char		i_update_core;	/* timestamps/size is dirty */
 	unsigned char		i_update_size;	/* di_size field is dirty */
-	unsigned int		i_gen;		/* generation count */
 	unsigned int		i_delayed_blks;	/* count of delay alloc blks */
 
 	xfs_icdinode_t		i_d;		/* most of ondisk inode */
fs/xfs/xfs_rename.c +2 -10
index d700dac..02f0e8f 100644
@@ -367,19 +367,11 @@ xfs_rename(
 					&first_block, &free_list, spaceres);
 	if (error)
 		goto abort_return;
-	xfs_ichgtime(src_dp, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
 
-	/*
-	 * Update the generation counts on all the directory inodes
-	 * that we're modifying.
-	 */
-	src_dp->i_gen++;
+	xfs_ichgtime(src_dp, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
 	xfs_trans_log_inode(tp, src_dp, XFS_ILOG_CORE);
-
-	if (new_parent) {
-		target_dp->i_gen++;
+	if (new_parent)
 		xfs_trans_log_inode(tp, target_dp, XFS_ILOG_CORE);
-	}
 
 	/*
 	 * If this is a synchronous mount, make sure that the
fs/xfs/xfs_vnodeops.c +2 -27
index cca2871..36bf85c 100644
@@ -1619,8 +1619,6 @@ xfs_create(
 		xfs_trans_set_sync(tp);
 	}
 
-	dp->i_gen++;
-
 	/*
 	 * Attach the dquot(s) to the inodes and modify them incore.
 	 * These ids of the inode couldn't have changed since the new
@@ -2050,13 +2048,6 @@ xfs_remove(
 	}
 	xfs_ichgtime(dp, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
 
-	/*
-	 * Bump the in memory generation count on the parent
-	 * directory so that other can know that it has changed.
-	 */
-	dp->i_gen++;
-	xfs_trans_log_inode(tp, dp, XFS_ILOG_CORE);
-
 	if (is_dir) {
 		/*
 		 * Drop the link from ip's "..".
@@ -2074,8 +2065,8 @@ xfs_remove(
 	} else {
 		/*
 		 * When removing a non-directory we need to log the parent
-		 * inode here for the i_gen update.  For a directory this is
-		 * done implicitly by the xfs_droplink call for the ".." entry.
+		 * inode here.  For a directory this is done implicitly
+		 * by the xfs_droplink call for the ".." entry.
 		 */
 		xfs_trans_log_inode(tp, dp, XFS_ILOG_CORE);
 	}
@@ -2244,7 +2235,6 @@ xfs_link(
 	if (error)
 		goto abort_return;
 	xfs_ichgtime(tdp, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
-	tdp->i_gen++;
 	xfs_trans_log_inode(tp, tdp, XFS_ILOG_CORE);
 
 	error = xfs_bumplink(tp, sip);
@@ -2421,18 +2411,10 @@ xfs_mkdir(
 	}
 	xfs_ichgtime(dp, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
 
-	/*
-	 * Bump the in memory version number of the parent directory
-	 * so that other processes accessing it will recognize that
-	 * the directory has changed.
-	 */
-	dp->i_gen++;
-
 	error = xfs_dir_init(tp, cdp, dp);
 	if (error)
 		goto error2;
 
-	cdp->i_gen = 1;
 	error = xfs_bumplink(tp, dp);
 	if (error)
 		goto error2;
@@ -2719,13 +2701,6 @@ xfs_symlink(
 	xfs_trans_log_inode(tp, dp, XFS_ILOG_CORE);
 
 	/*
-	 * Bump the in memory version number of the parent directory
-	 * so that other processes accessing it will recognize that
-	 * the directory has changed.
-	 */
-	dp->i_gen++;
-
-	/*
 	 * If this is a synchronous mount, make sure that the
 	 * symlink transaction goes to disk before returning to
 	 * the user.
Signature · 1 line
1.5.6
#1 lore raw
Quoted 4 lines · Dave Chinner

i_gen is incremented in directory operations when the directory is changed. It is never read or otherwise used so it should be removed to help reduce the size of the struct xfs_inode.

It also removes a xfs_trans_log_inode in xfs_remove, which looks fine to me from a quick glance, but this should be verified and documented.

Otherwise looks good.

#2 lore raw
Quoted 9 lines · Christoph Hellwig
Quoted 4 lines · Dave Chinner

i_gen is incremented in directory operations when the directory is changed. It is never read or otherwise used so it should be removed to help reduce the size of the struct xfs_inode.

