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NTFS: Change ntfs_map_runlist_nolock() to also take an optional attribute

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search context.  This allows calling it with the mft record mapped.

Signed-off-by: Anton Altaparmakov <aia21@cantab.net>
This commit is contained in:
Anton Altaparmakov 2005-10-04 13:44:48 +01:00
parent c394e458b6
commit fd9d63678d
4 changed files with 209 additions and 33 deletions
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5
fs/ntfs/ChangeLog
View file

@ -22,6 +22,11 @@ ToDo/Notes:
- Enable the code for setting the NT4 compatibility flag when we start
making NTFS 1.2 specific modifications.
2.1.25-WIP
- Change ntfs_map_runlist_nolock() to also take an optional attribute
search context. This allows calling it with the mft record mapped.
2.1.24 - Lots of bug fixes and support more clean journal states.
- Support journals ($LogFile) which have been modified by chkdsk. This

2
fs/ntfs/Makefile
View file

@ -6,7 +6,7 @@ ntfs-objs := aops.o attrib.o collate.o compress.o debug.o dir.o file.o \
index.o inode.o mft.o mst.o namei.o runlist.o super.o sysctl.o \
unistr.o upcase.o
EXTRA_CFLAGS = -DNTFS_VERSION=\"2.1.24\"
EXTRA_CFLAGS = -DNTFS_VERSION=\"2.1.25-WIP\"
ifeq ($(CONFIG_NTFS_DEBUG),y)
EXTRA_CFLAGS += -DDEBUG

