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SubjectRe: [reiserfs-dev] Re: [PATCH] sparc32: wrong type of nlink_t
Date
Here's the JFS patch.  When I first saw this thread I didn't expect that
the result would be increasing the max. number of links. :^)

Note that I made JFS_LINK_MAX the maximum supported by JFS,
and VFS_LINK_MAX as the number limited by the size of nlink_t.
VFS_LINK_MAX could be moved to fs.h if other file systems are
to use it in the same way.

I borrowed reiserfs's *_INODE_NLINK macros, but made them inline functions.

(I don't usually send patches from kmail. I hope it doesn't screw up the formatting.)

===== fs/jfs/jfs_filsys.h 1.1 vs edited =====
--- 1.1/fs/jfs/jfs_filsys.h Fri May 31 08:19:24 2002
+++ edited/fs/jfs/jfs_filsys.h Thu Sep 5 11:01:55 2002
@@ -125,7 +125,13 @@
#define MAXBLOCKSIZE 4096
#define MAXFILESIZE ((s64)1 << 52)

-#define JFS_LINK_MAX 65535 /* nlink_t is unsigned short */
+/*
+ * The max link count in struct inode is limited to the size of nlink_t.
+ * The JFS inode uses an unsigned 32-bit int, so we can really go higher
+ */
+#define JFS_LINK_MAX 0xffffffff /* real limit */
+#define VFS_LINK_MAX ((((nlink_t) -1) > 0) ? (nlink_t) ~0 : \
+ ((1u << (sizeof (nlink_t) * 8 - 1)) -1))

/* Minimum number of bytes supported for a JFS partition */
#define MINJFS (0x1000000)
===== fs/jfs/jfs_imap.c 1.6 vs edited =====
--- 1.6/fs/jfs/jfs_imap.c Wed Sep 4 11:11:52 2002
+++ edited/fs/jfs/jfs_imap.c Thu Sep 5 10:52:53 2002
@@ -3035,7 +3035,15 @@
jfs_ip->mode2 = le32_to_cpu(dip->di_mode);

ip->i_mode = le32_to_cpu(dip->di_mode) & 0xffff;
- ip->i_nlink = le32_to_cpu(dip->di_nlink);
+
+ jfs_ip->nlink_real = le32_to_cpu(dip->di_nlink);
+ if (jfs_ip->nlink_real <= VFS_LINK_MAX)
+ ip->i_nlink = jfs_ip->nlink_real;
+ else if (S_ISDIR(ip->i_mode))
+ ip->i_nlink = 1;
+ else
+ ip->i_nlink = VFS_LINK_MAX;
+
ip->i_uid = le32_to_cpu(dip->di_uid);
ip->i_gid = le32_to_cpu(dip->di_gid);
ip->i_size = le64_to_cpu(dip->di_size);
@@ -3089,7 +3097,7 @@
dip->di_gen = cpu_to_le32(ip->i_generation);
dip->di_size = cpu_to_le64(ip->i_size);
dip->di_nblocks = cpu_to_le64(PBLK2LBLK(ip->i_sb, ip->i_blocks));
- dip->di_nlink = cpu_to_le32(ip->i_nlink);
+ dip->di_nlink = cpu_to_le32(jfs_ip->nlink_real);
dip->di_uid = cpu_to_le32(ip->i_uid);
dip->di_gid = cpu_to_le32(ip->i_gid);
/*
===== fs/jfs/jfs_incore.h 1.5 vs edited =====
--- 1.5/fs/jfs/jfs_incore.h Mon Sep 2 05:48:42 2002
+++ edited/fs/jfs/jfs_incore.h Thu Sep 5 10:12:09 2002
@@ -38,6 +38,7 @@
struct inode *inode; /* pointer back to fs-independent inode */
int fileset; /* fileset number (always 16)*/
uint mode2; /* jfs-specific mode */
+ uint nlink_real; /* i_nlink is too short */
pxd_t ixpxd; /* inode extent descriptor */
dxd_t acl; /* dxd describing acl */
dxd_t ea; /* dxd describing ea */
===== fs/jfs/namei.c 1.9 vs edited =====
--- 1.9/fs/jfs/namei.c Mon Aug 26 14:07:42 2002
+++ edited/fs/jfs/namei.c Thu Sep 5 11:11:57 2002
@@ -44,6 +44,34 @@
s64 commitZeroLink(tid_t, struct inode *);

/*
+ * i_nlink accounting
+ * Keep track of real link count, while keeping i_nlink, which may be too
+ * small to hold the real value, sane.
+ */
+static inline void INC_INODE_NLINK(struct inode *inode)
+{
+ if (++JFS_IP(inode)->nlink_real <= VFS_LINK_MAX)
+ inode->i_nlink = JFS_IP(inode)->nlink_real;
+}
+static inline void DEC_INODE_NLINK(struct inode *inode)
+{
+ if (--JFS_IP(inode)->nlink_real <= VFS_LINK_MAX)
+ inode->i_nlink = JFS_IP(inode)->nlink_real;
+}
+/*
+ * Due to an optimazation in the find command (and other cases?),
+ * set i_nlink to one if i_nlink can't be correct.
+ */
+static inline void INC_DIR_INODE_NLINK(struct inode *inode)
+{
+ if (++JFS_IP(inode)->nlink_real <= VFS_LINK_MAX)
+ inode->i_nlink = JFS_IP(inode)->nlink_real;
+ else
+ inode->i_nlink = 1;
+}
+#define DEC_DIR_INODE_NLINK DEC_INODE_NLINK
+
+/*
* NAME: jfs_create(dip, dentry, mode)
*
* FUNCTION: create a regular file in the parent directory <dip>
@@ -142,7 +170,7 @@
up(&JFS_IP(dip)->commit_sem);
up(&JFS_IP(ip)->commit_sem);
if (rc) {
- ip->i_nlink = 0;
+ ip->i_nlink = JFS_IP(ip)->nlink_real = 0;
iput(ip);
}