It also removes a xfs_trans_log_inode in xfs_remove, which looks fine to me from a quick glance, but this should be verified and documented.

If you note in the very next if/else statement the directory inode gets logged - either by dropping the link or directly. IOWs, we were logging the directory inode twice with the same value (XFS_ILOG_CORE). So I don't think thereśs any problem here.

Cheers,

Dave.

Signature · 2 lines
Dave Chinner
[email protected]
#3 lore raw
Quoted 7 lines · Dave Chinner
Quoted 6 lines · Christoph Hellwig
Quoted 4 lines · Dave Chinner

i_gen is incremented in directory operations when the directory is changed. It is never read or otherwise used so it should be removed to help reduce the size of the struct xfs_inode.

Quoted 8 lines
Quoted 3 lines

It also removes a xfs_trans_log_inode in xfs_remove, which looks fine to me from a quick glance, but this should be verified and documented.

If you note in the very next if/else statement the directory inode gets logged - either by dropping the link or directly. IOWs, we were logging the directory inode twice with the same value (XFS_ILOG_CORE). So I don't think there??s any problem here.

Indeed. The patch looks good but a little description like the one above in the commit message would be nice.

#4 lore raw
Quoted 12 lines · Christoph Hellwig
Quoted 11 lines · Dave Chinner
Quoted 9 lines · Christoph Hellwig
Quoted 4 lines · Dave Chinner

i_gen is incremented in directory operations when the directory is changed. It is never read or otherwise used so it should be removed to help reduce the size of the struct xfs_inode.

It also removes a xfs_trans_log_inode in xfs_remove, which looks fine to me from a quick glance, but this should be verified and documented.

Quoted 7 lines
Quoted 4 lines

If you note in the very next if/else statement the directory inode gets logged - either by dropping the link or directly. IOWs, we were logging the directory inode twice with the same value (XFS_ILOG_CORE). So I don't think there??s any problem here.

Indeed. The patch looks good but a little description like the one above in the commit message would be nice.

Updated patch below.

Cheers,

Dave.

Signature · 21 lines
Dave Chinner
[email protected]


XFS: remove i_gen from incore inode

i_gen is incremented in directory operations when the
directory is changed. It is never read or otherwise used
so it should be removed to help reduce the size of the
struct xfs_inode.

The patch also removes a duplicate logging of the directory
inode core. We only need to do this once per transaction
so kill the one associated with the i_gen increment.

Signed-off-by: Dave Chinner <[email protected]>
---
 fs/xfs/xfs_inode.h    |    1 -
 fs/xfs/xfs_rename.c   |   12 ++----------
 fs/xfs/xfs_vnodeops.c |   29 ++---------------------------
 3 files changed, 4 insertions(+), 38 deletions(-)
fs/xfs/xfs_inode.h +0 -1
index 440b443..316c374 100644
@@ -223,7 +223,6 @@ typedef struct xfs_inode {
 	unsigned short		i_flags;	/* see defined flags below */
 	unsigned char		i_update_core;	/* timestamps/size is dirty */
 	unsigned char		i_update_size;	/* di_size field is dirty */
-	unsigned int		i_gen;		/* generation count */
 	unsigned int		i_delayed_blks;	/* count of delay alloc blks */
 
 	xfs_icdinode_t		i_d;		/* most of ondisk inode */
fs/xfs/xfs_rename.c +2 -10
index d700dac..02f0e8f 100644
@@ -367,19 +367,11 @@ xfs_rename(
 					&first_block, &free_list, spaceres);
 	if (error)
 		goto abort_return;
-	xfs_ichgtime(src_dp, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
 
-	/*
-	 * Update the generation counts on all the directory inodes
-	 * that we're modifying.
-	 */
-	src_dp->i_gen++;
+	xfs_ichgtime(src_dp, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
 	xfs_trans_log_inode(tp, src_dp, XFS_ILOG_CORE);
-
-	if (new_parent) {
-		target_dp->i_gen++;
+	if (new_parent)
 		xfs_trans_log_inode(tp, target_dp, XFS_ILOG_CORE);
-	}
 
 	/*
 	 * If this is a synchronous mount, make sure that the
fs/xfs/xfs_vnodeops.c +2 -27
index 94ec74b..426c574 100644
@@ -1798,8 +1798,6 @@ xfs_create(
 		xfs_trans_set_sync(tp);
 	}
 