232
fs/ntfs/attrib.c
View file

@ -36,9 +36,27 @@
* ntfs_map_runlist_nolock - map (a part of) a runlist of an ntfs inode
* @ni: ntfs inode for which to map (part of) a runlist
* @vcn: map runlist part containing this vcn
* @ctx: active attribute search context if present or NULL if not
*
* Map the part of a runlist containing the @vcn of the ntfs inode @ni.
*
* If @ctx is specified, it is an active search context of @ni and its base mft
* record. This is needed when ntfs_map_runlist_nolock() encounters unmapped
* runlist fragments and allows their mapping. If you do not have the mft
* record mapped, you can specify @ctx as NULL and ntfs_map_runlist_nolock()
* will perform the necessary mapping and unmapping.
*
* Note, ntfs_map_runlist_nolock() saves the state of @ctx on entry and
* restores it before returning. Thus, @ctx will be left pointing to the same
* attribute on return as on entry. However, the actual pointers in @ctx may
* point to different memory locations on return, so you must remember to reset
* any cached pointers from the @ctx, i.e. after the call to
* ntfs_map_runlist_nolock(), you will probably want to do:
* m = ctx->mrec;
* a = ctx->attr;
* Assuming you cache ctx->attr in a variable @a of type ATTR_RECORD * and that
* you cache ctx->mrec in a variable @m of type MFT_RECORD *.
*
* Return 0 on success and -errno on error. There is one special error code
* which is not an error as such. This is -ENOENT. It means that @vcn is out
* of bounds of the runlist.
@ -46,19 +64,32 @@
* Note the runlist can be NULL after this function returns if @vcn is zero and
* the attribute has zero allocated size, i.e. there simply is no runlist.
*
* Locking: - The runlist must be locked for writing.
* - This function modifies the runlist.
* WARNING: If @ctx is supplied, regardless of whether success or failure is
* returned, you need to check IS_ERR(@ctx->mrec) and if TRUE the @ctx
* is no longer valid, i.e. you need to either call
* ntfs_attr_reinit_search_ctx() or ntfs_attr_put_search_ctx() on it.
* In that case PTR_ERR(@ctx->mrec) will give you the error code for
* why the mapping of the old inode failed.
*
* Locking: - The runlist described by @ni must be locked for writing on entry
* and is locked on return. Note the runlist will be modified.
* - If @ctx is NULL, the base mft record of @ni must not be mapped on
* entry and it will be left unmapped on return.
* - If @ctx is not NULL, the base mft record must be mapped on entry
* and it will be left mapped on return.
*/
int ntfs_map_runlist_nolock(ntfs_inode *ni, VCN vcn)
int ntfs_map_runlist_nolock(ntfs_inode *ni, VCN vcn, ntfs_attr_search_ctx *ctx)
{
VCN end_vcn;
unsigned long flags;
ntfs_inode *base_ni;
MFT_RECORD *m;
ATTR_RECORD *a;
ntfs_attr_search_ctx *ctx;
runlist_element *rl;
unsigned long flags;
struct page *put_this_page = NULL;
int err = 0;
BOOL ctx_is_temporary, ctx_needs_reset;
ntfs_attr_search_ctx old_ctx;
ntfs_debug("Mapping runlist part containing vcn 0x%llx.",
(unsigned long long)vcn);
@ -66,20 +97,77 @@ int ntfs_map_runlist_nolock(ntfs_inode *ni, VCN vcn)
base_ni = ni;
else
base_ni = ni->ext.base_ntfs_ino;
m = map_mft_record(base_ni);
if (IS_ERR(m))
return PTR_ERR(m);
ctx = ntfs_attr_get_search_ctx(base_ni, m);
if (unlikely(!ctx)) {
err = -ENOMEM;
goto err_out;
if (!ctx) {
ctx_is_temporary = ctx_needs_reset = TRUE;
m = map_mft_record(base_ni);
if (IS_ERR(m))
return PTR_ERR(m);
ctx = ntfs_attr_get_search_ctx(base_ni, m);
if (unlikely(!ctx)) {
err = -ENOMEM;
goto err_out;
}
} else {
VCN allocated_size_vcn;
BUG_ON(IS_ERR(ctx->mrec));
a = ctx->attr;
BUG_ON(!a->non_resident);
ctx_is_temporary = FALSE;
end_vcn = sle64_to_cpu(a->data.non_resident.highest_vcn);
read_lock_irqsave(&ni->size_lock, flags);
allocated_size_vcn = ni->allocated_size >>
ni->vol->cluster_size_bits;
read_unlock_irqrestore(&ni->size_lock, flags);
if (!a->data.non_resident.lowest_vcn && end_vcn <= 0)
end_vcn = allocated_size_vcn - 1;
/*
* If we already have the attribute extent containing @vcn in
* @ctx, no need to look it up again. We slightly cheat in
* that if vcn exceeds the allocated size, we will refuse to
* map the runlist below, so there is definitely no need to get
* the right attribute extent.
*/
if (vcn >= allocated_size_vcn || (a->type == ni->type &&
a->name_length == ni->name_len &&
!memcmp((u8*)a + le16_to_cpu(a->name_offset),
ni->name, ni->name_len) &&
sle64_to_cpu(a->data.non_resident.lowest_vcn)
<= vcn && end_vcn >= vcn))
ctx_needs_reset = FALSE;
else {
/* Save the old search context. */
old_ctx = *ctx;
/*
* If the currently mapped (extent) inode is not the
* base inode we will unmap it when we reinitialize the
* search context which means we need to get a
* reference to the page containing the mapped mft
* record so we do not accidentally drop changes to the
* mft record when it has not been marked dirty yet.
*/
if (old_ctx.base_ntfs_ino && old_ctx.ntfs_ino !=
old_ctx.base_ntfs_ino) {
put_this_page = old_ctx.ntfs_ino->page;
page_cache_get(put_this_page);
}
/*
* Reinitialize the search context so we can lookup the
* needed attribute extent.
*/
ntfs_attr_reinit_search_ctx(ctx);
ctx_needs_reset = TRUE;
}
}
err = ntfs_attr_lookup(ni->type, ni->name, ni->name_len,
