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ext2fs: add dir_nlink feature support.

Browse Source 
ext4 on linux has always supported more than 32000 directories through
the dir_nlink feature, but FreeBSD was unable to catch up on this feature.
As part of the 64 bit inode changes nlink_t has been extended and this
feature is now possible.

Submitted by:	Fedor Uporov
Differential Revision:	https://reviews.freebsd.org/D11210
This commit is contained in:
Pedro F. Giffuni 2017-06-22 02:43:32 +00:00
parent 3452510890
commit a821bdcfd9
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=320211
4 changed files with 67 additions and 32 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
sys/fs/ext2fs/ext2_dir.h
View File

@ -74,6 +74,7 @@ struct ext2fs_direct_2 {
* Maximal count of links to a file
*/
#define EXT2_LINK_MAX 32000
#define EXT4_LINK_MAX 65000
/*
* Ext2 directory file types. Only the low 3 bits are used. The

95
sys/fs/ext2fs/ext2_vnops.c
View File

@ -672,6 +672,19 @@ ext2_remove(struct vop_remove_args *ap)
return (error);
}
static unsigned short
ext2_max_nlink(struct inode *ip)
{
struct m_ext2fs *fs;
fs = ip->i_e2fs;
if (EXT2_HAS_RO_COMPAT_FEATURE(fs, EXT2F_ROCOMPAT_DIR_NLINK))
return (EXT4_LINK_MAX);
else
return (EXT2_LINK_MAX);
}
/*
* link vnode call
*/
@ -689,7 +702,7 @@ ext2_link(struct vop_link_args *ap)
panic("ext2_link: no name");
#endif
ip = VTOI(vp);
if ((nlink_t)ip->i_nlink >= EXT2_LINK_MAX) {
if ((nlink_t)ip->i_nlink >= ext2_max_nlink(ip)) {
error = EMLINK;
goto out;
}
@ -710,6 +723,31 @@ ext2_link(struct vop_link_args *ap)
return (error);
}
static int
ext2_inc_nlink(struct inode *ip)
{
ip->i_nlink++;
if (ext2_htree_has_idx(ip) && ip->i_nlink > 1) {
if (ip->i_nlink >= ext2_max_nlink(ip) || ip->i_nlink == 2)
ip->i_nlink = 1;
} else if (ip->i_nlink > ext2_max_nlink(ip)) {
ip->i_nlink--;
return (EMLINK);
}
return (0);
}
static void
ext2_dec_nlink(struct inode *ip)
{
if (!S_ISDIR(ip->i_mode) || ip->i_nlink > 2)
ip->i_nlink--;
}
/*
* Rename system call.
* rename("foo", "bar");
@ -792,7 +830,7 @@ ext2_rename(struct vop_rename_args *ap)
goto abortit;
dp = VTOI(fdvp);
ip = VTOI(fvp);
if (ip->i_nlink >= EXT2_LINK_MAX) {
if (ip->i_nlink >= ext2_max_nlink(ip) && !ext2_htree_has_idx(ip)) {
VOP_UNLOCK(fvp, 0);
error = EMLINK;
goto abortit;
@ -835,7 +873,7 @@ ext2_rename(struct vop_rename_args *ap)
* completing our work, the link count
* may be wrong, but correctable.
*/
ip->i_nlink++;
ext2_inc_nlink(ip);
ip->i_flag |= IN_CHANGE;
if ((error = ext2_update(fvp, !DOINGASYNC(fvp))) != 0) {
VOP_UNLOCK(fvp, 0);
@ -890,11 +928,10 @@ ext2_rename(struct vop_rename_args *ap)
* parent we don't fool with the link count.
*/
if (doingdirectory && newparent) {
if ((nlink_t)dp->i_nlink >= EXT2_LINK_MAX) {
error = EMLINK;
error = ext2_inc_nlink(dp);
if (error)
goto bad;
}
dp->i_nlink++;
dp->i_flag |= IN_CHANGE;
error = ext2_update(tdvp, !DOINGASYNC(tdvp));
if (error)
@ -903,7 +940,7 @@ ext2_rename(struct vop_rename_args *ap)
error = ext2_direnter(ip, tdvp, tcnp);
if (error) {
if (doingdirectory && newparent) {
dp->i_nlink--;
ext2_dec_nlink(dp);
dp->i_flag |= IN_CHANGE;
(void)ext2_update(tdvp, 1);
}
@ -936,8 +973,7 @@ ext2_rename(struct vop_rename_args *ap)
* (both directories, or both not directories).
*/
if ((xp->i_mode & IFMT) == IFDIR) {
if (!ext2_dirempty(xp, dp->i_number, tcnp->cn_cred) ||
xp->i_nlink > 2) {
if (!ext2_dirempty(xp, dp->i_number, tcnp->cn_cred)) {
error = ENOTEMPTY;
goto bad;
}
@ -960,7 +996,7 @@ ext2_rename(struct vop_rename_args *ap)
* of the target directory.
*/
if (doingdirectory && !newparent) {
dp->i_nlink--;
ext2_dec_nlink(dp);
dp->i_flag |= IN_CHANGE;
}
vput(tdvp);
@ -974,7 +1010,7 @@ ext2_rename(struct vop_rename_args *ap)
* it above, as the remaining link would point to
* a directory without "." or ".." entries.
*/
xp->i_nlink--;