-	dp->i_gen++;
-
 	/*
 	 * Attach the dquot(s) to the inodes and modify them incore.
 	 * These ids of the inode couldn't have changed since the new
@@ -2229,13 +2227,6 @@ xfs_remove(
 	}
 	xfs_ichgtime(dp, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
 
-	/*
-	 * Bump the in memory generation count on the parent
-	 * directory so that other can know that it has changed.
-	 */
-	dp->i_gen++;
-	xfs_trans_log_inode(tp, dp, XFS_ILOG_CORE);
-
 	if (is_dir) {
 		/*
 		 * Drop the link from ip's "..".
@@ -2253,8 +2244,8 @@ xfs_remove(
 	} else {
 		/*
 		 * When removing a non-directory we need to log the parent
-		 * inode here for the i_gen update.  For a directory this is
-		 * done implicitly by the xfs_droplink call for the ".." entry.
+		 * inode here.  For a directory this is done implicitly
+		 * by the xfs_droplink call for the ".." entry.
 		 */
 		xfs_trans_log_inode(tp, dp, XFS_ILOG_CORE);
 	}
@@ -2423,7 +2414,6 @@ xfs_link(
 	if (error)
 		goto abort_return;
 	xfs_ichgtime(tdp, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
-	tdp->i_gen++;
 	xfs_trans_log_inode(tp, tdp, XFS_ILOG_CORE);
 
 	error = xfs_bumplink(tp, sip);
@@ -2600,18 +2590,10 @@ xfs_mkdir(
 	}
 	xfs_ichgtime(dp, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
 
-	/*
-	 * Bump the in memory version number of the parent directory
-	 * so that other processes accessing it will recognize that
-	 * the directory has changed.
-	 */
-	dp->i_gen++;
-
 	error = xfs_dir_init(tp, cdp, dp);
 	if (error)
 		goto error2;
 
-	cdp->i_gen = 1;
 	error = xfs_bumplink(tp, dp);
 	if (error)
 		goto error2;
@@ -2898,13 +2880,6 @@ xfs_symlink(
 	xfs_trans_log_inode(tp, dp, XFS_ILOG_CORE);
 
 	/*
-	 * Bump the in memory version number of the parent directory
-	 * so that other processes accessing it will recognize that
-	 * the directory has changed.
-	 */
-	dp->i_gen++;
-
-	/*
 	 * If this is a synchronous mount, make sure that the
 	 * symlink transaction goes to disk before returning to
 	 * the user.
#6 lore raw
In reply to Dave Chinner
Quoted 4 lines · Dave Chinner
Quoted 2 lines

Indeed. The patch looks good but a little description like the one above in the commit message would be nice.

Updated patch below.

Missing the needed xfsidbg changes. Updated version below:

fs/xfs/xfs_inode.h +0 -1
Index: linux-2.6-xfs/fs/xfs/xfs_inode.h
===================================================================
@@ -230,7 +230,6 @@ typedef struct xfs_inode {
 	unsigned short		i_flags;	/* see defined flags below */
 	unsigned char		i_update_core;	/* timestamps/size is dirty */
 	unsigned char		i_update_size;	/* di_size field is dirty */
-	unsigned int		i_gen;		/* generation count */
 	unsigned int		i_delayed_blks;	/* count of delay alloc blks */
 
 	xfs_icdinode_t		i_d;		/* most of ondisk inode */
fs/xfs/xfs_rename.c +2 -10
Index: linux-2.6-xfs/fs/xfs/xfs_rename.c
===================================================================
@@ -367,19 +367,11 @@ xfs_rename(
 					&first_block, &free_list, spaceres);
 	if (error)
 		goto abort_return;
-	xfs_ichgtime(src_dp, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
 
-	/*
-	 * Update the generation counts on all the directory inodes
-	 * that we're modifying.
-	 */
-	src_dp->i_gen++;
+	xfs_ichgtime(src_dp, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
 	xfs_trans_log_inode(tp, src_dp, XFS_ILOG_CORE);
-
-	if (new_parent) {
-		target_dp->i_gen++;
+	if (new_parent)
 		xfs_trans_log_inode(tp, target_dp, XFS_ILOG_CORE);
-	}
 
 	/*
 	 * If this is a synchronous mount, make sure that the
fs/xfs/xfs_vnodeops.c +2 -27
Index: linux-2.6-xfs/fs/xfs/xfs_vnodeops.c
===================================================================
@@ -1625,8 +1625,6 @@ xfs_create(
 		xfs_trans_set_sync(tp);
 	}
 
