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author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-17 02:20:36 +0400 |
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committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-17 02:20:36 +0400 |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /fs/autofs/dirhash.c | |
download | linux-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.xz |
Linux-2.6.12-rc2v2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Diffstat (limited to 'fs/autofs/dirhash.c')
-rw-r--r-- | fs/autofs/dirhash.c | 249 |
1 files changed, 249 insertions, 0 deletions
diff --git a/fs/autofs/dirhash.c b/fs/autofs/dirhash.c new file mode 100644 index 000000000000..448143fd0796 --- /dev/null +++ b/fs/autofs/dirhash.c @@ -0,0 +1,249 @@ +/* -*- linux-c -*- --------------------------------------------------------- * + * + * linux/fs/autofs/dirhash.c + * + * Copyright 1997-1998 Transmeta Corporation -- All Rights Reserved + * + * This file is part of the Linux kernel and is made available under + * the terms of the GNU General Public License, version 2, or at your + * option, any later version, incorporated herein by reference. + * + * ------------------------------------------------------------------------- */ + +#include "autofs_i.h" + +/* Functions for maintenance of expiry queue */ + +static void autofs_init_usage(struct autofs_dirhash *dh, + struct autofs_dir_ent *ent) +{ + list_add_tail(&ent->exp, &dh->expiry_head); + ent->last_usage = jiffies; +} + +static void autofs_delete_usage(struct autofs_dir_ent *ent) +{ + list_del(&ent->exp); +} + +void autofs_update_usage(struct autofs_dirhash *dh, + struct autofs_dir_ent *ent) +{ + autofs_delete_usage(ent); /* Unlink from current position */ + autofs_init_usage(dh,ent); /* Relink at queue tail */ +} + +struct autofs_dir_ent *autofs_expire(struct super_block *sb, + struct autofs_sb_info *sbi, + struct vfsmount *mnt) +{ + struct autofs_dirhash *dh = &sbi->dirhash; + struct autofs_dir_ent *ent; + struct dentry *dentry; + unsigned long timeout = sbi->exp_timeout; + + while (1) { + if ( list_empty(&dh->expiry_head) || sbi->catatonic ) + return NULL; /* No entries */ + /* We keep the list sorted by last_usage and want old stuff */ + ent = list_entry(dh->expiry_head.next, struct autofs_dir_ent, exp); + if (jiffies - ent->last_usage < timeout) + break; + /* Move to end of list in case expiry isn't desirable */ + autofs_update_usage(dh, ent); + + /* Check to see that entry is expirable */ + if ( ent->ino < AUTOFS_FIRST_DIR_INO ) + return ent; /* Symlinks are always expirable */ + + /* Get the dentry for the autofs subdirectory */ + dentry = ent->dentry; + + if ( !dentry ) { + /* Should only happen in catatonic mode */ + printk("autofs: dentry == NULL but inode range is directory, entry %s\n", ent->name); + autofs_delete_usage(ent); + continue; + } + + if ( !dentry->d_inode ) { + dput(dentry); + printk("autofs: negative dentry on expiry queue: %s\n", + ent->name); + autofs_delete_usage(ent); + continue; + } + + /* Make sure entry is mounted and unused; note that dentry will + point to the mounted-on-top root. */ + if (!S_ISDIR(dentry->d_inode->i_mode)||!d_mountpoint(dentry)) { + DPRINTK(("autofs: not expirable (not a mounted directory): %s\n", ent->name)); + continue; + } + mntget(mnt); + dget(dentry); + if (!follow_down(&mnt, &dentry)) { + dput(dentry); + mntput(mnt); + DPRINTK(("autofs: not expirable (not a mounted directory): %s\n", ent->name)); + continue; + } + while (d_mountpoint(dentry) && follow_down(&mnt, &dentry)) + ; + dput(dentry); + + if ( may_umount(mnt) == 0 ) { + mntput(mnt); + DPRINTK(("autofs: signaling expire on %s\n", ent->name)); + return ent; /* Expirable! */ + } + DPRINTK(("autofs: didn't expire due to may_umount: %s\n", ent->name)); + mntput(mnt); + } + return NULL; /* No expirable entries */ +} + +void autofs_initialize_hash(struct autofs_dirhash *dh) { + memset(&dh->h, 0, AUTOFS_HASH_SIZE*sizeof(struct autofs_dir_ent *)); + INIT_LIST_HEAD(&dh->expiry_head); +} + +struct autofs_dir_ent *autofs_hash_lookup(const struct autofs_dirhash *dh, struct qstr *name) +{ + struct autofs_dir_ent *dhn; + + DPRINTK(("autofs_hash_lookup: hash = 0x%08x, name = ", name->hash)); + autofs_say(name->name,name->len); + + for ( dhn = dh->h[(unsigned) name->hash % AUTOFS_HASH_SIZE] ; dhn ; dhn = dhn->next ) { + if ( name->hash == dhn->hash && + name->len == dhn->len && + !memcmp(name->name, dhn->name, name->len) ) + break; + } + + return dhn; +} + +void autofs_hash_insert(struct autofs_dirhash *dh, struct autofs_dir_ent *ent) +{ + struct autofs_dir_ent **dhnp; + + DPRINTK(("autofs_hash_insert: hash = 0x%08x, name = ", ent->hash)); + autofs_say(ent->name,ent->len); + + autofs_init_usage(dh,ent); + if (ent->dentry) + dget(ent->dentry); + + dhnp = &dh->h[(unsigned) ent->hash % AUTOFS_HASH_SIZE]; + ent->next = *dhnp; + ent->back = dhnp; + *dhnp = ent; + if ( ent->next ) + ent->next->back = &(ent->next); +} + +void autofs_hash_delete(struct autofs_dir_ent *ent) +{ + *(ent->back) = ent->next; + if ( ent->next ) + ent->next->back = ent->back; + + autofs_delete_usage(ent); + + if ( ent->dentry ) + dput(ent->dentry); + kfree(ent->name); + kfree(ent); +} + +/* + * Used by readdir(). We must validate "ptr", so we can't simply make it + * a pointer. Values below 0xffff are reserved; calling with any value + * <= 0x10000 will return the first entry found. + * + * "last" can be NULL or the value returned by the last search *if* we + * want the next sequential entry. + */ +struct autofs_dir_ent *autofs_hash_enum(const struct autofs_dirhash *dh, + off_t *ptr, struct autofs_dir_ent *last) +{ + int bucket, ecount, i; + struct autofs_dir_ent *ent; + + bucket = (*ptr >> 16) - 1; + ecount = *ptr & 0xffff; + + if ( bucket < 0 ) { + bucket = ecount = 0; + } + + DPRINTK(("autofs_hash_enum: bucket %d, entry %d\n", bucket, ecount)); + + ent = last ? last->next : NULL; + + if ( ent ) { + ecount++; + } else { + while ( bucket < AUTOFS_HASH_SIZE ) { + ent = dh->h[bucket]; + for ( i = ecount ; ent && i ; i-- ) + ent = ent->next; + + if (ent) { + ecount++; /* Point to *next* entry */ + break; + } + + bucket++; ecount = 0; + } + } + +#ifdef DEBUG + if ( !ent ) + printk("autofs_hash_enum: nothing found\n"); + else { + printk("autofs_hash_enum: found hash %08x, name", ent->hash); + autofs_say(ent->name,ent->len); + } +#endif + + *ptr = ((bucket+1) << 16) + ecount; + return ent; +} + +/* Iterate over all the ents, and remove all dentry pointers. Used on + entering catatonic mode, in order to make the filesystem unmountable. */ +void autofs_hash_dputall(struct autofs_dirhash *dh) +{ + int i; + struct autofs_dir_ent *ent; + + for ( i = 0 ; i < AUTOFS_HASH_SIZE ; i++ ) { + for ( ent = dh->h[i] ; ent ; ent = ent->next ) { + if ( ent->dentry ) { + dput(ent->dentry); + ent->dentry = NULL; + } + } + } +} + +/* Delete everything. This is used on filesystem destruction, so we + make no attempt to keep the pointers valid */ +void autofs_hash_nuke(struct autofs_dirhash *dh) +{ + int i; + struct autofs_dir_ent *ent, *nent; + + for ( i = 0 ; i < AUTOFS_HASH_SIZE ; i++ ) { + for ( ent = dh->h[i] ; ent ; ent = nent ) { + nent = ent->next; + if ( ent->dentry ) + dput(ent->dentry); + kfree(ent->name); + kfree(ent); + } + } +} |