ext2_dec_nlink(xp);
if (doingdirectory) {
if (--xp->i_nlink != 0)
panic("ext2_rename: linked directory");
@ -1031,7 +1067,7 @@ ext2_rename(struct vop_rename_args *ap)
* and ".." set to point to the new parent.
*/
if (doingdirectory && newparent) {
dp->i_nlink--;
ext2_dec_nlink(dp);
dp->i_flag |= IN_CHANGE;
error = vn_rdwr(UIO_READ, fvp, (caddr_t)&dirbuf,
sizeof(struct dirtemplate), (off_t)0,
@ -1060,7 +1096,7 @@ ext2_rename(struct vop_rename_args *ap)
}
error = ext2_dirremove(fdvp, fcnp);
if (!error) {
xp->i_nlink--;
ext2_dec_nlink(xp);
xp->i_flag |= IN_CHANGE;
}
xp->i_flag &= ~IN_RENAME;
@ -1080,7 +1116,7 @@ ext2_rename(struct vop_rename_args *ap)
if (doingdirectory)
ip->i_flag &= ~IN_RENAME;
if (vn_lock(fvp, LK_EXCLUSIVE) == 0) {
ip->i_nlink--;
ext2_dec_nlink(ip);
ip->i_flag |= IN_CHANGE;
ip->i_flag &= ~IN_RENAME;
vput(fvp);
@ -1255,7 +1291,8 @@ ext2_mkdir(struct vop_mkdir_args *ap)
panic("ext2_mkdir: no name");
#endif
dp = VTOI(dvp);
if ((nlink_t)dp->i_nlink >= EXT2_LINK_MAX) {
if ((nlink_t)dp->i_nlink >= ext2_max_nlink(dp) &&
!ext2_htree_has_idx(dp)) {
error = EMLINK;
goto out;
}
@ -1306,7 +1343,7 @@ ext2_mkdir(struct vop_mkdir_args *ap)
* be done before reference is created
* so reparation is possible if we crash.
*/
dp->i_nlink++;
ext2_inc_nlink(dp);
dp->i_flag |= IN_CHANGE;
error = ext2_update(dvp, !DOINGASYNC(dvp));
if (error)
@ -1333,7 +1370,7 @@ ext2_mkdir(struct vop_mkdir_args *ap)
IO_NODELOCKED | IO_SYNC | IO_NOMACCHECK, cnp->cn_cred, NOCRED,
NULL, NULL);
if (error) {
dp->i_nlink--;
ext2_dec_nlink(dp);
dp->i_flag |= IN_CHANGE;
goto bad;
}
@ -1358,7 +1395,7 @@ ext2_mkdir(struct vop_mkdir_args *ap)
/* Directory set up, now install its entry in the parent directory. */
error = ext2_direnter(ip, dvp, cnp);
if (error) {
dp->i_nlink--;
ext2_dec_nlink(dp);
dp->i_flag |= IN_CHANGE;
}
bad:
@ -1400,7 +1437,7 @@ ext2_rmdir(struct vop_rmdir_args *ap)
* the current directory and thus be
* non-empty.)
*/
if (ip->i_nlink != 2 || !ext2_dirempty(ip, dp->i_number, cnp->cn_cred)) {
if (!ext2_dirempty(ip, dp->i_number, cnp->cn_cred)) {
error = ENOTEMPTY;
goto out;
}
@ -1417,22 +1454,15 @@ ext2_rmdir(struct vop_rmdir_args *ap)
error = ext2_dirremove(dvp, cnp);
if (error)
goto out;
dp->i_nlink--;
ext2_dec_nlink(dp);
dp->i_flag |= IN_CHANGE;
cache_purge(dvp);
VOP_UNLOCK(dvp, 0);
/*
* Truncate inode. The only stuff left
* in the directory is "." and "..". The
* "." reference is inconsequential since
* we're quashing it. The ".." reference
* has already been adjusted above. We've
* removed the "." reference and the reference
* in the parent directory, but there may be
* other hard links so decrement by 2 and
* worry about them later.
* in the directory is "." and "..".
*/
ip->i_nlink -= 2;
ip->i_nlink = 0;
error = ext2_truncate(vp, (off_t)0, IO_SYNC, cnp->cn_cred,
cnp->cn_thread);
cache_purge(ITOV(ip));
@ -1592,7 +1622,10 @@ ext2_pathconf(struct vop_pathconf_args *ap)
switch (ap->a_name) {
case _PC_LINK_MAX:
*ap->a_retval = EXT2_LINK_MAX;
if (ext2_htree_has_idx(VTOI(ap->a_vp)))
*ap->a_retval = INT_MAX;
else
*ap->a_retval = ext2_max_nlink(VTOI(ap->a_vp));
break;
case _PC_NAME_MAX:
*ap->a_retval = NAME_MAX;

1
sys/fs/ext2fs/ext2fs.h
View File

@ -260,6 +260,7 @@ struct csum {
#define EXT2F_ROCOMPAT_SUPP (EXT2F_ROCOMPAT_SPARSESUPER | \
EXT2F_ROCOMPAT_LARGEFILE | \
EXT2F_ROCOMPAT_GDT_CSUM | \
EXT2F_ROCOMPAT_DIR_NLINK | \
EXT2F_ROCOMPAT_HUGE_FILE | \
EXT2F_ROCOMPAT_EXTRA_ISIZE)
#define EXT2F_INCOMPAT_SUPP EXT2F_INCOMPAT_FTYPE

2
sys/fs/ext2fs/inode.h
View File

@ -91,7 +91,7 @@ struct inode {
/* Fields from struct dinode in UFS. */
uint16_t i_mode; /* IFMT, permissions; see below. */
int16_t i_nlink; /* File link count. */
int32_t i_nlink; /* File link count. */
uint32_t i_uid; /* File owner. */
uint32_t i_gid; /* File group. */
uint64_t i_size; /* File byte count. */