-	dp->i_gen++;
-
 	/*
 	 * Attach the dquot(s) to the inodes and modify them incore.
 	 * These ids of the inode couldn't have changed since the new
@@ -1985,13 +1983,6 @@ xfs_remove(
 	}
 	xfs_ichgtime(dp, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
 
-	/*
-	 * Bump the in memory generation count on the parent
-	 * directory so that other can know that it has changed.
-	 */
-	dp->i_gen++;
-	xfs_trans_log_inode(tp, dp, XFS_ILOG_CORE);
-
 	if (is_dir) {
 		/*
 		 * Drop the link from ip's "..".
@@ -2009,8 +2000,8 @@ xfs_remove(
 	} else {
 		/*
 		 * When removing a non-directory we need to log the parent
-		 * inode here for the i_gen update.  For a directory this is
-		 * done implicitly by the xfs_droplink call for the ".." entry.
+		 * inode here.  For a directory this is done implicitly
+		 * by the xfs_droplink call for the ".." entry.
 		 */
 		xfs_trans_log_inode(tp, dp, XFS_ILOG_CORE);
 	}
@@ -2170,7 +2161,6 @@ xfs_link(
 	if (error)
 		goto abort_return;
 	xfs_ichgtime(tdp, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
-	tdp->i_gen++;
 	xfs_trans_log_inode(tp, tdp, XFS_ILOG_CORE);
 
 	error = xfs_bumplink(tp, sip);
@@ -2347,18 +2337,10 @@ xfs_mkdir(
 	}
 	xfs_ichgtime(dp, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
 
-	/*
-	 * Bump the in memory version number of the parent directory
-	 * so that other processes accessing it will recognize that
-	 * the directory has changed.
-	 */
-	dp->i_gen++;
-
 	error = xfs_dir_init(tp, cdp, dp);
 	if (error)
 		goto error2;
 
-	cdp->i_gen = 1;
 	error = xfs_bumplink(tp, dp);
 	if (error)
 		goto error2;
@@ -2645,13 +2627,6 @@ xfs_symlink(
 	xfs_trans_log_inode(tp, dp, XFS_ILOG_CORE);
 
 	/*
-	 * Bump the in memory version number of the parent directory
-	 * so that other processes accessing it will recognize that
-	 * the directory has changed.
-	 */
-	dp->i_gen++;
-
-	/*
 	 * If this is a synchronous mount, make sure that the
 	 * symlink transaction goes to disk before returning to
 	 * the user.
fs/xfs/xfsidbg.c +2 -6
Index: linux-2.6-xfs/fs/xfs/xfsidbg.c
===================================================================
@@ -3633,7 +3633,6 @@ xfs_prdinode_incore(xfs_icdinode_t *dip)
 		xfs_fmtformat((xfs_dinode_fmt_t)dip->di_aformat),
 		dip->di_dmevmask, dip->di_dmstate);
 	printflags(dip->di_flags, diflags, "flags");
-	kdb_printf("gen 0x%x\n", dip->di_gen);
 }
 
 #ifdef XFS_RW_TRACE
@@ -6385,11 +6384,8 @@ xfsidbg_xnode(xfs_inode_t *ip)
 	kdb_printf("\n");
 	kdb_printf("update_core %d update size %d\n",
 		(int)(ip->i_update_core), (int) ip->i_update_size);
-	kdb_printf("gen 0x%x delayed blks %d",
-		ip->i_gen,
-		ip->i_delayed_blks);
-	kdb_printf("size %lld\n",
-		ip->i_size);
+	kdb_printf("delayed blks %d size %lld\n",
+		ip->i_delayed_blks, ip->i_size);
 
 #ifdef	XFS_INODE_TRACE
 	qprintf(" trace 0x%p\n", ip->i_trace);
#7 lore raw
In reply to Dave Chinner

Any chance we can get this patch in? It's been out for exactly 4 month in it's final reviewed form, and I still have patches that I rebased on top of it waiting..

Quoted 127 lines · Dave Chinner

XFS: remove i_gen from incore inode

i_gen is incremented in directory operations when the directory is changed. It is never read or otherwise used so it should be removed to help reduce the size of the struct xfs_inode.

The patch also removes a duplicate logging of the directory inode core. We only need to do this once per transaction so kill the one associated with the i_gen increment.

