| Message ID | 20180125174752.5139-1-aaptel@suse.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Reviewed-by: Ronnie Sahlberg <lsahlber@redhat.com> On Fri, Jan 26, 2018 at 3:47 AM, Aurelien Aptel <aaptel@suse.com> wrote: > Signed-off-by: Aurelien Aptel <aaptel@suse.com> > --- > fs/cifs/connect.c | 32 +++++++++++++++++++++++++++++++- > 1 file changed, 31 insertions(+), 1 deletion(-) > > diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c > index 8b5e401f547a..ff7a653fd322 100644 > --- a/fs/cifs/connect.c > +++ b/fs/cifs/connect.c > @@ -2704,6 +2704,13 @@ cifs_set_cifscreds(struct smb_vol *vol __attribute__((unused)), > } > #endif /* CONFIG_KEYS */ > > +/** > + * cifs_get_smb_ses - get a session matching @volume_info data from @server > + * > + * This function assumes it is being called from cifs_mount() where we > + * already got a server reference (server refcount +1). See > + * cifs_get_tcon() for refcount explanations. > + */ > static struct cifs_ses * > cifs_get_smb_ses(struct TCP_Server_Info *server, struct smb_vol *volume_info) > { > @@ -2877,6 +2884,26 @@ cifs_put_tcon(struct cifs_tcon *tcon) > cifs_put_smb_ses(ses); > } > > +/** > + * cifs_get_tcon - get a tcon matching @volume_info data from @ses > + * > + * - tcon refcount is the number of mount points using the tcon. > + * - ses refcount is the number of tcon using the session. > + * > + * 1. This function assumes it is being called from cifs_mount() where > + * we already got a session reference (ses refcount +1). > + * > + * 2. Since we're in the context of adding a mount point, the end > + * result should be either: > + * > + * a) a new tcon already allocated with refcount=1 (1 mount point) and > + * its session refcount incremented (1 new tcon). This +1 was > + * already done in (1). > + * > + * b) an existing tcon with refcount+1 (add a mount point to it) and > + * identical ses refcount (no new tcon). Because of (1) we need to > + * decrement the ses refcount. > + */ > static struct cifs_tcon * > cifs_get_tcon(struct cifs_ses *ses, struct smb_vol *volume_info) > { > @@ -2885,8 +2912,11 @@ cifs_get_tcon(struct cifs_ses *ses, struct smb_vol *volume_info) > > tcon = cifs_find_tcon(ses, volume_info); > if (tcon) { > + /* > + * tcon has refcount already incremented but we need to > + * decrement extra ses reference gotten by caller (case b) > + */ > cifs_dbg(FYI, "Found match on UNC path\n"); > - /* existing tcon already has a reference */ > cifs_put_smb_ses(ses); > return tcon; > } > -- > 2.12.3 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-cifs" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-cifs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/fs/cifs/connect.c b/fs/cifs/connect.c index 8b5e401f547a..ff7a653fd322 100644 --- a/fs/cifs/connect.c +++ b/fs/cifs/connect.c @@ -2704,6 +2704,13 @@ cifs_set_cifscreds(struct smb_vol *vol __attribute__((unused)), } #endif /* CONFIG_KEYS */ +/** + * cifs_get_smb_ses - get a session matching @volume_info data from @server + * + * This function assumes it is being called from cifs_mount() where we + * already got a server reference (server refcount +1). See + * cifs_get_tcon() for refcount explanations. + */ static struct cifs_ses * cifs_get_smb_ses(struct TCP_Server_Info *server, struct smb_vol *volume_info) { @@ -2877,6 +2884,26 @@ cifs_put_tcon(struct cifs_tcon *tcon) cifs_put_smb_ses(ses); } +/** + * cifs_get_tcon - get a tcon matching @volume_info data from @ses + * + * - tcon refcount is the number of mount points using the tcon. + * - ses refcount is the number of tcon using the session. + * + * 1. This function assumes it is being called from cifs_mount() where + * we already got a session reference (ses refcount +1). + * + * 2. Since we're in the context of adding a mount point, the end + * result should be either: + * + * a) a new tcon already allocated with refcount=1 (1 mount point) and + * its session refcount incremented (1 new tcon). This +1 was + * already done in (1). + * + * b) an existing tcon with refcount+1 (add a mount point to it) and + * identical ses refcount (no new tcon). Because of (1) we need to + * decrement the ses refcount. + */ static struct cifs_tcon * cifs_get_tcon(struct cifs_ses *ses, struct smb_vol *volume_info) { @@ -2885,8 +2912,11 @@ cifs_get_tcon(struct cifs_ses *ses, struct smb_vol *volume_info) tcon = cifs_find_tcon(ses, volume_info); if (tcon) { + /* + * tcon has refcount already incremented but we need to + * decrement extra ses reference gotten by caller (case b) + */ cifs_dbg(FYI, "Found match on UNC path\n"); - /* existing tcon already has a reference */ cifs_put_smb_ses(ses); return tcon; }
Signed-off-by: Aurelien Aptel <aaptel@suse.com> --- fs/cifs/connect.c | 32 +++++++++++++++++++++++++++++++- 1 file changed, 31 insertions(+), 1 deletion(-)