@@ -185,7 +213,7 @@
jFYI(1, ("jfs_mkdir: dip:0x%p name:%s\n", dip, dentry->d_name.name));

/* link count overflow on parent directory ? */
- if (dip->i_nlink == JFS_LINK_MAX) {
+ if (JFS_IP(dip)->nlink_real == JFS_LINK_MAX) {
rc = EMLINK;
goto out1;
}
@@ -245,7 +273,7 @@
goto out3;
}

- ip->i_nlink = 2; /* for '.' */
+ ip->i_nlink = JFS_IP(ip)->nlink_real = 2; /* for '.' */
ip->i_op = &jfs_dir_inode_operations;
ip->i_fop = &jfs_dir_operations;
ip->i_mapping->a_ops = &jfs_aops;
@@ -256,7 +284,7 @@
d_instantiate(dentry, ip);

/* update parent directory inode */
- dip->i_nlink++; /* for '..' from child directory */
+ INC_DIR_INODE_NLINK(dip); /* for '..' from child directory */
dip->i_ctime = dip->i_mtime = CURRENT_TIME;
mark_inode_dirty(dip);

@@ -267,7 +295,7 @@
up(&JFS_IP(dip)->commit_sem);
up(&JFS_IP(ip)->commit_sem);
if (rc) {
- ip->i_nlink = 0;
+ ip->i_nlink = JFS_IP(ip)->nlink_real = 0;
iput(ip);
}

@@ -351,7 +379,7 @@
/* update parent directory's link count corresponding
* to ".." entry of the target directory deleted
*/
- dip->i_nlink--;
+ DEC_DIR_INODE_NLINK(dip);
dip->i_ctime = dip->i_mtime = CURRENT_TIME;
mark_inode_dirty(dip);

@@ -373,7 +401,7 @@
JFS_IP(ip)->acl.flag = 0;

/* mark the target directory as deleted */
- ip->i_nlink = 0;
+ ip->i_nlink = JFS_IP(ip)->nlink_real = 0;
mark_inode_dirty(ip);

rc = txCommit(tid, 2, &iplist[0], 0);
@@ -470,7 +498,7 @@
mark_inode_dirty(dip);

/* update target's inode */
- ip->i_nlink--;
+ DEC_INODE_NLINK(ip);
mark_inode_dirty(ip);

/*
@@ -768,7 +796,7 @@
down(&JFS_IP(dir)->commit_sem);
down(&JFS_IP(ip)->commit_sem);

- if (ip->i_nlink == JFS_LINK_MAX) {
+ if (JFS_IP(ip)->nlink_real == JFS_LINK_MAX) {
rc = EMLINK;
goto out;
}
@@ -790,7 +818,7 @@
goto out;

/* update object inode */
- ip->i_nlink++; /* for new link */
+ INC_INODE_NLINK(ip);
ip->i_ctime = CURRENT_TIME;
mark_inode_dirty(dir);
atomic_inc(&ip->i_count);
@@ -1004,7 +1032,7 @@
up(&JFS_IP(dip)->commit_sem);
up(&JFS_IP(ip)->commit_sem);
if (rc) {
- ip->i_nlink = 0;
+ ip->i_nlink = JFS_IP(ip)->nlink_real = 0;
iput(ip);
}

@@ -1091,7 +1119,7 @@
goto out3;
}
} else if ((new_dir != old_dir) &&
- (new_dir->i_nlink == JFS_LINK_MAX)) {
+ (JFS_IP(new_dir)->nlink_real == JFS_LINK_MAX)) {
rc = EMLINK;
goto out3;
}
@@ -1118,9 +1146,9 @@
old_ip->i_ino, JFS_RENAME);
if (rc)
goto out4;
- new_ip->i_nlink--;
+ DEC_INODE_NLINK(new_ip);
if (S_ISDIR(new_ip->i_mode)) {
- new_ip->i_nlink--;
+ DEC_DIR_INODE_NLINK(new_ip);
assert(new_ip->i_nlink == 0);
tblk = tid_to_tblock(tid);
tblk->xflag |= COMMIT_DELETE;
@@ -1162,7 +1190,7 @@
goto out4;
}
if (S_ISDIR(old_ip->i_mode))
- new_dir->i_nlink++;
+ INC_DIR_INODE_NLINK(new_dir);
}
/*
* Remove old directory entry
@@ -1178,7 +1206,7 @@
goto out4;
}
if (S_ISDIR(old_ip->i_mode)) {
- old_dir->i_nlink--;
+ DEC_DIR_INODE_NLINK(old_dir);
if (old_dir != new_dir) {
/*
* Change inode number of parent for moved directory
@@ -1351,7 +1379,7 @@
up(&JFS_IP(ip)->commit_sem);
up(&JFS_IP(dir)->commit_sem);
if (rc) {
- ip->i_nlink = 0;
+ ip->i_nlink = JFS_IP(ip)->nlink_real = 0;
iput(ip);
}


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