---
 fs/xfs/xfs_inode.h    |    1 -
 fs/xfs/xfs_rename.c   |   12 ++----------
 fs/xfs/xfs_vnodeops.c |   29 ++---------------------------
 3 files changed, 4 insertions(+), 38 deletions(-)
fs/xfs/xfs_inode.h +0 -1
index 440b443..316c374 100644
@@ -223,7 +223,6 @@ typedef struct xfs_inode {
 	unsigned short		i_flags;	/* see defined flags below */
 	unsigned char		i_update_core;	/* timestamps/size is dirty */
 	unsigned char		i_update_size;	/* di_size field is dirty */
-	unsigned int		i_gen;		/* generation count */
 	unsigned int		i_delayed_blks;	/* count of delay alloc blks */
 
 	xfs_icdinode_t		i_d;		/* most of ondisk inode */
fs/xfs/xfs_rename.c +2 -10
index d700dac..02f0e8f 100644
@@ -367,19 +367,11 @@ xfs_rename(
 					&first_block, &free_list, spaceres);
 	if (error)
 		goto abort_return;
-	xfs_ichgtime(src_dp, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
 
-	/*
-	 * Update the generation counts on all the directory inodes
-	 * that we're modifying.
-	 */
-	src_dp->i_gen++;
+	xfs_ichgtime(src_dp, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
 	xfs_trans_log_inode(tp, src_dp, XFS_ILOG_CORE);
-
-	if (new_parent) {
-		target_dp->i_gen++;
+	if (new_parent)
 		xfs_trans_log_inode(tp, target_dp, XFS_ILOG_CORE);
-	}
 
 	/*
 	 * If this is a synchronous mount, make sure that the
fs/xfs/xfs_vnodeops.c +2 -20
index 94ec74b..426c574 100644
@@ -1798,8 +1798,6 @@ xfs_create(
 		xfs_trans_set_sync(tp);
 	}
 
-	dp->i_gen++;
-
 	/*
 	 * Attach the dquot(s) to the inodes and modify them incore.
 	 * These ids of the inode couldn't have changed since the new
@@ -2229,13 +2227,6 @@ xfs_remove(
 	}
 	xfs_ichgtime(dp, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
 
-	/*
-	 * Bump the in memory generation count on the parent
-	 * directory so that other can know that it has changed.
-	 */
-	dp->i_gen++;
-	xfs_trans_log_inode(tp, dp, XFS_ILOG_CORE);
-
 	if (is_dir) {
 		/*
 		 * Drop the link from ip's "..".
@@ -2253,8 +2244,8 @@ xfs_remove(
 	} else {
 		/*
 		 * When removing a non-directory we need to log the parent
-		 * inode here for the i_gen update.  For a directory this is
-		 * done implicitly by the xfs_droplink call for the ".." entry.
+		 * inode here.  For a directory this is done implicitly
+		 * by the xfs_droplink call for the ".." entry.
 		 */
 		xfs_trans_log_inode(tp, dp, XFS_ILOG_CORE);
 	}
@@ -2423,7 +2414,6 @@ xfs_link(
 	if (error)
 		goto abort_return;
 	xfs_ichgtime(tdp, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
-	tdp->i_gen++;
 	xfs_trans_log_inode(tp, tdp, XFS_ILOG_CORE);
 
 	error = xfs_bumplink(tp, sip);
@@ -2600,18 +2590,10 @@ xfs_mkdir(
 	}
 	xfs_ichgtime(dp, XFS_ICHGTIME_MOD | XFS_ICHGTIME_CHG);
 
-	/*
-	 * Bump the in memory version number of the parent directory
-	 * so that other processes accessing it will recognize that
-	 * the directory has changed.
-	 */
-	dp->i_gen++;
-
 	error = xfs_dir_init(tp, cdp, dp);
 	if (error)
 		goto error2;
 
-	cdp->i_gen = 1;
 	error = xfs_bumplink(tp, dp);
 	if (error)
 		goto error2;
@@ -2898,13 +2880,6 @@ xfs_symlink(
 	xfs_trans_log_inode(tp, dp, XFS_ILOG_CORE);
 
 	/*

fs/xfs/xfs_vnodeops.c xfs_symlink( · line 2885

Quoted 10 lines
fs/xfs/xfs_vnodeops.c +0 -7
-	 * Bump the in memory version number of the parent directory
-	 * so that other processes accessing it will recognize that
-	 * the directory has changed.
-	 */
-	dp->i_gen++;
-
-	/*
 	 * If this is a synchronous mount, make sure that the
 	 * symlink transaction goes to disk before returning to
 	 * the user.

---end quoted text---

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