CASE_SENSITIVE, vcn, NULL, 0, ctx);
if (unlikely(err)) {
if (err == -ENOENT)
err = -EIO;
goto err_out;
if (ctx_needs_reset) {
err = ntfs_attr_lookup(ni->type, ni->name, ni->name_len,
CASE_SENSITIVE, vcn, NULL, 0, ctx);
if (unlikely(err)) {
if (err == -ENOENT)
err = -EIO;
goto err_out;
}
BUG_ON(!ctx->attr->non_resident);
}
a = ctx->attr;
/*
@ -89,11 +177,9 @@ int ntfs_map_runlist_nolock(ntfs_inode *ni, VCN vcn)
* ntfs_mapping_pairs_decompress() fails.
*/
end_vcn = sle64_to_cpu(a->data.non_resident.highest_vcn) + 1;
if (unlikely(!a->data.non_resident.lowest_vcn && end_vcn <= 1)) {
read_lock_irqsave(&ni->size_lock, flags);
end_vcn = ni->allocated_size >> ni->vol->cluster_size_bits;
read_unlock_irqrestore(&ni->size_lock, flags);
}
if (!a->data.non_resident.lowest_vcn && end_vcn == 1)
end_vcn = sle64_to_cpu(a->data.non_resident.allocated_size) >>
ni->vol->cluster_size_bits;
if (unlikely(vcn >= end_vcn)) {
err = -ENOENT;
goto err_out;
@ -104,9 +190,93 @@ int ntfs_map_runlist_nolock(ntfs_inode *ni, VCN vcn)
else
ni->runlist.rl = rl;
err_out:
if (likely(ctx))
ntfs_attr_put_search_ctx(ctx);
unmap_mft_record(base_ni);
if (ctx_is_temporary) {
if (likely(ctx))
ntfs_attr_put_search_ctx(ctx);
unmap_mft_record(base_ni);
} else if (ctx_needs_reset) {
/*
* If there is no attribute list, restoring the search context
* is acomplished simply by copying the saved context back over
* the caller supplied context. If there is an attribute list,
* things are more complicated as we need to deal with mapping
* of mft records and resulting potential changes in pointers.
*/
if (NInoAttrList(base_ni)) {
/*
* If the currently mapped (extent) inode is not the
* one we had before, we need to unmap it and map the
* old one.
*/
if (ctx->ntfs_ino != old_ctx.ntfs_ino) {
/*
* If the currently mapped inode is not the
* base inode, unmap it.
*/
if (ctx->base_ntfs_ino && ctx->ntfs_ino !=
ctx->base_ntfs_ino) {
unmap_extent_mft_record(ctx->ntfs_ino);
ctx->mrec = ctx->base_mrec;
BUG_ON(!ctx->mrec);
}
/*
* If the old mapped inode is not the base
* inode, map it.
*/
if (old_ctx.base_ntfs_ino &&
old_ctx.ntfs_ino !=
old_ctx.base_ntfs_ino) {
retry_map:
ctx->mrec = map_mft_record(
old_ctx.ntfs_ino);
/*
* Something bad has happened. If out
* of memory retry till it succeeds.
* Any other errors are fatal and we
* return the error code in ctx->mrec.
* Let the caller deal with it... We
* just need to fudge things so the
* caller can reinit and/or put the
* search context safely.
*/
if (IS_ERR(ctx->mrec)) {
if (PTR_ERR(ctx->mrec) ==
-ENOMEM) {
schedule();
goto retry_map;
} else
old_ctx.ntfs_ino =
old_ctx.
base_ntfs_ino;
}
}
}
/* Update the changed pointers in the saved context. */
if (ctx->mrec != old_ctx.mrec) {
if (!IS_ERR(ctx->mrec))
old_ctx.attr = (ATTR_RECORD*)(
(u8*)ctx->mrec +
((u8*)old_ctx.attr -
(u8*)old_ctx.mrec));
old_ctx.mrec = ctx->mrec;
}
}
/* Restore the search context to the saved one. */
*ctx = old_ctx;
/*
* We drop the reference on the page we took earlier. In the
* case that IS_ERR(ctx->mrec) is true this means we might lose
* some changes to the mft record that had been made between
* the last time it was marked dirty/written out and now. This
* at this stage is not a problem as the mapping error is fatal
* enough that the mft record cannot be written out anyway and
* the caller is very likely to shutdown the whole inode
* immediately and mark the volume dirty for chkdsk to pick up
* the pieces anyway.
*/
if (put_this_page)
page_cache_release(put_this_page);
}
return err;
}
@ -122,8 +292,8 @@ int ntfs_map_runlist_nolock(ntfs_inode *ni, VCN vcn)
* of bounds of the runlist.
*
* Locking: - The runlist must be unlocked on entry and is unlocked on return.
* - This function takes the runlist lock for writing and modifies the
* runlist.
* - This function takes the runlist lock for writing and may modify
* the runlist.
*/
int ntfs_map_runlist(ntfs_inode *ni, VCN vcn)
{
@ -133,7 +303,7 @@ int ntfs_map_runlist(ntfs_inode *ni, VCN vcn)
/* Make sure someone else didn't do the work while we were sleeping. */
if (likely(ntfs_rl_vcn_to_lcn(ni->runlist.rl, vcn) <=
LCN_RL_NOT_MAPPED))
err = ntfs_map_runlist_nolock(ni, vcn);
err = ntfs_map_runlist_nolock(ni, vcn, NULL);
up_write(&ni->runlist.lock);
return err;
}
@ -212,7 +382,7 @@ LCN ntfs_attr_vcn_to_lcn_nolock(ntfs_inode *ni, const VCN vcn,
goto retry_remap;
}
}
err = ntfs_map_runlist_nolock(ni, vcn);
err = ntfs_map_runlist_nolock(ni, vcn, NULL);
if (!write_locked) {
up_write(&ni->runlist.lock);
down_read(&ni->runlist.lock);
@ -325,7 +495,7 @@ runlist_element *ntfs_attr_find_vcn_nolock(ntfs_inode *ni, const VCN vcn,
goto retry_remap;
}
}
err = ntfs_map_runlist_nolock(ni, vcn);
err = ntfs_map_runlist_nolock(ni, vcn, NULL);
if (!write_locked) {
up_write(&ni->runlist.lock);
down_read(&ni->runlist.lock);

3
fs/ntfs/attrib.h
View file

@ -60,7 +60,8 @@ typedef struct {
ATTR_RECORD *base_attr;
} ntfs_attr_search_ctx;
extern int ntfs_map_runlist_nolock(ntfs_inode *ni, VCN vcn);
extern int ntfs_map_runlist_nolock(ntfs_inode *ni, VCN vcn,
ntfs_attr_search_ctx *ctx);
extern int ntfs_map_runlist(ntfs_inode *ni, VCN vcn);
extern LCN ntfs_attr_vcn_to_lcn_nolock(ntfs_inode *ni, const VCN vcn,